Epigenetic modulation of Aurora kinases A and B by 5-aza-2'-deoxycytidine in breast cancer cells

Abstract

Introduction: Aurora kinases A (AURKA) and B (AURKB) play crucial roles in cell cycle regulation and are frequently overexpressed in various types of cancer, including breast cancer. Epigenetic alterations, such as deoxyribonucleic acid (DNA)
methylation, may contribute to the dysregulation of these genes. Objective: This study aimed to evaluate the modulatory
effects of 5-aza-2′-deoxycytidine (5-aza-dC), a DNA methylation inhibitor, on the expression of AURKA and AURKB genes
in luminal (MCF7) and human epidermal growth factor receptor-type 2-positive (HER2+) (BT474) breast cancer cell lines
treated with different concentrations of the demethylating agent. Methods: Cells were cultured under standard conditions (37°C, 5% CO₂) and treated with 5-aza-dC at various concentrations (10, 20, 30, and 50 μM) for 24, 48, and 72 hours.
After treatment, total ribonucleic acid (RNA) was extracted and converted into complementary (c)DNA, followed by gene
expression analysis via reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Normalization was performed using housekeeping genes, and data were statistically evaluated using analysis of variance (ANOVA), with Tukey’s
post hoc test, and with p<0.05 considered significant. Results: The experiments revealed a dose-dependent response profile
in both cell lines. In MCF7, a significant reduction in AURKA expression was observed at 30 μM and 50 μM, mainly after
48 hours and 72 hours (p<0.01). For AURKB, a significant reduction was observed starting at 20 μM at 72 hours (p<0.05).
In the BT474 cell line, both AURKA and AURKB showed a significant decrease in expression at 50 μM, especially at 72 hours
(p<0.001). Conclusion: Treatment with 5-aza-dC negatively modulated AURKA and AURKB expression in a dose- and
time-dependent manner, indicating a possible antitumor epigenetic effect. These findings suggest the potential of 5-azadC as an adjuvant therapeutic agent in breast cancers characterized by Aurora kinase overexpression.