Effects of the combination of brefeldin A and tunicamycin on endoplasmic reticulum stress and apoptosis in human normal hepatocytes.

Background: Due to its ability to inhibit the growth of hepatoma cells, brefeldin A (BFA) has been considered a promising drug candidate for liver cancer. However, there is limited research on its safety profile and potential impacts when administered alone or in combination with other anticancer drugs. Objective: To evaluate the safety of BFA in combination with tunicamycin (TM, a candidate anticancer drug) in human normal liver cells (HL-7702) in terms of its ability to induce endoplasmic reticulum (ER) stress and apoptosis. Methods: HL-7702 cells were exposed to BFA (0-2.5 mg/L) and TM (0-5 mg/L), either alone or in combination, for 24 h. Cell viability was measured using the CCK-8 assay, and apoptotic rates were determined using flow cytometry. The mRNA and protein levels of key factors related to cell proliferation, ER stress, and apoptosis were determined using quantitative RT-PCR and Western blot, respectively. Results: BFA and TM, either alone or in combination, significantly reduced the viability of HL-7702 cells. BFA alone and BFA + TM combination could weakly induce apoptosis, increase the expression of caspase 12, and reduce the protein level of proliferating cell nuclear antigen (PCNA). BFA alone and BFA + TM combination could significantly increase the mRNA and protein levels of binding immunoglobulin protein ( Conclusion: This study demonstrates that BFA, alone and in combination with TM, exerts mild pro-apoptotic effects on HL-7702 cells, independent of the CHOP and caspase-3 pathways. These findings underscore the necessity of evaluating the potential hepatotoxicity of BFA-based therapies, particularly in combination treatments, to ensure their safe clinical application.