Chemoproteomics reveals novel protein and lipid kinase targets of clinical CDK4/6 inhibitors in lung cancer

By N. Sumi, B. Kuenzi, Claire E. Knezevic, L. L. Rix, U. Rix. 2015

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Several selective CDK4/6 inhibitors are in clinical trials for non-small cell lung cancer (NSCLC). Palbociclib (PD0332991) is included in the phase II/III Lung-MAP trial for squamous cell lung carcinoma (LUSQ). We noted differential cellular activity between palbociclib and the structurally related ribociclib (LEE011) in LUSQ cells. Applying an unbiased mass spectrometry-based chemoproteomics approach in H157 cells and primary tumor samples, we here report distinct proteome-wide target profiles of these two drug candidates in LUSQ, which encompass novel protein and, for palbociclib only, lipid kinases. In addition to CDK4 and 6, we observed CDK9 as a potent target of both drugs. Palbociclib interacted with several kinases not targeted by ribociclib, such as casein kinase 2 and PIK3R4, which regulate autophagy. Furthermore, palbociclib engaged several lipid kinases, most notably PIK3CD and PIP4K2A/B/C. Accordingly, we observed modulation of autophagy and inhibition of AKT signaling by palbociclib, but not ribociclib.

Subfields: Oncology, Pulmonary and Respiratory Medicine