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Inhibition of immune checkpoints, including cytotoxic T-lymphocyte antigen-4 (CTLA-4), programmed death-1 (PD-1), and its ligand PD-L1, has demonstrated exciting and durable remissions across a spectrum of malignancies. Combinatorial regimens blocking complementary immune checkpoints further enhance the therapeutic benefit. The activity of these agents for patients with glioblastoma, a generally lethal primary brain tumor associated with significant systemic and microenvironmental immunosuppression, is not known. We therefore systematically evaluated the antitumor efficacy of murine antibodies targeting a broad panel of immune checkpoint molecules, including CTLA-4, PD-1, PD-L1, and PD-L2 when administered as single-agent therapy and in combinatorial regimens against an orthotopic, immunocompetent murine glioblastoma model. In these experiments, we observed long-term tumor-free survival following single-agent anti–PD-1, anti–PD-L1, or anti–CTLA-4 therapy in 50%, 20%, and 15% of treated animals, respectively. Combination therapy of anti–CTLA-4 plus anti–PD-1 cured 75% of the animals, even against advanced, later-stage tumors. In long-term survivors, tumor growth was not seen upon intracranial tumor rechallenge, suggesting that tumor-specific immune memory responses were generated. Inhibitory immune checkpoint blockade quantitatively increased activated CD8+ and natural killer cells and decreased suppressive immune cells in the tumor microenvironment and draining cervical lymph nodes. Our results support prioritizing the clinical evaluation of PD-1, PD-L1, and CTLA-4 single-agent targeted therapy as well as combination therapy of CTLA-4 plus PD-1 blockade for patients with glioblastoma. Cancer Immunol Res; 4(2); 124–35. ©2015 AACR.

Supplementary Methods

Supplemental Figure 1. Bioluminescence plots of individual animals following treatment with immune checkpoint blocking mAbs. Supplemental Figure 2. Immune cell infiltrates within intracranial GL261-luc2 tumor following treatment with isotype control IgG or combination therapy with CTLA-4 plus PD-1 mAb therapy. Supplemental Figure 3: Treatment antibody and detection antibody for PD-1 do not share same the epitope. Supplemental Figure 4. Representative immunohistochemistry results of intratumoral CD3+, CD4+ and CD8+ T cell infiltrates following immune checkpoint therapy with mAbs against CTLA-4, PD-1 and both CTLA-4 and PD-1. Supplemental Figure 5. Immune cell infiltration within the draining cervical lymph node (cLN) of GL261-luc2 tumor-bearing mice following treatment with isotype control IgG or combination therapy with mAbs against CTLA-4 plus PD-1. Supplemental Figure 6. Comparisons of chemokine expression levels in sera of mice treated with checkpoint blockade. Supplemental Figure 7: Expression of checkpoint ligands and receptors on GL261-Luc cells in vitro. Supplementary Table 1. Arrangement of chemokines on the Mouse Chemokine Antibody Array.

Supplementary Figure Legends

Di-2-pyridylketone-4,4,-dimethyl-3-thiosemicarbazone (Dp44mT) is being developed as an iron chelator with selective anticancer activity. We investigated the mechanism whereby Dp44mT kills breast cancer cells, both as a single agent and in combination with doxorubicin. Dp44mT alone induced selective cell killing in the breast cancer cell line MDA-MB-231 when compared with healthy mammary epithelial cells (MCF-12A). It induces G1 cell cycle arrest and reduces cancer cell clonogenic growth at nanomolar concentrations. Dp44mT, but not the iron chelator desferal, induces DNA double-strand breaks quantified as S139 phosphorylated histone foci (γ-H2AX) and Comet tails induced in MDA-MB-231 cells. Doxorubicin-induced cytotoxicity and DNA damage were both enhanced significantly in the presence of low concentrations of Dp44mT. The chelator caused selective poisoning of DNA topoisomerase IIα (top2α) as measured by an in vitro DNA cleavage assay and cellular topoisomerase-DNA complex formation. Heterozygous Nalm-6 top2α knockout cells (top2α+/−) were partially resistant to Dp44mT-induced cytotoxicity compared with isogenic top2α+/+ or top2β−/− cells. Specificity for top2α was confirmed using top2α and top2β small interfering RNA knockdown in HeLa cells. The results show that Dp44mT is cytotoxic to breast cancer cells, at least in part, due to selective inhibition of top2α. Thus, Dp44mT may serve as a mechanistically unique treatment for cancer due to its dual ability to chelate iron and inhibit top2α activity. [Cancer Res 2009;69(3):948–57]

Supplementary Figure 1 from The Iron Chelator Dp44mT Causes DNA Damage and Selective Inhibition of Topoisomerase IIα in Breast Cancer Cells

Supplementary Figure Legend and Methods from The Iron Chelator Dp44mT Causes DNA Damage and Selective Inhibition of Topoisomerase IIα in Breast Cancer Cells

PD-1 expression marks activated T cells susceptible to PD-1–mediated inhibition but not whether a PD-1–mediated signal is being delivered. Molecular predictors of response to PD-1 immune checkpoint blockade (ICB) are needed. We describe a monoclonal antibody (mAb) that detects PD-1 signaling through the detection of phosphorylation of the immunotyrosine switch motif (ITSM) in the intracellular tail of mouse and human PD-1 (phospho–PD-1). We showed PD-1+ tumor-infiltrating lymphocytes (TILs) in MC38 murine tumors had high phosphorylated PD-1, particularly in PD-1+TIM-3+ TILs. Upon PD-1 blockade, PD-1 phosphorylation was decreased in CD8+ TILs. Phospho–PD-1 increased in T cells from healthy human donors after PD-1 engagement and decreased in patients with Hodgkin lymphoma following ICB. These data demonstrate that phosphorylation of the ITSM motif of PD-1 marks dysfunctional T cells that may be rescued with PD-1 blockade. Detection of phospho–PD-1 in TILs is a potential biomarker for PD-1 immunotherapy responses.

Perceptions of hostile criticism (PHC) from close others are associated with poor individual functioning and low relationship satisfaction, whereas perceptions of constructive criticism (PCC) are associated with better relationship satisfaction. There is little empirical knowledge, however, regarding individual factors that contribute to such perceptions. The present study examined associations of overall emotion regulation difficulties, as well as the specific use of expressive suppression and cognitive reappraisal, with PHC and PCC. Both partners of 63 community couples completed global self-report measures. Sixty-one couples also completed similar measures immediately following each of three discussions during a laboratory session. Multilevel modeling analyses of global data indicated that individuals' reports of PHC were higher when they used more suppression and when both they and their partners reported greater difficulty in emotion regulation. Results with discussion-specific data were similar: Participants reported higher PHC in discussions when both they and their partners reported using more suppression or when they had more difficulties in emotion regulation during the discussions. Individuals reported higher levels of PCC when their partners reported using less suppression, both globally and in discussions. Finally, participants also reported higher levels of PCC in discussions when they reported using more reappraisal.

Blockade of immune cell co-inhibitory receptor PD-1 using monoclonal antibodies (mAbs) allows the development of anti-tumor immunity in various solid tumors and lymphoid malignancies. We recently demonstrated that PD-1 blockade elicits an anti-tumor immune response resulting in tumor rejection and long-term survival in approximately 50% of mice with intra-cranial GL-261 glioblastoma, despite the absence of accumulating CD8+ cytotoxic T cells in the tumor or draining lymph nodes. In this investigation, we provide evidence for the role of conventional CD4+ T cells and the innate immune response in PD-1 mediated anti-glioma immunity in this model. In response to anti-PD-1 monotherapy, intratumoral CD4+ T cells, but not CD8+ T cells, expressed significantly elevated levels of IFN-γ and TNF-α pro-inflammatory cytokines and the cytotoxic enzyme, granzyme B. Tbet, GATA3, and EOMES, transcription factors required for T cell proliferation, activation, and effector function, were also up-regulated in CD4+, but not CD8+ T cells in the brains of mice treated with PD-1 mAbs when compared to controls. We demonstrated that depletion of CD4+ or CD8+ T cells, but not NK, was sufficient to completely ablate anti-PD-1-mediated tumor eradication and long-term survival. CD4+ T cell activation was accompanied by the classical activation and M1 polarization of resident microglia and tumor-infiltrating macrophages. Together, these studies demonstrate for the first time a role for CD4+ T cells and the innate immune response in the eradication of glioblastoma by PD-1 blockade.

Oncolytic adenoviruses, such as Delta-24-RGD, are replication-competent viruses that are genetically engineered to induce selective cancer cell lysis. In cancer cells, Delta-24-RGD induces massive autophagy, which is required for efficient cell lysis and adenoviral spread. Understanding the cellular mechanisms underlying the regulation of autophagy in cells treated with oncolytic adenoviruses may provide new avenues to improve the therapeutic effect. In this work, we showed that cancer cells infected with Delta-24-RGD undergo autophagy despite the concurrent activation of the AKT/mTOR pathway. Moreover, adenovirus replication induced sustained activation of JNK proteins in vitro. ERK1/1 phosphorylation remained unchanged during adenoviral infection, suggesting specificity of JNK activation. Using genetic ablation and pharmacological inactivation of JNK, we unequivocally demonstrated that cells infected with Delta-24-RGD required JNK activation. Thus, genetic co-ablation of JNK1 and JNK2 genes or inhibition of JNK kinase function rendered Delta-24-RGD–treated cells resistant to autophagy. Accordingly, JNK activation induced phosphorylation of Bcl-2 and prevented the formation of Bcl-2/Beclin 1 autophagy suppressor complexes. Using an orthotopic model of human glioma xenograft, we showed that treatment with Delta-24-RGD induced phosphorylation and nuclear translocation of JNK, as well as phosphorylation of Bcl-2. Collectively, our data identified JNK proteins as an essential mechanistic link between Delta-24-RGD infection and autophagy in cancer cells. Activation of JNK without inactivation of the AKT/mTOR pathway constitutes a distinct molecular signature of autophagy regulation that differentiates Delta-24-RGD adenovirus from the mechanism used by other oncolytic viruses to induce autophagy and provides a new rationale for the combination of oncolytic viruses and chemotherapy.

Blockade of immune cell co-inhibitory receptor PD-1 using monoclonal antibodies (mAbs) allows the development of anti-tumor immunity in various solid tumors and lymphoid malignancies. We recently demonstrated that PD-1 blockade elicits an anti-tumor immune response resulting in tumor rejection and long-term survival in approximately 50% of mice with intra-cranial GL-261 glioblastoma, despite the absence of accumulating CD8+ cytotoxic T cells in the tumor or draining lymph nodes. In this investigation, we provide evidence for the role of conventional CD4+ T cells and the innate immune response in PD-1 mediated anti-glioma immunity in this model. In response to anti-PD-1 monotherapy, intratumoral CD4+ T cells, but not CD8+ T cells, expressed significantly elevated levels of IFN-γ and TNF-α pro-inflammatory cytokines and the cytotoxic enzyme, granzyme B. Tbet, GATA3, and EOMES, transcription factors required for T cell proliferation, activation, and effector function, were also up-regulated in CD4+, but not CD8+ T cells in the brains of mice treated with PD-1 mAbs when compared to controls. We demonstrated that depletion of CD4+ or CD8+ T cells, but not NK, was sufficient to completely ablate anti-PD-1-mediated tumor eradication and long-term survival. CD4+ T cell activation was accompanied by the classical activation and M1 polarization of resident microglia and tumor-infiltrating macrophages. Moreover, CSF-1 inhibition with PLX3397 to deplete microglia and macrophages did not affect tumor growth, but did lead to a significant survival advantage when combined with anti-PD-1 mAb. Together, these studies demonstrate for the first time a role for CD4+ T cells and the innate immune response in the eradication of glioblastoma by PD-1 blockade.

Background Combined immunotherapy approaches are promising cancer treatments. We evaluated anti-programmed cell death protein 1 (PD-1) treatment combined with gene-mediated cytotoxic immunotherapy (GMCI) performed by intratumoral injection of a prodrug metabolizing nonreplicating adenovirus (AdV-tk), providing in situ chemotherapy and immune stimulation. Methods The effects of GMCI on PD ligand 1 (PD-L1) expression in glioblastoma were investigated in vitro and in vivo. The efficacy of the combination was investigated in 2 syngeneic mouse glioblastoma models (GL261 and CT-2A). Immune infiltrates were analyzed by flow cytometry. Results GMCI upregulated PD-L1 expression in vitro and in vivo. Both GMCI and anti-PD-1 increased intratumoral T-cell infiltration. A higher percentage of long-term survivors was observed in mice treated with combined GMCI/anti-PD-1 relative to single treatments. Long-term survivors were protected from tumor rechallenge, demonstrating durable memory antitumor immunity. GMCI led to elevated interferon gamma positive T cells and a lower proportion of exhausted double positive PD1+TIM+CD8+ T cells. GMCI also increased PD-L1 levels on tumor cells and infiltrating macrophages/microglia. Our data suggest that anti-PD-1 treatment improves the effectiveness of GMCI by overcoming interferon-induced PD-L1-mediated inhibitory signals, and GMCI improves anti-PD-1 efficacy by increasing tumor-infiltrating T-cell activation. Conclusions Our data show that the GMCI/anti-PD-1 combination is well tolerated and effective in glioblastoma mouse models. These results support evaluation of this combination in glioblastoma patients.

Three studies examine whether the type of criticism (hostile vs. non-hostile) or the sex of the person perceiving criticism affect the association of criticism with relationship satisfaction. Analyses of the samples of undergraduates (Studies 1 and 2) and community couples (Study 3) indicated that hostile criticism was negatively associated with relationship functioning, whereas non-hostile criticism was positively associated with relationship functioning. The former association was stronger for women than for men (Studies 2 and 3), while the latter association was stronger for men than for women (Study 1). The results also suggest that hostile criticism may be more strongly associated with negative relationship processes in women than men, whereas non-hostile criticism may be more strongly associated with positive relationship processes for men than women.

Programmed death (PD)-1 pathway blockade is a successful strategy for cancer immunotherapy. However, only a limited number of patients respond. There is great need to identify predictors of therapeutic response to PD-1 immunotherapy. One challenge is that PD-1 expression can mark activated T cells, which are susceptible to PD-1-mediated inhibition, but does not indicate whether a PD-1-mediated immunoinhibitory signal is being delivered. Currently there are no methods to detect active PD-1 signaling and, in turn, successful PD-1 inhibition. Here, we describe a novel antibody that detects PD-1 signaling. This antibody detects phosphorylation of the immunotyrosine switch motif (ITSM) in the intracellular tail of both human and mouse PD-1 (phospho-PD-1). Using this anti-phospho-PD-1 mAb, we show that PD-1+ tumor infiltrating lymphocytes (TILs) in MC38 murine colorectal tumors have high levels of phosphorylated PD-1, particularly in PD-1+TIM-3+TILs. Upon PD-1 blockade, PD-1 phosphorylation is markedly decreased in TIM-3+CD8+ TILs prior to tumor clearance. We also observed decreased phospho PD-1 levels in T cells from peripheral blood of human lymphoma patients following treatment with PD-1 and LAG-3 mAb. These data demonstrate that phosphorylation of the ITSM of PD-1 marks dysfunctional T cells that may be rescued with PD-1 blockade. Analysis of phospho-PD-1 may serve as a potential biomarker for effective PD-1 immunotherapy.

Immune responses need to be controlled for optimal protective immunity and tolerance. Coinhibitory pathways in the B7-CD28 family provide critical inhibitory signals that regulate immune homeostasis and defense and protect tissue integrity. These coinhibitory signals limit the strength and duration of immune responses, thereby curbing immune-mediated tissue damage, regulating resolution of inflammation, and maintaining tolerance to prevent autoimmunity. Tumors and microbes that cause chronic infections can exploit these coinhibitory pathways to establish an immunosuppressive microenvironment, hindering their eradication. Advances in understanding T cell coinhibitory pathways have stimulated a new era of immunotherapy with effective drugs to treat cancer, autoimmune and infectious diseases, and transplant rejection. In this review we discuss the current knowledge of the mechanisms underlying the coinhibitory functions of pathways in the B7-CD28 family, the diverse functional consequences of these inhibitory signals on immune responses, and the overlapping and unique functions of these key immunoregulatory pathways.

Mitoquinone (MitoQ) is a synthetically modified, redox-active ubiquinone compound that accumulates predominantly in mitochondria. We found that MitoQ is 30-fold more cytotoxic to breast cancer cells than to healthy mammary cells. MitoQ treatment led to irreversible inhibition of clonogenic growth of breast cancer cells through a combination of autophagy and apoptotic cell death mechanisms. Relatively limited cytotoxicity was seen with the parent ubiquinone coenzyme Q(10.) Inhibition of cancer cell growth by MitoQ was associated with G(1)/S cell cycle arrest and phosphorylation of the checkpoint kinases Chk1 and Chk2. The possible role of oxidative stress in MitoQ activity was investigated by measuring the products of hydroethidine oxidation. Increases in ethidium and dihydroethidium levels, markers of one-electron oxidation of hydroethidine, were observed at cytotoxic concentrations of MitoQ. Keap1, an oxidative stress sensor protein that regulates the antioxidant transcription factor Nrf2, underwent oxidation, degradation, and dissociation from Nrf2 in MitoQ-treated cells. Nrf2 protein levels, nuclear localization, and transcriptional activity also increased following MitoQ treatment. Knockdown of Nrf2 caused a 2-fold increase in autophagy and an increase in G(1) cell cycle arrest in response to MitoQ but had no apparent effect on apoptosis. The Nrf2-regulated enzyme NQO1 is partly responsible for controlling the level of autophagy. Keap1 and Nrf2 act as redox sensors for oxidative perturbations that lead to autophagy. MitoQ and similar compounds should be further evaluated for novel anticancer activity.

Inhibition of immune checkpoints, including cytotoxic T-lymphocyte antigen-4 (CTLA-4), programmed death-1 (PD-1), and its ligand PD-L1, has demonstrated exciting and durable remissions across a spectrum of malignancies. Combinatorial regimens blocking complementary immune checkpoints further enhance the therapeutic benefit. The activity of these agents for patients with glioblastoma, a generally lethal primary brain tumor associated with significant systemic and microenvironmental immunosuppression, is not known. We therefore systematically evaluated the antitumor efficacy of murine antibodies targeting a broad panel of immune checkpoint molecules, including CTLA-4, PD-1, PD-L1, and PD-L2 when administered as single-agent therapy and in combinatorial regimens against an orthotopic, immunocompetent murine glioblastoma model. In these experiments, we observed long-term tumor-free survival following single-agent anti–PD-1, anti–PD-L1, or anti–CTLA-4 therapy in 50%, 20%, and 15% of treated animals, respectively. Combination therapy of anti–CTLA-4 plus anti–PD-1 cured 75% of the animals, even against advanced, later-stage tumors. In long-term survivors, tumor growth was not seen upon intracranial tumor rechallenge, suggesting that tumor-specific immune memory responses were generated. Inhibitory immune checkpoint blockade quantitatively increased activated CD8+ and natural killer cells and decreased suppressive immune cells in the tumor microenvironment and draining cervical lymph nodes. Our results support prioritizing the clinical evaluation of PD-1, PD-L1, and CTLA-4 single-agent targeted therapy as well as combination therapy of CTLA-4 plus PD-1 blockade for patients with glioblastoma. Cancer Immunol Res; 4(2); 124–35. ©2015 AACR.

Purpose: To determine if epacadostat, an oral indoleamine 2,3-dioxygenase (IDO1) inhibitor has therapeutic benefit against GBM when administered as single agent and with PD-1 blocking antibody. Methods: An initial survival experiment was performed to assess efficacy and was followed by an identical repeat experiment for validation. 1X105 luciferized GL261 cells, a murine GBM tumor line derived from intracerebral methylcholanthrene implantation, were stereotactically implanted intracranially in albino syngeneic C57BL/6 mice. Mice with increasing bioluminescence on days 3 and 6 were randomized (n=8/group) to receive treatment beginning on day 6: anti-PD-1 (332.8H3, mouse IgG1; 500 μg intraperitoneal (IP) on day 6, 250 μg q 3 days X 7); epacadostat (Incyte Corporation, orally dosed at 300 mg/kg/day for 5 days on/2days off for 3 weeks); anti-PD-1 + epacadostat; and control therapy (isotype IgG antibody IP and 0.5% methocel in water). Tumor response assessments were performed by quantifying bioluminescence and survival. A re-challenge experiment was performed in long-term survivors to assess for tumor immune responses capable of preventing relapse. All long-term surviving mice (defined as ≥ 100 days) from the efficacy experiment were injected with 1X105 GL261 cells in the contralateral hemisphere and followed for survival. Results: In both preclinical efficacy experiments, median survival in the epacadostat monotherapy group did not differ from controls (approximately 30 days). Four of 8 mice (50%) treated with anti-PD-1 were long-term survivors in both efficacy experiments. In the epacadostat plus anti-PD-1 combination group, 81% of the mice were long-term survivors (7 of 8 in experiment 1 and 6 of 8 in experiment 2). Of note, none of the long-term surviving mice developed evidence of tumor; thus the median survival among the anti-PD-1 and epacadostat plus anti-PD-1 combination groups were both > 100 days. In the re-challenge study, all of the mice who underwent GL261 re-inoculation survived > 100 more days with no evidence of tumor recurrence. Conclusions: IDO1 inhibition with epacadostat increased the eradication rate of anti-PD-1 therapy in an orthotopic syngeneic GBM model and long term survivors rejected tumor following orthotopic re-challenge. Further combinatorial studies incorporating IDO inhibitor therapy for GBM, including mechanistic studies, are warranted. Citation Format: David A. Reardon, Prafulla C. Gokhale, Sarah R. Klein, Kristen L. Jones, Paul T. Kirschmeier, Maria Speranza, Holly Koblish, Peggy Scherle, Lance Leopold, Robert Newton, Gordon J. Freeman. Inhibition of IDO1 with epacadostat enhances anti-tumor efficacy of PD-1 blockade in a syngeneic glioblastoma (GBM) model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 572. doi:10.1158/1538-7445.AM2017-572

Lessons from the history of cancer therapy inform that a multimodal approach offers the best potential to eradicate the tumor mass and prevent the recurrence after therapy. One of the most promising experimental therapies for cancer is the use of oncolytic adenoviruses as therapeutic agents. These biologic agents exert their function by directly infecting and killing tumor cells. The new progeny generated after the first infection round will spread, generating a therapeutic wave that will optimally eliminate every cancer cell. Recently, modifications in the virus genome have allowed for the designing of viruses that infect with more potency than wild-type adenoviruses, replicate exclusively in tumor cells, selectively target cellular receptors or molecular defects in the cancer cells, and deliver prodrug genes. In addition, these last-generation viruses can be combined with chemotherapy and other forms of cancer therapies to enhance the tumor killing capability. With the steady and fast pace of the progress in our knowledge of the genetics of tumors, we may soon fulfill our hope of reaching the final objective of an adenovirus-based personalized medicine for cancer.

Early clinical trial data show that blockade of PD-1 signaling leads to significant anticancer responses in a subset of patients in certain cancer types. While the brain has traditionally been considered to be an immune-privileged site, evidence supporting the use of immunotherapeutics in brain tumors has been rapidly accumulating. Given that virus-based cancer therapies can be immunostimulatory and immune checkpoint inhibitors block the body's natural checkpoint response, the combination of these two approaches offers a potentially advantageous interaction. One of the molecular underpinnings of T-cell exhaustion is the expression of Programmed Death-1 (PD-1) on T-cells that recognizes its ligand PD-L1. AdV-TK is an immunostimulatory virus-based approach, known as Gene-Mediated Cytotoxic Immunotherapy (GMCI), that involves the intra-tumoral delivery of a non-replicating adenoviral vector carrying the Herpes virus thymidine kinase gene (TK) followed by administration of an anti-herpetic prodrug (ganciclovir GCV) and recently showed encouraging results in a Phase II trial in glioblastoma (Wheeler et al., 2016). The immunological component results from the delivery vehicle being a virus, the mode of cell death, through both necrosis and apoptosis, and the pro-immunogenic properties of the TK protein. We confirm that this approach induces glioblastoma cell death and a consistent anti-tumor immune stimulation. Not surprisingly, however, this immune stimulation also leads to increase in cell surface of immune checkpoint inhibitory ligands on tumor cells, including PD-L1, detected by flow cytometry and immunohistochemistry. We show that GMCI induces a type-I interferon response, and using IFN decoy we demonstrated that the release of IFNβ in vitro is at least partially responsible for autocrine/paracrine PD-L1 up-regulation both in human and mouse glioblastoma cell lines. In vivo studies using an intracranial GL261 model showed high numbers of long term survivors in the GMCI/PD-1 combination (11/14), compared with GMCI (6/16), anti-PD-1 (5/12) and untreated (0/11). In addition, long term survival mice were no longer able to form tumors after rechallenge indicating the establishment of anti-tumor immunity. Finally, tumor infiltrating lymphocytes after GMCI showed an increase in CD8+, CD8+/GranzymeB+, and IFNγ+ cells suggestive of cytotoxic T-cell activation. However, there was also a significant increase in CD4+, CD4+/FoxP3+, and IL-10 indicating a significant infiltration by Tregs, releasing immunosuppressive cytokines. Additionally, there was a significant increase in PD-1+ /TIM3+ T-cells, indicative of an immunosuppressive microenvironment. Overall, our data show that GMCI/anti-PD-1 combinatorial therapy is effective in a syngeneic tumor model, and strongly support clinical trials of GMCI/checkpoint inhibitor combinations in glioblastoma patients. Citation Format: Maria Carmela Speranza, Franz Ricklefs, Carmela Passaro, Sarah R. Klein, Kazue Kasai, Johanna Kaufmann, Hiroshi Nakashima, Bronisz Agnieszka, Estuardo Aguilar-Cordova, Brian W. Guzik, Gordon J. Freeman, David A. Reardon, Patrick Wen, E. Antonio Chiocca, Sean E. Lawler. Preclinical analysis of combinatorial glioblastoma therapy with the prodrug-mediated gene therapy vector AdV-TK and immune checkpoint inhibition. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2016 Oct 20-23; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2017;5(3 Suppl):Abstract nr B84.

While the brain has traditionally been considered to be an immune-privileged site, evidence supporting the use of immunotherapeutics has been rapidly accumulating. Given that virus-based cancer therapies can be immunostimulatory and immune-checkpoint inhibitors block tumor-induced T-cell exhaustion, the combination of these two approaches offers a potentially synergistic interaction. One of the molecular underpinnings of T-cell exhaustion is the expression of Programmed Death-1 (PD1) on T-cells that recognizes its ligand PD-L1. AdV-tk is an immunostimulatory virus-based approach, known as Gene-Mediated Cytotoxic Immunotherapy (GMCI), that involves the intra-tumoral delivery of a non-replicating adenoviral vector carrying the Herpes virus thymidine kinase gene(TK) followed by administration of an anti-herpetic prodrug(ganciclovir-GCV) and recently showed encouraging results in a Phase II trial in glioblastoma(Wheeler et al.,2016). To provide a rationale for this therapeutic combination we investigated PD-L1 expression during GMCI therapy in human and mouse glioma cells in vitro and found that there was a consistent increase in cell surface PD-L1 levels. Interestingly, this was not associated with an increase of mRNA or protein. We also show that GMCI induces a type-I interferon response, and that the release of IFNβ is at least partially responsible for autocrine/paracrine PD-L1 up-regulation. In vivo studies using an intracranial GL261 model showed high levels of long term survivors in the GMCI/PD1 combination (11/14), compared with GMCI (6/16), anti-PD1 (5/12) and controls (0/11). In addition, tumor infiltrating lymphocytes after GMCI showed an increase in CD8+, CD8+/GranzymeB+, and CD8+/IFNγ+/TNFα+cells suggestive of cytotoxic T-cell activation. However, there was also a significant increase in CD4+, CD4+/FoxP3+, and IL-10 indicating a significant infiltration by Tregs, releasing immunosuppressive cytokines. Additionally, there was a significant increase in PD1+/TIM3+ T-cells, indicative of an immunosuppressive microenvironment. Overall, our data show that GMCI/anti-PD1 combinatorial therapy is effective in a syngeneic tumor model, and strongly support clinical trials of GMCI/checkpoint inhibitor combinations in glioblastoma patients. Citation Format: Maria Carmela Speranza, Kazue Kasai, Franz Ricklefs, Sarah R. Klein, Carmela Passaro, Hiroshi Nakashima, Johanna Kaufmann, Agnieszka Bronisz, Estuardo Aguilar-Cordova, Brian W. Guzik, Gordon J. Freeman, David A. Reardon, Patrick Wen, E. Antonio Chiocca, Sean E. Lawler. Preclinical analysis of combinatorial glioblastoma therapy with the prodrug-mediated gene therapy vector AdV-TK and immune checkpoint inhibition in GBM therapy [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr A075.

The mechanisms underlying adenovirus-mediated autophagy are currently unknown. Recently, members of the Bcl-2 protein family have been associated with autophagy. It was also reported that the Bcl-2 homology-3 (BH3) domain encompassed by both Beclin 1 and Bcl-2-like proteins is essential for their pro-autophagy or anti-autophagy functions. Here, we report for the first time that E1B19K, the adenovirus BH3 domain protein, interacts with Beclin 1 to initiate autophagy. Using immunoprecipitation assays we showed that expression of E1B19K in the host cell disrupted the physical interactions between Beclin 1 and Bcl-2 proteins. The displacement of Bcl-2 was coincident with the recruitment of PI3KC3 to the Beclin 1/E1B19K complexes. As a result of the changes in the components of the Beclin 1 interactome, there was activation of PI3KC3, as showed by the identification of PI3K-mediated lipid phosphorylation, and subsequent formation of autophagosomes. Importantly, the BH3 functional domain of E1B19K protein was required for the heterodimerization with Beclin 1. We also showed that transfer of E1B19K was sufficient to trigger autophagy in cancer cells. Consistent with these data, mutant adenoviruses encompassing a deletion of the E1B19K gene produced a marked deficiency in the capability of the virus to induce autophagy as showed by examining the lipidation and cleavage of LC3-I as well as the subcellular localization of LC3-II, the decrease in the levels of p62, and the formation of autophagosomes. Our work offers new information on the mechanisms of action of the adenoviral E1B19K protein as partner of Beclin 1 and positive regulator of autophagy.

The iron chelator Dp44mT is a potent topoisomerase IIα inhibitor with novel anticancer activity. Doxorubicin (Dox), the current front-line therapy for breast cancer, induces a dose-limiting cardiotoxicity, in part through an iron-mediated pathway. We tested the hypothesis that Dp44mT can improve clinical outcomes of treatment with Dox by alleviating cardiotoxicity.The general cardiac and renal toxicities induced by Dox were investigated in the presence and absence of Dp44mT. The iron chelating cardioprotectant Dexrazoxane (Drz), which is approved for this indication, was used as a positive control. In vitro studies were carried out with H9c2 rat cardiomyocytes and in vivo studies were performed using spontaneously hypertensive rats.Testing of the GI(50) profile of Dp44mT in the NCI-60 panel confirmed activity against breast cancer cells. An acute, toxic dose of Dox caused the predicted cellular and cardiac toxicities, such as cell death and DNA damage in vitro and elevated cardiac troponin T levels, tissue damage, and apoptosis in vivo. Dp44mT alone caused insignificant changes in hematological and biochemical indices in rats, indicating that Dp44mT is not significantly cardiotoxic as a single agent. In contrast to Drz, Dp44mT failed to mitigate Dox-induced cardiotoxicity in vivo.We conclude that although Dp44mT is a potent iron chelator, it is unlikely to be an appropriate cardioprotectant against Dox-induced toxicity. However, it should continue to be evaluated as a potential anticancer agent as it has a novel mechanism for inhibiting the growth of a broad range of malignant cell types while exhibiting very low intrinsic toxicity to healthy tissues.

Di-2-pyridylketone-4,4,-dimethyl-3-thiosemicarbazone (Dp44mT) is being developed as an iron chelator with selective anticancer activity. We investigated the mechanism whereby Dp44mT kills breast cancer cells, both as a single agent and in combination with doxorubicin. Dp44mT alone induced selective cell killing in the breast cancer cell line MDA-MB-231 when compared with healthy mammary epithelial cells (MCF-12A). It induces G1 cell cycle arrest and reduces cancer cell clonogenic growth at nanomolar concentrations. Dp44mT, but not the iron chelator desferal, induces DNA double-strand breaks quantified as S139 phosphorylated histone foci (γ-H2AX) and Comet tails induced in MDA-MB-231 cells. Doxorubicin-induced cytotoxicity and DNA damage were both enhanced significantly in the presence of low concentrations of Dp44mT. The chelator caused selective poisoning of DNA topoisomerase IIα (top2α) as measured by an in vitro DNA cleavage assay and cellular topoisomerase-DNA complex formation. Heterozygous Nalm-6 top2α knockout cells (top2α+/−) were partially resistant to Dp44mT-induced cytotoxicity compared with isogenic top2α+/+ or top2β−/− cells. Specificity for top2α was confirmed using top2α and top2β small interfering RNA knockdown in HeLa cells. The results show that Dp44mT is cytotoxic to breast cancer cells, at least in part, due to selective inhibition of top2α. Thus, Dp44mT may serve as a mechanistically unique treatment for cancer due to its dual ability to chelate iron and inhibit top2α activity. [Cancer Res 2009;69(3):948–57]

We sought to determine whether premenstrual mood symptoms exhibit familial aggregation in bipolar disorder or major depression pedigrees. Two thousand eight hundred seventy-six women were interviewed with the Diagnostic Interview for Genetic Studies as part of either the NIMH Genetics Initiative Bipolar Disorder Collaborative study or the Genetics of Early Onset Major Depression (GenRED) study and asked whether they had experienced severe mood symptoms premenstrually. In families with two or more female siblings with bipolar disorder (BP) or major depressive disorder (MDD), we examined the odds of having premenstrual mood symptoms given one or more siblings with these symptoms. For the GenRED MDD sample we also assessed the impact of personality as measured by the NEO-FFI. Premenstrual mood symptoms did not exhibit familial aggregation in families with BP or MDD. We unexpectedly found an association between high NEO openness scores and premenstrual mood symptoms, but neither this factor, nor NEO neuroticism influenced evidence for familial aggregation of symptoms. Limitations include the retrospective interview, the lack of data on premenstrual dysphoric disorder, and the inability to control for factors such as medication use.

Adenoviruses are innately immunogenic; thus, targeted immunotherapy with recombinant, oncolytic adenoviruses is under investigation for the treatment of cancer. Evidence indicates adenoviruses induce autophagy that is required for cancer cell lysis. Importantly, autophagy is known to promote the presentation of self and foreign antigens for immune cell activation. The molecular regulation of autophagy and antigen presentation in adenovirus- infected cells remains undefined. Our data indicates adenovirus infection triggered phosphorylation of c-Jun N-terminal kinases (JNK) in vitro and in vivo, which was essential for autophagy. JNK-dependent B cell lymphoma-2 (Bcl-2) phosphorylation stimulated the dissociation of Bcl-2/beclin 1 heterodimers, enabling beclin 1 to initiate autophagy. Additionally, our data demonstrated for the first time that adenoviral epitopes were presented at the surface of infected cells through JNK- and autophagy-dependent mechanisms, as infected JNK- and autophagy-deficient cells were unable to activate splenocytes from adenovirus-immunized mice. Rapamycin, a chemical activator of autophagy, was able to enhance adenoviral antigen presentation. Contrary to starvation-induced autophagy, inhibiting adenovirus-mediated autophagy and antigen presentation required genetic knock-out of both JNK1 and JNK2 isoforms. We propose this unique mechanism for the processing of adenoviral antigens and consequent activation of immune cells can be leveraged in developing recombinant adenoviruses for the advancement of anti-tumor immunotherapy. Thus, we developed a novel adenovirus that expresses a chimeric fiber protein containing the cancer-specific, immunogenic epitope from the epidermal growth factor receptor variant III (EGFRvIII). We confirmed that the EGFRvIII epitope was presented at the surface of cells in an autophagy-dependent manner that could be enhanced by the pro-inflammatory cytokine, interferon gamma. Thus, we discovered molecular events regulating adenovirus-mediated autophagy and antigen presentation that differs from the conventional paradigm which could be employed for the advancement of adenovirus-based vaccines. Citation Format: Sarah Renee Klein. C-Jun N-terminal kinases and autophagy promote adenoviral and ectopic tumor-associated antigen presentation. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3644. doi:10.1158/1538-7445.AM2014-3644

Oncolytic adenoviruses are being examined as potential therapeutic agents for malignant gliomas and other solid tumors. We have reported that autophagy is a key component of the lysis process in adenovirus-infected cells, influencing the adenoviral spread. We hypothesize that understanding the regulation of autophagy should result in the generation of more potent oncolytic adenoviruses. Our group showed that the function of adenoviral early E1B-proteins include regulation of autophagy. Thus, E1B19k, a Bcl2-like protein, interacts with Beclin 1 and activates autophagy in adenovirus-infected cells. (Piya et al., PLOS One 2011). In this work, we sought to examine the capability of the E1B55K to modulate the autophagic process. Using mutant viruses deficient for the expression of E1B55k, E4orf6 or E1B55k/E4orf6, we observed that viruses lacking the expression of E1B55k were attenuated for the induction of autophagy. Upon examining the sequence of E1B55k, we discovered the presence of an LC3-interacting motif, termed LIR. Co-immunoprecipation assays revealed that E1B55k heterodimerized with LC3. As expected, mutations in the LIR sequence of E1B55k abrogated the physical interaction with LC3. Importantly, we showed that disruption of E1B55k/LC3 complexes had functional repercussions resulting in attenuation of the adenovirus-mediated autophagy. Because the complex of E1B55k and E4orf6 functions as a sumo ligase, we examined whether E1B55k/E4orf6 complexes were involved in LC3 sumoylation. Using co-immunoprecipitation studies in HeLa-6X-his-Sumo-1 infected with wild type and mutant adenoviruses, we showed that LC3 was sumoylated during adenoviral infection and that E1B55k/LC3 interactions were required for this posttranslational modification. Importantly, inhibition of the sumoylation process drastically reduced adenovirus replication. This is the first report showing that adenovirus induced sumoylation of cellular proteins to regulate autophagy. Preliminary studies of cytoplasmic and nuclear contents of LC3 and sumoylated LC3 suggest that adenovirus-mediated sumoylation of LC3 prolongs the presence of LC3 in the cytoplasm by modifying subcellular localization and decreasing protein degradation. We conclude that adenoviral E1B proteins cooperate in the induction and maintenance of autophagy in host cells. Our data provide new insights about the regulation of autophagy and the intracellular environment generated in cells infected with adenoviruses. It is hoped that these findings will propel the development of more potent and selective oncolytic adenoviruses. Citation Format: Sujan Piya, Hong Jiang, Sarah Klein, W.K.Alfred Yung, Raymond Sawaya, Candelaria Gomez-Manzano, Juan Fueyo. Oncolytic adenoviruses modulate autophagy in cancer cells via sumoylation of LC3. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 726. doi:10.1158/1538-7445.AM2014-726

Glioblastoma multiforme is the most common and lethal form of primary brain tumor in adults. Targeted immunotherapy using recombinant oncolytic viruses is a promising strategy for the treatment of brain tumors. Delta-24-RGD is a highly selective and potent oncolytic adenovirus that induces autophagy in malignant gliomas. Data from our ongoing clinical trial suggested Delta-24-RGD initiated an anti-tumor immune response in patients. Importantly, autophagy promotes the presentation of viral antigens for activation of immune cells; therefore, we sought to elucidate the molecular mechanisms by which adenoviruses induce autophagy. Adenoviral replication induced phosphorylation of JNK that was required for autophagy. Our results indicated that JNK regulates autophagy through Bcl-2 phosphorylation and consequent dissociation of Bcl-2 and beclin 1. Contrary to starvation-induced autophagy, adenovirus-mediated autophagy was facilitated by both JNK1 and JNK2 isoforms of JNK. Moreover, our data indicated that adenoviral antigens were presented at the cell surface, which was ablated upon down-regulation of JNK or autophagy. We propose a JNK/autophagy-dependent mechanism for the immune presentation of viral antigens that can be leveraged when developing recombinant adenoviruses for the advancement of anti-tumor immunotherapy. Thus, we developed a genetically-modified Delta-24 adenovirus expressing an EGFRvIII epitope that is aberrantly expressed in gliomas. The majority (>80%) of cells infected with Delta-24-FvIII presented the fiber-bound EGFRvIII epitope on their surface, an effect that was diminished upon inhibition of autophagy. Our data demonstrated that oncolytic adenoviruses can be modified to present cancer antigens for an anti-tumor immune response that may be enhanced by positively regulating autophagy. Citation Format: Sarah R. Klein, Hong Jiang, Sujan Piya, Zhimin Lu, Candelaria Gomez-Manzano, Juan Fueyo. The role of JNK isoforms in adenovirus-induced autophagy: Implications for cancer immunotherapy using oncolytic adenoviruses. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology: Multidisciplinary Science Driving Basic and Clinical Advances; Dec 2-5, 2012; Miami, FL. Philadelphia (PA): AACR; Cancer Res 2013;73(1 Suppl):Abstract nr B97.

Purpose: Delta-24-RGD is a highly selective and potent oncolytic adenovirus that is currently being tested in a clinical trial for patients with malignant gliomas. The mechanism of oncolysis for Delta-24-RGD is defined as autophagic cell death, yet the signal transduction and molecular interactions responsible remain uncharacterized. Methods: Utilizing JNK1- and JNK2-null mouse embryonic fibroblasts, we analyzed the involvement of JNK in Bcl-2 phosphorylation and degradation, and adenoviral-induced autophagy. Mutations at the phosphorylation sites of Bcl-2 were employed to determine which are necessary for release of Beclin 1, degradation of Bcl-2, and induction of autophagy by adenovirus. Results: In this report, we reveal that activation of c-Jun N-terminal kinase 1 (JNK1) is required to initiate and maintain autophagy induced by wild-type and Delta-24-RGD adenoviruses in the host cell. In addition, JNK1-dependent phosphorylation of Bcl-2 at serine 87 (but not serine 70) and subsequent inhibition of Bcl-2:Beclin 1 heterodimerization is necessary for autophagy to occur in infected cells. Upon phosphorylation and release from Beclin 1, Bcl-2 is degraded by the proteosome. Finally, the activation of JNK leads to its translocation to the nucleus and results in the transcription of autophagy-related (ATG) genes for the maintenance of autophagy, as yet undocumented in mammalian cells. Conclusion: Adenoviruses have thus evolved a highly complex mechanism of regulating autophagy which differs from the typical cellular stress response that may be exploited in the treatment of gliomas. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2871. doi:10.1158/1538-7445.AM2011-2871