scholarly journals AHSA1 is a promising therapeutic target for cellular proliferation and proteasome inhibitor resistance in multiple myeloma

2022 ◽  
Vol 41 (1) ◽  
Author(s):  
Chunyan Gu ◽  
Yajun Wang ◽  
Lulin Zhang ◽  
Li Qiao ◽  
Shanliang Sun ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Therapeutic Target ◽  
Proteasome Inhibitor ◽  
Cellular Proliferation ◽  
Specific Binding ◽  
Xenograft Model ◽  
Site Mutation ◽  
Promising Therapeutic Target ◽  
Inhibitor Resistance

Abstract Background Currently, multiple myeloma (MM) is still an incurable plasma cell malignancy in urgent need of novel therapeutic targets and drugs. Methods Bufalin was known as a highly toxic but effective anti-cancer compound. We used Bufalin as a probe to screen its potential targets by proteome microarray, in which AHSA1 was the unique target of Bufalin. The effects of AHSA1 on cellular proliferation and drug resistance were determined by MTT, western blot, flow cytometry, immunohistochemistry staining and xenograft model in vivo. The potential mechanisms of Bufalin and KU-177 in AHSA1/HSP90 were verified by co-immunoprecipitation, mass spectrometry, site mutation and microscale thermophoresis assay. Results AHSA1 expression was increased in MM samples compared to normal controls, which was significantly associated with MM relapse and poor outcomes. Furthermore, AHSA1 promoted MM cell proliferation and proteasome inhibitor (PI) resistance in vitro and in vivo. Mechanism exploration indicated that AHSA1 acted as a co-chaperone of HSP90A to activate CDK6 and PSMD2, which were key regulators of MM proliferation and PI resistance respectively. Additionally, we identified AHSA1-K137 as the specific binding site of Bufalin on AHSA1, mutation of which decreased the interaction of AHSA1 with HSP90A and suppressed the function of AHSA1 on mediating CDK6 and PSMD2. Intriguingly, we discovered KU-177, an AHSA1 selective inhibitor, and found KU-177 targeting the same site as Bufalin. Bufalin and KU-177 treatments hampered the proliferation of flow MRD-positive cells in both primary MM and recurrent MM patient samples. Moreover, KU-177 abrogated the cellular proliferation and PI resistance induced by elevated AHSA1, and decreased the expression of CDK6 and PSMD2. Conclusions We demonstrate that AHSA1 may serve as a promising therapeutic target for cellular proliferation and proteasome inhibitor resistance in multiple myeloma.

Proteasome Maturation Protein (pomp) Is Associated With Proteasome Inhibitor Resistance In Myeloma, and Its Suppression Enhances The Activity Of Bortezomib and Carfilzomib

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 280-280 ◽  
Author(s):  
Bingzong Li ◽  
Hua Wang ◽  
Robert Z. Orlowski
Keyword(s):  
Multiple Myeloma ◽  
Cell Lines ◽  
Proteasome Inhibitor ◽  
Xenograft Model ◽  
Proteasome Inhibition ◽  
Over Expression ◽  
Murine Xenograft Model ◽  
Drug Naïve ◽  
Inhibitor Resistance ◽  
Rpmi 8226

Abstract Background Proteasome inhibition with bortezomib has revolutionized the treatment of multiple myeloma, but the vast majority of patients eventually develop clinical bortezomib resistance through poorly understood mechanisms. One of the most conserved cellular responses to proteasome inhibition is to up-regulate proteasome subunit expression, presumably with the goal of enhancing proteasome activity and restoring intracellular protein homeostasis. We therefore hypothesized that proteasome inhibitor resistance could be associated with enhanced proteasome assembly, and that suppression of this assembly process could help restore drug sensitivity. The current studies focused on POMP, which is involved in addition of catalytically active b subunits to the hemiproteasome ring initially formed by structural a subunits. Methods We studied ANBL-6, KAS-6/1, OPM-2, and RPMI 8226 multiple myeloma cell lines which had acquired bortezomib resistance through prolonged exposure to increasing drug concentrations, and compared them to their drug-naïve, vehicle-treated counterparts. In addition, we evaluated primary cells derived from patients with myeloma, and examined an in vivo murine xenograft model of human myeloma. Results Bortezomib-resistant (V10R) ANBL-6, KAS-6/1, OPM-2, and RPMI 8226 cell lines showed enhanced levels of POMP mRNA by quantitative (q) PCR compared to their drug-sensitive counterparts, which was associated with higher POMP protein levels seen by immunoblotting. Exogenous over-expression of POMP in drug-naïve OPM-2 and KAS-6/1 cells was sufficient by itself to induce resistance to both bortezomib and carfilzomib. Conversely, suppression of POMP with one of two different Lentiviral small hairpin (sh) RNAs restored sensitivity in OPM-2 and KAS-6/1 V10R cells to bortezomib and carfilzomib. Since no known pharmaceuticals directly target POMP, we examined its promoter region, and found a consensus binding site for nuclear factor (erythroid-derived 2)-like (NRF) 2. Consistent with a role of NRF2 in POMP expression, NRF2 mRNA and protein were increased in V10R myeloma cells, and in drug-naïve cells treated with bortezomib. Moreover, transfection of cells with NRF2 cDNA activated a POMP promoter reporter, while chromatin immunoprecipitation with anti-NRF2 antibodies preferentially precipitated sequences near the POMP promoter. Also, NRF2 over-expression induced POMP and enhanced proteasome chymotrypsin-like activity, while its suppression had the opposite effects. All trans-retinoic acid (ATRA) blocked nuclear accumulation of NRF2 in OPM-2 and KAS-6/1 V10R cells, and reduced expression of POMP. Combinations of bortezomib with ATRA showed enhanced activity against these drug-resistant cell lines in association with greater proteasome inhibition, and were synergistic in drug-naïve cells. In primary samples, ATRA with bortezomib induced a greater reduction in viability than did either treatment alone. Finally, in a murine xenograft model with OPM-2 V10R cells, neither ATRA nor bortezomib showed substantial activity, while the combination regimen, by comparison, retained efficacy. Conclusions Taken together, our data support the hypotheses that NRF-2-influenced POMP over-expression contributes to proteasome inhibitor resistance in multiple myeloma, while approaches targeting POMP hold promise in overcoming resistance. Moreover, they provide a framework for translation of proteasome inhibitors with ATRA to the clinic to enhance activity, and to overcome resistance to this important class of anti-myeloma agents. Disclosures: No relevant conflicts of interest to declare.

RFWD2 Induces Cellular Proliferation and Proteasome Inhibitor Resistance By Mediating p27 Ubiqutinaiton in Multiple Myeloma

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3068-3068
Author(s):  
Ye Yang ◽  
Mengjie Guo ◽  
Chunyan Gu
Keyword(s):  
Multiple Myeloma ◽  
Cell Proliferation ◽  
Drug Resistance ◽  
Proteasome Inhibitor ◽  
Cellular Proliferation ◽  
Conflicts Of Interest ◽  
Scid Mice ◽  
Rpmi 8226

Purpose: In recent years, with the emergence of targeted proteasome inhibitors (PIs), the treatment of multiple myeloma (MM) has made great progress and significantly improves the survival rate of patients. However, MM remains an incurable disease, mainly due to the recurrence of drug resistance. The constitutive photomorphogenic 1 (RFWD2, also known as COP1), is closely related to the occurrence and development of tumors, but its role in MM is largely unknown. This study was aimed to explore the mechanism of RFWD2 on cell proliferation and resistance to proteasome inhibitor in MM. Experimental Design: Using gene expression profiling (GEP) samples, we verified the relation of RFWD2 to MM patients' survival and drug-resistance. The effect of RFWD2 on cell proliferation was confirmed by MTT and cell cycle analysis in RFWD2-overexpressed and RFWD2-knockdown MM cells. MTT and apoptosis experiments were performed to evaluate whether RFWD2 influenced the sensitivity of MM cells to several chemotherapy drugs. MM xenografts were established in immunodeficient NOD/SCID mice by injecting wild-type or RFWD2 over-expression MM cells with drug intervention. The mechanism of drug resistance was elucidated by analyzing the association of RFWD2 with E3 ligase of p27. Bortezomib-resistant RPMI 8226 cells were used to construct RFWD2 knockdown cells, which were injected into NOD/SCID mice to assess the effect of RFWD2 on bortezomib resistance in vivo. Results: RFWD2 expression was closely related to poor outcome, relapse and bortezomib resistance in MM patients' GEP cohorts. Elevated RFWD2 induced cell proliferation, while decreased RFWD2 inhibited cell proliferation and induced apoptosis in MM cells. RFWD2-overexpression MM cells resulted in PIs resistance, however, no chemotherapy resistance to adriamycin and dexamethasone was observed in vitro. In addition, overexpressing RFWD2 in MM cells led to bortezomib resistance rather than adriamycin resistance in myeloma xenograft mouse model. RFWD2 regulated the ubiquitination degradation of P27 by interacting with RCHY1 ubiquitin ligase. The knockdown of RFWD2 in bortezomib-resistant RPMI 8226 cells overcame bortezomib resistance in vivo. Conclusions: Our data demonstrate that elevated RFWD2 induces MM cell proliferation and resistance to PIs, but not to adriamycin and dexamethasone both in vitro and in vivo through mediating the ubiquitination of p27. Collectively, RFWD2 is a novel promising therapeutic target in MM. Disclosures No relevant conflicts of interest to declare.

The Novel, Irreversible Proteasome Inhibitor PR-171 Demonstrates Potent Anti-Tumor Activity in Pre-Clinical Models of Multiple Myeloma, and Overcomes Bortezomib Resistance.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3461-3461
Author(s):  
Deborah J. Kuhn ◽  
Qing Chen ◽  
Peter M. Voorhees ◽  
John S. Strader ◽  
Kevin D. Shenk ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Proteasome Inhibitor ◽  
Caspase 3 ◽  
Cellular Proliferation ◽  
Myeloma Cell ◽  
Dominant Negative ◽  
Phase Iii ◽  
Multiple Myeloma Cell ◽  
Clinical Models

Abstract Introduction: The ubiquitin-proteasome pathway has been validated as a therapeutic target with the approval of the small molecule proteasome inhibitor, bortezomib (VELCADE®), in multiple myeloma and non-Hodgkin lymphoma. However, the overall response rate of patients with multiple myeloma in phase III clinical trials was 43%, underscoring the need for a next generation of inhibitors with the potential for greater efficacy. Methods: PR-171 is a novel, tetrapeptide epoxomicin-related inhibitor that binds the proteasome irreversibly, and our objectives were to evaluate its activity and mechanism of action in pre-clinical models of multiple myeloma. Results: PR-171 potently bound and inhibited the chymotrypsin-like subunit of the proteasome in vitro, in cellulo, and in vivo at low concentrations. At higher concentrations, however, unlike bortezomib, which targeted the chymotrypsin-like and peptidyl-glutamyl peptide hydrolyzing activities in vivo, PR-171 also displayed significant inhibition of the trypsin-like and the peptidyl-glutamyl peptide hydrolyzing activities. PR-171-induced proteasome inhibition was associated with accumulation of polyubiquitinated substrates and pro-apoptotic Bax. Brief pulse PR-171 exposure, which simulates the in vivo pharmacokinetics of bortezomib, led to PR-171-mediated inhibition of cellular proliferation linked to induction of caspase-3-dependent apoptosis through both intrinsic (caspase-9) and extrinsic (caspase-8-dependent) pathways. Pretreatment with caspase-3, -8, and -9 inhibitors rescued the anti-proliferative effect of PR-171. Furthermore, pulse PR-171 treatment activated c-Jun-N-terminal kinase, a key-signaling molecule in proteasome inhibitor-induced apoptosis, and cleavage of poly-ADP-ribose polymerase, while abrogation of c-Jun-N-terminal kinase signaling with a dominant-negative c-Jun inhibited PR-171-induced effects. PR-171 displayed enhanced anti-proliferative activity compared to bortezomib in multiple myeloma cell lines and freshly isolated patient-derived CD138+ plasma cells, associated with enhanced phosphorylation of c-Jun-N-terminal kinase and capase-3, -8, and -9 activation. Lastly, PR-171 was a potent inhibitor of proliferation in a multiple myeloma cell line model resistant to bortezomib and in isolates from two patients, one with primary and the other with acquired bortezomib-resistance. Conclusions: These data indicate that PR-171 has enhanced activity against preclinical models of multiple myeloma, perhaps owing to its irreversible binding and subunit specificity, and provide a rationale for its translation into the clinic.

scholarly journals SMAD1 as a biomarker and potential therapeutic target in drug-resistant multiple myeloma

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Jian Wu ◽  
Min Zhang ◽  
Omar Faruq ◽  
Eldad Zacksenhaus ◽  
Wenming Chen ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Drug Resistance ◽  
Therapeutic Target ◽  
Biological Activities ◽  
Xenograft Model ◽  
Myeloma Cell ◽  
Soft Agar ◽  
Drug Resistant ◽  
Migration Assay

Abstract Background SMAD1, a central mediator in TGF-β signaling, is involved in a broad range of biological activities including cell growth, apoptosis, development and immune response, and is implicated in diverse type of malignancies. Whether SMAD1 plays an important role in multiple myeloma (MM) pathogenesis and can serve as a therapeutic target are largely unknown. Methods Myeloma cell lines and primary MM samples were used. Cell culture, cytotoxicity and apoptosis assay, siRNA transfection, Western blot, RT-PCR, Soft-agar colony formation, and migration assay, Chromatin immunoprecipitation (Chip), animal xenograft model studies and statistical analysis were applied in this study. Results We demonstrate that SMAD1 is highly expressed in myeloma cells of MM patients with advanced stages or relapsed disease, and is associated with significantly shorter progression-free and overall survivals. Mechanistically, we show that SMAD1 is required for TGFβ-mediated proliferation in MM via an ID1/p21/p27 pathway. TGF-β also enhanced TNFα-Induced protein 8 (TNFAIP8) expression and inhibited apoptosis through SMAD1-mediated induction of NF-κB1. Accordingly, depletion of SMAD1 led to downregulation of NF-κB1 and TNFAIP8, resulting in caspase-8-induced apoptosis. In turn, inhibition of NF-κB1 suppressed SMAD1 and ID1 expression uncovering an autoregulatory loop. Dorsomorphin (DM), a SMAD1 inhibitor, exerted a dose-dependent cytotoxic effect on drug-resistant MM cells with minimal cytotoxicity to normal hematopoietic cells, and further synergized with the proteasomal-inhibitor bortezomib to effectively kill drug-resistant MM cells in vitro and in a myeloma xenograft model. Conclusions This study identifies SMAD1 regulation of NF-κB1/TNFAIP8 and ID1-p21/p27 as critical axes of MM drug resistance and provides a potentially new therapeutic strategy to treat drug resistance MM through targeted inhibition of SMAD1.

scholarly journals Anti-tumor activity of a novel proteasome inhibitor D395 against multiple myeloma and its lower cardiotoxicity compared with carfilzomib

2021 ◽  
Vol 12 (5) ◽  
Author(s):  
Xuxing Shen ◽  
Chao Wu ◽  
Meng Lei ◽  
Qing Yan ◽  
Haoyang Zhang ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Proteasome Inhibitor ◽  
Osteoclast Differentiation ◽  
Dependent Manner ◽  
Serum Enzyme ◽  
Herg Channels ◽  
Anti Tumor Activity ◽  
Dose Dependent

AbstractCarfilzomib, a second-generation proteasome inhibitor, has significantly improved the survival rate of multiple myeloma (MM) patients, but its clinical application is still restricted by drug resistance and cardiotoxicity. Here, we identified a novel proteasome inhibitor, D395, and assessed its efficacy in treating MM as well as its cardiotoxicity at the preclinical level. The activities of purified and intracellular proteasomes were measured to determine the effect of D395 on the proteasome. CCK-8 and flow cytometry experiments were designed to evaluate the effects of D395 on cell growth and apoptosis. The effects of D395 and carfilzomib on serum enzyme activity, echocardiography features, cardiomyocyte morphology, and hERG channels were also compared. In our study, D395 was highly cytotoxic to MM cell lines and primary MM cells but not normal cells, and it was well tolerated in vivo. Similar to carfilzomib, D395 inhibited osteoclast differentiation in a dose-dependent manner. In particular, D395 exhibited lower cardiotoxicity than carfilzomib in all experiments. In conclusion, D395 is a novel irreversible proteasome inhibitor that has remarkable anti-MM activity and mild cardiotoxicity in vitro and in vivo.

scholarly journals HNRNPA2B1 promotes multiple myeloma progression by increasing AKT3 expression via m6A-dependent stabilization of ILF3 mRNA

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Fengjie Jiang ◽  
Xiaozhu Tang ◽  
Chao Tang ◽  
Zhen Hua ◽  
Mengying Ke ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Cell Proliferation ◽  
Cellular Proliferation ◽  
Aberrant Expression ◽  
The Stability ◽  
Induced Apoptosis ◽  
Proliferation In Vitro

AbstractN6-methyladenosine (m6A) modification is the most prevalent modification in eukaryotic RNAs while accumulating studies suggest that m6A aberrant expression plays an important role in cancer. HNRNPA2B1 is a m6A reader which binds to nascent RNA and thus affects a perplexing array of RNA metabolism exquisitely. Despite unveiled facets that HNRNPA2B1 is deregulated in several tumors and facilitates tumor growth, a clear role of HNRNPA2B1 in multiple myeloma (MM) remains elusive. Herein, we analyzed the function and the regulatory mechanism of HNRNPA2B1 in MM. We found that HNRNPA2B1 was elevated in MM patients and negatively correlated with favorable prognosis. The depletion of HNRNPA2B1 in MM cells inhibited cell proliferation and induced apoptosis. On the contrary, the overexpression of HNRNPA2B1 promoted cell proliferation in vitro and in vivo. Mechanistic studies revealed that HNRNPA2B1 recognized the m6A sites of ILF3 and enhanced the stability of ILF3 mRNA transcripts, while AKT3 downregulation by siRNA abrogated the cellular proliferation induced by HNRNPA2B1 overexpression. Additionally, the expression of HNRNPA2B1, ILF3 and AKT3 was positively associated with each other in MM tissues tested by immunohistochemistry. In summary, our study highlights that HNRNPA2B1 potentially acts as a therapeutic target of MM through regulating AKT3 expression mediated by ILF3-dependent pattern.

scholarly journals A novel BCMA/CD3 bispecific T-cell engager for the treatment of multiple myeloma induces selective lysis in vitro and in vivo

Leukemia ◽  
2016 ◽  
Vol 31 (8) ◽  
pp. 1743-1751 ◽  
Author(s):  
S Hipp ◽  
Y-T Tai ◽  
D Blanset ◽  
P Deegen ◽  
J Wahl ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
T Cell ◽  
Plasma Cells ◽  
Ex Vivo ◽  
Xenograft Model ◽  
Selective Lysis ◽  
Bispecific T Cell Engager

Abstract B-cell maturation antigen (BCMA) is a highly plasma cell-selective protein that is expressed on malignant plasma cells of multiple myeloma (MM) patients and therefore is an ideal target for T-cell redirecting therapies. We developed a bispecific T-cell engager (BiTE) targeting BCMA and CD3ɛ (BI 836909) and studied its therapeutic impacts on MM. BI 836909 induced selective lysis of BCMA-positive MM cells, activation of T cells, release of cytokines and T-cell proliferation; whereas BCMA-negative cells were not affected. Activity of BI 836909 was not influenced by the presence of bone marrow stromal cells, soluble BCMA or a proliferation-inducing ligand (APRIL). In ex vivo assays, BI 836909 induced potent autologous MM cell lysis in both, newly diagnosed and relapsed/refractory patient samples. In mouse xenograft studies, BI 836909 induced tumor cell depletion in a subcutaneous NCI-H929 xenograft model and prolonged survival in an orthotopic L-363 xenograft model. In a cynomolgus monkey study, administration of BI 836909 led to depletion of BCMA-positive plasma cells in the bone marrow. Taken together, these results show that BI 836909 is a highly potent and efficacious approach to selectively deplete BCMA-positive MM cells and represents a novel immunotherapeutic for the treatment of MM.

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