Suppressor T Cells Research Articles

Probiotics: An Alternative Therapeutic Strategy for Covid-19

ABSTRACT: The COVID- 19 pandemic has made the scientists today all around the globe to look for its specific prevention and treatment modalities. The disease presents itself as asymptomatic to mild to severe respiratory symptoms along with lesser common gastrointestinal symptoms of diarrhea, nausea, and vomiting. The situation worsens due to lack of precise treatment strategy. The Healthcare system is being overwhelmed, emphasizing on the need to look for alternate supportive therapy that can not only enhance the immune status of people worldwide but at the same time, ensure better prognosis. The relationship between the gut microbiota and upper and lower respiratory tract viral infections are well studied. Oral administration of probiotic microorganisms of genera Lactobacillus, Bifidobacterium and Bacillusin mice suffering from influenza infection have shown increased TNFα, IFN-γ and NK cell responses along with the production of anti-Influenza IgG. At the same time they have shown immunomodulation by producing anti-inflammatory cytokines as well as cytotoxic T-cells and T-suppressor cells. Hence, probiotic strains of generaLactobacillus, Bifidobacterium and Bacillushave shown a probability to be used as preventive and therapeutic agents for SARS- CoV-2.

Cellular Immunoprofile of Peritoneal Environment During a HIPEC Procedure.

We characterized the peritoneal immune cellular profile during cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC) in this pilot study. We prospectively performed flow cytometric analysis of peritoneal fluid collected at laparotomy and during HIPEC at 0, 30, 60, and 90min. Analysis consisted of standard flow cytometric leukocyte gating and the use of antibodies for stem cells, B lymphocytes, T-helper, T-suppressor, and natural killer (NK) cells. The mean peritoneal carcinomatosis index (PCI) score was 19.8 ± 11.5 (median 19). Twelve patients had a completeness of cytoreduction (CCR) score of 0-1, and three patients had a CCR score of ≥ 2 (20%). The proportion of peritoneal NK cells remained stable (p = 0.655) throughout perfusion. The CD4/CD8 ratio (p = 0.019) and granulocyte/lymphocyte ratio (p = 0.018) evolved during cytoreduction, with no further change during HIPEC. Two distinct temporal patterns of peritoneal T lymphocytes became evident (the 'high' and 'low' CD4/CD8 ratio groups) and patients maintained their high versus low peritoneal CD4/CD8 ratio status throughout the duration of HIPEC. High CD4/CD8 was associated with longer cytoreduction (p = 0.019) and borderline higher PCI score (p = 0.058). No association was identified with age (p = 0.131), sex (p = 1.000), CCR status (p = 0.580), occurrence of complication (p = 0.282), or ascites volume (p = 0.713). The cellular immunoprofile of peritoneal fluid during HIPEC is stable but changes during cytoreduction. Two distinct immune groups emerged, based on CD4/CD8 ratios in the peritoneal perfusate. Further studies are warranted to evaluate peritoneal immunity and the clinical significance of novel peritoneal immune phenotype.

Status of Piglets’ Cellular Immunity in the Early Postnatal Period

The results of studying piglets' cellular immunity in the postnatal period in an industrial pig-farming system have been reported. It is ascertained that the cellular immunity in piglets before colostrum intake is characterized by leukocytopenia, lymphocytopenia, T- and B-lymphocyte deficiencies and high ratios of theophylline-resistant (T-helpers) to theophylline-sensitive (T-suppressors) T cells, indicating the low suppressive activity of T lymphocytes. In 1-day-old piglets after colostrum intake and during the whole period of their growing under the sows, the increased counts of white-blood cells and lymphocytes, the T- and B-lymphocyte absolute counts, and T-helper cells, along with a lower count of T-suppressor cells and low T-to-B-cell ratios, indicating the predominant mechanisms of specific cellular defense, were recorded. A reduction in the counts of white-blood cells, lymphocytes, and T- and B-lymphocytes in piglets on the 14th day of life, when compared to the parameters measured on the seventh day of life, is caused by the decline in these cell’s supply via sow milk. A subsequent increase is associated with the activation of the piglets’ own immune system function, whose development is dependent on the effects of microbial contamination within the mucous membranes and the skin.

Allogeneic bone marrow derived mesenchymal stem cells outperform the autologous in modulating dendritic cells isolated from type 1 diabetic patients

Background & Aim Dendritic cells (DCs) have been implicated in the pathogenesis of type 1 diabetes mellitus (T1DM) and have potential as immunotherapeutic agents. The inhibition of DCs profile and function is part of the multi-level immunomodulatory properties displayed by human Mesenchymal Stem Cells (MSCs). Due to their potent immunoregulatory and immunomodulatory functions, MSCs have emerged as a therapeutic regimen in the management of many diseases that have no effective treatment, including T1DM. It has been shown that in T1DM patients DCs respond in terms of maturation, activation, and phenotype when co-cultured with autologous and allogeneic Bone Marrow derived MSCs (BM-MSC). In the recent study, the effect of autologous BM-MSCs in comparison with the allogeneic BM-MSCs co-cultured with monocyte-derived DCs isolated from TIDM patients was investigated for the first time. Methods, Results & Conclusion Methods Autologous and allogeneic BM-MSCs were isolated from healthy donors and T1DM patients. Then, morphology and surface markers expression were analyzed. Mature DCs (mDCs) were differentiated from CD14+ cells, obtained from newly diagnosed T1DM patients, pulsed with antigen Glutamic Acid Decarboxylase (GAD65) and co-cultured with BM-MSCs. the expression of co-stimulatory molecules and maturation markers were evaluated by flow cytometery. The level of anti-inflammatory cytokines was measured by ELISA. Autologous CD14- cells and GAD65 pulsed mDCs were co-cultured and IFN-γ ELISPOT responses were performed. Secreted level of IL-17 was measured Result autologous and allogeneic BM-MSCs have a comparable effect on GAD65 pulsed mature mDCs in terms of phenotype and maturation marker expression. Interestingly, the secretion levels of (IL-10, IL-6 and TGF-B) increased significantly in the allogeneic BM-MSCs when co-cultured with GAD65 pulsed mDCs. GAD65 pulsed-mDCs/T-cells showed decreased IFN-γ production when co-cultured with BM-MSCs. Moreover, the level of IL-17 secretion declined significantly in the allogeneic BM-MSCs compared to the autologous cells. Conclusion This research demonstrated in vitro the potent immunomodulatory effect of allogeneic BM-MSCs on pancreatic islet antigen specific T-Cells in newly-diagnosed T1DM patients through the induction of DCs’ tolerogenic function. These DCs can contribute to the suppressing T-cell mediated immunity and the promotion of anti-inflammatory responses exerted by BM-MSCs.

MiR130b from Schlafen4+ MDSCs stimulates epithelial proliferation and correlates with preneoplastic changes prior to gastric cancer

The myeloid differentiation factor Schlafen4 (Slfn4) marks a subset of myeloid-derived suppressor cells (MDSCs) in the stomach during Helicobacter-induced spasmolytic polypeptide-expressing metaplasia (SPEM).ObjectiveTo identify the gene products expressed by Slfn4+-MDSCs...

Correlation of plasma exosomal microRNAs with the efficacy of immunotherapy in EGFR/ALK wild-type advanced non-small cell lung cancer

BackgroundImmunotherapy has become an important treatment option for patients with advanced non-small cell lung cancer (NSCLC). At present, none of these existing biomarkers can effectively stratify true responders and there...

Abstract 1012: Selective estrogen receptor downregulators and immune checkpoint inhibitors in breast cancer immunotherapy

Abstract Breast cancers (BC) with expression of estrogen receptor-alpha (ERα) occur in more than 70% of newly-diagnosed patients in the U.S. Endocrine therapy with antiestrogens or aromatase inhibitors is an important intervention for BCs that express ERα, and it remains one of the most effective targeted treatments. However, substantial numbers of patients with localized disease, and almost all patients with metastatic BC, become resistant to current endocrine therapies. ERα is present in most resistant BCs, and in many of these its activity continues to regulate BC growth. Fulvestrant represents a class of ERα antagonists that elicit selective ER downregulation (SERDs), an action that helps overcome several resistance mechanisms. Unfortunately, full antitumor efficacy of fulvestrant is limited by its poor bioavailability in clinic. We have designed and tested a new generation of steroid-like SERDs. Using ERα-positive BC cells in vitro, we find that these compounds suppress ERα protein levels with efficacy similar to fulvestrant. Moreover, these new SERDs markedly inhibit ERα-positive BC cell proliferation in vitro even in the presence of estradiol-17β. In vivo, SERD-128 significantly inhibits tumor growth in MCF-7 xenograft models in a dose-dependent manner (P<0.001). Further, our findings show that new SERDs as well as fulvestrant also interact with immune cells expressing ER such as myeloid-derived suppressor cells (MDSC), dendritic cells and T-lymphocytes. Importantly, MDSCs act to protect tumors from immune recognition and elimination in vivo. Since a fraction of triple-negative breast cancers (TNBC; ERα-/PR-/HER2-) but not other BC subtypes respond to immune checkpoint inihbitors (ICIs), we assessed the antitumor effects of SERDs in murine TNBCs in immune-competent, syngeneic mouse models. Notably, SERD treatment induced a blockade of MDSC populations in tumors and rendered TNBCs in vivo more susceptible to ICIs, thereby leading to enhanced tumor killing. Since monotherapy with checkpoint inhibitors has not been effective for most TNBCs, combination therapies with SERDs that enhance immune recognition may increase immunotherapy responses in TNBC and improve patient survival. In addition, SERDs combined with ICIs may potentially benefit patients with other BC subtypes that are unresponsive to current endocrine treatment strategies. [Funded by Tower Cancer Research Foundation-Jessica M. Berman Fund, NCI U54 CA-14393 and UCLA Innovation Fund]. Citation Format: Diana C. Márquez-Garban, Gang Deng, Begonya Comin-Anduix, Alejandro J. Garcia, Emelyine Diers, Gaoyuan Ma, Nalo Hamilton, Michael E. Jung, Richard J. Pietras. Selective estrogen receptor downregulators and immune checkpoint inhibitors in breast cancer immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1012.

Post-transplantation cyclophosphamide prevents graft-versus-host disease by inducing alloreactive T cell dysfunction and suppression.

Post-transplantation cyclophosphamide (PTCy) recently has had a marked impact on human allogeneic hematopoietic cell transplantation (HCT). Yet, our understanding of how PTCy prevents graft-versus-host disease (GVHD) largely has been extrapolated from major histocompatibility complex (MHC)-matched murine skin allografting models that were highly contextual in their efficacy. Herein, we developed a T-cell-replete, MHC-haploidentical, murine HCT model (B6C3F1→B6D2F1) to test the putative underlying mechanisms: alloreactive T-cell elimination, alloreactive T-cell intrathymic clonal deletion, and suppressor T-cell induction. In this model and confirmed in four others, PTCy did not eliminate alloreactive T cells identified using either specific Vβs or the 2C or 4C T-cell receptors. Furthermore, the thymus was not necessary for PTCy's efficacy. Rather, PTCy induced alloreactive T-cell functional impairment which was supported by highly active suppressive mechanisms established within one day after PTCy that were sufficient to prevent new donor T cells from causing GVHD. These suppressive mechanisms included the rapid, preferential recovery of CD4+CD25+Foxp3+ regulatory T cells, including those that were alloantigen-specific, which served an increasingly critical function over time. Our results prompt a paradigm-shift in our mechanistic understanding of PTCy. These results have direct clinical implications for understanding tolerance induction and for rationally developing novel strategies to improve patient outcomes.

672 Pramlintide produces immunomodulatory effects on myeloid-derived suppressor cells and T-cells in squamous cell carcinoma in-vivo

Cutaneous squamous cell carcinoma (cuSCC) accounts for 15-20% of skin cancers. Treatment of cuSCC with pramlintide, a synthetic analog of the hormone amylin, and an FDA-approved anti-diabetic drug, is currently under investigation in mouse models and human clinical trials in our lab. In cancer cells, pramlintide inhibits ΔNp63 and tumor cell glycolysis, resulting in cell death and tumor regression. In order to investigate the potential use of pramlintide in combination therapies, we aimed to study the immunomodulatory effect of pramlintide in a mouse model of UV-induced cuSCC, as well as its effect on human T cells in vitro. To induce cuSCC, SKH-1 hairless mice chronically irradiated with solar simulated light over 3 months. When at least one tumor reached >4mm of diameter, mice were then treated with pramlintide vs. vehicle over 10 days. Skin-draining lymph nodes, spleen and tumors were harvested for immunophenotyping of the T cell and myeloid compartments by FACS. While the proportion of CD103+ dendritic cells and CD3+ T cells remained constant after pramlintide treatment, a significant decrease in the proportion of both monocytic and granulocytic myeloid-derived suppressor cells (m-MDSCs and g-MDSCs) was observed relative to vehicle treated mice (p< 0.001, p< 0.01, respectively). Gene expression of Mtor and Stat3 were downregulated in m-MDSCs after treatment with pramlintide for 24h, suggesting pramlintide inhibits mTOR pathway in this population. In addition, purified human CD3+ T cells activated in the presence of pramlintide exhibited a time-dependent increase in intracellular and secreted IFN-γ relative to controls. Therefore, pramlintide presents immunomodulatory effects based on both a reduction in myeloid-dependent suppression and a direct stimulatory effect on T cells that would culminate in superior anti-tumor T cell responses that may augment immunotherapeutic approaches for the treatment of cuSCC. The next steps include a trial of combined anti-PD1 and pramlintide therapy.

IMMUNOLOGICAL MARKERS OF CHILDREN HEALTH PROBLEMS LIVING IN THE CONDITIONS OF ATMOSPHERIC AIR POLLUTION BY ALUMINUM

We analyzed the characteristics of the immunoregulatory parameters of the child population (94 people) aged 5 to 10 years exposed to aluminum. The control group included 45 children, matched by age and sex, living in areas not exposed to aluminum. The study consisted of determining the content of IgG specific to aluminum, total IgE (hypersensitivity indicators) and phagocytic-active cells. A study of CD-markers of cell differentiation and intracellular markers for assessing the apoptosis system (absolute and relative suppressor T-cell receptors CD127–, Bax, anti-apoptotic protein Bcl-2 and proapoptotic cell death receptor CD95+) was performed. As a result of the research, it was reliably established that in the examined child population there are violations of the cellular immunity, which manifest themselves in a decrease in phagocytic activity by the criterion of absolute phagocytosis (42 per cent), relative phagocytosis (56 per cent) and phagocytic number (75 per cent) (for example, decrease in phagocytic activity of cells compared with control was 1.2-1.5 times), activation of absolute and relative suppressor T-cell receptors CD127–, Bax deficiency, antiapoptotic protein Bcl -2 and the proapoptotic cell death receptor CD95+ (p &lt; 0.05) responsible for apoptosis, relative to the reference values. There is a significant increase compared with the norm of specific IgG to aluminum in 44 per cent of children of the observed group and an increase in the level of total IgE by more than 1.4 times compared to the control group (p &lt; 0.05)

Orthotopic Transplantation of Syngeneic Lung Adenocarcinoma Cells to Study PD-L1 Expression

The use of mouse models is indispensable for studying the pathophysiology of various diseases. With respect to lung cancer, several models are available, including genetically engineered models as well as transplantation models. However, genetically engineered mouse models are time-consuming and expensive, whereas some orthotopic transplantation models are difficult to reproduce. Here, a non-invasive intratracheal delivery method of lung tumor cells as an alternative orthotopic transplantation model is described. The use of mouse lung adenocarcinoma cells and syngeneic graft recipients allows studying tumorigenesis under the presence of a fully active immune system. Furthermore, genetic manipulations of tumor cells before transplantation makes this model an attractive time-saving approach to study the impact of genetic factors on tumor growth and tumor cell gene expression profiles under physiological conditions. Using this model, we show that lung adenocarcinoma cells express increased levels of the T-cell suppressor programmed death-ligand 1 (PD-L1) when grown in their natural environment as compared to cultivation in vitro.

More Than a Tumor Marker…A Potential Role for Alpha-Feto Protein in Inflammatory Bowel Disease.

Human alpha-fetoprotein (hAFP) is a glycoprotein derived from the gut entoderm and expressed sequentially by cells of the yolk sac, fetal liver, and gastrointestinal tract. By adulthood, serum levels of alpha-fetoprotein (AFP) are undetectable in healthy, nonpregnant adults. Despite the clinical utilities of AFP monitoring in pregnancy and malignancy, much remains to be determined regarding its potential physiological functions. We focused on literature related to AFP's immunoregulatory role and its ability to modulate disease activity both in animal models of autoimmune disorders and in human clinical studies. Evidence suggests that AFP plays an important role in immunoregulation by inducing T-cell suppressor activity, downregulating dendritic-like cell antigen expression, and impairing the function of macrophages. Studies evaluating AFP and its effects in rodent models of autoimmune diseases have shown that AFP is associated with downregulation of inflammation. Observations in studies of pregnant patients with immune-mediated inflammatory diseases have also described potential correlations between AFP expression and disease activity during different stages of pregnancy and postpartum. We propose further prospective evaluations of AFP expression during pregnancy in inflammatory bowel disease patients to further correlate with disease activity and consider the potential of AFP as a novel therapeutic agent.

T-Cell Lymphopenia in Patients with Advanced Thyroid Carcinoma Is Associated with Poor Prognosis.

Aggressive forms of thyroid carcinoma (TC) show an abundant infiltration of immune cells, and this correlates with prognosis. However, little is known about circulating immune cell levels in advanced TC. Investigate T-cell and myeloid-derived suppressor cell (MDSC) levels in peripheral blood of patients with advanced TC and correlate them with survival. T cells and MDSCs were quantified by flow cytometry in peripheral blood from nine patients with advanced TC and nine healthy volunteers. No significant differences in MDSC or regulatory T-cell levels were detected between patients with TC and healthy controls. CD3, CD4, and CD8 T-cell levels were significantly lower in patients with TC. CD3 and CD4 T-cell levels further decreased in patients with survival of less than 1 month. These data suggest that T-cell lymphopenia in patients with TC indicates an aggressive tumor behavior and might influence therapeutic choices in the future. Restoring T-cell levels may become a potential therapeutic option within the multitarget approaches.

The Importance of Correlation of T-helper and T-supressor Limfocitary Subpopulations – Indicators of Animals Immune Status

The scientific investigations reflected in this study present the research in dynamics of the activity of correlating T-helper and T-suppressor immunocompetent cells at the newborn calves in different age periods. In the scientific research is presented the main effector role of these indicators, regarding the importance of the immune system through the ability to synthesize lymphokines, etc. The researches reveal T-helper and T-suppressor level of lymphocytes at all research ages. Thus at 10 days the concentration of T-helper lymphocytes was 7.85±0.001 and 8.30±0.08; 7.57 ± 0.008 at the age of 20 and 30 days, compared to T-suppressor lymphocytes, which in these age groups was equal to 6.0 ± 0.08; 6.33 ± 0.08 and 6.0±0.08. The results of the investigations offer the possibility to understand that the correlation of some lymphocytary subpopulations of the newborn animal organism provides the possibility of installing a strong immunity and ensures the maintenance of the biochemical homeostasis of the organism.

The role of the T-helper/T-suppressor ratio in the adaptive immune response: a dynamical model

Recent experimental studies have suggested the ratio between T-helper and T-suppressor lymphocytes as an index of immunosuppression in HIV, cancer, immunosenescence and inflammatory and auto-immune diseases. However, a quantitative understanding of the impact of this ratio on the immune response has lagged behind data and its validity as a tool for prognostic monitoring or therapeutic target remains an open question. In this work, we use statistical physics and dynamical systems approaches to analyze the time-dependent response to an antigen, of a simplified model of the adaptive immune system, which comprises B, T-helper and T-suppressor lymphocytes. The model is remarkably robust against changes in the noise level and kinetic parameters, but it is very sensitive to changes in the ratio between T-helper and T-suppressor lymphocytes, exhibiting, in particular, a transition from a responsive to an immuno-suppressed phase, as the ratio is lowered below a critical value, which is in line with experiments. This result supports the validity of the T-helper/T-suppressor ratio as an index of immunosuppression and may provide a useful theoretical benchmark to interpret and compare experiments.

A CASE OF RECURRENT ASPIRATION PNEUMONIA AND PERSISTENT EOSINOPHILIA

Introduction Homozygous or compound heterozygous loss-of-function (LOF) mutations in CARMIL2 are associated with combined immunodeficiency disorder with a variable phenotypic presentation in 10 families (21 patients). Clinical manifestations include recurrent skin and lung infections, dermatitis, chronic diarrhea, esophagitis, and failure-to-thrive. Here we describe a case of immune deficiency associated with an apparently homozygous, novel variant c.1942delC (p.His648ThrfsX20) in the CARMIL2 gene (RLTPR). Case Description The patient presented with recurrent pneumonias from 6-29 months of age, 11 requiring hospitalization. Pneumonias and bronchiectasis were attributed to aspiration of liquids, confirmed on barium swallow. Whole exome sequencing identified an apparently homozygous pathogenic variant (c.1954delC, resulting in frameshift p.H648TfsX20) in CARMIL2 gene. Immune evaluation was significant for poor antibody response to 12 of 14 pneumococcal serotypes, absent lymphocyte proliferation to antigens (candida and tetanus) with reduced lymphocyte proliferation to mitogens (PHA and Con A), an excess of CD19+B cells (2769 cells/mcL), low-level EBV viremia (5806 copies), and persistent eosinophilia (1.82-6.18x10³/µL). Total immunoglobulin levels (IgG, IgM, IgA, IgE) and CD8+T-suppressor cell-, CD4+T-helper cell-, and CD56+NK cell-counts were within normal range. Discussion Here we report a case of combined immune deficiency with associated findings of aspiration, recurrent pneumonias, eosinophilia, and B-cell lymphocytosis with EBV viremia in a child with an apparently homozygous novel variant in the CARMIL2 gene. This case report provides further evidence that homozygous LOF mutations in CARMIL2 are associated with a combined immune defect with varied phenotypic features. Identification of this mutation may have prognostic value and will guide genetic counseling.

Development of MGD007, a gpA33 x CD3-Bispecific DART Protein for T-Cell Immunotherapy of Metastatic Colorectal Cancer.

We have developed MGD007 (anti-glycoprotein A33 x anti-CD3), a DART protein designed to redirect T cells to target gpA33 expressing colon cancer. The gpA33 target was selected on the basis of an antibody-based screen to identify cancer antigens universally expressed in both primary and metastatic colorectal cancer specimens, including putative cancer stem cell populations. MGD007 displays the anticipated-bispecific binding properties and mediates potent lysis of gpA33-positive cancer cell lines, including models of colorectal cancer stem cells, through recruitment of T cells. Xenograft studies showed tumor growth inhibition at doses as low as 4 μg/kg. Both CD8 and CD4 T cells mediated lysis of gpA33-expressing tumor cells, with activity accompanied by increases in granzyme and perforin. Notably, suppressive T-cell populations could also be leveraged to mediate lysis of gpA33-expressing tumor cells. Concomitant with CTL activity, both T-cell activation and expansion are observed in a gpA33-dependent manner. No cytokine activation was observed with human PBMC alone, consistent with the absence of gpA33 expression on peripheral blood cell populations. Following prolonged exposure to MGD007 and gpA33 positive tumor cells, T cells express PD-1 and LAG-3 and acquire a memory phenotype but retain ability to support potent cell killing. In cynomolgus monkeys, 4 weekly doses of 100 μg/kg were well tolerated, with prolonged PK consistent with that of an Fc-containing molecule. Taken together, MGD007 displays potent activity against colorectal cancer cells consistent with a mechanism of action endowed in its design and support further investigation of MGD007 as a potential novel therapeutic treatment for colorectal cancer. Mol Cancer Ther; 17(8); 1761-72. ©2018 AACR.

Abstract 5478: Targeting kynurenine pathway for the treatment of cisplatin-resistant lung cancer

Abstract We have found that increasing ROS (reactive oxygen species) level is a specific and yet common feature found in cisplatin resistant (CR) lung cancer cells. We also showed that manipulation of ROS levels can selectively killed CR cells. Here, we have further identified the underlying mechanism for increasing ROS and its relationship with metabolic reprogramming and immune evasion. CR cells no longer follow classic aerobic glycolysis (Warburg effect). They do not primarily utilize glucose, but rather consume amino acids such as glutamine and tryptophan for survival. CR cells take up twice as much L-[G-3H] glutamine (n=4, p&amp;lt;0.05) and tryptophan (TRP) (n=4, p&amp;lt;0.04) when compared to its parental counterpart. These fundamental understandings have led us to study another unique mechanism where we found that CR cells activate kynurenine pathway (TRP catabolism) when they encounter excessive oxidative stress in order to maintain a finite level of ROS for their growth and proliferation. Importantly, kynurenine (KYN) which is oxidized through indoleamine 2,3-dioxygenase (IDO) via kynurenine pathway, plays a key role in reprogramming naïve T-cells to immune suppressive regulatory T-cell (T-reg) phenotype. Inhibiting IDO using Epacadostat (Incyte Corp.), a known IDO inhibitor which is currently in phase 3 trial, led to elevated ROS and resulted in the demise of CR cells. ROS levels were increased (2-3X) more in resistant cells after Epacadostat treatment while no significant change occurred in parental cells. The ID50 dosage of parental cells was 2-4 fold more than their CR cell counterparts and no cytotoxicity was found in normal lung fibroblast (n=6; p&amp;lt;0.05). To further determine whether IDO correlated with ROS levels and sensitivity to Epacadostat, we inhibited IDO expressions in CR cell lines (ie. ALC and H460CR) using siRNA. Knocking down IDO enhanced ROS production and more importantly suppressed CR cells' growth which further implicates the important role of kynurenine pathway (KP) in proliferation of CR tumors. Moreover, the treatment of knocked down cells with Epacadostat did not result in further cell death, indicating the specificity of this compound for the IDO enzyme. FoxP3, a lineage-specific marker of T-reg cells, was higher in CR cells when compared to their parental cell counterparts. Treatment with Epacadostat significantly suppressed FoxP3 expression which further support the relationship between metabolic reprogramming and immune evasion. Overall, we believe that our work will have potential impact on (i) how one can effectively exploits the KP pathway to treat CR tumors, and (ii) improved understanding on how CR cells evade immune surveillance. Supported by Department of Veterans Affairs, CDA2 award (1K2BX001289). Citation Format: Medhi Wangpaichitr, Chunjing Wu, Dan JM Nguyen, Ying-Ying Li, Lynn G. Feun, Niramol Savaraj. Targeting kynurenine pathway for the treatment of cisplatin-resistant lung cancer [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 5478.

Prognostic value of tumor infiltration immune cells in pancreatic cancer

Objective: To investigate the prognostic effect of tumour-infiltrating immune cell, including CD8(+) T cell, regulatory T-cell (Treg) and myeloid-derived suppressor cells (MDSC) on pancreatic patients. Methods: This study retrospectively collected the data of 80 patients who were histologically diagnosed of pancreatic cancer and underwent classical R0 surgical resection at Tianjin Medical University Cancer Institute and Hospital from January 2010 to May 2012. All patients survival were followed up until the cut-off date of January 2015. Clinicopathological features including immunohistochemical staining of FOXP3, CD8 and CD33 were reviewed as indice for evaluating the prognosis of pancreatic patients.The prognostic effect of tumour-infiltrating immune cells were analysed by Kaplan-Meier and Log-rank test. Multiple-factor analysis was conducted with the Cox regression model. The correlation between tumour-infiltrating immune cells and clinicopathological features was analysed by χ(2) test. The C57BL/6 mouse model was used to evaluate the efficacy of Treg and MDSC depletion therapy in vivo. Student's t-test was applied to assess the difference of the tumour volume, Ki-67 positive rate and CD8(+) T-cell infiltration proportion between depletion group and control group. Results: Eventually, 80 patients were included and no patient was lost during the follow-up period. The median follow-up time was 33.2 months (7.4-59.9 months). Patients with high level of tumour-infiltrating CD8(+) T cells had longer overall survival (OS) time ((21.6±11.9)months vs. (13.6±7.4)months, χ(2)=4.647, P = 0.031) than those with low level of tumour-infiltrating CD8(+) T cells. Tumor infiltration FOXP3(+) cells were strongly associated with reduced OS((20.9±8.5)months vs.(13.4±8.8)months, χ(2)=10.528, P=0.001), reduced relapse free survival (RFS) ((15.2±9.0)months vs. (9.5±8.8)months, χ(2)=6.288, P=0.012) and larger tumor size(χ(2)=4.073, r=0.226, P=0.044). The high intratumoural MDSC group showed a significantly shorter OS((23.5±11.8)months vs. (13.8±7.6)months, χ(2)=5.724, P=0.017), RFS((17.9±11.3)months vs. (10.2±7.5)months, χ(2)=7.430, P=0.006) and more advanced N stage (χ(2)=4.714, r=0.243, P=0.030) than the low intratumoural MDSC group. Multivariate Cox analysis revealed that pTNM (P=0.008), tumour-infiltrating Treg density (P=0.009) and intratumoural MDSC density (P=0.034) were independent and negative prognostic factors for OS; pTNM(P=0.003) and tumour-infiltrating MDSC level(P=0.018) were independent and negative factors for RFS. The experiment in vivo revealed that Treg and MDSC depletion therapy significantly decreased tumour volume in the C57BL/6 mouse model of subcutaneous tumours((1 396.3±442.5)mm(3) vs. (3 356.9±533.5)mm(3), t=4.986, P=0.018). Tumour Ki-67 positive rate significantly decreased (23%±5% vs. 55%±10%, t=3.130, P=0.011) in Treg and MDSC depletion group, whereas, the proportion of tumour-infiltrating CD8(+) T cells significantly increased in depletion groups (3.25%±0.69% vs. 0.76%±0.25%, t=3.393, P=0.007). Conclusions: Tumour-infiltrating Treg, MDSC level and pTNM stage are independent prognostic factors for patients with pancreatic cancer. Treg and MDSC depletion therapy can significantly retard tumour growth and increase the level of tumour-infiltrating CD8(+) T-cells in the C57BL/6 mouse model of subcutaneous tumours.

Melanoma-Derived Soluble DC-HIL/GPNMB Promotes Metastasis by ExcludingT-Lymphocytes from the Pre-Metastatic Niches.

Soluble factors from the primary tumor induce recruitment of bone marrow-derived progenitors to form tumor-supportive microenvironments or pre-metastatic niches in distal organs before metastasis. How tumor-secreted factors condition the sites for tumor progression remains ambiguous. B16 melanoma produces the secreted form of T cell-inhibitory DC-HIL (sDC-HIL) that travels to distal organs and potentiates the metastatic capacity of tumor cells. We studied the molecular mechanisms and found that sDC-HIL binds to select endothelial cells that co-localize with the sites where bone marrow-derived progenitors and tumor cells migrate. sDC-HIL-bound endothelial cells exist at a similar frequency in mice with or without tumors, and they are strongly associated with survival of intravenously injected tumor cells in the lung. sDC-HIL binding conferred T-cell suppressor function on the ECs and awakened the angiogenic property by inducing vascular endothelial growth factor expression, resulting in enhanced transendothelial migration of bone marrow-derived progenitors and tumor cells, but not for T cells. This selectivity is achieved by the T-cell binding of sDC-HIL, which prevents formation of the leading edges required for chemotaxis. Finally, inducing tumor expression of sDC-HIL significantly reduced tumor-infiltrated T cells. Therefore, the highly metastatic attribute of B16 melanoma can be explained by the endothelial gatekeeper function of sDC-HIL that limits lymphocyte transmigration to pre-metastatic niches.