[Oxalis inhibits prostate tumor in the mouse model of castration-resistant prostate cancer: Effect and mechanism].

OBJECTIVE: To investigate the inhibitory effect of oxalis on prostate tumor in the mouse model of castration-resistant prostate cancer (CRPC) and its action mechanism. METHODS: We established a CRPC model in 40 male C57/BL mice aged 6－8 weeks, divided them randomly into four groups of an equal number, and treated them intragastrically with normal saline (control), low-dose oxalis (5 mg/kg/d), medium-dose oxalis (10 mg/kg/d), and high-dose oxalis (15 mg/kg/d), respectively. After 28 days of treatment, we measured the tumor volume and body weight of the mice in different groups, calculated the tumor-inhibition rate, examined the histomorphological changes of the prostate tumors by HE staining, and detected the expressions of the nuclear factor-κB (NF-κB) signaling pathway and its downstream proteins in the tumor tissue by immunofluorescence assay. RESULTS: In comparison with the controls, the mice in the low-, medium- and high-dose oxalis groups showed a gradual decrease in tumor cell concentration and cell degeneration, and a gradually increased number of necrotic tumor cells. The volume and mean weight of prostate tumors were significantly reduced (P < 0.05), the expressions of NF-κB p65 and Ki67 proteins remarkably down-regulated (P < 0.05), and that of the Bax protein markedly up-regulated (P < 0.05) in the oxalis groups compared with the controls. CONCLUSION: Oxalis can inhibit the growth of prostate tumor in CRPC mice possibly by down-regulating the NF-κB signaling pathway and the expressions of p65 and Ki67 and up-regulating the expression of Bax, and thereby promoting the degeneration and necrosis of tumor cells.