Genetic polymorphism of miRNA-196a and its target gene annexin-A1 expression based on ethnicity in Pakistani female breast cancer patients.

Amena Rahim,Muhammad Afzal,Abdul Khaliq Naveed

doi:10.12669/pjms.35.6.1322

Abstract

Objective:To evaluate the association of miR-196a rs11614913 C/T genetic variation and its target gene annexin A1 mRNA expression with breast cancer risk in Pakistani female ethnicities.Methods:This case control study, conducted from March 2017 to November 2018 included 295 breast cancer patients, 295 controls of three Pakistani ethnicities and archived 100 samples of cohort group for genotyping and expression profiling. Genotyping of miR-196a (rs11614913 C/T) was done by ARMS PCR technique. Annexin-A1 (ANXA1) mRNA expression was measured with qRT-PCR and detection of protein expression of ANXA1 was done by immunohistochemistry.Results:CC homozygous genotype of miR-196a rs11614913 was present in 81.4% of cases and 73.9% controls. C/T polymorphism was found to be significantly associated with decrease risk of breast cancer (OR=0.25 (0.11- 0.58, p <0.05). Similar trend was seen with the minor T allele (OR=0.55 (0.39-0.77, p <0.05, and both dominant and recessive models (OR=0.64; p=0.02 and OR=0.26, p=0.00). In the KPK ethnic group significant decrease association with breast cancer risk was observed (OR= 0.22 (0.09-0.53, p < 0.05). Immunohistochemical staining showed loss of ANXA1 protein expression in 72 samples, and significant association was observed with pathological type p=0. 00 and triple negative receptor status p=0.03 and with genotypes of miR-196a p=0.00. Increase relative expression of 2.81± .88 by qPCR analysis of ANXA1 mRNA was noted with TT genotype.Conclusions:Our results demonstrate that miR-196a rs11614913 C/T polymorphism is associated with a decreased risk and loss of protein expression in breast cancer in the Pakistani population.

Highlights

Breast carcinoma is the most common cancer among women
Most miRNAs are down regulated in cancer cells and this repression causes cellular transformation which can lead to tumor development and progressionmiR-196a C to T nucleotide substitution in the 3`p end of the mature strand sequence can modify its expression and function and this can lead to increased cancer susceptibility.[3] miR-196a target genes are involved in cell cycle, differentiation and apoptosis
Genotypic frequency between cases and controls: In dominant model, the minor allele T showed a decreased association with breast cancer risk (OR=0.64, 95%confidence interval (CI)=0.43-0.95, p=0.02) and a similar association existed in the recessive model (OR=0.26, 95% CI=0.11-0.59, p= 0.00) and in the allelic model (OR=0.55, 95%CI=0.39-0.77, p=0.00; Table-I)

Summary

Introduction

Breast carcinoma is the most common cancer among women. There are 611,000 breast cancer (BC) deaths each year and it was the 18th leading cause of disability-adjusted life-years in 2017.1 Pakistan is a developing country with low health care investments. In HAQ index, Pakistan is ranked 154th out of 194 countries in the world.[2] MicroRNAs are non-coding 20-22 nucleotide long single stranded RNA molecules. MiR196a acts by targeting ANXA1 and suppressing it, thereby promoting cell proliferation and suppressing apoptosis and this provides evidence for its oncogenic potential.[5] Expression levels of ANXA1 detected in different cancers are not consistent. In certain tumors such as head and neck, esophageal squamous cell and prostate cancers they are down regulated and in others like glioma and oropharngeal cancers they are up regulated.[6]

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Conclusion