Effective delivery of anti-PD-L1 siRNA with human heavy chain ferritin (HFn) in acute myeloid leukemia cell lines

Because of the high biocompatibility, self-assembly capability, and CD71-mediated endocytosis, using human heavy chain ferritin (HFn) as a nanocarrier would greatly increase therapeutic effectiveness and reduce possible adverse events. Anti-PD-L1 siRNA can downregulate the level of PD-L1 on tumor cells, resulting in the activation of effector T cells against leukemia. Therefore, this study aimed to produce the tumor-targeting siPD-L1/HFn nanocarrier. Briefly, the HFn coding sequence was cloned into a pET-28a, and the constructed expression plasmid was subsequently transformed into E. coli BL21. After induction of Isopropyl β-D-1-thiogalactopyranoside (IPTG), HFn was purified with Ni-affinity chromatography and dialyzed against PBS. The protein characteristics were analyzed using SDS-PAGE, Western Blot, and Dynamic light scattering (DLS). The final concentration was assessed using the Bicinchoninic acid (BCA) assay. The encapsulation was performed using the standard pH system. The treatment effects of siPD-L1/HFn were carried out on HL-60 and K-562 cancer cell lines. The RT-PCR was used to determine the mRNA expression of PD-L1. The biocompatibility and excretion of siPD-L1/HFn have also been evaluated. The expression and purity of HFn were well verified through SDS-PAGE, WB, and DLS. RT-PCR analyses also showed significant siRNA-mediated PD-L1 silencing in both HL-60 and K-562 cells. Our study suggested a promising approach for siRNA delivery. This efficient delivery system can pave the way for the co-delivery of siRNAs and multiple chemotherapies to address the emerging needs of cancer combination therapy.

Cross-talk between leukemic and immune cells at the tumor microenvironment in chronic lymphocytic leukemia: An update review

Chronic lymphocytic leukemia (CLL) is a mature-type B cell malignancy correlated with significant changes and defects in both the innate and adaptive arms of the immune system, together with a high dependency on the tumor microenvironment. Overall, the tumor microenvironment (TME) in CLL provides a supportive niche for leukemic cells to grow and survive, and interactions between CLL cells and the TME can contribute to disease progression and treatment resistance. Therefore, the increasing knowledge of the complicated interaction between immune cells and tumor cells, which is responsible for immune evasion and cancer progression, has provided an opportunity for the development of new therapeutic approaches. In this review, we outline tumor microenvironment-driven contributions to the licensing of immune escape mechanisms in CLL patients.

Comparison of the Diagnostic Performance of Antigen B Purified from Sheep Hydatid Cyst Fluid (HCF) with Commercial ELISA Kit

INTRODUCTION

Cystic echinococcosis (CE) is a zoonotic parasitic disease caused by the metacestode of Echinococcus granulosus. CE is a health problem in Middle Eastern countries, such as Iran. The purpose of this study was to purify subunit 8 KDa antigen B from crude sheep hydatid cyst fluid (HCF) and compare its sensitivity and specificity with a commercial human ELISA kit (PT-Hydatid-96).

METHODS

28 sera samples were collected from hydatid cyst patients who had surgery for a hydatid cyst and had their disease confirmed by pathology after the surgery. Furthermore, 35 samples of healthy individuals with no history of hydatid cysts were collected, as were nine serum samples from parasite-infected non-CE patients. HCF was obtained from sheep fertile cysts at a Sari slaughterhouse and used as an antigen. In an indirect ELISA test, the B antigen was employed, and the results were compared to those from a commercial ELISA kit.

RESULTS

The results of this study were analyzed using the Kappa test. The commercial ELISA kit showed 17 cases (23.6%) positive, 44 cases (61.1%) negative, and 11 cases (15.3%) borderline. B antigen showed that 18 (25%), 43 (59.7 %), and 11 (15.3%) were positive, negative, and borderline, respectively. One sample (1.4% of 72 total samples) of 35 serum samples from healthy individuals was positive using B antigen-based ELISA. In addition, all nine serum samples from parasite-infected non-CE patients were negative for both tests. The sensitivity and specificity of the commercial ELISA kit have been evaluated at 60.7% and 100%, respectively. For B antigenbased ELISA, these values are 64.3 and 97.7%, respectively.

CONCLUSION

Antigen B produced from hydatid cyst fluid is a promising option for serological identification of hydatid cysts in both infected and healthy individuals. In an indirect ELISA test, hydatid fluid antigen could be used as a precise source of detection.

Evaluation of mRNA Expressions of TOX and NR4As in CD8+ T cells in Acute Leukemia

Background

Thymocyte selection-associated high mobility group box protein (TOX) and members of the nuclear receptor 4A (NR4A) are known as transcription factors involved in T cell exhaustion.

Objective

To evaluate the mRNA expression of TOX and NR4A1-3 in CD8+ T cells in acute leukemia.

Methods

Blood samples were obtained from 21 ALL and 6 AML patients as well as 20 control subjects. CD8+ T cells were isolated using MACS. Relative gene expression of TOX and NR4A1-3 was then evaluated using qRT-PCR.

Results

Comparison of mRNA expression of TOX in CD8+ T cells showed no significant difference among the study groups (p>0.05), while the expression of NR4A1 was significantly lower in AML patients than in the control group (p=0.0006). Also, the expression of NR4A2 and NR4A3 was significantly lower in both ALL (p=0.0049 and p=0.0005, respectively) and AML (p=0.0019 and p=0.0055, respectively) patients.

Conclusion

NR4As expressions were found to be lower in CD8+ T cells from patients with AML and ALL compared to controls, whereas the mRNA expression of TOX showed no significant difference. Although TOX and NR4As are associated with CD8+ T cell exhaustion in solid tumors, they might play different roles in acute leukemia, which requires further investigation.

Combination therapy of acute myeloid leukemia by dual PI3K/mTOR inhibitor BEZ235 and TLR-7/8 agonist R848 in murine model

BACKGROUND

Due to the high relapse rate and toxicity of the common therapies in patients with acute myeloid leukemia (AML), modifications in the treatment strategies are required. The present study was conducted to determine the effects of combinational therapy with a dual PI3K/mTOR inhibitor, BEZ235, and TLR7/8 agonist, R848, on murine AML model.

METHODS

BEZ235 and R848 were administered to AML leukemic mice in either a single or combination treatment. Frequency of T-CD4+, T-CD8+, MDSCs, NK, exhausted T cells and the degranulation levels was measured via flow cytometry. The cytotoxicity and proliferation levels were evaluated by MTT assay. Then, the expression of iNOS, arginase-1, PD-L1, Gal-9, PVR, IFN-γ, TNF-α, IL-4, IL-10, IL-12 and IL-17 was investigated by Real-Time PCR. Organomegaly, body weight and survival rate were also monitored.

RESULTS

Following combinational therapy with BEZ235 and R848, increasing in the frequency of anti-tumor immune cells including T-CD4+ cells and M1 macroghages, and decreasing in pro-tumor immune cells including MDSCs, exhausted T-CD4+ and T-CD8+ cells and also M2 macrophages were observed. The functional defects of immune cells in term of proliferation, cytotoxicity, degranulation, and cytokines expression were improved in leukemic mice after treatment with BEZ235 and R848. Finally, organomegaly, body weight and survival analysis showed significant improvements after treatment with BEZ235 and R848.

CONCLUSION

Taken together, we indicated that the combinational therapy with BEZ235 and R848 could be considered as a potential and powerful therapeutic option for AML patients. Further clinical studies are required to expand our current findings.

Single domain antibodies specific for HER2 dimerization domain effectively disrupts HER2 dimerization

Dimer-dependent phosphorylation of HER2 receptor is a key event for the signal transduction of HER family of receptors which correlates with tumor invasion and metastasis. New generation of therapies based on dimerization domain inhibition using monoclonal or fragment antibodies was introduced. A potent method for manufacturing antibodies and antibody fragments is the phage display antibody library method. A recombinant phage was generated using the phage display method from synthetic dAb library. Subtractive biopanning was performed on sepharose 4b resin. Evaluation of success of subtractive biopanning was confirmed by the PCR fingerprinting after the fourth round of biopanning. The fourth round of biopanning results in the isolation of several dimerization domain reactive clones based on the polyclonal phage ELISA results. Monoclonal phage cell ELISA was used to select the positive clones with the highest affinity, and they were subsequently employed for functional tests. Cell-ELISA, MTT assay and dimerization inhibition test revealed that the reactivity and specificity of the selected monoclonal phage to dimerization domain of HER2. Further, Annexin V/PI staining and gene expression analysis showed that increased apoptosis rates. Also, in silico binding of the selected clones to conformational structure of HER2 was applied, using protein-protein docking tool of the ICM-Pro software, and showed sdAbs were specifically interacted with dimerization domain of the receptor. In conclusion, we have identified a single domain targeting HER2 dimerization, which represents a promising therapeutic and diagnostic candidate for HER2-positive cancers. Purified sdAb needs to more research to evaluate it both in vivo and in vitro via functional tests to determine if it can be applied for treatment and diagnostics.

Current Approaches of Immune Checkpoint Therapy in Chronic Lymphocytic Leukemia

OPINION STATEMENT

Increasing understanding of the complex interaction between leukemic and immune cells, which is responsible for tumor progression and immune evasion, has paved the way for the development of novel immunotherapy approaches in chronic lymphocytic leukemia (CLL). One of the well-known immune escape mechanisms of tumor cells is the up-regulation of immune checkpoint molecules. In recent years, targeting immune checkpoint receptors is the most clinically effective immunotherapeutic strategy for cancer treatment. In this regard, various immune checkpoint blockade (ICB) drugs are currently been investigating for their potential effects on improving anti-tumor immune response and clinical efficacy in the hematological malignancies; however, their effectiveness in patients with CLL has shown less remarkable success, and ongoing research is focused on identifying strategies to enhance the efficacy of ICB in CLL.

Evaluation of mRNA Expression of CD244 and Its Adapter Molecules in CD8+ T Cells in Acute Leukemia

Background

This study investigated the role of the immune-checkpoint receptor (ICR), CD244, and its adapter molecules, in CD8+ T cells in acute leukemia.

Methods

Blood samples were obtained from 21 acute lymphoblastic leukemia (ALL) and 6 acute myeloid leukemia (AML) patients and 20 control subjects. Relative gene expression of CD244, immune receptor tyrosine-based switch motif-associated protein (SA), EWS/FLI1-activated transcript 2 (EAT-2), and LncRNA-GSTT1-AS1 were evaluated using quantitative reverse transcription polymerase chain reaction.

Results

Expression of CD244, SAP, and EAT-2 were significantly lower in CD8+ T cells from ALL patients than those from control subjects. Interestingly, the expression of SAP was much lower than that of CD244, indicating a lower ratio of SAP to CD244. Also, SAP expression was significantly lower in AML patients compared to the control group. Expression of LncRNA-GSTT1-AS1 showed no significant difference in ALL and AML patients compared to control subjects.

Conclusion

The low SAP/CD244 expression ratio in CD8+ T cells in ALL suggests an inhibitory role for CD244 in ALL.

In Silico Vaccine Design and Expression of the Multi-Component Protein Candidate against the Toxoplasma gondii Parasite from MIC13, GRA1, and SAG1 Antigens

Background

We aimed to design a B and T cell recombinant protein vaccine of Toxoplasma gondii with in silico approach. MIC13 plays an important role in spreading the parasite in the host body. GRA1 causes the persistence of the parasite in the parasitophorous vacuole. SAG1 plays a role in host-cell adhesion and cell invasion.

Methods

Amino acid positions 73-272 from MIC13, 71-190 from GRA1, and 101-300 from SAG1 were selected and joined with linker A(EAAAK)A. The structures, antigenicity, allergenicity, physicochemical properties, as well as codon optimization and mRNA structure of this recombinant protein called MGS1, were predicted using bioinformatics servers. The designed structure was synthesized and then cloned in pET28a (+) plasmid and transformed into Escherichia coli BL21.

Results

The number of amino acids in this antigen was 555, and its antigenicity was estimated to be 0.6340. SDS-PAGE and Western blotting confirmed gene expression and successful production of the protein with a molecular weight of 59.56kDa. This protein will be used in our future studies as an anti-Toxoplasma vaccine candidate in animal models.

Conclusion

In silico methods are efficient for understanding information about proteins, selecting immunogenic epitopes, and finally producing recombinant proteins, as well as reducing the time and cost of vaccine design.

Evaluation of mRNA Expression of CD244 and Its Adapter Molecules in CD8+ T Cells in Acute Leukemia

Background

This study investigated the role of the immune-checkpoint receptor (ICR), CD244, and its adapter molecules, in CD8+ T cells in acute leukemia.

Methods

Blood samples were obtained from 21 acute lymphoblastic leukemia (ALL) and 6 acute myeloid leukemia (AML) patients and 20 control subjects. Relative gene expression of CD244, immune receptor tyrosine-based switch motif-associated protein (SA), EWS/FLI1-activated transcript 2 (EAT-2), and LncRNA-GSTT1-AS1 were evaluated using quantitative reverse transcription polymerase chain reaction.

Results

Expression of CD244, SAP, and EAT-2 were significantly lower in CD8+ T cells from ALL patients than those from control subjects. Interestingly, the expression of SAP was much lower than that of CD244, indicating a lower ratio of SAP to CD244. Also, SAP expression was significantly lower in AML patients compared to the control group. Expression of LncRNA-GSTT1-AS1 showed no significant difference in ALL and AML patients compared to control subjects.

Conclusion

The low SAP/CD244 expression ratio in CD8+ T cells in ALL suggests an inhibitory role for CD244 in ALL.

Investigation of Expression Profile of Placenta-specific 1 (PLAC1) in Acute Myeloid and Lymphoid Leukemias

Background

Placenta-specific 1 (PLAC1) is one of the cancer-testis-placenta antigens that has no expression in normal tissue except placenta trophoblast and testicular germ cells, but is overexpressed in a variety of solid tumors. There is a lack of studies on the expression of PLAC1 in leukemia. We investigated expression of PLAC1 in Acute Myeloid Leukemia (AML) and Acute Lymphoblastic Leukemia (ALL).

Methods

In this study, we investigated expression pattern of PLAC1 gene in peripheral blood and bone marrow mononuclear cells of newly-diagnosed patients with AML (n=31) and ALL (n=31) using quantitative real-time PCR. Normal subjects (n=17) were considered as control. The PLAC1 protein expression in the samples were also detected using western blotting.

Results

Our data demonstrated that PLAC1 transcripts had 2.7 and 2.9 fold-change increase in AML and ALL, respectively, compared to normal samples. PLAC1 transcript expression was totally negative in all studied normal subjects. Level of PLAC1 mRNA expression in ALL statistically increased compared to normal samples (p=0.038). However, relative mRNA expression of PLAC1 in AML was not significant in comparison to normal subjects (p=0.848). Furthermore, relative mRNA expression of PLAC1 in AML subtypes was not statistically significant (p=0.756). PLAC1 gene expression showed no difference in demographical clinical and para-clinical parameters. Western blotting confirmed expression of PLAC1 in the ALL and AML samples.

Conclusion

Considering PLAC1 expression profile in acute leukemia, PLAC1 could be a potential marker in leukemia which needs complementary studies in the future.

Evaluation of the anti-tumor effects of an anti-Human Epidermal growth factor receptor 2 (HER2) monoclonal antibody in combination with CD11b+/Gr-1+ myeloid cells depletion using a recombinant peptibody in 4 T1-HER2 tumor model

INTRODUCTION

Clinical efficacy of Human Epidermal growth factor Receptor 2 (HER2) targeted strategies is limited due to impaired anti-tumor responses negatively regulated by immunosuppressive cells. We thus, investigated the inhibitory effects of an anti-HER2 monoclonal antibody (1 T0 mAb) in combination with CD11b⁺/Gr-1⁺ myeloid cells depletion in 4 T1-HER2 tumor model.

METHODS

BALB/c mice were challenged with human HER2-expressing 4 T1 murine breast cancer cell line. A week post tumor challenge, each mouse received 50 µg of a myeloid cells specific peptibody every other day, or 10 mg/kg of 1 T0 mAb two times a week, and their combination for two weeks. The treatments effect on tumor growth was measured by calculating tumor size. Also, the frequencies of CD11b⁺/Gr-1⁺ cells and T lymphocytes were measured by flow cytometry.

RESULTS

Peptibody treated mice indicated tumor regression and 40 % of the mice eradicated their primary tumors. The peptibody was capable to deplete notably splenic CD11b⁺/Gr-1⁺ cells as well as intratumoral CD11b⁺/Gr-1⁺ cells (P < 0.0001) and led to an increased number of tumor infiltrating CD8⁺ T cells (3.3 folds) and also that of resident tumor draining lymph nodes (TDLNs) (3 folds). Combination of peptibody and 1 T0 mAb resulted in enhanced expansion of tumor infiltrating CD4 + and CD8⁺ T cells which was associated with tumor eradication in 60 % of the mice.

CONCLUSIONS

Peptibody is able to deplete CD11b⁺/Gr-1⁺ cells and increase anti-tumoral effects of the 1 T0 mAb in tumor eradication. Thus, this myeloid population have critical roles in development of tumors and their depletion is associated with induction of anti-tumoral responses.

Relative Expression of BATF and CD112 in PBMC of Patients with Chronic Lymphocytic Leukemia

OBJECTIVE

BATF, as a transcription factor, and CD112, as a receptor for TIGIT, are involved in T-cell exhaustion. We investigated BATF and CD112 gene expression in the peripheral blood mononuclear cells from CLL patients and healthy subjects.

METHODS

In a case-control study, 33 patients with CLL and 20 sex- and age-matched healthy individual were enrolled. Diagnosis and classification of patients was done according to immunophenotyping via flow cytometry and RAI staging system, respectively. Relative mRNA expression of BATF and CD112 was measured using qRT-PCR.

RESULT

Our results showed that the expression of BATF and CD112 in CLL samples were significantly decreased in comparison those of the healthy controls (P = 0.0236 and P = 0.0002, respectively).

CONCLUSION

These findings suggest the role of BATF and CD112 not only as a role in T cell exhaustion, but in effector differentiation program in CLL, which warrants further studies in future.

Glucose Metabolism in Acute Myeloid Leukemia Cell Line Is Regulated via Combinational PI3K/AKT/mTOR Pathway Inhibitors

Background

Metabolism reprogramming is a survival mechanism in acute myeloid leukemia (AML) cells in the tumor microenvironment. Therefore, we investigated the effect of signaling pathway inhibitors on the expression of genes rewired in the metabolic pathway of AML cells.

Methods

HL-60 cells were treated with Idelalisib, MK-2206, and Everolimus, which respectively are selective inhibitors of phosphatidylinositol-3-kinase (PI3K), AKT, and the mammalian target of rapamycin (mTOR), either individually or in combination. The relative expressions of glucose transporter 1, hexokinase 2, pyruvate kinase, pyruvate dehydrogenase E1, citrate synthase, isocitrate dehydrogenase 2, and hypoxia inducible factor 1 subunit alpha were determined by real-time PCR.

Results

The combined treatment of HL-60 cells with Idelalisib, MK-2206, and Everolimus decreased the expression of glucose transporter 1, hexokinase 2, pyruvate kinase M2, pyruvate dehydrogenase E1, citrate synthase, isocitrate dehydrogenase 2, and hypoxia inducible factor 1 subunit alpha.

Conclusions

A combination of PI3K/AKT/mTOR pathway inhibitors regulates the expression of genes involved in glycolysis, pyruvate dehydrogenase complex (PDH), and the tricarboxylic acid (TCA) cycle and interferes with metabolic reprogramming and immune evasion mechanisms of AML leukemic cells. Combinational therapy approaches to block these pathways might be a promising and novel therapeutic strategy for targeting the metabolic requirements of AML cells.

Expression of Galectin-9-related immune checkpoint receptors in B-cell acute lymphoblastic leukemia

Objectives

Exhausted CD8+ T-cells over-express immune checkpoint receptors (ICRs), which interact with their ligands on malignant cells. However, some ICRs have been reported to be expressed on both T-cells and tumor cells, including V-domain immunoglobulin suppressor of T cell activation (VISTA), Galectin-9, and T-cell immunoglobulin mucin-3 (TIM-3). We aimed to evaluate the mRNA expression of VISTA, Galectin-9, and TIM-3 on CD8+ T-cells and leukemic cells in B-cell acute lymphoblastic leukemia (B-ALL).

Materials and Methods

Samples were obtained from 26 untreated B-ALL patients and 25 control subjects. CD8+ T-cells were isolated using Magnetic Activated Cell Sorting (MACS). Relative gene expression was then evaluated by qRT-PCR with specific primers for VISTA, Galectin-9, and TIM-3. Also, the mRNA expression profile and clinical data of 154 B-ALL patients were obtained from the TARGET.

Results

mRNA expression of Galectin-9 on CD8+ T-cells in B-ALL patients was significantly lower than those in the control group (P=0.043), while VISTA expression was not significantly different between the two study groups (P=0.259). Besides, TIM-3 expression was significantly higher in B-ALL patients than in the control group (P<0.001). Also, data obtained from TARGET showed that the relapse incidence was not significantly different between patients with high and low expression of Galectin-9 and TIM-3 in leukemic cells (P=0.360 and P=0.655, respectively).

Conclusion

Collectively, gene expression results suggest an important role for TIM-3, but not VISTA and Galectin-9, in B-ALL and it seems that TIM-3 could be a candidate for immune checkpoint therapy.

Detection of Novel Autoantibodies to Nucleolin's RNA-binding Domains as a Serum Tumor Biomarker Through ELISA

Expression and location of nucleolin are often abnormal in malignancies, which may result in the production of autoantibodies. Despite this, the identification of such autoantibodies may be essential for the early diagnosis and prognosis of cancers. In this investigation, the recombinant nucleolin protein was generated using an Escherichia coli expression system and was used an indirect enzyme-linked immunosorbent assay to detect anti-nucleolin autoantibodies in cancer patients' sera. Lung cancer patients' autoantibodies displayed the highest seroreactivity with the recombinant protein, with area under the curve of 0.948 and sensitivity and specificity of 85% and 96.67%, respectively (accuracy=92%). Anti-nucleolin autoantibodies were linked with lung tumor size (r=0.793), tumor, node, metastasis staging (r=0.643), and proliferation (r=0.744). These autoantibodies distinguished patients with early-stage lung cancer from healthy controls. Since anti-nucleolin autoantibodies are strongly linked to tumor size, clinical staging, and growth, they can be used to measure how well a treatment is working.

Evaluation of Innate Lymphoid Cells (ILCs) Population in the Mouse Model of Colorectal Cancer

BACKGROUND

Innate Lymphoid Cells (ILCs) promote tissue homeostasis, contribute to the immune defense mechanisms, and play important roles in the initiation of immune responses and chronic inflammation.

OBJECTIVE

To understand the roles of innate lymphoid cells in the pathophysiology of colorectal cancer (CRC) in the mouse model.

METHODS

CRC was induced using azoxymethane (AOM) and dextran sulfate sodium (DSS) in Balb/c mice (the chemically induced group=18 mice), or orthotopic injection of CT-26 cell line into the colon of another set of Balb/c mice (the orthotopic group=14mice). Normal saline was injected into 18 mice, as the sham group. After 80 days, the chemically induced group was divided into two subgroups, dysplasia (8 mice) and reparative change (10 mice), based on pathological examinations. The frequencies of ILC1, 2, and 3 were then measured in colon tissues using flow cytometry by four markers including an anti-mouse lineage cocktail (FITC anti-mCD3/FITC anti-mGr-1/FITC anti-mCD11b/ FITC anti-mCD45R (B220)/FITC anti-mTer-119), PE/Cy7 anti-mouse CD45, PE anti-mouse CD117 (c-kit), and APC anti-mouse IL-33 Rα (ST2).

RESULTS

The total ILC population was significantly higher in the chemically induced reparative change compared with the sham group. ILC1 percentage in the chemically induced reparative change was significantly higher compared to those in the other three groups (Sham, chemically induced dysplasia and orthotopic dysplasia). The orthotopic dysplasia group showed more ILC3 percentage than the other groups.

CONCLUSION

ILC1 and ILC3 subgroups increased significantly in reparative and dysplastic experimental CRC respectively. Thus ILC1 may have an inhibitory effect on tumor growth whereas ILC3 promotes tumor progression.

PD-1 AND TIM-3 BLOCKING CANNOT ENHANCE APOPTOSIS OF CHRONIC LYMPHOCYTIC LEUKEMIA CELLS INDUCED BY PERIPHERAL BLOOD CD8+ T CELLS

AIM

Given the invaluable success of immune checkpoint inhibitors for tumor immunotherapy, in this study, the effect of programmed cell death 1 (PD-1) and T cell immunoglobulin-3 (TIM-3) blocking was investigated to induce apoptosis of leukemic cells by exhausted CD8⁺ T cells in patients with chronic lymphocytic leukemia (CLL).

MATERIALS AND METHODS

Peripheral blood CD8⁺ T cells were positively isolated from 16 CLL patients using magnetic beads separation method. Isolated CD8⁺ T cells were treated with either blocking anti-PD-1, anti-TIM-3 and isotype-matched control antibodies and then co-cultured with CLL leukemic cells as target. The percentage of apoptotic leukemic cells and the expression of apoptosis-related genes were evaluated by flow cytometry and real-time polymerase chain reaction methods, respectively. Interferon gamma and tumor necrosis factor alpha concentration was also measured by ELISA.

RESULTS

Flow cytometric analysis of apoptotic leukemic cells indicated that the blockade of PD-1 and TIM-3 did not significantly enhance the apoptosis of CLL cells by CD8+ T cells, which then were confirmed by analysis of BAX, BCL2 and CASP3 gene expression, which was similar in blocked and control groups. No significant difference was found between blocked and control groups in terms of interferon gamma and tumor necrosis factor alpha production by CD8+ T cells.

CONCLUSION

We concluded that the blockade of PD-1 and TIM-3 is not an effective strategy to restore the function of CD8+ T cells in CLL patients at the early clinical stages of the disease. Further in vitro and in vivo studies are needed to more address the application of immune checkpoint blockade in CLL patients.

Enhancement of immune responses by vaccine potential of three antigens, including ROP18, MIC4, and SAG1 against acute toxoplasmosis in mice

Toxoplasma gondii (T. gondii) causes considerable financial losses in the livestock industry and can present serious threats to pregnant women, as well as immunocompromised patients. Therefore, it is required to design and produce an efficient vaccine for controlling toxoplasmosis. The present study aimed to evaluate the protective immunity induced by RMS protein (ROP18, MIC4, and SAG1) with Freund adjuvant, calcium phosphate nanoparticles (CaPNs), and chitosan nanoparticles (CNs) in BALB/c mice. The RMS protein was expressed in Escherichia coli (E. coli) and purified using a HisTrap HP column. Thereafter, cellular and humoral immunity was assessed by injecting RMS protein on days 0, 21, and 35 into four groups [RMS, RMS-chitosan nanoparticles (RMS-CNs), RMS-calcium phosphate nanoparticles (RMS-CaPNs), and RMS-Freund]. Phosphate buffered saline (PBS), CNs, CaPNs, and Freund served as the four control groups. The results displayed that vaccination with RMS protein and adjuvants significantly elicited the levels of specific IgG antibodies and cytokines against toxoplasmosis. There were high levels of total IgG, IgG2a, and IFN-γ in vaccinated mice, compared to those in the control groups, especially in the RMS-Freund, indicating a Th-1 type response. The vaccinated and control mice were challenged intraperitoneally with 1 × 10³ tachyzoites of the T. gondii RH strain four weeks after the last injection, and in RMS-Freund and RMS-CaPNs groups, the highest increase in survival time was observed (15 days). The RMS can significantly increase Th1 and Th2 responses; moreover, multi-epitope vaccines with adjuvants can be a promising strategy for the production of a vaccine against toxoplasmosis.

Cloning, expression and characterization of a peptibody to deplete myeloid derived suppressor cells in a murine mammary carcinoma model

BACKGROUND

Myeloid derived suppressor cells (MDSCs) are an immature heterogeneous population of myeloid lineage that attenuate the anti-tumor immune responses. Depletion of MDSCs has been shown to improve efficacy of cancer immunotherapeutic approaches. Here, we expressed and characterized a peptibody which had previously been defined by phage display technique capable of recognizing and depleting murine MDSCs.

MATERIALS AND METHODS

Using splicing by overlap extension (SOE) PCR, the coding sequence of the MDSC binding peptide and linker were synthesized and then ligated into a home-made expression plasmid containing mouse IgG2a Fc. The peptibody construct was transfected into CHO-K1 cells by lipofectamine 3000 reagent and the resulting fusion protein was purified with protein G column and subsequently characterized by ELISA, SDS-PAGE and immunoblotting. The binding profile of the peptibody to splenic MDSCs and its MDSC depletion ability were then tested by flow cytometry.

RESULTS

The purified peptibody appeared as a 70 KDa band in Western blot. It could bind to 98.8% of splenic CD11b⁺/Gr-1⁺ MDSCs. In addition, the intratumoral MDSCs were significantly depleted after peptibody treatment compared to their PBS-treated negative control counterparts (P < 0.05).

CONCLUSION

In this study, a peptibody capable of depleting intratumoral MDSCs, was successfully expressed and purified. Our results imply that it could be considered as a potential tool for research on cancer immunotherapy.

Combined Blockade Of PD-1 and TIGIT is not Sufficient to Improve the Function Of CD8+ T-Cells in Chronic Lymphocytic Leukemia

BACKGROUND AND OBJECTIVE

Blockade of immune checkpoint receptors in the treatment of cancers has been mentioned in several studies. Here, we investigated the efficacy of combined blockade of two inhibitory receptors, PD-1 and TIGIT, in restoring functional features of CD8+ T-cells in CLL.

METHODS

CD8+ T-cells were separated from the peripheral blood of 11 CLL patients and targeted with malignant B-cells isolated from the same patients. Cells were then stimulated with anti-CD3/CD28 and PMA/ionomycin to assess their proliferative response and cytotoxic activity using MTT and CD107a degranulation assays, respectively. Cytokine production of isolated CD8+ T-cells was also determined using ELISA.

RESULTS

There were no significant differences in proliferation and cytotoxic activity of CD8+ T-cells co-blocked with anti-PD-1/TIGIT compared to those single blocked with anti-PD-1, anti-TIGIT, or the control antibody. There was no significant difference in cytokine production of mentioned groups, either.

CONCLUSIONS

Collectively, combined blockade of PD-1 and TIGIT failed to restore the proliferation and function of CD8+ T-cells isolated from CLL patients.

Expression Modulation of Immune Checkpoint Molecules by Ibrutinib and Everolimus Through STAT3 in MCF-7 Breast Cancer Cells

Tumor-targeted therapy with small-molecule inhibitors (SMIs) has been demonstrated to be a highly effective therapeutic strategy for various cancers. However, their possible associations with immune evasion mechanisms remain unknown. This study examined the association of inhibitors of the protein kinase B (AKT), mammalian target of rapamycin (mTOR), and Bruton’s tyrosine kinase (BTK) signaling pathways with the expression of immune checkpoint ligands programmed death-ligand 1 (PD-L1), CD155, and galectin-9 (Gal-9) in a breast cancer cell line. MCF-7 cells were treated with everolimus, MK-2206, and ibrutinib. An MTT assay was used to determine the optimal dose for all drugs. A real-time polymerase chain reaction was utilized to measure the mRNA expression of PD-L1, CD155, and Gal-9. The western blot technique was also employed to evaluate the protein expression of the phosphorylated signal transducer and activator of transcription 3 (STAT3). The optimal doses of everolimus, MK-2206, and ibrutinib were observed to be 200, 320, and 2000 nM, respectively. The PD-L1 and CD155 mRNA expression was significantly decreased following the treatment with everolimus and ibrutinib, but not with MK-2206. There were no differences in Gal-9 expression between the single-treated and control groups; however, combined treatment with everolimus and ibrutinib increased its mRNA expression. Everolimus and ibrutinib both inhibited constitutive STAT3 phosphorylation in MCF-7, which was more pronounced in combination treatment. The findings regarding the modulation of PD-L1, CD155, and Gal-9 molecules by SMIs emphasize the crosstalk between the expression of these immune checkpoint molecules and AKT/mTOR/BTK signaling pathways through STAT3 as a critical transcription factor.

The Effects of PI3K/Akt/mTOR Signaling Pathway Inhibitors on the Expression of Immune Checkpoint Ligands in Acute Myeloid Leukemia Cell Line

Up-regulation of immune checkpoint ligands is considered as one of the most important immune escape mechanisms in acute myeloid leukemia (AML). Herein, we investigate a relationship between the inhibition of PI3K/Akt/mTOR signaling pathways and the regulation of immune checkpoint ligands in AML cells. The HL-60 cell line was treated with idelalisib as PI3K inhibitor, MK-2206 as Akt inhibitor, and everolimus as mTOR inhibitor either in a single or combined format. Cell viability and apoptosis were evaluated using MTT and flow cytometry assays, respectively. The relative expression of PD-L1, galectin-9, and CD155 was determined by real-time PCR. Our findings demonstrated decreased proliferation and increased apoptosis of HL-60 cells after treatment with idelalisib, MK-2206, and everolimus. As expected, the combined treatment showed a more inhibiting effect than the single treatment. Interestingly, our results elucidated that the expression of PD-L1 and Gal-9 but not MK-2206 decreased after treatment with idelalisib and everolimus. Regarding CD155, the expression of this molecule was downregulated after treatment with everolimus, but not idelalisib and MK-2206. However, combined treatment of HL-60 cells with two or three inhibitors decreased the expression levels of PD-L1, Gal-9, and CD155 checkpoint ligands. We showed that PI3K/Akt/mTOR pathway inhibitors not only serve as cytotoxic drugs but also regulate the expression of immune checkpoint ligands and interfere with the immune evasion mechanisms of AML leukemic cells. Combinational treatment approaches to block these pathways might be a promising and novel therapeutic strategy for AML patients via interfering in immune escape mechanisms.

Tim-3 and PD-1 blocking cannot restore the functional properties of natural killer cells in early clinical stages of chronic lymphocytic leukemia: An in vitro study

Background

Programmed death-1 (PD-1) and T-cell immunoglobulin- and mucin-domain-containing molecule-3 (Tim-3) are two major immune checkpoint receptors expressed on immune cells and their expression is related to the exhaustion phenotype. In the present in vitro study, blocking of PD-1 and Tim-3 molecules was performed on isolated natural killer (NK) cells from patients with chronic lymphocytic leukemia (CLL) to restore their functional properties.

Materials and Methods

NK cells fraction was positively isolated from fresh peripheral blood of 18 CLL patients, treated with anti-PD-1 and anti-Tim-3 blocking monoclonal antibodies and co-cultured with K562 target cells to evaluate their apoptosis induction by Annexin V-PI method. Blocked NK cells were also incubated with anti-CD107a antibody to assess their degranulation properties by flow cytometry. The level of secreted tumor node factor-alpha (TNF-α) and interferon-gamma (IFN-γ) by NK cells was also measured by ELISA.

Results

Our results showed similar functional properties in terms of degranulation and apoptosis of K562 target cells by isolated NK cells from CLL patients in PD-1/Tim-3 blocked and control groups. It was also shown that blocking of PD-1 and Tim-3 could not improve the production of pro-inflammatory TNF-α and IFN-γ cytokines by isolated NK cells from CLL patients.

Conclusion

Altogether, our results indicated that pretreatment of NK cells with anti-PD-1 and anti-Tim-3 blocking antibodies in CLL patients at early clinical stages cannot improve their functional properties. Besides many other malignancies, the application of checkpoint inhibitors in CLL needs more investigations and complementary studies.

Treatment by PI3K/mTOR Inhibitor BEZ235 Combined with TLR-7/8 Agonist Interfere with Immune Evasion Mechanisms of WEHI-3 Mouse Leukemia Cells

BACKGROUND

Several PI3K/Akt/mTOR pathway inhibitors and TLR agonists induce tumor cell death. However, the mechanisms of these therapeutic approaches in acute myeloid leukemia (AML) cells are still unknown.

OBJECTIVES

To investigate the effects of BEZ235, as a dual inhibitor of PI3K and mTOR pathways, and TLR7/8 agonist R848 on the expression and regulation of the immune inhibitory molecules in myeloid leukemia cells.

METHODS

WEHI-3 leukemia cells were incubated with dual PI3K and mTOR inhibitor BEZ235 and TLR7/8 agonist R848 for 48 hrs. Firstly, cell viability was assessed by MTT method. The semi-quantitative relative mRNA expression of Galectin-9 (Gal-9), PD-L1, PVR, and STAT3 was assessed according to HPRT as a housekeeping gene. Finally, the protein expression of phosphorylated STAT3 was evaluated by western blotting analysis.

RESULTS

WEHI-3 cells showed growth inhibition following treatment with BEZ235 and R848 whose combination exerted more proliferation arrest. The mRNA expression of Gal-9, PD-L1 and PVR immune checkpoint molecules significantly reduced in treated cells with BEZ235 and R848. Combined treatment indicated more reduction compared with the single treatment. Finally, the expression and phosphorylation of STAT3 were down-regulated after a single or dual treatment with BEZ235 and R848.

CONCLUSION

Our results conclude that treatment with the combination of BEZ235 and R848 interferes with immune evasion mechanisms through STAT3-signaling pathway in WEHI-3 leukemia cells.

CD8+ T-cells Co-expressing PD-1 and TIGIT Are Highly Frequent in Chronic Lymphocytic Leukemia

The role of immune checkpoint receptors in T-cell exhaustion has been demonstrated in several cancers. We investigated the co-expression of TIGIT/PD-1 and LAG-3/PD-1 cells in patients with chronic lymphocytic leukemia (CLL). The frequencies of TIGIT+PD-1+CD8+and LAG-3+PD-1+CD8+cells and relative mRNA expression of LSECtin and CD155 were examined in PBMCs from 33 CLL patients and 20 controls. The percentage of TIGIT+PD-1+CD8+cells was significantly higher in CLL patients than in control subjects, with the preference in advanced stage patients. However, LAG-3+PD-1+CD8+cell percentage was significantly lower in CLL patients than in the control subjects and no significant difference were found between the early and advanced stages of the disease. An increase in the mRNA expression level of LSECtin, but not that of CD155, was observed in CLL patients compared to the control subjects. Collectively, a higher co-expression of PD-1 and TIGIT on CD8+ T-cells in CLL compared to control subjects suggests an important role of TIGIT in T-cell exhaustion in CLL patients especially those with advanced disease.

Blockade of PD-1 and TIM-3 immune checkpoints fails to restore the function of exhausted CD8+ T cells in early clinical stages of chronic lymphocytic leukemia

Blocking antibodies targeting immune checkpoint molecules achieved invaluable success in tumor therapy and amazing clinical responses in a variety of cancers. Although common treatment protocols have improved overall survival in patients with chronic lymphocytic leukemia (CLL), they continue to relapse and progress. In the present in vitro study, the application of anti-PD-1 and anti-TIM-3 blocking antibodies was studied to restore the function of exhausted CD8⁺ T cells in CLL. CD8⁺ T cells were isolated from peripheral blood of 20 patients with CLL, treated with blocking antibodies, and cocultured with mitomycin-frozen non-CD8⁺ T cell fraction as target cells. Cultures were stimulated with anti-CD3/CD28 antibodies to assess the proliferation of CD8⁺ T cells by MTT and stimulated with PMA/ionomycin to measure the levels of CD107a expression and cytokine production by flow cytometry and ELISA, respectively. Our results showed that the blockade of PD-1 and TIM-3 does not improve the proliferation of CD8⁺ T cells in CLL patients. No significant difference was found between control and blocked groups in terms of degranulation properties and production of IFN-γ, TNF-α, IL-2, and IL-10 by CD8⁺ T cells. We observed that pre-treatment of CD8⁺ T cells with blocking antibodies in CLL patients at early clinical stages had no effects on restoring their functional properties. Further in vitro and in vivo complementary studies are required to more explore the utility of checkpoint inhibitors for CLL patients.

Cytokine profiling in Iranian patients with COVID-19; association with clinical severity

BACKGROUND

SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19), is recognized for the first time in Wuhan, China. The cytokine storm is a known factor causing major clinical symptoms leading to death in COVID-19 patients.

OBJECTIVE

To investigate and compare the serum levels of different cytokines in COVID-19 patients with different clinical severity.

METHODS

Concentrations of serum cytokines, including IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, TNF-α, IFN-γ, and GM-CSF, were measured in 61 COVID-19 patients and 31 normal controls with ELISA. We investigated the correlation between the levels of these cytokines and clinical severity, CRP level, neutrophil and lymphocyte count in patients with COVID-19.

RESULTS

Our data indicated that the levels of IL-1β, IL-2, IL-4, IL-6, IL-8, TNF-α, IFN-γ, and GM-CSF, but not IL-10 were significantly increased in COVID-19 patients compared to normal controls. Statistical analysis showed that the level of IL-1β, IL-2, IL-4, IL-6, IL-8, TNF-α, IFN-γ, and GM-CSF were higher in severe COVID-19 than those of mild cases. The concentrations of all mentioned cytokines were negatively associated with the absolute count of lymphocytes, and positively correlated with the CRP level and the absolute count of neutrophils.

CONCLUSION

The current study suggests that high levels of various cytokines correlate with the disease severity and immunopathogenesis of COVID-19.

Protective efficacy by a novel multi-epitope vaccine, including MIC3, ROP8, and SAG1, against acute Toxoplasma gondii infection in BALB/c mice

Toxoplasma gondii is an intracellular apicomplexan parasite, which can cause a serious infectious disease in pregnant women and immunocompromised individuals. Therefore, the development of a polyvalent vaccine consisting of all stages of the parasite life cycle using the epitopes from tachyzoites, bradyzoites, and sporozoites is likely to be required for complete protective immunity. In this study, we designed protein vaccine candidate based on the prediction of specific epitopes (i.e., B cell and T cell) from three Toxoplasma gondii antigens. The MRS protein (MIC3: 30-180, ROP8: 85-185, and SAG1: 85-235) was expressed in Escherichia coli, and purification was performed using a HisTrap HP column and then we evaluated immunogenicity and protective property in BALB/c mice. Seventy-two mice were randomly divided into six groups, including three vaccinations (i.e., MRS, MRS-Freund, and MRS-Calcium Phosphate Nanoparticles (MRS-CaPNs)) and three control (i.e., Phosphate-buffered saline, Freund, and CaPNs) groups. All groups were immunized three times via subcutaneous injection within three-week intervals. In the vaccination groups, the BALB/c mice were injected with 20 μg of MRS protein for the first time and 10 μg of MRS for the next two times. Antibodies, cytokines, and splenocytes proliferation in the immunized mice were assayed using the enzyme-linked immunosorbent assay. Protective efficacy was analyzed by challenging the immunized mice with T. gondii of RH strain. Antibody, cytokine, and lymphocyte proliferation assays showed that the mice immunized with MRS induced stronger humoral and T helper type 1 cell-mediated immune responses, compared to the control mice. However, co-immunization with adjuvants (i.e., Freund and CaNPs) resulted in impaired immune responses. Effective protection against the parasite achieved an increase in survival time in the immunized mice, especially in the MRS-CaNPs group. The obtained results of the present study demonstrated that multi-epitope protein vaccination, MRS, is a potential strategy against toxoplasmosis infection. In addition, the vaccine co-delivered with CaPNs could provide an important key for vaccine candidate to control T. gondii infection.

The Radiosensitizing Effect of Olanzapine as an Antipsychotic Medication in Glioblastoma Cell

BACKGROUND

Radiotherapy is used as one of the most effective regimens for cancer treatment, while radioresistance is a major drawback in cancer treatment.

OBJECTIVES

The aim of this study was to evaluate the sensitizing effect of olanzapine (OLA) with X-ray on glioblastoma (U-87 MG) cells death.

METHODS

The synergistic killing effect of OLA with ionizing radiation (IR) on glioma was evaluated by colony formation assay. The generations of reactive oxygen species (ROS) and protein carbonyl (PC) as oxidized protein were determined in OLA and irradiated cells.

RESULTS

The results of this study showed that OLA reduced the number of colonies in irradiated glioma cells. OLA elevated ROS and PC levels in irradiated cells. The synergistic killing effect of OLA with IR in U-87 MG cell was observed at concentrations 1 µM and 20 µM of OLA. The maximum radiosensitizing effect of OLA was observed at concentration of 20 µM.

CONCLUSION

The present study demonstrates that OLA has radiosensitizing effect on cell death induced by IR in glioma cells.

Immune evasion mechanisms in acute myeloid leukemia: A focus on immune checkpoint pathways

Immune surveillance mechanisms comprising of adaptive and innate immune systems are naturally designed to eliminate AML development. However, leukemic cells apply various immune evasion mechanisms to deviate host immune responses resulting tumor progression. One of the recently well-known immune escape mechanisms is over-expression of immune checkpoint receptors and their ligands. Introduction of blocking antibodies targeting co-inhibitory molecules achieved invaluable success in tumor targeted therapy. Moreover, several new co-inhibitory pathways are currently studying for their potential impacts on improving anti-tumor immune responses. Although immunotherapeutic strategies based on the blockade of immune checkpoint molecules have shown promising results in a number of hematological malignances, their effectiveness in AML patients showed less remarkable success. This review discusses current knowledge about the involvement of co-inhibitory signaling pathways in immune evasion mechanisms of AML and potential application of immune checkpoint inhibitors for targeted immunotherapy of this malignancy.

Apoptosis and immunophenotyping of peripheral blood lymphocytes in Iranian COVID-19 patients: Clinical and laboratory characteristics

A novel member of human coronavirus, named severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has been recently recognized in China and rapidly spread worldwide. Studies showed the decreasing of peripheral blood lymphocytes in a majority of patients. In this study, we have reported the clinical features, laboratory characteristics, the frequency of peripheral blood lymphocyte subpopulations, and their apoptosis pattern in Iranian coronavirus infectious disease (COVID-19) patients. Demographic and clinical data of 61 hospitalized confirmed cases with COVID-19 at Imam Khomeini Hospital were collected and analyzed. Peripheral blood mononuclear cells were isolated from all samples and the apoptosis pattern was evaluated using Annexin V/propidium iodide method. The frequency of lymphocyte subsets, including T-CD4⁺ , T-CD8⁺ , NK, B cells, and monocytes, was measured in all patients and 31 controls by flow cytometry. Our findings demonstrated that the percentage of lymphocytes, CD4⁺ , and CD8⁺ T cells were decreased in COVID-19 patients compared with the control group. Regarding the clinical severity, the number of lymphocytes, CD4⁺ , CD8⁺ T cells, and NK cells were also decreased in severe cases when compared with mild cases. Finally, our data have also indicated the increase in apoptosis of mononuclear cells from COVID-19 patients which was more remarkable in severe clinical cases. The frequency of immune cells is a useful indicator for prediction of severity and prognosis of COVID-19 patients. These results could help to explain the immunopathogenesis of SARS-CoV-2 and introducing novel biomarkers, therapeutic strategies, and vaccine candidates.

Expression Analysis of Fyn and Bat3 Signal Transduction Molecules in Patients with Chronic Lymphocytic Leukemia

BACKGROUND

Chronic lymphocytic leukemia (CLL) is correlated with defects in T-cell function resulting imparity in antitumor immune responses. Tim-3 is a co-inhibitory immune checkpoint receptor expressed on exhausted T-cells during tumor progression. Fyn and Bat3 are two important adaptor molecules involved in inhibition and activation of Tim-3 downstream signaling, respectively. In this study, the expression of Tim-3, Fyn, and Bat3 mRNA was evaluated in CLL patients.

METHODS

Peripheral blood mononuclear cells (PBMCs) were isolated from 54 patients with CLL and 34 healthy controls. Total RNA was extracted from all samples and applied for cDNA synthesis. The relative expression of Tim-3, Fyn, and Bat3 mRNA was determined by TaqMan Real-Time PCR using GAPDH as an internal control.

RESULTS

Tim-3 mRNA expression was not significantly different between CLL patients and healthy controls. Fyn mRNA expression was significantly lower in CLL patients and conversely, Bat3 mRNA expression was higher in CLL patients compared to healthy controls. Interestingly, the mRNA expression of Fyn inhibitory adaptor molecule was remarkably associated with expression of Tim-3 in CLL patients.

CONCLUSION

We have highlighted for the first time the expression of Fyn and Bat3 adaptor molecules in CLL patients. Our data demonstrated the strong correlation between the expression of Tim-3 and Fyn inhibitory molecules in CLL implying an important role for Tim-3-Fyn cooperation in induction of T-cell exhaustion.

Expression analysis of PD-1 and Tim-3 immune checkpoint receptors in patients with vitiligo; positive association with disease activity

The contribution of immune checkpoint receptors in the immunopathogenesis of various autoimmune diseases has been addressed in previous reports. In this study,  the expression profile of T-cell immunoglobulin and mucin-domain containing-3 (Tim-3) and programmed cell death-1 (PD-1) checkpoint molecules was investigated in CD8⁺ T cells of Vitiligo patients. The association of Tim-3 and PD-1 expression with disease activity was also explored. The frequency of Tim-3⁺ /PD-1⁺ /CD8⁺ T cells in 30 patients with vitiligo and 30 sex- and age-matched controls was determined by flow cytometry. CD8⁺ T cells were then positively isolated by magnetic beads, and the mRNA expression of PD-1 and Tim-3 was determined by TaqMan-based real-time PCR. To measure the cytokines production, PBMCs were stimulated with PMA/ionomycin and concentrations of IL-4, IFN-γ and TNF-α were measured in culture supernatants by ELISA. Disease activity of patients with vitiligo was determined using the Vitiligo Area Severity Index. Patients with vitiligo have significantly shown more expression of Tim-3 and PD-1 on their CD8⁺ T cells compared with controls. Expression analysis of Tim-3 mRNA, but not PD-1, confirmed the results obtained from flow cytometry. While the production levels of TNF-α and IFN-γ were found higher by patients with vitiligo, IL-4 production was lower in patients compared with controls. A direct association was observed between the Tim-3 and PD-1 expression and also the production of pro-inflammatory cytokines with disease activity of patients with vitiligo. Our results indicate that Tim-3 and PD-1 are involved in immune dysregulation mechanisms of CD8⁺ T cells in vitiligo and may introduce as potential biomarkers for disease progression and targeted immunotherapy.

Correction to: The synergistic effect of mefenamic acid with ionizing radiation in colon cancer

The original version of this article unfortunately contained a mistake. The name of "Zohreh Noaparast" is now corrected in the author group of this article.

Cellular apoptosis: An alternative mechanism of action for caspofungin against Candida glabrata

Background and Purpose:

Although the mechanism of action for echinocandins is known, the physiological mechanisms by which these antifungal agents cause cell death via the classical apoptotic pathways are not well-defined yet. Regarding this, the present study aimed to evaluate the mechanisms of caspofungin-induced Candida glabrata cell death.

Materials and Methods:

For the purpose of the study, the minimum inhibitory concentration (MIC) of caspofungin against C. glabrata (ATCC 90030) was determined using the broth microdilution reference method (CLSI M27-A2 and M27-S4). The annexin V and propidium iodide staining was performed to determine the way through which caspofungin acts against C. glabrata (i.e., through the induction of apoptosis and/or necrosis). Additionally, the possible effect of caspofungin on inducing the expression of two apoptotic genes, namely MCA1 and NUC, was studied using the real-time polymerase chain reaction assay.

Results:

According to the obtained MIC value (0.5 µg/mL), C. glabrata, exposed to 0.25, 0.5, and 1 µg/mL of caspofungin, exhibited the features of late apoptosis/necrosis after 18 h of incubation. Furthermore, the use of 0.25, 0.5, and 1 µg/ml caspofungin induced apoptosis (early/late) in 14.67%, 17.04%, and 15.89% of the cells, respectively. The results showed a significant difference between the percentages of early-apoptotic cells at the three concentrations (P<0.05). In addition, the rate of necrosis was significantly greater than that of apoptosis in response to caspofungin. Accordingly, necrosis occurred in 71.26%, 71.26%, and 61.26% of the cells at the caspofungin concentrations of 0.25, 0.5, and 1 µg/mL, respectively (P<0.05). The analysis of the data in the REST software demonstrated a significant increase in the expression of MCA1 and NUC1 genes (P<0.05).

Conclusion:

As the findings of the present study indicated, caspofungin promoted both necrosis and apoptosis of C. glabrata cells at concentrations higher than or equal to the MIC value.

In vitro and in vivo evaluation of kojic acid against Toxoplasma gondii in experimental models of acute toxoplasmosis

As current toxoplasmosis chemotherapies have many side effects along with toxicity on patients, we examined the anti-Toxoplasma effect of a biologically important natural antibiotic, kojic acid, in vitro and in vivo. Vero cells were incubated with different concentrations of kojic acid or pyrimethamine (positive control), and the cellular viability was determined. Next, Vero cells were infected with T. gondii (RH strain) and treated with drugs. Then, we calculated the infection index, T. gondii intracellular proliferation and the number and measure of plaque. Moreover, the effect of kojic acid on survival times, serum levels of IFN-γ and TNF-α and histopathological changes in the liver and spleen of Balb/c mice infected with T. gondii were determined. Kojic acid reduced the infection index, intracellular proliferation, the number and measure of plaque in vitro when compared to untreated infected cells. Kojic acid (100 mg/kg/day) also showed a better survival rate than infected untreated control mice (P < 0.05). IFN-γ and TNF-α secretions were significantly increased by kojic acid treatment in comparison to untreated groups (P < 0.05). In addition, its inhibitory effects on inflammatory alterations, apoptosis, and necrosis have been shown in sections of liver and spleen. We conclude that kojic acid exhibit potent anti-Toxoplasma activity with direct and indirect effects on the parasite, although further studies are needed before consideration of clinical trials.

Dysregulated Expression of Tim-3 and NKp30 Receptors on NK Cells of Patients with Chronic Lymphocytic Leukemia

BACKGROUND

In this study, the expression pattern of NKp30 and T cell immunoglobulin and mucin domain-containing molecule-3 (Tim-3), as candidates for activating and inhibitory receptors of NK cells, were evaluated in patients with chronic lymphocytic leukemia (CLL).

PATIENTS AND METHODS

24 CLL patients and 19 healthy controls were enrolled. Fresh peripheral blood was collected from all subjects and stained with fluorochrome-conjugated antibodies. The frequency of CD56+/CD3-/NKp30+ and CD56+/CD3-/Tim-3+ cells was determined by multicolor flow cytometry.

RESULTS

Our results revealed that Tim-3 is significantly upregulated on natural killer (NK) cells of CLL patients in comparison to healthy controls. NK cells of CLL patients showed lower expression of NKp30-activating receptor compared to controls. Tim-3 expression pattern on NK cells of CLL patients was correlated with poor prognostic factors including low hemoglobin level, high absolute lymphocyte count, and high serum C-reactive protein level.

CONCLUSION

Dysregulated expression of Tim-3 and NKp30 receptors confirms the exhaustion state of NK cells in CLL. Our data introduce Tim-3 as a promising biomarker and potential target for immunotherapy of CLL.

Prevalence of specific immunoglobulin E and G against Aspergillus fumigatus in patients with asthma

Background and Purpose

Aspergillus fumigatus as a ubiquitous fungus can be found in the respiratory tract of the asthmatic and healthy people. The inhalation of Aspergillus spores leads to an immune response in individuals with asthma and results in the aggravation of the clinical symptoms. The present study aimed to investigate the prevalence of specific immunoglobulin E and G (IgE and IgG) against A.fumigatus in asthmatic patients.

Materials and Methods

This study was conducted on 200 consecutive patients with moderate to severe asthma referring to Masih Daneshvari hospital Tehran, Iran, from January 2016 to February 2018. Skin prick test (SPT) was performed in all subjects with Aspergillus allergens. Moreover, all patients underwent specific IgE testing for Aspergillus using Hycor method. Enzyme immune assay was applied to measure total IgE and Aspergillus-specific IgG.

Results

According to the results, the mean age of the patients was 45.8 years (age range: 18-78 years). The mean levels of total IgE and Aspergillus specific IgE in asthmatic patients were obtained as 316.3 (range: 6-1300 IU/ml) and 1.5 (range: 0.1-61.3 IU/ml), respectively. Out of 200 patients, 27 (13.5%), 65 (32.5%), 22 (11.0%), and 86 (43.0%) cases had positive Aspergillus SPT, total IgE of > 417 IU/ml, Aspergillus -specific IgE, and IgG, respectively. The level of these variables in patients with severe asthma were 16 (16.5%), 36 (37.1%), 15 (15.5%), and 46 (47.4%), respectively.

Conclusion

As the findings indicated, reactivity to Aspergillus is a remarkable phenomenon in asthmatic patients. It is also emphasised that the climatic condition may affect the positive rate of hypersensitivity to Aspergillus.

Elevated Expression of Tim-3 and PD-1 Immune Checkpoint Receptors on T-CD4+ Lymphocytes of Patients with Asthma

Asthma is a chronic disorder of the airways characterized by reversible airflow obstruction, inflammation and bronchial hyperresponsiveness. Different immune cells and molecules have been attributed to involve in pathogenesis of asthma. In the current case-control study, the expression of T cell Ig and mucin domain-containing molecule-3 (Tim-3) and programmed death-1 (PD-1) was studied on CD4+ T cells of patients with asthma and normal controls. The frequency of Tim-3+/PD-1+/CD4+ T cells was determined by a three color flow cytometry method in 37 patients with asthma and 32 healthy controls. To evaluate the Th1/Th2 ratio, peripheral blood mononuclear cells were isolated from all samples and stimulated with phorbol 12- myristate 13- acetate ( PMA)/ionomycin for 18 h. IFN-γ) and Interleukin-4 (IL-4) were measured in culture supernatants by-(ELISA). Serum total immunoglobulin E (IgE) was also measured in all samples. Significant increase in percentage and absolute count of Tim-3+/PD-1+/CD4+, Tim-3+/CD4+ and PD-1+/CD4+ T cells was found in asthmatic patients compared to healthy controls (p=0.02 and p=0.003, respectively). The IFN-γ/IL-4 ratio (Th1/Th2 ratio) was significantly higher in healthy controls than that of asthmatic patients (p=0.029). Our data regarding the increased expression of PD-1 and Tim-3 on CD4+ T cells of patients with asthma suggest the potential roles of these immune checkpoint receptors in immune dys-regulation of asthma.

Anti-inflammatory effects of the Portulaca oleracea hydroalcholic extract on human peripheral blood mononuclear cells

Background: Portulaca oleracea, known as Purslane, is an annual growing herb with wide distribution around the world and traditionally used to manage several diseases. Different therapeutic properties as an anti-fever agent as well as anti-inflammatory and analgesic effects have been attributed to P. oleracea. The aim of this study was to investigate the effects of P. oleracea aerial extract on production of pro- and anti-inflammatory cytokines by human peripheral blood mononuclear cells (PBMCs). Methods: Aerial parts of P. oleracea (stems and leaves) were collected and extracted by percolation using methanol. The optimal and non-cytotoxic dose of hydro-alcoholic extract for cell culture analysis was determined by MTT assay. To assess the antiinflammatory effects of P. oleracea, PBMCs obtained from 12 normal volunteers were cultured in RPMI complete medium and cotreated with E. coli lipopolysaccharide (LPS) and P. oleracea hydro-alcoholic extract. Following 18-hour incubation, culture supernatants were harvested for measurement of secreted TNF-α, IL-6 and IL-10 by ELISA. Statistical analyses were performed using the SPSS v.20, and data analyzed by Kolmogorov-Smirnov, Mann-Whitney U, Kruskal-Wallis and post Hoc tests. P-values<0.05 were considered significant. Results: The optimal non-cytotoxic concentration of P. oleracea aerial extract was defined as 100 μg/ml based on MTT viability assay. P. oleracea hydro-alcoholic extract significantly decreased the concentration of both pro-inflammatory cytokines TNF-α and IL-6 in LPS-stimulated PBMCs (p<0.001 and p<0.001, respectively). However, the concentration of IL-10 as an anti-inflammatory cytokine, did not show any statistically significant change (p=0.390). Conclusion: Our findings highlighted the potential anti-inflammatory properties of P. oleracea in herbal medicine. Future analysis on different constituents of total extract may confirm its therapeutic effects as a promising anti-inflammatory compound.

Th1-Th17 Ratio as a New Insight in Rheumatoid Arthritis Disease

The Th17, Th1 and dual Th17/Th1 cells are important players in rheumatoid arthritis (RA) disease. To assess their roles, the frequency and impact of these cells were investigated in patients with different disease activity. In 14 new cases and 41 established RA patients in comparison with 22 healthy controls, the percentages of Th17, Th1 and dual Th17/Th1 cells were determined by flow-cytometry and their correlations were investigated with disease activity score (DAS28). Moreover, serum levels of IL-6 and IL-17 as inducer and functional cytokines for Th17 were investigated. Finally, serum levels of anti citrullinated protein antibody (ACPA) and rheumatoid factor (RF) were assessed. Percentage of Th17 cells in RA patients were increased in comparison with healthy controls (p<0.01). In correlation with this finding, IL-17 and IL-6 cytokines in RA patients also increased (p<0.01). The Th1 cells in RA patients were less than healthy group (p<0.05) and showed negative correlation with disease activity (r=-0.328, p<0.01). Dual Th17/Th1 cell only in new cases of RA were more than healthy control groups (p<0.01). The Th1/Th17 ratio in RA patients is statistically different with healthy control group (p<0.01) and it has negative correlation with disease activity (r=-264, p<0.05). The levels of ACPA and RF were increased with disease progression. Decreasing of Th1/Th17 ratio in RA patient suggested a new paradigm in the field of autoimmune disease and indicated that imbalance or plasticity between these subsets can be important in progress, diagnosis and therapy of RA disease.

Radiosensitizing Effect of Cerium Oxide Nanoparticles on Human Leukemia Cells

BACKGROUND

Radiotherapy is an important protocol in the treatment of cancers, but radioresistance of cancerous cells is a challenge in cancer treatment.

OBJECTIVE

The aim of this study was to evaluate the radiosensitizing effect of Cerium oxide Nanoparticles (CNPs) on human promyelocytic leukemia cells (HL-60).

METHOD

HL-60 cells were treated with CNPs at different concentrations (10-100 μg/ml) and exposed to Ionizing Radiation (IR). The genotoxicity effects of CNPs or/and IR were assessed by micronuclei assay in HL-60 cells.

RESULTS

It was found that CNPs increased the frequencies of micronuclei in HL-60 cells. CNPs pretreatment to irradiation significantly increased the IR-induced micronuclei incidences in HL-60 cells. The present study demonstrates CNPs to be an effective sensitizer on DNA damage induced by IR in HL-60 cells.

CONCLUSION

These findings suggest the potential application of CNPs as a highly effective radiosensitizer for the treatment of leukemia.

CD4+ T Cells are Exhausted and Show Functional Defects in Chronic Lymphocytic Leukemia

BACKGROUND

Chronic lymphocytic leukemia (CLL) is the most common adult leukemia in the western world. This health problem is caused due to the accumulation of mature B-lymphocytes in the peripheral blood and bone marrow. In the course of cancer, CD4+ T cells become "exhausted" and characterized with poor effector functions and the expression of multiple inhibitory receptors.

OBJECTIVE

To investigate the frequency and functional properties of exhausted CD4+ T lymphocytes in patients with CLL.

METHODS

Peripheral blood mononuclear cells were obtained from 25 untreated CLL patients and 15 healthy volunteers. CLL patients were clinically classified according to the Rai staging system. The frequency of CD4+/Tim-3+/PD-1+ cells was obtained by flow cytometry. To evaluate cell proliferation and cytokine production, CD4+ T cells were isolated and stimulated with phytohemagglutinin and PMA/ionomycin. Concentrations of IL-2, IFN-γ, TNF-α, and IL-10 were measured in the culture supernatants of stimulated cells by the ELISA technique.

RESULTS

The percentage of CD4+/Tim-3+/PD-1+ cells was significantly higher in CLL patients than that of healthy controls. CD4+ T cells from CLL patients showed lower proliferative responses, a lower production of IL-2, IFN-γ, and TNF-α, and a higher production of IL-10, compared to healthy controls. CD4+ T cells from CLL patients in advanced clinical stages showed more exhaustion features than those of early stages.

CONCLUSION

Given that the exhaustion phase of T cells can be reversible, targeted blocking of immune inhibitory molecules could be a promising tool to restore the host immune responses against leukemic cells in CLL.

Upregulation of Galectin-9 and PD-L1 Immune Checkpoints Molecules in Patients with Chronic Lymphocytic Leukemia

Background: Deviation of host immune response by engagement of inhibitory receptors is one of the well-known mechanisms of tumor cells for immune evasion and survival. PD-1/PD-L1 and Tim-3/Gal-9 axes are two major pathways in this area which their contribution has been documented in a variety of malignancies. In this study, Gal-9 and PD-L1 expression was investigated in leukemic cells from patients with Chronic Lymphocytic Leukemia (CLL). Methods: Peripheral blood mononuclear cells (PBMCs) were obtained from 25 untreated CLL patients and 15 sex- and age-matched healthy controls. CLL patients were classified into different clinical stages based on the Rai staging system. Total RNA was extracted from all samples and applied for cDNA synthesis. Relative expression of Gal-9 and PD-L1 mRNA was determined by Real-Time PCR using β-actin as a housekeeping gene. Results: Gal-9 and PD-L1 mRNA was significantly more expressed in CLL patients compared to healthy controls (p<0.0001 and p=0.005, respectively). CLL patients in advanced clinical stages showed higher expression of Gal-9 and PD-L1 in comparison to patients in early clinical stages (p<0.0001 and p=0.004, respectively). Conclusion: Our promising results regarding over-expression of Gal-9 and PD-L1 in CLL patients call future complementary studies to more evaluate and confirm these pathways for immunotherapy approaches of this malignancy. Upregulation of both Gal-9 and PD-L1 in CLL patients with advanced clinical stages introduces them as useful prognostic biomarkers for disease progression.

Frequency and functional characterization of exhausted CD8+ T cells in chronic lymphocytic leukemia

OBJECTIVES

The phenotypic and functional properties of Tim-3⁺ /PD-1⁺ /CD8⁺ cells as exhausted T cells were investigated in chronic lymphocytic leukemia (CLL).

METHODS

Frequency of CD8⁺ /Tim-3⁺ /PD-1⁺ exhausted cells was determined by flow cytometry. For functional analysis, magnetic beads-isolated CD8⁺ T cells were stimulated with PHA and PMA/ionocymin to assess their proliferative responses and cytokine production by MTT and ELISA, respectively. Cytotoxic activity of isolated CD8⁺ T cells was determined using CD107a degranulation assay.

RESULTS

The proportion of exhausted CD8⁺ T cells was significantly higher in CLL compared to controls. Isolated CD8⁺ T cells from CLL showed functional defects in proliferation, degranulation, and cytokines production. While IL-2, TNF-α, and IFN-γ were significantly lower in CLL patients, IL-10 was higher in the patients group. Patients with progressive clinical stages showed higher frequency and dysfunction of exhausted CD8⁺ T cells.

CONCLUSION

Targeting immune inhibitory receptors to restore the function of tumor surrounding T cells could be helpful for immunotherapy of CLL.