Fig. 1: Genetic status of CDK4-pathway nodes does not predict protein expression or durability of CDK4/6 inhibition.

A Copy number variation and mutational status were assessed across a panel of ALM and non-ALM models. B Western blot showing basal expression of cell cycle proteins across a panel of ALM and non-ALM models. Shown in the right panel is a densitometric quantification of cyclin D1 expression. C Cells were treated with increasing concentrations of palbociclib for 24 h before Western blotting. D A panel of ALM models were treated with increasing concentrations of palbociclib, E ribociclib, or (F) abemaciclib for 72 h before cell numbers were quantified using MTT. Bars show S.E. mean. G A panel of ALM cell lines were treated with palbociclib for 3–4 weeks before colonies were fixed and stained with crystal violet. Photographs are representative of three independent experiments and relative clonogenic survival quantitation is shown to the right. H WM4324 cells were treated with palbociclib (500 nM) for the time shown before EdU incorporation and imaging to assess cell proliferation. Two sample t-test was used to compare means of any two groups’ Cyclin D expression, confluency and EdU incorporation in figure B, G, and H. *p < 0.05 and n = 3 unless otherwise stated throughout panels.