We have found, by cytospectrophotometric methods, that a small number of rat liver nodules induced by an initiation-promotion regimen have an aneuploid modal DNA content. Over the past two years we have not only confirmed the initial finding, but also determined that aneuploidy is present when either choline deficiency or phenobarbital are given separately after the same initiation treatment with diethylnitrosamine. We now have preliminary evidence, which will have to be validated in future experiments, that the administration of diethylnitrosamine alone or the feeding of a choline deficient diet by itself produces aneuploidy in some enzyme altered foci. The quantitative alterations in the genome that result in aneuploidy are in fact a manifestation of the PROGRESSION stage during transformation into malignancy. Since aneuploidy results in a heterogeneous cell population, the subsequent ability of some tumors to metastasize may have been decided at the beginning of the carcinogenic process and not later, as a consequence of changes that follow overt malignancy. Cytospectrophotometry is a grudging, slow methodology. The advent of Computerized Digital Image Analysis, together with the complete automation of the system we propose in this application, should overcome most of these problems. The second phase of our investigations will be at first devoted mostly to the originally planned experiments to study the relationship between ploidy distribution, nodule persistence and hepatoma development. Treatment of these animals has already been performed in the first funding cycle. With the use of Computerized Image Analysis we will also determine whether aneuploidy is seen with either promoting treatment or with diethylnitrosamine when each is applied separately. In the last part of our studies we will examine, using the same methodology, whether aneuploidy is caused by clastogenic changes due to the administration of methyl-N- nitros-urea/phenobarbital or aflatoxin B1/phenobarbital or by agents that produce abnormal or arrested mitotic spindles, such as diethylstilbestrol. The experiments proposed will help to understand the mechanisms of PROGRESSION in the rat liver in vivo (as opposed to cells in culture) and may result in less restrictive but more veritable regulations for in vivo tests of hepatocarcinogenesis.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA035362-05
Application #
3172940
Study Section
Pathology B Study Section (PTHB)
Project Start
1985-04-01
Project End
1992-03-31
Budget Start
1990-04-01
Budget End
1991-03-31
Support Year
5
Fiscal Year
1990
Total Cost
Indirect Cost
Name
Case Western Reserve University
Department
Type
Schools of Medicine
DUNS #
077758407
City
Cleveland
State
OH
Country
United States
Zip Code
44106
McCoy, G D; DeMarco, G J; Haxhiu, L et al. (1994) Effect of acute administration of N-nitrosopyrrolidine to male Syrian golden hamsters. Cancer Lett 79:161-5
Sudilovsky, O; Hinrichsen, L I; Hei, T K et al. (1991) Genetic instability occurs sooner than expected: promotion, progression and clonality during hepatocarcinogenesis in the rat. Basic Life Sci 57:263-77
Sudilovsky, O; Hei, T K (1991) Aneuploidy and progression in promoted preneoplastic foci during chemical hepatocarcinogenesis in the rat. Cancer Lett 56:131-5
Wang, J H; Hinrichsen, L I; Whitacre, C M et al. (1990) Nuclear DNA content of altered hepatic foci in a rat liver carcinogenesis model. Cancer Res 50:7571-6
Hinrichsen, L I; Floyd, R A; Sudilovsky, O (1990) Is 8-hydroxydeoxyguanosine a mediator of carcinogenesis by a choline-devoid diet in the rat liver? Carcinogenesis 11:1879-81
Malhotra, O P; Sudilovsky, O (1987) Monoclonal antibodies to prothrombin. Thromb Res 47:501-10
Sudilovsky, O; Hei, T K (1987) Prestaining of membrane markers to identify specific areas for Feulgen cytophotometric determinations in a single section. Anal Quant Cytol Histol 9:323-7