前列腺癌细胞中核因子κB家族成员调控乳腺丝氨酸蛋白酶抑制剂表达的机制

NF-κB subunits regulate maspin expression in prostate cancer cells in vitro

目的探讨核因子κB（NF—κB）家族成员（RelA、pSO、RelB和p52）调控抑癌基因乳腺丝氨酸蛋白酶抑制剂（Maspin）表达的可能机制。方法采用Westernblot法检测前列腺癌细胞株DUl45、PC-3和LNCaP中NF-κB家族成员和Maspin蛋白的表达情况。采用RNA干扰技术结合Westernblot法，检测RelB或RelA沉默对前列腺癌DUl45细胞中Maspin蛋白表达的影响。采用流式细胞术检测RelB沉默后前列腺癌DUl45细胞的死亡情况。通过转染RelB表达质粒并建立稳定表达细胞株，观察过表达RelB对前列腺癌PC-3细胞中Maspin蛋白表达的影响。结果RelA、pSO、RelB和p52蛋白在雄激素非依赖型前列腺癌细胞株DUl45和PC-3中呈持续性高表达，其中RelB蛋白在DUl45细胞中的表达最为显著。Maspin蛋白在LNCaP和DUl45细胞中低表达，而在PC-3细胞中高表达。在DUl45细胞中，沉默RelB可以诱导Maspin蛋白表达上调，同时促进细胞死亡[死亡率为（13．3±4．2）％]。在PC．3细胞中，过表达RelB可抑制Maspin的内源性表达。RelA沉默对DUl45细胞中Maspin蛋白的表达无显著影响。结论在雄激素非依赖型前列腺癌细胞株中，NF-κB经典与非经典通路蛋白持续性活化，RelB与Maspin的表达呈负相关性。RelB负性调控了内源性Maspin的表达，进而影响了前列腺癌细胞的存活。RelA并不参与对Maspin表达的调控。

Objective To explore how NF-κB family members regulate maspin expression in prostate cancer cells. Methods The expression of NF-κB subunits and maspin was detected by Western blot analysis in prostate cancer DU145, PC-3, and LNCaP cell lines. RNA interference was performed to analyze whether RelB- or RelA-deletion affectes cell death as well as the expression of NF-κB subunits and maspin. The impact of RelB-silencing in DU145 cells was investigated by flow cytometry. The regulation of RelB on maspin expression in the prostate cancer PC-3 cells was also examined via stable transfection of RelB expression plasmid. Results RelA, p50, RelB, and p52 were constitutively expressed in androgen- independent prostate cancer DU145 and PC-3 cells, while RelB had the highest expression in DU145 cells. Low expression of maspin was detected in LNCaP and DU145 cells, but elevated expression in PC-3 cells. RelB-silencing in DU145 cells by siRNA interference upregulated the endogenous expression of maspin and induced cell apoptosis （ 13.3±4.2） %. Overexpression of RelB in PC-3 cells inhibited the endogenous expression of maspin. RelA-silecing had no significant influence on the endogenous expression of maspin. Conclusions The classical and alternative NF-κB activitions are sustained in androgen-independent prostate cancer cell lines. The expressions of RelB and maspin are inversely correlated in these cancer cells. The expression of RelB negatively regulates the endogenous expression of maspin, then interferes the cell survival. RelA is not involved in the regulation of maspin expression.