Antitumor efficacy of recombinant human interleukin-2 combined with sorafenib against mouse renal cell carcinoma.

OBJECTIVE Recombinant human interleukin-2 (rhIL-2) has been clinically used in the treatment of renal cell carcinoma (RCC). Sorafenib, a multi-targeted kinase inhibitor, has been approved for RCC as well as IL-2. The purpose of this study was to evaluate the antitumor efficacy of IL-2 combined with sorafenib in three different murine renal cancer models using Renca cells. METHODS We established the subcutaneous tumor model by inoculating wild-type Renca cells into the backs of BALB/c mice, the pulmonary metastatic tumor model by an intravenous injection of luciferase-expressing Renca cells into the tail vain and the orthotopic tumor model by injecting luciferase-expressing Renca cells into the renal subcapsule. These tumor-bearing mice were treated intra-peritoneally with rhIL-2 and/or per os with sorafenib. The antitumor efficacy was evaluated by measuring the tumor size of the subcutaneous tumor or photon intensity of the pulmonary metastatic tumor and the orthotopic tumor. RESULTS When rhIL-2 was combined with sorafenib, the antitumor efficacy was significantly augmented in comparison with either rhIL-2 or sorafenib alone in all the models. Sorafenib did not inhibit rhIL-2-induced natural killer cell expansion and rhIL-2 had no effect on the anti-angiogenic activity of sorafenib. CONCLUSIONS The results suggest that the combination of rhIL-2 and sorafenib may offer significant potential as a novel therapeutic approach for patients with RCC.