Androgen-deprivation therapy (ADT) is the standard treatment for metastatic PCa. Although it is very effective to induce tumor regression, the majority of PCa patients receiving ADT will develop CRPC within 1-3 years. Currently, there is no effective treatment for CRPC. We investigated if rooibos exhibits anti-cancer effect on CRPC. We used LNCaP 104-R1 (R1), a human AR-rich androgen-independent PCa cells, to mimic the clinical situation of CRPC. We demonstrated that rooibos treatment suppressed the proliferation of R1 cells, as determined by MTT and Hoechst dye-based proliferation assay. Flow cytometry analysis indicated that rooibos treatment increases cell population in sub-G1 and G2/M phase but decreases in S phase. Gavage of rooibos reduced tumor growth of R1 xenografts in nude mice experiments. Micro-Western Array revealed that treatment with rooibos decreased expression of proteins including Akt, Bcl-2, but increased protein expression of cytochrome C. Conventional Western blotting suggested that rooibos treatment increased cytochrome C, LC3, and activated caspase 3 expression. In conclusion, rooibos maybe an alternative therapy for CRPC.
