Loana Musso1, Stefania Mazzini2, Anna Rossini3, Lorenzo Castagnoli4, Leonardo Scaglioni1, Roberto Artali5, Massimo Di Nicola3, Franco Zunino3, Sabrina Dallavalle1. 1. Department of Food, Environmental and Nutritional Sciences, Division of Chemistry and Molecular Biology, Università degli Studi di Milano, via Celoria 2, I-20133 Milano, Italy. 2. Department of Food, Environmental and Nutritional Sciences, Division of Chemistry and Molecular Biology, Università degli Studi di Milano, via Celoria 2, I-20133 Milano, Italy. Electronic address: stefania.mazzini@unimi.it. 3. Fondazione IRCCS, Istituto Nazionale dei Tumori, via Venezian 1, 20133 Milano, Italy. 4. Molecular Targeting Unit, Department of Applied Research and Technological Development, Fondazione IRCCS Istituto Nazionale Tumori, via Venezian 1, 20133 Milano, Italy. 5. Scientia Advice, di Roberto Artali, 20832 Desio, MB, Italy.
Abstract
BACKGROUND: Pyridoquinazolinecarboxamides have been reported as RNA polymerase I inhibitors and represent a novel class of potential antitumor agents. BMH-21, was reported to intercalate with GC-rich rDNA, resulting in nucleolar stress as a primary mechanism of cytotoxicity. METHODS: The interaction of BMH-21 and analogues with DNA G-quadruplex structures was studied by NMR and molecular modelling. The cellular response was investigated in a panel of human tumor cell lines and protein expression was examined by Western Blot analysis. RESULTS AND CONCLUSIONS: We explored the ability of BMH-21 and its analogue 2 to bind to G-quadruplex present in the c-MYC promoter, by NMR and molecular modelling studies. We provide evidence that both compounds are not typical DNA intercalators but are effective binders of the tested G-quadruplex. The interaction with c-MYC G-quadruplex was reflected in down-regulation of c-Myc expression in human tumor cells. The inhibitory effect was almost complete in lymphoma cells SUDHL4 characterized by overexpression of c-Myc protein. This downregulation reflected an early and persistent modulation of cMyc mRNA. Given the relevance of c-MYC in regulation of ribosome biogenesis, it is conceivable that the inhibition of c-MYC contributes to the perturbation of nuclear functions and RNA polymerase I activity. Similar experiments with CX-5461, another RNA polymerase I transcription inhibitor, indicate the same behaviour in G-quadruplex stabilization. GENERAL SIGNIFICANCE: Our results support the hypothesis that BMH-21 and analogue compounds share the same mechanism, i.e. G-quadruplex binding as a primary event of a cascade leading to inhibition of RNA polymerase I and apoptosis.
BACKGROUND:Pyridoquinazolinecarboxamides have been reported as RNA polymerase I inhibitors and represent a novel class of potential antitumor agents. BMH-21, was reported to intercalate with GC-rich rDNA, resulting in nucleolar stress as a primary mechanism of cytotoxicity. METHODS: The interaction of BMH-21 and analogues with DNA G-quadruplex structures was studied by NMR and molecular modelling. The cellular response was investigated in a panel of humantumor cell lines and protein expression was examined by Western Blot analysis. RESULTS AND CONCLUSIONS: We explored the ability of BMH-21 and its analogue 2 to bind to G-quadruplex present in the c-MYC promoter, by NMR and molecular modelling studies. We provide evidence that both compounds are not typical DNA intercalators but are effective binders of the tested G-quadruplex. The interaction with c-MYC G-quadruplex was reflected in down-regulation of c-Myc expression in humantumor cells. The inhibitory effect was almost complete in lymphoma cells SUDHL4 characterized by overexpression of c-Myc protein. This downregulation reflected an early and persistent modulation of cMyc mRNA. Given the relevance of c-MYC in regulation of ribosome biogenesis, it is conceivable that the inhibition of c-MYC contributes to the perturbation of nuclear functions and RNA polymerase I activity. Similar experiments with CX-5461, another RNA polymerase I transcription inhibitor, indicate the same behaviour in G-quadruplex stabilization. GENERAL SIGNIFICANCE: Our results support the hypothesis that BMH-21 and analogue compounds share the same mechanism, i.e. G-quadruplex binding as a primary event of a cascade leading to inhibition of RNA polymerase I and apoptosis.
Authors: Matilde Ortiz-Gonzalez; Ignacio Pérez-Victoria; Inmaculada Ramirez-Macias; Nuria de Pedro; Angel Linde-Rodriguez; Víctor González-Menéndez; Victoria Sanchez-Martin; Jesús Martín; Ana Soriano-Lerma; Olga Genilloud; Virginia Perez-Carrasco; Francisca Vicente; José Maceira; Carlos A Rodrígues-Poveda; José María Navarro-Marí; Fernando Reyes; Miguel Soriano; Jose A Garcia-Salcedo Journal: Int J Mol Sci Date: 2022-05-29 Impact factor: 6.208
Authors: Marta Recagni; Martina Tassinari; Filippo Doria; Graziella Cimino-Reale; Nadia Zaffaroni; Mauro Freccero; Marco Folini; Sara N Richter Journal: Cells Date: 2019-10-18 Impact factor: 6.600