Finely tuned mitogen-activated protein kinase (MAPK) signaling is important for cancer cell survival. Perturbations that push cells out of the MAPK fitness zone result in cell death. Previously, in a screen of the North China Pharmaceutical Group Corporation’s pure compound library of microbial origin, we identified elaiophylin as an autophagy inhibitor. Here, we demonstrated a new role for elaiophylin in inducing excessive endoplasmic reticulum (ER) stress, ER-derived cytoplasmic vacuolization, and consequent paraptosis by hyperactivating the MAPK pathway in multiple cancer cells. Genome-wide CRISPR/Cas9 knockout library screening identified SHP2, an upstream intermediary of the MAPK pathway, as a critical target in elaiophylin-induced paraptosis. The cellular thermal shift assay (CETSA) and surface plasmon resonance (SPR) assay further confirmed the direct binding between the SHP2 and elaiophylin. Inhibition of the SHP2/SOS1/MAPK pathway through SHP2 knockdown or pharmacological inhibitors distinctly attenuated elaiophylin-induced paraptosis and autophagy inhibition. Interestingly, elaiophylin markedly increased the already-elevated MAPK levels and preferentially killed drug-resistant cells with enhanced basal MAPK levels. Elaiophylin overcame drug resistance by triggering paraptosis in multiple tumor-bearing mouse models resistant to platinum, taxane, or PARPi, suggesting that elaiophylin might offer a reasonable therapeutic strategy for refractory ovarian cancer.

精细调节的丝裂原激活蛋白激酶 (MAPK) 信号传导对于癌细胞的存活非常重要。将细胞推出 MAPK 适应区的扰动会导致细胞死亡。此前，我们在华北制药集团公司微生物纯化合物库的筛选中，鉴定出elaophylin是一种自噬抑制剂。在这里，我们证明了 elaiophylin 在诱导过度内质网 (ER) 应激、ER 衍生的细胞质空泡化以及通过过度激活多个癌细胞中的 MAPK 通路而导致的细胞凋亡中的新作用。全基因组 CRISPR/Cas9 敲除文库筛选发现 SHP2（MAPK 途径的上游中介）是 elaiophylin 诱导的细胞凋亡的关键靶标。细胞热位移测定（CETSA）和表面等离子共振（SPR）测定进一步证实了SHP2和elaiophylin之间的直接结合。通过敲低 SHP2 或药物抑制剂抑制 SHP2/SOS1/MAPK 通路可明显减弱 elaiophylin 诱导的细胞凋亡和自噬抑制。有趣的是，elaophylin 显着增加了已经升高的 MAPK 水平，并优先杀死基础 MAPK 水平增强的耐药细胞。在对铂类、紫杉烷或 PARPi 耐药的多种荷瘤小鼠模型中，Elaiophylin 通过触发近凋亡来克服耐药性，这表明 Elaiophylin 可能为难治性卵巢癌提供合理的治疗策略。