scholarly journals 622 Disrupted oxygen supply and tumor hyper- oxygen consumption contribute independently to prostate cancer immune privilege

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A652-A652
Author(s):  
Priyamvada Jayaprakash ◽  
Meghan Rice ◽  
Krithikaa Rajkumar Bhanu ◽  
Brittany Morrow ◽  
Joseph Marszalek ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
T Cells ◽  
T Cell ◽  
Oxidative Metabolism ◽  
Complex I ◽  
Tumor Regression ◽  
Tumor Hypoxia ◽  
Checkpoint Blockade ◽  
Mitochondrial Complex I ◽  
Mitochondrial Complex

BackgroundDespite the success of immunotherapy in immune-infiltrated ”hot” tumors like melanoma, ”cold” tumors like prostate cancer remain unresponsive [1,2,3]. We find that these tumors harbor regions of hypoxia that act as islands of immune privilege that exclude T cells, while retaining immunosuppressive myeloid cells. Targeting hypoxia using the hypoxia-activated prodrug, TH-302 (Evofosfamide) reduced hypoxic regions and co-operated with immune checkpoint blockade (anti-CTLA-4+anti PD-1) to drive tumor regression in transplantable and spontaneous murine prostate tumors [4]. In a Phase I clinical trial, the combination of Evofosfamide and anti CTLA-4 (Ipilimumab) elicited both objective responses and prolonged disease stabilization in late-stage ”cold” tumor patients. However, Evofosfamide reduces but does not eliminate hypoxia and patient tumors resistant to treatment with Evofosfamide and Ipilimumab were hyper-metabolic [5]. Heightened tumor oxidative metabolism has been shown to generate hypoxic zones that resist PD-1 blockade therapy [6] and treatment with Metformin, a mitochondrial complex I inhibitor may reduce hypoxia and improve responses [7]. We hypothesized that targeting tumor oxidative metabolism using mitochondrial complex I inhibitors might diminish tumor hypoxia and, in conjunction with Evofosfamide, sensitize unresponsive tumors to immunotherapy.MethodsWe investigated the capacity of two mitochondrial complex I inhibitors to reduce tumor oxidative metabolism, diminish myeloid suppressive capacity and improve anti-tumor T cell immunity, alone and in combination with Evofosfamide and checkpoint blockade. We assessed tumor burden and immune composition and characterized metabolic profiles using Seahorse XFe96 analyzer (Agilent).ResultsWhile Evofosfamide or inhibition of oxidative metabolism alone did not significantly impact tumor regression, dual combination and triple combination with checkpoint blockade led to a significant reduction in tumor burden. Assessment of the tumor immune microenvironment identified improvements in CD8 and CD4 effector T cell proliferation. In vitro metabolic and functional profiling of TRAMP-C2 prostate tumors, pre-activated T cells and myeloid derived suppressor cells revealed differential effects of complex I inhibition, with inhibition resulting in reduced tumor proliferation and myeloid suppressive function but increases in proliferation and cytotoxic function of pre-activated T cells.ConclusionsOur findings indicate that tumor hypoxia and associated immune suppressive programming can be reduced through both local tissue remodeling and limitation of tumor oxygen metabolism. Complex I inhibition selectively inhibits tumor and myeloid cell function, while sparing T cells. This provides opportunities to craft synergistic immuno-metabolic therapies with the potential to treat ”cold” tumor patients refractory to current FDA approved immunotherapeutics.ReferencesCurran MA, Montalvo W, Yagita H, and Allison JP. PD-1 and CTLA-4 combination blockade expands infiltrating T cells and reduces regulatory T and myeloid cells within B16 melanoma tumors. Proc Natl Acad Sci U S A. 2010; 107(9): 4275–80.Wolchok JD, Kluger H, Callahan MK, Postow MA, Rizvi NA, Lesokhin AM, et al. Nivolumab plus ipilimumab in advanced melanoma. N Engl J Med. 2013; 369(2): 122–33.Kwon ED, Drake CG, Scher HI, Fizazi K, Bossi A, van den Eertwegh AJ, et al. Ipilimumab versus placebo after radiotherapy in patients with metastatic castration-resistant prostate cancer that had progressed after docetaxel chemotherapy (CA184-043): a multicentre, randomised, doubleblind, phase 3 trial. Lancet Oncol. 2014;15(7):700–12.Jayaprakash P, Ai M, Liu A, Budhani P, Bartkowiak T, Sheng J, et al. Targeted hypoxia reduction restores T cell infiltration and sensitizes prostate cancer to immunotherapy. J Clin Invest. 2018; 128 (11): 5137–5149.Hegde A, Jayaprakash P, Couillault CA, Piha-Paul S, Karp D, Rodon J, et al. A Phase I Dose-Escalation Study to Evaluate the Safety and Tolerability of Evofosfamide in Combination with Ipilimumab in Advanced Solid Malignancies. Clin Cancer Res. 2021; 27(11): 3050–3060.Najjar YG, Menk AV, Sander C, Rao U, Karunamurthy A, Bhatia R, et al. Tumor cell oxidative metabolism as a barrier to PD-1 blockade immunotherapy in melanoma. JCI Insight. 2019 4(5): e124989. A.Scharping NE, Menk AV, Whetstone RD, Zeng X, Delgoffe GM. Efficacy of PD-1 Blockade Is Potentiated by Metformin-Induced Reduction of Tumor Hypoxia. Cancer Immunol Res. 2017; 5(1):9–16.

Mitochondrial complex I gene mutations drive metabolic reprogramming in prostate cancer

2019 ◽  
Vol 18 (8) ◽  
pp. e3041
Author(s):  
B. Schöpf ◽  
H. Weissensteiner ◽  
G. Schäfer ◽  
A. Naschberger ◽  
B. Rupp ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Complex I ◽  
Gene Mutations ◽  
Metabolic Reprogramming ◽  
Mitochondrial Complex I ◽  
Mitochondrial Complex ◽  
I Gene

Prostate Cancer Immunology: Biology, Therapeutics, and Challenges

2005 ◽  
Vol 23 (32) ◽  
pp. 8262-8269 ◽  
Author(s):  
W. Scott Webster ◽  
Eric J. Small ◽  
Brian I. Rini ◽  
Eugene D. Kwon
Keyword(s):  
Prostate Cancer ◽  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Advanced Prostate Cancer ◽  
Cell Activation ◽  
Tumor Regression ◽  
Prostate Cancer Treatment ◽  
Mechanistic Basis ◽  
Antigen Presenting

A number of recently developed and promising approaches to antitumoral immunotherapy are being investigated as potential treatments for advanced prostate cancer. These approaches largely revolve around strategies to increase antigen-specific T-cell activation against prostate tumors as well as precise manipulations of critical co-regulatory receptors that help to maintain and prolong the activity of antigen-presenting cells and T cells that are capable of mediating tumor regression. Herein, we describe the experience with the most recent and promising approaches pertaining to prostate cancer immunotherapy. Additionally, we discuss the mechanistic basis for these approaches as well as current limitations that must still be addressed in order to propel immunotherapy into the forefront of prostate cancer treatment.

scholarly journals Platelet Mitochondrial Complex I and I+III Activities Do Not Correlate with Cerebral Mitochondrial Oxidative Metabolism

2010 ◽  
Vol 31 (1) ◽  
pp. e1-e5 ◽  
Author(s):  
William J Powers ◽  
Richard H Haas ◽  
Thuy Le ◽  
Tom O Videen ◽  
Joanne Markham ◽  
...  
Keyword(s):  
Metabolic Rate ◽  
Oxidative Metabolism ◽  
Complex I ◽  
Mitochondrial Metabolism ◽  
Mitochondrial Complex I ◽  
Mitochondrial Complex ◽  
Ets Activity ◽  
Cerebral Metabolic Rate ◽  
Glucose Ratio ◽  
Mitochondrial Oxidative Metabolism

Assays of mitochondrial electron transport system (ETS) activity in circulating blood platelets have been used to investigate the cause of neurodegenerative diseases. However, the correspondence between platelet ETS function and cerebral mitochondrial metabolism is not well characterized. To assess the validity of using platelet ETS activity to infer cerebral mitochondrial metabolism, we measured platelet ETS activity (complex I and complex I+III), cerebral metabolic rate of oxygen (CMRO2), and the CMRO2/cerebral metabolic rate for glucose ratio in 40 subjects: 7 with never-medicated Parkinson's disease, 13 with genetically proved Huntington's disease, and 20 normal controls. We found no correlation between in vivo measures of cerebral mitochondrial oxidative metabolism and ex vivo assays of platelet complex I and complex I+III activity performed on blood collected immediately before cerebral metabolism studies. We saw no evidence of a threshold effect when comparing platelet complex I and complex I+III activity with cerebral oxidative metabolism across a 4- to 10-fold range of platelet ETS activity. On the basis of these data, we conclude that measures of mitochondrial complex I and I+III activity in platelets within the ranges we have studied do not correlate with oxidative function of cerebral mitochondria.

512 Terminally exhausted CD8+ T cells potentiate the tolerogenic tumor microenvironment as functional suppressors

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A548-A548
Author(s):  
Paolo Vignali ◽  
Kristin DePeaux ◽  
McLane Watson ◽  
Ashley Menk ◽  
Nicole Scharping ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Oxidative Metabolism ◽  
Advanced Melanoma ◽  
Effector T Cells ◽  
Checkpoint Blockade ◽  
Tumor Control ◽  
List Type ◽  
Murine Melanoma

BackgroundBlockade of co-inhibitory ‘checkpoint’ molecules, PD-1 and CTLA-4, has induced impressive clinical responses in advanced tumors; yet only in a subset of patients.1–3 Limited success with checkpoint blockade therapy suggests other cell extrinsic or intrinsic mechanisms may be dampening an effective immune response. Cytotoxic CD8+ T cells (CTL) encountering chronic antigen and metabolic restriction can differentiate to a terminally exhausted state (Texh), marked by hyporesponsiveness and metabolic, epigenetic, and transcriptional dysfunction.4–8 While enrichment of this population in tumor is a negative prognostic factor,9–10 it remains unclear whether Texh are simply non-functional or instead possess tolerogenic or suppressive properties. Transcriptional profiling of tumor-infiltrating PD-1int (progenitor exhausted) CTL versus PD-1hiTIM-3+ (terminally exhausted; Texh), reveals that exhausted cells express a pattern of genes associated with immune suppression. We hypothesize that Texh potentiate the suppressive microenvironment of solid tumor by autoregulation and inhibition of local immune responses.MethodsT cell populations were isolated from murine melanoma–B16-F10 or a lab-generated melanoma clone of the spontaneous BREF/PTEN model–by expression of inhibitory receptors and assayed in tandem in microsuppression assays. Murine melanoma clones with inhibited oxidative metabolism were generated by CRISPR-Cas9 deletion and validated for ablated mitochondrial respiration by extracellular flux analysis. Enforced expression of CD39 in effector T cells was attained by murine retroviral vector delivery.ResultsWhen sorted directly from tumor, PD-1hiTim3+ Texh, but not progenitor exhausted PD-1int CTL, induce marked suppression of T cell effector responses, comparable to Foxp3+ Treg from the same environment. Expression of the ectonucleotidase, CD39, is uniquely expressed in Texh and increases as T cells differentiate towards exhaustion. Genetic deletion of CD39 in Texh eliminates the regulatory phenotype of tumor-infiltrating Texh and enforced CD39 expression on effector T cells can inhibit T cell receptor signaling and downstream function. CD39 expression correlates with exposure to hypoxia and Texh sorted from tumors engineered to be less hypoxic displayed a significant loss of suppressive capacity. Our data suggest that tumor hypoxia enforces Hif1a-dependent expression of CD39 which depletes extracellular ATP, contributes to generation of immunosuppressive adenosine, and has been previously associated with terminal exhaustion.11–13ConclusionsOur data support a model that as CTL progress to terminal exhaustion, hypoxic exposure enforces the upregulation of CD39, providing Texh a mechanism to suppress proinflammatory processes. These findings suggest Texh are not solely dysfunctional but rather are deleterious to anti-tumor immunity and may need to be drastically reprogrammed or deleted in order to alleviate immunosuppressive functions.ReferencesWolchok JD. et al. Overall survival with combined nivolumab and ipilimumab in advanced melanoma. N. Engl. J. Med 2017; 377, 1345–1356.Hellmann MD, et al. Nivolumab plus ipilimumab as first-line treatment for advanced non-small-cell lung cancer (CheckMate 012): results of an open-label, phase 1, multicohort study. Lancet Oncol 2017; 18, 31–41.Robert C. et al. Pembrolizumab versus ipilimumab in advanced melanoma. N. Engl. J. Med. 2015; 372, 2521–2532.Miller BC, et al. Subsets of exhausted CD8+ T cells differentially mediate tumor control and respond to checkpoint blockade. Nat. Immunol 2019;20:326–336.Im SJ, et al. Defining CD8+ T cells that provide the proliferative burst after PD-1 therapy. Nature 2016;537:417–421.Blackburn SD, Shin H, Freeman GJ & Wherry EJ. Selective expansion of a subset of exhausted CD8 T cells by alphaPD-L1 blockade. Proc. Natl. Acad. Sci 2008;105:15016–15021.Pauken KE, et al. Epigenetic stability of exhausted T cells limits durability of reinvigoration by PD-1 blockade. Science 2016;354:1160–1165.Najjar YG, et al. Tumor cell oxidative metabolism as a barrier to PD-1 blockade immunotherapy in melanoma. JCI Insight. 2019; 4.Loo K, et al. Partially exhausted tumor-infiltrating lymphocytes predict response to combination immunotherapy. JCI Insight 2017; 2.Daud AI, et al. Tumor immune profiling predicts response to anti-PD-1 therapy in human melanoma. J. Clin. Invest 2016;126:3447–3452.. Duhen T, et al. Co-expression of CD39 and CD103 identifies tumor-reactive CD8 T cells in human solid tumors. Nat. Commun 2018;9:2724.Canale FP, et al. CD39 Expression defines cell exhaustion in tumor-infiltrating CD8+ T Cells. Cancer Res 2018;78:115–128.Gupta PK, et al. CD39 expression identifies terminally exhausted CD8+ T cells. PLoS Pathog 2015;11, e1005177.

scholarly journals 679 Tumor hypoxia drives suppressor function in exhausted T cells limiting antitumor immunity

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A707-A707
Author(s):  
Paolo Vignali ◽  
Kristin DePeaux ◽  
McLane Watson ◽  
Nicole Scharping ◽  
Ashley Menk ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Tumor Hypoxia ◽  
Cd8 T Cell ◽  
Treg Cells ◽  
Checkpoint Blockade ◽  
Tumor Control ◽  
Cell Exhaustion ◽  
Hypoxia Exposure

BackgroundWhile CD8+ cytotoxic T cells are clearly critical for identification and elimination of cancer cells, factors concentrated within the tumor microenvironment drive altered differentiation of these cells to a hypofunctional, short-lived state termed T cell exhaustion1 (figure 1a). Exhaustion is a progressive lineage, and it is now clear that terminally exhausted T (tTexh) cells are not the targets of checkpoint blockade immunotherapy but may serve as factors that limit immunotherapeutic efficacy.2–6 Compared directly, tumor-infiltrating CD8+ tTexh cells bear notable phenotypic similarity to CD4+Foxp3+ regulatory T (Treg) cells in expression of immunosuppressive molecules suggesting beyond loss of effector function, tTexh cells may be directly anti-functional and constrain tumor-specific immunity. Thus, we hypothesize that tTexh cells potentiate the suppressive microenvironment of solid tumor and that strategies to limit their generation or reprogram their immunosuppressive nature will improve control of tumor progression.MethodsT cell populations were isolated from murine tumor lines, B16-F10 melanoma, Ptenflox/floxBrafLSL.V600ETyr2Cre.ERT2–derived Clone 24 melanoma, MEER head and neck carcinoma, and MC38 adenocarcinoma. T cell-specific CD39 (Entpd1) deletion was accomplished by crossing Entpd1flox/flox mice to Cd4Cre or E8iGFP-Cre-ERT2. Enforced expression of CD39 in effector T cells was attained by murine retroviral vector delivery. Tumor hypoxia was alleviated by CRISPR-Cas9-directed deletion of mitochondrial genes in B16-F10 or by treatment with axitinib or metformin.ResultsWhen sorted directly from tumor, CD8+PD-1hiTim-3+ tTexh cells, but not progenitor PD-1intTim-3– pTexh cells, induce marked suppression of T cell effector responses, comparable to CD4+Foxp3+ Treg cells from the same environment (figure 1b-c). The ectonucleotidase, CD39, increases as cells progressively differentiate and is associated with terminal exhaustion.7 8 CD8+ T cell-restricted deletion of CD39 restricts regulatory functions of tTexh cells (figure 1b), improving tumor control and augmenting response to checkpoint blockade (figure 1d). CD39 expression correlates with hypoxia exposure and tTexh cells sorted from tumors engineered to be less hypoxic or treated with hypoxia-mitigating agents displayed a significant loss of suppressive capacity. Our data suggest that tumor hypoxia enforces Hif1a-dependent expression of CD39 which depletes extracellular ATP, supports adenosine generation, and limits therapeutic efficacy.ConclusionsOur data support a model that as CD8+ T cells progress to terminal exhaustion, hypoxia exposure enforces the upregulation of CD39, providing tTexh cells a mechanism to suppress proinflammatory processes and promote tumor progression. These findings suggest tTexh cells are not solely dysfunctional but rather are deleterious to antitumor immunity and may need to be drastically reprogrammed or depleted to improve patient outcomes.ReferencesBlank CU, et al. Defining “T cell exhaustion”. Nat Rev Immunol 2019;19:665–674.Miller BC, et al. Subsets of exhausted CD8+ T cells differentially mediate tumor control and respond to checkpoint blockade. Nat Immunol 2019;20:326–336.Blackburn SD, et al. Selective expansion of a subset of exhausted CD8 T cells by alphaPD-L1 blockade. Proc Natl Acad Sci USA 2008;105:15016–15021.Sade-Feldman M, et al. Defining T Cell states associated with response to checkpoint immunotherapy in Melanoma. Cell 2018;175:998–1013.e20.Im SJ, et al. Defining CD8+ T cells that provide the proliferative burst after PD-1 therapy. Nature 2016;537:417–421.Siddiqui I, et al. Intratumoral Tcf1+PD-1+CD8+ T Cells with stem-like properties promote tumor control in response to vaccination and checkpoint blockade immunotherapy. Immunity 2019;50:195–211.e10.Canale FP, et al. CD39 expression defines cell exhaustion in tumor-infiltrating CD8+ T Cells. Cancer Res 2018;78:115–128.Gupta PK, et al. CD39 expression identifies terminally exhausted CD8+ T cells. PLoS Pathog 2015;11:e1005177.Abstract 679 Figure 1(a) Schematic depicting differentiation of CD8+ T cells to terminal exhaustion in cancer and subsequent suppression of local immune responses by expression of ectonucleosidase, CD39; (b) When assayed directly ex vivo, CD8+ terminally exhausted T (tTexh) cells, but not progenitor exhausted T (pTexh) cells, suppress effector functions as effectively as CD4+Foxp3+ Treg isolated from the same environment. Deletion of CD39 alleviates tTexh-mediated suppression; (c) CD8+ T cell suppression correlates with expression of CD39 on tTexh from various tumor models. (d) CD8+ T cell-specific deletion of CD39 slows tumor growth and improves immune response to checkpoint blockade-resistant tumors. Data are pooled from ≥3 experiments. Statistics are two-way ANOVA with multiple comparisons or Pearson correlation. ∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001, ∗∗∗∗p < 0.0001.

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