Cucurbitacin E shows synergistic effect with sorafenib by inducing apoptosis in hepatocellular carcinoma cells and regulates Jak/Stat3, ERK/MAPK, PI3K/Akt/mTOR signaling pathways.

Objective: Cucurbitacin E (CuE), a natural compound found in medicinal plants such as Ecballium Elaterium, has demonstrated antiproliferative and apoptotic effects in various cancer cell types due to its tetracyclic triterpenoid structure. Sorafenib, a multi-tyrosine kinase inhibitor, is commonly used in hepatocellular carcinoma (HCC) treatment. This study aimed to investigate the anticancer effect of CuE alone and in combination with sorafenib on HepG2 cells.

Methods: CuE was extracted from Ecballium Elaterium fruit juice and quantitatively evaluated using HPLC. The effect of sorafenib and CuE on cell growth inhibition was determined using the MTT test. Cell cycle progression and apoptosis were assessed using flow cytometry. Mitochondrial damage was evaluated with ΔΨm, and DNA damage was assessed using the comet assay. The expression of Jak2/Stat3, PI3K/Akt/mTOR, MAPK, and Bcl-2 family-related genes and proteins were analyzed using western blot and qRT-PCR, respectively.

Results: Both CuE (0.1-5 µM) and sorafenib (0.5-10 µM) exhibited dose- and time-dependent antiproliferative and cytotoxic effects against the HepG2 cell line. Both compounds induced apoptosis in HepG2 cells and halted the cell cycle in the G2/M phase while causing mitochondrial and DNA damage. Both compounds down-regulated Jak2/Stat3, PI3K/Akt/mTOR, MAPK signaling pathway proteins, and Bcl-xL levels, while up-regulated Caspase-9 and Bax protein levels.

Conclusion: Based on the results of this study, it can be concluded that CuE alone or in combination with sorafenib has the potential to be an effective therapeutic option for the treatment of HCC by inducing apoptosis and regulating multiple signaling pathways.