Differential Expression of Long Non-Coding RNAs MALAT1, ANRIL and MEG3 in Radiation-Exposed Breast Cancer

Breast cancer remains one of the leading causes of mortality among women worldwide. Approximately 80% of patients receive radiotherapy (RT) as part of their treatment. Numerous efforts have been made to distinguish radiosensitive from radioresistant breast tumors. Long non-coding RNAs (lncRNAs) have increasingly been recognized as crucial mediators of cellular responses to radiation among the wide range of biomarkers studied. This study explored the radiation-induced expression changes of three apoptosis-associated lncRNAs-MEG3, MALAT1, and ANRIL-in breast cancer.

In this experimental study, two established human breast cancer cell lines, MCF-7 and MDAMB- 231, were cultured in Dulbecco's Modified Eagle Medium (DMEM) and irradiated with X-rays at doses ranging from 0 to 8 Gy. The expression levels of the lncRNAs ANRIL, MALAT1 and MEG3 were quantified by real-time polymerase chain reaction (PCR). Cell viability in irradiated MCF-7 and MDA-MB-231 cells was evaluated using the MTT colorimetric assay.

Following radiation exposure, the expression levels of ANRIL and MEG3 were significantly decreased (P=0.004) in both MCF-7 and MDA-MB-231 cell lines, whereas MALAT1 expression was significantly increased (P=0.006) only in MDA-MB-231 cells. In addition, cell viability in both MCF-7 and MDA-MB-231 lines declined after irradiation.

Our findings indicate that radiation exposure increases MALAT1 expression while decreasing ANRIL and MEG3 levels, associated with reduced cell viability .These results suggest a potential role for these lncRNAs in radiation-induced cell death.