Biomaterial Database

Hepatocarcinogenicity of chlordane in B6C3F1 and B6D2F1 male mice: evidence for regression in B6C3F1 mice and carcinogenesis independent of ras proto-oncogene activation. 1995

D E Malarkey, and T R Devereux, and G E Dinse, and P C Mann, and R R Maronpot

Department of Microbiology, Pathology and Parasitology, College of Veterinary Medicine, North Carolina State University, Raleigh 27606, USA.

Logistic regression analysis of age-specific prevalences for neoplastic and non-neoplastic liver lesions was used to examine treatment responses for B6C3F1 and B6D2F1 male mice continuously exposed to chlordane (55 p.p.m.) and to determine whether neoplasms were dependent on continuous exposure in the B6C3F1 mice. In order to determine if ras oncogene activation plays a role in the carcinogenicity of chlordane and whether the activation is dependent on genetic background, liver tumors from chlordane-treated B6C3F1 and B6D2F1 mice were analyzed for the presence of activating mutations in the ras oncogene. The overall liver tumor prevalence at terminal killing was nearly 100% for both strains; however, the age-specific prevalence increased more rapidly in B6C3F1 mice than in B6D2F1 mice. Tumor-bearing B6C3F1 mice had an average of two or more tumors per liver than B6D2F1 mice at their respective terminal killings (5.4 versus 3.3). When chlordane exposure was discontinued for a group of B6C3F1 mice ('stop' group) at 491 days of age, overall tumor multiplicity significantly decreased by 30% from an average of 4.4 per tumor-bearing-animal at 525 days to 3.1 at terminal killing (568 days). Over the same time period the prevalence of hepatocellular carcinomas significantly decreased from 80 to 54% and adenomas from 100 to 93% by terminal killing in B6C3F1 'stop-group' mice. Chlordane induced diffuse hepatocellular centrilobular hypertrophy, frequent multinucleate hepatocytes, toxic change and hepatoproliferative lesions composed predominantly of acidophilic hepatocytes in nearly 100% of both the B6C3F1 and B6D2F1 mice. The development of histological evidence of toxicity closely paralleled the temporal development of hepatocellular neoplasia and decreased in severity when the tumor burden was maximal. No H- or K-ras mutations were detected in the chlordane-induced hepatocellular tumors in B6C3F1 mice (15 adenomas and 15 carcinomas) or B6D2F1 mice (10 adenomas and 10 carcinomas). In conclusion, chlordane induced liver tumors in both B6C3F1 and B6D2F1 male mice by mechanisms independent of ras oncogene activation and 30% of both benign and malignant liver tumors in the B6C3F1 mice regressed after exposure was discontinued.

UI	MeSH Term	Description	Entries
D006984	Hypertrophy	General increase in bulk of a part or organ due to CELL ENLARGEMENT and accumulation of FLUIDS AND SECRETIONS, not due to tumor formation, nor to an increase in the number of cells (HYPERPLASIA).	Hypertrophies
D007306	Insecticides	Pesticides designed to control insects that are harmful to man. The insects may be directly harmful, as those acting as disease vectors, or indirectly harmful, as destroyers of crops, food products, or textile fabrics.	Insecticide
D008099	Liver	A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.	Livers
D008114	Liver Neoplasms, Experimental	Experimentally induced tumors of the LIVER.	Hepatoma, Experimental,Hepatoma, Morris,Hepatoma, Novikoff,Experimental Hepatoma,Experimental Hepatomas,Experimental Liver Neoplasms,Hepatomas, Experimental,Neoplasms, Experimental Liver,Experimental Liver Neoplasm,Liver Neoplasm, Experimental,Morris Hepatoma,Novikoff Hepatoma
D008297	Male		Males
D008815	Mice, Inbred Strains	Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations, or by parent x offspring matings carried out with certain restrictions. All animals within an inbred strain trace back to a common ancestor in the twentieth generation.	Inbred Mouse Strains,Inbred Strain of Mice,Inbred Strain of Mouse,Inbred Strains of Mice,Mouse, Inbred Strain,Inbred Mouse Strain,Mouse Inbred Strain,Mouse Inbred Strains,Mouse Strain, Inbred,Mouse Strains, Inbred,Strain, Inbred Mouse,Strains, Inbred Mouse
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
D011905	Genes, ras	Family of retrovirus-associated DNA sequences (ras) originally isolated from Harvey (H-ras, Ha-ras, rasH) and Kirsten (K-ras, Ki-ras, rasK) murine sarcoma viruses. Ras genes are widely conserved among animal species and sequences corresponding to both H-ras and K-ras genes have been detected in human, avian, murine, and non-vertebrate genomes. The closely related N-ras gene has been detected in human neuroblastoma and sarcoma cell lines. All genes of the family have a similar exon-intron structure and each encodes a p21 protein.	Ha-ras Genes,Ki-ras Genes,N-ras Genes,c-Ha-ras Genes,c-Ki-ras Genes,c-N-ras Genes,ras Genes,v-Ha-ras Genes,v-Ki-ras Genes,H-ras Genes,H-ras Oncogenes,Ha-ras Oncogenes,K-ras Genes,K-ras Oncogenes,Ki-ras Oncogenes,N-ras Oncogenes,c-H-ras Genes,c-H-ras Proto-Oncogenes,c-Ha-ras Proto-Oncogenes,c-K-ras Genes,c-K-ras Proto-Oncogenes,c-Ki-ras Proto-Oncogenes,c-N-ras Proto-Oncogenes,ras Oncogene,v-H-ras Genes,v-H-ras Oncogenes,v-Ha-ras Oncogenes,v-K-ras Genes,v-K-ras Oncogenes,v-Ki-ras Oncogenes,Gene, Ha-ras,Gene, Ki-ras,Gene, v-Ha-ras,Gene, v-Ki-ras,Genes, Ha-ras,Genes, Ki-ras,Genes, N-ras,Genes, v-Ha-ras,Genes, v-Ki-ras,H ras Genes,H ras Oncogenes,H-ras Gene,H-ras Oncogene,Ha ras Genes,Ha ras Oncogenes,Ha-ras Gene,Ha-ras Oncogene,K ras Genes,K ras Oncogenes,K-ras Gene,K-ras Oncogene,Ki ras Genes,Ki ras Oncogenes,Ki-ras Gene,Ki-ras Oncogene,N ras Genes,N ras Oncogenes,N-ras Gene,N-ras Oncogene,c H ras Genes,c H ras Proto Oncogenes,c Ha ras Genes,c Ha ras Proto Oncogenes,c K ras Genes,c K ras Proto Oncogenes,c Ki ras Genes,c Ki ras Proto Oncogenes,c N ras Genes,c N ras Proto Oncogenes,c-H-ras Gene,c-H-ras Proto-Oncogene,c-Ha-ras Gene,c-Ha-ras Proto-Oncogene,c-K-ras Gene,c-K-ras Proto-Oncogene,c-Ki-ras Gene,c-Ki-ras Proto-Oncogene,c-N-ras Gene,c-N-ras Proto-Oncogene,ras Gene,ras Oncogenes,v H ras Genes,v H ras Oncogenes,v Ha ras Genes,v Ha ras Oncogenes,v K ras Genes,v K ras Oncogenes,v Ki ras Genes,v Ki ras Oncogenes,v-H-ras Gene,v-H-ras Oncogene,v-Ha-ras Gene,v-Ha-ras Oncogene,v-K-ras Gene,v-K-ras Oncogene,v-Ki-ras Gene,v-Ki-ras Oncogene
D002706	Chlordan	A highly poisonous organochlorine insecticide. The EPA has cancelled registrations of pesticides containing this compound with the exception of its use through subsurface ground insertion for termite control and the dipping of roots or tops of non-food plants. (From Merck Index, 11th ed)	Chlordane,gamma-Chlordane,gamma Chlordane
D005786	Gene Expression Regulation	Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control (induction or repression) of gene action at the level of transcription or translation.	Gene Action Regulation,Regulation of Gene Expression,Expression Regulation, Gene,Regulation, Gene Action,Regulation, Gene Expression