Objective: The purpose of this study was to examine the effect of gemcitabine(GEM) on micro RNA-218(mi R-218) expression in human pancreatic cancer cells.Methods: Quantitative reverse transcription polymerase chain reaction(q RT-PCR) was performed to examine the differences in mi R-218 expression between the GEM-sensitive Bx PC-3 pancreatic cancer cells and GEM-resistant PANC-1 cells. The effect of GEM on the expression of mi R-218 in PANC-1 cells was also investigated. PANC-1 cells were transfected either with HMGB1 si RNA to knock down the expression of HMGB1 or with the recombinant HMGB1 expression vector(pc DNA3.1-HMGB1) to overexpress HMGB1. The effect of ectopic expression of HMGB1 on the apoptosis of mi R-218-transfected and GEMtreated PANC-1 cells was examined by flow cytometric analysis.Results: The mi R-218 expression level was lower in GEM-resistant PANC-1 cells compared to GEMsensitive Bx PC-3 cells(P<0.05). The percentage of apoptotic PANC-1 cells was significantly increased in the mi R-218 mimic + GEM group compared to the mimic ctrl + GEM group and the normal control group(P<0.01). The HMGB1 expression level was markedly decreased in PANC-1 cells transfected with HMGB1 si RNA but was significantly increased in PANC-1 cells transfected with the recombinant HMGB1 expression vector, pc DNA3.1-HMGB1(P<0.01). The proportion of apoptotic PANC-1 cells was significantly lower in the mi R-218 mimic + GEM + pc DNA3.1-HMGB1 group compared to the mi R-218 mimic + GEM + HMGB1 si RNA group(P<0.01).Conclusions: The expression level of mi R-218 was downregulated in the GEM-resistant cell line. mi R-218 promoted the sensitivity of PANC-1 cells to GEM, which was achieved mainly through regulating the expression of HMGB1 in PANC-1 cells.
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