INSR

Gene Summary

Gene:INSR; insulin receptor
Aliases: HHF5, CD220
Location:19p13.2
Summary:This gene encodes a member of the receptor tyrosine kinase family of proteins. The encoded preproprotein is proteolytically processed to generate alpha and beta subunits that form a heterotetrameric receptor. Binding of insulin or other ligands to this receptor activates the insulin signaling pathway, which regulates glucose uptake and release, as well as the synthesis and storage of carbohydrates, lipids and protein. Mutations in this gene underlie the inherited severe insulin resistance syndromes including type A insulin resistance syndrome, Donohue syndrome and Rabson-Mendenhall syndrome. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Oct 2015]
Databases:VEGA, OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:insulin receptor
Source:NCBIAccessed: 11 March, 2017

Ontology:

What does this gene/protein do?
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Pathways:What pathways are this gene/protein implicaed in?
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Cancer Overview

Research Indicators

Publications Per Year (1992-2017)
Graph generated 11 March 2017 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

  • Validation Studies as Topic
  • Xenograft Models
  • Genotype
  • IGF1R
  • Neoplasm Proteins
  • Exons
  • Insulin Receptor Substrate Proteins
  • Severity of Illness Index
  • Young Adult
  • Genetic Predisposition
  • Chromosome 19
  • Alleles
  • CD Antigens
  • Steroids
  • Cell Proliferation
  • Colorectal Cancer
  • Receptors, FSH
  • Body Mass Index
  • Stomach Cancer
  • Obesity
  • Estrogen Receptors
  • Insulin-Like Growth Factor I
  • Up-Regulation
  • Apoptosis
  • Breast Cancer
  • Translocation
  • Adolescents
  • Insulin Resistance
  • Transcription
  • Single Nucleotide Polymorphism
  • Case-Control Studies
  • Protein Transport
  • Insulin
  • Protein-Tyrosine Kinases
  • Signal Transduction
  • Gene Expression Profiling
  • Drug Resistance
  • Risk Factors
  • Cancer Gene Expression Regulation
Tag cloud generated 11 March, 2017 using data from PubMed, MeSH and CancerIndex

Specific Cancers (3)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: INSR (cancer-related)

Usset JL, Raghavan R, Tyrer JP, et al.
Assessment of Multifactor Gene-Environment Interactions and Ovarian Cancer Risk: Candidate Genes, Obesity, and Hormone-Related Risk Factors.
Cancer Epidemiol Biomarkers Prev. 2016; 25(5):780-90 [PubMed] Article available free on PMC after 01/05/2017 Related Publications
BACKGROUND: Many epithelial ovarian cancer (EOC) risk factors relate to hormone exposure and elevated estrogen levels are associated with obesity in postmenopausal women. Therefore, we hypothesized that gene-environment interactions related to hormone-related risk factors could differ between obese and non-obese women.
METHODS: We considered interactions between 11,441 SNPs within 80 candidate genes related to hormone biosynthesis and metabolism and insulin-like growth factors with six hormone-related factors (oral contraceptive use, parity, endometriosis, tubal ligation, hormone replacement therapy, and estrogen use) and assessed whether these interactions differed between obese and non-obese women. Interactions were assessed using logistic regression models and data from 14 case-control studies (6,247 cases; 10,379 controls). Histotype-specific analyses were also completed.
RESULTS: SNPs in the following candidate genes showed notable interaction: IGF1R (rs41497346, estrogen plus progesterone hormone therapy, histology = all, P = 4.9 × 10(-6)) and ESR1 (rs12661437, endometriosis, histology = all, P = 1.5 × 10(-5)). The most notable obesity-gene-hormone risk factor interaction was within INSR (rs113759408, parity, histology = endometrioid, P = 8.8 × 10(-6)).
CONCLUSIONS: We have demonstrated the feasibility of assessing multifactor interactions in large genetic epidemiology studies. Follow-up studies are necessary to assess the robustness of our findings for ESR1, CYP11A1, IGF1R, CYP11B1, INSR, and IGFBP2 Future work is needed to develop powerful statistical methods able to detect these complex interactions.
IMPACT: Assessment of multifactor interaction is feasible, and, here, suggests that the relationship between genetic variants within candidate genes and hormone-related risk factors may vary EOC susceptibility. Cancer Epidemiol Biomarkers Prev; 25(5); 780-90. ©2016 AACR.

Casarini L, Simoni M, Brigante G
Is polycystic ovary syndrome a sexual conflict? A review.
Reprod Biomed Online. 2016; 32(4):350-61 [PubMed] Related Publications
Several studies have attempted to explain the high overall prevalence of polycystic ovary syndrome among women worldwide (about 4-10%) despite its link to subfertile phenotypes. For this reason, it is considered an evolutionary paradox. In this review, we show that several genetic loci associated with the disease differently modulate the reproductive parameters of men and women. This observation suggests that such genetic variants lead to opposite effects in the two sexes in reproductive success. Intralocus sexual conflict as a cause of the persistence polycystic ovary syndrome genotypes among humans is supported.

Gangopadhyay S, Agrawal N, Batra A, et al.
Single-Nucleotide Polymorphism on Exon 17 of Insulin Receptor Gene Influences Insulin Resistance in PCOS: A Pilot Study on North Indian Women.
Biochem Genet. 2016; 54(2):158-68 [PubMed] Related Publications
Polycystic ovarian syndrome (PCOS), a major cause of infertility, is also strongly associated with insulin resistance. Defects in insulin receptor signaling are considered as one of the major molecular pathogeneses for insulin resistance. To investigate the possible mechanism of this signaling defect at genetic level, single-nucleotide polymorphism (SNP) [His 1085 C/T] at the exon 17 of insulin receptor gene (INSR) was studied in this pilot study. Polymerase chain reaction was performed on leucocytic DNA of women diagnosed with PCOS, selected from the outpatient department of Safdarjung Hospital, New Delhi, using suitable primer to amplify a region on INSR. An equal number of age-matched healthy women were selected as controls. SNP analysis was performed with restriction enzyme length polymorphism technique using Pm II enzyme. Serum insulin level was measured by ELISA kit and HOMA-IR was calculated mathematically. A higher frequency of the CC genotype was observed in PCOS women than in controls. Also, HOMA-IR, a tool for estimating insulin resistance, was significantly high in PCOS women with the CC genotype. C1008T SNP at exon 17 of INSR is associated with insulin resistance in Indian women with PCOS. Presence of CC genotype (C1085T) could be developed as a marker for insulin resistance and metabolic complications in PCOS women.

Sanderson MP, Apgar J, Garin-Chesa P, et al.
BI 885578, a Novel IGF1R/INSR Tyrosine Kinase Inhibitor with Pharmacokinetic Properties That Dissociate Antitumor Efficacy and Perturbation of Glucose Homeostasis.
Mol Cancer Ther. 2015; 14(12):2762-72 [PubMed] Related Publications
Inhibition of the IGF1R, INSRA, and INSRB receptor tyrosine kinases represents an attractive approach of pharmacologic intervention in cancer, owing to the roles of the IGF1R and INSRA in promoting cell proliferation and survival. However, the central role of the INSRB isoform in glucose homeostasis suggests that prolonged inhibition of this kinase could result in metabolic toxicity. We describe here the profile of the novel compound BI 885578, a potent and selective ATP-competitive IGF1R/INSR tyrosine kinase inhibitor distinguished by rapid intestinal absorption and a short in vivo half-life as a result of rapid metabolic clearance. BI 885578, administered daily per os, displayed an acceptable tolerability profile in mice at doses that significantly reduced the growth of xenografted human GEO and CL-14 colon carcinoma tumors. We found that treatment with BI 885578 is accompanied by increases in circulating glucose and insulin levels, which in turn leads to compensatory hyperphosphorylation of muscle INSRs and subsequent normalization of blood glucose within a few hours. In contrast, the normalization of IGF1R and INSR phosphorylation in GEO tumors occurs at a much slower rate. In accordance with this, BI 885578 led to a prolonged inhibition of cell proliferation and induction of apoptosis in GEO tumors. We propose that the remarkable therapeutic window observed for BI 885578 is achieved by virtue of the distinctive pharmacokinetic properties of the compound, capitalizing on the physiologic mechanisms of glucose homeostasis and differential levels of IGF1R and INSR expression in tumors and normal tissues.

Mohlin S, Hamidian A, von Stedingk K, et al.
PI3K-mTORC2 but not PI3K-mTORC1 regulates transcription of HIF2A/EPAS1 and vascularization in neuroblastoma.
Cancer Res. 2015; 75(21):4617-28 [PubMed] Related Publications
Hypoxia-inducible factor (HIF) is a master regulator of cellular responses to oxygen deprival with a critical role in mediating the angiogenic switch in solid tumors. Differential expression of the HIF subunits HIF1α and HIF2α occurs in many human tumor types, suggesting selective implications to biologic context. For example, high expression of HIF2α that occurs in neuroblastoma is associated with stem cell-like features, disseminated disease, and poor clinical outcomes, suggesting pivotal significance for HIF2 control in neuroblastoma biology. In this study, we provide novel insights into how HIF2α expression is transcriptionally controlled by hypoxia and how this control is abrogated by inhibition of insulin-like growth factor-1R/INSR-driven phosphoinositide 3-kinase (PI3K) signaling. Reducing PI3K activity was sufficient to decrease HIF2α mRNA and protein expression in a manner with smaller and less vascularized tumors in vivo. PI3K-regulated HIF2A mRNA expression was independent of Akt or mTORC1 signaling but relied upon mTORC2 signaling. HIF2A mRNA was induced by hypoxia in neuroblastoma cells isolated from metastatic patient-derived tumor xenografts, where HIF2A levels could be reduced by treatment with PI3K and mTORC2 inhibitors. Our results suggest that targeting PI3K and mTORC2 in aggressive neuroblastomas with an immature phenotype may improve therapeutic efficacy.

Aljada A, Saleh AM, Al-Aqeel SM, et al.
Quantification of insulin receptor mRNA splice variants as a diagnostic tumor marker in breast cancer.
Cancer Biomark. 2015; 15(5):653-61 [PubMed] Related Publications
BACKGROUND: The mature human insulin receptor (INSR) has two isoforms: The A isoform and the B isoform. INSR upregulation has been suggested to play a role in cancer.
OBJECTIVE: To establish quantitative PCR method for INSR transcript variants and examine their differential expression as a diagnostic tumor marker in breast cancer.
METHODS: The differential expression of IR-A and IR-B were evaluated by TaqMan qRT-PCR assay in the commercially available Breast Cancer Disease cDNA and Cancer Survey cDNA arrays.
RESULTS: The mRNA expression levels of IR-A was statistically significantly higher in breast cancer when compared to normal breast tissue while IR-B mRNA expression was down regulated significantly in breast cancer. Stratification of patients into groups according to metastatic stages indicated statistically significantly higher levels of IR-A mRNA in clinical stage (CS)-IV, and lower IR-B levels in CS-IIA, CS-IIIB and CS-IIIC. However, IR-A:IR-B ratio showed a statistically significant increase in all stages. Cancer Survey cDNA array demonstrated lower levels of IR-B mRNA in breast adenocarcinoma, liver carcinoma and lung carcinoma only while IR-A expression was significantly altered in kidney carcinoma without any significant differences in IR-A:IR-B ratios.
CONCLUSIONS: The results demonstrate an increased IR-A:IR-B ratio in all clinical stages of breast cancer. Thus, IR-A:IR-B ratio may have a diagnostic biomarker utility in breast cancer.

Jones MR, Brower MA, Xu N, et al.
Systems Genetics Reveals the Functional Context of PCOS Loci and Identifies Genetic and Molecular Mechanisms of Disease Heterogeneity.
PLoS Genet. 2015; 11(8):e1005455 [PubMed] Article available free on PMC after 01/05/2017 Related Publications
Genome wide association studies (GWAS) have revealed 11 independent risk loci for polycystic ovary syndrome (PCOS), a common disorder in young women characterized by androgen excess and oligomenorrhea. To put these risk loci and the single nucleotide polymorphisms (SNPs) therein into functional context, we measured DNA methylation and gene expression in subcutaneous adipose tissue biopsies to identify PCOS-specific alterations. Two genes from the LHCGR region, STON1-GTF2A1L and LHCGR, were overexpressed in PCOS. In analysis stratified by obesity, LHCGR was overexpressed only in non-obese PCOS women. Although not differentially expressed in the entire PCOS group, INSR was underexpressed in obese PCOS subjects only. Alterations in gene expression in the LHCGR, RAB5B and INSR regions suggest that SNPs in these loci may be functional and could affect gene expression directly or indirectly via epigenetic alterations. We identified reduced methylation in the LHCGR locus and increased methylation in the INSR locus, changes that are concordant with the altered gene expression profiles. Complex patterns of meQTL and eQTL were identified in these loci, suggesting that local genetic variation plays an important role in gene regulation. We propose that non-obese PCOS women possess significant alterations in LH receptor expression, which drives excess androgen secretion from the ovary. Alternatively, obese women with PCOS possess alterations in insulin receptor expression, with underexpression in metabolic tissues and overexpression in the ovary, resulting in peripheral insulin resistance and excess ovarian androgen production. These studies provide a genetic and molecular basis for the reported clinical heterogeneity of PCOS.

ter Braak B, Wink S, Koedoot E, et al.
Alternative signaling network activation through different insulin receptor family members caused by pro-mitogenic antidiabetic insulin analogues in human mammary epithelial cells.
Breast Cancer Res. 2015; 17:97 [PubMed] Article available free on PMC after 01/05/2017 Related Publications
INTRODUCTION: Insulin analogues are designed to have improved pharmacokinetic parameters compared to regular human insulin. This provides a sustained control of blood glucose levels in diabetic patients. All novel insulin analogues are tested for their mitogenic side effects, however these assays do not take into account the molecular mode of action of different insulin analogues. Insulin analogues can bind the insulin receptor and the insulin-like growth factor 1 receptor with different affinities and consequently will activate different downstream signaling pathways.
METHODS: Here we used a panel of MCF7 human breast cancer cell lines that selectively express either one of the isoforms of the INSR or the IGF1R. We applied a transcriptomics approach to assess the differential transcriptional programs activated in these cells by either insulin, IGF1 or X10 treatment.
RESULTS: Based on the differentially expressed genes between insulin versus IGF1 and X10 treatment, we retrieved a mitogenic classifier gene set. Validation by RT-qPCR confirmed the robustness of this gene set. The translational potential of these mitogenic classifier genes was examined in primary human mammary cells and in mammary gland tissue of mice in an in vivo model. The predictive power of the classifier genes was evaluated by testing all commercial insulin analogues in the in vitro model and defined X10 and glargine as the most potent mitogenic insulin analogues.
CONCLUSIONS: We propose that these mitogenic classifier genes can be used to test the mitogenic potential of novel insulin analogues as well as other alternative molecules with an anticipated affinity for the IGF1R.

Frisch CM, Zimmermann K, Zilleßen P, et al.
Non-small cell lung cancer cell survival crucially depends on functional insulin receptors.
Endocr Relat Cancer. 2015; 22(4):609-21 [PubMed] Related Publications
Insulin plays an important role as a growth factor and its contribution to tumor proliferation is intensely discussed. It acts via the cognate insulin receptor (IR) but can also activate the IGF1 receptor (IGF1R). Apart from increasing proliferation, insulin might have additional effects in lung cancer. Therefore, we investigated insulin action and effects of IR knockdown (KD) in three (NCI-H292, NCI-H226 and NCI-H460) independent non-small cell lung cancer (NSCLC) cell lines. All lung cancer lines studied were found to express IR, albeit with marked differences in the ratio of the two variants IR-A and IR-B. Insulin activated the classical signaling pathway with IR autophosphorylation and Akt phosphorylation. Moreover, activation of MAPK was observed in H292 cells, accompanied by enhanced proliferation. Lentiviral shRNA IR KD caused strong decrease in survival of all three lines, indicating that the effects of insulin in lung cancer go beyond enhancing proliferation. Unspecific effects were ruled out by employing further shRNAs and different insulin-responsive cells (human pre-adipocytes) for comparison. Caspase assays demonstrated that IR KD strongly induced apoptosis in these lung cancer cells, providing the physiological basis of the rapid cell loss. In search for the underlying mechanism, we analyzed alterations in the gene expression profile in response to IR KD. A strong induction of certain cytokines (e.g. IL20 and tumour necrosis factor) became obvious and it turned out that these cytokines trigger apoptosis in the NSCLC cells tested. This indicates a novel role of IR in tumor cell survival via suppression of pro-apoptotic cytokines.

Parekh N, Guffanti G, Lin Y, et al.
Insulin receptor variants and obesity-related cancers in the Framingham Heart Study.
Cancer Causes Control. 2015; 26(8):1189-95 [PubMed] Related Publications
PURPOSE: The insulin-signaling pathway plays a pivotal role in cancer biology; however, evidence of genetic alterations in human studies is limited. This case-control study nested within the Framingham Heart Study (FHS) examined the association between inherited genetic variation in the insulin receptor (INSR) gene and obesity-related cancer risk.
METHODS: The study sample consisted of 1,475 controls and 396 cases from the second familial generation of the FHS. Participants who provided consent were genotyped. Nineteen single-nucleotide polymorphisms (SNPs) in the INSR gene were investigated in relation to risk of obesity-related cancers combined and breast, prostate and colorectal cancers. Generalized estimation equation models controlling for familial correlations and include age, sex, smoking and body mass index as covariates, assuming additive models, were used.
RESULTS: Three SNPs, rs2059807, s8109559 and rs919275, were significantly associated with obesity-related cancers (p value < 0.02) with the most significantly associated SNP being rs2059807 (p value = 0.008). Carriers of two copies of SNP rs2059807 risk allele T were significantly less prevalent among subjects with obesity-related cancers [f(TT)cases = 14 vs. f(TT)controls = 18 %; OR 1.23]. In exploratory analyses evaluating site-specific cancers, the INSR rs2059807 association with these cancers was consistent with that observed for the main outcome (ORs colorectal cancer = 1.5, breast cancer = 1.29, prostate = 1.06). There was no statistically significant interaction between the INSR-SNP and blood glucose in relation to obesity-related cancer.
CONCLUSIONS: The INSR gene is implicated in obesity-related cancer risk, as 3 of 19 SNPs were nominally associated, after false discovery rate (FDR) correction, with the main outcome. Risk allele homozygotes (rs2059807) were less prevalent among subjects with obesity-related cancer. These results should be replicated in other populations to confirm the findings.

Kiflemariam S, Ljungström V, Pontén F, Sjöblom T
Tumor vessel up-regulation of INSR revealed by single-cell expression analysis of the tyrosine kinome and phosphatome in human cancers.
Am J Pathol. 2015; 185(6):1600-9 [PubMed] Related Publications
The tyrosine kinome and phosphatome harbor oncogenes and tumor suppressor genes and important regulators of angiogenesis and tumor stroma formation. To provide a better understanding of their potential roles in cancer, we analyzed the expression of 85 tyrosine kinases and 42 tyrosine phosphatases by in situ hybridization 48 human normal and 24 tumor tissue specimens. Nine-tenths of the assessed transcripts had tumor cell expression concordant with expression array databases. Further, pan-cancer expression of AATK, PTPRK, and PTPRU and expression of PTPRS in a subset of tumors were observed. To demonstrate tumor subcompartment resolution, we validated the predicted tumor stroma-specific markers HTRA1, HTRA3, MXRA5, MXRA8, and SERPING1 in situ. In addition to known vascular and stromal markers such as PDGFRB, we observed stromal expression of PTK6 and TNS1 and vascular expression of INSR, PTPRF, PTPRG, PTPRU, and TNS1, of which INSR emerged as a tumor-specific vessel marker. This study demonstrates the feasibility of large-scale analyses to chart the transcriptome in situ in human cancers and their ability to identify novel cancer biomarkers.

Tarnowski M, Tkacz M, Czerewaty M, et al.
5‑Azacytidine inhibits human rhabdomyosarcoma cell growth by downregulating insulin‑like growth factor 2 expression and reactivating the H19 gene product miR‑675, which negatively affects insulin‑like growth factors and insulin signaling.
Int J Oncol. 2015; 46(5):2241-50 [PubMed] Related Publications
Insulin-like growth factor 2 (IGF2) and 1 (IGF1) and insulin (INS) promote proliferation of rhabdomyosarcoma (RMS) cells by interacting with the insulin-like growth factor 1 receptor (IGF1R) and the insulin receptor (INSR). Loss of imprinting (LOI) by DNA hypermethylation at the differentially methylated region (DMR) for the IGF2‑H19 locus is commonly observed in RMS cells and results in an increase in the expression of proliferation-promoting IGF2 and downregulation of proliferation-inhibiting non-coding H19 miRNAs. One of these miRNAs, miR‑675, has been reported in murine cells to be a negative regulator of IGF1R expression. To better address the role of IGF2 and 1, as well as INS signaling in the pathogenesis of RMS and the involvement of LOI at the IGF2‑H19 locus, we employed the DNA demethylating agent 5‑azacytidine (AzaC). We observed that AzaC‑mediated demethylation of the DMR at the IGF2‑H19 locus resulted in downregulation of IGF2 and an increase in the expression of H19. This epigenetic change resulted in a decrease in RMS proliferation due to downregulation of IGF2 and, IGF1R expression in an miR‑675‑dependent manner. Interestingly, we observed that miR‑675 not only inhibited the expression of IGF1R in a similar manner in human and murine cells, but we also observed its negative effect on the expression of the INSR. These results confirm the crucial role of LOI at the IGF2‑H19 DMR in the pathogenesis of RMS and are relevant to the development of new treatment strategies.

Feng C, Lv PP, Yu TT, et al.
The association between polymorphism of INSR and polycystic ovary syndrome: a meta-analysis.
Int J Mol Sci. 2015; 16(2):2403-25 [PubMed] Article available free on PMC after 01/05/2017 Related Publications
Polycystic ovary syndrome (PCOS) is the most common gynecological endocrine disorder. The genetic background is believed to play a crucial role in the pathogenesis of PCOS. In recent years, the role of insulin receptor (INSR) polymorphisms in PCOS predisposition has attracted much attention. We performed a meta-analysis to investigate the association between the single nucleotide polymorphisms (SNPs) of INSR and PCOS. Published literature from Pubmed, Embase, and Cochrane CENTRAL was retrieved up until 7 August 2014. A total of 20 case-control studies including 23,845 controls and 17,460 PCOS cases with an average Newcastle-Ottawa quality assessment scale (NOS) score of 6.75 were analyzed. Ninety-eight SNPs distributed in 23 exons and the flanking regions of INSR were investigated, among which 17 SNPs were found to be associated with PCOS. Three SNPs detected in more than three studies were selected for further analyses. Twelve studies including 1158 controls and 1264 PCOS cases entered the analysis of rs1799817, but no significant association was found for every genotype (p > 0.05). Further subgroup stratification by ethnicity and weight did not lead to discovery of significant correlation (p > 0.05). For rs2059806, four studies including 442 controls and 524 PCOS cases were qualified for meta-analysis, and no significant association with PCOS was found for any genotype (p > 0.05). Four studies including 12,830 controls and 11,683 PCOS cases investigated the correlation between rs2059807 and PCOS, and five of the six cohorts indicated a significant impact. Our current meta-analysis suggests no significant correlation between rs1799817/rs2059806 SNPs and susceptibility of PCOS, while rs2059807 could be a promising candidate SNP that might be involved in the susceptibility of PCOS.

McAllister JM, Legro RS, Modi BP, Strauss JF
Functional genomics of PCOS: from GWAS to molecular mechanisms.
Trends Endocrinol Metab. 2015; 26(3):118-24 [PubMed] Article available free on PMC after 01/05/2017 Related Publications
Polycystic ovary syndrome (PCOS) is a common endocrinopathy characterized by increased ovarian androgen biosynthesis, anovulation, and infertility. PCOS has a strong heritable component based on familial clustering and twin studies. Genome-wide association studies (GWAS) identified several PCOS candidate loci including LHCGR, FSHR, ZNF217, YAP1, INSR, RAB5B, and C9orf3. We review the functional roles of strong PCOS candidate loci focusing on FSHR, LHCGR, INSR, and DENND1A. We propose that these candidates comprise a hierarchical signaling network by which DENND1A, LHCGR, INSR, RAB5B, adapter proteins, and associated downstream signaling cascades converge to regulate theca cell androgen biosynthesis. Future elucidation of the functional gene networks predicted by the PCOS GWAS will result in new diagnostic and therapeutic approaches for women with PCOS.

Cui L, Li G, Zhong W, et al.
Polycystic ovary syndrome susceptibility single nucleotide polymorphisms in women with a single PCOS clinical feature.
Hum Reprod. 2015; 30(3):732-6 [PubMed] Related Publications
STUDY QUESTION: What is the direct genetic contribution of the polycystic ovary syndrome (PCOS) susceptibility single nucleotide polymorphisms (SNPs), identified by previous genome-wide association studies (GWAS) to the definitive clinical features of the syndrome?
SUMMARY ANSWER: Each single PCOS clinical feature had a specific genetic association, and rs4385527 in the chromosome 9 open reading frame 3 (C9orf3) conferred a particular risk to the three defined PCOS clinical features in this study, which suggested its fundamental role in the etiology of PCOS.
WHAT IS KNOWN ALREADY: PCOS is a heterogeneous disorder characterized by anovulation (OA), hyperandrogenism (HA) and polycystic ovary morphology (PCOM). Two previous GWAS in China have identified 15 independent susceptibility SNPs related to PCOS (PCOS-SNPs). However, little is known about the candidate gene of each clinical feature.
STUDY DESIGN, SIZE, DURATION: Case-control study. Three independent groups of women were recruited from 2010 to 2012: 746 subjects with OA only, 278 subjects with HA only and 536 subjects with PCOM only. A total of 1790 healthy women with none of the above pathological characteristics were also enrolled as control subjects during the same time period.
PARTICIPANTS/MATERIALS, SETTING, METHODS: All participants were women of reproductive age. Genotype and allelic frequencies of 15 PCOS-SNPs were determined in all subjects using direct sequencing and Sequenom Arrays. The allelic frequencies of each case group were compared with the controls.
MAIN RESULTS AND THE ROLE OF CHANCE: After adjustment for age and BMI, variants in luteinizing hormone/choriogonadotropin receptor (LHCGR) (rs13405728), C9orf3 (rs4385527) and insulin receptor gene (INSR) (rs2059807) were strongly associated with OA (Padjust < 0.01, <0.001 and <0.05, respectively); rs4385527 in C9orf3 was strongly associated with HA (Padjust< 0.001); variants in the thyroid adenoma associated gene (THADA) (rs13429458 and rs12478601), DENN/MADD domain containing 1A (DENND1A)(rs10818854), and C9orf3 (rs4385527) were significantly associated with PCOM (Padjust < 0.01, <0.001, <0.05 and <0.001, respectively).
LIMITATIONS, REASONS FOR CAUTION: The sample size of some case groups was relatively small, which therefore limited the statistical power of the analysis to a certain extent.
WIDER IMPLICATIONS OF THE FINDINGS: The present study indicates a potential common genetic basis of three PCOS clinical features. Other specific associated genes may play a synergistic role, leading to heterogeneous pathophysiological changes. Additionally, the increased frequency of PCOS-risk alleles in women with single PCOS clinical features suggests that these subjects have an elevated risk of developing the syndrome, although they cannot be currently diagnosed.
STUDY FUNDING/COMPETING INTERESTS: This research was supported by the National Basic Research Program of China (973 Program) (2012CB944700, 2011CB944502), the National Key Technology Research and Development Program(2011BAI17B00), the National Natural Science Foundation of China (81430029, 81201441, 81490743, 31371453), the Scientific Research Foundation of Shandong Province of Outstanding Young Scientist (2012BSE27089) and the Fundamental Research Funds of Shandong University(2014GN025). There were no competing interests.

Donner I, Kiviluoto T, Ristimäki A, et al.
Exome sequencing reveals three novel candidate predisposition genes for diffuse gastric cancer.
Fam Cancer. 2015; 14(2):241-6 [PubMed] Related Publications
Gastric cancer is the fourth most common cancer worldwide and the second leading cause of cancer mortality. Three hereditary gastric cancer syndromes have been described; hereditary diffuse gastric cancer (HDGC), familial intestinal gastric cancer (FIGC) and gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS). Thirty per cent of HDGC families have heterozygous germline mutations in CDH1, which encodes E-cadherin. A germline truncating mutation in the gene encoding α-E-catenin (CTNNA1) was also recently discovered in a family with HDGC, but no other genes specifically predisposing to gastric cancer have been identified, leaving the majority of cases showing familial aggregation without a known genetic cause. The aim of this study was to find the putative gastric cancer predisposing gene defect in a family with HDGC that had previously been tested negative for mutations in CDH1. In this family, there were six cases of diffuse gastric cancer in two generations. Exome sequencing was applied to two affected family members. The shared variants which were predicted deleterious in silico and could not be found in databases or in a control set of over 4,000 individuals were Sanger sequenced in a third family member. Three candidate variants were identified: p.Glu1313Lys in Insulin receptor (INSR), p.Arg81Pro in F-box protein 24 (FBXO24) and p.Pro1146Leu in DOT1-like histone H3K79 methyltransferase (DOT1L). These variants and adjacent regions were screened for in an additional 26 gastric cancer patients with a confirmed (n = 13) or suspected (n = 13) family history of disease, but no other non-synonymous mutations were identified. This study identifies INSR, FBXO24 and DOT1L as new candidate diffuse gastric cancer susceptibility genes, which should be validated in other populations. Of these genes, INSR is of special interest as insulin signaling was recently shown to affect tumor cell invasion capability by modulating E-cadherin glycosylation.

Mahmoudi T, Majidzadeh-A K, Karimi K, et al.
An exon variant in insulin receptor gene is associated with susceptibility to colorectal cancer in women.
Tumour Biol. 2015; 36(5):3709-15 [PubMed] Related Publications
Given the role of insulin resistance in colorectal cancer (CRC), we explored whether genetic variants in insulin (INS), insulin receptor (INSR), insulin receptor substrate 1 (IRS1), insulin receptor substrate 2 (IRS2), insulin-like growth factor 1 (IGF1), and insulin-like growth factor binding protein 3 (IGFBP3) genes were associated with CRC risk. A total of 600 subjects, including 261 cases with CRC and 339 controls, were enrolled in this case-control study. Six polymorphisms in INS (rs689), INSR (rs1799817), IRS1 (rs1801278), IRS2 (rs1805097), IGF1 (rs5742612), and IGFBP3 (rs2854744) genes were genotyped using PCR-RFLP method. No significant difference was observed for INS, INSR, IRS1, IRS2, IGF1, and IGFBP3 genes between the cases and controls. However, the INSR rs1799817 "TT + CT" genotype and "CT" genotype compared with "CC" genotype occurred more frequently in the women with CRC than women controls (P = 0.007; OR = 1.93, 95 %CI = 1.20-3.11 and P = 0.002, OR = 2.15, 95 %CI = 1.31-3.53, respectively), and the difference remained significant after adjustment for confounding factors including age, BMI, smoking status, NSAID use, and family history of CRC (P = 0.018; OR = 1.86, 95 %CI = 1.11-3.10 and P = 0.004, OR = 2.18, 95 %CI = 1.28-3.71, respectively). In conclusion, to our knowledge, this study indicated for the first time that the INSR rs1799817 TT + CT genotype and CT genotype compared with the CC genotype had 1.86-fold and 2.18-fold increased risks for CRC among women, respectively. Furthermore, this finding is in line with previous studies which found significant associations between other variants of the INSR gene and CRC risk. Nevertheless, further studies are required to confirm our findings.

Schmit SL, Gollub J, Shapero MH, et al.
MicroRNA polymorphisms and risk of colorectal cancer.
Cancer Epidemiol Biomarkers Prev. 2015; 24(1):65-72 [PubMed] Article available free on PMC after 01/05/2017 Related Publications
BACKGROUND: miRNAs act as post-transcriptional regulators of gene expression. Genetic variation in miRNA-encoding sequences or their corresponding binding sites may affect the fidelity of the miRNA-mRNA interaction and subsequently alter the risk of cancer development.
METHODS: This study expanded the search for miRNA-related polymorphisms contributing to the etiology of colorectal cancer across the genome using a novel platform, the Axiom miRNA Target Site Genotyping Array (237,858 markers). After quality control, the study included 596 cases and 429 controls from the Molecular Epidemiology of Colorectal Cancer study, a population-based case-control study of colorectal cancer in northern Israel. The association between each marker and colorectal cancer status was examined assuming a log-additive genetic model using logistic regression adjusted for sex, age, and two principal components.
RESULTS: Twenty-three markers had P values less than 5.0E-04, and the most statistically significant association involved rs2985 (chr6:34845648; intronic of UHRF1BP1; OR = 0.66; P = 3.7E-05). Furthermore, this study replicated a previously published risk locus, rs1051690, in the 3'-untranslated region of the insulin receptor gene INSR (OR = 1.38; P = 0.03), with strong evidence of differences in INSR gene expression by genotype.
CONCLUSIONS: This study is the first to examine associations between genetic variation in miRNA target sites and colorectal cancer using a genome-wide approach. Functional studies to identify allele-specific effects on miRNA binding are needed to confirm the regulatory capacity of genetic variation to influence risk of colorectal cancer.
IMPACT: This study demonstrates the potential for an miRNA-targeted genome-wide association study to identify candidate susceptibility loci and prioritize them for functional characterization.

Brower MA, Jones MR, Rotter JI, et al.
Further investigation in europeans of susceptibility variants for polycystic ovary syndrome discovered in genome-wide association studies of Chinese individuals.
J Clin Endocrinol Metab. 2015; 100(1):E182-6 [PubMed] Article available free on PMC after 01/05/2017 Related Publications
CONTEXT: Two genome-wide association studies (GWAS) of polycystic ovary syndrome (PCOS) have identified 11 susceptibility loci in Chinese individuals. Some of the risk loci identified in Chinese cohorts, mostly from the first GWAS, have been replicated in Europeans. Replication of the loci from the second GWAS in European cohorts is necessary to determine whether the same variants confer risk for PCOS in multiple ethnicities.
OBJECTIVE: The objective of the study was to determine the effects of the Chinese GWAS loci in European-origin individuals.
DESIGN: This was a genetic association study.
SETTING: The study was conducted at a tertiary care academic center.
PATIENTS: Eight hundred forty-five European subjects with PCOS and 845 controls participated in the study.
INTERVENTIONS: INTERVENTIONS included blood sampling and genotyping.
MAIN OUTCOME MEASURE: The association between PCOS and 12 independent single-nucleotide polymorphisms mapping to seven of the Chinese GWAS loci in a European cohort was measured.
RESULTS: Variants in DENND1A (P = .0002), THADA (P = .035), FSHR (P = .007), and INSR (P = .046) were associated with PCOS in Europeans. The genetic risk score, generated for each subject based on the total number of risk alleles, was associated with the diagnosis of PCOS (P < .0001) and remained associated (P = .02), even after exclusion of the four variants individually associated with PCOS.
CONCLUSIONS: At least four of the PCOS susceptibility loci identified in the Chinese GWAS are associated with PCOS in Europeans. The overall genetic burden for PCOS, as demonstrated by the risk score, is also associated with the diagnosis of PCOS in Europeans. The PCOS susceptibility loci identified in the Chinese GWAS are thus likely to play an important role in the etiology of PCOS across ethnicities.

Højlund K
Metabolism and insulin signaling in common metabolic disorders and inherited insulin resistance.
Dan Med J. 2014; 61(7):B4890 [PubMed] Related Publications
Type 2 diabetes, obesity and polycystic ovary syndrome (PCOS) are common metabolic disorders which are observed with increasing prevalences, and which are caused by a complex interplay between genetic and environmental factors, including increased calorie intake and physical inactivity. These metabolic disorders are all characterized by reduced plasma adiponectin and insulin resistance in peripheral tissues. Quantitatively skeletal muscle is the major site of insulin resistance. Both low plasma adiponectin and insulin resistance contribute to an increased risk of type 2 diabetes and cardiovascular disease. In several studies, we have investigated insulin action on glucose and lipid metabolism, and at the molecular level, insulin signaling to glucose transport and glycogen synthesis in skeletal muscle from healthy individuals and in obesity, PCOS and type 2 diabetes. Moreover, we have described a novel syndrome characterized by postprandial hyperinsulinemic hypoglycemia and insulin resistance. This syndrome is caused by a mutation in the tyrosine kinase domain of the insulin receptor gene (INSR). We have studied individuals with this mutation as a model of inherited insulin resistance. Type 2 diabetes, obesity and PCOS are characterized by pronounced defects in the insulin-stimulated glucose uptake, in particular glycogen synthesis and to a lesser extent glucose oxidation, and the ability of insulin to suppress lipid oxidation. In inherited insulin resistance, however, only insulin action on glucose uptake and glycogen synthesis is impaired. This suggests that the defects in glucose and lipid oxidation in the common metabolic disorders are secondary to other factors. In young women with PCOS, the degree of insulin resistance was similar to that seen in middle-aged patients with type 2 diabetes. This supports the hypothesis of an unique pathogenesis of insulin resistance in PCOS. Insulin in physiological concentrations stimulates glucose uptake in human skeletal muscle in vivo by activation of the insulin signaling cascade to glucose transport through the enzymes IRS1, PI3K, Akt2, AS160/TBC1D4 and RAC1, and to glycogen synthesis through Akt2, inhibition of GSK3 and activation of glycogen synthase (GS) via dephosphorylation of serine residues in both the NH2-terminal (site 2+2a) and the COOH-terminal end (site 3a+3b). In type 2 diabetes, obesity and PCOS, there is, although with some variation from study to study, defects in insulin signaling through IRS1, PI3K, Akt2 and AS160/TBC1D4, which can explain reduced insulin action on glucose transport. In type 2 diabetes an altered intracellular distribution of SNAP23 and impaired activation of RAC1 also seem to play a role for reduced insulin action on glucose transport. In all common metabolic disorders, we observed an impaired insulin activation of GS, which seems to be caused by attenuated dephosphorylation of GS at site 2+2a, whereas as the inhibition of GSK3 and the dephosphorylation of GS at its target sites, site 3a+3a, appeared to be completely normal. In individuals with inherited insulin resistance, we observed largely the same defects in insulin action on IRS1, PI3K, Akt2 and GS, as well as a normal inhibition of GSK3 and dephosphorylation of GS at site 3a+3b. In these individuals, however, a markedly reduced insulin clearance seems to partially rescue insulin signaling to glucose transport and GS. Adiponectin is thought to improve insulin sensitivity primarily by increasing lipid oxidation through activation of the enzyme AMPK, and possibly via cross-talking of adiponectin with insulin signaling, and hence glucose transport and glycogen synthesis. We demonstrated a strong correlation between plasma adiponectin and insulin action on glucose disposal and glycogen synthesis in obesity, type 2 diabetes and PCOS. In individuals with inherited insulin resistance, plasma adiponectin was normal, but the correlation of adiponectin with insulin-stimulated glucose uptake and glycogen synthesis was at least equally strong. Moreover, we found a correlation between plasma adiponectin and insulin activation of GS. This result is supported by a number of recent studies of animal models and muscle cell lines, which have shown that adiponectin augments insulin action on enzymes in the insulin signaling cascade. In contrast, we observed no differences in the abundance or activity of AMPK in obesity, type 2 diabetes, PCOS or inherited insulin resistance. This indicates that reduced insulin sensitivity in these conditions is not mediated via abnormal AMPK activity. The results from these studies demonstrate that the well-established abnormalities in insulin action on glucose uptake and glycogen synthesis are reflected by defects in insulin signaling to these cellular processes in type 2 diabetes, obesity, and PCOS, and as expected also in inherited insulin resistance caused by a mutation in INSR. In common metabolic disorders, low plasma adiponectin may contribute to insulin resistance and defects in insulin signaling, whereas in inherited insulin resistance a normal plasma adiponectin and reduced insulin clearance could contribute to maintain a sufficient activation of the insulin signaling cascade. The insight gained from these studies have improved our understanding of the molecular mechanisms underlying insulin resistance in skeletal muscle of humans, and can form the basis for further studies, which can lead to the development of treatment that more directly targets insulin resistance, and hence reduce the risk of type 2 diabetes and cardiovascular disease.

Du J, Wang J, Sun X, et al.
Family-based analysis of INSR polymorphisms in Chinese PCOS.
Reprod Biomed Online. 2014; 29(2):239-44 [PubMed] Related Publications
The insulin receptor (INSR), which is an indispensable component of the insulin-signalling pathway, could be a plausible candidate gene for polycystic ovary syndrome (PCOS). This study was designed to determine whether an association exists between three SNP variants (rs3786681, rs17253937 and rs2252673) of the INSR gene and PCOS in Han Chinese. A total of 224 family trios (672 participants in total) were enrolled in this family-based transmission disequilibrium test. Genotypes were obtained by sequencing. A weak association was detected in rs2252673 (P = 0.027), which indicated that INSR may confer an increased susceptibility to PCOS in Chinese. Additionally, the association between INSR gene variants and clinical and metabolic characteristics of women with PCOS was investigated. Carriers of the CG and GG genotypes in women with PCOS were slightly associated with higher cholesterol concentration (t = 2.072, P = 0.048) and lower high-density lipoprotein cholesterol concentration (t = 2.274, P = 0.026). The minor allele conferred increased odds of PCOS independently of body mass index. The present data may provide a basis for further studies of the role of the INSR in the aetiology of PCOS.

Kashima K, Yahata T, Fujita K, Tanaka K
Polycystic ovary syndrome: association of a C/T single nucleotide polymorphism at tyrosine kinase domain of insulin receptor gene with pathogenesis among lean Japanese women.
J Reprod Med. 2013 Nov-Dec; 58(11-12):491-6 [PubMed] Related Publications
OBJECTIVE: To assess whether the insulin receptor (INSR) gene contributes to genetic susceptibility to polycystic ovary syndrome (PCOS) in a Japanese population.
STUDY DESIGN: We ex-amined the frequency of the His 1058 C/T single nucleotide polymorphism (SNP) found in exon 17 of the INSR gene in 61 Japanese PCOS patients and 99 Japanese healthy controls. In addition, we analyzed the association between the genotype of this SNP and the clinical phenotypes.
RESULTS: The frequency of the C/C genotype was not significantly different between all PCOS patients (47.5%) and controls (35.4%). However, among the lean cases (body mass index < or = 20 kg/m2) the frequency of the C/C genotype was significantly increased (p < 0.05) in PCOS patients (65.0%) as compared with controls (36.6%).
CONCLUSION: We concluded that the His 1058 C/T polymorphism at the tyrosine kinase domain of the INSR gene had a relationship to the pathogenesis of lean PCOS patients in a Japanese population.

Gurung B, Muhammad AB, Hua X
Menin is required for optimal processing of the microRNA let-7a.
J Biol Chem. 2014; 289(14):9902-8 [PubMed] Article available free on PMC after 01/05/2017 Related Publications
Multiple endocrine neoplasia type I (MEN1) is an inherited syndrome that includes susceptibility to pancreatic islet hyperplasia. This syndrome results from mutations in the MEN1 gene, which encodes menin protein. Menin interacts with several transcription factors, including JunD, and inhibits their activities. However, the precise mechanism by which menin suppresses gene expression is not well understood. Here, we show that menin interacts with arsenite-resistant protein 2 (ARS2), a component of the nuclear RNA CAP-binding complex that is crucial for biogenesis of certain miRNAs including let-7a. The levels of primary-let-7a (pri-let-7a) are not affected by menin; however, the levels of mature let-7a are substantially decreased upon Men1 excision. Let-7a targets, including Insr and Irs2, pro-proliferative genes that are crucial for insulin-mediated signaling, are up-regulated in Men1-excised cells. Inhibition of let-7a using anti-miRNA in wild type cells is sufficient to enhance the expression of insulin receptor substrate 2 (IRS2) to levels observed in Men1-excised cells. Depletion of menin does not affect the expression of Drosha and CBP80, but substantially impairs the processing of pri-miRNA to pre-miRNA. Ars2 knockdown decreased let-7a processing in menin-expressing cells but had little impact on let-7a levels in menin-excised cells. As IRS2 is known to mediate insulin signaling and insulin/mitogen-induced cell proliferation, these findings collectively unravel a novel mechanism whereby menin suppresses cell proliferation, at least partly by promoting the processing of certain miRNAs, including let-7a, leading to suppression of Irs2 expression and insulin signaling.

Singh P, Alex JM, Bast F
Insulin receptor (IR) and insulin-like growth factor receptor 1 (IGF-1R) signaling systems: novel treatment strategies for cancer.
Med Oncol. 2014; 31(1):805 [PubMed] Related Publications
Insulin and insulin-like growth factor (IGF) signaling system, commonly known for fine-tuning numerous biological processes, has lately made its mark as a much sought-after therapeutic targets for diabetes and cancer. These receptors make an attractive anticancer target owing to their overexpression in variety of cancer especially in prostate and breast cancer. Inhibitors of IGF signaling were subjected to clinical cancer trials with the main objective to confirm the effectiveness of these receptors as a therapeutic target. However, the results that these trials produced proved to be disappointing as the role played by the cross talk between IGF and insulin receptor (IR) signaling pathways at the receptor level or at downstream signaling level became more lucid. Therapeutic strategy for IGF-1R and IR inhibition mainly encompasses three main approaches namely receptor blockade with monoclonal antibodies, tyrosine kinase inhibition (ATP antagonist and non-ATP antagonist), and ligand neutralization via monoclonal antibodies targeted to ligand or recombinant IGF-binding proteins. Other drug-discovery approaches are employed to target IGF-1R, and IR includes antisense oligonucleotides and recombinant IGF-binding proteins. However, therapies with monoclonal antibodies and tyrosine kinase inhibition targeting the IGF-1R are not evidenced to be satisfactory as expected. Factors that are duly held responsible for the unsuccessfulness of these therapies include (a) the existence of the IR isoform A overexpressed on a variety of cancers, enhancing the mitogenic signals to the nucleus leading to the endorsement of cell growth, (b) IGF-1R and IR that form hybrid receptors sensitive to the stimulation of all three IGF axis ligands, and (c) IGF-1R and IR that also have the potential to form hybrid receptors with other tyrosine kinase to potentiate the cellular transformation, tumorigenesis, and tumor vascularization. This mini review is a concerted effort to explore and fathom the well-recognized roles of the IRA signaling system in human cancer phenotype and the main strategies that have been so far evaluated to target the IR and IGF-1R.

Ellis BC, Graham LD, Molloy PL
CRNDE, a long non-coding RNA responsive to insulin/IGF signaling, regulates genes involved in central metabolism.
Biochim Biophys Acta. 2014; 1843(2):372-86 [PubMed] Related Publications
Colorectal neoplasia differentially expressed (CRNDE) is a novel gene that is activated early in colorectal cancer but whose regulation and functions are unknown. CRNDE transcripts are recognized as long non-coding RNAs (lncRNAs), which potentially interact with chromatin-modifying complexes to regulate gene expression via epigenetic changes. Complex alternative splicing results in numerous transcripts from this gene, and we have identified novel transcripts containing a highly-conserved sequence within intron 4 ("gVC-In4"). In colorectal cancer cells, we demonstrate that treatment with insulin and insulin-like growth factors (IGF) repressed CRNDE nuclear transcripts, including those encompassing gVC-In4. These repressive effects were negated by use of inhibitors against either the PI3K/Akt/mTOR pathway or Raf/MAPK pathway, suggesting CRNDE is a downstream target of both signaling cascades. Expression array analyses revealed that siRNA-mediated knockdown of gVC-In4 transcripts affected the expression of many genes, which showed correlation with insulin/IGF signaling pathway components and responses, including glucose and lipid metabolism. Some of the genes are identical to those affected by insulin treatment in the same cell line. The results suggest that CRNDE expression promotes the metabolic changes by which cancer cells switch to aerobic glycolysis (Warburg effect). This is the first report of a lncRNA regulated by insulin/IGFs, and our findings indicate a role for CRNDE nuclear transcripts in regulating cellular metabolism which may correlate with their upregulation in colorectal cancer.

Karimi K, Mahmoudi T, Karimi N, et al.
Is there an association between variants in candidate insulin pathway genes IGF-I, IGFBP-3, INSR, and IRS2 and risk of colorectal cancer in the Iranian population?
Asian Pac J Cancer Prev. 2013; 14(9):5011-6 [PubMed] Related Publications
BACKGROUND: Several epidemiological studies have shown associations between colorectal cancer (CRC) risk and type 2 diabetes and obesity. Any effects would be expected to be mediated through the insulin pathway. Therefore it is possible that variants of genes encoding components of the insulin pathway play roles in CRC susceptibility. In this study, we hypothesized that polymorphisms in the genes involving the insulin pathway are associated with risk of CRC.
MATERIALS AND METHODS: The associations of four single nucleotide polymorphisms (SNPs) in IGF-I (rs6214), IGFBP-3 (rs3110697), INSR (rs1052371), and IRS2 (rs2289046) genes with the risk of CRC were evaluated using a case-control design with 167 CRC cases and 277 controls by the PCR-RFLP method.
RESULTS: Overall, we observed no significant difference in genotype and allele frequencies between the cases and controls for the IGF-I, IGFBP-3, INSR, IRS2 gene variants and CRC before or after adjusting for confounders (age, BMI, sex, and smoking status). However, we observed that the IRS2 (rs2289046) GG genotype compared with AA+AG genotypes has a protective effect for CRC in normal weight subjects (p=0.035, OR=0.259, 95%CI= 0.074-0.907).
CONCLUSIONS: These findings do not support plausible associations between polymorphic variations in IGF-I, IGFBP-3, INSR, IRS2 genes and risk of CRC. However, the evidence for a link between the IRS2 (rs2289046) variant and risk of CRC dependent on the BMI of the subjects, requires confirmation in subsequent studies with greater sample size.

Beadling C, Patterson J, Justusson E, et al.
Gene expression of the IGF pathway family distinguishes subsets of gastrointestinal stromal tumors wild type for KIT and PDGFRA.
Cancer Med. 2013; 2(1):21-31 [PubMed] Article available free on PMC after 01/05/2017 Related Publications
Gastrointestinal stromal tumors (GISTs) arise from the interstitial cells of Cajal (ICCs) and are the most common mesenchymal neoplasm of the gastrointestinal tract. While the majority of GISTs harbor activating mutations in either the v-kit Hardy-Zuckerman feline sarcoma viral oncogene homolog (KIT) or platelet-derived growth factor receptor alpha (PDGFRA) tyrosine kinases, approximately 10-15% of adult GISTs and 85% of pediatric GISTs lack such mutations. These "wild-type" GISTs have been reported to express high levels of the insulin-like growth factor 1 receptor (IGF1R), and IGF1R-targeted therapy of wild-type GISTs is being evaluated in clinical trials. However, it is not clear that all wild-type GISTs express IGF1R, because studies to date have predominantly focused on a particular subtype of gastric wild-type GIST that is deficient in the mitochondrial succinate dehydrogenase (SDH) complex. This study of a series of 136 GISTs, including 72 wild-type specimens, was therefore undertaken to further characterize wild-type GIST subtypes based on the relative expression of transcripts encoding IGF1R. Additional transcripts relevant to GIST biology were also evaluated, including members of the IGF-signaling pathway (IGF1, IGF2, and insulin receptor [INSR]), neural markers (CDH2[CDH: Cadherin], neurofilament, light polypeptide, LHX2 [LHX: LIM homeobox], and KIRREL3 [KIRREL: kin of IRRE like]), KIT, PDGFRA, CD34, and HIF1A. Succinate dehydrogenase complex, subunit B protein expression was also assessed as a measure of SDH complex integrity. In addition to the previously described SDH-deficient, IGF1R(high) wild-type GISTs, other SDH-intact wild-type subpopulations were defined by high relative expression of IGF1R, neural markers, IGF1 and INSR, or low IGF1R coupled with high IGF2. These results underscore the complexity and heterogeneity of wild-type GISTs that will need to be factored into molecularly-targeted therapeutic strategies.

Mäki-Nevala S, Kaur Sarhadi V, Tuononen K, et al.
Mutated ephrin receptor genes in non-small cell lung carcinoma and their occurrence with driver mutations-targeted resequencing study on formalin-fixed, paraffin-embedded tumor material of 81 patients.
Genes Chromosomes Cancer. 2013; 52(12):1141-9 [PubMed] Related Publications
Non-small cell lung carcinoma (NSCLC) is the most common subtype of lung cancer. The oncogenic potential of receptor tyrosine kinases (RTKs) is widely known and they are potential targets for tailored therapy. Ephrin receptors (Ephs) form the largest group of RTKs. Nevertheless, Ephs are not widely studied in NSCLC so far. The aim of our study was to investigate novel mutations of Eph genes (EPHA1-8, EPHB1-4, EPHB6) and their association with clinically relevant mutations in BRAF, EML4-ALK, EGFR, INSR, KDR, KRAS, MET, PDGFRA, PDGFRB, PIK3, PTEN, RET, and TP53 in NSCLC patients. Targeted resequencing was conducted on 81 formalin-fixed, paraffin-embedded NSCLC tumor specimens. We analyzed missense and nonsense mutations harbored in the coding regions of the selected genes. We found 18 novel mutations of Ephs in 20% (16 of 81) of the patients. Nearly half of these mutations occurred in the protein kinase domain. The mutations were not mutually exclusive with other clinically relevant mutations. Our study shows that Ephs are frequently mutated in NSCLC patients, and occur together with other known mutations relevant to the pathogenicity of NSCLC.

Louwers YV, Stolk L, Uitterlinden AG, Laven JS
Cross-ethnic meta-analysis of genetic variants for polycystic ovary syndrome.
J Clin Endocrinol Metab. 2013; 98(12):E2006-12 [PubMed] Related Publications
CONTEXT: Genome-wide association studies (GWAS) have revealed new susceptibility loci for Chinese patients with polycystic ovary syndrome (PCOS). Because ethnic background adds to phenotypic diversities in PCOS, it seems plausible that genetic variants associated with PCOS act differently in various ethnic populations.
OBJECTIVE: We studied cross-ethnic effects of Chinese PCOS loci (ie, LHCGR, THADA, DENND1A, FSHR, c9orf3, YAP1, RAB5B/SUOX, HMGA2, TOX3, INSR, SUMO1P1) in patients of Northern European descent.
DESIGN: This study was a genetic association study conducted at an University Medical Center.
PATIENTS: Association was studied in 703 Dutch PCOS patients and 2164 Dutch controls. To assess the cross-ethnic effect, we performed a meta-analysis of the Dutch data combined with results of previously published studies in PCOS patients from China (n = 2254) and the United States (n = 2618). Adjusted for multiple testing, a P value <3.1 × 10⁻³ was considered statistically significant.
RESULTS: Meta-analysis of the Chinese, US, and Dutch data resulted in 12 significant variants mapping to the YAP1 (P value = 1.0 × 10⁻⁹), RAB5B/SUOX (P value = 3.8 × 10⁻¹¹), LHCGR (P value = 4.1 × 10⁻⁴), THADA (P value = 2.2 × 10⁻⁴ and P value = 1.3 × 10⁻³), DENND1A (P value = 2.3 × 10⁻³ and P value = 2.5 × 10⁻³), FSHR (P value = 3.8 × 10⁻⁵ and P value = 3.6 × 10⁻⁴), c9orf3 (P value = 2.0 × 10⁻⁶ and P value = 9.2 × 10⁻⁶), SUMO1P1 (P value = 2.3 × 10⁻³) loci with odds ratios ranging from 1.19 to 1.45 and 0.79 to 0.87.
CONCLUSIONS: Overall, we observed for 12 of 17 genetic variants mapping to the Chinese PCOS loci similar effect size and identical direction in PCOS patients from Northern European ancestry, indicating a common genetic risk profile for PCOS across populations. Therefore, it is expected that large GWAS in PCOS patients from Northern European ancestry will partly identify similar loci as the GWAS in Chinese PCOS patients.

Corominas-Faja B, Cufí S, Oliveras-Ferraros C, et al.
Nuclear reprogramming of luminal-like breast cancer cells generates Sox2-overexpressing cancer stem-like cellular states harboring transcriptional activation of the mTOR pathway.
Cell Cycle. 2013; 12(18):3109-24 [PubMed] Article available free on PMC after 01/05/2017 Related Publications
Energy metabolism plasticity enables stemness programs during the reprogramming of somatic cells to an induced pluripotent stem cell (iPSC) state. This relationship may introduce a new era in the understanding of Warburg's theory on the metabolic origin of cancer at the level of cancer stem cells (CSCs). Here, we used Yamanaka's stem cell technology in an attempt to create stable CSC research lines in which to dissect the transcriptional control of mTOR--the master switch of cellular catabolism and anabolism--in CSC-like states. The rare colonies with iPSC-like morphology, obtained following the viral transduction of the Oct4, Sox2, Klf4, and c-Myc (OSKM) stemness factors into MCF-7 luminal-like breast cancer cells (MCF-7/Rep), demonstrated an intermediate state between cancer cells and bona fide iPSCs. MCF-7/Rep cells notably overexpressed SOX2 and stage-specific embryonic antigen (SSEA)-4 proteins; however, other stemness-related markers (OCT4, NANOG, SSEA-1, TRA-1-60, and TRA-1-81) were found at low to moderate levels. The transcriptional analyses of OSKM factors confirmed the strong but unique reactivation of the endogenous Sox2 stemness gene accompanied by the silencing of the exogenous Sox2 transgene in MCF-7/Rep cells. Some but not all MCF-7/Rep cells acquired strong alkaline phosphatase (AP) activity compared with MCF-7 parental cells. SOX2-overexpressing MCF-7/Rep cells contained drastically higher percentages of CD44(+) and ALDEFLUOR-stained ALDH(bright) cells than MCF-7 parental cells. The overlap between differentially expressed mTOR signaling-related genes in 3 different SOX2-overexpressing CSC-like cell lines revealed a notable downregulation of 3 genes, PRKAA1 (which codes for the catalytic α 1 subunit of AMPK), DDIT4/REDD1 (a stress response gene that operates as a negative regulator of mTOR), and DEPTOR (a naturally occurring endogenous inhibitor of mTOR activity). The insulin-receptor gene (INSR) was differentially upregulated in MCF-7/Rep cells. Consistent with the downregulation of AMPK expression, immunoblotting procedures confirmed upregulation of p70S6K and increased phosphorylation of mTOR in Sox2-overexpressing CSC-like cell populations. Using an in vitro model of the de novo generation of CSC-like states through the nuclear reprogramming of an established breast cancer cell line, we reveal that the transcriptional suppression of mTOR repressors is an intrinsic process occurring during the acquisition of CSC-like properties by differentiated populations of luminal-like breast cancer cells. This approach may provide a new path for obtaining information about preventing the appearance of CSCs through the modulation of the AMPK/mTOR pathway.

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