High dose glargine afters the expression profiles of microRNAs in pancreatic cancer cells

AIM: To investigate the effect of high dose glargine on the expression profiles of microRNAs in human pancreatic cancer cells. METHODS: Real-time polymerase chain reaction array (RT-PCR) was applied to investigate miRNAs differentially expressed in Sw1990 cells treated with or without 100 IU/L glargine. Stem-loop RT-PCR was used to confirm the results of the array assay in Sw1990 and Panc-1 cells. The effects of miR-95 on cell growth, apoptosis, invasion and migration abilities were respectively examined by CCK8 assay, apoptosis assay, Matrigel invasion and migration assay in Sw1990 and Panc-1 cells. Nude mice xenograft models with Sw1990 cells were built to investigate pancreatic cancer growth in vivo after transfection by the lentivirus pGLV3-GFP-miR-95. RESULTS: Ten miRNAs were significantly up-regulated and 2 miRNAs down-regulated in glargine treated Sw1990 cells when compared with non-treated cells (2.48-fold changes on average, P < 0.01). miR-95, miR-134 and miR-34c-3p are the top three miRNAs regulated by glargine (3.65-fold, 2.67-fold and 2.60-fold changes respectively, P < 0.01) in Sw1990 cells. Stem-loop RT-PCR confirmed that high dose glargine up-regulated the expression of miR-95 and miR-134 in both Sw1990 and Panc-1 cells. The most obvious change is the apparent increase of miR-95. Forced expression of miR-95 significantly increased cell proliferation (Sw1990: 2.510 +/- 0.129 vs 2.305 +/- 0.187, P < 0.05; Panc-1: 2.439 +/- 0.211 vs 2.264 +/- 0.117, P < 0.05), invasion (Sw1990: 67.90 +/- 12.33 vs 47.30 +/- 5.89, P < 0.01; Panc-1: 37.80 +/- 8.93 vs 30.20 +/- 5.14, P < 0.01), migration (Sw1990: 101 +/- 6.00 vs 51.20 +/- 8.34, P < 0.01; Panc-1: 91.80 +/- 9.22 vs 81.50 +/- 7.47, P < 0.01) and inhibited cell apoptosis (Sw1990: 22.05% +/- 1.92% VS 40.32% +/- 1.93%, P < 0.05; Panc-1: 20.17% +/- 0.85% VS 45.60% +/- 1.43%, P < 0.05) when compared with paired negative controls, whereas knockdown of miR-95 obtained the opposite effect. Nude mice xenograft models confirmed that miR-95 promoted the growth of pancreatic cancer in vivo when compared with negative control (tumor volume: 373.82 +/- 23.67 mL vs 219.69 +/- 17.82 mL, P < 0.05). CONCLUSION: These observations suggested that modulation of miRNA expression may be an important mechanism underlying the biological effects of glargine. (C) 2012 Baishideng. All rights reserved.