MELK expression in ovarian cancer correlates with poor outcome and its inhibition by OTSSP167 abrogates proliferation and viability of ovarian cancer cells

MELK inhibition by OTSSP167 may thus present a strategy to treat patients with aggressive, progressive, and recurrent ovarian cancer.

Maternal embryonic leucine-zipper kinase (MELK) shows oncogenic properties in basal-like breast cancer, a cancer subtype sharing common molecular features with high-grade serous ovarian cancer. We examined the potential of MELK as a molecular and pharmacological target for treatment of epithelial ovarian cancer (EOC).

Elevated MELK expression was correlated with histological grading (n=6 data sets, p<0.05) and progression-free survival (HR 5.73, p<0.01) in OC patients and elevated MELK expression in other cancers with disease-free survival (n=3495, HR 1.071, p<0.001). Inhibition or depletion of MELK reduced cell proliferation and anchorage-dependent and -independent growth in various OC cell lines through a G2/M cell cycle arrest, eventually resulting in apoptosis. OTSSP167 retained its cytotoxicity in Cisplatin- and Paclitaxel-resistant IGROV1 and TYK-nu OC cells and sensitized OVCAR8 cells to Carboplatin but not Paclitaxel.