Pictilisib and nutrient stress synergize to induce methuosis via PI(4,5)P2-dependent macropinocytic dysregulation in cancer cells. (PubMed, Cell Death Dis)
Active macropinocytic uptake is essential for methuosis, as demonstrated by suppression with EIPA and Bafilomycin A1, whereas the AKT inhibitor MK2206 has no effect, establishing that direct PI3K inhibition, rather than AKT signaling, is required. In xenograft models, dietary restriction synergizes with Pictilisib to suppress tumor growth, correlating with pronounced intratumoral vacuolization. These findings reveal that combining PI3K inhibition with nutrient restriction converts cytostatic responses into methuosis-driven cytotoxicity via PI(4,5)P2-dependent macropinocytic dysregulation, providing a rational pharmacologic-dietary strategy to enhance PI3K-targeted cancer efficacy.