Incaspitolide A isolated from Carpesium cernuum L. inhibits the growth of prostate cancer cells and induces apoptosis via regulation of the PI3K/Akt/xIAP pathway

Carpesium cernuum L. is a traditional medicine primarily used in Southwestern China, and it has been shown to exhibit a range of biological properties, including anti-inflammatory and antitumor activities. Incaspitolide A (IA) is a sesquiterpene isolated from C. cernuum L. The aim of the present study was to investigate the antiproliferative effects of IA on PC-3 prostate cancer cells and determine the underlying mechanism. Results from a Cell Counting Kit-8 assay demonstrated that IA significantly reduced the numbers of viable PC-3 cells in a time and dose-dependent manner. Phase-contrast microscopy revealed that the number and morphology of cells were markedly altered. Hoechst and EdU staining assays showed that IA reduced the proliferation of PC-3 cells. Flow cytometry analysis revealed that IA arrested cell cycle progression at the S phase and promoted cell apoptosis in a dose-dependent manner. Western blot analysis demonstrated that treatment with IA resulted in downregulation of phosphorylated (p-) PI3K, p-Akt, X-linked inhibitor of apoptosis (xIAP), CKD2, cyclin A2 and pro-Caspase-3 protein expression, and upregulation of cleaved poly(ADP-ribose) polymerase and P53 expression. The present results suggested that IA inhibited the growth of PC-3 cells and induced apoptosis. The underlying mechanism appeared to involve the inhibition of the PI3K/Akt/xIAP pathway. The present study indicated that IA may serve as a therapeutic for the management of prostate cancer and provided a theoretical basis for the pathogenesis of prostate cancer.