Anticancer and apoptotic effects of orange peel extract and naringin on doxorubicin-induced apoptosis in human esophageal squamous carcinoma cell line

Abstract

The presence of bioactive compounds in orange peel, which possess strong antioxidant properties, suggests that they may have pharmacological effects on cancer cells while maintaining low toxicity. This study sought to investigate the anticancer and apoptotic effects of orange peel extract (OPE) and its main flavonoid derivative, naringin (NR), on doxorubicin (Dox)-induced apoptosis in a human esophageal squamous carcinoma cell line (ESCC). The assessment of cytotoxicity and DNA fragmentation was conducted by employing the methylthiazoletetrazolium (MTT) assay and the fluorescent nuclear dye 4’,6-diamidino-2-phenylindole (DAPI) assay, respectively. The levels of Bax, Bcl-2, p21, p53, and caspases 8 and 9 were quantified through the utilization of ELISA to determine the protein expression. A decline in the viability of YM-1 cells treated with OPE, NR, and Dox was observed in a dose-dependent manner. The combination of Dox with OPE and NR demonstrated a protective effect against Dox-induced cytotoxicity. Furthermore, normal cells exposed to Dox exhibited the lowest viability compared to other treatments, while the combination of Dox with OPE or NR reduced its cytotoxic effects. The interaction between Dox and OPE as well as NR resulted in a decrease in apoptotic bodies. The YM-1 cells subjected to treatments showed an up-regulation of the pro-apoptotic Bax gene. However, the interaction between Dox and OPE as well as NR led to the down-regulation of Bax. Furthermore, the activation of executioner caspases 8 and 9 was found in the YM-1 cell line exposed to Dox and its combination with OPE and NR. The YM-1 cells subjected to the treatments exhibited an overexpression of the anti-tumor genes p21 and p53. Conversely, the interaction between Dox and OPE as well as NR resulted in the down-regulation of the anti-tumor genes P21 and P53. In conclusion, this study suggests that OPE and NR have the potential to induce apoptosis in ESCC through Bax-dependent pathways and could serve as promising agents to mitigate the toxic effects of Dox on ESCC.