Anticancer saponin OSW-1 is a novel class of selective Golgi stress inducer.

OSW-1 is a plant-derived natural product proposed to selectively kill cancer cells by binding to members of the oxysterol binding protein family, thereby disrupting lipid/sterol homeostasis. However, how these protein-ligand interactions mediate cell death signaling has remained elusive. Here, we discovered that OSW-1 selectively activates the Golgi stress response leading to apoptosis, providing a mechanistic basis for the anticancer activity of OSW-1.

Kuwanon H Inhibits Melanoma Growth through Cytotoxic Endoplasmic Reticulum Stress and Impaired Autophagy Flux.

Although great progress has been made recently in targeted and immune-based therapies, additional treatments are needed for most melanoma patients due to acquired chemoresistance, recurrence, or metastasis. Elevated autophagy is required for the pathogenesis of melanoma to attenuate metabolic stress, protecting cancer cells from chemotherapeutics or radiation. Thus, intervention with autophagy is a promising strategy for melanoma treatment. Here, we examined a novel antimelanoma natural compound named kuwanon H (KuH), which significantly inhibited melanoma cell growth in vitro/vivo. Mechanistically, KuH induced cytotoxic endoplasmic reticulum (ER) stress, which inhibited cell viability and induced apoptosis. Meanwhile, KuH-induced ER stress mediated autophagysome formation through the ATF4-DDIT3-TRIB3-AKT-MTOR axis. Importantly, KuH impaired autophagy flux, which contributed to the anticancer effects of KuH. Finally, our results showed that KuH enhanced the sensitivity of melanoma cells to cisplatin, both in vitro and in vivo, by impairing autophagy degradation of reactive oxygen species and damaged mitochondria. Our findings indicate that KuH is a promising candidate anticancer natural product for melanoma therapy.