Fig. 1

Alpelisib inhibits growth and PI3K signalling in HNSCC cells. a Immunoblot of PI3K and MAPK pathway members Akt, ERK1/2 and P90RSK following treatment with 5 μM alpelisib for 36 h. Densitometric quantification of each protein relative to α-tubulin is shown below each band. b Flow cytometric analysis of Cal33 and 93-VU-147T cells treated with alpelisib (5 μM) for 24 h (3 replicates per line) before BrdU incorporation and labeling with propidium iodide. Approximately 10,000 events were counted per test (5000 events are shown in each figure). Proportion of cells in each cell cycle phase is shown, + standard deviation. * represents p < 0.05, ** represents p < 0.01, *** represents p < 0.001, ns = not significant, unpaired Student’s t-test. c Immunoblot for PARP cleavage in Cal33 cells treated with alpelisib (5 μM) for 24 h, or staurosporine (2 μM) for 3 h, as a positive control. Densitometric quantification of each protein relative to α-tubulin is shown below each band