Due to the unacceptable toxicity and ineffectiveness of currently available cancer chemotherapy and radiation, the search for new molecular targets is in high gear. While initially identified as a promoter of the autophagy pathway, UVRAG (UV irradiation-resistance associated gene) has now emerged in our recent studies as a bona fide guardian of the genome. Specifically, we have discovered that this protein mediates the repair of damaged DNA by targeting DNA-PK and patrols centrosome stability by targeting CEP63 in a manner independent of its role in autophagy signaling. We propose that UVRAG is a novel regulator of chromosomal stability, supporting a direct causal role for UVRAG inactivation in cancer development. To the best of our knowledge, these studies represent the first description of an autophagy-related factor directly functioning in centrosome regulation and DNA repair to maintain genome integrity. Thus, the proposed research will expand on this knowledge to comprehensively assess the molecular mechanisms by which UVRAG interacts with DNA-PK to activate DNA repair upon double-strand breaks (DSBs) (Aim 1) and targets CEP63 to prevent centrosome amplification (Aim 2), thereby maintaining both structural and numeric chromosomal integrity of cells. Furthermore, to determine the in vivo contribution and specific roles of chromosomal instability and autophagy in UVRAG-associated tumor suppression (Aim 3), we will develop a drug-inducible transgenic murine model, which faithfully recapitulates an oncogenic lesion of UVRAG found in human cancers.
These aims will be addressed using multidisciplinary innovative approaches that integrate state-of-the art genetic, biochemistry, quantitative live-cell imaging, and physiological assays in cells and in mice with targeted mutations in genes that are related to UVRAG and required for the regulation of genomic stability and autophagy. Results gained from this study will undoubtedly illuminate new views on UVRAG as an autophagic tumor suppressor and a protector of the genome, reveal functional interactions between UVRAG, autophagy, and genomic instability, and also hold promise for the development of novel therapeutics for cancer.

Public Health Relevance

Chromosomal instability (CIN) is a conspicuous feature of many tumors, which drives cancer progression and is also associated with poor prognosis. However, the molecular mechanisms leading to CIN are still poorly understood. This project aims to investigate how chromosome stability is controlled by an autophagy-related molecular factor, UVRAG, through non-autophagic novel mechanisms and its significance in tumor suppression in vivo, thereby providing the molecular basis for the development of novel therapeutics for cancer.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA140964-10
Application #
9616240
Study Section
Cancer Etiology Study Section (CE)
Program Officer
Witkin, Keren L
Project Start
2009-09-21
Project End
2019-12-31
Budget Start
2019-01-01
Budget End
2019-12-31
Support Year
10
Fiscal Year
2019
Total Cost
Indirect Cost
Name
University of Southern California
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
072933393
City
Los Angeles
State
CA
Country
United States
Zip Code
90089
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