Androgen-like effects of Cordyceps sinensis and its impact on the radiosensitivity of VCaP prostate cancer cells

Objective: To investigate the androgen-like effects of Cordyceps sinensis (CS) and its impact on the radiosensitivity of VCaP prostate cancer cells. Methods: The hormone levels and weight index of reproductive organs in mice were determined after gavage with CS. Clonogenic assay was performed to determine the impact of CS on the radiosensitivity of VCaP cells. The 3-(4, 5-dimethylthiazol-2-yl)-5(3-carboxymethonyphenol)-2-(4-sulfophenyl)-2H-tetrazolium assay, flow cytometry, and tumor xenografts in nude mice were performed to determine the effects of CS on the proliferation of VCaP cells (androgen receptor-positive) and PC-3 cells (androgen receptor-negative) in vitro and in vivo. Serum prostate-specific antigen (PSA) levels in nude mice were evaluated. Data were analyzed by one-way analysis of variance or t-test. Results: The testosterone level and weight of prostate in mice were significantly higher in the CS group than in the control group ((8.28 ± 1.94) vs. (2.08 ± 1.24) ng/ml, P = 0.023; (0.53 ± 0.04) vs. (0.31 ± 0.04) mg/g, P = 0.006). The radiosensitivity enhancement ratio (ratio of D₀ values) was 0.80. The viability of VCaP cells was significantly higher in the CS group than in the control group (1.32 ± 0.07 vs. 0.66 ± 0.02, P = 0.000), and colony forming efficiency was significantly enhanced in the CS group than in the control group (57.0% ± 1.9% vs. 47.0% ± 0.6%, P = 0.005). VCaP tumor xenografts in nude mice were inclined to grow faster in the CS group than in the control group, and the serum PSA level in the CS group was significantly higher than that in the control group ((0.66 ± 0.04) vs. (0.26 ± 0.06) ng/ml, P = 0.000). However, CS had no effect on PC-3 cells at the working concentration. Conclusions: CS has the androgen-like effects. It may also promote the proliferation and reduce the radiosensitivity of androgen receptor-positive VCaP cells. (authors)