Dysregulated cell cycling is a universal hallmark of cancer and is often mediated by abnormal activation of cyclin-dependent kinases (CDKs) and their cyclin partners. Over-expression of individual ...complexes are reported in multiple myeloma (MM), making them attractive therapeutic targets. In this study, we investigate the preclinical activity of a novel small-molecule multi-CDK inhibitor, AT7519, in MM. We show the anti-MM activity of AT7519 displaying potent cytotoxicity and apoptosis; associated with in vivo tumor growth inhibition and prolonged survival. At the molecular level, AT7519 inhibited RNA polymerase II (RNA pol II) phosphorylation, a CDK9, 7 substrate, associated with decreased RNA synthesis confirmed by ³H Uridine incorporation. In addition, AT7519 inhibited glycogen synthase kinase 3β (GSK-3β) phosphorylation; conversely pretreatment with a selective GSK-3 inhibitor and shRNA GSK-3β knockdown restored MM survival, suggesting the involvement of GSK-3β in AT7519-induced apoptosis. GSK-3β activation was independent of RNA pol II dephosphorylation confirmed by α-amanitin, a specific RNA pol II inihibitor, showing potent inhibition of RNA pol II phosphorylation without corresponding effects on GSK-3β phosphorylation. These results offer new insights into the crucial, yet controversial role of GSK-3β in MM and show significant anti-MM activity of AT7519, providing the rationale for its clinical evaluation in MM. Oncogene (2010) 29, 2325-2336; doi: 10.1038/onc.2009.510; published online 25 January 2010 Keywords: myeloma; cyclin-dependent kinase; GSK-3β; RNA pol II
Proteasome inhibition is an effective therapy for multiple myeloma (MM) patients; however, the emergence of drug resistance is common. Novel therapeutic strategies to overcome proteasome inhibitor ...resistance are needed. In this study, we examined whether targeting deubiquitylating (DUB) enzymes upstream of 20S proteasome overcomes proteasome inhibitor resistance. Gene expression analysis, immunohistochemical studies of MM patient bone marrow, reverse transcription-PCR and protein analysis show that Rpn11/POH1, a DUB enzyme upstream of 20S proteasome, is more highly expressed in patient MM cells than in normal plasma cells. Importantly, Rpn11 expression directly correlates with poor patient survival. Loss-of-function studies show that Rpn11-siRNA knockdown decreases MM cell viability. Pharmacological inhibition of Rpn11 with O-phenanthroline (OPA) blocks cellular proteasome function, induces apoptosis in MM cells and overcomes resistance to proteasome inhibitor bortezomib. Mechanistically, Rpn11 inhibition in MM cells activates caspase cascade and endoplasmic stress response signaling. Human MM xenograft model studies demonstrate that OPA treatment reduces progression of tumor growth and prolongs survival in mice. Finally, blockade of Rpn11 increases the cytotoxic activity of anti-MM agents lenalidomide, pomalidomide or dexamethasone. Overall, our preclinical data provide the rationale for targeting DUB enzyme Rpn11 upstream of 20S proteasome to enhance cytotoxicity and overcome proteasome inhibitor resistance in MM.
Multiple myeloma is the most common indication for high-dose chemotherapy with autologous stem cell support (ASCT) in North America today. Stem cell procurement for ASCT has most commonly been ...performed with stem cell mobilization using colony-stimulating factors with or without prior chemotherapy. The target CD34+ cell dose to be collected as well as the number of apheresis performed varies throughout the country, but a minimum of 2 million CD34+ cells/kg has been traditionally used for the support of one cycle of high-dose therapy. With the advent of plerixafor (AMD3100) (a novel stem cell mobilization agent), it is pertinent to review the current status of stem cell mobilization for myeloma as well as the role of autologous stem cell transplantation in this disease. On June 1, 2008, a panel of experts was convened by the International Myeloma Foundation to address issues regarding stem cell mobilization and autologous transplantation in myeloma in the context of new therapies. The panel was asked to discuss a variety of issues regarding stem cell collection and transplantation in myeloma especially with the arrival of plerixafor. Herein, is a summary of their deliberations and conclusions.
LBH589 is a novel pan-histone deacetylase (HDAC) inhibitor that has potent antitumor activity in multiple myeloma and other hematological malignancies. However, its impact on the immune system has ...not been defined. We here evaluated the effects of LBH589 on human myeloid dendritic cells (DCs) at clinically relevant concentrations. Exposure to LBH589 affected the surface molecule expression on immature and mature DCs, which was associated with DC maturation (CD83↓), antigen presentation (human leukocyte antigen-ABC↓) and T-cell co-stimulation (CD40↓ and CD86↑). LBH589 decreased both protein and polysaccharide antigen uptake capacities by DCs. Importantly, LBH589 impaired DC function to stimulate antigen-specific immune responses, resulting in the significant reduction of invariant natural killer T-cell (CD1d-restricted) and T-cell (major histocompatibility complex-restricted) activation in innate and adaptive immunity. LBH589 also significantly repressed the production of interleukin (IL)-6, IL-10, IL-12p70, IL-23 and tumor necrosis factor-α by Toll-like receptor (TLR)3 and TLR4-induced DC activation, indicating an important role of HDAC activity in immune regulation and inflammation. RelB, a component of the nuclear factor-κ B signaling pathway, was the key component regulated by HDAC inhibition in DCs. Together, our preclinical study demonstrates that LBH589 significantly impairs the phenotype and function of DCs, indicating a need for monitoring the immune status in patients receiving HDAC inhibitor therapy. It also provides a rationale to evaluate LBH589 activity for the treatment of inflammation.
We evaluated a cocktail of HLA-A2-specific peptides including heteroclitic XBP1 US184-192 (YISPWILAV), heteroclitic XBP1 SP367-375 (YLFPQLISV), native CD138260-268 (GLVGLIFAV) and native CS1239-247 ...(SLFVLGLFL), for their ability to elicit multipeptide-specific cytotoxic T lymphocytes (MP-CTLs) using T cells from smoldering multiple myeloma (SMM) patients. Our results demonstrate that MP-CTLs generated from SMM patients' T cells show effective anti-MM responses including CD137 (4-1BB) upregulation, CTL proliferation, interferon-γ production and degranulation (CD107a) in an HLA-A2-restricted and peptide-specific manner. Phenotypically, we observed increased total CD3(+)CD8(+) T cells (>80%) and cellular activation (CD69(+)) within the memory SMM MP-CTL (CD45RO(+)/CD3(+)CD8(+)) subset after repeated multipeptide stimulation. Importantly, SMM patients could be categorized into distinct groups by their level of MP-CTL expansion and antitumor activity. In high responders, the effector memory (CCR7(-)CD45RO(+)/CD3(+)CD8(+)) T-cell subset was enriched, whereas the remaining responders' CTL contained a higher frequency of the terminal effector (CCR7(-)CD45RO(-)/CD3(+)CD8(+)) subset. These results suggest that this multipeptide cocktail has the potential to induce effective and durable memory MP-CTL in SMM patients. Therefore, our findings provide the rationale for clinical evaluation of a therapeutic vaccine to prevent or delay progression of SMM to active disease.
Multiple myeloma is a plasma cell malignancy characterized by recurrent IgH translocations and well described genomic heterogeneity. Although transcriptome profiles in multiple myeloma has been ...described, landscape of expressed fusion genes and their clinical impact remains unknown. To provide a comprehensive and detailed fusion gene cartography and suggest new mechanisms of tumorigenesis in multiple myeloma, we performed RNA sequencing in a cohort of 255 newly diagnosed and homogeneously treated multiple myeloma patients with long follow-up. Here, we report that patients have on average 5.5 expressed fusion genes. Kappa and lambda light chains and IgH genes are main partners in a third of all fusion genes. We also identify recurrent fusion genes that significantly impact both progression-free and overall survival and may act as drivers of the disease. Lastly, we find a correlation between the number of fusions, the age of patients and the clinical outcome, strongly suggesting that genomic instability drives prognosis of the disease.
We have previously demonstrated that interleukin-17A (IL-17) producing T helper 17 cells are significantly elevated in blood and bone marrow (BM) in multiple myeloma (MM) and IL-17A promotes MM cell ...growth via the expression of IL-17 receptor. In this study, we evaluated anti-human IL-17A human monoclonal antibody (mAb), AIN457 in MM. We observe significant inhibition of MM cell growth by AIN457 both in the presence and the absence of BM stromal cells (BMSCs). Although IL-17A induces IL-6 production, AIN457 significantly downregulated IL-6 production and MM cell adhesion in MM-BMSC co-culture. AIN457 also significantly inhibited osteoclast cell differentiation. More importantly, in the SCIDhu model of human myeloma administration of AIN457 weekly for 4 weeks after the first detection of tumor in mice led to a significant inhibition of tumor growth and reduced bone damage compared with isotype control mice. To understand the mechanism of action of anti-IL-17A mAb, we report, here, that MM cells express IL-17A. We also observed that IL-17A knockdown inhibited MM cell growth and their ability to induce IL-6 production in co-cultures with BMSC. These pre-clinical observations suggest efficacy of AIN457 in myeloma and provide the rationale for its clinical evaluation for anti-myeloma effects and for improvement of bone disease.
Human telomerase, the reverse transcriptase which extends the life span of a cell by adding telomeric repeats to chromosome ends, is expressed in most cancer cells but not in the majority of normal ...somatic cells. Inhibition of telomerase therefore holds great promise as anticancer therapy. We have synthesized a novel telomerase inhibitor GRN163L, a lipid-attached phosphoramidate oligonucleotide complementary to template region of the RNA subunit of telomerase. Here, we report that GRN163L is efficiently taken up by human myeloma cells without any need of transfection and is resistant to nucleolytic degradation. The exposure of myeloma cells to GRN163L led to an effective inhibition of telomerase activity, reduction of telomere length and apoptotic cell death after a lag period of 2-3 weeks. Mismatch control oligonucleotides had no effect on growth of myeloma cells. The in vivo efficacy of GRN163L was confirmed in two murine models of human multiple myeloma. In three independent experiments, significant reduction in tumor cell growth and better survival than control mice was observed. Furthermore, GRN163L-induced myeloma cell death could be significantly enhanced by Hsp90 inhibitor 17AAG. These data provide the preclinical rationale for clinical evaluation of GRN163L in myeloma and in combination with 17AAG.
Background
Upfront autologous hematopoietic stem cell transplantation (AHCT) remains an important therapy in the management of patients with multiple myeloma (MM), a disease of older adults.
Methods
...The authors investigated the outcomes of AHCT in patients with MM who were aged ≥70 years. The Center for International Blood and Marrow Transplant Research (CIBMTR) database registered 15,999 patients with MM in the United States within 12 months of diagnosis during 2013 through 2017; a total of 2092 patients were aged ≥70 years. Nonrecurrence mortality (NRM), disease recurrence and/or progression (relapse; REL), progression‐free survival (PFS), and overall survival (OS) were modeled using Cox proportional hazards models with age at transplantation as the main effect. Because of the large sample size, a P value <.01 was considered to be statistically significant a priori.
Results
An increase in AHCT was noted in 2017 (28%) compared with 2013 (15%) among patients aged ≥70 years. Although approximately 82% of patients received melphalan (Mel) at a dose of 200 mg/m2 overall, 58% of the patients aged ≥70 years received Mel at a dose of 140 mg/m2. On multivariate analysis, patients aged ≥70 years demonstrated no difference with regard to NRM (hazard ratio HR 1.3; 99% confidence interval 99% CI, 1‐1.7 P = .06), REL (HR, 1.03; 99% CI, 0.9‐1.1 P = 0.6), PFS (HR, 1.06; 99% CI, 1‐1.2 P = 0.2), and OS (HR, 1.2; 99% CI, 1‐1.4 P = .02) compared with the reference group (those aged 60‐69 years). In patients aged ≥70 years, Mel administered at a dose of 140 mg/m2 was found to be associated with worse outcomes compared with Mel administered at a dose of 200 mg/m2, including day 100 NRM (1% 95% CI, 1%‐2% vs 0% 95% CI, 0%‐1%; P = .003), 2‐year PFS (64% 95% CI, 60%‐67% vs 69% 95% CI, 66%‐73%; P = .003), and 2‐year OS (85% 95% CI, 82%‐87% vs 89% 95% CI, 86%‐91%; P = .01), likely representing frailty.
Conclusions
The results of the current study demonstrated that AHCT remains an effective consolidation therapy among patients with MM across all age groups.
Upfront autologous hematopoietic stem cell transplantation (AHCT) remains an important therapy for the management of patients with multiple myeloma, which is a disease of older adults. The results of the current large database study confirm that AHCT remains an effective consolidation therapy in fit older adults aged ≥70 years.
A prominent feature of most cancers including Barrett's adenocarcinoma (BAC) is genetic instability, which is associated with development and progression of disease. In this study, we investigated ...the role of recombinase (hsRAD51), a key component of homologous recombination (HR)/repair, in evolving genomic changes and growth of BAC cells. We show that the expression of RAD51 is elevated in BAC cell lines and tissue specimens, relative to normal cells. HR activity is also elevated and significantly correlates with RAD51 expression in BAC cells. The suppression of RAD51 expression, by short hairpin RNA (shRNA) specifically targeting this gene, significantly prevented BAC cells from acquiring genomic changes to either copy number or heterozygosity (P<0.02) in several independent experiments employing single-nucleotide polymorphism arrays. The reduction in copy-number changes, following shRNA treatment, was confirmed by Comparative Genome Hybridization analyses of the same DNA samples. Moreover, the chromosomal distributions of mutations correlated strongly with frequencies and locations of Alu interspersed repetitive elements on individual chromosomes. We conclude that the hsRAD51 protein level is systematically elevated in BAC, contributes significantly to genomic evolution during serial propagation of these cells and correlates with disease progression. Alu sequences may serve as substrates for elevated HR during cell proliferation in vitro, as they have been reported to do during the evolution of species, and thus may provide additional targets for prevention or treatment of this disease.
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