Pathogenesis of myeloma bone disease

Multiple myeloma: 2024 update on diagnosis, risk-stratification, and management

DISEASE OVERVIEW

Multiple myeloma accounts for approximately 10% of hematologic malignancies.

DIAGNOSIS

The diagnosis requires ≥10% clonal bone marrow plasma cells or a biopsy proven plasmacytoma plus evidence of one or more multiple myeloma defining events (MDE): CRAB (hypercalcemia, renal failure, anemia, or lytic bone lesions) attributable to the plasma cell disorder, bone marrow clonal plasmacytosis ≥60%, serum involved/uninvolved free light chain (FLC) ratio ≥100 (provided involved FLC is ≥100 mg/L and urine monoclonal protein is ≥200 mg/24 h), or >1 focal lesion on magnetic resonance imaging.

RISK STRATIFICATION

The presence of del(17p), t(4;14), t(14;16), t(14;20), gain 1q, del 1p, or p53 mutation is considered high-risk multiple myeloma. Presence of any two high risk factors is considered double-hit myeloma; three or more high risk factors is triple-hit myeloma.

RISK-ADAPTED INITIAL THERAPY

In patients who are candidates for autologous stem cell transplantation, induction therapy consists of anti-CD38 monoclonal antibody plus bortezomib, lenalidomide, dexamethasone (VRd) followed by autologous stem cell transplantation (ASCT). Selected standard risk patients can delay transplant until first relapse. Frail patients who not candidates for transplant are treated with VRd for approximately 8-12 cycles followed by maintenance or alternatively with daratumumab, lenalidomide, dexamethasone (DRd) until progression.

MAINTENANCE THERAPY

Standard risk patients need lenalidomide maintenance, while bortezomib plus lenalidomide maintenance is needed for high-risk myeloma.

MANAGEMENT OF RELAPSED DISEASE

A triplet regimen is usually needed at relapse, with the choice of regimen varying with each successive relapse. Chimeric antigen receptor T (CAR-T) cell therapy and bispecific antibodies are additional options.

Phenolic acids prevent sex-steroid deficiency-induced bone loss and bone marrow adipogenesis in mice

Phenolic acids, such as hippuric acid (HA) and 3-(3-hydroxyphenyl) propionic acid (3-3-PPA), can be produced from microbiome digestion of polyphenols. Previously it was found that HA and 3-3-PPA facilitate bone formation and suppress bone resorption. However, the mechanism of action by which HA and 3-3-PPA protect bone from degeneration is currently unknown. In this report, we present that HA and 3-3-PPA suppression of bone resorption is able to ameliorate bone loss in an ovariectomy (OVX) osteopenic mouse model though not to the extent of Zoledronic acid (ZA). HA and 3-3-PPA treatments were shown to significantly decrease bone marrow adipocyte-like cell formation and inhibited gene expression of key adipogenesis regulator peroxisome proliferator activated receptor gamma (PPARγ) and lipoprotein lipase (Lpl) in bone from OVX mice. In addition, ChIP experiments showed that the association between PPARγ and Lpl promoter region in preadipocyte-like cells was significantly suppressed following HA or 3-3-PPA treatment. Contrasting HA and 3-3-PPA, ZA significantly increased TRAP activity in the area close to growth plate and significantly suppressed bone cell proliferation. These data suggest that phenolics acids such as HA or 3-3-PPA may prevent bone degeneration after OVX through suppression of inflammatory milieu in the bone.

MicroRNA-138: an emerging regulator of skeletal development, homeostasis, and disease

Noncoding microRNAs are powerful epigenetic regulators of cellular processes by their ability to target and suppress expression of numerous protein-coding mRNAs. This multitargeting function is a unique and complex feature of microRNAs. It is now well-described that microRNAs play important roles in regulating the development and homeostasis of many cell/tissue types, including those that make up the skeletal system. In this review, we focus on microRNA-138 (miR-138) and its effects on regulating bone and cartilage cell differentiation and function. In addition to its reported role as a tumor suppressor, miR-138 appears to function as an inhibitor of osteoblast differentiation. This review provides additional information on studies that have attempted to alter miR-138 expression in vivo as a means to dampen ectopic calcification or alter bone mass. However, a review of the published literature on miR-138 in cartilage reveals a number of contradictory and inconclusive findings with respect to regulating chondrogenesis and chondrocyte catabolism. This highlights the need for more research in understanding the role of miR-138 in cartilage biology and disease. Interestingly, a number of studies in other systems have reported miR-138-mediated effects in dampening inflammation and pain responses. Future studies will reveal if a multifunctional role of miR-138 involving suppression of ectopic bone, inflammation, and pain will be beneficial in skeletal conditions such as osteoarthritis and heterotopic ossification.

Physical Activity and Patient-Reported Outcomes in Monoclonal Plasma Cell Disorders

INTRODUCTION

Plasma cell disorders (PCD) are a group of conditions characterized by disproportionate proliferation of a single clone of B lymphocytes. Multiple myeloma (MM) is a malignant type of plasma cell disorders. Improvements in MM survival have led patients and physicians to pursue strategies to improve quality of life for those living longer with this disease. Bone disease and instability associated with MM have made physicians reluctant to recommend physical activity (PA) to this patient population. The goal of this study was to examine the relationship between PA and physical and psychosocial patient-reported outcomes in patients with MM and precursor conditions.

METHODS

We used a cross-sectional study design. Questionnaires on PA, demographics, fatigue, distress, and other aspects of quality of life were posted on the HealthTree® Cure Hub website, a patient portal through which individuals with MM and related disorders obtain support, track laboratories and other information about their diseases, and participate in research.

RESULTS

A total of 794 individuals, including 664 with MM, are included in the current analysis. We observed potential inverse associations between PA and poor quality of life, including problems with sleep, fatigue, neuropathy, distress, and several psychosocial states. On average, patients reported that their PA levels have declined since diagnosis and that they would like to be even more active in the future than they were before their diagnosis.

CONCLUSIONS

In our cross-sectional study, regular PA was associated with multiple quality-of-life indicators and other patient-reported outcomes, including better sleep and less fatigue, neuropathy, and distress. The findings of this study can help guide the design of prospective studies of the role of PA in MM survivorship.

Multiple myeloma presenting as blepharitis in a horse

Myeloma-related disorders, including multiple myeloma, extramedullary plasmacytoma, and solid osseous plasmacytoma, are rare in horses. Clinical complaints for myeloma-related disorders are nonspecific, and when present, M-protein location is more variable on protein electrophoresis in horses relative to dogs and cats. Here, we describe a case of a 15-year-old Thoroughbred mare who presented with recurrent blepharitis. Marked hyperglobulinemia was an incidental finding on routine hematologic and biochemical testing. Bone marrow aspiration consisted of >30% plasma cells, and serum protein electrophoresis demonstrated a monoclonal gammopathy in the alpha 2 fraction leading to a diagnosis of multiple myeloma. Immunofixation and radial immunodiffusion confirmed the presence of an IgG M-protein. Based on a restricted peak in the alpha 2 location, the specific M-protein is suspected to be IgG(T), an IgG isotype unique to horses. M-protein migration in horses is variable relative to dogs and cats, yet immunofixation can still be used to identify equine IgG M-protein isotypes. The unique clinical presentation in this case also serves as a reminder to consider neoplasia in horses with unusual or nonspecific clinical signs.

Diagnostic value of machine learning-based computed tomography texture analysis for differentiating multiple myeloma from osteolytic metastatic bone lesions in the peripheral skeleton

OBJECTIVES

To report the diagnostic performance of machine learning-based CT texture analysis for differentiating multiple myeloma from osteolytic metastatic bone lesions in the peripheral skeleton.

METHODS

We retrospectively evaluated 172 patients with multiple myeloma (n = 70) and osteolytic metastatic bone lesions (n = 102) in the peripheral skeleton. Two radiologists individually used two-dimensional manual segmentation to extract texture features from non-contrast CT. In total, 762 radiomic features were extracted. Dimension reduction was performed in three stages: inter-observer agreement analysis, collinearity analysis, and feature selection. Data were randomly divided into training (n = 120) and test (n = 52) groups. Eight machine learning algorithms were used for model development. The primary performance metrics were the area under the receiver operating characteristic curve and accuracy.

RESULTS

In total, 476 of the 762 texture features demonstrated excellent interobserver agreement. The number of features was reduced to 22 after excluding those with strong collinearity. Of these features, six were included in the machine learning algorithms using the wrapper-based classifier-specific technique. When all eight machine learning algorithms were considered for differentiating multiple myeloma from osteolytic metastatic bone lesions in the peripheral skeleton, the area under the receiver operating characteristic curve and accuracy were 0.776-0.932 and 78.8-92.3%, respectively. The k-nearest neighbors model performed the best, with the area under the receiver operating characteristic curve and accuracy values of 0.902 and 92.3%, respectively.

CONCLUSION

Machine learning-based CT texture analysis is a promising method for discriminating multiple myeloma from osteolytic metastatic bone lesions.

Breaking through Multiple Myeloma: A Paradigm for a Comprehensive Tumor Ecosystem Targeting

Multiple myeloma (MM) is a cancerous condition characterized by the proliferation of plasma cells within the hematopoietic marrow, resulting in multiple osteolytic lesions. MM patients typically experience bone pain, kidney damage, fatigue due to anemia, and infections. Historically, MM was an incurable disease with a life expectancy of around three years after diagnosis. However, over the past two decades, the development of novel therapeutics has significantly improved patient outcomes, including response to treatment, remission duration, quality of life, and overall survival. These advancements include thalidomide and its derivatives, lenalidomide and pomalidomide, which exhibit diverse mechanisms of action against the plasma cell clone. Additionally, proteasome inhibitors such as bortezomib, ixazomib, and carfilzomib disrupt protein degradation, proving specifically toxic to cancerous plasma cells. Recent advancements also involve monoclonal antibodies targeting surface antigens, such as elotuzumab (anti-CS1) and daratumumab (anti-CD38), bispecific t-cell engagers such as teclistamab (anti-BCMA/CD3) and Chimeric antigen receptor T (CAR-T)-based strategies, with a growing focus on drugs that exhibit increasingly targeted action against neoplastic plasma cells and relevant effects on the tumor microenvironment.

The Global Prevalence of Vitamin D Deficiency and Insufficiency in Patients with Multiple Myeloma: A Systematic Review and Meta-Analysis

BACKGROUND

Multiple myeloma (MM) is a hematological malignancy characterized by the exponential growth of malignant plasma cells. Individuals diagnosed with MM exhibit a deficiency in vitamin D and may suffer fatigue, a loss of muscular strength, persistent musculoskeletal aches, and pain. The objective of this systematic review and meta-analysis is to determine the prevalence of vitamin D insufficiency and deficiency in individuals diagnosed with MM.

METHODS

We searched five electronic databases using relevant keywords. The quality of the included studies was evaluated using the critical appraisal tool developed by the Joanna Briggs Institute. We employed a random-effects model and presented the findings in the form of percentages accompanied by 95% confidence intervals (CI). This protocol has been officially registered in PROSPERO under the registration number CRD42021248710.

RESULTS

The meta-analysis comprised a total of eighteen studies and found that, among patients with MM, the occurrence of serum vitamin D deficiency and insufficiency was 39.4% (95% CI: 25.8 to 52.9, n = 3746) and 34.1% (95% CI: 20.9 to 47.2, n = 3559), respectively. The findings indicate that a greater proportion of newly diagnosed patients exhibited vitamin D deficiency and insufficiency, with rates of 43.0% and 41.6%, respectively, compared to those receiving treatment (rates of 41.6% and 32.3%, respectively). The findings of the sensitivity analyses were consistent, and most of the studies (72.2%) were deemed to be of high quality. The results of Egger's test indicated the absence of publication bias.

CONCLUSIONS

Patients diagnosed with MM have been found to exhibit significantly elevated levels of both vitamin D deficiency and insufficiency. Therefore, it is recommended to consider vitamin D testing as an additional parameter in the current criteria for the clinical evaluation of MM.

Exercise Preferences, Barriers, and Facilitators of Individuals With Cancer Undergoing Chemotherapy Before Stem Cell Transplantation: A Mixed-Methods Study

BACKGROUND

Exercise can help mitigate side effects of hematopoietic stem cell transplantation (HSCT), particularly when initiated before HSCT. However, the exercise-related barriers, facilitators, and preferences of this population remain unclear.

OBJECTIVE

This study aimed to explore the patient experience to inform future implementation of a prehabilitation intervention.

INTERVENTIONS/METHODS

A 2-phase sequential explanatory mixed-methods study was conducted using (1) cross-sectional survey and (2) focus groups. Survey questions aligned with the Theoretical Domains Framework. Focus group data were analyzed using a directed content analysis approach, followed by inductive thematic analysis to generate themes that represented the exercise-related barriers, facilitators, and preferences of participants.

RESULTS

Twenty-six participants completed phase 1 (n = 22 with multiple myeloma). Fifty percent of participants (n = 13) were fairly/very confident in their ability to exercise pre-HSCT. Eleven participants completed phase 2. Exercise barriers included knowledge/skill limitations, inadequate healthcare provider support, and the emotional toll of treatment. Facilitators included social support and goals. Exercise preferences were related to 2 themes: (1) program structure (subthemes: prescription and scheduling, mode of delivery) and (2) support (subthemes: support from personnel, tailoring, and education).

CONCLUSION

Key exercise-related barriers included knowledge limitations, disease/treatment effects, and inadequate support. Prehabilitation should be tailored, flexible, and include education and a virtual or hybrid delivery model in this population.

IMPLICATIONS FOR PRACTICE

Nurses are well positioned to identify functional limitations and counsel and refer patients to exercise programming and/or physiotherapy services. Including an exercise professional in the pretransplant care team would provide key supportive care assistance for the nursing team.

The Metabolic Features of Osteoblasts: Implications for Multiple Myeloma (MM) Bone Disease

The study of osteoblast (OB) metabolism has recently received increased attention due to the considerable amount of energy used during the bone remodeling process. In addition to glucose, the main nutrient for the osteoblast lineages, recent data highlight the importance of amino acid and fatty acid metabolism in providing the fuel necessary for the proper functioning of OBs. Among the amino acids, it has been reported that OBs are largely dependent on glutamine (Gln) for their differentiation and activity. In this review, we describe the main metabolic pathways governing OBs' fate and functions, both in physiological and pathological malignant conditions. In particular, we focus on multiple myeloma (MM) bone disease, which is characterized by a severe imbalance in OB differentiation due to the presence of malignant plasma cells into the bone microenvironment. Here, we describe the most important metabolic alterations involved in the inhibition of OB formation and activity in MM patients.

Metabolic features of myeloma cells in the context of bone microenvironment: Implication for the pathophysiology and clinic of myeloma bone disease

Multiple myeloma (MM) is a hematological malignancy characterized by the accumulation of malignant plasma cells (PCs) into the bone marrow (BM). The complex interaction between the BM microenvironment and MM PCs can lead to severe impairment of bone remodeling. Indeed, the BM microenvironment exerts a critical role in the survival of malignant PCs. Growing evidence indicates that MM cells have several metabolic features including enhanced glycolysis and an increase in lactate production through the upregulation of glucose transporters and enzymes. More recently, it has been reported that MM cells arehighly glutamine addicted. Interestingly, these metabolic changes in MM cells may affect BM microenvironment cells by altering the differentiation process of osteoblasts from mesenchymal stromal cells. The identification of glutamine metabolism alterations in MM cells and bone microenvironment may provide a rationale to design new therapeutic approaches and diagnostic tools. The osteolytic lesions are the most frequent clinical features in MM patients, often characterized by pathological fractures and acute pain. The use of the newer imaging techniques such as Magnetic Resonance Imaging (MRI) and combined Positron Emission Tomography (PET) and Computerized Tomography (CT) has been introduced into clinical practice to better define the skeletal involvement. Currently, the PET/CT with ¹⁸F-fluorodeoxyglucose (FDG) is the diagnostic gold standard to detect active MM bone disease due to the high glycolytic activity of MM cells. However, new tracers are actively under investigation because a portion of MM patients remains negative at the skeletal level by ¹⁸F-FDG. In this review, we will summarize the existing knowledge on the metabolic alterations of MM cells considering their impact on the BM microenvironment cells and particularly in the subsequent formation of osteolytic bone lesions. Based on this, we will discuss the identification of possible new druggable targets and the use of novel metabolic targets for PET imaging in the detection of skeletal lesions, in the staging and treatment response of MM patients.

Feasibility of a tailored and virtually supported home exercise program for people with multiple myeloma using a novel eHealth application

Introduction

eHealth exercise interventions have the unique ability to leverage the benefits of in-person programming (tailoring and supervision) with the benefits of home programming (flexibility). There may be a role for eHealth-delivered exercise for people with multiple myeloma (MM), as exercise tailoring and supervision are critical for successful outcomes due to the significant impacts/risks of myeloma-related side effects. The purpose of this study was to determine the safety, feasibility, and preliminary efficacy of a 12-week virtually supported eHealth exercise program.

Methods

Participants with MM completed a 12-week virtually supported home exercise program involving virtually supervised group workouts, independent workouts, and aerobic exercise. Tailoring was facilitated by the functionality of HEAL-Me, a novel eHealth app. Participants completed virtual fitness assessments and questionnaires at baseline and week 12.

Results

Twenty-nine participants consented, 26 completed all follow-up testing (90%). Exercise adherence was 90% (group), 83% (independent), and 90% (aerobic). No serious adverse events (grade ≥3) occurred. Significant improvements were found for quality of life and physical fitness. There was a high level of program/app satisfaction: 96% of participants agreed or strongly agreed that the exercise program was beneficial, 93% found it enjoyable, 89% were satisfied or very satisfied with delivery through the HEAL-Me app, and 48% felt that the eHealth program helped them manage cancer-related symptoms and side-effects.

Conclusion

An eHealth intervention that is individually tailored and includes virtual supervision and active support from the healthcare team is feasible and acceptable to people with MM. The findings from this study warrant investigation using a large-scale randomized controlled trial.

Evaluation of mandibular bone changes in multiple myeloma patients on dental panoramic radiographs

OBJECTIVE

The aim of this study is to assess the mandibular bone structures of multiple myeloma (MM) patients on panoramic radiographs using fractal analysis (FA) and radio-morphometric indices.

METHODS

The study group consisted of 67 MM patients, and the control group consisted of 67 individuals without any systemic disease. The mandibular cortical index (MCI) classification, antegonial index (AGI), gonial index (GI), mandibular cortical width (MCW), panoramic mandibular index (PMI) and fractal dimensions (FD) were evaluated on panoramic radiographs. FD measurements were made by identifying 4 related areas. Shapiro-Wilk test was used to determine the normal distribution of the data. Chi-square and independent t tests were used to compare the findings between the two groups.

RESULTS

The FD values of the study group in ROI1, ROI2, ROI3, ROI4 regions and GI values were found to be statistically significantly lower than the control group (p < 0.001). There was no statistically significant difference between the two groups in terms of AGI, MCW and PMI values (p > 0.05). While C1 was the most common type in the control group, C2 was the most common type in the study group. C2 and C3 were detected more in the study group than in the control group (p < 0.001).

CONCLUSION

Our study showed a consensus with the studies advocating that fractal analysis and radio-morphometric indices are methods that can be used to determine mandibular bone density. The low bone density of MM patients is a condition that physicians should be aware of for interventional dental procedures.

CST6 suppresses osteolytic bone disease in multiple myeloma by blocking osteoclast differentiation

Osteolytic bone disease is a hallmark of multiple myeloma (MM). A significant fraction (~20%) of MM patients do not develop osteolytic lesions (OL). The molecular basis for the absence of bone disease in MM is not understood. We combined PET-CT and gene expression profiling (GEP) of purified bone marrow (BM) CD138+ MM cells from 512 newly diagnosed MM patients to reveal that elevated expression of cystatin M/E (CST6) was significantly associated with the absence of OL in MM. An enzyme-linked immunosorbent assay revealed a strong correlation between CST6 levels in BM serum/plasma and CST6 mRNA expression. Both recombinant CST6 protein and BM serum from patients with high CST6 significantly inhibited the activity of the osteoclast-specific protease cathepsin K, and blocked osteoclast differentiation and function. Recombinant CST6 inhibited bone destruction in ex vivo and in vivo myeloma models. Single cell RNA-sequencing identified that CST6 attenuates polarization of monocytes to osteoclast precursors. Furthermore, CST6 protein blocks osteoclast differentiation by suppressing cathepsin-mediated cleavage of NF-κB/p100 and TRAF3 following RANKL stimulation. Secretion by MM cells of CST6, an inhibitor of osteoclast differentiation and function, suppresses osteolytic bone disease in MM and probably other diseases associated with osteoclast-mediated bone loss.

Bone metabolism parameters and their relation to cytogenetics in multiple myeloma

OBJECTIVES

Our aim was to correlate serum levels of selected markers of bone metabolism and bone marrow microenvironment to cytogenetic changes in patients with multiple myeloma (MM).

METHODS

We assed cytogenetic changes in 308 patients and correlated them with the following levels of bone marrow metabolism: thymidine kinase (TK), β2-microglobulin (b-2-m), Dickkopf-1 protein (DKK-1), C-terminal telopeptide collagen-I (ICTP), N-terminal propeptide of type I procollagen (PINP), receptor for interleukin 6 (rIL-6), vascular cell adhesive molecule-1 (VCAM), soluble intercellular adhesion molecule-1, osteoprotegerin (OPG), hepatocyte growth factor (HGF), vascular endothelial growth factor (VEGF), syndecan-1 (SYN-1) and Fas antigen.

RESULT

Individuals with delRB1 had lower levels of OPG (M = 7.39 vs. 5.46 pmol/L, p = .025) and VEGF (M = 304 vs. 196 pg/ml; p = .036). t(14;16) was associated with higher β2m levels (M = 7.59 vs. 4.13 mg/L; p = .022) and lower DKK-1 levels (M = 4465 ng/L vs. 12,593). The presence of 1q21 gain was associated with higher levels of TK (M = 100.0 vs. 11.0 IU/L, p = .026) and lower levels of PINP (M = 49.3 vs. 67.4 mg/L, p = .030).

CONCLUSIONS

Our analysis has shown, some cytogenetic changes, especially delRB1, t(14;16) and 1q21gain, which affect the components of the cytokine network in multiple myeloma.

Hypercalcaemia and acute kidney injury: A rare presentation of seminoma

Introduction:

Hypercalcaemia is common in patients with malignancy, but is rare in seminoma with only eight cases reported in the literature.

Case presentation:

We present an unusual case of a 36-year-old man who presented with hypercalcaemia and stage 3 acute kidney injury. He presented initially with headache and malaise, and was found to have markedly deranged blood tests. He underwent a renal biopsy before imaging confirmed an unexpected large abdominal mass, which was confirmed histologically to be a seminoma.

Conclusion:

He was referred to a tertiary oncology centre, and underwent emergency chemotherapy and radical resection with no evidence of recurrence to this date and with return to normocalcaemia.

The Osteoclast Traces the Route to Bone Tumors and Metastases

Osteoclasts are highly specialized cells of the bone, with a unique apparatus responsible for resorption in the process of bone remodeling. They are derived from differentiation and fusion of hematopoietic precursors, committed to form mature osteoclasts in response to finely regulated stimuli produced by bone marrow–derived cells belonging to the stromal lineage. Despite a highly specific function confined to bone degradation, emerging evidence supports their relevant implication in bone tumors and metastases. In this review, we summarize the physiological role of osteoclasts and then focus our attention on their involvement in skeletal tumors, both primary and metastatic. We highlight how osteoclast-mediated bone erosion confers increased aggressiveness to primary tumors, even those with benign features. We also outline how breast and pancreas cancer cells promote osteoclastogenesis to fuel their metastatic process to the bone. Furthermore, we emphasize the role of osteoclasts in reactivating dormant cancer cells within the bone marrow niches for manifestation of overt metastases, even decades after homing of latent disseminated cells. Finally, we point out the importance of counteracting tumor progression and dissemination through pharmacological treatments based on a better understanding of molecular mechanisms underlying osteoclast lytic activity and their recruitment from cancer cells.

Multiple myeloma: 2022 update on diagnosis, risk stratification, and management

DISEASE OVERVIEW

Multiple myeloma accounts for approximately 10% of hematologic malignancies.

DIAGNOSIS

The diagnosis requires ≥10% clonal bone marrow plasma cells or a biopsy-proven plasmacytoma plus evidence of one or more multiple myeloma defining events (MDE): CRAB (hypercalcemia, renal failure, anemia, or lytic bone lesions) attributable to the plasma cell disorder, bone marrow clonal plasmacytosis ≥60%, serum involved/uninvolved free light chain (FLC) ratio ≥ 100 (provided involved FLC is ≥100 mg/L), or >1 focal lesion on magnetic resonance imaging.

RISK STRATIFICATION

The presence of del(17p), t(4;14), t(14;16), t(14;20), gain 1q, or p53 mutation is considered high-risk multiple myeloma. The presence of any two high risk factors is considered double-hit myeloma, and three or more high risk factors is triple-hit myeloma.

RISK-ADAPTED INITIAL THERAPY

In patients who are candidates for autologous stem cell transplantation, induction therapy consists of bortezomib, lenalidomide, dexamethasone (VRd) given for approximately 3-4 cycles followed by autologous stem cell transplantation (ASCT). In high-risk patients, daratumumab, bortezomib, lenalidomide, dexamethasone (Dara-VRd) is an alternative to VRd. Selected standard-risk patients can collect stem cells, get additional cycles of induction therapy, and delay transplant until first relapse. Patients who are not candidates for transplant are treated with VRd for approximately 8-12 cycles followed by maintenance or alternatively with daratumumab, lenalidomide, dexamethasone (DRd) until progression.

MAINTENANCE THERAPY

Standard-risk patients need lenalidomide maintenance, while bortezomib plus lenalidomide maintenance is needed for high-risk myeloma.

MANAGEMENT OF RELAPSED DISEASE

A triplet regimen is usually needed at relapse, with the choice of regimen varying with each successive relapse.

Intramedullary nailing for pathological fractures of the proximal humerus caused by multiple myeloma: A case report and review of literature

BACKGROUND

Multiple myeloma (MM) bone disease is indicative of MM, and reduces patient life quality. In addition to oncological, antineoplastic systemic therapy, surgical therapy in patients with MM is an essential treatment within the framework of supportive therapy measures and involves orthopedic tumor surgery. Nevertheless, there are few reports on intramedullary (IM) nailing in the treatment of MM-induced proximal humeral fracture to prevent fixation loss. We here describe a case of pathological fracture of the proximal humerus caused by MM successfully treated with IM nailing without removal of tumors and a review of the current literature.

CASE SUMMARY

A 64-year-old male patient complaining of serious left shoulder pain and limited movement was admitted. The patient was finally diagnosed with MM (IgAλ, IIIA/II). After treatment of the pathological fracture with IM nailing, the patient's function recovered and his pain was rapidly relieved. Histopathological examination demonstrated plasma cell myeloma. The patient received chemotherapy in the Hematology Department. The humeral fracture displayed good union during the 40-mo follow-up, with complete healing of the fracture, and the clinical outcome was satisfactory. At the most recent follow-up, the patient's function was assessed using the Musculoskeletal Tumor Society score, which was 29.

CONCLUSION

Early surgery should be performed for the fracture of the proximal humerus caused by MM. IM nailing can be used without removal of tumors. Bone cement augmentation for bone defects and local adjuvant therapy can also be employed.

Pathogenesis and Treatment of Myeloma-Related Bone Disease

Multiple myeloma is a hematologic malignancy of plasma cells that causes bone-destructive lesions and associated skeletal-related events (SREs). The pathogenesis of myeloma-related bone disease (MBD) is the imbalance of the bone-remodeling process, which results from osteoclast activation, osteoblast suppression, and the immunosuppressed bone marrow microenvironment. Many important signaling cascades, including the RANKL/RANK/OPG axis, Notch signaling, the Wnt/β-Catenin signaling pathways, and signaling molecules, such as DKK-1, sclerostin, osteopontin, activin A, chemokines, and interleukins are involved and play critical roles in MBD. Currently, bisphosphonate and denosumab are the gold standard for MBD prevention and treatment. As the molecular mechanisms of MBD become increasingly well understood, novel agents are being thoroughly explored in both preclinical and clinical settings. Herein, we will provide an updated overview of the pathogenesis of MBD, summarize the clinical management and guidelines, and discuss novel bone-modifying therapies for further management of MBD.

An Individualized Exercise Intervention for People with Multiple Myeloma—Study Protocol of a Randomized Waitlist-Controlled Trial

People with multiple myeloma (MM) are second only to people with lung cancer for the poorest reported health-related quality of life (HRQoL) of all cancer types. Whether exercise can improve HRQoL in MM, where bone pain and lesions are common, requires investigation. This trial aims to evaluate the efficacy of an exercise intervention compared with control on HRQoL in people with MM. Following baseline testing, people with MM (n = 60) will be randomized to an exercise (EX) or waitlist control (WT) group. EX will complete 12-weeks of supervised (24 sessions) and unsupervised (12 sessions) individualized, modular multimodal exercise training. From weeks 12–52, EX continue unsupervised training thrice weekly, with one optional supervised group-based session weekly from weeks 12–24. The WT will be asked to maintain their current activity levels for the first 12-weeks, before completing the same protocol as EX for the following 52 weeks. Primary (patient-reported HRQoL) and secondary (bone health and pain, fatigue, cardiorespiratory fitness, muscle strength, body composition, disease response, and blood biomarkers) outcomes will be assessed at baseline, 12-, 24- and 52-weeks. Adverse events, attendance, and adherence will be recorded and cost-effectiveness analysis performed. The findings will inform whether exercise should be included as part of standard myeloma care to improve the health of this unique population.

The Role of Sclerostin in Bone Diseases

Sclerostin has been identified as an important regulator of bone homeostasis through inhibition of the canonical Wnt-signaling pathway, and it is involved in the pathogenesis of many different skeletal diseases. Many studies have been published in the last few years regarding sclerostin’s origin, regulation, and mechanism of action. The ongoing research emphasizes the potential therapeutic implications of sclerostin in many pathological conditions with or without skeletal involvement. Antisclerostin antibodies have recently been approved for the treatment of osteoporosis, and several animal studies and clinical trials are currently under way to evaluate the effectiveness of antisclerostin antibodies in the treatment of other than osteoporosis skeletal disorders and cancer with promising results. Understanding the exact role of sclerostin may lead to new therapeutic approaches for the treatment of skeletal disorders.

Molecular Systems Architecture of Interactome in the Acute Myeloid Leukemia Microenvironment

A molecular systems architecture is presented for acute myeloid leukemia (AML) to provide a framework for organizing the complexity of biomolecular interactions. AML is a multifactorial disease resulting from impaired differentiation and increased proliferation of hematopoietic precursor cells involving genetic mutations, signaling pathways related to the cancer cell genetics, and molecular interactions between the cancer cell and the tumor microenvironment, including endothelial cells, fibroblasts, myeloid-derived suppressor cells, bone marrow stromal cells, and immune cells (e.g., T-regs, T-helper 1 cells, T-helper 17 cells, T-effector cells, natural killer cells, and dendritic cells). This molecular systems architecture provides a layered understanding of intra- and inter-cellular interactions in the AML cancer cell and the cells in the stromal microenvironment. The molecular systems architecture may be utilized for target identification and the discovery of single and combination therapeutics and strategies to treat AML.

Comparison of [68Ga]-FAPI PET/CT and [18F]-FDG PET/CT in Multiple Myeloma: Clinical Experience

Objective: In this study, we aimed to compare [68Ga]FAPI PET/CT and [18F]FDG PET/CT imaging to detect lesions in multiple myeloma. Methods: A total of 14 patients with multiple myeloma who underwent [68Ga]FAPI PET/CT and [18F]FDG PET/CT imaging were included in this retrospective study. SUVmax values of [68Ga]FAPI and [18F]FDG were compared according to lesion locations. Also, lesion localization ability of both imaging methods was compared on the patient basis. Results: In 4 of 14 patients, [68Ga]FAPI PET/CT and [18F]FDG PET/CT have not detected any bone lesions. In 8 of the remaining 10 patients [18F]FDG PET/CT detected bone lesions but in this group, 6 patients showed more higher SUVmax values than [18F]FDG PET/CT in [68Ga]FAPI PET/CT.In contrast, 2 of 8 patients showed more higher SUVmax values than [68Ga]FAPI PET/CT in [18F]FDG PET/CT. Moreover, [68Ga]FAPI PET/CT detected bone lesions in two patients, which werenot detected by [18F]FDG PET/CT. Also, in five patients, [68Ga]FAPI PET/CT showed more bone lesions in comparison with[18F]FDG PET/CT. Only one patient, [18F]FDG PET/CT showed more bone lesions. Three extramedullary involvements were observed in the following locations: lung, presacral lymph node, and soft tissue mass lateral to the right maxillary sinus. Among these involvements, higher SUVmax values were observed in the lung and presacral lymph node with [68Ga]FAPI compared to [18F]FDG. However, the soft tissue mass showed a higher SUVmax value in [18F]FDG than [68Ga]FAPI. Conclusions: No significant superiority was observed in [68Ga]FAPI PET/CT over [18F]FDG PET/CT in patients with MM. However, [68Ga]FAPI PET/CT can be utilized as a complementary imaging method to [18F]FDG PET/CT in some settings, especially in low-[18F]FDG affinity and inconclusive cases. Considering the favorable aspects of [68Ga]FAPI PET/CT in MM, such as low background activity, absence of non-specific bone marrow, and physiological brain involvement, further studies with a larger sample size should be conducted.

Bacterial infections exacerbate myeloma bone disease

Multiple myeloma is characterized by osteolytic lesions caused by reduced bone formation and activated bone resorption. An important feature of myeloma is a failure of bone healing after successful treatment. In this work, clinical studies indicated a highly positive correlation between bone marrow bacteria abundance and bone lesion numbers of myeloma patients in complete remission. Coculture experiments demonstrated that marrow Escherichia coli (E. coli) promotes osteoclast differentiation and inhibits osteoblast differentiation. Mechanism studies showed that E. coli lipopolysaccharides (LPS) activated NF-κB p65 signaling and reduced phosphorylated smad1/5/9 binding ability with RUNX2 promoter, leading to decreased RUNX2 expression in osteoblast progenitors. Additionally, LPS enhanced phosphorylated NF-κB p65 binding ability with NFATc1 promoter, leading to increased NFATc1 expression in osteoclast progenitors. In vivo studies revealed E. coli contributes to osteolytic bone lesion, and elimination of E. coli infection assists healing of bone lesion in mouse model of myeloma in complete remission. These findings establish a heretofore unrecognized effect for E. coli in the genesis of myeloma bone disease and suggest a new treatment strategy.

Unstable Pathologic Vertebral Fractures in Multiple Myeloma : Propensity Score Matched Cohort Study between Reconstructive Surgery with Adjuvant Radiotherapy and Radiotherapy Alone

Objective

Although radiotherapy (RT) is recommended for multiple myeloma (MM) involving spine, the treatment of choice between reconstructive surgery with RT and RT alone for pathologic vertebral fractures (PVFs) associated with structural instability or neurologic compromises remains controversial. The purpose of this study was to evaluate the clinical efficacies of reconstructive surgery with adjuvant RT for treatment of MM with PVFs by comparing with matched cohorts treated with RT alone.

Methods

Twenty-eight patients underwent reconstructive surgery followed by RT between 2008 and 2015 in a single institution, for management of PVFs associated with structural instability of the spine and/or neurologic compromises (group I). Twenty-eight patients were treated with RT alone (group II) after propensity score matching in a 1-to-1 format based on instability of the spine, as well as age and performance. Clinical outcomes including the overall survival rates, duration of independent ambulation, neurological status, and numeric rating scale (NRS) for back pain were compared.

Results

Clinical and radiological features before treatment were similar in both groups. The median survival period was similar between the two groups. However, the mean duration of independent ambulation was significantly longer in group I (88.8 months; 95% confidence interval [CI], 66.0–111.5) than in group II (39.4 months; 95% CI, 25.2–53.6) (log rank test; p=0.022). Deterioration of Frankel grade (21.4% vs. 60.7%, p=0.024) and NRS for back pain (2.7±2.2 vs. 5.0±2.7, p=0.000) at the last follow-up were higher in the group II. Treatment-related complications were similar in both groups.

Conclusion

In patients with unstable PVFs due to MM, reconstructive surgery may yield superior clinical outcomes compared with RT alone in maintaining independent ambulation and neurological status, as well as pain control despite similar median survival and complications.

Runx2 deficiency in osteoblasts promotes myeloma resistance to bortezomib by increasing TSP-1-dependent TGF-β1 activation and suppressing immunity in bone marrow

Multiple myeloma (MM) is a plasma cell malignancy that thrives in the bone marrow (BM). The proteasome inhibitor bortezomib (BTZ) is one of the most effective front-line chemotherapeutic drugs for MM; however, 15-20% of high-risk patients do not respond to or become resistant to this drug and the mechanisms of chemoresistance remain unclear. We previously demonstrated that MM cells inhibit Runt-related transcription factor 2 (Runx2) in pre- and immature osteoblasts (OBs), and that this OB-Runx2 deficiency induces a cytokine-rich and immunosuppressive microenvironment in the BM. In the current study, we assessed the impact of OB-Runx2 deficiency on the outcome of BTZ treatment using OB-Runx2+/+ and OB-Runx2-/- mouse models of MM. In vitro and in vivo experiments revealed that OB-Runx2 deficiency induces MM cell resistance to BTZ via the upregulation of immunosuppressive myeloid-derived suppressor cells (MDSCs), downregulation of cytotoxic T cells, and activation of TGF-β1 in the BM. In MM tumor-bearing OB-Runx2-/- mice, treatment with SRI31277, an antagonist of thrombospondin-1 (TSP-1)-mediated TGF-β1 activation, reversed the BM immunosuppression and significantly reduced tumor burden. Furthermore, treatment with SRI31277 combined with BTZ alleviated MM cell resistance to BTZ-induced apoptosis caused by OB-Runx2 deficiency in co-cultured cells and produced a synergistic effect on tumor burden in OB-Runx2-/- mice. Depletion of MDSCs by 5-fluorouracil or gemcitabine similarly reversed the immunosuppressive effects and BTZ resistance induced by OB-Runx2 deficiency in tumor-bearing mice, indicating the importance of the immune environment for drug resistance and suggesting new strategies to overcome BTZ resistance in the treatment of MM.

Are the Derived Indexes of Peripheral Whole Blood Cell Counts (NLR, PLR, LMR/MLR) Clinically Significant Prognostic Biomarkers in Multiple Myeloma? A Systematic Review And Meta-Analysis

Background

Multiple myeloma (MM) is an incurable malignant plasma cell tumor. Whole blood cell count (WBCC) derived indexes are widely used as a predictive biomarker for various types of solid and hematological malignant tumors. Our study is to evaluate its effectiveness in MM by meta-analysis.

Methods

Relevant literatures were retrieved from PubMed, Embase and Web of Science databases according to PRISMA guideline. All relevant parameters were extracted and combined for statistical analysis.

Results

Nineteen studies incorporating 3818 MM patients were eventually included in this meta-analysis. 13 studies evaluated that elevated NLR was significantly associated with poor survival outcomes (OS: HR=2.04, P<0.001; PFS: HR=1.96, P=0.003). Elevated NLR was revealed to correlate with ISS stage (ISS III VS I-II, OR=2.23, P=0.003). A total of 7 studies have shown that elevated LMR predicts a better prognosis in MM patients (OS: HR=0.57, P<0.001; PFS: HR=0.49, P<0.05), and two other studies demonstrated that increased MLR was related to poor OS/PFS (OS: HR=1.58, P<0.05; PFS: HR=1.60, P<0.05). However, in the other 6 studies including 1560 patients, the prognostic value of PLR had not been confirmed (OS: HR=0.89, P>0.05; PFS: HR=0.87, P>0.05).

Conclusions

The indexes NLR and LMR/MLR derived from WBCC were validated to be useful biomarkers to predict the prognosis in MM patients, but the evidence of PLR was insufficient.

Computed tomography characteristics of multiple myeloma and other osteolytic metastatic bone lesions

BACKGROUND

Differentiation of multiple myeloma (MM) from osteolytic metastatic (OM) bone lesions may be critical in patients with lytic bone lesions but can be challenging for radiologists.

PURPOSE

To determine whether computed tomography (CT) can be used to distinguish between MM and other OM bone lesions.

MATERIAL AND METHODS

In this retrospective study, 320 lesions of 207 patients diagnosed with MM or OM, based on biopsy or clinical examination, were evaluated. Eight qualitative features were evaluated by two radiologists blinded to the diagnoses. The chi-square and Fisher exact tests, and logistic regression analysis, were used to evaluate the relationships between the CT findings and diagnoses.

RESULTS

High-density areas were more common in OM than MM lesions (85.2% and 19%, P < 0.001), as were perilesional sclerosis (38.9% vs. 13.2%, P < 0.001), heterogeneity (on non-contrast CT images, 60% vs. 19.1%, P < 0.001; on contrast enhanced CT images, 80.6% vs. 28.2%, P < 0.001), and ill-defined margins (34.6% vs. 9.1%, P < 0.001). Similarly, OM lesions showed high-density areas more than MM in evaluation of skeletal system subgroups (vertebrae, 93.8% vs. 29.8%, P < 0.0001; thoracic cage bones, 69.6% vs. 19.2%, P < 0.001; pelvic bones and sacrum, 84.8% vs. 7.7%, P < 0.001; peripheral skeletal bones, 81.5% vs. 8.3%, P < 0.001). Logistic regression analysis revealed that the presence of a high-density area in the lesion increased the probability of a metastasis 25.88-fold (R² = 0.516, P < 0.001).

CONCLUSION

MM and OM lesions can be differentiated by CT; OM lesions exhibit high- density areas.

Aberrant ENPP2 expression promotes tumor progression in multiple myeloma

Ectonucleotide pyrophosphatase/phosphodiesterase 2 (ENPP2) has been recently linked to tumor development. However, its role in modulating multiple myeloma (MM) disease progression remains unclear. Here, we demonstrated that CD138+ cells isolated from MM patients presented with higher expression of ENPP2 compared with CD138- cells. Treatment of MM cells with IL-6 resulted in ENPP2 upregulation. ENPP2 overexpression promoted proliferation, inhibited apoptosis, increased lysophosphatidic acid (LPA) generation, and upregulated osteoclastogenesis mediator expression in MM cells. In contrast, ENPP2 inhibition induced apoptosis, suppressed proliferation and survival, decreased LPA generation and downregulated osteoclastogenesis mediator expression. In an MM xenograft mouse model, ENPP2 knockdown significantly reduced MM tumor burden by inhibiting cell proliferation and inducing apoptosis. Furthermore, ENPP2 knockdown decreased the levels of LPA, osteoclastogenesis mediators in sera of mice with MM. Our findings revealed the tumor-promoting role of ENPP2 in MM, thus providing new molecular evidence for targeting the ENPP2-LPA axis in MM therapy.

[18F](2S,4R)-4-Fluoroglutamine as a New Positron Emission Tomography Tracer in Myeloma

The high glycolytic activity of multiple myeloma (MM) cells is the rationale for use of Positron Emission Tomography (PET) with ¹⁸F-fluorodeoxyglucose ([¹⁸F]FDG) to detect both bone marrow (BM) and extramedullary disease. However, new tracers are actively searched because [¹⁸F]FDG-PET has some limitations and there is a portion of MM patients who are negative. Glutamine (Gln) addiction has been recently described as a typical metabolic feature of MM cells. Yet, the possible exploitation of Gln as a PET tracer in MM has never been assessed so far and is investigated in this study in preclinical models. Firstly, we have synthesized enantiopure (2S,4R)-4-fluoroglutamine (4-FGln) and validated it as a Gln transport analogue in human MM cell lines, comparing its uptake with that of ³H-labelled Gln. We then radiosynthesized [¹⁸F]4-FGln, tested its uptake in two different in vivo murine MM models, and checked the effect of Bortezomib, a proteasome inhibitor currently used in the treatment of MM. Both [¹⁸F]4-FGln and [¹⁸F]FDG clearly identified the spleen as site of MM cell colonization in C57BL/6 mice, challenged with syngeneic Vk12598 cells and assessed by PET. NOD.SCID mice, subcutaneously injected with human MM JJN3 cells, showed high values of both [¹⁸F]4-FGln and [¹⁸F]FDG uptake. Bortezomib significantly reduced the uptake of both radiopharmaceuticals in comparison with vehicle at post treatment PET. However, a reduction of glutaminolytic, but not of glycolytic, tumor volume was evident in mice showing the highest response to Bortezomib. Our data indicate that [¹⁸F](2S,4R)-4-FGln is a new PET tracer in preclinical MM models, yielding a rationale to design studies in MM patients.

Clarifying the molecular mechanism of tomentosin‑induced antiproliferative and proapoptotic effects in human multiple myeloma via gene expression profile and genetic interaction network analysis

Multiple myeloma (MM) is an aggressive B cell malignancy. Substantial progress has been made in the therapeutic context for patients with MM, however it still represents an incurable disease due to drug resistance and recurrence. Development of more effective or synergistic therapeutic approaches undoubtedly represents an unmet clinical need. Tomentosin is a bioactive natural sesquiterpene lactone extracted by various plants with therapeutic properties, including anti-neoplastic effects. In the present study, the potential antitumor activity of tomentosin was evaluated on the human RPMI-8226 cell line, treated with increasing tomentosin concentration for cytotoxicity screening. The data suggested that both cell cycle arrest and cell apoptosis could explain the antiproliferative effects of tomentosin and may result in the inhibition of RPMI-8226 cell viability. To assess differentially expressed genes contributing to tomentosin activity and identify its mechanism of action, a microarray gene expression profile was performed, identifying 126 genes deregulated by tomentosin. To address the systems biology and identify how tomentosin deregulates gene expression in MM from a systems perspective, all deregulated genes were submitted to enrichment and molecular network analysis. The Protein-Protein Interaction (PPI) network analysis showed that tomentosin in human MM induced the downregulation of genes involved in several pathways known to lead immune-system processes, such as cytokine-cytokine receptor interaction, chemokine or NF-κB signaling pathway, as well as genes involved in pathways playing a central role in cellular neoplastic processes, such as growth, proliferation, migration, invasion and apoptosis. Tomentosin also induced endoplasmic reticulum stress via upregulation of cyclic AMP-dependent transcription factor ATF-4 and DNA damage-inducible transcript 3 protein genes, suggesting that in the presence of tomentosin the protective unfolded protein response signaling may induce cell apoptosis. The functional connections analysis executed using the Connectivity Map tool, suggested that the effects of tomentosin on RPMI-8226 cells might be similar to those exerted by heat shock proteins inhibitors. Taken together, these data suggested that tomentosin may be a potential drug candidate for the treatment of MM.

Phosphatidylinositol 3-kinase signaling inhibitors for treatment of multiple myeloma: From small molecules to microRNAs

Multiple myeloma is one of the most hard-to-treat cancers among blood malignancies due to the high rate of drug resistance and relapse. The researchers are trying to find more effective drugs for treatment of the disease. Hence, the use of drugs targeting signaling pathways has become a powerful weapon. Overactivation of phosphatidylinositol 3-kinase signaling pathways is frequently observed in multiple myeloma cancer cells, which increases survival, proliferation, and even drug resistance in such cells. In recent years, drugs that inhibit the mediators involved in this biological pathway have shown promising results in the treatment of multiple myeloma. In the present study, we aimed to introduce phosphatidylinositol 3-kinase signaling inhibitors which include small molecules, herbal compounds, and microRNAs.

Suppression of cancer-associated bone loss through dynamic mechanical loading

Patients afflicted with or being treated for cancer constitute a distinct and alarming subpopulation who exhibit elevated fracture risk and heightened susceptibility to developing secondary osteoporosis. Cancer cells uncouple the regulatory processes central for the adequate regulation of musculoskeletal tissue. Systemically taxing treatments to target tumors or disrupt the molecular elements driving tumor growth place considerable strain on recovery efforts. Skeletal tissue is inherently sensitive to mechanical forces, therefore attention to exercise and mechanical loading as non-pharmacological means to preserve bone during treatment and in post-treatment rehabilitative efforts have been topics of recent focus. This review discusses the dysregulation that cancers and the ensuing metabolic dysfunction that confer adverse effects on musculoskeletal tissues. Additionally, we describe foundational mechanotransduction pathways and the mechanisms by which they influence both musculoskeletal and cancerous cells. Functional and biological implications of mechanical loading at the tissue and cellular levels will be discussed, highlighting the current understanding in the field. Herein, in vitro, translational, and clinical data are summarized to consider the positive impact of exercise and low magnitude mechanical loading on tumor-bearing skeletal tissue.

Expanded natural killer cells augment the antimyeloma effect of daratumumab, bortezomib, and dexamethasone in a mouse model

The use of natural killer (NK) cells is a promising and safe immunotherapeutic approach in the field of cancer immunotherapy. However, combination treatments are required to enhance the effector functions and therapeutic efficacy of NK cells. In this study, we investigated the potential of daratumumab (Dara), bortezomib, and dexamethasone (Dvd) to augment the antitumor effects of NK cells in a multiple myeloma (MM) xenograft mouse model. NK cells were expanded and activated using the K562-OX40 ligand and membrane-bound IL-18 and IL-21 in the presence of IL-2 and IL-15 from peripheral blood mononuclear cells from MM patients. A human MM xenograft model was established using human RPMI8226-RFP-FLuc cells in NOD/SCID IL-2Rγ^null (NSG) mice. Tumor-bearing mice were divided into six treatment groups: no treatment, expanded NK cells (eNKs), Dara, Dara + eNKs, Dvd, and Dvd + eNKs. Dvd treatment strongly enhanced the cytotoxicity of eNKs by upregulating expression of NK cell activation ligands, downregulating expression of NK cell inhibitory ligands, and promoting antibody-dependent cellular cytotoxicity. The combination of eNKs with Dvd significantly prolonged mouse survival and reduced the tumor burden and serum M-protein level. Furthermore, Dvd pretreatment significantly increased eNK persistence and homing to MM sites. Our findings suggest that Dvd treatment potentiates the antimyeloma effects of NK cells expanded and activated ex vivo by modulating immune responses in MM-bearing mice.

Promoting exercise for patients with multiple myeloma: attitudes and practices of clinical haematologists

PURPOSE

To explore the attitudes and practices of clinical haematologists towards promoting physical activity (PA) and exercise for patients with multiple myeloma (MM).

METHODS

Using a quantitative cross-sectional survey, clinical haematologists reported on the perceived benefits and acceptability of PA and exercise and frequency, confidence and barriers to providing exercise advice.

RESULTS

Clinical haematologists (n=34; 68% response rate), who cumulatively treated ~340 patients with MM each week, completed the survey. Almost all (97%) agreed that PA was important, with benefits for quality of life, activities of daily living, mental health and fatigue. Whilst 88% discussed PA at least occasionally with their patients, approximately two-thirds were not confident advising specific exercises (68%) or identifying PA resources (62%). Despite this, 44% never referred patients to exercise professionals, with 18% only doing so if the patient asked. Over half did not recommend exercise when patients had spine fractures or were physically unwell. No differences were observed in individual factors (age, gender, practice type and own PA participation) and promotion of PA.

CONCLUSIONS

Clinical haematologists perceive PA as important, but lack confidence on what exercise/s to recommend and if exercise is appropriate for specific disease complications. They tend to not refer patients to exercise professionals.

IMPLICATIONS FOR CANCER SURVIVORS

Patients with MM often suffer from symptoms and toxicities that may be alleviated through PA. However, PA participation rates are low. Support for clinical haematologists for when and how to discuss exercise, and clearer referral pathways to exercise professionals may improve PA uptake and hence ensure access to optimal care, thereby improving patient outcomes.

Promotion of Bone Lesions Through the Myeloma Integrin α6-Mediated Osteolytic Signaling

Osteolytic destruction is a hallmark of multiple myeloma and impairs myeloma patients' quality of life. However, the molecular mechanism underlying the pathogenesis of myeloma-associated bone disease remains unclear. In this study, we demonstrate the role of myeloma cell-expressed integrin α6 in bone. Integrin α6 binds to laminin 8 and epidermal growth factor receptor on mesenchymal stem cells (MSCs) to form a trimer complex and upregulates the secretion of osteolytic cytokines from both myeloma cells and MSCs, leading to enhanced bone resorption and reduced bone formation. Thus, this study elucidates an important mechanism for myeloma-induced bone lesions and implicates that targeting integrin α6 may be a viable approach for bone healing in myeloma patients.

Factors Associated with Dose Modification of Lenalidomide Plus Dexamethasone Therapy in Multiple Myeloma

Long-term combination treatment with lenalidomide and low-dose dexamethasone is important to achieve a curative effect in patients with multiple myeloma (MM). In this study, the plasma concentration of lenalidomide was measured at 3 h after oral administration, when the drug is in the elimination phase and can be easily measured in outpatients, to identify factors that may lead to the discontinuation of this combination therapy. Patients were assigned to continuation or discontinuation of therapy groups, and the baseline characteristics of patients, lenalidomide concentration, and concentration/dose (C/D) ratios reflecting oral clearance were compared between the two groups. The efficacy and severity of adverse events were also compared. The results showed that patients who discontinued or modified treatment had low plasma concentrations of lenalidomide and C/D ratios, indicating high oral clearance of lenalidomide. The estimated creatinine clearance rate was negatively correlated with the C/D ratio. The plasma concentrations of lenalidomide were independent from kidney function and differed significantly among patients. Taken together, the results indicate that low plasma concentrations of lenalidomide and low C/D ratios may lead to discontinuation of combination therapy in patients with MM. This suggests that early measurement of lenalidomide plasma continuation would help to prevent discontinuation of therapy or a delay in modifying the dose of lenalidomide.

Role of Osteocytes in Cancer Progression in the Bone and the Associated Skeletal Disease

PURPOSE OF REVIEW

The goal of this manuscript is to review the current knowledge on the role of osteocytes in cancer in the bone, discuss the potential of osteocytes as a therapeutic target, and propose future research needed to understand the crosstalk between cancer cells and osteocytes in the tumor niche.

RECENT FINDINGS

Numerous studies have established that cancer cells manipulate osteocytes to facilitate invasion and tumor progression in bone. Moreover, cancer cells dysregulate osteocyte function to disrupt physiological bone remodeling, leading to the development of bone disease. Targeting osteocytes and their derived factors has proven to effectively interfere with the progression of cancer in the bone and the associated bone disease. Osteocytes communicate with cancer cells and are also part of the vicious cycle of cancer in the bone. Additional studies investigating the role of osteocytes on metastases to the bone and the development of drug resistance are needed.

The multifunctional role of Notch signaling in multiple myeloma

Multiple myeloma (MM) is a hematologic cancer characterized by uncontrolled growth of malignant plasma cells in the bone marrow and currently is incurable. The bone marrow microenvironment plays a critical role in MM. MM cells reside in specialized niches where they interact with multiple marrow cell types, transforming the bone/bone marrow compartment into an ideal microenvironment for the migration, proliferation, and survival of MM cells. In addition, MM cells interact with bone cells to stimulate bone destruction and promote the development of bone lesions that rarely heal. In this review, we discuss how Notch signals facilitate the communication between adjacent MM cells and between MM cells and bone/bone marrow cells and shape the microenvironment to favor MM progression and bone disease. We also address the potential and therapeutic approaches used to target Notch signaling in MM.

O-GlcNAcylation homeostasis controlled by calcium influx channels regulates multiple myeloma dissemination

BACKGROUND

Multiple myeloma (MM) cell motility is a critical step during MM dissemination throughout the body, but how it is regulated remains largely unknown. As hypercalcemia is an important clinical feature of MM, high calcium (Ca2+) and altered Ca2+ signaling could be a key contributing factor to the pathological process.

METHODS

Bioinformatics analyses were employed to assess the clinical significance of Ca2+ influx channels in clinical specimens of smoldering and symptomatic MM. Functional and regulatory roles of influx channels and downstream signaling in MM cell migration and invasion were conducted and experimental MM dissemination was examined in a xenograft mouse model using in vivo live imaging and engraftment analysis.

RESULTS

Inhibition of TRPM7, ORAI1, and STIM1 influx channels, which are highly expressed in MM patients, and subsequent blockage of Ca2+ influx by CRISPR/Cas9 and small molecule inhibitors, effectively inhibit MM cell migration and invasion, and attenuate the experimental MM dissemination. Mechanistic studies reveal a nutrient sensor O-GlcNAcylation as a downstream regulator of Ca2+ influx that specifically targets cell adhesion molecules. Hyper-O-GlcNAcylation following the inhibition of Ca2+ influx channels induces integrin α4 and integrin β7 downregulation via ubiquitin-proteasomal degradation and represses the aggressive MM phenotype.

CONCLUSIONS

Our findings unveil a novel regulatory mechanism of MM cell motility via Ca2+ influx/O-GlcNAcylation axis that directly targets integrin α4 and integrin β7, providing mechanistic insights into the pathogenesis and progression of MM and demonstrating potential predictive biomarkers and therapeutic targets for advanced MM.

Oncolytic Virotherapy and Microenvironment in Multiple Myeloma

Multiple myeloma (MM) is a hematologic malignancy characterized by the accumulation of bone marrow (BM) clonal plasma cells, which are strictly dependent on the microenvironment. Despite the improvement of MM survival with the use of new drugs, MM patients still relapse and become always refractory to the treatment. The development of new therapeutic strategies targeting both tumor and microenvironment cells are necessary. Oncolytic virotherapy represent a promising approach in cancer treatment due to tumor-specific oncolysis and activation of the immune system. Different types of human viruses were checked in preclinical MM models, and the use of several viruses are currently investigated in clinical trials in MM patients. More recently, the use of alternative non-human viruses has been also highlighted in preclinical studies. This strategy could avoid the antiviral immune response of the patients against human viruses due to vaccination or natural infections, which could invalid the efficiency of virotherapy approach. In this review, we explored the effects of the main oncolytic viruses, which act through both direct and indirect mechanisms targeting myeloma and microenvironment cells inducing an anti-MM response. The efficacy of the oncolytic virus-therapy in combination with other anti-MM drugs targeting the microenvironment has been also discussed.

Denosumab compared with zoledronic acid on PFS in multiple myeloma: exploratory results of an international phase 3 study

An exploratory end point from a recent trial in patients with newly diagnosed multiple myeloma showed that median progression-free survival (PFS) was increased by 10.7 months with denosumab vs zoledronic acid. We performed additional analyses to identify factors that may have contributed to the favorable PFS with denosumab. Ad hoc analyses were performed for patients intending to undergo autologous stem cell transplantation (ASCT; ASCT intent), not intending to undergo ASCT (ASCT no intent), and intent-to-treat according to age (<70 or ≥70 years) and baseline renal function (≤60 mL/min or >60 mL/min creatinine clearance [CrCl]). Of 1718 patients, 930 (54.1%) were in the ASCT-intent subgroup, and 788 (45.9%) were in the ASCT-no-intent subgroup. In the ASCT-intent subgroup, frontline triplet (median PFS, not estimable vs 35.7 months; hazard ratio [HR] [95% confidence interval (CI)], 0.65 [0.47-0.90]; descriptive P = .009) or bortezomib-only (median PFS, not estimable vs not estimable; HR [95% CI], 0.61 [0.39-0.95]; descriptive P = .029) induction regimens demonstrated the strongest PFS benefit favoring denosumab vs zoledronic acid. In the ASCT-no-intent subgroup, no benefit with denosumab vs zoledronic acid was observed. PFS favored denosumab vs zoledronic acid in patients with CrCl >60 mL/min and in patients <70 years old, but no difference was observed in patients with CrCl ≤60 mL/min or patients ≥70 years old. The PFS difference observed with denosumab is one of the notable benefits reported in newly diagnosed multiple myeloma and was most pronounced in patients intending to undergo ASCT and those who received proteasome inhibitor (PI)-based triplet regimens. This study was registered at www.clinicaltrials.gov as #NCT01345019.

Extracellular vesicles (EVs): What we know of the mesmerizing roles of these tiny vesicles in hematological malignancies?

Cancer is a complex disease in which a bidirectional collaboration between malignant cells and surrounding microenvironment creates an appropriate platform which ultimately facilitates the progression of the disease. The discovery of extracellular vesicles (EVs) was a turning point in the modern era of cancer biology, as their importance in human malignancies has set the stage to widen research interest in the field of cell-to-cell communication. The implication in short- and long-distance interaction via horizontally transfer of cellular components, ranging from non-coding RNAs to functional proteins, as well as stimulating target cells receptors by the means of ligands anchored on their membrane endows these "tiny vesicles with giant impacts" with incredible potential to re-educate normal tissues, and thus, to re-shape the surrounding niche. In this review, we highlight the pathogenic roles of EVs in human cancers, with an extensive focus on the recent advances in hematological malignancies.

Macrophages in multiple myeloma: key roles and therapeutic strategies

Macrophages are a vital component of the tumour microenvironment and crucial mediators of tumour progression. In the last decade, significant strides have been made in understanding the crucial functional roles played by macrophages in the development of the plasma cell (PC) malignancy, multiple myeloma (MM). Whilst the interaction between MM PC and stromal cells within the bone marrow (BM) microenvironment has been extensively studied, we are only just starting to appreciate the multifaceted roles played by macrophages in disease progression. Accumulating evidence demonstrates that macrophage infiltration is associated with poor overall survival in MM. Indeed, macrophages influence numerous pathways critical for the initiation and progression of MM, including homing of malignant cells to BM, tumour cell growth and survival, drug resistance, angiogenesis and immune suppression. As such, therapeutic strategies aimed at targeting macrophages within the BM niche have promise in the clinical setting. This review will discuss the functions elicited by macrophages throughout different stages of MM and provide a comprehensive evaluation of potential macrophage-targeted therapies.

Management of acute spinal cord compression in multiple myeloma

Spinal cord compression (SCC) is a devastating complication of multiple myeloma and has the potential to cause loss of neurological function. The common symptoms of SCC are back pain, motor weakness, and sensory change. Once diagnosed, the patient should be managed as soon as possible to prevent permanent loss of neurological function. Currently, there have been a number of studies describing the mechanism and management experience of SCC in patients with myeloma. The clinical features, diagnostic strategies, and the roles of different therapeutic options are herein reviewed.

Association of RANK and RANKL gene polymorphism with survival and calcium levels in multiple myeloma

Multiple myeloma (MM) is a heterogeneous bone marrow cancer characterized by proliferation of malignant plasma cells in the bone marrow. One of its major symptoms are hypercalcaemia and bone lesions, which may result in pathologic bone fractures. Receptor activator for nuclear factor κB (RANK) and its ligand, RANKL, are part of an activation pathway for osteoclasts and are thus responsible for bone resorption. Furthermore, RANKL expression is increased in multiple myeloma. In the present study, we investigated the role of single nucleotide polymorphisms (SNPs) in the genes coding for RANK (rs1805034, rs8086340), RANKL (rs7325635, rs7988338), and TACI (rs34562254), a receptor for osteoclast-derived pro-survival factors. The study involved 222 patients and 222 healthy individuals, and the analysis included disease susceptibility, survival, bone lesions, calcium levels, and vascular endothelial growth factor levels. Patients with allele RANK rs1805034 C had higher survival (p = .003). This relationship was especially evident in women (p = .006). Furthermore, allele rs1805034 C was associated with slightly lower median age at diagnosis (64.0 vs. 65.5, p = .008). Allele RANKL rs7325635 A correlated with lower progression-free survival (p = .027), and with lack of early progression (p = .023). Additionally, women with allele rs7325635 G were found to have higher calcium blood concentration (p = .040). Allele TACI rs34562254 A was more common in MM patients in more advanced stages (II and III stage International Staging System) at diagnosis (p = .017), and the SNP showed a slight trend towards association in a multivariate analysis (p = .084). Taken together, our results suggest that RANK rs1805034 and RANKL rs7325635 may have a role in MM development and progression.

ER stress arm XBP1s plays a pivotal role in proteasome inhibition-induced bone formation

BACKGROUND

Bone destruction is a hallmark of multiple myeloma (MM). It has been reported that proteasome inhibitors (PIs) can reduce bone resorption and increase bone formation in MM patients, but the underlying mechanisms remain unclear.

METHODS

Mesenchymal stem cells (MSCs) were treated with various doses of PIs, and the effects of bortezomib or carfilzomib on endoplasmic reticulum (ER) stress signaling pathways were analyzed by western blotting and real-time PCR. Alizarin red S (ARS) and alkaline phosphatase (ALP) staining were used to determine the osteogenic differentiation in vitro. Specific inhibitors targeting different ER stress signaling and a Tet-on inducible overexpressing system were used to validate the roles of key ER stress components in regulating osteogenic differentiation of MSCs. Chromatin immunoprecipitation (ChIP) assay was used to evaluate transcription factor-promoter interaction. MicroCT was applied to measure the microarchitecture of bone in model mice in vivo.

RESULTS

We found that both PERK-ATF4 and IRE1α-XBP1s ER stress branches are activated during PI-induced osteogenic differentiation. Inhibition of ATF4 or XBP1s signaling can significantly impair PI-induced osteogenic differentiation. Furthermore, we demonstrated that XBP1s can transcriptionally upregulate ATF4 expression and overexpressing XBP1s can induce the expression of ATF4 and other osteogenic differentiation-related genes and therefore drive osteoblast differentiation. MicroCT analysis further demonstrated that inhibition of XBP1s can strikingly abolish bortezomib-induced bone formation in mouse.

CONCLUSIONS

These results demonstrated that XBP1s is a master regulator of PI-induced osteoblast differentiation. Activation of IRE1α-XBP1s ER stress signaling can promote osteogenesis, thus providing a novel strategy for the treatment of myeloma bone disease.