This revised application seeks 4 years' support for studies of molecular mechanisms by which UV radiation induces skin cancer in mice. The cellular and molecular processes that occur during the initial carcinogen-cell interaction and the onset of tumor growth are largely unknown. Previous studies have demonstrated mutations in the p53 tumor suppressor gene, and to a certain extent, in ras oncogenes in both human and UV-induced mouse skin cancers. It is, however, not known whether these mutations arise early or late during UV skin carcinogenesis. The objectives of the proposal are to identify the temporal changes, at the cellular and molecular level, that occur during UV skin carcinogenesis, and to determine whether these alterations result in deregulated apoptotic cell death in the epidermis. The hypothesis is that alterations in the p53 tumor suppressor gene are early events and that dysregulation of apoptotic cell death and apoptosis regulatory genes contribute to the development and progression of UV-induced skin cancer.
The specific aims are: (1) To determine whether the UV-induced ras and p53 mutations are early or late events during skin carcinogenesis; (2) to determine whether dysregulation of apoptosis contributes to the development of UV-induced skin cancer; (3) to determine whether specific genetic alterations present in UV-induced mouse skin tumor cells influence their susceptibility to interferon-gamma- or tumor necrosis factor-induced apoptosis. To these ends, in Aim 1, UV-irradiated mouse skin will be analyzed at progressive time points during skin carcinogenesis for ras and p53 mutations by allele-specific polymerase chain reaction followed by single-strand conformation polymorphism analysis and nucleotide sequencing.
In Aim 2 the induction of sunburn (apoptotic) cells in UV-irradiated mouse skin during skin carcinogenesis will be measured in situ by the TUNEL method, and expression of apoptosis regulatory genes such as p53, Bcl-2, and Bax, will be determined by western blotting using specific antibodies.
In Aim 3 the relationship between specific genetic alterations present in UV-induced mouse skin cancers and susceptibility to interferon-gamma- or tumor necrosis factor-induced apoptosis will be investigated by MTT dye uptake, DNA fragmentation, and chromatin condensation assays.
| Benjamin, Cara L; Melnikova, Vladislava O; Ananthaswamy, Honnavara N (2008) P53 protein and pathogenesis of melanoma and nonmelanoma skin cancer. Adv Exp Med Biol 624:265-82 |
| Benjamin, Cara L; Ullrich, Stephen E; Kripke, Margaret L et al. (2008) p53 tumor suppressor gene: a critical molecular target for UV induction and prevention of skin cancer. Photochem Photobiol 84:55-62 |
| Benjamin, Cara L; Ananthaswamy, Honnavara N (2008) Oncogenic potential of BRAF versus RAS. Cancer Lett 261:137-46 |
| Pacifico, A; Goldberg, L H; Peris, K et al. (2008) Loss of CDKN2A and p14ARF expression occurs frequently in human nonmelanoma skin cancers. Br J Dermatol 158:291-7 |
| Benjamin, Cara L; Ananthaswamy, Honnavara N (2007) p53 and the pathogenesis of skin cancer. Toxicol Appl Pharmacol 224:241-8 |
| Benjamin, Cara L; Melnikova, Vladislava O; Ananthaswamy, Honnavara N (2007) Models and mechanisms in malignant melanoma. Mol Carcinog 46:671-8 |
| Kim, Seungwon; Yazici, Yasemin D; Calzada, Gabriel et al. (2007) Sorafenib inhibits the angiogenesis and growth of orthotopic anaplastic thyroid carcinoma xenografts in nude mice. Mol Cancer Ther 6:1785-92 |
| Huang, Chun-Ming; Ananthaswamy, Honnavara N; Barnes, Stephen et al. (2006) Mass spectrometric proteomics profiles of in vivo tumor secretomes: capillary ultrafiltration sampling of regressive tumor masses. Proteomics 6:6107-16 |
| Wolf, Peter; Nghiem, Dat X; Walterscheid, Jeffrey P et al. (2006) Platelet-activating factor is crucial in psoralen and ultraviolet A-induced immune suppression, inflammation, and apoptosis. Am J Pathol 169:795-805 |
| Melnikova, Vladislava O; Ananthaswamy, Honnavara N (2005) Cellular and molecular events leading to the development of skin cancer. Mutat Res 571:91-106 |
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