Selenium Nanoparticles Show Anticancer Activity Through Regulation of HIF-1α and HIF-2α Under Hypoxic Condition in Liver Cancer Cells

Tumor microenvironment has significant influence in therapeutic response and clinical outcome. Combination therapy is more effective in cancer treatment compared with monotherapy. Any chemical or drug that targets tumor microenvironment pathway, will be a boon to combination cancer chemotherapy. Combination therapy through micronutrient may have added advantage in clinical applications. Selenium (Se) is an essential micronutrient; Se in the form of Se nanoparticles (SeNPs) show efficient anticancer properties and may have the potential to target tumor niche such as hypoxic environment. The aim of this study was to find out the anticancer effect of SeNPs on cell line HepG2 under hypoxic condition and also to evaluate their effect on the translocation of hypoxia-inducible factors (HIFs) from cytoplasm to nucleus that help the cells to survive under hypoxic condition. It was found that the SeNPs induce HepG2 cell death in normoxic and hypoxic conditions, however, hypoxic condition showed higher LD50. SeNP concentration is directly proportional to cell death in both the conditions. Furthermore, intracellular accumulation of Se is not affected by hypoxia. SeNP-induced HepG2 cell death is due to increased DNA damage, nuclear condensation, and mitochondrial membrane potential disturbance. Furthermore, SeNPs were also found to decrease the translocation of HIFs from cytosol to the nucleus. After analyzing the results, it is concluded that SeNP treatment disturbs tumor niche through the inhibition of HIFs' translocation from cytosol to nucleus. SeNPs in synergy with primary drug, such as doxorubicin (DOX), may enhance the anticancer efficacy of DOX through regulation of HIFs, warranting further research.