Crebanine N-oxide, a natural aporphine alkaloid isolated from Stephania hainanensis, induces apoptosis and autophagy in human gastric cancer SGC-7901 cells

Objective: To investigate the cytotoxic effects and the potential mechanisms of crebanine N-oxide in SGC-7901 gastric adenocarcinoma cells. Methods: The cytotoxicity of crebanine N-oxide was evaluated by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay and cellular morphology was observed under a microscope. Cell apoptosis was determined by flow cytometry using propidium iodide staining. The expression levels of apoptotic-related proteins, cleaved caspase-3, cytochrome C, p53 and Bax, and autophagy-related proteins p62, beclin1 and LC3 were detected by Western blotting assays. Results: Crebanine N-oxide treatment significantly inhibited the proliferation of SGC-7901 cells in a dose-dependent and time-dependent manner via induction of G

TALEN-mediated MYH9 Knock-down and its influence on cell cycle and apoptosis of MGC803 cell line / 南方医科大学学报

<p><b>OBJECTIVE</b>To construct a MYH9 gene knockout model in MGC803 cell line using transcription activator-like effector nuclease (TALEN) and observe its effect on cell cycle and apoptosis.</p><p><b>METHODS</b>According to FastTALE(TM) TALEN Kit, we designed TALEN pairs and constructed the plasmids targeting to MYH9 gene. After detecting their activity in MGC803 cells by plasmid transfection, DNA sequencing, RT-PCR and western blot, we selected the monoclonal cells and studied the changes in the cell cycle and apoptosis.</p><p><b>RESULTS</b>MYH9 gene could not be knocked out but knocked down in selected MGC803 monoclonal cells, which caused cell cycle arrested at G2/M phase (P<0.05) and a significant increase in the cell number with early apoptosis (P<0.01).</p><p><b>CONCLUSION</b>We successfully generated a MYH9 knockdown model in MGC803 cell lines by TALEN, which could be in favor of MYH9 function study in gastric cancer.</p>

Role of CTHRC1 in proliferation, migration and invasion of human colorectal cancer cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the expression of collagen triple helix repeat containing 1 (CTHRC1) in colorectal cancer and study its role in regulating the biological behaviors of colorectal cancer LoVo cells in vitro.</p><p><b>METHODS</b>Real-time PCR and Western blotting were used to detect the expressions of CTHRC1 in colorectal cancer tissue and paired adjacent nontumorous tissue and in 5 colorectal cancer cells. pGPU6-CTHRC1-shRNA was transfected into LoVo cells and the changes in cell proliferation was assessed using cell counting kit-8 (CCK8) assay; the changes in cell migration and invasion were investigated using Transwell assay; plate colony forming test was used to evaluate the adhesion and colony forming activity of the cells. Western blotting was used to analyze the changes in the expressions of the related pathway markers.</p><p><b>RESULTS</b>The relative expression of CTHRC1 mRNA in the cancer tissue specimens was 0.0411∓0.054, significantly higher than that in the adjacent tissues (P=0.016); this result was consistent with that of the protein assay. SW620 and LoVo cells showed obviously higher expressions of CTHRC1 than HT29 and SW480 cells at both mRNA and protein levels. LoVo cells transfected with CTHRC1 shRNA exhibited significantly suppressed proliferation, migration, invasion and colony-forming ability (P<0.05) and lowered expression of phosphorylated ERK1/2 (P-ERK1/2), but the expression of total ERK1/2 showed no obvious changes. CTHRC1 inhibition caused reverse epithelial-mesenchymal transition LoVo cells shown by increased E-cadherin expression and decreased expressions of N-cadherin, vimentin, and β-catenin.</p><p><b>CONCLUSION</b>CTHRC1 is up-regulated in colorectal cancer tissues and SW620 and LoVo cells to promote the cell proliferation, migration, invasion and colony formation. CTHRC1 can enhance epithelial-mesenchymal transition of colorectal cancer cells by activating ERK1/2 to promote tumor cell metastasis and invasion.</p>