RESUMO
BACKGROUND: Angiogenesis is thought to be important in tumorigenesis and tumor progress. Vascular endothelial growth factor (VEGF) is a pluripotent cytokine and angiogenic growth factor that plays crucial roles in embryonic development and tumor progression. In many types of cancer, VEGF is overexpressed and is generally associated with tumor progression and survival rate. The polypurine/polypyrimidine sequence located upstream of the promoter region in the human VEGF gene can form specific parallel G-quadruplex structures, raising the possibility for transcriptional control of VEGF through G-quadruplex ligands. METHODS: PCR stop assay, circular dichroism (CD) spectra, RNA extraction and RT-PCR, enzyme-linked immunosorbent assay (ELISA), luciferase Assays, cell scrape test, xCELLigence real-time cell analysis (RTCA), and chick embryo chorioallantoic membrane (CAM) assay. RESULTS AND CONCLUSIONS: We found that quindoline derivatives can interact with the G-rich DNA sequences of the VEGF promoter to stabilize this G-quadruplex and suppress the transcription and expression of the VEGF protein. We also demonstrated that these derivatives exhibit potential anti-angiogenic activity in chick embryos and antitumor activity, including the inhibition of cell proliferation and migration. GENERAL SIGNIFICANCE: Our new findings have significances not only for understanding the mechanism of the G-quadruplex ligands mediating the VEGF transcription inhibition, but also for exploring a new anti-tumor strategy to blocking the transcription of VEGF to inhibit the angiogenesis in cancer cells.
Assuntos
Alcaloides , Ilhas de CpG , Indóis , Neoplasias/tratamento farmacológico , Neovascularização Patológica/tratamento farmacológico , Regiões Promotoras Genéticas , Quinolinas , Transcrição Gênica/efeitos dos fármacos , Fator A de Crescimento do Endotélio Vascular/biossíntese , Alcaloides/química , Alcaloides/farmacocinética , Alcaloides/farmacologia , Animais , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Movimento Celular/genética , Proliferação de Células/efeitos dos fármacos , Embrião de Galinha , Dicroísmo Circular , Humanos , Indóis/química , Indóis/farmacocinética , Indóis/farmacologia , Ligantes , Neoplasias/genética , Neoplasias/metabolismo , Neoplasias/patologia , Neovascularização Patológica/genética , Neovascularização Patológica/metabolismo , Neovascularização Patológica/patologia , Quinolinas/química , Quinolinas/farmacocinética , Quinolinas/farmacologia , Transcrição Gênica/genética , Fator A de Crescimento do Endotélio Vascular/genéticaRESUMO
The c-MYC oncogene is overactivated during Burkitt's lymphoma pathogenesis. Targeting c-MYC to inhibit its transcriptional activity has emerged as an effective anticancer strategy. We synthesized four series of disubstituted quindoline derivatives by introducing the second cationic amino side chain and 5-N-methyl group based on a previous study of SYUIQ-5 (1) as c-MYC promoter G-quadruplex ligands. The in vitro evaluations showed that all new compounds exhibited higher stabilities and binding affinities, and most of them had better selectivity (over duplex DNA) for the c-MYC G-quadruplex compared to 1. Moreover, the new ligands prevented NM23-H2, a transcription factor, from effectively binding to the c-MYC G-quadruplex. Further studies showed that the selected ligand, 7a4, down-regulated c-MYC transcription by targeting promoter G-quadruplex and disrupting the NM23-H2/c-MYC interaction in RAJI cells. 7a4 could inhibit Burkitt's lymphoma cell proliferation through cell cycle arrest and apoptosis and suppress tumor growth in a human Burkitt's lymphoma xenograft.
Assuntos
Alcaloides/farmacologia , Antineoplásicos/farmacologia , Linfoma de Burkitt/tratamento farmacológico , Indóis/farmacologia , Proteínas Proto-Oncogênicas c-myc/antagonistas & inibidores , Quinolinas/farmacologia , Alcaloides/síntese química , Alcaloides/química , Animais , Antineoplásicos/síntese química , Antineoplásicos/química , Apoptose/efeitos dos fármacos , Linfoma de Burkitt/genética , Linfoma de Burkitt/patologia , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Quadruplex G/efeitos dos fármacos , Humanos , Indóis/síntese química , Indóis/química , Camundongos Endogâmicos NOD , Camundongos SCID , Estrutura Molecular , Neoplasias Experimentais/tratamento farmacológico , Neoplasias Experimentais/genética , Neoplasias Experimentais/patologia , Proteínas Proto-Oncogênicas c-myc/genética , Quinolinas/síntese química , Quinolinas/química , Relação Estrutura-Atividade , Transcrição Gênica/efeitos dos fármacosRESUMO
To efficiently identify small molecules binding to a G-quadruplex structure while avoiding binding to duplex DNA, we performed a multistep structure-based virtual screening by simultaneously taking into account G-quadruplex DNA and duplex DNA. Among the 13 compounds selected, one outstanding ligand shows significant selectivity for G-quadruplex binding as determined using SPR, FRET-based competition and luciferase activity assay.