RESUMEN
Adoptive transfer of antitumor cytotoxic T cells is an emerging form of cancer immunotherapy. A key challenge to expanding the utility of adoptive cell therapies is how to enhance the survival and function of the transferred T cells. Immune-cell survival requires adaptation to different microenvironments and particularly to the hypoxic milieu of solid tumors. The hypoxia-inducible factor (HIF) transcription factors are an essential aspect of this adaptation. In this study, we undertook experiments to define structural determinants of HIF that potentiate antitumor efficacy in cytotoxic T cells. We first created retroviral vectors to deliver ectopic expression of HIF1α and HIF2α in mouse CD8+ T cells, together or individually and with or without sensitivity to the oxygen-dependent HIFα inhibitors Von Hippel-Lindau and factor-inhibiting HIF (FIH). HIF2α, but not HIF1α, drove broad transcriptional changes in CD8+ T cells, resulting in increased cytotoxic differentiation and cytolytic function against tumor targets. A specific mutation replacing the hydroxyl group-acceptor site for FIH in HIF2α gave rise to the most effective antitumor T cells after adoptive transfer in vivo In addition, codelivering an FIH-insensitive form of HIF2α with an anti-CD19 chimeric antigen receptor greatly enhanced cytolytic function of human CD8+ T cells against lymphoma cells both in vitro and in a xenograft adoptive transfer model. These experiments point to a means to increase the antitumor efficacy of therapeutic CD8+ T cells via ectopic expression of the HIF transcription factor.See related Spotlight on p. 364.
Asunto(s)
Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/inmunología , Linfocitos T CD8-positivos/inmunología , Subunidad alfa del Factor 1 Inducible por Hipoxia/inmunología , Hipoxia/inmunología , Inmunoterapia Adoptiva , Animales , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/antagonistas & inhibidores , Línea Celular Tumoral , Femenino , Humanos , Subunidad alfa del Factor 1 Inducible por Hipoxia/antagonistas & inhibidores , Masculino , Ratones , Ratones Endogámicos C57BL , Factores de Transcripción , Microambiente TumoralRESUMEN
Hypoxia causes dramatic changes in gene expression profiles, and the mechanism of hypoxia-inducible transcription has been analyzed for use as a model system of stress-inducible gene regulation. In this study, changes in chromatin organization in promoters of hypoxia-inducible genes were investigated during hypoxia-reoxygenation conditions. Most of the hypoxia-inducible gene promoters were hypersensitive to DNase I under both normal and hypoxic conditions, and our data indicate an immediate recruitment of transcription factors under hypoxic conditions. In some of the hypoxia-inducible promoters, nucleosome-free DNA regions (NFRs) were established in parallel with hypoxia-induced transcription. We also show that the hypoxia-inducible formation of NFRs requires that hypoxia-inducible transcription factors (HIFs) bind to the promoters together with the transcriptional coactivator CBP. Within 1â¯h after the hypoxia exposure was ended (reoxygenation), HIF complexes were dissociated from the promoter regions. Within 24â¯h of reoxygenation, the hypoxia-induced transcription returned to basal levels and the nucleosome structure was reassembled in the hypoxia-inducible NFRs. Nucleosome reassembly required the function of the transcriptional coregulator SIN3A. Thus, reversible changes in nucleosome organization mediated by transcription factors are notable features of stress-inducible gene regulation.
Asunto(s)
Carcinoma Hepatocelular/genética , Regulación Neoplásica de la Expresión Génica , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Hipoxia/fisiopatología , Neuroblastoma/genética , Nucleosomas/fisiología , Regiones Promotoras Genéticas , Biomarcadores de Tumor/genética , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patología , Ensamble y Desensamble de Cromatina , Perfilación de la Expresión Génica , Humanos , Subunidad alfa del Factor 1 Inducible por Hipoxia/genética , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patología , Neuroblastoma/metabolismo , Neuroblastoma/patología , Células Tumorales CultivadasRESUMEN
Cytotoxic T cells infiltrating tumors are thought to utilize HIF transcription factors during adaptation to the hypoxic tumor microenvironment. Deletion analyses of the two key HIF isoforms found that HIF-1α, but not HIF-2α, was essential for the effector state in CD8+ T cells. Furthermore, loss of HIF-1α in CD8+ T cells reduced tumor infiltration and tumor cell killing, and altered tumor vascularization. Deletion of VEGF-A, an HIF target gene, in CD8+ T cells accelerated tumorigenesis while also altering vascularization. Analyses of human breast cancer showed inverse correlations between VEGF-A expression and CD8+ T cell infiltration, and a link between T cell infiltration and vascularization. These data demonstrate that the HIF-1α/VEGF-A axis is an essential aspect of tumor immunity.