Silencing Calumenin Expression via Artificial MicroRNA, a Potential Breakthrough for Inhibiting Proliferation, Halting Migration, and Triggering Apoptosis in Breast Cancer Cells.

Purpose: Calumenin (CALU) is a calcium-binding protein involved in several physiological processes, exhibiting tumor-specific expression variation and emerging as a potential player in cancer progression. This study aimed to investigate the correlation between CALU and clinicopathological features in breast cancer (BC) and perform a functional assessment of CALU based on a microRNA-mediated knockdown approach. Methods: The BC tissues' CALU expression was measured by q-RT-PCR. We looked at correlations between changes in CALU expression and clinicopathological characteristics. We adopted a CALU knockdown approach using an artificial microRNA (amiR), expressed through an episomal vector, in BC cell lines. Epithelial to mesenchymal transition (EMT) markers were then assessed, and cell cycle, migration, proliferation, and apoptosis were analyzed. Results: When compared to the normal surrounding tissues, the BC tissues showed a 3.4-fold increase in CALU expression. This was significantly correlated with clinicopathological parameters such as histological grade, Ki-67 expression, TNM stage, lymph node involvement, and vascular lymph invasion. Key EMT markers, including GSC, MMP2, TIMP1, TGF1, SLUG, ZEB1, ZEB2, SNALI1, and TWIST1, were downregulated as a result of CALU knockdown, which prevented cell migration and proliferation and caused cell cycle arrest and apoptosis in the BC cell lines. Conclusion: The results of the amiR-mediated knockdown approach support the findings that CALU is a potential promoter of BC, as evidenced by the upregulation of CALU in BC tissues and its correlation with clinicopathological features, which highlights its role in BC progression.