ABSTRACT
<p><b>OBJECTIVE</b>To investigate the effects of the novel proteasome subunit Adrm1 knockdown by RNA interference on proliferation of colorectal cancer cells.</p><p><b>METHODS</b>The shRNA eukaryotic expression vector against Adrm1 was constructed and transfected into colon cancer RKO cells. The Adrm1-shRNA stable transfected clones were selected. Experimental cells were divided into 3 groups: the experimental group containing stable Adrm1-shRNA transfected cells, the control group containing only RKO colon cancer cells and stable empty vector transfected control group. The Adrm1 protein expression level was analyzed by Western blot. The colony-forming ability of the three groups was assessed by soft agar assay. The cell proliferation and apoptosis were analyzed by methyl thiazolyl tetrazolium (MTT) method and in situ end labeling (TUNEL) assay. Cell cycle changes were assayed by flow cytometry.</p><p><b>RESULTS</b>Adrm1-shRNA effectively suppressed Adrm1 expression in the experimental group. Silencing of Adrm1 in RKO cells significantly inhibited their anchorage-independent growth, only occasional individual colonies were formed. The apoptosis rate of experimental group was (12.4 +/- 1.1)%, significantly higher than that of the stable empty vector transfected control group. The proportion of G(0)/G(1) and S/G(2) phase cells in the experimental group was (41.2 +/- 1.1)% and (58.8 +/- 1.1)%, respectively. The cells were arrested at G(1) phase. In addition, Adrm1 RNA interference combined with 5-Fu treatment significantly suppressed colorectal cancer cell growth in vitro.</p><p><b>CONCLUSION</b>Silencing of Adrm1 by RNA interference can significantly suppress proliferation of RKO cells through inducing apoptosis and arresting the cell cycle. The combined application of Adrm1 RNA interference and chemotherapy may become as a novel therapeutic strategy for Adrm1 overexpressed colorectal cancer.</p>
Subject(s)
Humans , Antimetabolites, Antineoplastic , Pharmacology , Apoptosis , Cell Cycle , Cell Line, Tumor , Cell Proliferation , Colorectal Neoplasms , Metabolism , Pathology , Drug Resistance, Neoplasm , Fluorouracil , Pharmacology , Genetic Vectors , Membrane Glycoproteins , Genetics , Metabolism , Plasmids , RNA Interference , RNA, Small Interfering , Genetics , TransfectionABSTRACT
<p><b>OBJECTIVE</b>To investigate the correlation between the proteasome subunit PSMA7 expression in colorectal cancer and its role in liver metastasis.</p><p><b>METHODS</b>To identify the PSMA7 protein expression in 62 primary site colorectal cancers, 34 lymph node metastatic sites and 13 liver metastatic sites by immunohistochemistry and clarify the correlation of its expression with the clinicopathological parameters.</p><p><b>RESULTS</b>High expression of PSMA7 was detected in 38.7% (24/62) of primary site colorectal cancer, 52.9% (18/34) of lymph node metastatic sites and 100% (13/13) liver metastatic sites but not in the normal colorectal tissue. High expression of PSMA7 was significantly correlated with liver metastasis (P = 0.028). The survival rate was significantly lower in patients with high expression of PSMA7 than in those with low expression of PSMA7 (P = 0.0008). As well, in multivariate analysis, PSMA7 expression demonstrated to be an independent prognostic factor (P = 0.004, relative risk 5.057; 95% confidence interval, 1.682-15.201).</p><p><b>CONCLUSION</b>PSMA7 may play an important role in the colorectal cancer progression. Evaluation of PSMA7 expression in primary colorectal cancer at the time of surgery might be a valuable test in defining patients with a high risk of developing liver metastasis.</p>