Effect of valproic acid on expression of apoptotic markers in HeLa cell line – An <i>in vitro</i> study

Objectives: Valproic acid (VPA), a widely used antiepileptic drug, is known to have histone deacetylase inhibitory activity. It has been reported to modulate gene expression in various cancer cell lines. Alterations in the balance between proapoptotic and anti-apoptotic factors play a crucial role in cancer cell survival. This in vitro study investigated the cytotoxic effects of VPA on HeLa cells and evaluated changes in the mRNA expression of selected apoptotic regulators. Material and Methods: HeLa cell line was cultured in Dulbecco’s modified eagle medium and was treated with increasing concentrations of VPA (6.25–400 mM) for 24 h. Cell viability was assessed using the MTT assay. The half-maximal inhibitory concentration was calculated with appropriate statistical analysis. mRNA expression of proapoptotic genes (p53 and Bax) and the anti-apoptotic gene (Survivin) were analyzed using real-time polymerase chain reaction (PCR) following treatment with 12.5, 25, and 50 mM VPA. Results: VPA exposure resulted in a statistically significant reduction in HeLa cell viability in a concentration-dependent manner. Quantitative PCR analysis demonstrated a dose-dependent increase in p53 and Bax mRNA expression, along with a corresponding decrease in Survivin mRNA levels, compared with untreated controls. Conclusion: The findings indicate that VPA exerts cytotoxic effects on HeLa cells and is associated with altered expression of key apoptotic regulatory genes. While these results suggest activation of apoptotic signaling at the transcriptional level, functional evaluation of apoptosis was not performed. Therefore, the observations are mechanistic and exploratory and may provide a basis for future studies.