Patients with malignant diseases often have associated chromosomal abnormalities, but the factors which initiate or foster these alterations are poorly understood. The goal of this project is to investigate the possibility that folate deficiency, which is relatively common in this patient population, may play an important role in the development or progression of these diseases by promoting chromosomal aberrations including breaks, gaps, despiralization and increased sister chromatid exchanges (SCE). The first specific aim of this proposal is to characterize the chromosomal alterations induced by nutritional folate deficiency and their modulation by metabolites. Chinese hamster ovary cells and murine B16 melanoma cells will be grown in folate replete medium, folate deficient medium, or the latter medium supplemented with thymidine, hypoxanthine, or both nucleotides. The extent of folate deficiency will be evaluated by bioassay, the deoxyuridine (dU) suppression test, morphology and flow cytometry. Chromosomal alterations will be assessed with 5 assays: cytogenetics or flow cytometry for gain, loss or unequal exchange of DNA; detection of DNA strand breaks by alkaline filter elution and nick translation analysis; and mutation induction at specific loci (hprt and diphtheria toxin resistance). Our second specific aim is to measure the effects of folate deficiency on the mutagenicity of chemotherapeutic agents. Nutrient lack and drug effects might combine synergistically to contribute to the development of second malignancies in cancer patients. Cells will be incubated in control or folate deficient medium containing selected chemotherapeutic drugs. The effects of the drugs in control and deficient medium will be compared using the assays listed above, to look for additive or synergistic effects. The third specific aim is to determine the effect of folate status on the frequency of chemotherapy induced chromosomal alterations in patients with breast cancer. The incidence of chromosomal changes before and after chemotherapy will be determined and correlated with patient folate status as evaluated by a nutritional questionnaire, morphology, and blood folate levels. The frequency of chromosomal alterations will be assessed by karyotypic analysis, measurement of SCE, and quantification of somatic mutants at the hprt locus in lymphocytes. These studies will provide information about the incidence of folate deficiency, the degree of chromosomal instability, and the extent of synergy between folate deficiency and chemotherapeutic drugs in causing chromosomal damage.

National Institute of Health (NIH)
National Cancer Institute (NCI)
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Experimental Therapeutics Subcommittee 1 (ET)
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University of Vermont & St Agric College
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Branda, Richard F; Chen, Zhuan; Brooks, Elice M et al. (2002) Diet modulates the toxicity of cancer chemotherapy in rats. J Lab Clin Med 140:358-68
Branda, Richard F; Brooks, Elice M; Chen, Zhuan et al. (2002) Dietary modulation of mitochondrial DNA deletions and copy number after chemotherapy in rats. Mutat Res 501:29-36
Branda, Richard F; Brooks, Elice M; Chen, Zhuan et al. (2002) Nucleic acid deletions and copy number in rats. Comp Med 52:359-62
Brooks, E M; Branda, R F; Nicklas, J A et al. (2001) Molecular description of three macro-deletions and an Alu-Alu recombination-mediated duplication in the HPRT gene in four patients with Lesch-Nyhan disease. Mutat Res 476:43-54
Branda, R F; O'Neill, J P; Brooks, E M et al. (2001) The effect of folate deficiency on the cytotoxic and mutagenic responses to ethyl methanesulfonate in human lymphoblastoid cell lines that differ in p53 status. Mutat Res 473:51-71
Branda, R F; Lafayette, A R; O'Neill, J P et al. (1999) The effect of folate deficiency on the hprt mutational spectrum in Chinese hamster ovary cells treated with monofunctional alkylating agents. Mutat Res 427:79-87
Branda, R F; Nigels, E; Lafayette, A R et al. (1998) Nutritional folate status influences the efficacy and toxicity of chemotherapy in rats. Blood 92:2471-6
Branda, R F; Hacker, M; Lafayette, A et al. (1998) Nutritional folate deficiency augments the in vivo mutagenic and lymphocytotoxic activities of alkylating agents. Environ Mol Mutagen 32:33-8
Branda, R F; Lafayette, A R; O'Neill, J P et al. (1997) Effect of folate deficiency on mutations at the hprt locus in Chinese hamster ovary cells exposed to monofunctional alkylating agents. Cancer Res 57:2586-8
Branda, R F; Moore, A L; Hong, R et al. (1996) B-cell proliferation and differentiation in common variable immunodeficiency patients produced by an antisense oligomer to the rev gene of HIV-1. Clin Immunol Immunopathol 79:115-21

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