The major reason for the failure of anticancer drug therapy in most advanced solid tumors is the presence of chemotherapy-resistant tumor cells. Apoptosis is now considered to be an essential event in antitumor drug induced death. Therefore, cells with deficient apoptotic pathways may be incapable of producing an efficient apoptotic response, regardless of the agent to which they are exposed. For this reason, gene therapy using proapoptotic genes that can either trigger apoptosis in chemo-resistant cells or reconstitute the apoptotic pathway to enhance chemotherapy is a potential therapeutic strategy. The transcription factor, E2F-1, has recently been identified as a potent tumor suppressor. We and others have shown that E2F- 1 overexpression efficiently induces apoptosis in a variety of tumor types, independent of p53 status, both in vitro and in vivo. However, the mechanisms by which E2F-1 induces apoptosis remain ill defined. Mechanistically, our preliminary data implicate activation of the Fas death receptor pathway, involving ASK1, JNK, p38, and ERK MAP kinases in E2F- 1-mediated apoptosis, a novel finding. Furthermore, NFkappaB activation and downregulation of inhibitors of apoptosis (IAPs, specifically XIAP and cIAP-1) and the antiapoptotic Bcl-2 family member, Mcl-1 were seen after E2F-1- overexpression, again novel findings. Furthermore, our preliminary studies indicate that topoisomerase I and II agents, and the drug temozolomide work cooperatively with E2F-1 to induce apoptosis in colon cancer and melanoma cells in vitro and in vivo. Based on substantial preliminary data and the existing literature, we have proposed a model of the signal transduction pathways involved in E2F-1-mediated apoptosis. To evaluate this model and further dissect the molecular mechanisms of E2F-1-induced apoptosis, SK-MEL-2 melanoma and HT-29 colon cancer cells will be studied. Following adenovirus-mediated gene transfer we will analyze the role of Fas/FasL interaction, JNK, p38, and ERK activation, NFKB activation, and XIAP, cIAP-1 and Mcl-1 in E2F-1-mediated apoptosis. Investigation will also be carried out using combinations of adenovirus E2F-1 and specific chemotheraeutic agents that act cooperatively with E2F-1 (adriamycin. camptothecin, temozolomide) to evaluate the mechanisms by which E2F-1 augments the apoptotic response to chemotherapy. Finally, a novel adenoviral vector expressing a truncated E2F-1 mutant that maintains apoptotic function but lacks E2F-1 transactivation function will be constructed and tested for potential enhancement of tumor death. These studies will enhance our understanding of E2F-1-mediated cell death and facilitate the design of improved treatment strategies.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA090784-03
Application #
6797897
Study Section
Experimental Therapeutics Subcommittee 1 (ET)
Program Officer
Wolpert, Mary K
Project Start
2002-09-01
Project End
2006-08-31
Budget Start
2004-09-01
Budget End
2005-08-31
Support Year
3
Fiscal Year
2004
Total Cost
$244,388
Indirect Cost
Name
University of Louisville
Department
Surgery
Type
Schools of Medicine
DUNS #
057588857
City
Louisville
State
KY
Country
United States
Zip Code
40292
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Gomez-Gutierrez, Jorge G; Egger, Michael E; Hao, Hongying et al. (2012) Adenovirus-mediated expression of mutated forkhead human transcription like-1 suppresses tumor growth in a mouse melanoma xenograft model. Cancer Biol Ther 13:1195-204
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Gomez-Gutierrez, Jorge G; Garcia-Garcia, Aracely; Hao, Hongying et al. (2010) Adenovirus-mediated expression of truncated E2F-1 suppresses tumor growth in vitro and in vivo. Cancer 116:4420-32
Hao, Hongying; Zhou, H Sam; McMasters, Kelly M (2009) Chemosensitization of tumor cells: inactivation of nuclear factor-kappa B associated with chemosensitivity in melanoma cells after combination treatment with E2F-1 and doxorubicin. Methods Mol Biol 542:301-13
Zheng, Xinyu; Rao, Xiao-Mei; Gomez-Gutierrez, Jorge G et al. (2008) Adenovirus E1B55K region is required to enhance cyclin E expression for efficient viral DNA replication. J Virol 82:3415-27
Gomez-Gutierrez, Jorge G; Elpek, Kutlu G; Montes de Oca-Luna, Roberto et al. (2007) Vaccination with an adenoviral vector expressing calreticulin-human papillomavirus 16 E7 fusion protein eradicates E7 expressing established tumors in mice. Cancer Immunol Immunother 56:997-1007
Hao, Hongying; Dong, Yanbin; Bowling, Maria T et al. (2007) E2F-1 induces melanoma cell apoptosis via PUMA up-regulation and Bax translocation. BMC Cancer 7:24
Dong, Yan Bin; Phelps, Allison M; Yang, Hai Liang et al. (2007) Induction of apoptosis signal-regulating Kinase 1 by E2F-1 may not be essential for E2F-1-mediated apoptosis in melanoma cells. Tumour Biol 28:111-22

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