RESUMO
@#Objective: To investigate the relationship between drug resistance and expression of ABC-binding cassette subfamily B member 1 (ABCB1) as well as its promoter methylation in pancreatic cancer. Methods: Fifteen pairs of pancreatic cancerous tissues and corresponding para-cancerous tissues, which were pathologically verified in Fujian Cancer Hospital from August 2015 to August 2018, were collected for this study; in addition, 3 cases of normal pancreatic tissues and pancreatic cancer cell line SW1990 were also collected. Gemcitabine (GEM)-resistant human pancreatic cancer cell line SW1990/GZ was induced by intermittent concentration gradient multiplication method. The expression level ofABCB1 in SW1990 cells, SW1990/GZ cells, pancreatic cancer tissues and apara-cancerous tissues was detected by qPCR. Methylation of ABCB1 promoter region in SW1990 cells, SW1990/GZ cells and pancreatic cancerous tissues was determined by MSP-PCR. Results: Compared with SW1990 cells, the morphology of SW1990/GZ cells showed more vacuoles, more mitotic images, clumpy growth and increased drug resistance (P<0.05). ABCB1 expression in pancreatic cancer tissues was significantly higher than that in para-cancerous tissues (P<0.01). The expression of ABCB1 in SW1990 and SW1990/GZ cells was significantly higher than that in normal pancreatic tissues (P<0.05 or P<0.01), and the expression of ABCB1 in SW1990/GZ cells was higher than that in SW1990 cells (P<0.05). ABCB1 promoters in SW1990, SW1990/GZ cells and normal pancreatic tissues were hypomethylated. Rate of methylation in pancreatic can cerous tissues and normalpancreatic tissues was 6.7%(1/15) and 0.00%(0/3) respectively,and the difference was statistically insignificant (all P>0.05). Conclusion: Increased ABCB1 expression in pancreatic cancer tissues and cells is associated with drug resistance, but its gene expression does not depend on promoter methylation regulation.