HS-173, a novel phosphatidylinositol 3-kinase (PI3K) inhibitor, has anti-tumor activity through promoting apoptosis and inhibiting angiogenesis.

We synthesized a novel imidazopyridine analogue, a PI3Kα inhibitor HS-173 and investigated anti-cancer capacity in human cancer cells. HS-173 inhibited the PI3K signaling pathway, and showed anti-proliferative effects on cancer cells. Also, HS-173 induced cell cycle arrest at the G(2)/M phase and apoptosis. In addition, HS-173 decreased the expression HIF-1α and VEGF which play an important role in angiogenesis. This effect was confirmed by the suppression of tube formation and migration assay in vitro. Furthermore, HS-173 diminished blood vessel formation in the Matrigel plug assay in mice. Therefore, HS-173 is considered as a novel drug candidate to treat cancer patients.