ABSTRACT
Breast cancer, which derives from the epithelium of the mammary glands, is one of the most common cancers diagnosed in women globally. To date, the authors of many studies have reported that the deregulation of microRNAs (miRNAs) plays a crucial role in the occurrence, development, and metastasis of tumors. Here, we discovered that miR-660-5p was upregulated in the breast cancer cell lines MCF7 and MDA-MB-231 compared with that in the normal control cell line CCD-1095Sk. We then inhibited the expression of miR-660-5p to investigate its biological function in cancer development, progression, and metastasis. We determined the changes in the levels of expression of transcription factor CP2 (TFCP2) and CDKN1A to further clarify the specific mechanism involved. The results showed that downregulation of miR-660-5p significantly suppressed the proliferation, migration, and invasion of MCF7 breast cancer cell. Moreover, inhibition of miR-660-5p promoted cell cycle G1 arrest and reduced apoptosis in breast cancer cells. The specific mechanism studies confirmed that TFCP2 was a direct downstream target of miR-660-5p. Aberrant expression of miR-660-5p repressed TFCP2 expression, whereas inhibition of miR-660-5p decreased TFCP2 protein expression, which is a vital factor in the downstream signaling pathway. In conclusion, miR-660-5p can regulate the proliferation, migration, and invasion of human breast cancer cells, and is a novel potential therapeutic target for the clinical treatment of breast cancer.
Subject(s)
Cell Movement/genetics , Cell Proliferation/genetics , Gene Expression Regulation, Neoplastic , MicroRNAs/genetics , Apoptosis/genetics , Blotting, Western , Breast Neoplasms/genetics , Breast Neoplasms/metabolism , Breast Neoplasms/ultrastructure , Cell Line, Tumor , Cyclin-Dependent Kinase Inhibitor p21/genetics , Cyclin-Dependent Kinase Inhibitor p21/metabolism , DNA-Binding Proteins/genetics , DNA-Binding Proteins/metabolism , Down-Regulation , G1 Phase Cell Cycle Checkpoints/genetics , Humans , MCF-7 Cells , Microscopy, Electron , Neoplasm Invasiveness , Neoplasm Metastasis , Reverse Transcriptase Polymerase Chain Reaction , Transcription Factors/genetics , Transcription Factors/metabolismABSTRACT
Abnormal expression of the kallikrein (KLK) family of serine proteases closely correlates with onset, progression, and prognosis of endocrine gland-related malignant tumors. The aim of this study was to evaluate how downregulation of KLK12 influenced cell cycle and proliferation of the AGS gastric cancer cell line. KLK12 was detected by western blot in GES-1 normal gastric epithelial and AGS cells. AGS cells were transfected with KLK12 siRNA, a negative control siRNA, or subjected to a mock transfection, following which, we assessed mRNA and protein levels, cell proliferation, cell migration, and cell cycle progression. We found that KLK12 levels were significantly higher in AGS cells than in GES-1 cells. Transfection of AGS cells with KLK12 siRNA led to downregulation of KLK12 mRNA and protein expression, reduced cell proliferation (0.47 ± 0.03 vs 0.92 ± 0.04, P < 0.01), and lower cell counts (3.92 ± 0.25 x 105 vs 5.47 ± 0.50 x 105, P < 0.01) with respect to the negative control. We observed that KLK12 siRNA increased the number of AGS cells in G0/G1 and reduced those in S phase. Furthermore, downregulation of KLK12 in AGS cells decreased their ability to penetrate the membrane in a migration assay (P < 0.05). In conclusion, KLK12 siRNA inhibited the proliferation and migration of AGS gastric cancer cells and caused their arrest in the G0/G1 phase of the cell cycle.