Effect of Tryptophan-Derived AhR Ligands, Kynurenine, Kynurenic Acid and FICZ, on Proliferation, Cell Cycle Regulation and Cell Death of Melanoma Cells-In Vitro Studies

• Published in: International journal of molecular sciences Vol. 21; no. 21; p. 7946
• Main Authors: Walczak, Katarzyna, Langner, Ewa, Makuch-Kocka, Anna, Szelest, Monika, Szalast, Karolina, Marciniak, Sebastian, Plech, Tomasz
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 26.10.2020; MDPI
• Subjects: AhR; Apoptosis; Basic Helix-Loop-Helix Transcription Factors - metabolism; Biological activity; Brain cancer; Cancer; Cancer therapies; Carbazole; Carbazoles; Carbazoles - pharmacology; Cell cycle; Cell Cycle - drug effects; Cell death; Cell growth; Cell Line, Tumor; Cell proliferation; Cell Proliferation - drug effects; Cell Survival - drug effects; Cyclin D1; Cyclin D1 - metabolism; Cyclin-dependent kinase 4; Cyclin-Dependent Kinase 4 - metabolism; Cyclin-dependent kinases; Deoxyribonucleic acid; DNA; DNA biosynthesis; Drug therapy; FICZ; Food products; Gene expression; Gene Expression Regulation, Neoplastic - drug effects; Homeostasis; Humans; Inflammation; Kinases; Kynurenic acid; Kynurenic Acid - pharmacology; kynurenine; Kynurenine - pharmacology; Ligands; Medical prognosis; Melanocytes; Melanocytes - drug effects; Melanocytes - metabolism; Melanoma; Melanoma - drug therapy; Melanoma - metabolism; Metabolites; Metastasis; Necrosis; Phosphorylation; Phosphorylation - drug effects; Physiological effects; Physiology; Proteins; Receptors, Aryl Hydrocarbon - metabolism; Retina; Retinoblastoma; Retinoblastoma protein; Retinoblastoma Protein - metabolism; Skin cancer; Toxicity; Toxicity testing; Tryptophan; Tumor suppressor genes; cell death; proliferation; melanoma; AhR; FICZ; kynurenine; kynurenic acid; tryptophan
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms21217946

Tryptophan metabolites: kynurenine (KYN), kynurenic acid (KYNA) and 6-formylindolo[3,2-b]carbazole (FICZ) are considered aryl hydrocarbon receptor (AhR) ligands. AhR is mainly expressed in barrier tissues, including skin, and is involved in various physiological and pathological processes in skin. We studied the effect of KYN, KYNA and FICZ on melanocyte and melanoma A375 and RPMI7951 cell toxicity, proliferation and cell death. KYN and FICZ inhibited DNA synthesis in both melanoma cell lines, but RPMI7951 cells were more resistant to pharmacological treatment. Tested compounds were toxic to melanoma cells but not to normal human adult melanocytes. Changes in the protein level of cyclin D1, CDK4 and retinoblastoma tumor suppressor protein (Rb) phosphorylation revealed different mechanisms of action of individual AhR ligands. Importantly, all tryptophan metabolites induced necrosis, but only KYNA and FICZ promoted apoptosis in melanoma A375 cells. This effect was not observed in RPMI7951 cells. KYN, KYNA and FICZ in higher concentrations inhibited the protein level of AhR but did not affect the gene expression. To conclude, despite belonging to the group of AhR ligands, KYN, KYNA and FICZ exerted different effects on proliferation, toxicity and induction of cell death in melanoma cells in vitro.