c-kit inhibitor masitinib induces reactive oxygen species-dependent apoptosis in c-kit-negative HepG2 cells

Eur J Pharmacol. 2022 Sep 15;931:175183. doi: 10.1016/j.ejphar.2022.175183. Epub 2022 Aug 5.


Tumor-specific growth signal inhibition is a major anticancer strategy. Receptor tyrosine kinases (RTKs) are the most upstream receptors for growth signaling in cancer. Therefore, inhibition of RTKs has been proposed as an efficient therapeutic target. Masitinib, a c-kit inhibitor of the c-kit RTK, was developed to treat mastocytoma in dogs. In humans, however, the antitumor efficacy of masitinib was found to be attenuated against tumor cells with mutations of the c-kit gene. Here, we report that masitinib induced cell death via the intrinsic apoptotic pathway in HepG2, a c-kit-negative hepatocellular carcinoma cell line. In masitinib-treated HepG2 cells, increases in intracellular reactive oxygen species levels, loss of mitochondrial membrane potential, and cleavage of caspase-9 were observed, activating the intrinsic apoptotic pathway. Moreover, the cytotoxicity of masitinib to HepG2 cells was suppressed by treatment with the antioxidant N-acetyl-L-cysteine or a c-Jun N-terminal kinase/stress-activated protein kinase (JNKs) inhibitor. Thus, we demonstrated that the anticancer effects of masitinib are not due to its targeting c-kit, but rather to its targeting the redox balance via the JNK pathway in HepG2 cells. These results suggest that masitinib has the potential to provide a robust antitumor effect in tumor lesions and could also be applied to a broad range of other anticancer therapies.

Keywords: Masitinib; Mitochondrial apoptosis; Reactive oxygen species (ROS); Receptor tyrosine kinase; c-Jun N-Terminal kinases (JNKs).

MeSH terms

  • Animals
  • Apoptosis*
  • Benzamides
  • Cell Line, Tumor
  • Dogs
  • Hep G2 Cells
  • Humans
  • JNK Mitogen-Activated Protein Kinases / metabolism
  • Piperidines
  • Proto-Oncogene Proteins c-kit / antagonists & inhibitors*
  • Proto-Oncogene Proteins c-kit / metabolism
  • Pyridines* / metabolism
  • Pyridines* / pharmacology
  • Reactive Oxygen Species / metabolism
  • Thiazoles


  • Benzamides
  • Piperidines
  • Pyridines
  • Reactive Oxygen Species
  • Thiazoles
  • KIT protein, human
  • Proto-Oncogene Proteins c-kit
  • JNK Mitogen-Activated Protein Kinases
  • masitinib