In vivo inhibition of PI3Kδ and BTK leads to TMD8 tumor regression.

<p>(A) Response of randomized TMD8 xenograft tumors (n = 13 per group) treated with PI3Kδ inhibitor (GS-649443, 1 or 5 mg/kg, BID), BTK inhibitor (ONO/GS-4059, 3 or 10 mg/kg, BID) or combination. Tumor volumes are expressed as mean ± SEM with P<0.05, P <0.0001 as compared to vehicle animals. (B) Tumors from vehicle, GS-649443 (5 mg/kg), ONO/GS-4059 (10 mg/kg) or GS-649443 + ONO/GS-4059 (5 mg/kg + 10 mg/kg) were collected 2 hours post morning dose on day 3 of dosing, ground and lysed. Protein expression was analyzed using Simple Western; T = tumor. (C) Average of same tumors (from (B)) for each treatment group (n = 3 for vehicle, GS-649443 and ONO/GS-4059 groups; n = 2 for combination); proteins were quantitated by AUC, p-BTK Y223 was normalized to total BTK protein, p-S6RP S235/236 and c-MYC were normalized to actin, and p-AKT S473 was normalized to total AKT, mean ± SD. Asterisk indicates that the AUC combination result is 0. (D) p-S6RP S235/236 and c-MYC expression detected by IHC in tumors from vehicle, GS-649443 (5 mg/kg), ONO/GS-4059 (10 mg/kg) or GS-649443 + ONO/GS-4059 (5 mg/kg + 10 mg/kg) treatment groups. Images were taken at 20X magnification.