人乳腺癌ZR-75-1细胞中RNA结合蛋白38对孕激素受体表达的调节作用及其机制

Regulatory effect and mechanism of RNA binding motif protein 38 on the expression of progesterone receptor in human breast cancer ZR-75-1 cells

目的明确乳腺癌细胞株ZR-75—1中RNA结合蛋白38（RNPCI）的表达对孕激素受体（PR）表达的调节作用。方法采用慢病毒转染法过表达RNPCI基因，以实时荧光定量PCR（qRT—PCR）和Westernblot法检测RNPCI调节PR表达的情况；以放线菌素实验研究RNPCI调控PR表达的机制。采用免疫组化法检测80例乳腺癌组织中RNPCI蛋白和PR蛋白的表达。结果免疫组化检测结果显示，在PR蛋白表达阳性的29例乳腺癌组织中，RNPCI蛋白高表达16例；在PR蛋白表达阴性的51例乳腺癌组织中，RNPCI蛋白低表达41例。qRT—PCR检测结果显示，过表达RNPCI组和过表达对照组乳腺癌ZR-75-1细胞中，PRmRNA的相对表达量分别为1．764±0．028和1．001±0．037．差异有统计学意义（P〈0．01）；而干扰RNPCI组和干扰对照组乳腺癌ZR-75-1细胞中PRmRNA的相对表达量分别为0．579±0．007和1．000±0．002，差异有统计学意义（P〈0．01）。Westernblot法检测结果显示，在乳腺癌ZR-75—1细胞中，过表达RNPCI可使PR蛋白的表达增加；而敲除RNPCI的表达后，PR蛋白的表达减少。放线菌素实验结果显示，乳腺癌ZR-75—1细胞过表达RNCPl后，PRmRNA的稳定性增加，其半衰期由过表达对照组的4．0h增加为6．5h；而敲除RNPCI的表达后，PRmRNA的稳定性降低，其半衰期由干扰对照组的4．1h降为3．0h。结论RNPCI在调节乳腺癌ZR-75-1细胞PRmRNA和蛋白的表达中发挥重要作用。

Objective To investigate the regulatory mechanism of RNA binding motif protein 38 （RNPC1） on the expression of progesterone receptor （PR） in breast cancer cell line ZR-75-1. Methods Lentiviral vector was used to induce overexpression of RNPC1 in ZR-75-1 cells, qRT-PCR and Western blot were used to assess the regulatory effect of RNPC1 on PR expression. Actinomycin was used to detect the regulatory mechanism involved. Immunohistochemieal （IHC） staining was used to determine the protein expression of RNPC1 and PR in 80 breast cancer tissues. Results IHC staining showed that the expression of RNPC1 was significantly higher in the PR positive breast cancer tissues than that in the PR negative breast cancer tissues （P〈0.05）. The qRT-PCR results showed that overexpression of RNPC 1 in ZR-75-1 cells significantly upregulated the mRNA level of PR （ 1.764＋0.028 vs. 1.001 ~0.037, P〈0.01 ）, whereas knockdown of RNPC1 did the opposite （0.579~ 0.007 vs. 1.000~0.002, P〈0.01）.The Western blot resuhs also showed that overexpression of RNPC1 up-regulated PR levels, while knockdown of RNPC1 resulted in down- regulation of PR levels in the ZR-75-1 cells.The actinomycin assay showed that overexpression of RNPC1 increased the mRNA stability of PR. The half-life of PR mRNA was increased from 4.0 h to 6.5 h. Knockdown of RNPC1 decreased the mRNA stability of PR and the half-life of PR transcript was decreased from 4.1 h to 3.0 h. Conclusion RNPC1 plays a crucial role in regulating the expression of PR in breast cancer ZR-75-1 cells.