Significance of MALAT1 long non-coding RNA and miR-20a-5p in regulating epithelial mesenchymal transition in luminal breast cancer patients

Abstract

Background: Luminal breast cancer (LBC) is the most common subtype of breast cancer affecting women worldwide. Although luminal breast cancer typically has a better prognosis, it mostly responds poorly to neoadjuvant chemotherapy. Non-coding RNAs, especially long non-coding RNAs and microRNAs are crucial in regulating biological processes that contribute to breast cancer development. MALAT1, a long non-coding RNA, is pivotal in the progression of breast cancer. Epithelial-mesenchymal transition (EMT) is critical for cell movement during embryonic development. Clarifying this role could pave various avenues for developing innovative strategies for combating this subtype of malignancy. The present study aimed to investigate the expression profiles and clinical relevance of MALAT1 level and EMT-related miRNAs (miR-17-5p, miR-20a-5p, miR-93-5p, miR-135b-5p, and miR-146a-5p) alongside EMT markers (E-cadherin, N-cadherin, vimentin, fibronectin, twist, SNAI1, Slug, ZEB1, and ZEB2) in LBC patients.

Methods: Fresh tissues were collected from fifty patients and twenty noncancerous controls. Differential expression of the markers was evaluated using qRT-PCR assay. Spearman Rho test assessed the relationship between the expression levels. Linear regression test evaluated the correlation between the parameters and various clinico-pathological features.

Results: Our results revealed an overall upregulation of MALAT1 in breast cancer tissues although this increase did not reach statistical significance. Overexpression of miR-20a-5p, miR-135b, and ZEB2 was reported, whereas miR146a-5p, ZEB1 and Vimentin levels were suppressed. Correlation analysis demonstrated that miR-20a-5p was positively correlated with SNAI1, E-cadherin, N-cadherin and Slug also it was significantly associated with family history and tumor laterality.

Conclusions: Our findings suggest that miR-20a-5p plays an oncogenic role in luminal breast cancer by promoting EMT, while MALAT1 may contribute to disease progression through indirect regulatory mechanisms. Finally, MALAT1 and miR-20a-5p might serve as potential therapeutic and prognostic targets in LBC.