Project description:Tumours progress despite being infiltrated by effector T cells. Tumour necrosis is associated with poor survival in a variety of cancers. Here, we report that that necrosis causes release of an intracellular ion, potassium, into the extracellular fluid of human and mouse tumours. Surprisingly, elevated extracellular potassium ([K+]e) was sufficient to profoundly suppress mouse and human T cell anti-tumour function. Elevations in [K+]e acted to acutely impair T cell receptor (TCR) dependent Akt-mTOR phosphorylation and effector function. Potassium mediated suppression of Akt-mTOR signalling and T cell effector function required intact activity of PP2A, a serine/threonine phosphatase. The suppressive effect mediated by elevated [K+]e required a T cell-intrinsic increase in intracellular potassium ([K+]i) and was independent of changes in plasma membrane potential (Vm). Finally, ionic reprogramming of tumour-specific T cells via over-expression of the voltage-gated potassium channel Kv1.3 lowered [K+]i and improved effector functions in vitro and in vivo, with this gain of function being dependent on intact channel function. Consequently, Kv1.3 T cell expression enhanced tumour clearance and the survival of melanoma-bearing mice. These results uncover a previously undescribed ionic checkpoint against T cell function within tumours and identify new strategies for cancer immunotherapy. RNA expression was measured by RNA-Seq on day 5 of cultures, maintained in individual biologial triplicates which were stimulated with immobilized anti-CD3/28 antibodies or kept in complete media (no stim) - with equivalent conditions treated with isotonic media containing elevated potassium.
Project description:Tumours progress despite being infiltrated by effector T cells. Tumour necrosis is associated with poor survival in a variety of cancers. Here, we report that that necrosis causes release of an intracellular ion, potassium, into the extracellular fluid of human and mouse tumours. Surprisingly, elevated extracellular potassium ([K+]e) was sufficient to profoundly suppress mouse and human T cell anti-tumour function. Elevations in [K+]e acted to acutely impair T cell receptor (TCR) dependent Akt-mTOR phosphorylation and effector function. Potassium mediated suppression of Akt-mTOR signalling and T cell effector function required intact activity of PP2A, a serine/threonine phosphatase. The suppressive effect mediated by elevated [K+]e required a T cell-intrinsic increase in intracellular potassium ([K+]i) and was independent of changes in plasma membrane potential (Vm). Finally, ionic reprogramming of tumour-specific T cells via over-expression of the voltage-gated potassium channel Kv1.3 lowered [K+]i and improved effector functions in vitro and in vivo, with this gain of function being dependent on intact channel function. Consequently, Kv1.3 T cell expression enhanced tumour clearance and the survival of melanoma-bearing mice. These results uncover a previously undescribed ionic checkpoint against T cell function within tumours and identify new strategies for cancer immunotherapy.
Project description:Tumour-associated macrophages (TAMs), as one of the most abundant and phagocytic tumour-infiltrating immune cells, play a pivotal role in tumour antigen clearance and immune suppression. M2-like TAMs present a heightened lysosomal acidity and protease activity, which limits the function of antigen cross-presentation. How to selectively reprogram the antigen-destroying TAMs to a restorative phenotype for efficient anti-tumour immunity is challenging. Here, we report a pH-gated nanoadjuvant (PGN) that selectively targets the lysosomes of M2-like TAMs in tumours rather than the corresponding organelles from macrophages in healthy tissues. Enabled by the PGN nanotechnology, M2-like TAMs are specifically switched to M1-like phenotypes with tuned-down lysosomal function featured by attenuated lysosomal acidity and cathepsin activity for improved antigen cross-presentation, thus provoking adaptive immune response and sustained tumour regression. Our findings provide new insights into how to specifically regulate lysosomal function of TAMs for efficient cancer immunotherapy.
Project description:Development of a vaccine formula that alters the tumour-infiltrating lymphocytes to be more immune active against a tumour is key to the improvement of clinical responses to immunotherapy. Here, we demonstrate that, in conjunction with E7 antigen specific immunotherapy, and IL-10 and PD-1 blockade, intra-tumoral administration of caerin 1.1 and 1.9 peptides further improves the tumour microenvironment (TME) when compared with injection of a control peptide. We used single cell transcriptomics and mass spectrometry-based proteomics to quantify changes in cellular activity across different cell types within the TME. We show that the injection of caerin 1.1/1.9 increases immune activating macrophages and NK cells, while reducing immunosuppressive macrophages with M2 phenotype, and increased numbers of activated CD8+ T cells with higher populations of memory and effector-memory CD8+ T subsets. Proteomic profiling demonstrated activation of Stat1 modulated apoptosis and production of nitric oxide. Further, computational integration of the proteome with the single cell transcriptome was consistent with deactivation of immune suppressive B cell function following caerin 1.1 and 1.9 treatment.
Project description:<p>Neoantigens, which are derived from tumour-specific protein-coding mutations, are exempt from central tolerance, can generate robust immune responses and can function as bona fide antigens that facilitate tumour rejection. We demonstrated that a strategy that uses multi-epitope, personalized neoantigen vaccination, which has previously been tested in patients with high-risk melanoma, is feasible for tumours such as glioblastoma, which typically have a relatively low mutation load and an immunologically ‘cold’ tumour microenvironment. Here we conducted whole-exome sequencing of tumor and normal cells from individual patients with glioblastoma to identify tumor-specific mutations. We assessed the expression of mutated alleles by RNA-sequencing of tumor. We used personalized neoantigen-targeting vaccines to immunize patients newly diagnosed with glioblastoma following surgical resection and conventional radiotherapy in a phase I/Ib study. Patients who did not receive dexamethasone-a highly potent corticosteroid that is frequently prescribed to treat cerebral oedema in patients with glioblastoma-generated circulating polyfunctional neoantigen-specific CD4+ and CD8+ T cell responses that were enriched in a memory phenotype and showed an increase in the number of tumour-infiltrating T cells. Using single-cell T cell receptor analysis, we provide evidence that neoantigen-specific T cells from the peripheral blood can migrate into an intracranial glioblastoma tumour. Neoantigen-targeting vaccines thus have the potential to favourably alter the immune milieu of glioblastoma.</p>
Project description:We performed spatial transcriptome profiling (ST-seq) on nine fresh frozen tissue sections to understand the immunophenotypes; immune cell types, states and their spatial location within the clear cell renal cell carcinoma (ccRCC) tumour microenvironment (TME).
Project description:Type I Interferons (IFN-I) stimulate pro-inflammatory programs critical for immune activation, but also induce immune-suppressive feedback circuits that contribute to the failure of cancer control. Yet, how IFN-Is differentially induce these opposing programs remains enigmatic. We establish that the transcription factor Interferon Regulatory Factor 2 (IRF2) is a central feedback molecule attenuating IFN signaling and driving CD8 T cell exhaustion in the tumor microenvironment. IRF2 inhibits CD8 T cell effector function in response to sustained interferon signaling by programming T cell exhaustion. Lineage-specific deletion of IRF2 limits CD8 T cells exhaustion to maintain effector functions, thereby enabling long-term tumor control, and increased responsiveness to immune-checkpoint and adoptive cell therapies. Long-term tumor control by IRF2-deficient CD8 T cells is dependent on continuous integration of both IFN-I and IFN? signals, which in the absence of IRF2, potentiate sustained effector function instead of exhaustion. Thus, IRF2 redirects IFN signalling to drive T cell exhaustion and prevent tumor control.
Project description:Tumour suppression by immune system through stochastic oscillations
GiulioCaravagnaa
Albertod’Onofriob
PaoloMilazzoa
RobertoBarbutia
https://doi.org/10.1016/j.jtbi.2010.05.013
Abstract
The well-known Kirschner–Panetta model for tumour–immune System interplay [Kirschner, D., Panetta, J.C., 1998. Modelling immunotherapy of the tumour–immune interaction. J. Math. Biol. 37 (3), 235–252] reproduces a number of features of this essential interaction, but it excludes the possibility of tumour suppression by the immune system in the absence of therapy. Here we present a hybrid–stochastic version of that model. In this new framework, we show that in reality the model is also able to reproduce the suppression, through stochastic extinction after the first spike of an oscillation.
Project description:Through their functional diversification, CD4+ T cells play key roles in both driving and constraining immune-mediated pathology. Transcription factors are critical in the generation and maintenance of cellular diversity and negative regulators antagonistic to alternate fates often act in conjunction with positive regulators to stabilize lineage specification1. Polymorphisms within the locus encoding a transcription factor BACH2 are associated with diverse immune-mediated diseases including asthma2, multiple sclerosis3, Crohn¹s disease4-5, coeliac disease6, vitiligo7 and type 1 diabetes8. A role for Bach2 in maintaining immune homeostasis, however, has not been established. Here, we define Bach2 as a broad regulator of immune activation that stabilizes immunoregulatory capacity while repressing the differentiation programmes of multiple effector lineages in CD4+ T cells. Bach2 was required for efficient formation of regulatory (Treg) cells and consequently for suppression of lethal inflammation in a manner that was Treg cell dependent. Assessment of the genome-wide function of Bach2, however, revealed that it represses genes associated with effector cell differentiation. Consequently, its absence during Treg polarization resulted in inappropriate diversion to effector lineages. In addition, Bach2 constrained full effector differentiation within Th1, Th2 and Th17 cell lineages. These findings identify Bach2 as a key regulator of CD4+ T-cell differentiation that prevents inflammatory disease by controlling the balance between tolerance and immunity. The role of Bach2t to regulate immune homeostasis was investigated by mapping DNA binding profiles of Bach2 in iTreg condition. The function of Bach2 was also evaluated by comparing transcriptome in WT and Bach2-deficient iTreg cells and further comparison was done with transcriptome in naive, Th1, Th2, and Th17 conditions.