Identification of a Novel ERK5 (MAPK7) Inhibitor, MHJ-627, and Verification of Its Potent Anticancer Efficacy in Cervical Cancer HeLa Cells

Extracellular signal-regulated kinase 5 (ERK5), a member of the mitogen-activated protein kinase (MAPK) family, is involved in key cellular processes. However, overexpression and upregulation of ERK5 have been reported in various cancers, and ERK5 is associated with almost every biological characteristic of cancer cells. Accordingly, ERK5 has become a novel target for the development of anticancer drugs as inhibition of ERK5 shows suppressive effects of the deleterious properties of cancer cells. Herein, we report the synthesis and identification of a novel ERK5 inhibitor, MHJ-627, and verify its potent anticancer efficacy in a yeast model and the cervical cancer HeLa cell line. MHJ-627 successfully inhibited the kinase activity of ERK5 (IC₅₀: 0.91 μM) and promoted the mRNA expression of tumor suppressors and anti-metastatic genes. Moreover, we observed significant cancer cell death, accompanied by a reduction in mRNA levels of the cell proliferation marker, proliferating cell nuclear antigen (PCNA), following ERK5 inhibition due to MHJ-627 treatment. We expect this finding to serve as a lead compound for further identification of inhibitors for ERK5-directed novel approaches for oncotherapy with increased specificity.