IRS2

Gene Summary

Gene:IRS2; insulin receptor substrate 2
Aliases: IRS-2
Location:13q34
Summary:This gene encodes the insulin receptor substrate 2, a cytoplasmic signaling molecule that mediates effects of insulin, insulin-like growth factor 1, and other cytokines by acting as a molecular adaptor between diverse receptor tyrosine kinases and downstream effectors. The product of this gene is phosphorylated by the insulin receptor tyrosine kinase upon receptor stimulation, as well as by an interleukin 4 receptor-associated kinase in response to IL4 treatment. [provided by RefSeq, Jul 2008]
Databases:OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:insulin receptor substrate 2
Source:NCBIAccessed: 31 August, 2019

Ontology:

What does this gene/protein do?
Show (33)
Pathways:What pathways are this gene/protein implicaed in?
Show (3)

Cancer Overview

Research Indicators

Publications Per Year (1994-2019)
Graph generated 31 August 2019 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.

  • Polymorphism
  • Insulin Receptor Substrate Proteins
  • Transcription Factor DP1
  • Phosphorylation
  • Cell Movement
  • Colorectal Cancer
  • Insulin
  • Transfection
  • Cell Proliferation
  • Xenograft Models
  • Case-Control Studies
  • Cancer Gene Expression Regulation
  • Proto-Oncogene Proteins
  • Genetic Predisposition
  • beta Catenin
  • Genotype
  • Thiazolidinediones
  • Southwestern United States
  • Somatomedins
  • Intracellular Signaling Peptides and Proteins
  • Phosphatidylinositol 3-Kinases
  • Phosphoproteins
  • IGF1R
  • Sucrose
  • Polycystic Ovary Syndrome
  • Mutation
  • Receptor, Insulin
  • Genetic Variation
  • AKT1
  • Insulin-Like Growth Factor I
  • Insulin-Like Growth Factor Binding Protein 3
  • src Homology Domains
  • Risk Factors
  • Chromosome 13
  • Signal Transduction
  • Western Blotting
  • Single Nucleotide Polymorphism
  • MicroRNAs
  • Prostate Cancer
  • Breast Cancer
Tag cloud generated 31 August, 2019 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: IRS2 (cancer-related)

He T, Liu Y, Zhao S, et al.
Comprehensive assessment the expression of core elements related to IGFIR/PI3K pathway in granulosa cells of women with polycystic ovary syndrome.
Eur J Obstet Gynecol Reprod Biol. 2019; 233:134-140 [PubMed] Related Publications
OBJECTIVE: Polycystic ovary syndrome (PCOS) is the most common multisystem endocrinopathy in women, characterized by chronic hyperandrogenism, ovulatory dysfunction, and polycystic ovaries. But its etiology remains elusive. A plethora of information suggests phosphatidylinositol-3-kinase (PI3K) pathway is key to the pathogenesis of PCOS but little is known about the expression pattern and possible role of insulin like growth factor 1 receptor (IGFIR)/PI3K pathway in PCOS. The goal of this study was to determine whether the core elements of the IGF1R/PI3K pathway were differentially expressed in GCs isolated from PCOS.
STUDY DESIGN: Western blot (WB) and reverse transcription-polymerase chain reaction (RT-PCR) for IGF1R, insulin receptor substrate 1 (IRS1), insulin receptor substrate 2 (IRS2) and phosphatase and tensin homolog (PTEN) related to IGFIR/PI3K pathway were performed in GCs isolated from 60 PCOS patients and 60 controls.
RESULTS: Compared to controls, body mass index (BMI), the levels of fasting plasma glucose (FPG), fasting insulin (FINS), anti-Mullerian hormone (AMH), testosterone (T), luteotropic hormone (LH), homeostasis model assessment of insulin resistance (HOMA-IR), antral follicle count (AFC) were markedly elevated while follicle stimulating hormone (FSH) decreased (p < 0.05). Furthermore, at both mRNA and protein levels, the expression of IGF1R, IRS1, IRS2 were significantly increased whereas PTEN was dramatically decreased in PCOS patients (p <  0.05).
CONCLUSION: Our findings indicate that IGFIR/PI3K pathway is differently expressed in PCOS GCs compared with controls, with IGFIR, IRS1, IRS2 significantly increased while PTEN decreased. Thus, our study probably provides new evidences about the pathogenesis of PCOS in term of molecular mechanism.

Zhao J, Li Z, Chen Y, et al.
MicroRNA‑766 inhibits papillary thyroid cancer progression by directly targeting insulin receptor substrate 2 and regulating the PI3K/Akt pathway.
Int J Oncol. 2019; 54(1):315-325 [PubMed] Related Publications
MicroRNAs (miRNAs/miRs) are widely dysregulated in papillary thyroid cancer (PTC). Dysregulated miRNAs, together with their target genes, comprise a complex network that has been implicated in the regulation of PTC pathogenesis. Further knowledge of the functional roles of aberrantly expressed miRNAs in PTC, and the underlying molecular mechanisms, may assist in the identification of novel therapeutic targets. miR‑766 has been well studied in human cancer; however, the expression status, specific roles and regulatory mechanisms of miR‑766 in PTC remain unclear. The present study aimed to detect miR‑766 expression in PTC tissues and cell lines, to explore the biological roles of miR‑766 in the malignant biological behaviors of PTC cells, and to determine the underlying mechanism of action of miR‑766 in PTC cells. The results revealed that miR‑766 was downregulated in PTC tissues and cell lines, and its downregulation was strongly associated with TNM stage and lymph node metastasis. Overexpression of miR‑766 inhibited PTC cell proliferation, colony formation, migration and invasion, promoted cell apoptosis and reduced tumor growth in vivo. Mechanistically, insulin receptor substrate 2 (IRS2) was identified as a direct target of miR‑766 in PTC cells. IRS2 was upregulated in PTC tissues, and this was inversely correlated with miR‑766 expression. Inhibition of IRS2 simulated the tumor suppressor activity of miR‑766 in PTC cells. Restoration of IRS2 expression negated the tumor‑suppressing effects of miR‑766 overexpression on PTC cells. Notably, miR‑766 directly targeted IRS2 to inhibit activation of the phosphoinositide 3‑kinase (PI3K)/protein kinase B (Akt) pathway in PTC cells in vitro and in vivo. Overall, these findings indicated that miR‑766 may inhibit the malignant biological behaviors of PTC cells by directly targeting IRS2 and regulating the PI3K/Akt pathway, thus suggesting that this miRNA may be a promising therapeutic target for PTC.

Mercado-Matos J, Janusis J, Zhu S, et al.
Identification of a Novel Invasion-Promoting Region in Insulin Receptor Substrate 2.
Mol Cell Biol. 2018; 38(14) [PubMed] Free Access to Full Article Related Publications
Although the insulin receptor substrate (IRS) proteins IRS1 and IRS2 share considerable homology and activate common signaling pathways, their contributions to breast cancer are distinct. IRS1 has been implicated in the proliferation and survival of breast tumor cells. In contrast, IRS2 facilitates glycolysis, invasion, and metastasis. To determine the mechanistic basis for IRS2-dependent functions, we investigated unique structural features of IRS2 that are required for invasion. Our studies revealed that the ability of IRS2 to promote invasion is dependent upon upstream insulin-like growth factor 1 receptor (IGF-1R)/insulin receptor (IR) activation and the recruitment and activation of phosphatidylinositol 3-kinase (PI3K), functions shared with IRS1. In addition, a 174-amino-acid region in the IRS2 C-terminal tail, which is not conserved in IRS1, is also required for IRS2-mediated invasion. Importantly, this "invasion (INV) region" is sufficient to confer invasion-promoting ability when swapped into IRS1. However, the INV region is not required for the IRS2-dependent regulation of glucose uptake. Bone morphogenetic protein 2-inducible kinase (BMP2K) binds to the INV region and contributes to IRS2-dependent invasion. Taken together, our data advance the mechanistic understanding of how IRS2 regulates invasion and reveal that IRS2 functions important for cancer can be independently targeted without interfering with the metabolic activities of this adaptor protein.

Semmlinger A, von Schoenfeldt V, Wolf V, et al.
EP3 (prostaglandin E2 receptor 3) expression is a prognostic factor for progression-free and overall survival in sporadic breast cancer.
BMC Cancer. 2018; 18(1):431 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: In various cancers, overexpression of cyclooxygenase (COX)-2 and elevated prostaglandin (PG) E2 synthesis have been associated with tumor development and progression. The potential of COX-2 inhibitors in cancer prevention and treatment has been shown repeatedly; however, their clinical use is limited due to toxicity. PGE2 signals via EP receptors 1-4, whose functions are analyzed in current research in search for targeted anti-PG therapies. EP2 and EP4 rather promote tumorigenesis, while the role of EP3, especially in breast cancer, is not yet clear and both pro- and anti-tumorigenic effects have been described. Our study evaluates EP3 receptor expression in sporadic breast cancer and its association with clinicopathological parameters, progression-free and overall survival.
METHODS: Two hundred eighty-nine sporadic breast cancer samples without primary distant metastasis were immunohistochemically analyzed for EP3 receptor expression. Tissue was stained with primary anti-EP3-antibodies. Immunoreactivity was quantified by the immunoreactivity-score (IRS); samples with an IRS ≥ 2 scored as EP3 positive. Chi-squared and Mann-Whitney-U test were used for comparison of data; Kaplan-Meier estimates and Cox-regression were used for survival analyses.
RESULTS: EP3 receptor was expressed in 205 of 289 samples analyzed (70.9%). EP3 receptor expression was not associated with clinicopathological parameters (e. g. tumor size, hormone receptors, lymph node status). Kaplan-Meier estimates showed a significant association of EP3 positivity with improved progression-free survival (p = 0.002) and improved overall survival (p = 0.001) after up to 10 years. Cox regression analysis confirmed EP3 positivity as a significant prognostic factor even when other known prognosticators were accounted for.
CONCLUSIONS: In sporadic breast cancer, EP3 receptor expression is not significantly associated with clinicopathological parameters but is a significant prognostic factor for improved progression-free and overall survival. However, the functional aspects of EP3 receptor in breast cancer and the way how EP3 may oppose the pro-tumorigenic effects of PGE2 elevation and COX-2 overexpression are not fully understood so far. Further studies aiming at identification of the factors regulated by EP3 are necessary to evaluate the possibility of targeting EP3 in future anti-tumor therapy in breast cancer.

Xu H, Lee MS, Tsai PY, et al.
Ablation of insulin receptor substrates 1 and 2 suppresses
Proc Natl Acad Sci U S A. 2018; 115(16):4228-4233 [PubMed] Free Access to Full Article Related Publications
Non-small-cell lung cancer (NSCLC) is a leading cause of cancer death worldwide, with 25% of cases harboring oncogenic Kirsten rat sarcoma (

Jeong SH, Kim HB, Kim MC, et al.
Hippo-mediated suppression of IRS2/AKT signaling prevents hepatic steatosis and liver cancer.
J Clin Invest. 2018; 128(3):1010-1025 [PubMed] Free Access to Full Article Related Publications
Nonalcoholic fatty liver disease (NAFLD) is a major risk factor for liver cancer; therefore, its prevention is an important clinical goal. Ablation of phosphatase and tensin homolog (PTEN) or the protein kinase Hippo signaling pathway induces liver cancer via activation of AKT or the transcriptional regulators YAP/TAZ, respectively; however, the potential for crosstalk between the PTEN/AKT and Hippo/YAP/TAZ pathways in liver tumorigenesis has thus far remained unclear. Here, we have shown that deletion of both PTEN and SAV1 in the liver accelerates the development of NAFLD and liver cancer in mice. At the molecular level, activation of YAP/TAZ in the liver of Pten-/- Sav1-/- mice amplified AKT signaling through the upregulation of insulin receptor substrate 2 (IRS2) expression. Both ablation of YAP/TAZ and activation of the Hippo pathway could rescue these phenotypes. A high level of YAP/ TAZ expression was associated with a high level of IRS2 expression in human hepatocellular carcinoma (HCC). Moreover, treatment with the AKT inhibitor MK-2206 or knockout of IRS2 by AAV-Cas9 successfully repressed liver tumorigenesis in Pten-/- Sav1-/- mice. Thus, our findings suggest that Hippo signaling interacts with AKT signaling by regulating IRS2 expression to prevent NAFLD and liver cancer progression and provide evidence that impaired crosstalk between these 2 pathways accelerates NAFLD and liver cancer.

Conti DV, Wang K, Sheng X, et al.
Two Novel Susceptibility Loci for Prostate Cancer in Men of African Ancestry.
J Natl Cancer Inst. 2017; 109(8) [PubMed] Free Access to Full Article Related Publications
Prostate cancer incidence is 1.6-fold higher in African Americans than in other populations. The risk factors that drive this disparity are unknown and potentially consist of social, environmental, and genetic influences. To investigate the genetic basis of prostate cancer in men of African ancestry, we performed a genome-wide association meta-analysis using two-sided statistical tests in 10 202 case subjects and 10 810 control subjects. We identified novel signals on chromosomes 13q34 and 22q12, with the risk-associated alleles found only in men of African ancestry (13q34: rs75823044, risk allele frequency = 2.2%, odds ratio [OR] = 1.55, 95% confidence interval [CI] = 1.37 to 1.76, P = 6.10 × 10-12; 22q12.1: rs78554043, risk allele frequency = 1.5%, OR = 1.62, 95% CI = 1.39 to 1.89, P = 7.50 × 10-10). At 13q34, the signal is located 5' of the gene IRS2 and 3' of a long noncoding RNA, while at 22q12 the candidate functional allele is a missense variant in the CHEK2 gene. These findings provide further support for the role of ancestry-specific germline variation in contributing to population differences in prostate cancer risk.

Simoneau E, Chicoine J, Negi S, et al.
Next generation sequencing of progressive colorectal liver metastases after portal vein embolization.
Clin Exp Metastasis. 2017; 34(5):351-361 [PubMed] Related Publications
Portal vein embolization (PVE) can be required to stimulate liver regeneration before hepatectomy for colorectal liver metastasis (CRCLM), however PVE may also trigger CRCLM progression in patients initially exhibiting chemotherapy response. Using RNA-seq, we aimed to determine the molecular networks involved in metastatic progression in this context. A prospective study including all CRCLM patients undergoing PVE prior to hepatectomy was conducted. Paired biopsies of metastatic lesions were obtained prior to and after PVE and total RNA was isolated and used to prepare Illumina rRNA-depleted TruSeq stranded cDNA libraries for HiSeq 100 bp paired-end sequencing. Patients were classified with progression of disease (PD
RESULTS: Twenty patients were included, 13 (65.0%) in the PD
CONCLUSION: Differentially expressed genes and pathways with known links to cancer and metastasis were identified post-PVE in patients with disease progression. Highlighting these molecular changes is a crucial first step towards development of targeted therapeutic strategies that may mitigate the effects of PVE on tumor growth.

Thangavelu M, Godla UR, Paul Solomon FD, Maddaly R
Single-nucleotide polymorphism of INS, INSR, IRS1, IRS2, PPAR-G and CAPN10 genes in the pathogenesis of polycystic ovary syndrome.
J Genet. 2017; 96(1):87-96 [PubMed] Related Publications
Polycystic ovary syndrome (PCOS) is the most common and a complex female endocrine disorder, and is one of the leading cause of female infertility. Here, we aimed to investigate the association of single-nucleotide polymorphism of INS, INSR, IRS1, IRS2, PPAR-G and CAPN10 gene in the pathogenesis of PCOS. A hospital-based, observational case-control study was carried on 169 PCOS and 169 control women in the southern region of India. Genotype was carried out by real-time polymerase chain reaction. A chi-square (χ

Du Z, Sha X
Demethoxycurcumin inhibited human epithelia ovarian cancer cells' growth via up-regulating miR-551a.
Tumour Biol. 2017; 39(3):1010428317694302 [PubMed] Related Publications
Curcumin is a natural agent that has ability to dampen tumor cells' growth. However, the natural form of curcumin is prone to degrade and unstable in vitro. Here, we demonstrated that demethoxycurcumin (a curcumin-related demethoxy compound) could inhibit cell proliferation and induce apoptosis of ovarian cancer cells. Moreover, IRS2/PI3K/Akt axis was inactivated in cells treated with demethoxycurcumin. Quantitative real-time reverse transcription polymerase chain reaction demonstrated that miR-551a was down-regulated in ovarian cancer tissues and ovarian cancer cell lines. Over-expression of miR-551a inhibited cell proliferation and induced apoptosis of ovarian cancer cells, whereas down-regulation of miR-551a exerted the opposite function. Luciferase assays confirmed that there was a binding site of miR-551a in IRS2, and we found that miR-551a exerted tumor-suppressive function by targeting IRS2 in ovarian cancer cells. Remarkably, miR-551a was up-regulated in the cells treated with demethoxycurcumin, and demethoxycurcumin suppressed IRS2 by restoration of miR-551a. In conclusion, demethoxycurcumin hindered ovarian cancer cells' malignant progress via up-regulating miR-551a.

Baocheng W, Zhao Y, Meng W, et al.
Polymorphisms of insulin receptor substrate 2 are putative biomarkers for pediatric medulloblastoma: considering the genetic susceptibility and pathological diagnoses.
Nagoya J Med Sci. 2017; 79(1):47-54 [PubMed] Free Access to Full Article Related Publications
Molecular profiling subgrouped medulloblastoma (MB) into four subtypes featured by distinct footprints. However, germline studies on genetic susceptibility in Chinese population have not been reported. To investigate the correlation of polymorphisms involved in the AKT signaling pathway with clinicopathological parameters in pediatric MB, and their contribution to the clinical outcome, we performed a case-controlled cohort consisting of 48 patients with pediatric MB and 190 healthy controls from Han population. Significant association in rs7987237 of insulin receptor substrate 2 (IRS2) was identified as risk allele/genotype between MB patients and control group (

Keum N, Yuan C, Nishihara R, et al.
Dietary glycemic and insulin scores and colorectal cancer survival by tumor molecular biomarkers.
Int J Cancer. 2017; 140(12):2648-2656 [PubMed] Free Access to Full Article Related Publications
Accumulating evidence suggests that post-diagnostic insulin levels may influence colorectal cancer (CRC) survival. Yet, no previous study has examined CRC survival in relation to a post-diagnostic diet rich in foods that increase post-prandial insulin levels. We hypothesized that glycemic and insulin scores (index or load; derived from food frequency questionnaire data) may be associated with survival from specific CRC subtypes sensitive to the insulin signaling pathway. We prospectively followed 1,160 CRC patients from the Nurses' Health Study (1980-2012) and Health Professionals Follow-Up Study (1986-2012), resulting in 266 CRC deaths in 10,235 person-years. CRC subtypes were defined by seven tumor biomarkers (KRAS, BRAF, PIK3CA mutations, and IRS1, IRS2, FASN and CTNNB1 expression) implicated in the insulin signaling pathway. For overall CRC and each subtype, hazard ratio (HR) and 95% confidence interval (95% CI) for an increase of one standard deviation in each of glycemic and insulin scores were estimated using time-dependent Cox proportional hazards model. We found that insulin scores, but not glycemic scores, were positively associated with CRC mortality (HR = 1.19, 95% CI = 1.02-1.38 for index; HR = 1.23, 95% CI = 1.04-1.47 for load). The significant positive associations appeared more pronounced among PIK3CA wild-type cases and FASN-negative cases, with HR ranging from 1.36 to 1.60 across insulin scores. However, we did not observe statistically significant interactions of insulin scores with PIK3CA, FASN, or any other tumor marker (p interaction > 0.12). While additional studies are needed for definitive evidence, a high-insulinogenic diet after CRC diagnosis may contribute to worse CRC survival.

Yin J, Zhang Z, Zheng H, Xu L
IRS-2 rs1805097 polymorphism is associated with the decreased risk of colorectal cancer.
Oncotarget. 2017; 8(15):25107-25114 [PubMed] Free Access to Full Article Related Publications
Recent studies explored the association between insulin receptor substrate-2 (IRS-2) gene rs1805097 polymorphism and colorectal cancer (CRC) with contradictory findings. Therefore, we conducted a comprehensive meta-analysis by searching the databases of PubMed and Embase. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by using fixed-effect or random-effect models. A total of 5 citations containing 6 case-control studies involving 4,333 cases and 5,333 controls were included. Our data indicated that IRS-2 rs1805097 polymorphism was associated with decreased risk of CRC. Stratification analysis of ethnicity found that rs1805097 polymorphism decreased the risk of CRC among Americans. Stratification analysis of cancer type suggested that this polymorphism decreased the risk of colon cancer. In summary, this meta-analysis indicates that IRS-2 gene rs1805097 polymorphism plays an important role in the pathogenesis of CRC.

Tan Y, Sementino E, Xu J, et al.
The homeoprotein Dlx5 drives murine T-cell lymphomagenesis by directly transactivating Notch and upregulating Akt signaling.
Oncotarget. 2017; 8(9):14941-14956 [PubMed] Free Access to Full Article Related Publications
Homeobox genes play a critical role in embryonic development, but they have also been implicated in cancer through mechanisms that are largely unknown. While not expressed during normal T-cell development, homeobox transcription factor genes can be reactivated via recurrent chromosomal rearrangements in human T-cell acute leukemia/lymphoma (T-ALL), a malignancy often associated with activated Notch and Akt signaling. To address how epigenetic reprogramming via an activated homeobox gene might contribute to T-lymphomagenesis, we investigated a transgenic mouse model with thymocyte-specific overexpression of the Dlx5 homeobox gene. We demonstrate for the first time that Dlx5 induces T-cell lymphomas with high penetrance. Integrated ChIP-seq and mRNA microarray analyses identified Notch1/3 and Irs2 as direct transcriptional targets of Dlx5, a gene signature unique to lymphomas from Lck-Dlx5 mice as compared to T-cell lymphomas from Lck-MyrAkt2 mice, which were previously reported by our group. Moreover, promoter/enhancer studies confirmed that Dlx5 directly transactivates Notch expression. Notch1/3 expression and Irs2-induced Akt signaling were upregulated throughout early stages of T-cell development, which promoted cell survival during β-selection of T lymphocytes. Dlx5 was required for tumor maintenance via its activation of Notch and Akt, as tumor cells were highly sensitive to Notch and Akt inhibitors. Together, these findings provide unbiased genetic and mechanistic evidence that Dlx5 acts as an oncogene when aberrantly expressed in T cells, and that it is a novel discovery that Notch is a direct target of Dlx5. These experimental findings provide mechanistic insights about how reactivation of the Dlx5 gene can drive T-ALL by aberrant epigenetic reprogramming of the T-cell genome.

Becker MA, Ibrahim YH, Oh AS, et al.
Insulin Receptor Substrate Adaptor Proteins Mediate Prognostic Gene Expression Profiles in Breast Cancer.
PLoS One. 2016; 11(3):e0150564 [PubMed] Free Access to Full Article Related Publications
Therapies targeting the type I insulin-like growth factor receptor (IGF-1R) have not been developed with predictive biomarkers to identify tumors with receptor activation. We have previously shown that the insulin receptor substrate (IRS) adaptor proteins are necessary for linking IGF1R to downstream signaling pathways and the malignant phenotype in breast cancer cells. The purpose of this study was to identify gene expression profiles downstream of IGF1R and its two adaptor proteins. IRS-null breast cancer cells (T47D-YA) were engineered to express IRS-1 or IRS-2 alone and their ability to mediate IGF ligand-induced proliferation, motility, and gene expression determined. Global gene expression signatures reflecting IRS adaptor specific and primary vs. secondary ligand response were derived (Early IRS-1, Late IRS-1, Early IRS-2 and Late IRS-2) and functional pathway analysis examined. IRS isoforms mediated distinct gene expression profiles, functional pathways, and breast cancer subtype association. For example, IRS-1/2-induced TGFb2 expression and blockade of TGFb2 abrogated IGF-induced cell migration. In addition, the prognostic value of IRS proteins was significant in the luminal B breast tumor subtype. Univariate and multivariate analyses confirmed that IRS adaptor signatures correlated with poor outcome as measured by recurrence-free and overall survival. Thus, IRS adaptor protein expression is required for IGF ligand responses in breast cancer cells. IRS-specific gene signatures represent accurate surrogates of IGF activity and could predict response to anti-IGF therapy in breast cancer.

Liu TT, You HL, Weng SW, et al.
Recurrent Amplification at 13q34 Targets at CUL4A, IRS2, and TFDP1 As an Independent Adverse Prognosticator in Intrahepatic Cholangiocarcinoma.
PLoS One. 2015; 10(12):e0145388 [PubMed] Free Access to Full Article Related Publications
Amplification of genes at 13q34 has been reported to be associated with tumor proliferation and progression in diverse types of cancers. However, its role in intrahepatic cholangiocarcinoma (iCCA) has yet to be explored. We examined two iCCA cell lines and 86 cases of intrahepatic cholangiocarcinoma to analyze copy number of three target genes, including cullin 4A (CUL4A), insulin receptor substrate 2 (IRS2), and transcription factor Dp-1 (TFDP1) at 13q34 by quantitative real-time polymerase chain reaction. The cell lines and all tumor samples were used to test the relationship between copy number (CN) alterations and protein expression by western blotting and immunohistochemical assays, respectively. IRS2 was introduced, and each target gene was silenced in cell lines. The mobility potential of cells was compared in the basal condition and after manipulation using cell migration and invasion assays. CN alterations correlated with protein expression levels. The SNU1079 cell line containing deletions of the target genes demonstrated decreased protein expression levels and significantly lower numbers of migratory and invasive cells, as opposed to the RBE cell line, which does not contain CN alterations. Overexpression of IRS2 by introducing IRS2 in SUN1079 cells increased the mobility potential. In contrast, silencing each target gene showed a trend or statistical significance toward inhibition of migratory and invasive capacities in RBE cells. In tumor samples, the amplification of each of these genes was associated with poor disease-free survival. Twelve cases (13.9%) demonstrated copy numbers > 4 for all three genes tested (CUL4A, IRS2, and TFDP1), and showed a significant difference in disease-free survival by both univariate and multivariate survival analyses (hazard ratio, 2.69; 95% confidence interval, 1.23 to 5.88; P = 0.013). Our data demonstrate that amplification of genes at 13q34 plays an oncogenic role in iCCA featuring adverse disease-free survival, which may provide new directions for targeted therapy.

Liu H, Ren G, Zhu L, et al.
The upregulation of miRNA-146a inhibited biological behaviors of ESCC through inhibition of IRS2.
Tumour Biol. 2016; 37(4):4641-7 [PubMed] Related Publications
In recent years, microRNAs, also called as miRNAs, play an important role in carcinogenesis, and the dysregulation of miRNAs is closely associated with cancer progression. Till now, little has been known about the role of miRNA-146a in the esophageal squamous cell carcinomas (ESCC). In the present study, we used in vitro assays to investigate the mechanisms of miRNA-146a in ESCC cell lines and 60 ESCC tissues. Here, we found that miRNA-146a expression is downregulated in both ESCC cell lines and tissues and obviously associated with pathological indicators, such as metastasis and stage of ESCC. In addition, the overexpression of miRNA-146a suppressed EC109 and TE8 cell proliferation and invasion. Meanwhile, miRNA-146a overexpression extremely inhibited the protein expression of insulin receptor substrate 2 (IRS2). Notably, the enforced expression of IRS2 in EC109 cells with miRNA-146a overexpression attenuated the inhibitory effects of miRNA-146a. In conclusion, our findings suggest that miRNA-146a may function as a useful clinical tool in the treatment and diagnosis of ESCC, and its overexpression suppressed cell growth through inhibition of IRS2. Thus, miRNA-146a pathway may be recommended as potential makers for drug design.

Bertotti A, Papp E, Jones S, et al.
The genomic landscape of response to EGFR blockade in colorectal cancer.
Nature. 2015; 526(7572):263-7 [PubMed] Free Access to Full Article Related Publications
Colorectal cancer is the third most common cancer worldwide, with 1.2 million patients diagnosed annually. In late-stage colorectal cancer, the most commonly used targeted therapies are the monoclonal antibodies cetuximab and panitumumab, which prevent epidermal growth factor receptor (EGFR) activation. Recent studies have identified alterations in KRAS and other genes as likely mechanisms of primary and secondary resistance to anti-EGFR antibody therapy. Despite these efforts, additional mechanisms of resistance to EGFR blockade are thought to be present in colorectal cancer and little is known about determinants of sensitivity to this therapy. To examine the effect of somatic genetic changes in colorectal cancer on response to anti-EGFR antibody therapy, here we perform complete exome sequence and copy number analyses of 129 patient-derived tumour grafts and targeted genomic analyses of 55 patient tumours, all of which were KRAS wild-type. We analysed the response of tumours to anti-EGFR antibody blockade in tumour graft models and in clinical settings and functionally linked therapeutic responses to mutational data. In addition to previously identified genes, we detected mutations in ERBB2, EGFR, FGFR1, PDGFRA, and MAP2K1 as potential mechanisms of primary resistance to this therapy. Novel alterations in the ectodomain of EGFR were identified in patients with acquired resistance to EGFR blockade. Amplifications and sequence changes in the tyrosine kinase receptor adaptor gene IRS2 were identified in tumours with increased sensitivity to anti-EGFR therapy. Therapeutic resistance to EGFR blockade could be overcome in tumour graft models through combinatorial therapies targeting actionable genes. These analyses provide a systematic approach to evaluating response to targeted therapies in human cancer, highlight new mechanisms of responsiveness to anti-EGFR therapies, and delineate new avenues for intervention in managing colorectal cancer.

Anjali G, Kaur S, Lakra R, et al.
FSH stimulates IRS-2 expression in human granulosa cells through cAMP/SP1, an inoperative FSH action in PCOS patients.
Cell Signal. 2015; 27(12):2452-66 [PubMed] Related Publications
Follicle stimulating hormone (FSH) plays a central role in growth and differentiation of ovarian follicles. A plethora of information exists on molecular aspects of FSH responses but little is known about the mechanisms involved in its cross-talk with insulin/IGF-1 pathways implicated in the coordination of energy homeostasis in preovulatory granulosa cells (GCs). In this study, we hypothesized that FSH may regulate IRS-2 expression and thereby maintain the energy balance in GCs. We demonstrate here that FSH specifically increases IRS-2 expression in human and rat GCs. FSH-stimulated IRS-2 expression was inhibited by actinomycin D or cycloheximide. Furthermore, FSH decreases IRS-2 mRNA degradation indicating post-transcriptional stabilization. Herein, we demonstrate a role of cAMP pathway in the activation of IRS-2 expression by FSH. Scan and activity analysis of IRS-2 promoter demonstrated that FSH regulates IRS-2 expression through SP1 binding sites. FSH stimulates SP1 translocation into nucleus and its binding to IRS-2 promoter. These results are corroborated by the fact that siRNA mediated knockdown of IRS-2 decreased the FSH-stimulated PI3K activity, p-Akt levels, GLUT4 translocation and glucose uptake. However, FSH was not able to increase IRS-2 expression in GCs from PCOS women undergoing IVF. Interestingly, IRS-2 mRNA expression was downregulated in GCs from the PCOS rat model. Taken together, our findings establish that FSH induces IRS-2 expression and thereby activates PI3K, Akt and glucose uptake. Crucially, our data confirms a molecular defect in FSH action in PCOS GCs which may cause deceleration of metabolism and follicular growth leading to infertility. These results lend support for a therapeutic potential of IRS-2 in the management of PCOS.

Park DH, Jeon HS, Lee SY, et al.
MicroRNA-146a inhibits epithelial mesenchymal transition in non-small cell lung cancer by targeting insulin receptor substrate 2.
Int J Oncol. 2015; 47(4):1545-53 [PubMed] Related Publications
During cancer progression, some tumor cells show changes in their plasticity by morphological and phenotypical conversions, as an expression of mesenchymal markers and loss of epithelial markers, collectively referred to as epithelial-mesenchymal transition (EMT). EMT has been increasingly recognized as a critical phenomenon in lung cancer progression. The goal of this study was to identify microRNAs involved in lung cancer progression. A microarray and qRT-PCR were performed to investigate the miRNA expression profiles in mesenchymal-like lung cancer cells. The role of miR‑146a in lung cancer progression was measured by invasion and migration assays in vitro. Bioinformatics and luciferase report assays were used to identify the target of miR‑146a. The expression of miR‑146a was reduced in mesenchymal-like lung cancer cell lines. The overexpression of miR‑146a induced a marked reduction of the mesenchymal marker and increase the epithelial marker in lung cancer cell lines. Moreover, the overexpression of miR‑146a suppressed lung cancer cell migration and invasion. Co-treatment with miR‑146a and gefitinib treatment showed a significant reduction of invasion in the resistant lung cancer cells induced by EMT. The expression of miR‑146a was downregulated in advanced lung cancer tissues. Insulin receptor substrate 2 (IRS2), an adaptor protein that modulates normal growth, metabolism, survival, and differentiation, was identified as a target of miR‑146a. miR‑146a regulated the expression of IRS2 at the mRNA and protein levels. These data demonstrate for the first time that miR‑146a suppresses lung cancer progression by repressing IRS2 expression. This provides new insight into the post-transcriptional regulation of lung cancer progression by miRNAs, a potential approach for the treatment of lung cancer.

Xin C, Jing D, Jie T, et al.
The expression difference of insulin-like growth factor 1 receptor in breast cancers with or without diabetes.
J Cancer Res Ther. 2015 Apr-Jun; 11(2):295-9 [PubMed] Related Publications
CONTEXT: The insulin-like growth factor (IGF) and insulin receptors' (IR) axes play important roles in both breast cancer and diabetes mellitus.
AIM: We tend to explore the expression characteristics of proteins in IGF/IR axis in breast cancer with type 2 diabetes mellitus (T2DM).
SETTINGS AND DESIGN: We conducted a case-control investigation of T2DM and non-diabetes (n = 40, 1:1) in breast cancer patients.
MATERIALS AND METHODS: Some important molecules of IGF/IR axis were detected in breast cancer tissues by immunohistochemical staining. The multivariable analyses of the relationship of clinicopathological characters with the significant molecules were also detected.
STATISTICAL ANALYSIS USED: The results were statistically evaluated by Statistical Package for the Social Sciences (SPSS version 17.0) software. Chi-square test and logistic regression are used.
RESULTS: Higher expression of IGF 1 receptor (IGF1R) was found in breast cancers of patients with T2DM, compared those without diabetes (P = 0.044). Negative expression of human epidermal growth factor receptor 2 (Her2) was found to be associated with higher expression of IGF1R in the breast cancers of patients with T2DM. There were no differences found in the expression of proteins of IGF-1, IGF-2, IGF-binding protein 3 (IGFBP3), IR, insulin receptor substrate (IRS)-1, IRS-2 and mammalian target of rapamycin (mTOR) between T2DM group and non-diabetes group.
CONCLUSION: Our study found that breast cancer with T2DM had a higher expression of IGF1R, and the higher IGF1R was associated with negative Her2 expression.

Wheler JJ, Atkins JT, Janku F, et al.
Multiple gene aberrations and breast cancer: lessons from super-responders.
BMC Cancer. 2015; 15:442 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: The presence of multiple molecular aberrations in patients with breast cancer may correlate with worse outcomes.
CASE PRESENTATIONS: We performed in-depth molecular analysis of patients with estrogen receptor-positive, HER2-negative, hormone therapy-refractory breast cancer, who achieved partial or complete responses when treated with anastrozole and everolimus. Tumors were analyzed using a targeted next generation sequencing (NGS) assay in a Clinical Laboratory Improvement Amendments laboratory. Genomic libraries were captured for 3,230 exons in 182 cancer-related genes plus 37 introns from 14 genes often rearranged in cancer and sequenced to high coverage. Patients received anastrozole (1 g PO daily) and everolimus (5 or 10 mg PO daily). Thirty-two patients with breast cancer were treated on study and 5 (16 %) achieved a partial or complete response. Primary breast tissue was available for NGS testing in three of the responders (partial response with progression free survival of 11 and 14 months, respectively; complete response with progression free survival of 9+ months). The following molecular aberrations were observed: PTEN loss by immunohistochemistry, CCDN1 and FGFR1 amplifications, and PRKDC re-arrangement (NGS) (patient #1); PIK3CA and PIK3R1 mutations, and CCDN1, FGFR1, MYC amplifications (patient #2); TP53 mutation, CCNE1, IRS2 and MCL1 amplifications (patient #3). Some (but not all) of these aberrations converge on the PI3K/AKT/mTOR pathway, perhaps accounting for response.
CONCLUSIONS: Patients with estrogen receptor-positive breast cancer can achieve significant responses on a combination of anastrozole and everolimus, even in the presence of multiple molecular aberrations. Further study of next generation sequencing-profiled tumors for convergence and resistance pathways is warranted.

Ma Y, Zhang H, He X, et al.
miR-106a* inhibits the proliferation of renal carcinoma cells by targeting IRS-2.
Tumour Biol. 2015; 36(11):8389-98 [PubMed] Related Publications
MicroRNAs play critical roles in the development and progression of human cancers. Although it has been reported that miR-106a* is downregulated in follicular lymphoma, its role in renal cell carcinoma (RCC) remains unknown. This study investigated the expression and role of miR-106a* in human RCC. Our results showed that the miR-106a* expression decreased dramatically in clinical RCC tissues and cell lines. In vitro, overexpression of miR-106a* suppressed RCC cell proliferation and S/G2 transition, whereas inhibition of miR-106a* promoted cell proliferation and S/G2 transition. It was also found that miR-106a* expression was inversely correlated with the expression of insulin receptor substrate 2 (IRS-2). IRS-2 was determined to be a direct target of miR-106a* by a luciferase reporter assay. Importantly, silencing IRS-2 resulted in the same biologic effects as those of miR-106a* overexpression in RCC cells, including inhibition of RCC cell proliferation and triggering of S/G2 cell cycle arrest with inhibition of the PI3K/Akt signaling pathway. These results indicate that miR-106a* affects RCC progression by targeting IRS-2 with suppression of the PI3K/Akt signaling pathway in RCC cells. The findings suggest miR-106a* as a novel strategy for RCC treatment.

Zekri AR, Hassan ZK, Bahnassy AA, et al.
Differentially expressed genes in metastatic advanced Egyptian bladder cancer.
Asian Pac J Cancer Prev. 2015; 16(8):3543-9 [PubMed] Related Publications
BACKGROUND: Bladder cancer is one of the most common cancers worldwide. Gene expression profiling using microarray technologies improves the understanding of cancer biology. The aim of this study was to determine the gene expression profile in Egyptian bladder cancer patients.
MATERIALS AND METHODS: Samples from 29 human bladder cancers and adjacent non-neoplastic tissues were analyzed by cDNA microarray, with hierarchical clustering and multidimensional analysis.
RESULTS: Five hundred and sixteen genes were differentially expressed of which SOS1, HDAC2, PLXNC1, GTSE1, ULK2, IRS2, ABCA12, TOP3A, HES1, and SRP68 genes were involved in 33 different pathways. The most frequently detected genes were: SOS1 in 20 different pathways; HDAC2 in 5 different pathways; IRS2 in 3 different pathways. There were 388 down-regulated genes. PLCB2 was involved in 11 different pathways, MDM2 in 9 pathways, FZD4 in 5 pathways, p15 and FGF12 in 4 pathways, POLE2 in 3 pathways, and MCM4 and POLR2E in 2 pathways. Thirty genes showed significant differences between transitional cell cancer (TCC) and squamous cell cancer (SCC) samples. Unsupervised cluster analysis of DNA microarray data revealed a clear distinction between low and high grade tumors. In addition 26 genes showed significant differences between low and high tumor stages, including fragile histidine triad, Ras and sialyltransferase 8 (alpha) and 16 showed significant differences between low and high tumor grades, like methionine adenosyl transferase II, beta.
CONCLUSIONS: The present study identified some genes, that can be used as molecular biomarkers or target genes in Egyptian bladder cancer patients.

Cui A, Hua H, Shao T, et al.
Aflatoxin B1 induces Src phosphorylation and stimulates lung cancer cell migration.
Tumour Biol. 2015; 36(8):6507-13 [PubMed] Related Publications
AflatoxinB1 (AFB1) is well known as a potent carcinogen. Epidemiological studies have shown an association between AFB1 exposure and lung cancer in humans. AFB1 can induce the mutations of genes such as tumor suppressor p53 through its metabolite AFB1-8,9-exo-epoxide, which acts as a mutagen to react with DNA. In addition, recent study demonstrates AFB1 positively regulates type I insulin-like growth factor receptor (IGF-IR) signaling in hepatoma cells. The current study aims to determine the effects of AFB1 on Src kinase and insulin receptor substrate (IRS) in lung cancer cells and the effects of AFB1 on lung cancer cell migration. To this end, the effects of AFB1 on IRS expression, Src, Akt, and ERK phosphorylation were measured by Western blot analysis. The migration of lung cancer cells was detected by wound-healing assay. AFB1 downregulates IRS1 but paradoxically upregulates IRS2 through positive regulation of the stability of IRS2 and the proteasomal degradation of IRS1 in lung cancer cell lines A549 and SPCA-1. In addition, AFB1 induces Src, Akt, and ERK1/2 phosphorylation. Treatment of lung cancer cells with Src inhibitor saracatinib abrogates AFB1-induced IRS2 accumulation. Moreover, AFB1 stimulates lung cancer cell migration, which can be inhibited by saracatinib. We conclude that AFB1 may upregulate IRS2 and stimulate lung cancer cell migration through Src.

Nunes M, Vrignaud P, Vacher S, et al.
Evaluating patient-derived colorectal cancer xenografts as preclinical models by comparison with patient clinical data.
Cancer Res. 2015; 75(8):1560-6 [PubMed] Related Publications
Development of targeted therapeutics required translationally relevant preclinical models with well-characterized cancer genome alterations. Here, by studying 52 colorectal patient-derived tumor xenografts (PDX), we examined key molecular alterations of the IGF2-PI3K and ERBB-RAS pathways and response to cetuximab. PDX molecular data were compared with that published for patient colorectal tumors in The Cancer Genome Atlas. We demonstrated a significant pattern of mutual exclusivity of genomic abnormalities in the IGF2-PI3K and ERBB-RAS pathways. The genomic anomaly frequencies observed in microsatellite stable PDX reproduce those detected in nonhypermutated patient tumors. We found frequent IGF2 upregulation (16%), which was mutually exclusive with IRS2, PIK3CA, PTEN, and INPP4B alterations, supporting IGF2 as a potential drug target. In addition to maintaining the genomic and histologic diversity, correct preclinical models need to reproduce drug response observed in patients. Responses of PDXs to cetuximab recapitulate also clinical data in patients, with partial or complete response in 15% (8 of 52) of PDXs and response strictly restricted to KRAS wild-type models. The response rate reaches 53% (8 of 15) when KRAS, BRAF, and NRAS mutations are concomitantly excluded, proving a functional cross-validation of predictive biomarkers obtained retrospectively in patients. Collectively, these results show that, because of their clinical relevance, colorectal PDXs are appropriate tools to identify both new targets, like IGF2, and predictive biomarkers of response/resistance to targeted therapies.

Zhang Q, Tang Q, Qin D, et al.
Role of microRNA 30a targeting insulin receptor substrate 2 in colorectal tumorigenesis.
Mol Cell Biol. 2015; 35(6):988-1000 [PubMed] Free Access to Full Article Related Publications
MicroRNAs (miRNAs) are dysregulated in many types of malignant diseases, including colorectal cancer. miRNA 30a (miR-30a) is a member of the miR-30 family and has been implicated in many types of cancers. In this study, we determined the expression of miR-30a in human colon cancer tissues and cell lines. miR-30a was found to be significantly downregulated in both the tissues and cell lines. Furthermore, overexpression of miR-30a inhibited, while silencing of miR-30a promoted, cell proliferation, migration, and invasion in vitro. Consistently, stable overexpression of miR-30a suppressed the growth of colon cancer cell xenografts in vivo. Moreover, bioinformatic algorithms and luciferase reporter assays revealed that insulin receptor substrate 2 (IRS2) is a direct target of miR-30a. Further functional studies suggested that repression of IRS2 by miR-30a partially mediated the tumor suppressor effect of miR-30a. In addition, miR-30a inhibited constitutive phosphorylation of Akt by targeting IRS2. Additionally, clinicopathological analysis indicated that miR-30a has an inverse correlation with the staging in patients with colon cancer. Taken together, our study provides the first evidence that miR-30a suppressed colon cancer cell growth through inhibition of IRS2. Thus, miR-30a might serve as a promising therapeutic strategy for colon cancer treatment.

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.

Huang F, Chang H, Greer A, et al.
IRS2 copy number gain, KRAS and BRAF mutation status as predictive biomarkers for response to the IGF-1R/IR inhibitor BMS-754807 in colorectal cancer cell lines.
Mol Cancer Ther. 2015; 14(2):620-30 [PubMed] Related Publications
Insulin-like growth factor receptor 1 (IGF-1R)-targeting therapies are currently at an important crossroad given the low clinical response rates seen in unselected patients. Predictive biomarkers for patient selection are critical for improving clinical benefit. Coupling in vitro sensitivity testing of BMS-754807, a dual IGF-1R/IR inhibitor, with genomic interrogations in 60 human colorectal cancer cell lines, we identified biomarkers correlated with response to BMS-754807. The results showed that cell lines with BRAF(V600E) or KRAS(G13D) mutation were resistant, whereas cell lines with wild-type of both KRAS and BRAF were particularly sensitive to BMS-754807 if they have either higher RNA expression levels of IR-A or lower levels of IGFBP6. In addition, the cell lines with KRAS mutations, those with either insulin receptor substrate 2 (IRS2) copy number gain (CNG) or higher IGF-1R expression levels, were more sensitive to the drug. Furthermore, cell lines with IRS2 CNG had higher levels of ligand-stimulated activation of IGF-1R and AKT, suggesting that these cell lines with IGF-IR signaling pathways more actively coupled to AKT signaling are more responsive to IGF-1R/IR inhibition. IRS2 siRNA knockdown reduced IRS2 protein expression levels and decreased sensitivity to BMS-754807, providing evidence for the functional involvement of IRS2 in mediating the drug response. The prevalence of IRS2 CNG in colorectal cancer tumors as measured by qPCR-CNV is approximately 35%. In summary, we identified IRS2 CNG, IGF-1R, IR-A, and IGFBP6 RNA expression levels, and KRAS and BRAF mutational status as candidate predictive biomarkers for response to BMS-754807. This work proposed clinical development opportunities for BMS-754807 in colorectal cancer with patient selection to improve clinical benefit.

Lin MW, Huang MF, Wu MH
Association of Gly972Arg variant of insulin receptor subtrate-1 and Gly1057Asp variant of insulin receptor subtrate-2 with polycystic ovary syndrome in the Chinese population.
J Ovarian Res. 2014; 7:92 [PubMed] Free Access to Full Article Related Publications
OBJECTIVE: Polycystic ovary syndrome (PCOS) is a common endocrinologic disease in women. In the present study, we examined the relationship of the IRS-1 Gly972Arg and IRS-2 Gly1057Asp polymorphisms to PCOS and phenotypic features of PCOS in a Chinese population from Taiwan.
MATERIALS AND METHODS: A total of three hundred and forty genetically unrelated women with age from 18 to 45 years, including two hundred and forty-eight PCOS patients and ninety-two control subjects, were recruited. The hormone and biochemical measurements were evaluated for each woman. Genotyping of the IRS-1 gene Gly972Arg variant and IRS-2 gene Gly1057Asp variant were performed by using direct sequencing.
RESULTS: We found significant difference in the genotypic distribution of IRS-2 gene Gly1057Asp between the PCOS group and the control group (p = 0.004). The carriers of homozygous IRS-2 Asp had an increased risk of PCOS compared with the carriers of Gly/Gly (OR 4.08, 95% C.I. 1.60-10.41, p = 0.003). No significant difference in genotype frequencies of IRS-1 Gly972Arg was observed between two groups. We further investigated the effect of interaction of IRS-1 Gly972Arg and IRS-2 Gly1057Asp on the risk of PCOS and found that women carried IRS-1 Gly/Arg or IRS-2 Asp/Asp or carried both IRS-1 Gly/Arg and IRS-2 Asp/Asp had a much higher risk of PCOS compared with their counterpart, respectively (OR 2.49, 95% C.I. 1.16-5.37, p = 0.019; OR 11.87, 95% C.I. 1.21-116.84, p = 0.034). We further found, the non-obese PCOS patients carried significantly higher frequency of IRS-2 Asp/Asp as compared with the control group (p = 0.004). A significant effect of interaction of carrying both IRS-1 Gly/Arg and IRS-2 Asp/Asp was also observed in the non-obese PCOS patients (p = 0.003), but not in the obese PCOS patients.
CONCLUSIONS: In this study, we found significant association of the variant of IRS-2 gene as well as the interaction of IRS-1 and IRS-2 genes with PCOS, especially in non-obese women. Women with IRS-2 homozygous Asp variant may be considered as a risk factor for PCOS that needs early detection to prevent further complication in the Chinese population from Taiwan.

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