ABSTRACT
Metadherin (MTDH) is a multifunctional oncogene involved in tumor cell migration and metastasis through regulating a number of oncogenic signaling pathways in various human malignancies. Previous studies have demonstrated that MTDH is overexpressed in human colorectal cancer (CRC) and associated with cancer progression and a poor prognosis. However, the underlying mechanisms remain largely unknown. The present study investigated the expression and role of MTDH in CRC cells as well as the underlying mechanism of this. Western blot analysis and quantitative polymerase chain reaction were conducted to determine protein and mRNA expression of MTDH in three human CRC cell lines. A short hairpin RNA (shRNA) targeting MTDH was introduced into CRC HCT116 cells to stably inhibit MTDH expression. A Cell Counting Kit8 assay, colony formation assay, Transwell assay and flow cytometry were used to investigate the effect of MTDHknockdown on cell proliferation, migration, apoptosis and cell cycle arrest. Western blotting was performed to examine the protein expression levels of cell growth and apoptosisassociated genes. The results demonstrated that MTDH was commonly expressed in CRC cell lines. MTDH silencing significantly suppressed cell growth, colony forming ability and migration while inducing the apoptosis of HCT116 cells. In addition, MTDH depletion induced S phase cell cycle arrest in HCT116 cells. Mechanistically, knockdown of MTDH markedly downregulated the expression of phosphorylated protein kinase B, cMyc, proliferating cell nuclear antigen and Bcell lymphoma 2 (Bcl2) protein in HCT116 cells, and the expression of p53 and Bcl2associated X protein was significantly increased compared with the negative control shRNA group (P<0.05), suggesting that MTDH may function through the expression of numerous types of apoptosisassociated and signaling channel proteins in CRC cells. Taken together, these data indicated that MTDH may serve as a biomarker and candidate therapeutic target for CRC.
Subject(s)
Biomarkers, Tumor/metabolism , Cell Adhesion Molecules/metabolism , Cell Movement , Cell Proliferation , Colorectal Neoplasms/pathology , Proto-Oncogene Proteins c-bcl-2/metabolism , Proto-Oncogene Proteins c-myc/metabolism , Apoptosis , Biomarkers, Tumor/genetics , Cell Adhesion Molecules/antagonists & inhibitors , Cell Adhesion Molecules/genetics , Colorectal Neoplasms/genetics , Colorectal Neoplasms/metabolism , Gene Expression Regulation, Neoplastic , Humans , Membrane Proteins , Proto-Oncogene Proteins c-bcl-2/genetics , Proto-Oncogene Proteins c-myc/genetics , RNA, Messenger/genetics , RNA, Messenger/metabolism , RNA-Binding Proteins , Signal Transduction , Tumor Cells, CulturedABSTRACT
This work aims to study the roles and related mechanisms of six2 in 5-FU sensitivity of hepatocellular carcinoma (HCC) cells. KM-Plotter analysis showed that HCC patients with higher six2 expression levels had shorter overall survival. Six2 expression was higher in clinical HCC tissues than in normal tissues, and was negatively correlated with E-cadherin expression. Additionally, six2 overexpression decreased the sensitivity of HCC cells to 5-Fu, characterized as attenuating 5-FU-induced cell apoptosis and downregulation of cell viability, and promoted HCC cells stemness. Mechanistically, six2 overexpression repressed E-cadherin expression via stimulating promoter methylation of the E-cadherin. And E-cadherin overexpression rescued six2-induced decrease of 5-FU sensitivity and promotion on HCC cells stemness. Therefore, our results suggest that Six2 is negatively correlated with good prognosis and decreases 5-FU sensitivity via suppressing E-cadherin expression in HCC cells.
