Expression of IL-6 and IL-6 receptors by circulating clonotypic B cells in multiple myeloma: potential for autocrine and paracrine networks

The immune cells in modulating osteoclast formation and bone metabolism

Osteoclasts are pivotal in regulating bone metabolism, with immune cells significantly influencing both physiological and pathological processes by modulating osteoclast functions. This is particularly evident in conditions of inflammatory bone resorption, such as rheumatoid arthritis and periodontitis. This review summarizes and comprehensively analyzes the research progress on the regulation of osteoclast formation by immune cells, aiming to unveil the underlying mechanisms and pathways through which diseases, such as rheumatoid arthritis and periodontitis, impact bone metabolism.

High expression of HOXC6 predicts a poor prognosis and induces proliferation and inflammation in multiple myeloma cells

BACKGROUND

Multiple myeloma (MM) is a common blood system malignance accompanied by monoclonal plasma cell hyperplasia. Homeobox C6 (HOXC6) acts as an oncogene in various cancers, but its function on MM is elusive.

OBJECTIVE

The role of HOXC6 on MM development was clarified in this study.

METHODS

HOXC6 expression and its clinical significance were determined in the peripheral blood samples collected from forty MM patients and thirty healthy adult volunteers. The overall survival was evaluated by Kaplan-Meier analysis with the log-rank test. Cell viability, proliferation and apoptosis were measured by CCK-8, EdU assay and Flow cytometry in U266 and MM.1R cells. Tumor growth was estimated by a xenograft assay. The apoptosis of tumor tissues was evaluated using TUNEL staining. The protein level in tissues was tested by immunohistochemistry.

RESULTS

The HOXC6 expression was elevated in MM and high HOXC6 level was associated with the poor overall survival of MM. Besides, the HOXC6 expression was associated with hemoglobin level and ISS stage. Furthermore, silencing HOXC6 suppressed cell proliferation, induced cell apoptosis, and restrained the secretion of inflammatory factors (TNF-α, IL-6, and IL-8) in MM cells through inactivating the NF-κB pathway. Moreover, silencing HOXC6 suppressed the tumor growth of MM, the inflammatory factors levels, and the activation of NF-κB pathway but enhanced apoptosis in vivo.

CONCLUSION

HOXC6 was elevated in MM and associated with poor survival. Knockdown of HOXC6 suppressed proliferation, inflammation and tumorigenicity of MM cells via inactivating the NF-κB pathway. HOXC6 may be a meaningful target for MM therapy.

Infectious diseases, autoantibodies, and autoimmunity

Infections are known to trigger flares of autoimmune diseases in humans and serve as an inciting cause of autoimmunity in animals. Evidence suggests a causative role of infections in triggering antigen-specific autoimmunity, previous thought mainly through antigen mimicry. However, an infection can induce bystander autoreactive T and B cell polyclonal activation, believed to result in non-pathogenic and pathogenic autoimmune responses. Lastly, epitope spreading in autoimmunity is a mechanism of epitope changes of autoreactive cells induced by infection, promoting the targeting of additional self-epitopes. This review highlights recent research findings, emphasizes infection-mediated autoimmune responses, and discusses the possible mechanisms involved.

Cytokine analysis on a countable number of molecules from living single cells on nanofluidic devices

Analysis of proteins released from living single cells is strongly required in the fields of biology and medicine to elucidate the mechanism of gene expression, cell-cell communication and cytopathology. However, as living single-cell analysis involves fL sample volumes with ultra-small amounts of analyte, comprehensive integration of entire chemical processing for single cells and proteins into spaces smaller than single cells (pL) would be indispensable to prevent dispersion-associated analyte loss. In this study, we proposed and developed a living single-cell protein analysis device based on micro/nanofluidics and demonstrated analysis of cytokines released from living single B cells by enzyme-linked immunosorbent assay. Based on our integration method and technologies including top-down nanofabrication, surface modifications and pressure-driven flow control, we designed and prepared the device where pL-microfluidic- and fL-nanofluidic channels are hierarchically allocated for cellular and molecular processing, respectively, and succeeded in micro/nanofluidic control for manipulating single cells and molecules. 13-unit operations for pL-cellular processing including single-cell trapping and stimulation and fL-molecular processing including fL-volumetry, antigen-antibody reactions and detection were entirely integrated into a microchip. The results suggest analytical performances for countable interleukin (IL)-6 molecules at the limit of detection of 5.27 molecules and that stimulated single B cells secrete 3.41 IL-6 molecules per min. The device is a novel tool for single-cell targeted proteomics, and the methodology of device integration is applicable to other single-cell analyses such as single-cell shotgun proteomics. This study thus provides a general approach and technical breakthroughs that will facilitate further advances in micro/nanofluidics, single-cell life science research, and other fields.

Response to pneumococcal vaccination in multiple myeloma

Background

Streptococcus pneumoniae infection causes morbidity and mortality in multiple myeloma patients. Pneumococcal vaccination is commonly given to immunocompromised myeloma patients; however response data are sparse. Here, we present longitudinal response data to pneumococcal vaccination in multiple myeloma patients.

Method

Twenty‐eight multiple myeloma patients were included, 25 of whom were newly diagnosed. All the patients received two vaccines Prevnar13® and Pneumo23®. Serotype‐specific IgG was measured by ELISA for all 23 vaccine serotypes at baseline, and then sequentially at different time points postvaccination until treatment ended. Response to vaccination is available for 20 patients. The primary endpoint was the incidence rate of patients who obtained an isotype response serum concentration after vaccination. Secondary endpoints included detailed isotype increase, time to first increase, further assessment of a decreased anti‐pneumococcal serum concentrations following treatment including autologous stem cell transplantation (ASCT), rate of infection with a special attention to pneumococcal infection.

Results

The median age was 66 years and the male to female ratio was 0.6. Anti‐pneumococcal capsular polysaccharide (anti‐PCP23) IgG, IgG2, IgA, and IgM responses were detected within 1 week postvaccination. Response to at least one subtype of antibody was obtained in 85% (n = 17) of patients, for at least two subtypes in 65% (n = 13), for at least three subtypes in 55% (n = 11), and 2 patients responded to all four subtypes. The median increase in the concentration of anti‐PCP23 isotypes was threefold following vaccination, with the highest increase observed when Pneumo23® was given more than 30 days after Prevnar13®. The anti‐pneumococcal geometric mean concentration decreased significantly for all subtypes over time independently of treatment approaches.

Conclusion

Myeloma has the ability to demonstrate a response to pneumococcal vaccine, independently of preexisting hypogammaglobulinemia and possibly of treatment‐induced immunodepression. We also observed a drop in the serum response overtime and following autologous transplantation. Further studies in larger sample are needed to understand the benefit of vaccination strategies in these patients.

Elevated pre-transplant C-reactive protein identifies a high-risk subgroup in multiple myeloma patients undergoing delayed autologous stem cell transplantation

The significance of elevated C-reactive protein (CRP) prior to autologous stem cell transplantation (ASCT) in multiple myeloma (MM) has not been studied. We analyzed 1111 MM patients who underwent ASCT at Mayo Clinic from 2007 to 2015. A total of 840 patients (76%) received early ASCT (⩽12 months from diagnosis) and 271 patients (24%) received delayed ASCT (>12 months from diagnosis). Elevated CRP (> upper normal limit (8 mg/L)) was seen in 14% and 22% of patients undergoing early and delayed ASCT, respectively (P=0.003). There was no correlation of CRP with pre-transplant response, bone marrow plasma cell percentage or labeling index. Patients with an elevated CRP had a higher likelihood of having circulating plasma cells prior to ASCT (33 vs 19%; P<0.001). In the early ASCT cohort, the median overall survival (OS) in patients with normal and elevated CRP was not reached and 91 months respectively (P=0.011). In the delayed ASCT cohort, the median OS in respective groups were 73 and 30 months respectively (P<0.001), with elevated CRP being an independent prognostic marker on multivariate analysis (hazard ratio 2.0; 95% confidence interval, 1.0-3.8; P=0.045). Elevated pre-transplant CRP identifies a high-risk population especially in patients undergoing delayed ASCT and should be incorporated in the pre-transplant evaluation.

CD5: A New Partner for IL-6

IL-6-STAT3 axis is known as a key factor of tumor progression. In this issue of Immunity, Yu and colleagues (2016) show that IL-6-binding CD5, rather than IL-6 receptor-α in B cells, amplifies STAT3 activation via JAK-STAT signaling to promote cancer.

IκBε is a key regulator of B cell expansion by providing negative feedback on cRel and RelA in a stimulus-specific manner

The transcription factor NF-κB is a regulator of inflammatory and adaptive immune responses, yet only IκBα was shown to limit NF-κB activation and inflammatory responses. We investigated another negative feedback regulator, IκBε, in the regulation of B cell proliferation and survival. Loss of IκBε resulted in increased B cell proliferation and survival in response to both antigenic and innate stimulation. NF-κB activity was elevated during late-phase activation, but the dimer composition was stimulus specific. In response to IgM, cRel dimers were elevated in IκBε-deficient cells, yet in response to LPS, RelA dimers also were elevated. The corresponding dimer-specific sequences were found in the promoters of hyperactivated genes. Using a mathematical model of the NF-κB-signaling system in B cells, we demonstrated that kinetic considerations of IκB kinase-signaling input and IκBε's interactions with RelA- and cRel-specific dimers could account for this stimulus specificity. cRel is known to be the key regulator of B cell expansion. We found that the RelA-specific phenotype in LPS-stimulated cells was physiologically relevant: unbiased transcriptome profiling revealed that the inflammatory cytokine IL-6 was hyperactivated in IκBε(-/-) B cells. When IL-6R was blocked, LPS-responsive IκBε(-/-) B cell proliferation was reduced to near wild-type levels. Our results provide novel evidence for a critical role for immune-response functions of IκBε in B cells; it regulates proliferative capacity via at least two mechanisms involving cRel- and RelA-containing NF-κB dimers. This study illustrates the importance of kinetic considerations in understanding the functional specificity of negative-feedback regulators.

In multiple myeloma, bone-marrow lymphocytes harboring the same chromosomal abnormalities as autologous plasma cells predict poor survival

Chromosomal abnormalities in plasma cells (PCs) from multiple myeloma (MM) provide a clonal signature to identify malignant cells. BM-lymphocytes from MM aspirates, defined by stringent criteria, were screened for the same chromosomal abnormalities as autologous PCs, including translocations, deletions, and amplifications. For 200 MM patients, we evaluated BM mononuclear cells to identify lymphocytes and autologous PCs on the same slide, followed by interphase fluorescence in situ hybridization to characterize their chromosomal abnormalities. Of all patients having a given chromosomal abnormality(s) in PCs, 45% showed that same abnormality(s) in 2–37% (median = 5%) of BM-lymphocytes. Most translocations, amplifications, and deletions found in MM PCs were also detected in lymphocytes, above the healthy-donor “cut-off.” In patients having chromosomally abnormal CD20⁻ PCs, chromosomally abnormal lymphocytes were found among CD20+ cells confirming them as B cells. Exceptions were amplification of 1q21 or p53 deletion, which characterize PCs but were undetectable in BM-lymphocytes, suggesting that processes leading to these abnormalities may be exclusive to PCs. For a set of 75 patients whose BM-lymphocytes and PCs were analyzed by all six probe sets, 58% of those with abnormal PC also had abnormal BM-lymphocytes harboring from one to five different abnormalities. Confirming the clinical significance of chromosomally abnormal BM-lymphocytes, MM patients having abnormalities in both lymphocytes and PC had significantly worse survival than those with abnormalities only in PC (HR = 2.68). The presence of at least one chromosomal abnormality in BM-lymphocytes appears to have greater clinical significance than particular abnormalities. Chromosomally abnormal BM-lymphocytes correlate with poor outcome and by extrapolation with more aggressive disease.

Multiple myeloma may include microvessel endothelial cells of malignant origin

Multiple myeloma (MM) comprises B and plasma cell compartments that originate from the same parent B cell and share as a cancer signature the same clonotypic IgH VDJ gene rearrangement. Here, we hypothesize that functional interactions between MM plasma cells (MM-PC) and their sister population of MM monocytoid B cells lead to the generation of microvessel endothelium of malignant origin from the monocytoid B cell progenitors. Published reports confirm that endothelial cells can harbor a molecular cancer signature characteristic of a given malignancy. We predict that MM monocytoid B cells-in response to both paracrine and autocrine pathways-contribute to tumor neovascularization in the bone marrow of MM patients. Our hypothesis further predicts that in MM, endothelial cells of malignant origin coexist with those of normal origin. We speculate that malignant development of MM incorporates functionally distinct sister lineages arising from the same MM progenitor that-by working together-ensure survival of the MM clone. We hypothesize that these two arms of the malignant MM clone are functionally interlinked to promote growth of the MM-PC compartment; by providing its own microenvironment, MM clonal evolution may ensure neovascularization to support an expanding malignancy.

Nifuroxazide inhibits survival of multiple myeloma cells by directly inhibiting STAT3

Constitutive activation of the transcription factor STAT3 contributes to the pathogenesis of many cancers, including multiple myeloma (MM). Since STAT3 is dispensable in most normal tissue, targeted inhibition of STAT3 is an attractive therapy for patients with these cancers. To identify STAT3 inhibitors, we developed a transcriptionally based assay and screened a library of compounds known to be safe in humans. We found the drug nifuroxazide to be an effective inhibitor of STAT3 function. Nifuroxazide inhibits the constitutive phosphorylation of STAT3 in MM cells by reducing Jak kinase autophosphorylation, and leads to down-regulation of the STAT3 target gene Mcl-1. Nifuroxazide causes a decrease in viability of primary myeloma cells and myeloma cell lines containing STAT3 activation, but not normal peripheral blood mononuclear cells. Although bone marrow stromal cells provide survival signals to myeloma cells, nifuroxazide can overcome this survival advantage. Reflecting the interaction of STAT3 with other cellular pathways, nifuroxazide shows enhanced cytotoxicity when combined with either the histone deacetylase inhibitor depsipeptide or the MEK inhibitor UO126. Therefore, using a mechanistic-based screen, we identified the clinically relevant drug nifuroxazide as a potent inhibitor of STAT signaling that shows cytotoxicity against myeloma cells that depend on STAT3 for survival.

Multiple Myeloma Includes Phenotypically Defined Subsets of Clonotypic CD20+ B Cells that Persist During Treatment with Rituximab

Potential progenitor B cell compartments in multiple myeloma (MM) are clinically important. MM B cells and some circulating MM plasma cells express CD20, predicting their clearance by treatment with anti-CD20. Here we describe two types of clonotypic CD20+ B cell in peripheral blood of myeloma patients, identified by their expression of CD19 and CD20 epitopes, their expression of CD45RA and their light scatter properties. Thus, the circulating component of the MM clone includes at least two distinct CD19+ CD20+ B cell compartments, as well as CD138+ CD20+ plasma cells. To determine whether either or both B cell subsets and the CD20+ plasma cell subset were depleted by anti-CD20 therapy, they were evaluated before, during and after treatment of patients with rituximab (anti-CD20), followed by quantifying B cell subsets over a 5 month period during and after treatment. Overall, all three types of circulating B lineage cells persist despite treatment with rituximab. The inability of rituximab to prolong survival in MM may result from this failure to deplete CD20+ B and plasma cells in MM.

Induction of the nuclear IκB protein IκB-ζ upon stimulation of B cell antigen receptor

The nuclear IkappaB protein IkappaB-zeta is barely detectable in resting cells and is induced in macrophages and fibroblasts following stimulation of innate immunity via Toll-like receptors. The induced IkappaB-zeta associates with nuclear factor (NF)-kappaB in the nucleus and plays crucial roles in its transcriptional regulation. Here, we examined the induction of IkappaB-zeta in B lymphocytes, one of the major players in adaptive immunity. Upon crosslinking of the surface immunoglobulin complex, IkappaB-zeta mRNA was robustly induced in murine B-lymphoma cell line A20 cells. While the crosslinking activated NF-kappaB and induced its target gene, IkappaB-alpha, co-crosslinking of Fcgamma receptor IIB to the surface immunoglobulin complex inhibited NF-kappaB activation and the induction of IkappaB-zeta and IkappaB-alpha, suggesting critical roles for NF-kappaB in the induction. These results indicate that IkappaB-zeta is also induced by stimulation of B cell antigen receptor, suggesting that IkappaB-zeta is involved in the regulation of adaptive immune responses.

Interleukin-6 induces both cell growth and VEGF production in malignant mesotheliomas

Malignant mesothelioma (MM), an incurable tumor, is reportedly an interleukin-6 (IL-6) secreting tumor. The pathological significance of IL-6 overexpression in this tumor, however, has remained unclear. We investigated the biological functions of IL-6 in mesotheliomas. Five mesothelioma cell lines were analyzed for IL-6 production and IL-6 receptor (IL-6R) expression. Of them, 2 produced high levels of IL-6, 2 produced intermediate levels and 1 cell line showed no secretion. All mesothelioma cell lines used in this study expressed very small amounts of IL-6R mRNA. We compensated for this low level of IL-6R expression in mesotheliomas by adding recombinant soluble IL-6R (sIL-6R) to mediate the IL-6 signal. IL-6 together with sIL-6R was found to promote cell growth of H2052 and H226 MMs classified as high-level IL-6 producers in a dose-dependent manner. Moreover, a humanized anti-IL-6R antibody (MRA) capable of blocking IL-6 signaling suppressed the cell growth of mesotheliomas induced by IL-6/sIL-6R. These findings demonstrate that IL-6 serves as an autocrine growth factor in the development of mesothelioma. In addition, IL-6/sIL-6R stimulation increased the expression of vascular endothelial growth factor (VEGF) in 4 out of 5 cell lines, and this induction was inhibited by MRA treatment. The involvement of the signal transducer and activator of transcription 3 (STAT3) pathway in both cell growth and VEGF induction by IL-6/sIL-6R was verified by dominant negative STAT3 transduction combined with adenovirus gene-delivery methods. Although IL-6 induces VEGF through the JAK2/STAT3 pathway, anti-VEGF antibody could not inhibit the IL-6-induced cell growth observed in H2052 and H226. We concluded that IL-6-dependent growth does not occur via VEGF induction. These results suggest that treatment with anti-IL-6R antibody may constitute a potential molecular targeting therapy for MMs.

Thymoglobulin targets multiple plasma cell antigens and has in vitro and in vivo activity in multiple myeloma

Multiple myeloma is characterized by the proliferation of clonal plasma cells that have a heterogeneous expression of various cell surface markers, precluding successful use of monoclonal antibodies for therapeutic targeting of the tumor cell. Thymoglobulin (rabbit-derived polyclonal anti-thymocyte globulin), by virtue of its method of preparation, contains antibodies against several B-cell and plasma cell antigens and offers an attractive option for immunotherapy of myeloma. Here, we demonstrate potent anti-myeloma activity of the rabbit anti-thymocyte globulin preparation Thymoglobulin in vitro and in vivo in an animal model of myeloma. Thymoglobulin was able to induce dose- and time-dependent apoptosis of several myeloma cell lines, including those resistant to conventional anti-myeloma agents. Importantly, the anti-myeloma activity was preserved even when myeloma cells were grown with different cytokines demonstrating the ability to overcome microenvironment-mediated resistance. Thymoglobulin induced apoptosis of freshly isolated primary myeloma cells from patients. Using a competitive flow cytometric analysis, we were able to identify the potential antigen targets for Thymoglobulin preparation. Finally, in a plasmacytoma mouse model of myeloma, Thymoglobulin delayed the tumor growth in a dose-dependent manner providing convincing evidence for continued evaluation of this agent in the clinic in patients with myeloma, either alone or in combination with other agents.

Atiprimod blocks STAT3 phosphorylation and induces apoptosis in multiple myeloma cells

Multiple myeloma (MM) accounts for 1 % of all cancer deaths. Although treated aggressively, almost all myelomas eventually recur and become resistant to treatment. Atiprimod (2-(3-Diethylaminopropyl)-8,8-dipropyl-2-azaspiro[4,5] decane dimaleate) has exerted anti-inflammatory activities and inhibited oeteoclast-induced bone resorption in animal models and been well tolerated in patients with rheumatoid arthritis in phase I clinical trials. Therefore, we investigated its activity in MM cells and its mechanism of action. We found that Atiprimod inhibited proliferation of the myeloma cell lines U266-B1, OCI-MY5, MM-1, and MM-1R in a time- and dose-dependent manner. Atiprimod blocked U266-B1 myeloma cells in the G₀/G₁ phase, preventing cell cycle progression. Furthermore, Atiprimod inhibited signal transducer and activator of transcription (STAT) 3 activation, blocking the signalling pathway of interleukin-6, which contributes to myeloma cell proliferation and survival, and downregulated the antiapoptotic proteins Bcl-2, Bcl-X_L, and Mcl-1. Incubation of U266-B1 myeloma cells with Atiprimod induced apoptosis through the activation of caspase 3 and subsequent cleavage of the DNA repair enzyme poly(adenosine diphosphate-ribose) polymerase. Finally, Atiprimod suppressed myeloma colony-forming cell proliferation in fresh marrow cells from five patients with newly diagnosed MM in a dose-dependent fashion. These data suggest that Atiprimod has a role in future therapies for MM.

IL-6 activates serum and glucocorticoid kinase via p38alpha mitogen-activated protein kinase pathway

Interleukin-6 (IL-6) has been implicated as an autocrine factor involved in growth of several human cancers, such as tumors arising from the biliary tract or cholangiocarcinoma. In malignant biliary tract epithelia, IL-6 activates the p38 MAPK pathway, which mediates a dominant survival signaling pathway. Serum and glucocorticoid-stimulated kinase (SGK) has been implicated as a survival kinase, but its role in survival signaling by IL-6 is unknown. After IL-6 stimulation, p38 MAPK activation preceded phosphorylation of SGK at Ser78. Pretreatment with the pharmacological inhibitors of p38 MAPK SB-203580 or SB-202190 blocked IL-6-induced SGK phosphorylation at Ser78 and SGK activation. Overexpression of p38alpha increased constitutive SGK phosphorylation at Ser78, whereas dominant negative p38alpha MAPK blocked IL-6-induced SGK phosphorylation and nuclear translocation. Interestingly, in addition to stimulating SGK phosphorylation, both IL-6 stimulation and p38alpha MAPK overexpression increased SGK mRNA and protein expression. An increase in p38 MAPK and SGK occurred following enforced expression of IL-6 in vivo. Furthermore, inhibition of SGK expression by siRNA increased toxicity due to chemotherapeutic drugs. Taken together, these data identify SGK as both a downstream kinase substrate as well as a transcriptionally regulated gene target of p38 MAPK in response to IL-6 and support a role of SGK during survival signaling by IL-6 in human cancers, such as cholangiocarcinoma.

The uptake kinetics and immunotoxic effects of microcystin-LR in human and chicken peripheral blood lymphocytes in vitro

Microcystin-LR is a cyanobacterial heptapeptide that presents acute and chronic hazards to animal and human health. We investigated the influence of this toxin on human and chicken immune system modulation in vitro. Peripheral blood lymphocytes were treated with microcystin-LR at environmentally relevant doses of 1, 10 and 25 microg/ml for 12, 24, 48, 72 h (for proliferation assay cells were treated for 72 h). T-cell and B-cell proliferation as well as apoptosis and necrosis were determined in human and chicken samples. IL-2 and IL-6 production by human lymphocytes also was measured. In addition, uptake kinetics of microcystin-LR into human and chicken peripheral blood lymphocytes were calculated by Liquid Chromatography (LS) /Mass Spectrometry (MS) analysis. At the highest dose microcystin-LR decreased T-cell proliferation and all doses of microcystin-LR inhibited B-cell proliferation. The frequency of apoptotic and necrotic cells increased in a dose and time-dependent manner. Human lymphocytes responded to stimulation with microcystin-LR by increased production of IL-6 and decreased production of IL-2. Human lymphocytes were able to uptake from 0.014 to 1.663 microg/ml and chicken lymphocytes from 0.035 to 1.733 microg/ml of the microcystin-LR added to the cultures, depending on the treatment time and dose. In conclusion, microcystin-LR acted as an immunomodulator in cytokine production and down-regulated lymphocyte functions by induction of apoptosis and necrosis. However, further studies dealing with the influence of microcystin-LR on expression cytokine genes and transcription factors are necessary to confirm these hypotheses.

Nonirradiated NOD/SCID-human chimeric animal model for primary human multiple myeloma: a potential in vivo culture system

The NOD/SCID human chimeric animal model was generated by implanting of human fetal bones (FBs) into subcutaneous sites of NOD/SCID mice (NOD/SCID-hu(+)), followed by inoculation of primary bone marrow mononuclear cells (BMNCs) obtained from patients with multiple myeloma (MM) into the FBs. The BMNCs from 30 patients with MM were inoculated, and 28 (93%) of them revealed evidence of tumor growth of myeloma cells (MCs) in the NOD/SCID-hu(+) mice. Intriguingly, 17 (61%) of the 28 patients' BMNCs inoculated developed not only myeloma in the bone marrow of the FBs, but also extramedullary macrotumors (EMTs) along the periosteum of the FBs. The tumor cells in these EMTs had plasmacytoid morphology and preserved antigens and cytogenetics similar, if not identical, to those in the parent MCs. Moreover, small tumor blocks from nine EMTs were transplanted into subcutaneous sites of subsequent recipient NOD/SCID mice without human FBs (NOD/SCID-hu(-)), and all but one grew successfully. Two of the EMTs have been maintained in the animal model for more than 12 months. The NOD/SCID-hu(+) chimeric animal model is highly efficient for growth of primary MCs and presents clinical features of human MM. The engrafted MCs can be maintained subsequently in NOD/SCID-hu(-) mice as in vivo culture.

In vitro IL-6 production by EBV-immortalized B lymphocytes from young and elderly people genotyped for -174 C/G polymorphism in IL-6 gene: a model to study the genetic basis of inflamm-aging

In the present investigation we analysed Interleukin 6 (IL-6) in vitro production by Epstein-Barr virus (EBV)-immortalized B lymphocytes established from 43 subjects, 15 young people and 28 elderly people, including 18 centenarians, after 3, 6, 9, 24, 48 and 72 h of culture. The subjects were genotypized for the C to G transition at nucleotide -174 of IL-6 gene promoter (-174 C/G) and were classified as C allele carriers (C+) and non-carriers (C-). We found that: (i) the interindividual difference in in vitro IL-6 production was wider in elderly individuals in respect to young individuals, leading to different coefficient of variation in the two groups; (ii) the -174 C/G polymorphism had an age-related effect on IL-6 in vitro production. Only among C- people, cells from elderly subjects produced significant higher level of IL-6 than cells from young subjects. These data are consistent with our previous results regarding the IL-6 serum levels in a large group of people of different age, including centenarians. Thus, the EBV-immortalized B lymphocytes can be considered a useful in vitro model for studying the genetic control of IL-6 production and its changes with age.

Circulating interleukin-6 predicts survival in patients with metastatic breast cancer

Interleukin-6 (IL-6) is a multifunctional cytokine produced by macrophages, T cells, B cells, endothelial cells and tumour cells. Interleukin-6 is able to promote tumour growth by upregulating anti-apoptotic and angiogenic proteins in tumour cells. In murine models it has been demonstrated that antibodies against IL-6 diminish tumour growth. Several reports have highlighted the prognostic importance of IL-6 in e.g., prostate and colon cancer. We addressed prospectively the prognostic significance of serum IL-6 (sIL-6), measured at diagnosis of metastasis, in 96 unselected and consecutive patients with progressive metastatic breast cancer before the initiation of systemic therapy. The median sIL-6 value for the breast cancer population was 6.6 +/- 2.1 pg/ml. Patients with 2 or more metastatic sites had higher sIL-6 values compared to those with only 1 metastatic site (respectively 8.15 +/- 1.7 pg/ml and 3.06 +/- 6.6 pg/ml; p < 0.001). Patients with liver metastasis (8.3 +/- 2.4 pg/ml), with pleural effusions (10.65 +/- 9.9 pg/ml) and with dominant visceral disease (8.15 +/- 3.3 pg/ml) had significantly higher values compared to those without liver metastases (4.5 +/- 3.4 pg/ml; p = 0.001), without pleural effusions (5.45 +/- 1.5 pg/ml; p = 0.0077) and with dominant bone disease (4.5 +/- 1.4 pg/ml; p = 0.007) respectively. No correlation between sIL-6 and age, menopausal status, performance status, tumour grade, body-mass index, histology and hormone receptor status was found. Multivariate analysis showed that high levels of serum IL-6 have independent prognostic value. We conclude that circulating IL-6 is associated with worse survival in patients with metastatic breast cancer and is correlated with the extent of disease.

Inhibition of growth and sensitization to cisplatin-mediated killing of ovarian cancer cells by polyphenolic chemopreventive agents

The polyphenolic compounds curcumin and quercetin increased sensitivity of ovarian cancer cells (CAOV3 and SKOV3) to cisplatin. The effect was obtained when the compounds were added simultaneously with cisplatin, as well as when they were added 24 h before. High serum levels of certain cytokines, for example interleukin-6 (IL-6), have been associated with poor prognosis and cisplatin resistance in various forms of cancer. Furthermore, it has been hypothesized that cytokines may increase proliferation, metastasis, and stimulate production of detoxification enzymes and multi-drug resistant proteins. Curcumin inhibits the production of many cytokines. The two ovarian cell lines differ significantly in IL-6 production, and correspondingly the high producer, CAOV3, was less susceptible to cisplatin. Curcumin inhibited the production of IL-6 in this cell suggesting that one of the mechanisms for synergy between cisplatin and curcumin was by reducing the autologous production of IL-6. However, the synergy was also observed in the low IL-6 producer, SKOV3, indicating that the action was most probably a result of multiple targeting. In sum, this study suggests that the compounds, curcumin and quercetin, potentially may be useful for enhancing drug sensitivity in certain cancer.

Endocytosis of light chains induces cytokines through activation of NF-kappaB in human proximal tubule cells

BACKGROUND

In proteinuric states increased cytokine production through endocytosis of filtered proteins by proximal tubule cells (PTCs) has been proposed as a major mechanism mediating tubulointerstitial injury and progressive kidney disease. We studied the effects of six different light chains (LCs) on the production of cytokines in cultured human PTCs.

METHODS

LCs were isolated and purified from the urine of patients with myeloma and human PTCs were exposed to either LC or human serum albumin (HSA) for up to 24 hours. LC endocytosis was monitored by immunocytochemistry. Cytokines were determined by enzyme-linked immunosorbent assay (ELISA) in the supernatants and activation of nuclear factor-kappa B (NF-kappaB) was detected by electrophoretic mobility shift assays (EMSA) and immunocytochemistry.

RESULTS

Endocytosis of LCs induced the release of interleukins (IL) IL-6, IL-8 and monocyte chemoattractant protein-1 (MCP-1); however, there was considerable variability among the six different LCs. In contrast, HSA had no effect on cytokine production even at very high concentrations. Removal of LC-containing media resulted in cessation of IL-6 release. LC-induced cytokine release was associated with nuclear translocation of NF-kappaB subunits p50 and p65, as demonstrated by both EMSA and immunocytochemistry. Inhibitors of NF-kappaB, aspirin and pyrrolidineditiocarbamate (PDTC) markedly suppressed LC-induced cytokine production.

CONCLUSION

LC endocytosis leads to production of inflammatory cytokines through activation of NF-kappaB. This may be an important mechanism of chronic tubulointerstitial inflammation process commonly seen in multiple myeloma. These findings also point out a potential role by filterable low-molecular-weight proteins, like LCs, in PTC injury during all proteinuric diseases.

Thalidomide in the management of multiple myeloma

The discovery that multiple myeloma is associated with new vessel formation and is correlated with survival and proliferation led initially to the use of thalidomide for patients with relapsed or refractory disease. The outcome with conventional chemotherapy in this setting has historically been very poor. New insights into the biology of the disease suggests that thalidomide may work via a number of other mechanisms and the advent of the thalidomide analogues with their differential effects on survival and proliferation pathways has opened up a new era in the understanding and treatment of the disease. The encouraging results from phase I/II trials of these agents has meant that for the first time in 50 years there is the opportunity to improve outcome. Further work is in progress to define how best to use these drugs and their role in treatment at different stages of the disease.

IL-6 rescues the hyporesponsiveness of c-Rel deficient B cells independent of Bcl-xL, Mcl-1, and Bcl-2

The hematopoietically restricted member of the NF-kappaB/Rel family, c-Rel, is essential for B cell survival and proliferation. Here we demonstrate that the production of the interleukins 6, 10, and 15 (IL-6, IL-10, and IL-15) are diminished in c-Rel(-/-) B lymphocytes. In a manner similar to that seen in IL-6(-/-) B cells, resultant STAT activation is reduced in c-Rel(-/-) B cells following B cell receptor (BCR) ligation. Addition of either exogenous IL-6 or IL-10, but not IL-15, partially restores proliferation, and this occurs through enhanced cell survival rather than promoting cell cycle progression. This increase in viability occurs independently of Bcl-xL and Mcl-1 expression though, two survival genes reported to be downstream of IL-6 signaling. Nonetheless, transgenically expressed Bcl-xL, a direct c-Rel target gene in B cells, corrects not only the survival defect of c-Rel deficiency, but also partially ameliorates hypoproliferation. Together IL-6 and Bcl-xL are additive but incomplete in the restoration of proliferation. Known deficits in the induction of several key cell cycle components in c-Rel(-/-)B cells are not corrected upon treatment with exogenous cytokine. Together, these data demonstrate that IL-6 enhances B cell responses by employing multiple survival factors.