Development of pharmacodynamic biomarkers for ATR inhibitors.

ABSTRACT:

Background

ATR, which signals DNA damage to S/G2 cell cycle checkpoints and for repair, is an attractive target in cancer therapy. ATR inhibitors are being developed and a pharmacodynamic assay is needed to support clinical studies.

Methods

Phosphorylation of ATR targets, Chk1 and H2AX, was evaluated in MCF7 and K562 cells, human volunteer PBMCs and whole blood by Western blot, immunofluorescence microscopy and flow cytometry after DNA damage. The effect of cell cycle phase, ATR knockdown and inhibition on these phosphorylation events was determined.

Results

Hydroxyurea, UV and 4NQO induced Chk1 and H2AX phosphorylation in MCF7 and K562 cells. UV/4NQO activation of ATR was detectable in non-cycling cells. Chk1 phosphorylation was reduced by ATR knockdown and reflects

SUBMITTER: Chen T 

PROVIDER: S-EPMC5528661 | biostudies-literature | 2015 Feb

REPOSITORIES: biostudies-literature