Pathogenesis of myeloma

Toll-like receptor 1/2 activation reduces immunoglobulin free light chain production by multiple myeloma cells in the context of bone marrow stromal cells and fibronectin

Toll-like receptor (TLRs) activation in multiple myeloma (MM) cells induces heterogeneous functional responses including cell growth and proliferation, survival or apoptosis. These effects have been suggested to be partly due to increase in secretion of cytokines such as IL-6 or IFNα among others from MM cells following TLR activation. However, whether triggering of these receptors also modulates production of immunoglobulin free light chains (FLCs), which largely contribute to MM pathology, has not been investigated in MM cells before. This study explored the effect of TLR1/2 ligand (Pam3CSK4) alone or combined with bortezomib (BTZ) on production of FLCs in human myeloma cell lines, L363, OPM-2, U266 and NCI-H929. It also investigated the above effect when MM cells were exposed to bone marrow stromal cells (BMSCs) or fibronectin (FN). Adhesion to BMSCs or FN increased secretion of FLC in MM cells. Pam3CSK4 decreased FLC production, and this effect was enhanced in combination with BTZ but attenuated when MM cells adhered to BMSCs or FN. The findings of this study imply that activation of TLR1/2 downregulates FLC production in MM cells even in the context of bone marrow microenvironment components and suggest that targeting some TLRs such as TLR1/2 might have therapeutic potential.

Recent advances in targeted drug delivery systems for multiple myeloma

Despite significant therapeutic advances, multiple myeloma (MM) remains a challenging, incurable, hematological malignancy. The efficacy of traditional chemotherapy and currently available anti-MM agents is in part limited by their adverse effects, which restrict their therapeutic potential. Nanotherapeutics is an emerging field of cancer therapy that can overcome the biological and chemical barriers of existing anticancer drugs. This review presents an overview of recent advancements in nanoparticle- and immunotherapy-based drug delivery systems for MM treatment. It further delves into the targeting strategies, mechanism of controlled drug release, and challenges associated with the development of drug delivery systems for the treatment of MM.

Theoretical Model for In Vivo Induction of Chemotherapy Sensitization Using miRNA Packaged in Distinct Layered Liposomes

Resistance to chemotherapy is a problem of major social and economic importance, when looking at factors like the decrease in life expectancy, the associated therapeutic costs, and a significant number of cancers that resist current chemotherapy. The development of chemotherapeutics for all theoretically possible tumor variants is an approach that requires unreasonable resources. We propose a theoretical model that serves the purpose of overcoming resistance to chemotherapeutic agents used in cancer therapy. The model describes a gene delivery system based on liposomes, which are optically guided to the tumor's location. The main aim of the gene delivery system is inhibiting the activity of enzymes involved in drug metabolism, hence offering the opportunity to use inexpensive chemotherapeutics that are already on the market. This model will reduce the costs of chemotherapy and will assure a positive outcome for patients.

Unmasking Infection Risks in Multiple Myeloma: Insights from a Retrospective Analysis

Multiple myeloma (MM) has witnessed significant therapeutic advancements through the introduction of proteasome inhibitors and immunomodulators, leading to improved treatment outcomes. However, infections remain a formidable challenge for MM patients. The objective of our research is to investigate the factors that can forecast infection risk in MM patients. In pursuit of this, we conducted a thorough retrospective examination of medical records from Kidwai Memorial Institute of Oncology, Bangalore, involving 145 MM patients. Out of the 145 patients analyzed, almost half (47.5%; n = 69) encountered at least one infection during the course of their disease. Respiratory-related infections were the most prevalent (76.2%), followed by urinary tract infections (10%) and instances of diarrhea (8.8%). Notably, gram-positive bacteria constituted the majority of identified causative organisms, accounting for 48.2% of isolated pathogens, while gram-negative bacteria comprised 37.9% of the isolated organisms. Most infections were observed either at the time of presentation or during the first month (40.5%). Overall mortality during the study period was 4.8% (n = 7). Infections contributed to 57.1% (n = 4 out of 7 deaths) of the mortality. Moreover, patients in advanced stages exhibited an elevated risk of infection at presentation. Infections remain a major cause of morbidity and mortality in patients with MM. Nearly half of MM patients experience an episode of infection during treatment.Gram-positive bacteria are the most common pathogens, with respiratory infections being the most common foci. Prompt identification and treatment of infections is essential, but can be challenging due to atypical or absent symptoms. Antibacterial prophylaxis is an important preventive strategy, but further research is needed to develop innovative approaches to infection prevention and targeted therapeutic interventions. We must strive to develop innovative approaches to infection prevention in MM patients. Also we need to advance our understanding of the interplay between infections and MM to improve quality of care and outcomes for these individuals. By addressing these challenges, we can aspire to offer MM patients a brighter and healthier future.

Tetrahydroisoquinoline reduces angiogenesis by interacting myeloma cells with HUVECs mediated by extracellular vesicles

Multiple myeloma (MM) is a neoplastic condition resulting from the uncontrolled expansion of B-cell-derived plasma cells. The importance of angiogenesis in MM development has also been demonstrated. Extracellular vesicles (EVs) have vital functions in interactions between neighboring cells, such as angiogenesis. The objective of this in vitro study was to examine the transfection and angiogenesis effects of MM-EVs on endothelial cells (ECs) upon treatment with Tetrahydroisoquinoline (THIQ) as a bioactive organic compound derivative from isoquinoline. Following treatment of multiple myeloma cells (U266) with THIQ, MM-EVs were harvested and transmigrated to human umbilical vein endothelial cells (HUVEC) in a co-culture model. EVs transmigration was traced by flow cytometry. Correspondingly, the expression of angiogenic genes and/or proteins in U266 cells and HUVECs was measured by RT-PCR and ELISA methods. Likewise, the proliferation and migration of HUVECs treated with THIQ-treated MM-EVs were visualized and estimated by performing both tube formation and scratch wound healing methods. Surprisingly, the anti-angiogenic effect of THIQ-treated MM-EVs was evident by the decreased expression of CD34, VEGFR2, and IL-6 at the mRNA and/or protein levels after internalization of MM-EVs in HUVEC. Finally, tube formation and scratch wound healing experiments showed inhibition of HUVEC cell proliferation and migration by THIQ-treated MM-EVs compared to control MM-EVs. MM-EVs derived from THIQ-treated myeloma cells (U266) inhibited angiogenesis in HUVECs. This phenomenon is coordinated by the internalized THIQ-treated MM-EVs in HUVECs, and ultimately the reduction of angiogenic factors and inhibition of tube formation and scratch wound healing.

Isatuximab with pomalidomide-dexamethasone in relapsed/refractory multiple myeloma: post-marketing surveillance in Japan

This post-marketing surveillance assessed the safety and effectiveness of isatuximab plus pomalidomide and dexamethasone (Isa-Pd) for relapsed or refractory multiple myeloma (RRMM) during real-world use in Japan. Data from 211 individuals with RRMM treated with Isa-Pd in Japan between October 2020 and October 2021 were collected, with follow-up for up to 12 months after initiation of Isa-Pd or until treatment discontinuation. The incidence of adverse drug reactions (ADRs), ADRs of special interest (infusion reactions, bone marrow suppression, infections, cardiac disorders, other ADRs of Grade ≥ 3), and serious ADRs was assessed. Best overall response and overall response rate (ORR) were determined. In the safety analysis set (n = 120), ADR incidence was 57.5%. Most ADRs were hematologic, and serious ADRs occurred in 28.3%. Bone marrow suppression occurred in 46.7% of participants (19.2% serious), infusion reactions in 18.3% (6.7% serious), infections in 11.7% (8.3% serious), and a serious cardiac disorder in one participant; other Grade ≥ 3 ADRs were reported in 3.3% (1.7% serious). In the effectiveness analysis set (n = 108), the most common best overall response was very good partial response (24.1%), and ORR was 51.9%. These findings support the safety and effectiveness of Isa-Pd for RRMM in real-life settings in Japan.

The interplay between microRNAs and Nrf2 signaling in human cancers

MicroRNAs (miRNAs), as a class of nonprotein-coding RNAs, post-transcriptionally regulate the expression of target genes by base pairing to 3'-untranslated regions (3'-UTRs). Nuclear factor E2-related factor 2 (Nrf2) has been identified as a critical component of the antioxidant defense mechanism. Dysregulation is associated with chemoresistance and radioresistance in cancerous cells. MiRNA-mediated regulation of the Nrf2 signaling pathway has been shown to have important implications for the development of various cancers. In this article, we review the roles of miRNAs as regulators of the Nrf2 pathway in different human cancers. Ras-associated binding (Rab) proteins have an essential role regulation of vesicle transport, as well as oncogenic functions in preventing chemotherapy efficacy and cancer development. More importantly, increased evidence indicated that the interaction between miRNAs and Rabs has been determined to play critical roles in cancer therapy. However, the significant limitations in using miRNAs for therapeutic applications include cross-targeting and instability of miRNAs. The detailed aspect of the interaction of miRNAs and Rabs is not clearly understood. In the current review, we highlighted the involvement of these molecules as regulators of the Nrf2 pathway in cancer pathogenesis. Potential methods and several obstacles in developing miRNAs as an anticancer therapy are also mentioned.

Highlighting the role of long non-coding RNA (LncRNA) in multiple myeloma (MM) pathogenesis and response to therapy

Transcripts longer than 200 nucleotides that are not translated into proteins are known as long non-coding RNAs, or lncRNAs. Now, they are becoming more significant as important regulators of gene expression, and as a result, of many biological processes in both healthy and pathological circumstances, such as blood malignancies. Through controlling alternative splicing, transcription, and translation at the post-transcriptional level, lncRNAs have an impact on the expression of genes. In multiple myeloma (MM), the majority of lncRNAs is elevated and promotes the proliferation, adhesion, drug resistance and invasion of MM cells by blocking apoptosis and altering the tumor microenvironment (TME). To control mRNA splicing, stability, and translation, they either directly attach to the target mRNA or transfer RNA-binding proteins (RBPs). By expressing certain miRNA-binding sites that function as competitive endogenous RNAs (ceRNAs), most lncRNAs mimic the actions of miRNAs. Here, we highlight lncRNAs role in the MM pathogenesis with emphasize on their capacity to control the molecular mechanisms known as "hallmarks of cancer," which permit earlier tumor initiation and progression and malignant cell transformation.

Once-weekly versus twice-weekly bortezomib in newly diagnosed multiple myeloma: a real-world analysis

Induction regimens for multiple myeloma (MM) commonly include bortezomib, which has typically been administered twice weekly despite studies demonstrating comparable efficacy and less peripheral neuropathy (PN) with once-weekly bortezomib. We aimed to analyze the real-world prevalence and efficacy of once-weekly versus twice-weekly bortezomib regimens in newly diagnosed MM. We analyzed 2497 US patients aged 18-70 years treated with commercial first-line bortezomib using nationwide Flatiron Health electronic health record-derived data, including 910 (36.4%) patients who received twice-weekly and 1522 (63.2%) who received once-weekly bortezomib. Once-weekly bortezomib use increased over time, from 57.7% in 2017 to 73.1% in 2022. Multivariate analysis identified worsened performance status and more recent year of diagnosis with higher odds of receiving once-weekly bortezomib. Real-world progression-free survival (median 37.2 months with once-weekly versus 39.6 months with twice-weekly, p = 0.906) and overall survival (medians not reached in either cohort, p = 0.800) were comparable. PN rates were higher in patients receiving twice-weekly bortezomib (34.7% versus 18.5%, p < 0.001). In conclusion, once-weekly bortezomib is clearly associated with similar efficacy and fewer toxicities compared to twice-weekly bortezomib. Our findings support once-weekly bortezomib as a standard-of-care regimen for newly diagnosed patients with MM.

CDK6 protein expression is associated with disease progression and treatment resistance in multiple myeloma

Multiple myeloma (MM) is a heterogeneous malignancy of plasma cells. Despite improvement in the prognosis of MM patients after the introduction of many new drugs in the past decades, MM remains incurable since most patients become treatment-resistant. Cyclin-dependent kinase 6 (CDK6) is activated in many types of cancer and has been associated with drug resistance in MM. However, its association with disease stage, genetic alterations, and outcome has not been systematically investigated in large cohorts. Here, we analyzed CDK6 expression using immunohistochemistry in 203 formalin-fixed paraffin-embedded samples of 146 patients and four healthy individuals. We found that 61.5% of all MM specimens express CDK6 at various levels. CDK6 expression increased with the progression of disease with a median of 0% of CDK6-positive plasma cells in monoclonal gammopathy of undetermined significance (MGUS) (n = 10) to 30% in newly diagnosed MM (n = 78) and up to 70% in relapsed cases (n = 55). The highest median CDK6 was observed in extramedullary myeloma (n = 12), a highly aggressive manifestation of MM. Longitudinal analyses revealed that CDK6 is significantly increased in lenalidomide-treated patients but not in those who did not receive lenalidomide. Furthermore, we observed that patients who underwent lenalidomide-comprising induction therapy had significantly shorter progression-free survival when their samples were CDK6 positive. These data support that CDK6 protein expression is a marker for aggressive and drug-resistant disease and describes a potential drug target in MM.

Optimal timing and drug combination of selinexor in multiple myeloma: a systematic review and meta-analysis

OBJECTIVES

Multiple myeloma (MM) remains an incurable disease despite advances in treatment options. Recently, selinexor has shown promising efficacy for relapsed/refractory multiple myeloma (RRMM), whereas its optimal timing and drug combination remain unclear. In order to assess the various regimens that incorporate selinexor, a systematic review and meta-analysis was conducted.

METHODS

Clinical trials and real-world studies involving MM patients treated with selinexor were included. Pooled risk ratio (RR) was calculated to compare the rates, along with a 95% confidence interval (CI) and concurrent p-value assessment. A random-effects model was employed to provide a more conservative evaluation.

RESULTS

A total of 16 studies enrolling 817 patients were reviewed. The usage of selinexor as the fifth-line or prior therapy achieved a higher objective response rate (ORR) (65.9% versus 23.4%, p < 0.01) and longer pooled progression-free survival (PFS) (median: 12.5 months versus 2.9 months, p < 0.01) than those after the fifth-line usage. In addition, early usage also resulted in a consistent trend of pooled overall survival (median: 22.7 months versus 8.9 months, p = 0.26), compared with post-fifth-line usage. Selinexor and dexamethasone (Xd) plus either protease inhibitors (PIs) or immunomodulatory drugs (IMiDs) achieved better ORRs than the Xd-only regimen for RRMM, with ORRs of 56.1%, 52.5% and 24.6%, respectively (p < 0.01).

CONCLUSION

In conclusion, using selinexor as the fifth-line or prior therapy had a beneficial impact on RRMM. The regimen of Xd plus PIs or IMiDs was recommended.

Complete miRNA-15/16 loss in mice promotes hematopoietic progenitor expansion and a myeloid-biased hyperproliferative state

Dysregulated apoptosis and proliferation are fundamental properties of cancer, and microRNAs (miRNA) are critical regulators of these processes. Loss of miR-15a/16-1 at chromosome 13q14 is the most common genomic aberration in chronic lymphocytic leukemia (CLL). Correspondingly, the deletion of either murine miR-15a/16-1 or miR-15b/16-2 locus in mice is linked to B cell lymphoproliferative malignancies. However, unexpectedly, when both miR-15/16 clusters are eliminated, most double knockout (DKO) mice develop acute myeloid leukemia (AML). Moreover, in patients with CLL, significantly reduced expression of miR-15a, miR-15b, and miR-16 associates with progression of myelodysplastic syndrome to AML, as well as blast crisis in chronic myeloid leukemia. Thus, the miR-15/16 clusters have a biological relevance for myeloid neoplasms. Here, we demonstrate that the myeloproliferative phenotype in DKO mice correlates with an increase of hematopoietic stem and progenitor cells (HSPC) early in life. Using single-cell transcriptomic analyses, we presented the molecular underpinning of increased myeloid output in the HSPC of DKO mice with gene signatures suggestive of dysregulated hematopoiesis, metabolic activities, and cell cycle stages. Functionally, we found that multipotent progenitors (MPP) of DKO mice have increased self-renewing capacities and give rise to significantly more progeny in the granulocytic compartment. Moreover, a unique transcriptomic signature of DKO MPP correlates with poor outcome in patients with AML. Together, these data point to a unique regulatory role for miR-15/16 during the early stages of hematopoiesis and to a potentially useful biomarker for the pathogenesis of myeloid neoplasms.

Updates in Plasma Cell Dyscrasias and Related Monoclonal Immunoglobulin-Mediated Renal Disease

Pathogenic roles of monoclonal immunoglobulins in kidney disease have been attributed previously to malignant plasma cell and lymphoproliferative disorders such as multiple myeloma, lymphoplasmacytic lymphoma, chronic lymphocytic leukemia, or amyloid light chain amyloidosis. Improved technology, advancements in molecular diagnostics, and highly sensitive imaging techniques have established the need to redefine monoclonal gammopathies and the kidney disorders that are associated with monoclonal immunoglobulins regardless of tumor burden. This has led to the establishment of monoclonal gammopathy with renal significance (MGRS). MGRS was defined by the International Kidney and Monoclonal Gammopathy Research Group in 2012 as a clonal proliferative disorder that produces a nephrotoxic monoclonal immunoglobulin and does not meet previously defined hematological criteria for treatment of a specific malignancy. MGRS encompasses a wide array of pathologies with knowledge surrounding its incidence, prognosis, and management continuously increasing. This review examines the current evidence on the diagnosis, prognosis, pathogenesis, and therapy of plasma cell dyscrasias and related MGRS.

Computational modeling of multiple myeloma interactions with resident bone marrow cells

The interaction of multiple myeloma with bone marrow resident cells plays a key role in tumor progression and the development of drug resistance. The tumor cell response involves contact-mediated and paracrine interactions. The heterogeneity of myeloma cells and bone marrow cells makes it difficult to reproduce this environment in in-vitro experiments. The use of in-silico established tools can help to understand these complex problems. In this article, we present a computational model based on the finite element method to define the interactions of multiple myeloma cells with resident bone marrow cells. This model includes cell migration, which is controlled by stress-strain equilibrium, and cell processes such as proliferation, differentiation, and apoptosis. A series of computational experiments were performed to validate the proposed model. Cell proliferation by the growth factor IGF-1 is studied for different concentrations ranging from 0-10 ng/mL. Cell motility is studied for different concentrations of VEGF and fibronectin in the range of 0-100 ng/mL. Finally, cells were simulated under a combination of IGF-1 and VEGF stimuli whose concentrations are considered to be dependent on the cancer-associated fibroblasts in the extracellular matrix. Results show a good agreement with previous in-vitro results. Multiple myeloma growth and migration are shown to correlate linearly to the IGF-1 stimuli. These stimuli are coupled with the mechanical environment, which also improves cell growth. Moreover, cell migration depends on the fiber and VEGF concentration in the extracellular matrix. Finally, our computational model shows myeloma cells trigger mesenchymal stem cells to differentiate into cancer-associated fibroblasts, in a dose-dependent manner.

Drug Resistance: The Role of Exosomal miRNA in the Microenvironment of Hematopoietic Tumors

Extracellular vesicles (EVs), including exosomes, have an important role thanks to their ability to communicate and exchange information between tumor cells and the tumor microenvironment (TME), and have also been associated with communicating anti-cancer drug resistance (DR). The increase in proliferation of cancer cells alters oxygen levels, which causes hypoxia and results in a release of exosomes by the cancer cells. In this review, the results of studies examining the role of exosomal miRNA in DR, and their mechanism, are discussed in detail in hematological tumors: leukemia, lymphoma, and multiple myeloma. In conclusion, we underline the exosome's function as a possible drug delivery vehicle by understanding its cargo. Engineered exosomes can be used to be more specific for personalized therapy.

Synergistically Anti-Multiple Myeloma Effects: Flavonoid, Non-Flavonoid Polyphenols, and Bortezomib

Multiple myeloma (MM) is a clonal plasma cell tumor originating from a post-mitotic lymphoid B-cell lineage. Bortezomib(BTZ), a first-generation protease inhibitor, has increased overall survival, progression-free survival, and remission rates in patients with MM since its clinical approval in 2003. However, the use of BTZ is challenged by the malignant features of MM and drug resistance. Polyphenols, classified into flavonoid and non-flavonoid polyphenols, have potential health-promoting activities, including anti-cancer. Previous preclinical studies have demonstrated the anti-MM potential of some dietary polyphenols. Therefore, these dietary polyphenols have the potential to be alternative therapies in anti-MM treatment regimens. This systematic review examines the synergistic effects of flavonoids and non-flavonoid polyphenols on the anti-MM impacts of BTZ. Preclinical studies on flavonoids and non-flavonoid polyphenols-BTZ synergism in MM were collected from PubMed, Web of Science, and Embase published between 2008 and 2020. 19 valid preclinical studies (Published from 2008 to 2020) were included in this systematic review. These studies demonstrated that eight flavonoids (icariin, icariside II, (-)-epigallocatechin-3-gallate, scutellarein, wogonin, morin, formononetin, daidzin), one plant extract rich in flavonoids (Punica granatum juice) and four non-flavonoid polyphenols (silibinin, resveratrol, curcumin, caffeic acid) synergistically enhanced the anti-MM effect of BTZ. These synergistic effects are mediated through the regulation of cellular signaling pathways associated with proliferation, apoptosis, and drug resistance. Given the above, flavonoids and non-flavonoid polyphenols can benefit MM patients by overcoming the challenges faced in BTZ treatment. Despite the positive nature of this preclinical evidence, some additional investigations are still needed before proceeding with clinical studies. For this purpose, we conclude by providing some suggestions for future research directions.

Characteristics and clinical outcome of high-risk multiple myeloma patients in Korea (KMM 1805)

Optimal treatments for multiple myeloma (MM) patients with high-risk cytogenetics must be determined, but subgroup features are not well-defined. We used real-world data from the Korean Myeloma Registry (KMR) to analyze the characteristics and clinical outcomes of newly diagnosed MM patients with ≥ 1 high-risk cytogenetic abnormality: Group 1: t(4;14) or t(14;16); Group 2: del(17p); Group 3: t(4;14)/del(17p) or t(14;16)/del(17p). Overall, 347 high-risk patients were identified (males, 48.7%; median age, 63 years). Median progression-free survival (PFS) and overall survival (OS) were 19.0 months (95% CI 17.0-20.0) and 50.0 months (95% CI 37.0-61.0), respectively. PFS (p = 0.047) and OS (p = 0.020) differed significantly between groups. After stratification by transplant eligibility, PFS and OS were significantly poorer in Group 3 among transplant-eligible patients, and even poorer in those with gain(1q). Patients stratified by cytogenetic abnormality and revised International Staging System (R-ISS) had significantly different PFS (p < 0.001) and OS (p = 0.003), with the worst survival in R-ISS III/Group 3 (median OS 21.0 months). Higher number of high-risk cytogenetic abnormalities was a negative prognostic marker for PFS and OS (p < 0.001). Real-world KMR data showed that risk factors for poor prognosis of MM patients included del(17p), R-ISS stage, and number of cytogenetic abnormalities.

Enrichment-Free Single-Cell Detection and Morphogenomic Profiling of Myeloma Patient Samples to Delineate Circulating Rare Plasma Cell Clones

Multiple myeloma is an incurable malignancy that initiates from a bone marrow resident clonal plasma cell and acquires successive mutational changes and genomic alterations, eventually resulting in tumor burden accumulation and end-organ damage. It has been recently recognized that myeloma secondary genomic events result in extensive sub-clonal heterogeneity both in localized bone marrow areas and circulating peripheral blood plasma cells. Rare genomic subclones, including myeloma initiating cells, could be the drivers of disease progression and recurrence. Additionally, evaluation of rare myeloma cells in blood for disease monitoring has numerous advantages over invasive bone marrow biopsies. To this end, an unbiased method for detecting rare cells and delineating their genomic makeup enables disease detection and monitoring in conditions with low abundant cancer cells. In this study, we applied an enrichment-free four-plex (CD138, CD56, CD45, DAPI) immunofluorescence assay and single-cell DNA sequencing for morphogenomic characterization of plasma cells to detect and delineate common and rare plasma cells and discriminate between normal and malignant plasma cells in paired blood and bone marrow aspirates from five patients with newly diagnosed myeloma (N = 4) and monoclonal gammopathy of undetermined significance (n = 1). Morphological analysis confirms CD138+CD56+ cells in the peripheral blood carry genomic alterations that are clonally identical to those in the bone marrow. A subset of altered CD138+CD56- cells are also found in the peripheral blood consistent with the known variability in CD56 expression as a marker of plasma cell malignancy. Bone marrow tumor clinical cytogenetics is highly correlated with the single-cell copy number alterations of the liquid biopsy rare cells. A subset of rare cells harbors genetic alterations not detected by standard clinical diagnostic methods of random localized bone marrow biopsies. This enrichment-free morphogenomic approach detects and characterizes rare cell populations derived from the liquid biopsies that are consistent with clinical diagnosis and have the potential to extend our understanding of subclonality at the single-cell level in this disease. Assay validation in larger patient cohorts has the potential to offer liquid biopsy for disease monitoring with similar or improved disease detection as traditional blind bone marrow biopsies.

Tumor-associated macrophages in multiple myeloma: advances in biology and therapy

Multiple myeloma (MM) is a cancer of plasma cells in the bone marrow (BM) and represents the second most common hematological malignancy in the world. The MM tumor microenvironment (TME) within the BM niche consists of a wide range of elements which play important roles in supporting MM disease progression, survival, proliferation, angiogenesis, as well as drug resistance. Together, the TME fosters an immunosuppressive environment in which immune recognition and response are repressed. Macrophages are a central player in the immune system with diverse functions, and it has been long established that macrophages play a critical role in both inducing direct and indirect immune responses in cancer. Tumor-associated macrophages (TAMs) are a major population of cells in the tumor site. Rather than contributing to the immune response against tumor cells, TAMs in many cancers are found to exhibit protumor properties including supporting chemoresistance, tumor proliferation and survival, angiogenesis, immunosuppression, and metastasis. Targeting TAM represents a novel strategy for cancer immunotherapy, which has potential to indirectly stimulate cytotoxic T cell activation and recruitment, and synergize with checkpoint inhibitors and chemotherapies. In this review, we will provide an updated and comprehensive overview into the current knowledge on the roles of TAMs in MM, as well as the therapeutic targets that are being explored as macrophage-targeted immunotherapy, which may hold key to future therapeutics against MM.

A review on the treatment of multiple myeloma with small molecular agents in the past five years

Multiple myeloma is currently incurable, and the incidence rate is increasing year by year worldwide. Although in recent years the combined treatment plan based on proteasome inhibitors and immunomodulatory drugs has greatly improved the treatment effect of multiple myeloma, most patients still relapse and become resistant to current treatments. To solve this problem, scientists are committed to developing drugs with higher specificity, such as iberdomide, which is highly specific to ikaros and aiolos. This review aims to focus on the small molecular agents that are being researched/clinically used for the treatment of multiple myeloma, including the target mechanism, structure-activity relationship and application prospects of small molecular agents.

Alcohol and tobacco use and risk of multiple myeloma: A case-control study

Multiple myeloma (MM) is the second most common hematological cancer and causes significant mortality and morbidity. Knowledge regarding modifiable risk factors for MM remains limited. This analysis of an Australian population-based case-control family study investigates whether smoking or alcohol consumption is associated with risk of MM and related diseases. Incident cases (n = 789) of MM were recruited via cancer registries in Victoria and New South Wales. Controls (n = 1,113) were either family members of cases (n = 696) or controls recruited for a similarly designed study of renal cancers (n = 417). Adjusted odds ratios (OR) and 95% confidence intervals (CI) were estimated using unconditional multivariable logistic regression. Heavy intake (>20 g ethanol/day) of alcohol had a lower risk of MM compared with nondrinkers (OR = 0.68, 95% CI: 0.50-0.93), and there was an inverse dose-response relationship for average daily alcohol intake (OR per 10 g ethanol per day = 0.92, 95% CI: 0.86-0.99); there was no evidence of an interaction with sex. There was no evidence of an association with MM risk for smoking-related exposures (p > 0.18). The associations between smoking and alcohol with MM are similar to those with non-Hodgkin lymphoma. Further research into potential underlying mechanisms is warranted.

Discovery of novel and orally bioavailable CDK 4/6 inhibitors with high kinome selectivity, low toxicity and long-acting stability for the treatment of multiple myeloma

Multiple myeloma (MM) ranks second in malignant hematopoietic cancers, and the most common anti-MM drugs easily generate resistance. CDK4/6 have been validated to play determinant roles in MM, but no remarkable progress has been obtained from clinical trials of CDK4/6 inhibitors for MM. To discover novel CDK6 inhibitors with better potency and high druggability, structure-based virtual screening was conducted to identify compound 10. Further chemical optimization afforded a better derivative, compound 32, which exhibited strong inhibition of CDK4/6 and showed high selectivity over 360+ kinases, including homologous CDKs. The in vivo evaluation demonstrated that compound 32 possessed low toxicity (LD₅₀ > 10,000 mg/kg), favorable bioavailability (F% = 51%), high metabolic stability (t_1/2 > 24 h) and strong anti-MM potency. In summary, we discovered a novel CDK4/6 inhibitor bearing favorable drug-like properties and offered a great candidate for MM preclinical studies.

Comparison of Clinical Characteristics and Genetic Aberrations of Plasma Cell Disorders in Thailand Population

Multiple myeloma is an incurable malignancy of plasma cells resulting from impaired terminal B cell development. Almost all patients with multiple myeloma eventually have a relapse. Many studies have demonstrated the importance of the various genomic mutations that characterize multiple myeloma as a complex heterogeneous disease. In recent years, next-generation sequencing has been used to identify the genomic mutation landscape and clonal heterogeneity of multiple myeloma. This is the first study, a prospective observational study, to identify somatic mutations in plasma cell disorders in the Thai population using targeted next-generation sequencing. Twenty-seven patients with plasma cell disorders were enrolled comprising 17 cases of newly diagnosed multiple myeloma, 5 cases of relapsed/refractory multiple myeloma, and 5 cases of other plasma cell disorders. The pathogenic mutations were found in 17 of 27 patients. Seventy percent of those who had a mutation (12/17 patients) habored a single mutation, whereas the others had more than one mutation. Fifteen pathogenic mutation genes were identified: ATM, BRAF, CYLD, DIS3, DNMT3A, FBXW7, FLT3, GNA13, IRF4, KMT2A, NRAS, SAMHD1, TENT5C, TP53, and TRAF3. Most have previously been reported to be involved in the RAS/MAPK pathway, the nuclear factor kappa B pathway, the DNA-repair pathway, the CRBN pathway, tumor suppressor gene mutation, or an epigenetic mutation. However, the current study also identified mutations that had not been reported to be related to myeloma: GNA13 and FBXW7. Therefore, a deep understanding of molecular genomics would inevitably improve the clinical management of plasma cell disorder patients, and the increased knowledge would ultimately result in better outcomes for the patients.

Down-regulation of circ_0058058 suppresses proliferation, angiogenesis and metastasis in multiple myeloma through miR-338-3p/ATG14 pathway

Background

Multiple myeloma (MM) is one of the most frequently diagnosed hematological malignancy. Dysregulation of circular RNAs (circRNAs) has important impacts on MM process. Herein, this work aimed to investigate the role and mechanism of circ_0058058 in MM progression.

Methods

Levels of genes and proteins were detected by real-time reverse transcription PCR (RT-qPCR) and Western blot. CCK-8 assay, colony formation assay, EdU assay, flow cytometry, tube formation assay, transwell assay and Western blot were utilized to detect the proliferation, apoptosis, angiogenesis and metastasis of MM cells. The target relationship between miR-338-3p and circ_0058058 or ATG14 (autophagy related 14) was verified by dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. In vivo experiments were performed using Xenograft assay.

Results

Circ_0058058 was up-regulated in MM bone marrow aspirates and cells, knockdown of circ_0058058 reduced MM cell proliferation, angiogenesis and metastasis, but induced apoptosis in vitro. In a MM xenograft mouse model, circ_0058058 silencing reduced MM tumor growth and cell proliferation. Mechanistically, circ_0058058 acted as a sponge for miR-338-3p to up-regulate ATG14 expression, which was validated to be a target of miR-338-3p. Rescue assay showed that miR-338-3p inhibition reversed the antitumor effects of circ_0058058 knockdown on MM cell. Moreover, forced expression of miR-338-3p suppressed MM cell malignant phenotype, which was abolished by ATG14 up-regulation.

Conclusion

Circ_0058058 functions as a sponge for miR-338-3p to elevate ATG14 expression to promote MM cell proliferation, metastasis and angiogenesis, affording a potential therapeutic target for MM prevention.

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.

Biomimetic 3D Environment Based on Microgels as a Model for the Generation of Drug Resistance in Multiple Myeloma

The development of three-dimensional environments to mimic the in vivo cellular response is a problem in the building of disease models. This study aimed to synthesize and validate three-dimensional support for culturing monoclonal plasma cells (mPCs) as a disease model for multiple myeloma. The three-dimensional environment is a biomimetic microgel formed by alginate microspheres and produced on a microfluidic device whose surface has been functionalized by a layer-by-layer process with components of the bone marrow’s extracellular matrix, which will interact with mPC. As a proof of concept, RPMI 8226 cell line cells were cultured in our 3D culture platform. We proved that hyaluronic acid significantly increased cell proliferation and corroborated its role in inducing resistance to dexamethasone. Despite collagen type I having no effect on proliferation, it generated significant resistance to dexamethasone. Additionally, it was evidenced that both biomolecules were unable to induce resistance to bortezomib. These results validate the functionalized microgels as a 3D culture system that emulates the interaction between tumoral cells and the bone marrow extracellular matrix. This 3D environment could be a valuable culture system to test antitumoral drugs efficiency in multiple myeloma.

[Multiple myeloma from the pathologist's perspective]

BACKGROUND

Multiple myeloma (MM) is one of the most common hematological neoplasms and accounts for approximately 1% of human cancers.

OBJECTIVES

Description of current diagnostics and classification of MM and related plasma cell neoplasms from the pathology viewpoint.

MATERIALS AND METHODS

Current knowledge regarding pathology and genetics of MM is summarized and tissue-based diagnostics following international consensus classifications and the current S3 guideline are described.

RESULTS

MM and related neoplasms are composed of malignant plasma cells that secrete a monoclonal immunoglobulin, which is an important parameter of disease activity. MM shows a multistage development. Almost all cases are preceded by a clinically inapparent precursor lesion, monoclonal gammopathy of undetermined significance (MGUS), which can progress to smoldering myeloma with a higher tumor burden, but absence of organ damage. Systemic MM needs to be discerned from the localized forms, solitary osseous and primary extramedullary plasmacytoma. MM is genetically very heterogeneous and can be broadly subdivided into two cytogenetic groups, cases with primary IGH translocations and cases with hyperdiploidy. Intratumoral genetic heterogeneity is frequently pronounced and correlates with the size of focal lesions in imaging.

CONCLUSIONS

Diagnosis of plasma cell neoplasms is done according to the criteria of the International Myeloma Working Group (IWMG) and requires interdisciplinary evaluation of clinical, serological, pathological and radiological features. In addition to clinical parameters, molecular markers, especially cytogenetic aberrations, are of great prognostic relevance.

Pathogenesis and treatment of multiple myeloma bone disease

Multiple myeloma (Plasma cell myeloma), a malignancy of the plasma cells, exhibits tumor expansion preferentially in the bone marrow and the development of bone-destructive lesions. Multiple myeloma is still an incurable disease with changes in the bone marrow microenvironment in favor of the survival and proliferation of multiple myeloma cells and bone destruction. In this review, we described the recent findings on the regulators involved in the development of myeloma bone diseases, and succinctly summarize currently available therapeutic options and the development of novel bone modifying agents for myeloma treatment.

The Emerging Role of Extracellular Vesicle-Associated RNAs in the Multiple Myeloma Microenvironment

Multiple myeloma (MM) is a cancer of terminally differentiated plasma cells (PCs) that develop at multiple sites within the bone marrow (BM). MM is treatable but rarely curable because of the frequent emergence of drug resistance and relapse. Increasing evidence indicates that the BM microenvironment plays a major role in supporting MM-PC survival and resistance to therapy. The BM microenvironment is a complex milieu containing hematopoietic cells, stromal cells, endothelial cells, immune cells, osteoclasts and osteoblasts, all contributing to the pathobiology of MM, including PC proliferation, escape from immune surveillance, angiogenesis and bone disease development. Small extracellular vesicles (EVs) are heterogenous lipid structures released by all cell types and mediate local and distal cellular communication. In MM, EVs are key mediators of the cross-talk between PCs and the surrounding microenvironment because of their ability to deliver bioactive cargo molecules such as lipids, mRNAs, non-coding regulatory RNA and proteins. Hence, MM-EVs highly contribute to establish a tumor-supportive BM niche that impacts MM pathogenesis and disease progression. In this review, we will first highlight the effects of RNA-containing, MM-derived EVs on the several cellular compartments within the BM microenvironment that play a role in the different aspects of MM pathology. We will also touch on the prospective use of MM-EV-associated non-coding RNAs as clinical biomarkers in the context of “liquid biopsy” in light of their importance as a promising tool in MM diagnosis, prognosis and prediction of drug resistance.

Next generation proteomics with drug sensitivity screening identifies sub-clones informing therapeutic and drug development strategies for multiple myeloma patients

With the introduction of novel therapeutic agents, survival in Multiple Myeloma (MM) has increased in recent years. However, drug-resistant clones inevitably arise and lead to disease progression and death. The current International Myeloma Working Group response criteria are broad and make it difficult to clearly designate resistant and responsive patients thereby hampering proteo-genomic analysis for informative biomarkers for sensitivity. In this proof-of-concept study we addressed these challenges by combining an ex-vivo drug sensitivity testing platform with state-of-the-art proteomics analysis. 35 CD138-purified MM samples were taken from patients with newly diagnosed or relapsed MM and exposed to therapeutic agents from five therapeutic drug classes including Bortezomib, Quizinostat, Lenalidomide, Navitoclax and PF-04691502. Comparative proteomic analysis using liquid chromatography-mass spectrometry objectively determined the most and least sensitive patient groups. Using this approach several proteins of biological significance were identified in each drug class. In three of the five classes focal adhesion-related proteins predicted low sensitivity, suggesting that targeting this pathway could modulate cell adhesion mediated drug resistance. Using Receiver Operating Characteristic curve analysis, strong predictive power for the specificity and sensitivity of these potential biomarkers was identified. This approach has the potential to yield predictive theranostic protein panels that can inform therapeutic decision making.

Realization of Osteolysis, Angiogenesis, Immunosuppression, and Drug Resistance by Extracellular Vesicles: Roles of RNAs and Proteins in Their Cargoes and of Ectonucleotidases of the Immunosuppressive Adenosinergic Noncanonical Pathway in the Bone Marrow Niche of Multiple Myeloma

Simple Summary

Multiple myeloma (MM) is a disease that extensively involves bone, and angiogenesis and immunosuppression are important processes in the development of MM. Proteasome inhibitors and immunomodulatory drugs remarkably improve the survival of MM patients. However, MM is still an incurable disease that rapidly becomes resistant to these drugs. There is robust evidence that extracellular vesicles (EVs) contribute to cancer metastasis. Osteoclasts, in addition to immunosuppressive cells in the bone marrow (BM), are key players in osteolysis and immunosuppression. BM stromal cells and MM cells secrete EVs through which they communicate with each other: EVs, in fact, contain proteins, small RNAs, and long non-coding RNAs that mediate this communication and contribute to angiogenesis, osteolysis, and cancer dissemination and drug resistance. Ectoenzymes are expressed in myeloma cells, osteoclasts, and stromal cells and produce immunosuppressive adenosine. Recently, an antibody targeting CD38, an ectoenzyme, has been shown to improve the survival of patients with MM. Thus, understanding the properties of EV and ectoenzymes will help elucidate key processes of MM development.

Abstract

Angiogenesis and immunosuppression promote multiple myeloma (MM) development, and osteolysis is a primary feature of MM. Although immunomodulatory drugs and proteasome inhibitors (PIs) markedly improve the survival of patients with MM, this disease remains incurable. In the bone marrow niche, a chain of ectoenzymes, including CD38, produce immunosuppressive adenosine, inhibiting T cell proliferation as well as immunosuppressive cells. Therefore, anti-CD38 antibodies targeting myeloma cells have the potential to restore T cell responses to myeloma cells. Meanwhile extracellular vesicles (EVs) containing microRNAs, proteins such as cytokines and chemokines, long noncoding RNAs, and PIWI-interacting RNAs have been shown to act as communication tools in myeloma cell/microenvironment interactions. Via EVs, mesenchymal stem cells allow myeloma cell dissemination and confer PI resistance, whereas myeloma cells promote angiogenesis, myeloid-derived suppressor cell proliferation, and osteoclast differentiation and inhibit osteoblast differentiation. In this review, to understand key processes of MM development involving communication between myeloma cells and other cells in the tumor microenvironment, EV cargo and the non-canonical adenosinergic pathway are introduced, and ectoenzymes and EVs are discussed as potential druggable targets for the treatment of MM patients.

Iceland screens, treats, or prevents multiple myeloma (iStopMM): a population-based screening study for monoclonal gammopathy of undetermined significance and randomized controlled trial of follow-up strategies

Monoclonal gammopathy of undetermined significance (MGUS) precedes multiple myeloma (MM). Population-based screening for MGUS could identify candidates for early treatment in MM. Here we describe the Iceland Screens, Treats, or Prevents Multiple Myeloma study (iStopMM), the first population-based screening study for MGUS including a randomized trial of follow-up strategies. Icelandic residents born before 1976 were offered participation. Blood samples are collected alongside blood sampling in the Icelandic healthcare system. Participants with MGUS are randomized to three study arms. Arm 1 is not contacted, arm 2 follows current guidelines, and arm 3 follows a more intensive strategy. Participants who progress are offered early treatment. Samples are collected longitudinally from arms 2 and 3 for the study biobank. All participants repeatedly answer questionnaires on various exposures and outcomes including quality of life and psychiatric health. National registries on health are cross-linked to all participants. Of the 148,704 individuals in the target population, 80 759 (54.3%) provided informed consent for participation. With a very high participation rate, the data from the iStopMM study will answer important questions on MGUS, including potentials harms and benefits of screening. The study can lead to a paradigm shift in MM therapy towards screening and early therapy.

miR-15a/16-1 deletion in activated B cells promotes plasma cell and mature B-cell neoplasms

Chromosome 13q deletion [del(13q)], harboring the miR-15a/16-1 cluster, is one of the most common genetic alterations in mature B-cell malignancies, which originate from germinal center (GC) and post-GC B cells. Moreover, miR-15a/16 expression is frequently reduced in lymphoma and multiple myeloma (MM) cells without del(13q), suggesting important tumor-suppressor activity. However, the role of miR-15a/16-1 in B-cell activation and initiation of mature B-cell neoplasms remains to be determined. We show that conditional deletion of the miR-15a/16-1 cluster in murine GC B cells induces moderate but widespread molecular and functional changes including an increased number of GC B cells, percentage of dark zone B cells, and maturation into plasma cells. With time, this leads to development of mature B-cell neoplasms resembling human extramedullary plasmacytoma (EP) as well as follicular and diffuse large B-cell lymphomas. The indolent nature and lack of bone marrow involvement of EP in our murine model resembles human primary EP rather than MM that has progressed to extramedullary disease. We corroborate human primary EP having low levels of miR-15a/16 expression, with del(13q) being the most common genetic loss. Additionally, we show that, although the mutational profile of human EP is similar to MM, there are some exceptions such as the low frequency of hyperdiploidy in EP, which could account for different disease presentation. Taken together, our studies highlight the significant role of the miR-15a/16-1 cluster in the regulation of the GC reaction and its fundamental context-dependent tumor-suppression function in plasma cell and B-cell malignancies.

PI3 kinase signaling pathway in hematopoietic cancers: A glance in miRNA's role

Hematopoietic cancers are among the most common malignancies worldwide, which are divided into different types depending on the origin of tumor cells. In recent years, the pivotal role of different signaling pathways in the onset and progression of these cancer types has been well established. One of these pathways, whose role in blood malignancies has been well-defined, is PI3K/mTOR/AKT axis. The signaling pathway involves in a wide variety of important biological events in cells. It is clear that dysregulation of mediators involved in PI3 kinase signaling takes a pivotal role in cancer development. Considering the undeniable role of miRNAs, as one of the well-known families of non-coding RNAs, in gene regulation, we aimed to review the role of miRNAs in regulation of PI3 kinase signaling effectors in hematopoietic cancers.

Downregulation of ITGA6 confers to the invasion of multiple myeloma and promotes progression to plasma cell leukaemia

BACKGROUND

Secondary plasma cell leukaemia (sPCL) is an aggressive form of multiple myeloma (MM), but the mechanism underlying MM progresses into PCL remains unknown.

METHODS

Gene expression profiling of MM patients and PCL patients was analysed to identify the molecular differences between the two diseases. Cox survival regression and Kaplan-Meier analysis were performed to illustrate the impact of integrin subunit alpha 6 (ITGA6) on prognosis of MM. Invasion assays were performed to assess whether ITGA6 regulated the progression of MM to PCL.

RESULTS

Gene expression profiling analyses showed that cell metastasis pathways were enriched in PCL and ITGA6 was differentially expressed between PCL and MM. ITGA6 expression was an independent prognostic factor for event-free survival (EFS) and overall survival (OS) of MM patients. Moreover, the stratification ability of the International Staging System (ISS) of MM was improved when including ITGA6 expression. Functional studies uncovered that increased ITGA6 reduced the myeloma cell invasion. Additionally, low expression of ITGA6 resulted from epigenetic downregulating of its anti-sense non-coding RNA, ITGA6-AS1.

CONCLUSION

Our data reveal that ITGA6 gradually decreases during plasma cell dyscrasias progression and low expression of ITGA6 contributes to myeloma metastasis. Moreover, ITGA6 abundance might help develop MM prognostic stratification.

IDO2 rs10109853 polymorphism affects the susceptibility to multiple myeloma

Single-nucleotide polymorphisms (SNPs) of the IDO1 and IDO2 genes have been associated with some diseases. Here, we investigated the association of IDO1 and IDO2 SNPs with the susceptibility to multiple myeloma (MM) and their relationships with MM clinical features. We obtained genomic DNA from 100 patients with MM and 149 healthy race-matched controls and determined IDO1 promoter - 1849G/T (rs3824259) and IDO2 R248W (rs10109853) genotypes by using the polymerase chain reaction-restriction fragment length polymorphism method. The patients with MM had a significantly higher frequency of the IDO2 R248W RR genotype (high-activity type) (59.0% vs. 43.6%, odds ratio = 1.86, 95% confidence interval = 1.11-3.11, P = 0.017) compared with those in healthy controls. Patients with the IDO2 R248W RR genotype (high-activity type) were significantly younger and had a significantly lower frequency of International Staging System (ISS) stage III condition than those with the RW and WW genotypes (median 63 years vs. 69 years, P = 0.025; 15 [25.4%] vs. 50 [48.8%]). In addition, the IDO2 R248W RR genotype was significantly associated with a higher level of hemoglobin at diagnosis (mean ± standard deviation, 10.7 ± 2.36 vs. 9.27 ± 2.40 g/dL; P = 0.0032). Neither polymorphism significantly affected overall survival. Our study indicates that IDO2 R248W may be associated with the susceptibility to MM and severity of anemia.

Metabolic Effects of Recurrent Genetic Aberrations in Multiple Myeloma

Oncogene activation and malignant transformation exerts energetic, biosynthetic and redox demands on cancer cells due to increased proliferation, cell growth and tumor microenvironment adaptation. As such, altered metabolism is a hallmark of cancer, which is characterized by the reprogramming of multiple metabolic pathways. Multiple myeloma (MM) is a genetically heterogeneous disease that arises from terminally differentiated B cells. MM is characterized by reciprocal chromosomal translocations that often involve the immunoglobulin loci and a restricted set of partner loci, and complex chromosomal rearrangements that are associated with disease progression. Recurrent chromosomal aberrations in MM result in the aberrant expression of MYC, cyclin D1, FGFR3/MMSET and MAF/MAFB. In recent years, the intricate mechanisms that drive cancer cell metabolism and the many metabolic functions of the aforementioned MM-associated oncogenes have been investigated. Here, we discuss the metabolic consequences of recurrent chromosomal translocations in MM and provide a framework for the identification of metabolic changes that characterize MM cells.

The Role of Tumor Microenvironment in Multiple Myeloma Development and Progression

Simple Summary

Multiple Myeloma (MM) is a hematologic malignancy caused by aberrant plasma cell proliferation in the bone marrow (BM) and constitutes the second most common hematological disease after non-Hodgkin lymphoma. The disease progression is drastically regulated by the immunosuppressive tumor microenvironment (TME) generated by soluble factors and different cells that naturally reside in the BM. This microenvironment does not remain unchanged and alterations favor cancer dissemination. Despite therapeutic advances over the past 15 years, MM remains incurable and therefore understanding the elements that control the TME in MM would allow better-targeted therapies to cure this disease. In this review, we discuss the main events and changes that occur in the BM milieu during MM development.

Abstract

Multiple myeloma (MM) is a hematologic cancer characterized by clonal proliferation of plasma cells in the bone marrow (BM). The progression, from the early stages of the disease as monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM) to MM and occasionally extramedullary disease, is drastically affected by the tumor microenvironment (TME). Soluble factors and direct cell–cell interactions regulate MM plasma cell trafficking and homing to the BM niche. Mesenchymal stromal cells, osteoclasts, osteoblasts, myeloid and lymphoid cells present in the BM create a unique milieu that favors MM plasma cell immune evasion and promotes disease progression. Moreover, TME is implicated in malignant cell protection against anti-tumor therapy. This review describes the main cellular and non-cellular components located in the BM, which condition the immunosuppressive environment and lead the MM establishment and progression.

Targeting the Endothelin-1 Receptors Curtails Tumor Growth and Angiogenesis in Multiple Myeloma

The endothelin-1 (ET-1) receptors were recently found to mediate pro-survival functions in multiple myeloma (MM) cells in response to autocrine ET-1. This study investigated the effectiveness of macitentan, a dual ET-1 receptor antagonist, in MM treatment, and the mechanisms underlying its activities. Macitentan affected significantly MM cell (RPMI-8226, U266, KMS-12-PE) survival and pro-angiogenic cytokine release by down-modulating ET-1-activated MAPK/ERK and HIF-1α pathways, respectively. HIF-1α silencing abrogated the ET-1 mediated induction of genes encoding for pro-angiogenic cytokines such as VEGF-A, IL-8, Adrenomedullin, and ET-1 itself. Upon exposure to macitentan, MM cells cultured in the presence of the hypoxia-mimetic agent CoCl₂, exogenous ET-1, or CoCl₂ plus ET-1, down-regulated HIF-1α and the transcription and release of downstream pro-angiogenic cytokines. Consistently, macitentan limited significantly the basal pro-angiogenic activity of RPMI-8226 cells in chorioallantoic membrane assay. In xenograft mouse models, established by injecting NOG mice either via intra-caudal vein with U266 or subcutaneously with RPMI-8226 cells, macitentan reduced effectively the number of MM cells infiltrating bone marrow, and the size and microvascular density of subcutaneous MM tumors. ET-1 receptors targeting by macitentan represents an effective anti-proliferative and anti-angiogenic therapeutic approach in preclinical settings of MM.

Adherence to and effectiveness of lenalidomide after 1 year of treatment in a real world setting

BACKGROUND

In combination with dexamethasone, lenalidomide is prescribed in the oral treatment of Multiple Myeloma for patients who have received at least one previous therapy.

OBJECTIVE

The objective of this study is to evaluate medication adherence to lenalidomide of Multiple Myeloma patients, as well as Progression Free Survival and Overall Survival one year from the beginning of the treatment.

SETTING

The study was carried out in Pescara Hospital, in Italy. All Multiple Myeloma patients who began lenalidomide therapy between January 1, 2012 and June 30, 2016 were included in our study.

METHODS

Adherence to treatment was calculated by using the ratio between the Received Daily Dose and the Prescribed Daily Dose. Effectiveness in real world has been evaluated as Progression Free Survival and Overall Survival one year from the beginning of the treatment.Main outcomes measure: We assessed medication adherence and effectiveness of lenalidomide in the treatment of Multiple Myeloma.

RESULTS

Adherence to the overall mean treatment was 0.73 ± 0.15, relative to 81 patients evaluated in our study. 32% of patients achieved an adherence equal to or greater than 80%. Real-life effectiveness in terms of Progression Free Survival and Overall Survival showed values of ​​53.75% and 88%, respectively, one year from the beginning of treatment.

CONCLUSION

The analysis of adherence in Multiple Myeloma patients treated with lenalidomide one year from the beginning of therapy reveal a concerning lack of adherence. Moreover, the lack of correlation of the levels of adherence with patient-related variables shows that, in the case of Multiple Myeloma, adherence is not related to personal, social and environmental characteristics that may determine each patient's correct treatment implementation, but is directly influenced by disease evolution.

Changing paradigms in diagnosis and treatment of monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM)

Multiple myeloma (MM) is a highly heterogenous disease that exists along a continuous disease spectrum starting with premalignant conditions monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM) that inevitably precede MM. Over the past two decades, significant progress has been made in the genetic characterization and risk stratification of precursor plasma cell disorders. Indeed, the clinical introduction of highly effective and well-tolerated drugs begs the question: would earlier therapeutic intervention with novel therapies in MGUS and SMM patients alter natural history, providing a potential curative option? In this review, we discuss the epidemiology of MGUS and SMM and current models for risk stratification that predict MGUS and SMM progression to MM. We further discuss genetic heterogeneity and clonal evolution in MM and the interplay between tumor cells and the bone marrow (BM) microenvironment. Finally, we provide an overview of the current recommendations for the management of MGUS and SMM and discuss the open controversies in the field in light of promising results from early intervention clinical trials.

Epigenetic silencing of long non-coding RNA BM742401 in multiple myeloma: impact on prognosis and myeloma dissemination

Background

Long non-coding RNA (lncRNA) BM742401 is a tumor suppressor in gastric cancer and chronic lymphocytic leukemia. As the promoter and coding region of BM742401 are fully embedded in a CpG island, we hypothesized that BM742401 is a tumor suppressor lncRNA epigenetically silenced by promoter DNA methylation in multiple myeloma.

Methods

Methylation-specific PCR and quantitative bisulfite pyrosequencing were performed to detect the methylation of BM742401 in normal plasma cells, myeloma cell lines and primary myeloma samples. The expression of BM742401 was measured by qRT-PCR. The function of BM742401 in multiple myeloma cells was analyzed by lentivirus transduction followed by migration assay.

Results

BM742401 methylation was detected in 10 (66.7%) myeloma cell lines but not normal plasma cells, and inversely correlated with expression of BM742401. In primary samples, BM742401 methylation was detected in 3 (12.5%) monoclonal gammopathy of undetermined significance, 9 (15.8%) myeloma at diagnosis and 8 (17.0%) myeloma at relapse/progression. Moreover, BM742401 methylation at diagnosis was associated with inferior overall survival (median OS: 25 vs. 39 months; P = 0.0496). In myeloma cell line JJN-3, stable overexpression of BM742401 by lentivirus transduction resulted in reduced cell migration (P = 0.0001) but not impacting cell death or proliferation.

Conclusions

This is the first report of tumor-specific methylation-mediated silencing of BM742401 in myeloma, which is likely an early event in myelomagenesis with adverse impact on overall survival. Moreover, BM742401 is a tumor suppressor lncRNA by inhibiting myeloma cell migration, hence implicated in myeloma plasma cell homing, metastasis and disease progression.

NY-ESO-1 Protein Vaccine Combining Alum, CpG ODN, and HH2 Complex Adjuvant Induces Protective and Therapeutic Anti-Tumor Responses in Murine Multiple Myeloma

Background

NY-ESO-1 is an ideal target for multiple myeloma immunotherapy. Alum, CpG ODN and HH2 complex is a safe and effective adjuvant for cancer vaccine.

Methods

We constructed NY-ESO-1 protein vaccine combined with alum, CpG ODN, and HH2 complex adjuvant to immunize the BALB/c mice inoculated with NS-1 murine multiple myeloma cells. Then, we determined the immunogenicity and anti-tumor effects in prophylactic and therapeutic models by analyzing the NY-ESO-1 antibody titer, evaluating IL4/INF-γ expression, and assessing cytotoxic T lymphocytes activities. The side-effects of vaccines were also evaluated.

Results

The group of NY-ESO-1 protein vaccine combining alum, CpG ODN, and HH2 complex adjuvant is more capable of stimulating both humoral and cellular tumor-specific immune responses to prolong the survival of the mice and inhibit tumor growth in prophylactic and therapeutic immunotherapy. The marked side-effects were not detected in immunized mice.

Discussion

The results suggest that alum, CpG ODN, and HH2 complex as a novel immune adjuvant combined cancer vaccine could improve the immunity efficiency in a murine multiple myeloma model.

Role of the Bone Marrow Milieu in Multiple Myeloma Progression and Therapeutic Resistance

Multiple myeloma (MM) is a cancer of the plasma cells within the bone marrow (BM). Studies have shown that the cellular and noncellular components of the BM milieu, such as cytokines and exosomes, play an integral role in MM pathogenesis and progression by mediating drug resistance and inducing MM proliferation. Moreover, the BM microenvironment of patients with MM facilitates cancer tolerance and immune evasion through the expansion of regulatory immune cells, inhibition of antitumor effector cells, and disruption of the antigen presentation machinery. These are of special relevance, especially in the current era of cancer immunotherapy. An improved understanding of the supportive role of the MM BM microenvironment will allow for the development of future therapies targeting MM in the context of the BM milieu to elicit deeper and more durable responses. In the present review, we have discussed our current understanding of the role of the BM microenvironment in MM progression and resistance to therapy and discuss novel potential approaches to alter its pro-MM function.

IGF-1 promotes multiple myeloma progression through PI3K/Akt-mediated epithelial-mesenchymal transition

AIMS

To investigate the role and mechanism of insulin-like growth factor 1(IGF-1)-mediated EMT on multiple myeloma (MM) growth and metastasis.

MATERIALS AND METHODS

The expression data from GEO datasets were utilized to explore the expression levels of IGF-1 and epithelial-mesenchymal transition (EMT) markers in MM. Western blotting and flow cytometry analysis were performed to detect the protein levels of EMT markers as well as key components of the PI3K/Akt pathway. Cell proliferation ability was assessed using colony formation assay and EdU incorporation assays. Transwell migration and invasion assays were performed to assess cell metastasis properties. Vimentin was knocked down by using electro-transfection with small interfering RNA (siRNA) to detect the effect of IGF-1-mediated EMT on MM cell growth and metastasis.

KEY FINDINGS

First of all, the analysis of GEO database revealed that IGF-1 was excessively expressed and closely correlated with the expression of the EMT markers in MM patients. Furthermore, we demonstrated that IGF-1 enhanced the acquisition of mesenchymal features in a time-dependent manner. Additionally, in vitro studies revealed that IGF-1-mediated mesenchymal phenotype promoted MM migration, invasion and colony formation. Finally, the mechanism study showed PI3K/Akt signaling pathway was involved in the IGF-1-induced EMT in MM cells.

SIGNIFICANCE

IGF-1-induced mesenchymal phenotype contributed to MM progression via the PI3K/Akt pathway regulation.

MicroRNAs-Based Nano-Strategies as New Therapeutic Approach in Multiple Myeloma to Overcome Disease Progression and Drug Resistance

MicroRNAs (miRNAs, or miRs) are single-strand short non-coding RNAs with a pivotal role in the regulation of physiological- or disease-associated cellular processes. They bind to target miRs modulating gene expression at post-transcriptional levels. Here, we present an overview of miRs deregulation in the pathogenesis of multiple myeloma (MM), and discuss the potential use of miRs/nanocarriers association in clinic. Since miRs can act as oncogenes or tumor suppressors, strategies based on their inhibition and/or replacement represent the new opportunities in cancer therapy. The miRs delivery systems include liposomes, polymers, and exosomes that increase their physical stability and prevent nuclease degradation. Phase I/II clinical trials support the importance of miRs as an innovative therapeutic approach in nanomedicine to prevent cancer progression and drug resistance. Results in clinical practice are promising.

Runx2 Deficiency in Osteoblasts Promotes Myeloma Progression by Altering the Bone Microenvironment at New Bone Sites

Multiple myeloma is a plasma cell malignancy that thrives in the bone marrow (BM), with frequent progression to new local and distant bone sites. Our previous studies demonstrated that multiple myeloma cells at primary sites secrete soluble factors and suppress osteoblastogenesis via the inhibition of Runt-related transcription factor 2 (Runx2) in pre- and immature osteoblasts (OB) in new bone sites, prior to the arrival of metastatic tumor cells. However, it is unknown whether OB-Runx2 suppression in new bone sites feeds back to promote multiple myeloma dissemination to and progression in these areas. Hence, we developed a syngeneic mouse model of multiple myeloma in which Runx2 is specifically deleted in the immature OBs of C57BL6/KaLwRij mice (OB-Runx2-/- mice) to study the effect of OB-Runx2 deficiency on multiple myeloma progression in new bone sites. In vivo studies with this model demonstrated that OB-Runx2 deficiency attracts multiple myeloma cells and promotes multiple myeloma tumor growth in bone. Mechanistic studies further revealed that OB-Runx2 deficiency induces an immunosuppressive microenvironment in BM that is marked by an increase in the concentration and activation of myeloid-derived suppressor cells (MDSC) and the suppression and exhaustion of cytotoxic CD8+ T cells. In contrast, MDSC depletion by either gemcitabine or 5-fluorouracil treatment in OB-Runx2-/- mice prevented these effects and inhibited multiple myeloma tumor growth in BM. These novel discoveries demonstrate that OB-Runx2 deficiency in new bone sites promotes multiple myeloma dissemination and progression by increasing metastatic cytokines and MDSCs in BM and inhibiting BM immunity. Importantly, MDSC depletion can block multiple myeloma progression promoted by OB-Runx2 deficiency.Significance: This study demonstrates that Runx2 deficiency in immature osteoblasts at distant bone sites attracts myeloma cells and allows myeloma progression in new bone sites via OB-secreted metastatic cytokines and MDSC-mediated suppression of bone marrow immunity.

Multiple Myeloma: Available Therapies and Causes of Drug Resistance

Multiple myeloma (MM) is the second most common blood cancer. Treatments for MM include corticosteroids, alkylating agents, anthracyclines, proteasome inhibitors, immunomodulatory drugs, histone deacetylase inhibitors and monoclonal antibodies. Survival outcomes have improved substantially due to the introduction of many of these drugs allied with their rational use. Nonetheless, MM patients successively relapse after one or more treatment regimens or become refractory, mostly due to drug resistance. This review focuses on the main drugs used in MM treatment and on causes of drug resistance, including cytogenetic, genetic and epigenetic alterations, abnormal drug transport and metabolism, dysregulation of apoptosis, autophagy activation and other intracellular signaling pathways, the presence of cancer stem cells, and the tumor microenvironment. Furthermore, we highlight the areas that need to be further clarified in an attempt to identify novel therapeutic targets to counteract drug resistance in MM patients.

PDCD1 and PDCD1LG1 polymorphisms affect the susceptibility to multiple myeloma

Single-nucleotide polymorphisms (SNPs) of the programmed cell death protein-1 (PDCD1), programmed cell death protein-1 ligand-1 (PDCD1LG1), and cytotoxic T lymphocyte-associated antigen-4 (CTLA4) genes are implicated in the pathogenesis of some cancers. We investigated the role of PDCD1, PDCD1LG1, and CTLA4 SNPs in MM pathogenesis and the susceptibility to and clinical features of multiple myeloma (MM). We obtained genomic DNA from 124 patients with MM and 211 healthy controls and detected PDCD1 (rs36084323, rs41386349, and rs2227982), PDCD1LG1 (rs2297136 and rs4143815), and CTLA4 (rs733618, rs11571316, rs231775, and rs3087243) genotypes using the polymerase chain reaction-restriction fragment length polymorphism method or the TaqMan allelic discrimination real-time PCR method. The patients with MM had a significantly higher frequency of the PDCD1 GCC/GCC haplotype (rs36084323/rs41386349/rs2227982) compared with the healthy controls. PDCD1 rs2227982 CC genotype was associated significantly with a higher frequency of bone lesions. Patients with PDCD1LG1 rs2297136 TT and TC types (high-expression types) showed lower albumin level than those with CC genotype. In addition, the PDCD1LG1 rs4143815 CC and CG types (high-expression types) were associated significantly with higher frequency of patients who were treated with thalidomide and/or bortezomib. However, there was no statistical significance between CTLA4 polymorphisms and clinical variables of patients with MM. There were no significant differences between all the polymorphisms and OS. Our study indicates that the PDCD1 haplotype is associated with a susceptibility to MM. The PDCD1 rs2227982 and PDCD1LG1 rs2297136 affect the clinical features of multiple myeloma patients.