| OBJECTIVES: Chansu (toad venom) is a traditional Chinese medicine. Its raw materials are white seriflux secreted from glandular organ of the skin of back and post aurem in toad. Chansu has effect of anti-tumor, anti-radiation, anti-inflammatory, enhancing immunity and anesthesia[1]. Chansu injection is prepared by using the whole skin of China toads as main raw materials, which can treat serious liver, gastric, breast and prostatic cancers[2,3]. Chansu injection has showed inspiriting anti-tumour activity as reported by many researches. However, there are anti-tumor mechanisms still remains unknown. This study is to investigate the effect and functional mechanism of Chinese drug Chansu injection on reversal multidrug resistance of HL60/ADM cell line.METHOD: MTT cell viability assay was used to verify the effective reversal concentration by CHS in HL-60/ADM cell line. MTT assay and flow cytometry were used to determine the growth inhibition and cell cycle intervention effects of CHS. The concentrations of intracelluar Adriamycin have been determined by high performance liquid chromatography. The expression of MRP at mRNA level were also determined by RT-PCR before and after CHS exposure. Expression of NF-κB,MRP,GST-πand iNOS in CHS-induced cells were detected by immunocytochemical method.RESULTS: CHS in vitro remarkably enhanced the sensitivity of HL60/ADM cells to Adriamycin. The IC50 of HL60/ADM cells to adriamycin was significantly reduced as compared with that of the control . The amount of Adriamycin accumulated in the HL60/ADM cells was increased by HPLC. The number of cells in the G0/G1 and G2/M phase consistently increased with a concomitant decrease in the S phase in cells treated by CHS . Expressions of MRP mRNA were lower in the HL60/ADM cell which treated with drugs . The expression of GST-πand MRP proteins were down-regulated by CHS. However, the expression of iNOS and NF-κB proteins were up-regulated , so as to reverse MDR.CONCLUSIONS: CHS could partly reverse MDR in HL60/ADM cells. The reversal effect of CHS may be attributed to enhancement of drug accumulation in resistant cells by down-regulating of MRP and GST-π. CHS could be a candidate of effective multidrug resistance-reversing agent with low toxicity in leukemia chemotherapy. |
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