Multiple Myeloma: Current Advances and Future Directions

Validation of the FACT-G7 in patients with hematologic malignancies

Background

It is essential to evaluate the quality of life in patients with hematologic malignancies to reflect the therapeutic effect and prognosis, but lengthy assessments are often burdensome. The 7-Item Functional Assessment of Cancer Therapy-General (FACT-G7) is a brief, easy, and rapid index for evaluating quality of life. Nevertheless, there is no report about its application in Chinese patients with hematologic malignancies.

Objective

The purpose of this study was to validate the Chinese version of the FACT-G7 for patients with hematologic malignancies.

Methods

This study is a cross-sectional study. A total of 855 patients with hematologic malignancies completed the Functional Assessment of Cancer Therapy-General (FACT-G) and were scored the Eastern Cooperative Oncology Group Performance Status (ECOG-PS) by nurses. Cronbach's alpha, confirmatory factor analyses, Pearson's correlation, and one-way analysis of variance were conducted to evaluate internal consistent reliability, structural validity and concurrent validity.

Results

The FACT-G7 showed acceptable internal consistency, as indicated by a Cronbach's alpha of 0.73. The confirmatory factor analyses test for single-factor model fit for the FACT-G7 scale was almost adequate. The satisfactory correlations between the FACT-G7 and the FACT-G and its subscales, and ECOG-PS groups differed in FACT-G7 scores demonstrating concurrent validity.

Conclusion

This study suggested that the Chinese version of the FACT-G7 provides a useful and rapid measure for assessing quality of life in Chinese patients with hematologic malignancies, which providing a reference for further evaluation and care.

Cost effectiveness analysis of CAR-T cell therapy for patients with relapsed/refractory multiple myeloma in China

BACKGROUND

The landscape of treatment strategies for relapsed/refractory multiple myeloma (RRMM) has dramatically changed due to the emergence of chimeric antigen receptor T (CAR-T) cell therapy. The aim of this study was to evaluate the cost-effectiveness of two CAR-T cell treatments for RRMM patients from the perspective of the Chinese healthcare system.

METHODS

Markov model was used to compare currently available salvage chemotherapy with Idecabtagene vicleucel (Ide-cel) and Ciltacabtagene autoleucel (Cilta-cel) for treatment of patients with RRMM. The model was developed based on data from three studies: CARTITUDE-1, KarMMa and MAMMOTH. The healthcare cost and utility of RRMM patients were collected from a provincial clinical center in China.

RESULTS

In the base case analysis, 3.4% and 30.6% of RRMM patients were expected to be long-term survivors after 5 years of Ide-cel and Cilta-cel treatment, respectively. Compared to salvage chemotherapy, Ide-cel and Cilta-cel were associated with incremental QALYs of 1.19 and 3.31, and incremental costs of US $140,693 and $119,806, leading to ICERs of $118,229 and $36,195 per QALY, respectively. At an ICER threshold of $37,653/QALY gained, the probability that Ide-cel and Cilta-cel are cost-effective were estimated to be 0% and 72%, respectively. With younger target people entering the model, and partitioned survival model in scenario analysis, the ICERs of Cilta-cel and Ide-cel changed rather mildly and their cost-effectiveness results were same to base analysis.

CONCLUSIONS

Base on the willingness-to-pay of 3 times China's per capita GDP in 2021, Cilta-cel was considered to be a more cost-effective option compared to salvage chemotherapy for RRMM in China, while Ide-cel was not.

Antiproliferative activity of compounds isolated from the root bark of Lannea acida in multiple myeloma cell lines

Lannea acida A. Rich. is a native plant of West Africa used in traditional medicine against diarrhea, dysentery, rheumatism, and women infertility. Eleven compounds were isolated from the dichloromethane root bark extract using various chromatographic techniques. Among those, nine compounds have not been previously reported, i.e. one cardanol derivative, two alkenyl 5-hydroxycyclohex-2-en-1-ones, three alkenyl cyclohex-4-ene-1,3-diols, two alkenyl 7-oxabicyclo[4.1.0]hept-4-en-3-ols, and one alkenyl 4,5-dihydroxycyclohex-2-en-1-one, together with two known cardanols. The structure of the compounds was elucidated using NMR, HRESIMS, ECD, IR, and UV. Their antiproliferative activity was evaluated in three multiple myeloma cell lines: RPMI 8226, MM.1S, and MM.1R. Two compounds showed activity in all cell lines with IC₅₀ values < 5 μM. Further investigations are needed to understand the mechanism of action.

Antibody drug conjugates for the treatment of multiple myeloma

The treatment landscape of multiple myeloma (MM) has evolved substantially, but it remains largely incurable so new treatment options are required. Antibody drug conjugates (ADCs) are an emerging therapeutic class used in Cancer to deliver targeted therapy. ADCs are composed of three components, an antibody, a chemical linker and a payload which must be chosen carefully to be effective and safe. This alternative mechanism of action to standard treatments makes ADCs an attractive class for further development. However, several ADCs have been investigated but many have not moved further than phase 1 trials, highlighting the challenges in designing an effective and tolerable ADC. Belantamab Mafodotin is currently the only ADC licensed for MM although others are currently under evaluation. Belantamab Mafodotin demonstrated efficacy as monotherapy in triple class exposed patients and combinations are under development which maintain safety with encouraging efficacy particularly at earlier lines of therapy. Retaining an acceptable adverse event profile for ADCs remains vital for their success. Strategies to mitigate ocular events for Belantamab Mafodotin involve lower and less frequent dosing as well as the use of gamma secretase inhibitors. The optimal sequencing of ADCs within the treatment pathway including novel immunotherapies is now under evaluation.

Exploring the potential of combining IL-2-activated NK cells with an anti-PDL1 monoclonal antibody to target multiple myeloma-associated macrophages

Multiple myeloma (MM) is an incurable disease, characterized by malignant plasma cells in the bone marrow. MM growth is largely dependent on the tumor microenvironment (TME), consisting of complex cellular networks that shape a tumor-permissive environment. Within the TME, tumor-associated cells (TAC) comprise heterogeneous cell populations that collectively support immunosuppression. Reshaping the TME toward an immunostimulatory environment may enhance effectiveness of immunotherapies. Here, we investigated interactions between donor-derived natural killer (NK) cells and TAC, like tumor-associated macrophages (TAM) and M1 macrophages, and assessed whether anti-tumor effector functions of NK cells could be enhanced by an ADCC-triggering antibody targeting macrophages. Monocytes were polarized in vitro toward either M1 or TAM before co-culture with high-dose IL-2-activated NK cells. NK cell responses were assessed by measuring degranulation (CD107a) and IFN-γ production. We found that NK cells degranulated and produced IFN-γ upon interaction with both macrophage types. NK cell responses against PD-L1⁺ M1 macrophages could be further enhanced by Avelumab, an anti-PD-L1- and ADCC-inducing antibody. Additionally, NK cell responses were influenced by HLA class I, shown by stronger degranulation in NK cell subsets for which the corresponding HLA ligand was absent on the macrophage target cells (KIR-ligand mismatch) compared to degranulation in the presence of the HLA ligand (KIR-ligand match). Our results suggest that NK cells could, next to killing tumor cells, get activated upon interaction with TAC, like M1 macrophages and TAMs, and that NK cells combined with PD-L1 blocking antibodies with ADCC potential could, through IFN-γ secretion, promote a more immune-favorable TME.

Isolation and Structure Elucidation of Compounds from Sesamum alatum and Their Antiproliferative Activity against Multiple Myeloma Cells

The phytochemical investigation of the dichloromethane root extract of Sesamum alatum led to the isolation of 18 compounds. Among these, compounds 3-8, defined as 9-hydroxy-2,2-dimethyl-2H-benzo[g]chromene-5,10-dione 6-O-β-d-glucopyranoside (3), (2S,3R)-3,4,7-trihydroxy-2-(3'-methylbut-2'-en-1'-yl)-2,3-dihydro-1H-inden-1-one (4), (Z)-2-(1',4'-dihydroxy-4'-methylpent-2'-en-1'-ylidene)-4,7-dihydroxy-1H-indene-1,3(2H)-dione (5), (S)-2,5,8-trihydroxy-3-(2'-hydroxy-3'-methylbut-3'-en-1'-yl)naphthalene-1,4-dione (6), 6-hydroxy-3-(3'-methylbut-2'-en-1'-yl)-4-oxo-4H-chromene-5-carboxylic acid (7), and (S)-2-(1'-hydroxy-4'-methylpent-3'-en-1'-yl)anthracene-9,10-dione (8), respectively, have not yet been described. Their structures were elucidated based on spectroscopic data analysis, including IR, NMR, HRESIMS and ECD measurements. Additional known compounds, namely, hydroxysesamone (1), anthrasesamone A (2), 2,6-dimethoxy-1,4-benzoquinone (9), syringic acid (10), syringaresinol (11), 2,3-epoxysesamone 8-O-β-d-glucopyranoside (12), 2,3-diacetylmartinoside (13), 2,3-epoxy-4,5,8-trihydroxy-2-prenyl-1-tetralone (14), ursolic acid (15), chlorosesamone (16), 2,3-epoxysesamone (17), and 2-(4-methyl-3-pentenyl)anthraquinone (18) were isolated. The antiproliferative activity of the compounds was tested against the RPMI 8226 multiple myeloma cell line. When compounds presented an IC₅₀ value <10 μM, they were tested against two other multiple myeloma cell lines, MM.1S and MM.1R. Compound 17 was found to be the most potent, with IC₅₀ values of 0.6, 0.7, and 0.9 μM, respectively, for the three cell lines.

Targeting phase separation on enhancers induced by transcription factor complex formations as a new strategy for treating drug-resistant cancers

The limited options for treating patients with drug-resistant cancers have emphasized the need to identify alternative treatment targets. Tumor cells have large super-enhancers (SEs) in the vicinity of important oncogenes for activation. The physical process of liquid-liquid phase separation (LLPS) contributes to the assembly of several membrane-less organelles in mammalian cells. Intrinsically disordered regions (IDRs) of proteins induce LLPS formation by developing condensates. It was discovered that key transcription factors (TFs) undergo LLPS in SEs. In addition, TFs play critical roles in the epigenetic and genetic regulation of cancer progression. Recently, we revealed the essential role of disease-specific TF collaboration changes in advanced prostate cancer (PC). OCT4 confers epigenetic changes by promoting complex formation with TFs, such as Forkhead box protein A1 (FOXA1), androgen receptor (AR) and Nuclear respiratory factor 1 (NRF1), inducing PC progression. It was demonstrated that TF collaboration through LLPS underlying transcriptional activation contributes to cancer aggressiveness and drug resistance. Moreover, the disruption of TF-mediated LLPS inhibited treatment-resistant PC tumor growth. Therefore, we propose that repression of TF collaborations involved in the LLPS of SEs could be a promising strategy for advanced cancer therapy. In this article, we summarize recent evidence highlighting the formation of LLPS on enhancers as a potent therapeutic target in advanced cancers.

Phytochemical Investigation of the Roots of Ipomoea asarifolia and Antiproliferative Activity of the Isolated Compounds against Multiple Myeloma Cells

Ipomoea asarifolia is a herbaceous plant belonging to the family Convolvulaceae and is native to tropical regions of Africa, America, and Asia. A dichloromethane root extract showed antiproliferative activity against multiple myeloma cells (RPMI 8226). The phytochemical investigation led to the isolation of 15 compounds. Compounds 1-4, named (4S,8S)-1-(furan-3-yl)-9-hydroxy-4,8-dimethylnonane-1,6-dione, isoferulic acid hexadecyl ester, caffeic acid hexadecyl ester, and asarifolin I, respectively, are described for the first time. The structures of these molecules were established from their NMR, UV, IR spectroscopic, and MS data. 4-Hydroxycinnamic acid hexadecyl ester (5), 4-hydroxycinnamic acid octadecyl ester (6), 4-hydroxycinnamic acid eicosyl ester (7), caffeic acid octadecyl ester (8), pescapreins III, IV, XXI, XXIII, XXV, and XXVI (9-14), and stoloniferin III (15) were also isolated. All compounds were tested against a multiple myeloma cell line (RPMI 8226). When their IC₅₀ value was lower than 10 μM, the compounds were also tested against two other multiple myeloma cell lines, MM.1S and MM.1R. Compound 3 was the most potent, with an IC₅₀ value of 3.0 μM against RPMI 8226 cells.

Daratumumab utilization and cost analysis among patients with multiple myeloma in a US community oncology setting

Background: The introduction of daratumumab into the treatment of multiple myeloma has improved outcomes in patients; however, community oncologists often dose more frequently than the US FDA-approved label. Materials and methods: Integra analyzed its database to elucidate daratumumab treatment patterns and the impact of increased utilization on the cost of care for multiple myeloma. Results: Following week 24, 671 (65%) of 1037 patients remained on daratumumab-containing regimens, with 330 patients continuing more frequent treatments than the expected once-every-4-weeks dosing described in the standard dosing schedule. Patients received an average of 14% more daratumumab doses than the FDA-approved label indicates, increasing the 1-year daratumumab costs by an estimated US$31,353. Conclusion: Daratumumab is utilized more frequently than the FDA-recommended dosing, leading to higher multiple myeloma treatment costs.

Lenalidomide, bortezomib and dexamethasone followed by tandem- autologous stem cell transplantation is an effective treatment modality for multi-hit multiple myeloma

In order to investigate the efficacy of lenalidomide, bortezomib and dexamethasone (VRD) induction chemotherapy regimen combined with tandem autologous stem cell transplantation (ASCT) in treating multi-hit multiple myeloma (MM), we analyzed 252 cases of newly diagnosed MM treated with the bortezomib-containing induction chemotherapy from June 2016 to June 2019. According to the fluorescence in situ hybridization (FISH) results on diagnosis, the patients were divided into multi-hit MM group (47 cases), single-hit MM group (81 cases), and standard-risk group (124 cases). Our analysis showed that R-ISS stageⅢ in transplantation group and R-ISS stageⅢ, multi-hit and VGPR or above was not achieved at the fourth cycle of chemotherapy in non-transplantation group were independent factors for poor prognosis by univariate and multivariate analyses. Moreover, the overall response rate (ORR) of VRD induction chemotherapy group was significantly higher than that of the non-VRD group in the single-hit and multi-hit groups (P = 0.021, P = 0.032); In terms of ASCT, tandem-ASCT can significantly improve the 2-year PFS (77.8 ± 3.9 %) and OS (83.3 ± 5.6 %) of multi-hit MM (P = 0.024, P = 0.037), while single-ASCT only has a limited effect on PFS (61.5 ± 3.0 %) and OS (71.9 ± 4.5 %) (P = 0.115, P = 0.155).

Identification of three immune molecular subtypes associated with immune profiles, immune checkpoints, and clinical outcome in multiple myeloma

Purpose

To identify the immune molecular subtype for MM to help achieve individualized and precise targeted therapy.

Methods

The GDC API was used to download the TCGA‐MM profile dataset, which contains 859 samples in total, all of which were anterior to the standard treatment after diagnosis. Moreover, 282, 298, and 258 samples were stage I, stage II, and stage III separately. We used the immune gene expression profile for consistent clustering; and used the R software package ConsensusClusterPlus to sort the immune molecular subtypes. Correlation between subtypes and clinical features, immunity, and prognosis was then analyzed.

Results

A total of 859 tumor samples were separated into these three subtypes, which were not meaningfully related to age or sex but showed a remarkable association with stage. The results suggested that obvious differences in immune metagene expression and expression of 10 immune checkpoint genes appeared among the three subtypes.

Conclusion

The three subtypes are distinctly different in terms of immune metagenes, immune checkpoint molecules, and clinical prognosis. The discovery of the immune microenvironment of MM could further reveal the strategy for immunotherapy in MM and provide a promising candidate prognostic tool for survival.

Proteomics-Based Approach Reveals the Involvement of SERPINB9 in Recurrent and Relapsed Multiple Myeloma

Multiple myeloma (MM) is a common hematological malignancy with poorly understood recurrence and relapse mechanisms. Notably, bortezomib resistance leading to relapse makes MM treatment significantly challenging. To clarify the drug resistance mechanism, we employed a quantitative proteomics approach to identify differentially expressed protein candidates implicated in bortezomib-resistant recurrent and relapsed MM (RRMM). Bone marrow aspirates from five patients newly diagnosed with MM (NDMM) were compared with those from five patients diagnosed with bortezomib-resistant RRMM using tandem mass tag-mass spectrometry (TMT-MS). Subcellular localization and functional classification of the differentially expressed proteins were determined by gene ontology, Kyoto Encyclopedia of Genes and Genomes pathway, and hierarchical clustering analyses. The top candidates identified were validated with parallel reaction monitoring (PRM) analysis using tissue samples from 11 NDMM and 8 RRMM patients, followed by comparison with the NCBI Gene Expression Omnibus (GEO) dataset of 10 MM patients and 10 healthy controls (accession no.: GSE80608). Thirty-four differentially expressed proteins in RRMM, including proteinase inhibitor 9 (SERPINB9), were identified by TMT-MS. Subsequent functional enrichment analyses of the identified protein candidates indicated their involvement in regulating cellular metabolism, apoptosis, programmed cell death, lymphocyte-mediated immunity, and defense response pathways in RRMM. The top protein candidate SERPINB9 was confirmed by PRM analysis and western blotting as well as by comparison with an NCBI GEO dataset. We elucidated the proteome landscape of bortezomib-resistant RRMM and identified SERPINB9 as a promising novel therapeutic target. Our results provide a resource for future studies on the mechanism of RRMM.

Cyclopamine sensitizes multiple myeloma cells to circularly permuted TRAIL-induced apoptosis

Tumor necrosis factor related apoptosis inducing ligand (TRAIL) is a promising anti-myeloma drug prototype. The aim of the present study was to investigate the synergistic effects of cyclopamine and circularly permuted TRAIL (CPT) on the proliferation and apoptosis of multiple myeloma cells. The results showed that the inhibitory effects of cyclopamine on the proliferation of human myeloma RPMI-8226 and SKO-007 cells were weak. RPMI-8226 cells were sensitive to CPT; however, the proliferation of SKO-007 cells was not effectively inhibited by CPT. SKO-007 cells were thus considered resistant to cyclopamine and CPT and used for subsequent experiments. Treatment with a combination of cyclopamine and CPT significantly inhibited cell proliferation. Moreover, the Q value showed that cyclopamine combined with CPT could synergistically inhibit the proliferation of SKO-007 cells. Cyclopamine increased CPT-induced apoptosis in the SKO-007 cells and exhibited a synergistic induction of apoptosis when combined with CPT. Moreover, the combination of cyclopamine and CPT decreased the ratio of myeloma stem cells. Quantitative PCR showed that cyclopamine decreased the mRNA expression levels of GLI1/GLI2/GLI3 and increased the expression levels of death receptor 4. In conclusion, the present study showed that a combination of cyclopamine and CPT exhibited synergistic effects on the inhibition of proliferation and induction of apoptosis in myeloma cells.

Targeting NSD2-mediated SRC-3 liquid-liquid phase separation sensitizes bortezomib treatment in multiple myeloma

Development of chemoresistance is the main reason for failure of clinical management of multiple myeloma (MM), but the genetic and epigenetic aberrations that interact to confer such chemoresistance remains unknown. In the present study, we find that high steroid receptor coactivator-3 (SRC-3) expression is correlated with relapse/refractory and poor outcomes in MM patients treated with bortezomib (BTZ)-based regimens. Furthermore, in immortalized cell lines, high SRC-3 enhances resistance to proteasome inhibitor (PI)-induced apoptosis. Overexpressed histone methyltransferase NSD2 in patients bearing a t(4;14) translocation or in BTZ-resistant MM cells coordinates elevated SRC-3 by enhancing its liquid–liquid phase separation to supranormally modify histone H3 lysine 36 dimethylation (H3K36me2) modifications on promoters of anti-apoptotic genes. Targeting SRC-3 or interference of its interactions with NSD2 using a newly developed inhibitor, SI-2, sensitizes BTZ treatment and overcomes drug resistance both in vitro and in vivo. Taken together, our findings elucidate a previously unrecognized orchestration of SRC-3 and NSD2 in acquired drug resistance of MM and suggest that SI-2 may be efficacious for overcoming drug resistance in MM patients.

The mechanisms behind acquired resistance to the proteasome inhibitor bortezomib in multiple myeloma remain to be elucidated. Here, the authors show that the histone methyltransferase NSD2 stabilized SRC-3 protein levels, promotes its phase separation and alters H3K36me2 at certain gene promoters resulting in a transcriptional profile that favors resistance of myeloma cells to bortezomib.

Anti-tumor activities of the new oral pan-RAF inhibitor, TAK-580, used as monotherapy or in combination with novel agents in multiple myeloma

Many RAS pathway inhibitors, including pan-RAF inhibitors, have shown significant anti-tumor activities in both solid and hematological tumors. The pan-RAF inhibitor, TAK-580, is a representative of the novel RAF inhibitors that act by disrupting RAF homo- or heterodimerization. In this study, we examined the anti-tumor effects of TAK-580 used as monotherapy or in combination with bortezomib, lenalidomide, or other novel agents in multiple myeloma (MM) cells in vitro. TAK-580 monotherapy potently targeted proteins in the RAS-RAF-MEK-ERK signaling pathway and induced potent cytotoxicity and apoptosis in MM cell lines and myeloma cells from patients with newly diagnosed and relapsed and/or refractory MM, compared with a representative RAF inhibitor, dabrafenib. Normal donor peripheral blood B lymphocytes and cord blood CD34-positive cells were not affected. Importantly, TAK-580 significantly inhibited phospho-FOXO3 and induced upregulation of Bim_L and Bim_S in a dose-dependent manner, finally leading to apoptosis in MM cells. Moreover, TAK-580 enhanced bortezomib-induced cytotoxicity and apoptosis in MM cells via the FOXO3-Bim axis and the terminal unfolded protein response. Importantly, TAK-580 also enhanced lenalidomide-induced cytotoxicity and apoptosis in MM cells. Taken together, our results provide the rationale for TAK-580 monotherapy and/or treatment in combination with novel agents to improve outcomes in patients with MM.

Design, synthesis and biological evaluation of thioether-containing lenalidomide and pomalidomide derivatives with anti-multiple myeloma activity

Lenalidomide and its analogs are well-known for treating multiple myeloma. In this work, designed sulfide-modified lenalidomide and pomalidomide were synthesized and evaluated. The anti-proliferative activity against MM.1S cell line of 3ak (IC₅₀ = 79 nM) was similar to lenalidomide (IC₅₀ = 81 nM). Compared to benzylic thioether substituted lenalidomide 3a, the half-live (T_1/2) of 4-F-phenyl-thioether analogs 3ak in human liver microsomes was promoted from 3 min to 416.7 min. The corresponding metabolic factor of 3ak was increased from 2.8% to 79.5%, which was slightly lower than lenalidomide (91.5%). Moreover, the IKZF1 degradation of 3y and 3ak was well related with corresponding IC₅₀ values, which suggested the IKZF1 degradation efficiency is correlated to the responses of MM1. S cells. Furthermore, the oral administration of compounds 3y and 3ak at dosages of 60 mg/kg could delay tumor growth in female CB-17 SCID mice. This research helped to prompt the stability of thioether lenalidomide analogs, which paved the way for developing better molecules for treating multiple myeloma.

CircRNA ITCH increases bortezomib sensitivity through regulating the miR-615-3p/PRKCD axis in multiple myeloma

AIMS

Bortezomib (BTZ) is described as the first-line agent for multiple myeloma (MM) chemotherapy, but the emergence of BTZ resistance usually results in the failure of chemotherapy in MM. Circular RNA (circRNA) itchy E3 ubiquitin protein ligase (circITCH) is a novel identified circRNA that plays a vital role in the development of human cancers. However, the role of circITCH in the development of BTZ resistance in MM remains elusive.

MATERIALS AND METHODS

The expression of circITCH, miR-615-3p, and protein kinase C, delta (PRKCD) was detected with quantitative reverse transcription PCR and western blot. The effects of circITCH on the sensitivity of MM cells to BTZ were assessed using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay, flow cytometry, and xenograft tumor assay. The interaction of circITCH, microRNA-615-3p, and PRKCD was explored using luciferase reporter assay and RNA immunoprecipitation assay.

KEY FINDINGS

circITCH was downregulated in MM bone marrow specimens and cell lines, as well as BTZ-resistant MM cells. Reduced expression of circITCH was indicative of poor prognosis in MM patients. Upregulation of circITCH enhanced the sensitivity of BTZ-resistant MM cells to BTZ in vitro and in vivo. Furthermore, circITCH was identified as a sponge for miR-615-3p, and PRKCD is confirmed as a direct target of miR-615-3p. Besides, circITCH overexpression enhanced the sensitivity of MM cells to BTZ through miR-615-3p/PRKCD axis.

SIGNIFICANCE

circITCH overexpression enhanced the sensitivity of MM cells to BTZ through miR-615-3p/PRKCD axis, providing a novel potential target for combating BTZ resistance in patients with MM.

Circulating miR-451a levels as a potential biomarker to predict the prognosis of patients with multiple myeloma

The natural course of multiple myeloma (MM) varies greatly between patients. The Revised MM International Staging System (R-ISS) identifies high-risk patients, but it is unsuitable for assessing minimal residual disease (MRD). Furthermore, the focal location of myeloma cells and clonal evolution often produce false negative results in flow cytometry. Extracellular microRNA (miRNA/miR) expression levels are stable in bodily fluids, and are retrievable and measurable from fresh or archived serum or plasma samples. Therefore, the present study aimed to investigate the clinical utility of circulating miRNA levels in patients with MM, particularly miR-451a, which is commonly downregulated in MM, and whether it could predict the prognosis and relapse of patients with MM. In total, 66 patients with MM, stratified using the R-ISS criteria, were recruited, while 10 healthy subjects (transplantation donors) were enrolled as controls. Reverse transcription-quantitative PCR was used to evaluate miR-451a expression in bone marrow (BM) and in the circulation. IL-6 levels were measured using ELISA, while western blotting was conducted to analyze the protein expression levels of the IL-6 receptor (IL-6R). During follow-up, MRD was assessed via multiparameter flow cytometry (MFC). miR-451a was identified to target IL-6R using a dual-luciferase reporter assay. Circulating miR-451a levels were low in patients with MM, and was found to be 0.39 times that of the control group (U=4.00; P<0.001). Among the 66 patients with MM, the median level of miR-451a was 0.73 and 0.41 times that of the control group in R-ISS stage I MM (15 patients) and R-ISS stage II stage (17 patients), respectively; patients with R-ISS stage III MM (34 patients) had the lowest level, at 0.24 times the value of the control group. Circulating miR-451a levels had a strong positive correlation with miR-451a levels in BM, but negatively correlated with IL-6 and IL-6R levels. After two courses of consolidation chemotherapy, 19 patients achieved complete remission, 10 of whom presented steady circulating miR-451a levels during follow-up; the other nine patients had an abrupt decrease in circulating miR-451a levels. The turning points in the trend appeared 4–8 weeks before positive results were obtained via MFC, and 4–16 weeks before clinical relapse. Moreover, miR-451a overexpression notably downregulated the expression of the IL-6R mRNA and protein. Collectively, circulating miR-451a levels potentially represent a novel biomarker to monitor MRD and predict relapse.

Understanding Mesangial Pathobiology in AL-Amyloidosis and Monoclonal Ig Light Chain Deposition Disease

Patients with plasma cell dyscrasias produce free abnormal monoclonal Ig light chains that circulate in the blood stream. Some of them, termed glomerulopathic light chains, interact with the mesangial cells and trigger, in a manner dependent of their structural and physicochemical properties, a sequence of pathological events that results in either light chain–derived (AL) amyloidosis (AL-Am) or light chain deposition disease (LCDD). The mesangial cells play a key role in the pathogenesis of both diseases. The interaction with the pathogenic light chain elicits specific cellular processes, which include apoptosis, phenotype transformation, and secretion of extracellular matrix components and metalloproteinases. Monoclonal light chains associated with AL-Am but not those producing LCDD are avidly endocytosed by mesangial cells and delivered to the mature lysosomal compartment where amyloid fibrils are formed. Light chains from patients with LCDD exert their pathogenic signaling effect at the cell surface of mesangial cells. These events are generic mesangial responses to a variety of adverse stimuli, and they are similar to those characterizing other more frequent glomerulopathies responsible for many cases of end-stage renal disease. The pathophysiologic events that have been elucidated allow to propose future therapeutic approaches aimed at preventing, stopping, ameliorating, or reversing the adverse effects resulting from the interactions between glomerulopathic light chains and mesangium.

A comparative effectiveness study of lipegfilgrastim in multiple myeloma patients after high dose melphalan and autologous stem cell transplant

G-CSF administration after high-dose chemotherapy and autologous stem cell transplantation (ASCT) has been shown to expedite neutrophil recovery. Several studies comparing filgrastim and pegfilgrastim in the post-ASCT setting concluded that the two are at least equally effective. Lipegfilgrastim (LIP) is a new long-acting, once-per-cycle G-CSF. This multicentric, prospective study aimed to describe the use of LIP in multiple myeloma patients receiving high-dose melphalan and autologous stem cell transplantation (ASCT) and compare LIP with historic controls of patients who received short-acting agent (filgrastim [FIL]). Overall, 125 patients with a median age of 60 years received G-CSF after ASCT (80 patients LIP on day 1 post-ASCT and 45 patients FIL on day 5 post-ASCT). The median duration of grade 4 neutropenia (absolute neutrophil count [ANC] < 0.5 × 10 [9]/L) was 5 days in both LIP and FIL groups, whereas the median number of days to reach ANC ≥ 0.5 × 10 [9]/L was 10% lower in the LIP than in the FIL group (10 vs 11 days), respectively. Male sex was significantly associated with a faster ANC ≥ 0.5 × 10 [9] L response (p = 0.015). The incidence of FN was significantly lower in the LIP than in the FIL group (29% vs 49%, respectively, p = 0.024). The days to discharge after ASCT infusion were greater in patients with FN (p < 0.001). The study indicates that LIP had a shorter time to ANC recovery and is more effective than FIL for the prevention of FN in the ASCT setting.

Silencing RRM2 inhibits multiple myeloma by targeting the Wnt/β‑catenin signaling pathway

Ribonucleotide reductase M2 (RRM2) is one of the two subunits that comprise ribonucleotide reductase (RR), the enzyme that catalyzes the conversion of ribonucleotide 5'‑diphosphates into 2'‑deoxyribonucleotides, which are required for DNA synthesis. RRM2 is a stress response factor important for the development of several tumors. However, its role in multiple myeloma (MM) remains to be fully elucidated. The present study aimed to investigate the role of RRM2 in MM. The expression of RRM2 in patients with MM was analyzed using the Oncomine database. The results demonstrated that RRM2 expression was higher in MM compared with healthy subjects. Reverse transcription‑quantitative polymerase chain reaction and western blot results revealed that RRM2 expression was decreased following transfection with a small interfering RNA targeting RRM2 into NCI‑H929 cells. RR activity and Cell Counting Kit‑8 assays demonstrated that RRM2 silencing reduced RR activity and inhibited cell proliferation. Annexin V‑propidium iodide staining indicated that the percentage of apoptotic NCI‑H929 cells was increased following RRM2 silencing compared with that in the control group. Increased phosphorylation of H2AX indicated that RRM2 silencing may activate the DNA‑damage response pathway in NCI‑H929 cells. Western blot analysis revealed that protein levels of the apoptosis‑associated factor Bcl‑2 were reduced, whereas Bax, cleaved caspase‑3 and cleaved poly(ADP‑ribose) polymerase 1 were upregulated following RRM2 silencing compared with the control group. In addition, the results demonstrated that RRM2 silencing may inhibit target gene expression in the Wnt/β‑catenin signaling pathway by increasing the phosphorylation of glucose synthase kinase 3β. These findings indicated that RRM2 may be involved in the proliferation and apoptosis of MM cells via the Wnt/β‑catenin signaling pathway, suggesting that RRM2 may represent a novel therapeutic target for MM.