THE ROLE OF MIR-21 SILENCING IN ENHANCING CELLULAR PROLIFERATION AND APOPTOSIS IN MDA-MB-231 BREAST CANCER: IMPLICATIONS FOR PHYSICAL ACTIVITY AND CANCER REHABILITATION

Abstract

Objective: This study explores the role of miR-21 silencing in modulating the proliferation and apoptosis of MDA-MB-231 breast carcinoma cells through the regulation of MEK12 protein levels, with potential implications for exercise-based cancer rehabilitation and physical activity interventions. Methods: Antisense oligonucleotide (ASODN) technology was utilized to inhibit miR-21 expression in breast carcinoma cells. The effects of miR-21 downregulation on cell survival and apoptosis were evaluated, alongside changes in the expression of tumor-suppressor proteins (TIMP-1, Caspase-3) and tumor-proliferation-related proteins (Bcl-2). Hoechst 33258 staining was employed to assess apoptotic activity. Results: Following AS-miR-21 transfection, a significant increase in apoptosis was observed in breast carcinoma cells. The expression of Bcl-2 protein was notably reduced, indicating decreased DNA replication and tumor cell proliferation. Furthermore, Hoechst 33258 staining confirmed enhanced apoptotic activity post-miR-21 downregulation, accompanied by an upregulation of tumor suppressor proteins TIMP-1 and Caspase-3, suggesting potential inhibition of tumor cell proliferation. Conclusion: The findings suggest that miR-21 silencing plays a crucial role in suppressing breast carcinoma cell growth by modulating tumor-suppressor and proliferation-related proteins, thereby inducing apoptosis. These results provide a molecular basis for developing exercise-based rehabilitation strategies aimed at improving cancer prognosis and post-treatment recovery in breast cancer patients. Future research should explore the potential of physical activity interventions in modulating miR-21-related pathways for breast cancer management.