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Objective:To explore the expressions of long non-coding RNA LINC00673 and ISG15 protein in pancreatic cancer and their clinical significances.Methods:The clinical data of 57 patients diagnosed as pancreatic ductal carcinoma (PDAC) at the Affiliated Cancer Hospital of Xiangya Medical College of Central South University from January 2014 to December 2018 were retrospectively analyzed. The relative expressions of LINC00673 in pancreatic cancer tissues and paracancerous normal tissues (within 3 cm from the edge of cancer tissues) were examined by using quantificational reverse transcription-polymerase chain reaction (qRT-PCR). The ISG15 protein expressions in pancreatic cancer tissues and paracancerous normal tissues were examined by using immunohistochemistry. The difference in LINC00673 expression between ISG15 protein positive and negative patients was compared. The correlation between LINC00673 and ISG15 protein expressions in pancreatic cancer was analyzed by Spearman rank correlation analysis. Moreover, the correlations of LINC00673 and ISG15 protein expressions with clinical stage and pathological classification of pancreatic cancer patients were analyzed.Results:The positive expression of ISG15 protein in pancreatic cancer tissues was 40.4% (23/57), which was higher than that in paracancerous normal tissues [15.8% (9/57)] ( χ2 = 7.90, P = 0.004), and the relative expression of LINC00673 in pancreatic cancer tissues was 0.99±0.36, which was lower than that in paracancerous normal tissues (1.26±0.41) ( t = 4.80, P < 0.001). For 23 (40.4%) ISG15-positive patients and 34 (59.7%) ISG15-negative patients, the relative expression of LINC00673 was 0.77±0.46 and 0.45±0.27 ( P < 0.001). Spearman analysis showed that there was a correlation between LINC00673 and ISG15 protein expressions ( ρ = -0.429, P = 0.001). The relative expression of LINC00673 decreased in patients with low differentiated or undifferentiated tumor, vascular invasion and lymph node metastasis (all P < 0.05), but there was no correlation between LINC00673 expression and patients' age, tumor site, preoperative CA199 level, and TNM stage (all P > 0.05); ISG15 protein expression increased in patients with low differentiated or undifferentiated tumor, TNM stage Ⅲ-Ⅳ, vascular invasion and lymph node metastasis (all P < 0.05), but there was no correlation between ISG15 protein expression and patients' gender, age, tumor site, and preoperative CA199 level (all P > 0.05). Conclusions:The expression of LINC00673 in pancreatic cancer is related to vascular invasion, tumor differentiation degree and lymph node metastasis, and the expression of ISG15 in pancreatic cancer is related to vascular invasion, tumor differentiation degree, lymph node metastasis and TNM stage. The combined detection of LINC00673 and ISG15 protein could be a valuable prognostic indicator for pancreatic cancer. The therapies targeting LINC00673 and ISG15 protein signaling pathways are expected to be a potential option for immunotherapy of pancreatic cancer.
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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 β-catenin and EZH2 proteins. Conclusion: Overexpression of Linc00673 may promote proliferation and inhibit apoptosis of MGC-803 cells through PI3K/Akt signaling pathway.