Interleukin-6 inhibits apoptosis of malignant plasma cells

Calculated haemorheological profile and laboratory parameters in new diagnosed multiple myeloma patients: retrospective analysis according to survival

Background

Multiple myeloma is a malignant haematological neoplasm characterised by clonal proliferation of plasma cells, with a complex clinical picture, and a significant impact on patient survival, in which the prognosis evaluation of patients is of great importance.

Objectives

In this single-centre retrospective analysis, performed in a group of newly diagnosed multiple myeloma patients, we examined several clinical and laboratory parameters in order to evaluate their trend according to survival of patients.

Design

We collected data from 190 newly diagnosed multiple myeloma evaluated at the Hematology Division of the 'Paolo Giaccone' University Hospital of Palermo from 1 January 2017 to 30 September 2022. Specifically, we performed our analysis in the entire cohort of patients and also in the specific disease isotype.

Methods

We evaluated simple and low-cost laboratory and haemorheological parameters, the latter obtained in a calculated way. The primary endpoint was to evaluate the trend and the differences of these parameters in the study population, divided into two specific groups, deceased and survivors after a specific observation period of almost 7 years.

Results

In the entire cohort of multiple myeloma patients, we observed a mortality rate of 40%, of whom 36.4% were men and 43.1% were women. Among the patients who died, in comparison with those who survived, it is significantly evident the increase in age, in red cell distribution width (RDW), RDW%/albumin ratio and in the RDW%/haemoglobin ratio; moreover, in the same patients subgroup, we observed a reduction in haematocrit, total serum protein, calculated whole blood viscosity (evaluated according to the de Simone formula), serum albumin, albumin/fibrinogen ratio and in haemoglobin levels.

Conclusion

The obtained data can represent a possible starting point for subsequent targeted analyses, aimed at studying the prognostic value of each individual parameter considered, favouring an increasingly complete and immediate prognostic evaluation of patients.

Optimal cut-off values and diagnostic significance of clinical laboratory indicators in newly diagnosed multiple myeloma

OBJECTIVE

This study aims to identify clinical laboratory parameters for the diagnosis of newly diagnosed multiple myeloma (NDMM), establish optimal cutoffs for early screening, and develop a diagnostic model for precise diagnosis.

METHODS

The study conducted a retrospective analysis of 279 NDMM patients and 553 healthy subjects at Zhejiang Province People's Hospital between January 2008 and June 2023. Multifactor LR was employed to explore clinical laboratory indicators with diagnostic value for NDMM, determine optimal cutoff values and contract a diagnostic model. The diagnostic efficacy and clinical utility were evaluated using receiver operating characteristic curves (ROC), sensitivity, specificity, and other indicators.

RESULTS

Multifactor analysis revealed that hemoglobin (Hb), albumin (Alb), and platelet distribution width (PDW) were significant diagnostic factors for NDMM. Optimal cutoff values for Hb, Alb, and PDW in MM diagnosis were determined, and the results showed a significant increase in the probability of NDMM diagnosis when Alb was below 39.3 g/L, Hb was below 11.6 g/dL, and PDW was below 14.1 fL. The diagnostic model constructed from the development cohort demonstrated a high area under the ROC curve of 0.960 (95% CI 0.942-0.978) and exhibited good sensitivity (0.860), specificity (0.957). The area under the curve (AUC) value of the diagnostic model in the external validation cohort was 0.979, confirming its good diagnostic efficacy and generalization.

CONCLUSIONS

The optimal cutoff values for Hb, Alb, and PDW and the diagnostic model designed in the study provided good accuracy and sensitivity for the initial screening and diagnosis of NDMM.

Myelodysplastic syndromes del(5q): Pathogenesis and its therapeutic implications

Myelodysplastic syndromes (MDS) encompass a heterogeneous set of acquired bone marrow neoplastic disorders characterized by ineffective hematopoiesis within one or more bone marrow lineages. Nearly half of MDS patients carry cytogenetic alterations, with del(5q) being the most prevalent. Since its first description, del(5q) was consistently correlated with a typical clinical phenotype marked by anemia, thrombocytosis, and a low risk of evolving into acute leukemia. Presently, the World Health Organization (WHO) classification of myeloid neoplasms recognizes a specific subtype of MDS known as "myelodysplastic neoplasm with low blast and isolated del(5q)" identified by the sole presence of 5q deletion or in combination with one other abnormality excluding -7/del(7q). Several studies have sought to unravel the biological processes triggered by del(5q) in the development of MDS, revealing the involvement of various genes localized in specific regions of chromosome 5 referred to as common deleted regions (CDR). This intricate biological landscape makes the MDS cells with del(5q) exceptionally sensitive to lenalidomide. Several studies have confirmed the efficacy of lenalidomide in this context. Regrettably, the response to lenalidomide is not conclusive, prompting ongoing research into biological mechanisms that drive patients toward leukemia and strategies to circumvent lenalidomide resistance and disease progression.

Descriptive analysis and prognostic factors in cats with myeloma-related disorders: A multicenter retrospective study of 50 cases

BACKGROUND

Myeloma-related disorders (MRDs) are rare and poorly documented neoplasms of cats.

HYPOTHESIS/OBJECTIVES

To describe clinical, clinicopathologic, and imaging findings, response to treatment, and survival time and to identify factors associated with shorter outcomes in cats with MRD.

ANIMALS

Fifty cats with a diagnosis of MRD.

METHODS

Cats with paraproteinemia confirmed by serum protein electrophoresis (SPE) and either intramedullary plasmacytosis >10%, marked cytonuclear atypia with intramedullary plasmacytosis that ranged between 5% and 10%, or cytologically or histologically confirmed visceral infiltration were retrospectively included from several veterinary referral centers.

RESULTS

Bone marrow plasmacytosis and splenic or hepatic involvement were present in 17/27 cats (63%), 36/42 cats (86%), and 27/38 cats (71%), respectively. Anemia was reported in 33/49 cats (67%) and thrombocytopenia in 16/47 cats (34%). Some of the treatments that the cats received included melphalan and prednisolone (n = 19), cyclophosphamide and prednisolone (n = 10), chlorambucil and prednisolone (n = 4), prednisolone (n = 4), or other (n = 4). The overall response rates to melphalan, cyclophosphamide, and chlorambucil in combination with prednisolone were 87%, 90%, and 100%, respectively. Adverse events to melphalan or cyclophosphamide occurred in 65% and 23% of cats, respectively. Median survival time was 122 days (range, 0-1403) and was not significantly associated with chemotherapy protocol. Anemia (hazard ratio [HR], 3.1; 95% confidence interval [CI], 1.0-9.8) and thrombocytopenia (HR, 2.7; 95% CI, 1.2-6.0) were risk factors for shorter survival.

CONCLUSIONS AND CLINICAL IMPORTANCE

Our study confirmed the guarded prognosis of MRD in cats and identified risk factors for shorter survival times.

The long-term mediation role of cytokines on the causal pathway from maternal gestational age to offspring eye diseases: Lifecourse-Network Mendelian randomization

BACKGROUND

Gestational duration has a significant impact on eye diseases. A large number of evidences suggest that cytokines are associated with gestational duration and eye diseases. However, the causal relationships among cytokines, maternal gestational impairment and offspring eye diseases remain unclear.

METHODS

We performed lifecourse-network Mendelian randomization (MR) to explore the causal relationships between maternal gestational duration (from the Early Growth Genetics (EGG) Consortium and the Lundbeck Foundation Initiative for Integrative Psychiatric Research (iPSYCH) study, N = 84,689), neonatal/adult cytokines (from the NHGRI-EBI Catalog, N = 764/4,618), and adult eye diseases (from FinnGen consotium, N = 309,154) using summary-level data from large genome-wide association studies. Multiplicative random effects inverse variance weighted (IVW) and multivariable-IVW methods were the main analysis methods, and the other 15 pleiotropy-robust methods, weak IV-robust methods, and outliers-robust methods were used as auxiliary methods.

RESULTS

Maternal gestational age (early preterm birth, preterm birth, gestational duration, and post-term birth) had a causal relationship with 42 eye diseases. Four neonatal cytokines, Tumor Necrosis Factor-α(TNF-α), IL10, GROA, and CTACK, as well as four adult cytokines, CTACK, IL10, IL12p70 and IL6 are mediators in the causal relationships between early preterm birth and preterm birth in eight eye diseases. However, after adjusting for these mediators, a null direct causal effect of early preterm birth and preterm birth on eight eye diseases was found. In addition, there was no mediator in the causal relationship between gestational duration and post-term birth to eye diseases.

CONCLUSION

The effects of maternal gestational duration on offspring eye diseases through cytokines are long-term and life-course effects.

Multiple Myeloma and Kidney Impairment at Diagnosis: A Nephrological Perspective from an Eastern European Country

Background and Objectives: The clinical presentation and survival factors in patients with myeloma-related kidney impairment (MRKI) at diagnosis remain a topic of ongoing research, given the complex interplay between nephrology and hematology. To date, no studies have specifically reported outcomes for these patients in Eastern Europe. Materials and Methods: We conducted a retrospective, unicentric study of consecutive newly diagnosed patients with MRKI in our tertiary nephrology service in Romania between 2015 and 2020; follow-up extended until 1 September 2022, covering a study period of 90 months. Results: We identified 89 consecutive patients with MRKI (median age 66 years, 38% male, median eGFR 5 mL/min). The majority of patients had arterial hypertension (71%) and systemic atherosclerosis (58%), and the most frequent clinical features at presentation were asthenia (75%) and bone pain (51%). Light-chain-restricted myeloma was the most common type (55%), with kappa free light chain being more frequent (53%). Among the patients, 81% presented with acute kidney injury (AKI), and 38% required hemodialysis at diagnosis. During the study period, 65% of the patients died, and hypoalbuminemia and the need for hemodialysis at diagnosis were significantly associated with mortality in multivariate analysis. Conclusions: Patients with MRKI who present to the nephrologist more frequently exhibit light chain restriction and most often present with AKI, with one-third requiring hemodialysis at diagnosis. Moreover, hypoalbuminemia and the initiation of hemodialysis at diagnosis were significantly associated with increased mortality.

CD8+ T Cell Senescence: Lights and Shadows in Viral Infections, Autoimmune Disorders and Cancer

CD8⁺ T lymphocytes are a heterogeneous class of cells that play a crucial role in the adaptive immune response against pathogens and cancer. During their lifetime, they acquire cytotoxic functions to ensure the clearance of infected or transformed cells and, in addition, they turn into memory lymphocytes, thus providing a long-term protection. During ageing, the thymic involution causes a reduction of circulating T cells and an enrichment of memory cells, partially explaining the lowering of the response towards novel antigens with implications in vaccine efficacy. Moreover, the persistent stimulation by several antigens throughout life favors the switching of CD8⁺ T cells towards a senescent phenotype contributing to a low-grade inflammation that is a major component of several ageing-related diseases. In genetically predisposed young people, an immunological stress caused by viral infections (e.g., HIV, CMV, SARS-CoV-2), autoimmune disorders or tumor microenvironment (TME) could mimic the ageing status with the consequent acceleration of T cell senescence. This, in turn, exacerbates the inflamed conditions with dramatic effects on the clinical progression of the disease. A better characterization of the phenotype as well as the functions of senescent CD8⁺ T cells can be pivotal to prevent age-related diseases, to improve vaccine strategies and, possibly, immunotherapies in autoimmune diseases and cancer.

Aging-associated immune system changes in multiple myeloma: The dark side of the moon

Multiple myeloma (MM) is a disease of the elderly. Changes that occur in the immune system with aging, also known as immunosenescence, have been associated with decreased tumor immunosurveillance and are thought to contribute to the development of MM and other cancers in the elderly. Once MM establishes itself in the bone marrow, immunosenescence related changes have been observed in the immune tumor microenvironment (iTME) and are driven by the malignant cells. The efficacy of novel immunotherapies used to treat MM has been blunted by detrimental iTME changes that occur at later disease stages and are, to some extent, driven by prior therapies. In this review, we discuss general changes that occur in the immune system with aging as well as our current knowledge of immunosenescence in MM. We discuss the differences and overlap between T cell senescence and exhaustion as well as potential methods to prevent or reverse immunosenescence. We focus predominantly on T cell immunosenescence which has been better evaluated in this disease and is more pertinent to novel MM immunotherapies. Our lack of understanding of the drivers of immunosenescence at each stage of the disease, from precursor stages to heavily pretreated MM, represents a major barrier to improving the efficacy of novel and existing therapies.

A Comprehensive Review of the Genomics of Multiple Myeloma: Evolutionary Trajectories, Gene Expression Profiling, and Emerging Therapeutics

Multiple myeloma (MM) is a blood cancer characterized by the accumulation of malignant monoclonal plasma cells in the bone marrow. It develops through a series of premalignant plasma cell dyscrasia stages, most notable of which is the Monoclonal Gammopathy of Undetermined Significance (MGUS). Significant advances have been achieved in uncovering the genomic aberrancies underlying the pathogenesis of MGUS-MM. In this review, we discuss in-depth the genomic evolution of MM and focus on the prognostic implications of the accompanied molecular and cytogenetic aberrations. We also dive into the latest investigatory techniques used for the diagnoses and risk stratification of MM patients.

Signaling Pathway Mediating Myeloma Cell Growth and Survival

Simple Summary

The bone marrow (BM) microenvironment plays a crucial role in pathogenesis of multiple myeloma (MM), and delineation of the intracellular signaling pathways activated in the BM microenvironment in MM cells is essential to develop novel therapeutic strategies to improve patient outcome.

Abstract

The multiple myeloma (MM) bone marrow (BM) microenvironment consists of different types of accessory cells. Both soluble factors (i.e., cytokines) secreted from these cells and adhesion of MM cells to these cells play crucial roles in activation of intracellular signaling pathways mediating MM cell growth, survival, migration, and drug resistance. Importantly, there is crosstalk between the signaling pathways, increasing the complexity of signal transduction networks in MM cells in the BM microenvironment, highlighting the requirement for combination treatment strategies to blocking multiple signaling pathways.

Anticancer Activity and Underlying Mechanism of Phytochemicals against Multiple Myeloma

Multiple myeloma (MM)-a common hematologic malignancy of plasma cells-accounts for substantial mortality and morbidity rates. Due to the advent of novel therapies such as immunomodulatory drugs (IMiDs), proteasome inhibitors (PIs), and monoclonal antibodies (mAbs), response rates were increased and free survival and overall survival have been elevated. However, adverse events including toxicity, neuropathy or continuous relapse are still problems. Thus, development of novel drugs which have less side effects and more effective is needed. This review aims to recapitulate the pharmacologic anti-MM mechanisms of various phytochemicals, elucidating their molecular targets. Keywords related to MM and natural products were searched in PUBMED/MEDLINE. Phytochemicals have been reported to display a variety of anti-MM activities, including apoptosis, cell cycle arrest, antiangiogenesis, and miRNA modulation. Some phytochemicals sensitize the conventional therapies such as dexamethasone. Also, there are clinical trials with phytochemicals such as agaricus, curcumin, and Neovastat regarding MM treatment. Taken together, this review elucidated and categorized the evidences that natural products and their bioactive compounds could be potent drugs in treating MM.

Effect of levamisole on expression of CD138 and interleukin-6 in human multiple myeloma cell lines

INTRODUCTION

Multiple myeloma (MM) is a B-cell malignancy accounting for 0.8% of all cancer deaths globally. This malignancy is characterized by lytic bone disease renal insufficiency, anemia, hypercalcemia, and immunodeficiency. The myeloma cells have enhanced expression of CD138. CD138 is a transmembrane heparin sulfate glycoprotein expressed on different types of adherent and nonadherent cells.CD138 is used as a standard marker for identification of tumor cells.

AIMS AND OBJECTIVES

Despite introduction of many therapeutic agents, the management of multiple myeloma (MM) remains a challenge and search for new therapeutic agents is in progress. In this study, we attempted to evaluate the effect of an alkaline phosphatase inhibitor, levamisole on expression of CD138, and level of interleukin-6 (IL-6) in human MM cell lines RPMI 8226 and U266 B1.

MATERIAL AND METHODS

U266B1 and RPMI 8226 cell lines were obtained from the National Centre for Cell Sciences, Pune. Alkaline phosphatase assay, Interleukin-6 assay and CD138 expression on myeloma cells by flow cytometry were investigated when the cells were exposed to Levamisole.

RESULTS

Levamisole-mediated growth inhibition of myeloma cells in vitro is associated with a loss of CD138 and increased IL-6 secretion. The increased secretion of IL-6 by myeloma cells could be an attempt to protect themselves from apoptosis.

CONCLUSION

Levamisole inhibited CD138 expression and affected the levels of IL-6 in a dose-dependent manner. The results of the present study add new dimension to levamisole's mode of action as inhibitor of CD138 and IL-6 and as an antiapoptotic agent.

Glucocorticoids in multiple myeloma: past, present, and future

Glucocorticoids are a backbone of treatment for multiple myeloma in both the upfront and relapsed/refractory setting. While glucocorticoids have single agent activity in multiple myeloma, in the modern era, they are paired with novel agents to induce high clinical response rates. On the other hand, toxicities of steroid therapy limit high dose delivery and impact patient quality of life. We provide a history of steroid use in multiple myeloma with the aim to understand how steroids have emerged and persisted in the treatment of multiple myeloma. We review mechanisms of glucocorticoid sensitivity and resistance and highlight potential future directions to evaluate steroid responsiveness. Further research in this area will aid in optimizing steroid utilization and help determine when glucocorticoid therapy may no longer benefit patients.

Monocyte-Derived Dendritic Cells Differentiated in the Presence of Lenalidomide Display a Semi-Mature Phenotype, Enhanced Phagocytic Capacity, and Th1 Polarization Capability

Lenalidomide is an analog of thalidomide, with potent anticancer activity demonstrated in several hematological malignancies. It has immunomodulatory properties, being able to enhance the activation of different types of immune cells, which results in antitumor activities. Dendritic cells (DCs) are pivotal in the immune response, and different immunotherapeutic approaches targeting these cells are being developed. Since little is known about the effect of lenalidomide on DCs, the goal of the present work was to investigate the phenotype and function of human monocyte-derived DCs differentiated in the presence of lenalidomide (L-DCs). Our results showed that L-DCs display a unique phenotype, with increased cell surface expression of some maturation markers such as CD1d, CD83, CD86, and HLA-DR. This phenotype correlates with a lower expression of the E3 ubiquitin-ligase MARCH-I in L-DCs, upregulating the cell surface expression of CD86 and HLA-DR. In addition, immature L-DCs express higher amounts of DC-SIGN on the cell surface than control immature DCs. After LPS stimulation, production of IL-6 and TNF-α was severely decreased, whereas IL-12 and IL-10 secretion was dramatically upregulated in L-DCs, compared to that in the controls. Functionally, L-DCs are more effectively recognized by NKT cells in cytotoxicity experiments. Furthermore, L-DCs display higher opsonin-independent antigen uptake capability than control DCs. Mixed lymphocyte reaction experiments showed that L-DCs could stimulate naïve CD4 T-cells, polarizing them toward a predominant Th1 phenotype. In summary, DCs derived from monocytes in the presence of lenalidomide present a semi-mature phenotype, increased phagocytic capacity, reduced production of proinflammatory cytokines, and the ability to polarize T-cells toward predominant Th1-type responses; these are qualities that might be useful in the development of new immunotherapeutic treatments.

The novel compound STK405759 is a microtubule-targeting agent with potent and selective cytotoxicity against multiple myeloma in vitro and in vivo

Despite advances in treatment, multiple myeloma (MM) remains incurable. Here we propose the use of STK405759, a novel microtubule targeting agent (MTA) and member of the furan metotica family for MM therapy.

STK405759 inhibited tubulin polymerization in a cell-free system and in myeloma cells. This molecule had potent cytotoxic activity against several MM cell lines and patient-derived MM cells. Moreover, STK405759 demonstrated cytotoxicity against drug-resistant myeloma cells that overexpressed the P-glycoprotein drug-efflux pump. STK405759 was not cytotoxic to peripheral blood mononuclear cells, including activated B and T lymphocytes. This compound caused mitotic arrest and apoptosis of myeloma cells characterized by cleavage of poly (ADP-ribose) polymerase-1 and caspase-8, as well as decreased protein expression of mcl-1. The combination of STK405759 with bortezomib, lenalidomide or dexamethasone had synergistic cytotoxic activity. In in vivo studies, STK405759-treated mice had significantly decreased MM tumor burden and prolonged survival compared to vehicle treated- mice.

These results provide a rationale for further evaluation of STK405759 as monotherapy or part of combination therapy for treating patients with MM.

A novel 3D mesenchymal stem cell model of the multiple myeloma bone marrow niche: biologic and clinical applications

Specific niches within the tumor bone marrow (BM) microenvironment afford a sanctuary for multiple myeloma (MM) clones due to stromal cell-tumor cell interactions, which confer survival advantage and drug resistance. Defining the sequelae of tumor cell interactions within the MM niches on an individualized basis may provide the rationale for personalized therapies. To mimic the MM niche, we here describe a new 3D co-culture ex-vivo model in which primary MM patient BM cells are co-cultured with mesenchymal stem cells (MSC) in a hydrogel 3D system. In the 3D model, MSC with conserved phenotype (CD73+CD90+CD105+) formed compact clusters with active fibrous connections, and retained lineage differentiation capacity. Extracellular matrix molecules, integrins, and niche related molecules including N-cadherin and CXCL12 are expressed in 3D MSC model. Furthermore, activation of osteogenesis (MMP13, SPP1, ADAMTS4, and MGP genes) and osteoblastogenic differentiation was confirmed in 3D MSC model. Co-culture of patient-derived BM mononuclear cells with either autologous or allogeneic MSC in 3D model increased proliferation of MM cells, CXCR4 expression, and SP cells. We carried out immune profiling to show that distribution of immune cell subsets was similar in 3D and 2D MSC model systems. Importantly, resistance to novel agents (IMiDs, bortezomib, carfilzomib) and conventional agents (doxorubicin, dexamethasone, melphalan) was observed in 3D MSC system, reflective of clinical resistance. This 3D MSC model may therefore allow for studies of MM pathogenesis and drug resistance within the BM niche. Importantly, ongoing prospective trials are evaluating its utility to inform personalized targeted and immune therapy in MM.

Microenvironment drug resistance in multiple myeloma: emerging new players

Multiple myeloma (MM) drug resistance (DR) is a multistep transformation process based on a powerful interplay between bone marrow stromal cells and MM cells that allows the latter to escape anti-myeloma therapies. Here we present an overview of the role of the bone marrow microenvironment in both soluble factors-mediated drug resistance (SFM-DR) and cell adhesion-mediated drug resistance (CAM-DR), focusing on the role of new players, namely miRNAs, exosomes and cancer-associated fibroblasts.

Bone marrow stroma protects myeloma cells from cytotoxic damage via induction of the oncoprotein MUC1

Multiple myeloma (MM) is a lethal haematological malignancy that arises in the context of a tumour microenvironment that promotes resistance to apoptosis and immune escape. In the present study, we demonstrate that co-culture of MM cells with stromal cells results in increased resistance to cytotoxic and biological agents as manifested by decreased rates of cell death following exposure to alkylating agents and the proteosome inhibitor, bortezomib. To identify the mechanism of increased resistance, we examined the effect of the co-culture of MM cells with stroma cells, on expression of the MUC1 oncogene, known to confer tumour cells with resistance to apoptosis and necrosis. Co-culture of stroma with MM cells resulted in increased MUC1 expression by tumour cells. The effect of stromal cell co-culture on MUC1 expression was not dependent on cell contact and was therefore thought to be due to soluble factors secreted by the stromal cells into the microenvironment. We demonstrated that MUC1 expression was mediated by interleukin-6 and subsequent up-regulation of the JAK-STAT pathway. Interestingly, the effect of stromal cell co-culture on tumour resistance was partially reversed by silencing of MUC1 in MM cells, consistent with the potential role of MUC1 in mediating resistance to cytotoxic-based therapies.

CD200 Expression on Plasma Cell Myeloma Cells is Associated with the Efficacies of Bortezomib, Lenalidomide and Thalidomide

Plasma cell myeloma (PCM) is a devastating disease with a highly heterogeneous outcome, with survival ranging from a few months to longer than 10 years. Treatment of multiple myeloma has changed markedly in the past decade due to the development of new drugs such as bortezomib, lenalidomide and thalidomide, which have greatly improved the outcome of PCM. The clinical and prognostic value of immunophenotyping in PCM remains questionable. The aim of this study was to determine the diagnostic and prognostic significance of CD200 expression in newly diagnosed PCM. We retrospectively reviewed the records of 107 patients newly diagnosed with PCM at Showa University Hospital between January 2004 and September 2013. Expression of CD200 was studied by immunohistochemistry. Clinical and pathological parameters were compared between CD200-positive and CD200-negative cases. CD200-positive PCM cases had lower serum albumin (p = 0.0001) compared to those without CD200 expression. Our results showed no significant difference in median overall survival between patients with CD200-positive and CD200-negative PCM. However, there was a strong correlation between CD200 expression and serum albumin level. In the CD200-negative group, median overall survival was significantly longer in patients who received new drug treatment. These findings suggest that CD200 expression is a useful marker for evaluation of the severity of PCM and that lack of CD200 expression may improve the sensitivity of PCM to therapy with new drugs.

Molecular and clinical significance of fibroblast growth factor 2 (FGF2 /bFGF) in malignancies of solid and hematological cancers for personalized therapies

Fibroblast growth factor (FGF) signaling is essential for normal and cancer biology. Mammalian FGF family members participate in multiple signaling pathways by binding to heparan sulfate and FGF receptors (FGFR) with varying affinities. FGF2 is the prototype member of the FGF family and interacts with its receptor to mediate receptor dimerization, phosphorylation, and activation of signaling pathways, such as Ras-MAPK and PI3K pathways. Excessive mitogenic signaling through the FGF/FGFR axis may induce carcinogenic effects by promoting cancer progression and increasing the angiogenic potential, which can lead to metastatic tumor phenotypes. Dysregulated FGF/FGFR signaling is associated with aggressive cancer phenotypes, enhanced chemotherapy resistance and poor clinical outcomes. In vitro experimental settings have indicated that extracellular FGF2 affects proliferation, drug sensitivity, and apoptosis of cancer cells. Therapeutically targeting FGF2 and FGFR has been extensively assessed in multiple preclinical studies and numerous drugs and treatment options have been tested in clinical trials. Diagnostic assays are used to quantify FGF2, FGFRs, and downstream signaling molecules to better select a target patient population for higher efficacy of cancer therapies. This review focuses on the prognostic significance of FGF2 in cancer with emphasis on therapeutic intervention strategies for solid and hematological malignancies.

Effects of IL-8 Up-Regulation on Cell Survival and Osteoclastogenesis in Multiple Myeloma

IL-8 promotes cancer cell growth, survival, angiogenesis, and metastasis in several tumors. Herein, we investigated the sources of IL-8 production in multiple myeloma (MM) and its potential roles in MM pathogenesis. We found that bone marrow cells from patients with MM secreted higher amounts of IL-8 than healthy donors. IL-8 production was detected in cultures of CD138(+) plasma cells and CD138(-) cells isolated from bone marrows of MM patients, and in three of seven human myeloma cell lines (HMCLs) analyzed. Interactions between MM and stromal cells increased IL-8 secretion by stromal cells through cell-cell adhesion and soluble factors. Interestingly, IL8 expression also increased in HMCLs, stromal cells, and osteoclasts after treatment with the antimyeloma drugs melphalan and bortezomib. In fact, the effect of bortezomib on IL-8 production was higher than that exerted by stromal-MM cell interactions. Addition of exogenous IL-8 did not affect growth of HMCLs, although it protected cells from death induced by serum starvation through a caspase-independent mechanism. Furthermore, IL-8 induced by stromal-MM cell interactions strongly contributed to osteoclast formation in vitro, because osteoclastogenesis was markedly reduced by IL-8-specific neutralizing antibodies. In conclusion, our results implicate IL-8 in myeloma bone disease and point to the potential utility of an anti-IL-8 therapy to prevent unwanted effects of IL-8 up-regulation on survival, angiogenesis, and osteolysis in MM.

Siltuximab (CNTO 328) with lenalidomide, bortezomib and dexamethasone in newly-diagnosed, previously untreated multiple myeloma: an open-label phase I trial

The safety and efficacy of siltuximab (CNTO 328) was tested in combination with lenalidomide, bortezomib and dexamethasone (RVD) in patients with newly-diagnosed, previously untreated symptomatic multiple myeloma. Fourteen patients were enrolled in the study, eleven of whom qualified to receive therapy. A majority of patients (81.8%) completed the minimal number or more of the four required cycles, while two patients completed only three cycles. The maximum tolerated dose (MTD) of siltuximab with RVD was dose level -1 (siltuximab: 8.3 mg/kg; bortezomib: 1.3 mg/m(2); lenalidomide: 25 mg; dexamethasone: 20 mg). Serious adverse events were grade 3 pneumonia and grade 4 thrombocytopenia, and no deaths occurred during the study or with follow-up (median follow-up 28.1 months). An overall response rate, after 3-4 cycles of therapy, of 90.9% (95% confidence interval (CI): 58.7%, 99.8%) (9.1% complete response (95% CI: 0.2%, 41.3%), 45.5% very good partial response (95% CI: 16.7%, 76.6%) and 36.4% partial response (95% CI: 10.9%, 69.2%)) was seen. Two patients withdrew consent, and nine patients (81.8%) opted for autologous stem cell transplantation.

Mechanisms of Drug Resistance in Relapse and Refractory Multiple Myeloma

Multiple myeloma (MM) is a hematological malignancy that remains incurable because most patients eventually relapse or become refractory to current treatments. Although the treatments have improved, the major problem in MM is resistance to therapy. Clonal evolution of MM cells and bone marrow microenvironment changes contribute to drug resistance. Some mechanisms affect both MM cells and microenvironment, including the up- and downregulation of microRNAs and programmed death factor 1 (PD-1)/PD-L1 interaction. Here, we review the pathogenesis of MM cells and bone marrow microenvironment and highlight possible drug resistance mechanisms. We also review a potential molecular targeting treatment and immunotherapy for patients with refractory or relapse MM.

Environmental immune disruptors, inflammation and cancer risk

An emerging area in environmental toxicology is the role that chemicals and chemical mixtures have on the cells of the human immune system. This is an important area of research that has been most widely pursued in relation to autoimmune diseases and allergy/asthma as opposed to cancer causation. This is despite the well-recognized role that innate and adaptive immunity play as essential factors in tumorigenesis. Here, we review the role that the innate immune cells of inflammatory responses play in tumorigenesis. Focus is placed on the molecules and pathways that have been mechanistically linked with tumor-associated inflammation. Within the context of chemically induced disturbances in immune function as co-factors in carcinogenesis, the evidence linking environmental toxicant exposures with perturbation in the balance between pro- and anti-inflammatory responses is reviewed. Reported effects of bisphenol A, atrazine, phthalates and other common toxicants on molecular and cellular targets involved in tumor-associated inflammation (e.g. cyclooxygenase/prostaglandin E2, nuclear factor kappa B, nitric oxide synthesis, cytokines and chemokines) are presented as example chemically mediated target molecule perturbations relevant to cancer. Commentary on areas of additional research including the need for innovation and integration of systems biology approaches to the study of environmental exposures and cancer causation are presented.

IL10 receptor is a novel therapeutic target in DLBCLs

Diffuse large B-cell lymphoma (DLBCL) is a biologically and clinically heterogeneous disease with marked genomic instability and variable response to conventional R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone) chemotherapy. More clinically aggressive cases of DLBCLs have high level of circulating interleukin 10 (IL10) cytokine and evidence of activated intracellular STAT3 (signal transducer and activator of transcription 3) signaling. We investigated the role of IL10 and its surface receptor in supporting the neoplastic phenotype of DLBCLs. We determined that IL10RA gene is amplified in 21% and IL10RB gene in 10% of primary DLBCLs. Gene expression of IL10, IL10RA and IL10RB was markedly elevated in DLBCLs. We hypothesized that DLBCLs depend for their proliferation and survival on IL10-STAT3 signaling and that blocking the IL10 receptor (IL10R) would induce cell death. We used anti-IL10R blocking antibody, which resulted in a dose-dependent cell death in all tested activated B-cell-like subtype of DLBCL cell lines and primary DLBCLs. Response of germinal center B-cell-like subtype of DLBCL cell lines to anti-IL10R antibody varied from sensitive to resistant. Cells underwent cell cycle arrest, followed by induction of apoptosis. Cell death depended on inhibition of STAT3 and, to a lesser extent, STAT1 signaling. Anti-IL10R treatment resulted in interruption of IL10-IL10R autostimulatory loop. We thus propose that IL10R is a novel therapeutic target in DLBCLs.

Phase 1 study in Japan of siltuximab, an anti-IL-6 monoclonal antibody, in relapsed/refractory multiple myeloma

Siltuximab, a chimeric monoclonal antibody with high affinity and specificity for interleukin-6, has been shown to enhance anti-multiple myeloma activity of bortezomib and corticosteroid in vitro. We evaluated the safety, pharmacokinetics, immunogenicity, and antitumor effect of siltuximab in combination with bortezomib and dexamethasone in Japanese patients with relapsed or refractory multiple myeloma. This open-label, phase 1, dose-escalating study used two doses of siltuximab: 5.5 and 11.0 mg/kg (administered on day 1 of each 21-day cycle). In total, nine patients were treated. The most common grade 3/4 adverse events, lymphopenia (89 %) and thrombocytopenia (44 %), occurred in patients receiving both doses of siltuximab; however, no dose-limiting toxicities (DLTs) were observed. Following intravenous administration of siltuximab at 5.5 and 11.0 mg/kg, the maximum serum concentration and the area under the curve from 0 to 21 days and from 0 to infinity increased in an approximately dose-proportional manner. Mean half-life, total systemic clearance, and volume of distribution were similar at doses of 5.5 and 11.0 mg/kg. Across both doses, six of the nine patients had complete or partial response (22 and 44 %, respectively). In conclusion, as no DLT was observed, the recommended dose for this combination is 11.0 mg/kg once every 3 weeks. The study is registered at http://www.clinicaltrials.gov as NCT01309412.

The tumor microenvironment shapes hallmarks of mature B-cell malignancies

B-cell tumorigenesis results from a host of known and unknown genetic anomalies, including non-random translocations of genes that normally function as determinants of cell proliferation or cell survival to regions juxtaposed to active immunoglobulin heavy chain enhancer elements, chromosomal aneuploidy, somatic mutations that further affect oncogenic signaling and loss of heterozygosity of tumor-suppressor genes. However, it is critical to recognize that even in the setting of a genetic disease, the B-cell/plasma cell tumor microenvironment (TME) contributes significantly to malignant transformation and pathogenesis. Over a decade ago, we proposed the concept of cell adhesion-mediated drug resistance to delineate a form of TME-mediated drug resistance that protects hematopoietic tumor cells from the initial effect of diverse therapies. In the interim, it has been increasingly appreciated that TME also contributes to tumor initiation and progression through sustained growth/proliferation, self-renewal capacity, immune evasion, migration and invasion as well as resistance to cell death in a host of B-cell malignancies, including mantle cell lymphoma, diffuse large B-cell lymphoma, Waldenstroms macroglobulinemia, chronic lymphocytic leukemia and multiple myeloma. Within this review, we propose that TME and the tumor co-evolve as a consequence of bidirectional signaling networks. As such, TME represents an important target and should be considered integral to tumor progression and drug response.

Drug resistance in multiple myeloma: latest findings and new concepts on molecular mechanisms

In the era of new and mostly effective therapeutic protocols, multiple myeloma still tends to be a hard-to-treat hematologic cancer. This hallmark of the disease is in fact a sequel to drug resistant phenotypes persisting initially or emerging in the course of treatment. Furthermore, the heterogeneous nature of multiple myeloma makes treating patients with the same drug challenging because finding a drugable oncogenic process common to all patients is not yet feasible, while our current knowledge of genetic/epigenetic basis of multiple myeloma pathogenesis is outstanding. Nonetheless, bone marrow microenvironment components are well known as playing critical roles in myeloma tumor cell survival and environment-mediated drug resistance happening most possibly in all myeloma patients. Generally speaking, however; real mechanisms underlying drug resistance in multiple myeloma are not completely understood. The present review will discuss the latest findings and concepts in this regard. It reviews the association of important chromosomal translocations, oncogenes (e.g. TP53) mutations and deranged signaling pathways (e.g. NFκB) with drug response in clinical and experimental investigations. It will also highlight how bone marrow microenvironment signals (Wnt, Notch) and myeloma cancer stem cells could contribute to drug resistance in multiple myeloma.

Sheet-type titania, but not P25, induced paraptosis accompanying apoptosis in murine alveolar macrophage cells

In this study, we identified the toxic effects of sheet-type titania (TNS), which are being developed as a material for UV-blocking glass, comparing with P25, a benchmark control for titania, in MH-S cells, a mouse alveolar macrophage cell line. After 24 h exposure, the TNS-exposed cells formed large vacuoles while the P25-exposed ones did not. The decreased levels of cell viability were similar between the P25 and TNS groups, but ATP production was clearly lower in cells exposed to the TNS. P25 decreased the expression of calnexin protein, an endoplasmic reticulum (ER) membrane marker, and increased the number of cells generating ROS in a dose dependent manner. Meanwhile, TNS dilated the ER and mitochondria and increased the secretion of NO and pro-inflammatory cytokines, but not of ROS. Subsequently, we studied the molecular response following TNS-induced vacuolization. TNS started to form vacuoles in the cytosol since 20 min after exposure, and the expression of the mitochondria function-related genes were down-regulated the most in the cells exposed for 1 h. After 24 h exposure, the number of apoptotic cells and the relative levels of BAX to Bcl-2 increased. The expression of SOD1 protein, but not of SOD2, also dose-dependently increased with an increase in caspase-8 activity. Additionally, the MAPK pathway was significantly activated, even though the expression of p-EGFR did not change significantly. Furthermore, the number of apoptotic cells increased rapidly with time and with the inhibition of vacuole formation. Taken together, we suggest that P25 and TNS may target different organelles. In addition, TNS, but not P25, induced paraptosis accompanied by apoptosis in MH-S cells, and the formation of the cytoplasmic vacuoles allowed delay apoptosis following TNS exposure.

Preclinical validation of interleukin 6 as a therapeutic target in multiple myeloma

Studies on the biologic and molecular genetic underpinnings of multiple myeloma (MM) have identified the pleiotropic, pro-inflammatory cytokine, interleukin-6 (IL-6), as a factor crucial to the growth, proliferation and survival of myeloma cells. IL-6 is also a potent stimulator of osteoclastogenesis and a sculptor of the tumor microenvironment in the bone marrow of patients with myeloma. This knowledge has engendered considerable interest in targeting IL-6 for therapeutic purposes, using a variety of antibody- and small-molecule-based therapies. However, despite the early recognition of the importance of IL-6 for myeloma and the steady progress in our knowledge of IL-6 in normal and malignant development of plasma cells, additional efforts will be required to translate the promise of IL-6 as a target for new myeloma therapies into significant clinical benefits for patients with myeloma. This review summarizes published research on the role of IL-6 in myeloma development and describes ongoing efforts by the University of Iowa Myeloma Multidisciplinary Oncology Group to develop new approaches to the design and testing of IL-6-targeted therapies and preventions of MM.

Clarithromycin overcomes resistance to lenalidomide and dexamethasone in multiple myeloma

The combination of clarithromycin, lenalidomide and dexamethasone (BiRd) has led to highly durable responses in newly diagnosed myeloma. However, the ability of clarithromycin to overcome resistance to lenalidomide and dexamethasone (Rd) is not known. To study this, we performed a retrospective analysis of 24 patients with myeloma for which clarithromycin was added to Rd at the time of progression on Rd. The median number of prior therapies was 3 (range 1-8). The best response was complete response (CR) in one (4.2%), very good partial response (VGPR) in one (4.2%) and partial response in eight (33.3%) patients. Ten patients, 41.7% (95% CI: 22.1, 63.4), achieved ≥PR. The median time to response was 4.4 months (range 1-13.6 months) and the median duration of response was 6.9 months (range 3-52.2 months). The clinical benefit rate (CR + VGPR + PR + MR) was 45.8% (95% CI 25.6, 67.2). The median progression-free survival was 4 months. Median overall survival was 25 months with a median follow-up of 27.5 months. The regimen was well tolerated and only 2 patients needed a clarithromycin dose reduction. Addition of clarithromycin to Rd can overcome resistance to Rd in a subset of patients and lead to durable clinical responses.

Trial Watch: Lenalidomide-based immunochemotherapy

Lenalidomide is a synthetic derivative of thalidomide currently approved by the US Food and Drug Administration for use in patients affected by multiple myeloma (in combination with dexamethasone) and low or intermediate-1 risk myelodysplastic syndromes that harbor 5q cytogenetic abnormalities. For illustrative purposes, the mechanism of action of lenalidomide can be subdivided into a cancer cell-intrinsic, a stromal, and an immunological component. Indeed, lenalidomide not only exerts direct cell cycle-arresting and pro-apoptotic effects on malignant cells, but also interferes with their physical and functional interaction with the tumor microenvironment and mediates a robust, pleiotropic immunostimulatory activity. In particular, lenalidomide has been shown to stimulate the cytotoxic functions of T lymphocytes and natural killer cells, to limit the immunosuppressive impact of regulatory T cells, and to modulate the secretion of a wide range of cytokines, including tumor necrosis factor α, interferon γ as well as interleukin (IL)-6, IL-10, and IL-12. Throughout the last decade, the antineoplastic and immunostimulatory potential of lenalidomide has been investigated in patients affected by a wide variety of hematological and solid malignancies. Here, we discuss the results of these studies and review the status of clinical trials currently assessing the safety and efficacy of this potent immunomodulatory drug in oncological indications.

Thyrotropin regulates IL-6 expression in CD34+ fibrocytes: clear delineation of its cAMP-independent actions

IL-6 plays diverse roles in normal and disease-associated immunity such as that associated with Graves’ disease (GD). In that syndrome, the orbit undergoes remodeling during a process known as thyroid-associated ophthalmopathy (TAO). Recently, CD34⁺ fibrocytes were found to infiltrate the orbit in TAO where they transition into CD34⁺ orbital fibroblasts. Surprisingly, fibrocytes display high levels of functional thyrotropin receptor (TSHR), the central antigen in GD. We report here that TSH and the pathogenic anti-TSHR antibodies that drive hyperthyroidism in GD induce IL-6 expression in fibrocytes and orbital fibroblasts. Unlike TSHR signaling in thyroid epithelium, that occurring in fibrocytes is completely independent of adenylate cyclase activation and cAMP generation. Instead TSH activates PDK1 and both AKT/PKB and PKC pathways. Expression and use of PKCβII switches to that of PKCµ as fibrocytes transition to TAO orbital fibroblasts. This shift is imposed by CD34⁻ orbital fibroblasts but reverts when CD34⁺ fibroblasts are isolated. The up-regulation of IL-6 by TSH results from coordinately enhanced IL-6 gene promoter activity and increased IL-6 mRNA stability. TSH-dependent IL-6 expression requires activity at both CREB (−213 to −208 nt) and NF-κB (–78 to −62 nt) binding sites. These results provide novel insights into the molecular action of TSH and signaling downstream for TSHR in non-thyroid cells. Fibrocytes neither express adenylate cyclase nor generate cAMP and thus these findings are free from any influence of cAMP-related signaling. They identify potential therapeutic targets for TAO.

The B-cell receptor orchestrates environment-mediated lymphoma survival and drug resistance in B-cell malignancies

Specific niches within the lymphoma tumor microenvironment (TME) provide sanctuary for subpopulations of tumor cells through stromal cell-tumor cell interactions. These interactions notably dictate growth, response to therapy and resistance of residual malignant B cells to therapeutic agents. This minimal residual disease (MRD) remains a major challenge in the treatment of B-cell malignancies and contributes to subsequent disease relapse. B-cell receptor (BCR) signaling has emerged as essential mediator of B-cell homing, survival and environment-mediated drug resistance (EMDR). Central to EMDR are chemokine- and integrin-mediated interactions between lymphoma and the TME. Further, stromal cell-B cell adhesion confers a sustained BCR signaling leading to chemokine and integrin activation. Recently, the inhibitors of BCR signaling have garnered a substantial clinical interest because of their effectiveness in B-cell disorders. The efficacy of these agents is, at least in part, attributed to attenuation of BCR-dependent lymphoma-TME interactions. In this review, we discuss the pivotal role of BCR signaling in the integration of intrinsic and extrinsic determinants of TME-mediated lymphoma survival and drug resistance.

Multiple myeloma staging based on the combination of beta-2-microglobulin and albumin: The role of albumin in the model

BACKGROUND AND OBJECTIVE

Since the prognostic significance of the combination of beta-2-microglobulin (beta(2)m) and albumin in multiple myeloma (MM) has been recognized, these two easily obtainable parameters were subsequently employed in the staging systems of Bataille et al. (BSS), the South West Oncology Group (SWOG SS) and most recently the International Myeloma Working Group (ISS). There is no consensus, however, regarding the cut off levels of beta(2)m and the stage, early or advanced, at which albumin should be added to the model. At the same time, Weber et al. demonstrated similar results using beta(2)m alone in identical cut-offs with ISS (WSS). The aim of the present study is to apply these four staging systems in 504 MM patients, in order to discern the role of albumin in MM staging and evaluate if, and at which stage, albumin should be added to the model.

METHODS

Median overall survival (OS) according to BSS, SWOG SS, ISS and WSS was estimated according to the Kaplan-Meier method. OS differences between the stages were assessed using the log-rank test. Patients with beta(2)m < 3.5 mg/l and albumin < 3.5 g/dl, who were classified in stage II according to ISS and in stage I according to WSS, were analyzed separately in order to detect in which prognostic group they practically belong.

RESULTS

BSS and SWOG SS failed to distinguish stage II from stage III patients and stage III from stage IV patients, respectively. ISS and WSS achieved clear stratification of the patients into three distinct prognostic subgroups, but WSS I patients had a lower life expectancy than ISS I patients. This difference was due to false inclusion of patients with beta(2)m < 3.5 mg/l and albumin < 3.5 g/dl in stage I by WSS, while separate analysis of these patients proved that they belong, in fact, in stage II. In an attempt to improve its prognostic impact, WSS was then successfully modified by dividing WSS I patients in two substages, WSS IA: beta(2)m < 2.5 mg/l and WSS IB: 2.5 mg/l < or = beta(2)m < 3.5 mg/l, thus designating a low-risk and a low-intermediate-risk subgroup, respectively.

CONCLUSION

Albumin appears to lose its prognostic value at high cut-off levels of beta(2)m, while it enhances the prognostic significance of beta(2)m at low cut-off levels of the latter. Albumin cannot be eliminated from the ISS, since it is absolutely necessary in order to identify true low-risk patients. The only possibility for albumin exclusion from the model, could be to decrease the beta(2)m low-risk cut-off from 3.5 to 2.5 mg/l.

Zoledronic acid exerts its antitumor effect in multiple myeloma interfering with the bone marrow microenvironment

Multiple myeloma (MM) is a B-cell malignancy characterized by an excess of monotypic plasma cells which localize almost exclusively in the bone marrow provoking bone destruction via the activation of the osteoclasts. The bone marrow microenvironment, mainly through stromal cells, is strictly involved in the evolution of the disease supporting MM cell growth and survival [1]. MM plasma cells reside in the bone marrow by binding to adhesion molecule of extracellular matrix (ECM) and stromal cells. The activation of some signaling pathways within the stromal cells increases the production of several cytokines which in turn favors the myeloma cell proliferation and survival [2-6], and enhance the drug resistance by anti-apoptotic mechanisms [1,7-9]. Novel therapeutic agents target not only the myeloma cells but also the interaction between MM cells and the bone marrow microenvironment [8]. Bisphosphonates (Bps) interfere as well with bone microenvironment inhibiting the survival of stromal cells and hampering the contact between plasma and stromal cells. In this review we will revise preclinical evidences, and the potential mechanisms of the antitumor activity of zoledronic acid.

A phase 2 multicentre study of siltuximab, an anti-interleukin-6 monoclonal antibody, in patients with relapsed or refractory multiple myeloma

Interleukin-6 (IL6) plays a central role in multiple myeloma pathogenesis and confers resistance to corticosteroid-induced apoptosis. We therefore evaluated the efficacy and safety of siltuximab, an anti-IL6 monoclonal antibody, alone and in combination with dexamethasone, for patients with relapsed or refractory multiple myeloma who had ≥ 2 prior lines of therapy, one of which had to be bortezomib-based. Fourteen initial patients received siltuximab alone, 10 of whom had dexamethasone added for suboptimal response; 39 subsequent patients were treated with concurrent siltuximab and dexamethasone. Patients received a median of four prior lines of therapy, 83% were relapsed and refractory, and 70% refractory to their last dexamethasone-containing regimen. Suppression of serum C-reactive protein levels, a surrogate marker of IL6 inhibition, was demonstrated. There were no responses to siltuximab but combination therapy yielded a partial (17%) + minimal (6%) response rate of 23%, with responses seen in dexamethasone-refractory disease. The median time to progression, progression-free survival and overall survival for combination therapy was 4.4, 3.7 and 20.4 months respectively. Haematological toxicity was common but manageable. Infections occurred in 57% of combination-treated patients, including ≥ grade 3 infections in 18%. Further study of siltuximab in modern corticosteroid-containing myeloma regimens is warranted, with special attention to infection-related toxicity.

The emerging role of lenalidomide in the management of lymphoid malignancies

Lenalidomide, a novel immunomodulatory drug (IMiD), is a promising therapeutic strategy for patients with relapsed/refractory chronic lymphocytic leukemia (CLL) and B-cell lymphomas. Biologically, the mechanisms responsible for lenalidomide activity are yet to be clearly defined. Based on preclinical models and early correlative studies conducted in parallel to clinical trials, lenalidomide has been found to enhance natural killer (NK)- and T-cell activity against tumor cells, alter the balance of pro- and anti-inflammatory cytokines in the tumor bed, inhibit angiogenesis, and, to a lesser degree, induce cell cycle arrest and apoptosis in cancer cells. Together, all of these biological effects appear to play a role in the activity observed in CLL or lymphoma patients treated with lenalidomide. Given the effect in NK- and T-cell function, lenalidomide is an alternative strategy to enhance the antitumor activity of monoclonal antibodies (mAbs). Clinical responses have been observed in patients with relapsed/refractory CLL, follicular lymphoma, small lymphocytic lymphoma, mantle cell lymphoma (MCL), and diffuse large B-cell lymphoma (DLBCL) treated with lenalidomide single agent. The favorable toxicity profile and route of administration made the use of lenalidomide an attractive therapy for certain types of patients (i.e. elderly, chemotherapy unfit, etc.). The erratic but serious incidence of tumor lysis syndrome and/or tumor flare reactions provides challenges in the incorporation of lenalidomide in the management of previously untreated CLL or CLL/lymphoma patients with bulky adenopathy. Correlative studies and/or retrospective analysis of lenalidomide-treated patients had identified several biomarkers associated with clinical endpoints in CLL (i.e. changes in tumor necrosis factor alpha [TNF-α] or vascular endothelial growth factor [VEGF] levels) or DLBCL (non-GCB phenotype) patients, but need to be validated. Early studies evaluating the efficacy and toxicity of lenalidomide in combination with rituximab in previously untreated indolent lymphoma are promising and warrant further study. In addition, the evaluation of lenalidomide in the maintenance setting or in combination with other target-specific agents (i.e. proteasome inhibitors) in aggressive lymphomas is being addressed in ongoing clinical trials. In summary, lenalidomide is emerging as a biologically active and novel agent in the treatment of B-cell neoplasms. Future translational and clinical studies will further define the role of lenalidomide in the management of de novo or relapsed/refractory CLL or B-cell lymphomas and identify the subset of patients most likely to gain clinical benefit.

Molecular action of lenalidomide in lymphocytes and hematologic malignancies

The immunomodulatory agent, lenalidomide, is a structural analogue of thalidomide approved by the US Food and Drug Administration for the treatment of myelodysplastic syndrome (MDS) and multiple myeloma (MM). This agent is also currently under active investigation for the treatment of chronic lymphocytic leukemia (CLL) and non-Hodgkin's lymphoma (NHL), as well as in drug combinations for some solid tumors and mantle cell lymphoma (MCL). Although treatment with lenalidomide has translated into a significant extension in overall survival in MM and MDS and has superior safety and efficacy relative to thalidomide, the mechanism of action as it relates to immune modulation remains elusive. Based on preclinical models and clinical trials, lenalidomide, as well as other structural thalidomide derivatives, enhances the proliferative and functional capacity of T-lymphocytes and amplifies costimulatory signaling pathways that activate effector responses and suppress inflammation. This paper summarizes our current understanding of T- and natural killer (NK) cell pathways that are modified by lenalidomide in hematopoietic neoplasms to inform future decisions about potential combination therapies.

CD40 stimulation induces vincristine resistance via AKT activation and MRP1 expression in a human multiple myeloma cell line

Various co-stimulatory receptors are expressed in multiple myeloma (MM) both in immune microenvironment and in the tumor microenvironment in vivo. In relapsed human MM, these receptors are known to increase cell proliferation and induce conventional drug resistance. However, the mechanism of drug resistance induced via co-stimulatory receptors is poorly understood. In this study, we examined the role of CD40 expressed on MM cell lines. Out of all of the KMS MM cell lines, the KMS28BM cells expressed high levels of the CD40 receptor. When stimulated with anti-CD40 antibody or recombinant human CD40L, the proliferation of KMS28BM cells was increased 1.7 fold. In CD40-stimulated KMS28BM cells, signaling via the AKT pathway caused an increase in the expression of multidrug resistance-associated gene 1 (MRP1) and IL-6 by 2.2 fold and 30 fold, respectively, but not the MDR1 gene. Furthermore, CD40-stimulated KMS28BM cells were observed to be substantially resistant to the anticancer drug vincristine, and when cells were treated with the MRP1 specific inhibitor, MK-571, drug resistance was decreased. We also found that CD40-stimulated, MRP1-expressing KMS28BM cells significantly increased calcein efflux, and calcein efflux was inhibited through treatment with MK-571. Therefore, blocking CD40 and inhibiting MRP1 are potential targets to treat CD40-induced drug resistance in multiple myeloma.

CD28 expressed on malignant plasma cells induces a prosurvival and immunosuppressive microenvironment

Interactions between the malignant plasma cells of multiple myeloma and stromal cells within the bone marrow microenvironment are essential for myeloma cell survival, mirroring the same dependence of normal bone marrow-resident long-lived plasma cells on specific marrow niches. These interactions directly transduce prosurvival signals to the myeloma cells and also induce niche production of supportive soluble factors. However, despite their central importance, the specific molecular and cellular components involved remain poorly characterized. We now report that the prototypic T cell costimulatory receptor CD28 is overexpressed on myeloma cells during disease progression and in the poor-prognosis subgroups and plays a previously unrecognized role as a two-way molecular bridge to support myeloid stromal cells in the microenvironment. Engagement by CD28 to its ligand CD80/CD86 on stromal dendritic cell directly transduces a prosurvival signal to myeloma cell, protecting it against chemotherapy and growth factor withdrawal-induced death. Simultaneously, CD28-mediated ligation of CD80/CD86 induces the stromal dendritic cell to produce the prosurvival cytokine IL-6 (involving novel cross-talk with the Notch pathway) and the immunosuppressive enzyme IDO. These findings identify CD28 and CD80/CD86 as important molecular components of the interaction between myeloma cells and the bone marrow microenvironment, point to similar interaction for normal plasma cells, and suggest novel therapeutic strategies to target malignant and pathogenic (e.g., in allergy and autoimmunity) plasma cells.

Lenalidomide: a synthetic compound with an evolving role in cancer management

Lenalidomide is a functional and structural analogue of thalidomide with a relatively benign toxicity profile and pleiotropic anti-tumor activity, exhibiting anti-angiogenic and immunomodulatory effects. Lenalidomide has already been approved for the management of low or intermediate-1 risk myelodysplastic syndrome with chromosome 5q31 deletion and relapsed/refractory multiple myeloma in combination with dexamethasone. During the last five years, multiple clinical trials have been conducted to explore its potential efficacy in hematologic as well as in solid malignancies, revealing a significant benefit in clinical outcomes. This review outlines the mechanisms of action, the toxicity profile and the efficacy of lenalidomide, reviewing the current literature and focusing on the current status of the compound in cancer management. The determination of molecular biomarkers, predictive of clinical response to lenalidomide may reveal a more substantial role of this agent in the treatment of hematologic as well as solid malignancies.