HPMA copolymer–anticancer drug–OV-TL16 antibody conjugates. 3. The effect of free and polymer-bound Adriamycin on the expression of some genes in the OVCAR-3 human ovarian carcinoma cell line

Abstract

The effect of an N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer–Adriamycin–OV-TLl6 antibody conjugate [P(GFLG)–ADR–Ab] on OVCAR-3 human ovarian carcinoma cells was studied. A nontargeted HPMA copolymer–ADR conjugate (P(GFLG)–ADR) and free ADR were the controls. The IC 50 doses were 0.65, 3.0, and 65 μM for free ADR, targeted P(GFLG)–ADR–Ab conjugate, and nontargeted P(GFLG)–ADR conjugate, respectively. These differences reflect the different mechanisms of cell entry of the compounds evaluated. Free ADR and HPMA copolymer–ADR conjugates had different impacts on the expression of MDR1, MRP, c- fos, c- jun, and bcl-2 genes which encode the P-glycoprotein ( MDR1) and the multidrug resistance-associated protein ( MRP) efflux pumps, and play an important role in cell death signaling pathways (c- fos, c- jun, and bcl-2). Whereas high doses of free ADR induced MDR1 gene expression, HPMA copolymer-bound ADR appeared to be without effect. On the contrary, expression of the MRP gene was not influenced by free ADR, whereas HPMA copolymer–ADR conjugates seemed to suppress the gene expression in a concentration-dependent manner. There were differences in the expression of c- fos, c- jun, and bcl-2 genes after the incubation of OVCAR-3 cells with free and HPMA copolymer-bound ADR indicating differences in activation of cell death signaling pathways.