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

Inhibitors of TGFβR1/ALK4/JNK3/Flt1 Kinases in Cynomolgus Macaques Lead to the Rapid Induction of Renal Epithelial Tumors

Two young cynomolgus macaques (Macaca fascicularis) given a small molecule kinase inhibitor ((S)-4-((2-(5-chloro-2-fluorophenyl)-5-isopropylpyrimidin-4-yl)amino)-N-(2-hydroxypropyl)nicotinamide [SCIO-120]) via nasogastric intubation gavage, once-daily for 21 days at 400 mg/kg/day, developed an unusual epithelial proliferative process in the renal parenchyma. Morphological and immunohistochemical characterization of the lesions confirmed an invasive malignant epithelial neoplasm (carcinoma). A similar renal neoplasm was seen in a third macaque after a 14-day exposure to a second kinase inhibitor in the same chemical series ((S) 4-((2-(5-chloro-2-fluorophenyl)-5-methoxypyrimidin-4-yl)amino)-N-cyclopropylnicotinamide [SCIO-974]). Despite remarkably short latency periods, exposure to these kinase inhibitors was likely causally associated with the induction of the renal tumors, as renal carcinomas are exceedingly rare spontaneously in macaques. Both SCIO-120 and SCIO-974 were designed as potent TGFβR1 inhibitors (IC50s 37 and 39 nM, respectively). SCIO-120 and SCIO-974 inhibited additional kinases, most notably closely related ALK4 (IC50 = 34  and 20 nM, respectively), c-Jun n-Terminal kinase 3 (JNK3, IC50 = 10 and 20 nM, respectively), and Fms-related tyrosine kinase 1 (29  and 76 nM, respectively). TGFβR1 has been specifically implicated in epithelial proliferative disorders, including neoplasia. Neither SCIO-120 nor SCIO-974 was genotoxic based on bacterial reverse mutation and/or clastogenicity screening assays. The rapid appearance of renal carcinomas in primates following short-term treatment with nongenotoxic kinase inhibitors is remarkable and suggests that the compounds had noteworthy tumor-enhancing effects, hypothetically linked to their TGFβR1 inhibition activity. These observations have implications for mechanisms of carcinogenesis and TGFβR1 biology.

A genetic variant located in the miR-532-5p-binding site of TGFBR1 is associated with the colorectal cancer risk

BACKGROUND

Genome-wide association studies have identified genes in the transforming growth factor-β (TGFβ) signaling pathway that are responsible for regulating carcinogenesis.

METHODS

We searched for single-nucleotide polymorphisms (SNPs) located within 3'-untranslated regions (3'-UTRs) that might affect the ability of miRNAs to bind genes in the TGFβ pathway for further analysis. We used TaqMan technology to genotype these SNPs in a population-based case-control study of 1147 colorectal cancer patients and 1203 matched controls in a Chinese population.

RESULTS

The rs1590 variant of TGFBR1 exhibited a significant association with colorectal cancer risk. Compared with individuals carrying the rs1590 TT genotype, individuals carrying the GT/GG genotypes had a decreased risk of colorectal cancer [odd ratio (OR) = 0.82, 95% confidence interval (CI) = 0.68-0.97], which was more evident among older individuals with a family history of cancer. Luciferase assays confirmed that the rs1590 T allele altered the capacity of miR-532-5p to bind TGFBR1.

CONCLUSIONS

Based on these findings, the rs1590 variant in the 3'-UTR of TGFBR1 may contribute to the susceptibility to colorectal cancer, predominantly by altering miR-532-5p binding.

TGFBR1*6A is a potential modifier of migration and invasion in colorectal cancer cells

Type 1 transforming growth factor β receptor (TGFBR1)*6A, a common hypomorphic variant of TGFBR1, may act as a susceptibility allele in colorectal cancer. However, the contribution of TGFBR1*6A to colorectal cancer development is largely unknown. To test the hypothesis that TGFBR1*6A promotes colorectal cancer invasion and metastasis via Smad-independent transforming growth factor-β (TGF-β) signaling, the effect of TGFBR1*6A on the invasion of colorectal cancer cells was assessed. pCMV5-TGFBR1*6A-HA plasmids were transfected into SW48 and DLD-1 cells by Lipofectamine-mediated DNA transfection. The effect of TGF-β1 on the proliferation of SW48 and DLD-1 cells transfected with TGFBR1*6A was determined by MTT assay. The effects of the TGF-β1 on the invasion of the transfected SW48 and DLD-1 cells were determined using Matrigel-coated plates. Transforming migrating chambers were used to determine the effects of TGF-β1 on the migration of the transfected SW48 and DLD-1 cells. Western blot analysis was used to determine the expression of phosphorylated (p-) extracellular-signal-regulated kinase (ERK), p-P38 and p-SMAD family member 2 in SW48 cells. Using transfected TGFBR1*6A SW48 and DLD-1 cell lines our group demonstrated that, in comparison with TGFBR1*9A, TGFBR1*6A is capable of switching TGF-β1 growth-inhibitory signals into growth-stimulatory signals which significantly increased the invasion of SW48 and DLD-1 cells. Functional assays indicated that TGFBR1*6A weakened Smad-signaling but increased ERK and p38 signaling, which are crucial mediators of cell migration and invasion. From this, it was possible to conclude that TGFBR1*6A enhanced SW48 cell migration and invasion through the mitogen-activated protein kinase pathway and that it may contribute to colorectal cancer progression in a TGF-β1/Smad signaling-independent manner. This suggests that TGFBR1*6A may possess oncogenic properties and that it may affect the migration and invasion of colorectal cancer cells.

Associations of TGFBR1 and TGFBR2 gene polymorphisms with the risk of hypospadias: a case-control study in a Chinese population

This case-control study investigated the association of transforming growth factor-β (TGF-β) receptor type I and II (TGFBR1 and TGFBR2) gene polymorphisms with the risk of hypospadias in a Chinese population. One hundred and sixty two patients suffering from hypospadias were enrolled as case group and 165 children who underwent circumcision were recruited as control group. Single nucleotide polymorphisms (SNPs) in TGFBR1 and TGFBR2 genes were selected on the basis of genetic data obtained from HapMap. PCR-restriction fragment length polymorphism (PCR-RFLP) was performed to identify TGFBR1 and TGFBR2 gene polymorphisms and analyze genotype distribution and allele frequency. Logistic regression analysis was conducted to estimate the risk factors for hypospadias. No significant difference was found concerning the genotype and allele frequencies of TGFBR1 rs4743325 polymorphism between the case and control groups. However, genotype and allele frequencies of TGFBR2 rs6785358 in the case group were significantly different in contrast with those in the control group. Patients carrying the G allele of TGFBR2 rs6785358 polymorphism exhibited a higher risk of hypospadias compared with the patients carrying the A allele (P<0.05). The TGFBR2 rs6785358 genotype was found to be significantly related to abnormal pregnancy and preterm birth (both P<0.05). The frequency of TGFBR2 rs6785358 GG genotype exhibited significant differences amongst patients suffering from four different pathological types of hypospadias. Logistic regression analysis revealed that preterm birth, abnormal pregnancy, and TGFBR2 rs6785358 were the independent risk factors for hypospadias. Our study provides evidence that TGFBR2 rs6785358 polymorphism might be associated with the risk of hypospadias.

Transforming growth factor-β signaling pathway-associated genes SMAD2 and TGFBR2 are implicated in metabolic syndrome in a Taiwanese population

The transforming growth factor-β (TGF-β) signaling pathway and its relevant genes have been correlated with an increased risk of developing various hallmarks of metabolic syndrome (MetS). In this study, we assessed whether the TGF-β signaling pathway-associated genes of SMAD family member 2 (SMAD2), SMAD3, SMAD4, transforming growth factor beta 1 (TGFB1), TGFB2, TGFB3, transforming growth factor beta receptor 1 (TGFBR1), and TGFBR2 are associated with MetS and its individual components independently, through complex interactions, or both in a Taiwanese population. A total of 3,000 Taiwanese subjects from the Taiwan Biobank were assessed. Metabolic traits such as waist circumference, triglyceride, high-density lipoprotein cholesterol, systolic and diastolic blood pressure, and fasting glucose were measured. Our results showed a significant association of MetS with the two single nucleotide polymorphisms (SNPs) of SMAD2 rs11082639 and TGFBR2 rs3773651. The association of MetS with these SNPs remained significant after performing Bonferroni correction. Moreover, we identified the effect of SMAD2 rs11082639 on high waist circumference. We also found that an interaction between the SMAD2 rs11082639 and TGFBR2 rs3773651 SNPs influenced MetS. Our findings indicated that the TGF-β signaling pathway-associated genes of SMAD2 and TGFBR2 may contribute to the risk of MetS independently and through gene-gene interactions.

TGFBR1*6A polymorphism in sporadic and familial colorectal Carcinoma: a case-control study and systematic literature review

BACKGROUND

The role of genetic factors in colorectal cancer pathogenesis is widely accepted. Polymorphisms are actually thought to play a role in the unexplained colorectal cancer (CRC) susceptibility. There is conflicting data regarding the role of the transforming growth factor beta receptor 1 polymorphism 6A (TGFBR1*6A) in the increased incidence of CRC.

PURPOSE

Our aim is to test the association between this polymorphism and sporadic/familial CRC in the Lebanese population paying attention to lead time bias in the control group. This is a case-control study conducted in two Lebanese hospital centers.

MATERIALS AND METHODS

Cases were diagnosed with CRC during the period of 1 year prior to the study. Controls were healthy subjects aged >50 years with a history of normal colonoscopy during the period of 5 years prior to the beginning of the study. A total of 96 cases (57 sporadic/39 familial) and 97 controls were genotyped. The odds ratios for 6A carrier status was statistically significant for sporadic CRC, odds ratio (OR) = 2.314 (95 % confidence interval (CI) 1.030-5.195) but not for familial CRC.

RESULTS

No association was found between 6A carrier status and mean age at diagnosis of CRC. This is the first article in the literature to evaluate the association between 6A polymorphism and total, sporadic, and familial CRC in a single study with reduction of bias in the control group. Results are in conjunction with other studies and meta-analysis.

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.

Little evidence for association between the TGFBR1*6A variant and colorectal cancer: a family-based association study on non-syndromic family members from Australia and Spain

Background

Genome-wide linkage studies have identified the 9q22 chromosomal region as linked with colorectal cancer (CRC) predisposition. A candidate gene in this region is transforming growth factor β receptor 1 (TGFBR1). Investigation of TGFBR1 has focused on the common genetic variant rs11466445, a short exonic deletion of nine base pairs which results in truncation of a stretch of nine alanine residues to six alanine residues in the gene product. While the six alanine (*6A) allele has been reported to be associated with increased risk of CRC in some population based study groups this association remains the subject of robust debate. To date, reports have been limited to population-based case–control association studies, or case–control studies of CRC families selecting one affected individual per family. No study has yet taken advantage of all the genetic information provided by multiplex CRC families.

Methods

We have tested for an association between rs11466445 and risk of CRC using several family-based statistical tests in a new study group comprising members of non-syndromic high risk CRC families sourced from three familial cancer centres, two in Australia and one in Spain.

Results

We report a finding of a nominally significant result using the pedigree-based association test approach (PBAT; p = 0.028), while other family-based tests were non-significant, but with a p-value <; 0.10 in each instance. These other tests included the Generalised Disequilibrium Test (GDT; p = 0.085), parent of origin GDT Generalised Disequilibrium Test (GDT-PO; p = 0.081) and empirical Family-Based Association Test (FBAT; p = 0.096, additive model). Related-person case–control testing using the “More Powerful” Quasi-Likelihood Score Test did not provide any evidence for association (M_QLS; p = 0.41).

Conclusions

After conservatively taking into account considerations for multiple hypothesis testing, we find little evidence for an association between the TGFBR1*6A allele and CRC risk in these families. The weak support for an increase in risk in CRC predisposed families is in agreement with recent meta-analyses of case–control studies, which estimate only a modest increase in sporadic CRC risk among 6*A allele carriers.

TGF-β: duality of function between tumor prevention and carcinogenesis

Several mechanisms underlying tumor progression have remained elusive, particularly in relation to transforming growth factor beta (TGF-β). Although TGF-β initially inhibits epithelial growth, it appears to promote the progression of advanced tumors. Defects in normal TGF-β pathways partially explain this paradox, which can lead to a cascade of downstream events that drive multiple oncogenic pathways, manifesting as several key features of tumorigenesis (uncontrolled proliferation, loss of apoptosis, epithelial-to-mesenchymal transition, sustained angiogenesis, evasion of immune surveillance, and metastasis). Understanding the mechanisms of TGF-β dysregulation will likely reveal novel points of convergence between TGF-β and other pathways that can be specifically targeted for therapy.

Vascular endothelial growth factor (VEGF) gene polymorphisms and colorectal cancer: a meta-analysis of epidemiologic studies

BACKGROUND

Studies investigating the association between vascular endothelial growth factor (VEGF) polymorphisms and colorectal cancer (CRC) risk report conflicting results. To clarify the effect of four VEGF (-460T/C, -634G/C, +936C/T, and -2578C/A) gene polymorphisms on the risk of developing CRC, we carried out a meta-analysis using published data to obtain more precise estimates of risk.

METHODS

Electronic searches of PubMed and EMBASE were conducted to select studies for this meta-analysis. The principal outcome measure was the odds ratio (OR) with 95% confidence interval (CI) for the risk of CRC associated with four VEGF (-460T/C, -634G/C, +936C/T, and -2578C/A) gene polymorphisms.

RESULTS

We identified 12 epidemiologic studies, which included 2770 CRC cases and 2568 controls. The combined results based on all studies showed that CRC cases had a significantly higher frequency of VEGF -634GG (OR=1.24, 95% CI=1.06, 1.44) and -2578AA (OR=1.37, 95% CI=1.12, 1.66) genotype and a lower frequency of -634CG (OR=0.82, 95% CI=0.71, 0.95) than controls. When stratifying for race, we found that patients with CRC had a significantly higher frequency of -460TC (OR=1.54, 95% CI=1.22, 1.94), -460CC (OR=2.00, 95% CI=1.50, 2.67), and -2578AA (OR=1.38, 95% CI=1.12, 1.69) and a lower frequency of -2578AA (OR=0.78, 95% CI=0.65, 0.93) genotypes of VEGF than controls, among Caucasians. We also found that patients with CRC had a significantly higher frequency of -634GG (OR=1.61, 95% CI=1.20, 2.15) and a lower frequency of -634CG (OR=0.60, 95% CI=0.46, 0.79) genotypes of VEGF than controls, among Asians.

CONCLUSIONS

Our meta-analysis suggests that the VEGF -460T/C, -634G/C, and -2578C/A gene polymorphisms are associated with a risk of CRC.

Association of epidermal growth factor +61 A/G polymorphism in Chinese patients with colon cancer

Epidermal growth factor (EGF) plays an important role in tumorigenesis. The association between the +61 A/G polymorphism of the EGF gene and colon cancer risk remains controversial and unclear. The objective of this study was to investigate the association between EGF +61 A/G polymorphism and colon cancer risk in a Chinese population. A hospital-based case-control study was conducted to assess the possible association between EGF +61 A/G polymorphism and colon cancer risk. A total of 180 colon cancer patients and 180 cancer-free healthy controls were recruited in the Chinese population. Genomic DNA was isolated from peripheral blood, and gene polymorphisms were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Colon cancer patients had a significantly higher frequency of +61 GG genotype (odds ratio [OR]=1.93, 95% confidence interval [CI]=1.07, 3.50; p=0.03) than that of controls. When stratified by the tumor location, tumor size, growth pattern, differentiation, and tumor-node-metastasis (TNM) stage of colon cancer, no statistically significant results were observed. Our study revealed that EGF +61 GG genotype was associated with a higher risk of colon cancer in Chinese population.

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.