Effect of castration on miR-301a expression in a mouse xenograft model of human prostate cancer / 中华泌尿外科杂志

ABSTRACT

Objective To investigate the changes of miR-301a and its host gene expression SKA2 in LNCaP prostate cancer xenografts in the castrated nude mice.Methods LNCaP cells were inoculated subcutaneously in nude mice to establish xenograft models of human prostate cancer.When the tumor volume grew to 200 mm3,the nude mice were randomly divided into the following 4 groups(n =6) 2 groups of nude mice to surgical castration,the other 2 groups of mice as control groups.The growth of those xnografts in nude mice was observed weekly and a growth curve of the xenografts was drawn.A point time during the process of tumor-regressing was selected when a group of castrated nude mice and a group of control mice were killed(the first time).The other 2 groups nude mice were continued to be observed.Another point time in the process of tumor re-growth,the rest castrated nude mice and control mice were killed(the second time).The tumors were weighted and the inhibitory rate was calculated.MiR-301a and SKA2 expression were detected by real-time PCR.Results The growth of the xenografts gradually decreased in LNCaP xenografts in nude mice after castration.After 13 days,the xenografls sizes decreased to(62.5 ±21.5)mm3 and tumor inhibitory rate was 59.8％(t =-3.895,P =0.018)in castration group of nude mice.At the 17th day after castration,tumor volume reached the minimum,and then gradually increased.At the 41st day after castration,tumor volumes in castration group increased to(364.5 ±97.3)mm3 and the tumor inhibitory rate was 62.2％(t =-7.017,P =0.002).MiR-301a and SKA2 in the first time of xenografts from the castrated group were both significantly lower than those of the control group(0.65-fold and 0.50-fold,respectively).However,their expressions in the second time of xenografts from the castrated group increased and were consistent with the control group(P ＞ 0.05).Conclusions Castration could turn prostate cancer xenografts from androgen-dependent into androgen-independent.There could be a close correlation between the characteristic of prostate cancer androgen-dependent and the expressions of miR-301 a and host gene SKA2.