The Effect of Liposomal Doxorubicin Form on Drug Resistant Tumor Phenotype

Objective: to investigate the influence of liposomal form of doxorubicin (Dox) on drug resistance tumor phenotype and to determine its individual mechanisms. Objects and methods: Dox-resistant Guerin carcinoma rats; human breast cancer MCF-7 cells and Dox-resistant subline MCF-7/Dox. Methods of experimental oncology, cell culture, histological, immunocytochemical; the light and laser confocal microscopy. Results: liposomal Dox significantly inhibits the growth of free Dox resistant strain Guerin carcinoma and leads to pathomorphosis of parenchymal tumors. Free Dox enters the cytoplasm of tumor cells by diffusion, liposomal — by endocytosis. Liposomal form of the drug does not induce the expression of P-gp in tumor cells and thus bypasses the ejection from the cytoplasm by this protein. Conclusions: liposomal Dox form has advantages in terms of free-form cytostatic regarding the accumulation and impact on malignant cells. This leads to long-term accumulation of cytostatic as in the cytoplasm and nucleus of tumor cells with the phenotype of drug resistance.