Background:

Poziotinib (HM781-36B) is an irreversible pan-HER inhibitor with IC50 values of 3.2, 5.3 and 23.5 nM for HER1, HER2 and HER4, respectively [1].

Epidermal growth factor receptors (EGFR/HER1, HER2/ErbB2, HER3/ErbB3, HER4/ErbB4) are receptor tyrosine kinases and play important roles in cell proliferation and differentiation. The EGFR family is a major target of anticancer drugs [1].

Poziotinib is an irreversible pan-HER inhibitor. In HER2 amplified SNU216 and N87 gastric cancer cells, HM781-36B inhibited cell growth with IC50 values of 4 and 1 nM, respectively. Also, HM781-36B potently inhibited the phosphorylation of HER family and downstream proteins such as STAT3, AKT and ERK, and induced G1 arrest and apoptosis. HM781-36B dose-dependently increased the amount of cleaved form of effector caspases (caspase-3 and caspase-7) and PARP, reduced antiapoptotic proteins BCL-2 and MCL-1, and induced proapoptotic protein BIM [1]. In HER2-amplified breast cancer cells, HM781-36B inhibited cell growth with IC50 values of 1, 1.2 and 9.5 nM for SK-BR-3, BT474, and MDA-MB-453 cells, respectively [2].

In nude mouse bearing N87 human gastric cancer xenograft model, HM781-36B significantly inhibited tumor growth and exhibited a synergistic effect when administered with chemotherapeutic agents [1].

参考文献:
[1].  Nam HJ, Kim HP, Yoon YK, et al. Antitumor activity of HM781-36B, an irreversible Pan-HER inhibitor, alone or in combination with cytotoxic chemotherapeutic agents in gastric cancer. Cancer Lett, 2011, 302(2): 155-165.
[2].  Kim HJ, Kim HP, Yoon YK, et al. Antitumor activity of HM781-36B, a pan-HER tyrosine kinase inhibitor, in HER2-amplified breast cancer cells. Anticancer Drugs, 2012, 23(3): 288-297.