Insights into histone deacetylase inhibitors-induced cell death in cancer cell lines

Histone deacetylase inhibitors (HDACis) induce cell death in many chemoresistant cancer models, suggesting their potential as alternative treatments for these malignancies. However, their efficacy in solid tumors remains limited. Therefore, understanding the molecular mechanisms underlying HDACi-induced cell death is essential for developing targeted activators of these pathways, enabling the selective elimination of chemoresistant cancer cells while minimizing the widespread transcriptional effects of HDACis. In this study, we investigated HDACi-induced cell death across models of different cellular origins to determine whether a universal molecular mechanism triggers this process. Our findings demonstrate that HDACi-induced cell death is TP53-independent, resistant to caspase inhibitors, and sensitive to serine protease inhibitors. This form of cell death requires intracellular calcium mobilization to induce mitochondrial depolarization. Using DNA arrays, apoptosis protein arrays, and ELISA assays, combined with siRNA-mediated gene silencing, we identified genes with a causal relationship to TSA-induced cell death. These include dual-specificity phosphatases such as DUSP3 and DUSP10; endoplasmic reticulum stress-related genes such as XBP1, MBTPS1, MBTPS2, and RPS6KA5; and other genes like BAX, AIF, EAF2, NANOS1, and CCNYL1. Our findings reveal novel potential targets for developing antineoplastic agents designed to exploit HDACi-induced cell death pathways, providing a strategy to overcome chemoresistance in cancer therapy.