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

Abstract

To investigate the effect of bromocriptine (BCT) and tumor necrosis factor-alpha (TNF-alpha) on hepatocellular carcinoma (HCC) multidrug resistance (MDR) in nude mouse MDR model of liver neoplasm. Human hepatocarcinoma cell line HepG(2), drug resistant hepatocarcinoma cell line HepG(2)/adriamycin (ADM) and hepatocarcinoma cell line transfected with TNF-alpha gene HepG(2)/ADM/TNF were injected into the liver of nude mice via orthotopic implantation and MDR model of liver neoplasm in vivo was established (HepG(2), 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 histological 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. 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 HepG(2) group (54%). MDR1 and LRPmRNA could be detected in all groups, but TNF-alpha 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 HepG(2) group. The apoptosis rate of hepatocarcinoma cells was much higher in BCT group than in other groups with TUNEL assay. BCT and TNF-alpha can reverse HCC MDR in nude mouse MDR1 model of liver neoplasm.