Preparation Of ADM-loaded Immunoliposomes And Reversion Of MDR Of Human Lung Carcinoma In Vitro

Objective: Preparation of ADM-loaded immunoliposomes and examine the cytotoxicity of immunoliposomes on targeting cells and reversion of MDR of human lung carcinoma in vitro. Methods: the liposomes were prepared by the method of ultrosonic agitation, then entrapping driamycin (ADM) into liposomes by a remote loading technique. The entrapping rate of ADM was determined by Visible and Ultraviolet Spectroscopy after the free drug molecules was separated from driamycin liposomes (ADMLs) on a sephadex G-50 minicolumn. The preliposomes, which were made into immunoliposomes by conjugating monoclonal antibodies through glutaraldehyde, were prepared from liposomes by freeze-drying technology. The study of the cytotoxicity of ADMILs and ADMLs on SPC-A1/TAX cell lines and reversion of MDR were determined by measuring the inhibition of cell growth using the MTS assay, and the amount of intracellular ADM accumulation was determined by flow cytometry. Results: When the quantity of phosphatide (the concerntration of phosphotide in chloroform is 4.5g/100ml) is 35ml,the quantity of ADM (the concerntration of ADM in water is 15mg/ml) is 450mg,and supersonicing time in ice-bath is 15 minutes, the entrapping rate of ADM in liposomes is 98 percent. We prepared preliposomes from liposomes by freeze-drying technology and waterized them, which entrapping rate of ADM is 90.5 percent. The waterized preliposomes were linked with MRP monoclonal antibody. Using SPC-A1/TAX as targeting cells, we examined the toxicity of immunoliposomes on targeting cells. The death rate of targeting cells after action for 48 hours is 69 percent, the cytotoxicity of ADMILs to cancer cells were 7.45 times more sensitive than that of free ADM and ADMLs were 4.28,the increased sensitivity of MDR cells to ADMILs and ADMLs was accounted for by a remarkable increase intracellular ADM accumulation. Conclusions: The entrapping rate of liposomes is comparatively high. And the immunoliposomes bearing MRP prepared from preliposomes which come from preliposomes by freeze-drying technology was effective to reverse MDR of human lung carcinoma. ADMILs showed an increased cytotoxicity towards SPC-A1/TAX cells compared to ADMLs and free driamycin.