RESUMO
Tumour-associated macrophages facilitate cancer progression, but whether they can be reprogrammed to elicit an anti-tumour response remains unclear. Deletion of the microRNA-processing enzyme Dicer is now shown to rewire macrophages to an anti-tumour mode, leading to an enhanced response to immunotherapy and inhibition of tumour progression.
Assuntos
Macrófagos/imunologia , Neoplasias/imunologia , Ribonuclease III/metabolismo , Animais , Reprogramação Celular , Progressão da Doença , Humanos , Imunoterapia/métodos , Neoplasias/diagnóstico , Neoplasias/terapia , Ribonuclease III/imunologiaRESUMO
PURPOSE: Human tumors consist of heterogeneous populations of cells with distinct marker expression and functional properties. In squamous cell carcinoma of the head and neck (SCCHN), CD44 is a well-characterized marker of a resilient subpopulation of cells associated with increased tumorigenesis, radioresistance, and chemoresistance. Evidence indicates that these cells have an immunosuppressive phenotype; however, mechanisms have been elusive. EXPERIMENTAL DESIGN: Using primary human SCCHN tumor samples and patient-derived xenografts, we examined the phenotypes of subsets of tumor cells and investigated mechanisms regulating their immunogenicity. RESULTS: CD44(+) cells in primary human SCCHN were found to have an epithelial-to-mesenchymal (EMT) phenotype and were less immunogenic than CD44(-) cells when cultured with autologous CD8(+) tumor-infiltrating T cells. Selective expression of the programmed death-ligand 1 (PD-L1) was observed on CD44(+) cells compared with CD44(-) cells and was associated with constitutive phosphorylation of STAT3 on CD44(+) cells. Importantly, inhibition of STAT3 decreased expression of PD-L1 on CD44(+) cells. IFNγ treatment preferentially induced even further PD-L1 expression on CD44(+) cells and was associated with enhanced IFNγ receptor expression and phosphorylation of STAT1. Finally, the decreased immunogenicity of CD44(+) cells was partially reversed by antibody blockade of the programmed death 1 (PD-1) receptor, indicating that the differences in PD-L1 expression between CD44(+) and CD44(-) cells are biologically and clinically relevant. CONCLUSIONS: Our findings provide a mechanism by which long-lived CD44(+) tumor-initiating cells can selectively evade host immune responses and provide rationale for targeting the PD-1 pathway in the adjuvant therapy setting of SCCHN. Clin Cancer Res; 22(14); 3571-81. ©2016 AACR.
Assuntos
Antígeno B7-H1/metabolismo , Linfócitos T CD8-Positivos/imunologia , Carcinoma de Células Escamosas/imunologia , Carcinoma de Células Escamosas/metabolismo , Neoplasias de Cabeça e Pescoço/imunologia , Neoplasias de Cabeça e Pescoço/metabolismo , Receptores de Hialuronatos/metabolismo , Animais , Linfócitos T CD8-Positivos/metabolismo , Transição Epitelial-Mesenquimal/imunologia , Transição Epitelial-Mesenquimal/fisiologia , Humanos , Camundongos , Fator de Transcrição STAT1/metabolismo , Fator de Transcrição STAT3/metabolismo , Carcinoma de Células Escamosas de Cabeça e PescoçoRESUMO
PURPOSE: The ErbB3-binding protein 1 (Ebp1) has been implicated in diverse cancers as having either oncogenic or tumor suppressor activities. The present study was undertaken to determine the effects of Ebp1 expression in AML cells and to determine the mechanisms by which Ebp1 promotes cell proliferation in these cells. EXPERIMENTAL DESIGN: The expression of Ebp1 was studied in mononuclear cells obtained from the peripheral blood of 54 patients with AML by Western blot analysis. The effects of Ebp1 expression on proliferating cell nuclear antigen (PCNA) expression and cell proliferation was measured using Western blot analysis, immunoprecipitation, in vitro ubiquitination, and colony-forming assays. The role of Ebp1 in promoting rRNA synthesis and cell proliferation was evaluated by measuring the level of pre-rRNA and the recruitment of Pol I to rDNA. RESULTS: Ebp1 is highly expressed in acute myelogenous leukemia (AML) cells and regulates the level of ribosomal RNA (rRNA) synthesis by binding to RNA Polymerase I (Pol I) and enhancing the formation of the Pol I initiation complex. Ebp1 also increases the stability of PCNA protein by preventing its interaction with Mdm2, for which it is a substrate. CONCLUSIONS: These results demonstrate an important role of Ebp1 in promoting cell proliferation in AML cells through the regulation of both rRNA synthesis and PCNA expression. Clin Cancer Res; 22(13); 3320-7. ©2016 AACR.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Leucemia Mieloide Aguda/patologia , Antígeno Nuclear de Célula em Proliferação/biossíntese , RNA Ribossômico/biossíntese , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Receptor ErbB-3/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/biossíntese , Animais , Proliferação de Células , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Proto-Oncogênicas c-mdm2/metabolismo , Interferência de RNA , RNA Interferente Pequeno/genética , Proteínas de Ligação a RNA/biossíntese , Células Tumorais Cultivadas , UbiquitinaçãoRESUMO
Infection-driven inflammation has been proposed to be involved in the tumorigenesis of head and neck squamous cell carcinoma (HNSCC). Oral HNSCC is often colonized with microbes such as gram-positive bacteria and yeast, where ligands derived from their wall components have been shown to specifically bind to Toll-like receptor 2 (TLR2). Although TLR2 has been described to be expressed in oral HNSCC, its function has not been well characterized. Here, we show the expression of TLR2 in both HNSCC cell lines and primary patient-derived HNSCC xenograft tumors. Activation of TLR2 with a yeast-derived ligand of TLR2, zymosan, promoted organoid formation in an ex vivo model of tumor growth, while blockade with anti-TLR2 antibodies inhibited organoid formation. Zymosan also induced phosphorylation of ERK and the p65 subunit of NF-κB, which was inhibited in the presence of anti-TLR2 antibodies, indicating that this receptor is functional in HNSCC and that the signaling through these pathways is intact. TLR2 blockade also inhibited growth of human xenografted tumors in immunodeficient mice. In summary, our data show that TLR2 is a functional receptor expressed in human HNSCC that plays a direct pro-tumorigenic role, and that it can be therapeutically targeted with blocking antibodies to reduce tumor growth.
Assuntos
Anticorpos Monoclonais/farmacologia , Carcinoma de Células Escamosas/patologia , Carcinoma de Células Escamosas/terapia , Neoplasias de Cabeça e Pescoço/patologia , Neoplasias de Cabeça e Pescoço/terapia , Receptor 2 Toll-Like/antagonistas & inibidores , Receptor 2 Toll-Like/biossíntese , Animais , Anticorpos Monoclonais/imunologia , Carcinoma de Células Escamosas/metabolismo , Processos de Crescimento Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Neoplasias de Cabeça e Pescoço/metabolismo , Humanos , Sistema de Sinalização das MAP Quinases , Camundongos , Camundongos Endogâmicos BALB C , Terapia de Alvo Molecular , NF-kappa B/metabolismo , Carcinoma de Células Escamosas de Cabeça e Pescoço , Receptor 2 Toll-Like/imunologia , Receptor 2 Toll-Like/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto , Zimosan/farmacologiaRESUMO
Mycophenolic acid (MPA) is the active metabolite of mycophenolate mofetil, an effective immunosuppressive drug. Both MPA and mycophenolate mofetil are highly specific inhibitors of guanine nucleotide synthesis and of T-cell activation. However, the mechanism by which guanine nucleotide depletion suppresses T-cell activation is unknown. Depletion of GTP inhibits ribosomal RNA synthesis in T cells by inhibiting transcription initiation factor I (TIF-IA), a GTP-binding protein that recruits RNA polymerase I to the ribosomal DNA promoter. TIF-IA-GTP binds the ErbB3-binding protein 1, and together they enhance the transcription of proliferating cell nuclear antigen (PCNA). GTP binding by TIF-IA and ErbB3-binding protein 1 phosphorylation by protein kinase C δ are both required for optimal PCNA expression. The protein kinase C inhibitor sotrastaurin markedly potentiates the inhibition of ribosomal RNA synthesis, PCNA expression, and T-cell activation induced by MPA, suggesting that the combination of the two agents are more highly effective than either alone in inducing immunosuppression.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Guanosina Trifosfato/metabolismo , RNA Ribossômico/biossíntese , Proteínas de Ligação a RNA/metabolismo , Linfócitos T/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Western Blotting , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , DNA Ribossômico/genética , Expressão Gênica/efeitos dos fármacos , Células HEK293 , Humanos , Células Jurkat , Queratina-20/genética , Queratina-20/metabolismo , Ativação Linfocitária/efeitos dos fármacos , Mutação , Ácido Micofenólico/farmacologia , Fosforilação/efeitos dos fármacos , Proteínas Pol1 do Complexo de Iniciação de Transcrição/genética , Proteínas Pol1 do Complexo de Iniciação de Transcrição/metabolismo , Antígeno Nuclear de Célula em Proliferação/genética , Antígeno Nuclear de Célula em Proliferação/metabolismo , Regiões Promotoras Genéticas/genética , Ligação Proteica/efeitos dos fármacos , Proteína Quinase C-delta/antagonistas & inibidores , Proteína Quinase C-delta/metabolismo , Pirróis/farmacologia , Quinazolinas/farmacologia , Interferência de RNA , RNA Polimerase I/metabolismo , RNA Ribossômico/genética , Proteínas de Ligação a RNA/genética , Linfócitos T/efeitos dos fármacosRESUMO
Myelomonocytic cells play a key role in the progression of many solid tumors. However, very little is known about their contribution to the progression of hematopoietic cancers. We investigated the role of monocytes in the progression of human B-cell precursor acute lymphoblastic leukemia (BCP-ALL). We demonstrated that coculturing human monocytes in vitro with CD19+ BCP-ALL blasts from patients "conditioned" them to an inflammatory phenotype characterized by significant up-regulation of the chemokine, CXCL10. This phenotype was also observable ex vivo in monocytes isolated from BCP-ALL patients, which show elevated CXCL10 production compared with monocytes from healthy donors. Functionally, the "conditioned" monocytes promoted migration and invasive capacity of BCP-ALL cells. Increased invasion was mediated by matrix metalloproteinase 9 expression and activity in the BCP-ALL cells induced by the monocyte-derived CXCL10. However, neither the "conditioned" monocytes nor the CXCL10 produced by these cells had any effect on the proliferation/viability of BCP-ALL cells and angiogenesis. Collectively, our results strongly suggest a protumoral role for human monocytes in BCP-ALL, orchestrated by CXCL10 and its effect on tumor cell migration and invasion. These observations highlight the importance of the CXCL10/CXCR3 chemokine circuit in BCP-ALL progression.