RESUMO
Considering that Aurora kinase inhibitors are currently under clinical investigation in hematologic cancers, the identification of molecular events that limit the response to such agents is essential for enhancing clinical outcomes. Here, we discover a NF-κB-inducing kinase (NIK)-c-Abl-STAT3 signaling-centered feedback loop that restrains the efficacy of Aurora inhibitors in multiple myeloma. Mechanistically, we demonstrate that Aurora inhibition promotes NIK protein stabilization via downregulation of its negative regulator TRAF2. Accumulated NIK converts c-Abl tyrosine kinase from a nuclear proapoptotic into a cytoplasmic antiapoptotic effector by inducing its phosphorylation at Thr735, Tyr245 and Tyr412 residues, and, by entering into a trimeric complex formation with c-Abl and STAT3, increases both the transcriptional activity of STAT3 and expression of the antiapoptotic STAT3 target genes PIM1 and PIM2. This consequently promotes cell survival and limits the response to Aurora inhibition. The functional disruption of any of the components of the trimer NIK-c-Abl-STAT3 or the PIM survival kinases consistently enhances the responsiveness of myeloma cells to Aurora inhibitors. Importantly, concurrent inhibition of NIK or c-Abl disrupts Aurora inhibitor-induced feedback activation of STAT3 and sensitizes myeloma cells to Aurora inhibitors, implicating a combined inhibition of Aurora and NIK or c-Abl kinases as potential therapies for multiple myeloma. Accordingly, pharmacological inhibition of c-Abl together with Aurora resulted in substantial cell death and tumor regression in vivo The findings reveal an important functional interaction between NIK, Abl and Aurora kinases, and identify the NIK, c-Abl and PIM survival kinases as potential pharmacological targets for improving the efficacy of Aurora inhibitors in myeloma.
Assuntos
Aurora Quinase A/antagonistas & inibidores , Aurora Quinase B/antagonistas & inibidores , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Mieloma Múltiplo/tratamento farmacológico , Inibidores de Proteínas Quinases/farmacologia , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Proto-Oncogênicas c-abl/metabolismo , Animais , Apoptose , Proliferação de Células , Humanos , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Mieloma Múltiplo/genética , Mieloma Múltiplo/metabolismo , Mieloma Múltiplo/patologia , NF-kappa B/genética , NF-kappa B/metabolismo , Piperazinas/farmacologia , Proteínas Serina-Treonina Quinases/genética , Proteínas Proto-Oncogênicas c-abl/genética , Pirazóis/farmacologia , Pirróis/farmacologia , Fator de Transcrição STAT3/genética , Fator de Transcrição STAT3/metabolismo , Fator 2 Associado a Receptor de TNF/genética , Fator 2 Associado a Receptor de TNF/metabolismo , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto , Quinase Induzida por NF-kappaBRESUMO
Biobased composites with peculiar properties offer an attractive route for producing environmentally friendly materials. The reinforcement for poly(butylene adipate-co-terephthalate) (PBAT), based on zein-titanium dioxide (TiO2) complex (ZTC) microparticles, is presented and used to produce composite filaments, successfully 3-dimensionally (3D) printed by fused deposition modeling (FDM). The outcome of ZTC addition, ranging from 5 to 40 wt %, on the thermo-mechanical properties of composite materials was analyzed. Results reveal that storage modulus increased with increasing the ZTC content, leading to a slight increase in the glass transition temperature. The creep compliance varies with the ZTC concentration, denoting a better resistance to deformation under constant stress conditions for composites with higher complex content. Scanning electron microscopy was used to assess the quality of interphase adhesion between PBAT and ZTC, showing good dispersion and distribution of complex microparticles in the polymer matrix. Infrared spectroscopy confirmed the formation of a valid interface due to the formation of hydrogen bonds between filler and polymer matrix. Preliminary tests on the biocompatibility of these materials were also performed, showing no cytotoxic effects on cell viability. Finally, the 3D printability of biobased composites was demonstrated by realizing complex structures with a commercial FDM printer.
Assuntos
Poliésteres , Polímeros , Excipientes , Microscopia Eletrônica de Varredura , Poliésteres/química , Polímeros/química , Impressão TridimensionalRESUMO
Genomic studies have identified recurrent somatic alterations in genes involved in DNA methylation and post-translational histone modifications in acute lymphoblastic leukemia (ALL), suggesting new opportunities for therapeutic interventions. In this study, we identified G9a/EHMT2 as a potential target in T-ALL through the intersection of epigenome-centered shRNA and chemical screens. We subsequently validated G9a with low-throughput CRISPR-Cas9-based studies targeting the catalytic G9a SET-domain and the testing of G9a chemical inhibitors in vitro, 3D, and in vivo T-ALL models. Mechanistically we determined that G9a repression promotes lysosomal biogenesis and autophagic degradation associated with the suppression of sestrin2 (SESN2) and inhibition of glycogen synthase kinase-3 (GSK-3), suggesting that in T-ALL glycolytic dependent pathways are at least in part under epigenetic control. Thus, targeting G9a represents a strategy to exhaust the metabolic requirement of T-ALL cells.