HRAS-driven cancer cells are vulnerable to TRPML1 inhibition.

By serving as intermediaries between cellular metabolism and the bioenergetic demands of proliferation, endolysosomes allow cancer cells to thrive under normally detrimental conditions. Here, we show that an endolysosomal TRP channel, TRPML1, is necessary for the proliferation of cancer cells that bear activating mutations in Expression of , which encodes TRPML1, is significantly elevated in -positive tumors and inversely correlated with patient prognosis. Concordantly, knockdown or TRPML1 inhibition selectively reduces the proliferation of cancer cells that express oncogenic, but not wild-type, Mechanistically, TRPML1 maintains oncogenic HRAS in signaling-competent nanoclusters at the plasma membrane by mediating cholesterol de-esterification and transport. TRPML1 inhibition disrupts the distribution and levels of cholesterol and thereby attenuates HRAS nanoclustering and plasma membrane abundance, ERK phosphorylation, and cell proliferation. These findings reveal a selective vulnerability of -driven cancers to TRPML1 inhibition, which may be leveraged as an actionable therapeutic strategy.