Objectives To isolate cancer stem cells (CSCs) in pancreatic cancer cell lines PANC1 and ASPC-1 with serum-free medium( SFM ), and to detect the expression of miR-590-3p in CSCs. Methods PANC1 and ASPC-1 cells was cultured in serum-free medium. The monoclonal formation, differentiation and cell cycle, half inhibitory concentration ( IC50 ), and the expression of the surface markers CD24 + , CD44 + were detected. qRT-PCR was used to detect the expression of miR-590-3p. Results After SFM culture, (0.94 ±0.53 ) ％ of ASPC-1 and (0.57 + 0. 12 ) ％ PANC1 survived, and they formed spheres, and could continuously passage in vitro. Cell spheres differentiation recurred when serum was supplemented in SFM. The G0/G1 stage proportion, CD24+ , CD44 + , CD24+ CD44+ cells proportion, IC50 in ASPC-1 cell were (75.3 ± 5.4)％,0.96％ ～ 2.01％, 27.52％ ～ 34.47％, 0.35％ ～ 0.44％ and (224.37 ± 5.71 ) μg/ml, which were significantly higher than that those in parent cell [ (43.7 ± 3.8 ) ％, 0. 38％ ～ 0.42％, 17.65％ ～ 18.25％,0.05％ ～0.08％, (11.43 ±2.10)μg/ml, P＜0.05]. The G0/G1 stage proportion, CD24+ ,CD44+ ,CD24 +CD44 + cells proportion, IC50 in PANC 1 cell were ( 80. 1 ± 4.7) ％, 5.31％ ～ 9.84％, 72.05％ ～ 93.06％,4.91％ ～5.21％, (296.58±4.27) μg/ml, which were significantly higher than that those in parent cell [ (46.1 ±5.3)％, 4.09％ ～4.97％, 47.71％ ～55.66％, 1.48％ ～2.63％, (26.17 ±3.81)μg/ml, P＜0.05]. The expression of miR-590-3p in ASPC-1, PANC1 spheres was 4.67 and 4.52 times higher than the expression in parent cell lines. Conclusions Pancreatic cancer cell spheres can be isolated from ASPC-1, PANC1 by culture with SFM. miR-590-3p is up-regulated and may play an important role in regulating biological characteristics of pancreatic cancer stem cells.

Drug-metabolizing enzymes, transporters, and nuclear receptors are essential for the absorption, distribution, metabolism, and excretion (ADME) of drugs and xenobiotics. MicroRNAs participate in the regulation of ADME gene expression imperfect complementary Watson-Crick base pairings with target transcripts. We have previously reported that Cytochrome P450 3A4 (CYP3A4) and ATP-binding cassette sub-family G member 2 (ABCG2) are regulated by miR-27b-3p and miR-328-3p, respectively. Here we employed our newly established RNA bioengineering technology to produce bioengineered RNA agents (BERA), namely BERA/miR-27b-3p and BERA/miR-328-3p, fermentation. When introduced into human cells, BERA/miR-27b-3p and BERA/miR-328-3p were selectively processed to target miRNAs and thus knock down and mRNA and their protein levels, respectively, as compared to cells treated with vehicle or control RNA. Consequently, BERA/miR-27b-3p led to a lower midazolam 1'-hydroxylase activity, indicating the reduction of CYP3A4 activity. Likewise, BERA/miR-328-3p treatment elevated the intracellular accumulation of anticancer drug mitoxantrone, a classic substrate of ABCG2, hence sensitized the cells to chemotherapy. The results indicate that biologic miRNA agents made by RNA biotechnology may be applied to research on miRNA functions in the regulation of drug metabolism and disposition that could provide insights into the development of more effective therapies.