The interaction between MALAT1 target, miR-143-3p, and RALGAPA2 is affected by functional SNP rs3827693 in breast cancer

A higher expression of MALAT1 has been reported in breast cancer. However, more studies are needed to decipher the mechanisms by which this lncRNA imposes its oncogenic effects. In this study, blood and tissue samples were taken from healthy normal and breast cancer subjects. qPCR was used to analyze the gene expression. HRM-PCR method was carried out to genotype the selected samples. Computational analysis was recruited to find novel targets of MALAT1 and miR-143-3p. The data analyses revealed that MALAT1 was up-regulated in breast cancer and could be a distinctive factor to diagnose cancer. The expression of MALAT1 was inversely correlated with miR-143-3p expression in the studied clinical samples. The down-regulation of miR-143-3p was proven in the clinical tumor samples as compared to the healthy controls. A negative correlation of miR-143-3p with its putative target, RALGAPA2 was observed. A functional SNP rs3827693 located within the 3'UTR region of RALGAPA2 mRNA was validated in this study to associate with breast cancer risk. The rs3827693 allele G significantly decreased the breast cancer incidence and augmented the negative correlation between RALGAPA2 and miR-143-3p, presumably through strengthening the interaction between these two transcripts. This study proposed MALAT1 miR-143-3p and miR-143-3p RALGAPA2 axis in breast cancer, whereby the latter can be altered by the clinically functional SNP rs3827693.

ErbB4 3'-UTR Variant (c.*3622A>G) is Associated with ER/PR Negativity and Advanced Breast Cancer

A genetic variant may alter a gene expression level and as a result be associated with pathological characteristics in breast cancer. In this research, the frequency and association of the ErbB4 3'-untranslated region (3'-UTR) variant, rs12471583 (c.*3622A>G) was studied in an Iranian breast cancer patients. In silico assessment was performed to predict the function of the rs12471583 variant located on the 3'-UTR of ErbB4. Furthermore, as a case-control study, this polymorphism was genotyped in 243 breast cancer patients and non-cancerous controls using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. The Armitage's trend test and regular association tests were performed to analyze a possible association between the rs12471583 and risk of breast cancer and its relevant pathological traits. The bioinformatics analysis predicted that the rs12471583 SNP is located on the four miRNA binding sites, including miR-511-5p, miR-4659a-5p, miR-4659b-5p, and miR-6830-3p. According to logistic regression tests, the G allele is negatively associated with ER- (OR = 0.20, 95% C.I. = 0.04-0.93, p = 0.026), PR- (OR = 0.31, 95% C.I. = 0.10-0.98, p = 0.039), ER-/PR- (OR = 0.20, 95% C.I. = 0.04-0.93, p = 0.026), and advanced breast cancer (OR = 0.40, 95% C.I. = 0.18-0.85, p = 0.016). It has been found that ErbB4 expression may be linked to unfavorable outcomes in breast cancer. Likewise, our results suggest that the G allele may strengthen miRNA-ErbB4 binding efficiency and as a result reduce expression of ErbB4. This is a possible explanation for the observed association.

ErbB4 receptor polymorphism 2368A>C and risk of breast cancer

PURPOSE

A number of single nucleotide polymorphisms (SNPs) in EebB4 gene have been studied, which has clarified their impact on breast cancer in different populations. Nevertheless, the importance of rs13423759 in breast cancer has not been studied and its effect remained almost unclear. In this paper, we evaluated the frequency of rs13423759 different alleles in Iranian population and statistically analyzed their association with breast cancer risk.

MATERIALS AND METHODS

Allele-specific Primer PCR (ASP-PCR) was recruited in this study to genotype rs13423759 position in 172 breast cancer and 148 healthy control subjects. The genotypes of control and cases were analyzed statistically to find the association between rs13423759 alleles and breast cancer incidence and its clinicopathological characteristics. In silico studies were performed in order to find the mechanistic viewpoint of rs13423759 alleles in breast cancer.

RESULTS

rs13423759 allele C was shown to be significantly associated with breast cancer risk, HER2 positivity and increased risk of metastasis. Reciprocally, allele A was correlated with the lowered risk of breast cancer. The in silico studies showed that rs13423759 allele C is capable to strengthen the interaction between miR-548as, an oncomiRNA, and ErbB4 mRNA, leading to its lowered concentration in the cells.

CONCLUSION

rs13423759 allele C is significantly associated with the enhanced risk of breast cancer, elevated metastasis and HER2 positivity.

TP53 rs1625895 is Related to Breast Cancer Incidence and Early Death in Iranian Population

Breast cancer as the second most common cancer worldwide tend to be experienced by Iranian women 10 years earlier with a peak incidence at the premenopausal stage. Genetic mutations of TP53 tumor suppressor gene has been shown to be related to early onset of breast cancer. It has been shown already that rs1625895 polymorphic site is related to glioma as well as lung cancer. In this study, we have investigated the role of rs1625895 polymorphism in breast cancer incidence in Iranian women. DNA extraction of 86 breast cancer patients and 96 control individuals have been used for allele-specific primer-PCR and genotyping of allele A and allele G of the TP53 rs1625895. Genotypes frequencies have been shown that GG homozygosis as the most frequent genotype is a significant association with increased risk of breast cancer development in Iranian women (odds ratio = 6, p = 0.002). On the other hand and in comparison to allele G, allele A could cause early death of breast cancer patients by threefolds significantly (p = 0.011). As a conclusion, we show that allele A is the minor allele in both breast cancer patients and also control individuals and major allele G, is related to the increased risk of breast cancer development in Iranian women.

Evaluation of the Expression Level and Hormone Receptor Association of miR-126 in Breast Cancer

Breast cancer is a major cause of cancer-related death in women worldwide. miRNAs are new players of breast tumorigenesis, used as diagnostic and prognostic biomarkers. Among various miRNAs, miR-126 has been proposed to have a tumor suppressive role in HER2 positive cancer. However, to have a better understanding of its role, further validation is required. The aim of this study was evaluating miR-126 expression level in breast cancer tissues and investigating its potential association with HER2, estrogen and progesterone receptors. miR-126 expression level was measured in 108 specimens including 78 malignant and 30 normal samples using RT-qPCR. The outcome was statistically analyzed. In silico studies were performed to find the potential mechanism of action, through which miR-126 imposes its function. Down-regulation of miR-126 was observed in tumor samples, as compared to the matched normal tissues. Down-regulation of miR-126 was also associated significantly with the absence of estrogen receptor in malignant samples. No association between miR-126 expression and HER2 status was observed. Our in silico analyses showed the possible role of Crk, PI₃K and Ras proto-oncogenes in breast cancer tumorigenesis. miR-126 is significantly down-regulated in breast cancer tissues. Statistically, it showed no correlation with HER2 positivity. However, the association between lower miR-126 and estrogen receptor negativity was observed.

miR-581-Related Single Nucleotide Polymorphism, rs2641726, Located in MUC4 Gene, is Associated with Gastric Cancer Incidence

MUC4 is aberrantly expressed in several carcinomas including breast, colon, ovarian, lung, prostate, stomach and pancreatic cancers. MUC4 can regulate cell apoptosis negatively and facilitate stomach tumorigenesis. In this research, we aimed to evaluate the possible association between rs2641726 (C > A) polymorphism of MUC4 and gastric cancer risk in the Iranian population. In this case-control study, we collected blood samples from 168 gastric cancer patients and 66 healthy subjects. Allele-specific primer polymerase chain reaction method was applied to genotype rs2641726 in the obtained DNA samples. This study demonstrated that rs2641726 C allele was significantly associated with the incidence of gastric cancer, odds ratio = 3.382, 95% confidence interval: 1.840-6.217 (P < 0.001). Furthermore, the distribution of this risk allele was highly enriched in the samples with stage III. In silico studies revealed that the C allele of rs2641726, located within MUC4 3'UTR, is potential to attenuate the interaction between miR-581 and MUC4 mRNA. This disturbing effect, which might result in higher expression of MUC4 oncoprotein, was proposed for the mechanism of action of the rs2641726 risk allele. rs2641726 C allele is significantly enriched in gastric cancer specimens. The attenuating effect of this allele on miR-581 and MUC4 interaction might be a potential mechanism of action by which C allele imposes its oncogenic impact.