Autophagy (Greek, 'self-eating') is an evolutionarily conserved homeostatic process by which cytoplasmic components are sequestered into double-membraned vesicles (autophagosome) and delivered to lysosomes for degradation and recycling. This process has been increasingly recognized as essential for cell survival, differentiation, and development, and is often misregulated in human diseases, including cancer. While it has been speculated that autophagy may both benefit and hinder tumor development/progression, recent data indicates that autophagy principally serves as a tumor suppressor pathway. Yet, despite its importance, the mechanisms by which autophagy functions in tumor suppression remain largely undetermined. The proposed study is directed toward investigating how autophagy contributes to tumor suppression and how its defects contribute to malignancy, with a specific focus on a novel autophagic UVRAG gene that is monoallelically mutated at high frequencies in human cancers. Our preliminary studies have UIKO findings, we hypothesize that UVRAG is a novel autophagic tumor suppressor, which cooperates with Beclin1 and the HOPS complex to activate autophagy and inhibit tumor development. Genetic, biochemical and cell biological studies will primarily focus on defining in mechanistic detail the dual roles of UVRAG in autophagosome formation (Aim 1) and autophagosome maturation (Aim 2), and their functional significance in UVRAG tumor suppressor activity (Aim 3). Insights gained from this study will not only illuminate new views on the autophagy regulatory network, but also suggest new strategy for cancer control.

Public Health Relevance

Many studies have shed light on the role of autophagy in cancer biology, making it an attractive therapeutic target, but it remains unclear and controversial whether autophagy suppresses tumorigenesis or favors tumor growth. The challenge of the proposed study is to investigate the molecular basis of autophagy in tumor development with a specific focus on a novel autophagic tumor suppressor UVRAG, which may ultimately contribute to the establishment of new therapeutic strategy for cancer control.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA140964-04
Application #
8294825
Study Section
Cancer Molecular Pathobiology Study Section (CAMP)
Program Officer
Salnikow, Konstantin
Project Start
2009-09-21
Project End
2014-07-31
Budget Start
2012-08-01
Budget End
2013-07-31
Support Year
4
Fiscal Year
2012
Total Cost
$293,460
Indirect Cost
$112,312
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
Pirooz, Sara Dolatshahi; He, Shanshan; Zhang, Tian et al. (2014) UVRAG is required for virus entry through combinatorial interaction with the class C-Vps complex and SNAREs. Proc Natl Acad Sci U S A 111:2716-21
He, Shanshan; Ni, Duojiao; Ma, Binyun et al. (2013) PtdIns(3)P-bound UVRAG coordinates Golgi-ER retrograde and Atg9 transport by differential interactions with the ER tether and the beclinýý1 complex. Nat Cell Biol 15:1206-19
Trisciuoglio, Daniela; De Luca, Teresa; Desideri, Marianna et al. (2013) Removal of the BH4 domain from Bcl-2 protein triggers an autophagic process that impairs tumor growth. Neoplasia 15:315-27
Yang, Chul-Su; Lee, Jong-Soo; Rodgers, Mary et al. (2012) Autophagy protein Rubicon mediates phagocytic NADPH oxidase activation in response to microbial infection or TLR stimulation. Cell Host Microbe 11:264-76
Zhao, Zhen; Oh, Soohwan; Li, Dapeng et al. (2012) A dual role for UVRAG in maintaining chromosomal stability independent of autophagy. Dev Cell 22:1001-16
Liang, Chengyu (2012) Viral FLIPping autophagy for longevity. Cell Host Microbe 11:101-3
Lee, Gina; Liang, Chengyu; Park, Gihyun et al. (2011) UVRAG is required for organ rotation by regulating Notch endocytosis in Drosophila. Dev Biol 356:588-97
Oh, S; Xiaofei, E; Ni, D et al. (2011) Downregulation of autophagy by Bcl-2 promotes MCF7 breast cancer cell growth independent of its inhibition of apoptosis. Cell Death Differ 18:452-64
Ku, Bonsu; Liang, Chengyu; Jung, Jae U et al. (2011) Evidence that inhibition of BAX activation by BCL-2 involves its tight and preferential interaction with the BH3 domain of BAX. Cell Res 21:627-41
Liang, C (2010) Negative regulation of autophagy. Cell Death Differ 17:1807-15

Showing the most recent 10 out of 12 publications