Dihydrolipoamide dehydrogenase (DLD) is a novel molecular target of bortezomib.

Proteasome inhibitors (PIs), such as bortezomib and calfizomib, were backbone agents in the treatment of multiple myeloma (MM). In this study, we investigated bortezomib interactors in MM cells and identified dihydrolipoamide dehydrogenase (DLD) as a molecular target of bortezomib. DLD catalyzes the oxidation of dihydrolipoamide to form lipoamide, a reaction that also generates NADH. Our data showed that bortezomib bound to DLD and inhibited DLD's enzymatic function in MM cells. DLD knocked down MM cells (DLD-KD) had decreased levels of NADH. Reduced NADH suppressed assembly of proteasome complex in cells. As a result, DLD-KD MM cells had decreased basal-level proteasome activity and were more sensitive to bortezomib. Since PIs were used in many anti-MM regimens in clinics, we found that high expression of DLD correlated with inferior prognosis of MM. Considering the regulatory role of DLD in proteasome assembly, we evaluated DLD targeting therapy in MM cells. DLD inhibitor CPI-613 showed a synergistic anti-MM effect with bortezomib in vitro and in vivo. Overall, our findings elucidated DLD as an alternative molecular target of bortezomib in MM. DLD-targeting might increase MM sensitivity to PIs.

FCGR3A F158V alleles frequency differs in multiple myeloma patients from healthy population.

FCGR3A presents a single nucleotide polymorphism at location 158 (V/F), which affects its binding to the fragment crystallizable (Fc) of antibodies (Abs). FcγRIIIa-158 V allotype has the highest affinity and is associated with a better clinical response to IgG1 monoclonal Abs (mAb) treatment. We compared the allele frequency of FCGR3A-F158V polymorphism in cohorts of patients with B-cell lymphoproliferative disorders, including multiple myeloma (MM), monoclonal gammopathy of undetermined significance (MGUS), non-Hodgkin lymphoma (NHL), and B-cell chronic leukemia (B-CLL). FCGR3A-158F homozygous were enriched and tended to be in MM and MGUS patients, respectively; but neither in B-CLL nor in NHL patients. We identified a significantly lower concentration of CD8 T-cells and resting memory CD4 T-cells in MM patients bone marrow with the F/F genotype, associated with an increase in the macrophage percentage. In contrast, natural killer cells increased in V/V homozygous patients. This suggests a deregulation of the immune microenvironment in FCGR3A-F/F homozygous patients. However, we did not observe difference in response following treatment combining chemotherapy associated or not with daratumumab, an IgG1 mAb direct against CD38. Our findings suggest that FCGR3A F158V polymorphism can regulate the immune environment and affect the development of tumor plasma cells.

Multiple myeloma: unplanned diagnostic pathways and association with risk factors and survival - a nationwide register-based cohort study in Denmark.

BACKGROUND: Multiple myeloma often presents with vague and non-specific symptoms. Many patients are diagnosed in unplanned rather than elective (planned) diagnostic pathways. This study investigates the diagnosis of multiple myeloma in unplanned pathways and the association with patient characteristics, disease profile, and survival. METHODS: We conducted a nationwide register-based study, including all patients diagnosed with multiple myeloma in Denmark in 2014-2018. Patients were categorised as diagnosed in an unplanned pathway if registered with an acute admission within 30 days prior to the multiple myeloma diagnosis and no other previously registered pathway to this diagnosis. Unplanned pathways were compared to all other pathways combined. RESULTS: We included 2,213 patients diagnosed with multiple myeloma, hereof 32% diagnosed in an unplanned pathway. Comorbidity, no prior cancer diagnosis, a history of few visits to the general practitioner (GP), multiple myeloma complications at diagnosis, high-risk cytogenetics, and advanced cancer stage were associated with a higher probability of being diagnosed in an unplanned pathway. For example, 24.4% (95% confidence interval (CI): 21.8-27.0) of patients with low comorbidity (Charlson Comorbidity Index (CCI) score 0) were diagnosed in an unplanned pathway as were 50.9% (95% CI: 45.6-56.1) of patients with high comorbidity (CCI score 3+). For patients with dialysis need at the time of diagnosis the probability was 66.0% (95% CI 54.2-77.8) and 30.9% (95% CI: 28.9-32.9) for patients with no dialysis need. Patients diagnosed in an unplanned pathway had inferior survival (hazard ratio 1.44 (95% CI: 1.26-1.64)). However, this association was not seen in analyses restricted to patients surviving for more than three years. CONCLUSIONS: High comorbidity level, few usual GP visits, advanced disease status at diagnosis, and complications were associated with diagnosis in an unplanned pathway. Further, patients diagnosed in an unplanned pathway had inferior survival. Promoting earlier diagnosis and preventing unplanned pathways may help improve survival in multiple myeloma.

Impact of M-protein detection on the response evaluations of patients undergoing treatment with the IgG-κ monoclonal antibodies daratumumab or isatuximab, and discrepancies between immunofixation electrophoresis (IFE) systems and reagents.

BACKGROUND: Immunofixation electrophoresis (IFE) is the standard method for confirming the presence of a monoclonal protein (M-protein) at multiple myeloma (MM) diagnosis. IFE is also essential at assessment of complete response (CR) and stringent CR during treatment. As the CR assessment is influenced by daratumumab and isatuximab, HYDRASHIFT assays were developed. METHODS: Samples from patients under treatment that included daratumumab or isatuximab were tested and monitored by IFE on the HYDRASYS system using HYDRASHIFT assays (HYDRASYS/HYDRASHIFT) and by IFE on the Epalyzer2 system (Epalyzer). RESULTS: The IFE using HYDRASYS/HYDRASHIFT avoided a false positive caused by drug-related IgG-κ and contributed to accurate assessment of CR. Furthermore, HYDRASYS/HYDRASHIFT detected small M-proteins at early relapse and detected free light chains (FLCs) in patients with renal impairment exhibiting high serum FLCs despite being often missed on Epalyzer. CONCLUSION: Sensitivity and specificity of M-protein detection vary greatly depending on the IFE system and reagents used.

Haplotype analysis identifies functional elements in monoclonal gammopathy of unknown significance.

Genome-wide association studies (GWASs) based on common single nucleotide polymorphisms (SNPs) have identified several loci associated with the risk of monoclonal gammopathy of unknown significance (MGUS), a precursor condition for multiple myeloma (MM). We hypothesized that analyzing haplotypes might be more useful than analyzing individual SNPs, as it could identify functional chromosomal units that collectively contribute to MGUS risk. To test this hypothesis, we used data from our previous GWAS on 992 MGUS cases and 2910 controls from three European populations. We identified 23 haplotypes that were associated with the risk of MGUS at the genome-wide significance level (p < 5 × 10-8) and showed consistent results among all three populations. In 10 genomic regions, strong promoter, enhancer and regulatory element-related histone marks and their connections to target genes as well as genome segmentation data supported the importance of these regions in MGUS susceptibility. Several associated haplotypes affected pathways important for MM cell survival such as ubiquitin-proteasome system (RNF186, OTUD3), PI3K/AKT/mTOR (HINT3), innate immunity (SEC14L1, ZBP1), cell death regulation (BID) and NOTCH signaling (RBPJ). These pathways are important current therapeutic targets for MM, which may highlight the advantage of the haplotype approach homing to functional units.

Multisite distribution of fibrillary inclusions in a patient with light chain proximal tubulopathy: A case report.

RATIONALE: Light chain proximal tubulopathy (LCPT) is a rare form of renal impairment associated with multiple myeloma (MM). LCPT is caused by inclusions formed of free light chains that are typically crystalline, but can also be noncrystalline structures. PATIENT CONCERNS: A 62-year-old man was hospitalized for the investigation of abnormal urine test results lasting for 1 year and kidney-function abnormalities persisting for more than 1 month. DIAGNOSES: Noncrystalline LCPT and MM. INTERVENTIONS: The patient was treated with the lenalidomide, bortezomib, and dexamethasone and pomalidomide, bortezomib, and dexamethasone chemotherapy regimens. OUTCOMES: Complete remission of MM was achieved, and the patient's renal function returned to normal. LESSONS: This case report highlights the importance of renal pathology in the diagnosis of patients with unexplained chronic kidney disease and proteinuria.

Dual therapeutic targeting of MYC and JUNB transcriptional programs for enhanced anti-myeloma activity.

Deregulation of transcription factors (TFs) leading to uncontrolled proliferation of tumor cells within the microenvironment represents a hallmark of cancer. However, the biological and clinical impact of transcriptional interference, particularly in multiple myeloma (MM) cells, remains poorly understood. The present study shows for the first time that MYC and JUNB, two crucial TFs implicated in MM pathogenesis, orchestrate distinct transcriptional programs. Specifically, our data revealed that expression levels of MYC, JUNB, and their respective downstream targets do not correlate and that their global chromatin-binding patterns are not significantly overlapping. Mechanistically, MYC expression was not affected by JUNB knockdown, and conversely, JUNB expression and transcriptional activity were not affected by MYC knockdown. Moreover, suppression of MYC levels in MM cells via targeting the master regulator BRD4 by either siRNA-mediated knockdown or treatment with the novel proteolysis targeting chimera (PROTAC) MZ-1 overcame bone marrow (BM) stroma cell/IL-6-induced MYC- but not MEK-dependent JUNB-upregulation and transcriptional activity. Consequently, targeting of the two non-overlapping MYC- and JUNB-transcriptoms by MZ-1 in combination with genetic or pharmacological JUNB-targeting approaches synergistically enhanced MM cell death, both in 2D and our novel dynamic 3D models of the BM milieu as well as in murine xenografts. In summary, our data emphasize the opportunity to employ MYC and JUNB dual-targeting treatment strategies in MM as another exciting approach to further improve patient outcomes.

Policy and perspective on outpatient programs for autologous hematopoietic cell transplantation and immune-effector cell therapy administration.

High-dose chemotherapy with autologous hematopoietic cell transplantation (AutoHCT) has long been an integral treatment modality for multiple myeloma and non-Hodgkin lymphoma. Over the past 25 years, numerous institutions have shifted this practice from requiring hospitalization to one that can be performed in an ambulatory setting, resulting in cost savings and improved quality of life for patients. The recent advent immune-effector cell (IEC) therapies and expansion of their indications is changing the treatment landscape for hematologic and non-hematologic malignancies. However, current financial models and reimbursement structures threaten the viability and sustainability of this treatment modality should it continue to require inpatient administration and management. This threat is leading institutions to develop outpatient IEC programs based off the outpatient AutoHCT templates. Integral to the success of both is a cohesive program with outpatient-specific standard operating protocols, highly-trained providers and staff with expertise specific in these treatment modalities, evidenced-based supportive care and prophylaxis plans, extensive caregiver vetting and education, and the infrastructure to support all individuals involved. In this policy and practice review we provide an overview of the guidelines and published academic experiences, give a perspective-based description of the roles and responsibilities of the individuals involved in this process at our institution, and highlight actionable recommendations that could allow for the dissemination and implementation of outpatient AutoHCT and IEC programs more broadly.

Liquid biopsy of peripheral blood using mass spectrometry detects primary extramedullary disease in multiple myeloma patients.

Multiple myeloma (MM) is the second most prevalent hematological malignancy, characterized by infiltration of the bone marrow by malignant plasma cells. Extramedullary disease (EMD) represents a more aggressive condition involving the migration of a subclone of plasma cells to paraskeletal or extraskeletal sites. Liquid biopsies could improve and speed diagnosis, as they can better capture the disease heterogeneity while lowering patients' discomfort due to minimal invasiveness. Recent studies have confirmed alterations in the proteome across various malignancies, suggesting specific changes in protein classes. In this study, we show that MALDI-TOF mass spectrometry fingerprinting of peripheral blood can differentiate between MM and primary EMD patients. We constructed a predictive model using a supervised learning method, partial least squares-discriminant analysis (PLS-DA) and evaluated its generalization performance on a test dataset. The outcome of this analysis is a method that predicts specifically primary EMD with high sensitivity (86.4%), accuracy (78.4%), and specificity (72.4%). Given the simplicity of this approach and its minimally invasive character, this method provides rapid identification of primary EMD and could prove helpful in clinical practice.

Prognostic value of the "dynamic" R2-ISS in patients with multiple myeloma undergoing anti-CD38 antibody-based triplet therapies.

To retrospectively analyze whether the second revision of the international staging system (R2-ISS) influenced prognosis at treatment initiation in patients with multiple myeloma (MM) receiving anti-CD38 antibody-based triplet treatments. High-risk chromosomal abnormalities were examined from diagnosis to treatment initiation and considered positive if detected once. R2-ISS was recalculated at the initiation of treatment and defined as "dynamic R2-ISS." Data from 150 patients who underwent the defined treatments were analyzed. The median progression-free survival (PFS) was 19.5 months, and the median overall survival (OS) was 36.5 months. Dynamic R2-ISS significantly stratified prognoses for both PFS and OS. The median PFS for patients with dynamic R2-ISS IV was 3.3 months, and the median OS was 11.7 months, indicating extremely poor outcomes. Although the Revised International Staging System (R-ISS) calculated at the initiation of treatment significantly stratified treatment outcomes, the patients classified as R-ISS could be further stratified by R2-ISS to provide better prognostic information. Dynamic R2-ISS showed potential as a prognostic tool in patients with MM who are treated with anti-CD38 antibody-based triplet therapies.

Advances and challenges in anti-cancer vaccines for multiple myeloma.

Multiple myeloma (MM) is a hematological cancer marked by plasma cell accumulation in the bone marrow. Despite treatment advancements, MM remains incurable in most patients. MM-associated immune dysregulation fosters disease progression, prompting research into immunotherapy to combat the disease. An area of immunotherapy investigation is the design of myeloma vaccine therapy to reverse tumor-associated immune suppression and elicit tumor-specific immune responses to effectively target MM cells. This article reviews vaccine immunotherapy for MM, categorizing findings by antigen type and delivery method. Antigens include idiotype (Id), tumor-associated (TAA), tumor-specific (TSA), and whole tumor lysate. Myeloma vaccination has so far shown limited clinical efficacy. However, further studies are essential to optimize various aspects, including antigen and patient selection, vaccine timing and sequencing, and rational combinations with emerging MM treatments.

Lys-63-specific deubiquitinase BRCC36 enhances the sensitivity of multiple myeloma cells to lenalidomide by inhibiting lysosomal degradation of cereblon.

Multiple myeloma (MM) is the second most common hematological tumor in adults. Immunomodulatory drugs (IMiDs), such as thalidomide and lenalidomide (Len), are effective drugs for the treatment of multiple myeloma. Len can recruit IKZF1 and IKZF3 to cereblon (CRBN), a substrate receptor of the cullin 4-RING E3 ligase (CRL4), promote their ubiquitination and degradation, and finally inhibit the proliferation of myeloma cells. However, MM patients develop resistance to IMiDs over time, leading to disease recurrence and deterioration. To explore the possible approaches that may enhance the sensitivity of IMiDs to MM, in this study, we used the proximity labeling technique TurboID and quantitative proteomics to identify Lys-63-specific deubiquitinase BRCC36 as a CRBN-interacting protein. Biochemical experiments demonstrated that BRCC36 in the BRISC complex protects CRBN from lysosomal degradation by specifically cleaving the K63-linked polyubiquitin chain on CRBN. Further studies found that a small-molecule compound SHIN1, which binds to BRISC complex subunit SHMT2, can upregulate CRBN by elevating BRCC36. The combination of SHIN1 and Len can further increase the sensitivity of MM cells to IMiDs. Therefore, this study provides the basis for the exploration of a possible strategy for the SHIN1 and Len combination treatment for MM.

Recurrent Cutaneous Manifestation in Multiple Myeloma.

Cutaneous involvement is an uncommonly encountered manifestation in multiple myeloma (MM), more commonly observed in patients with aggressive subtypes, and often resistant to conventional therapies. Due to its infrequency, reported clinical characteristics have been diverse and relatively non-specific. Particularly uncommon is lower extremity involvement. In this case report, we present a unique case of a patient with refractory immunoglobulin G lambda MM, who subsequently developed recurrence in the lower leg, while being on systemic therapy. Initially, the lesion resembled squamous cell carcinoma, posing a diagnostic challenge. Through meticulous histopathological and immunohistochemical evaluation, cutaneous involvement by MM was confirmed. This case highlights the importance of maintaining a high clinical suspicion for cutaneous involvement in patients with MM who present with new skin lesions, as early diagnosis is crucial for appropriate management.

Super enhancer acquisition drives expression of oncogenic PPP1R15B that regulates protein homeostasis in multiple myeloma.

Multiple myeloma is a hematological malignancy arising from immunoglobulin-secreting plasma cells. It remains poorly understood how chromatin rewiring of regulatory elements contributes to tumorigenesis and therapy resistance in myeloma. Here we generate a high-resolution contact map of myeloma-associated super-enhancers by integrating H3K27ac ChIP-seq and HiChIP from myeloma cell lines, patient-derived myeloma cells and normal plasma cells. Our comprehensive transcriptomic and phenomic analyses prioritize candidate genes with biological and clinical implications in myeloma. We show that myeloma cells frequently acquire SE that transcriptionally activate an oncogene PPP1R15B, which encodes a regulatory subunit of the holophosphatase complex that dephosphorylates translation initiation factor eIF2α. Epigenetic silencing or knockdown of PPP1R15B activates pro-apoptotic eIF2α-ATF4-CHOP pathway, while inhibiting protein synthesis and immunoglobulin production. Pharmacological inhibition of PPP1R15B using Raphin1 potentiates the anti-myeloma effect of bortezomib. Our study reveals that myeloma cells are vulnerable to perturbation of PPP1R15B-dependent protein homeostasis, highlighting a promising therapeutic strategy.

Deciphering the genetics and mechanisms of predisposition to multiple myeloma.

Multiple myeloma (MM) is an incurable malignancy of plasma cells. Epidemiological studies indicate a substantial heritable component, but the underlying mechanisms remain unclear. Here, in a genome-wide association study totaling 10,906 cases and 366,221 controls, we identify 35 MM risk loci, 12 of which are novel. Through functional fine-mapping and Mendelian randomization, we uncover two causal mechanisms for inherited MM risk: longer telomeres; and elevated levels of B-cell maturation antigen (BCMA) and interleukin-5 receptor alpha (IL5RA) in plasma. The largest increase in BCMA and IL5RA levels is mediated by the risk variant rs34562254-A at TNFRSF13B. While individuals with loss-of-function variants in TNFRSF13B develop B-cell immunodeficiency, rs34562254-A exerts a gain-of-function effect, increasing MM risk through amplified B-cell responses. Our results represent an analysis of genetic MM predisposition, highlighting causal mechanisms contributing to MM development.

[Cytoplasmic light-chain immunofluorescence combined with FISH in bone marrow smears to detect cytogenetic abnormalities in multiple myeloma].

Objective: To analyze the sensitivity of cytoplasmic light-chain immunofluorescence with fluorescence in situ hybridization in bone marrow smears (new FISH) for detecting cytogenetic abnormalities in multiple myeloma (MM) . Methods: 42 MM patients admitted to the First Affiliated Hospital of Nanjing Medical University from April 2022 to October 2023 were enrolled. The patients with MM were detected by new FISH and CD138 immunomagnetic bead sorting technology combined with FISH (MACS-FISH) or cytoplasmic immunoglobulin FISH (cIg-FISH) to analyze cytogenetic detection results using combination probes which included 1q21/1p32, p53, IgH, IgH/FGFR3 [t (4;14) ], and IgH/MAF [t (14;16) ]. Results: In 23 patients with MM, the abnormality detection rates of cIg-FISH and new FISH were 95.7% and 100.0%, respectively (P>0.05). The detection rates of 1q21+, 1p32-, p53 deletion, and IgH abnormalities by cIg-FISH and new FISH were consistent, which were 52.2%, 8.7%, 17.4%, and 65.2%, respectively. The results of the two methods further performed with t (4;14) and t (14;16) in patients with IgH abnormalities were identical. The positive rate of t (4;14) was 26.7%, whereas t (14;16) was not detected. In 19 patients with MM, the abnormality detection rates of MACS-FISH and new FISH were 73.7% and 63.2%, respectively (P>0.05). The positivity rate of 1q21+, 1p32- and IgH abnormalities detected by MACS-FISH were slightly higher than those detected by new FISH; however, the differences were not statistically significant (all P values >0.05) . Conclusion: The new FISH method has a higher detection rate of cytogenetic abnormalities in patients with MM and has good consistency with MACS-FISH and cIg-FISH.