Research IndicatorsGraph generated 25 June 2015 using data from PubMed using criteria.
Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic. Tag cloud generated 25 June, 2015 using data from PubMed, MeSH and CancerIndex
Specific Cancers (5)
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).
OMIM, Johns Hopkin University
Referenced article focusing on the relationship between phenotype and genotype.
International Cancer Genome Consortium.
Summary of gene and mutations by cancer type from ICGC
Cancer Genome Anatomy Project, NCI
COSMIC, Sanger Institute
Somatic mutation information and related details
Search the Epigenomics database and view relevant gene tracks of samples.
Latest Publications: LRIG1 (cancer-related)
BACKGROUND: Optimal treatment decisions for cancer patients require reliable prognostic and predictive information. However, this information is inadequate in many cases. Several recent studies suggest that the leucine-rich repeats and immunoglobulin-like domains (LRIG) genes, transcripts, and proteins have prognostic implications in various cancer types.
MATERIAL AND METHODS: Relevant literature was identified on PubMed using the key words lrig1, lrig2, and lrig3. LRIG mRNA expression in cancer versus normal tissues was investigated using the Oncomine database.
RESULTS: The three human LRIG genes, LRIG1, LRIG2, and LRIG3, encode single-pass transmembrane proteins. LRIG1 is a negative regulator of growth factor signaling that has been shown to function as a tumor suppressor in vitro and in vivo in mice. The functions of LRIG2 and LRIG3 are less well defined. LRIG gene and protein expression are commonly dysregulated in human cancer. In early stage breast cancer, LRIG1 copy number was recently shown to predict early and late relapse in addition to overall survival; in nasopharyngeal carcinoma, loss of LRIG1 is also associated with poor survival. LRIG gene and protein expression have prognostic value in breast cancer, uterine cervical cancer, head-and-neck cancer, glioma, non-small cell lung cancer, prostate cancer, and cutaneous squamous cell carcinoma. In general, expression of LRIG1 and LRIG3 is associated with good survival, whereas expression of LRIG2 is associated with poor survival. Additionally, LRIG1 regulates cellular sensitivity to anti-cancer drugs, which indicates a possible role as a predictive marker.
CONCLUSIONS: LRIG gene statuses and mRNA and protein expression are clinically relevant prognostic indicators in several types of human cancer. We propose that LRIG analyses could become important when making informed and individualized clinical decisions regarding the management of cancer patients.
PURPOSE: Leucine-rich repeats and immunoglobulin-like domains 1 (LRIG1) are an inhibitor of receptor tyrosine kinases (RTKs) that was discovered in recent years, and many studies showed that LRIG1 is a tumor suppressor gene and may be related to tumor drug resistance. In this study, we explored whether LRIG1 protein expression can improve the chemosensitivity of glioma cells and what was its mechanism.
MATERIALS AND METHODS: We collected 93 cases of glioma tissues and detected the expression of LRIG1 and BCL-2. We constructed a multidrug resistance cell line U251/multidrug resistance (MDR) and examined the change of LRIG1 and BCL-2 at mRNA and protein expression levels. LRIG1 expression was upregulated in U251/MDR cells and we detected the change of multidrug resistance. Meanwhile, we changed the expression of LRIG1 and BCL-2 and explored the relationship between LRIG1 and BCL-2. Finally, we also explored the relationship between LRIG1 and RTKs.
RESULTS: LRIG1 was negatively correlated with BCL-2 expression in glioma tissue and U251/MDR cells, and upregulation of LRIG1 can enhance chemosensitivity and inhibit BCL-2 expression. Furthermore, LRIG1 was negatively correlated with RTKs in U251/MDR cells.
CONCLUSION: These results demonstrated that LRIG1 can improve chemosensitivity by modulating BCL-2 expression and RTK signaling in glioma cells.
Lindström AK, Hellberg DImmunohistochemical LRIG3 expression in cervical intraepithelial neoplasia and invasive squamous cell cervical cancer: association with expression of tumor markers, hormones, high-risk HPV-infection, smoking and patient outcome.
Eur J Histochem. 2014; 58(2):2227 [PubMed
] Free Access to Full Article Related Publications
The novel biomarker LRIG3 is a member of the LRIG family (LRIG1-3). While LRIG1 has been associated with favorable prognosis and LRIG2 with poor prognosis in invasive cervical cancer, little is known about the role of LRIG3. The aim of this study was to investigate the expression of LRIG3 in invasive cancer and cervical intraepithelial neoplasia (CIN) for possible correlation with other tumor markers, to hormones and smoking, as a diagnostic adjunct in CIN, and prognostic value in invasive cancer. Cervical biopsies from 129 patients with invasive squamous cell carcinoma and 170 biopsies showing low grade and high grade CIN, or normal epithelium were stained for LRIG3 and 17 additional tumor markers. Among other variables the following were included: smoking habits, hormonal contraceptive use, serum progesterone, serum estradiol, high-risk HPV-infection, menopausal status and ten-year survival. In CIN, high expression of the tumor suppressors retinoblastoma protein, p53, and p16, and E-cadherin (cell-cell interaction), or low expression of CK10, correlated to LRIG3 expression. In addition, progestogenic contraceptive use correlated to high expression of LRIG3. In invasive cancer there was a correlation between expression of the major tumor promoter c-myc and high LRIG3 expression. High LRIG3 expression correlated significantly to presence of high-risk HPV infection in patients with normal epithelium and CIN. There was no correlation between LRIG3 expression and 10-year survival in patients with invasive cell cervical cancer. LRIG3 expression is associated with a number of molecular events in CIN. Expression also correlates to hormonal contraceptive use. The results on expression of other tumor markers suggest that LRIG3 is influenced by or influences a pattern of tumor markers in cancer and precancerous cells. Further studies are needed to elucidate if LRIG3 expression might be clinically useful.
Chen YZ, Fan ZH, Zhao YX, et al.Single-nucleotide polymorphisms of LIG1 associated with risk of lung cancer.
Tumour Biol. 2014; 35(9):9229-32 [PubMed
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To investigate the association of LIG1 with the risk of lung cancer, all subjects of unrelated ethnic Han Chinese in Liaoning Province were involved in a hospital-based case-control study. The case group consisted of 370 histologically diagnosed lung cancer patients; 314 controls were selected from cancer-free patients during Dec. 2009 to Dec. 2011. LIG1 rs1050298SNP were analyzed by TaqMan real-time PCR method. All statistical analyses were performed with Statistical Product and Service Solution sv13.0 (SPSS). The genotype distribution frequency of LIG1 rs1050298 SNP displayed significant difference between the case and the control group. Individuals carrying the LIG1 rs1050298 T genotype had higher risks of lung cancer, especially those with squamous cell carcinoma.
Thompson PA, Ljuslinder I, Tsavachidis S, et al.Loss of LRIG1 locus increases risk of early and late relapse of stage I/II breast cancer.
Cancer Res. 2014; 74(11):2928-35 [PubMed
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Gains and losses at chromosome 3p12-21 are common in breast tumors and associated with patient outcomes. We hypothesized that the LRIG1 gene at 3p14.1, whose product functions in ErbB-family member degradation, is a critical tumor modifier at this locus. We analyzed 971 stage I/II breast tumors using Affymetrix Oncoscan molecular inversion probe arrays that include 12 probes located within LRIG1. Copy number results were validated against gene expression data available in the public database. By partitioning the LRIG1 probes nearest exon 12/13, we confirm a breakpoint in the gene and show that gains and losses in the subregions differ by tumor and patient characteristics including race/ethnicity. In analyses adjusted for known prognostic factors, loss of LRIG1 was independently associated with risk of any relapse (HR, 1.90; 95% CI, 1.32-2.73), relapse≥5 years (HR, 2.39; 95% CI, 1.31-4.36), and death (HR, 1.55; 95% CI, 1.11-2.16). Analyses of copy number across chromosome 3, as well as expression data from pooled, publicly available datasets, corroborated the hypothesis of an elevated and persistent risk among cases with loss of or low LRIG1. We concluded that loss/low expression of LRIG1 is an independent risk factor for breast cancer metastasis and death in stage I/II patients. Increased hazard in patients with loss/low LRIG1 persists years after diagnosis, suggesting that LRIG1 is acting as a critical suppressor of tumor metastasis and is an early clinical indicator of risk for late recurrences in otherwise low-risk patients.
The leucine rich repeats and immunoglobulin-like protein 1 (LRIG1) is a newly discovered negative regulator of epidermal growth factor receptor (EGFR) and a proposed tumor suppressor. It is not universally downregulated in human cancers, and its role in neoplastic transformation and tumorigenesis is not well-documented. In this study, we show the expression of LRIG1 as a novel potential marker for neoplastic transformation in ocular-surface squamous neoplasia (OSSN). The following two groups were included in this study: 1) benign group (3 cases; 1 with papilloma and 2 with dysplasia) and 2) malignant group (3 cases with squamous cell carcinoma (SCC)). In both groups, immunofluorescence analysis was firstly performed for keratins 4, 12, 13, and 15 to characterize the state of differentiation, and for Ki67 to evaluate the proliferation activity. Subsequently, LRIG1 and EGFR expression was analyzed. Either keratin 4 and/or 13, both non-keratinized epithelial cell markers, were generally expressed in both groups, except for 1 severe SCC case. Keratin 15, an undifferentiated basal cell marker, was more strongly expressed in the malignant cases than in the benign cases. The Ki67 index was significantly higher (P<0.002) in the malignant group (33.2%) than in the benign group (10.9%). LRIG1 expression was limited to basal epithelial cells in normal corneal epithelial tissue. Interestingly, LRIG1 was expressed throughout the epithelium in all the benign cases. In contrast, its expression was limited or totally disappeared in the malignant cases. Inversely, EGFR staining was faintly expressed in the benign cases, yet strongly expressed in the malignant cases. Malignant tissue with proliferative potential presented EGFR overexpression and inverse downregulation of LRIG1, consistent with LRIG1 being a suppressor of neoplastic transformation by counteracting the tumor growth property of EGFR. Our findings indicate that downregulation of LRIG1 is possibly a novel potential marker of transformation and tumorigenesis in OSSN cases.
BACKGROUND: Recently, leucine-rich repeats and immunoglobulin-like domains 1 (LRIG1), a negative regulator of EGFR, was discovered is a novel agent for suppressing bladder cancer. The aim of this study was to investigate the impact of LRIG1 on the biological features of aggressive bladder cancer cells and the possible mechanisms of enhanced apoptosis induced by upregulation of LRIG1.
METHODS: In this study, we examined the mRNA and protein expression of LRIG1 and EGFR in bladder cancers and normal bladder. Meanwhile, we overexpressed LRIG1 with adenovirus vector in T24/5637 bladder cancer cell lines, and we used real time-PCR, western blot, and co-immunoprecipitation analysis in order to examine the effects of LRIG1 gene on EGFR. Furthermore, we evaluate the impact of LRIG1 gene on the function of human bladder cancer cells and EGFR signaling.
RESULTS: The expression of LRIG1 was decreased, while the expression of EGFR was increased in the majority of bladder cancer, and the ratio of EGFR/LRIG1 was increased in tumors versus normal tissue. We found that upregulation of LRIG1 induced cell apoptosis and cell growth inhibition, and further reversed invasion in bladder cancer cell lines in vitro by inhibiting phosphorylation of downstream MAPK and AKT signaling pathway.
CONCLUSION: Taken together, our findings provide us with an insight into LRIG1 function, and we conclude that LRIG1 evolved in bladder cancer as a rare feedback negative attenuator of EGFR, thus could offer a novel therapeutic target to treat patients with bladder cancer.
BACKGROUND: The leucine-rich repeats and immunoglobulin-like domains (LRIG) proteins constitute an integral membrane protein family that has three members: LRIG1, LRIG2, and LRIG3. LRIG1 negatively regulates growth factor signaling, but little is known regarding the functions of LRIG2 and LRIG3. In oligodendroglial brain tumors, high expression of LRIG2 correlates with poor patient survival. Lrig1 and Lrig3 knockout mice are viable, but there have been no reports on Lrig2-deficient mice to date.
METHODOLOGY/PRINCIPAL FINDINGS: Lrig2-deficient mice were generated by the ablation of Lrig2 exon 12 (Lrig2E12). The Lrig2E12-/- mice showed a transiently reduced growth rate and an increased spontaneous mortality rate; 20-25% of these mice died before 130 days of age, with the majority of the deaths occurring before 50 days. Ntv-a transgenic mice with different Lrig2 genotypes were transduced by intracranial injection with platelet-derived growth factor (PDGF) B-encoding replication-competent avian retrovirus (RCAS)-producing DF-1 cells. All injected Lrig2E12+/+ mice developed Lrig2 expressing oligodendroglial brain tumors of lower grade (82%) or glioblastoma-like tumors of higher grade (18%). Lrig2E12-/- mice, in contrast, only developed lower grade tumors (77%) or had no detectable tumors (23%). Lrig2E12-/- mouse embryonic fibroblasts (MEF) showed altered induction-kinetics of immediate-early genes Fos and Egr2 in response to PDGF-BB stimulation. However, Lrig2E12-/- MEFs showed no changes in Pdgfrα or Pdgfrβ levels or in levels of PDGF-BB-induced phosphorylation of Pdgfrα, Pdgfrβ, Akt, or extracellular signal-regulated protein kinases 1 and 2 (ERK1/2). Overexpression of LRIG1, but not of LRIG2, downregulated PDGFRα levels in HEK-293T cells.
CONCLUSIONS: The phenotype of Lrig2E12-/- mice showed that Lrig2 was a promoter of PDGFB-induced glioma, and Lrig2 appeared to have important molecular and developmental functions that were distinct from those of Lrig1 and Lrig3.
Qi XC, Xie DJ, Yan QF, et al.LRIG1 dictates the chemo-sensitivity of temozolomide (TMZ) in U251 glioblastoma cells via down-regulation of EGFR/topoisomerase-2/Bcl-2.
Biochem Biophys Res Commun. 2013; 437(4):565-72 [PubMed
] Related Publications
In the current study, we aimed to understand the potential role of leucine-rich repeats and immunoglobulin-like domains 1 (LRIG1) in TMZ-resistance of U251 glioma cells. We established TMZ-resistant U251 clones (U251/TMZ cells), which expressed low level of LRIG1, but high levels of epidermal growth factor receptor (EGFR), topoisomerase-2 (Topo-2) and Bcl-2. Depletion of LRIG1 by the targeted RNA interference (RNAi) upregulated EGFR/Topo-2/Bcl-2 in U251 cells, and the cells were resistant to TMZ. Reversely, over-expression of LRIG1 in U251 cells downregulated EGFR/Topo-2/Bcl-2 expressions, and cells were hyper-sensitive to TMZ. Our data suggested EGFR-dependent mammalian target of rapamycin (mTOR) activation was important for Topo-2 and Bcl-2 expressions in U251/TMZ cells. The EGFR inhibitor and the mTOR inhibitor downregulated Topo-2/Bcl-2 expressions, both inhibitors also restored TMZ sensitivity in U251/TMZ cells. Finally, inhibition of Topo-2 or Bcl-2 by targeted RNAi(s) knockdown or by the corresponding inhibitor re-sensitized U251/TMZ cells to TMZ, indicating that both Topo-2 and Bcl-2 were important for TMZ resistance in the resistant U251 cells. Based on these results, we concluded that LRIG1 inhibits EGFR expression and the downstream signaling activation, interferes with Bcl-2/Topo-2 expressions and eventually sensitizes glioma cells to TMZ.
Sheu JJ, Lee CC, Hua CH, et al.LRIG1 modulates aggressiveness of head and neck cancers by regulating EGFR-MAPK-SPHK1 signaling and extracellular matrix remodeling.
Oncogene. 2014; 33(11):1375-84 [PubMed
] Related Publications
EGFR overexpression and chromosome 3p deletion are two frequent events in head and neck cancers. We previously mapped the smallest region of recurrent copy-number loss at 3p12.2-p14.1. LRIG1, a negative regulator of EGFR, was found at 3p14, and its copy-number loss correlated with poor clinical outcome. Inducible expression of LRIG1 in head and neck cancer TW01 cells, a line with low LRIG1 levels, suppressed cell proliferation in vitro and tumor growth in vivo. Gene expression profiling, quantitative RT-PCR, chromatin immunoprecipitation, and western blot analysis demonstrated that LRIG1 modulated extracellular matrix (ECM) remodeling and EGFR-MAPK-SPHK1 transduction pathway by suppressing expression of EGFR ligands/activators, MMPs and SPHK1. In addition, LRIG1 induction triggered cell morphology changes and integrin inactivation, which coupled with reduced SNAI2 expression. By contrast, knockdown of endogenous LRIG1 in TW06 cells, a line with normal LRIG1 levels, significantly enhanced cell proliferation, migration and invasiveness. Such tumor-promoting effects could be abolished by specific MAPK or SPHK1 inhibitors. Our data suggest LRIG1 as a tumor suppressor for head and neck cancers; LRIG1 downregulation in cancer cells enhances EGFR-MAPK-SPHK1 signaling and ECM remodeling activity, leading to malignant phenotypes of head and neck cancers.
In baseball parlance, a triple threat is a person who can run, hit and throw with aplomb. Leucine-rich repeats and immunoglobulin-like domains 1 (LRIG1) is a cell surface protein that antagonises ERBB receptor signalling by downregulating receptor levels. Over 10 years ago, Hedman et al postulated that LRIG1 might be a tumour suppressor. Recently, Powell et al provided in vivo evidence substantiating that claim by demonstrating that Lrig1 loss in mice leads to spontaneously arising, highly penetrant intestinal adenomas. Interestingly, Lrig1 also marks stem cells in the gut, suggesting a potential role for Lrig1 in maintaining intestinal epithelial homeostasis. In this review, we will discuss the ability of LRIG1 to act as a triple threat: pan-ERBB negative regulator, intestinal stem cell marker and tumour suppressor. We will summarise studies of LRIG1 expression in human cancers and discuss possible related roles for LRIG2 and LRIG3.
Helicobacter pylori is the strongest known risk factor for the development of gastric adenocarcinoma. H. pylori expresses a repertoire of virulence factors that increase gastric cancer risk, including the cag pathogenicity island and the vacuolating cytotoxin (VacA). One host element that promotes carcinogenesis within the gastrointestinal tract is Krüppel-like factor 5 (KLF5), a transcription factor that mediates key cellular functions. To define the role of KLF5 within the context of H. pylori-induced inflammation and injury, human gastric epithelial cells were co-cultured with the wild-type cag(+) H. pylori strain 60190. KLF5 expression was significantly upregulated following co-culture with H. pylori, but increased expression was independent of the cag island or VacA. To translate these findings into an in vivo model, C57BL/6 mice were challenged with the wild-type rodent-adapted cag(+) H. pylori strain PMSS1 or a PMSS1 cagE(-) isogenic mutant. Similar to findings in vitro, KLF5 staining was significantly enhanced in gastric epithelium of H. pylori-infected compared to uninfected mice and this was independent of the cag island. Flow cytometry revealed that the majority of KLF5(+) cells also stained positively for the stem cell marker, Lrig1, and KLF5(+)/Lrig1(+) cells were significantly increased in H. pylori-infected versus uninfected tissue. To extend these results into the natural niche of this pathogen, levels of KLF5 expression were assessed in human gastric biopsies isolated from patients with or without premalignant lesions. Levels of KLF5 expression increased in parallel with advancing stages of neoplastic progression, being significantly elevated in gastritis, intestinal metaplasia, and dysplasia compared to normal gastric tissue. These results indicate that H. pylori induces expression of KLF5 in gastric epithelial cells in vitro and in vivo, and that the degree of KLF5 expression parallels the severity of premalignant lesions in human gastric carcinogenesis.
Mao F, Wang B, Xiao Q, et al.A role for LRIG1 in the regulation of malignant glioma aggressiveness.
Int J Oncol. 2013; 42(3):1081-7 [PubMed
] Related Publications
The molecular mechanisms that drive the development and aggressive progression of malignant astrocytic tumors remain obscure. Recently, in the search for endogenous negative regulators of EGF receptor, LRIG1 was cloned and characterized as a putative tumor suppressor gene often downregulated in various human tumors, including astrocytic tumors. Although several studies have implicated the function of LRIG1 in the inhibition of tumorigenesis, its precise role and potential underlying mechanisms remain obscure. Therefore, we generated a full-length expression vector to overexpress LRIG1 in the U251 malignant glioma cell line. Introduction of exogenous LRIG1 into glioma cells inhibited cell proliferation manifested by MTT and soft agar clone assay in vitro and subcutaneously tumor xenografts. On the other hand, LRIG1 overexpression inhibited glioma growth by significantly changing the expression pattern of cyclins, resulting in delayed cell cycle. Employing transwell invasion and wound scratch assay and gelatin zymography, LRIG1 inhibited U-251 MG cell invasion and migration by attenuating MMP2 and MMP9 production. Under ligand-stimulated conditions, p-ERK levels did not change, whereas p-AKT levels were inhibited in cells with LRIG1 upregulation, indicating that LRIG1 exerts more inhibiting effects on the PI3K/AKT pathway. Our findings suggest that LRIG1 restricted glioma aggressiveness by inhibiting cell proliferation, migration and invasion. Restoration of LRIG1 to glioma cells could offer a novel therapeutic strategy.
Epidermal growth factor receptor (EGFR) pathway activation is a frequent event in human carcinomas. Mutations in EGFR itself are, however, rare, and the mechanisms regulating EGFR activation remain elusive. Leucine-rich immunoglobulin repeats-1 (LRIG1), an inhibitor of EGFR activity, is one of four genes identified that predict patient survival across solid tumour types including breast, lung, melanoma, glioma, and bladder. We show that deletion of Lrig1 is sufficient to promote murine airway hyperplasia through loss of contact inhibition and that re-expression of LRIG1 in human lung cancer cells inhibits tumourigenesis. LRIG1 regulation of contact inhibition occurs via ternary complex formation with EGFR and E-cadherin with downstream modulation of EGFR activity. We find that LRIG1 LOH is frequent across cancers and its loss is an early event in the development of human squamous carcinomas. Our findings imply that the early stages of squamous carcinoma development are driven by a change in amplitude of EGFR signalling governed by the loss of contact inhibition.
Muller S, Lindquist D, Kanter L, et al.Expression of LRIG1 and LRIG3 correlates with human papillomavirus status and patient survival in cervical adenocarcinoma.
Int J Oncol. 2013; 42(1):247-52 [PubMed
] Related Publications
The incidence of cervical adenocarcinoma, which accounts for 10-20% of all cervical cancers, has increased continuously in developed countries during the last two decades, unlike squamous cell cervical carcinoma. This increasing trend, noted particularly among women under the age of 40 years, has occurred despite extensive cytological Pap smear screening. A deeper understanding of the etiology of cervical adenocarcinoma, better preventive measures and reliable prognostic markers are urgently needed. The human leucine-rich repeats and immunoglobulin-like domains (LRIG) gene family includes: LRIG1, LRIG2 and LRIG3. LRIG expression has proven to be of prognostic value in different types of human cancers, including breast cancer, early stage invasive squamous cervical cancer, cutaneous squamous cell carcinoma, oligodendroglioma and astrocytoma. LRIG1 functions as a tumor suppressor, while less is known about the functions of LRIG2 and LRIG3. This study evaluated the expression of the three LRIG proteins in tumor specimens from 86 women with pure cervical adenocarcinoma by immunohistochemistry. Possible correlations between LRIG expression and known prognostic factors, including human papillomavirus (HPV) status, FIGO stage and histology were investigated. Patient survival data were collected retrospectively and the possible prognostic value of LRIG protein expression was investigated. High staining intensity of LRIG1 and high fraction of LRIG3-positive cells were significantly associated with patient survival, and positive correlations were found between LRIG1 and LRIG3 staining intensity and HPV status. Thus, the LRIG proteins may be important determinants of cervical adenocarcinoma progression and their diagnostic and prognostic potential should be studied further.
Xie R, Yang H, Xiao Q, et al.Downregulation of LRIG1 expression by RNA interference promotes the aggressive properties of glioma cells via EGFR/Akt/c-Myc activation.
Oncol Rep. 2013; 29(1):177-84 [PubMed
] Related Publications
The LRIG1 [leucine-rich repeats and immunoglobulin-like domains (LRIG)] gene is not universally downregulated in human cancers, and its role in tumorigenesis and the development of glioma has not been well addressed. In this study, we used short hairpin RNA (shRNA)-triggered RNA interference (RNAi) to block LRIG1 gene expression in the GL15 human glioma cell line. Specific downregulation of LRIG1 by shRNA resulted in significantly enhanced capabilities of proliferation, inhibition of apoptosis and invasion in the GL15 cells. LRIG1 repression induced marked activation of epidermal growth factor receptor (EGFR), protein kinase B (Akt) and c-Myc signaling molecules. Our results demonstrated that RNAi against LRIG1 may effectively downregulate LRIG1 gene expression. LRIG1 functions as a tumor suppressor in the pathogenesis of glioma via EGFR/Akt/c-Myc activation.
BACKGROUND: Previous studies have revealed altered expression of epidermal growth factor receptor (EGFR)-family members and their endogenous inhibitor leucine-rich and immunoglobulin-like domains 1 (LRIG1) in renal cell carcinoma (RCC). In this study, we analyzed the gene expression levels of EGFR-family members and LRIG1, and their possible associations with clinical parameters in various types of RCC.
METHODS: Gene expression levels of EGFR-family members and LRIG1 were analyzed in 104 RCC samples, including 81 clear cell RCC (ccRCC), 15 papillary RCC (pRCC), and 7 chromophobe RCC (chRCC) by quantitative real-time RT-PCR. Associations between gene expression levels and clinical data, including tumor grade, stage, and patient survival were statistically assessed.
RESULTS: Compared to kidney cortex, EGFR was up-regulated in ccRCC and pRCC, LRIG1 and ERBB2 were down-regulated in ccRCC, and ERBB4 was strongly down-regulated in all RCC types. ERBB3 expression did not differ between RCC types or between RCC and the kidney cortex. The expression of the analyzed genes did not correlate with patient outcome.
CONCLUSIONS: This study revealed that the previously described up-regulation of EGFR and down-regulation of ERBB4 occurred in all analyzed RCC types, whereas down-regulation of ERBB2 and LRIG1 was only present in ccRCC. These observations illustrate the need to evaluate the different RCC types individually when analyzing molecules of interest and potential biological markers.
Mao F, Wang B, Xi G, et al.Effects of RNAi-mediated gene silencing of LRIG1 on proliferation and invasion of glioma cells.
J Huazhong Univ Sci Technolog Med Sci. 2012; 32(2):227-32 [PubMed
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The effects of RNAi-mediated gene silencing of LRlG1 on proliferation and invasion of the human glioma cell line U251-MG and the possible mechanisms were explored in this study. The plasmids pGenesil2-LRIG1-shRNA1 and pGenesil2-LRIG1-shRNA2 were transfected into U251-MG glioma cells respectively by using Lipofectamine 2000 and the transfected cells in which the LRIG1 expression was stably suppressed were selected by G418. The cells transfected with negative shRNA served as control. The expression levels of LRIG1 mRNA and protein were measured by qRT-PCR and Western blotting, respectively. The cell cycle was analyzed by flow cytometry. The results showed that LRIG1 mRNA expression was reduced by 70% and 58% and LRIG1 protein expression by 58% and 26% in U251-MG cells transfected with pGenesil2-LRIG1-shRNAl and pGenesil2-LRIG1-shRNA2 relative to the negative shRNA-transfected U251-MG cells. The proliferative capacity of the LRIG1 specific siRNA-transfected cells was stronger than that of control cells. Cell cycle analysis showed that silencing LRIG1 significantly increased the percentage of S phase cells and the proliferation index (P<0.01). Moreover, silencing LRIG1 could promote the invasion of U251-MG cells (P<0.05). These findings suggested that LRIG1-targeting siRNA can exert a dramatically inhibitory effect on RNA transcription and protein expression of LRIG1, and LRIG1 down-regulation could promote the proliferation of U251-MG cells, arrest U251-MG cells in S phase, and enhance the invasion of U251-MG cells.
Lineage mapping has identified both proliferative and quiescent intestinal stem cells, but the molecular circuitry controlling stem cell quiescence is incompletely understood. By lineage mapping, we show Lrig1, a pan-ErbB inhibitor, marks predominately noncycling, long-lived stem cells that are located at the crypt base and that, upon injury, proliferate and divide to replenish damaged crypts. Transcriptome profiling of Lrig1(+) colonic stem cells differs markedly from the profiling of highly proliferative, Lgr5(+) colonic stem cells; genes upregulated in the Lrig1(+) population include those involved in cell cycle repression and response to oxidative damage. Loss of Apc in Lrig1(+) cells leads to intestinal adenomas, and genetic ablation of Lrig1 results in heightened ErbB1-3 expression and duodenal adenomas. These results shed light on the relationship between proliferative and quiescent intestinal stem cells and support a model in which intestinal stem cell quiescence is maintained by calibrated ErbB signaling with loss of a negative regulator predisposing to neoplasia.
Toriseva M, Ala-aho R, Peltonen S, et al.Keratinocyte growth factor induces gene expression signature associated with suppression of malignant phenotype of cutaneous squamous carcinoma cells.
PLoS One. 2012; 7(3):e33041 [PubMed
] Free Access to Full Article Related Publications
Keratinocyte growth factor (KGF, fibroblast growth factor-7) is a fibroblast-derived mitogen, which stimulates proliferation of epithelial cells. The expression of KGF by dermal fibroblasts is induced following injury and it promotes wound repair. However, the role of KGF in cutaneous carcinogenesis and cancer progression is not known. We have examined the role of KGF in progression of squamous cell carcinoma (SCC) of the skin. The expression of KGF receptor (KGFR) mRNA was lower in cutaneous SCCs (n = 6) than in normal skin samples (n = 6). Expression of KGFR mRNA was detected in 6 out of 8 cutaneous SCC cell lines and the levels were downregulated by 24-h treatment with KGF. KGF did not stimulate SCC cell proliferation, but it reduced invasion of SCC cells through collagen. Gene expression profiling of three cutaneous SCC cell lines treated with KGF for 24 h revealed a specific gene expression signature characterized by upregulation of a set of genes specifically downregulated in SCC cells compared to normal epidermal keratinocytes, including genes with tumor suppressing properties (SPRY4, DUSP4, DUSP6, LRIG1, PHLDA1). KGF also induced downregulation of a set of genes specifically upregulated in SCC cells compared to normal keratinocytes, including genes associated with tumor progression (MMP13, MATN2, CXCL10, and IGFBP3). Downregulation of MMP-13 and KGFR expression in SCC cells and HaCaT cells was mediated via ERK1/2. Activation of ERK1/2 in HaCaT cells and tumorigenic Ha-ras-transformed HaCaT cells resulted in downregulation of MMP-13 and KGFR expression. These results provide evidence, that KGF does not promote progression of cutaneous SCC, but rather suppresses the malignant phenotype of cutaneous SCC cells by regulating the expression of several genes differentially expressed in SCC cells, as compared to normal keratinocytes.
Smac mimetics block inhibitor of apoptosis proteins to trigger TNFα-dependent apoptosis in cancer cells. However, only a small subset of cancer cells seem to be sensitive to Smac mimetics and even sensitive cells can develop resistance. Herein, we elucidated mechanisms underlying the intrinsic and acquired resistance of cancer cells to Smac mimetics. In vitro and in vivo investigations revealed that the expression of the cell surface protein LRIG1, a negative regulator of receptor tyrosine kinases (RTK), is downregulated in resistant derivatives of breast cancer cells sensitive to Smac mimetics. RNA interference-mediated downregulation of LRIG1 markedly attenuated the growth inhibitory activity of the Smac mimetic SM-164 in drug-sensitive breast and ovarian cancer cells. Furthermore, LRIG1 downregulation attenuated TNFα gene expression induced by Smac mimetics and increased the activity of multiple RTKs, including c-Met and Ron. The multitargeted tyrosine kinase inhibitors Crizotinib and GSK1363089 greatly enhanced the anticancer activity of SM-164 in all resistant cell derivatives, with the combination of SM-164 and GSK1363089 also completely inhibiting the outgrowth of resistant tumors in vivo. Together, our findings show that both upregulation of RTK signaling and attenuated TNFα expression caused by LRIG1 downregulation confers resistance to Smac mimetics, with implications for a rational combination strategy.
Wang X, Xiao Q, Xing X, et al.LRIG1 enhances cisplatin sensitivity of glioma cell lines.
Oncol Res. 2012; 20(5-6):205-11 [PubMed
] Related Publications
LRIG family shares similar structures that include a signal peptide, an extracellular region consisting of a leucine-rich repeat domain and three immunoglobulin-like domains, a transmembrane domain, and a cytoplasmic tail. After activation of EGFR, the extracellular LRR domain and immunoglobulin-like domains of LRIG1 can bind to the extracellular parts of EGFR, resulting in recruitment of c-Cbl to the cytoplasmic domains, and induction of EGFR degradation. This study investigated the effects of overexpression of leucine-rich repeats and LRIG1 on cisplatin (CDDP) sensitivity in the glioma cell line U251 and explored the possible mechanisms mediating this effect. We found that CDDP could inhibit the growth of U251 cell line and induced activation of the EGFR. Overexpression of LRIG1 increased the inhibitory effect of CDDP on the U251 cell line via the inhibition of proliferation and induction of apoptosis. The mechanisms underlying the effect of the combined treatment of LRIG1 and CDDP could be that LRIG1 blocked CDDP-induced EGFR activation and regulated the apoptosis proteins. These findings suggest that upregulation of LRIG1 expression enhances the CDDP sensitivity in the glioma cell line U251.
The detection of tumor suppressor gene promoter methylation in sputum-derived exfoliated cells predicts early lung cancer. Here, we identified genetic determinants for this epigenetic process and examined their biologic effects on gene regulation. A two-stage approach involving discovery and replication was used to assess the association between promoter hypermethylation of a 12-gene panel and common variation in 40 genes involved in carcinogen metabolism, regulation of methylation, and DNA damage response in members of the Lovelace Smokers Cohort (N = 1,434). Molecular validation of three identified variants was conducted using primary bronchial epithelial cells. Association of study-wide significance (P < 8.2 × 10(-5)) was identified for rs1641511, rs3730859, and rs1883264 in TP53, LIG1, and BIK, respectively. These single-nucleotide polymorphisms (SNP) were significantly associated with altered expression of the corresponding genes in primary bronchial epithelial cells. In addition, rs3730859 in LIG1 was also moderately associated with increased risk for lung cancer among Caucasian smokers. Together, our findings suggest that genetic variation in DNA replication and apoptosis pathways impacts the propensity for gene promoter hypermethylation in the aerodigestive tract of smokers. The incorporation of genetic biomarkers for gene promoter hypermethylation with clinical and somatic markers may improve risk assessment models for lung cancer.
DNA repair and cell cycle control play an important role in the repair of DNA damage caused by cigarette smoking. Given this role, functionally relevant single nucleotide polymorphisms (SNPs) in genes in these pathways may well affect the risk of smoking-related lung cancer. We examined the relationship between 240 SNPs in DNA repair and cell cycle control pathway genes and lung cancer risk in a case-control study of white current and ex-cigarette smokers (722 cases and 929 controls). Additive, dominant, and recessive genetic models were evaluated for each SNP. A genetic risk summary score was also constructed. Odds ratios (OR) for lung cancer risk and 95% confidence intervals (95% CI) were estimated using logistic regression models. Thirty-eight SNPs were associated with lung cancer risk in our study population at P < 0.05. The strongest associations were observed for rs2074508 in GTF2H4 (P(additive) = 0.003), rs10500298 in LIG1 (P(recessive) = 2.7 × 10(-4)), rs747658 and rs3219073 in PARP1 (rs747658: P(additive) = 5.8 × 10(-5); rs3219073: P(additive) = 4.6 × 10(-5)), and rs1799782 and rs3213255 in XRCC1 (rs1799782: P(dominant) = 0.006; rs3213255: P(recessive) = 0.004). Compared to individuals with first quartile (lowest) risk summary scores, individuals with third and fourth quartile summary score results were at increased risk for lung cancer (OR: 2.21, 95% CI: 1.66-2.95 and OR: 3.44, 95% CI: 2.58-4.59, respectively; P(trend) < 0.0001). Our data suggests that variation in DNA repair and cell cycle control pathway genes is associated with smoking-related lung cancer risk. Additionally, combining genotype information for SNPs in these pathways may assist in classifying current and ex-cigarette smokers according to lung cancer risk.
Lrig1 is the founding member of the Lrig family and has been implicated in the negative regulation of several oncogenic receptor tyrosine kinases including ErbB2. Lrig1 is expressed at low levels in several cancer types but is overexpressed in some prostate and colorectal tumors. Given this heterogeneity, whether Lrig1 functions to suppress or promote tumor growth remains a critical question. Previously, we found that Lrig1 was poorly expressed in ErbB2-positive breast cancer, suggesting that Lrig1 has a growth-inhibitory role in this tumor type. However, breast cancer is a complex disease, with ErbB2-positive tumors accounting for just 25% of all breast cancers. To gain a better understanding of the role of Lrig1 in breast cancer, we examined its expression in estrogen receptor α (ERα)-positive disease which accounts for the majority of breast cancers. We find that Lrig1 is expressed at significantly higher levels in ERα-positive disease than in ERα-negative disease. Our study provides a molecular rationale for Lrig1 enrichment in ERα-positive disease by showing that Lrig1 is a target of ERα. Estrogen stimulates Lrig1 accumulation and disruption of this induction enhances estrogen-dependent tumor cell growth, suggesting that Lrig1 functions as an estrogen-regulated growth suppressor. In addition, we find that Lrig1 expression correlates with prolonged relapse-free survival in ERα-positive breast cancer, identifying Lrig1 as a new prognostic marker in this setting. Finally, we show that ErbB2 activation antagonizes ERα-driven Lrig1 expression, providing a mechanistic explanation for Lrig1 loss in ErbB2-positive breast cancer. This work provides strong evidence for a growth-inhibitory role for Lrig1 in breast cancer.
BACKGROUND: Exposure to estrogens increases the risk of endometrial cancer. Certain estrogen metabolites can form bulky DNA adducts, which are removed via nucleotide excision repair (NER), and the ability to carry out this repair might be related to endometrial cancer risk.
METHODS: We examined 64 tag and functional single-nucleotide polymorphisms (SNPs) in the NER genes ERCC1, ERCC2 (XPD), ERCC3 (XPB), ERCC4 (XPF), ERCC5 (XPG), LIG1, XPA, and XPC in a population-based case-control study in Washington state, with 783 endometrial cancer cases and 795 controls.
RESULTS: The presence of ERCC5 rs4150386 C, LIG1 rs3730865 C, XPA rs2808667 T, or XPC rs3731127 T alleles was associated with risk of endometrial cancer, with respective age-, county-, and reference year-adjusted per-allele ORs and 95% CIs of 0.68 (0.53-0.87, P = 0.002), 1.46 (1.02-2.10, P = 0.04), 0.71 (0.52-0.97, P = 0.03), and 1.57 (1.13-2.17, P = 0.007), respectively.
CONCLUSIONS: Certain ERCC5, LIG1, XPA, and XPC genotypes might influence endometrial cancer risk.
IMPACT: Because of multiple redundancies in DNA repair pathways (and therefore a low prior probability) and the large number of associations examined, false-positive findings are likely. Further characterization of the relation between variation in NER genes and endometrial cancer risk is warranted.
Segatto O, Anastasi S, Alemà SRegulation of epidermal growth factor receptor signalling by inducible feedback inhibitors.
J Cell Sci. 2011; 124(Pt 11):1785-93 [PubMed
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Signalling by the epidermal growth factor receptor (EGFR) controls morphogenesis and/or homeostasis of several tissues from worms to mammals. The correct execution of these programmes requires the generation of EGFR signals of appropriate strength and duration. This is obtained through a complex circuitry of positive and negative feedback regulation. Feedback inhibitory mechanisms restrain EGFR activity in time and space, which is key to ensuring that receptor outputs are commensurate to the cell and tissue needs. Here, we focus on the emerging field of inducible negative feedback regulation of the EGFR in mammals. In mammalian cells, four EGFR inducible feedback inhibitors (IFIs), namely LRIG1, RALT (also known as MIG6 and ERRFI1), SOCS4 and SOCS5, have been discovered recently. EGFR IFIs are expressed de novo in the context of early or delayed transcriptional responses triggered by EGFR activation. They all bind to the EGFR and suppress receptor signalling through several mechanisms, including catalytic inhibition and receptor downregulation. Here, we review the mechanistic basis of IFI signalling and rationalise the function of IFIs in light of gene-knockout studies that assign LRIG1 and RALT an essential role in restricting cell proliferation. Finally, we discuss how IFIs might participate in system control of EGFR signalling and highlight the emerging roles for IFIs in the suppression of EGFR-driven tumorigenesis.
Li F, Ye ZQ, Guo DS, Yang WMSuppression of bladder cancer cell tumorigenicity in an athymic mouse model by adenoviral vector-mediated transfer of LRIG1.
Oncol Rep. 2011; 26(2):439-46 [PubMed
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Previous in vitro studies demonstrated that leucine-rich repeats and immunoglobulin-like domains 1 (LRIG1), a negative regulator of EGFR, is a novel agent for suppressing bladder cancer. However, the role that LRIG1 plays in bladder cancer growth in vivo has not been elucidated in animal or clinical studies. Thus, to evaluate the suppressive effects of LRIG1 on human invasive bladder cancer in vivo, we transferred LRIG1 into athymic mice bearing T24 invasive bladder cancer xenografts mediated by an adenoviral vector. Correlations between LRIG1 expression and tumorigenicity, EGFR expression, xenograft proliferation and angiogenesis were assessed, respectively. The results indicated that tumor volume growth was retarded via Ad-LRIG1 intratumoral injection. In addition LRIG1 upregulation was well correlated with a reduction in EGFR expression and the proliferation rate of xenografts. Furthermore, microvessel densities were reduced and correlated with Ad-LRIG1 administration. No significant macroscopic and microscopic pathological abnormality was observed in the liver, kidney and lungs of Ad-LRIG1-administered mice. This new insight provides evidence that downregulation of EGFR expression by LRIG1 may comprise a potential novel and safe therapeutic approach for improving the prognosis of invasive bladder cancer.
Thomasson M, Wang B, Hammarsten P, et al.LRIG1 and the liar paradox in prostate cancer: a study of the expression and clinical significance of LRIG1 in prostate cancer.
Int J Cancer. 2011; 128(12):2843-52 [PubMed
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The course of prostate cancer varies greatly, and additional prognostic markers are needed. Leucine-rich repeats and immunoglobulin-like domains protein 1 (LRIG1) is an endogenous inhibitor of growth factor signaling and a proposed tumor suppressor. Publicly available gene expression datasets indicate that LRIG1 may be overexpressed in prostate cancer. In our study, the expression of LRIG1 protein in prostate cancer was evaluated for the first time. Immunohistochemistry was performed on tissue microarrays from two different patient series: 355 Swedish patients diagnosed by transurethral resection and 293 American patients who underwent radical prostatectomy. In the Swedish series, high expression of LRIG1 correlated with Gleason score, T-stage, tumor cell proliferation, vascular density and epidermal growth factor receptor (EGFR) phosphorylation. Among the 256 Swedish patients, followed by watchful waiting, high LRIG1 expression was significantly associated with short overall and prostate cancer-specific survival. In contrast, in the US series, high LRIG1 expression was significantly associated with long overall survival. In vitro cell experiments showed that LRIG1 was induced by androgen stimulation, and its expression inhibited prostate cancer cell proliferation. Thus, LRIG1 expression was an independent marker for poor survival in the untreated patient series, perhaps as a secondary marker of androgen receptor and/or EGFR activation. On the contrary, LRIG1 was a marker for good prognosis after prostatectomy, which might be due to its growth inhibiting properties. We propose that LRIG1 is an important determinant of prostate cancer growth, and the implications of its expression on patient outcome depend on the clinical and biological circumstances.
Guillem VM, Cervantes F, Martínez J, et al.XPC genetic polymorphisms correlate with the response to imatinib treatment in patients with chronic phase chronic myeloid leukemia.
Am J Hematol. 2010; 85(7):482-6 [PubMed
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Chronic myeloid leukemia (CML) is driven by the BCR-ABL protein, which promotes the proliferation and viability of the leukemic cells. Moreover, BCR-ABL induces genomic instability that can contribute to the emergence of resistant clones to the ABL kinase inhibitors. It is currently unknown whether the inherited individual capability to repair DNA damage could affect the treatment results. To address this, a comprehensive analysis of single nucleotide polymorphisms (SNPs) on the nucleotide excision repair (NER) genes (ERCC2-ERCC8, RPA1-RPA3, LIG1, RAD23B, XPA, XPC) was performed in 92 chronic phase CML patients treated with imatinib upfront. ERCC5 and XPC SNPs correlated with the response to imatinib. Haplotype analysis of XPC showed that the wild-type haplotype (499C-939A) was associated with a better response to imatinib. Moreover, the 5-year failure free survival for CA carriers was significantly better than that of the non-CA carriers (98% vs. 73%; P = 0.02). In the multivariate logistic model with genetic data and clinical covariates, the hemoglobin (Hb) level and the XPC haplotype were independently associated with the treatment response, with patients having a Hb < or =11 g/dl (Odds ratio [OR] = 5.0, 95% confidence interval [CI] = 1.5-16.1) or a non-CA XPC haplotype (OR = 4.1, 95% CI = 1.6-10.6) being at higher risk of suboptimal response/treatment failure. Our findings suggest that genetic polymorphisms in the NER pathway may influence the results to imatinib treatment in CML.