[Establish a gemcitabine-resistant pancreatic cancer cell line SW1990/GZ and research the relationship between SW1990/GZ and pancreatic cancer stem cell].

Objectives To establish a gemcitabine-resistant pancreatic cancer cell line SW1990/ GZ,and to explore the relationship between drug-resistant cell line SW1990/GZ and pancreatic cancer stem cell. Methods Gemcitabine-resistant pancreatic cancer cell line SW1990/GZ was obtained by treating parental cell line SW1990 in vitro with increasing dosage of gemcitabine in culture medium intermittently for 24 weeks. Stable cultures were obtained which were 77. 2-fold increased in resistance relative to parental cells. Gene expressions of ABCB1/MDR1, ABCC1/MRP and ABCG2/BCRP were determined by real-time PCR. Tumorigenic potential was performed by nude mice xenograft transplant experiments. Side population analysis and CD24CD44 positive cells explore were determined by flow cytometry to examine cancer stem cell proportion. Results Gemcitabine-resistant cell line SW1990/GZ underwent obvious morphological and functional changes. Compared with the parental cell line,SW1990/GZ cell was small and turned into round shape. SW1990/GZ had a higher gene expression level of ABCB1/MDR1, ABCC1/MRP and ABCG2/BCRP than SW1990(P <0. 01). Nude mice xenograft transplant experiments showed that only 1 x 105 SW1990/GZ cells were sufficient for tumor formation, whereas an injection of 1 x 105 SW1990 cells did not initiate tumors. Flow cytometry analysis showed that SP proportion in SW1990/GZ was (11.0±1.0)%, whereas in parental SW1990 it was ( 4. 6 ± 0. 9 ) % , CD44CD24 positive cells was (8. 73±0. 81) % in SW1990/GZ, whereas (1.1±0. 4)% in SW1990. Conclusions Gemcitabine-resistant cell line SW1990/GZ has a higher proportion of pancreatic cancer stem cells compared to its parental cell line SW1990. CD44 is mainly responsible for acquired drug resistance,which can be a potential target to overcome acquired drug resistance in pancreatic cancer. Key words: Pancreatic neoplasms; Drug resistance, neoplasm; Tumor stem cell; Antigens, CD44