RESUMO
Pancreatic cancer (PDAC) is one of the most dismal of human malignancies. Inhibiting or delaying the progression of precursor lesions of PDAC, pancreatic intraepthial neoplasia (PanINs), to invasive cancer, would be a major step. In the present study, we used a transgenic murine model of pancreatic cancer to evaluate the impact of a conditional knockout of the transcription factor Snail1, a major factor in epithelial-to-mesenchymal transition, on acinar-to-ductal formation and on PanIN progression. By interbreeding conditional LsL-Snail floxf/wt ; LsL-Kras G12D and Pdx1-Cre strains, we obtained LsL-Kras G12D ;Pdx1-Cre(KP) mice, Snail1 heterozygous knockout LsL-Kras G12D ; LsL-Snail flox/- ;Pdx1-Cre(KPShet) mice or Snail1 homozygous knockout LsL-Kras G12D ;LsL-Snail flox/flox ;Pdx1-Cre(KPS) mice. Mice were then followed in a longitudinal study for 2, 4, 6, 8, 10, and 12 months. Furthermore, in mice with a genetic or pharmacological inhibition of Snail1, using the Snail1 inhibitor GN25, a model of pancreatic injury by administration of cerulein was introduced to evaluate ADM formation in this setting. A translational approach with a tissue microarray (TMA) of human PanINs and an in vivo nude mouse platform to test GN25 in human pancreatic adenocarcinoma was then adopted. Quantification of PanINs showed delayed initiation and progression of PanIN lesions at all ages in both homozygous and heterozygous Snaildel1;Pdx-1-Cre;LSL-KrasG12D/+-Mice. PanINs at TMA revealed snail expression in the majority of cases. GN25 showed growth inhibition in 2/2 human pancreatic adenocarcinomas using a nude mice in vivo platform. Genetic and pharmacologic abrogation of Snail1 signaling in exocrine pancreas impairs development of acinar-to-ductal metaplasia following cerulein-mediated pancreatic injury. The present study suggests a fundamental new approach to delay the progression of PDAC.
Assuntos
Carcinoma Ductal Pancreático/prevenção & controle , Naftoquinonas/uso terapêutico , Pâncreas/patologia , Neoplasias Pancreáticas/prevenção & controle , Lesões Pré-Cancerosas/tratamento farmacológico , Fatores de Transcrição da Família Snail , Animais , Antineoplásicos/uso terapêutico , Carcinoma Ductal Pancreático/genética , Transformação Celular Neoplásica/efeitos dos fármacos , Transformação Celular Neoplásica/genética , Ceruletídeo , Modelos Animais de Doenças , Progressão da Doença , Técnicas de Silenciamento de Genes , Xenoenxertos , Humanos , Metaplasia/induzido quimicamente , Metaplasia/tratamento farmacológico , Metaplasia/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Nus , Camundongos Transgênicos , Pâncreas/efeitos dos fármacos , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patologia , Lesões Pré-Cancerosas/induzido quimicamente , Lesões Pré-Cancerosas/genética , Lesões Pré-Cancerosas/patologia , Fatores de Transcrição da Família Snail/antagonistas & inibidores , Fatores de Transcrição da Família Snail/genética , Células Tumorais CultivadasRESUMO
The Down syndrome-associated DYRK1A kinase has been reported as a stimulator of the developmentally important Hedgehog (Hh) pathway, but cells from Down syndrome patients paradoxically display reduced Hh signalling activity. Here we find that DYRK1A stimulates GLI transcription factor activity through phosphorylation of general nuclear localization clusters. In contrast, in vivo and in vitro experiments reveal that DYRK1A kinase can also function as an inhibitor of endogenous Hh signalling by negatively regulating ABLIM proteins, the actin cytoskeleton and the transcriptional co-activator MKL1 (MAL). As a final effector of the DYRK1A-ABLIM-actin-MKL1 sequence, we identify the MKL1 interactor Jumonji domain demethylase 1A (JMJD1A) as a novel Hh pathway component stabilizing the GLI1 protein in a demethylase-independent manner. Furthermore, a Jumonji-specific small-molecule antagonist represents a novel and powerful inhibitor of Hh signal transduction by inducing GLI1 protein degradation in vitro and in vivo.