Epigenetic Modulations Induction Using DSCR1 Ectopic Expression in Breast Cancer Cells

Zahra Niki Boroujeni,Atefeh Shirkavand,Seyed Ahmad Aleyasin

doi:10.32604/mcb.2019.04366

Abstract

Today, prognosis, diagnosis and treatment of cancers are progressing with non-invasive methods, including investigation and modification of the DNA methylation profile in cancer cells. One of the effective factors in regulating gene expression in mammals is DNA methylation. Methylation alterations of genes by external factors can change the expression of genes and inhibit the cancer. In the present study, we investigated the effect of down syndrome critical region 1 gene (DSCR1) ectopic expression on the methylation status of the BCL-XL, ITGA6, TCF3, RASSF1A, DOK7, VIM and CXCR4 genes in breast cancer cell lines. The effect of DSCR1 ectopic expression on cell viability in MCF7, MDA-MB-468, MDA-MB-231 and MCF10A cell lines was evaluated using MTT assay after the cells treated by lentivirus vectors harboring DSCR1 for 72 hrs. Methylation status of BCL-XL, ITGA6, TCF3, RASSF1A, DOK7, VIM and CXCR4 genes in breast cancer cell lines was assessed by Restriction Enzyme PCR (REP) method. Also, methylation changes of these genes in breast cancer cell lines after treatment by lentivirus vectors harboring DSCR1 for 7 days were analyzed by REP method. To confirm the effect of DSCR1 on methylation of genes, Real-time PCR was performed. The MTT assay results indicated that DSCR1 ectopic expression reduced cell viability in all three human breast cancer cell lines. Our results showed that DSCR1 ectopic expression after 6 days reversed the hypomethylation status of the BCL-XL, ITGA6, TCF3, VIM and CXCR4 genes and hypermethylation of RASSF1A and DOK7 genes. The expression levels of BCL-XL, ITGA6, TCF3, VIM and CXCR4 mRNA significantly reduced (P<0.05) and the expression levels of RASSF1A and DOK7 mRNA significantly increased (P<0.05). Our findings reveal for the first time the impact of DSCR1 ectopic expression on the methylation status of breast cancer cells and identify a novel agent for epigenetic therapy.

Highlights

Cancer is a multi-factorial disease caused by genetic and epigenetic factors include DNA methylation [Hanahan and Weinberg (2011); Ravindra, Tiwari, Sharma et al (2009)]
The aim of this study was to evaluate the effect of Down syndrome critical region 1 gene (DSCR1) ectopic expression on methylation status and expression level of some key oncogenes and tumor suppressor genes in MCF7, MDA-MB-231, MDA-MB-468 breast cancer cells
DSCR1 expression was quantified by real-time PCR in transformed and untransformed cultures compared to B-actin housekeeping gene expressions

Summary

Introduction

Cancer is a multi-factorial disease caused by genetic and epigenetic factors include DNA methylation [Hanahan and Weinberg (2011); Ravindra, Tiwari, Sharma et al (2009)]. Methylation of CpG sites is an epigenetic regulator of gene expression [Vaissière, Sawan and Herceg (2008)]. General changes in the level of methylation are seen as a distinct feature in tumor cells [Spruck, Rideout and Jones (1993)]. Doi:10.32604/mcb.2019.04366 www.techscience.com/mcb oncogenes and hypermethylation of tumor suppressor genes are associated with cancer in numerous studies [Jones and Buckley (1990)]. DNA methylation has been widely considered in the treatment of cancer since epigenetic changes are more likely to be reversed than genetic changes. One of the ways to make epigenetic changes in cancer cells is gene therapy [Stoff-Khalili, Dall and Curiel (2006)]

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