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.

Three-dimensional bioengineered dermal derived matrix scaffold in combination with adipose-derived stem cells accelerate diabetic wound healing.

Due to the multifactorial nature of diabetic wounds, the most effective treatments require combinatorial approach. Herein we investigated whether engraftment of a bioengineered three-dimensional dermal derived matrix scaffold (DDMS) in combination with adipose-derived stem cells (ADSs), could accelerate diabetic wound healing. Diabetic animals were randomly planned into the control group, DDMS group, ADS group, and DDMS+ADS group. On days 7, 14, and 21, tissue samples were obtained for stereological, molecular, and tensiometrical assessments. We found that the wound contraction rate, the total volumes of new epidermis and dermis, the numerical densities of fibroblasts and blood vessels, collagen density, and tensiometrical parameters were meaningfully greater in the treated groups than in the control group, and these changes were more obvious in the DDMS+ADS ones (p < 0.05). Moreover, the expression of TGF-ß, bFGF, and VEGF genes were considerably upregulated in treated groups compared to the control group and were greater in the DDMS+ADS group (p < 0.05). This is while expression of TNF-α and IL-1ß, as well as the numerical densities of neutrophils and macrophages decreased more considerably in the DDMS+ADS group than in the other groups (p < 0.05). Overall, it was found that using both DDMS engraftment and ADS transplantation has more impact on diabetic wound healing.

Coenzyme Q10 attenuates neurodegeneration in the cerebellum induced by chronic exposure to tramadol.

BACKGROUND: Chronic use of tramadol can cause neurotoxic effects and subsequently cause neurodegeneration in the cerebellum. The main damage mechanisms identified are oxidative stress and inflammation. Currently, we investigated the effects of coenzyme Q10 (CoQ10) in attenuates of neurodegeneration in the cerebellum induced by chronic exposure to tramadol. MATERIAL AND METHODS: Seventy-two male mature albino rats were allocated into four equal groups, including; non-treated group, CoQ10 group (which received CoQ10 at 200 mg/kg/day orally for three weeks), tramadol group (which received tramadol hydrochloride at 50 mg/kg/day orally for three weeks), and tramadol+CoQ10 group (which received tramadol and CoQ10 at the same doses as the previous groups). Tissue samples were obtained for stereological, immunohistochemical, biochemical, and molecular evaluations. Also, functional tests were performed to evaluate behavioral properties. RESULTS: We found a significant increase in stereological parameters, antioxidant factors (catalase, glutathione, and superoxide dismutase), and behavioral function scores in the tramadol+CoQ10 group compared to the tramadol group (p < 0.05). In addition, malondialdehyde levels, the density of apoptotic cells, as well as the expression of pro-inflammatory (tumor necrosis factor-alpha, interleukin 1 beta, and interleukin 6) and autophagy (lysosome-associated membrane protein 2, autophagy-related 5, beclin 1, and autophagy-related 12) genes were considerably reduced in the tramadol+CoQ10 group compared to the tramadol group (p < 0.05). CONCLUSION: We conclude that the administration of CoQ10 has neuroprotective effects in the cerebellum of rats that have chronic exposure to tramadol.

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.

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.

Exosomes derived from human adipose mesenchymal stem cells loaded bioengineered three-dimensional amniotic membrane-scaffold-accelerated diabetic wound healing.

The occurrence of wounds and defects in the healing process is one of the main challenges in diabetic patients. Herein, we investigated whether adipose-derived stem cells (ADSCs)-derived exosomes loaded bioengineered micro-porous three-dimensional amniotic membrane-scaffold (AMS) could promote healing in diabetic rats. Sixty diabetic rats were randomly allocated into the control group, exosome group, AMS group, and AMS + Exo group. On days 7, 14, and 21, five rats from each group were sampled for stereological, immunohistochemical, molecular, and tensiometrical assessments. Our results indicated that the wound closure rate, the total volumes of newly formed epidermis and dermis, the numerical densities of fibroblasts and proliferating cells, the length density blood vessels, collagen density as well as tensiometrical parameters of the healed wounds were considerably greater in the treated groups than in the control group, and these changes were more obvious in the AMS + Exo ones. Furthermore, the expression of TGF-ß, bFGF, and VEGF genes was meaningfully upregulated in all treated groups compared to the control group and were greater in the AMS + Exo group. This is while expression of TNF-α and IL-1ß, as well as cell numerical densities of neutrophils, M1 macrophages, and mast cells decreased more considerably in the AMS + Exo group in comparison with the other groups. Generally, it was found that using both AMS transplantation and ADSCs-derived exosomes has more effect on diabetic wound healing.

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 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.

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.

Association between Human Papillomavirus and Oral Cancer in Iranian Clinical Samples: A Meta-Analysis Review.

Background: Oral squamous cell carcinoma (OSCC) is one of the most common malignancies and is a serious problem worldwide. The role of HPV in oral cavity squamous cell carcinoma has been studied in several researches. This present review and meta-analysis aimed to investigate the relation between human papillomavirus (HPV) and oral cancer. Methods: Relevant studies were found using online international databases including Science direct, Web of science (ISI), PubMed, Scopus, Embase, and Google scholar, to determine relevant studies published between 2000 and Jan 2020. Suitable studies were selected and assessed by two independent researchers. The quality of all papers were determined by a checklist. Heterogeneity assay among the primary studies was evaluated by Cochran's Q test and I2 index. The statistical analyses were done using Stata SE, V.11 software. Trim and Fill method was applied to confirm the validity of the results. Results: This meta-analysis consists of 8 primary studies on the incidence of HPV infection in Iranian patients with oral diseases. The odds ratio between HPV infection and risk of oral cancer was 4.00 (95%CI: 2.31, 6.93). Conclusion: This meta-analysis showed associations between prevalence of HPV infection and oral cancer among Iranian patients. The chance of developing oral cancer among HPV positive patients was higher than that in HPV negative patients.

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.

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.

Up-regulation of human immune system function by Donkey's Milk

Donkey's milk represents a good alternative to human milk because of its chemical characteristics similar to those of human's. In present study, the pro- and anti-inflammatory effects of donkey's milk were evaluated on peripheral blood mononuclear cells (PBMCs). PBMCs were isolated from 12 young and 12 aged normal subjects. PBMCs were cultured with or without the optimal and non-cytotoxic dose of pasteurized donkey's milk, and polymyxin B was used to inhibit the possible endotoxin contamination. Following 18 hours incubation, culture supernatants were harvested to measure the secreted Tumor necrosis factor-α (TNF-α), Interleukin-6 (IL-6), Interleukin-8 (IL-8) and Interleukin-10 (IL-10) by ELISA. Donkey's milk significantly increased TNF-α (p= 0.01), IL-8 (p< 0.0001), IL-6 (p< 0.0001) and IL-10 (p= 0.01) levels in PBMCs. In addition, the levels of IL-6 (p= 0.002), IL-8 (p= 0.002) and TNF-α (p= 0.002) from aged subjects were significantly higher compared with young subjects. In contrast with these data, the level of IL-10 was markedly reduced from aged subjects (p= 0.02). Considering the immune-potentiation effects of donkey's milk, it is suggested investigating milk as a beneficial dietary component for up-regulating the immune response in aged people

Protective effect of TSLP and IL-33 cytokines in ulcerative colitis.

PURPOSE: Inflammatory bowel disease (IBD) primarily includes ulcerative colitis (UC) and Crohn's disease (CD). Thymic stromal lymphopoietin (TSLP) is a cytokine produced by intestinal epithelial cells (IECs) with immunomodulatory properties that plays an important role in the development of regulatory T cell (Treg) responses and tolerance in the gut. On the other hand, IL-33 has been considered as a cytokine with two different properties, inflammatory and anti-inflammatory functions, the latter may play a protective role against chronic intestinal inflammation. In the present study, we investigated the relative gene expression levels of TSLP and IL-33 molecules in ulcerative colitis. METHODS: Patients with clinical symptoms of colitis undergoing a routine diagnostic colonoscopy were included in this study. Biopsy specimens were collected and divided into two parts. One part was fixed and processed for routine histopathological examinations and the other part was stored for RNA extraction. TSLP and IL-33 gene expression were determined using the SYBR Green qRT-PCR. RESULTS: The expression level of TSLP and IL-33 were significantly lower in UC patients compared with the control group. Moreover, the expressions of these cytokines were more down-regulated in severe UC patients compared with mild and moderate ones and the control group. We also showed a positive correlation between low expression of TSLP and IL-33 and the severity of UC disease. CONCLUSIONS: In this study, we showed decreased mRNA expression levels of TSLP and IL-33 in UC patients and also a negative correlation between expression of TSLP and IL-33 and severity of UC disease.

Over-Expression of Immunosuppressive Molecules, PD-L1 and PD-L2, in Ulcerative Colitis Patients.

BACKGROUND: Ulcerative colitis (UC) and Crohn's disease (CD) are the two forms of inflammatory bowel disease (IBD). Adaptive immune responses involving helper T cells play an important role in developing IBDs. Programmed death (PD)-1 and its ligands namely PD-L1 and PD-L2 are negative costimulatory molecules that control T cell motility and formation of an immune synapse between T cells and antigen-presenting cells (APCs). OBJECTIVE: To investigate the role of PD-L1 and PD-L2 in patients with UC to clarify the mechanism of IBD development. METHODS: Biopsy specimens were obtained from 50 UC patients and 45 sex- and age-matched control subjects. Total RNA was extracted from all samples and applied for cDNA synthesis. Relative expression of PD-L1 and PD-L2 mRNA was determined using Taqman qRT-PCR. RESULTS: Relative gene expression levels of both PD-L1 and PD-L2 were higher in UC patients than the control groups (p<0.05 and p<0.01, respectively). Furthermore, both PD-L1 and PD-L2 expressions were positively correlated in all study subjects (r=0.339, p<0.001). However, among the groups with disease severity, the relative gene expression levels of PD-L1 and PD-L2 showed no significant difference. CONCLUSIONS: During IBD, the occurrence of PD-L1 and PD-L2 up-regulation may modulate the chronic inflammation of colonic mucosa.

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.

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 ß-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.