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[Structure-activity relationships in experimental neuro-oncology (author's transl)]
Abstract:
Hitherto more than 40 neurotropic chemical carcinogens have been detected. In part, their structure differs considerably from each other. Structure-activity relationships have not been discovered so far within this group of carcinogens. However, those carcinogens whose presumed ultimate carcinogen is represented by an ethyl or methyl cation showed a stronger prenatal neuro-oncogenic effect of ethyl compounds than the analogous methyl compounds. Contrary to this, the methyl compounds exerted a higher neurotropic activity than the corresponding ethyl compounds in adult animals (table I). These findings were now examined by means of ethyl methanesulphonate (EMS) and methyl methanesulphonate (MMS) in pre- and postnatal experiments in rats. Surprisingly, we yielded opposite results. Neurogenic tumors were produced in 9.4% of the animals by prenatal application of EMS whereas following repeated postnatal EMS injections 82.1% of the rats developed neurogenic neoplasms (tables II, III). Further investigations should clarify whether EMS and MMS represent exceptional chemical carcinogens or whether there are other couples of neurotropic carcinogens that show an activity similar to the alkyl methanesulphonates.
Insights
Ethyl methanesulfonate (EMS) and methyl methanesulfonate (MMS) show opposite neuro-oncogenic effects based on administration timing. Prenatal exposure to EMS yielded tumors in 9.4% of rats, while postnatal exposure resulted in 82.1% tumor incidence.
Area of Science:
- Neuro-oncology
- Chemical carcinogenesis
- Toxicology
Context:
- Over 40 neurotropic chemical carcinogens are known, with diverse structures and poorly understood structure-activity relationships.
- Previous observations suggested ethyl compounds had stronger prenatal neuro-oncogenic effects than methyl analogues, while methyl compounds were more active in adults.
- This study investigates ethyl methanesulfonate (EMS) and methyl methanesulfonate (MMS) to explore these differing effects.
Purpose:
- To examine the neuro-oncogenic effects of ethyl methanesulfonate (EMS) and methyl methanesulfonate (MMS) in pre- and postnatal rat models.
- To determine if the observed differences in ethyl vs. methyl compound neurotropic activity extend to alkyl methanesulfonates.
- To clarify the role of administration timing in the neuro-oncogenic potential of these specific chemical carcinogens.
Summary:
- Contrary to expectations, prenatal exposure to EMS resulted in neurogenic tumors in 9.4% of rats.
- In contrast, repeated postnatal EMS injections led to neurogenic neoplasms in 82.1% of rats, indicating a significant age-dependent effect.
- These findings challenge previous structure-activity relationship assumptions for neurotropic carcinogens and highlight the importance of administration timing.
Impact:
- Suggests that EMS and MMS may represent exceptional chemical carcinogens regarding their neuro-oncogenic activity.
- Warrants further investigation into whether other neurotropic carcinogen pairs exhibit similar activity patterns to alkyl methanesulfonates.
- Provides crucial data for understanding age-dependent susceptibility to chemical carcinogens and refining neuro-oncology research.