CS2164, a novel multi‐target inhibitor against tumor angiogenesis, mitosis and chronic inflammation with anti‐tumor potency

Although inhibitors targeting tumor angiogenic pathway have provided improvement for clinical treatment in patients with various solid tumors, the still very limited anti‐cancer efficacy and acquired drug resistance demand new agents that may offer better clinical benefits. In the effort to find a small molecule potentially targeting several key pathways for tumor development, we designed, discovered and evaluated a novel multi‐kinase inhibitor, CS2164. CS2164 inhibited the angiogenesis‐related kinases (VEGFR2, VEGFR1, VEGFR3, PDGFRα and c‐Kit), mitosis‐related kinase Aurora B and chronic inflammation‐related kinase CSF‐1R in a high potency manner with the IC (50) at a single‐digit nanomolar range. Consequently, CS2164 displayed anti‐angiogenic activities through suppression of VEGFR/PDGFR phosphorylation, inhibition of ligand‐dependent cell proliferation and capillary tube formation, and prevention of vasculature formation in tumor tissues. CS2164 also showed induction of G2/M cell cycle arrest and suppression of cell proliferation in tumor tissues through the inhibition of Aurora B‐mediated H3 phosphorylation. Furthermore, CS2164 demonstrated the inhibitory effect on CSF‐1R phosphorylation that led to the suppression of ligand‐stimulated monocyte‐to‐macrophage differentiation and reduced CSF‐1R(+) cells in tumor tissues. The in vivo animal efficacy studies revealed that CS2164 induced remarkable regression or complete inhibition of tumor growth at well‐tolerated oral doses in several human tumor xenograft models. Collectively, these results indicate that CS2164 is a highly selective multi‐kinase inhibitor with potent anti‐tumor activities against tumor angiogenesis, mitosis and chronic inflammation, which may provide the rationale for further clinical assessment of CS2164 as a therapeutic agent in the treatment of cancer.