DNA repair pathways-targeted cyclovirobuxine inhibits castration-resistant prostate cancer growth by promoting cell apoptosis and cycle arrest.

ABSTRACT

BACKGROUND: Castration-resistant prostate cancer (CRPC) is a deadly malignancy without effective therapeutics. Cyclovirobuxine (CVB) can play an anticancer role by inhibiting mitochondrial function, regulating tumor cell apoptosis, dysregulating autophagy, and other mechanisms. This study aimed to examine the function and mechanism of CVB in CRPC to provide new insights into CRPC treatment. METHODS: The effect of CVB on PC3 and C4-2 cell viability was determined using a CCK8 assay. Core therapeutic targets of CVB in CRPC cells were identified using RNA sequencing, online database, and PPI network analyses. Western blotting, RT-qPCR and molecular docking were performed to evaluate the regulation of core targets by CVB. Utilizing GO and KEGG enrichment analyses, the probable anti-CRPC mechanism of CVB was investigated. Immunofluorescence, flow cytometry and colony formation assays were used to verify the potential phenotypic regulatory role of CVB in CRPC. RESULTS: CVB inhibited CRPC cell activity in a concentration-dependent manner. Mechanistically, it primarily regulated BRCA1-, POLD1-, BLM-, MSH2-, MSH6- and PCNA-mediated mismatch repair, homologous recombination repair, base excision repair, Fanconi anemia repair, and nucleotide excision repair pathways. Immunofluorescence, Western blot, flow cytometry and colony formation experiments showed that CVB induced DNA damage accumulation, cell apoptosis, and cell cycle arrest and inhibited CRPC cell proliferation. CONCLUSION: CVB can induce DNA damage accumulation in CRPC cells by targeting DNA repair pathways and then induce cell apoptosis and cell cycle arrest, eventually leading to inhibition of the long-term proliferation of CRPC cells.