Drug-mediated and cellular immunotherapy in multiple myeloma

Circ_0005615 contributes to the progression and Bortezomib resistance of multiple myeloma by sponging miR-185-5p and upregulating IRF4

Circular RNAs (circRNAs) have been shown to play critical regulatory roles in multiple myeloma progression. Here, we aimed to explore the biologic role of circ_0005615 in multiple myeloma progression and its associated mechanism. Cell counting kit-8 assay was conducted to analyze the bortezomib resistance and proliferation of multiple myeloma cells. Cell proliferation was also analyzed by 5-Ethynyl-2'-deoxyuridine incorporation and flow cytometry assays. Cell apoptosis was assessed by flow cytometry. The interaction between microRNA-185-5p (miR-185-5p) and circ_0005615 or interferon regulatory factor 4 (IRF4) was verified by the dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. A xenograft tumor model was established in non-obese diabetic/server combined immune-deficiency mice to analyze the roles of circ_0005615 in tumor growth and bortezomib resistance. Circ_0005615 was upregulated in multiple myeloma tissues and cell lines. Circ_0005615 knockdown restrained the bortezomib resistance and proliferation and induced the apoptosis of multiple myeloma cells. Circ_0005615 acted as a molecular sponge for miR-185-5p, and the antitumor effects mediated by circ_0005615 knockdown were reversed by silencing miR-185-5p. IRF4 was confirmed as a direct target of miR-185-5p, and miR-185-5p overexpression-induced antitumor influences could be counteracted by IRF4 overexpression. Circ_0005615 could positively regulate IRF4 expression by sponging miR-185-5p in multiple myeloma cells. Circ_0005615 knockdown suppressed the growth and bortezomib resistance of xenograft tumors in vivo. Circ_0005615 contributed to the malignant progression and bortezomib resistance of multiple myeloma through mediating miR-185-5p/IRF4 signaling.

Potential Relationship between Clinical Significance and Serum Exosomal miRNAs in Patients with Multiple Myeloma

This study evaluated the potential relationship between exosomal miRNAs and clinical symptoms in patients with multiple myeloma (MM). Forty-eight newly diagnosed myeloma patients and sixteen normal donors were enrolled in the study. The results showed that the relative expression levels of let-7c-5p, let-7d-5p, miR-140-3p, miR-185-5p, and miR-425-5p in the exosomes of MM patients were significantly lower than those of healthy controls. Furthermore, there were significant differences in the clinical characteristics of myeloma, such as kidney damage, while the expression levels of the same miRNA in exosomes and serum are not correlated. The expression of exosomal miRNA is related to the expression levels of clinical feature-related factors, such as creatinine, β2-microglobulin, β-CTX, and IL-6 in serum. Establishing this relationship could contribute to understanding the pathogenesis of MM.

Immunotherapeutics in Multiple Myeloma: How Can Translational Mouse Models Help?

Multiple myeloma (MM) is usually diagnosed in older adults at the time of immunosenescence, a collection of age-related changes in the immune system that contribute to increased susceptibility to infection and cancer. The MM tumor microenvironment and cumulative chemotherapies also add to defects in immunity over the course of disease. In this review we discuss how mouse models have furthered our understanding of the immune defects caused by MM and enabled immunotherapeutics to progress to clinical trials, but also question the validity of using immunodeficient models for these purposes. Immunocompetent models, in particular the 5T series and Vk^⁎MYC models, are increasingly being utilized in preclinical studies and are adding to our knowledge of not only the adaptive immune system but also how the innate system might be enhanced in anti-MM activity. Finally we discuss the concept of immune profiling to target patients who might benefit the most from immunotherapeutics, and the use of humanized mice and 3D culture systems for personalized medicine.

Spontaneous onset and transplant models of the Vk*MYC mouse show immunological sequelae comparable to human multiple myeloma

Background

The Vk*MYC transgenic and transplant mouse models of multiple myeloma (MM) are well established as a research tool for anti-myeloma drug discovery. However, little is known of the immune response in these models. Understanding the immunological relevance of these models is of increasing importance as immunotherapeutic drugs are developed against MM.

Methods

We set out to examine how cellular immunity is affected in Vk*MYC mouse models and compare that to the immunology of patients with newly diagnosed and relapsed/refractory MM.

Results

We found that there were significant immunological responses in mice developing either spontaneous (transgenic) or transplanted MM as a consequence of the degree of tumor burden. Particularly striking were the profound B cell lymphopenia and the expansion of CD8⁺ effector memory T cells within the lymphocyte population that progressively developed with advancing disease burden, mirroring changes seen in human MM. High disease burden was also associated with increased inflammatory cytokine production by T lymphocytes, which is more fitting with relapsed/refractory MM in humans.

Conclusions

These findings have important implications for the application of this mouse model in the development of MM immunotherapies.

Trial registration LitVacc ANZCTR trial ID ACTRN12613000344796; RevLite ANZCTR trial ID NCT00482261

MiR-15a/16 regulates the growth of myeloma cells, angiogenesis and antitumor immunity by inhibiting Bcl-2, VEGF-A and IL-17 expression in multiple myeloma

miRNAs have been reported to be involved in the pathogenesis of many cancers. In this article, we investigated the role and the mechanisms of miR-15a/16 in the pathogenesis of multiple myeloma (MM). We found that miR-15a/16 was down-regulated in bone marrow-derived mononuclear cells (BM-MNCs) of newly diagnosed patients with MM and the downregulation of miR-15a/16 was correlated with International Staging System (ISS) stage. We then demonstrated miR-15a/16 inhibited myeloma cells proliferation, and increased apoptosis rate of U266 cells by suppressing the expression of anti-apoptosis protein Bcl-2. We also found miR-15a/16 could decrease VEGF-A and IL-17 levels in the supernatant of myeloma cells. These results indicate that miR-15a/16 may function as a tumor suppressor in MM through multiple regulatory mechanisms and they may be potential targets for the therapy of MM.

[Potential relationship and clinical significance of miRNAs and Th17 related cytokines in patients with multiple myeloma]

目的

探讨miRNA和Th17相关细胞因子在多发性骨髓瘤(MM)患者发病中的作用机制。

方法

收集27例MM患者骨髓标本，以8名健康人为正常对照，应用荧光实时定量PCR(qRT-PCR)法检测其miR-15a/16、-34a、-194-2-192簇、-181a/b的表达情况，采用ELISA法检测患者血清Th17相关细胞因子IL-17、IL-21、IL-22、IL-23、IL-27的表达水平。分析miRNA与Th17相关细胞因子表达的相关性。

结果

与对照组比较，MM患者组miR-15a/16、-34a、-194-2-192簇表达水平降低，而miR-181a/b表达水平升高，差异均有统计学意义（P值均<0.05）；MM患者血清IL-17、IL-21、IL-27的表达水平升高，IL-22表达水平降低，差异均有统计学意义（P值均<0.05）；IL-23表达水平与对照组相比差异无统计学意义（P>0.05)。ISS分期Ⅲ期患者的miR-181a/b和IL-17、IL-21、IL-23、IL-27表达水平高于Ⅰ期患者，而miR-15a/16、-34a、-194和IL-22的表达水平则低于后者，差异均有统计学意义（P值均< 0.05）。miR-34a与IL-21，miR-181a与IL-23，miR-192与IL-21、IL-27，miR-194与IL-27的表达水平均呈正相关，而miR-192与IL-21呈负相关（P值均<0.05）。

结论

miRNA和Th17相关细胞因子在MM患者中均存在异常表达，其表达水平与MM患者的ISS分期有关，同时两者之间也存在密切的联系，提示失调的miRNA可能影响Th17细胞的分化进而参与MM的发生、发展。

Potential relationship and clinical significance of miRNAs and Th17 cytokines in patients with multiple myeloma

We evaluated the potential relationship between miRNAs and Th17 cytokines in multiple myeloma (MM) patients. Twenty-seven newly diagnosed myeloma patients and eight normal donors were studied. We determined that the relative expression levels of miR-15a/16, miR-34a, miR-194 in MM patients were significantly lower than those in the healthy controls with exception for miR-181a/b, which showed significantly higher in MM patients (P<0.05). In contrast, the levels of IL-17, IL-21 and IL-27 were up-regulated in MM patients compared to healthy controls while IL-22 was down-regulated (P<0.05). The expression patterns of them were differentially present in various groups according to the International Staging System (ISS) criteria. Up-regulated IL-17, IL-21 and IL-27 may potentially down-regulate the expression of several miRNAs in MM patients. Establishment of the relationship may be useful for understanding the pathogenesis of MM and for clinical diagnosis of the disease.

Modulation of natural killer cell effector functions through lenalidomide/dasatinib and their combined effects against multiple myeloma cells

The multikinase inhibitor dasatinib blocks the constitutive activation of oncogenic Src kinases in multiple myeloma (MM) cells and potentially enhances natural killer (NK) cell activity. Therefore, we tested combination effects of dasatinib and lenalidomide regarding MM cell viability and NK cell effector functions. The drug combination mostly had little influence on the viability of MM cell lines, and produced mixed results on primary MM cells. Prolonged lenalidomide treatment enhanced NK cell effector functions, and dasatinib addition at late stages of NK cell expansion increased levels of CD107a/b and interferon-γ (IFNγ), but not of tumor necrosis factor-α (TNFα). Additive effects were observed for the enhancement of cytokine production and degranulation, but only lenalidomide increased NK cell cytotoxicity against MM cells. This effect correlated with increased TNF-related apoptosis-inducing ligand (TRAIL) expression and was attenuated by dasatinib, or suppressors of TRAIL or TNFα. Our data thus indicate a functional role for the TRAIL/TRAIL-R system in lenalidomide-mediated NK-cell activity against MM cells, but also show that dasatinib is unsuitable to support or boost this effect.

New rising infection: human herpesvirus 6 is frequent in myeloma patients undergoing autologous stem cell transplantation after induction therapy with bortezomib

Herpesvirus 6 (HHV-6) infection is a common complication during immunosuppression. Its significance for multiple myeloma (MM) patients undergoing autologous stem cell transplantation (ASCT) after treatment with novel agents affecting immune system remains undetermined. Data on 62 consecutive MM patients receiving bortezomib-dexamethasone (VD) (n = 41; 66%) or thalidomide-dexamethasone (TD) (n = 21, 34%) induction, together with melphalan 200 mg/m² autograft between 01.2005 and 09.2010, were reviewed. HHV-6 reactivation was diagnosed in patients experiencing postengraftment unexplained fever (PEUF) in the presence of any level of HHHV-6 DNA in blood. There were no statistically significant differences in patient characteristics between the groups, excluding dexamethasone dosage, which was significantly higher in patients receiving TD. Eight patients in TD and 18 in VD cohorts underwent viral screening for PEUF. HHV-6 reactivation was diagnosed in 10 patients of the entire series (16%), accounting for 35% of those screened; its incidence was 19.5% (n = 8) in the VD group versus 9.5% (n = 2) in the TD group. All patients recovered without sequelae. In conclusion, HHV-6 reactivation is relatively common after ASCT, accounting for at least a third of PEUF episodes. Further studies are warranted to investigate whether bortezomib has an impact on HHV-6 reactivation development.

Safrole-modulated immune response is mediated through enhancing the CD11b surface marker and stimulating the phagocytosis by macrophages in BALB/c mice

Safrole, a component of piper betle inflorescence, is a documented rodent hepatocarcinogen and inhibits bactericidal activity and the release of superoxide anion (O(2-)) by polymorphonuclear leukocytes (PMNs). In the present study, we investigated the effects of safrole on immune responses, including natural killer (NK) cell cytotoxicity, phagocytic activity and population distribution of leukocytes from normal BALB/c mice. The cells population (cell surface markers) and phagocytosis by macrophages and monocytes from the peripheral blood mononuclear cells (PBMCs) were determined, and NK cell cytotoxicity from splenocytes of mice after oral treatment with safrole was performed using flow cytometric assay. Results indicated that safrole did not affect the weights of body, spleen and liver when compared with the normal mice group. Safrole also promoted the levels of CD11b (monocytes) and Mac-3 (macrophages) that might be the reason for promoting the activity of phagocytosis. However, safrole reduced the cell population such as CD3 (T cells) and CD19 (B cells) of safrole-treated normal mice by oral administration. Furthermore, safrole elevated the uptake of Escherichia coli-labelled fluorescein isothiocyanate (FITC) by macrophages from blood and significantly stimulated the NK cell cytotoxicity in normal mice in vivo. In conclusions, alterations of the cell population (the increase in monocytes and macrophages, respectively) in safrole-treated normal BALB/c mice might indirectly influence the immune responses in vivo.

Emerging strategies for targeting cell adhesion in multiple myeloma

Multiple myeloma (MM) is an incurable hematological cancer involving proliferation of abnormal plasma cells that infiltrate the bone marrow (BM) and secrete monoclonal antibodies. The disease is clinically characterized by bone lesions, anemia, hypercalcemia, and renal failure. MM is presently treated with conventional therapies like melphalan, doxorubicin, and prednisone; or novel therapies like thalidomide, lenalidomide, and bortezomib; or with procedures like autologous stem cell transplantation. Unfortunately, these therapies fail to eliminate the minimal residual disease that remains persistent within the confines of the BM of MM patients. Mounting evidence indicates that components of the BM-including extracellular matrix, cytokines, chemokines, and growth factors-provide a sanctuary for subpopulations of MM. This co-dependent development of the disease in the context of the BM not only ensures the survival and growth of the plasma cells but contributes to de novo drug resistance. In addition, by fostering homing, angiogenesis, and osteolysis, this crosstalk plays a critical role in the progression of the disease. Not surprisingly then, over the past decade, several strategies have been developed to disrupt this communication between the plasma cells and the BM components including antibodies, peptides, and inhibitors of signaling pathways. Ultimately, the goal is to use these therapies in combination with the existing antimyeloma agents in order to further reduce or abolish minimal residual disease and improve patient outcomes.

Histone deacetylase inhibitors: potential targets responsible for their anti-cancer effect

The histone deacetylase inhibitors (HDACi) have demonstrated anticancer efficacy across a range of malignancies, most impressively in the hematological cancers. It is uncertain whether this clinical efficacy is attributable predominantly to their ability to induce apoptosis and differentiation in the cancer cell, or to their ability to prime the cell to other pro-death stimuli such as those from the immune system. HDACi-induced apoptosis occurs through altered expression of genes encoding proteins in both intrinsic and extrinsic apoptotic pathways; through effects on the proteasome/aggresome systems; through the production of reactive oxygen species, possibly by directly inducing DNA damage; and through alterations in the tumor microenvironment. In addition HDACi increase the immunogenicity of tumor cells and modulate cytokine signaling and potentially T-cell polarization in ways that may contribute the anti-cancer effect in vivo. Here, we provide an overview of current thinking on the mechanisms of HDACi activity, with attention given to the hematological malignancies as well as scientific observations arising from the clinical trials. We also focus on the immune effects of these agents.