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Improved ATM Kinase Inhibitor KU-60019 Radiosensitizes Glioma Cells, Compromises Insulin, AKT and ERK Prosurvival Signaling, and Inhibits Migration and Invasion

Sarah E Golding, Elizabeth Rosenberg, Nicholas Valerie, Isa Hussaini, Mark Frigerio, Xiaoling F Cockcroft, Wei Yee Chong, Marc Hummersone, Laurent Rigoreau, Keith A Menear, Mark J O'Connor, Lawrence F Povirk, etc.

Mol Cancer Ther. 2009 Oct;8(10):2894-902.

PMID: 19808981

Abstract:

Ataxia telangiectasia (A-T) mutated (ATM) is critical for cell cycle checkpoints and DNA repair. Thus, specific small molecule inhibitors targeting ATM could perhaps be developed into efficient radiosensitizers. Recently, a specific inhibitor of the ATM kinase, KU-55933, was shown to radiosensitize human cancer cells. Herein, we report on an improved analogue of KU-55933 (KU-60019) with K(i) and IC(50) values half of those of KU-55933. KU-60019 is 10-fold more effective than KU-55933 at blocking radiation-induced phosphorylation of key ATM targets in human glioma cells. As expected, KU-60019 is a highly effective radiosensitizer of human glioma cells. A-T fibroblasts were not radiosensitized by KU-60019, strongly suggesting that the ATM kinase is specifically targeted. Furthermore, KU-60019 reduced basal S473 AKT phosphorylation, suggesting that the ATM kinase might regulate a protein phosphatase acting on AKT. In line with this finding, the effect of KU-60019 on AKT phosphorylation was countered by low levels of okadaic acid, a phosphatase inhibitor, and A-T cells were impaired in S473 AKT phosphorylation in response to radiation and insulin and unresponsive to KU-60019. We also show that KU-60019 inhibits glioma cell migration and invasion in vitro, suggesting that glioma growth and motility might be controlled by ATM via AKT. Inhibitors of MEK and AKT did not further radiosensitize cells treated with KU-60019, supporting the idea that KU-60019 interferes with prosurvival signaling separate from its radiosensitizing properties. Altogether, KU-60019 inhibits the DNA damage response, reduces AKT phosphorylation and prosurvival signaling, inhibits migration and invasion, and effectively radiosensitizes human glioma cells.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
AP925701491 KU-60019 KU-60019 925701-49-1 Price
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