miR-497 inhibits the growth and metastasis of SGC-7901 human gastric cancer anoikis resistant cells via blocking Wnt/β-catenin signaling pathway / 细胞与分子免疫学杂志

Objective To investigate the effects of microRNA497 (miR-497) on the metastasis of gastric cancer and its possible molecular mechanism. Methods SGC-7901 gastric cancer parent cells were cultured in an ultra-low adhesion environment, and the anoikis resistance model of SGC-7901 cells was created after re-adhesion. Clone formation assay, flow cytometry, TranswellTM test and scratch healing test were used to detect the differences of biological behavior compared with their parent cells. Fluorescence quantitative PCR was performed to detect the expression of miR-497. Western blot analysis was used to detect the changes of key proteins of Wnt/β-catenin signaling pathway and epithelial mesenchymal transformation (EMT) related proteins such as vimentin and E-cadherin. Parent cells and anoikis resistant SGC-7901 cells were transfected with miR-497 inhibitor or miR-497 mimic, and CCK-8 assay was used to detect the proliferation activity. TranswellTM invasion assay was performed to detect the invasion ability of cells. TranswellTM migration test and scratch healing assay was used to determine the migration ability. Western blot analysis was used to detect the expressions of Wnt1, β-catenin, vimentin and E-cadherin. By transfecting miR-497 mimic into the anoikis resistance SGC-7901 cells and inoculating them subcutaneously in nude mice, the changes in the volume and mass of tumor tissues were measured and recorded. Western blot analysis was used to determine the expressions of Wnt1, β-catenin, vimentin and E-cadherin of tumor tissues. Results Compared with the parent cells, the anoikis resistance SGC-7901 gastric cancer cells had faster proliferation rate, stronger colony formation, lower apoptosis rate, stronger invasion and migration ability. The expression of miR-497 was significantly decreased. After down-regulation of miR-497, the proliferation ability, invasion and migration ability were significantly enhanced. The expressions of Wnt1, β-catenin and vimentin increased significantly, while E-cadherin decreased notably. The results of up-regulation miR-497 were the opposite. The tumor growth rate, tumor volume and mass of miR-497 overexpression group were significantly lower than those of control group. The expressions of Wnt1, β-catenin and vimentin decreased significantly, while the expression of E-cadherin increased significantly. Conclusion The expression of miR-497 is low in the anoikis resistance SGC-7901 cells. miR-497 can inhibit the growth and metastasis of gastric cancer cells by blocking Wnt/β-catenin signaling pathway and EMT.

PAUF promotes adhesiveness of pancreatic cancer cells by modulating focal adhesion kinase

Pancreatic cancer is a notorious disease with a poor prognosis and low survival rates, which is due to limited advances in understanding of the molecular mechanism and inadequate development of effective treatment options over the decades. In previous studies, we demonstrated that a novel soluble protein named pancreatic adenocarcinoma up-regulated factor (PAUF) acts on tumor and immune cells and plays an important role in metastasis and progression of pancreatic cancer. Here we show that PAUF promotes adhesiveness of pancreatic cancer cells to various extracellular matrix (ECM). Our results further support a positive correlation of activation and expression of focal adhesion kinase (FAK), a key player in tumor cell metastasis and survival, with PAUF expression. PAUF-mediated adhesiveness was significantly attenuated upon blockade of the FAK pathway. Moreover, PAUF appeared to enhance resistance of pancreatic cancer cells to anoikis via modulation of FAK. Our results suggest that PAUF-mediated FAK activation plays an important role in pancreatic cancer progression.