[Effects of long-chain noncoding RNA Linc00673 overexpression on proliferation and apoptosis of gastric cancer cell line MGC-803].

Objective: To investigate the effects of long-chain noncoding RNA Linc00673 overexpression on proliferation and apoptosis of gastric cancer cells and its mechanisms. Methods: The recombinant lentivirus expressing plasmid pLVX-Linc00673 and the control empty plasmid pLVX-NC were packaged and amplified in 293T cells, and the recombinant lentivirus was transfected into gastric cancer cell line MGC-803 to establish a cell line stably overexpressing Linc00673. The expression of Linc00673 gene was detected by real-time fluorescence quantitative PCR. The growth and proliferation of cells were observed by MTT assay and clone formation assay. Cell cycle and apoptosis were detected by flow cytometry. The expressions of cell cycle related regulatory genes were detected by qPCR. The expressions of key molecules in the PI3K/Akt signaling pathway and tumor proliferation related proteins were detected by Western blot. Results: The expressions of Linc00673 in gastric cancer cell line MGC-803, BGC-823 and AGS were significantly higher than that in normal gastric mucosa cell line GES-1 (P＜0.05). MGC-803 cell line with stable overexpression of LINC00673 was established, and the expression level of LincC00673 was 200 times higher than that of the control empty carrier group. Overexpression of Linc00673 promoted proliferation of MGC-803 cells (P＜0.05) and clone formation (P＜0.05), inhibited cell apoptosis and affected the G1→S phase progression of cell cycle (P＜0.01). Overexpression of Linc00673 could affect the expressions of cell cycle regulatory gene CCNG2, P19 and CDK1 in MGC-803. Western blot showed that Linc00673 overexpression not only promoted the expressions of the key molecule pAkt in PI3K / Akt signaling pathway and its downstream target NF-κ B and Bcl-2 protein, but also up regulated the expressions of tumor related factors ß-catenin and EZH2 proteins. Conclusion: Overexpression of Linc00673 may promote proliferation and inhibit apoptosis of MGC-803 cells through PI3K/Akt signaling pathway.

CHMP4C regulates lung squamous carcinogenesis and progression through cell cycle pathway.

BACKGROUND: Lung cancer is a common kind of human malignancies. Lung squamous cell carcinoma (LUSC) is a key subtype of lung cancer. Cell cycle plays an important role in the development and occurrence of LUSC, however, there is still a lack of cell cycle-related genes in LUSC diagnosis and prediction of prognosis. METHODS: We identified differentially expressed genes (DEGs) with "limma" package in R software, and determined the biomarkers of LUSC in diagnosing by performing receiver operating characteristic (ROC) curve analysis, the biomarker effectiveness in diagnosing LUSC was assessed by performing five-fold cross-validation with logistic regression. Kaplan-Meier plot and the nomogram assessed the relationship between the biomarker and patient survival, and WB and qRT-PCR detected the biomarker expression in cells and tissues. Flow cytometry detects the role of the biomarker in the cell cycle. RESULTS: Integration analysis with The Cancer Genome Atlas (TCGA) database obtained a unique gene related to cell cycle in LUSC (Charged multivesicular body protein 4C, CHMP4C), and the protein of CHMP4C was highly expressed in LUSC tissues. ROC analysis indicated that CHMP4C was a biomarker for the diagnosis of LUSC. Bioinformatic analysis indicated that CHMP4C might be associated with cell cycle in LUSC. CHMP4C knockdown resulted in S-phase arrest of cells with LUSC. According to the survival rate analysis, CHMP4C overexpression indicated poor prognosis in patients with LUSC. CONCLUSIONS: CHMP4C regulates the proliferation process of tumor cells through the cell cycle. It can be used as a potential diagnostic and prognostic biomarker for LUSC.