Discovery of Potent and Selective Phosphatidylinositol 3-Phosphate 5-Kinase (PIKfyve) Inhibitors as Methuosis Inducers

Abstract

Cytoplasmic vacuolation-associated cell death, known as methuosis, offers a promising nonapoptotic approach for cancer treatment. In this study, we outline the synthesis and evaluation of potent methuosis-inducing compounds. These compounds selectively induce cell death, characterized by extensive cytoplasmic vacuolation in HeLa and MDA-MB-231 cells. Notably, compound <b>L22</b> exhibited a remarkable interaction with PIKfyve kinase, boasting a <i>K</i>_d value of 0.47 nM, surpassing the positive controls D-13 and MOMIPP in potency. Furthermore, it is important to highlight that cell death induced by compound <b>L22</b> is unequivocally attributed to methuosis as it differs from apoptosis, necrosis, or autophagy. Importantly, when administered orally, <b>L22</b> effectively inhibited tumor growth in a HeLa xenograft model without any apparent signs of toxicity. These results underscore the potential of <b>L22</b> as a valuable tool for in-depth investigations into the mechanisms of methuosis and as a promising lead compound to guide structural optimization.