Efficacy of combined axitinib with dacarbazine in a B16F1 melanoma xenograft model

In this study, we evaluated the efficacy and intestinal side effects of the selective inhibitor of vascular endothelial growth factor (VEGF) receptors, axitinib and/or dacarbazine (DTIC), in a B16F1 melanoma xenograft model. C57BL/6 mice were subcutaneously inoculated with B16F1 melanoma cells. The study was randomized into four groups receiving either 0.5% carboxyl methylcellulose, DTIC, axitinib or a combination of DTIC and axitinib. When the experimental period was complete, the tumor tissues from each mouse were excised, photographed and weighed. The tumor and intestinal tissues were harvested with 4% paraformaldehyde, and paraffin-embedded sections were prepared for hematoxylin and eosin staining, immunohistochemical staining (with antibody specific to proliferating cell nuclear antibody) and terminal deoxynucleotidyl-transferase-mediated dUTP nick end labeling assays. The expression of the VEGF and matrix metalloproteinase 9 genes was analyzed using real-time polymerase chain reaction. No significant benefit to treatment with a combination of axitinib and DTIC, as opposed to axitinib alone, was observed; however, the combined treatment did not enhance the level of enteritis compared with that observed in the axitinb group. In addition, axitinib, as a single agent, demonstrated an improved treatment efficacy compared with DTIC. Therefore, axitinib represents a potential novel, efficient and safe anticancer agent, suggesting a possible use for this schedule in treating melanomas that are less sensitive to DTIC.