Understanding multiple myeloma pathogenesis in the bone marrow to identify new therapeutic targets

lncRNA H19 plays a role in multiple myeloma via interacting with hnRNPA2B1 to stabilize BET proteins by targeting osteoclasts and osteoblasts

BACKGROUND

Multiple myeloma (MM), characterized with bone marrow microenvironment disorder, accounts for about 20% of hematological cancer deaths globally. Tissue extracellular communication, especially extracellular vesicles, has been defined as important mediator among cell-to-cell cross-talk. Our previous study revealed an elevated level of H19 in MM, whereas, its role in MM exosomes in the development of osteolysis remains largely unknown.

METHOD

MM exosomes referring to 5TGM1 cells were isolated and characterized using transmission electron microscopy (TEM), nanoparticle tracking and western blot analysis. The biological effects of blocking H19 were examined on osteolysis in vivo of C57Bl6/KalwRij mice, as well as on the osteoclast differentiation in vitro of RAW264.7 cells, by the application of TRAP, either with osteogenic differentiation in vitro of bone marrow mesenchymal stem cells (BMSCs), by the detection of alkaline phosphatase (ALP), alizarin red dye staining (ARS). The targeted relationships among H19/hnRNPA2B1/BET proteins were validated through RNA immunoprecipitation (RIP) and RNA pull-down assays.

RESULTS

5TGM1 cells derived-exosomes lacking H19 dramatically blocked osteolysis and boosted osteogeneis in C57Bl6/KalwRij mice, either with osteoclastic differentiation of RAW264.7 cells and osteogenic differentiation of BMSCs, thereby enhancing their resorptive activity. Physically, H19 interacted with hnRNPA2B1 by preferentially adhering to it and enhancing its nuclear-cytoplasmic translocation. Further mechanistic research validated that H19 promoted the stabilization of BET proteins through hnRNA2B1 to be involved in osteoclast differentiation for contributing to MM progression.

CONCLUSION

Altogether, our findings suggest that H19, serving as an essential role for exosomes in the bone marrow environment, might be a viable diagnostic and therapeutic target for MM therapy.

Management of bone disease with concurrent chimeric antigen receptor T-cell therapy for multiple myeloma

In the intricate landscape of multiple myeloma, a hematologic malignancy of plasma cells, bone disease presents a pivotal and often debilitating complication. The emergence of Chimeric Antigen Receptor T-cell (CAR-T) therapy has marked a pivotal shift in the therapeutic landscape, offering novel avenues for the management of MM, particularly for those with relapsed or refractory disease. This innovative treatment modality not only targets malignant cells with precision but also influences the bone microenvironment, presenting both challenges and opportunities in patient care. In this comprehensive review, we aim to examine the multifaceted aspects of bone disease in patients with multiple myeloma and concurrent CAR-T therapy, highlighting its clinical ramifications and the latest advancements in diagnostic modalities and therapeutic interventions. The article aims to synthesize current understanding of the interplay between myeloma cells, CAR-T cells, and the bone microenvironment in the context of current treatment strategies in this challenging and unique patient population.

The TGFβ type I receptor kinase inhibitor vactosertib in combination with pomalidomide in relapsed/refractory multiple myeloma: a phase 1b trial

Functional blockade of the transforming growth factor-beta (TGFβ) signalling pathway improves the efficacy of cytotoxic and immunotherapies. Here, we conducted a phase 1b study (ClinicalTrials.gov., NCT03143985) to determine the primary endpoints of safety, tolerability, and maximal tolerated dose (200 mg twice daily) for the orally-available TGFβ type I receptor kinase inhibitor vactosertib in combination with pomalidomide in relapsed and/or refractory multiple myeloma (RRMM) patients who had received ≥2 lines of chemoimmunotherapy. Secondary endpoints demonstrated sustained clinical responses, favorable pharmacokinetic parameters and a 6-month progression-free survival of 82%. Vactosertib combined with pomalidomide was well-tolerated at all dose levels and displayed a manageable adverse event profile. Exploratory analysis indicated that vactosertib co-treatment with pomalidomide also reduced TGFβ levels in patient bone marrow as well as the level of CD8+ T-cells that expressed the immunoinhibitory marker PD-1. In vitro experiments indicated that vactosertib+pomalidomide co-treatment decreased the viability of MM cell lines and patient tumor cells, and increased CD8+ T-cell cytotoxic activity. Vactosertib is a safe therapeutic that demonstrates tumor-intrinsic activity and can overcome immunosuppressive challenges within the tumor microenvironment to reinvigorate T-cell fitness. Vactosertib offers promise to improve immunotherapeutic responses in heavily-pretreated MM patients refractory to conventional agents.

AP-1 inhibitor induces ferroptosis via the PI3K/AKT pathway in multiple myeloma cells

Multiple myeloma (MM) is an incurable malignancy of plasma cells that is sensitive to T-5224, an AP-1 inhibitor. Previous study indicated that T-5224 inhibits proliferation and induces apoptosis in MM cells. However, the high mortality cannot be fully explained. To date, no studies have investigated ferroptosis induced by T-5224 in MM. Therefore, we further investigated the mechanism by which T-5224 kills MM cells. We observed that T-5224 exhibits antimyeloma properties both in vitro and in vivo. T-5224-induced MM cell death was reversed by the ferroptosis-specific inhibitor ferropstatin-1 (Fer-1). The protein levels of the key ferroptosis regulators GPX4 and SLC7A11 were decreased by T-5224 in MM cells. Furthermore, T-5224 reduced the phosphorylation of PI3K and AKT signaling pathway components, ultimately causing MM cell death. Using 740 Y-P, a PI3K activator, and Fer-1, a ferroptosis inhibitor, we discovered that T-5224 induces ferroptosis through the PI3K/AKT pathway. Bortezomib (BTZ), an FDA-approved drug for MM treatment, can be administered in combination with other agents. We evaluated the synergistic effect of BTZ combined with AP-1 inhibitors on MM in vivo. Our findings provide a better theoretical basis for the potential mechanism of T-5224 and a new perspective on MM treatment.

Pro-survival signaling regulates lipophagy essential for multiple myeloma resistance to stress-induced death

Pro-survival metabolic adaptations to stress in tumorigenesis remain less well defined. We find that multiple myeloma (MM) is unexpectedly dependent on beta-oxidation of long-chain fatty acids (FAs) for survival under both basal and stress conditions. However, under stress conditions, a second pro-survival signal is required to sustain FA oxidation (FAO). We previously found that CD28 is expressed on MM cells and transduces a significant pro-survival/chemotherapy resistance signal. We now find that CD28 signaling regulates autophagy/lipophagy that involves activation of the Ca2+→AMPK→ULK1 axis and regulates the translation of ATG5 through HuR, resulting in sustained lipophagy, increased FAO, and enhanced MM survival. Conversely, blocking autophagy/lipophagy sensitizes MM to chemotherapy in vivo. Our findings link a pro-survival signal to FA availability needed to sustain the FAO required for cancer cell survival under stress conditions and identify lipophagy as a therapeutic target to overcome treatment resistance in MM.

Advancements in microenvironment-based therapies: transforming the landscape of multiple myeloma treatment

Multiple myeloma (MM) is the most prevalent malignant monoclonal disease of plasma cells. There is mounting evidence that interactions with the bone marrow (BM) niche are essential for the differentiation, proliferation, survival, migration, and treatment resistance of myeloma cells. For this reason, gaining a deeper comprehension of how BM microenvironment compartments interact with myeloma cells may inspire new therapeutic ideas that enhance patient outcomes. This review will concentrate on the most recent findings regarding the mechanisms of interaction between microenvironment and MM and highlight research on treatment targeting the BM niche.

Transcriptome of bone marrow-Derived stem cells reveals new inflammatory mediators related to increased survival in patients with multiple myeloma

Although multiple myeloma (MM) is a neoplasm that leads affected individuals to death, little is known about why some patients survive much longer than others. In this context, we investigated the transcriptomic profile of bone marrow hematopoietic stem cells obtained from MM patients and compared the clinical outcomes of death and survival six months after bone marrow transplantation. The leukapheresis products of 39 patients with MM eligible for autologous transplantation were collected and analyzed. After extraction, the RNA was analyzed using the GeneChip Human Exon 1.0 Array method. The transcriptome profile was analyzed in silico, and the differentially expressed signaling pathways of interest were validated. The results showed a difference in the expression of inflammation-related genes, immune response processes, and the oxidative stress pathway. The in silico study also pointed out the involvement of the NFκB transcription factor in the possible modulation of these genes. We chose to validate molecules participating in these processes, including the cytokines TNF-α, IFN-γ, and TGF-β1; in addition, we measured the levels of oxidative stress mediators (pro-oxidant profile and the total antioxidant capacity). TNF-α levels were significantly reduced in patients who died and were over 50 years old at diagnosis, as well as in patients with plasmacytoma. Increased TNF-α was detected in patients with very high levels of β2-microglobulin. IFN-γ reduction was observed in patients with a complete response to treatment compared to those with a very good response. Patients with plasmacytoma who died also had an increased pro-oxidant profile. These data show the profile of inflammatory response markers that are altered in patients with MM who die quickly and serve as a basis for the development of future studies of markers to predict better survival in this disease.

Pathways to therapy resistance: The sheltering effect of the bone marrow microenvironment to multiple myeloma cells

Multiple Myeloma (MM) is a malignant expansion of plasma cells in the bone marrow (BM), resulting in a disease characterized by symptoms of end organ damage from light chain secretion, crowding of the BM, and bone lesions. Although the past two decades have been characterized by numerous novel therapies emerging, the disease remains incurable due to intrinsic or acquired drug resistance. A major player in MM's drug resistance arises from its intimate relationship with the BM microenvironment (BMME). Through stress-inducing conditions, soluble messengers, and physical adhesion to BM elements, the BMME activates numerous pathways in the myeloma cell. This not only propagates myeloma progression through survival and growth signals, but also specific mechanisms to circumvent therapeutic actions. In this review, we provide an overview of the BMME, the role of individual components in MM survival, and various therapy-specific resistance mechanisms reported in the literature.

Multiple myeloma

Multiple myeloma (MM) is a haematological lymphoid malignancy involving tumoural plasma cells and is usually characterized by the presence of a monoclonal immunoglobulin protein. MM is the second most common haematological malignancy, with an increasing global incidence. It remains incurable because most patients relapse or become refractory to treatments. MM is a genetically complex disease with high heterogeneity that develops as a multistep process, involving acquisition of genetic alterations in the tumour cells and changes in the bone marrow microenvironment. Symptomatic MM is diagnosed using the International Myeloma Working Group criteria as a bone marrow infiltration of ≥10% clonal plasma cells, and the presence of at least one myeloma-defining event, either standard CRAB features (hypercalcaemia, renal failure, anaemia and/or lytic bone lesions) or biomarkers of imminent organ damage. Younger and fit patients are considered eligible for transplant. They receive an induction, followed by consolidation with high-dose melphalan and autologous haematopoietic cell transplantation, and maintenance therapy. In older adults (ineligible for transplant), the combination of daratumumab, lenalidomide and dexamethasone is the preferred option. If relapse occurs and requires further therapy, the choice of therapy will be based on previous treatment and response and now includes immunotherapies, such as bi-specific monoclonal antibodies and chimeric antigen receptor T cell therapy.

Research strategies of small molecules as chemotherapeutics to overcome multiple myeloma resistance

Multiple myeloma (MM), a cancer of plasma cells, is the second most common hematological malignancy which is characterized by aberrant plasma cells infiltration in the bone marrow and complex heterogeneous cytogenetic abnormalities. Over the past two decades, novel treatment strategies such as proteasome inhibitors, immunomodulators, and monoclonal antibodies have significantly improved the relative survival rate of MM patients. However, the development of drug resistance results in the majority of MM patients suffering from relapse, limited treatment options and uncontrolled disease progression after relapse. There are urgent needs to develop and explore novel MM treatment strategies to overcome drug resistance and improve efficacy. Here, we review the recent small molecule therapeutic strategies for MM, and introduce potential new targets and corresponding modulators in detail. In addition, this paper also summarizes the progress of multi-target inhibitor therapy and protein degradation technology in the treatment of MM.

Small RNA-seq and clinical evaluation of tRNA-derived fragments in multiple myeloma: Loss of mitochondrial i-tRFHisGTG results in patients' poor treatment outcome

Despite the substantial progress in multiple myeloma (MM) therapy nowadays, treatment resistance and disease relapse remain major clinical hindrances. Herein, we have investigated tRNA-derived fragment (tRF) profiles in MM and precursor stages (smoldering MM/sMM; monoclonal gammopathy of undetermined significance/MGUS), aiming to unveil potential MM-related tRFs in ameliorating MM prognosis and risk stratification. Small RNA-seq was performed to profile tRFs in bone marrow CD138+ plasma cells, revealing the significant deregulation of the mitochondrial internal tRFHisGTG (mt-i-tRFHisGTG) in MM versus sMM/MGUS. The screening cohort of the study consisted of 147 MM patients, and mt-i-tRFHisGTG levels were quantified by RT-qPCR. Disease progression was assessed as clinical end-point for survival analysis, while internal validation was performed by bootstrap and decision curve analyses. Screening cohort analysis highlighted the potent association of reduced mt-i-tRFHisGTG levels with patients' bone disease (p = 0.010), osteolysis (p = 0.023) and with significantly higher risk for short-term disease progression following first-line chemotherapy, independently of patients' clinical data (HR = 1.954; p = 0.036). Additionally, mt-i-tRFHisGTG-fitted multivariate models led to superior risk stratification of MM patients' treatment outcome and prognosis compared to disease-established markers. Notably, our study highlighted mt-i-tRFHisGTG loss as a powerful independent indicator of post-treatment progression of MM patients, leading to superior risk stratification of patients' treatment outcome.

Modeling Myeloma Dissemination In Vitro with hMSC-interacting Subpopulations of INA-6 Cells and Their Aggregation/Detachment Dynamics

Multiple myeloma involves early dissemination of malignant plasma cells across the bone marrow; however, the initial steps of dissemination remain unclear. Human bone marrow-derived mesenchymal stromal cells (hMSC) stimulate myeloma cell expansion (e.g., IL6) and simultaneously retain myeloma cells via chemokines (e.g., CXCL12) and adhesion factors. Hence, we hypothesized that the imbalance between cell division and retention drives dissemination. We present an in vitro model using primary hMSCs cocultured with INA-6 myeloma cells. Time-lapse microscopy revealed proliferation and attachment/detachment dynamics. Separation techniques (V-well adhesion assay and well plate sandwich centrifugation) were established to isolate MSC-interacting myeloma subpopulations that were characterized by RNA sequencing, cell viability, and apoptosis. Results were correlated with gene expression data (n = 837) and survival of patients with myeloma (n = 536). On dispersed hMSCs, INA-6 saturate hMSC surface before proliferating into large homotypic aggregates, from which single cells detached completely. On confluent hMSCs, aggregates were replaced by strong heterotypic hMSC-INA-6 interactions, which modulated apoptosis time dependently. Only INA-6 daughter cells (nMA-INA6) detached from hMSCs by cell division but sustained adherence to hMSC-adhering mother cells (MA-INA6). Isolated nMA-INA6 indicated hMSC autonomy through superior viability after IL6 withdrawal and upregulation of proliferation-related genes. MA-INA6 upregulated adhesion and retention factors (CXCL12), that, intriguingly, were highly expressed in myeloma samples from patients with longer overall and progression-free survival, but their expression decreased in relapsed myeloma samples. Altogether, in vitro dissemination of INA-6 is driven by detaching daughter cells after a cycle of hMSC-(re)attachment and proliferation, involving adhesion factors that represent a bone marrow-retentive phenotype with potential clinical relevance.

SIGNIFICANCE

Novel methods describe in vitro dissemination of myeloma cells as detachment of daughter cells after cell division. Myeloma adhesion genes were identified that counteract in vitro detachment with potential clinical relevance.

MYC dependency in GLS1 and NAMPT is a therapeutic vulnerability in multiple myeloma

Multiple myeloma (MM) is an incurable hematological malignancy in which MYC alterations contribute to the malignant phenotype. Nevertheless, MYC lacks therapeutic druggability. Here, we leveraged large-scale loss-of-function screens and conducted a small molecule screen to identify genes and pathways with enhanced essentiality correlated with MYC expression. We reported a specific gene dependency in glutaminase (GLS1), essential for the viability and proliferation of MYC overexpressing cells. Conversely, the analysis of isogenic models, as well as cell lines dataset (CCLE) and patient datasets, revealed GLS1 as a non-oncogenic dependency in MYC-driven cells. We functionally delineated the differential modulation of glutamine to maintain mitochondrial function and cellular biosynthesis in MYC overexpressing cells. Furthermore, we observed that pharmaceutical inhibition of NAMPT selectively affects MYC upregulated cells. We demonstrate the effectiveness of combining GLS1 and NAMPT inhibitors, suggesting that targeting glutaminolysis and NAD synthesis may be a promising strategy to target MYC-driven MM.

Impact of Clonal Heterogeneity in Multiple Myeloma

Multiple myeloma is characterized by a highly heterogeneous disease distribution within the bone marrow-containing skeletal system. In this review, we introduce the molecular mechanisms underlying clonal heterogeneity and the spatio-temporal evolution of myeloma. We discuss the clinical impact of clonal heterogeneity, which is thought to be one of the biggest obstacles to overcome therapy resistance and to achieve cure.

Immunocompetent Mouse Models of Multiple Myeloma: Therapeutic Implications

Immunocompetent mouse models of multiple myeloma (MM) are particularly needed in the era of T cell redirected therapy to understand drivers of sensitivity and resistance, optimize responses, and prevent toxicities. Three mouse models have been extensively characterized: the Balb/c plasmacytomas, the 5TMM, and the Vk*MYC. In the last year, additional models have been generated, which, for the first time, capture primary MM initiating events, like MMSET/NSD2 or cyclin D1 dysregulation. However, the long latency needed for tumor development and the lack of transplantable lines limit their utilization. Future studies should focus on modeling hyperdiploid MM.

Quantification of cyclin D1 and D2 proteins in multiple myeloma identifies different expression patterns from those revealed by gene expression profiling

Upregulation of a cyclin D gene determined by expression microarrays is an almost universal event in multiple myeloma (MM), but this finding has not been properly confirmed at the protein level. For this reason, we carried out a quantitative analysis of cyclin D proteins using a capillary electrophoresis nanoimmunoassay in newly diagnosed MM patients. Exclusive expression of cyclin D1 and D2 proteins was detected in 54 of 165 (33%) and 30 of 165 (18%) of the MM patients, respectively. Of note, cyclin D1 or D2 proteins were undetectable in 41% of the samples. High levels of cyclin D1 protein were strongly associated with the presence of t(11;14) or 11q gains. Cyclin D2 protein was detected in all the cases bearing t(14;16), but in only 24% of patients with t(4;14). The presence of cyclin D2 was associated with shorter overall survival (hazard ratio =2.14; P=0.017), although patients expressing cyclin D2 protein, but without 1q gains, had a favorable prognosis. In conclusion, although one of the cyclins D is overexpressed at the mRNA level in almost all MM patients, in approximately half of the patients this does not translate into detectable protein. This suggests that cyclins D could not play an oncogenic role in a proportion of patients with MM (clinicaltrials gov. identifier: NCT01916252).

Evolution of monoclonal gammopathy of undetermined significance in patients treated with JAK inhibitors for rheumatic diseases: data from the MAJIK-SFR registry

OBJECTIVE

Monoclonal gammopathy of undetermined significance (MGUS) is common, but there are scarce data regarding the effect of DMARDs on this premalignant condition. We aimed to evaluate the impact of JAK inhibitors (JAKis) on MGUS when initiated for an active rheumatic disease.

METHODS

Patients with monoclonal abnormality prior to JAKi initiation for an active rheumatic disease were identified through the MAJIK-SFR Registry, a French multicentre prospective study. Clinical and biological data were collected using a standardized case report form.

RESULTS

Twenty patients were identified with a mean age of 65 years and a diagnosis of RA (n = 15), PsA (n = 3), and axial SpA (n = 2). The JAKi prescribed was baricitinib (n = 9), tofacitinib (n = 6) or upadacitinib (n = 5), with a mean duration of 15.5 months. Seventeen patients had individualized serum monoclonal protein (IgG kappa n = 9; IgG lambda n = 4; IgM kappa n = 3; IgA lambda n = 1) ranging from 0.16 to 2.3 g/dl, and three patients did not have an initial measurable spike but they had a positive serum immunofixation. With a follow-up of 4-28 months, the serum monoclonal protein level decreased in 8 of 17 patients (47%), remained stable in 8 patients (47%) and increased in 1 patient (6%). The maximal decrease observed was an initial IgG kappa of 2.3 g/dl, decreasing to 0.2 g/dl at month 14.

CONCLUSION

This study provides reassuring and promising data on MGUS evolution in patients treated with JAKis for rheumatic diseases, which may guide the choice of treatment in patients with both conditions.

Different evasion strategies in multiple myeloma

Multiple myeloma is the second most common malignant hematologic malignancy which evolved different strategies for immune escape from the host immune surveillance and drug resistance, including uncontrolled proliferation of malignant plasma cells in the bone marrow, genetic mutations, or deletion of tumor antigens to escape from special targets and so. Therefore, it is a big challenge to efficiently treat multiple myeloma patients. Despite recent applications of immunomodulatory drugs (IMiDS), protease inhibitors (PI), targeted monoclonal antibodies (mAb), and even hematopoietic stem cell transplantation (HSCT), it remains hardly curable. Summarizing the possible evasion strategies can help design specific drugs for multiple myeloma treatment. This review aims to provide an integrative overview of the intrinsic and extrinsic evasion mechanisms as well as recently discovered microbiota utilized by multiple myeloma for immune evasion and drug resistance, hopefully providing a theoretical basis for the rational design of specific immunotherapies or drug combinations to prevent the uncontrolled proliferation of MM, overcome drug resistance and improve patient survival.

Isoliquiritigenin, a potential therapeutic agent for treatment of inflammation-associated diseases

ETHNOPHARMACOLOGICAL RELEVANCE

Licorice is a medicinal herb with a 2000-year history of applications in traditional Chinese medicine. Isoliquiritigenin (ISL) is a bioactive chalcone compound isolated from licorice. It has attracted increasing attention in recent years due to its excellent anti-inflammatory activity.

AIM OF THE STUDY

This study is to provide a comprehensive summary of the anti-inflammatory activity of ISL and the underlying molecular mechanisms, and discuss new insights for its potential clinical applications as an anti-inflammation agent.

MATERIALS AND METHODS

We examined literatures published in the past twenty years from PubMed, Research Gate, Web of Science, Google Scholar, and SciFinder, with single or combined key words of "isoliquiritigenin", "inflammation", and "anti-inflammatory".

RESULTS

ISL elicits its anti-inflammatory activity by mediating various cellular processes. It inhibits the upstream of the nuclear factor kappa B (NF-κB) pathway and activates the nuclear factor erythroid related factor 2 (Nrf2) pathway. In addition, it suppresses the NOD-like receptor protein 3 (NLRP3) pathway and restrains the mitogen-activated protein kinase (MAPK) pathway.

CONCLUSIONS

Current studies indicate a great therapeutical potential of ISL as a drug candidate for treatment of inflammation-associated diseases. However, the pharmacokinetics, biosafety, and bioavailability of ISL remain to be further investigated.

HAPLN1 matrikine: a bone marrow homing factor linked to poor outcomes in patients with MM

The bone marrow (BM) microenvironment is critical for dissemination, growth, and survival of multiple myeloma (MM) cells. Homing of myeloma cells to the BM niche is a crucial step in MM dissemination, but the mechanisms involved are incompletely understood. In particular, any role of matrikines, neofunctional peptides derived from extracellular matrix proteins, remains unknown. Here, we report that a matrikine derived from hyaluronan and proteoglycan link protein 1 (HAPLN1) induces MM cell adhesion to the BM stromal components, such as fibronectin, endothelial cells, and stromal cells and, furthermore, induces their chemotactic and chemokinetic migration. In a mouse xenograft model, we show that MM cells preferentially home to HAPLN1 matrikine-conditioned BM. The transcription factor STAT1 is activated by HAPLN1 matrikine and is necessary to induce MM cell adhesion, migration, migration-related genes, and BM homing. STAT1 activation is mediated by interferon beta (IFN-β), which is induced by NF-κB after stimulation by HAPLN1 matrikine. Finally, we also provide evidence that higher levels of HAPLN1 in BM samples correlate with poorer progression-free survival of patients with newly diagnosed MM. These data reveal that a matrikine present in the BM microenvironment acts as a chemoattractant, plays an important role in BM homing of MM cells via NF-κB-IFN-β-STAT1 signaling, and may help identify patients with poor outcomes. This study also provides a mechanistic rationale for targeting HAPLN1 matrikine in MM therapy.

Good Cop, Bad Cop: Profiling the Immune Landscape in Multiple Myeloma

Multiple myeloma (MM) is a dyscrasia of plasma cells (PCs) characterized by abnormal immunoglobulin (Ig) production. The disease remains incurable due to a multitude of mutations and structural abnormalities in MM cells, coupled with a favorable microenvironment and immune suppression that eventually contribute to the development of drug resistance. The bone marrow microenvironment (BMME) is composed of a cellular component comprising stromal cells, endothelial cells, osteoclasts, osteoblasts, and immune cells, and a non-cellular component made of the extracellular matrix (ECM) and the liquid milieu, which contains cytokines, growth factors, and chemokines. The bone marrow stromal cells (BMSCs) are involved in the adhesion of MM cells, promote the growth, proliferation, invasion, and drug resistance of MM cells, and are also crucial in angiogenesis and the formation of lytic bone lesions. Classical immunophenotyping in combination with advanced immune profiling using single-cell sequencing technologies has enabled immune cell-specific gene expression analysis in MM to further elucidate the roles of specific immune cell fractions from peripheral blood and bone marrow (BM) in myelomagenesis and progression, immune evasion and exhaustion mechanisms, and development of drug resistance and relapse. The review describes the role of BMME components in MM development and ongoing clinical trials using immunotherapeutic approaches.

High-content microscopy reveals a morphological signature of bortezomib resistance

Drug resistance is a challenge in anticancer therapy. In many cases, cancers can be resistant to the drug prior to exposure, that is, possess intrinsic drug resistance. However, we lack target-independent methods to anticipate resistance in cancer cell lines or characterize intrinsic drug resistance without a priori knowledge of its cause. We hypothesized that cell morphology could provide an unbiased readout of drug resistance. To test this hypothesis, we used HCT116 cells, a mismatch repair-deficient cancer cell line, to isolate clones that were resistant or sensitive to bortezomib, a well-characterized proteasome inhibitor and anticancer drug to which many cancer cells possess intrinsic resistance. We then expanded these clones and measured high-dimensional single-cell morphology profiles using Cell Painting, a high-content microscopy assay. Our imaging- and computation-based profiling pipeline identified morphological features that differed between resistant and sensitive cells. We used these features to generate a morphological signature of bortezomib resistance. We then employed this morphological signature to analyze a set of HCT116 clones (five resistant and five sensitive) that had not been included in the signature training dataset, and correctly predicted sensitivity to bortezomib in seven cases, in the absence of drug treatment. This signature predicted bortezomib resistance better than resistance to other drugs targeting the ubiquitin-proteasome system, indicating specificity for mechanisms of resistance to bortezomib. Our results establish a proof-of-concept framework for the unbiased analysis of drug resistance using high-content microscopy of cancer cells, in the absence of drug treatment.

Molecular and immunological mechanisms of clonal evolution in multiple myeloma

Multiple myeloma (MM) is a hematologic malignancy characterized by the proliferation of clonal plasma cells in the bone marrow (BM). It is known that early genetic mutations in post-germinal center B/plasma cells are the cause of myelomagenesis. The acquisition of additional chromosomal abnormalities and distinct mutations further promote the outgrowth of malignant plasma cell populations that are resistant to conventional treatments, finally resulting in relapsed and therapy-refractory terminal stages of MM. In addition, myeloma cells are supported by autocrine signaling pathways and the tumor microenvironment (TME), which consists of diverse cell types such as stromal cells, immune cells, and components of the extracellular matrix. The TME provides essential signals and stimuli that induce proliferation and/or prevent apoptosis. In particular, the molecular pathways by which MM cells interact with the TME are crucial for the development of MM. To generate successful therapies and prevent MM recurrence, a thorough understanding of the molecular mechanisms that drive MM progression and therapy resistance is essential. In this review, we summarize key mechanisms that promote myelomagenesis and drive the clonal expansion in the course of MM progression such as autocrine signaling cascades, as well as direct and indirect interactions between the TME and malignant plasma cells. In addition, we highlight drug-resistance mechanisms and emerging therapies that are currently tested in clinical trials to overcome therapy-refractory MM stages.

Inhibition of VCP modulates NF-κB signaling pathway to suppress multiple myeloma cell proliferation and osteoclast differentiation

Multiple myeloma (MM) is the second most common hematological malignancy, in which the dysfunction of the ubiquitin-proteasome pathway is associated with the pathogenesis. The valosin containing protein (VCP)/p97, a member of the AAA+ ATPase family, possesses multiple functions to regulate the protein quality control including ubiquitin-proteasome system and molecular chaperone. VCP is involved in the occurrence and development of various tumors while still elusive in MM. VCP inhibitors have gradually shown great potential for cancer treatment. This study aims to identify if VCP is a therapeutic target in MM and confirm the effect of a novel inhibitor of VCP (VCP20) on MM. We found that VCP was elevated in MM patients and correlated with shorter survival in clinical TT2 cohort. Silencing VCP using siRNA resulted in decreased MM cell proliferation via NF-κB signaling pathway. VCP20 evidently inhibited MM cell proliferation and osteoclast differentiation. Moreover, exosomes containing VCP derived from MM cells partially alleviated the inhibitory effect of VCP20 on cell proliferation and osteoclast differentiation. Mechanism study revealed that VCP20 inactivated the NF-κB signaling pathway by inhibiting ubiquitination degradation of IκBα. Furthermore, VCP20 suppressed MM cell proliferation, prolonged the survival of MM model mice and improved bone destruction in vivo. Collectively, our findings suggest that VCP is a novel target in MM progression. Targeting VCP with VCP20 suppresses malignancy progression of MM via inhibition of NF-κB signaling pathway.

Characterization and application of a lactate and branched chain amino acid metabolism related gene signature in a prognosis risk model for multiple myeloma

BACKGROUND

About 10% of hematologic malignancies are multiple myeloma (MM), an untreatable cancer. Although lactate and branched-chain amino acids (BCAA) are involved in supporting various tumor growth, it is unknown whether they have any bearing on MM prognosis.

METHODS

MM-related datasets (GSE4581, GSE136337, and TCGA-MM) were acquired from the Gene Expression Omnibus (GEO) database and the Cancer Genome Atlas (TCGA) database. Lactate and BCAA metabolism-related subtypes were acquired separately via the R package "ConsensusClusterPlus" in the GSE4281 dataset. The R package "limma" and Venn diagram were both employed to identify lactate-BCAA metabolism-related genes. Subsequently, a lactate-BCAA metabolism-related prognostic risk model for MM patients was constructed by univariate Cox, Least Absolute Shrinkage and Selection Operator (LASSO), and multivariate Cox regression analyses. The gene set enrichment analysis (GSEA) and R package "clusterProfiler"were applied to explore the biological variations between two groups. Moreover, single-sample gene set enrichment analysis (ssGSEA), Microenvironment Cell Populations-counter (MCPcounte), and xCell techniques were applied to assess tumor microenvironment (TME) scores in MM. Finally, the drug's IC50 for treating MM was calculated using the "oncoPredict" package, and further drug identification was performed by molecular docking.

RESULTS

Cluster 1 demonstrated a worse prognosis than cluster 2 in both lactate metabolism-related subtypes and BCAA metabolism-related subtypes. 244 genes were determined to be involved in lactate-BCAA metabolism in MM. The prognostic risk model was constructed by CKS2 and LYZ selected from this group of genes for MM, then the prognostic risk model was also stable in external datasets. For the high-risk group, a total of 13 entries were enriched. 16 entries were enriched to the low-risk group. Immune scores, stromal scores, immune infiltrating cells (except Type 17 T helper cells in ssGSEA algorithm), and 168 drugs'IC50 were statistically different between two groups. Alkylating potentially serves as a new agent for MM treatment.

CONCLUSIONS

CKS2 and LYZ were identified as lactate-BCAA metabolism-related genes in MM, then a novel prognostic risk model was built by using them. In summary, this research may uncover novel characteristic genes signature for the treatment and prognostic of MM.

The Leucine-Rich α2-Glycoprotein-1 Levels in Patients with Multiple Myeloma

INTRODUCTION

Angiogenesis is considered important in the pathogenesis of multiple myeloma (MM), as well as in the targeted treatment of the disease. Leucine-rich α2-glycoprotein 1 (LRG1) is a protein that participates in angiogenesis and its effect on solid organ tumors has been investigated recently. This study aimed to investigate the relationship between MM and LRG1.

METHODS

The MM patients who admitted to Hatay Mustafa Kemal University Hematology Clinic between September 2021 and October 2022 were included in the study. The study consists of a total of 4 groups: newly diagnosed MM (NDMM), relapsed refractory MM (RRMM), MM in remission (Rem-MM), and control group. Demographic data were retrieved from hospital records. Blood samples of our study groups were centrifuged at 1,500 × g for 10 min and serum was collected. LRG1, IL-6, IL-8, TGF-β1, HIF-1α, FGF-2, and VEGF levels were analyzed in all groups by ELISA method, and statistical analysis was performed.

RESULTS

A total of 112 individuals, including NDMM (n: 27), RRMM (n: 18), Rem-MM (n: 42), and control group (n: 25), were enrolled in the study. Based on the analyses, the NDMM group exhibited significantly elevated levels of LRG1 (p < 0.001), TGF-1 (p < 0.001), and HIF-1α (p = 0.046, p < 0.001, and p = 0.003 compared to the RRMM, Rem-MM, and control groups, respectively) compared to the other groups. LRG1 levels were positively correlated with creatinine (r: 0.363, p = 0.001), calcium (r: 0.344, p = 0.001), total protein (r: 0.473, p < 0.001), erythrocyte sedimentation rate (r: 0.547, p < 0.001), lactate dehydrogenase (r: 0.321, p = 0.003), beta-2-microglobulin (r: 0.312, p = 0.017), IL-6 (r: 0.478, p < 0.001), IL-8 (r: 0.240, p = 0.03), TGF-β1 (r: 0.521, p < 0.001), and HIF-1α (r: 0.321, p = 0.003) levels and were negatively correlated with hemoglobin (r: -0.512, p < 0.001) and albumin (r: -0.549, p < 0.001) levels. Receiver operating characteristics (ROC) analysis revealed the association of LRG1 with the highest AUC value of 0.959 (95% CI: 0.904-1, p < 0.001) and the optimal cut-off value of 534.95 ng/mL (sensitivity: 93% and specificity: 99%) in the NDMM group compared to the control group.

CONCLUSION

In this study, providing data for the first time on LRG1 levels in the setting of MM. LRG1 levels were found to be significantly higher in NDMM patients and in our study discriminate this patient population from RRMM, Rem-MM, and normal controls. Therefore, LRG1 seems to a potential biomarker that should be evaluated in future studies addressing the diagnosis, staging, follow-up, prognosis, and treatment target of MM.

Emerging Strategies in 3D Culture Models for Hematological Cancers

In vitro cell cultures are fundamental and necessary tools in cancer research and personalized drug discovery. Currently, most cells are cultured using two-dimensional (2D) methods, and drug testing is mainly performed in animal models. However, new and improved methods that implement three-dimensional (3D) cell-culturing techniques provide compelling evidence that more advanced experiments can be performed, yielding valuable new insights. In 3D cell-culture experiments, the cell environment can be manipulated to mimic the complexity and dynamicity of the human tissue microenvironment, possibly leading to more accurate representations of cell-to-cell interactions, tumor biology, and predictions of drug response. The 3D cell cultures can also potentially provide alternative ways to study hematological cancers and are expected to eventually bridge the gap between 2D cell culture and animal models. The present review provides an overview of the complexity of the lymphoid microenvironment and a summary of the currently used 3D models that aim at recreating it for hematological cancer research. We here dissect the differences and challenges between, and potential advantages of, different culture methods and present our vision of the most promising future strategies in the hematological field.

Regulation of miRNA expression by α4β1 integrin-dependent multiple myeloma cell adhesion

The α4β1 integrin regulates the trafficking of multiple myeloma (MM) cells and contributes to MM disease progression. MicroRNAs (miRNAs) can have both tumor suppressor and oncogenic roles and thus are key controllers of tumor evolution, and have been associated with different phases of MM pathogenesis. Using small RNAseq analysis, we show here that α4β1-dependent MM cell adhesion regulates the expression of forty different miRNAs, therefore expanding our current view of the α4β1 involvement in MM cell biology. Specific upregulation of miR-324-5p and miR-331-3p in cells attached to α4β1 ligands was confirmed upon silencing the α4 integrin subunit, and their increased levels found to be dependent on Erk1/2- and PI3K-Akt-, but not Src-dependent signaling. Enhanced miR-324-5p expression upon α4β1-mediated MM cell adhesion aimed the hedgehog (Hh) component SMO, revealing that the miR-324-5p-SMO module represents a α4β1-regulated pathway that could control Hh-dependent cellular responses in myeloma. Our results open new therapy research avenues around the α4β1 contribution to MM progression that deserve to be investigated.

Serum NMR-Based Metabolomics Profiling Identifies Lipoprotein Subfraction Variables and Amino Acid Reshuffling in Myeloma Development and Progression

Multiple myeloma (MM) is an incurable hematological cancer. It is preceded by monoclonal gammopathy of uncertain significance (MGUS)-an asymptomatic phase. It has been demonstrated that early detection increases the 5-year survival rate. However, blood-based biomarkers that enable early disease detection are lacking. Metabolomic and lipoprotein subfraction variable profiling is gaining traction to expand our understanding of disease states and, more specifically, for identifying diagnostic markers in patients with hematological cancers. This study aims to enhance our understanding of multiple myeloma (MM) and identify candidate metabolites, allowing for a more effective preventative treatment. Serum was collected from 25 healthy controls, 20 patients with MGUS, and 30 patients with MM. 1H-NMR (Nuclear Magnetic Resonance) spectroscopy was utilized to evaluate serum samples. The metabolite concentrations were examined using multivariate, univariate, and pathway analysis. Metabolic profiles of the MGUS patients revealed lower levels of alanine, lysine, leucine but higher levels of formic acid when compared to controls. However, metabolic profiling of MM patients, compared to controls, exhibited decreased levels of total Apolipoprotein-A1, HDL-4 Apolipoprotein-A1, HDL-4 Apolipoprotein-A2, HDL Free Cholesterol, HDL-3 Cholesterol and HDL-4 Cholesterol. Lastly, metabolic comparison between MGUS to MM patients primarily indicated alterations in lipoproteins levels: Total Cholesterol, HDL Cholesterol, HDL Free Cholesterol, Total Apolipoprotein-A1, HDL Apolipoprotein-A1, HDL-4 Apolipoprotein-A1 and HDL-4 Phospholipids. This study provides novel insights into the serum metabolic and lipoprotein subfraction changes in patients as they progress from a healthy state to MGUS to MM, which may allow for earlier clinical detection and treatment.

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.

Hypophosphatemia in Patients With Multiple Myeloma

Hypophosphatemia is among the most common electrolyte abnormalities, especially among patients with underlying malignancies, and is frequently associated with adverse prognoses. Phosphorus levels are regulated through a number of mechanisms, including parathyroid hormone (PTH), fibroblast growth factor-23 (FGF-23), vitamin D, and other electrolyte levels themselves. Clinically, the findings are nonspecific, and the diagnosis is frequently delayed. This article is a narrative literature review. The PubMed database was searched for relevant articles pertaining to hypophosphatemia causes and consequences in patients suffering from multiple myeloma. We found a variety of causes of hypophosphatemia in patients with multiple myeloma. Tumor-induced osteopenia, although more common among patients with small squamous cell carcinomas, can occur with multiple myeloma as well. Additionally, both light chains themselves and medications can trigger Fanconi syndrome, which leads to phosphorus wasting by the kidney. Bisphosphonates, in addition to being a possible cause of Fanconi syndrome, lead to a decrease in calcium levels, which then stimulates parathyroid hormone (PTH) release, predisposing the patient to significant hypophosphatemia. Additionally, many of the more modern medications used to manage multiple myeloma have been associated with hypophosphatemia. A better understanding of those mechanisms may give clinicians a clearer idea of which patients may need more frequent screening as well as what the potential triggers in the individual patient may be.

Single-cell technologies in multiple myeloma: new insights into disease pathogenesis and translational implications

Multiple myeloma (MM) is a hematological malignancy characterized by clonal proliferation of plasma cells. Although therapeutic advances have been made to improve clinical outcomes and to prolong patients' survival in the past two decades, MM remains largely incurable. Single-cell sequencing (SCS) is a powerful method to dissect the cellular and molecular landscape at single-cell resolution, instead of providing averaged results. The application of single-cell technologies promises to address outstanding questions in myeloma biology and has revolutionized our understanding of the inter- and intra-tumor heterogeneity, tumor microenvironment, and mechanisms of therapeutic resistance in MM. In this review, we summarize the recently developed SCS methodologies and latest MM research progress achieved by single-cell profiling, including information regarding the cancer and immune cell landscapes, tumor heterogeneities, underlying mechanisms and biomarkers associated with therapeutic response and resistance. We also discuss future directions of applying transformative SCS approaches with contribution to clinical translation.

Communication between bone marrow mesenchymal stem cells and multiple myeloma cells: Impact on disease progression

Multiple myeloma (MM) is a hematological malignancy characterized by the accumulation of immunoglobulin-secreting clonal plasma cells at the bone marrow (BM). The interaction between MM cells and the BM microenvironment, and specifically BM mesenchymal stem cells (BM-MSCs), has a key role in the pathophysiology of this disease. Multiple data support the idea that BM-MSCs not only enhance the proliferation and survival of MM cells but are also involved in the resistance of MM cells to certain drugs, aiding the progression of this hematological tumor. The relation of MM cells with the resident BM-MSCs is a two-way interaction. MM modulate the behavior of BM-MSCs altering their expression profile, proliferation rate, osteogenic potential, and expression of senescence markers. In turn, modified BM-MSCs can produce a set of cytokines that would modulate the BM microenvironment to favor disease progression. The interaction between MM cells and BM-MSCs can be mediated by the secretion of a variety of soluble factors and extracellular vesicles carrying microRNAs, long non-coding RNAs or other molecules. However, the communication between these two types of cells could also involve a direct physical interaction through adhesion molecules or tunneling nanotubes. Thus, understanding the way this communication works and developing strategies to interfere in the process, would preclude the expansion of the MM cells and might offer alternative treatments for this incurable disease.

The discrete roles of individual FOXO transcription factor family members in B-cell malignancies

Forkhead box (FOX) class O (FOXO) proteins are a dynamic family of transcription factors composed of four family members: FOXO1, FOXO3, FOXO4 and FOXO6. As context-dependent transcriptional activators and repressors, the FOXO family regulates diverse cellular processes including cell cycle arrest, apoptosis, metabolism, longevity and cell fate determination. A central pathway responsible for negative regulation of FOXO activity is the phosphatidylinositol-3-kinase (PI3K)-AKT signalling pathway, enabling cell survival and proliferation. FOXO family members can be further regulated by distinct kinases, both positively (e.g., JNK, AMPK) and negatively (e.g., ERK-MAPK, CDK2), with additional post-translational modifications further impacting on FOXO activity. Evidence has suggested that FOXOs behave as 'bona fide' tumour suppressors, through transcriptional programmes regulating several cellular behaviours including cell cycle arrest and apoptosis. However, an alternative paradigm has emerged which indicates that FOXOs operate as mediators of cellular homeostasis and/or resistance in both 'normal' and pathophysiological scenarios. Distinct FOXO family members fulfil discrete roles during normal B cell maturation and function, and it is now clear that FOXOs are aberrantly expressed and mutated in discrete B-cell malignancies. While active FOXO function is generally associated with disease suppression in chronic lymphocytic leukemia for example, FOXO expression is associated with disease progression in diffuse large B cell lymphoma, an observation also seen in other cancers. The opposing functions of the FOXO family drives the debate about the circumstances in which FOXOs favour or hinder disease progression, and whether targeting FOXO-mediated processes would be effective in the treatment of B-cell malignancies. Here, we discuss the disparate roles of FOXO family members in B lineage cells, the regulatory events that influence FOXO function focusing mainly on post-translational modifications, and consider the potential for future development of therapies that target FOXO activity.

High-content microscopy reveals a morphological signature of bortezomib resistance

Drug resistance is a challenge in anticancer therapy, particularly with targeted therapeutics and cytotoxic compounds. In many cases, cancers can be resistant to the drug prior to exposure, i.e., possess intrinsic drug resistance. However, we lack target-independent methods to anticipate resistance in cancer cell lines or characterize intrinsic drug resistance without a priori knowledge of its cause. We hypothesized that cell morphology could provide an unbiased readout of drug sensitivity prior to treatment. We therefore isolated clonal cell lines that were either sensitive or resistant to bortezomib, a well-characterized proteasome inhibitor and anticancer drug to which many cancer cells possess intrinsic resistance. We then measured high-dimensional single-cell morphology profiles using Cell Painting, a high-content microscopy assay. Our imaging- and computation-based profiling pipeline identified morphological features typically different between resistant and sensitive clones. These features were compiled to generate a morphological signature of bortezomib resistance, which correctly predicted the bortezomib treatment response in seven of ten cell lines not included in the training dataset. This signature of resistance was specific to bortezomib over other drugs targeting the ubiquitin-proteasome system. Our results provide evidence that intrinsic morphological features of drug resistance exist and establish a framework for their identification.

Metabolic changes underlying drug resistance in the multiple myeloma tumor microenvironment

Multiple myeloma (MM) is characterized by the clonal expansion of malignant plasma cells in the bone marrow (BM). MM remains an incurable disease, with the majority of patients experiencing multiple relapses from different drugs. The MM tumor microenvironment (TME) and in particular bone-marrow stromal cells (BMSCs) play a crucial role in the development of drug resistance. Metabolic reprogramming is emerging as a hallmark of cancer that can potentially be exploited for cancer treatment. Recent studies show that metabolism is further adjusted in MM cells during the development of drug resistance. However, little is known about the role of BMSCs in inducing metabolic changes that are associated with drug resistance. In this Perspective, we summarize current knowledge concerning the metabolic reprogramming of MM, with a focus on those changes associated with drug resistance to the proteasome inhibitor Bortezomib (BTZ). In addition, we present proof-of-concept fluxomics (glucose isotope-tracing) and Seahorse data to show that co-culture of MM cells with BMSCs skews the metabolic phenotype of MM cells towards a drug-resistant phenotype, with increased oxidative phosphorylation (OXPHOS), serine synthesis pathway (SSP), TCA cycle and glutathione (GSH) synthesis. Given the crucial role of BMSCs in conveying drug resistance, insights into the metabolic interaction between MM and BMSCs may ultimately aid in the identification of novel metabolic targets that can be exploited for therapy.

The roles of bone remodeling in normal hematopoiesis and age-related hematological malignancies

Prior research establishing that bone interacts in coordination with the bone marrow microenvironment (BMME) to regulate hematopoietic homeostasis was largely based on analyses of individual bone-associated cell populations. Recent advances in intravital imaging has suggested that the expansion of hematopoietic stem cells (HSCs) and acute myeloid leukemia cells is restricted to bone marrow microdomains during a distinct stage of bone remodeling. These findings indicate that dynamic bone remodeling likely imposes additional heterogeneity within the BMME to yield differential clonal responses. A holistic understanding of the role of bone remodeling in regulating the stem cell niche and how these interactions are altered in age-related hematological malignancies will be critical to the development of novel interventions. To advance this understanding, herein, we provide a synopsis of the cellular and molecular constituents that participate in bone turnover and their known connections to the hematopoietic compartment. Specifically, we elaborate on the coupling between bone remodeling and the BMME in homeostasis and age-related hematological malignancies and after treatment with bone-targeting approaches. We then discuss unresolved questions and ambiguities that remain in the field.

Ectopic CH60 mediates HAPLN1-induced cell survival signaling in multiple myeloma

Multiple myeloma (MM), the second most common hematological malignancy, is generally considered incurable because of the development of drug resistance. We previously reported that hyaluronan and proteoglycan link protein 1 (HAPLN1) produced by stromal cells induces activation of NF-κB, a tumor-supportive transcription factor, and promotes drug resistance in MM cells. However, the identity of the cell surface receptor that detects HAPLN1 and thereby engenders pro-tumorigenic signaling in MM cells remains unknown. Here, we performed an unbiased cell surface biotinylation assay and identified chaperonin 60 (CH60) as the direct binding partner of HAPLN1 on MM cells. Cell surface CH60 specifically interacted with TLR4 to evoke HAPLN1-induced NF-κB signaling, transcription of anti-apoptotic genes, and drug resistance in MM cells. Collectively, our findings identify a cell surface CH60-TLR4 complex as a HAPLN1 receptor and a potential molecular target to overcome drug resistance in MM cells.

A novel ferroptosis-related gene signature for predicting prognosis in multiple myeloma

Background

Multiple myeloma (MM) is a highly malignant hematological tumor with a poor overall survival (OS). Due to the high heterogeneity of MM, it is necessary to explore novel markers for the prognosis prediction for MM patients. Ferroptosis is a form of regulated cell death, playing a critical role in tumorigenesis and cancer progression. However, the predictive role of ferroptosis-related genes (FRGs) in MM prognosis remains unknown.

Methods

This study collected 107 FRGs previously reported and utilized the least absolute shrinkage and selection operator (LASSO) cox regression model to construct a multi-genes risk signature model upon FRGs. The ESTIMATE algorithm and immune-related single-sample gene set enrichment analysis (ssGSEA) were carried out to evaluate immune infiltration level. Drug sensitivity was assessed based on the Genomics of Drug Sensitivity in Cancer database (GDSC). Then the synergy effect was determined with Cell counting kit-8 (CCK-8) assay and SynergyFinder software.

Results

A 6-gene prognostic risk signature model was constructed, and MM patients were divided into high and low risk groups. Kaplan-Meier survival curves showed that patients in the high risk group had significantly reduced OS compared with patients in the low risk group. Besides, the risk score was an independent predictor for OS. Receiver operating characteristic (ROC) curve analysis confirmed the predictive capacity of the risk signature. Combination of risk score and ISS stage had better prediction performance. Enrichment analysis revealed immune response, MYC, mTOR, proteasome and oxidative phosphorylation were enriched in high risk MM patients. We found high risk MM patients had lower immune scores and immune infiltration levels. Moreover, further analysis found that MM patients in high risk group were sensitive to bortezomib and lenalidomide. At last, the results of the in vitro experiment showed that ferroptosis inducers (RSL3 and ML162) may synergistically enhance the cytotoxicity of bortezomib and lenalidomide against MM cell line RPMI-8226.

Conclusion

This study provides novel insights into roles of ferroptosis in MM prognosis prediction, immune levels and drug sensitivity, which complements and improves current grading systems.

Monoclonal Gammopathies and the Bone Marrow Microenvironment: From Bench to Bedside and Then Back Again

Multiple myeloma (MM) is an incurable hematologic malignancy characterized by a multistep evolutionary pathway, with an initial phase called monoclonal gammopathy of undetermined significance (MGUS), potentially evolving into the symptomatic disease, often preceded by an intermediate phase called "smoldering" MM (sMM). From a biological point of view, genomic alterations (translocations/deletions/mutations) are already present at the MGUS phase, thus rendering their role in disease evolution questionable. On the other hand, we currently know that changes in the bone marrow microenvironment (TME) could play a key role in MM evolution through a progressive shift towards a pro-inflammatory and immunosuppressive shape, which may drive cancer progression as well as clonal plasma cells migration, proliferation, survival, and drug resistance. Along this line, the major advancement in MM patients' survival has been achieved by the introduction of microenvironment-oriented drugs (including immunomodulatory drugs and monoclonal antibodies). In this review, we summarized the role of the different components of the TME in MM evolution from MGUS as well as potential novel therapeutic targets/opportunities.

LAMP5 may promote MM progression by activating p38

Multiple myeloma (MM) is the second most common tumor of the hematologic system. MM remains incurable at this time. In this study, we used bioinformatics analysis to find key genes in the pathogenesis of MM. We first found that Lysosome associated membrane protein 5 (LAMP5) expression was sequentially increased in healthy donors (HD), monoclonal gammopathy of undetermined significance (MGUS), smoldering multiple myeloma (SMM) and newly diagnosed MM (NDMM), relapsed MM (RMM). We collected bone marrow from patients with NDMM, HD and post-treatment MM (PTMM) and performed qPCR analysis of LAMP5, and found that the expression of LAMP5 is stronger in NDMM than in HD, and decreases after treatment. Western blotting assay also found more expression of LAMP5 in NDMM than in HD. Patients with high LAMP5 expression have a higher DS (Durie-Salmon) stage and worse prognosis. We next verified the expression of LAMP5 in four MM cell lines and silenced LAMP5 expression in RPMI-8226 and AMO-1, and explored the effects of LAMP5 silencing on MM cell apoptosis and cell cycle by flow cytometry and western blotting. Knockdown of LAMP5 promoted apoptosis in MM cells, but had no effect on the cell cycle. Mechanistically, LAMP5 may exert its pro-tumor effects in MM in part through activation of p38 protein. We screened LAMP5 for the first time as a key gene for MM progression and recurrence, and found that LAMP5 may exert its pro-tumor effects in MM through activation of p38 protein.

miRNAs and Multiple Myeloma: Focus on the Pathogenesis, Prognosis, and Drug Resistance

Multiple myeloma (MM) produces clonal plasma cells and aberrant monoclonal antibody accumulation in patients' bone marrow (BM). Around 1% of all cancers and 13% of hematological malignancies are caused by MM, making it one of the most common types of cancer. Diagnostic and therapeutic methods for managing MM are currently undergoing extensive research. MicroRNAs (miRNAs) are short noncoding RNAs that reduce or inhibit the translation of their target mRNA after transcription. Because miRNAs play an influential role in how myeloma develops, resources, and becomes resistant to drugs, miRNA signatures may be used to diagnose, do prognosis, and treat the myeloma response. Consequently, researchers have investigated the levels of miRNA in plasma cells from MM patients and developed tools to test whether they directly impacted tumor growth. This review discusses the latest discoveries in miRNA science and their role in the development of MM. We also emphasize the potential applications of miRNAs to diagnose, prognosticate, and treat MM in the future.

Investigation of Rare Non-Coding Variants in Familial Multiple Myeloma

Multiple myeloma (MM) is a plasma cell malignancy whereby a single clone of plasma cells over-propagates in the bone marrow, resulting in the increased production of monoclonal immunoglobulin. While the complex genetic architecture of MM is well characterized, much less is known about germline variants predisposing to MM. Genome-wide sequencing approaches in MM families have started to identify rare high-penetrance coding risk alleles. In addition, genome-wide association studies have discovered several common low-penetrance risk alleles, which are mainly located in the non-coding genome. Here, we further explored the genetic basis in familial MM within the non-coding genome in whole-genome sequencing data. We prioritized and characterized 150 upstream, 5' untranslated region (UTR) and 3' UTR variants from 14 MM families, including 20 top-scoring variants. These variants confirmed previously implicated biological pathways in MM development. Most importantly, protein network and pathway enrichment analyses also identified 10 genes involved in mitogen-activated protein kinase (MAPK) signaling pathways, which have previously been established as important MM pathways.

Chimeric antigen receptor T-cell therapy for multiple myeloma

Multiple myeloma (MM) is a malignant plasma cell disorder that remains incurable for most patients, as persistent clonal evolution drives new mutations which confer MM high-risk signatures and resistance to standard care. The past two decades have significantly refashioned the therapeutic options for MM, especially adoptive T cell therapy contributing to impressive response rate and clinical efficacy. Despite great promises achieved from chimeric antigen receptor T-cell (CAR-T) therapy, the poor durability and severe toxicity (cytokine release syndrome and neurotoxicity) are still huge challenges. Therefore, relapsed/refractory multiple myeloma (RRMM), characterized by the nature of clinicopathologic and molecular heterogeneity, is frequently associated with poor prognosis. B Cell Maturation Antigen (BCMA) is the most successful target for CAR-T therapy, and other potential targets either for single-target or dual-target CAR-T are actively being studied in numerous clinical trials. Moreover, mechanisms driving resistance or relapse after CAR-T therapy remain uncharacterized, which might refer to T-cell clearance, antigen escape, and immunosuppressive tumor microenvironment. Engineering CAR T-cell to improve both efficacy and safety continues to be a promising area for investigation. In this review, we aim to describe novel tumor-associated neoantigens for MM, summarize the data from current MM CAR-T clinical trials, introduce the mechanism of disease resistance/relapse after CAR-T infusion, highlight innovations capable of enhanced efficacy and reduced toxicity, and provide potential directions to optimize manufacturing processes.

Molecular Crosstalk between Chromatin Remodeling and Tumor Microenvironment in Multiple Myeloma

Multiple myeloma (MM) is a complex disease driven by numerous genetic and epigenetic alterations that are acquired over time. Despite recent progress in the understanding of MM pathobiology and the availability of innovative drugs, which have pronounced clinical outcome, this malignancy eventually progresses to a drug-resistant lethal stage and, thus, novel therapeutic drugs/models always play an important role in effective management of MM. Modulation of tumor microenvironment is one of the hallmarks of cancer biology, including MM, which affects the myeloma genomic architecture and disease progression subtly through chromatin modifications. The bone marrow niche has a prime role in progression, survival, and drug resistance of multiple myeloma cells. Therefore, it is important to develop means for targeting the ecosystem between multiple myeloma bone marrow microenvironment and chromatin remodeling. Extensive gene expression profile analysis has indeed provided the framework for new risk stratification of MM patients and identifying novel molecular targets and therapeutics. However, key tumor microenvironment factors/immune cells and their interactions with chromatin remodeling complex proteins that drive MM cell growth and progression remain grossly undefined.

The diagnostic and prognostic values of circulating miRNA-1246 in multiple myeloma

BACKGROUND/OBJECTIVE

Bone marrow biopsy, the gold standard for the diagnosis of multiple myeloma (MM), has main limitation of the invasiveness. Here, we explored the diagnostic and prognostic values of circulating miR-1246 in patients with MM.

MATERIAL AND METHODS

Ninety MM patients and 30 healthy donors (control group) were recruited in this study. The expression of miR-1246 in the peripheral blood samples was detected using qPCR. The receiver operating characteristic (ROC) curve was used to assess the diagnostic value of miR-1246 in MM. The Kaplan-Meier survival analyze was performed to evaluate the prognostic value of miR-1246.

RESULTS

The expression level of serum miR-1246 from newly diagnosed MM patients was significantly higher than that of the control group. Circulating miR-1246 level was decreased after treatment in remission patients, but remained high levels in relapsed patients (P < 0.05). ROC analysis demonstrated that miR-1246 showed a high diagnostic value in MM with an area under the curve (AUC) of 0.952, the sensitivity of 87%, and the specificity of 95% [95% confidence interval (CI) 0.902-1.007; P < 0.001]. Kaplan-Meier analysis showed that the progression-free survival (PFS) (14.0 months vs. 26.5 months, P = 0.045) and overall survival (OS) (20.5 months vs. 55.5 months, P = 0.014) were significantly shorter in patients with high miR-1246 expression as compared with those in patients with miR-1246 low expression. Multiple Cox regression model analysis showed that circulating miR-1246 was an independent prognostic factor for PFS (HR 2.786, 95% CI: 1.420-5.467, P = 0.003) and OS (HR 2.995, 95% CI: 1.166-7.689, P = 0.023) in MM patients.

CONCLUSION

This study demonstrates that circulating miR-1246 level is elevated in MM patients, which shows high values in the diagnosis and prognosis prediction in patients with MM.

MSC Senescence-Related Genes Are Associated with Myeloma Prognosis and Lipid Metabolism-Mediated Resistance to Proteasome Inhibitors

BACKGROUND

Complex carcinogenic mechanisms and the existence of tumour heterogeneity in multiple myeloma (MM) prevent the most commonly used staging system from effectively interpreting the prognosis of patients. Since the microenvironment plays an important role in driving tumour development and MM occurs most often in middle-aged and elderly patients, we hypothesize that ageing of bone marrow mesenchymal stem cells (BM-MSCs) may be associated with the progression of MM.

METHODS

In this study, we collected the transcriptome data on MM from The Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO) databases. Differentially expressed genes in both senescent MSCs and MM tumour cells were considered relevant damaged genes. GO and KEGG analyses were applied for functional evaluation. A PPI network was constructed to identify hub genes. Subsequently, we studied the damaged genes that affected the prognosis of MM. Least absolute shrinkage and selection operator (lasso) regression was used to identify the most important features, and a risk model was created. The reliability of the risk model was evaluated with the other 3 GEO validation cohorts. In addition, ROC analysis was used to evaluate the novel risk model. An analysis of immune checkpoint-related genes, tumour immune dysfunction and exclusion (TIDE), and immunophenotypic scoring (IPS) were performed to assess the immune status of risk groups. pRRophetic was utilized to predict the sensitivity to administration of chemotherapeutic agents.

RESULTS

We identified that MAPK, PI3K, and p53 signalling pathways were activated in both senescent MSCs and tumour cells, and we also located hub genes. In addition, we constructed a 14-gene prognostic risk model, which was analysed with the ROC and validated in different datasets. Further analysis revealed significant differences in predicted risk values across the International Staging System (ISS) stage, sex, and 1q21 copy number. A high-risk group with higher immunogenicity was predicted to have low proteasome inhibitor sensitivity and respond poorly to immunotherapy. Lipid metabolism pathways were found to be significantly different between high-risk and low-risk groups. A nomogram was created by combining clinical data, and the optimization model was further improved. Finally, real-time qPCR was used to validate two bortezomib-resistant myeloma cell lines, and the test confirmed that 10 genes were detected to be expressed in resistant cell lines with the same trend as in the high-risk cohort compared to nonresistant cells.

CONCLUSION

Fourteen genes related to ageing in BM-MSCs were associated with the prognosis of MM, and by combining this genotypic information with clinical factors, a promising clinical prognostic model was established.

Targeting CAM-DR and Mitochondrial Transfer for the Treatment of Multiple Myeloma

The prognosis of patients with multiple myeloma (MM) has improved dramatically with the introduction of new therapeutic drugs, but the disease eventually becomes drug-resistant, following an intractable and incurable course. A myeloma niche (MM niche) develops in the bone marrow microenvironment and plays an important role in the drug resistance mechanism of MM. In particular, adhesion between MM cells and bone marrow stromal cells mediated by adhesion molecules induces cell adhesion-mediated drug resistance (CAM-DR). Analyses of the role of mitochondria in cancer cells, including MM cells, has revealed that the mechanism leading to drug resistance involves exchange of mitochondria between cells (mitochondrial transfer) via tunneling nanotubes (TNTs) within the MM niche. Here, we describe the discovery of these drug resistance mechanisms and the identification of promising therapeutic agents primarily targeting CAM-DR, mitochondrial transfer, and TNTs.

Looking into Endoplasmic Reticulum Stress: The Key to Drug-Resistance of Multiple Myeloma?

Multiple myeloma (MM) is the second most common hematologic malignancy, resulting from the clonal proliferation of malignant plasma cells within the bone marrow. Despite significant advances that have been made with novel drugs over the past two decades, MM patients often develop therapy resistance, especially to bortezomib, the first-in-class proteasome inhibitor that was approved for treatment of MM. As highly secretory monoclonal protein-producing cells, MM cells are characterized by uploaded endoplasmic reticulum stress (ERS), and rely heavily on the ERS response for survival. Great efforts have been made to illustrate how MM cells adapt to therapeutic stresses through modulating the ERS response. In this review, we summarize current knowledge on the mechanisms by which ERS response pathways influence MM cell fate and response to treatment. Moreover, based on promising results obtained in preclinical studies, we discuss the prospect of applying ERS modulators to overcome drug resistance in MM.