The Int7G24A variant of transforming growth factor-beta receptor type I is a risk factor for colorectal cancer in the male Spanish population: a case-control study

TGF-β and microRNA Interplay in Genitourinary Cancers

Genitourinary cancers (GCs) include a large group of different types of tumors localizing to the kidney, bladder, prostate, testis, and penis. Despite highly divergent molecular patterns, most GCs share commonly disturbed signaling pathways that involve the activity of TGF-β (transforming growth factor beta). TGF-β is a pleiotropic cytokine that regulates key cancer-related molecular and cellular processes, including proliferation, migration, invasion, apoptosis, and chemoresistance. The understanding of the mechanisms of TGF-β actions in cancer is hindered by the "TGF-β paradox" in which early stages of cancerogenic process are suppressed by TGF-β while advanced stages are stimulated by its activity. A growing body of evidence suggests that these paradoxical TGF-β actions could result from the interplay with microRNAs: Short, non-coding RNAs that regulate gene expression by binding to target transcripts and inducing mRNA degradation or inhibition of translation. Here, we discuss the current knowledge of TGF-β signaling in GCs. Importantly, TGF-β signaling and microRNA-mediated regulation of gene expression often act in complicated feedback circuits that involve other crucial regulators of cancer progression (e.g., androgen receptor). Furthermore, recently published in vitro and in vivo studies clearly indicate that the interplay between microRNAs and the TGF-β signaling pathway offers new potential treatment options for GC patients.

Association of genetic polymorphisms in interferon-γ, interleukin-6 and transforming growth factor-β1 gene with oral lichen planus susceptibility

BACKGROUND

Oral lichen planus (OLP) is a premalignant mucocutaneous disease in which genetic factors and immune responses play a major role. Cytokines play an important role in the pathogenesis and disease progression of OLP. The aim of this study was to investigate the impact of gene polymorphisms of T helper cell subtype Th1 and Th2 cytokines, interferon-gamma (IFN-γ), interleukin-6 (IL-6) and transforming growth factor (TGF)-β1 on OLP susceptibility in a Saudi cohort.

METHODS

Forty two unrelated patients with OLP and 195 healthy controls were genotyped for IFN-γ (874A/T), IL-6 (174G/C) and TGF-β1 (509C/T) polymorphisms.

RESULTS

The frequency of genotype AT of IFN-γ (874A/T) was significantly higher while genotype AA was lower in OLP patients as compared to controls (P < 0.05). The frequency of T containing genotypes (AT + TT) was also higher in OLP patients as compared to that in controls (P = 0.003). The frequencies of allele T was higher while that of allele A lower in patients than the controls however the difference was not statistically significant (P = 0.07). There was no significant difference in the frequencies of alleles and genotypes of IL-6 (174G/C) and TGF-β1 (509C/T) polymorphisms between patient and control groups. These results indicated that genotype AT of IFN-γ (874A/T) polymorphism is associated with OLP risk and genotype AA is protective to OLP. On the other hand the polymorphisms IL-6 (174G/C) and TGF-β1 (509C/T) may not be associated with OLP risk in our population.

CONCLUSION

It is concluded that IFN-γ (874A/T) polymorphism is associated with the susceptibility of OLP, however further studies with large sample size involving different ethnic populations should be conducted to strengthen our results.

Association between Int7G24A rs334354 polymorphism and cancer risk: a meta-analysis of case-control studies

Accumulating evidences have suggested the potential association between Int7G24A (rs334354) polymorphism and cancer risk. However, results from epidemiological studies are controversial. We thus conducted this meta-analysis to clarify the association. Relevant studies were identified on electronic databases according to the inclusion criteria. A total of 13 case-control studies containing 4092 cases and 5909 controls were included in our meta-analysis. Odds ratios (ORs) with 95% confidence intervals (CIs) were applied to assess the association. The results of the overall population had suggested that Int7G24A polymorphism had an increased risk for cancer, reaching significant levels in the 2 genetic models (allele model, OR = 1.25, 95% CI 1.09-1.42, P = 0.001; dominant model, OR = 1.24, 95% CI 1.06-1.46, P < 0.008). Besides, significant association was found among Asian population (allele model, OR = 1.27, 95% CI 1.11-1.45, P < 0.001; dominant model, OR = 1.28, 95% CI 1.11-1.49, P < 0.001), whereas there was non-significant relationship detected among Caucasian population (allele model, OR = 1.08, 95% CI 0.92-1.26, P = 0.352; dominant model, OR = 1.05, 95% CI 0.87-1.26, P = 0.639). The present meta-analysis had suggested that Int7G24A polymorphism of gene TGFBR1 involved in the transforming growth factor beta (TGF-β) signaling pathway had a significantly increased risk for cancer development.

Changes in the transcriptional profile in response to overexpression of the osteopontin-c splice isoform in ovarian (OvCar-3) and prostate (PC-3) cancer cell lines

Background

Especially in human tumor cells, the osteopontin (OPN) primary transcript is subject to alternative splicing, generating three isoforms termed OPNa, OPNb and OPNc. We previously demonstrated that the OPNc splice variant activates several aspects of the progression of ovarian and prostate cancers. The goal of the present study was to develop cell line models to determine the impact of OPNc overexpression on main cancer signaling pathways and thus obtain insights into the mechanisms of OPNc pro-tumorigenic roles.

Methods

Human ovarian and prostate cancer cell lines, OvCar-3 and PC-3 cells, respectively, were stably transfected to overexpress OPNc. Transcriptomic profiling was performed on these cells and compared to controls, to identify OPNc overexpression-dependent changes in gene expression levels and pathways by qRT-PCR analyses.

Results

Among 84 genes tested by using a multiplex real-time PCR Cancer Pathway Array approach, 34 and 16, respectively, were differentially expressed between OvCar-3 and PC-3 OPNc-overexpressing cells in relation to control clones. Differentially expressed genes are included in all main hallmarks of cancer, and several interacting proteins have been identified using an interactome network analysis. Based on marked up-regulation of Vegfa transcript in response to OPNc overexpression, we partially validated the array data by demonstrating that conditioned medium (CM) secreted from OvCar-3 and PC-3 OPNc-overexpressing cells significantly induced endothelial cell adhesion, proliferation and migration, compared to CM secreted from control cells.

Conclusions

Overall, the present study elucidated transcriptional changes of OvCar-3 and PC-3 cancer cell lines in response to OPNc overexpression, which provides an assessment for predicting the molecular mechanisms by which this splice variant promotes tumor progression features.

Int7G24A polymorphism (rs334354) and cancer risk

INTRODUCTION

The transforming growth factor β (TGF-β) signaling system plays an important role in carcinogenesis. Alteration of TGF-β receptors is a potential mechanism in the development and progression of human cancers. Several studies have investigated the association between TGFBR1 gene Int7G24A and cancer risk, but the results are still inconclusive, so a meta-analysis is needed to verify the association.

MATERIAL AND METHODS

We carried out a literature search using the PubMed database (up to January 2012) to identify all papers that investigated the association between the Int7G24A polymorphism (rs334354) and cancer risk. The inclusion criteria were: (1) evaluation of the Int7G24A polymorphism and cancer risk, (2) case-control studies, (3) sufficient published data about genotype frequency. Also the strength of the association between Int7G24A polymorphism and cancer was measured by odds ratio (OR), which was calculated according to the method of Woolf. A χ(2)-based Q statistic test was performed to assess the between-study heterogeneity.

RESULTS

There are 10 studies including 2398 cases and 3465 controls in the research. Our results indicate that the TGFBR1 gene Int7G24A polymorphism is associated with cancer risk (A vs. G: OR = 1.35, 95% CI = 1.10-1.66, A/A+G/A vs. G/G: OR = 1.34, 95% CI = 1.05-1.72).

CONCLUSIONS

This meta-analysis suggests that the TGFBR1 gene Int7G24A polymorphism might be associated with an increased risk of cancer.

Molecular characterization of TGF-β type I receptor gene (Tgfbr1) in Chlamys farreri, and the association of allelic variants with growth traits

BACKGROUND

Scallops are an economically important aquaculture species in Asian countries, and growth-rate improvement is one of the main focuses of scallop breeding. Investigating the genetic regulation of scallop growth could benefit scallop breeding, as such research is currently limited. The transforming growth factor beta (TGF-β) signaling through type I and type II receptors, plays critical roles in regulating cell proliferation and growth, and is thus a plausible candidate growth regulator in scallops.

RESULTS

We cloned and characterized the TGF-β type I receptor (Tgfbr1) gene from Zhikong scallops (Chlamys farreri). The deduced amino acid sequence contains characteristic residues and exhibits the conserved structure of Tgfbr1 proteins. A high expression level of scallop Tgfbr1 was detected during early embryonic stages, whereas Tgfbr1 expression was enriched in the gonad and striated muscle in adults. A single nucleotide polymorphism (SNP, c. 1815C>T) in the 3' UTR was identified. Scallops with genotype TT had higher growth traits values than those with genotype CC or CT in a full-sib family, and significant differences were found between genotypes CC and TT for shell length, shell height, and striated muscle weight. An expression analysis detected significantly more Tgfbr1 transcripts in the striated muscle of scallops with genotype CC compared to those with genotype TT or CT. Further evaluation in a population also revealed higher striated muscle weight in scallops with genotype TT than those with the other two genotypes. The inverse correlation between striated muscle mass and Tgfbr1 expression is consistent with TGF-β signaling having a negative effect on cell growth.

CONCLUSION

The scallop Tgfbr1 gene was cloned and characterized, and an SNP potentially associated with both scallop growth and Tgfbr1 expression was identified. Our results suggest the negative regulation of Tgfbr1 in scallop growth and provide a candidate marker for Zhikong scallop breeding.

Association between TGFBR1 polymorphisms and cancer risk: a meta-analysis of 35 case-control studies

Background

Numerous epidemiological studies have evaluated the association between TGFBR1 polymorphisms and the risk of cancer, however, the results remain inconclusive. To derive a more precise estimation of the relation, we conducted a comprehensive meta-analysis of all available case-control studies relating the TGFBR1*6A and IVS7+24G>A polymorphisms of the TGFBR1 gene to the risk of cancer.

Methods

Eligible studies were identified by search of electronic databases. Overall and subgroup analyses were performed. Odds ratio (OR) and 95% confidence interval (CI) were applied to assess the associations between TGFBR1*6A and IVS7+24G>A polymorphisms and cancer risk.

Results

A total of 35 studies were identified, 32 with 19,767 cases and 18,516 controls for TGFBR1*6A polymorphism and 12 with 4,195 cases and 4,383 controls for IVS7+24G>A polymorphism. For TGFBR1*6A, significantly elevated cancer risk was found in all genetic models (dominant OR = 1.11, 95% CI = 1.04∼1.18; recessive: OR = 1.36, 95% CI = 1.11∼1.66; additive: OR = 1.13, 95% CI = 1.05∼1.20). In subgroup analysis based on cancer type, increased cancer risk was found in ovarian and breast cancer. For IVS7+24G>A, significant correlation with overall cancer risk (dominant: OR = 1.39, 95% CI = 1.15∼1.67; recessive: OR = 2.23, 95% CI = 1.26∼3.92; additive: OR = 1.43, 95% CI = 1.14∼1.80) was found, especially in Asian population. In the subgroup analysis stratified by cancer type, significant association was found in breast and colorectal cancer.

Conclusions

Our investigations demonstrate that TGFBR1*6A and IVS7+24G>A polymorphisms of TGFBR1 are associated with the susceptibility of cancer, and further functional research should be performed to explain the inconsistent results in different ethnicities and cancer types.

Debate about TGFBR1 and the susceptibility to colorectal cancer

Recent years have witnessed enormous progress in our understanding of the genetic predisposition to colorectal cancer (CRC). Estimates suggest that all or most genetic susceptibility mechanisms proposed so far, ranging from high-penetrance genes to low-risk alleles, account for about 60% of the population-attributable fraction of CRC predisposition. In this context, there is increasing interest in the gene encoding the transforming growth factor β receptor 1 (TGFBR1); first when over a decade ago a common polymorphism in exon 1 (rs11466445, TGFBR1*6A/9A) was suggested to be a risk allele for CRC, then when linkage studies identified the chromosomal region where the gene is located as susceptibility locus for familial CRC, and more recently when the allele-specific expression (ASE) of the gene was proposed as a risk factor for CRC. Published data on the association of TGFBR1 with CRC, regarding polymorphisms and ASE and including sporadic and familial forms of the disease, are often contradictory. This review gives a general overview of the most relevant studies in order to clarify the role of TGFBR1 in the field of CRC genetic susceptibility.

The association of polymorphisms on TGFBR1 and colorectal cancer risk: a meta-analysis

Epidemiological studies found inconsistent results on the association of two variants on TGFBR1 (TGFBR1*6A and Int7G24A) with colorectal cancer (CRC) risk. The present study was aimed to evaluate the association of these two variants with CRC susceptibility via the meta-analysis methods. For variant TGFBR1*6A, nine reports including 6,765 CRC patients and 8,496 unrelated controls were identified. The heterozygotes *6A/*9A showed a significant increased risk of CRC with the pooled OR was 1.12 (95% CI = 1.02-1.23), and the pooled OR for the homozygotes *6A/*6A was 1.13 (95% CI = 0.80-1.58) compared to the homozygotes *9A/*9A. However, under the dominant effect model, the TGFBR1*6A carriers showed a significantly increased CRC risk (pooled OR = 1.12, 95% CI = 1.03-1.23, *6A/*6A and *6A/*9A vs. *9A/*9A). For variant Int7G24A, three case-control studies with 1,074 cases and 1,945 controls were found. Although no significant association was found for heterozygosity Int7G24A carriers with CRC risk (pooled OR = 0.97, 95% CI = 0.67-1.42), the homozygosity A/A carriers showed a significant elevated risk of CRC (pooled OR = 1.68, 95% CI = 1.14-2.47) compared to G/G homozygotes. Under the recessive effect model, homozygotes A/A showed a 71% increase of CRC risk compared to the A/G and G/G genotype carriers (pooled OR = 1.71, 95% CI = 1.17-2.51). These data strongly suggested that the two polymorphisms of TGFBR1 may confer low-penetrance susceptibility of CRC risk.

Association of polymorphisms in transforming growth factor-β receptors with susceptibility to gastric cardia adenocarcinoma

Both transforming growth factor-β receptor I (TGFBR1) and receptor II (TGFBR2) are serine/threonine kinases and play important roles in TGF-β/Smads signal pathway. The case-control study was performed to evaluate the possible association of Int7G24A and *6A polymorphisms of TGFBR1 and G-875A polymorphism of TGFBR2 with susceptibility to gastric cardia adenocarcinoma (GCA) in a population of North China. Polymerase-chain reaction (PCR)-restriction fragment length polymorphism (RFLP) and PCR methods were used respectively to detect the genotype of Int7G24A, *6A and G-875A in 468 GCA and 584 healthy controls. Immunohistochemistry method was used to determine the protein expression of TGFBR1 and TGFBR2. Family history of upper gastrointestinal cancer (UGIC) significantly increased the risk of developing GCA. There were no differences in the genotype distribution of TGFBR1 *6A polymorphism among cases and controls. However, A allele of Int7G24A significantly elevated the risk of developing GCA (adjusted OR = 1.34, 95% CI 1.03-1.87) and A allele of G-875A significantly decreased the risk of developing GCA (adjusted OR = 0.73, 95% CI 0.49-0.92). When stratified for TNM stage, A allele of Int7G24A and G-875A allele carriers had a 1.41-fold (95% CI 1.05-1.98) increased and a 0.70-fold (95% CI 0.47-0.92) decreased risk of stage III and IV gastric cardia adenocarcinoma. The protein expression of TGFBR1 and TGFBR2 in GCA was not correlated with genotypes of them. In conclusions, TGFBR1 Int7G24A and TGFBR2 G-875A polymorphisms may play important roles in the risk of GCA in North China.

TGFBR1 signaling and breast cancer

Over the past decade mutations discovered in genes such as BRCA1, BRCA2, TP53 and PTEN, have emerged as high-penetrance susceptibility genes and are clinically relevant for determination of breast cancer risk. Genetic counseling and subsequent screening for mutations and gene rearrangement has improved patient outcome through early detection and prophylactic interventions in patients with familial breast cancer syndromes. However, these high-penetrance genes only account for a small fraction of the hereditary linked breast cancers. It is currently believed that low-penetrance susceptibility alleles and/or environmental factors may play an important role in the remaining cases. TGFBR1*6A (*6A) is a common hypomorphic variant of the type I TGF-β receptor gene (TGFBR1) that has been associated with risk for several forms of cancer, in particular breast cancer. Several epidemiological studies have suggested that patients who carry the *6A allele have an increased risk of breast cancer. Furthermore, functional analysis suggests that this mutation alters TGF-β signaling and promotes tumorigenesis. Although a decade of research has provided basic information in regards to the prevalence of this mutation in several cancer types and populations the molecular underpinning of its functional effects are poorly understood. A better understanding of the molecular mechanism of TGFBR1 signaling in breast cancer may have an impact on breast cancer risk assessment and breast cancer prevention.