Background:

PI-103 is a dual inhibitor of PI3K/Akt and mTOR with IC50 value of 0.002 μM , 0.003μM, 0.003μM, 0.015μM, 0.030μM for P110α, P110β, P110γ, P110 and mTOR, respectively [1].

PI3K/AKT/mTOR pathway is an intracellular signaling pathway and plays an important role in regulating cell cycle. It has been shown that PI3K/AKT/MTOR pathway is directly related to cellular quiescence, proliferation, cancer, and longevity. And many studies have shown that activation of the PI3K/Akt signaling pathway is correlated with poor prognosis in a variety of cancers which demonstrated that inhibition of the pathway may be regarded as a promising therapy [2, 3].

PI-103 is a selective PI3K/Akt and mTORC1 inhibitor. When tested with leukemic cell lines (MOLM14, OCI-AML3 and MV4-11) with activation of PI3K/Akt, mTORC1 and ERK/MAPK signaling pathways, PI-103 blocked cells proliferation via inhibiting PI3K/Akt and mTORC1 activity in a concentration of 1μM [4]. In HCC cell line--Huh7 cells, treated PI-103 alone or combined with sorafenib inhibited cells proliferation in a dose-dependent manner through inhibition of PI3K/Akt and mTORC1 pathways [5]. When tested with U87MG glioblastoma cells, PI-103 treatment in 30 nM/L showed significant inhibition of PI3K/Akt and mTORC1 phosphorylation [1]. In neuroblastoma cell lines SK-N-BE (2), IMR-32 with amplified MYCN, PI-103 inhibited cell growth in a time- and concentration-dependent manner via inhibiting PI3K/Akt and mTORC1 activity [3].

In SK-N-BE (2) with MYCN-mutant xenografted nude mice model, treated PI-103 intraperitoneally (10 mg/kg) markedly reduced the tumor volume index and tumor weight via inhibiting PI3K/ mTOR pathways [1].

参考文献:
[1].  Raynaud, F.I., et al., Biological properties of potent inhibitors of class I phosphatidylinositide 3-kinases: from PI-103 through PI-540, PI-620 to the oral agent GDC-0941. Mol Cancer Ther, 2009. 8(7): p. 1725-38.
[2].  Hambright, H.G., et al., Inhibition of PI3K/AKT/mTOR axis disrupts oxidative stress-mediated survival of melanoma cells. Oncotarget, 2015.
[3].  Segerstrom, L., et al., Effects of small molecule inhibitors of PI3K/Akt/mTOR signaling on neuroblastoma growth in vitro and in vivo. Int J Cancer, 2011. 129(12): p. 2958-65.
[4].  Park, S., et al., PI-103, a dual inhibitor of Class IA phosphatidylinositide 3-kinase and mTOR, has antileukemic activity in AML. Leukemia, 2008. 22(9): p. 1698-706.
[5].  Gedaly, R., et al., PI-103 and sorafenib inhibit hepatocellular carcinoma cell proliferation by blocking Ras/Raf/MAPK and PI3K/AKT/mTOR pathways. Anticancer Res, 2010. 30(12): p. 4951-8.