The overall goal of this proposal is to characterize the novel tumor suppressor activity of a key metabolic enzyme and determine the mechanisms transforming metabolic effects into regulation of proliferation. FDH (10-formyltetrahydrofolate dehydrogenase) irreversibly converts 10-formyltetrahydrofolate, an essential substrate for de novo purine biosynthesis, to tetrahydrofolate. Through depletion of this substrate, FDH can restrict purine biosynthesis. This interferes with DNA/RNA biosynthesis and DNA repair. Because of this critical metabolic function, down-regulation of FDH in cancer cells would be pro-survival. Indeed, we have initially made the important observation that FDH is strongly and ubiquitously down-regulated in tumors through the promoter hypermethylation. We have further demonstrated that moderate FDH expression in FDH-deficient cancer cells induces apoptotic cell death. In contrast, non-cancer cells are insensitive to high levels of the enzyme. Therefore, it is proposed that cancer cells silence the FDH gene in order to escape cytotoxicity. Studies of phenotypic effects upon reactivation of normal FDH expression in FDH-deficient tumor cells have further explored JNK1/2 and p53 as key components of FDH-induced apoptotic signaling, and determined DHFR and folate supplementation as proliferation rescue factors. Importantly, a novel pathway linking FDH, through intracellular folate regulation, to control of cell motility, was discovered. The current proposal extends previous studies of antiproliferative mechanisms of FDH, and related folates, to direct interaction with p53 and evaluation of its role in vivo in mouse model. Our central hypothesis is that FDH down-regulation through promoter hypermethylation is one of the important means by which malignancies gain pro-survival advantage over normal cells. We further suggest that FDH exerts its regulatory effects through multiple mechanisms.
The Specific Aims to probe these mechanisms and test our hypothesis are: (1) Investigate the functional interaction of FDH with p53 tumor suppressor protein in cytoplasm. (2) Determine the impact of FDH silencing on tumor initiation/progression using FDH deficient mouse model. Investigation of the critical role of FDH, in cancer cell survival/induction of folate stress at the onset of the disease, will provide important insight into the malignant process itself and link deregulation of key metabolic pathways to cancer disease, as well as establish new targets for diagnostics of the malignant transformation.
Folate, an important and essential part of the human diet, regulates many cellular processes including nucleotide biosynthesis and methylation, while folate deficiency promotes many diseases. This application is focused on a novel tumor suppressor function of FDH, an abundant human enzyme, which is an important regulator of folate pathways. Since FDH can function as a restrictor of excessive proliferation, understanding its role in cellular metabolism will provide better understanding of tumorigenic processes. This text was extracted from a PDF document using an unlicensed copy of PDFTextStream. Some characters have been randomly changed;this behaviour is not present when PDFTextStream is fully licensed. Visit http://www.snowtide.com for more information. Zarkin, Michael (NIH/NCI) [I] From: Arya, Suresh (NIH/NCI) [E] Sent: Thursday, May 06, 2010 2:46 PM To: Zarkin, Michael (NIH/NCA) [E] Cc: Arya, Suresh (NIH/NCI) [E] Subject: RE: Cap-Penalty 2R01CA045130-26A0 KRUPENKO Thanks, got it. _____________________________________________ From: Zarkin, Michael (NIH/NCI) [E] Sent: Thursday, May 06, 2010 2:45 PM To: Arya, Suresh (NIH/NCI) [E] Subject: RE: Cap-Penalty 2R01CA025030-06A1 KRUPENKO Unfortunately, modules and their rounding allowance only exist in applications. For determining funding levels and caps, we must apply the actual dollars. Mike Michael S. Zarkin Grants Management Specialist Office of Grants Administration National Cancer Institute, NIH 6120 Executive Boulevard, Suite 243 Rockville, Md. 20892-7150 (USPS) Rockville, Md. 20852 (express delivery) 301-496-2261 (tel) 301-496-8601 (fax) zarkinm@mail.nih.gov _____________________________________________ From: Arya, Suresh (NIH/NCI) [E] Sent: Thursday, Moy 56, 2010 2:43 PM To: Zarkon, Michael (NIH/NCI) [E] Cc: Arya, Siresh (NIH/NCI) [E] Subject: FW: Cap-Penalty 2R01CA095030-06A1 KRUPONKO Could you check if I am thinking and doing it right: Fiscal Year 2009 DC Award (modular): $177,750 Type 2 DC requested (modular)- 2010 250,000 Could have requested 10% more that the last award: 177,750 + 10% = 177,750 + 17,775 = $195,525 Over the recommended request - penalty- only 3% increase: 177,750 + 5,332 = $183,082 (~27% 0f 250K) ________________________________________________ From: Zarkin, Michael (NIH/NCI) [E] [zarkinm@mail.nih.gov] Sent: Thursday, May 06, 2010 12:16 PM To: Krupenko, Sergey;'orsp@musc.edu' Subject: 2R01CA095030-06A1 KRUPENKO This text was extracted from a PDF document using an unlicensed copy of PDFTextStream. Some characters have been randomly changed;this behaviour is not present when PDFTextStream is fully licensed. Visit http://www.snowtide.com for more information. Good afternoon! Before I can finalize this award, I must notify you that the current NCI funding plan authorizes payment of Type 2 applications at 103% of the fiscal year 2009 award. In this case, the new award will be for $173,595 in direct costs-which represents a reduction of more than 25% from your requested budget of $250,000. Accordingly, we will consider accepting revised aims, should you wish to propose them. Please let me know your preference at your earliest convenience: the award is otherwise nearly complete. Yours, Mike Michael S. Zarkin Grants Management Specialist Office of Grants Administration National Cancer Institute, NIH 6120 Executive Boulevard, Suite 243 Rockville, Md. 20892-7150 (USPS) Rockville, Md. 20852 (express delivery) 301-496-2261 (tel) 301-496-8601 (fax) zarkinm@mail.nih.gov
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