Related Experiment Videos
Multistage chemical carcinogenesis in mouse skin
Current Problems in Dermatology
|January 1, 1980
Summary
Chemicals initiate skin tumors via DNA mutation, followed by promotion involving cell changes and proliferation. Inhibitors like retinoic acid and fluocinolone acetonide target specific tumor promotion steps.
Area of Science:
- Chemical carcinogenesis
- Molecular toxicology
- Dermatology
Background:
- Skin tumors in mice can be induced by a two-stage process: initiation and promotion.
- Initiation involves irreversible DNA damage, likely somatic cell mutation, by carcinogens.
- Polycyclic aromatic hydrocarbons (PAHs) initiate tumors via DNA adducts formed by their diol-epoxide metabolites.
Purpose of the Study:
- To elucidate the mechanisms of chemical carcinogenesis in mouse skin.
- To identify key steps and molecular targets in tumor initiation and promotion.
- To investigate the effects of specific inhibitors on these carcinogenic processes.
Main Methods:
- Studied chemical carcinogen-induced skin tumors in mice.
- Assessed the correlation between carcinogen mutagenicity and tumor initiation.
- Investigated the role of polycyclic aromatic hydrocarbons (PAHs) and their DNA adducts.
- Analyzed the multi-step nature of tumor promotion, including cell induction, prostaglandin/polyamine production, and cell proliferation.
- Evaluated the inhibitory effects of retinoic acid and fluocinolone acetonide.
Main Results:
- Initiation is an irreversible, likely mutagenic step, with strong correlation between carcinogenicity and mutagenicity.
- PAH carcinogenicity correlates with covalent binding to epidermal DNA, with "bay region" diol-epoxides as ultimate carcinogens.
- Tumor promotion involves induction of dark cells, increased prostaglandins/polyamines, and sustained dark cell proliferation.
- Retinoic acid inhibits prostaglandin/polyamine production (step 2 of promotion).
- Fluocinolone acetonide inhibits dark cell induction and proliferation (steps 1 and 3 of promotion).
Conclusions:
- Chemical carcinogenesis in mouse skin is a multi-step process involving distinct initiation and promotion phases.
- Specific molecular events, including DNA adduct formation and cellular changes, are critical for tumor development.
- Targeted inhibition of promotion steps offers potential strategies for chemoprevention.