Qianshan Tao

miR-29b and miR-29c Are Involved in Toll-Like Receptor Control of Glucocorticoid-Induced Apoptosis in Human Plasmacytoid Dendritic Cells

Glucocorticoids (GCs) are frequently used to treat many of the acute disease manifestations associated with inflammatory and autoimmune disorders. However, Toll-like receptor (TLR) pathway-activated plasmacytoid dendritic cells (pDCs) are resistant to GC-induced apoptosis, which leads to the inefficiency of GCs in the treatment of type I interferon-related autoimmune diseases, such as systemic lupus erythematosus (SLE). Therefore, compounds promoting pDC apoptosis may be helpful for improving the efficacy of GCs. In this study, we performed screening to identify microRNAs (miRNAs) involved in TLR-inhibited GC-induced pDC apoptosis and found an array of miRNAs that may regulate pDC apoptosis. Among those demonstrating altered expression, 6 miRNAs were inhibited in TLR-activated pDCs. Bioinformatics analysis and functional studies indicated that miR-29b and miR-29c were 2 key miRNAs involved in TLR-inhibited GC-induced pDC apoptosis. Furthermore, both of these miRNAs promoted pDC apoptosis by directly targeting Mcl-1 and Bcl-2 in human primary pDCs. Our findings provide new targets that could improve the efficacy of GCs for the treatment of SLE.

IL-15 improves the cytotoxicity of cytokine-induced killer cells against leukemia cells by upregulating CD3+CD56+ cells and downregulating regulatory T cells as well as IL-35.

Cytokine-induced killer (CIK) cells are usually generated from peripheral blood mononuclear cells with the stimulation of IL-2 in vitro. Unlike the conventional IL-2-stimulated CIK cells (IL-2-CIK cells), we investigated the characteristics and potential mechanism of IL-15-stimulated CIK cells (IL-15-CIK cells) in this study. Compared with IL-2-CIK cells, the percentage of CD3+CD56+ cells was significantly increased in IL-15-CIK cells, but the expression of regulatory T (Treg) cells and IL-35 was significantly decreased in IL-15-CIK cells. Meanwhile, the in vitro cytotoxicity against human myeloid leukemia cells K562 of IL-15-CIK cells was significantly augmented compared with IL-2-CIK cells. These data suggest that IL-15 may improve the cytotoxicity of CIK cells against leukemia cells by upregulating CD3+CD56+ cells and downregulating Treg cells and IL-35.

Tumor-induced CD14+HLA-DR−/low myeloid-derived suppressor cells correlate with tumor progression and outcome of therapy in multiple myeloma patients

Myeloid-derived suppressor cells (MDSCs) are heterogeneous, immature, myeloid progenitor cells, which suppress immune responses against tumors. CD14+HLA-DR−/low monocytic MDSCs (M-MDSC) are increased in patients suffering from multiple myeloma (MM). However, the frequency and function of M-MDSCs with the relationship between the tumor development and outcome of therapy in MM remain unclear. In this study, we analyzed the changes in M-MDSCs in newly diagnosed, relapsed and remission MM patients. In addition, we also assessed the response of M-MDSCs in MM patients treated with a bortezomib-based therapy as well as the impact of bortezomib on the modulation of M-MDSCs in vitro. The levels of M-MDSCs in newly diagnosed and relapsed MM patients were significantly increased compared with those in remission MM patients and healthy donors. Moreover, the levels of M-MDSCs were shown to correlate with tumor progression. The decrease in M-MDSCs after proteasome inhibitory therapy suggested that M-MDSCs could be considered as an indicator for the efficacy of therapy. Finally, we found the plasma from newly diagnosed MM patients, and MM cells were able to induce the accumulation of M-MDSCs in vitro. These results indicated that M-MDSCs could be considered as a prognostic predictor and an important cell type contributing to immune suppressive microenvironment in MM patients. Treatments targeting for M-MDSCs may improve therapeutic outcomes for MM patients.

Dendritic cells decreased the concomitant expanded Tregs and Tregs related IL-35 in cytokine-induced killer cells and increased their cytotoxicity against leukemia cells.

Regulatory T cells (Tregs) are potent immunosuppressive cells and essential for inducing immune tolerance. Recent studies have reported that Tregs and Tregs related cytokines can inhibit the antitumor activity of cytokine-induced killer (CIK) cells, but dendritic cells co-cultured CIK (DC-CIK) cells can be used for induction of a specific immune response by blocking of Tregs and TGF-β, IL-10. As a novel identified cytokine, IL-35 is specially produced by Tregs and plays an essential role in immune regulation. However, it remains unknown whether IL-35 roles in tumor immunotherapy mediated by CIK and DC-CIK cells. In this study, we cultured CIK and DC-CIK cells from the same healthy adult samples, and investigated their phenotype, proliferation, cytotoxic activity against leukemia cell lines K562 and NB4 by FCM and CCK-8, measured IL-35, TGF-β and IL-10 protein by ELISA, detected Foxp3, IL-35 and IL-35 receptor mRNA by Real-time PCR, respectively. We found Tregs and IL-35 concomitantly expanded by a time-dependent way during the generation of CIK cells, but DC significantly down-regulated the expression of them and simultaneously up-regulated the proliferation ability as well as cytotoxic activity of CIK cells against leukemia cell lines. Therefore, our data suggested that DC decreased concomitant expanded Tregs and Tregs related IL-35 in CIK cells and might contribute to improve their cytotoxicity against leukemia cells in vitro.

Regulatory T cells‐derived IL‐35 promotes the growth of adult acute myeloid leukemia blasts

Tumor immune escape mechanism mediated by CD4+CD25+regulatory T cells (Tregs) is a key factor in the pathogenesis of acute myeloid leukemia (AML). IL‐35, as a novel inhibitory cytokine, is produced by Tregs specially and regulates functions of Tregs in murine. However, IL‐35 expression of Tregs in human is still disputed, and its role in AML is yet to be elucidated. In this study, we found that IL‐35 was expressed highly in peripheral blood plasma of adult patients with AML and significantly correlated with the clinical stages of malignancy. Tregs‐derived from adult AML patients produced IL‐35 in a stimulation‐dependent manner. IL‐35 promoted AML blasts immune escape by expanding Tregs and inhibiting CD4+CD25‐effector T cells (Teffs). Furthermore, IL‐35 directly promoted the proliferation of AML blasts and reduced the apoptosis of AML blasts. Together, our study demonstrates that IL‐35‐derived from Tregs promotes the growth of adult AML blasts, suggesting that IL‐35 has an important role in the pathogenesis of AML.

Absence of both CD56 and CD117 expression on malignant plasma cells is related with a poor prognosis in patients with newly diagnosed multiple myeloma

We retrospectively evaluated the association between the expression of CD56 and CD117 on neoplastic plasma cells and patients prognosis in 50 newly diagnosed multiple myeloma (MM) patients. The overall survival (OS) was measured and Cox proportional hazards model was used to evaluate CD56 and CD117 as possible prognostic factors for OS. CD56+ and CD117+ were detected in 74% and 32% multiple myeloma cases, respectively. In Kaplan-Meier analysis, CD56 and CD117 expression demonstrated potential prognostic impacts and were associated with longer OS (CD56: p=0.004, CD117: p=0.022), absence of both of them showed significantly shorter OS (p=0.046 compared to CD56+/CD117+ group, p=0.014 compared to CD56-/CD117+ or CD56+/CD117- group). Multivariate analysis showed that CD56 was independently prognostic of longer OS (p=0.012). After induction chemotherapy, overall response rates (ORR) was higher in CD56-positive group compared to CD56-negative group (70.6% versus 30.0%, p=0.024), however, there was no difference between CD117-positive and CD117-negative group (69.2% versus 58.1%, p=0.448). This study demonstrated the prognostic value of CD56 and CD117 in patients with newly diagnosed MM patients. Absence of both of them was associated with the poorest prognosis.

Platelet desialylation correlates with efficacy of first-line therapies for immune thrombocytopenia

Immune thrombocytopenia (ITP) is a common autoimmune bleeding disorder. Despite considerable investigation, the pathogenesis of ITP remains incompletely understood, and for many patients, effective therapy is still unavailable. Using murine models and in vitro studies of human blood samples, we recently identified a novel Fc-independent platelet clearance pathway, whereby antibody-mediated desialylated platelets can be cleared in the liver via asialoglycoprotein receptors, leading to decreased response to standard first-line therapies targeting Fc-dependent platelet clearance. Here, we evaluated the significance of this finding in 61 ITP patients through correlation of levels of platelet desialylation with the efficacy of first-line therapies. We found that desialylation levels between different responses to treatment groups were statistically significant (p < 0.01). Importantly, correlation analysis indicated response to treatment and platelet desialylation were related (p < 0.01), whereby non-responders had significantly higher levels of platelet desialylation. Interestingly, we also found secondary ITP and certain non-ITP thrombocytopenias also exhibited significant platelet desialylation compared to healthy controls. These findings designate platelet desialylation as an important biomarker in determining response to standard treatment for ITP. Furthermore, we show for the first time platelet desialylation in other non-ITP thrombocytopenias, which may have important clinical implications and deserve further investigation.

Elevated IL-35 in bone marrow of the patients with acute myeloid leukemia

Acute myeloid leukemia (AML) is the most common hematological malignancy in adults, but the etiology of it remains poorly understood. IL-35 is a recently described cytokine composed of an IL-12 subunit p35 and an IL-27 subunit Epstein-Barr virus induced gene 3 (EBI3), and has an immunosuppressive effect on inflammation through induction of regulatory T cells (Tregs) and suppression of Th1 and Th17. Recently, we have illustrated that concentrations of IL-35 in peripheral blood are up-regulated in newly diagnosed (ND) AML patients. However, whether IL-35 in bone marrow is increased in AML patients is not clear. In this study, we examined IL-35 in bone marrow by various methods including RT-PCR, ELISA, FCM and IHC, and found that IL-35 levels are also increased significantly in bone marrow of adult AML patients. Furthermore, we investigated that concentrations of bone marrow IL-35 in ND group were higher than that in complete remission (CR) group and control group, but there was no significant difference compared to that in relapse group. In conclusion, IL-35 was elevated in bone marrow of adult AML patients and this increase was correlated with the clinical stages of malignancy, suggesting that IL-35 is involved in pathogenesis of AML.

A novel cellular senescence gene, SENEX, is involved in peripheral regulatory T cells accumulation in aged urinary bladder cancer.

Regulatory T cells (Tregs) play an essential role in sustaining self-tolerance and immune homeostasis. Despite many studies on the correlation between Tregs accumulation and age, or malignancies, the related mechanism hasn’t been well explored. To find out the mechanism of Tregs accumulation in aged urinary bladder cancer, we examined the novel cellular senesence gene SENEX and relevant apoptosis gene mRNA expression in sorted CD4+CD25hi Tregs from aged UBC donors, evaluated serum cytokine profiles related to tumor immunopathology, and further explored the relationship between SENEX expression, apoptosis gene expression and cytokine secretion. After having silenced down SENEX gene expression with RNA interference, we also evaluated the cellular apoptosis of Tregs sorted from aged UBC patients in response to H2O2-mediated stress. Our data indicated that upregulated SENEX mRNA expression in Tregs of aged UBC patients was correlated with pro-apoptotic gene expression and cytokine concentration. Silencing SENEX gene expression increased cellular apoptosis and pro-apoptotic gene expression of Tregs, in response to H2O2-mediated stress. Upregulated SENEX mRNA expression together with decreased pro-apoptotic gene expression and disturbances in cytokines synthesis may contribute to the Tregs proliferation and promote tumorigenesis and metastasis. Overall, upregulation of cellular senescence gene SENEX, was associated to regulatory T cells accumulation in aged urinary bladder cancer. Our study provides a new insight into understanding of peripheral Tregs accumulation in aged malignancies.

Targeting regulatory T cells in cytokine‑induced killer cell cultures (Review)

Regulatory T cells (Tregs) are potent immunosuppressive cells that promote tumor growth and invasion by inducing immune escape and suppressing the antitumor immune response. Cytokine-induced killer (CIK) cells are considered to be the primary candidate for adoptive immunotherapy due to their strong antitumor activity. It was recently reported that the concomitant presence of Tregs may decrease the cytotoxicity of CIK cells. Therefore, depletion or downregulation of Tregs in CIK cell cultures by optimizing the culture program may enhance CIK cell cytotoxicity in vitro and in vivo. The aim of the present review was to summarize the currently available studies on the optimal culture strategy for improving the antitumor activity of CIK cells through targeting Tregs.