Distribution of T-cell signalling molecules in human myeloma

Development of a B-cell maturation antigen-specific T-cell antigen coupler receptor for multiple myeloma

BACKGROUND AIMS

T cells engineered with synthetic receptors have delivered powerful therapeutic results for patients with relapsed/refractory hematologic malignancies. The authors have recently described the T-cell antigen coupler (TAC) receptor, which co-opts the endogenous T-cell receptor (TCR) and activates engineered T cells in an HLA-independent manner. Here the authors describe the evolution of a next-generation TAC receptor with a focus on developing a TAC-engineered T cell for multiple myeloma.

METHODS

To optimize the TAC scaffold, the authors employed a bona fide antigen-binding domain derived from the B-cell maturation antigen-specific monoclonal antibody C11D5.3, which has been used successfully in the clinic. The authors first tested humanized versions of the UCHT1 domain, which is used by the TAC to co-opt the TCR. The authors further discovered that the signal peptide affected surface expression of the TAC receptor. Higher density of the TAC receptor enhanced target binding in vitro, which translated into higher levels of Lck at the immunological synapse and stronger proliferation when only receptor-ligand interactions were present.

RESULTS

The authors observed that the humanized UCHT1 improved surface expression and in vivo efficacy. Using TAC T cells derived from both healthy donors and multiple myeloma patients, the authors determined that despite the influence of receptor density on early activation events and effector function, receptor density did not impact late effector functions in vitro, nor did the receptor density affect in vivo efficacy.

CONCLUSIONS

The modifications to the TAC scaffold described herein represent an important step in the evolution of this technology, which tolerates a range of expression levels without impacting therapeutic efficacy.

Primarily screening and analyzing ESTs differentially expressed in rats' primary liver cancer

OBJECTIVE

To screen and analyze key express sequence tags (ESTs) which were differentially displayed in every period of SD rats' primary hepatic carcinoma and reveal the molecular mechanism of carcinogenesis.

METHODS

Using diethylnitrosamine (DENA) as a cancerigenic agent, animal models with different phases of primary hepatic cancer were constructed in SD rats. Rats were respectively sacrificed at d 14, d 28, d 56, d 77, d 105 and d 112 after the rats received DENA by gavage, then the livers were harvested. One part of the livers was classified according to their pathological changes, while the other was reserved for molecular mechanism studies on hepatocarcinogenesis. The differentially expressed genes were isolated from both normal and morbid tissues by mRNA differential display technique (DDRT-PCR). After the fragments were sequenced, bioinformatics were used to analyze the results.

RESULTS

Twelve differentially expressed cDNA fragments were obtained. Nine fragments had the homology with known cDNA clones, especially EST-7 was similar to BN/SsNHsdMCW mitochondrion gene and the identity was 100% which suggested EST-7 may be the part of BN/SsNHsdMCW mitochondrion gene. In contrast, other three fragments (EST-1, EST-3 and EST-5) had extremely low identity to any genes registered in GENBANK databases.

CONCLUSIONS

BN/SsNHsdMCW mitochondrion gene was expressed in different periods of hepatocarcinogenesis. Moreover, EST-1, EST-3 and EST-5 were suggested to contribute to the development of rat hepatocarcinogenesis, and thus may be candidates of new targets of oncogenes or cancer suppressor genes.

Variations in suppressor molecule ctla-4 gene are related to susceptibility to multiple myeloma in a polish population

Various phenotype and functional T-cell abnormalities are observed in multiple myeloma (MM) patients. The aim of this study was to investigate the association between polymorphisms in the gene encoding cytotoxic T-lymphocyte antigen-4 (CTLA-4), a negative regulator of the T-lymphocyte immune response and susceptibility to multiple myeloma in a Polish population. Two hundred MM patients and 380 healthy subjects were genotyped for the following polymorphisms: CTLA-4c.49A>G, CTLA-4g.319C>T, CTLA-4g.*642AT(8_33), CT60 (CTLA-4g.*6230G>A), Jo31 (CTLA-4g.*10223G>T). Our study is the largest and most comprehensive evaluation to date of the association between genetic polymorphisms in the CTLA-4 molecule and multiple myeloma. It was found that CTLA-4c.49A>G[G], CT60[G], and Jo31[G] alleles were more frequently observed in MM patients than in controls (0.50 vs. 0.44, p = 0.03, 0.65 vs. 0.58, p = 0.04, and 0.63 vs. 0.57, p = 0.03, respectively). Moreover, the haplotype CTLA-4c.49A>G[G], CTLA-4g.319C>T[C], CTLA-4g.*642AT(8_33) [8], CT60[G], Jo31[G] including all susceptibility alleles increases the risk of MM about fourfold (OR: 3.79, 95%CI: 2.08–6.89, p = 0.00001). These findings indicate that genetic variations in the CTLA-4 gene play role in susceptibility to multiple myeloma and warrant further investigation through replication studies.

Immunomodulatory effects of lenalidomide and pomalidomide on interaction of tumor and bone marrow accessory cells in multiple myeloma

The bone marrow (BM) microenvironment consists of extracellular-matrix and the cellular compartment including immune cells. Multiple myeloma (MM) cell and BM accessory cell interaction promotes MM survival via both cell-cell contact and cytokines. Immunomodulatory agents (IMiDs) target not only MM cells, but also MM cell-immune cell interactions and cytokine signaling. Here we examined the in vitro effects of IMiDs on cytokine signaling triggered by interaction of effector cells with MM cells and BM stroma cells. IMiDs diminished interleukin-2, interferonγ, and IL-6 regulator suppressor of cytokine signaling (SOCS)1 expression in immune (CD4T, CD8T, natural-killer T, natural-killer) cells from both BM and PB of MM patients. In addition, coculture of MM cells with healthy PBMCs induced SOCS1 expression in effector cells; conversely, treatment with IMiDs down-regulated the SOCS1 expression. SOCS1 negatively regulates IL-6 signaling and is silenced by hypermethylation in MM cells. To define the mechanism of inhibitory-cytokine signaling in effector cells and MM cells, we next analyzed the interaction of immune cells with MM cells that were epigenetically modified to re-express SOCS1; IMiDs induced more potent CTL responses against SOCS1 re-expressing-MM cells than unmodified MM cells. These data therefore demonstrate that modulation of SOCS1 may enhance immune response and efficacy of IMiDs in MM.

Immunodeficiency and immunotherapy in multiple myeloma

Multiple myeloma is a malignant tumour of plasma cells that remains incurable for the vast majority of patients, with a median survival of 2-3 years. It is characterized by the patchy accumulation of tumour cells within bone marrow leading to variable anaemia, bone destruction, hypercalcaemia, renal failure and infections. Immune dysfunction is an important feature of the disease and leads to infections that are both a major cause of morbidity and mortality and may promote tumour growth and resistance to chemotherapy. Numerous defects of the immune system have been described in multiple myeloma although the relative clinical importance of these remains elusive. There has been considerable interest in the identification of an autologous response against myeloma. Although T cells and humoral responses directed against myeloma-associated antigens have been described, it is uncertain if the immune system plays a role in preventing or controlling myeloma cell growth. There is increasing interest in the potential role of immunotherapy but the success of these interventions is likely to be modified by the immunologically hostile environment associated with multiple myeloma. This review attempts to summarize the current knowledge relating to the immune defects found in multiple myeloma.

The role of protein kinase C-alpha in hematologic malignancies

In recent years advances in histopathological and molecular understanding of hematologic malignancies have led to the development of drugs which selectively target proteins associated with hematologic tumorigenesis. One such targeted agent is the antisense oligonucleotide aprinocarsen, which specifically inhibits the signaling protein, protein kinase C-alpha (PKC-alpha). Although PKC-alpha has been associated with tumorigenesis, its role and expression levels in patients with hematologic malignancies are not well understood. We here review studies investigating the expression and role of PKC-alpha in hematologic malignancies. Such a review may offer new insights on how to develop strategies in identifying patients that might best benefit from PKC-alpha inhibition.

Effector gammadelta T cells and tumor cells as immune targets of zoledronic acid in multiple myeloma

The aim of this study was to investigate the in vitro immunomodulatory effects of zoledronic acid (Zol) on peripheral blood Vgamma9/Vdelta2 (gammadelta) T cells of normal donors and multiple myeloma (MM) patients. gammadelta T cells were stimulated with Zol and low doses of interleukin-2 (IL-2), and then analyzed for proliferation, cytokine production, and generation of effector activity against myeloma cell lines and primary myeloma cells. Proliferation of gammadelta T cells was observed in 100% of normal donors and 50% of MM patients. gammadelta T cells produced IFN-gamma, surface mobilized the CD107a and CD107b antigens, and exerted direct cell-to-cell antimyeloma activity irrespective of the ability to proliferate to Zol and IL-2. The memory phenotype was predominant in the MM gammadelta T cells that proliferated in response to Zol (responders), whereas effector cells were predominant in those that did not (nonresponders). Zol induced antimyeloma activity through the monocyte-dependent activation of gammadelta T cells and by enhancing the immunosensitivity of myeloma cells to gammadelta T cells. Mevastatin, a specific inhibitor of hydroxy-methylglutaryl-CoA reductase, completely abrogated this antimyeloma activity.

Signalling molecules and cytokine production in T cells of multiple myeloma-increased abnormalities with advancing stage

T-cell immune dysfunction in patients with malignant tumours has been attributed to the altered expression of components of the T-cell receptor (TCR)/CD3 complex and their associated intracellular protein tyrosine kinases. In this study, four-colour flow cytometry was applied to study the surface bound molecules TCRalphabeta, CD28, CD152 and CD154 involved in T-cell signalling and the signal transduction molecules CD3zeta, p56lck, p59fyn, ZAP-70 and phosphatidyl-inositol-3 kinase (PI3-k) as well as the intracellular cytokines interferon-gamma (IFN-gamma), interleukin (IL)-4 and IL-2 as a functional read-out of non-stimulated and superantigen (staphylococcus enterotoxin B)-stimulated blood T cells of multiple myeloma (MM) patients at different stages of the disease. Multiple abnormalities were demonstrated in the CD4 and CD8 populations, both under non-stimulated and superantigen-stimulated conditions. There was a marked reduction, particular in advanced stage MM, in the proportion of CD4 and CD8 cells expressing CD28, CD152, CD3zeta, p56lck, ZAP-70 and PI3-k. The level of intracellular T-cell cytokines (IFN-gamma, IL-2 and IL-4) was normal or increased in non-stimulated cells but activation-induced cytokine production was impaired. These results illustrated profound and multiple T-cell signalling defects, from the surface and down-stream, consistent with involvement of a master T-cell function, especially in advanced stage MM. These data should be taken into consideration when developing immune-based therapeutic approaches and when applying new emerging technologies that aim to restore T-cell functions.

Viral antigen-specific CD8+ T-cell responses are impaired in multiple myeloma

Multiple myeloma (MM) is associated with defects of humoral and cellular immunity, however, little is known about the frequency and function of antigen-specific CD8+ T cells. Such information might be critical for the development of immunotherapy for MM patients. As a model, we assessed the frequency and proliferation of CD8+ T cells specific for HLA-A*0201-restricted immunodominant epitopes from influenza A (Inf A) and Epstein-Barr virus (EBV). Experiments in identical twins demonstrated reduced numbers of antigen-specific T cells after ex-vivo antigenic challenge in the MM twin when compared with the healthy twin. Similarly, the proliferation and frequency of EBV- and Inf A-specific T cells was also significantly reduced in a cohort of 24 previously untreated or conventionally treated MM patients when compared with 19 healthy individuals. In contrast, MM patients studied after receiving an autologous stem cell transplantation showed strikingly higher frequencies of EBV-specific T cells with potential to proliferate ex vivo, suggesting that EBV-specific T cells are readily expandable under these circumstances. These data identify an impaired response of CD8+ T cells in MM patients, which might in part explain the relatively limited success of anti-MM immunisations. Prospective studies will determine whether such immune assessment strategies may identify patients more likely to benefit from cancer immunotherapy.

No alteration in NK function or zeta chain expression in NK and T cells of cervical cancer patients

OBJECTIVE

To investigate in vitro natural killer (NK) cell activity and expression of signal-transducing zeta chains in patients with cervical cancer.

PATIENTS AND METHODS

Experiments were performed with frozen lymphocytes from patients at all disease stages and from healthy controls. Thawed NK were activated by overnight incubation in interferon-gamma (IFN-gamma); activity against two target cell lines was assessed by 4-h (51)Cr release assay. Targets chosen were K562, an erythroleukemic cell line, and a cervical carcinoma cell line designated 808. T and NK cell zeta chain expression was measured by flow cytometry.

RESULTS

Patients' NK were found to be as cytotoxic as those of normal controls against cell lines K562 and 808. Patient T and NK cells did not show significant down-regulation of the zeta chain.

CONCLUSIONS

We have found no evidence to suggest that loss of zeta chains is a mechanism for immunocompromise in patients with cervical carcinoma. IFN-recoverable patient NK activity is not reduced compared to matched controls. This may be clinically relevant since NK are active against cells exhibiting class I human leukocyte antigen (HLA) down-regulation and many cervical cancers show loss of HLA.

Determination of plasma cell secreting potential as an index of maturity of myelomatous cells and a strong prognostic factor

According to the widely accepted myeloma staging system, the bulk of paraprotein is the main determinant of disease stage. However, myelomatous plasma cells differ considerably in their ability to synthesize and secrete monoclonal paraprotein. We determined plasma cell secreting potential (PCSP) as the amount of M-component, divided by the percentage of marrow plasmacytic infiltration, in 240 patients with myeloma, and correlated our results with chain isotype, plasma cell morphology, severity of bone disease, well-recognized prognostic factors, such as serum LDH, CRP, albumin and beta2-microglobulin, treatment response and overall survival. PCSP was higher in IgG than in other myeloma types, and was an almost constant parameter for each individual patient, in 134/166 cases. A > 10% decrease of PCSP in 26 patients was associated with disease aggressiveness and treatment failure. Patients with MGUS had significantly higher PCSP than those with myeloma of the same chain type. Higher PCSP was associated with stage I, absence of Bence-Jones proteinuria and indolent forms of disease with lower proliferating cell nuclear antigen (PCNA) positivity, serum LDH, alpha2-globulins, CRP and beta2-microglobulin and higher albumin levels. Conversely, patients with immature/plasmablastic morphology and those with severe bone disease had lower PCSP. Good responders to treatment had significantly higher PCSP than moderate and poor responders and PCSP was strongly correlated with overall survival in IgG and IgA myeloma. In conclusion, PCSP reflects the maturation status of myelomatous cells and therefore can be used as a prognostic factor, since patients with high secreting potential represent a lower malignancy group, in comparison to those with a low secreting potential.

Low serum levels of CD44, CD44v6, and neopterin indicate immune dysfunction in chronic pancreatitis

INTRODUCTION

In autoimmune diseases, malignancies, and inflammatory conditions, a correlation of serum levels of CD44, interleukin-2 receptor (IL-2r), and neopterin with disease activity could be shown.

AIMS

To assess the immune parameters in chronic pancreatitis in correlation to clinical data to evaluate the potential role of immune dysfunction as a risk factor.

METHODOLOGY

Levels of IL-2r, sCD44, sCD44v6, and neopterin were measured using the enzyme-linked immunosorbent assay in 63 patients with chronic pancreatitis who underwent surgery between 1992 and 1995 in our institution. Clinical data were evaluated prospectively before surgery, and a follow-up investigation was conducted in 1997.

RESULTS

Mean serum levels of CD44, CD44v6, and neopterin were significantly lower in patients with chronic pancreatitis compared with the control group. The mean level of IL-2r was also lower in chronic pancreatitis, but this difference was not significant. However, no influence of immunosuppressive factors such as alcohol consumption, cigarette smoking, or diabetes could be detected on the levels of IL-2r, CD44, CD44v6, and neopterin.

CONCLUSION

In accordance with other diseases of reduced immunoreactivity, depressed serum levels of biomarkers in chronic pancreatitis are caused by reduced T-lymphocyte and macrophage activation. By ruling out a significant influence of concomitant immunosuppressive factors, we conclude that the inflammatory process itself is the source of the depressed immune function, which might be restored by surgical resection.

Increased expression of non-functional killer inhibitory receptor CD94 in CD8+ cells of myeloma patients

Different MHC class I-specific killer inhibitory receptors (KIRs) are expressed in vivo by a minor fraction of activated memory CD8+ cells. It has been postulated that KIRs may 'fine-tune' specific responses by altering their threshold of activation by the TCR-CD3 complex. We have previously shown that, in multiple myeloma (MM) patients, a large fraction of peripheral blood CD8+ cells display the phenotype of chronically activated memory T cells (CD38+, HLA-DR+, CD25-, CD45R0+, CD28-). We investigated the expression of KIRs on MM T cells and determined their possible influence on cytolytic responses elicited via the CD3-TCR complex. The expression of CD94, a molecule that is part of a heterodimeric KIR recognizing the non-classical MHC surface HLA-E molecule, was almost threefold higher in MM T cells than in age-matched normal control subjects (P < 0.0001). CD94 expression was preferentially confined to CD8+ cells but not restricted to activated (HLA-DR+) and/or memory (CD45R0+) T cells. Unlike normal T cells, in which CD94 is assembled with glycoproteins of the NKG2 family to form functional receptors with activating or inhibitory properties, most CD94+ MM T cells were devoid of both the NKG2-A and NKG2-C glycoproteins detected in the inhibitory or activating form respectively. CD94 blockade did not significantly affect either T-cell proliferation or cytotoxic T-lymphocyte generation induced by the myeloma-derived cell lines NCI and RPMI 8226. Similarly, the cytolytic activity induced by direct anti-CD3-mediated targeting of MM T cells to FCR+ P815 target cells was unaffected by the addition of anti-CD94 and/or anti-NKG2-A/C monoclonal antibodies (mAbs). These data indicate that the large majority of MM CD8+ cells do not express a functional CD94 receptor. Thus, their ability to 'fine-tune' an appropriate immune response against tumour cells can be impaired.

Expression of signal-transducing zeta chain in peripheral blood T cells and natural killer cells in patients with Hodgkin's disease in different phases of the disease

A number of phenotypic and functional alterations have been described in T cells of cancer patients. These changes are believed to reflect an impaired T-cell mediated immunity, which in turn, may result in a decreased capacity to generate an effective antitumor response. Several mechanisms have been proposed to explain depressed immunity in cancer patients including tumor-derived suppressor factors, abnormal cytokine production, deletion or inactivation of tumor-reactive T-cells. To investigate the mechanism underlying the immunodeficiency in Hodgkin's disease (HD) we studied the expression of T cell receptor zeta chain, which plays a vital role in the cascade of events leading to T and NK cell activation. The expression of the zeta chain of the T cell receptor/CD3 complex was analyzed by dual colour immunofluorescence on peripheral blood T lymphocytes: CD3+, CD4+, CD8+ and NK-cells (CD56+) in patients in different phases of the disease. Zeta chain was significantly reduced on CD3, CD4, CD8, and CD56 positive cells from patients in active phase of the disease compared with normal controls (p=0.05). In patients tested in complete clinical remission the values were normal except for the subpopulation of CD8+ cells in which the expression of zeta chain remained significantly reduced compared with controls. Downregulation of CD3/zeta-chain in PBLs and NK cells in active phase of HD- and to a lesser extent in clinical remission may contribute to immunodeficiency associated with the disease.

Immune regulation in multiple myeloma: the host-tumour conflict

Multiple myeloma (MM) remains essentially incurable by conventional anti-tumour therapy. This has led to increased interest in the possibility that forms of immune therapy might be effective. The successful use of donor lymphocyte infusions (DLI) in a few cases of MM relapse following allogeneic bone marrow transplantation have added weight to this view. MM is characterized by several defects in the host's immune system. The influence of the malignant clone on the function of the immune effector cells results from both passive and active suppression. Despite an array of functional adhesion molecules and HLA class I and II molecules on their surface and the secretion of a tumour-specific peptide, they fail to express adequate levels of co-stimulatory molecules thus inducing anergy in potentially tumour-specific T cells. In addition to this passive evasion of immune regulation, MM tumour cells are capable of producing a number of immunologically active agents which can induce immunosuppression such as transforming growth factor-beta, Fas ligand (FasL), vascular endothelial growth factor and Muc-1. It is postulated that these agents may be produced by the tumour cell to influence the microenvironment to support growth and differentiation of the clone but may have the additional benefit of altering the function of the host immune effector cells and thus preventing tumour rejection. This duality of function is important if clinicians are to design immunotherapy strategies which will achieve the true potential and result in improved survival in MM.