ABSTRACT
BACKGROUND: To investigate the expression and role of G-protein-signaling modulator 2 (GPSM2) in a CD133+ pancreatic stem cell subset. MATERIALS AND METHODS: Pancreatic cancer stem cells (PCSCs) from the cell line PANC-1 were sorted into CD133+ and CD133- subsets by flow cytometry. The tumorigenic potential of the subsets was assessed by subcutaneous tumor formation experiments in nude mice. Differential expression of GPSM2 was examined by real-time quantitative-PCR (qPCR) and Western blotting. To silence GPSM2 expression, a shRNA lentiviral vector targeting GPSM2 was constructed and stably transfected into CD133+ PCSCs. The inhibitory efficiency of the GPSM2 gene was verified by qPCR and Western blotting. The proliferation, colony formation, and migration abilities of the transfected CD133+ pancreatic cancer cells were assessed by MTT, soft agar colony formation, and Transwell assays. RESULTS: CD133+ and CD133- cell subsets were successfully isolated from PANC-1 cells. The CD133+ subset subcutaneously formed tumors in nude mice that were significantly bigger (343.05±57.59 mm3 vs 176.86±32.58 mm3, P<0.01) and denser (4.13±0.37 g vs 1.07±0.21 g, P<0.01) than those of the CD133- group. The GPSM2 mRNA and protein expression was significantly higher in CD133+ cells than in CD133- cells. Stable downregulation of GPSM2 expression reduced the proliferation, colony formation, and migration abilities of CD133+ PANC-1 cells (P<0.05). CONCLUSION: The CD133+PANC-1 cells have obvious stem cell characteristics and increased GPSM2 expression. Downregulation of GPSM2 significantly reduces the proliferation and migration ability of the cells. Therefore, GPSM2 may provide an important target for regulating PCSCs.
ABSTRACT
PURPOSE: The expression of microRNA-505 (miR-505) has been investigated in various cancers; however, its effect and mechanism in relation to gastric cancer (GC) are yet to be determined. Thus, the current evaluation aimed to examine the expression and potential role of miR-505 in GC. MATERIALS AND METHODS: Quantitative real-time PCR was carried out to analyze miR-505 expression in GC cells and tissues. We observed that miR-505 is differentially expressed in GC cells following transfection of its mimics or inhibitors. Changes in cell invasion, cell proliferation, and epithelial-mesenchymal transition markers were measured. RESULTS: These findings indicated that miR-505 expression is downregulated in both GC cell lines and GC tissues. In addition, knockdown miR-505 induced the invasion and proliferation of GC cells. Transfection of miR-505 mimics led to an elevation in N-cadherin expression but a decrease in E-cadherin expression. Furthermore, we have shown that miR-505 binds to the 3'-UTR region of Polo-like kinase-1. CONCLUSION: Our results indicated that miR-505 suppresses GC cell proliferation and invasion; it may be a valuable candidate gene for seeking therapy strategy for GC.
