Measuring nucleotide excision repair in human populations

Information

  • Research Project
  • 10202603
  • ApplicationId
    10202603
  • Core Project Number
    U01ES029603
  • Full Project Number
    5U01ES029603-04
  • Serial Number
    029603
  • FOA Number
    RFA-ES-17-006
  • Sub Project Id
  • Project Start Date
    9/21/2018 - 5 years ago
  • Project End Date
    6/30/2022 - a year ago
  • Program Officer Name
    HEACOCK, MICHELLE
  • Budget Start Date
    7/1/2021 - 2 years ago
  • Budget End Date
    6/30/2022 - a year ago
  • Fiscal Year
    2021
  • Support Year
    04
  • Suffix
  • Award Notice Date
    9/17/2021 - 2 years ago
Organizations

Measuring nucleotide excision repair in human populations

PROJECT SUMMARY Nucleotide excision repair (NER) is a DNA repair mechanism that recognizes and removes bulky, helix-distorting lesions from the nuclear genome. Key substrates for NER are lesions induced by ultraviolet (UV) radiation upon environmental exposure to sunlight and a subset of oxidative DNA lesions produced endogenously. This is dramatically illustrated by patients with xeroderma pigmentosum (XP), a disease caused by inherited defects in NER. XP patients have a 10,000-fold increased risk of skin cancer and early onset neurodegeneration. XP is heterogeneous, ranging from mild to profoundly debilitating. XP severity is proportional to the extent to which NER is disrupted. This suggests that subtle defects in NER, due to, for example, polymorphisms in NER genes, might modestly but significantly impact one?s risk of skin cancer. Since skin cancer affects 20% of Americans and is preventable (by avoiding environmental exposure to UV), identifying those at risk could have a tremendous impact on the health of Americans and healthcare costs. The greatest barrier to identifying those at risk is the lack of an assay to measure NER that is rapid, inexpensive and applicable to samples safely and easily collected from patients. NER occurs in a series of steps involving the recognition of a site of DNA damage, unwinding the DNA locally, excision of a single-stranded oligonucleotide containing the lesion, and templated DNA synthesis to fill the residual gap. NER is the only way that UV-induced photolesions are removed from the genome in human cells. Therefore, NER is measured by the detection and quantification of UV-induced DNA synthesis outside of the S-phase of the cell cycle, or unscheduled DNA synthesis (UDS). Historically, UDS measurement required the use of radioactively-labeled nucleosides and/or specialized equipment. We developed a method to measure NER that employs the thymidine analog 5-ethynyl-2'-deoxyuridine and Click-iT chemistry for fluorescent detection of UDS by flow cytometry. This can be applied to peripheral blood cells for rapid measurement of NER requiring minimally invasive sample collection. UDS in XP patients ranges from <10% to 50%. Nothing is known about the health implications of having a UDS between 50-100%, or how to define 100% NER capacity. This project aims to correct these gaps in knowledge through optimization of our functional assay and proof-of- concept pilot human studies. The assay will be applied to existing cohorts of patients seen at the University of Miami Skin Cancer Clinics, the NIH Undiagnosed Diseases Program or enrolled in the University of Maryland Amish Longevity Study, to interrogate associations between NER capacity and high risk of skin cancer, early onset neurodegeneration, and within family pedigrees, respectively. This project will yield an NER assay applicable to larger population studies aimed at testing associations between NER capacity, environmental exposures and disease risk, and begin to define ?normal? NER capacity. The assay could have a significant impact on how risk of squamous cell or basal cell carcinoma of the skin, melanoma, lung or head and neck cancer, neurodegeneration, and resistance to cancer chemotherapy is identified and managed.

IC Name
NATIONAL INSTITUTE OF ENVIRONMENTAL HEALTH SCIENCES
  • Activity
    U01
  • Administering IC
    ES
  • Application Type
    5
  • Direct Cost Amount
    331352
  • Indirect Cost Amount
    94418
  • Total Cost
    425770
  • Sub Project Total Cost
  • ARRA Funded
    False
  • CFDA Code
    113
  • Ed Inst. Type
    SCHOOLS OF MEDICINE
  • Funding ICs
    NIEHS:425770\
  • Funding Mechanism
    Non-SBIR/STTR RPGs
  • Study Section
    ZES1
  • Study Section Name
    Special Emphasis Panel
  • Organization Name
    UNIVERSITY OF MINNESOTA
  • Organization Department
    BIOCHEMISTRY
  • Organization DUNS
    555917996
  • Organization City
    MINNEAPOLIS
  • Organization State
    MN
  • Organization Country
    UNITED STATES
  • Organization Zip Code
    554552070
  • Organization District
    UNITED STATES