Studies in this laboratory have shown qualitative and quantitative alterations in several different immunofunctional cell types following topical application of phorbol diesters at tumor- promoting doses. Evidence for a role of such alterations in the promotion process was thereby provided, and indicated in which stageof the latter individual changes were most important. We havedemonstrated in this way that overall promoter-induced spleen cell proliferation was predominantly a consequence of inflammation, and may be relevant only in the later stages of promotion. On the other hand promoter-induced proliferation of GMCFU progenitor cells was apparently not, and was inhibited by inhibitors of promotion with inhibitory activity toward specific pathways of arachidonic acid metabolism. These findings strongly indicated a role for GM-CFU cells in promotion, but also a need todetermine underlying mechanisms. These include whether the increase proliferation was due to i) systemic promoter effects of viarelease of soluble Interleukin 3 or Colony-Stimulating Factor fromskin cells and ii) due to increased traffic from the marrow rather than proliferation in situ. Afurther finding in this laboratory was a reduction in number of Thy1+epidermal cells following topical promoter application, together with a morphological change in these and Ia+ Langerhans cellsTo further investigate the responses of these cells to promoting agents, the following parameters will be measured: i) Cell densities in epidermal sheets. ii) Cellfunctions following purification by sorting: Interleukin 1production and ability to induce contact hypersensitivity CH) for Langerhans cells, and ability to down-regulate CH forThy-1+ cells. The role of observed alterations in the above parameters in the tumor promotion process will be assessed using: i) Agents with different relative tumor-promoting and inflammatory activities. ii) Agents which inhibit promotion and inflammation to different degrees. iii) Brief and prolonged exposures to the above agents and modifiers, comparing resultant inflammatory and immunomodulatory responses. Inflammatory/promoting agents will be used with inflammatory activity which persists to different degrees. Additional studies in initiated animals will also enable alterations in immune cells to be temporally related to tumor appearance.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA034446-06
Application #
3172138
Study Section
Chemical Pathology Study Section (CPA)
Project Start
1984-07-15
Project End
1991-06-30
Budget Start
1989-07-01
Budget End
1991-06-30
Support Year
6
Fiscal Year
1989
Total Cost
Indirect Cost
Name
University of Cincinnati
Department
Type
Schools of Medicine
DUNS #
City
Cincinnati
State
OH
Country
United States
Zip Code
45221
Sherman, J H; Baxter, C S; Albert, R E (1992) Stimulation of TGF-beta 1 mRNA concentration in mouse skin treated with benzo[a]pyrene. Carcinogenesis 13:83-6
Smith Jr, J S; Wey, H E; Leikauf, G D et al. (1992) JB6 murine epidermal cell lines sensitive and resistant to 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced transformation exhibit differential arachidonic acid metabolism in response to TPA and the calcium ionophore A23187. Carcinogenesis 13:189-92
Smith Jr, J S; Wey, H E; Leikauf, G D et al. (1992) Carba-prostacyclin inhibits 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced transformation in sensitive murine epidermal JB6 cells. Carcinogenesis 13:1859-62
Baxter, C S; Andringa, A; Chalfin, K et al. (1991) Effect of tumor-promoting agents on density and morphometric parameters of mouse epidermal Langerhans and Thy-1+ cells. Carcinogenesis 12:1017-21
Baxter, C S; Andringa, A; Chalfin, K et al. (1989) Comparative histomorphometric changes in SENCAR mouse epidermis in response to multiple treatments with complete and stage-specific tumor promoting agents. Carcinogenesis 10:1855-61
Baxter, C S; Lawrence, A T (1987) Specific inhibition of phorbol diester-induced granulocyte-macrophage progenitor cell (GM-CFU) differentiation by lipoxygenase inhibitors. Cancer Lett 37:251-6
Carson, D L; Baxter, C S (1986) Decreased sulfation of cellular chondroitin sulfate in response to activators of protein kinase C. Biochem Biophys Res Commun 135:909-14
Wey, H E; Baxter, C S (1986) Phorbol diester synergistically stimulates agonist-induced lipoxygenase product formation in murine macrophages. Biochem Biophys Res Commun 140:861-7