New Molecular Bioassays for the Estimation of the Teratogenic Potency of Valproic Acid Derivatives in Vitro: Activation of the Peroxisomal Proliferator-Activated Receptor (PPARδ)

• Published in: Toxicology and applied pharmacology Vol. 160; no. 3; pp. 238 - 249
• Main Authors: Lampen, Alfonso, Siehler, Sandra, Ellerbeck, Ursula, Göttlicher, Martin, Nau, Heinz
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 01.11.1999; Elsevier
• Subjects: Animals; Anticonvulsants - chemistry; Anticonvulsants - toxicity; Avian Sarcoma Viruses - genetics; Biological and medical sciences; Biological Assay - methods; Cell Differentiation - drug effects; CHO cells; CHO Cells - drug effects; CHO Cells - metabolism; CHO Cells - virology; Cricetinae; differentiation; DNA Primers - chemistry; Dose-Response Relationship, Drug; Drug toxicity and drugs side effects treatment; F9 cells; Genes, Viral; In Vitro Techniques; Medical sciences; Mice; Miscellaneous (drug allergy, mutagens, teratogens...); peroxisome proliferator-activated receptors; Pharmacology. Drug treatments; PPAR; Receptors, Cytoplasmic and Nuclear - metabolism; Reverse Transcriptase Polymerase Chain Reaction; Rous sarcoma virus; Structure-Activity Relationship; Teratocarcinoma - genetics; Teratocarcinoma - metabolism; Teratocarcinoma - pathology; Teratocarcinoma - virology; teratogenicity; Teratogens - chemistry; Teratogens - toxicity; Transcription Factors - metabolism; Transfection; Tumor Cells, Cultured; valproic acid; Valproic Acid - chemistry; Valproic Acid - toxicity; differentiation; valproic acid; PPAR; CHO cells; teratogenicity; F9 cells; Toxicity; Activation; Anticonvulsant; Valproic acid; Cell differentiation; In vitro; CHO cell line; Peroxisome proliferator; Structure activity relation; Teratogen; Transcription factor; Mechanism of action; Peroxisome proliferator activated receptor; Biological receptor
• ISSN: 0041-008X; 1096-0333
• DOI: 10.1006/taap.1999.8770

Therapy with the antiepileptic drug valproic acid (2-propylpentanoic acid, VPA) during early pregnancy can cause teratogenic effects (neural tube defects) in humans and in mice. VPA and a teratogenic derivative specifically induce differentiation of F9 teratocarcinoma cells and activate PPARδ. We have now studied structure–activity relationships of 11 VPA-related compounds by quantitatively comparing their teratogenic potency with their effects in the two novel in vitro systems. Based on the induction of a Rous sarcoma virus (RSV) promoter-driven reporter gene, which is associated with the differentiation of F9 cells, a system suitable for high-throughput and quantitative screening was established. Structure–activity investigations showed that only teratogenic derivatives of VPA induced the response in F9 cells as well as activated the PPARδ-dependent reporter system in Chinese hamster ovary (CHO) cells. Increases in the length of the side chain in the VPA-related 2-alkyl-pentynoic acid generate more potent inducers in the cell-culture-based assays, which also show higher teratogenicity and embryonic lethality rates. Activation of PPARδ correlated well with the effects in the F9 cell assay and with teratogenic potency in vivo (p < 0.007). Evaluation of the effects of the presented set of compounds allows the conclusion that the in vitro systems faithfully reflect teratogenicity of VPA-related compounds. Whether the activation of PPARδ is causally related to the disruption of proper embryonic development or whether it reflects other yet unknown VPA-induced events remains to be established.