Anti-tumor activity and mechanisms of isorhamnetin in combination with sorafenib for renal cancer / 药学学报

ABSTRACT

This study aimed to explore the anti-tumor activity and mechanisms of action of isorhamnetin, a compound isolated from Astragalus membranaceus, in combination with sorafenib for treatment of renal cell carcinoma (RCC). The anti-tumor activity of isorhamnetin in combination with sorafenib was detected by MTT assay with cells in culture or Renca xenograft model in mice. Western blot was used to study the mechanisms of isorhamnetin in combination with sorafenib. Lymphocyte proliferation assay was also used to investigate the effects of the two drugs in combination. The results indicated that isorhamnetin inhibited the proliferation of RCC cells, with IC50 for A498, 786-O and Renca cell lines with being 31.7, 28.8 and 106.0 μmol·L-1, respectively. Isorhamnetin in combination with sorafenib improved the anti-lymphocyte proliferation activity of sorafenib with the IC50 down to 12.0 μmol·L-1. Isorhamnetin inhibited the growth of RCC in mice slightly with the inhibition efficiency at 26.9%. With 50.0 mg·kg-1 isorhamnetin in combination with 20.0 mg·kg-1 sorafenib, the anti-tumor activity of sorafenib was enhanced, with inhibition of growth rate increased to 60.7%. Meanwhile, isorhamnetin in combination with sorafenib could promote the lymphocytes proliferation in Renca xenograft model. Western blot results showed that combination of isorhamnetin and sorafenib could inhibit c-Raf/MEK/ERK and AKT/mTOR signaling pathways. In conclusion, the combination of isorhamnetin with sorafenib could increase the anti-tumor activity of sorafenib in RCC in vitro and in vivo. The mechanisms may be related to the inhibition of c-Raf/MEK/ERK and AKT/mTOR signaling pathways. Procedures for animal study were performed with approval of the Animal Care and Use Committee of the Chinese Academy of Medical Sciences and Peking Union Medical College.