Cell suspension culture extract of Eriobotrya japonica attenuates growth and induces apoptosis in prostate cancer cells via targeting SREBP-1/FASN-driven metabolism and AR

Castration-resistant prostate cancer (CRPC) is one of the main causes of male cancer mortality. There is currently no effective treatment to cure this deadly prostate cancer (PCa) progression. However, recent research showed that activation of lipogenesis leads to CRPC progression. It provides a rationale to target the highly lipogenic activity as a novel and promising therapy against lethal CRPC.The present study aims to evaluate the anticancer efficacy and the molecular mechanism of cell suspension culture extract from Eriobotrya japonica (EJCE) in PCa, including CRPC.Cell growth, migration and invasion analyses were performed by MTT method, a wound healing assay and the transwell method, respectively. Apoptosis was assessed by a flow cytometry-based Annexin V-FITC/PI assay, caspase enzymatic activity and Western blot analyses. Lipogenesis was determined by a Fatty Acid Quantification Kit and an Oil Red O staining. The in vivo experiment was conducted by a xenograft mouse model.PCa cell growth, migration and invasion were significantly affected by EJCE. EJCE decreased expression of sterol regulatory element-binding protein-1 (SREBP-1) and fatty acid synthase (FASN) in PCa cells, two main factors for lipogenesis. By inhibiting SREBP-1/FASN, EJCE reduced the intracellular fatty acid levels and lipid droplet accumulation in PCa. Moreover, EJCE down-regulated the androgen receptor (AR) and prostate-specific antigen (PSA) in PCa cells. Significantly, EJCE exhibited the potential anticancer activity by suppressing the growth and leading to apoptosis of CRPC tumors in a xenograft mouse model.These results reveal a novel therapeutic molecular mechanism of EJCE in PCa. Blockade of SREBP-1/FASN-driven metabolism and AR by EJCE could be employed as a potent opportunity to cure malignant PCa.