Change in expression pattern of TCR–CD3 complex in patients with multiple myeloma

Key links in the physiological regulation of the immune system and disease induction: T cell receptor -CD3 complex

T cell receptor (TCR) is a kind of surface marker that are specific to T cells. The TCR regulates T cell function and participates in the body's immunological response to prevent immune dysregulation and inflammatory reactions by identifying and binding exogenous antigens. Due to its brief intracellular segment, TCR requires intracellular molecules to assist with signaling. Among these, the CD3 molecule is one of the most important. The CD3 molecule involves in TCR structural stability as well as T cell activation signaling. A TCR-CD3 complex is created when TCR and CD3 form a non-covalent bond. Antigen recognition and T cell signaling are both facilitated by the TCR-CD3 complex. When a CD3 subunit is absent, a TCR-CD3 complex cannot form, and none of the subunits is transported to the cell surface. Thus, T cells cannot develop. Consequently, research on the physiological functions and potential pathogenicity of CD3 subunits can clarify the pathogenesis of immune system diseases and can offer fresh approaches to the treatment of it. In this review, the structure and function of the TCR-CD3 complex in the immune system was summarized, the pathogenicity of each CD3 subunit and therapeutic approaches to related diseases was explored and research directions for the development of new targeted drugs was provided.

Safety and efficacy of targeting CD138 with a chimeric antigen receptor for the treatment of multiple myeloma

After unprecedented successes in B-cell malignancies, chimeric antigen receptor T cells have recently been investigated for the treatment of multiple myeloma. Chimeric antigen receptor targeting T cells B-cell maturation antigen (BCMA) on malignant plasma cells have led to impressive clinical responses in recent trials. However, BCMA-negative relapses have been observed, supporting the need for complementary treatment strategies. Here, we explored the feasibility of targeting CD138 (syndecan-1), a surface marker expressed on both normal and malignant plasma cells. We showed that T cells from both healthy donors and from multiple myeloma patients, when transduced with a CD138-specific chimeric antigen receptor, can eliminate tumor cell lines and primary myeloma cells both in vitro and in vivo. CD138 is also expressed by putative myeloma stem cells identified by Hoechst staining, and these cells can be eliminated by CD138-specific chimeric antigen receptor T cells. Preclinical analyses did not identify any on target off tumor cytotoxicity against normal epithelial or endothelial cells, further supporting the rationale for the use of adoptively transferred CD138-specific chimeric antigen receptor T cells for the treatment of patients with relapsed/refractory multiple myeloma.

Characterization of γδ regulatory T cells from peripheral blood in patients with multiple myeloma

γδ regulatory T cells are able to inhibit the activation and function of T cells involved in antigen-specific immune responses. This study aimed to investigate the potential role of γδ regulatory T cells in inhibiting anti-tumor immune responses in patients diagnosed as multiple myeloma (MM). We measured the levels of γδ T cells, the distribution and clonally amplified TCR Vγ and VδT cells in peripheral blood of healthy donors, patients recently diagnosed with MM, and MM patients in remission cohorts. In addition, we evaluated the ability of γδ regulatory T cells to inhibit the proliferation of CD4+CD25- T cells and detected the expression of immunoregulatory-associated molecules. We found that the levels of γδ regulatory T cells from the peripheral blood in patients of MM were significantly higher than those in healthy donors. Comparison of γδT regulatory cells function in MM and healthy donors showed similarly inhibitory effects on the proliferation of T cells. Additionally, TLR8 expression level increased significantly in MM patients compared to healthy donors, while the expression levels of Foxp3, CD25, CTLA4, GITR, GATA3 and Tbet in MM patients and healthy donors showed no significant difference. Taken together, our study reveals the potential role of γδ regulatory T cells in inhibiting anti-tumor immune responses in MM patients.

Molecular alterations in the TCR signaling pathway in patients with aplastic anemia

Background

A previous study has demonstrated a significantly increased CD3ζ gene expression level in aplastic anemia (AA). However, the mechanism underlying the upregulated CD3ζ mRNA expression level and that of T cell activation signaling molecules in AA patients remains unclear. Thus, we investigated the expression levels of the CD3ζ, CD28, CTLA-4, and Cbl-b genes, the SNP rs231775 in the CTLA-4 gene, and the distribution of the CD3ζ 3′-UTR splice variant in AA patients.

Methods

CD3ζ 3′-UTR splice variants were identified in peripheral blood mononuclear cells (PBMCs) from 48 healthy individuals and 67 patients with AA [37 cases of severe aplastic anemia (SAA) and 30 cases of non-sever aplastic anemia (NSAA)] by RT-PCR. CD3ζ, CD28, CTLA-4, and Cbl-b gene expression was analyzed by real-time quantitative PCR. The SNP rs231775 in CTLA-4 gene was analyzed by PCR-RFLP.

Results

CD3ζ and CD28 expression was significantly higher, while CTLA-4 and Cbl-b expression was significantly lower in AA patients compared with healthy individuals. Significantly higher CD3ζ expression was found in the NSAA subgroup compared with the SAA subgroup. 64 % of the AA samples had the same genotype (WT⁺AS⁺CD3ζ 3′-UTR); 22 % of the AA patients had a WT⁺AS⁻CD3ζ 3′-UTR genotype, and 14 % of the AA patients had a WT⁻AS⁺CD3ζ 3′-UTR genotype. The CD3ζ expression level of WT⁻AS⁺ subgroup was the highest in the SAA patients. A significantly higher frequency of the GG genotype (mutant type, homozygous) of SNP rs231775 in CTLA-4 gene was found in the AA patients. Positive correlation between the CTLA-4 and Cbl-b gene expression levels was found in healthy individuals with the AA and AG genotypes, but not in the AA patients.

Conclusions

This is the first study analyzing the expression characteristics of the CD28, CTLA-4, and Cbl-b genes in AA. Our results suggest that aberrant T cell activation may be related to the first and second signals of T cell activation in AA. The GG genotype of SNP rs231775 in CTLA-4 gene might be associated with AA risk in the Chinese population. The characteristics of CD3ζ 3′-UTR alternative splicing may be an index for evaluating the T cell activation status in AA patients, particularly in SAA patients.

Characteristics of TCRζ, ZAP-70, and FcɛRIγ gene expression in patients with T- and NK/T-cell lymphoma

Abnormal expression of key signaling molecules and defective T-cell function play a crucial role in the pathogenesis of T-cell immunodeficiency in hematological malignancies. To understand the molecular basis of T-cell signaling abnormalities and TCRζ chain deficiencies in T- and NK/T-cell lymphoma, the expression level of the TCRζ, ZAP-70, and FcɛRIγ genes in peripheral blood mononuclear cells from 25 patients with T-cell lymphoma, 16 patients with NK/T-cell lymphoma (NK/T-CL), and 26 healthy individuals was determined. In addition, their relationship with disease stage and TCRζ 3' untranslated region (3'UTR) splice variants was analyzed in this study. The expression level of all three genes was significantly altered with disease progression, and a decreasing trend was found in patients compared with healthy controls. TCRζ and ZAP-70 were significantly positively related in all samples, and a negative relationship between TCRζ and FcɛRIγ was significantly lost in NK/T-CL patients. Moreover, distinct expression patterns were defined for patient groups with different TCRζ 3'UTR isoforms. In conclusion, a lower expression pattern for all three genes may indicate a weaker immune status based on reduced TCRζ and ZAP-70 expression without the complementary effects of FcɛRIγ, while aberrant TCRζ 3'UTR splicing may contribute to T-cell receptor (TCR) signaling regulation in T cells from patients with T- and NK/T-cell lymphoma.

Altered expression pattern of miR-29a, miR-29b and the target genes in myeloid leukemia

Objectives

The miR-29 family have been demonstrated acting as vital tumor suppressor in multiple cancers as well as regulators in the adaptive immune system. Little is known about their role in leukemogenesis. The purpose of this study is to analyze the expression pattern of miR-29a/29b and its target genes Mcl-1 (myeloid cell leukemia sequence 1) and B-cell lymphoma 2 (Bcl-2) in myeloid leukemia.

Methods

Quantitative real-time PCR was used for detecting genes expression level in peripheral blood mononuclear cells (PBMCs) from 10 cases with newly diagnosed, untreated acute myeloid leukemia (AML) and 14 cases with newly diagnosed, untreated chronic myeloid leukemia (CML) in chronic phase, and 14 healthy individual (HI) served as controls. Correlation between the relative expression levels of different genes have been analyzed.

Results

Significant lower expression of miR-29a/29b and higher expression level of two potential target genes Bcl-2 and Mcl-1 were found in PBMCs from AML and CML patients compared with HI group. In addtion, miR-29a expression in AML was significantly lower than that in CML. Moreover, negative correlation between miR-29a/29b and its target genes have been found. While, positive correlation between relative expression level of miR-29a and miR-29b or Bcl-2 and Mcl-1 were presented in the total 38 research objects.

Conclusion

Down-regulated miR-29a and miR-29b, and accompanying up-regulated Bcl-2 and Mcl-1 are the common feature in myeloid leukemias. These data further support the role for miR-29a/29b dysregulation in myeloid leukemogenesis and the therapeutic promise of regulating miR-29a/29b expression for myeloid leukemia in the future.

Expression feature of CD3, FcεRIγ, and Zap-70 in patients with chronic lymphocytic leukemia

In leukemia patients, T-cell function has been suppressed with the disease progress. Patients with chronic lymphocytic leukemia (CLL) are all to a degree immunodeficient. In order to elucidate the feature of T-cell receptor signal transduction in CLL, the expression levels of CD3γ, δ, ε, and ζ chain, FcεRIγ, and Zap-70 genes in peripheral blood mononuclear cells (PBMCs) were analyzed. Real-time polymerase chain reaction with SYBR Green technique was used for detecting the gene expression level in PBMCs from 13 patients with CLL, 13 healthy individuals, and 10 B-cell acute lymphocytic leukemia (B-ALL) served as control. The β2-microglobulin gene was used as an endogenous reference. Relative mRNA expression level of genes was analyzed by using the 2(-ΔCt) × 100% method. Significant lower expression levels of CD3γ, ε, and ζ chain genes, as well as FcεRIγ gene were found in CLL samples. Moreover, there was lost the negative correlation of the expression levels between CD3ζ and FcεRIγ genes. The expression level of Zap-70 in CLL was lower than those from healthy controls, while higher than those from B-ALL group. There was no significant correlation between the expression levels of CD3ζ and Zap-70 genes neither in the healthy group nor in the CLL group. In conclusion, the results provide a global gene expression profile of CD3γ, δ, ε, and ζ chains, and the CD3ζ-related genes FcεRIγ and Zap-70 in CLL. Deficiency of these gene expression levels might represent the feature related to T-cell immunodeficiency. The study might contribute to better understand the cellular immune features in CLL patients.

T-cell receptor repertoire usage in hematologic malignancies

Over the last few years several studies have addressed the possible influence of different immune mechanisms on the evolution of hematologic malignancies. More specifically, a fundamental role of reactive T-cells has now been demonstrated in the pathogenesis of many of these disorders as well as in the typical immunological milieu observed after stem cell transplantation in patients affected by these malignancies. In this context the study of the T-cell receptor (TCR) repertoire performed by different techniques, such as for instance flow cytometry and spectratyping, has undoubtedly provided a fundamental contribution. More recently, these seminal observations have even opened new potential therapeutic avenues based on the employment of adoptive T-cells somehow engineered toward potential neoplastic targets. This review will run through the most relevant studies which have tried to dissect the TCR repertoire usage in patients with different hematologic malignancies, especially focusing on the possible pathogenetic and therapeutic implications.

Upregulated TCRζ enhances interleukin-2 production in T-cells from patients with CML

T-cell immunodeficiency is a common feature in patients with chronic myeloid leukemia (CML), and deficiency in CD3 levels was detected in T cells from these patients, which may represent a characteristic that is related to a lower T cell activation. In this study, we explored the possibility that forced TCRζ gene expression may upreg-u-late T cell receptor (TCR) signaling activation and reverse interleukin-2 (IL-2) production in T cells from patients with CML. A recombinant eukaryotic vector expressing TCRζ was transfected into T cells by nucleofection. Phosphorylated TCRζ, phosphorylated NF-κB, and the IL-2 level in TCRζ-transfected CD3+T cells that were activated with anti-CD3 and anti-CD28 antibodies were measured by Western blot and enzyme-linked immunosorbent assay (ELISA). Significantly increased TCRζ levels were found in TCRζ-transfected CD3+T cells. After CD3 and CD28 antibody stimulation, a significantly higher phosphorylated TCRζ chain level was demonstrated, and an increased IL-2 production in TCRζ-upregulated T cells was associated with the increased expression of the phosphorylated NF-κB. In conclusion, TCRζ gene transfection could restore TCRζ chain deficiency and enhance IL-2 production in T cells from patients with CML. It is possible that TCRζ chain reconstitution in leukemia-specific, clonally expanded T cells will effectively increase their activation of antileukemia cytotoxicity.

Mutations increased overexpression of Notch1 in T-cell acute lymphoblastic leukemia

Background

The Notch signaling pathway is crucial in T-cell development, Notch1 mutations are frequently present in T-cell acute lymphoblastic leukemia (T-ALL). To investigate the feature of Notch1 mutation and its corresponding expression level in Chinese patients with T-ALL, detection of mutation and the expression level of Notch1 gene was preformed using RT-PCR, sequencing and real-time PCR respectively.

Results

Two Notch1 point mutations (V1578E and L1593P) located on HD-N domain were identified in three cases out of 13 T-ALL patients. The mutation on 4733 position (V1578E) found in two cases was a novel mutation. The overexpression of Notch1 was detected in all samples with T-ALL, moreover, significantly higher expression of Notch1 was detected in the T-ALL with Notch1 mutation group compared with T-ALL with WT Notch1 group (p = 0.0192).

Conclusions

Higher expression of Notch1 was associated with Notch1 mutation, more novel mutation of this gene might be identified in different populations and its contribution to the molecular pathogenesis of T-ALL is needed further research.

Chemokine-dependent B cell-T cell interactions in chronic lymphocytic leukemia and multiple myeloma - targets for therapeutic intervention?

INTRODUCTION

Chemokines and their receptors play essential roles in the development, maintenance and proper functioning of the immune system. B cell-T cell interactions are modulated by chemokines. In B cell malignancies, these interactions may have tumor-promoting consequences.

AREAS COVERED

This review summarizes physiological B cell-T cell interactions and discusses their pathological role in the onset and progression of B cell malignancies with a special focus on chronic lymphocytic leukemia and multiple myeloma. Experimental data on chemokine-guided B cell-T cell actions in B cell malignancies from murine models as well as in vitro data are summarized and their potential as future therapeutic targets is critically discussed.

EXPERT OPINION

Direct or indirect targeting of chemokine receptors involved in localization and T-cell-dependent activation of B lymphocytes can provide strong synergisms with conventional or immunomodulatory therapies by disrupting the microenvironmental conditions necessary for survival and proliferation of malignant B lymphocytes. However, further knowledge of these interactions between B and T cells is needed.

A change in CD3γ, CD3δ, CD3ϵ, and CD3ζ gene expression in T-lymphocytes from benzene-exposed and benzene-poisoned workers

Benzene is known to be highly toxic to a variety of cell types, including lymphocytes. A previous study showed that T-lymphocyte immune function disorder might be related to benzene exposure. To elucidate characteristics of TCR signal transduction in benzene-exposed workers, expression levels of CD3γ, CD3δ, CD3ϵ, and CD3ζ genes in peripheral blood mononuclear cells (PBMC) were analyzed. Real-time RT-PCR using SYBR Green I was used to detect CD3 gene expression levels in PBMC from 20 benzene-exposed workers, seven workers with chronic mild benzene poisoning, five workers with chronic severe benzene poisoning and 14 healthy individuals (controls). The relative mRNA expression level was analyzed by the 2(-Δct) × 100% method. In benzene-exposed worker cells, significantly higher CD3δ, CD3ϵ, and CD3ζ, expression levels were observed as compared with values for cells from the healthy controls. In the workers with chronic severe benzene poisoning, lymphocyte CD3γ, CD3ϵ, and CD3ζ gene expression levels were significantly lower than in control cells. Lymphocytes from chronic mildly benzene- poisoned workers evinced two different gene expression patterns, i.e., CD3γ and CD3ϵ levels were similar to those in the benzene-exposed worker cells, but CD3δ and CD3ζ expression levels were significantly lower relative to those in cells from chronic severely-benzene-poisoned counterparts. It remained to be determined if these reductions in expression of these genes presage or are indicative of deficiencies in the activities of T-lymphocytes in these workers. For now, it is hoped that this study may contribute to a better understanding of the disorders in cellular immunity frequently found with benzene-exposed workers.