Induction of ROS-mediated genomic instability, mitochondrial deploarization and p53-independent mitochondrial apoptotic cell death by bioactive glass nanoparticles in human A431 epidermoid skin cancer cells

Abstract

Epidermoid skin cancer remains a significant clinical challenge due to the limited selectivity, systemic toxicity, and resistance associated with conventional chemotherapies. Bioactive glass nanoparticles (BGNPs), widely recognized for their regenerative capacity and excellent biocompatibility, have recently gained attention in nanomedicine. However, their anticancer potential, particularly in epidermoid skin cancer, has not yet been investigated. Therefore, the present study was conducted to systematically evaluate, for the first time, the cytotoxic effects and underlying molecular mechanisms of BGNPs in human A431 epidermoid carcinoma cells.

Cancerous A431cells were treated with BGNPs across a concentration range of 7.8–1000 µg/ml, and cytotoxicity was quantified using the MTT assay, revealing a potent concentration-dependent reduction in cell viability with an IC50 value of 187.81 µg/ml. Mechanistic analyses demonstrated that A431 cell exposure to BGNPs at the IC50 concentration led to a significant increase in intracellular reactive oxygen species (ROS), as detected using the 2′,7′-dichlorodihydrofluorescein diacetate (DCFH-DA) assay, accompanied by severe mitochondrial membrane depolarization and dramatic genomic DNA damage, as confirmed by Rhodamine-123 staining and alkaline comet assay. Apoptosis was validated by DAPI staining and chromatin diffusion assays, which demonstrated characteristic nuclear condensation and fragmentation, along with significant increases in the proportion of apoptotic A431 cells following BGNPs treatment compared to untreated control cells. Furthermore, qRT-PCR analysis showed significant downregulation of apoptotic p53 alongside marked upregulation of anti-apoptotic Bcl-2 and mitochondrial ND3 genes, indicating disruption of mitochondrial and apoptotic regulatory pathways. Conclusion: Collectively, this study provides novel mechanistic evidence that BGNPs induce potent cytotoxicity in A431 cells through a ROS-mediated, mitochondria-dependent apoptotic pathway. Despite being limited to a single in vitro cell line, these findings highlight BGNPs as promising multifunctional anticancer candidates, warranting further in vitro studies across additional skin cancer models and normal keratinocyte cell lines alongside n vivo validation and exploration in combination therapeutic strategies.