RESUMO
The motility, angiogenesis and metastasis-stimulating factor Autotaxin (Atx), over expressed by human neuroblastomas (NB), is constitutively expressed by human Nmyc-amplified SK-N-BE and non-Nmyc-amplified SH-SY5Y NB cells. Here, we characterise a novel Atx transcriptional mechanism, utilised by both cell lines, that is restricted to the first 285bp of the Atx promoter and involves AP-1 and SP transcription factors, acting through a CRE/AP-1-like element at position -142 to -149 and a GAbox at position -227 to -235 relative to the Atx translational start site. This novel transcriptional mechanism can be inhibited by internally initiated SP-3 and the natural phenol curcumin.
Assuntos
Curcumina/farmacologia , Neuroblastoma/patologia , Diester Fosfórico Hidrolases/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo , Fatores de Transcrição Sp/metabolismo , Fator de Transcrição AP-1/metabolismo , Transcrição Gênica/efeitos dos fármacos , Linhagem Celular Tumoral , AMP Cíclico/genética , Deleção de Genes , Genes Reporter/genética , Humanos , Diester Fosfórico Hidrolases/deficiência , Elementos de Resposta/efeitos dos fármacos , Elementos de Resposta/genética , Ativação Transcricional/efeitos dos fármacosRESUMO
Irreversible MMP-9 inhibition is considered a significant therapeutic goal in inflammatory, vascular and tumour pathology. We report that divalent cation chelators Alendronate and EDTA not only directly inhibited MMP-9 but also promoted irreversible plasmin-mediated MMP-9 inactivation by exposing cryptic plasmin-degradation sites within the MMP-9 catalytic-domain and producing an inhibitory hemopexin-domain fragment. This effect was also observed using MDA-MB-231 breast cancer cells, which activated exogenous plasminogen to degrade endogenous proMMP-9 in the presence of Alendronate or EDTA. Degradation-mediated inactivation of proMMP-9 occurred in the absence of transient activation, attesting to the incapacity of plasmin to directly activate proMMP-9 and direct MMP-9 inhibition by Alendronate and EDTA. Our study provides a novel rational for therapeutic Alendronate use in MMP-9-dependent pathology characterised by plasminogen activation.
Assuntos
Alendronato/farmacologia , Fibrinolisina/metabolismo , Metaloproteinase 9 da Matriz/metabolismo , Catálise , Domínio Catalítico , Cátions , Linhagem Celular Tumoral , Quelantes/farmacologia , Relação Dose-Resposta a Droga , Ácido Edético/química , Hemopexina/química , Humanos , Plasminogênio/química , Estrutura Terciária de Proteína , Proteínas Recombinantes/químicaRESUMO
Increased expression of thioredoxin (Trx)-1 and matrix metalloproteinase (MMP)-9 associates with malignant breast cancer progression. Here, we describe a functional relationship between Trx-1 and MMP-9 in promoting MDA-MB-231 breast cancer cell invasive behaviour. Trx-1 overexpression stimulated MMP-9 expression, de-regulated the MMP-9/TIMP-1 equilibrium and augmented MMP-9 involvement in a more invasive phenotype. Trx-1 augmented MMP-9 transcription through NF-κB, AP-1 and SP1 elements; stimulated p50/p65 NF-κB activity and recruitment to the MMP-9 promoter; and facilitated MMP-9 promoter-accessibility to NF-κB by preventing HDAC recruitment and maintaining MMP-9 promoter histone acetylation. Our data provide a functional basis for Trx-1 and MMP-9 association in malignant breast cancer and identify Trx-1 and NF-κB as potentially druggable targets for reducing MMP-9 involvement in malignant behaviour.
