Cell experiment:

MTT and CCK-8 assays are performed to determine the general sensitivities of cells to the tested drugs. The human colon carcinoma S1 cell line and ABCG2-overexpressing subline S1-M1-80 are treated with PF-4989216 (0.1, 1 and 10 μM). The human breast carcinoma MCF-7 and ABCG2-overexpressing sublines MCF7-FLV1000 and MCF7-AdVp3000 are treated with PF-4989216 (0.1, 1, 10 and 100 μM).The parental HEK293 and ABCG2-tranfected R482-HEK293 cells are treated with PF-4989216 (0.01, 0.1, 1 and 10 μM). For the reversal of cytotoxicity assays, PF-4989216 or Ko143 or Lapatinib at a nontoxic concentration is added into the cytotoxicity assay, and the extent of reversal is then calculated[2].

Animal experiment:

Mice[1]For animal studies, 6-8 week old nu/nu athymic female mice are used. Tumors are established by injecting 2×106 cells suspended 1:1 (v/v) with reconstituted basement membrane. For tumor growth inhibition studies, mice with established tumors of ~150 mm3 are randomized. PF-4989216 (Compound 10) is dosed orally (25, 50, 100 and 200 mg/kg) in a mouse PI3K driven NCI-H1975 xenograft tumor model. Tumor dimensions are measured with vernier calipers, and tumor volumes are calculated. Tumor growth inhibition percentage (TGI %) is calculated.

Description:

IC50: 2 nM, 142 nM, 65 nM, 1 nM, and 110 nM for p110α, p110β, p110γ, p110δ, and VPS34, respectively.

The constitutive activation of phosphoinositide 3-kinase (PI3K) occurs frequently in many human tumors through either gene mutation in the p110a catalytic subunit of PI3K or functional loss of tumor suppressor PTEN. Patients with small-cell lung cancer have very poor prognosis and survival rates such that an effective targeted therapy is in strong demand for these patients. PF-4989216 is a selective oral PI3K inhibitor.

In vitro: PF-4989216 inhibited PI3K downstream signaling and led to apoptosis induction, and inhibition in cell viability, transformation, and xenograft tumor growth in small-cell lung cancer (SCLC) harboring PIK3CA mutation. In SCLC with PTEN loss, PF-4989216 also inhibited PI3K signaling but did not induce BCL2-interacting mediator-mediated apoptosis nor was there any effect on cell viability or transformation [1].

In vivo: The mouse in vivo results indicate a good correlation between in vitro and in vivo efficacy, and further confirm that PF-4989216 is an effective drug candidate capable of inducing antitumor activity in mice bearing human SCLC tumors with PIK3CA mutation [1].

Clinical trial: Up to now, PF-4989216 is still in the preclinical development stage.

Reference:
[1] Walls M, Baxi SM, Mehta PP, Liu KK, Zhu J, Estrella H, Li C, Zientek M, Zong Q, Smeal T, Yin MJ.  Targeting small cell lung cancer harboring PIK3CA mutation with a selective oral PI3K inhibitor PF-4989216. Clin Cancer Res. 2014 Feb 1;20(3):631-43.