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Abstract

Grant Number:	1R03MH076515-01
Project Title:	Screen:DNA-PKcs Autophosphorylation Blockers Cell(RMI)

PI Information:	Name	Email	Title
	CHEN, BENJAMIN PING-CHI.	benjamin.chen@utsouthwestern.edu

Abstract: DESCRIPTION (provided by applicant): Radiation treatment is one of the most important cancer-therapeutic approaches. Non-toxic radiosensitizers, used in conjunction with radiation therapy, would enhance the effectiveness of the radiotherapy and, at the same time, reduce the total radiation dose to prevent unwanted side effects. DNA double-strand breaks (DSBs) are the major DNA lesion induced by ionizing radiation (IR) and the dominant cause of radiation sensitivity. It is well established that lack of DSB repair can be lethal in mammalian cells. DNA-dependent protein kinase (DNA-PK) is the key component of the DNA nonhomologous end-joining (NHEJ) pathway that is the predominant pathway for DSB repair in mammalian cells. We have shown that inhibition of DNA-PK kinase activity and/or abrogation of radiation-induced autophosphorylation of DNA-PKcs (the catalytic subunit of DNA-PK) results in severe radiation sensitivity. As the autophosphorylation of DNA-PKcs is a requisite step for NHEJ mediated DSBs repair, molecules that inhibit autophosphorylation without affecting the protein levels of DNA-PK or its enzymatic activity could selectively radiosensitize cells without affecting other cellular processes; whereas molecules that inhibit the kinase activity of DNA-PK also commonly inhibit other PI-3K like protein kinases (ATM and ATR) and cause significant cellular toxicity. In this proposal, we plan to develop both lysate-based and cell-based high throughput screening (HTS) assay to identify chemicals or natural compounds that would either block the autophosphorylation of DNA-PKcs or inhibit the kinase activity of DNA-PKcs. With regard to the approaches,

Public Health Relevance:
This Public Health Relevance is not available.

Thesaurus Terms:
drug discovery /isolation, drug screening /evaluation, enzyme inhibitor, high throughput technology, inhibitor /antagonist, method development, protein kinase, radiosensitizer
DNA repair, bioassay, enzyme activity, neoplasm /cancer radiation therapy
biotechnology, tissue /cell culture

Institution:	UNIVERSITY OF TEXAS SW MED CTR/DALLAS
	DALLAS, TX 753909105
Fiscal Year:	2005
Department:	RADIATION ONCOLOGY
Project Start:	15-SEP-2005
Project End:	14-SEP-2006
ICD:	NATIONAL INSTITUTE OF MENTAL HEALTH
IRG:	ZMH1

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