Augmented expression of cytokines in mouse epidermal tumor cells and its possible involvement in the induction of hematopoietic alterations

Interaction between the immune system and tongue squamous cell carcinoma induced by 4-nitroquinoline N-oxide in mice

Squamous cell carcinoma of the oral cavity (SCC) accounts for 3% of cancers in the western world and 40% of cancers in India. The overall 5-year survival rate is only 50%. Most of the lesions appear intra-orally on the tongue. Results from a previous study demonstrated a significant increase in T and B-lymphocytes under the transformed epithelium when examining human lesions of hyperkeratosis, dysplasia and carcinoma of the tongue. In order to investigate the interaction between the host immunity and SCC, carcinogen induced SCC of the tongue was studied in mice. The water-soluble carcinogen, 4 nitroquinoline N-oxide (4NQO), was applied to BALB/c mice tongues and produced tongue SCC after a long incubation period of several months. Immunologic properties were examined systemically in the spleens and locally, at the tumor site. Examination of spleen lymphocytes from 4NQO induced mice revealed enlargement of the spleens and a significant decrease in the CD3, CD4, CD8 and CD19 cells. In the tongues, expression of TGF-beta, TNF-alpha, GM-CSF, and IL-1 beta mRNA were detected. TNF-alpha protein was detected in the affected tongues using immunoassays. mRNA expression of TNF-alpha was detected in the cancerous epithelium when extracted from the connective tissue. CD11b and CD3 cells were detected in the connective tissue under the developing carcinoma. CD11b positive cells were more prominent. The infiltrate was very scattered and not prominent as the infiltrate in the human tongue tissues. These results indicate that the growing tumor affected the immune response around the tumor and systemically. Most of the cytokines, which appeared in the affected tongues, originated from the tumor surroundings, but TNF-alpha was found also in the tumor. The interaction between the tumor and immune response components is important for diagnosis and treatment purposes.

Spontaneous and chemically induced proliferative lesions in Tg.AC transgenic and p53-heterozygous mice

Recently, the use of selected genetically altered mouse models in the detection of carcinogens after short-term chemical exposures has been evaluated. Studies of several chemicals conducted by the National Toxicology Program in Tg.AC transgenic and heterozygous p53-deficient mice have been completed recently and represent a major contribution to this effort, as well as the largest accumulation to date of toxicologic pathology data in these 2 lines of mice. The purpose of this report is to describe the proliferative target organ effects observed in this set of studies, as well as to present the tumor profile in the control groups of this data set. These findings provide a comprehensive toxicologic assessment of these 2 genetically altered mouse strains, which are of emerging importance in toxicologic pathology.

Induction of PA2.26, a cell-surface antigen expressed by active fibroblasts, in mouse epidermal keratinocytes during carcinogenesis

The monoclonal antibody PA2.26, produced against mouse epidermal keratinocytes transformed with 7,12-dimethylbenz[a]anthracene (DMBA), recognizes a 43- to 47-kDa cell-surface protein that was absent from non-tumorigenic epidermal keratinocytes but present in transformed epidermal cell lines as well as cultured normal fibroblasts. In vivo, the antigen was absent from normal epidermis but induced in basal-like epidermal keratinocytes and dermal fibroblasts during tissue regeneration after wounding and treatment with the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA). The PA2.26 protein was also expressed in basal-like cells of differentiated papillomas and carcinomas generated in mice treated with DMBA and TPA. In addition, the antigen was abundantly synthesized by stromal cells of the tumors. These results suggest that PA2.26 antigen is involved in reactive processes during skin remodeling and carcinogenesis.