Antiangiogenic and antitumor activities of berberine derivative NAX014 compound in a transgenic murine model of HER2/neu-positive mammary carcinoma

Berberine is a natural isoquinoline alkaloid with proven antiangiogenic and anticancer activities. We recently demonstrated that berberine and its synthetic derivative 13-(4-chlorophenylethyl)berberine iodide, NAX014, exert antiproliferative activity against HER2-overexpressing breast cancer cells, inducing apoptosis, modulating the expression of cell-cycle checkpoint molecules involved in cell senescence, and reducing both HER2 expression and phosphorylation on tumor cells. In this study we examined the anticancer properties of berberine and NAX014 in a transgenic mouse model which spontaneously develops HER2-positive mammary tumors. Repeated intraperitoneal injections of a safety dose (2.5 mg/kg) of NAX014 delayed the development of tumors, reducing both the number and size of tumor masses. In vivo sidestream dark field videomicroscopy revealed a significant lower vessel density in mammary tumors from NAX014-treated mice in comparison with the control group. Immunohystochemical evaluation using CD34 antibody confirmed the reduced vessel density in NAX014 group. Statistically significant increase of senescence associated β-galactosidase and p16 expression, and reduced expression of heparanase were observed in tumors from NAX014-treated mice than in tumors from control animals. Finally, NAX014 treatment decreased the level of perforine and granzyme mRNA in mammary tumors. Berberine did not show any statistically significant modulation in comparison to control mice.The results of the present study indicate that NAX014 is more effective than berberine in exerting anticancer activity delaying the development of mammary tumors in mice transgenic for the HER-2/neu oncogene. The antitumor efficacy of NAX014 is mainly related to its effect on tumor vascular network and on induction of tumor cell senescence.