scholarly journals BCL2 Family Inhibitors in the Biology and Treatment of Multiple Myeloma

2021 ◽  
Vol Volume 11 ◽  
pp. 11-24
Author(s):  
Vikas A Gupta ◽  
James Ackley ◽  
Jonathan L Kaufman ◽  
Lawrence H Boise
Keyword(s):  
Multiple Myeloma ◽  
Bcl2 Family

scholarly journals Hierarchy for targeting prosurvival BCL2 family proteins in multiple myeloma: pivotal role of MCL1

Blood ◽  
2016 ◽  
Vol 128 (14) ◽  
pp. 1834-1844 ◽  
Author(s):  
Jia-Nan Gong ◽  
Tiffany Khong ◽  
David Segal ◽  
Yuan Yao ◽  
Chris D. Riffkin ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Cell Lines ◽  
Myeloma Cell ◽  
Pivotal Role ◽  
Bcl2 Family ◽  
Key Points ◽  
Low Passage ◽  
Bh3 Mimetic

Key Points Only a minority of myeloma cell lines are killed when the prosurvival BCL2 or BCLXL are selectively inhibited with BH3 mimetic compounds. In contrast, targeting MCL1 readily killed ∼70% of the myeloma cell lines tested, including both low-passage and well-established ones.

Abstract 972: Targeting glucose and glutamine regulated BCL2 family members for multiple myeloma therapy

2015 ◽  
Author(s):  
Richa Bajpai ◽  
Shannon M. Matulis ◽  
Changyong Wei ◽  
Ajay K. Nooka ◽  
Lawrence H. Boise ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Family Members ◽  
Bcl2 Family

scholarly journals Overcoming Resistance to Apoptosis in Multiple Myeloma By Simultaneous Inhibition of Bcl2 and IAP Families of Anti-Apoptotic Proteins

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 2088-2088
Author(s):  
Marcus Gomez ◽  
Vijay G. Ramakrishnan ◽  
Vivek Prasad ◽  
Teresa K. Kimlinger ◽  
Utkarsh Painuly ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
Cell Death ◽  
Er Stress ◽  
Cell Lines ◽  
Bcl2 Family ◽  
Er Stress Response ◽  
Simultaneous Inhibition ◽  
Apoptotic Proteins ◽  
Upr Pathway

Abstract Background: Multiple myeloma (MM) cells evade apoptosis through multiple mechanisms thus enabling it to evade therapy. The Bcl2 family of anti-apoptotic proteins is aberrantly expressed in MM cell lines and patient cells. Yet, pharmacological intervention of this family appears to have significant activity only in molecular subgroups of MM patients. This clearly suggests alternate mechanisms of overcoming apoptotic signals in MM cells in addition to the Bcl2 family, through proteins such as IAPs. We have previously shown that simultaneous inhibition of the three major IAP proteins, namely cIAP1, cIAP2 and XIAP is required to induce pronounced apoptosis in MM cells. However, IAP inhibition results in apoptosis in only some MM cell lines and patient cells. Given that levels of Bcl2 family proteins are unaffected by IAP inhibition, we hypothesized that combined inhibition of the IAP proteins using a SMAC mimetic LCL161 and the Bcl2 family proteins using a pan-Bcl2 inhibitor obatoclax (OBX) will lead to more pronounced and synergistic cell death in a broader subgroup of MM patients. Methods: LCL161 was synthesized by Novartis Inc. (Basel, Switzerland). OBX was purchased from Selleckchem (Houston, USA). Stock solutions were made in DMSO, and subsequently diluted in RPMI-1640 medium for use. MM cell lines were cultured in RPMI 1640 containing 10% fetal bovine serum (20% serum for primary patient cells) supplemented with L-Glutamine, penicillin, and streptomycin. Cytotoxicity was measured using the MTT viability assay and proliferation using thymidine uptake. Apoptosis was measured using flow cytometry upon cell staining with Annexin V-FITC and propidium iodide (PI) for cell lines and patient cells. Immunoblotting was done on cell extracts at various time points following incubation with the drugs in order to study the cell signaling pathways and a Results: LCL161/OBX combination induced synergistic cytotoxicity and anti-proliferative effects on a broad range of human MM cell lines, including drug resistant cell lines like DOX40 and MM1R. Components of the bone marrow microenvironment including bone marrow stromal cells and tumor promoting cytokines (VEGF, IGF and IL6) were unable to protect MM cells from the effects of the drug combination. We saw a time dependent increase in apoptosis, with the combination inducing significantly more apoptosis than either of the single agents alone. Examining the mechanism of action of the drug combination showed clear inhibition of the IAP proteins, activation of caspases 9, 8, 3 and Bid by LCL161 and the combination and up regulation of the pro-apoptotic proteins Bim, Bid, Puma and Noxa and accumulation of LC3-II by OBX and the combination. Using chloroquine along with the OBX, we were able to demonstrate that OBX induced protective autophagy and the addition of LCL161 was able to overcome this protective effect induced after single agent OBX treatment. Since protective autophagy can be induced by the ER stress response, we then examined the expression levels of proteins involved in this pathway. We observed clear induction of ER stress mediated UPR pathway by both the drugs. However, LCL161 and OBX induced different branches of the UPR pathway. OBX activated the ATF6 and pErk/peif2α/ATF4 branches of the UPR, both of which have been implicated in cell survival during ER stress. ATF4 under irrecoverable ER stress can lead to increase in transcription of CHOP and cause apoptosis. We therefore examined levels of CHOP and observed no induction of CHOP post treatment with either of the drugs or the combination. LCL161, however differentially modulated the IRE1 branch of the UPR by down regulating Xbp-1 splicing, which is a pro survival activity of IREI and up regulating pJNK, which indicated a pro-apoptotic activity induced by IRE1 post irrecoverable ER stress This indicated that the ER stress induced apoptosis is triggered by LCL161, which might be important to overcome the ER induced protective effects induced by OBX. Conclusion: Taken together, our studies indicate that LCL161/OBX combination induces synergistic cell death through modulation of apoptosis, authophagy and the ER stress response. Disclosures No relevant conflicts of interest to declare.

scholarly journals The proteasome deubiquitinase inhibitor VLX1570 shows selectivity for ubiquitin-specific protease-14 and induces apoptosis of multiple myeloma cells

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Xin Wang ◽  
Magdalena Mazurkiewicz ◽  
Ellin-Kristina Hillert ◽  
Maria Hägg Olofsson ◽  
Stefan Pierrou ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Drug Uptake ◽  
Myeloma Cells ◽  
Bcl2 Family ◽  
Promising Strategy ◽  
Specific Protease ◽  
Xenograft Models ◽  
Ubiquitin Specific Protease ◽  
Extended Survival

Abstract Inhibition of deubiquitinase (DUB) activity is a promising strategy for cancer therapy. VLX1570 is an inhibitor of proteasome DUB activity currently in clinical trials for relapsed multiple myeloma. Here we show that VLX1570 binds to and inhibits the activity of ubiquitin-specific protease-14 (USP14) in vitro, with comparatively weaker inhibitory activity towards UCHL5 (ubiquitin-C-terminal hydrolase-5). Exposure of multiple myeloma cells to VLX1570 resulted in thermostabilization of USP14 at therapeutically relevant concentrations. Transient knockdown of USP14 or UCHL5 expression by electroporation of siRNA reduced the viability of multiple myeloma cells. Treatment of multiple myeloma cells with VLX1570 induced the accumulation of proteasome-bound high molecular weight polyubiquitin conjugates and an apoptotic response. Sensitivity to VLX1570 was moderately affected by altered drug uptake, but was unaffected by overexpression of BCL2-family proteins or inhibitors of caspase activity. Finally, treatment with VLX1570 was found to lead to extended survival in xenograft models of multiple myeloma. Our findings demonstrate promising antiproliferative activity of VLX1570 in multiple myeloma, primarily associated with inhibition of USP14 activity.

scholarly journals Overcoming MCL1 Resistance in Multiple Myeloma

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 472-472
Author(s):  
Ka Tat Siu ◽  
Cherrie Huang ◽  
Cristina Panaroni ◽  
Kenta Mukaihara ◽  
Keertik Fulzele ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Growth Factors ◽  
Cell Growth ◽  
Cell Viability ◽  
Cell Lines ◽  
Cytotoxic Effect ◽  
Combined Therapy ◽  
Intrinsic Apoptotic Pathway ◽  
Apoptotic Pathway ◽  
Bcl2 Family

Abstract Disruption of the intrinsic apoptotic pathway by the aberrant expression of the BCL2 family members are frequent events in multiple myeloma (MM). The anti-apoptotic protein myeloid cell leukemia-1 (MCL1) is highly expressed in MM and plays a crucial role in disease progression. Inhibition of MCL1, thus, represents a unique therapeutic opportunity for the control of the disease. Currently, there is no FDA-approved drug with the ability to selectively target MCL1. Because of its pivotal role in MM, MCL1 is considered a high-value therapeutic target in the clinic. In this report, we use a selective small-molecule inhibitor of MCL1, AZD5991, to examine the therapeutic consequences of MCL1 inhibition in MM. AZD5991 treatment resulted in dose-dependent cytotoxicity with EC50 values ranging from 64 and 417 nM at 24 hours for MCL1-sensitive cell lines (H929, MM.1S, RPMI-8226, U266, LP-1 and ANBL6VR). Two cell lines DOX40 and KMS-12-PE remained resistant to MCL1 inhibition. For the MCL1-sensitive MM.1S and H929 cells, the decrease in cell viability upon MCL1 inhibition was due to an increase in apoptosis. AZD5991 treatment led to 40-82% decrease in viability of CD138+ cells isolated from relapsed and refractory MM patients at a dose of 300 nM at 24 hours. These results indicate that AZD5991 has promising single-agent activity, but it would be prudent to study it in combination with other anti-MM therapies. The BM microenvironment enhances tumor cell growth and survival in MM. We found that soluble factors produced during the MM-BMSC interaction reduced the sensitivity of MM cells to AZD5991, and direct MM-BMSC contact blunted the cytotoxic effect of AZD5991. A comprehensive cytokine array analysis revealed an enrichment of a panel of pro-survival cytokines and growth factors, with the cytokines IL-6, IL-8 and GROα/β/γ being among the most highly up-regulated proteins, upon cell-cell contact between MM.1S cells and BMSCs. Enrichment of these cytokines in the BM milieu, at least in part, confer a protective effect on MM cells and endow them with the ability to resist MCL1 inhibition. A shift in the balance of BCL2 family members is often the primary reason for drug resistance. We found that the baseline BCL2 mRNA expression and the BCL2:MCL1 ratios in the MM cell lines examined are negatively correlated to their corresponding sensitivity to AZD5991. In other words, MM cells with a high BCL2 reservoir are more likely to circumvent cell death elicited by MCL1 inhibition. Treatment with AZD5991 alone leads to release of Bim from MCL1 and an increased Bim bound to BCL2. Venetoclax, a BH3 mimetic that selectively binds BCL2, treatment alone releases Bim from BCL2 and results in an increased Bim bound to MCL1. Bim binding to MCL1 and BCL2 was significantly diminished upon co-treatment. The free-floating Bim proteins subsequently activate the intrinsic apoptotic pathway by facilitating cytochrome c release. These results suggested that MM cells switch their survival dependency to BCL2 upon MCL1 inhibition, and that BCL2 blockade could be an effective way to overcome MCL1 resistance in MM. Based on these observations, we combined AZD5991 with Venetoclax in MM cells. A significant decrease in cell viability was observed with the combined therapy compared with both drugs used alone. Isobologram analysis confirmed greater than additive or synergistic effect upon co-treatment. The enhanced cytotoxic effect of the combined therapy retains even when the MM cells are in co-culture with BMSCs. Remarkably, the pro-survival cytokines IL-6, IL-8 and GROα/β/γ, which were expressed at high levels in the co-culture settings, were among the ones being most reduced after the combined therapy. Our results demonstrated that the combined AZD5991/Venetoclax therapy overcomes the inherent MCL1-resistance in MM via two independent mechanisms. First, the concomitant suppression of the anti-apoptotic proteins MCL1 and BCL2 prevent MM cells from escaping apoptosis by releasing Bim to trigger mitochondrial outer membrane potential and the subsequent release of cytochrome c to activate the intrinsic apoptotic pathway. Second, this combined therapy prevents MM cell growth by causing down-regulation of pro-survival cytokines and growth factors in the BM microenvironment. As a proof of concept, our data indicate combining therapeutics that selectively target the anti-apoptotic proteins MCL1 and BCL2 could be an effective therapy for MM patients. Disclosures Cidado: AstraZeneca: Employment, Equity Ownership. Drew:AstraZeneca: Employment.

scholarly journals Apoptosis reprogramming triggered by splicing inhibitors sensitizes multiple myeloma cells to Venetoclax treatment

Haematologica ◽  
2021 ◽  
Author(s):  
Debora Soncini ◽  
Claudia Martinuzzi ◽  
Pamela Becherini ◽  
Elisa Gelli ◽  
Samantha Ruberti ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Plasma Cells ◽  
Myeloid Cell ◽  
Growth And Survival ◽  
Bcl2 Family ◽  
Cell Growth And Viability ◽  
Novel Therapeutic Strategies ◽  
The Impact

Identification of novel vulnerabilities in the context of therapeutic resistance is emerging as key challenge for cancer treatment. Recent studies have detected pervasive aberrant splicing in cancer cells, supporting its targeting for novel therapeutic strategies. Here, we evaluated the expression of several spliceosome machinery components in multiple myeloma (MM) cells and the impact of splicing modulation on tumor cell growth and viability. A comprehensive gene expression analysis confirmed the reported deregulation of spliceosome machinery components in MM cells, compared to normal plasma cells (PCs) from healthy donors, with its pharmacological and genetic modulation resulting in impaired growth and survival of MM cell lines and patient-derived malignant PCs. Consistent with this, transcriptomic analysis revealed deregulation of BCL2 family members, including decrease of antiapoptotic long form of myeloid cell leukemia-1 (MCL1) expression, as crucial for “priming” MM cells for Venetoclax activity in vitro and in vivo, irrespective of t(11;14) status. Overall, our data provide a rationale for supporting the clinical use of splicing modulators as a strategy to reprogram apoptotic dependencies and make all MM patients more vulnerable to BCL2 inhibitors.

B-Cell Markers Predict Response to Venetoclax in Multiple Myeloma

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 2108-2108 ◽  
Author(s):  
Vikas A. Gupta ◽  
Scott Newman ◽  
Nizar J. Bahlis ◽  
Jonathan J Keats ◽  
Shannon Matulis ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
B Cells ◽  
B Cell ◽  
Cell Lines ◽  
Research Funding ◽  
Plasma Cells ◽  
Gene Signature ◽  
Myeloma Cell ◽  
Bcl2 Family

Abstract BCL2 family members such as MCL1, BCLXL, and BCL2 are critical for cancer cell survival and therefore represent promising therapeutic targets. Both B cells and CLL cells depend primarily on BCL-2 and are thus sensitive to the BCL2 specific inhibitor venetoclax, while plasma cells and multiple myeloma typically depend on Mcl-1 and would therefore be resistant to venetoclax. However, a subset of myeloma is venetoclax sensitive based on recent in vitro and clinical trial data. In preliminary results from a phase I trial of venetoclax in multiple myeloma, 40% of patients positive for t(11;14) had objective responses, while only 6% of t(11;14) negative patients responded. We have made similar observations with in vitro testing of 30 freshly isolated myeloma patient samples, identifying both non-t(11;14) samples sensitive to venetoclax as well as resistant t(11;14) positive samples. Together, these results suggest not only that a subset of multiple myeloma is co-dependent on BCL2 but also that t(11;14) is neither necessary nor sufficient for responding to venetoclax. We therefore set out to identify other factors that may predict BCL2 dependence in multiple myeloma. Previous studies of t(11;14) myeloma have noted increased expression of CD20, CD23, CD79a, and PAX5 which are typically associated with B cells prior to their differentiation into plasma cells. Based on these observations we hypothesized that venetoclax sensitivity in myeloma may be associated with the retention of B cell properties including BCL2 dependence. We probed an online expression database of myeloma cell lines for non-t(11;14) cell lines expressing CD20 and identified two cell lines, OCI-My5 and PCM6, both of which we found to have an IC50 of approximately 50nM when treated with venetoclax. We went on to characterize a panel of 13 cell lines. In addition to OCI-My5 and PCM6, 4 other cell lines were sensitive to venetoclax, all positive for t(11;14). Of the 7 venetoclax resistant cell lines, 2 were t(11;14) positive. Protein levels of MCL1, BCLXL, and BCL2 were comparable among the 13 lines and therefore anti-apoptotic expression is unlikely to be responsible for venetoclax sensitivity. Consistent with our previous co-immunoprecipitation studies, more of the pro-apoptotic BIM was bound to BCL2 in venetoclax sensitive lines compared to resistant lines. In the absence of differences in BCL2 family expression, we next sought to identify other B cell related features correlating with venetoclax sensitivity. We used RNAseq data from our 13 cell lines to compare the expression of 100 genes previously reported to be differentially expressed between normal B cells and plasma cells. Interestingly, unsupervised clustering revealed a group of venetoclax sensitive cells enriched for other B cell associated genes. GSEA revealed enrichment of genes associated with immune system activation at a p < 0.001. We also analyzed the differential expression of genes between our sensitive and resistant lines and again identified overexpression of B cell related genes such as CD20, CD79A, STAT5A, and RASGRP2 in venetoclax sensitive lines, though no single marker was present in all of the venetoclax sensitive lines. We examined the expression of CD20, CD79a, and CD79b in the CoMMpass data set (IA8) as well and found that they were not co-expressed in most patients, again suggesting that no single marker is likely to be predictive. Finally, we created a gene signature from the top differentially expressed genes to predict sensitivity or resistance to venetoclax and used this signature to evaluate a database of 68 myeloma cell lines. One of the top hits predicted to be sensitive by our gene signature is the t(11;14) negative line MOLP2, and indeed this cell line was recently reported to be highly responsive to venetoclax. In conclusion, B cell markers and our gene signature correlate with BCL2 dependence and venetoclax sensitivity independent of t(11;14). Disclosures Bahlis: BMS: Honoraria; Onyx: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Other: Travel Expenses, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Other: Travel Expenses, Research Funding, Speakers Bureau; Amgen: Consultancy, Honoraria. Nooka:Spectrum, Novartis, Onyx pharmaceuticals: Consultancy. Kaufman:Pharmacyclics: Consultancy; Incyte: Consultancy; Novartis: Consultancy, Research Funding; Celgene: Consultancy, Research Funding. Lonial:Onyx: Consultancy; Onyx: Consultancy; BMS: Consultancy; Janssen: Consultancy; Merck: Consultancy; Celgene: Consultancy; Novartis: Consultancy; Millenium: Consultancy; BMS: Consultancy; Celgene: Consultancy; Novartis: Consultancy; Janssen: Consultancy.

Proteasome inhibitors as therapeutics

2005 ◽  
Vol 41 ◽  
pp. 205-218
Author(s):  
Constantine S. Mitsiades ◽  
Nicholas Mitsiades ◽  
Teru Hideshima ◽  
Paul G. Richardson ◽  
Kenneth C. Anderson
Keyword(s):  
Multiple Myeloma ◽  
Drug Class ◽  
Proteasome Inhibitors ◽  
Cell Cycle Regulators ◽  
Current State ◽  
Intracellular Mechanism ◽  
Ubiquitin Proteasome ◽  
Proteasome Pathway ◽  
Hodgkin's Lymphomas ◽  
Clinical Research Data

The ubiquitin–proteasome pathway is a principle intracellular mechanism for controlled protein degradation and has recently emerged as an attractive target for anticancer therapies, because of the pleiotropic cell-cycle regulators and modulators of apoptosis that are controlled by proteasome function. In this chapter, we review the current state of the field of proteasome inhibitors and their prototypic member, bortezomib, which was recently approved by the U.S. Food and Drug Administration for the treatment of advanced multiple myeloma. Particular emphasis is placed on the pre-clinical research data that became the basis for eventual clinical applications of proteasome inhibitors, an overview of the clinical development of this exciting drug class in multiple myeloma, and a appraisal of possible uses in other haematological malignancies, such non-Hodgkin's lymphomas.

Bone sialoprotein mRNA and protein expression in human multiple myeloma cell lines and patients

2000 ◽  
Vol 111 (4) ◽  
pp. 1118-1121 ◽  
Author(s):  
A. Bellahcene ◽  
I. Van Riet ◽  
C. de Greef ◽  
N. Antoine ◽  
M. F. Young ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Protein Expression ◽  
Cell Lines ◽  
Myeloma Cell ◽  
Bone Sialoprotein ◽  
Multiple Myeloma Cell ◽  
Human Multiple Myeloma ◽  
Mrna And Protein Expression
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