Association Study of Transforming Growth Factor Beta 1 + 29 T/C exon 1 Polymorphism in Breast Cancer Patients from North Indian Population

BACKGROUND

TGFB1 cytokine is involved in normal mammary epithelial development as well as in breast tumorigenesis. It has role in both breast tumor suppression and progression. TGFB1 gene has several single nucleotide polymorphisms (SNPs) many of which modulate the activity of TGFB1. Our aim in this study was to analyze TGFB1 + 29 polymorphism in breast cancer individuals from North Indian population.

METHODS

TGFB1 + 29 T/C polymorphism was analyzed using Sanger sequencing in 285 breast cancer patients and age matched 363 healthy controls from North Indian population. Next, transcript expression of 13 apoptotic genes, TRAIL, DR4, DR5, DcR1, DcR2, Bcl2, cytochrome c, Casp8L, Casp8, FlipS, FlipL, Casp3s and Casp3 were carried out in 77 breast tumor tissues obtained from 77 individuals.

RESULTS

TGFB1 + 29 CC genotype provided protection against the development of breast cancer (P = 0.012). This was mainly attributable to higher age group (> 45 years) women (P = 0.016). Individuals having CC protector genotype showed significantly higher expression of TGFB1 transcript compared to the TT and TC risk genotypes (P = 0.044). Furthermore, we observed that TGFB1 + 29 CC genotype showed increased TRAIL mediated apoptosis via the extrinsic pathway in breast tumor patients with age greater than 45 years (P = 0.027).

CONCLUSION

TGFB1 + 29 homozygous mutant CC genotype is related to protection against breast cancer in North Indian women population greater than 45 years of age.

TGF beta promotes repair of bulky DNA damage through increased ERCC1/XPF and ERCC1/XPA interaction

Transforming growth factor beta (TGFβ) is multifunctional cytokine that is involved in the coordination and regulation of many cellular homeostatic processes. Compromised TGFβ activity has been attributed to promotion of human cancers. Recent studies have identified a role for TGFβ in response to radiation-induced DNA damage, suggesting a link between TGFβ and the DNA damage response with implications for cancer development. In this study, the effects of TGFβ on promoting the repair of bulky DNA damage, through modulation of nucleotide excision repair (NER), were investigated. We show that treatment of cells with exogenous TGFβ leads to enhanced repair of DNA damage formed by polycyclic aromatic hydrocarbons and ultraviolet-C radiation; similarly, cells with constitutively activated endogenous TGFβ signaling show comparable responses. This effect of TGFβ is independent of the cell cycle. The response to TGFβ is decreased in cells that have compromised TGFβ signaling through RNA interference of Smad4 and is decreased in NER-deficient cells and cells with compromised NER through RNA interference of excision repair cross-complementing group 1 (ERCC1). Increased interaction and nuclear localization of ERCC1/xeroderma pigmentosum (XP) F and ERCC1/XPA proteins is observed after TGFβ treatment. Our study represents the first experimental evidence of a role for TGFβ in the repair of bulky DNA damage resulting from promotion of the interaction and localization of repair protein complexes involved in the incision step of NER.

Association of TGF-β1 Polymorphisms with Breast Cancer Risk: A Meta-Analysis of Case-Control Studies †

Reports on the association of TGF-β1 polymorphisms with breast cancer (BC) have been conflicting, inconsistent, inconclusive, and controversial. PubMed, EMBASE, and Google Scholar were used to identify studies on TGF-β1 polymorphisms and BC risk. Data were extracted independently, and of the initial 3043 studies, 39 case-control studies were eligible for inclusion in the meta-analysis. Information from these studies was extracted, and the overall associations of three TGF-β1 polymorphisms (TGF-β1 29>T/C, TGF-β1-509 C/T, and TGF-β1*6A) with BC risk were analyzed using overall allele, homozygous, heterozygous, recessive, and dominant models. None of the three TGF-β1 polymorphisms studied had a significant influence on the development of BC. However, stratified analysis revealed a positive correlation between the TGF-β1 29T>C polymorphism and BC risk according to a heterozygous model of the Asian population (odds ratio (OR) = 1.115, 95% confidence interval (CI) = 1.006–1.237, p = 0.039). Interestingly, this polymorphism was associated with lower odds of BC according to a heterozygous model of the Middle Eastern population (OR = 0.602, 95% CI = 0.375–0.966, p = 0.035). Thus, our analysis of large datasets indicates that the TGF-β1 29T>C polymorphism is significantly associated with BC risk in the Asian population. In contrast, the TGF-β1*6A and TGF-β1-509 C/T polymorphisms failed to show an association with BC.

Transforming growth factor beta 1 polymorphisms and haplotypes associated with breast cancer susceptibility: A case-control study in Tunisian women

Variable association of transforming growth factor beta 1 (TGFβ1) in breast cancer (BC) pathogenesis was documented, and the contribution of specific TGFB1 polymorphisms to the progression of BC and associated features remains poorly understood. We investigated the contribution of TGFB1 rs1800469, rs1800470, rs1800471, and rs1800472 variants and 4-locus TGFB1 haplotypes on BC susceptibility, and pathological presentation of BC subtypes. Study subjects comprised 430 female BC cases, and 498 cancer-free control women. BC-associated pathological parameters were also evaluated for correlation with TGFB1 variants. Results obtained showed that the minor allele frequency (MAF) of rs1800471 (+74G>C) was higher seen in BC cases than in control subjects, and was associated with increased risk of BC. Significant differences in rs1800471 and rs1800469 (-509C>T) genotype distribution were noted between BC cases and controls, which persisted after controlling for key covariates. TGFB1 rs1800472 was positively, while rs1800470 was negatively associated with triple negativity, while rs1800470 positively correlated with menarche, but negatively with tumor size and molecular type, and rs1800469 correlated positively with menstrual irregularity, distant metastasis, nodal status, and hormonotherapy. Heterogeneity in LD pattern was noted between the tested TGFB1 variants. Four-locus (rs1800472-rs1800471-rs1800470-rs1800469) Haploview analysis identified haplotype TGCT to be negatively associated, and haplotypes CGTT and CCCC to be positively associated with BC. This association of CGTT and CCCC, but not TGCT, with BC remained significant after controlling for key covariates. In conclusion, TGFB1 alleles and specific genotypes, and 4-locus TGFB1 haplotypes influence BC susceptibility, suggesting dual association imparted by specific SNP, consistent with dual role for TGFB1 in BC pathogenesis.

Impact of p53 arg72pro SNP on Breast Cancer Risk in North Indian Population

Background:

Genetic changes in p53 gene contribute to breast cancer susceptibility.

Objective and Methods:

A case-control study and a meta-analysis were performed to investigate the role of p53 codon72 SNP with breast cancer susceptibility in Indian women.

Results:

p53 heterozygous arginine variant was associated with decreased risk of breast cancer in total cohort. In meta-analysis, Allelic and GG vs. CC genetic comparison model were found to be associated with breast cancer risk. Moreover, recessive comparison model indicated a protective correlation with breast cancer occurrence.

Conclusion:

The findings of our case-control study and meta-analysis suggest a significant association between p53 Arg72Pro polymorphism and an increased risk of breast cancer in Indian population.

Voltage-gated calcium channels: Novel targets for cancer therapy

Voltage-gated calcium channels (VGCCs) comprise five subtypes: The L-type; R-type; N-type; P/Q-type; and T-type, which are encoded by α₁ subunit genes. Calcium ion channels also have confirmed roles in cellular functions, including mitogenesis, proliferation, differentiation, apoptosis and metastasis. An association between VGCCs, a reduction in proliferation and an increase in apoptosis in prostate cancer cells has also been reported. Therefore, in the present study, the online clinical database Oncomine was used to identify the alterations in the mRNA expression level of VGCCs in 19 cancer subtypes. Overall, VGCC family genes exhibited under-expression in numerous types of cancer, including brain, breast, kidney and lung cancers. Notably, the majority of VGCC family members (CACNA1C, CACNA1D, CACNA1A, CACNA1B, CACNA1E, CACNA1H and CACNA1I) exhibited low expression in brain tumors, with mRNA expression levels in the top 1–9% of downregulated gene rankings. A total of 5 VGCC family members (CACNA1A, CACNA1B, CACNA1E, CACNA1G and CACNA1I) were under-expressed in breast cancer, with a gene ranking in the top 1–10% of the low-expressed genes compared with normal tissue. In kidney and lung cancers, CACNA1S, CACNA1C, CACNA1D, CACNA1A and CACNA1H exhibited low expression, with gene rankings in the top 1–8% of downregulated genes. In conclusion, the present findings may contribute to the development of new cancer treatment approaches by identifying target genes involved in specific types of cancer.