The central goal of this application is to develop a rational mechanistic basis for employing agents that disrupt the mitogen activated protein kinase (MAPK) signal transduction pathway in order to potentiate the anti-tumor activity of ionizing radiation. This strategy is based upon recent evidence indicating that specific inhibitors of the MAPK pathway interact synergistically with radiation to initiate the apoptotic protease cascade. Our underlying hypothesis is that inhibition of MAPK, an enzyme implicated in G2/M progression, leads to a potentiation of radiation-mediated cell death. We postulate that this phenomenon stems from, or is profoundly influenced by, perturbations in cell cycle regulation, a diminished threshold for tolerating mitochondria) dysfunction, and a reduced ability to survive radiation-induced DNA damage. We have shown in human carcinoma cells that are autocrine regulated via an ErbB 1 and TGFalpha interaction, survive irradiation in a MAPK- dependent fashion. Radiation causes activation of the MAPK pathway and blunting of MAPK activation enhanced the proportion of cells found in G2/M phase 24h after irradiation, which was associated with increased apoptosis. In this proposal we will examine how the MAPK signaling pathway is responsible for cell cycle control, caspase regulation and survival, with measurements of apoptosis and cell cycle regulatory protein expression in carcinoma cells.
In Aims 1 and 2 we will test the hypothesis that MAPK inhibition enhances radiation-induced cell killing by potentiating the activation of caspases 8, 9 and 3.
In Aim 3 we will test the hypothesis that reduced MAPK activity modifies the radiation / ATM / cdc 2 interaction, altering cell cycle progression leading to enhanced apoptosis. We propose that MAPK signaling is an essential survival factor in the response of the cell to DNA damage. Collectively, these studies will determine the molecular mechanisms by which inhibition of MAPK enhances apoptosis and radio-sensitivity.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA088906-02
Application #
6522724
Study Section
Radiation Study Section (RAD)
Program Officer
Stone, Helen B
Project Start
2001-08-01
Project End
2005-07-31
Budget Start
2002-08-01
Budget End
2003-07-31
Support Year
2
Fiscal Year
2002
Total Cost
$195,750
Indirect Cost
Name
Virginia Commonwealth University
Department
Radiation-Diagnostic/Oncology
Type
Schools of Medicine
DUNS #
City
Richmond
State
VA
Country
United States
Zip Code
23298
Martin, Aditi Pandya; Miller, Anna; Emad, Luni et al. (2008) Lapatinib resistance in HCT116 cells is mediated by elevated MCL-1 expression and decreased BAK activation and not by ERBB receptor kinase mutation. Mol Pharmacol 74:807-22
Dai, Yun; Chen, Shuang; Pei, Xin-Yan et al. (2008) Interruption of the Ras/MEK/ERK signaling cascade enhances Chk1 inhibitor-induced DNA damage in vitro and in vivo in human multiple myeloma cells. Blood 112:2439-49
Dai, Yun; Chen, Shuang; Kramer, Lora B et al. (2008) Interactions between bortezomib and romidepsin and belinostat in chronic lymphocytic leukemia cells. Clin Cancer Res 14:549-58
Lebedeva, Irina V; Emdad, Luni; Su, Zao-Zhong et al. (2007) mda-7/IL-24, novel anticancer cytokine: focus on bystander antitumor, radiosensitization and antiangiogenic properties and overview of the phase I clinical experience (Review). Int J Oncol 31:985-1007
Mitchell, Clint; Park, Margaret A; Zhang, Guo et al. (2007) 17-Allylamino-17-demethoxygeldanamycin enhances the lethality of deoxycholic acid in primary rodent hepatocytes and established cell lines. Mol Cancer Ther 6:618-32
Mitchell, Clint; Park, Maragret A; Zhang, Guo et al. (2007) Extrinsic pathway- and cathepsin-dependent induction of mitochondrial dysfunction are essential for synergistic flavopiridol and vorinostat lethality in breast cancer cells. Mol Cancer Ther 6:3101-12
Dent, Paul; Hylemon, Philip B; Grant, Steven et al. (2007) Approaches for monitoring signal transduction changes in normal and cancer cells. Methods Mol Biol 383:259-76
Grant, Steven; Dent, Paul (2007) Simultaneous interruption of signal transduction and cell cycle regulatory pathways: implications for new approaches to the treatment of childhood leukemias. Curr Drug Targets 8:751-9
Dai, Yun; Khanna, Payal; Chen, Shuang et al. (2007) Statins synergistically potentiate 7-hydroxystaurosporine (UCN-01) lethality in human leukemia and myeloma cells by disrupting Ras farnesylation and activation. Blood 109:4415-23
Pei, Xin-Yan; Dai, Yun; Tenorio, Sarah et al. (2007) MEK1/2 inhibitors potentiate UCN-01 lethality in human multiple myeloma cells through a Bim-dependent mechanism. Blood 110:2092-101

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