This study will focus on promoter-independent expression of an oncofetal mRNA-transport protein with a molecular weight 65 kDa (p65) which has been functionally characterized by its ability to enhance the transport of mRNA to the exterior of isolated cell nuclei in hepatocarcinogenesis. The overall objective of this study is to elucidate the mechanisms of expression of p65 in rat liver during the course of chemically induced hepatocarcinogenesis. Specifically, (i) Rat p65 will be microsequenced and protein sequence homology searches will be carried out in order to determine if the p65 structure is unique or the same or related to that of other known proteins and whether p65 has some other functions in vivo in addition to the putative stimulation of the mRNA transport. Alternatively, the rat p65 gene will be cloned, sequenced and characterized and its regulation during rat hepatocarcinogenesis will be elucidated using a cDNA probe. (ii) Immunohistochemical techniques will be employed to identify the cellular site(s) of the p65 synthesis at early time-points following the administration of N-nitrosodiethylamine and determine whether minifoci of putative initiated hepatocytes are the main site of p65 synthesis. The p65 production and DNA synthesis will be monitored at specific times after partial hepatectomy, with and without subsequent carcinogen treatment. (iii) Using the two-stage model for hepatocarcino-genesis, the effect of the choline-deficient diet on p65 expression in oval cells and or altered hepatic foci during promotion will be investigated by means of immunohisto-chemistry. The p65 production will be correlated with the level of DNA synthesis and mitotic activity of altered hepatic foci. Cell type specificity of the p65 production in carcinogen induced preneoplastic lesions and malignant tumors will also be investigated using anti-p65 antibodies and recently developed monoclonal antibodies to different preneoplastic liver cell populations induced by chemical carcinogens in rats. (iv) The effects of withdrawal and subsequent re-administration of the choline-deficient diet on p65 expression in developing altered hepatic foci will be correlated with the persistence of reversibility. We will correlate the p65 expression in promoter-independent foci with the expression of some protooncogenes. It will also be established if the use of N- diethylnitrosamine, a genotoxic carcinogen (initiator) is prerequisite for the induction of p65 in the choline-deficiency model.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA054296-03
Application #
2095809
Study Section
Chemical Pathology Study Section (CPA)
Project Start
1991-04-15
Project End
1996-03-31
Budget Start
1993-04-01
Budget End
1996-03-31
Support Year
3
Fiscal Year
1993
Total Cost
Indirect Cost
Name
University of Texas MD Anderson Cancer Center
Department
Type
Organized Research Units
DUNS #
001910777
City
Houston
State
TX
Country
United States
Zip Code
77030
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Hanausek, M; Wang, S C; Blonski, J Z et al. (1996) Expression of an oncofetal 65-kDa phosphoprotein in lymphocytic and granulocytic leukemias. Int J Hematol 63:193-203
Hanausek, M; Sherman, U; Mirowski, M et al. (1994) Induction of a 65-kDa tumor-associated protein in altered hepatic foci of rats fed the peroxisome proliferator Wy-14,643. Prog Clin Biol Res 387:337-48
Mirowski, M; Klijanienko, J; Wang, S et al. (1994) Serological and immunohistochemical detection of a 65-kDa oncofetal protein in breast cancer. Eur J Cancer 30A:1108-13
Mirowski, M; Walaszek, Z; Sherman, U et al. (1993) Demonstration of a 65 kDa tumor-specific phosphoprotein in urine and serum of rats with N-methyl-N-nitrosourea-induced mammary adenocarcinomas. Carcinogenesis 14:1659-64
Mirowski, M; Walaszek, Z; Sherman, U et al. (1993) Comparative structural analysis of human and rat 65 kDa tumor-associated phosphoproteins. Int J Biochem 25:1865-71
Mirowski, M; Sherman, U; Hanausek, M (1992) Purification and characterization of a 65-kDa tumor-associated phosphoprotein from rat transplantable hepatocellular carcinoma 1682C cell line. Protein Expr Purif 3:196-203