Small-molecule high-throughput screening identifies a MEK inhibitor PD1938306 that enhances sorafenib efficacy via MCL-1 and BIM in hepatocellular carcinoma cells

Comb Chem High Throughput Screen. 2022 Aug 30. doi: 10.2174/1386207325666220830145026. Online ahead of print.

Abstract

Background Sorafenib is the most widely used systematic therapy drug for treating unresectable hepatocellular carcinoma (HCC) but showed dissatisfactory efficacy in clinical applications. Objective We conducted a combinational quantitative small-molecule high-throughput screening (qHTS) to identify potential candidates to enhance the treatment effectiveness of sorafenib. Methods First, using a Hep3B human HCC cell line, 7051 approved drugs and bioactive compounds were screened, then the primary hits were tested with/ without 0.5 μM sorafenib respectively, the compound has the half maximal inhibitory concentration (IC50) shift value greater than 1.5 was thought to have the synergistic effect with sorafenib. Furthermore, the MEK inhibitor PD198306 was selected for further mechanistic study. Results 12 effective compounds were identified, including kinase inhibitors that target MEK, AURKB, CAMK, ROCK2, BRAF, PI3K, AKT and EGFR, as well as a μ-opioid receptor agonist and a L-type calcium channel blocker. The mechanistic research of the combination of sorafenib plus PD198306 showed that the two compounds synergistically inhibited MEK-ERK and mTORC1-4EBP1, and induced apoptosis in HCC cells, which can be attributed to the transcriptional and posttranslational regulation of MCL-1 and BIM. Conclusion Small-molecule qHTS identifies MEK inhibitor PD1938306 as a potent sorafenib enhancer, together with several novel combination strategies that are valuable for further studies.

Keywords: MEK inhibitor; hepatocellular carcinoma; small-molecule high-throughput screening; sorafenib.