RESUMO
As substantial constituents of the multiple myeloma (MM) microenvironment, pro-inflammatory macrophages have emerged as key promoters of disease progression, bone destruction, and immune impairment. We identify beta-2-microglobulin (ß2m) as a driver in initiating inflammation in myeloma-associated macrophages (MAMs). Lysosomal accumulation of phagocytosed ß2m promotes ß2m amyloid aggregation in MAMs, resulting in lysosomal rupture and ultimately production of active interleukin-1ß (IL-1ß) and IL-18. This process depends on activation of the NLRP3 inflammasome after ß2m accumulation, as macrophages from NLRP3-deficient mice lack efficient ß2m-induced IL-1ß production. Moreover, depletion or silencing of ß2m in MM cells abrogates inflammasome activation in a murine MM model. Finally, we demonstrate that disruption of NLRP3 or IL-18 diminishes tumor growth and osteolytic bone destruction normally promoted by ß2m-induced inflammasome signaling. Our results provide mechanistic evidence for ß2m's role as an NLRP3 inflammasome activator during MM pathogenesis. Moreover, inhibition of NLRP3 represents a potential therapeutic approach in MM.
Assuntos
Amiloide/metabolismo , Mieloma Múltiplo/patologia , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Macrófagos Associados a Tumor/metabolismo , Microglobulina beta-2/metabolismo , Animais , Células Cultivadas , Humanos , Inflamação/imunologia , Interleucina-18/metabolismo , Interleucina-1beta/metabolismo , Lisossomos/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Fagocitose/imunologia , Transdução de Sinais/imunologia , Microambiente Tumoral/imunologia , Macrófagos Associados a Tumor/imunologia , Microglobulina beta-2/genéticaRESUMO
The bone marrow microenvironment (BMME) is key player in regulation and maintenance of hematopoiesis. Oncogenic RAS mutations, causing constitutive activation of multiple tumor-promoting pathways, are frequently found in human cancer. So far in hematologic malignancies, RAS mutations have only been reported to occur in hematopoietic cells. In this study, we investigated the effect of oncogenic Kras expression in the BMME in a chimeric mouse model. We observed that an activating mutation of Kras in the nonhematopoietic system leads to a phenotype resembling myelodysplastic syndrome (MDS) characterized by peripheral cytopenia, marked dysplasia within the myeloid lineage as well as impaired proliferation and differentiation capacity of hematopoietic stem and progenitor cells. The phenotypic changes could be reverted when the BM was re-isolated and transferred into healthy recipients, indicating that the KrasG12D -activation in the nonhematopoietic BMME was essential for the MDS phenotype. Gene expression analysis of sorted nonhematopoietic BM niche cells from KrasG12D mice revealed upregulation of multiple inflammation-related genes including IL1-superfamily members (Il1α, Il1ß, Il1f9) and the NLPR3 inflammasome. Thus, pro-inflammatory IL1-signaling in the BMME may contribute to MDS development. Our findings show that a single genetic change in the nonhematopoietic BMME can cause an MDS phenotype. Oncogenic Kras activation leads to pro-inflammatory signaling in the BMME which impairs HSPCs function. IMPLICATIONS: These findings may help to identify new therapeutic targets for MDS.
Assuntos
Células da Medula Óssea/patologia , Transformação Celular Neoplásica/patologia , Células-Tronco Hematopoéticas/patologia , Mutação , Síndromes Mielodisplásicas/patologia , Proteínas Proto-Oncogênicas p21(ras)/genética , Microambiente Tumoral , Animais , Células da Medula Óssea/metabolismo , Diferenciação Celular , Proliferação de Células , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/metabolismo , Células-Tronco Hematopoéticas/metabolismo , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Síndromes Mielodisplásicas/etiologia , Síndromes Mielodisplásicas/metabolismo , Fenótipo , Transdução de SinaisRESUMO
Inflammation is involved in tumor development and progression as well as antitumor response to therapy. In the past decade, the crosstalk between inflammation, immunity, and cancer has been investigated extensively, which led to the identification of several underlying mechanisms and cells involved. The formation of inflammasome complexes leads to the activation of caspase-1, production of interleukin (IL)-1ß, and IL-18 and pyroptosis. Multiple studies have shown the involvement of NLRP3 inflammasome in tumorigenesis. Conversely, other reports have indicated a protective role in certain cancers. In this review, we summarize these contradictory roles of NLRP3 inflammasome in cancer, shed the light on oncogenic signaling leading to NLRP3 activation and IL-1ß production and outline the current knowledge on therapeutic approaches.
Assuntos
Inflamassomos/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Neoplasias/imunologia , Animais , Humanos , Inflamação , Interleucina-1beta/metabolismo , Terapia de Alvo Molecular , Piroptose , Transdução de SinaisRESUMO
Oncogenic KRAS mutations are the most frequent mutations in human cancer, but most difficult to target. While sustained proliferation caused by oncogenic KRAS-downstream signalling is a main driver of carcinogenesis, there is increasing evidence that it also mediates autocrine effects and crosstalk with the tumour microenvironment (TME). Here, we discuss recent reports connecting KRAS mutations with tumour-promoting inflammation and immune modulation caused by KRAS that leads to immune escape in the TME. We discuss the preclinical work on KRAS-induced inflammation and immune modulation in the context of currently ongoing clinical trials targeting cancer entities that carry KRAS mutations and strategies to overcome the oncogene-induced effects on the immune system.
Assuntos
Carcinogênese/genética , Carcinogênese/imunologia , Imunomodulação/genética , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteínas Proto-Oncogênicas p21(ras)/imunologia , Animais , Humanos , Inflamação/genética , Inflamação/imunologia , Camundongos , Modelos Imunológicos , Transdução de Sinais/genética , Transdução de Sinais/imunologia , Pesquisa Translacional BiomédicaRESUMO
Acute graft-versus-host disease (GVHD) can affect the central nervous system (CNS). The role of microglia in CNS-GVHD remains undefined. In agreement with microglia activation, we found that profound morphological changes and MHC-II and CD80 upregulation occurred upon GVHD induction. RNA sequencing-based analysis of purified microglia obtained from mice with CNS-GVHD revealed TNF upregulation. Selective TNF gene deletion in microglia of Cx3cr1creER Tnffl/- mice reduced MHC-II expression and decreased CNS T cell infiltrates and VCAM-1+ endothelial cells. GVHD increased microglia TGF-ß-activated kinase-1 (TAK1) activation and NF-κB/p38 MAPK signaling. Selective Tak1 deletion in microglia using Cx3cr1creER Tak1fl/fl mice resulted in reduced TNF production and microglial MHC-II and improved neurocognitive activity. Pharmacological TAK1 inhibition reduced TNF production and MHC-II expression by microglia, Th1 and Th17 T cell infiltrates, and VCAM-1+ endothelial cells and improved neurocognitive activity, without blocking graft-versus-leukemia effects. Consistent with these findings in mice, we observed increased activation and TNF production of microglia in the CNS of GVHD patients. In summary, we prove a role for microglia in CNS-GVHD, identify the TAK1/TNF/MHC-II axis as a mediator of CNS-GVHD, and provide a TAK1 inhibitor-based approach against GVHD-induced neurotoxicity.
Assuntos
Doenças do Sistema Nervoso Central/imunologia , Doença Enxerto-Hospedeiro/imunologia , Microglia/imunologia , Fator de Necrose Tumoral alfa/imunologia , Regulação para Cima/imunologia , Doença Aguda , Animais , Receptor 1 de Quimiocina CX3C/genética , Receptor 1 de Quimiocina CX3C/imunologia , Doenças do Sistema Nervoso Central/genética , Doenças do Sistema Nervoso Central/patologia , Modelos Animais de Doenças , Doença Enxerto-Hospedeiro/genética , Doença Enxerto-Hospedeiro/patologia , Antígenos de Histocompatibilidade Classe II/genética , Antígenos de Histocompatibilidade Classe II/imunologia , Humanos , MAP Quinase Quinase Quinases/genética , MAP Quinase Quinase Quinases/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Microglia/patologia , Células Th1/imunologia , Células Th1/patologia , Células Th17/imunologia , Células Th17/patologia , Fator de Necrose Tumoral alfa/genética , Molécula 1 de Adesão de Célula Vascular/genética , Molécula 1 de Adesão de Célula Vascular/imunologiaRESUMO
Oncogenic Ras mutations occur in various leukemias. It was unclear if, besides the direct transforming effect via constant RAS/MEK/ERK signaling, an inflammation-related effect of KRAS contributes to the disease. Here, we identify a functional link between oncogenic KrasG12D and NLRP3 inflammasome activation in murine and human cells. Mice expressing active KrasG12D in the hematopoietic system developed myeloproliferation and cytopenia, which is reversed in KrasG12D mice lacking NLRP3 in the hematopoietic system. Therapeutic IL-1-receptor blockade or NLRP3-inhibition reduces myeloproliferation and improves hematopoiesis. Mechanistically, KrasG12D-RAC1 activation induces reactive oxygen species (ROS) production causing NLRP3 inflammasome-activation. In agreement with our observations in mice, patient-derived myeloid leukemia cells exhibit KRAS/RAC1/ROS/NLRP3/IL-1ß axis activity. Our findings indicate that oncogenic KRAS not only act via its canonical oncogenic driver function, but also enhances the activation of the pro-inflammatory RAC1/ROS/NLRP3/IL-1ß axis. This paves the way for a therapeutic approach based on immune modulation via NLRP3 blockade in KRAS-mutant myeloid malignancies.