ALBERT

Description: Inorganic arsenic trioxide (As2O3 ) was recently shown to induce apoptosis in NB4 promyelocytic leukemic cells. We have investigated the effects of the organic arsenical, melarsoprol (a drug used for treatment of trypanosomiasis), upon induction of apoptosis in cell lines representative of chronic B-cell lymphoproliferative disorders. An Epstein-Barr virus (EBV)-transformed B-prolymphocytic cell line (JVM-2), an EBV-transformed B-cell chronic lymphocytic leukemia (B-CLL) cell line (I83CLL), and one non–EBV-transformed B-CLL cell line (WSU-CLL) were used as targets. Dose-response experiments with melarsoprol (10−7 to 10−9 mol/L) were performed over 96 hours. Unexpectedly, we found that melarsoprol caused a dose- and time-dependent inhibition of survival and growth in all three cell lines. In contrast, As2O3 at similar concentrations had no effect on either viability or growth. After 24 hours, all three cell lines treated with melarsoprol (10−7 mol/L) exhibited morphologic characteristics of apoptosis. We also observed prominent concentration-dependent downregulation of bcl-2 mRNA after 24 hours of exposure to melarsoprol in WSU-CLL, I83CLL, and JVM-2 cells. Decrease of bcl-2 protein expression was also observed in all three cell lines, whereas As2O3 had no effect on this parameter. We conclude that melarsoprol may inhibit the growth of lymphoid leukemic cell by promoting programmed cell death. Results of these studies suggest that melarsoprol shows promising therapeutic activity in these diseases, and a study to evaluate clinical effects of this drug has been initiated.

Description: Key Points Pathogen-inactivated platelets were noninferior in preventing bleeding only in intention-to-treat analysis. In contrast to animal models, alloimmunization could not be prevented when using pathogen-inactivated platelets.

Description: Interferon-γ (IFN-γ) upregulates expression of certain genes in monocytes, including cell-surface molecules such as HLA class II, B7, and ICAM-1. IFN-γ also potentiates production of cytokines such as tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and IL-12. Conversely, IL-10 downregulates expression of many of these same genes and often antagonizes the effects of IFN-γ. IL-10 is known to inhibit TNF-α production in lipopolysaccharide (LPS)-stimulated monocytes; however, the effects of IL-10 on TNF receptor (TNF-R) expression are not well defined. We examined the effects of IL-10 on production of both membrane-associated (m) and soluble (s) TNF-R type II (sTNF-RII) by purified human CD14+ monocytes. We also compared the effects of IFN-γ and IL-10 on production of TNF-α and sTNF-RII by these cells. Monocytes constitutively expressed low levels of TNF-RII mRNA and mTNF-RII protein. LPS stimulation induced rapid, but transient loss (shedding) of mTNF-RII molecules and a delayed, but marked increase in TNF-RII mRNA levels. IL-10 increased expression of both mTNF-RII and sTNF-RII by LPS-stimulated monocytes, whereas IFN-γ decreased their expression. The increased levels of sTNF-RII in cultures of IL-10–treated monocytes correlated directly with increased levels of TNF-RII mRNA and inversely with the levels of TNF-α mRNA. The ability of IL-10 to upregulate TNF-RII gene expression was transcriptionally mediated because actinomycin D blocked this effect. Furthermore, IL-10 treatment did not alter the half-life of TNF-RII mRNA transcripts in LPS-stimulated monocytes. To further examine the mechanism by which IL-10 potentiates TNF-RII gene expression, a 1.8-kb fragment of the human TNF-RII promoter cloned into a luciferase expression vector (pGL2-basic) was transfected into the IL-10–responsive macrophage cell line, RAW264.7. Although IL-10 alone induced only minimal promoter activity in these cells, it markedly increased the LPS-induced response, providing further evidence that the ability of IL-10 to amplify TNF-RII gene expression is transcriptionally controlled. Together, these findings demonstrate that IL-10 coordinately downregulates expression of TNF-α and upregulates expression of TNF-RII, particularly the soluble form of this receptor, in monocytes.

Description: Inorganic arsenic trioxide (As2O3 ) was recently shown to induce apoptosis in NB4 promyelocytic leukemic cells. We have investigated the effects of the organic arsenical, melarsoprol (a drug used for treatment of trypanosomiasis), upon induction of apoptosis in cell lines representative of chronic B-cell lymphoproliferative disorders. An Epstein-Barr virus (EBV)-transformed B-prolymphocytic cell line (JVM-2), an EBV-transformed B-cell chronic lymphocytic leukemia (B-CLL) cell line (I83CLL), and one non–EBV-transformed B-CLL cell line (WSU-CLL) were used as targets. Dose-response experiments with melarsoprol (10−7 to 10−9 mol/L) were performed over 96 hours. Unexpectedly, we found that melarsoprol caused a dose- and time-dependent inhibition of survival and growth in all three cell lines. In contrast, As2O3 at similar concentrations had no effect on either viability or growth. After 24 hours, all three cell lines treated with melarsoprol (10−7 mol/L) exhibited morphologic characteristics of apoptosis. We also observed prominent concentration-dependent downregulation of bcl-2 mRNA after 24 hours of exposure to melarsoprol in WSU-CLL, I83CLL, and JVM-2 cells. Decrease of bcl-2 protein expression was also observed in all three cell lines, whereas As2O3 had no effect on this parameter. We conclude that melarsoprol may inhibit the growth of lymphoid leukemic cell by promoting programmed cell death. Results of these studies suggest that melarsoprol shows promising therapeutic activity in these diseases, and a study to evaluate clinical effects of this drug has been initiated.

Description: Background: CXCR4 is a chemokine receptor overexpressed in more than 20 tumor types, including malignant plasma cells. The CXCR4/CXCL12 (SDF-1) axis has been known for many years as a critical regulator of tumor proliferation, cell, as well as migration into and out of the bone marrow. Ulocuplumab (BMS- 936564) is a first in class, fully human IgG4 monoclonal anti-CXCR4 antibody which inhibits the binding of CXCR4 to CXCL12. This study aimed to determine the safety, tolerability, pharmacokinetics, pharmacodynamics, and clinical activity of Ulocuplumab alone and in combination with lenalidomide plus dexamethasone (Len-Dex), or in combination with bortezomib plus dexamethasone (Bor-Dex) in subjects with relapsed/refractory multiple myeloma. Patients / Methods: Patients were eligible for this trial if they were 18 years of age or older with relapsed or relapsed/refractory multiple myeloma after having received at least 2 prior lines of treatment. Patients in whom who both lenalidomide and bortezomib had failed were not excluded from re-treatment with the same regimen. Patients were enrolled at four cancer centers in the U.S. from October 2011 to March 2014. Ulocuplumab (1, 3 and 10 mg/kg) was dose escalated with a 3-plus-3 design with doses of Len-Dex or Bor-Dex to identify maximum tolerated dose (MTD). Ulocuplumab was given weekly in combination with either 25mg lenalidomide on days 1-21 and 40mg oral dexamethasone on days 1, 8, 15, and 22 of the 28-day cycles on Arm A or 1.3 mg/m2 bortezomib on days 1, 4, 8, and 11 and 20mg oral dexamethasone on days 1, 2, 4, 5, 8, 9, 11, and 12 of the 21-day cycles on Arm B since cycle 2. The primary endpoints for this study were dose-limiting toxicities. Other key safety endpoints included incidence of adverse events (AE), AEs leading to discontinuation, SAEs, deaths, and laboratory abnormalities. The efficacy endpoints included overall responses, duration of response, and time to response. Responses were assessed using the IMWG criteria. Results: Forty-six patients were enrolled (median age, 60 years; range, 53-67). The median number of prior therapies was 3 (range, 1-11), with 70.0% of patients having received ≥ 3 lines of treatment. Ulocuplumab was escalated to a maximum of 10 mg/kg without reaching MTD. The most common treatment-related adverse events of any grade were neutropenia (13 patients, 43.3%), diarrhea (10 patients, 33.3%), thrombocytopenia (10 patients, 33.3%), and fatigue (7 patients, 23.3%) in Arm A; and thrombocytopenia (6 patients, 37.5%), fatigue (4 patients, 25.0%) and anemia (4 patients, 25.0%) in Arm B. The overall response rate (≥ partial response) for all subjects in escalation and expansion was 44.4% (20/45). The median time to response was 1.5 months (range 0.4-7.8 months) for Arm A and 1.0 month (range 0.5-3.7 months) for Arm B, respectively. Of note, the combination of Ulocuplumab with Len-Dex showed a high response rate of 55.2% and a clinical benefit rate ( ≥ minimal response) of 72.4%, including patients who have been previously treated with lenalidomide. Conclusion: This study shows that the blockade of the CXCR4-CXCL12 axis by Ulocuplumab is safe and has an encouraging response rate of over 50% in the Len-Dex arm of patients with relapsed/refractory myeloma. The distinct mechanisms of action of this antibody, as well as its non- cross resistance with currently approved approaches, make it a new class of anti-myeloma drug that warrants further exploration and evaluation in future clinical trials. Disclosures Ghobrial: Takeda: Consultancy; Celgene: Consultancy; BMS: Consultancy; Janssen: Consultancy. Richardson:Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees; BMS: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees. Anderson:Celgene: Consultancy; Takeda Millennium: Consultancy; Bristol Myers Squibb: Consultancy; Gilead: Membership on an entity's Board of Directors or advisory committees; Oncopep: Equity Ownership; C4 Therapeutics: Equity Ownership. Becker:GlycoMimetics: Research Funding.

Description: Interleukin-10 (IL-10) helps maintain polarized T-helper cells in a T-helper lymphocyte 2 (Th2) phenotype. Part of this process involves the prevention of the development of Th1 cells, which are a primary source of interferon γ (IFNγ), a potent activator of monocytes and an inhibitor of Th2 proliferation. Because monocytes and macrophages are important mediators of Th1-type responses, such as delayed-type hypersensitivity, we sought to determine if IL-10 could directly mediate inhibition of IFNγ- and IFN-induced gene expression in these cells. Highly purified monocytes were incubated with IL-10 for 60 to 90 minutes before the addition of IFNγ or IFN. IL-10 preincubation resulted in the inhibition of gene expression for several IFN-induced genes, such as IP-10, ISG54, and intercellular adhesion molecule-1. The reduction in gene expression resulted from the ability of IL-10 to suppress IFN-induced assembly of signal transducer and activator of transcription (STAT) factors to specific promoter motifs on IFN- and IFNγ-inducible genes. This was accomplished by preventing the IFN-induced tyrosine phosphorylation of STAT1, a component of both IFN- and IFNγ-induced DNA binding complexes. Therefore, IL-10 can directly inhibit STAT-dependent early response gene expression induced by both IFN and IFNγ in monocytes by suppressing the tyrosine phosphorylation of STAT1. This may occur through the ability of IL-10 to induce expression of the gene, suppressor of cytokine signaling 3 (SOCS3).

Description: Interleukin-10 (IL-10) is a potent monocyte regulatory cytokine that inhibits gene expression of proinflammatory mediators. In this study, we investigated the mechanism by which IL-10 downregulates expression of intercellular adhesion molecule-1 (ICAM-1) on the cell surface of normal human monocytes activated with interferon-γ (IFN-γ). IL-10 inhibition of IFN-γ–induced ICAM-1 expression was apparent as early as 3 hours and was blocked by an anti–IL-10 antibody but not by an isotype-matched control antibody. Northern blot analysis showed that IL-10 reduced the accumulation of ICAM-1 mRNA in IFN-γ–stimulated monocytes. IL-10 inhibition of ICAM-1 steady-state mRNA was detected at 3 hours and remained at 24 hours. Nuclear run-on transcription assays showed that IL-10 inhibited the rate of IFN-γ–induced transcription of the ICAM-1 gene, and mRNA stability studies showed that IL-10 did not alter the half-life of IFN-γ–induced ICAM-1 message. Thus, IL-10 inhibits IFN-γ–induced ICAM-1 expression in monocytes primarily at the level of gene transcription. Activation of IFN-γ–responsive genes requires tyrosine phosphorylation of the transcriptional factor STAT-1α (signal transducer and activator of transcription-1α). However, IL-10 did not affect IFN-γ–induced tyrosine phosphorylation of STAT-1α or alter STAT-1α binding to the IFN-γ response element (IRE) in the ICAM-1 promoter. Instead, IL-10 prevented IFN-γ–induced binding activity at the NF-κB site of the tumor necrosis factor α (TNF-α)–responsive NF-κB/C-EBP composite element in the ICAM-1 promoter. These data indicate that IL-10 inhibits IFN-γ–induced transcription of the ICAM-1 gene by a regulatory mechanism that may involve NF-κB.