Synergistic effect of bromocriptine and tumor necrosis factor-α on reversing hepatocellular carcinoma multidrug resistance in nude mouse MDR1 model of liver neoplasm

AIM： To investigate the effect of bromocripUne （BCT） and tumor necrosis factor-α ClNF-α） on hepatocellular carcinoma （HCC） multidrug resistance （MDR） in nude mouse HDR model of liver neoplasm. METHODS： Human hepatocarcinoma cell line HepG2t drug resistant hepatocarcinoma cell line HepG2/adriamycin （ADM） and hepatocarcinoma cell line transfected with TNF-α gene HepG2JADM/TNF were injected into the liver of nude mice via orthotopic implantation and MDR model of liver neoplasm in vivo was established （HepG2t ADM, TNF, BCT groups）. Among these groups, BCT group and TNF group were treated with BCT through gastric canal. Each group was divided into control group and chemotherapy group. Size and weight of the tumor were measured. Furthermore, tumor his~logical character and growth of the nude mice were observed and their chemosensitivity was tested. MDR-associated genes and proteins （MRP, LRP） of implanted tumors were detected by immunohistochemistry, reverse transcriptase polymerase chain reaction, and apoptosis rate of hepatocarcinoma cells was detected by TUNEL assay. RESULTS： The nude mouse model of each cell line was inoculated successfully. The tumor growth rate and weight were significantly different among groups. After chemotherapy, abdominal cavity tumor growth inhibition rate was higher in BCT group （67%） compared to ADM and TNF groups, and similar to HepG2group （54%）. MDRI and LRPmRNA could be detected in all groups, but TNF-α was detected only in TNF and BCT groups. Furthermore, MDR1 and LRP protein expression of tumors in TNF and BCT groups was low similar to HepG2 group. The apoptosis rate of hepatocarcinoma cells was much higher in BCT group than in other groups with TUNEL assay. CONCLUSION： BCT and TNF-a can reverse HCC MDR in nude mouse MDR1 model of liver neoplasm. 2005 The WJG Press and Elsevier Inc. All rights reserved