Guggulsterone sensitized drug-resistant human hepatocarcinoma cells to doxorubicin through a Cox-2/P-gp dependent pathway.
Previous researches indicated that cyclooxygenase-2 (Cox-2) might be involved in P-glycoprotein (P-gp)-mediated multidrug resistance in hepatocellular carcinoma cells. Doxorubicin-resistant hepatocellular carcinoma PLC/PRF/5 cells (PLC/PRF/5R) and HepG2 (HepG2R) cells were developed in the present study. The modulatory effect of guggulsterone on Cox-2 and P-gp in PLC/PRF/5R and HepG2R cells was investigated. Cells proliferation, Cox-2 and P-gp expression, and prostaglandin E2release were examined using MTT, flow cytometry, western blot and ELISA assays. Small interfering RNA (siRNA) targeted against Cox-2 and multidrug resistance protein (Mdr-1) was used to regulate the expression of Cox-2 and P-gp. The results showed that co-administration of guggulsterone resulted in a significant increase in chemo-sensitivity of PLC/PRF/5R cells to doxorubicin, as compared with doxorubicin treatment alone. When doxorubicin (10µM) was combined with guggulsterone (50µM), the mean apoptotic population of PLC/PRF/5R cells was 20.16%. It was increased by 1.5 times, as compared with doxorubicin (10µM) treatment alone. Furthermore, guggulsterone had significantly inhibitory effect on the levels of Cox-2, P-gp and prostaglandin E2. However, guggulsterone did not show significantly inhibitory effect on the expression of prostaglandin E receptors. In addition, Cox-2 siRNA simultaneously reduced the expression of Cox-2 and P-gp in PLC/PRF/5R cells. Mdr-1 siRNA had no influence on Cox-2, but inhibited P-gp expression. The present study suggested that guggulsterone might enhance the cytotoxic effect of doxorubicin to PLC/PRF/5R cells through a Cox-2/P-gp dependent pathway.
Department of Pharmacy, Shanghai Tenth People's Hospital, Tongji University School of Medicine, 200072 Shanghai, China. Electronic address: xuhongbin@tongji.edu.cn.
Hong-Bin
HB
Xu
Department of Pharmacy, Shanghai Tenth People's Hospital, Tongji University School of Medicine, 200072 Shanghai, China.
Jun
J
Fu
Department of Pharmacy, Shanghai Tenth People's Hospital, Tongji University School of Medicine, 200072 Shanghai, China.
Fang
F
Huang
Department of Scientific Research, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, China. Electronic address: dryujing@alyun.com.
Jing
J
Yu
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism*; D017209:Apoptosis / Q000187:drug effects; D006528:Carcinoma, Hepatocellular / Q000473:pathology*; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D015232:Dinoprostone / Q000378:metabolism; D004317:Doxorubicin / Q000494:pharmacology*; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D004357:Drug Synergism; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D008113:Liver Neoplasms / Q000473:pathology*; D011282:Pregnenediones / Q000494:pharmacology*; D018078:Receptors, Prostaglandin E / Q000378:metabolism
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D011282:Pregnenediones; D018078:Receptors, Prostaglandin E; D004317:Doxorubicin; C023617:pregna-4,17-diene-3,16-dione; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D015232:Dinoprostone
Cyclooxygenase-2; Guggulsterone; Hepatocellular carcinoma