RESUMO
The development and progression of solid tumors is dependent on cancer cell autonomous drivers and the tumor microenvironment (TME). Cancer-associated fibroblasts (CAFs) in the TME possess both tumor-promoting and tumor-restraining functions. In the current study, we interrogated the role of αSMA+ CAFs in a genetic mouse model of metastatic colorectal cancer (CRC). Selective depletion of αSMA+ CAFs resulted in increased tumor invasiveness, lymph node metastasis, and reduced overall survival. Depletion of αSMA+ CAFs reduced BMP4 and increased TGFß1 secretion from stromal cells, and was associated with increased Lgr5+ cancer stem-like cells (CSCs) and the generation of an immunosuppressive TME with increased frequency of Foxp3+ regulatory T cells and suppression of CD8+ T cells. This study demonstrates that αSMA+ CAFs in CRC exert tumor-restraining functions via BMP4/TGFß1 paracrine signaling that serves to suppress Lgr5+ CSCs and promote anti-tumor immunity, ultimately limiting CRC progression.
Assuntos
Actinas/metabolismo , Fibroblastos Associados a Câncer/metabolismo , Fibroblastos Associados a Câncer/patologia , Neoplasias Colorretais/metabolismo , Neoplasias Colorretais/patologia , Células-Tronco Neoplásicas/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Animais , Proteína Morfogenética Óssea 4/metabolismo , Linfócitos T CD8-Positivos/metabolismo , Linfócitos T CD8-Positivos/patologia , Linhagem Celular Tumoral , Movimento Celular/fisiologia , Progressão da Doença , Fatores de Transcrição Forkhead/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Invasividade Neoplásica/patologia , Células-Tronco Neoplásicas/patologia , Linfócitos T Reguladores/metabolismo , Linfócitos T Reguladores/patologia , Fator de Crescimento Transformador beta1/metabolismo , Microambiente Tumoral/fisiologiaRESUMO
Even though pancreatic ductal adenocarcinoma (PDAC) is associated with fibrotic stroma, the molecular pathways regulating the formation of cancer associated fibroblasts (CAFs) are not well elucidated. An epigenomic analysis of patient-derived and de-novo generated CAFs demonstrated widespread loss of cytosine methylation that was associated with overexpression of various inflammatory transcripts including CXCR4. Co-culture of neoplastic cells with CAFs led to increased invasiveness that was abrogated by inhibition of CXCR4. Metabolite tracing revealed that lactate produced by neoplastic cells leads to increased production of alpha-ketoglutarate (aKG) within mesenchymal stem cells (MSCs). In turn, aKG mediated activation of the demethylase TET enzyme led to decreased cytosine methylation and increased hydroxymethylation during de novo differentiation of MSCs to CAF. Co-injection of neoplastic cells with TET-deficient MSCs inhibited tumor growth in vivo. Thus, in PDAC, a tumor-mediated lactate flux is associated with widespread epigenomic reprogramming that is seen during CAF formation.
Assuntos
Fibroblastos Associados a Câncer/patologia , Reprogramação Celular/efeitos dos fármacos , Epigênese Genética/efeitos dos fármacos , Ácido Láctico/farmacologia , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patologia , 5-Metilcitosina/análogos & derivados , 5-Metilcitosina/metabolismo , Animais , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/patologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Transformação Celular Neoplásica/efeitos dos fármacos , Reprogramação Celular/genética , Metilação de DNA/efeitos dos fármacos , Humanos , Ácidos Cetoglutáricos/metabolismo , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/metabolismo , Camundongos , Invasividade Neoplásica , Receptores CXCR4/metabolismo , Células Estromais/efeitos dos fármacos , Células Estromais/metabolismo , Transcriptoma/genética , Neoplasias PancreáticasRESUMO
Lymphocyte homing, which contributes to inflammation, has been studied extensively in the small intestine, but there is little known about homing to the large intestine, the site most commonly affected in inflammatory bowel disease. GPR15, an orphan heterotrimeric guanine nucleotide-binding protein (G protein)-coupled receptor, controlled the specific homing of T cells, particularly FOXP3(+) regulatory T cells (Tregs), to the large intestine lamina propria (LILP). GPR15 expression was modulated by gut microbiota and transforming growth factor-ß1, but not by retinoic acid. GPR15-deficient mice were prone to develop more severe large intestine inflammation, which was rescued by the transfer of GPR15-sufficient Tregs. Our findings thus describe a T cell-homing receptor for LILP and indicate that GPR15 plays a role in mucosal immune tolerance largely by regulating the influx of Tregs.
Assuntos
Mucosa Intestinal/imunologia , Intestino Grosso/imunologia , Receptores Acoplados a Proteínas G/metabolismo , Receptores de Retorno de Linfócitos/metabolismo , Receptores de Peptídeos/metabolismo , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo , Animais , Citrobacter rodentium , Colite/imunologia , Colo/imunologia , Infecções por Enterobacteriaceae/imunologia , Infecções por Helicobacter/imunologia , Homeostase , Humanos , Tolerância Imunológica , Intestino Grosso/microbiologia , Intestino Delgado/imunologia , Metagenoma/fisiologia , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Receptores Acoplados a Proteínas G/genética , Receptores de Peptídeos/genéticaRESUMO
Dendritic cells (DC) are antigen-presenting cells found in both lymphoid and nonlymphoid organs, including the brain (bDC) of Cd11c/eyfp transgenic C57BL/6 mice. Using an intranasal vesicular stomatitis virus infection, we demonstrated that EYFP(+) cells amass in areas associated with viral antigens, take on an activated morphology, and project their processes into infected neuronal tissue within the olfactory bulb. These bDC separated into three EYFP(+) CD45(+) CD11b(+) populations, all but one being able to functionally promote both T lymphocyte proliferation and T(H)1 cytokine production. One population was shown to emanate from the brain and a second population was peripherally derived. The third population was of indeterminate origin, being both radiosensitive and not replenished by donor bone marrow. Finally, each EYFP(+) population contained CD11b(+) CD103(+) subpopulations and could be distinguished in terms of CD115, Gr-1, and Ly-6C expression, highlighting mucosal and monocyte-derived DC lineages.