ALBERT

Description: The role of the intrinsic coagulation pathway in acute myocardial infarction is poorly defined. Both coagulation factors XII (FXII) and XI (FXI) support experimental thrombus propagation in animals. Additionally, humans with FXI deficiency have a lower incidence of thrombosis and stroke, however no such association has been established for FXII. Curiously, the incidence of previously verified myocardial infarction (MI) among 96 surviving FXI deficient subjects that were interviewed in an epidemiologic study was found to be similar to or possibly even higher than the recorded incidence of MI in an age/sex matched dataset from morbidity/mortality statistics of the general Israeli population (Salomon et al. J Thromb Haemost. 2003;1:658). However, the outcome of these coronary events were not reported, except for the fact that all interviewed FXI subjects were alive at the time of the interview. To investigate the contribution of FXI activation by FXIIa in experimental MI, we used a standard mouse model of acute myocardial ischemia (AMI). To inhibit FXI in the mouse, we utilized our monoclonal antibody (14E11) that targets the Apple 2 domain of FXI, and has been shown in vitro to inhibit the activation of FXI by factor XIIa, while not significantly inhibiting activation of FXI by thrombin. To evaluate the efficacy of 14E11 in reducing ischemic injury in mice, the left coronary artery (LCA) of wildtype male mice was reversibly ligated for 40 min, and 14E11 (1 mg/kg; iv) or vehicle was infused during the last 15 min of occlusion. Occlusion was confirmed by sustained S-T elevation, regional cyanosis and wall motion abnormalities. Following occlusion, the ligature was removed and the heart reperfused for 2 hr. To delineate the area of risk and ischemia, the LCA was re-occluded at 2 hr post-reperfusion and fluorescent polymers infused into the apex of the heart. The heart was excised, cut into 1 mm thick transverse slices and photographed under UV light to identify the area at risk. Tissue sections were additionally stained with 2,3,5-triphenyltetrazolium chloride solution and infarcted areas evaluated via morphometric analysis. The area at risk was evaluated as the percent of total heart volume and infarct size was calculated as the percentage of area at risk. Our results indicated that the area of risk did not differ between treatment groups, however treatment with 14E11 reduced infarct volume by 33% (p

Description: Severe bacterial sepsis often leads to a systemic procoagulant and proinflammatory condition that can manifest as disseminated intravascular coagulation, septic shock, and multiple organ failure. Because activation of the contact proteases factor XII (FXII), prekallikrein, and factor XI (FXI) can trigger coagulation and inflammatory responses, the contact factors have been considered potential targets for the treatment of sepsis. However, the pathogenic role of contact activation in severe infections has not been well defined. We therefore investigated whether an anticoagulant antibody (14E11) that selectively inhibits prothrombotic FXI activation by activated FXII (FXIIa) modifies the course of bowel perforation-induced peritoneal sepsis in mice. Early anticoagulation with 14E11 suppressed systemic thrombin- antithrombin complex formation, IL-6, and TNF-α levels, and reduced platelet consumption in the circulation and deposition in the blood vessels. Treatment with 14E11 within 12 hours after bowel perforation significantly improved survival compared with vehicle treatment, and the saturating dose did not increase tail bleeding. These data suggest that severe polymicrobial abdominal infection induces prothrombotic FXI activation, to the detriment of the host. Systemic anticoagulation by inhibiting FXI activation or FXIIa procoagulant activity during sepsis may therefore limit the development of disseminated intravascular coagulation without increasing bleeding risks.

Description: During surface-initiated blood coagulation in vitro, activated factor XII (fXIIa) converts factor XI (fXI) to fXIa. Whereas fXI deficiency is associated with a hemorrhagic disorder, factor XII deficiency is not, suggesting that fXI can be activated by other mechanisms in vivo. Thrombin activates fXI, and several studies suggest that fXI promotes coagulation independent of fXII. However, a recent study failed to find evidence for fXII-independent activation of fXI in plasma. Using plasma in which fXII is either inhibited or absent, we show that fXI contributes to plasma thrombin generation when coagulation is initiated with low concentrations of tissue factor, factor Xa, or α-thrombin. The results could not be accounted for by fXIa contamination of the plasma systems. Replacing fXI with recombinant fXI that activates factor IX poorly, or fXI that is activated poorly by thrombin, reduced thrombin generation. An antibody that blocks fXIa activation of factor IX reduced thrombin generation; however, an antibody that specifically interferes with fXI activation by fXIIa did not. The results support a model in which fXI is activated by thrombin or another protease generated early in coagulation, with the resulting fXIa contributing to sustained thrombin generation through activation of factor IX.

Description: Background: Hypomethylating agents (HMAs) (e.g., azacitidine (aza), decitabine (dec)) and lenalidomide (len) are approved agents and used in the treatment of patients with myelodysplastic syndromes (MDS) or acute myeloid leukemia (AML). Despite their widespread use, HMAs fail in the majority of MDS and AML patients, and len fails in 75% of non-del(5q) MDS. Unfortunately, no method exists to predict disease response, thus the management of MDS and AML patients is challenging. Predicting treatment response would improve treatment effectiveness, restrict treatment-related adverse events to those who would benefit, and reduce health care costs. Ideally, patient prediction would be based on disease biology. Aim: To determine the biological and clinical predictive values of a genomics-informed computational biology method in patients with AML and MDS who are treated with aza, dec or len. Methods: Patients with AML or MDS were recruited in a prospective clinical trial (NCT02435550) designed to assess predictive values by comparing computer predictions of treatment response to actual clinical response. Genomic profiling was conducted by conventional cytogenetics, whole exome sequencing (SureSelectXT Clinical Research Exome, Agilent), and array CGH (Agilent). These genomic results were inputted into computational biology software (Cellworks Group), which generates disease-specific protein network maps using PubMed and other online resources. Digital drug simulations were conducted by quantitatively measuring drug effect on a cell growth score, which is a composite of cell proliferation, viability and apoptosis. Each patient-specific protein network map was digitally screened for the extent by which aza, dec or len reduced simulated disease growth in a dose-respondent manner. Treatment was physician's choice based on SOC. Before initiating treatment, treating physicians were masked to the results of whole exome sequencing and computational predictions. Clinical outcomes were prospectively recorded. To be eligible for efficacy assessment, patients must have had at least 4 cycles of HMA treatment or 2 cycles of len treatment. For AML, CR+PR was used to define response (IWG 2003). For MDS, CR+PR+HI was used to define response (IWG 2006). To validate the predicted protein network perturbations, Western blot assays were performed on pertinent pathway proteins. Comparisons of computer-predicted versus actual responses were performed using 2x2 tables, from which prediction values were calculated. Fisher's exact test was used to compare prediction values of the genomics-informed computer method versus empiric drug administration. Results: Between June 2015 and June 2016, 80 patients were recruited. 40/80 (50%) had AML and 40/80 had MDS (50%). The median age was 66 (range 24-91). 44/80 (55%) were treatment-naïve and 36/80 (45%) were treatment-refractory. 99% completed all planned molecular tests and computational analyses. Laboratory validation study of computer-predicted, activated protein networks in 19 samples from 13 different patients showed correct prediction of 5 activated networks (Akt2, Akt3, PIK3CA, p38, Erk1/2) in 17 samples, exhibiting 89% accuracy. At the time of this report, 20/80 patients were eligible for efficacy evaluation. 6/20 patients showed clinical response to SOC therapy, while 14/20 did not achieve clinical response. 18 patients' outcome predictions were correctly matched to their actual clinical outcomes, and 2/20 were incorrectly matched, resulting in 90% prediction accuracy, 75% positive predictive value (PPV), 100% negative predictive value (NPV), 100% sensitivity, and 86% specificity. The accuracy of the genomics-informed computer method was significantly greater than empiric drug administration (p=1.664e-05). New genomic signature rules were discovered to correlate with clinical response after aza, dec or len. Conclusions: A computational method that models multiple genomic abnormalities simultaneously showed high predictive value of protein network perturbations and clinical outcomes after standard of care treatments. The network method uncovered molecular reasons for drug failure and highlighted resistance pathways that could be targeted to recover chemosensitivity. This technology could also be used to establish eligibility criteria for precision enrollment in drug development trials. Disclosures Vali: Cellworks Group: Employment. Abbasi:Cellworks: Employment. Kumar:Cellworks group: Employment. Kumar Singh:Cellworks group: Employment. Basu:Cellworks Group: Employment. Kumar:Cellworks Group: Employment. Husain:Cellworks Group: Employment. Wingard:Ansun: Consultancy; Merck: Consultancy; Fate Therapeutics: Consultancy; Astellas: Consultancy; Gilead: Consultancy.

Description: BALB/c mice were immunized with human factor V. The immunogen was a mixture of procofactor (factor V) and thrombin-activated cofactor (factor Va). Spleen cells were obtained from an immunized animal and fused with NS-1 murine myeloma cells. Hybrid cell cultures were assayed for the production of antibodies to human factor V and factor Va by a solid-phase radioimmunoassay. Factor V and/or factor-Va-specific antibodies were detected in 38 of the 96 cultures assayed. The cells from 10 of these positive cultures were subcloned by limiting dilution and grown as ascites tumors in BALB/c mice. Ascitic fluids were obtained and characterized with respect to their binding interaction with human factor V and factor Va. Three hybridoma cell lines produce monoclonal antibodies that react equally well with factor V and factor Va. Another antibody reacts with both antigens, but the reactivity with factor V is better than with factor Va. An additional two antibodies react with factor Va better than factor V in the radioimmunoassay (RIA). The remaining four antibodies react exclusively with factor V. A previously described murine monoclonal antibody to human factor V (alpha HFV-1) has been used to study the peptides produced during the thrombin-catalyzed activation of human factor V. This antibody binds both factor V and factor Va, releases them at high ionic strength, and has an apparent dissociation constant for factor Va of 3 x 10(-9)M. When human factor V (mol wt 330,000) is activated by thrombin and passed over an alpha HFV-1-Sepharose affinity resin, factor Va binds and subsequently can be eluted. The eluate in 1.2 M NaCl contains two fragments of apparent mol wt 93,000 and 70,000. EDTA, which inactivates factor Va, promotes release of the mol wt 93,000 fragment from factor Va bound to the antibody. Subsequent elution with 1.2 M NaCl releases the mol wt 70,000 fragment. These observations indicate that human factor Va is a two subunit protein and that the epitope for alpha HFV-1 is on the mol wt 70,000 fragment.

Description: Mantle cell lymphoma (MCL) has the poorest long-term survival of all the lymphoma subtypes. CHOP-like regimens currently represent the standard of care for individuals with MCL, but traditional chemotherapeutic regimens do not elicit disease free survival times that are comparable to other sub classes of B-cell lymphomas. Median survival rate of a MCL patient still is approximately 3 years. Therefore new, targeted therapeutics are needed to improve the clinical outcome of MCL. The aim of the study was to identify and characterize combination effects achieved when flavopiridol, a Cyclin D1 inhibitor, and bortezomib, a proteosome inhibitor, are used in a combination setting together or with other agents contained in the CHOP regimen. Two MCL cell lines, Z138 and NCEB-1, were tested for cytotoxicity of drugs alone and in combinations, where alamar blue was used to assess cell viability. The resulting data were analyzed by using the median effect principle introduced by Chou and Talalay. In addition, mechanisms governing measured cytotoxic effects and combination effects were studied by DNA staining (propidium iodine), Caspase 3/7 activation and by western analysis of cyclinD1, NfkB, Bcl-xl, Bax and Bcl-2. The combination of bortezomib and flavopiridol was found to be synergistic in both cell lines studied. Synergistic interactions were dependent on drug-to-drug ratio. In NCEB-1, a ratio 1:12000 (bortezomib:flavopiridol) determined based on the IC90 of each of the individual agents showed synergy over a broad range of fa values (representing the fraction of affected cells). At ratios based on the IC10 and IC50 of the agents when used alone produced effects that were estimated to be antagonistic by the median effect principle. In the Z138 cell line, drug to drug ratios based on the individual agent IC50 and IC90 resulted in synergistic interactions. Consistent with the objective of identifying synergistic combinations, a clear dose reduction was observed to achieve a given therapeutic goal (e.g. 90% cell kill). 10-fold less bortezomib and 55-fold less flavopiridol would be required to achieve 90% cell death/cytostasis based on addition of the agents alone. Mechanistic studies showed that bortezomib in the combination and alone activated the caspase-dependent apoptotic pathway. The combination of bortezomib and flavopiridol for treatment of MCL would appear to an appropriate choice for clinical evaluation, however novel strategies must be developed in order to insure that combination effects observed in cell based screening assays are capture in patients. In this regard it is important to consider drug-drug ratio effects as well as combination engendered toxicities, both parameters that can be evaluated through careful pharmacodynamic assessments in well defined animal models of MCL.

Description: Childhood acute myeloid leukemia (AML) has a poor prognosis with standard chemotherapy. Allogeneic bone marrow transplantation (BMT) in remission improves the outlook only for the one third of patients with sibling donors. Autologous BMT with a lower morbidity and mortality is available to all. In this study, maximum cytoreduction was achieved by intensive early chemotherapy. Final intensification, with autologous BMT was offered to all those remaining in first complete remission (CR). Patients received two induction and two consolidation courses of intensively scheduled chemotherapy. Cytoreduction was assessed on day 14 and remission was assessed after courses 2 and 4. Bone marrow was harvested after recovery from the second consolidation course or after the first maintenance course and separated on a discontinuous percoll gradient before cryopreservation. Twenty-eight of 31 consecutively enrolled patients achieved CR. Three relapsed early and, of the 25 eligible, 24 underwent autologous BMT. Twenty-three patients received high-dose melphalan and 1 received busulphan and cyclophosphamide before autologous BMT at a median of 113 days (range, 86 to 301) after initial CR. Trilineage engraftment occurred in all. Neutrophil recovery to greater than 0.5 x 10(9)/L occurred at a median of 46 days (range, 13 to 92) after autologous BMT. Platelet recovery was delayed, with a median time to achieve greater than 20 x 10(9)/L of 42 days (range, 18 to 215). With a minimum follow up of 25 months following autologous BMT only 3 children have relapsed. The 5-year event-free survival rate (EFS) from diagnosis is 68% (95% confidence interval, 46% to 90%). Five- year EFS following autologous BMT is 87% (95% confidence interval, 67% to 100%). Autologous BMT with high-dose melphalan administration after intensive chemotherapy has produced EFS equivalent to allogeneic BMT and is associated with a strikingly low relapse rate. High-dose melphalan appears to be a valuable agent for conditioning therapy in AML.

Description: Infection of monocytes with human immunodeficiency virus type 1Ba-L (HIV-1Ba-L ) is significantly inhibited by treatment with the serine protease inhibitor, secretory leukocyte protease inhibitor (SLPI). SLPI does not appear to act on virus directly, but rather the inhibitory activity is most likely due to interaction with the host cell. The current study was initiated to investigate how SLPI interacts with monocytes to inhibit infection. SLPI was found to bind to monocytes with high affinity to a single class of receptor sites (∼7,000 receptors per monocyte, KD = 3.6 nmol/L). The putative SLPI receptor was identified as a surface protein with a molecular weight of 55 ± 5 kD. A well-characterized function of SLPI is inhibition of neutrophil elastase and cathepsin G. However, two SLPI mutants (or muteins) that contain single amino acid substitutions and exhibit greatly reduced protease inhibitory activity still bound to monocytes and retained anti–HIV-1 activity. SLPI consists of two domains, of which the C-terminal domain contains the protease inhibiting region. However, when tested independently, neither domain had potent anti–HIV-1 activity. SLPI binding neither prevented virus binding to monocytes nor attenuated the infectivity of any virus progeny that escaped inhibition by SLPI. A polymerase chain reaction (PCR)-based assay for newly generated viral DNA demonstrated that SLPI blocks at or before viral DNA synthesis. Therefore, it most likely inhibits a step of viral infection that occurs after virus binding but before reverse transcription. Taken together, the unique antiviral activity of SLPI, which may be independent of its previously characterized antiprotease activity, appears to reside in disruption of the viral infection process soon after virus binding.

Description: Here we report stable gene transfer in cord blood-derived CD34+ hematopoietic stem cells using a hyperactive nonviral Sleeping Beauty (SB) transposase (SB100X). In colony-forming assays, SB100X mediated the highest efficiency (24%) of stable Discosoma sp red fluorescent protein (DsRed) reporter gene transfer in committed hematopoietic progenitors compared with both the early-generation hyperactive SB11 transposase and the piggyBac transposon system (1.23% and 3.8%, respectively). In vitro differentiation assays further demonstrated that SB100X-transfected CD34+ cells can develop into DsRed+ CD4+CD8+ T (3.17%-21.84%; median, 7.97%), CD19+ B (3.83%-18.66%; median, 7.84%), CD56+CD3− NK (3.53%-79.98%; median, 7.88%), and CD33+ myeloid (7.59%-15.63%; median, 9.48%) cells. SB100X-transfected CD34+ cells achieved approximately 46% engraftment in NOD-scid IL2γcnull (NOG) mice. Twelve weeks after transplantation, 0.57% to 28.96% (median, 2.79%) and 0.49% to 34.50% (median, 5.59%) of total human CD45+ cells in the bone marrow and spleen expressed DsRed, including CD19+ B, CD14+ monocytoid, and CD33+ myeloid cell lineages. Integration site analysis revealed SB transposon sequences in the human chromosomes of in vitro differentiated T, B, NK, and myeloid cells, as well as in human CD45+ cells isolated from bone marrow and spleen of transplanted NOG mice. Our results support the continuing development of SB-based gene transfer into human hematopoietic stem cells as a modality for gene therapy.

Description: CCAAT displacement protein (cux/CDP) is an atypical homeodomain protein that represses expression of several developmentally regulated lymphoid and myeloid genes in vitro, including gp91-phox, immunoglobulin heavy chain, the T-cell receptor β and γ chains, and CD8. To determine how this activity affects cell development in vivo, a hypomorphic allele of cux/CDP was created by gene targeting. Homozygous mutant mice (cux/CDPΔHD/ΔHD) demonstrated a partial neonatal lethality phenotype. Surviving animals suffered from a wasting disease, which usually resulted in death between 2 and 3 weeks of age. Analysis of T lymphopoiesis demonstrated that cux/CDPΔHD/ΔHD mice had dramatically reduced thymic cellularity due to enhanced apoptosis, with a preferential loss of CD4+CD8+ thymocytes. Ectopic CD25 expression was also observed in maturing thymocytes. B lymphopoiesis was also perturbed, with a 2- to 3-fold reduction in total bone marrow B-lineage cells and a preferential loss of cells in transition from pro-B/pre-BI to pre-BII stages due to enhanced apoptosis. These lymphoid abnormalities were independent of effects related to antigen receptor rearrangement. In contrast to the lymphoid demise, cux/CDPΔHD/ΔHD mice demonstrated myeloid hyperplasia. Bone marrow reconstitution experiments identified that many of the hematopoietic defects were linked to microenvironmental effects, suggesting that underexpression of survival factors or overexpression of death-inducing factors accounted for the phenotypes observed. Tumor necrosis factor (TNF) levels were elevated in several tissues, especially thymus, suggesting that TNF may be a target gene for cux/CDP-mediated repression. These data suggest that cux/CDP regulates normal hematopoiesis, in part, by modulating the levels of survival and/or apoptosis factors expressed by the microenvironment.