6533b857fe1ef96bd12b3a29
RESEARCH PRODUCT
Inhibition of VEGF expression through blockade of Hif1a and STAT3 signalling mediates the anti-angiogenic effect of melatonin in HepG2 liver cancer cells.
A García-palomoMarta BenetJavier González-gallegoRaquel OrdóñezRamiro JoverSara Carbajo-pescadorJosé L. Maurizsubject
STAT3 Transcription FactorTranscriptional ActivationVascular Endothelial Growth Factor ACancer ResearchCarcinoma HepatocellularTranscription GeneticAngiogenesisAngiogenesis InhibitorsApoptosismelatoninP300-CBP Transcription FactorsHif1αBiologyMelatoninSTAT3chemistry.chemical_compoundHypoxia-Inducible Factor 1-AlphamedicineHuman Umbilical Vein Endothelial CellsHumansp300-CBP Transcription FactorsSTAT3Promoter Regions GeneticTube formationNeovascularization PathologicLiver NeoplasmsCobaltHep G2 Cellshepatocellular carcinomaHypoxia-Inducible Factor 1 alpha SubunitVEGFCell Hypoxiadigestive system diseasesCyclic S-OxidesVascular endothelial growth factorGene Expression Regulation NeoplasticVascular endothelial growth factor AOncologychemistryCancer researchbiology.proteinTranslational Therapeuticsmedicine.drugSignal Transductiondescription
Background: Hepatocellular carcinoma (HCC) growth relies on angiogenesis via vascular endothelial growth factor (VEGF) release. Hypoxia within tumour environment leads to intracellular stabilisation of hypoxia inducible factor 1 alpha (Hif1α) and signal transducer and activator of transcription (STAT3). Melatonin induces apoptosis in HCC, and shows anti-angiogenic features in several tumours. In this study, we used human HepG2 liver cancer cells as an in vitro model to investigate the anti-angiogenic effects of melatonin. Methods: HepG2 cells were treated with melatonin under normoxic or CoCl2-induced hypoxia. Gene expression was analysed by RT–qPCR and western blot. Melatonin-induced anti-angiogenic activity was confirmed by in vivo human umbilical vein endothelial cells (HUVECs) tube formation assay. Secreted VEGF was measured by ELISA. Immunofluorescence was performed to analyse Hif1α cellular localisation. Physical interaction between Hif1α and its co-activators was analysed by immunoprecipitation and chromatin immunoprecipitation (ChIP). Results: Melatonin at a pharmacological concentration (1 mℳ) decreases cellular and secreted VEGF levels, and prevents HUVECs tube formation under hypoxia, associated with a reduction in Hif1α protein expression, nuclear localisation, and transcriptional activity. While hypoxia increases phospho-STAT3, Hif1α, and CBP/p300 recruitment as a transcriptional complex within the VEGF promoter, melatonin 1 mℳ decreases their physical interaction. Melatonin and the selective STAT3 inhibitor Stattic show a synergic effect on Hif1α, STAT3, and VEGF expression. Conclusion: Melatonin exerts an anti-angiogenic activity in HepG2 cells by interfering with the transcriptional activation of VEGF, via Hif1α and STAT3. Our results provide evidence to consider this indole as a powerful anti-angiogenic agent for HCC treatment.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2013-06-11 |