Necrosis Factor Receptor Family Member Research Articles

Abstract 349: The role of RELTfms and FLNA in human cancer and cellular apoptosis

Abstract Receptor Expressed in Lymphoid Tissues (RELT) is a Tumor Necrosis Factor Receptor family member implicated in several cancers. RELL1 and RELL2 (RELT-Like 1 and 2) are RELT homologs that bind RELT; the three proteins are collectively referred to as RELT family members (RELTfms). We sought to evaluate the role of the OXSR1 kinase and actin-binding protein Filamin A (FLNA) in modulating RELT-induced apoptosis of cancer cells. We also assessed RELTfm expression in human breast and lung cancer biopsies and their ability to sensitize breast cancer cells to chemotherapeutic agents. Methods: Empty vector or expression plasmids for RELTfms were transiently transfected into MDA-MB-231 (231) breast cancer cells with TransfeX reagent. Cell death was assessed by morphology assays and ATP luciferase assays. Apoptosis of 231 cells was assessed by Annexin V/PI staining using Flow cytometry (FC). Immunohistochemistry (IHC) was used to assess RELT expression in human breast and lung cancer biopsies. IHC and western blotting were utilized to determine RELT cellular localization. Results: All three RELLfms were co-immunoprecipitated by a C-terminal fragment of FLNA. RELT overexpression induced death in 231 cells, and this effect was increased with co-transfection of a FLNA S215A mutant, an important phosphorylation site that protects FLNA from cleavage. 231s transfected with RELT and RELL2 demonstrated increased Annexin V/PI signal in comparison to vector control, demonstrating that these RELTfms induce death via an apoptotic pathway. Co-transfection of a mutated plasmid for the OXSR1 kinase did not abrogate RELT-induced apoptosis. A RELT construct with a mutated binding site for the OXSR1 kinase induced apoptosis to a similar extent as wild-type RELT. An increase in doxorubicin-induced apoptosis was observed when 231 cells were transfected with RELL2 versus vector control. IHC results showed increased RELT expression in malignant breast cancer biopsies compared to patient-matched benign tissue. Interestingly, RELT was localized in the nucleus of some malignant lung cancer biopsies, and western blot analysis indicates that RELT translocates to the nucleus and interacts with chromatin in 231 cells. Conclusions: Collectively, these results demonstrate that RELTfms induce apoptosis of breast cancer cells, and potentially increase the sensitivity of breast cancer cells to chemotherapeutic agents. Furthermore, this work enhances our understanding of the interaction between RELT and FLN, a protein that is implicated in many cancers, including breast cancer. Phosphorylation by OXSR1 was previously shown to be required for RELT to activate the p38 pathway, yet the OXSR1 kinase is not required for RELT-induced death. RELT expression is enhanced in breast cancer biopsies, and interestingly, RELT can localize to the nucleus in cancerous cells. Collectively, these findings significantly enhance our understanding of RELTfms and cancer. Citation Format: Emily Chou, Esther Chang, Ihab Abed, Ashley Christensen, Kailey Nguyen, Anusri Yanumula, Yennie Shyu, Alyssa Abram, Jessa Alcaide, Gianne Cusick, Maryann Batiste, Yihui Shi, Eslam Mohammed, John Cusick. The role of RELTfms and FLNA in human cancer and cellular apoptosis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 349.

The short-chain fatty acid acetate coordinates with CD30 to modulate T-cell survival.

As an important substrate for cell metabolism, the short-chain fatty acid acetate emerges as a regulator of cell fate and function. However, its role in T-cell survival and its underlying mechanisms remain largely unknown. Here, we demonstrate that acetate modulates T-cell apoptosis via potentiation of α-tubulin acetylation. We further show that acetate treatment effectively increases the expression of the tumor necrosis factor receptor (TNFR) family member CD30 by enhancing its gene transcription. Moreover, CD30 physically associates with and stabilizes the deacetylase HDAC6, which deacetylates α-tubulin to decrease microtubule stability. Proteomic profiling of CD30 knockout (Cd30-/-) T-cells reveals elevated expression of anti-apoptotic BCL2 family proteins and thus promotes T-cell survival via a microtubule-Bcl-2 axis. Taken together, our results demonstrate that acetate is a regulator of T-cell survival by controlling levels of acetylated α-tubulin. This suggests that therapeutic manipulation of acetate metabolism may facilitate optimal T-cell responses in pathological conditions.

A Novel BCMA Immunohistochemistry Assay Reveals a Heterogenous and Dynamic BCMA Expression Profile in Multiple Myeloma

B-cell maturation antigen (BCMA) is a promising target for the treatment of multiple myeloma (MM) because the expression of this protein is largely limited to B-cell sets, plasma cells, MM, and other B-cell malignancies. Early studies assessing BCMA protein expression and localization have used insufficiently qualified immunohistochemistry assays, which have reported broad ranges of BCMA expression. As a result, our understanding of BCMA tissue expression derived from these data is limited, specifically the prevalence of BCMA expression on the cell surface/membrane, which has mechanistic relevance to the antimyeloma activity of several novel biotherapeutics. Here, we report on the qualification and application of a novel anti-BCMA immunohistochemistry antibody, 805G12. This antibody shows robust detection of BCMA in formalin-fixed, decalcified bone marrow tissue and provides key insights into membrane BCMA expression. The clone 805G12, which was raised against an intracellular C-terminal domain peptide of membrane BCMA, exhibited increased sensitivity and superior specificity across healthy and diseased tissue compared with the frequently referenced commercial reagent AF193. The new clone also demonstrated a broad range of expression of BCMA in MM and diffuse large B-cell lymphoma specimens. Additionally, cross-reactivity with closely related tumor necrosis factor receptor family members was observed with AF193 but not with 805G12. Furthermore, via established 805G12 and other independent BCMA assays, it was concluded that proteolytic processing by γ-secretase contributes to the levels of BCMA localized to the plasma membrane. As BCMA-directed therapeutics emerge to address the need for more effective treatment in the relapsed or refractory MM disease setting, the implementation of a qualified assay would ensure that reliable and consistent data on BCMA surface expression are used to inform clinical trial decisions and patient responses.

Abstract 3957: Receptor Activator of NF-κB (RANK) confers resistance to chemotherapy in AML and associates with dismal disease course

Abstract Acute myeloid leukemia (AML) is the most common form of acute leukemia in adults. Untreated, AML leads to death within months after first symptoms. Combinatorial chemotherapy, mostly using a pyrimidine analog together with an anthracycline, made this previously incurable disease medicable, and response to remission-inducing chemotherapy strongly correlates with patient outcome. Despite advances in treatment over the recent years, AML still has a poor prognosis with an average 5-year survival rate of 30%. A better understanding of the molecular mechanisms predicting and affecting treatment efficacy is key to improve disease control and outcome. Here we studied the expression, prognostic relevance and functional role of the tumor necrosis factor receptor (TNFR) family member Receptor Activator of Nuclear Factor (NF)-κB (RANK) in AML. We conducted an experimental ex vivo study using leukemic cells of 54 AML patients. Substantial surface expression of RANK was detected on the primary AML cells in 35% of the analyzed patients. We further found that RANK signaling induced the release of the cytokines IL-6, IL-8, TNF and IL-10 acting as growth and survival factors for the leukemic cells and mediated resistance of AML cells to treatment with doxorubicin and cytarabine, the most commonly used cytostatic compounds in AML treatment. In line, prevalence of RANK expression on leukemic cells correlated with dismal disease course of patients as revealed by reduced overall survival. Together, our results show that RANK plays a yet unrecognized role in AML pathophysiology and resistance to treatment. Moreover, the association of RANK expression with adverse disease course identifies RANK as potential “functional” prognostic marker and putative target for therapeutic intervention to improve treatment response of AML patients. Citation Format: Kim L. Clar, Lisa M. Weber, Bastian J. Schmied, Jonas S. Heitmann, Maddalena Marconato, Claudia Tandler, Pascal Schneider, Helmut R. Salih. Receptor Activator of NF-κB (RANK) confers resistance to chemotherapy in AML and associates with dismal disease course [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3957.

Abstract 1068: Anti-DR5 agonist IgM antibody IGM-8444 combined with SMAC mimetic birinapant induces strong synergistic tumor cytotoxicity

Abstract Apoptosis is induced through extrinsic and intrinsic signaling pathways. Extrinsic apoptosis can be activated through multimerization of death receptor 5 (DR5), a tumor necrosis factor (TNF) receptor family member highly expressed in many cancers. However, cellular resistance mechanisms within the intrinsic pathway may limit DR5 activity, including inhibitor of apoptosis proteins (IAPs) that block caspase activity or promote pro-survival NFκB signaling. Second mitochondria-derived activator of caspases (SMAC) is an endogenous bivalent IAP antagonist. Birinapant, a bivalent SMAC mimetic that binds and degrades IAPs, has been evaluated through Phase 2, demonstrating good safety and on target activity but minimal efficacy as a monotherapy. We hypothesized that simultaneously targeting the extrinsic apoptotic pathway with IGM-8444, an anti-DR5 multivalent IgM agonist, and the intrinsic apoptotic pathway with birinapant could enhance tumor cell apoptosis. Human cancer cell lines including triple negative breast cancer (TNBC), head and neck, ovarian, colorectal, lung, and sarcomas, were screened for sensitivity to IGM-8444 and birinapant combination. Strong synergistic cytotoxicity was observed in vitro in 36/45 (80%) cancer cell lines, as measured by both Bliss synergy score and maximal killing. IGM-8444 and birinapant combination also induced synergistic cytotoxicity in cells with acquired resistance to DR5 agonist antibodies. By contrast, IGM-8444 and birinapant did not kill primary human hepatocytes in vitro, demonstrating the potential clinical safety for this combination. In vivo, the IGM-8444 and birinapant combination dose-dependently reduced tumor growth in a MDA-MB-231 TNBC model, with 8/10 tumor-free mice at the highest dose of birinapant tested. By comparison, birinapant combination with an anti-DR5 IgG agonist showed a modest response. IGM-8444 and birinapant also showed significant anti-tumor responses in additional cell line and patient-derived xenograft models, including 7/9 tumor-free animals in a HT-1080 fibrosarcoma model and 9/10 complete responses in a EBC-1 lung squamous cell lung carcinoma model. Lastly, pharmacodynamic biomarkers including cIAP1 degradation, caspase activation, and caspase-cleaved cytokeratin 18 in tumor and serum correlated with anti-tumor response. In summary, combined targeting of the extrinsic and intrinsic apoptotic pathways with IGM-8444 and birinapant respectively enhances tumor cytotoxicity in multiple preclinical models. The combination of IGM-8444 with birinapant is currently under evaluation in a Phase 1 study in patients with relapsed and/or refractory solid cancers (NCT04553692). Citation Format: Beatrice T. Wang, Melanie Desbois, Susan E. Calhoun, Thomas J. Matthew, Poonam Yakkundi, Ling Wang, Xingjie Chen, Tasnim Kothambawala, Miho Oyasu, Maya F. Kotturi, Genevive Hernandez, Xiaohan Liu, Marvin S. Peterson, Eric W. Humke, Bruce A. Keyt, Angus M. Sinclair. Anti-DR5 agonist IgM antibody IGM-8444 combined with SMAC mimetic birinapant induces strong synergistic tumor cytotoxicity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1068.

Receptor Activator of NF-κB (RANK) Confers Resistance to Chemotherapy in AML and Associates with Dismal Disease Course.

Simple SummaryAcute myeloid leukemia (AML) is the most common form of acute leukemia in adults. Despite the emergence of new therapeutic agents in recent years, curation remains challenging, and new and better treatment options are needed. In the present study, we investigated the expression, prognostic significance, and functional role of the Receptor Activator of Nuclear Factor-κB (RANK) in AML. We found that RANK is expressed on leukemic cells in a substantial proportion of AML patients and is associated with a dismal disease course. We further demonstrated that signaling via RANK induces release of factors that favor AML cell survival and confers resistance to chemotherapeutics in AML treatment. Together, our findings identify RANK as novel prognostic marker and putative candidate for therapeutic intervention in AML to enhance response to treatment. Although treatment options of acute myeloid leukemia (AML) have improved over the recent years, prognosis remains poor. Better understanding of the molecular mechanisms influencing and predicting treatment efficacy may improve disease control and outcome. Here we studied the expression, prognostic relevance and functional role of the tumor necrosis factor receptor (TNFR) family member Receptor Activator of Nuclear Factor (NF)-κB (RANK) in AML. We conducted an experimental ex vivo study using leukemic cells of 54 AML patients. Substantial surface expression of RANK was detected on primary AML cells in 35% of the analyzed patients. We further found that RANK signaling induced the release of cytokines acting as growth and survival factors for the leukemic cells and mediated resistance of AML cells to treatment with doxorubicin and cytarabine, the most commonly used cytostatic compounds in AML treatment. In line, RANK expression correlated with a dismal disease course as revealed by reduced overall survival. Together, our results show that RANK plays a yet unrecognized role in AML pathophysiology and resistance to treatment, and identify RANK as “functional” prognostic marker in AML. Therapeutic modulation of RANK holds promise to improve treatment response in AML patients.

Protective Effect of TNFRSF11A rs7239667 G > C Gene Polymorphism on Coronary Outcome of Kawasaki Disease in Southern Chinese Population.

BackgroundThe main symptoms of Kawasaki disease (KD) are inflammatory vasculitis characterized by fever lasting 1–2 weeks, failure to respond to antibiotic treatment, conjunctivitis, redness of the lips and mouth, strawberry tongue, and painless enlargement of the neck lymph nodes. Studies have been shown that tumor necrosis factor (TNF) and TNF receptor family members are abnormally expressed in the acute phase of Kawasaki disease, also revealing that these two play a significant role in the pathogenesis of KD. The purpose of our study is to determine the relationship between TNFRSF11A rs7239667 and the pathogenesis of KD and Coronary artery lesions in KD.Methods and ResultsIn this study, TNFRSF11A (rs7239667) genotyping was performed in 1396 patients with KD and 1673 healthy controls. Our results showed that G > C polymorphism of TNFRSF11A (rs7239667) was not associated with KD susceptibility. In addition, the patients with KD were divided into CAA and NCAA groups according to whether they had coronary artery aneurysm (CAA) or not, and the TNFRSF11A rs7239667 genotyping was performed in the two groups. After gender and age calibration, We found that genotype CC of TNFRSF11A may be a protective factor in KD coronary artery damage (adjusted OR = 0.69 95% CI = 0.49–0.99 P = 0.0429) and is more significant in children with KD ≤ 60 months (adjusted OR = 0.49 95% CI = 0.49–0.93 P = 0.0173).ConclusionOur study suggests that TNFRSF11A rs7239667 G > C polymorphism maybe play a protective gene role for the severity of KD coronary artery injury and is related to age, which has not been previously revealed.

Role of necroptosis in infection-related, immune-mediated, and autoimmune skin diseases.

Regulated necrosis, also termed necroptosis, is another programmed cell death depending on a unique molecular pathway that does not overlap with apoptosis. Tumor necrosis factor and Toll-like receptor family members, interferon, and other mediators are the factors that mainly cause necroptosis. Activating necroptosis by ligands of death receptors requires the kinase activity of receptor-interacting proteins 1 and 3, and a mixed lineage kinase domain-like protein, which is a critical downstream mediator of necroptosis. Increasing evidence has revealed that necroptosis does not only involve physiological regulation but also the occurrence, development, and prognosis of certain diseases, such as septicemia, neurodegenerative diseases, and ischemic-reperfusion injury. Many excellent documented systematic discussions of necroptosis and its role in various skin diseases. In this review, we summarize the molecular mechanism of necroptosis, as well as the current knowledge on the contribution of necroptosis, in infection-related, immune-mediated, autoimmune skin diseases, and malignant skin tumors.

Abstract CT032: A phase 1/2, open-label, multicenter, dose escalation and efficacy study of mRNA-2416, a lipid nanoparticle encapsulated mRNA encoding human OX40L, for intratumoral injection alone or in combination with durvalumab for patients with advanced malignancies

Abstract Background: While PD-1/L1 blockade is an effective therapeutic approach for many patients with solid and hematologic malignancies, it is not sufficient to induce tumor regressions in the majority of patients. Optimal T cell responses require T cell receptor activation and co-stimulation, which can be provided via ligation of tumor necrosis factor receptor family members, such as OX40. Binding of OX40 by OX40L in the presence of a recognized antigen promotes CD4+ and CD8+ T cell expansion, enhances memory responses and inhibits regulatory T cell function. mRNA-2416 is a novel mRNA-based lipid nanoparticle therapeutic agent that expresses the wild type human OX40L. Preclinical in vivo anti-tumor activity of a murine mRNA-2416 surrogate and synergy with anti-PD-L1 antibodies in syngeneic cancer models are observed (unpublished). Here we present the findings of a first-in-human study of mRNA-2416 monotherapy delivered intratumorally in solid tumor patients with accessible lesions. Methods: This study tested the safety and efficacy of mRNA-2416 administered every 2 weeks for up to 12 doses in a standard 3+3 phase 1 dose escalation in patients with locally advanced, recurrent or metastatic solid malignancy or lymphoma. Tumor biopsies were collected pre- and post-treatment and evaluated by quantitative immunofluorescence (QIF) and RNA sequencing to characterize OX40L expression and immune response following treatment. Results: As of November 13, 2019, 39 patients have been treated at 4 dose levels from 1-8 mg. mRNA-2416 was generally well-tolerated with no DLTs. 6 out of 39 patients experienced grade 3 treatment related AEs. Out of 14 patients with best overall response of stable disease by RECIST, 6 had stable disease for ≥ 14 weeks, and 4 had tumor shrinkage in the injected lesions. Analyses of paired biopsies from injected lesions by QIF showed increased OX40L protein expression as well as elevated T cell scores post-treatment. Activation of a pro-inflammatory gene expression response post-treatment was observed in many cases, including increased cytolytic activity scores, elevated PD-L1 expression, and stimulation of a T cell-inflamed gene expression profile predictive of anti-PD-1/L1 response. These findings were observed in patients with long duration on study or tumor shrinkage. Conclusion: Intratumoral mRNA-2416 is tolerable at all dose levels studied when given as monotherapy and analyses of tumor post-treatment demonstrate increased OX40L protein expression, elevated PD-L1 levels and pro-inflammatory activity. Taken together with the observation of preclinical in vivo synergy with PD-L1 blockade, these data support the evaluation of a combination of intratumoral mRNA-2416 with the anti-PD-L1 inhibitor durvalumab in solid tumors, which is ongoing in part B of this study. Citation Format: Antonio Jimeno, Shilpa Gupta, Ryan Sullivan, Khanh T. Do, Wallace L. Akerley, Ding Wang, Deanna Teoh, Kurt Schalper, Sima J. Zacharek, Jing Sun, Andressa S. Laino, Joshua Frederick, Honghong Zhou, William Randolph, Stephanie Pascarella, Lisa Johansen, Pamela S. Cohen, ROBERT S. MEEHAN, Todd M. Bauer. A phase 1/2, open-label, multicenter, dose escalation and efficacy study of mRNA-2416, a lipid nanoparticle encapsulated mRNA encoding human OX40L, for intratumoral injection alone or in combination with durvalumab for patients with advanced malignancies [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT032.

Serum B-cell maturation antigen (BCMA) reduces binding of anti-BCMA antibody to multiple myeloma cells

B-cell maturation antigen (BCMA), a tumor necrosis factor receptor (TNFR) family member, is selectively expressed on terminally differentiated B-lymphocytes including multiple myeloma (MM) tumor cells. We sought to determine whether circulating (c)BCMA in MM serum interferes with antiBCMA antibody binding to MM cells. An enzyme-linked immunosorbent assay (ELISA) was used to determine serum (s) BCMA levels among 379 samples from patients with relapsed/refractory MM (RRMM). Furthermore, flow cytometric and immunofluorescent studies were used to examine if concentrations of BCMA in patients’ serum were high enough to interfere with the binding of anti-BCMA antibody to MM tumor cells. We have shown that BCMA is elevated in the serum from MM patients and that the median concentration of sBCMA from RRMM patients was 176 ng/mL (n = 379). Additionally, there was a consistent decrease in the binding of anti-BCMA antibody to MM tumor cells with sBCMA level ≥156 ng/mL. Together, these results demonstrate that circulating BCMA levels in most RRMM patients are high enough to interfere with anti-BCMA antibody binding to MM tumor cells and may interfere with BCMA-targeted immune-based therapies.

HVEM network signaling in cancer.

Somatic mutations in cancer cells may influence tumor growth, survival, or immune interactions in their microenvironment. The tumor necrosis factor receptor family member HVEM (TNFRSF14) is frequently mutated in cancers and has been attributed a tumor suppressive role in some cancer contexts. HVEM functions both as a ligand for the lymphocyte checkpoint proteins BTLA and CD160, and as a receptor that activates NF-κB signaling pathways in response to BTLA and CD160 and the TNF ligands LIGHT and LTα. BTLA functions to inhibit lymphocyte activation, but has also been ascribed a role in stimulating cell survival. CD160 functions to co-stimulate lymphocyte function, but has also been shown to activate inhibitory signaling in CD4+ T cells. Thus, the role of HVEM within diverse cancers and in regulating the immune responses to these tumors is likely context specific. Additionally, development of therapeutics that target proteins within this network of interacting proteins will require a deeper understanding of how these proteins function in a cancer-specific manner. However, the prominent role of the HVEM network in anti-cancer immune responses indicates a promising area for drug development.

Immunohistochemical Analysis of LGR5 and TROY Expression in Gastric Carcinogenesis Demonstrates an Inverse Trend

Background:Two of the Wnt signaling pathway target genes, tumor necrosis factor receptor family member (TROY) and leucine-rich G-protein coupled receptor (LGR5), are involved in the generation and maintenance of gastrointestinal epithelium. A negative modulatory role has recently been assigned to TROY, in this pathway. Here, we have examined their simultaneous expression in gastric carcinogenesis. Methods:Tumor and paired adjacent tissues of intestinal-type gastric cancer (GC) patients (n = 30) were evaluated for LGR5 and TROY expression by immunohistochemistry. The combination of the percentage of positively stained cells and the intensity of staining was defined as the composite score and compared between groups. The obtained findings were re-evaluated in a mouse model. Results:TROY expression in the tumor tissue was significantly lower than that of the adjacent tissue (2.5 ± 0.9 vs. 3.3 ± 0.9, p = 0.004), which was coincident with higher LGR5 expression (3.6 ± 1.1 vs. 2.7 ± 0.9, p = 0.001). This observation was prominent at stages II/III of GC, leading to a statistically significant mean difference of expression between these two molecules (p = 0.005). In the H. pylori infected-mouse model, this inverse expression was observed in transition from early (8-16 w) to late (26-50 w) time points, post treatment (p = 0.002). Conclusion:Our data demonstrates an inverse trend between TROY down-regulation and LGR5 up-regulation in GC tumors, as well as in response to H. pylori infection in mice. These findings support a potential negative modulatory role for TROY on LGR5 expression.

Abstract 4938: OX40 agonist antibody-based combination therapy with PI3Kβ selective inhibitor enhances T cell immunity

Abstract OX40 (CD134), a tumor necrosis factor (TNF) receptor family member, plays a critical role in initiating signaling cascades required for full activation of tumor-reactive T cells. Due to its distinct mechanism of action, the use of OX40 agonist-based combinations is emerging as a novel avenue to improve the effectiveness of cancer treatments. Our recently published studies demonstrate that oncogenic activation of the PI3K pathway by loss of the expression of tumor suppressor PTEN, imposes an immunosuppressive microenvironment in favor of tumor immune evasion. These results highlight the therapeutic potential of combinational therapy using OX40 agonists and PI3K inhibitors in cancer patients. In this study, we sought to evaluate the antitumor efficacy of the combination of an OX40 agonist antibody and a PI3Kβ selective inhibitor, GSK2636771, in tumors with PTEN loss. By using a genetically engineered mouse (GEM) model of melanoma, which can spontaneously develop tumors with PTEN loss, we observed that combination therapy using anti-OX40 and GSK2636771 significantly delayed tumor growth and improved survival time of mice bearing PTEN loss tumors. This combinational treatment was also well tolerated in experimental mice. Unlike the combination of GSK2636771 and immune checkpoint blockers, this combinational treatment did not result in an increase in the number of CD8+ tumor-infiltrating T cells, but significantly enhanced the percentage of Ki67+ CD8+ T cells at the tumor site when compared to either treatment alone. These results suggest that GSK2636771 treatment can synergize with OX40 agonists to augment effector functions of tumor-reactive T cells. To further confirm this synergistic effect, we measured serum levels of 45 cytokines/chemokines in tumor-bearing mice receiving anti-OX40 alone or in combination with GSK2636771. Serum levels of CCL4, CXCL10 and IFN-γ, which are mainly produced by memory and/or effector T cells, were significantly increased in mice in the combination cohort in comparison to the monotherapy cohorts. More importantly, using a vaccine mouse model, we demonstrate that GSK2636771 in combination with anti-OX40 did not significantly impair the generation and maintenance of memory T cells. Taken together, our results suggest that the combinational approach of an OX40 agonist antibody and GSK2636771 may induce robust and durable antitumor T cell immunity. Our study also provides a rationale to explore the clinical activity of an OX40 agonist antibody in combination with GSK2636771 in cancer patients with PTEN loss tumors. Citation Format: Weiyi Peng, Chunyu Xu, Brenda Melendez, Heather Jackson, Jodi A. McKenzi, Leila J. Williams, Yuan Chen, Rina M. Mbofung, Sara E. Leahey E. Leahey, Greg Lizee, Michael A. Davies, Niranjan Yanamandra, Patrick Hwu. OX40 agonist antibody-based combination therapy with PI3Kβ selective inhibitor enhances T cell immunity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4938.

The Ectodysplasin receptor EDAR acts as a tumor suppressor in melanoma by conditionally inducing cell death.

Ectodysplasin receptor EDAR is seen as a typical Tumor Necrosis Factor receptor (TNFR) family member known to interact with its ligand Eda-A1, and signaling mainly through the nuclear factor-kappaB (NF-κB) and c-jun N-terminal kinases pathways. Mutations in genes that encode proteins involved in EDAR transduction cascade cause anhidrotic ectodermal dysplasia. Here, we report an unexpected pro-apoptotic activity of EDAR when unbound to its ligand Eda-A1, which is independent of NF-κB pathway. Contrarily to other death receptors, EDAR does recruit caspase-8 to trigger apoptosis but solely upon ligand withdrawal, thereby behaving as the so-called dependence receptors. We propose that pro-apoptotic activity of unbound EDAR confers it a tumor suppressive activity. Along this line, we identified loss-of-pro-apoptotic function mutations in EDAR gene in human melanoma. Moreover, we show that the invalidation of EDAR in mice promotes melanoma progression in a B-Raf mutant background. Together, these data support the view that EDAR constrains melanoma progression by acting as a dependence receptor.

CD30 Is Dispensable for T-Cell Responses to Influenza Virus and Lymphocytic Choriomeningitis Virus Clone 13 but Contributes to Age-Associated T-Cell Expansion in Mice.

CD30 is a tumor necrosis factor receptor (TNFR) family member whose expression is associated with Hodgkin’s disease, anaplastic large cell lymphomas, and other T and B lymphoproliferative disorders in humans. A limited number of studies have assessed the physiological role of CD30/CD30 ligand interactions in control of infection in mice. Here, we assess the role of CD30 in T-cell immunity to acute influenza and chronic lymphocytic choriomeningitis virus (LCMV) clone 13 infection, two viral infections in which other members of the TNFR superfamily are important for T-cell responses. We show that CD30 is expressed on activated but not resting CD4 and CD8 T cells in vitro, as well as on regulatory T cells and marginally on T helper 1 cells in vivo during influenza infection. Despite this, CD4 and CD8 T-cell expansion in response to influenza virus was comparable in CD30+/+ and CD30−/− littermates, with no discernable role for the pathway in the outcome of influenza infection. Similarly, during persistent infection with LCMV clone 13, CD30 plays no obvious role in CD4 or CD8 T-cell responses, the level of T-cell exhaustion or viral control. In contrast, in the steady state, we observed increased numbers of total CD4 and CD8 T cells as well as increased numbers of regulatory T cells in unimmunized older (~8 months) CD30+/+ but not in CD30−/− age-matched littermates. Naive T-cell numbers were unchanged in the aged CD30+/+ mice compared to their CD30−/− littermate controls, rather the T-cell expansions were explained by an increase in CD4+ and CD8+ CD44mid-hiCD62L− effector memory cells, with a similar trend in the central memory T-cell compartment. In contrast, CD30 did not impact the numbers of T cells in young mice. These data suggest a role for CD30 in the homeostatic regulation of T cells during aging, contributing to memory T-cell expansions, which may have relevance for CD30 expression in human T-cell lymphoproliferative diseases.

RELT family members activate p38 and induce apoptosis by a mechanism distinct from TNFR1

Receptor Expressed in Lymphoid Tissues (RELT) is a human Tumor Necrosis Factor Receptor (TNFR) family member that has two identified homologous binding partners, RELL1 and RELL2. This study sought to further understand the pattern of RELT expression, the functional role of RELT family members, and the mechanism of RELT-induced apoptosis. RELT protein expression was detected in the spleen, lymph node, brain, breast and peripheral blood leukocytes (PBLs). A smaller than expected size of RELT was observed in PBLs, suggesting a proteolytically cleaved form of RELT. RELL1 and RELL2 overexpression activated the p38 MAPK pathway more substantially than RELT in HEK-293 cells, and this activation of p38 by RELT family members was blocked by dominant-negative mutant forms of OSR1 or TRAF2, implicating these molecules in RELT family member signaling. RELT was previously shown to induce apoptosis in human epithelial cells despite lacking the characteristic death domain (DD) found in other TNFRs. Seven deletion mutants of RELT that lacked differing portions of the intracellular domain were created to assess whether RELT possesses a novel DD. None of the deletion mutants induced apoptosis as efficiently as full-length RELT, a result that is consistent with a novel DD being located at the carboxyl-terminus. Interestingly, induction of apoptotic morphology by RELT overexpression was not prevented when signaling by FADD or Caspase-8 was blocked, indicating RELT induces apoptosis by a pathway distinct from other death-inducing TNFRs such as TNFR1. Collectively, this study provides more insights into RELT expression, RELT family member function, and the mechanism of RELT-induced death.

RIP1 has a role in CD40-mediated apoptosis in human follicular lymphoma cells

CD40 is a cell surface receptor which belongs to tumor necrosis factor receptor (TNFR) family members. It transmits signals that regulate diverse cellular responses such as proliferation, differentiation, adhesion molecule expression and apoptosis. Unlike other TNFR family members (TRAIL-R, Fas-R and TNFR1), the CD40 cytoplasmic tail lacks death domain. However, CD40 is capable of inducing apoptosis in different types of cancer cells including lymphoma. The apoptotic effect of CD40 is linked to the involvement of Fas, TRAIL or receptor interacting protein 1 (RIP1) kinase. We have previously shown that CD40 activation has anti-apoptotic or apoptotic effect in follicular lymphoma (FL) cell lines. In this study, we investigated the mechanism by which CD40 mediates apoptosis in a follicular lymphoma cell line, HF4.9. We show here that CD40-induced apoptosis was dependent on caspase-8 activation because caspase-8 specific inhibitor, Z-IETD-FMK completely prevented apoptosis. Therefore, the involvement of TRAIL, Fas and RIP1 in caspase-8 activation was examined. The exogenous TRAIL-induced apoptosis was fully prevented by anti-TRAIL neutralizing antibody. However, the antibody had no effect on CD40-induced apoptosis indicating that CD40 did not induce the expression of endogenous TRAIL in HF4.9 cells. Moreover, the cells were not sensitive to Fas-mediated apoptosis. Interestingly, RIP1 specific inhibitor, necrostatin-1 decreased CD40-induced apoptosis, which showed that RIP1 has a role in caspase-8 activation. In conclusion, the survival or apoptotic effects of CD40-mediated signaling might be related to the differentiation stages of FL cells.

The role of progranulin in arthritis.

Progranulin (PGRN) is a growth factor with a unique beads-on-a-string structure that is involved in multiple pathophysiological processes, including anti-inflammation, tissue repair, wound healing, neurodegenerative diseases, and tumorigenesis. This review presents up-to-date information concerning recent studies on the role of PGRN in inflammatory arthritis and osteoarthritis, with a special focus on the involvement of the interactions and interplay between PGRN and tumor necrosis factor receptor (TNFR) family members in regulating such musculoskeletal diseases. In addition, this paper highlights the applications of atsttrin, an engineered protein comprising three TNFR-binding fragments of PGRN, as a promising intervention in treating arthritis.

Immunohistochemical analysis of apoptosis and cell proliferation in lungs of premature infants with chronic lung disease (bronchopulmonary dysplasia)

Introduction: The pathophisiology of chronic lung disease (CLD), clinically known as bronchopulmonary dysplasia is not clear. It is believed that protective mechanisms, such as the release of inflammatory mediators and the activation of apoptotic and/or proliferative processes are activated in the lung tissue of premature infants in an attempt to repair tissue injury caused by exposure to oxygen and mechanical ventilation. Objective: Assess the presence of apoptosis and cell proliferation in the lungs of premature infants with CLD, exposed to oxygen and/or mechanical ventilation, by analyzing the proteins expression: proliferating cell nuclear antigen (PCNA), phosphatase and tensin homolog (PTEN), B-cell lymphoma 2 (Bcl-2), tumor necrosis factor receptor family member (Fas), fas-associated protein with death domain (FADD), tumor necrosis factor receptor type 1-associated death domain protein (TRADD), Caspase 3 and Caspase 8. Material and methods: We analyzed 32 infants autopsies at gestational age of less than 34 weeks exposed to oxygen therapy. The study was divided into three groups: classic CLD, new CLD and without CLD. Immunohistochemical analysis was performed. Results and discussion: A higher proliferation rate was observed in infants with CLD suggesting that longer exposure to mechanical ventilation may stimulates cell proliferation. The PTEN and Caspase 8 expressions were higher in the new CLD group, compared to the without CLD group, indicating that the new CLD form is more susceptible to apoptosis. Conclusion: Apoptosis and cell proliferation are involved in the pathophisiology of CLD. The new CLD form is more susceptible to apoptosis, while cell proliferation is more evident in the groups with CLD.

A potential osteoporosis target in the FAS ligand/FAS pathway of osteoblast to osteoclast signaling.

One of the pivotal factors in the health and maintenance of dense bone is the coordinated activity of osteoblasts and osteoclasts. Research scientists are developing an enormous knowledge base about the signaling that occurs between these two cell types with the goal of understanding the bone microenvironment under normal as well as resorptive disease states. This knowledge base has already led to the development of successful therapies for osteoporosis. The monoclonal antibody to receptor activator of nuclear factor-κB ligand (RANKL), known as Prolia ® (denosumab), is a recent example. RANKL is a cytokine expressed on the surface of the osteoblast in response to bone resorption cues like 1α,25-dihydroxyvitamin D3, parathyroid hormone (PTH), prostaglandin E 2 (PGE 2 ), and interleukin 11 (IL-11). A second cytokine, macrophage colony-stimulating factor (M-CSF), is released by the osteoblast on a continual basis with both cytokines promoting differentiation of osteoclast precursors. The osteoclast precursors express receptors for the two cytokines, c-Fms (M-CSF receptor) and RANK (RANKL receptor). Another ligand for c-Fms is IL-34, expressed primarily by splenic red pulp, which appears to act in concert with M-CSF and RANKL. Osteoblasts express a third factor which is a soluble tumor necrosis factor (TNF) receptor family member, osteoprotegrin (OPG), that serves as a “decoy” receptor for RANKL and thereby blocks RANKL-RANK binding to inhibit osteoclastogenesis. A construct of OPG in which the heparin-binding and death homology domains are removed and the remaining peptide is fused to the F c domain of the human immunoglobulin G1 (IgG1) is used for experimental therapeutic purposes. The resulting fusion protein construct is called OPG-F c , and it neutralizes RANKL. In a study of ovariectomized (OVX) rats, the combined use of OPG-F c and alendronate (a commonly used bisphosphonate) significantly increased the mechanical strength properties of femurs and lumbar vertebrae bodies compared to treatment with either OPG-F c or alendronate alone.