Proteasome Inhibitors for the Treatment of Multiple Myeloma

Canagliflozin differentially modulates carfilzomib-induced endoplasmic reticulum stress in multiple myeloma and endothelial cells

Carfilzomib (CFZ), a second-generation proteasome inhibitor, is a key treatment for multiple myeloma (MM), but its use is associated with significant cardiovascular adverse events (CVAEs), including heart failure and hypertension. Endothelial dysfunction is believed to contribute to these CVAEs. Building on our previous findings that CFZ induces endothelial toxicity and that canagliflozin protects against CFZ-induced endothelial apoptosis, this study aimed to evaluate CFZ-induced endoplasmic reticulum (ER) stress and autophagy in endothelial and MM cells, as well as the impact of canagliflozin on these processes and its impact on the anticancer effects of CFZ in MM cells. Endothelial cells (HUVECs and EA.hy926) and multiple myeloma cells (RPMI8226) were treated with 0.5 µM CFZ, either alone or in combination with canagliflozin (5-20 µM), to assess the effects on ER stress and autophagy in both cell types. CFZ induced ER stress in endothelial and MM cells. In endothelial cells, canagliflozin mitigated CFZ-induced markers of ER stress, while unexpectedly upregulating CFZ-induced CHOP. Whereas, in MM cells, canagliflozin did not alter CFZ-induced ER stress, but instead further upregulated CFZ-induced ATF-4. In addition, CFZ induced autophagy in endothelial cells while inhibiting it in MM cells. Canagliflozin abrogated CFZ-induced autophagy in endothelial cells. In striking contrast to its effects in endothelial cells, canagliflozin enhanced the cytotoxic effects of CFZ in MM cells. Intriguingly, in an innovative co-culture system, canagliflozin enhanced CFZ-induced apoptosis in MM cells while protecting endothelial cells. These findings underscore the dual role of canagliflozin in reducing CFZ-induced endothelial toxicity, while enhancing its cytotoxic effect in MM.

Efficacy and safety of anti-CD38 monoclonal antibodies-based therapy versus standard therapy in newly diagnosed multiple myeloma patients: a systematic review and meta-analysis

Background

Anti-CD38 monoclonal antibodies (mAbs) have significantly changed the multiple myeloma treatment landscape. This meta-analysis compared the efficacy and safety of anti-CD38 mAb-based therapy versus standard therapy in newly diagnosed multiple myeloma (NDMM) patients.

Methods

We performed a comprehensive literature search on PubMed, the Cochrane Database, and ClinicalTrials.gov. The primary outcomes were progression-free survival (PFS) and minimal residual disease (MRD) status. Dichotomous outcomes were pooled using risk ratio (RR) along with the 95% confidence interval (CI) in RevMan 5.4. Subgroup analysis and meta-regression analysis were performed. The RoB 2.0 tool was used to assess the risk of bias.

Results

Our meta-analysis included 11 randomized controlled trials. There were 5270 patients; 3040 TEs and 2230 TIEs. Anti-CD38 mAbs significantly improved MRD negativity (RR 1.94, 95% CI: 1.59-2.37; p < 0.00001) and PFS (RR 0.51, 95% CI: 0.45-0.58; p < 0.00001). Subgroup analyses revealed better outcomes for both the TE (MRD: RR 1.52, 95% CI: 1.37-1.68; PFS: RR 0.43, 95% CI: 0.34-0.54) and TIE (MRD: RR 3.49, 95% CI: 2.65-4.61; PFS: RR 0.55, 95% CI: 0.47-0.64) populations. Meta-regression revealed that Eastern Cooperative Oncology Group (ECOG) score 0 significantly influenced MRD status (β = -0.015, p < 0.05), whereas ECOG scores 1 and 2 lacked statistical significance. Subgroup analysis revealed that PFS was significantly different between standard (RR 0.47) and high (RR 0.81) cytogenetic risk groups.

Conclusion

In NDMM patients, anti-CD38 mAb-based therapy significantly improved MRD status, and PFS compared with standard therapy alone, in both TE and TIE patients, suggesting a favorable benefit-risk profile.

Design of a molecularly imprinted polymer sensor modified with saffron-based copper nanoflowers for highly selective and sensitive determination of bortezomib

This work represents the first successful application of a molecularly imprinted polymer (MIP)-based electrochemical sensor for the sensitive and selective determination of the first developed proteasome inhibitor, bortezomib (BOR). BOR is used for the treatment of multiple myeloma, gastrointestinal stromal tumors, and mantle cell lymphoma. It shows its desired effect through the boronate group and can be administered intravenously or subcutaneously. The MIP-based electrochemical sensor design includes the integration of green-synthesized saffron-based copper nanoflowers (CuNFs) from Crocus sativus L. to increase the active surface area and porosity of the glassy carbon electrode (GCE) surface. 2-Acrylamido-2-methyl-1-propanesulfonic acid (AMPS) was selected as the functional monomer along with other MIP components. Detailed characterizations of the developed CuNFs/AMPS/MIP-GCE sensor and CuNFs were performed using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray analysis (EDX), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The indirect measurement approach using 5.0 mM [Fe(CN)6]3-/4- solution was used to determine BOR in the linear range of 2.5 × 10-13 M - 2.5 × 10-12 M (0.25-2.5 pM). The LOD and LOQ values of the sensor obtained at the fM level (29 fM and 96.7 fM), which has a linear response in the commercial human serum sample in the same concentration range, emphasize its sensitivity (1.89 × 1013 and 2.14 × 1013 μA/M for standard solution and serum). The repeatability and reproducibility of the sensor were between 0.87 % and 2.17 %, showing its reliability. The successful performance of the sensor in the presence of metabolites belonging to BOR demonstrates its unique selectivity. The selectivity was demonstrated via relative imprinting factor (IF') values (higher than 3.5) against BOR's metabolites. The stability of the CuNFs/AMPS/MIP-GCE sensor was found to be 5 days.

Ketorolac disturbs proteasome functions and induces mitochondrial abnormality-associated apoptosis

Non-steroidal anti-inflammatory drugs (NSAIDs) are recommended to treat moderate-to-severe pain. Previous studies suggest that NSAIDs can suppress cellular proliferation and elevate apoptosis in different cancer cells. Ketorolac is an NSAID and can reduce the cancer cells' viability. However, molecular mechanisms by which Ketorolac can induce apoptosis and be helpful as an anti-tumor agent against carcinogenesis are unclear. Here, we observed treatment with Ketorolac disturbs proteasome functions, which induces aggregation of aberrant ubiquitinated proteins. Ketorolac exposure also induced the aggregation of expanded polyglutamine proteins, results cellular proteostasis disturbance. We found that the treatment of Ketorolac aggravates the accumulation of various cell cycle-linked proteins, which results in pro-apoptotic induction in cells. Ketorolac-mediated proteasome disturbance leads to mitochondrial abnormalities. Finally, we have observed that Ketorolac treatment depolarized mitochondrial membrane potential, released cytochrome c into cytoplasm, and induced apoptosis in cells, which could be due to proteasome functional depletion. Perhaps more in-depth research is required to understand the details of NSAID-based anti-proliferative molecular mechanisms that can elevate apoptosis in cancer cells and generate anti-tumor potential with the combination of putative cancer drugs.

Disrupting USP39 deubiquitinase function impairs the survival and migration of multiple myeloma cells through ZEB1 degradation

BACKGROUND

Multiple Myeloma (MM) is the second most common hematological malignancy, characterized by the accumulation of monoclonal plasmocytes in the bone marrow. Despite advancements with proteasome inhibitors, immunomodulatory agents, and CD38-targeting antibodies, MM remains largely incurable due to resistant clones and frequent relapses. The success of the proteasome inhibitor bortezomib (BTZ) in MM treatment highlights the critical role of the ubiquitin-proteasome system (UPS) in this disease. Deubiquitinases (DUBs), which regulate protein stability, interactions, and localization by removing ubiquitin modifications, have emerged as promising therapeutic targets in various cancers, including MM.

METHODS

Through a comprehensive loss-of-function screen, we identified USP39 as a critical survival factor for MM cells. Gene Set Enrichment Analysis (GSEA) was employed to correlate USP39 mRNA levels with clinical outcomes in MM patients. USP39 protein expression was evaluated via immunohistochemistry (IHC) on bone marrow samples from MM patients and healthy controls. The impact of USP39 knockdown via SiRNA was assessed through in vitro assays measuring cellular metabolism, clonogenic capacity, cell cycle progression, apoptosis, and sensitivity to BTZ. Co-immunoprecipitation and deubiquitination assays were conducted to elucidate the interaction and regulation of ZEB1 by USP39. Finally, in vitro and in vivo zebrafish experiments were used to characterize the biological consequences of ZEB1 regulation by USP39.

RESULTS

Our study found that elevated USP39 mRNA levels are directly associated with shorter survival in MM patients. USP39 protein expression is significantly higher in MM patient plasmocytes compared to healthy individuals. USP39 knockdown inhibits clonogenic capacity, induces cell cycle arrest, triggers apoptosis, and overcomes BTZ resistance. Gain-of-function assays revealed that USP39 stabilizes the transcription factor ZEB1, enhancing the proliferation and the trans-migratory potential of MM cells.

CONCLUSIONS

Our findings highlight the critical role of the deubiquitinase USP39, suggesting that the USP39/ZEB1 axis could serve as a potential diagnostic marker and therapeutic target in MM.

Antisense oligonucleotides-based approaches for the treatment of multiple myeloma

Multiple myeloma (MM), a hematological malignancy which affects the monoclonal plasma cells in the bone marrow, is in rising incidence around the world, accounting for approximately 2 % of newly diagnosed cancer cases in the US, Australia, and Western Europe. Despite the progress made in the last few years in the available therapeutic options (e.g. proteasome inhibitors, immunomodulatory drugs, tumor cell-targeting monoclonal antibodies, autologous stem cell transplantation, etc.), multiple myeloma is still regarded as incurable, and the prognosis for most patients is poor, as the disease becomes refractory to treatment throughout time. Antisense oligonucleotides (ASOs), designed to be complementary to selected messenger RNA (mRNA) sequences of specific genes involved in the pathogenesis of multiple myeloma (e.g. Bcl-2, Mcl-1, STAT3, IRF4, IL6, ILF2, HK2, c-MYC, etc.), represent a promising alternative to conventional treatments, and can be tailored according to the individual requirements of each patient. The main goal of antisense therapy for multiple myeloma consists in silencing the specific genes participating in the proliferation and survival of tumor cells via RNA cleavage or RNA blockage, thus preventing mRNA interactions with ribosomes and altering the process of protein translation. So far, pre-clinical and clinical studies showed promising results when Bcl-2 (Genasense), Mcl-1 (ISIS2048), STAT3 (ISIS345794) and IRF4 (ION251) were targeted using ASOs-based formulations. However, FDA approval has not been obtained yet for these products, mainly due to ethical and financial issues posed by customized therapies and insufficient information regarding their long-term toxicity. This review aims to provide a comprehensive insight into antisense oligonucleotides-based therapies, their potential chemical modifications, the mechanisms involved in ASOs-mediated gene silencing, potential systems for ASOs delivery, and the applications of ASOs in the treatment of multiple myeloma. The relevant genetic targets in ASOs-based MM therapies were described, and the research results obtained in the studies conducted so far were analyzed, with a focus on the ASOs formulations that were already included in clinical trials. In the end, current challenges, and future perspectives of antisense therapy for MM were also discussed.

Recent advances in targeted drug delivery systems for multiple myeloma

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

Characterization of driver mutations identifies gene signatures predictive of prognosis and treatment sensitivity in multiple myeloma

In multiple myeloma (MM), while frequent mutations in driver genes are crucial for disease progression, they traditionally offer limited insights into patient prognosis. This study aims to enhance prognostic understanding in MM by analyzing pathway dysregulations in key cancer driver genes, thereby identifying actionable gene signatures. We conducted a detailed quantification of mutations and pathway dysregulations in 10 frequently mutated cancer driver genes in MM to characterize their comprehensive mutational impacts on the whole transcriptome. This was followed by a systematic survival analysis to identify significant gene signatures with enhanced prognostic value. Our systematic analysis highlighted 2 significant signatures, TP53 and LRP1B, which notably outperformed mere mutation status in prognostic predictions. These gene signatures remained prognostically valuable even when accounting for clinical factors, including cytogenetic abnormalities, the International Staging System (ISS), and its revised version (R-ISS). The LRP1B signature effectively distinguished high-risk patients within low/intermediate-risk categories and correlated with significant changes in the tumor immune microenvironment. Additionally, the LRP1B signature showed a strong association with proteasome inhibitor pathways, notably predicting patient responses to bortezomib and the progression from monoclonal gammopathy of unknown significance to MM. Through a rigorous analysis, this study underscores the potential of specific gene signatures in revolutionizing the prognostic landscape of MM, providing novel clinical insights that could influence future translational oncology research.

The emerging role of melflufen and peptide-conjugates in multiple myeloma

PURPOSE OF REVIEW

The past two decades have witnessed an impressive expansion in the treatment landscape of multiple myeloma, leading to significant improvements in progression-free; as well as overall survival. However, almost all patients still experience multiple relapses during their disease course, with biological and cytogenetic heterogeneity affecting response to subsequent treatments. The purpose of this review is to provide a historical background regarding the role of alkylating agents and an updated data regarding the use of peptide-drug conjugates such as melflufen for patients with multiple myeloma.

RECENT FINDINGS

The combination of daratumumab-melflufen-dexamethasone evaluated in the LIGHTHOUSE study showed a statistically significant improvement in progression-free survival compared to single-agent daratumumab (not reached vs. 4.9 months respectively; P  = 0.0032), with improvement in overall response rate to 59% vs. 30% respectively; P  = 0.03.

SUMMARY

There have been an interest in developing and utilizing peptide-drug conjugates such as melflufen for treatment of patients with multiple myeloma, especially in the relapsed setting given historical results with alkylating agents, the use of which has been limited by dose-related toxicities in a disease that remains largely incurable. Single agent melflufen initially showed promising results especially in specific subgroups of heavily pretreated patients before the decision to suspend all clinical trials evaluating this agent after results from the OCEAN phase 3 trial. Subsequent reported analyses especially for melflufen-based combinations appear promising and suggest a potential use of peptide-drug conjugates provided optimal patient selection, as well as identification of the best companion agent.

Structural elucidation of recombinant Trichomonas vaginalis 20S proteasome bound to covalent inhibitors

The proteasome is a proteolytic enzyme complex essential for protein homeostasis in mammalian cells and protozoan parasites like Trichomonas vaginalis (Tv), the cause of the most common, non-viral sexually transmitted disease. Tv and other protozoan 20S proteasomes have been validated as druggable targets for antimicrobials. However, low yields and purity of the native proteasome have hindered studies of the Tv 20S proteasome (Tv20S). We address this challenge by creating a recombinant protozoan proteasome by expressing all seven α and seven β subunits of Tv20S alongside the Ump-1 chaperone in insect cells. The recombinant Tv20S displays biochemical equivalence to its native counterpart, confirmed by various assays. Notably, the marizomib (MZB) inhibits all catalytic subunits of Tv20S, while the peptide inhibitor carmaphycin-17 (CP-17) specifically targets β2 and β5. Cryo-electron microscopy (cryo-EM) unveils the structures of Tv20S bound to MZB and CP-17 at 2.8 Å. These findings explain MZB's low specificity for Tv20S compared to the human proteasome and demonstrate CP-17's higher specificity. Overall, these data provide a structure-based strategy for the development of specific Tv20S inhibitors to treat trichomoniasis.

Lymphocytes in autoimmune encephalitis: Pathogenesis and therapeutic target

Autoimmune encephalitis (AE) is an inflammatory disease of the central nervous system characterized by the production of various autoimmune antibodies targeting neuronal proteins. The pathogenesis of AE remains elusive. Accumulating evidence suggests that lymphocytes, particularly B and T lymphocytes, play an integral role in the development of AE. In the last two decades, autoimmune neural antibodies have taken center stage in diagnosing AE. Recently, increasing evidence has highlighted the importance of T lymphocytes in the onset of AE. CD4+ T cells are thought to influence disease progression by secreting associated cytokines, whereas CD8+ T cells exert a cytotoxic role, causing irreversible damage to neurons mainly in patients with paraneoplastic AE. Conventionally, the first-line treatments for AE include intravenous steroids, intravenous immunoglobulin, and plasma exchange to remove pathogenic autoantibodies. However, a minority of patients are insensitive to conventional first-line treatment protocols and suffer from disease relapse, a condition referred to as refractory AE. In recent years, new treatments, such as rituximab or CAAR-T, which target pathogenic lymphocytes in patients with AE, have offered new therapeutic options for refractory AE. This review aims to describe the current knowledge about the function of B and T lymphocytes in the pathophysiology of AE and to summarize and update the immunotherapy options for treating this disease.

Multiple myeloma and infections in the era of novel treatment modalities

Infections are major cause of morbidity and mortality in patients with multiple myeloma. Current treatment landscape of newly-diagnosed multiple myeloma includes different classes of drugs, such as proteasome inhibitors, immunomodulatory drugs, and monoclonal antibodies, all of which are characterized by specific risk and pattern of infectious complications. Additionally, autologous and allogeneic hematopoietic cell transplantation, widely used in the treatment of multiple myeloma, are complex procedures, carrying a significant risk of complications, and mainly infections. Finally, novel treatment modalities such as bispecific T-cell engagers and chimeric antigen receptor T-lymphocytes have been changing the paradigm of myeloma treatment in relapsed-refractory setting. These agents due to unique mechanism of action carry distinct pattern of infectious complications. In this review, an attempt has been made to summarize the incidence, risk factors, and patterns of infections during different stages of myeloma treatment including novel treatment modalities, and to provide evidence underlying the current concept of infectious disease prophylaxis in this category of patients.

In silico identification of 20S proteasome-β5 subunit inhibitors using structure-based virtual screening

Proteasome inhibitors have effective anti-tumor activity in cell culture and can induce apoptosis by interfering with the degradation of cell cycle proteins. 20S Proteasome is acknowledged to be a satisfactory target that has persistent properties against the human immune defense and is obligatory for the degradation of some vital proteins. This study aimed to identify potential inhibitors against 20S proteasome, specifically the β5 subunit, using structure-based virtual screening and molecular docking to reduce the number of ligands that should be eligible for experimental assays. A total of 4961 molecules with anticancer activity were screened from the ASINEX database. The filtered compounds that showed higher docking affinity were then used in more sophisticated molecular docking simulations with AutoDock Vina for validation. Finally, six drug molecules (BDE 28974746, BDE 25657353, BDE 29746159, BDD 27844484, BDE 29746109, and BDE 29746162) exhibited highly significant interactions compared to the positive controls were retained. Among these six molecules, three molecules (BDE 28974746, BDE 25657353, and BDD 27844484) showed high binding affinity and binding energy compared with Carfilzomib and Bortezomib. Molecular simulation and dynamics studies of the top three drug molecules in each case allowed us to draw further conclusions about their stability with the β5 subunit. Computed absorption, distribution, metabolism, excretion and toxicity studies on these derivatives showed encouraging results with very low toxicity, distribution, and absorption. These compounds may serve as potential hits for further biological evaluation in the development of new proteasome inhibitors.Communicated by Ramaswamy H. Sarma.

A comprehensive review of the PTEN/PI3K/Akt axis in multiple myeloma: From molecular interactions to potential therapeutic targets

Phosphatase and tensin homolog (PTEN), phosphatidylinositol 3-kinase (PI3K), and protein kinase B (Akt) signaling pathways contribute to the development of several cancers, including multiple myeloma (MM). PTEN is a tumor suppressor that influences the PI3K/Akt/mTOR pathway, which in turn impacts vital cellular processes like growth, survival, and treatment resistance. The current study aims to present the role of PTEN and PI3K/Akt/mTOR signaling in the development of MM and its response to treatment. In addition, the molecular interactions in MM that underpin the PI3K/Akt/mTOR pathway and address potential implications for the development of successful treatment plans are also discussed in detail. We investigate their relationship to both upstream and downstream regulators, highlighting new developments in combined therapies that target the PTEN/PI3K/Akt axis to overcome drug resistance, including the use of PI3K and mitogen-activated protein kinase (MAPK) inhibitors. We also emphasize that PTEN/PI3K/Akt pathway elements may be used in MM diagnosis, prognosis, and therapeutic targets.

Bortezomib promotes the TRAIL-mediated killing of resistant rhabdomyosarcoma by ErbB2/Her2-targeted CAR-NK-92 cells via DR5 upregulation

Treatment resistance and immune escape are hallmarks of metastatic rhabdomyosarcoma (RMS), underscoring the urgent medical need for therapeutic agents against this disease entity as a key challenge in pediatric oncology. Chimeric antigen receptor (CAR)-based immunotherapies, such as the ErbB2 (Her2)-CAR-engineered natural killer (NK) cell line NK-92/5.28.z, provide antitumor cytotoxicity primarily through CAR-mediated cytotoxic granule release and thereafter-even in cases with low surface antigen expression or tumor escape-by triggering intrinsic NK cell-mediated apoptosis induction via additional ligand/receptors. In this study, we showed that bortezomib increased susceptibility toward apoptosis in clinically relevant RMS cell lines RH30 and RH41, and patient-derived RMS tumor organoid RMS335, by upregulation of the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor DR5 in these metastatic, relapsed/refractory (r/r) RMS tumors. Subsequent administration of NK-92/5.28.z cells significantly enhanced antitumor activity in vitro. Applying recombinant TRAIL instead of NK-92/5.28.z cells confirmed that the synergistic antitumor effects of the combination treatment were mediated via TRAIL. Western blot analyses indicated that the combination treatment with bortezomib and NK-92/5.28.z cells increased apoptosis by interacting with the nuclear factor κB, JNK, and caspase pathways. Overall, bortezomib pretreatment can sensitize r/r RMS tumors to CAR- and, by upregulating DR5, TRAIL-mediated cytotoxicity of NK-92/5.28.z cells.

Progression of monoclonal gammopathy of undetermined significance to multiple myeloma is associated with enhanced translational quality control and overall loss of surface antigens

BACKGROUND

Despite significant advancements in treatment strategies, multiple myeloma remains incurable. Additionally, there is a distinct lack of reliable biomarkers that can guide initial treatment decisions and help determine suitable replacement or adjuvant therapies when relapse ensues due to acquired drug resistance.

METHODS

To define specific proteins and pathways involved in the progression of monoclonal gammopathy of undetermined significance (MGUS) to multiple myeloma (MM), we have applied super-SILAC quantitative proteomic analysis to CD138 + plasma cells from 9 individuals with MGUS and 37 with MM.

RESULTS

Unsupervised hierarchical clustering defined three groups: MGUS, MM, and MM with an MGUS-like proteome profile (ML) that may represent a group that has recently transformed to MM. Statistical analysis identified 866 differentially expressed proteins between MM and MGUS, and 189 between MM and ML, 177 of which were common between MGUS and ML. Progression from MGUS to MM is accompanied by upregulated EIF2 signaling, DNA repair, and proteins involved in translational quality control, whereas integrin- and actin cytoskeletal signaling and cell surface markers are downregulated.

CONCLUSION

Compared to the premalignant plasma cells in MGUS, malignant MM cells apparently have mobilized several pathways that collectively contribute to ensure translational fidelity and to avoid proteotoxic stress, especially in the ER. The overall reduced expression of immunoglobulins and surface antigens contribute to this and may additionally mediate evasion from recognition by the immune apparatus. Our analyses identified a range of novel biomarkers with potential prognostic and therapeutic value, which will undergo further evaluation to determine their clinical significance.

The numerous facets of 1q21+ in multiple myeloma: Pathogenesis, clinicopathological features, prognosis and clinical progress (Review)

Multiple myeloma (MM) is a malignant neoplasm characterized by the clonal proliferation of abnormal plasma cells (PCs) in the bone marrow and recurrent cytogenetic abnormalities. The incidence of MM worldwide is on the rise. 1q21+ has been found in ~30-40% of newly diagnosed MM (NDMM) patients.1q21+ is associated with the pathophysiological mechanisms of disease progression and drug resistance in MM. In the present review, the pathogenesis and clinicopathological features of MM patients with 1q21+ were studied, the key data of 1q21+ on the prognosis of MM patients were summarized, and the clinical treatment significance of MM patients with 1q21+ was clarified, in order to provide reference for clinicians to develop treatment strategies targeting 1q21+.

Empagliflozin Alleviates Carfilzomib-Induced Cardiotoxicity in Mice by Modulating Oxidative Stress, Inflammatory Response, Endoplasmic Reticulum Stress, and Autophagy

Carfilzomib is an irreversible proteasome inhibitor used for multiple myeloma patients. However, carfilzomib treatment is associated with cardiovascular complications. Empagliflozin, an Sodium Glucose Co-transporter 2 inhibitor (SGLT-2) inhibitor, is an oral antidiabetic drug with proven antioxidant and anti-inflammatory properties. The aim of the present study was to determine the cardioprotective effects of empagliflozin against carfilzomib-induced cardiotoxicity. C57BL/6 mice were randomly divided into four groups: control, empagliflozin, carfilzomib, and carfilzomib + empagliflozin. Empagliflozin prevented carfilzomib-induced cardiotoxicity by ameliorating histological alterations, CK-MB, and troponin-I. Moreover, it inhibited carfilzomib-induced oxidative damage and inflammation via its action on catalase activity, reduced glutathione levels and superoxide dismutase activity, and reduced nuclear factor-κB (p65) and cytokine levels. Mechanistically, empagliflozin abrogated endoplasmic reticulum stress induced by carfilzomib, as evidenced by the effect on the Glucose Regulated Protein-78 (GRP-78)/Activating Transcription Factor 6 (ATF6)/C/EBP homologous protein (CHOP) axis. Intriguingly, carfilzomib significantly induced autophagy, an effect that was further enhanced by empagliflozin, evidenced by increased LC3B and beclin-1 mRNA expression and reduced p62 expression. The effect of empagliflozin on apoptosis was confirmed by reduced expression of active caspase-3. Importantly, empagliflozin did not alter the cytotoxic effect of carfilzomib on human U266B1 multiple myeloma cells. our findings suggest that empagliflozin may provide a new therapeutic strategy to mitigate carfilzomib-induced cardiotoxicity in multiple myeloma patients.

The Relative Efficacy of Available Proteasome Inhibitors in Preventing Muscle Contractures Following Neonatal Brachial Plexus Injury

BACKGROUND

Contractures following neonatal brachial plexus injury (NBPI) are associated with growth deficits in denervated muscles. This impairment is mediated by an increase in muscle protein degradation, as contractures can be prevented in an NBPI mouse model with bortezomib (BTZ), a proteasome inhibitor (PI). However, BTZ treatment causes substantial toxicity (0% to 80% mortality). The current study tested the hypothesis that newer-generation PIs can prevent contractures with less severe toxicity than BTZ.

METHODS

Unilateral brachial plexus injuries were surgically created in postnatal (5-day-old) mice. Following NBPI, mice were treated with either saline solution or various doses of 1 of 3 different PIs: ixazomib (IXZ), carfilzomib (CFZ), or marizomib (MRZ). Four weeks post-NBPI, mice were assessed for bilateral passive range of motion at the shoulder and elbow joints, with blinding to the treatment group, through an established digital photography technique to determine contracture severity. Drug toxicity was assessed with survival curves.

RESULTS

All PIs prevented contractures at both the elbow and shoulder (p < 0.05 versus saline solution controls), with the exception of IXZ, which did not prevent shoulder contractures. However, their efficacies and toxicity profiles differed. At lower doses, CFZ was limited by toxicity (30% to 40% mortality), whereas MRZ was limited by efficacy. At higher doses, CFZ was limited by loss of efficacy, MRZ was limited by toxicity (50% to 60% mortality), and IXZ was limited by toxicity (80% to 100% mortality) and loss of efficacy. Comparisons of the data on these drugs as well as data on BTZ generated in prior studies revealed BTZ to be optimal for preventing contractures, although it, too, was limited by toxicity.

CONCLUSIONS

All of the tested second-generation PIs were able to reduce NBPI-induced contractures, offering further proof of concept for a regulatory role of the proteasome in contracture formation. However, the narrow dose ranges of efficacy for all PIs highlight the necessity of precise proteasome regulation for preventing contractures. Finally, the substantial toxicity stemming from proteasome inhibition underscores the importance of identifying muscle-targeted strategies to suppress protein degradation and prevent contractures safely.

CLINICAL RELEVANCE

Although PIs offer unique opportunities to establish critical mechanistic insights into contracture pathophysiology, their clinical use is contraindicated in patients with NPBI at this time.

The Efficacy of Carfilzomib Treatment in Bortezomib-Refractory Patients-Real Life Experience in a Tertiary Romanian Hospital

Background: Proteasome inhibitors (PIs) represent one of the most effective classes of therapy for patients with multiple myeloma (MM) and are incorporated in many of the current treatment regimens. The first-generation PI, bortezomib, has shown impressive results in patients with either newly diagnosed or relapsed/refractory MM, but once patients become resistant, treatment is increasingly challenging. Although the existing data show that the second-generation PI, carfilzomib, is highly efficient, there is still limited knowledge regarding the response to carfilzomib-based therapy in bortezomib-resistant patients. The aim of this study was to evaluate carfilzomib treatment performance in bortezomib-sensitive versus -refractory patients, in a real-life eastern European country setting. Methods: We retrospectively evaluated 127 adult patients exposed to bortezomib with relapsed or refractory MM, that subsequently received a carfilzomib-based therapy. We investigated the differences in the overall response rate (ORR), progression-free survival (PFS), and overall survival (OS) after carfilzomib-based therapy between the two patient groups. Results: The ORR in the bortezomib-sensitive group was significantly higher than that in the refractory group, leading to a superior PFS in this category of patients. For patients presenting with a high cytogenetic risk, we observed a significant difference in PFS between the bortezomib-sensitive and -refractory group, while standard cytogenetic risk patients presented a similar PFS regardless of the bortezomib sensitivity status. In addition, in patients with ISS (International Staging System) stage I or II, the previous sensitivity to bortezomib correlated with an improved PFS, while for patients with ISS stage III, both groups had a comparable PFS. No significant differences in OS were observed between the two groups. Conclusions: In countries where novel or experimental therapies are not readily available, carfilzomib-based therapy can still be a viable therapy option for patients presenting with bortezomib-refractory status, an ISS stage III, and standard cytogenetic risk.

Synergistic Effect of a Combination of Proteasome and Ribonucleotide Reductase Inhibitors in a Biochemical Model of the Yeast Saccharomyces cerevisiae and a Glioblastoma Cell Line

Proteasome inhibitors are used in the therapy of several cancers, and clinical trials are underway for their use in the treatment of glioblastoma (GBM). However, GBM becomes resistant to chemotherapy relatively rapidly. Recently, the overexpression of ribonucleotide reductase (RNR) genes was found to mediate therapy resistance in GBM. The use of combinations of chemotherapeutic agents is considered a promising direction in cancer therapy. The present work aimed to evaluate the efficacy of the combination of proteasome and RNR inhibitors in yeast and GBM cell models. We have shown that impaired proteasome function results in increased levels of RNR subunits and increased enzyme activity in yeast. Co-administration of the proteasome inhibitor bortezomib and the RNR inhibitor hydroxyurea was found to significantly reduce the growth rate of S. cerevisiae yeast. Accordingly, the combination of bortezomib and another RNR inhibitor gemcitabine reduced the survival of DBTRG-05MG compared to the HEK293 cell line. Thus, yeast can be used as a simple model to evaluate the efficacy of combinations of proteasome and RNR inhibitors.

An alternative fully human anti-BCMA CAR-T shows response for relapsed or refractory multiple myeloma with anti-BCMA CAR-T exposures previously

Chimeric antigen receptor T (CAR-T) cells therapy has made remarkable progress in relapsed/refractory multiple myeloma (R/R MM) treatment. Unfortunately, patients still eventually experience disease progression or relapse even after receiving anti-BCMA CAR-T therapy. At present, there are limited data on available treatment options for patients who have progressed on anti-BCMA CAR-T therapy. In this study, we evaluated the safety and efficacy of fully human anti-BCMA CAR-T (HRC0202) in seven R/R MM patients who were previously exposed to anti-BCMA CAR-T therapy. Three patients received 6.0 × 106 CAR+T cells/kg, one patient received 10.0 × 106 CAR+T cells/kg and three patients received 15.0 × 106 CAR+T cells/kg. Cytokine release syndrome (CRS) of grades 1-2 occurred in three patients (42.9%) and grade ≥3 in two patients (28.6%). Immune effector cell-associated neurotoxic syndrome (ICANS) was not observed in any of the patients. The best overall response rate (ORR) was 71.4% (5/7), with a stringent complete response/complete response (sCR/CR) achieved in three patients. The median progression-free survival (PFS) was 269 days, and median overall survival (OS) for all patients was not reached. The median peak concentration (Cmax) of HRC0202 was 30117.70 (range, 6084.35-147415.10) copies/μg DNA. This study indicated that fully human anti-BCMA CAR-T (HRC0202) is a promising treatment for R/R MM patients who relapsed or refractory from prior anti-BCMA CAR-T infusion.

Cyclophosphamide, Bortezomib, and Dexamethasone and Severe Systolic Heart Failure: A Case Report

Multiple myeloma (MM) is a neoplastic proliferation of plasma cells in bone marrow. Pharmacotherapy for the management of patients with MM includes drug classes like proteasome inhibitors, monoclonal antibodies, immunomodulators, alkylating agents, steroids, etc. We present a case of new-onset heart failure with reduced ejection fraction (HFrEF) in a patient with previously normal ejection fraction after treatment with a cyclophosphamide, bortezomib, and dexamethasone (CyBorD) chemotherapeutic regimen. An echocardiogram done after the completion of nine cycles of chemotherapy in a period of about 4.5 months showed severely decreased left ventricular systolic function with an ejection fraction of only 15-20% and grade I diastolic dysfunction. Cardiac catheterization showed no angiographic evidence of vessel occlusion or epicardial disease. HFrEF was managed with the initiation of guideline-directed medical therapy with cardiology clinic follow-up, and the patient was discharged with a plan to start a lenalidomide-based chemotherapeutic regimen with oncology clinic follow-up. It is, therefore, imperative to perform a thorough cardiovascular assessment before initiation of chemotherapy, complemented by periodic and recurrent assessments of cardiovascular function during and after completion of the treatment course, for early detection and prevention of potentially severe cardiovascular toxicities in patients with MM.

Role of the ubiquitin-proteasome system on macrophages in the tumor microenvironment

Tumor-associated macrophages (TAMs) are key components of the tumor microenvironment, and their different polarization states play multiple roles in tumors by secreting cytokines, chemokines, and so on, which are closely related to tumor development. In addition, the enrichment of TAMs is often associated with poor prognosis of tumors. Thus, targeting TAMs is a potential tumor treatment strategy, in which therapeutic approaches such as reducing TAMs numbers, remodeling TAMs phenotypes, and altering their functions are being extensively investigated. Meanwhile, the ubiquitin-proteasome system (UPS), an important mechanism of protein hydrolysis in eukaryotic cells, participates in cellular processes by regulating the activity and stability of key proteins. Interestingly, UPS plays a dual role in the process of tumor development, and its role in TAMs deserve to be investigated in depth. This review builds on this foundation to further explore the multiple roles of UPS on TAMs and identifies a promising approach to treat tumors by targeting TAMs with UPS.

Organelle stress and alterations in interorganelle crosstalk during liver fibrosis

The synchronous functioning and quality control of organelles ensure cell survival and function and are essential for maintaining homeostasis. Prolonged exposure to stressors (viruses, bacteria, parasitic infections, alcohol, drugs) or genetic mutations often disrupt the functional integrity of organelles which plays a critical role in the initiation and progression of several diseases including chronic liver diseases. One of the most important pathologic consequences of chronic liver diseases is liver fibrosis, characterized by tissue scarring due to the progressive accumulation of extracellular matrix components. Left untreated, fibrosis may advance to life-threatening complications such as cirrhosis, hepatic decompensation, and HCC, which collectively accounts for ∼1 million deaths per year worldwide. Owing to the lack of treatment options that can regress or reverse cirrhosis, liver transplantation is currently the only available treatment for end-stage liver disease. However, the limited supply of usable donor organs, adverse effects of lifelong immunosuppressive regimes, and financial considerations pose major challenges and limit its application. Hence, effective therapeutic strategies are urgently needed. An improved understanding of the organelle-level regulation of fibrosis can help devise effective antifibrotic therapies focused on reducing organelle stress, limiting organelle damage, improving interorganelle crosstalk, and restoring organelle homeostasis; and could be a potential clinical option to avoid transplantation. This review provides a timely update on the recent findings and mechanisms covering organelle-specific dysfunctions in liver fibrosis, highlights how correction of organelle functions opens new treatment avenues and discusses the potential challenges to clinical application.

A matching-adjusted indirect comparison of the efficacy of elranatamab versus physician's choice of treatment in patients with triple-class exposed/refractory multiple myeloma

INTRODUCTION

For patients with triple-class exposed/refractory multiple myeloma (TCE/R MM), prognosis is poor and effective treatment options are limited. Elranatamab is a novel B-cell maturation antigen (BCMA)- and CD3-directed bispecific antibody which was approved by the US Food and Drug Administration in August 2023 and demonstrated safety and efficacy in patients with TCE/R MM in the phase 2, single-arm MagnetisMM-3 trial (NCT04649359). To compare the effectiveness of elranatamab vs physician's choice of treatment (PCT) in the absence of head-to-head comparative data, a matching-adjusted indirect comparison (MAIC) was conducted.

METHODS

Individual patient data from MagnetisMM-3 (Cohort A [BCMA-naïve] N = 123, 14.7 months of follow-up) were reweighted to match published summary data from two real-world studies of PCT in patients with TCE/R MM (LocoMMotion and MAMMOTH) using a propensity score-type logistic regression. Unanchored MAIC analyses were conducted according to National Institute for Health and Care Excellence (NICE) Decision Support Unit (DSU) 18 guidance.

RESULTS

Compared with PCT in LocoMMotion, elranatamab was associated with a significantly higher objective response rate (ORR rate difference: 37.52; 95% CI 26.20-48.83; odds ratio: 4.85; 95% CI 2.85-8.23) and complete or stringent complete response rate (≥CR rate difference: 42.29; 95% CI 31.84-52.74; odds ratio: 184.01; 95% CI 24.66-1372.86), longer progression-free survival (PFS HR 0.32; 95% CI 0.20-0.49), and overall survival (OS HR 0.62; 95% CI 0.40-0.94). Compared with PCT in MAMMOTH, elranatamab was associated with significantly higher ORR (rate difference: 28.14; 95% CI 16.77-39.52; odds ratio: 3.24; 95% CI 1.98-5.32) and ≥ CR (rate difference: 26.22; 95% CI 16.40-36.05; odds ratio: 5.48; 95% CI 2.88-10.44), as well as longer PFS (HR 0.25; 95% CI 0.17-0.37) and OS (HR 0.49; 95% CI 0.33-0.71). Sensitivity analysis results were consistent with the base case.

CONCLUSION

In the MAIC, elranatamab was consistently associated with improved rates and depth of response and significantly longer PFS and OS versus PCT in LocoMMotion and MAMMOTH.

CRIP1 involves the pathogenesis of multiple myeloma via dual-regulation of proteasome and autophagy

BACKGROUND

Multiple myeloma (MM) is an incurable hematological malignancy of the plasma cells. The maintenance of protein homeostasis is critical for MM cell survival. Elevated levels of paraproteins in MM cells are cleared by proteasomes or lysosomes, which are independent but inter-connected with each other. Proteasome inhibitors (PIs) work as a backbone agent and successfully improved the outcome of patients; however, the increasing activity of autophagy suppresses the sensitivity to PIs treatment.

METHODS

The transcription levels of CRIP1 were explored in plasma cells obtained from healthy donors, patients with newly diagnosed multiple myeloma (NDMM), and relapsed/refractory multiple myeloma (RRMM) using Gene expression omnibus datasets. Doxycycline-inducible CRIP1-shRNA and CRIP1 overexpressed MM cell lines were constructed to explore the role of CRIP1 in MM pathogenesis. Proliferation, invasion, migration, proteasome activity and autophagy were examined in MM cells with different CRIP1 levels. Co-immunoprecipitation (Co-IP) with Tandem affinity purification/Mass spectrum (TAP/MS) was performed to identify the binding proteins of CRIP1. The mouse xenograft model was used to determine the role of CRIP1 in the proliferation and drug-resistance of MM cells.

FINDINGS

High CRIP1 expression was associated with unfavorable clinical outcomes in patients with MM and served as a biomarker for RRMM with shorter overall survival. In vitro and in vivo studies showed that CRIP1 plays a critical role in protein homeostasis via the dual regulation of the activities of proteasome and autophagy in MM cells. A combined analysis of RNA-seq, Co-IP and TAP/MS demonstrated that CRIP1 promotes proteasome inhibitors resistance in MM cells by simultaneously binding to de-ubiquitinase USP7 and proteasome coactivator PA200. CRIP1 promoted proteasome activity and autophagosome maturation by facilitating the dequbiquitination and stabilization of PA200.

INTERPRETATION

Our findings clarified the pivotal roles of the CRIP1/USP7/PA200 complex in ubiquitin-dependent proteasome degradation and autophagy maturation involved in the pathogenesis of MM.

FUNDING

A full list of funding sources can be found in the acknowledgements section.

From Multiple Myeloma to Acute Myeloid Leukemia: A Case Report of a 61-year-old Woman after 8 Years of Chemotherapy and Immunotherapy

BACKGROUND

As the second most prevalent hematologic malignancy, multiple myeloma (MM) affects plasma cells and is characterized by chromosomal abnormalities, particularly involving the immunoglobulin heavy chain switch region. MM represents a biologically and clinically heterogeneous hematological malignancy that serves as a clonal evolution model, exhibiting clonal heterogeneity throughout all stages from monoclonal gammopathy undetermined significance (MGUS) and smoldering multiple myeloma (SMM) to MM. Although significant progress has been made in the treatment of MM, leading to improved patient outcomes, concerns are arising regarding disease relapse due to the presence and selection of pre-existing resistant clones or selective pressure during therapy.

CASE PRESENTATION

We present a case of multiple myeloma (MM) in a female patient, who underwent an 8-year course of treatment, including chemotherapy, immunomodulators, hematopoietic stem cell transplantation, CD38 monoclonal antibody, and chimeric antigen receptor T-cell (CAR-T), and was recently diagnosed with concurrent progressive MM and acute myeloid leukemia (AML). This patient has witnessed the evolution of MM treatment paradigms.

CONCLUSION

In this course, disease relapses occurred twice, one of which was manifested by a light chain escape (LCE). Moreover, through the course of the disease in this patient, we review the process of clonal evolution that may be relevant.

New Insights for Polyphenolic Compounds as Naturally Inspired Proteasome Inhibitors

Polyphenols, an important class of natural products, are widely distributed in plant-based foods. These compounds are endowed with several biological activities and exert protective effects in various physiopathological contexts, including cancer. We herein investigated novel potential mechanisms of action of polyphenols, focusing on the proteasome, which has emerged as an attractive therapeutic target in cancers such as multiple myeloma. We carried out a structure-based virtual screening study using the DrugBank database as a repository of FDA-approved polyphenolic molecules. Starting from 86 polyphenolic compounds, based on the theoretical binding affinity and the interactions established with key residues of the chymotrypsin binding site, we selected 2 promising candidates, namely Hesperidin and Diosmin. The further assessment of the biologic activity highlighted, for the first time, the capability of these two molecules to inhibit the β5-proteasome activity and to exert anti-tumor activity against proteasome inhibitor-sensitive or resistant multiple myeloma cell lines.

Nicotinamide-Expanded Allogeneic Natural Killer Cells with CD38 Deletion, Expressing an Enhanced CD38 Chimeric Antigen Receptor, Target Multiple Myeloma Cells

Natural killer (NK) cells are a vital component of cancer immune surveillance. They provide a rapid and potent immune response, including direct cytotoxicity and mobilization of the immune system, without the need for antigen processing and presentation. NK cells may also be better tolerated than T cell therapy approaches and are susceptible to various gene manipulations. Therefore, NK cells have become the focus of extensive translational research. Gamida Cell's nicotinamide (NAM) platform for cultured NK cells provides an opportunity to enhance the therapeutic potential of NK cells. CD38 is an ectoenzyme ubiquitously expressed on the surface of various hematologic cells, including multiple myeloma (MM). It has been selected as a lead target for numerous monoclonal therapeutic antibodies against MM. Monoclonal antibodies target CD38, resulting in the lysis of MM plasma cells through various antibody-mediated mechanisms such as antibody-dependent cellular cytotoxicity (ADCC), complement-dependent cytotoxicity, and antibody-dependent cellular phagocytosis, significantly improving the outcomes of patients with relapsed or refractory MM. However, this therapeutic strategy has inherent limitations, such as the anti-CD38-induced depletion of CD38-expressing NK cells, thus hindering ADCC. We have developed genetically engineered NK cells tailored to treat MM, in which CD38 was knocked-out using CRISPR-Cas9 technology and an enhanced chimeric antigen receptor (CAR) targeting CD38 was introduced using mRNA electroporation. This combined genetic approach allows for an improved cytotoxic activity directed against CD38-expressing MM cells without self-inflicted NK-cell-mediated fratricide. Preliminary results show near-complete abolition of fratricide with a 24-fold reduction in self-lysis from 19% in mock-transfected and untreated NK cells to 0.8% of self-lysis in CD38 knock-out CAR NK cells. Furthermore, we have observed significant enhancements in CD38-mediated activity in vitro, resulting in increased lysis of MM target cell lines. CD38 knock-out CAR NK cells also demonstrated significantly higher levels of NK activation markers in co-cultures with both untreated and αCD38-treated MM cell lines. These NAM-cultured NK cells with the combined genetic approach of CD38 knockout and addition of CD38 CAR represent a promising immunotherapeutic tool to target MM.

Role of the Mitochondrial E3 Ubiquitin Ligases as Possible Therapeutic Targets in Cancer Therapy

Ubiquitination is a post-translational modification that targets specific proteins on their lysine residues. Depending on the type of ubiquitination, this modification ultimately regulates the stability or degradation of the targeted proteins. Ubiquitination is mediated by three different classes of enzymes: the E1 ubiquitin-activating enzymes, the E2 ubiquitin-conjugating enzymes and, most importantly, the E3 ubiquitin ligases. E3 ligases are responsible for the final step of the ubiquitin cascade, interacting directly with the target proteins. E3 ligases can also be involved in DNA repair, cell cycle regulation and response to stress; alteration in their levels can be involved in oncogenic transformation and cancer progression. Of all the six hundred E3 ligases of the human genome, only three of them are specific to the mitochondrion: MARCH5, RNF185 and MUL1. Their alterations (that reflect on the alteration of the mitochondria functions) can be related to cancer progression, as underlined by the increasing research performed in recent years on these three mitochondrial enzymes. This review will focus on the function and mechanisms of the mitochondrial E3 ubiquitin ligases, as well as their important targets, in cancer development and progression, also highlighting their potential use for cancer therapy.

The versatility of the proteasome in gene expression and silencing: Unraveling proteolytic and non-proteolytic functions

The 26S proteasome consists of a 20S core particle and a 19S regulatory particle and critically regulates gene expression and silencing through both proteolytic and non-proteolytic functions. The 20S core particle mediates proteolysis, while the 19S regulatory particle performs non-proteolytic functions. The proteasome plays a role in regulating gene expression in euchromatin by modifying histones, activating transcription, initiating and terminating transcription, mRNA export, and maintaining transcriptome integrity. In gene silencing, the proteasome modulates the heterochromatin formation, spreading, and subtelomere silencing by degrading specific proteins and interacting with anti-silencing factors such as Epe1, Mst2, and Leo1. This review discusses the proteolytic and non-proteolytic functions of the proteasome in regulating gene expression and gene silencing-related heterochromatin formation. This article is part of a special issue on the regulation of gene expression and genome integrity by the ubiquitin-proteasome system.

Developing Targeted Therapies for T Cell Acute Lymphoblastic Leukemia/Lymphoma

PURPOSE OF REVIEW

Largely, treatment advances in relapsed and/or refractory acute lymphoblastic leukemia (ALL) have been made in B cell disease leaving T cell ALL reliant upon high-intensity chemotherapy. Recent advances in the understanding of the biology of T-ALL and the improvement in immunotherapies have led to new therapeutic pathways to target and exploit. Here, we review the more promising pathways that are able to be targeted and other therapeutic possibilities for T-ALL.

RECENT FINDINGS

Preclinical models and early-phase clinical trials have shown promising results in some case in the treatment of T-ALL. Targeting many different pathways could lead to the next advancement in the treatment of relapsed and/or refractory disease. Recent advances in cellular therapies have also shown promise in this space. When reviewing the literature as a whole, targeting important pathways and antigens likely will lead to the next advancement in T-ALL survival since intensifying chemotherapy.

Late versus early response and depth of response are associated with improved outcomes in patients with newly diagnosed multiple myeloma enrolled in the TOURMALINE-MM2 trial

Deeper responses are associated with longer survival in multiple myeloma (MM); however, limited data exist on the impact of response kinetics on outcomes. We investigated progression-free survival (PFS) and duration of response (DOR) by response depth and in early (best confirmed response 0-4 months; n = 424) versus late responders (best confirmed response >4 months; n = 281). Newly diagnosed patients enrolled in TOURMALINE-MM2 receiving ixazomib-lenalidomide-dexamethasone (IRd) (n = 351) or placebo-Rd (n = 354) were evaluated post hoc. Deeper responses were associated with longer PFS (complete response [CR] not reached [NR], very good partial response [VGPR] 37.2 months, partial response [PR] 16.4 months) and DOR (CR NR, VGPR 42.6 months, PR 15.4 months). Among patients with a PFS (n = 511) or DOR (n = 484) of ≥6 months who achieved ≥PR, median PFS was prolonged among late versus early responders receiving IRd (59.7 vs. 17.9 months) or placebo-Rd (56.6 vs. 12.4 months), as was median DOR (IRd, NR vs. 20.9 months; placebo-Rd, 58.2 vs. 11.7 months). While the treatment paradigm for newly diagnosed MM is treatment to progression, our findings suggest slowness of response to a proteasome inhibitor-immunomodulatory drug-steroid combination is not a negative predictor of outcome.

Current approach to Waldenström macroglobulinemia

Waldenström macroglobulinemia (WM) is a unique CD20+, B-cell non-Hodgkin lymphoma, characterized by lymphoplasmacytic infiltration of the bone marrow and circulating monoclonal immunoglobulin M. The clinical manifestations and outcomes of patients are highly variable. High-level evidence supports integration of monoclonal anti-CD20 antibody, rituximab, to the chemotherapy backbone to treat WM. However, its contemporary management has become more nuanced, with deeper understanding of the pathophysiology and incorporation of Bruton's tyrosine kinase (BTK) inhibitors to the treatment paradigm. Prior knowledge of the patients' MYD88L265P and CXCR4 mutation status may aid in the treatment decision-making. Currently, the two frequently utilized approaches include fixed-duration chemoimmunotherapy and BTK inhibitor-based continuous treatment until progression. Randomized trials comparing these two vastly divergent approaches are lacking. Recent studies demonstrating efficacy of B cell lymphoma-2 (BCL2) inhibitors and non-covalent BTK inhibitors in patients, previously exposed to a covalent BTK inhibitor, are a testament to the rapidly expanding options against WM.

Real-world data on the effectiveness and safety of Ixazomib-Lenalidomide-Dexamethasone therapy in relapsed/refractory multiple myeloma patients: a multicenter experience in Turkey

A multicenter, retrospective, observational study was conducted to explore effectiveness and safety of ixazomib plus lenalidomide with dexamethasone (IRd) in relapsed/refractory multiple myeloma (RRMM) patients following at least ≥ two lines of therapy. Patients' treatment responses, overall response rate, progression-free survival rate, and adverse events were recorded. Mean age of 54 patients was 66.5 ± 9.1 years. There were 20 patients (37.0%) with progression. Median progression-free survival was 13 months in patients who received a median of three therapy lines in a 7.5-month follow-up period. Overall response rate was 38.5%. Of 54 patients, 19 (40.4%) had at least one adverse event, and nine (19.1%) had an adverse event of at least grade 3 or more. Of 72 adverse events observed in 47 patients, 68% were grade 1 or 2. Treatment was not stopped in any patient due to adverse events. IRd combination therapy was effective and safe in heavily treated RRMM patients.

Recommendations for Management of Secondary Antibody Deficiency in Multiple Myeloma

Secondary antibody deficiency (SAD) is a subtype of secondary immunodeficiency characterized by low serum antibody concentrations (hypogammaglobulinemia) or poor antibody function. SAD is common in patients with multiple myeloma (MM) due to underlying disease pathophysiology and treatment-related immune system effects. Patients with SAD are more susceptible to infections and infection-related morbidity and mortality. With therapeutic advancements improving MM disease control and survival, it is increasingly important to recognize and treat the often-overlooked concurrent immunodeficiency present in patients with MM. The aims of this review are to define SAD and its consequences in MM, increase SAD awareness, and provide recommendations for SAD management. Based on expert panel discussions at a standalone meeting and supportive literature, several recommendations were made. Firstly, all patients with MM should be suspected to have SAD regardless of serum antibody concentrations. Patients should be evaluated for immunodeficiency at MM diagnosis and stratified into management categories based on their individualized risk of SAD and infection. Infection-prevention strategy education, early infection reporting, and anti-infective prophylaxis are key. We recommend prophylactic antibiotics or immunoglobulin replacement therapy (IgRT) should be considered in patients with severe hypogammaglobulinemia associated with a recurrent or persistent infection. To ensure an individualized and efficient treatment approach is utilized, patient's immunoglobin G concentration and infection burden should be closely monitored throughout treatment. Patient choice regarding route and IgRT treatment is also key in reducing treatment burden. Together, these recommendations and proposed management algorithms can be used to aid physician decision-making to improve patient outcomes.

Differential Diagnosis and Therapeutic Advances in Multiple Myeloma: A Review Article

Multiple myeloma (MM) is a hematologic malignancy characterized by the abnormal clonal proliferation of plasma cells that may result in focal bone lesions, renal failure, anemia, and/or hypercalcemia. Recently, the diagnosis and treatment of MM have evolved due to a better understanding of disease pathophysiology, improved risk stratification, and new treatments. The incorporation of new drugs, including proteasome inhibitors, immunomodulatory drugs, anti-CD38 antibodies and high-dose chemotherapy followed by hematopoietic stem cell transplantation, has resulted in a significant improvement in patient outcomes and QoL. In this review, we summarize differential diagnoses and therapeutic advances in MM.

Structural elucidation of recombinant Trichomonas vaginalis 20S proteasome bound to covalent inhibitors

Proteasomes are essential for protein homeostasis in mammalian cells1-4 and in protozoan parasites such as Trichomonas vaginalis (Tv).5 Tv and other protozoan 20S proteasomes have been validated as druggable targets.6-8 However, in the case of Tv 20S proteasome (Tv20S), biochemical and structural studies were impeded by low yields and purity of the native proteasome. We successfully made recombinant Tv20S by expressing all seven α and seven β subunits together with the Ump-1 chaperone in insect cells. We isolated recombinant proteasome and showed that it was biochemically indistinguishable from the native enzyme. We confirmed that the recombinant Tv20S is inhibited by the natural product marizomib (MZB)9 and the recently developed peptide inhibitor carmaphycin-17 (CP-17)8,10. Specifically, MZB binds to the β1, β2 and β5 subunits, while CP-17 binds the β2 and β5 subunits. Next, we obtained cryo-EM structures of Tv20S in complex with these covalent inhibitors at 2.8Å resolution. The structures revealed the overall fold of the Tv20S and the binding mode of MZB and CP-17. Our work explains the low specificity of MZB and higher specificity of CP-17 towards Tv20S as compared to human proteasome and provides the platform for the development of Tv20S inhibitors for treatment of trichomoniasis.

Cytotoxic and Apoptotic Effects of Pinostilbene and Bortezomib Combination Treatment on Human Multiple Myeloma Cells

Multiple myeloma (MM) is a cancer of plasma cells in the bone marrow characterized by bone lesions, hypercalcemia, anemia, and renal failure. Bortezomib (BTZ), a common treatment for MM, is a proteasome inhibitor that induces apoptosis in MM cells. However, high doses of BTZ can be very toxic, signifying a need for a synergistic drug combination to improve treatment efficacy. Resveratrol (RES), a phenolic compound found in grapes, has been shown to inhibit MM cell growth. We sought to identify a synergistic combination of BTZ with a RES derivative and analyze the effects on reducing viability and inducing apoptosis in human MM cells. BTZ as well as RES and its derivatives pinostilbene (PIN) and piceatannol (PIC) decreased MM cell viability in a dose- and time-dependent manner and increased expression of cleaved proapoptotic proteins poly(ADP-ribose) polymerase 1 (PARP1) and caspase-3 in a dose-dependent manner. The combination of 5 nM BTZ and 5 μM PIN was identified to have synergistic cytotoxic effects in MM RPMI 8226 cells. MM RPMI 8226 cells treated with this combination for 24 h showed increased cleaved PARP1 and caspase-3 expression and higher percentages of apoptotic cells versus cells treated with the individual compounds alone. The treatment also showed increased apoptosis induction in MM RPMI 8226 cells co-cultured with human bone marrow stromal HS-5 cells in a Transwell model used to mimic the bone marrow microenvironment. Expression of oxidative stress defense proteins (catalase, thioredoxin, and superoxide dismutase) in RPMI 8226 cells were reduced after 24 h treatment, and cytotoxic effects of the treatment were ameliorated by antioxidant N-acetylcysteine (NAC), suggesting the treatment impacts antioxidant levels in RPMI 8226 cells. Our results suggest that this combination of BTZ and PIN decreases MM cell viability synergistically by inducing apoptosis and oxidative stress in MM cells.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The roles of proteases in prostate cancer

Since the proposition of the pro-invasive activity of proteolytic enzymes over 70 years ago, several roles for proteases in cancer progression have been established. About half of the 473 active human proteases are expressed in the prostate and many of the most well-characterized members of this enzyme family are regulated by androgens, hormones essential for development of prostate cancer. Most notably, several kallikrein-related peptidases, including KLK3 (prostate-specific antigen, PSA), the most well-known prostate cancer marker, and type II transmembrane serine proteases, such as TMPRSS2 and matriptase, have been extensively studied and found to promote prostate cancer progression. Recent findings also suggest a critical role for proteases in the development of advanced and aggressive castration-resistant prostate cancer (CRPC). Perhaps the most intriguing evidence for this role comes from studies showing that the protease-activated transmembrane proteins, Notch and CDCP1, are associated with the development of CRPC. Here, we review the roles of proteases in prostate cancer, with a special focus on their regulation by androgens.

Mechanistic Pharmacokinetic/Pharmacodynamic Modeling in Support of a Patient-Convenient, Longer Dosing Interval for Carfilzomib, a Covalent Inhibitor of the Proteasome

BACKGROUND

Carfilzomib is an irreversible second-generation proteasome inhibitor that has a short elimination half-life but much longer pharmacodynamic (PD) effect based on its irreversible mechanism of action, making it amenable to longer dosing intervals. A mechanistic pharmacokinetic/pharmacodynamic (PK/PD) model was built using a bottom-up approach, based on the mechanism of action of carfilzomib and the biology of the proteasome, to provide further evidence of the comparability of once-weekly and twice-weekly dosing.

METHODS

The model was qualified using clinical data from the phase III ENDEAVOR study, where the safety and efficacy of bortezomib (a reversible proteasome inhibitor) and carfilzomib were compared. Simulations were performed to compare the average proteasome inhibition across five cycles of treatment for the 20/70 mg/m² once-weekly (70 QW) and 20/56 mg/m² twice-weekly (56 BIW) regimens.

RESULTS

Results indicated that while 70 QW had a higher maximum concentration (C_max) and lower steady-state area under the concentration-time curve (AUC) than 56 BIW, the average proteasome inhibition after five cycles of treatment between the regimens was comparable. Presumably, the higher C_max of carfilzomib from 70 QW compensates for the lower overall AUC compared with 56 BIW, and hence 70 QW is expected to have comparable proteasome inhibition, and therefore comparable efficacy, to 56 BIW. The comparable model-predicted proteasome inhibition between 70 QW and 56 BIW also translated to comparable clinical response, in terms of overall response rate and progression-free survival.

CONCLUSION

This work provides a framework for which mechanistic PK/PD modeling can be used to guide optimization of dosing intervals for therapeutics with significantly longer PD effects than PK, and help further justify patient-convenient, longer dosing intervals.

Euchromatic Histone Lysine Methyltransferase 2 Inhibition Enhances Carfilzomib Sensitivity and Overcomes Drug Resistance in Multiple Myeloma Cell Lines

Proteasome inhibitors (PIs) are extensively used for the therapy of multiple myeloma. However, patients continuously relapse or are intrinsically resistant to this class of drugs. In addition, adverse toxic effects such as peripheral neuropathy and cardiotoxicity could arise. Here, to identify compounds that can increase the efficacy of PIs, we performed a functional screening using a library of small-molecule inhibitors covering key signaling pathways. Among the best synthetic lethal interactions, the euchromatic histone-lysine N-methyltransferase 2 (EHMT2) inhibitor UNC0642 displayed a cooperative effect with carfilzomib (CFZ) in numerous multiple myeloma (MM) cell lines, including drug-resistant models. In MM patients, EHMT2 expression correlated to worse overall and progression-free survival. Moreover, EHMT2 levels were significantly increased in bortezomib-resistant patients. We demonstrated that CFZ/UNC0642 combination exhibited a favorable cytotoxicity profile toward peripheral blood mononuclear cells and bone-marrow-derived stromal cells. To exclude off-target effects, we proved that UNC0642 treatment reduces EHMT2-related molecular markers and that an alternative EHMT2 inhibitor recapitulated the synergistic activity with CFZ. Finally, we showed that the combinatorial treatment significantly perturbs autophagy and the DNA damage repair pathways, suggesting a multi-layered mechanism of action. Overall, the present study demonstrates that EHMT2 inhibition could provide a valuable strategy to enhance PI sensitivity and overcome drug resistance in MM patients.

Current status of drug development for patients with multiple myeloma: a review of comparison in China and the rest of world

Multiple myeloma (MM) is a highly heterogeneous malignancy. The treatment of MM has been significantly advanced in recent years. B cell maturation antigen (BCMA)-targeted immunotherapy and chimeric antigen receptor T (CAR-T) cell therapy have been approved for the treatment of relapsed and refractory MM (RRMM), which will be launched in China shortly. The CD38 (cluster of differentiation 38) antibody, daratumumab, improves the clinical outcomes both RRMM and newly diagnosed MM patients. The combination of daratumumab, bortezomib and dexamethasone achieved favorable outcomes as the first-line therapy in China. However, high-risk patients have limited benefits from these advanced therapeutics, and usually relapse early, progressing into aggressive end-stage MM. Therefore, novel therapies are sought to improve the cancer prognosis in these patients. This review furnishes an overview of the recent clinical developments of these novel drugs and compares the drug candidates under development in China to the rest of the world.

Serum soluble BCMA can be used to monitor relapse of multiple myeloma patients after chimeric antigen receptor T-cell immunotherapy

PURPOSE

Chimeric antigen receptor T-cell (CAR-T) therapy has been proven very effective in treating hematologic malignancies. Ciltacabtagene autoleucel (cilta-cel), a second-generation CAR-T cell with double B cell maturation antigen (BCMA) targeting binding domains, showed an 88% overall response rate (ORR) in patients with relapsed/refractory multiple myeloma (MM), which were carried out in our institute. This study aimed to assess the prognostic potential of soluble BCMA (sBCMA) in serum as a biomarker in MM after CAR-T therapy.

PATIENTS AND METHODS

Serum samples (n = 44) from MM patients were collected before and after CAR-T therapy. The level of sBCMA was analyzed by enzyme-linked immunosorbent assay (ELISA). Additionally, three patients' long-term longitudinal analysis were performed.

RESULTS

Serum sBCMA level was correlated with the percentage of malignant plasma cells in bone marrow (r = 0.613). After CAR-T infusion, the sBCMA level in serum of MM patients decreased markedly (median: 508,513 pg/mL before CAR-T infusion, 89,198 pg/mL in the first month, 8448 pg/mL in the second months, and 6010 pg/mL in the third month after CAR-T infusion). In patients who obtained objective response (≥ PR), re-elevated sBCMA indicated the possibility of disease recurrence. At a cutoff 69,326.27 pg/mL, sBCMA shows high sensitivity (87.5%) and specificity (88.5%) for identifying relapse of MM after CAR-T therapy.

CONCLUSION

Our results suggested that serum sBCMA level changes in response to the clinical status of MM patients after anti-BCMA CAR-T therapy. Furthermore, sBCMA may be a auxiliary biomarker for disease monitoring in MM patients after CAR-T therapy.

Anti-Angiogenic Activity of Drugs in Multiple Myeloma

Angiogenesis represents a pivotal hallmark of multiple myeloma (MM) that correlates to patients’ prognosis, overall survival, and drug resistance. Hence, several anti-angiogenic drugs that directly target angiogenic cytokines (i.e., monoclonal antibodies, recombinant molecules) or their cognate receptors (i.e., tyrosine kinase inhibitors) have been developed. Additionally, many standard antimyeloma drugs currently used in clinical practice (i.e., immunomodulatory drugs, bisphosphonates, proteasome inhibitors, alkylating agents, glucocorticoids) show anti-angiogenic effects further supporting the importance of inhibiting angiogenesis from potentiating the antimyeloma activity. Here, we review the most important anti-angiogenic therapies used for the management of MM patients with a particular focus on their pharmacological profile and on their anti-angiogenic effect in vitro and in vivo. Despite the promising perspective, the direct targeting of angiogenic cytokines/receptors did not show a great efficacy in MM patients, suggesting the need to a deeper knowledge of the BM angiogenic niche for the design of novel multi-targeting anti-angiogenic therapies.

Yeast Ribonucleotide Reductase Is a Direct Target of the Proteasome and Provides Hyper Resistance to the Carcinogen 4-NQO

Various external and internal factors damaging DNA constantly disrupt the stability of the genome. Cells use numerous dedicated DNA repair systems to detect damage and restore genomic integrity in a timely manner. Ribonucleotide reductase (RNR) is a key enzyme providing dNTPs for DNA repair. Molecular mechanisms of indirect regulation of yeast RNR activity are well understood, whereas little is known about its direct regulation. The study was aimed at elucidation of the proteasome-dependent mechanism of direct regulation of RNR subunits in Saccharomyces cerevisiae. Proteome analysis followed by Western blot, RT-PCR, and yeast plating analysis showed that upregulation of RNR by proteasome deregulation is associated with yeast hyper resistance to 4-nitroquinoline-1-oxide (4-NQO), a UV-mimetic DNA-damaging drug used in animal models to study oncogenesis. Inhibition of RNR or deletion of RNR regulatory proteins reverses the phenotype of yeast hyper resistance to 4-NQO. We have shown for the first time that the yeast Rnr1 subunit is a substrate of the proteasome, which suggests a common mechanism of RNR regulation in yeast and mammals.

Past, Present, and a Glance into the Future of Multiple Myeloma Treatment

Multiple myeloma (MM) is a challenging hematological cancer which typically grows in bone marrow. MM accounts for 10% of hematological malignancies and 1.8% of cancers. The recent treatment strategies have significantly improved progression-free survival for MM patients in the last decade; however, a relapse for most MM patients is inevitable. In this review we discuss current treatment, important pathways for proliferation, survival, immune suppression, and resistance that could be targeted for future treatments.

Real-world assessment of the treatment patterns and outcomes among patients with multiple myeloma across different risk stratification criteria in the United States: a retrospective cohort study

This study evaluated prognostic performance of International Staging System (ISS), revised ISS, and chromosomal abnormalities (CA) in newly diagnosed multiple myeloma patients to describe treatment patterns (cohort 1; n = 1979) and survival outcomes (cohort 2; n = 1382). In both cohorts, ∼18%, 41%, and 37% of patients were high-risk according to the R-ISS, ISS, and high-risk CA criteria, respectively. Across all risk stratification criteria, 60% of patients received triplets. In cohort 2, the median modified progression-free survival decreased with each increasing risk stage (23.5, 12.1, and 8.8 months in R-ISS I, II, and III, respectively, and 16.0, 12.7, and 10.4 months in ISS I, II, and III). Similar trends were observed in the proportions of two-year overall survival. In conclusion, R-ISS has greater discriminatory power than ISS or high-risk CA alone and can be implemented in a real-world setting. Accordingly, a more risk-adapted approach can be feasible, with a greater population-level impact.