The presence of a significant percentage of hypoxic cells (10-25%) in animal and human tumors can influence the outcome of both radiotherapy and chemotherapy. Although the hypoxic fraction in animal tumors often increases with size, no tumor characteristic such as histology, size volume doubling time, site of growth, or degree of differentiation has been found to predict either the presence of hypoxic cells or the hypoxic fraction in human tumors. Thus, a rapid, accurate method for detecting and quantitating hypoxic cells in human tumors could make a substantial impact on the treatment of cancer by allowing both radiotherapy and chemotherapy to be individualize based on he characteristics of each patient's tumor. There are two classes of radiation-induced DNA damage whose formation exhibits an oxygen dependency similar to that for radiation-induced cell killing. The O2 dependency for formation of DNA-protein crosslinks (DPCs) is virtually the mirror image of the O2 dependency for radiation-induced cell kill. The formation of radiation-induced DNA strand breaks (SBs) has an O2 dependency virtually identical to the O2 dependency for radiation- induced cell kill. Both phenomena lead to a retardation in the removal of DNA from the filter during alkaline elution. After a given volume of elution, the amount DNA remaining on the filter is linearly related to the percentage of hypoxic cells in the irradiated tissue. The goals of the proposed research are to: 1) determine if an alkaline elution assay for SBs and DCPCs can reliably measure the hypoxic fraction of mouse and human tumors, 2) provide the data to properly select the radiation dose and sampling procedures for animal and human trials using this assays, and 3) characterize the chemical nature and location of the DPCs measured by this DNA assay as a function of the O2 concentration, metabolic state, proliferative state and time between radiation exposures. Three mouse tumors (RIF, SCCVII, KHT) and 3 human colon tumors (clone A, HCT-15, WiDR) grown as xenografts in nude mice will be used to achieve these objectives. The chemical nature of the DPCs located near the nuclear matrix or in the chromatin will be determined using GC/MSD techniques. If, 1) induction of SBs and DPCs is minimally influenced by biological and physiological factors other than the O2 concentration near the chromatin, and 2) the assay reliably predicts the hypoxic fraction of experimental mouse and human tumors, studies will be started in the clinic to test its usefulness in predicting the radiation responded of head and neck tumors or cervical carcinoma, and in the lab to validate noninvasive techniques for detecting and quantitating hypoxic cells in tumors and normal tissue.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
2R01CA045156-06A2
Application #
2091759
Study Section
Radiation Study Section (RAD)
Project Start
1987-07-01
Project End
1996-11-30
Budget Start
1994-01-05
Budget End
1994-11-30
Support Year
6
Fiscal Year
1994
Total Cost
Indirect Cost
Name
Wake Forest University Health Sciences
Department
Radiation-Diagnostic/Oncology
Type
Schools of Medicine
DUNS #
041418799
City
Winston-Salem
State
NC
Country
United States
Zip Code
27106
Kalia, V K; Al-Nabulsi, I; Wallen, C A et al. (2000) Radiation-induced DNA damage in tumors and normal tissues. VI. Estimation of the hypoxic fraction of experimental tumors. Radiat Res 153:548-56
Xu, L; Tay, C H; Huber, B T et al. (2000) Cloning of an infectious milk-borne mouse mammary tumor virus (MMTV) DNA from a mammary tumor that developed in an endogenous MMTV-free wild mouse. Virology 273:325-32
Al-Nabulsi, I; Wheeler, K T (1999) Radiation-induced DNA damage in tumors and normal tissues: V. Influence of pH and nutrient depletion on the formation of DNA-protein crosslinks in irradiated partially and fully hypoxic tumor cells. Radiat Res 151:188-94
Kalandarishvili, F; Wheeler, K T (1999) Accumulation of DNA damage in pre- and posthepatectomized liver of aged rats. Mech Ageing Dev 110:25-35
Mach, R H; Smith, C R; al-Nabulsi, I et al. (1997) Sigma 2 receptors as potential biomarkers of proliferation in breast cancer. Cancer Res 57:156-61
Al-Nabulsi, I; Wheeler, K T (1997) Temperature dependence of radiation-induced DNA-protein crosslinks formed under hypoxic conditions. Radiat Res 148:568-74
Miyagi, Y; Zhang, H; Wheeler, K T (1997) Radiation-induced DNA damage in tumors and normal tissues: IV. Influence of proliferation status and cell type on the formation of oxygen-dependent DNA damage in cultured cells. Radiat Res 148:29-34
Zhang, H; Wheeler, K T (1996) Influence of topoisomerase II on the formation of oxygen-dependent radiation-induced DNA damage. Br J Cancer Suppl 27:S196-9
Swarts, S G; Smith, G S; Miao, L et al. (1996) Effects of formic acid hydrolysis on the quantitative analysis of radiation-induced DNA base damage products assayed by gas chromatography/mass spectrometry. Radiat Environ Biophys 35:41-53
Zhang, H; Koch, C J; Wallen, C A et al. (1995) Radiation-induced DNA damage in tumors and normal tissues. III. Oxygen dependence of the formation of strand breaks and DNA-protein crosslinks. Radiat Res 142:163-8

Showing the most recent 10 out of 18 publications