Objective: To observe if antibody-targeted immunonanoparticles could internalize into sensitive and multidrug resistance (MDR) cells of human hepatoma; and to study if the immunonanoparticles could reverse the MDR.
Methods: Human hepatoma-specific adriamycin-loaded human serum albumin immunonanoparticles (HAb18-ADR-HSA-NP) were incubated with human hepatoma sensitive cell line (SMMC-7721) or MDR cell line (SMMC-7721/MDR+) and the internalization of immunonanoparticles were observed by laser confocus microscopy, scanning electron microscopy and transmission electron microscopy; MTT colorimetric assay was used for assaying in vitro cytotoxicities of HAb18-ADR-HSA-NP to the resistant variant cells. Then based on these data, IC50 value of the immunonanoparticles and RF (Resistant Factor) of MDR cells were calculated.
Results: Laser confocus microscopy showed that many fluorescent particles (labeled immunonanoparticles) tightly adsorbed to SMMC-7721 cells and were also seen in cytoplasm of SMMC-7721 cells. When incubated with immunonanoparticles at 37 degrees C, many of immunonanoparticles were visualized in cytoplasm of SMCC-7721 or SMCC-7721/MDR+. These immunonanoparticles-contained cells exhibited damaged ultrastructures and the damage degree depended on incubation time. When the human hepatoma cells were pretreated with HAb18 antibody and incubated with immunonanoparticles, few immunonanoparticles were seen in cytoplasm of the cells, suggesting antibody-specific internalization of the immunonanoparticles. Scanning electron microscopy demonstrated specific binding of the immunonanoparticles to the resistant variant cells. That immunonanoparticles exerted enhanced cytotoxicity to the resistant variant cells was demonstrated by a decrease of RF value of MDR cells, compared with free ADR (4.4 vs. 2.1).
Conclusion: Human hepatoma-specific adriamycin-loaded human serum albumin immunonanoparticles could specifically internalize into sensitive or multidrug resistance cells of human hepatoma via antibody direction. The immunonanoparticles could enhance the sensitivity of MDR cells to ADR cytotoxicity, suggesting its reverse effect on MDR.