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 ceils,3-(4,5-dimenthylthiazol-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 ceil cycler related proteins.Results KRT19 was upregulated in breast cancer tissues comparing to normal tissues.KRT19 was positively related to tumor 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-forming ability was significantly enhanced in MCF-7 cell with o,verexpressed 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 cells 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.

PURPOSE: The goal of this study was to explore the effects of hsa-let-7g on cell proliferation and apoptosis, and elucidate its role in lung cancer development.MATERIALS AND METHODS: The expression levels of has-let-7g and HOXB1 in tissues and cells were measured by qRT-PCR. An inhibitor of hsa-let-7g or one targeting a control messenger RNA were transfected into A549 and H1944 lung cancer cells, and the effects of hsa-let-7g dysregulation on cell viability and apoptosis were analyzed using CCK-8 and apoptosis detection assays. HOXB1 was confirmed as the target gene of hsa-let-7g, based on luciferase reporter assay results. The relationship between hsa-let-7g and HOXB1 was confirmed by co-transfection of inhibitors of hsa-let-7g and HOXB1 followed by Western blot, CCK-8, and apoptosis detection assays.RESULTS: We observed high expression of hsa-let-7g in lung cancer tissues compared to the corresponding normal tissues, and generally higher expression of hsa-let-7g in patients with advanced tumor classification. The results of CCK-8 and apoptosis detection experiments showed that the inhibition of hsa-let-7g significantly inhibited proliferation of A549 and H1944 cells, but also promoted apoptosis. HOXB1 is a specific target of hsa-let-7g, and downregulation of HOXB1 in lung cancer cells reversed the suppressive effects caused by knocking down hsa-let-7g.CONCLUSION: These data collectively suggest that the expression of hsa-let-7g inhibits lung cancer cells apoptosis and promotes proliferation by down-regulating HOXB1. The results from this study demonstrate the potential of hsa-let-7g/HOXB1 axis as a therapeutic target for the treatment of lung cancer.
Apoptosis ; Blotting, Western ; Cell Proliferation ; Cell Survival ; Classification ; Down-Regulation ; Humans ; Luciferases ; Lung Neoplasms ; Lung ; MicroRNAs ; RNA, Messenger ; Sincalide