Objective: To investigate the effect of anti-cancer drugs on the expression of B-cell integration cluster (BIC) RNA/miRNA-155 in human pancreatic cancer PANC-1 cells.
Methods: PANC-1 cells were treated with different concentrations of anti-cancer drugs. Total RNA of the treated cells were harvested and the expression levels of BIC RNA and mature miR-155 were quantified by using Taqman FAM/MGB probes on a real-time PCR system. Relative quantification was carried out using the DeltaDeltaCt method. A PI3K-related kinases inhibitor was used to determine whether these kinases were involved in the regulation of BIC RNA.
Results: The expression of BIC RNA was strongly induced by anti-cancer drugs. When PANC-1 cells were treated by gemcitabine with concentrations of 1.0, 2.5, 5.0, 10.0 mg/L for 48 h and 72 h, the level of BIC RNA (48 h: 37.1 +/- 4.1, 29.0 +/- 5.7, 21.0 +/- 7.6, 40.4 +/- 9.0, 72 h: 27.7 +/- 3.1, 43.1 +/- 1.2, 31.8 +/- 5.4, 23.1 +/- 1.4) were significantly higher than that of the control (48 h: 1.6 +/- 1.1, 72 h: 1.0 +/- 0.1, all P < 0.05). 5-FU (10 mg/L, 48 h) and bleomycin (100 mg/L, 48 h) also induced BIC RNA up-regulation (5.2 +/- 1.1 vs 1.7 +/- 0.7, 11.5 +/- 0.7 vs 1.7 +/- 0.7, both P < 0.05). When PANC-1 cells treated with 1.0, 2.5, 5.0, 10.0 mg/L gemcitabine for 72 h, the level of miR-155 (2.21 +/- 0.40, 1.86 +/- 0.03, 2.47 +/- 0.04, 3.24 +/- 0.05) also higher than that of the control (1.11 +/- 0.09, P < 0.05), while no change was observed when the cells only treated for 48 h. Further study showed gemcitabine-induced BIC RNA up-regulation was inhibited by wortmannin, a specific PI3K inhibitor, the expression levels of BIC RNA of 1 micromol/L wortmannin + 5 mg/L gemcitabine group and 10 micromol/L wortmannin + 5 mg/L gemcitabine group were 5.34 +/- 1.11 and 1.26 +/- 0.07, lower than that of 5 mg/L gemcitabine group (11.82 +/- 3.11, P < 0.05).
Conclusions: BIC RNA is strongly induced by anti-cancer drugs in PANC-1 cells and the levels of miR-155 also slightly increase. PI3K pathway is involved in gemcitabine-induced BIC RNA up-regulation.