Aberrant MEK5 signalling promotes clear cell renal cell carcinoma development via mTOR activation

Purpose: This study was designed to evaluate the role and expression of MEK5 signalling in clear cell renal cell carcinoma (ccRCC) and to determine the relevance of MEK5 and mTOR signalling in ccRCC.

Methods: The expression of MEK5 was compared between ccRCC and normal tissues using the ONCOMINE and TCGA databases. MEK5 expression was evaluated in 14 human ccRCC samples. CCK8, wound-healing, and clone formation assays were performed to examine the cell proliferation, migration, and clone formation abilities of ccRCC cells treated with MEK5 and the inhibitor BIX02189. Furthermore, Western blotting was performed to verify the regulation and influence of MEK5 on the mTOR signalling pathway. Finally, a murine subcutaneous tumour model was constructed, and the effect and safety of BIX02189 were evaluated in vivo.

Results: The ONCOMINE and TCGA databases indicated that MEK5 expression in ccRCC was significantly higher than that in normal tissues, which was further confirmed in clinical specimens. MEK5 knockdown markedly inhibited ccRCC cell proliferation, colony formation, and migration, whereas MEK5 overexpression resulted in the opposite results. Western blotting revealed that overexpression of MEK5 could further activate the mTOR signalling pathway. Moreover, the MEK5 inhibitor BIX02189 significantly inhibited cell proliferation, arrested the cell cycle in the G0/G1 phase, induced apoptosis, and effectively inhibited cell migration and clone formation. BIX02189 also showed an excellent antitumor effect and a favourable safety profile in murine models.

Conclusions: MEK5 expression was aberrantly increased in ccRCC, which activated the mTOR signalling pathway and regulated cell proliferation, cell cycle progression, migration, and clone formation in ccRCC. Targeted inhibition of MEK5 represents a promising new strategy in patients with ccRCC.

Comments：

The study found that MEK5 expression is higher in clear cell renal cell carcinoma (ccRCC) than in normal tissues, and that targeting MEK5 with the inhibitor BIX02189 significantly inhibited ccRCC cell proliferation, migration, and colony formation in vitro and in vivo, and had an excellent safety profile.

Related Products

Cat.No.	Product Name	Information
S1531	BIX 02189	BIX02189 is a selective inhibitor of MEK5 with IC50 of 1.5 nM, also inhibits ERK5 catalytic activity with IC50 of 59 nM in cell-free assays, and does not inhibit closely related kinases MEK1, MEK2, ERK2, and JNK2.

Related Targets

ERK MEK