The goal of this project is to determine the sequence of cellular events that evolve during development of chemically induced murine hepatomas. In order to identify the cellular changes occurring during initiation, promotion and progression of neoplastic transformation, we have employed histochemical, immunohistochemical, radioreceptor and in situ hybridization techniques. Transplantation of hepatocytes to the anterior chamber of the rat eye is used to evaluate the stage of transformation and the proliferative capacity of hepatocytes. Results obtained include: (1) Preneoplastic liver cells were selected on the basis of their lack of affinity to tissue culture plates coated with asialofetuin; these preneoplastic cells showed a definite growth advanatage in the anterior chamber when promoted by phenobarbital. (2) Normal hepatocytes and hepatocytes treated with carcinogens survived in the anterior chamber for several months. (3) Cells derived from hyperplastic liver nodules progress into frank malignant hepatoma when transplanted to the anterior chamber of the eye. (4) Both phenobarbital, a liver specific tumor promoter, and partial hepatectomy reduced the number of liver-specific asialoglycoprotein receptors (ASGP-R) on the surface of the hepatocytes. The demonstrated lack of ASGP-R may be importance as a mechanism of tumor promotion in the liver. (5) In situ hybridization of rat albumin and alpha-fetoprotein c-DNA probes for liver m-RNA has been used to define the conditions for in situ hybridization of c-DNA probes to target mRNA.
