Characterization of the novel and specific PI3Kα inhibitor NVP-BYL719 and development of the patient stratification strategy for clinical trials.

Somatic PIK3CA mutations are frequently found in solid tumors, raising the hypothesis that selective inhibition of PI3Kα may have robust efficacy in PIK3CA-mutant cancers while sparing patients the side-effects associated with broader inhibition of the class I phosphoinositide 3-kinase (PI3K) family. Here, we report the biologic properties of the 2-aminothiazole derivative NVP-BYL719, a selective inhibitor of PI3Kα and its most common oncogenic mutant forms. The compound selectivity combined with excellent drug-like properties translates to dose- and time-dependent inhibition of PI3Kα signaling in vivo, resulting in robust therapeutic efficacy and tolerability in PIK3CA-dependent tumors.

Rescue screens with secreted proteins reveal compensatory potential of receptor tyrosine kinases in driving cancer growth.

The overall power of kinase inhibitors is substantially overshadowed by the acquisition of drug resistance. To address this issue, we systematically assessed the potential of secreted proteins to induce resistance to kinase inhibitors. To this end, we developed a high-throughput platform for screening a cDNA library encoding 3,432 secreted proteins in cellular assays.

Caveolae: biochemical analysis.

Caveolae appear in a multitude of processes encompassing growth regulation and trafficking. We demonstrate the abundant presence of ESA/reggie-1/flotillin-2, ATP synthase beta subunit and annexin V in endothelial caveolae by immunopurification of caveolae from vascular endothelial membrane. Five proteins are abundant in a caveolin-1 protein complex, analyzed by sucrose gradient velocity sedimentation following octyl-beta-D-glucopyranoside extraction.

Involvement of alpha5beta1 integrins in interleukin 8 production induced by oral viridans streptococcal protein I/IIf in cultured endothelial cells.

Using human endothelial cells, we define a mechanism that accounts for the induction of interleukin 8 (IL-8) by protein I/IIf, an adhesin from Streptococcus mutans serotype f. We report that protein I/IIf interactions with endothelial cells increased the tyrosine phosphorylation of three cellular components with relative mass of 145,000, 125,000 and 70,000 in endothelial cells. These proteins were identified as phospholipase Cgamma (PLCy), focal adhesion kinase (FAK) and paxillin after immunoprecipitation with monoclonal antibodies (mAbs) and immunoblotting with antiphosphotyrosine mAbs.

TNF-alpha release by monocytic THP-1 cells through cross-linking of the extended V-region of the oral streptococcal protein I/II.

We tested the hypothesis of a conserved activation mode of monocytic THP-1 cells by proteins I/II expressed by several species of oral streptococci through the specific role of the extended V-region. We studied the binding and modulating activities of six proteins I/II purified from strains representing four different species of oral streptococci, and of expression products of polymerase chain reaction-amplified sequences encoding corresponding extended V-regions. We found that the different proteins I/II bound to THP-1 cells in a sugar-dependent mode involving the extended V-region.