Significance of acid sphingomyelinase and ceramide in inducing gemcitabine-resistant pancreatic cancer cell line PANC-1

Abstract

Objective To establish gemcitabine-resistant pancreatic cancer cell line PANC-1/ gem and discuss its biological characters and drug resistance mechanism. Methods gemcitabine-resist-ant pancreatic cancer cell line was obtained by culture of pancreatic cancer cell line PANC-1 in vitro with intermittently increasing the concentration of gemcitabine in the culture medium for 24 weeks. After that, TUNEL technique was employed to detect the apoptosis. Meanwhile, its drug sensitivity as well as the expression of sphingomyelinase, contents of C2-ceramide were determined respectively. Results Drug-resistant PANC-1/Gem cell was successfully induced with gemeitabine for 24 weeks. The IC_(50) increased from (8.13±0.85)μg/ml in PANC-1 to (285.40±34.83)μg/ml in PANC-1/Gem. Compared with the normal pancreatic cancer cell line PANC-1, the drug resistance indexes of PANC-1/gem to gemcitabine was 35.1 and the apoptosis rate was reduced from 6.21 to 2.74%. The ex-pression of sphingomyelinase was lower than that of pancreatic cancer cell line PANC-1, and the con-tents of ceramide was reduced from (364.95±46.11 pmol/mg protein) to (120.61±20.07 pmol/mg protein). Conclusion The durg resistance of gemcitabine to pancreatic cancer cell line is positively rel-evant to the low expression of acid sphingomyelinase as well as ceramide deficiency. Key words: Pancreatic neoplasms; Gemcitabine; Drug resistance; Acid sphingomyeli-nase; Ceramide