Understanding the molecular underpinnings of cancer is of critical importance to developing targeted intervention strategies. Identification of such targets, however, is notoriously difficult and unpredictable. Malignant cell transformation requires the cooperation of a few oncogenic mutations that cause substantial reorganization of many cell features and induce complex changes in gene expression patterns. Genes critical to this multi-faceted cellular phenotype thus only have been identified following signaling pathway analysis or on an ad hoc basis. Our observations that cell transformation by cooperating oncogenic lesions depends on synergistic modulation of downstream signaling circuitry suggest that malignant transformation is a highly cooperative process, involving synergy at multiple levels of regulation, including gene expression. Here we show that a large proportion of genes controlled synergistically by loss-of-function p53 and Ras activation are critical to the malignant state. Remarkably, 14 among 24 such 'cooperation response genes' (CRGs) were found to contribute to tumor formation in gene perturbation experiments. In contrast, only one in 14 perturbations of genes responding in a non-synergistic manner had a similar effect. Synergistic control of gene expression by oncogenic mutations thus emerges as an underlying key to malignancy and provides an attractive rationale for identifying intervention targets in gene networks downstream of oncogenic gain and loss-of-function mutations.
Synergistic response to oncogenic mutations defines gene class critical to cancer phenotype.
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View SamplesMouse CD8+ T cells affected by ID3 (Inhibitor of DNA binding 3) display patterns of gene expression suggesting enhanced persistance and survival. In this study, we identified genes differentially expressed between ID32a transduced and mock transduced, and ID32a knockout and wild type mouse CD8+ T cells. Most prominent functions of differentially expressed genes include DNA replication-associated repair, maintenance of chromosome stability and mitotic cell divison machinery. Overall, these data suggest that ID3 acts in favor of maintained survival in CD8+ mouse T cells.
Repression of the DNA-binding inhibitor Id3 by Blimp-1 limits the formation of memory CD8+ T cells.
Treatment
View SamplesLong-lived, self-renewing, multipotent T memory stem cells (TSCM) can trigger profound and sustained tumor regression but their rareness poses a major hurdle to their clinical application. Presently, clinically compliant procedures to generate relevant numbers of this T cell population are undefined. Here, we provide a strategy for deriving large numbers of clinical grade tumor-redirected TSCM cells starting from nave precursors. CD8+CD62L+CD45RA+ nave T cells enriched by streptamer-based serial positive selection were activated by CD3/CD28 engagement in the presence of IL-7, IL-21 and the glycogen synthase-3 inhibitor TWS119, and genetically engineered to express a CD19-specific chimeric antigen receptor (CD19-CAR). These conditions allowed for the generation of CD19-CAR modified TSCM cells that were phenotypically, functionally and transcriptomically equivalent to their naturally occurring counterpart. Compared with T cell products currently under clinical investigation, CD19-CAR modified TSCM cells exhibit enhanced metabolic fitness, persistence and anti-tumor activity against systemic acute lymphoblastic leukemia xenografts. Based on these findings, we have initiated a phase 1 clinical study to evaluate the activity of CD19-CAR modified TSCM in patients with B-cell malignancies refractory to prior allogeneic hematopoietic stem cell transplantation.
Generation of clinical-grade CD19-specific CAR-modified CD8+ memory stem cells for the treatment of human B-cell malignancies.
Subject
View SamplesCancer cells must evade immune responses at distant sites to establish metastases. The lung is a frequent site for metastasis. We hypothesized that lung-specific immunoregulatory mechanisms create an immunologically permissive environment for tumor colonization. We found that T cell-intrinsic expression of the oxygen-sensing prolyl-hydroxylase (PHD) proteins is required to maintain local tolerance against innocuous antigens in the lung, but powerfully licenses colonization by circulating tumor cells. PHD proteins limit pulmonary type helper (Th)-1 responses, promote CD4+-regulatory T (Treg) cell induction, and restrain CD8+ T cell effector function. Tumor colonization is accompanied by PHD protein-dependent induction of pulmonary Treg cells and suppression of IFN-g-dependent tumor clearance. T cell-intrinsic deletion or pharmacological inhibition of PHD proteins limits tumor colonization of the lung and improves the efficacy of adoptive cell transfer immunotherapy. Collectively, PHD proteins function in T cells to coordinate distinct immunoregulatory programs within the lung that are permissive to cancer metastasis. Overall design: RNA expression was measured by RNA-Seq at day 4 following stimulation of naïve FACS-sorted CD4+ T cells with anti-CD3 and anti-CD28 antibodies in the presence of indicated doses of TGF-b. Gene expression was analysed separately in control Cd4Cre (WT) and Egln1fl/fl Egln2fl/fl Egln3fl/fl Cd4Cre (tKO) cells, or in cells treated with the pharmacological PHD inhibitor dimethyloxaloylglycine (DMOG) and control vehicle-treated cells.
Oxygen Sensing by T Cells Establishes an Immunologically Tolerant Metastatic Niche.
Specimen part, Treatment, Subject
View SamplesTo better elucidate epigenetic mechanisms that correlate with the dynamic gene expression program observed after T cell activation, we investigated the genomic landscape of histone modifications in antigen-experienced CD8+ T cells. Using a ChIP-Seq approach coupled with global gene expression profiling, we generated genome-wide histone H3 lysine 4 (H3K4me3) and H3 lysine 27 (H3K27me3) trimethylation maps in distinct subsets of CD8+ T cells-nave, stem cell memory, central memory, and effector memory-to gain insight into how histone architecture is remodeled during the differentiation of activated T cells. We show that H3K4me3 histone modifications are associated with activation of genes, while H3K27me3 is negatively correlated with gene expression at canonical loci and enhancers regions associated with T cell metabolism, effector function, and memory. Our results also reveal histone modifications and gene expression signatures that distinguish the recently identified stem cell memory T cell from other antigen-experienced CD8+ T cell subsets. Taken together, our results suggest that antigen-experienced T cells may undergo chromatin remodeling in a progressive fashion that may have implications for our understanding of peripheral T cell ontogeny and the formation of immunological memory.
Lineage relationship of CD8(+) T cell subsets is revealed by progressive changes in the epigenetic landscape.
Specimen part
View SamplesAdoptive immunotherapies using genetically-redirected T cells expressing a chimeric antigen receptor (CAR) or T cell receptor (TCR) are poised to enter mainstream clinical practice. Despite encouraging results, some patients fail to respond to current therapies. In part, this phenomenon has been associated with infusion of a reduced number of early memory T cells. Herein, we report that pharmacologic disruption of AKT-signaling (AKTi) is compatible with the transduction of both CARs and TCRs into human T cells and promotes a minimally differentiated CD62L-expressing phenotype. Critically, this intervention did not compromise cell yield. Mechanistically, disruption of AKT-signaling preserved MAPK activation and promoted the intra-nuclear accumulation of FOXO1, a key transcriptional regulator of T-cell memory. Consequently, AKTi synchronized the T-cell transcriptional profile for FOXO1-dependent target genes across multiple donors. Expression of an AKT-resistant FOXO1 mutant phenocopied the influence of AKTi while addition of AKTi to T cells expressing mutant FOXO1 failed to further augment the frequency of CD62L-expressing cells. Finally, CD19 CAR-modified T cells transduced and expanded in AKTi treated established B-cell acute lymphoblastic leukemia superiorly to conventionally grown T cells in a murine xenograft model. Thus, inhibition of AKT-signaling represents a generalizable strategy to generate large numbers of receptor-modified T cells with an early memory phenotype.
Inhibition of AKT signaling uncouples T cell differentiation from expansion for receptor-engineered adoptive immunotherapy.
Treatment, Subject, Time
View SamplesTumours 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. Overall design: 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.
Ionic immune suppression within the tumour microenvironment limits T cell effector function.
Sex, Age, Specimen part, Cell line, Treatment, Subject
View SamplesSerial comparison between Th1 and Th17 tumor-specific cells cultured in vitro and ex vivo after transferred into sublethaly irradiated B6.PL mice. Th17-derived cells acquire Th1-like properties in vivo but maintain a distinct molecular profile.
Th17 cells are long lived and retain a stem cell-like molecular signature.
Specimen part, Treatment
View SamplesT cell receptor (TCR) signaling is a critical process in immunity to infectious disease and cancer. Recently, a genome-wide association study has implicated polymorphisms in the CISH locus with susceptibility to infectious diseases. However, the role of Cish in the immune responses and its molecular underpinnings remains unclear. Here we demonstrate that Cish deletion resulted in protection against viral infection and enhanced CD8+ T cell tumor immunity. Transcriptome profiling revealed a hyper-TCR activation signature in Cish-deficient CD8+ T cells. Subsequent analysis revealed an inhibitory role for Cish in PLC1 activation, ensuing Ca2+ release and downstream signaling. In the steady-state Cish was found to physically interact with PLC1, however, PLC1 was only found to be ubiquitinated after acute TCR stimulation in the presence of Cish. These data implicate Cish as a potent negative regulator of TCR signaling and T cell immunity to infection and cancer and may have significant clinical applications.
Cish actively silences TCR signaling in CD8+ T cells to maintain tumor tolerance.
Specimen part, Treatment
View SamplesThrough a diversity of functional lineages, cells of the innate and adaptive immune system either drive or constrain immune reactions within tumors. Thus, while the immune system has a powerful ability to recognize and kill cancer cells, this function is often suppressed preventing clearance of disease. The transcription factor (TF) BACH2 controls the differentiation and function of multiple innate and adaptive immune lineages, but its role in regulating tumor immunity is not known. Here, we demonstrate that BACH2 is required to establish immunosuppression within tumors. We found that growth of subcutaneously implanted tumors was markedly impaired in Bach2-deficient mice and coincided with intratumoral activation of both innate and adaptive immunity but was dependent upon adaptive immunity. Analysis of tumor-infiltrating lymphocytes in Bach2-deficient mice revealed high frequencies of CD4+ and CD8+ effector cells expressing the inflammatory cytokine IFN-. Lymphocyte activation coincided with reduction in the frequency of intratumoral CD4+ Foxp3+ regulatory T (Treg) cells. Mechanistically, Treg-dependent inhibition of CD8+ T cells was required for BACH2-mediated tumor immunosuppression. These findings demonstrate that BACH2 is a key component of the molecular programme of tumor immunosuppression and identify a new target for development of therapies aimed at reversing immunosuppression in cancer.
The transcription factor BACH2 promotes tumor immunosuppression.
Specimen part
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