角蛋白19通过上调CDK1促进乳腺癌细胞增殖和化疗耐受

KRT19 enhances the proliferation and chemoresistance of breast cancer cells by upregulating CDK1

目的探讨角蛋白19（KRT19）在乳腺癌中的作用及机制。方法用qRT—PCR方法检测35例乳腺癌组织及配对癌旁组织中KRTl9表达量，分析其表达量与乳腺癌TNM分期、分化程度及远端转移等的相关性。同时检测正常乳腺上皮细胞和多种乳腺癌细胞中KRT19基础水平的表达量。在乳腺癌细胞中干预KRT19的表达，检测细胞的增殖能力和克隆形成能力，四唑氮化合物（MTS）实验检测细胞对化疗药物5-氟尿嘧啶（5-Fu）的敏感性。Western blot技术检测细胞周期相关蛋白的表达。结果KRT19在乳腺癌组织中的表达量明显高于癌旁组织，且其表达量与乳腺癌TNM分期及远端转移有关，而与乳腺癌组织分化无关。同样的，KRT19在乳腺癌细胞中的表达量也明显高于正常乳腺上皮细胞。在MCF-7细胞中过表达KRT19，能够明显增加该细胞的增殖能力、克隆形成能力及其对5-Fu的化疗耐受性。而在MDA—MB-231细胞中干扰KRT19的表达，得到完全相反的结果。机制研究中发现KRT19可上调CDK1而对p27无作用。结论KRT19在乳腺癌中明显高表达，且与乳腺癌TNM分期及远端转移等临床特征呈正相关。KRT19通过上调CDK1加强乳腺癌细胞的增殖能力和克隆形成能力以及其对5-Fu的化疗耐受性。

Objective To explore the role and mechanism of keratin 19 （KRT19） in breast cancer. Methods Quantitative real-time polymerase chain reaction （qRT-PCR） assay was used to determine KRT19 levles in 35 cases of breast cancer tissues and normal tissues. The correlation between KRT19 levels and clinical property of breast cancer was analyzed. Meanwhile, the expression levels of KRT19 in several breast cancer cells and mammary epithelial cell Michigan cancer foundation （MCF） -10A were evaluated by qRT-PCR assay. Over-expressed and knocked-down KRT19 in breast cancer cells, 3-（4,5-dimenthylthia- zol-2-yl）-5-（3-carboxymethoxyphenyl）-2-（4-sulfophenyl）-2H-tetrazolium （MTS） assay was performed to detect the proliferation and chemosensitivity of these cells. The ability of forming colon of these breast cancer cells with treated KRT19 was studied via colony-forming unit assays. Western blot assay was performed to determine expression levels of cell cycler related proteins. Results KRT19 was apregulated in breast cancer tissues comparing to normal tissues. KRT19 was positively related to tmnor node metastasis （TNM） stage and distant metastasis of breast cancer. Similarly, KRT19 was highly expressed in breast cancer cells compared to mammary epithelial cell MCF-10A. The proliferation and colony-foming ability was significantly enhanced in MCF-7 cell with overexpressed KRT19. MTS assay showed that chemosensitivity of MCF-7 cells with overexpression of KRT19 was much more remarkably reduced than the control group. However, knocking down KRT19 in breast cancer ceils MDA-MB-231 got the opposite results. Western blot assay suggested that KRT19 could obviously upregulated cyclin-dependent kinase 1 （ CDK1 ） but not p27 expression levels. Conclusions KRT19 was upregulated in breast cancer tissues and was positively related to TNM stage and distant metastasis of breast cancer. KRT19 can significantly enhance proliferation and chemoresistance of breast cancer cells via upregulating CDK1.