Dexamethasone-induced cell death is restricted to specific molecular subgroups of multiple myeloma

The histone methyltransferase KMT2D maintains cellular glucocorticoid responsiveness by shielding the glucocorticoid receptor from degradation

Because of their ability to induce lymphocyte apoptosis, glucocorticoids (GC) are widely used to treat hematological malignancies such as lymphomas and multiple myeloma. Their effectiveness is often limited, however, due to the development of glucocorticoid resistance by a variety of molecular mechanisms. Here we performed an unbiased genome-wide CRISPR screen with the human T-cell leukemia cell line Jurkat to find previously unidentified genes required for GC-induced apoptosis. One such gene was KMT2D (also known as MLL2 or MLL4), which encodes a histone lysine methyltransferase whose mutations are associated with a variety of cancers, blood malignancies in particular, and are considered markers of poor prognosis. Knockout of KMT2D by CRISPR/Cas9 gene editing in Jurkat and several multiple myeloma cell lines downregulated GR protein expression. Surprisingly, this was not due to a reduction in GR transcripts, but rather to a decrease in the protein's half-life, primarily due to proteasomal degradation. Reconstitution of KMT2D expression restored GR levels. In contrast to the known ability of KMT2D to control gene transcription through covalent histone methylation, KMT2D-mediated upregulation of GR levels did not require its methyltransferase activity. Co-immunoprecipitation and proximity ligation assays found constitutive binding of KMT2D to the GR, which was enhanced in the presence of GC. These observations reveal KMT2D to be essential for the stabilization of cellular GR levels, and suggest a possible mechanism by which KMT2D mutations may lead to GC resistance in some malignancies.

Identifying high-risk multiple myeloma patients: A novel approach using a clonal gene signature

Multiple myeloma (MM) is a heterogeneous disease with a small subset of high-risk patients having poor prognoses. Identifying these patients is crucial for treatment management and strategic decisions. In this study, we developed a novel computational framework to define prognostic gene signatures by selecting genes with expression driven by clonal copy number alterations. We applied this framework to MM and developed a clonal gene signature (CGS) consisting of 22 genes and evaluated in five independent datasets. The CGS provided significant prognostic values after adjusting for well-established factors including cytogenetic abnormalities, International Staging System (ISS), and Revised ISS (R-ISS). Importantly, CGS demonstrated higher performance in identifying high-risk patients compared to the GEP70 and SKY92 signatures recommended for prognostic stratification of MM. CGS can further stratify patients into subgroups with significantly differential prognoses when applied to the high- and low-risk groups identified by GEP70 and SKY92. Additionally, CGS scores are significantly associated with patient response to dexamethasone, a commonly used treatment for MM. In summary, we proposed a computational framework that requires only gene expression data to identify CGSs for prognosis prediction. CGS provides a useful biomarker for improving prognostic stratification in MM, especially for identifying the highest-risk patients.

A network-based transcriptomic landscape of HepG2 cells uncovering causal gene-cytotoxicity interactions underlying drug-induced liver injury

Drug-induced liver injury (DILI) remains the main reason for drug development attritions largely due to poor mechanistic understanding. Toxicogenomic to interrogate the mechanism of DILI has been broadly performed. Gene coregulation network-based transcriptome analysis is a bioinformatics approach that potentially contributes to improve mechanistic interpretation of toxicogenomic data. Here we performed an extensive concentration time course response-toxicogenomic study in the HepG2 cell line exposed to 20 DILI compounds, 7 reference compounds for stress response pathways, and 10 agonists for cytokines and growth factor receptors. We performed whole transcriptome targeted RNA sequencing to more than 500 conditions and applied weighted gene coregulated network analysis to the transcriptomics data followed by the identification of gene coregulated networks (modules) that were strongly modulated upon the exposure of DILI compounds. Preservation analysis on the module responses of HepG2 and PHH demonstrated highly preserved adaptive stress response gene coregulated networks. We correlated gene coregulated networks with cell death onset and causal relationships of 67 critical target genes of these modules with the onset of cell death was evaluated using RNA interference screening. We identified GTPBP2, HSPA1B, IRF1, SIRT1, and TSC22D3 as essential modulators of DILI compound-induced cell death. These genes were also induced by DILI compounds in PHH. Altogether, we demonstrate the application of large transcriptome datasets combined with network-based analysis and biological validation to uncover the candidate determinants of DILI.

Elotuzumab: Empiric analysis of dexamethasone administration schedule

Elotuzumab in combination with dexamethasone and immunomodulating agents (IMiDs) lenalidomide or pomalidomide is 2nd to 4th line therapy for multiple myeloma. The labelled dosage of dexamethasone for use in conjunction with elotuzumab and IMiDs splits the dexamethasone dose into two administrations, one oral and one intravenous, on the days of each elotuzumab infusion. Administration of split dose dexamethasone on days of elotuzumab administration is based on the registration trials submitted for drug approval and was intended to ensure standard well-timed immunotherapy premedication using pharmacologically equivalent dexamethasone doses for both study arms. Administration of dexamethasone in the manner delineated by the elotuzumab product label adds complexity to the delivery of care. This commentary provides an empirical assessment of established medication safety and effectiveness which supports administration of dexamethasone standard intermittent dose instead of the split dose approach delineated on elotuzumab package insert. Simplification of regimen administration improves medication adherence, reduces the risk of inadvertent omission or duplication of medication therapy, and improves the workflow required for delivery of care.

Statin-induced Mitochondrial Priming Sensitizes Multiple Myeloma Cells to BCL2 and MCL-1 Inhibitors

The BCL2 inhibitor venetoclax promotes apoptosis in blood cancer cells and is approved for treatment of chronic lymphocytic leukemia and acute myeloid leukemia. However, multiple myeloma cells are frequently more dependent on MCL-1 for survival, conferring resistance to venetoclax. Here we report that mevalonate pathway inhibition with statins can overcome resistance to venetoclax in multiple myeloma cell lines and primary cells. In addition, statins sensitize to apoptosis induced by MCL-1 inhibitor, S63845. In retrospective analysis of venetoclax clinical studies in multiple myeloma, background statin use was associated with a significantly enhanced rate of stringent complete response and absence of progressive disease. Statins sensitize multiple myeloma cells to venetoclax by upregulating two proapoptotic proteins: PUMA via a p53-independent mechanism and NOXA via the integrated stress response. These findings provide rationale for prospective testing of statins with venetoclax regimens in multiple myeloma.

SIGNIFICANCE

BH3 mimetics including venetoclax hold promise for treatment of multiple myeloma but rational combinations are needed to broaden efficacy. This study presents mechanistic and clinical data to support addition of pitavastatin to venetoclax regimens in myeloma. The results open a new avenue for repurposing statins in blood cancer.

NK92 Expressing Anti-BCMA CAR and Secreted TRAIL for the Treatment of Multiple Myeloma: Preliminary In Vitro Assessment

Multiple myeloma (MM) has witnessed improved patient outcomes through advancements in therapeutic approaches. Notably, allogeneic stem cell transplantation, proteasome inhibitors, immunomodulatory drugs, and monoclonal antibodies have contributed to enhanced quality of life. Recently, a promising avenue has emerged with chimeric antigen receptor (CAR) T cells targeting B-cell maturation antigen (BCMA), expressed widely on MM cells. To mitigate risks associated with allogenic T cells, we investigated the potential of BCMA CAR expression in natural killer cells (NKs), known for potent cytotoxicity and minimal side effects. Using the NK-92 cell line, we co-expressed BCMA CAR and soluble tumor necrosis factor-related apoptosis-inducing ligand (sTRAIL) employing the piggyBac transposon system. Engineered NK cells (CAR-NK-92-TRAIL) demonstrated robust cytotoxicity against a panel of MM cell lines and primary patient samples, outperforming unmodified NK-92 cells with a mean difference in viability of 45.1% (±26.1%, depending on the target cell line). Combination therapy was explored with the proteasome inhibitor bortezomib (BZ) and γ-secretase inhibitors (GSIs), leading to a significant synergistic effect in combination with CAR-NK-92-TRAIL cells. This synergy was evident in cytotoxicity assays where a notable decrease in MM cell viability was observed in combinatorial therapy compared to single treatment. In summary, our study demonstrates the therapeutic potential of the CAR-NK-92-TRAIL cells for the treatment of MM. The synergistic impact of combining these engineered NK cells with BZ and GSI supports further development of allogeneic CAR-based products for effective MM therapy.

Efficacy and safety of venetoclax in patients with relapsed/refractory multiple myeloma: a meta-analysis

BACKGROUND

Venetoclax is clinically active in treating relapsed/refractory multiple myeloma (RRMM). This study evaluated the efficacy and safety of venetoclax or venetoclax with other agents in treating RRMM.

METHODS

PubMed, Web of Science, Embase, and Cochrane Library were comprehensively searched. We included studies investigating the efficacy and safety of venetoclax or venetoclax with other agents in treating RRMM. Overall response rates (ORR), stringent complete response rates (sCR), complete response rates (CR), very good partial response rates (VGPR), partial response rates (PR), stable disease (SD), progressive disease (PD) and adverse events were synthesized using either a random-effects model or a fixed-effects model.

RESULTS

A total of 7 clinical trials with 482 patients with RRMM were included. Concerning venetoclax with other agents, the pooled ORR, sCR, CR, VGPR, PR, SD, and PD were 0.76 (95% CIs: 0.62, 0.87), 0.11 (95% CIs: 0.04, 0.21), 0.18 (95% CIs: 0.11, 0.26), 0.16 (95% CIs: 0.12, 0.25), 0.29 (95% CIs: 0.25, 0.34), 0.07 (95% CIs: 0.05, 0.10), and 0.11 (95% CIs: 0.04, 0.23). The overall rate of adverse events ≥ Grade 3 was 0.84 (95% CIs: 0.77, 0.91). The most common non-hematologic adverse events were nausea, diarrhea, fatigue, back pain, and vomiting; hematologic adverse events included thrombocytopenia, neutropenia, anemia, leukopenia, and lymphopenia.

CONCLUSIONS

This study indicates that venetoclax alone or in combination with other agents reveals favorable treatment responses and acceptable adverse events in treating RRMM.

Exploring the impact of dexamethasone on gene regulation in myeloma cells

Among glucocorticoids (GCs), dexamethasone (Dex) is widely used in treatment of multiple myelomas. However, despite a definite benefit, all patients relapse. Moreover, the molecular basis of glucocorticoid efficacy remains elusive. To determine genomic response to Dex in myeloma cells, we generated bulk and single-cell multi-omics data and high-resolution contact maps of active enhancers and target genes. We show that a minority of glucocorticoid receptor-binding sites are associated with enhancer activity gains, increased interaction loops, and transcriptional activity. We identified and characterized a predominant enhancer enriched in cohesin (RAD21) and more accessible upon Dex exposure. Analysis of four gene-specific networks revealed the importance of the CTCF-cohesin couple and the synchronization of regulatory sequence openings for efficient transcription in response to Dex. Notably, these epigenomic changes are associated with cell-to-cell transcriptional heterogeneity, in particular, lineage-specific genes. As consequences, BCL2L11-encoding BIM critical for Dex-induced apoptosis and CXCR4 protective from chemotherapy-induced apoptosis are rather up-regulated in different cells. In summary, our work provides new insights into the molecular mechanisms involved in Dex escape.

Crosstalk between glucocorticoid and mineralocorticoid receptors boosts glucocorticoid-induced killing of multiple myeloma cells

The glucocorticoid receptor (GR) is a crucial drug target in multiple myeloma as its activation with glucocorticoids effectively triggers myeloma cell death. However, as high-dose glucocorticoids are also associated with deleterious side effects, novel approaches are urgently needed to improve GR action in myeloma. Here, we reveal a functional crosstalk between GR and the mineralocorticoid receptor (MR) that plays a role in improved myeloma cell killing. We show that the GR agonist dexamethasone (Dex) downregulates MR levels in a GR-dependent way in myeloma cells. Co-treatment of Dex with the MR antagonist spironolactone (Spi) enhances Dex-induced cell killing in primary, newly diagnosed GC-sensitive myeloma cells. In a relapsed GC-resistant setting, Spi alone induces distinct myeloma cell killing. On a mechanistic level, we find that a GR-MR crosstalk likely arises from an endogenous interaction between GR and MR in myeloma cells. Quantitative dimerization assays show that Spi reduces Dex-induced GR-MR heterodimerization and completely abolishes Dex-induced MR-MR homodimerization, while leaving GR-GR homodimerization intact. Unbiased transcriptomics analyses reveal that c-myc and many of its target genes are downregulated most by combined Dex-Spi treatment. Proteomics analyses further identify that several metabolic hallmarks are modulated most by this combination treatment. Finally, we identified a subset of Dex-Spi downregulated genes and proteins that may predict prognosis in the CoMMpass myeloma patient cohort. Our study demonstrates that GR-MR crosstalk is therapeutically relevant in myeloma as it provides novel strategies for glucocorticoid-based dose-reduction.

Changing paradigm in the treatment of amyloidosis: From disease-modifying drugs to anti-fibril therapy

Cardiac amyloidosis is a rare, debilitating, and usually fatal disease increasingly recognized in clinical practice despite patients presenting with non-specific symptoms of cardiomyopathy. The current standard of care (SoC) focuses on preventing further amyloid formation and deposition, either with anti-plasma cell dyscrasia (anti-PCD) therapies in light-chain (AL) amyloidosis or stabilizers of transthyretin (TTR) in transthyretin amyloidosis (ATTR). The SoC is supplemented by therapies to treat the complications arising from organ dysfunction; for example, heart failure, arrhythmia, and proteinuria. Advancements in treatments have improved patient survival, especially for those whose disease is detected and for whom treatment is initiated at an early stage. However, there still are many unmet medical needs, particularly for patients with severe disease for whom morbidity and mortality remain high. There currently are no approved treatments to reverse amyloid infiltration and deplete the amyloid fibrils already deposited in organs, which can continue to cause progressive dysfunction. Anti-fibril therapies aimed at removing the deposited fibrils are being investigated for safety and efficacy in improving outcomes for patients with severe disease. However, there is no clinical evidence yet that removing deposited amyloid fibrils will improve organ function, thereby improving quality of life or extending life. Nevertheless, anti-fibril therapies are actively being investigated in clinical trials to evaluate their ability to complement and synergize with current SoC.

Methylprednisolone pulse therapy promotes the differentiation of regulatory T cells by inducing the apoptosis of CD4+ T cells in patients with systemic lupus erythematosus

OBJECTIVES

To investigate the differentiation of regulatory T cells (Tregs) induced by methylprednisolone (MP) pulse therapy in patients with Systemic Lupus Erythematosus (SLE).

METHODS

We enrolled 30 patients with SLE and analyzed peripheral blood mononuclear cells (PBMCs) before and after MP pulse therapy. Peripheral Tregs, apoptosis of PBMCs subsets, and TGFβ production by monocytes was quantified by flow cytometry. Proliferation and IFN-γ production of CD4⁺ T cells were measured. Furthermore, TGFβ1 production by human monocyte-derived macrophages (HMDM) stimulated with MP-treated CD4⁺ T cells were quantified by ELISA.

RESULTS

Peripheral Tregs was significantly increased after MP pulse therapy (6.76 ± 1.46% vs. 3.82 ± 1.02%, p < 0.01), with an expansion of Nrp1^- induced Tregs (4.54 ± 0.46% vs. 1.75 ± 0.38%, p < 0.01). Proliferation and IFN-γ production of CD4⁺ T cells were significantly decreased after MP pulse therapy. MP pulse therapy induced CD4⁺ T cell apoptosis (early apoptosis, 26.34 ± 3.54% vs. 14.81 ± 2.89%, p < 0.01) and TGFβ expression on monocytes (6.02% vs. 2.45%, p < 0.01). Furthermore, MP induced CD4⁺ T cell apoptosis in vitro, which stimulated HMDM to produce TGFβ. Moreover, elevated TGFβ level in supernatant from HMDM stimulated with MP-treated CD4⁺ T cells promoted Tregs differentiation.

CONCLUSIONS

MP pulse therapy induces CD4⁺ T cell apoptosis, which promotes monocytes to produce TGFβ and further facilitates Tregs differentiation. Newly-differentiated Tregs suppress proliferation and IFN-γ production of CD4⁺ T cells and contribute to immunoregulatory milieu after MP pulse therapy.

Emerging Therapeutic Strategies to Overcome Drug Resistance in Multiple Myeloma

Simple Summary

Multiple myeloma is a deadly blood cancer, but fortunately drug development has substantially prolonged the lifespan of patients to average more than a decade after diagnosis with optimal therapy. As a result, the population of patients living with multiple myeloma has grown considerably. Through its course, patients suffer repeated relapses for which they require new lines of treatment. Currently, the key drug classes for treatment are immunomodulatory drugs, proteasome inhibitors, and monoclonal antibodies. The goal of this review is to summarize the understanding of the problem of resistance to these drugs, which is ultimately responsible for patient fatality. In addition, we will focus on how new agents that are promising in clinical trials overcome resistance.

Abstract

Multiple myeloma is a malignant plasma cell neoplasm that remains incurable and is ultimately fatal when patients acquire multi-drug resistance. Thus, advancing our understanding of the mechanisms behind drug resistance in multi-relapsed patients is critical for developing better strategies to extend their lifespan. Here, we review the understanding of resistance to the three key drug classes approved for multiple myeloma treatment: immunomodulatory drugs, proteasome inhibitors, and monoclonal antibodies. We consider how the complex, heterogenous biology of multiple myeloma may influence the acquisition of drug resistance and reflect on the gaps in knowledge where additional research is needed to improve our treatment approaches. Fortunately, many agents are currently being evaluated preclinically and in clinical trials that have the potential to overcome or delay drug resistance, including next-generation immunomodulatory drugs and proteasome inhibitors, novel small molecule drugs, chimeric antigen receptor T cells, antibody-drug conjugates, and bispecific antibodies. For each class, we discuss the potential of these strategies to overcome resistance through modifying agents within each class or new classes without cross-resistance to currently available drugs.

Targeting BCL-2 with venetoclax and dexamethasone in patients with relapsed/refractory t(11;14) multiple myeloma

Venetoclax (Ven) is a selective small-molecule inhibitor of BCL-2 that exhibits antitumoral activity against MM cells with t(11;14) translocation. We evaluated the safety and efficacy of Ven and dexamethasone (VenDex) combination in patients with t(11;14) positive relapsed/refractory (R/R) multiple myeloma (MM). This open-label, multicenter study had two distinct phases (phase one [P1], phase two [P2]). Patients in both phases received VenDex (oral Ven 800 mg/day + oral Dex 40 mg [20 mg for patients ≥75 years] on days 1, 8, and 15, per 21-day cycle). The primary objective of the P1 VenDex cohort was to assess safety and pharmacokinetics. Phase two further evaluated efficacy with objective response rate (ORR) and very good partial response or better. Correlative studies explored baseline BCL2 (BCL-2) and BCL2L1 (BCL-X_L ) gene expression, cytogenetics, and recurrent somatic mutations in MM. Twenty and 31 patients in P1 and P2 with t(11;14) positive translocation received VenDex. P1/P2 patients had received a median of 3/5 lines of prior therapy, and 20%/87% were refractory to daratumumab. Predominant grade 3/4 hematological adverse events (AEs) with ≥10% occurrence included lymphopenia (20%/19%), neutropenia (15%/7%), thrombocytopenia (10%/10%), and anemia (5%/16%). At a median follow-up of 12.3/9.2 months, ORR was 60%/48%. The duration of response estimate at 12 months was 50%/61%, and the median time to progression was 12.4/10.8 months. In biomarker evaluable patients, response to VenDex was independent of concurrent del(17p) or gain(1q) and mutations in key oncogenic signaling pathways, including MAPK and NF-kB. VenDex demonstrated efficacy and manageable safety in heavily-pre-treated patients with t(11;14) R/R MM.

Latest perspectives on glucocorticoid-induced apoptosis and resistance in lymphoid malignancies

Glucocorticoids are essential drugs in the treatment protocols of lymphoid malignancies. These steroidal hormones trigger apoptosis of the malignant cells by binding to the glucocorticoid receptor (GR), which is a member of the nuclear receptor superfamily. Long term glucocorticoid treatment is limited by two major problems: the development of glucocorticoid-related side effects, which hampers patient quality of life, and the emergence of glucocorticoid resistance, which is a gradual process that is inevitable in many patients. This emphasizes the need to reevaluate and optimize the widespread use of glucocorticoids in lymphoid malignancies. To achieve this goal, a deep understanding of the mechanisms governing glucocorticoid responsiveness is required, yet, a recent comprehensive overview is currently lacking. In this review, we examine how glucocorticoids mediate apoptosis by detailing GR's genomic and non-genomic action mechanisms in lymphoid malignancies. We continue with a discussion of the glucocorticoid-related problems and how these are intertwined with one another. We further zoom in on glucocorticoid resistance by critically analyzing the plethora of proposed mechanisms and highlighting therapeutic opportunities that emerge from these studies. In conclusion, early detection of glucocorticoid resistance in patients remains an important challenge as this would result in a timelier treatment reorientation and reduced glucocorticoid-instigated side effects.

Glucocorticoid receptor expression in multiple myeloma patients is a predictor of survival

Multiple myeloma (MM) is a blood neoplasia characterized by abnormal proliferation of plasma cells. Various treatments such as stem cell transplant (SCT), proteasome inhibitors, immune-modulating drugs, monoclonal antibodies and selective inhibitors of nuclear export have been routinely used to treat MM. However, relapse and treatment resistance are common problems in MM patients. Treatments are enhanced by Dexamethasone (Dex), a synthetic steroid that activates the glucocorticoid receptor (GR) which leads to apoptosis. To evaluate the potential impact of GR expression on overall survival, MM patient data from the CoMMpass study of 650 patients were analyzed. Multivariate modeling results show that increased GR expression at diagnosis is associated with a decreased risk of dying relative to those with lower levels of expression.

Deep profiling of apoptotic pathways with mass cytometry identifies a synergistic drug combination for killing myeloma cells

Multiple myeloma is an incurable and fatal cancer of immunoglobulin-secreting plasma cells. Most conventional therapies aim to induce apoptosis in myeloma cells but resistance to these drugs often arises and drives relapse. In this study, we sought to identify the best adjunct targets to kill myeloma cells resistant to conventional therapies using deep profiling by mass cytometry (CyTOF). We validated probes to simultaneously detect 26 regulators of cell death, mitosis, cell signaling, and cancer-related pathways at the single-cell level following treatment of myeloma cells with dexamethasone or bortezomib. Time-resolved visualization algorithms and machine learning random forest models (RFMs) delineated putative cell death trajectories and a hierarchy of parameters that specified myeloma cell survival versus apoptosis following treatment. Among these parameters, increased amounts of phosphorylated cAMP response element-binding protein (CREB) and the pro-survival protein, MCL-1, were defining features of cells surviving drug treatment. Importantly, the RFM prediction that the combination of an MCL-1 inhibitor with dexamethasone would elicit potent, synergistic killing of myeloma cells was validated in other cell lines, in vivo preclinical models and primary myeloma samples from patients. Furthermore, CyTOF analysis of patient bone marrow cells clearly identified myeloma cells and their key cell survival features. This study demonstrates the utility of CyTOF profiling at the single-cell level to identify clinically relevant drug combinations and tracking of patient responses for future clinical trials.

Dual targeting of BCL2 and MCL1 rescues myeloma cells resistant to BCL2 and MCL1 inhibitors associated with the formation of BAX/BAK hetero-complexes

Multiple myeloma is a plasma cell malignancy that escapes from apoptosis by heterogeneously over-expressing anti-apoptotic BCL2 proteins. Myeloma cells with a t(11;14) translocation present a particular vulnerability to BCL2 inhibition while a majority of myeloma cells relies on MCL1 for survival. The present study aimed to determine whether the combination of BCL2 and MCL1 inhibitors at low doses could be of benefit for myeloma cells beyond the single selective inhibition of BCL2 or MCL1. We identified that half of patients were not efficiently targeted neither by BCL2 inhibitor nor MCL1 inhibitor. Seventy percent of these myeloma samples, either from patients at diagnosis or relapse, presented a marked increase of apoptosis upon low dose combination of both inhibitors. Interestingly, primary cells from a patient in progression under venetoclax treatment were not sensitive ex vivo to neither venetoclax nor to MCL1 inhibitor, whereas the combination of both efficiently induced cell death. This finding suggests that the combination could overcome venetoclax resistance. The efficacy of the combination was also confirmed in U266 xenograft model resistant to BCL2 and MCL1 inhibitors. Mechanistically, we demonstrated that the combination of both inhibitors favors apoptosis in a BAX/BAK dependent manner. We showed that activated BAX was readily increased upon the inhibitor combination leading to the formation of BAK/BAX hetero-complexes. We found that BCLXL remains a major resistant factor of cell death induced by this combination. The present study supports a rational for the clinical use of venetoclax/S63845 combination in myeloma patients with the potential to elicit significant clinical activity when both single inhibitors would not be effective but also to overcome developed in vivo venetoclax resistance.

Implicating the Role of GILZ in Glucocorticoid Modulation of T-Cell Activation

Glucocorticoid-induced leucine zipper (GILZ) is a protein with multiple biological roles that is upregulated by glucocorticoids (GCs) in both immune and non-immune cells. Importantly, GCs are immunosuppressive primarily due to their regulation of cell signaling pathways that are crucial for immune system activity. GILZ, which is transcriptionally induced by the glucocorticoid receptor (GR), mediates part of these immunosuppressive, and anti-inflammatory effects, thereby controlling immune cell proliferation, survival, and differentiation. The primary immune cells targeted by the immunosuppressive activity of GCs are T cells. Importantly, the effects of GCs on T cells are partially mediated by GILZ. In fact, GILZ regulates T-cell activation, and differentiation by binding and inhibiting factors essential for T-cell function. For example, GILZ associates with nuclear factor-κB (NF-κB), c-Fos, and c-Jun and inhibits NF-κB-, and AP-1-dependent transcription. GILZ also binds Raf and Ras, inhibits activation of Ras/Raf downstream targets, including mitogen-activated protein kinase 1 (MAPK1). In addition GILZ inhibits forkhead box O3 (FoxO3) without physical interaction. GILZ also promotes the activity of regulatory T cells (Tregs) by activating transforming growth factor-β (TGF-β) signaling. Ultimately, these actions inhibit T-cell activation and modulate the differentiation of T helper (Th)-1, Th-2, Th-17 cells, thereby mediating the immunosuppressive effects of GCs on T cells. In this mini-review, we discuss how GILZ mediates GC activity on T cells, focusing mainly on the therapeutic potential of this protein as a more targeted anti-inflammatory/immunosuppressive GC therapy.

Whole-exon sequencing of human myeloma cell lines shows mutations related to myeloma patients at relapse with major hits in the DNA regulation and repair pathways

Background

Human myeloma cell lines (HMCLs) are widely used for their representation of primary myeloma cells because they cover patient diversity, although not fully. Their genetic background is mostly undiscovered, and no comprehensive study has ever been conducted in order to reveal those details.

Methods

We performed whole-exon sequencing of 33 HMCLs, which were established over the last 50 years in 12 laboratories. Gene expression profiling and drug testing for the 33 HMCLs are also provided and correlated to exon-sequencing findings.

Results

Missense mutations were the most frequent hits in genes (92%). HMCLs harbored between 307 and 916 mutations per sample, with TP53 being the most mutated gene (67%). Recurrent bi-allelic losses were found in genes involved in cell cycle regulation (RB1, CDKN2C), the NFκB pathway (TRAF3, BIRC2), and the p53 pathway (TP53, CDKN2A). Frequency of mutations/deletions in HMCLs were either similar to that of patients (e.g., DIS3, PRDM1, KRAS) or highly increased (e.g., TP53, CDKN2C, NRAS, PRKD2). MAPK was the most altered pathway (82% of HMCLs), mainly by RAS mutants. Surprisingly, HMCLs displayed alterations in epigenetic (73%) and Fanconi anemia (54%) and few alterations in apoptotic machinery. We further identified mutually exclusive and associated mutations/deletions in genes involved in the MAPK and p53 pathways as well as in chromatin regulator/modifier genes. Finally, by combining the gene expression profile, gene mutation, gene deletion, and drug response, we demonstrated that several targeted drugs overcome or bypass some mutations.

Conclusions

With this work, we retrieved genomic alterations of HMCLs, highlighting that they display numerous and unprecedented abnormalities, especially in DNA regulation and repair pathways. Furthermore, we demonstrate that HMCLs are a reliable model for drug screening for refractory patients at diagnosis or at relapse.

Electronic supplementary material

The online version of this article (10.1186/s13045-018-0679-0) contains supplementary material, which is available to authorized users.

A dual role for glucocorticoid-induced leucine zipper in glucocorticoid function: tumor growth promotion or suppression?

Glucocorticoids (GCs), important therapeutic tools to treat inflammatory and immunosuppressive diseases, can also be used as part of cancer therapy. In oncology, GCs are used as anticancer drugs for lymphohematopoietic malignancies, while in solid neoplasms primarily to control the side effects of chemo/radiotherapy treatments. The molecular mechanisms underlying the effects of GCs are numerous and often overlapping, but not all have been elucidated. In normal, cancerous, and inflammatory tissues, the response to GCs differs based on the tissue type. The effects of GCs are dependent on several factors: the tumor type, the GC therapy being used, the expression level of the glucocorticoid receptor (GR), and the presence of any other stimuli such as signals from immune cells and the tumor microenvironment. Therefore, GCs may either promote or suppress tumor growth via different molecular mechanisms. Stress exposure results in dysregulation of the hypothalamic-pituitary-adrenal axis with increased levels of endogenous GCs that promote tumorigenesis, confirming the importance of GCs in tumor growth. Most of the effects of GCs are genomic and mediated by the modulation of GR gene transcription. Moreover, among the GR-induced genes, glucocorticoid-induced leucine zipper (GILZ), which was cloned and characterized primarily in our laboratory, mediates many GC anti-inflammatory effects. In this review, we analyzed the possible role for GILZ in the effects GCs have on tumors cells. We also suggest that GILZ, by affecting the immune system, tumor microenvironment, and directly cancer cell biology, has a tumor-promoting function. However, it may also induce apoptosis or decrease the proliferation of cancer cells, thus inhibiting tumor growth. The potential therapeutic implications of GILZ activity on tumor cells are discussed here.

Omega-3 Polyunsaturated Fatty Acids Eicosapentaenoic Acid and Docosahexaenoic Acid Enhance Dexamethasone Sensitivity in Multiple Myeloma Cells by the p53/miR-34a/Bcl-2 Axis

Dexamethasone is widely used in multiple myeloma (MM) for its cytotoxic effects on lymphoid cells. However, many MM patients are resistant to dexamethasone, although some can benefit from dexamethasone treatment. In this study, we noted that ω-3 polyunsaturated fatty acids (PUFAs) enhanced the dexamethasone sensitivity of MM cells by inducing cell apoptosis. q-PCR analysis revealed that miR-34a could be significantly induced by PUFAs in U266 and primary MM cells. Transfection with miR-34a antagonist or miR-34a agomir could restore or suppress the dexamethasone sensitivity in U266 cells. Both luciferase reporter assay and Western blot showed that Bcl-2 is the direct target of miR-34a in MM cells. In addition, we observed that PUFAs induced p53 protein expression in MM cells under dexamethasone administration. Furthermore, suppressing p53 by its inhibitor, Pifithrin-α, regulated the miR-34a expression and modulated the sensitivity to dexamethasone in U266 cells. In summary, these results suggest that PUFAs enhance dexamethasone sensitivity to MM cells through the p53/miR-34a axis with a likely contribution of Bcl-2 suppression.

Glucocorticoid-Induced Leucine Zipper in Central Nervous System Health and Disease

The central nervous system (CNS) is a large network of intercommunicating cells that function to maintain tissue health and homeostasis. Considerable evidence suggests that glucocorticoids exert both neuroprotective and neurodegenerative effects on the CNS. Glucocorticoids act by binding two related receptors in the cytoplasm, the mineralocorticoid receptor (MR) and the glucocorticoid receptor (GR). The glucocorticoid receptor complex mediates cellular responses by transactivating target genes and by protein: protein interactions. The paradoxical effects of glucocorticoids on neuronal survival and death have been attributed to the concentration and the ratio of mineralocorticoid to glucocorticoid receptor activation. Glucocorticoid-induced leucine zipper (GILZ) is a recently identified protein transcriptionally upregulated by glucocorticoids. Constitutively, expressed in many tissues including brain, GILZ mediates many of the actions of glucocorticoids. It mimics the anti-inflammatory and anti-proliferative effects of glucocorticoids but exerts differential effects on stem cell differentiation and lineage development. Recent experimental data on the effects of GILZ following induced stress or trauma suggest potential roles in CNS diseases. Here, we provide a short overview of the role of GILZ in CNS health and discuss three potential rationales for the role of GILZ in Alzheimer's disease pathogenesis.

Repression of Mcl-1 and disruption of the Mcl-1/Bak interaction in myeloma cells couple ER stress to mitochondrial apoptosis

As myeloma cells actively produce and secrete immunoglobulins, they are prone to ER stress, which if unresolved leads to apoptosis. We found that myeloma cell death induced by the ER stressor Thapsigargin was highly variable, ranging from 2 to 89%. Induction of ATF4 and CHOP was observed in myeloma cells under Thapsigargin independently of cell death. The decrease in Mcl-1 was associated with protein translation inhibition and identified as a crucial factor in Thapsigargin sensitivity, since it was the only Bcl-2 family protein differentially modified between sensitive and resistant myeloma cells. Bak but not Bax was found to contribute to Thapsigargin-induced apoptosis. Appropriately, a basal Mcl-1/Bak interaction was demonstrated in Thapsigargin-sensitive cells. Of note, the only pro-apoptotic protein freed from Mcl-1 under Thapsigargin was Bak, whereas Mcl-1/Noxa or Mcl-1/Bim complexes were simultaneously increased. Thus, the disruption of the basal Mcl-1/Bak complex in Thapsigargin-sensitive cells seemed to be an essential event in cell death induction, probably favored by the induced Noxa and Bim BH3-only proteins. These findings underscore the implication of the Mcl-1/Bak axis in myeloma cell death triggered by Thapsigargin.

Lack of Association Between Dexamethasone and Long-Term Survival After Non-Small Cell Lung Cancer Surgery

OBJECTIVE

To evaluate the association between the use of intraoperative dexamethasone with an increase in recurrence-free survival (RFS) and overall survival (OS) after non-small cell lung cancer (NSCLC) surgery.

DESIGN

This was a propensity score-matched (PSM) retrospective study.

SETTING

Single academic center.

PARTICIPANTS

The study comprised patients with stage I through IIIa NSCLC. Patients were excluded if they were younger than 18 years, had missing data, and died within 30 days after surgery.

MEASUREMENTS AND MAIN RESULTS

Primary outcomes of the study were RFS and OS. The data were PSM. RFS and OS were evaluated using univariate and multivariate Cox proportional hazards models after PSM to assess the association between intraoperative dexamethasone use and the primary outcomes. A p value of<0.05 was considered statistically significant. After PSM, 436 patients were included in each treatment group. Adjusting for significant covariates, the multivariate analysis demonstrated no association between the use of dexamethasone and RFS (hazard ratio [95% confidence interval]: 0.98 [0.78-1.24]; p = 0.915). The multivariate analysis also demonstrated no association between the administration of dexamethasone and OS (hazard ratio [95% confidence interval]: 1.08 [0.81-1.44]; p = 0.58).

CONCLUSIONS

This study demonstrated that intraoperative dexamethasone administration to NSCLC patients was not associated with a significant impact on RFS and OS. The results were similar to a previous study on ovarian cancer patients. A randomized controlled study should be conducted to confirm the results of this study.