Preparation And Peculiar Interaction Of A Low-densitylipoprotein: Doxorubicin Complex With Leukemic Cells

Objective To investigate the feasibility and effectiveness of low-density lipoprotein (LDL) particles as a carrier of a lipophilic anthracycline drug doxorubicin (ADM) for targeting delivery to leukemic cell. Methods Lyophilisation of 2 mg LDL was incubated with 1 mg AD32 in 1ml ether for one hour at room temperature, drying with N2 for 30 min; Adding 10ml PBS(pH 7.4), then the complexes were dialyzed to remove free ADM in LDL buffer at 4 C, finally, to remove the aggregated LDL particle, the complexes was passed through a 0.22um filter. Cytotoxicity of the complex was studied by MTT test in five concentration of 0.02mg/mL, 0.01mg/mL, 0.005mg/mL, 0.0025mg/mL, 0.00125mg/mL respectively, the intracellular ADM content was assayed fluorometrically. Results In higherconcentration (more than 0.01mg/mL) , LDL-ADM presented a greater inhibition of the growth of K562 cells than that of normal PBL, the former is 1.6 times of the latter; when concentration of drug was less than 0.005mg/mL, the inhibition of the growth of K562 had no difference between LDL-ADM and free ADM, and it was similar to that of the bone marrow leukemic cells from patient with M2-subtype. Meanwhile the inhibition of the growth of peripheral blood monocyte from healthy personwas not different between LDL-ADM group and free ADM group. The intracellular ADM content of LDL-ADM group was more than that of free ADM group, when the K562 cell was incubated at 37 C for 0.5h, 1.5h, 2.5h and 3h respectively, and it was elevated with time gone, but the intracellular ADM content of free ADM group elevated quickly within 60min, and didn't increase further after 60min. While the intracellular ADM content of peripheral blood monocyte incubated was similar between LDL-ADM group and free ADM group. Uptake of LDL-ADM in K562 cell was more than that of peripheral blood monocyte, the former is 1.36 times of the latter when cell was incubated for 2h. Conclusion LDL can be used as a effective carrier of ADM to form the LDL-ADM complex. LDL-ADM complex present more cytotoxicity to leukemic cell, but it didn't increase cytotoxicity to peripheral blood monocyte. As a result, cytotoxicity of LDL-ADM complex to leukemic cell is peculiar relatively.