5-Fluorouracil induces apoptosis in nutritional deprived hepatocellular carcinoma through mitochondrial damage

Abstract

5-Fluorouracil (5-FU) is the leading chemotherapeutic drug used to treat hepatocellular carcinoma, one of the major cancer diseases after atherosclerosis. Because of chemo-resistance, the success rate of treatment declines with time due to continuous drug exposure. Though autophagy induction is majorly responsible for acquired resistance, the exact role of this evolutionary conserved mechanism is unknown in cancer cell survival and suppression. The usual practice involves the combinatorial use of chemotherapeutic drugs with autophagy inhibitors like Chloroquine and Bafilomycin A, while neglecting the side effects caused by autophagy impairment in healthy cells. Starvation is a well-known physiological inducer of autophagy. In this study, by caloric modulation, we tried to circumvent the resistance imposed by prolonged drug exposure and investigated the effect of 5-FU in nutrient-sufficient and deficient conditions. Our findings show a substantial correlation between autophagy and increased cancer cell death in the presence of 5-FU, with negligible effects on normal cells. Experimental data revealed that nutritional deprivation augmented cell death in the presence of 5-FU through mitochondrial membrane damage and excessive reactive oxygen species (ROS) production, initiating apoptosis. Lipidation study also unveiled that under such combinatorial treatment cellular metabolism shifts from glucose to lipid biosynthesis. Overall, our experimental findings suggest that nutritional deprivation in combination with chemotherapeutic medication can be a new effective strategy to control hepatocellular carcinoma.