Multidrug resistance (MDR) in cancer remains a major challenge for the success of chemotherapy. Natural products have been a rich source for the discovery of drugs against MDR cancers. Here, we applied high-throughput cytotoxicity screening of an in-house natural product library against MDR SGC7901/VCR cells and identified that the cyclodepsipeptide verucopeptin demonstrated notable antitumor potency. Cytological profiling combined with click chemistry-based proteomics revealed that ATP6V1G directly interacted with verucopeptin. ATP6V1G, a subunit of the vacuolar H⁺-ATPase (v-ATPase) that has not been previously targeted, was essential for SGC7901/VCR cell growth. Verucopeptin exhibited strong inhibition of both v-ATPase activity and mTORC1 signaling, leading to substantial pharmacological efficacy against SGC7901/VCR cell proliferation and tumor growth in vivo. Our results demonstrate that targeting v-ATPase via its V1G subunit constitutes a unique approach for modulating v-ATPase and mTORC1 signaling with great potential for the development of therapeutics against MDR cancers.

癌症中的多药耐药性（MDR）仍然是化学疗法成功的主要挑战。天然产物已成为发现抗MDR癌症药物的丰富来源。在这里，我们应用了针对MDR SGC7901 / VCR细胞的内部天然产物库的高通量细胞毒性筛选，并确定了环二肽维库肽具有显着的抗肿瘤能力。细胞学分析与基于点击化学的蛋白质组学相结合，揭示了ATP6V1G与Verucopeptin直接相互作用。ATP6V1G，液泡H ^+的一个亚基先前尚未靶向的-ATPase（v-ATPase）对于SGC7901 / VCR细胞的生长至关重要。Verucopeptin对v-ATPase活性和mTORC1信号均表现出强烈的抑制作用，从而在体内对SGC7901 / VCR细胞增殖和肿瘤生长具有显着的药理作用。我们的研究结果表明，通过其V1G亚基靶向v-ATPase构成了一种独特的方法来调节v-ATPase和mTORC1信号，具有开发抗MDR癌症的巨大潜力。