Antibody-Dependent Cellular Phagocytosis by Macrophages is a Novel Mechanism of Action of Elotuzumab.

Elotuzumab, a recently approved antibody for the treatment of multiple myeloma, has been shown to stimulate Fcγ receptor (FcγR)-mediated antibody-dependent cellular cytotoxicity by natural killer (NK) cells toward myeloma cells. The modulatory effects of elotuzumab on other effector cells in the tumor microenvironment, however, has not been fully explored. Antibody-dependent cellular phagocytosis (ADCP) is a mechanism by which macrophages contribute to antitumor potency of monoclonal antibodies. Herein, we studied the NK cell independent effect of elotuzumab on tumor-associated macrophages using a xenograft tumor model deficient in NK and adaptive immune cells. We demonstrate significant antitumor efficacy of single-agent elotuzumab in immunocompromised xenograft models of multiple myeloma, which is in part mediated by Fc-FcγR interaction of elotuzumab with macrophages. Elotuzumab is shown in this study to induce phenotypic activation of macrophages in vivo and mediates ADCP of myeloma cells though a FcγR-dependent manner in vitro Together, these findings propose a novel immune-mediated mechanism by which elotuzumab exerts anti-myeloma activity and helps to provide rationale for combination therapies that can enhance macrophage activity. Mol Cancer Ther; 17(7); 1454-63. ©2018 AACR.

Inhibiting the oncogenic translation program is an effective therapeutic strategy in multiple myeloma.

Multiple myeloma (MM) is a frequently incurable hematological cancer in which overactivity of MYC plays a central role, notably through up-regulation of ribosome biogenesis and translation. To better understand the oncogenic program driven by MYC and investigate its potential as a therapeutic target, we screened a chemically diverse small-molecule library for anti-MM activity. The most potent hits identified were rocaglate scaffold inhibitors of translation initiation. Expression profiling of MM cells revealed reversion of the oncogenic MYC-driven transcriptional program by CMLD010509, the most promising rocaglate. Proteome-wide reversion correlated with selective depletion of short-lived proteins that are key to MM growth and survival, most notably MYC, MDM2, CCND1, MAF, and MCL-1. The efficacy of CMLD010509 in mouse models of MM confirmed the therapeutic relevance of these findings in vivo and supports the feasibility of targeting the oncogenic MYC-driven translation program in MM with rocaglates.

Prognostic role of circulating exosomal miRNAs in multiple myeloma.

Exosomes, secreted by several cell types, including cancer cells, can be isolated from the peripheral blood and have been shown to be powerful markers of disease progression in cancer. In this study, we examined the prognostic significance of circulating exosomal microRNAs (miRNAs) in multiple myeloma (MM). A cohort of 156 patients with newly diagnosed MM, uniformly treated and followed, was studied. Circulating exosomal miRNAs were isolated and used to perform a small RNA sequencing analysis on 10 samples and a quantitative reverse transcription polymerase chain reaction (qRT-PCR) array on 156 samples. We studied the relationship between miRNA levels and patient outcomes, including progression-free survival (PFS) and overall survival (OS). We identified miRNAs as the most predominant small RNAs present in exosomes isolated from the serum of patients with MM and healthy controls by small RNA sequencing of circulating exosomes. We then analyzed exosomes isolated from serum samples of 156 patients using a qRT-PCR array for 22 miRNAs. Two of these miRNAs, let-7b and miR-18a, were significantly associated with both PFS and OS in the univariate analysis and were still statistically significant after adjusting for the International Staging System and adverse cytogenetics in the multivariate analysis. Our findings support the use of circulating exosomal miRNAs to improve the identification of patients with newly diagnosed MM with poor outcomes. The results require further validation in other independent prospective MM cohorts.

Epigenetics in Multiple Myeloma.

Multiple myeloma is characterized by clonal proliferation of plasma cells within the bone marrow resulting in anemia, lytic bone lesions, hypercalcemia, and renal impairment. Despite advanced in our understanding of this complex disease in recent years, it is still considered an incurable malignancy. This is, in part, due to the highly heterogenous genomic and phenotypic nature of the disease, which is to date incompletely understood. It is clear that a deeper level of knowledge of the biological events underlying the development of these diseases is needed to identify new targets and generate effective novel therapies. MicroRNAs (miRNAs), which are single strand, 20-nucleotide, noncoding RNA's, are key regulators of gene expression and have been reported to exert transcriptional control in multiple myeloma. miRNAs are now recognized to play a role in many key areas such as cellular proliferation, differentiation, apoptosis and stress response. Substantial advances have been made in recent years in terms of our understanding of the biological role of miRNAs in a diverse range of hematological and solid malignancues, In multiple myeloma these advances have yielded new information of prognostic and diagnostic relevance which have helped to shed light on epigenetic regulation in this disease.

Genomic Aberrations in Multiple Myeloma.

Multiple myeloma (MM) is a genetically complex disease. The past few years have seen an evolution in cancer research with the emergence of next-generation sequencing (NGS), enabling high throughput sequencing of tumors-including whole exome, whole genome, RNA, and single-cell sequencing as well as genome-wide association study (GWAS). A few inherited variants have been described, counting for some cases of familial disease. Hierarchically, primary events in MM can be divided into hyperdiploid (HDR) and nonhyperdiploid subtypes. HRD tumors are characterized by trisomy of chromosomes 3, 5, 7, 9, 11, 15, 19, and/or 21. Non-HRD tumors harbor IGH translocations, mainly t(4;14), t(6;14), t(11;14), t(14;16), and t(14;20). Secondary events participate to the tumor progression and consist in secondary translocation involving MYC, copy number variations (CNV) and somatic mutations (such as mutations in KRAS, NRAS, BRAF, P53). Moreover, the dissection of clonal heterogeneity helps to understand the evolution of the disease. The following review provides a comprehensive review of the genomic landscape in MM.

Monoclonal gammopathy: The good, the bad and the ugly.

Monoclonal gammopathy of undetermined significance (MGUS) is a condition characterized by the presence of a monoclonal gammopathy (MG) in which the clonal mass has not reached a predefined state in which the condition is considered malignant. It is a precursor to conditions such as multiple myeloma or lymphoma at a rate of ~1%/year. Thus, from a hematologic standpoint, MGUS is a fairly benign condition. However, it is now recognized that organ damage resulting from just the MG without the need MM or lymphoma can occur. One of the most recognized is nephropathy secondary to monoclonal gammopathy of renal significance (MGRS). Other well-recognized conditions include neuropathies, oculopathies and dermopathies. Some conditions such as autoimmune diseases and coagulopathies are less common and recognized. Finally, systemic involvement of multiple organs is well described in several entities. In all of these conditions, the role of the MG is no longer insignificant. Thus, the term MGUS should be avoided when describing these entities.

The impact of dialysis on the survival of patients with immunoglobulin light chain (AL) amyloidosis undergoing autologous stem cell transplantation.

BACKGROUND: Acute renal failure requiring dialysis is associated with high mortality during autologous stem cell transplantation (ASCT). This study examined the association between acute renal failure and mortality in immunoglobulin light chain (AL) amyloidosis during ASCT. METHODS: Between 1996 and 2010, 408 ASCT patients were evaluated. Data were collected from electronic medical records. RESULTS: Dialysis was performed on 72 (17.6%) patients. Eight patients started dialysis >30 days prior to ASCT (Group II), 36 started ±30 days after ASCT (Group III) and 28 initiated dialysis >1 month after ASCT (Group IV). Patients who never dialyzed were assigned to Group I. There were no significant age or sex differences. Median overall survival (OS) had not been reached in Groups I and II but was 7.0 months in Group III and 48.5 months in Group IV (P < 0.001). Treatment-related mortality (TRM) was observed in 44.4% of the patients in Group III, 6-fold higher than the next highest group (P < 0.001). The most common causes of TRM were cardiac and sepsis. In the multivariate analysis, only hypoalbuminemia (<2.5 g/dL, P < 0.001) and estimated glomerular filtration rate (eGFR) <40 mL/min/1.73 m(2) (P < 0.001) were independently associated with starting dialysis within 30 days of ASCT. CONCLUSIONS: The study found significant differences in the OS depending on when the acute renal failure occurred. Patients who required dialysis within 30 days of ASCT had the highest rate of TRM. Screening with serum albumin and eGFR may reduce the risk.

American Society of Hematology Annual Meeting 2014: highlights in multiple myeloma.

Multiple myeloma (MM) had a major presence at this meeting with 855 abstracts related to MM, 24 oral presentations and 106 posters. This, coupled with the record attendance at this year's meeting, made it a positive year for patients and clinicians alike as much of the presented data are likely to lead to major advances in the field of myeloma. Key areas of focus included: high-risk smoldering disease, minimal residual disease for monitoring response to therapy, novel therapies in clinical trials, including carfilzomib and daratumumab, and imaging modalities for MM.

The cancer glycome: carbohydrates as mediators of metastasis.

Glycosylation is a frequent post-translational modification which results in the addition of carbohydrate determinants, "glycans", to cell surface proteins and lipids. These glycan structures form the "glycome" and play an integral role in cell-cell and cell-matrix interactions through modulation of adhesion and cell trafficking. Glycosylation is increasingly recognized as a modulator of the malignant phenotype of cancer cells, where the interaction between cells and the tumor micro-environment is altered to facilitate processes such as drug resistance and metastasis. Changes in glycosylation of cell surface adhesion molecules such as selectin ligands, integrins and mucins have been implicated in the pathogenesis of several solid and hematological malignancies, often with prognostic implications. In this review we focus on the functional significance of alterations in cancer cell glycosylation, in terms of cell adhesion, trafficking and the metastatic cascade and provide insights into the prognostic and therapeutic implications of recent findings in this fast-evolving niche.

Investigating osteogenic differentiation in multiple myeloma using a novel 3D bone marrow niche model.

Clonal proliferation of plasma cells within the bone marrow (BM) affects local cells, such as mesenchymal stromal cells (MSCs), leading to osteolysis and fatality in multiple myeloma (MM). Consequently, there is an urgent need to find better mechanisms of inhibiting myeloma growth and osteolytic lesion development. To meet this need and accelerate clinical translation, better models of myeloma within the BM are required. Herein we have developed a clinically relevant, three-dimensional (3D) myeloma BM coculture model that mimics bone cell/cancer cell interactions within the bone microenvironment. The coculture model and clinical samples were used to investigate myeloma growth, osteogenesis inhibition, and myeloma-induced abnormalities in MM-MSCs. This platform demonstrated myeloma support of capillary-like assembly of endothelial cells and cell adhesion-mediated drug resistance (CAM-DR). Also, distinct normal donor (ND)- and MM-MSC miRNA (miR) signatures were identified and used to uncover osteogenic miRs of interest for osteoblast differentiation. More broadly, our 3D platform provides a simple, clinically relevant tool to model cancer growth within the bone-useful for investigating skeletal cancer biology, screening compounds, and exploring osteogenesis. Our identification and efficacy validation of novel bone anabolic miRs in MM opens more opportunities for novel approaches to cancer therapy via stromal miR modulation.

Targeting survival and cell trafficking in multiple myeloma and Waldenstrom macroglobulinemia using pan-class I PI3K inhibitor, buparlisib.

The phosphatidylinositol-3 kinase (PI3K) pathway is activated in multiple myeloma (MM) and Waldenstrom Macroglobulenima (WM), and plays a crucial role in tumor progression and drug resistance. In this study, we characterized the role of pan-class I PI3K inhibition on cell trafficking and survival of MM and WM cells. We tested the effect of pan-class I PI3K inhibition by siRNA silencing or pharmacologic inhibition with buparlisib on MM cell survival, apoptosis and cell cycle in vitro and tumor growth and mobilization of MM cells in vivo. We then evaluated buparlisib-dependent mechanisms of induced MM cell mobilization. Moreover, the effect of buparlisib on cell survival, apoptosis, and adhesion of WM cells to bone marrow stromal cells (BMSCs) has been evaluated. We showed that buparlisib induced toxicity in MM cells, supported by induction of apoptosis and cell cycle arrest. Buparlisib was also found to reduce tumor progression in vivo. Importantly, buparlisib enhanced MM cell mobilization in vivo which was driven by decreased adhesion of MM cells to BMSCs and increased chemotaxis via up-regulation of CXCR4 expression. Similar to its effects on MM cells, buparlisib also induced cell survival and apoptosis, and decreased adhesion in WM cells. These data highlight the critical contribution of class I PI3K signaling to the regulation of survival and cell dissemination in B-cell malignancies.

The sialyltransferase ST3GAL6 influences homing and survival in multiple myeloma.

Glycosylation is a stepwise procedure of covalent attachment of oligosaccharide chains to proteins or lipids, and alterations in this process, especially increased sialylation, have been associated with malignant transformation and metastasis. The role of altered sialylation in multiple myeloma (MM) cell trafficking has not been previously investigated. In the present study we identified high expression of ß-galactoside α-2,3-sialyltransferase, ST3GAL6, in MM cell lines and patients. This gene plays a key role in selectin ligand synthesis in humans through the generation of functional sialyl Lewis X. In MRC IX patients, high expression of this gene is associated with inferior overall survival. In this study we demonstrate that knockdown of ST3GAL6 results in a significant reduction in levels of α-2,3-linked sialic acid on the surface of MM cells with an associated significant reduction in adhesion to MM bone marrow stromal cells and fibronectin along with reduced transendothelial migration in vitro. In support of our in vitro findings, we demonstrate significantly reduced homing and engraftment of ST3GAL6 knockdown MM cells to the bone marrow niche in vivo, along with decreased tumor burden and prolonged survival. This study points to the importance of altered glycosylation, particularly sialylation, in MM cell adhesion and migration.

AKT as a therapeutic target in multiple myeloma.

INTRODUCTION: Multiple myeloma remains an incurable malignancy with poor survival. Novel therapeutic approaches capable of improving outcomes in patients with multiple myeloma are urgently required. AKT is a central node in the phosphatidylinositol-3-kinase/AKT/mammalian target of rapamycin signaling pathway with high expression in advanced and resistant multiple myeloma. AKT contributes to multiple oncogenic functions in multiple myeloma which may be exploited therapeutically. Promising preclinical data has lent support for pursuing further development of AKT inhibitors in multiple myeloma. Lead drugs are now entering the clinic. AREAS COVERED: The rationale for AKT inhibition in multiple myeloma, pharmacological subtypes of AKT inhibitors in development, available results of clinical studies of AKT inhibitors and suitable drug partners for further development in combination with AKT inhibition in multiple myeloma are discussed. EXPERT OPINION: AKT inhibitors are a welcome addition to the armamentarium against multiple myeloma and promising clinical activity is being reported from ongoing trials in combination with established and/or novel treatment approaches. AKT inhibitors may be set to improve patient outcomes when used in combination with synergistic drug partners.

Posterior pharyngeal candidiasis in the absence of clinically overt oral involvement: a cross-sectional study.

PURPOSE: Although oropharyngeal candidiasis is associated with inhaled corticosteroid (ICS) usage, there is sparse data on the prevalence of posterior pharyngeal candidiasis in those without any detectable oral candidiasis on clinical examination. We systematically investigated the relationship between oral candidiasis on clinical examination and the presence of posterior pharyngeal candidiasis at bronchoscopy. METHODS: We conducted a cross-sectional study on a convenience sample of 100 patients undergoing bronchoscopy at our institution. Patients were assessed for symptoms of and risk factors for candida infection and had an examination of their oropharynx for evidence of candidiasis before bronchoscopy. They subsequently had a detailed assessment for posterior candidiasis at bronchoscopy. We performed a posteriori subgroup analysis, which focused solely on those patients on ICS maintenance therapy. RESULTS: Median age was 54.7 (27-84) years, and 55 patients were male; 47 % of patients were on ICS, and 20 % of this cohort received recent oral corticosteroids. Twenty-eight percent of this convenience sample had posterior pharyngeal candidiasis; however, only 10.7 % (3/28) of these patients had clinically detectable oral candidiasis on clinical examination before bronchoscopy. Factors that were independently associated with the presence of pharyngeal candidiasis at bronchoscopy were OR (95 % CI) ICS usage 6.9 (2.5-19.2), particularly fluticasone usage 6.8 (2.62-17.9) and the presence of dysphonia 3.2 (1.3-8.0). In the subgroup analysis of ICS usage, posterior pharyngeal candidiasis was correlated with the presence of dysphonia but was not independently associated with fluticasone or budesonide dosage. CONCLUSIONS: This study demonstrates that posterior pharyngeal candidiasis in the absence of clinically overt oral candidiasis is frequent amongst ICS users. A history of ICS use, particularly fluticasone usage, as well as the presence of dysphonia are associated with posterior pharyngeal candidiasis at bronchoscopy, even in the absence of clinically overt oral involvement.

A detailed evaluation of the current renal response criteria in AL amyloidosis: is it time for a revision?

Organ response correlates with overall survival in patients with immunoglobulin light chain amyloidosis and is the goal of treatment. This study evaluates the current renal response criteria and their ability to predict overall survival. Patients with immunoglobulin light chain amyloidosis who underwent autologous stem cell transplantation between 1995 and 2010 were recruited. Eligibility criteria included >1 g/dL of proteinuria, dialysis independence at baseline and within the first year of autologous stem cell transplantation, and a minimum follow-up of 1 year. Responses were assessed by the best values after autologous stem cell transplantation. The difference between involved and uninvolved serum free light chain levels was used to determine hematologic response. Increases in serum creatinine were calculated from the highest creatinine after autologous stem cell transplantation. Inclusion and exclusion criteria were met by 141 patients. These patients had a median follow-up of 52 months. Superior overall survival was observed in patients with a >75% reduction in proteinuria and those who had a >95% reduction had additional benefits. The overall survival of patients with >50% to ≤75% proteinuria was similar to that of patients with ≤50% reduction. A rise in serum creatinine >25% was not associated with a poorer outcome in patients with a >75% reduction in proteinuria. Deeper hematologic responses were associated with higher rates of proteinuria reduction. These results suggest that further evaluation of the current renal response criteria is needed. In particular, discrimination of the renal response into complete and partial categories and modification of the serum creatinine requirement seem justified.

Acute kidney injury during leukocyte engraftment after autologous stem cell transplantation in patients with light-chain amyloidosis.

Engraftment syndrome (ES) is a complication of hematopoietic stem cell transplantation characterized by fever, rash, and non-cardiogenic pulmonary edema. Acute kidney injury (AKI) has been recognized but is considered a minor criterion in one and excluded another definition of ES. We have noted a high incidence of AKI in patients with immunoglobulin light-chain amyloidosis (AL) undergoing autologous stem cell transplant (ASCT) around the time of leukocyte engraftment. This study was conducted to further investigate the relationship between AKI and ES. Data were collected from 377 AL patients who underwent ASCT from 7/1997 to 10/2009. Patients who experienced an elevation of serum creatinine >0.5 mg/dL within 4 days of leukocyte engraftment and anyone who presented with signs associated with ES regardless of renal manifestations were included. Forty-one patients met criteria. Twelve were excluded for positive cultures (10), acute interstitial nephritis (1), and acute cellular rejection (1). In addition to AKI (93.1%), patients also exhibit fever (82.7%), hypotension (51.7%), rash (48.2%), edema (93.1%), diarrhea (69.0%), conjunctival hemorrhage (31.0%), pulmonary edema (31.0%), pulmonary hemorrhage (13.8%), and transient encephalopathy (17.2%). Patient with pulmonary involvement were more likely to require dialysis but was not statistically significant. AKI was very common during leukocyte engraftment in AL patients. While infectious etiology accounted for some of the AKI, most appeared to be associated with ES. After infection is ruled out, ES should be considered in the differential diagnosis when evaluating AKI in this population.

Uterorelaxant effect of ghrelin on human myometrial contractility.

OBJECTIVE: Ghrelin is a peptide that regulates maternal appetite and energy expenditure as well as playing a role in fetal nutrition. The purpose of the study was to investigate the effects of ghrelin on human myometrial contractility in vitro. STUDY DESIGN: Biopsy specimens of human myometrium were obtained at elective cesarean section (n = 21). Dissected myometrial strips suspended under isometric conditions, undergoing spontaneous and oxytocin-induced contractions, were exposed to cumulative additions of ghrelin in the concentration range of 1 nmol/L to 1 micromol/L. Control experiments were performed simultaneously. RESULT: Ghrelin exerted an inhibitory effect on contractility, compared with control strips. The mean maximal inhibition values were as follows: 33.66% +/- 2.63% for spontaneous contractions (n = 6; P < .05), and 31.55% +/- 4.64% for oxytocin-induced contractions (n = 6; P < .05). CONCLUSION: This inhibitory effect of ghrelin on uterine contractions suggests it plays a physiologic role in regulation of myometrial activity and further studies to evaluate the signaling pathways involved may help to define this role. These findings highlight the emerging role of metabolic modulation of myometrium, and particularly at extremes of body mass index measurements.