Early immune factors associated with the development of post-acute sequelae of SARS-CoV-2 infection in hospitalized and non-hospitalized individuals.

Background: Infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can lead to post-acute sequelae of SARS-CoV-2 (PASC) that can persist for weeks to years following initial viral infection. Clinical manifestations of PASC are heterogeneous and often involve multiple organs. While many hypotheses have been made on the mechanisms of PASC and its associated symptoms, the acute biological drivers of PASC are still unknown. Methods: We enrolled 494 patients with COVID-19 at their initial presentation to a hospital or clinic and followed them longitudinally to determine their development of PASC. From 341 patients, we conducted multi-omic profiling on peripheral blood samples collected shortly after study enrollment to investigate early immune signatures associated with the development of PASC. Results: During the first week of COVID-19, we observed a large number of differences in the immune profile of individuals who were hospitalized for COVID-19 compared to those individuals with COVID-19 who were not hospitalized. Differences between individuals who did or did not later develop PASC were, in comparison, more limited, but included significant differences in autoantibodies and in epigenetic and transcriptional signatures in double-negative 1 B cells, in particular. Conclusions: We found that early immune indicators of incident PASC were nuanced, with significant molecular signals manifesting predominantly in double-negative B cells, compared with the robust differences associated with hospitalization during acute COVID-19. The emerging acute differences in B cell phenotypes, especially in double-negative 1 B cells, in PASC patients highlight a potentially important role of these cells in the development of PASC.

The safety and efficacy of systemic delivery of a new liver-de-targeted TGFß signaling inhibiting adenovirus in an immunocompetent triple negative mouse mammary tumor model.

Aberrant TGFß signaling is linked to metastasis and tumor immune escape of many cancers including metastatic triple negative breast cancer (mTNBC). Previously, we have found that oncolytic adenoviruses expressing a TGFß signaling inhibitory protein (sTGFßRIIFc) induced immune activation in a mouse TNBC (4T1) immunocompetent subcutaneous model with intratumoral injection. Systemic administration of adenoviruses can be a superior route to treat mTNBC but faces the challenges of increased toxicity and viral clearance. Thus, we created a liver-de-targeted sTGFßRIIFc- and LyP-1 peptide-expressing adenovirus (mHAdLyp.sT) with enhanced breast cancer cell tropism. Its safety and immune response features were profiled in the 4T1 model. Our data showed that the systemic administration of mHAdLyp.sT resulted in reduced hepatic and systemic toxicity. mHAdLyp.sT was also effective in increasing Th1 cytokines and anti-tumor cell populations by cytokine analysis, spleen/tumor qRT-PCR, and flow cytometry. We further tested the therapeutic effects of mHAdLyp.sT alone and in combination with immune checkpoint inhibitors (ICIs). mHAdLyp.sT alone and with all ICI combinations elicited significant inhibition of lung metastasis by histological analysis. When mHAdLyp.sT was combined with both anti-PD-1 and anti-CTLA-4 antibodies, primary 4T1 tumor growth was also significantly inhibited. We are confident in advancing this new treatment option for mTNBC.

Distinct temporal trajectories and risk factors for Post-acute sequelae of SARS-CoV-2 infection.

Background: The understanding of Post-acute sequelae of SARS-CoV-2 infection (PASC) can be improved by longitudinal assessment of symptoms encompassing the acute illness period. To gain insight into the various disease trajectories of PASC, we assessed symptom evolution and clinical factors associated with the development of PASC over 3 months, starting with the acute illness period. Methods: We conducted a prospective cohort study to identify parameters associated with PASC. We performed cluster and case control analyses of clinical data, including symptomatology collected over 3 months following infection. Results: We identified three phenotypic clusters associated with PASC that could be characterized as remittent, persistent, or incident based on the 3-month change in symptom number compared to study entry: remittent (median; min, max: -4; -17, 3), persistent (-2; -14, 7), or incident (4.5; -5, 17) (p = 0.041 remittent vs. persistent, p < 0.001 remittent vs. incident, p < 0.001 persistent vs. incident). Despite younger age and lower hospitalization rates, the incident phenotype had a greater number of symptoms (15; 8, 24) and a higher proportion of participants with PASC (63.2%) than the persistent (6; 2, 9 and 52.2%) or remittent clusters (1; 0, 6 and 18.7%). Systemic corticosteroid administration during acute infection was also associated with PASC at 3 months [OR (95% CI): 2.23 (1.14, 4.36)]. Conclusion: An incident disease phenotype characterized by symptoms that were absent during acute illness and the observed association with high dose steroids during acute illness have potential critical implications for preventing PASC.

Identification of potential COVID-19 treatment compounds which inhibit SARS Cov2 prototypic, Delta and Omicron variant infection.

Recurrent waves of COVID19 remain a major global health concern. Repurposing either FDA-approved or clinically advanced drug candidates can save time and effort required for validating the safety profile and FDA approval. However, the selection of appropriate screening approaches is key to identifying novel candidate drugs with a higher probability of clinical success. Here, we report a rapid, stratified two-step screening approach using pseudovirus entry inhibition assay followed by an infectious prototypic SARS CoV2 cytotoxic effect inhibition assay in multiple cell lines. Using this approach, we screened a library of FDA-approved and clinical-stage drugs and identified four compounds, apilimod, berbamine, cepharanthine and (S)-crizotinib which potently inhibited SARS CoV2-induced cell death. Importantly, these drugs exerted similar inhibitory effect on the delta and omicron variants although they replicated less efficiently than the prototypic strain. Apilimod is currently under clinical trial (NCT04446377) for COVID19 supporting the validity and robustness of our screening approach.

Inhibition of IRAK4 dysregulates SARS-CoV-2 spike protein-induced macrophage inflammatory and glycolytic reprogramming.

Escalated innate immunity plays a critical role in SARS-CoV-2 pathology; however, the molecular mechanism is incompletely understood. Thus, we aim to characterize the molecular mechanism by which SARS-CoV-2 Spike protein advances human macrophage (MÏ´) inflammatory and glycolytic phenotypes and uncover novel therapeutic strategies. We found that human MÏ´s exposed to Spike protein activate IRAK4 phosphorylation. Blockade of IRAK4 in Spike protein-stimulated MÏ´s nullifies signaling of IRAK4, AKT, and baseline p38 without affecting ERK and NF-κB activation. Intriguingly, IRAK4 inhibitor (IRAK4i) rescues the SARS-CoV-2-induced cytotoxic effect in ACE2+HEK 293 cells. Moreover, the inflammatory reprogramming of MÏ´s by Spike protein was blunted by IRAK4i through IRF5 and IRF7, along with the reduction of monokines, IL-6, IL-8, TNFα, and CCL2. Notably, in Spike protein-stimulated MÏ´s, suppression of the inflammatory markers by IRAK4i was coupled with the rebalancing of oxidative phosphorylation over metabolic activity. This metabolic adaptation promoted by IRAK4i in Spike protein-activated MÏ´s was shown to be in part through constraining PFKBF3, HIF1α, cMYC, LDHA, lactate expression, and reversal of citrate and succinate buildup. IRAK4 knockdown could comparably impair Spike protein-enhanced inflammatory and metabolic imprints in human MÏ´s as those treated with ACE2, TLR2, and TLR7 siRNA. Extending these results, in murine models, where human SARS-CoV-2 Spike protein was not recognized by mouse ACE2, TLRs were responsible for the inflammatory and glycolytic responses instigated by Spike protein and were dysregulated by IRAK4i therapy. In conclusion, IRAK4i may be a promising strategy for severe COVID-19 patients by counter-regulating ACE2 and TLR-mediated MÏ´ hyperactivation. IRAK4i therapy counteracts MÏ´ inflammatory and glycolytic reprogramming triggered by Spike protein. This study illustrates that SARS-CoV-2 Spike protein activates IRAK4 signaling via ACE2 as well as TLR2 and TLR7 sensing in human MÏ´s. Remarkably, IRAK4i treatment can dysregulate both ACE-dependent and independent (via TLR sensing) SARS-CoV-2 Spike protein-activated inflammatory and metabolic imprints.

Restoration of Follicular T Regulatory/Helper Cell Balance by OX40L-JAG1 Cotreatment Suppresses Lupus Nephritis in NZBWF1/j Mice.

Class-switched antinuclear autoantibodies produced by T follicular helper (TFH) cell-dependent germinal center (GC) B cell response play an essential pathogenic role in lupus nephritis (LN). The role of T follicular regulatory (TFR) cells, an effector subset of CD4+Foxp3+ T regulatory cells (Tregs), which are specialized in suppressing TFH-GC response and Ab production, remains elusive in LN. Contrasting reports have shown increased/reduced circulating TFR cells in human lupus that might not accurately reflect their presence in the GCs of relevant lymphoid organs. In this study, we report a progressive reduction in TFR cells and decreased TFR/TFH ratio despite increased Tregs in the renal lymph nodes of NZBWF1/j mice, which correlated with increased GC-B cells and proteinuria onset. Cotreatment with soluble OX40L and Jagged-1 (JAG1) proteins increased Tregs, TFR cells, and TFR/TFH ratio, with a concomitant reduction in TFH cells, GC B cells, and anti-dsDNA IgG Ab levels, and suppressed LN onset. Mechanistic studies showed attenuated TFH functions and diminished GC events such as somatic hypermutation and isotype class-switching in OX40L-JAG1-treated mice. RNA sequencing studies revealed inhibition of hypoxia-inducible factor 1-α (HIF-1a) and STAT3 signaling in T conventional cells from OX40L-JAG1-treated mice, which are critical for the glycolytic flux and differentiation into TFH cell lineage. Therefore, the increased TFR/TFH ratio seen in OX40L-JAG1-treated mice could involve both impaired differentiation of TFH cells from T conventional cells and expansion of TFR cells. We show a key role for GC-TFR/TFH imbalance in LN pathogenesis and how restoring homeostatic balance can suppress LN.

LIGHT enhanced bispecific antibody armed T-cells to treat immunotherapy resistant colon cancer.

Increased tumor infiltrating lymphocytes (TIL) are associated with improved patient responses to immunotherapy. As a result, there is interest in enhancing lymphocyte trafficking particularly to colon cancers since the majority are checkpoint blockade-resistant and microsatellite stable. Here, we demonstrate that activated T-cells (ATC) armed with anti-CD3 x anti-EGFR bispecific antibody increases TIL and mediate anti-tumor cytotoxicity while decreasing tumor cell viability. Furthermore, treatment induces endogenous anti-tumor immunity that resisted tumor rechallenge and increased memory T-cell subsets in the tumor. When combined with targeted tumor expression of the tumor necrosis factor superfamily member LIGHT, activated T-cell proliferation and infiltration were further enhanced, and human colorectal tumor regressions were observed. Our data indicate that tumor-targeted armed bispecific antibody increases TIL trafficking and is a potentially potent strategy that can be paired with combination immunotherapy to battle microsatellite stable colon cancer. SIGNIFICANCE: Enhancing trafficking of tumor infiltrating lymphocytes (TILs) to solid tumors has been shown to improve outcomes. Unfortunately, few strategies have been successful in the clinical setting for solid tumors, particularly for "cold" microsatellite stable colon cancers. In order to address this gap in knowledge, this study combined TNFSF14/LIGHT immunomodulation with a bispecific antibody armed with activated T-cells targeted to the tumor. This unique T-cell trafficking strategy successfully generated anti-tumor immunity in a microsatellite stable colon cancer model, stimulated T-cell infiltration, and holds promise as a combination immunotherapy for treating advanced and metastatic colorectal cancer.

Combination Immunotherapy With LIGHT and Interleukin-2 Increases CD8 Central Memory T-Cells In Vivo.

BACKGROUND: The generation of long-term durable tumor immunity and prolonged disease-free survival depends on the ability to generate and support CD8+ central memory T-cells. Microsatellite-stable colon cancer is resistant to currently available immunotherapies; thus, development of novel mechanisms to increase both lymphocyte infiltration and central memory formation are needed to improve outcomes in these patients. We have previously demonstrated that both interleukin-2 (IL-2) and LIGHT (TNFSF14) independently enhance antitumor immune responses and hypothesize that combination immunotherapy may increase the CD8+ central memory T-cell response. METHODS: Murine colorectal cancer tumors were established in syngeneic mice. Tumors were treated with control, soluble, or liposomal IL-2 at established intervals. A subset of animal tumors overexpressed tumor necrosis superfamily factor LIGHT (TNFSF14). Peripheral blood, splenic, and tumor-infiltrating lymphocytes were isolated for phenotypic studies and flow cytometry. RESULTS: Tumors exposed to a combination of LIGHT and IL-2 experienced a decrease in tumor size compared with IL-2 alone that was not demonstrated in wild-type tumors or between other treatment groups. Combination exposure also increased splenic central memory CD8+ cells compared with IL-2 administration alone, while not increasing tumor-infiltrating lymphocytes. In the periphery, the combination enhanced levels of circulating CD8 T-cells and central memory T-cells, while also increasing circulating T-regulatory cells. CONCLUSIONS: Combination of IL-2, whether soluble or liposomal, with exposure to LIGHT results in increased CD8+ central memory cells in the spleen and periphery. New combination immunotherapy strategies that support both effector and memory T-cell functions are critical to enhancing durable antitumor responses and warrant further investigation.

Induction of Antigen-Independent Proliferation of Regulatory T-Cells by TNF Superfamily Ligands OX40L and GITRL.

TNF receptor superfamily comprises many T-cell costimulatory receptors, including TNFRSF1, TNFRSF2, TNFRSF4 (OX40), TNFRSF9 (4-1BB), TNFRSF18 (GITR), and TNFRSF7 (CD27). Signaling through these costimulatory stimulatory receptors can promote conventional T-cell (Tconv) proliferation, and effector functions in an antigen-dependent manner. Thus, agonistic antibodies and ligands for OX40, 4-1BB, GITR, and CD27 have been tested for inducing T-cell-mediated antitumor responses in several cancers. However, recently emerging reports show critical role for TNFR signaling in regulatory T-cell (Treg) differentiation and expansion, which might suppress effector T-cell proliferation and functions. Here, we show preferential over expression of TNFR2, OX40, 4-1BB, and GITR in Treg cells over Tconv cells, and the ability of OX40L and GITRL to induce selective proliferation of Treg cells, but not Tconv cells, in an antigen-independent manner. We describe the standard protocols used for Affymetrix gene expression profiling, T-cell isolation, and Cell Trace Violet-based cell proliferation assay.

Epidemiology of out-of-Hospital Cardiac Arrests, knowledge of cardiovascular disease and risk factors in a regional setting in India: The Warangal Area out-of-hospital Cardiac Arrest Registry (WACAR).

OBJECTIVE: Out-of-Hospital Cardiac Arrest (OHCA) is a global public health problem. There is inadequate data on OHCA in India. The Warangal Area out-of-hospital Cardiac Arrest Registry (WACAR) was planned to understand OHCA in a regional setting in India. METHODS: WACAR is a prospective one-year observational cohort study of OHCA in the Warangal area, Telangana, India. The study included 814 subjects of OHCA of presumed cardiac etiology brought to the Mahatma Gandhi Memorial Hospital during January 1, 2018, and December 31, 2018. The data collected included; standard Utstein variables with additional data on clinical characteristics (modified Utstein template). RESULTS: The majority of OHCA subjects were male with a median age of 60 years, and mostly occurring in residential locations within 1 h of onset of symptoms. Individuals with knowledge of CVD risk factors were more likely to report symptoms before OHCA. Data on resuscitation characteristics were inadequate. CONCLUSIONS: The WACAR study provides baseline data regarding OHCA in a regional setting in India. The study demonstrated barriers involving data collection, patient knowledge of CVD risk factors and disease, and access to healthcare, which; impacted the data registry.

Post-translational modifications contribute to neoepitopes in Type-1 diabetes: Challenges for inducing antigen-specific tolerance.

Type-1 Diabetes (T1D) is the major autoimmune disease affecting the juvenile population in which insulin-producing pancreatic ß-cells are destroyed by self-reactive T-cells and B-cells. Emerging studies have identified the presence of autoantibodies and altered T-cell reactivity against several autoantigens in individuals who are at risk of developing T1D even before the clinical onset of diabetes. Whilst these findings could lead to the development of predictive biomarkers for early diagnosis, growing evidence on the generation of neoepitopes, epitope spreading and diverse antigen repertoire in T1D poses a major challenge for developing approaches to induce antigen-specific tolerance. Mechanisms of neoepitope generation include post-translational modifications of existing epitopes, aberrant translational products, peptide fusion, and differences in MHC binding registers. Here, we focus our discussion on how post-translational modifications can give rise to immunogenic neoepitopes in T1D and present our perspective on how it could affect the development of therapeutic approaches to induce antigen-specific tolerance.

Oncolytic adenovirus encoding LIGHT (TNFSF14) inhibits tumor growth via activating anti-tumor immune responses in 4T1 mouse mammary tumor model in immune competent syngeneic mice.

LIGHT, also known as tumor-necrosis factor (TNF) superfamily member 14 (TNFSF14), is predominantly expressed on activated immune cells and some tumor cells. LIGHT is a pivotal regulator both for recruiting and activating immune cells in the tumor lesions. In this study, we armed human telomerase reverse transcriptase (TERT) promoter controlled oncolytic adenovirus with LIGHT to generate rAd.Light. rAd.Light effectively transduced both human and mouse breast tumor cell lines in vitro, and expressed LIGHT protein on the surface of tumor cells. Both rAd.Null, and rAd.Light could replicate in human breast cancer cells, and produced cytotoxicity to human and mouse mammary tumor cells. rAd.Light induced apoptosis resulting in tumor cell death. Using a subcutaneous model of 4T1 cells in BALB/c mice, rAd.Light was delivered intratumorally to evaluate the anti-tumor responses. Both rAd.Light and rAd.Null significantly inhibited the tumor growth, but rAd.Light produced much stronger anti-tumor effects. Histopathological analysis showed the infiltration of T lymphocytes in the tumor tissues. rAd.Light also induced stronger cellular apoptosis than rAd.Null in the tumors. Interestingly, on day 15, compared to rAd.Null, there was a significant reduction of Tregs following rAd.Light treatment. rAd.Light significantly increased Th1 cytokine interleukin (IL)-2 expression, and reduced Th2 cytokines expression, such as transforming growth factor ß (TGF-ß) and IL-10 in the tumors. These results suggest rAd.Light induced activation of anti-tumor immune responses. In conclusion, rAd.Light produced anti-tumor effect in a subcutaneous model of breast cancer via inducing tumor apoptosis and evoking strong anti-tumor immune responses. Therefore, rAd.Light has great promise to be developed as an effective therapeutic approach for the treatment of breast cancer.

Cancer immunotherapy with check point inhibitor can cause autoimmune adverse events due to loss of Treg homeostasis.

Regulatory T-cells (Tregs) can facilitate immune evasion by tumor cells by dampening anti-tumor immunity. Reduced Teff/Treg ratio and enhanced Treg functional activity have been observed in patients suffering from different types of cancers, and attenuated Treg numbers/functions can serve as prognostic indicators. Normally, Tregs play an essential role in the maintenance of immune tolerance and prevention of autoimmunity. The most common immune checkpoint blockers (ICB) targeting co-inhibitory receptors such as anti-CTLA4 (ipilimumab and tremelimumab) and anti-PD1 (pembrolizumab and nivolumab)/anti-PD-L1 (atezolizumab) have achieved unprecedented success in cancer treatment by facilitating an effective anti-tumor immune response, at least in part, by blocking Treg mediated immunosuppression. While ICBs have shown remarkable success in cancer immunotherapy, immune-related adverse events (IRAEs) arising from ICB have forced consideration of ways to maintain immune homeostasis post ICB treatment. Preclinical models of IRAEs have shown a negative correlation between Treg numbers and IRAEs. Therefore, understanding the "ying-yang" role of Tregs in the regulation of autoimmunity and anti-tumor immunity is critical to provoking an effective anti-tumor response while maintaining immune homeostasis. Studies aimed at developing effective approaches to minimize IRAEs without compromising anti-tumor immunity are underway. Herein, we discuss 1) the critical role of key co-inhibitory receptors on Treg homeostasis and tumor tolerance; 2) how co-receptor blockade by cancer immunotherapy can lead to autoimmune adverse events; and 3) recently emerging management strategies to minimize autoimmune adverse events arising from ICB.

Vemurafenib may overcome TNF-related apoptosis-inducing ligand (TRAIL) resistance in anaplastic thyroid cancer cells.

PURPOSE: Anaplastic thyroid cancer (ATC) is rare but with poor prognosis. TRAIL can selectively induce apoptosis in cancer cells; however, resistance is quite common. Aim of our study was to evaluate TRAIL-induced apoptosis in ATC-derived cell lines, in vitro and in vivo, and the effect of combination with tyrosine kinase inhibitors (TKIs) selective for BRAF (vemurafenib) or Akt (MK-2206). METHODS: Four ATC-derived cell lines were used: C643, CAL62, HTh7, with activating mutation of RAS and copy gain of PI3K (HTh7) and, 8505C with activating mutation of BRAF. Cells were treated with TRAIL alone or in combination with vemurafenib or MK-2206. The pro-apoptotic effect of TRAIL alone or combined with TKIs was, also, evaluated in two mouse xenograft models (HTh7 and 8505C). RESULTS: C643, CAL62, and HTh7 cells were sensitive to TRAIL-induced apoptosis, whereas 8505C cells were resistant. Both in vitro and in vivo vemurafenib was able to increase the TRAIL-induced apoptosis in 8505C cells causing a slower tumor growth in 8505C xenograft compared to placebo, while MK-2206 did not have any additive effect on TRAIL treatment in HTh7 model. CONCLUSIONS: TRAIL is a promising therapeutic agent in ATC and in case of resistance vemurafenib may be a valid complementary therapy.

OX40L-JAG1-Induced Expansion of Lineage-Stable Regulatory T Cells Involves Noncanonical NF-κB Signaling.

Foxp3+T regulatory cells (Tregs) control autoimmune response by suppressing proliferation and effector functions of self-reactive Foxp3-CD4+/CD8+ T cells and thereby maintain the critical balance between self-tolerance and autoimmunity. Earlier, we had shown that OX40L-JAG1 cosignaling mediated through their cognate receptors OX40 and Notch3 preferentially expressed on murine Tregs can selectively induce their proliferation in the absence of TCR stimulation. However, the differential molecular mechanisms regulating TCR-independent versus TCR-dependent Treg proliferation and lineage stability of the expanded Tregs remained unknown. In this study, we show that OX40L-JAG1 treatment induced TCR-independent proliferation of Tregs in the thymus and periphery. The use of Src kinase inhibitor permitted us to demonstrate selective inhibition of TCR-dependent T cell proliferation with little to no effect on OX40L-JAG1-induced TCR-independent Treg expansion in vitro, which was critically dependent on noncanonical NF-κB signaling. OX40L-JAG1-expanded Tregs showed sustained lineage stability as indicated by stable demethylation marks in Treg signature genes such as Foxp3, Il2ra, Ctla4, Ikzf2, and Ikzf4. Furthermore, OX40L-JAG1 treatment significantly increased CTLA4+ and TIGIT+ Tregs and alleviated experimental autoimmune thyroiditis in mice. Relevance of our findings to humans became apparent when human OX40L and JAG1 induced TCR-independent selective expansion of human Tregs in thymocyte cultures and increased human Tregs in the liver tissue of humanized NSG mice. Our findings suggest that OX40L-JAG1-induced TCR-independent Treg proliferation is a conserved mechanism that can be used to expand lineage-stable Tregs to treat autoimmune diseases.

An Oncolytic Adenovirus Targeting Transforming Growth Factor ß Inhibits Protumorigenic Signals and Produces Immune Activation: A Novel Approach to Enhance Anti-PD-1 and Anti-CTLA-4 Therapy.

In an effort to develop a new therapy for cancer and to improve antiprogrammed death inhibitor-1 (anti-PD-1) and anticytotoxic T lymphocyte-associated protein (anti-CTLA-4) responses, we have created a telomerase reverse transcriptase promoter-regulated oncolytic adenovirus rAd.sT containing a soluble transforming growth factor receptor II fused with human IgG Fc fragment (sTGFßRIIFc) gene. Infection of breast and renal tumor cells with rAd.sT produced sTGFßRIIFc protein with dose-dependent cytotoxicity. In immunocompetent mouse 4T1 breast tumor model, intratumoral delivery of rAd.sT inhibited both tumor growth and lung metastases. rAd.sT downregulated the expression of several transforming growth factor ß (TGFß) target genes involved in tumor growth and metastases, inhibited Th2 cytokine expression, and induced Th1 cytokines and chemokines, and granzyme B and perforin expression. rAd.sT treatment also increased the percentage of CD8+ T lymphocytes, promoted the generation of CD4+ T memory cells, reduced regulatory T lymphocytes (Tregs), and reduced bone marrow-derived suppressor cells. Importantly, rAd.sT treatment increased the percentage of CD4+ T lymphocytes, and promoted differentiation and maturation of antigen-presenting dendritic cells in the spleen. In the immunocompetent mouse Renca renal tumor model, similar therapeutic effects and immune activation results were observed. In the 4T1 mammary tumor model, rAd.sT improved the inhibition of tumor growth and lung and liver metastases by anti-PD-1 and anti-CTLA-4 antibodies. Analysis of the human breast and kidney tumors showed that a significant number of tumor tissues expressed high levels of TGFß and TGFß-inducible genes. Therefore, rAd.sT could be a potential enhancer of anti-PD-1 and anti-CTLA-4 therapy for treating breast and kidney cancers.

MADD silencing enhances anti-tumor activity of TRAIL in anaplastic thyroid cancer.

ATC is an aggressive disease with limited therapeutic options due to drug resistance. TRAIL is an attractive anti-cancer therapy that can trigger apoptosis in a cancer cell-selective manner. However, TRAIL resistance is a major clinical obstacle for its use as a therapeutic drug. Previously, we demonstrated that MADD is a cancer cell pro-survival factor that can modulate TRAIL resistance. However, its role, if any, in overcoming TRAIL resistance in ATC is unknown. First, we characterized ATC cell lines as either TRAIL resistant, TRAIL sensitive or moderately TRAIL sensitive and evaluated MADD expression/cellular localization. We determined the effect of MADD siRNA on cellular growth and investigated its effect on TRAIL treatment. We assessed the effect of combination treatment (MADD siRNA and TRAIL) on mitochondrial membrane potential (MMP) and reactive oxygen species (ROS) levels. The effect of combination treatment on tumor growth was assessed in vivo. We found increased levels of MADD in ATC cells relative to Nthy-ori 3-1. MADD protein localizes in the cytosol (endoplasmic reticulum and Golgi body) and membrane. MADD knockdown resulted in spontaneous cell death that was synergistically enhanced when combined with TRAIL treatment in otherwise resistant ATC cells. Combination treatment resulted in a significant reduction in MMP and enhanced generation of ROS indicating the putative mechanism of action. In an orthotopic mouse model of TRAIL-resistant ATC, treatment with MADD siRNA alone reduced tumor growth that, when combined with TRAIL, resulted in significant tumor regressions. We demonstrated the potential clinical utility of MADD knockdown in sensitizing cells to TRAIL-induced apoptosis in ATC.

Loss of MADD expression inhibits cellular growth and metastasis in anaplastic thyroid cancer.

Anaplastic Thyroid Cancer (ATC) is an aggressive malignancy with limited therapeutic options and dismal patient survival. We have previously shown MADD to be differentially overexpressed in multiple cancer histologies and to contribute to tumor cell growth and survival. Therefore, we targeted MADD by gene silencing, explored its effect on cellular proliferation and metastases and examined its therapeutic potential in an orthotopic ATC model in athymic nude mice. When compared to untreated control and scramble siRNA, MADD siRNA treatment inhibited the proliferative capacity of 8505C, C643 and HTH7 cells in vitro and 8505C-derived-orthotopic tumor growth in vivo. MADD ablation caused a significant reduction in cellular migration and invasion potential; clonogenic capacity; as well as, mitochondrial length and potential in vitro. This MADD siRNA-induced anti-migratory/invasive effect corresponded with inhibition of epithelial-mesenchymal transition (EMT) and Wnt signaling. Mechanistically, MADD siRNA inhibited TNFα induced activation of pERK, pGSK3ß and ß-catenin, suggesting that MADD knockdown might exert its anti-migratory/invasive effects, by blocking TNFα/ERK/GSK3ß axis. MADD siRNA can inhibit ß-catenin nuclear translocation and consequently, the expression of its target genes in ATC cells. In in vivo experiments, along with tumor regression, MADD siRNA treatment also decreased evidence of lung metastases. Immunohistochemically, MADD siRNA-treated tumor tissues exhibited a reduction in Ki67 and N-Cadherin expression, and an increase in E-Cadherin expression. In conclusion, we show the crucial role of MADD in ATC tumorigenesis and metastasis and its potential implications as a molecular target for ATC therapy.

Molecular aberrations and signaling cascades implicated in the pathogenesis of anaplastic thyroid cancer.

Anaplastic Thyroid Cancer (ATC) accounts for >40% thyroid cancer-related deaths and has a dismal prognosis. In the past decade, significant efforts have been made towards understanding the pathogenesis of this disease and developing novel therapeutics. Unfortunately, effective treatment is still lacking and a more thorough understanding of ATC pathogenesis may provide new opportunities to improve ATC therapeutics. This review provides insights into ATC clinical presentation and pathology, and the putative role of genetic aberrations and alterations in molecular signaling pathways in ATC pathogenesis. We reviewed prevalent mutations, chromosomal abnormalities and fusions, epigenetic alterations and dysregulations in ATC, and highlighted several signaling cascades which appeared to be integral to ATC pathogenesis. Moreover, these features offer insights into de-differentiated, aggressive and drug-resistant phenotype of ATC, and thus may help in exploring potential new molecular targets for developing novel therapeutics.

Critical role of OX40 signaling in the TCR-independent phase of human and murine thymic Treg generation.

Regulatory T cells (Tregs) play a pivotal role in immune-tolerance, and loss of Treg function can lead to the development of autoimmunity. Natural Tregs generated in the thymus substantially contribute to the Treg pool in the periphery, where they suppress self-reactive effector T cells (Teff) responses. Recently, we showed that OX40L (TNFSF4) is able to drive selective proliferation of peripheral Tregs independent of canonical antigen presentation (CAP-independent) in the presence of low-dose IL-2. Therefore, we hypothesized that OX40 signaling might be integral to the TCR-independent phase of murine and human thymic Treg (tTreg) development. Development of tTregs is a two-step process: Strong T-cell receptor (TCR) signals in combination with co-signals from the TNFRSF members facilitate tTreg precursor selection, followed by a TCR-independent phase of tTreg development in which their maturation is driven by IL-2. Therefore, we investigated whether OX40 signaling could also play a critical role in the TCR-independent phase of tTreg development. OX40-/- mice had significantly reduced numbers of CD25-Foxp3low tTreg precursors and CD25+Foxp3+ mature tTregs, while OX40L treatment of WT mice induced significant proliferation of these cell subsets. Relative to tTeff cells, OX40 was expressed at higher levels in both murine and human tTreg precursors and mature tTregs. In ex vivo cultures, OX40L increased tTreg maturation and induced CAP-independent proliferation of both murine and human tTregs, which was mediated through the activation of AKT-mTOR signaling. These novel findings show an evolutionarily conserved role for OX40 signaling in tTreg development and proliferation, and might enable the development of novel strategies to increase Tregs and suppress autoimmunity.