MTA-NPs induce preferential cytotoxicity, oxidative DNA damage, and mitochondrial apoptosis in human Hep-G2 hepatocellular carcinoma cells

Abstract

Hepatocellular carcinoma is one of the most aggressive and fatal malignancies worldwide, and the limited efficacy and severe toxic side effects of conventional chemotherapy emphasize the urgent need for safer and more effective therapeutic strategies. Nanotherapies have recently gained considerable attention due to their enhanced cellular uptake, improved bioavailability, and selective targeting of malignant cells. Although mineral trioxide aggregate nanoparticles (MTA-NPs) possess unique physicochemical and biological properties, their anticancer potential against hepatocellular carcinoma has not been fully explored. Accordingly, this study evaluated the cytotoxic activity and underlying molecular mechanisms of MTA-NPs in human hepatocellular carcinoma Hep-G2 cells, while simultaneously assessing their safety profile in normal human HFB4 melanocytes. The MTT assay results demonstrated that MTA-NPs exerted potent and selective cytotoxicity against Hep-G2 hepatocellular carcinoma cells, as demonstrated by a significant concentration-dependent decline in cancer cell viability and a markedly low IC50 value of 52.53 μg/ml. Conversely, exposure of normal HFB4 melanocytes to the same MTA-NPs concentrations resulted in only slight reductions in cell viability, primarily at the highest tested concentrations, with a substantially higher IC50 value of 239.30 μg/ml. These findings indicate the preferential anticancer activity of MTA-NPs toward Hep-G2 cells. Moreover, the calculated selectivity index of 4.55 further confirmed the selective cytotoxic potential of MTA-NPs against hepatocellular carcinoma Hep-G2 cells. Furthermore, exposure of Hep-G2 cancer cells to the IC50 concentration of MTA-NPs resulted in marked intracellular ROS overproduction, profound mitochondrial membrane depolarization, and severe genomic DNA damage, which collectively culminated in apoptotic cell death. qRT-PCR analysis further demonstrated significant downregulation of both the apoptotic p53 and mitochondrial ND3 gene expression levels, together with pronounced upregulation of the anti-apoptotic Bcl-2 gene. Collectively, these molecular alterations indicate the activation of a p53-independent mitochondria-mediated apoptotic pathway. In conclusion, MTA-NPs demonstrate potent and preferential anticancer activity against human hepatocellular carcinoma Hep-G2 cells by inducing ROS-mediated oxidative stress, genomic DNA instability, mitochondrial dysfunction, and p53-independent mitochondrial apoptosis. These findings highlight the promising therapeutic potential of MTA-NPs as a novel nanotherapeutic approach for hepatocellular carcinoma treatment. Nevertheless, additional in vitro and in vivo studies and comprehensive biosafety evaluations are still necessary prior to clinical application.