The pharmacokinetics of therapeutic arsenic trioxide in acute promyelocytic leukemia patients.

Arsenic trioxide (ATO) treats Acute Promyelocytic Leukemia (APL). ATO is converted from inorganic arsenic (iAs) to methylated (MAs) and dimethylated (DMAs) metabolites, which are excreted in the urine. Methylation of iAs is important in detoxification, as iAs exposure is deleterious to health. We examined ATO metabolism in 25 APL patients, measuring iAs, MAs, and DMAs. Plasma total iAs increased after ATO administration, followed by a rapid decline, reaching trough levels by 4-6 h. We identified two patterns of iAs metabolism between 6 and 24 h after infusion: in Group 1, iAs increased and were slowly converted to MAs and DMAs, whereas in Group 2, iAs was rapidly metabolized. These patterns were associated with smoking and different treatments: ATO with all-trans retinoic acid (ATRA) alone vs. ATO preceded by ATRA and chemotherapy. Our data suggest that smoking and prior chemotherapy exposure may be associated with ATO metabolism stimulation, thus lowering the effective blood ATO dose.

Correction to: Sequencing and curation strategies for identifying candidate glioblastoma treatments.

Following publication of the original article [1], it was reported that the given name of the fourteenth author was incorrectly published. The incorrect and the correct names are given below.

Sequencing and curation strategies for identifying candidate glioblastoma treatments.

BACKGROUND: Prompted by the revolution in high-throughput sequencing and its potential impact for treating cancer patients, we initiated a clinical research study to compare the ability of different sequencing assays and analysis methods to analyze glioblastoma tumors and generate real-time potential treatment options for physicians. METHODS: A consortium of seven institutions in New York City enrolled 30 patients with glioblastoma and performed tumor whole genome sequencing (WGS) and RNA sequencing (RNA-seq; collectively WGS/RNA-seq); 20 of these patients were also analyzed with independent targeted panel sequencing. We also compared results of expert manual annotations with those from an automated annotation system, Watson Genomic Analysis (WGA), to assess the reliability and time required to identify potentially relevant pharmacologic interventions. RESULTS: WGS/RNAseq identified more potentially actionable clinical results than targeted panels in 90% of cases, with an average of 16-fold more unique potentially actionable variants identified per individual; 84 clinically actionable calls were made using WGS/RNA-seq that were not identified by panels. Expert annotation and WGA had good agreement on identifying variants [mean sensitivity = 0.71, SD = 0.18 and positive predictive value (PPV) = 0.80, SD = 0.20] and drug targets when the same variants were called (mean sensitivity = 0.74, SD = 0.34 and PPV = 0.79, SD = 0.23) across patients. Clinicians used the information to modify their treatment plan 10% of the time. CONCLUSION: These results present the first comprehensive comparison of technical and machine augmented analysis of targeted panel and WGS/RNA-seq to identify potential cancer treatments.

Heme Dissociation from Myoglobin in the Presence of the Zwitterionic Detergent N,N-Dimethyl-N-Dodecylglycine Betaine: Effects of Ionic Liquids.

We have investigated myoglobin protein denaturation using the zwitterionic detergent Empigen BB (EBB, N,N-Dimethyl-N-dodecylglycine betaine). A combination of absorbance, fluorescence, and circular dichroism spectroscopic measurements elucidated the protein denaturation and heme dissociation from myoglobin. The results indicated that Empigen BB was not able to fully denature the myoglobin structure, but apparently can induce the dissociation of the heme group from the protein. This provides a way to estimate the heme binding free energy, ΔGdissociation. As ionic liquids (ILs) have been shown to perturb the myoglobin protein, we have investigated the effects of the ILs 1-butyl-3-methylimidazolium chloride (BMICl), 1-ethyl-3-methylimidazolium acetate (EMIAc), and 1-butyl-3-methylimidazolium tetrafluoroborate (BMIBF4) in aqueous solution on the ΔGdissociation values. Absorbance experiments show the ILs had minimal effect on ΔGdissociation values when compared to controls. Fluorescence and circular dichroism data confirm the ILs have no effect on heme dissociation, demonstrating that low concentrations ILs do not impact the heme dissociation from the protein and do not significantly denature myoglobin on their own or in combination with EBB. These results provide important data for future studies of the mechanism of IL-mediated protein stabilization/destabilization and biocompatibility studies.

Heavy chain transfer by tumor necrosis factor-stimulated gene 6 to the bikunin proteoglycan.

We present data that hyaluronan (HA) polysaccharides, about 14-86 monosaccharides in length, are capable of accepting only a single heavy chain (HC) from inter-α-inhibitor via transfer by tumor necrosis factor-stimulated gene 6 (TSG-6) and that this transfer is irreversible. We propose that either the sulfate groups (or the sulfation pattern) at the reducing end of the chondroitin sulfate (CS) chain of bikunin, or the core protein itself, enables the bikunin proteoglycan (PG) to accept more than a single HC and permits TSG-6 to transfer these HCs from its relatively small CS chain to HA. To test these hypotheses, we investigated HC transfer to the intact CS chain of the bikunin PG, and to the free chain of bikunin. We observed that both the free CS chain and the intact bikunin PG were only able to accept a single HC from inter-α-inhibitor via transfer by TSG-6 and that HCs could be swapped from the bikunin PG and its free CS chain to HA. Furthermore, a significant portion of the bikunin PG was unable to accept a single heavy chain. We discuss explanations for these observations, including the intracellular assembly of inter-α-inhibitor. In summary, these data demonstrate that the sulfation of the CS chain of bikunin and/or its core protein promote HC transfer by TSG-6 to its relatively short CS chain, although they are insufficient to enable the CS chain of bikunin to accept more than one HC in the absence of other cofactors.

Irreversible heavy chain transfer to chondroitin.

We have recently demonstrated that the transfer of heavy chains (HCs) from inter-α-inhibitor, via the enzyme TSG-6 (tumor necrosis factor-stimulated gene 6), to hyaluronan (HA) oligosaccharides is an irreversible event in which subsequent swapping of HCs between HA molecules does not occur. We now describe our results of HC transfer experiments to chondroitin sulfate A, chemically desulfated chondroitin, chemoenzymatically synthesized chondroitin, unsulfated heparosan, heparan sulfate, and alginate. Of these potential HC acceptors, only chemically desulfated chondroitin and chemoenzymatically synthesized chondroitin were HC acceptors. The kinetics of HC transfer to chondroitin was similar to HA. At earlier time points, HCs were more widely distributed among the different sizes of chondroitin chains. As time progressed, the HCs migrated to lower molecular weight chains of chondroitin. Our interpretation is that TSG-6 swaps the HCs from the larger, reversible sites on chondroitin chains, which function as HC acceptors, onto smaller chondroitin chains, which function as irreversible HC acceptors. HCs transferred to smaller chondroitin chains were unable to be swapped off the smaller chondroitin chains and transferred to HA. HCs transferred to high molecular weight HA were unable to be swapped onto chondroitin. We also present data that although chondroitin was a HC acceptor, HA was the preferred acceptor when chondroitin and HA were in the same reaction mixture.

Irreversible heavy chain transfer to hyaluronan oligosaccharides by tumor necrosis factor-stimulated gene-6.

The covalent transfer of heavy chains (HCs) from inter-α-inhibitor (IαI) to hyaluronan (HA) via the protein product of tumor necrosis factor-stimulated gene-6 (TSG-6) forms the HC-HA complex, a pathological form of HA that promotes the adhesion of leukocytes to HA matrices. The transfer of HCs to high molecular weight (HMW) HA is a reversible event whereby TSG-6 can shuffle HCs from one HA molecule to another. Therefore, HMW HA can serve as both an HC acceptor and an HC donor. In the present study, we show that transfer of HCs to low molecular weight HA oligosaccharides is an irreversible event where subsequent shuffling does not occur, i.e. HA oligosaccharides from 8 to 21 monosaccharide units in length can serve as HC acceptors, but are unable to function as HC donors. We show that the HC-HA complex is present in the synovial fluid of mice subjected to systemic and monoarticular mouse models of rheumatoid arthritis. Furthermore, we demonstrate that HA oligosaccharides can be used, with TSG-6, to irreversibly shuffle HCs from pathological, HMW HC-HA to HA oligosaccharides, thereby restoring HC-HA matrices from the inflamed joint to their normal state, unmodified with HCs. This process was also effective for HC-HA in the synovial fluid of human rheumatoid arthritis patients (in vitro).

The effect of hyaluronan hydrogel on fat graft survival.

BACKGROUND: Autologous fat transplantation is a common technique for soft tissue augmentation in aesthetic and reconstructive surgery; however, the degree of fat graft take can be unpredictable. Hyaluronan has been shown to be a promising cell carrier in adipose tissue engineering. OBJECTIVES: The authors investigate the effect of a hyaluronan hydrogel on fat graft survival, angiogenesis, and volume maintenance in a rat model. METHODS: Fat was harvested from the groins of 27 rats, processed, and injected beneath the animals' dorsums to form 2 grafts: 1 containing fat alone and 1 containing fat and hyaluronan hydrogel in a 1:1 mix (fat-HA). The grafts were scanned in vivo under high-resolution computed tomography at baseline and prior to euthanasia at 4, 12, and 20 weeks to measure total fat-HA graft volume as well as the volume of the fat component alone. Histological studies were performed after sacrifice to evaluate fat necrosis and blood vessel density. RESULTS: All grafts were clinically viable. Overall, fat necrosis was significantly reduced in the fat-HA grafts compared with the grafts containing fat alone (P < .001). This difference was most profound at 4 weeks (P = .008) but did not reach statistical significance at 12 and 20 weeks. At 12 weeks, blood vessel density in the fat-HA grafts was significantly greater than in the grafts containing fat alone (P = .016), but this did not reach statistical significance at 4 or 20 weeks. At 20 weeks, the fat component of the fat-HA graft had significantly less volume loss than the fat-alone graft (P = .008). CONCLUSIONS: When mixed with fat, hyaluronan hydrogel can improve early fat graft survival and may enhance vascularity and prolong volume maintenance.

Three dimensional culture of fresh and vitrified mouse pre-antral follicles in a hyaluronan-based hydrogel: a preliminary investigation of a novel biomaterial for in vitro follicle maturation.

BACKGROUND: Folliculogenesis within the ovary requires interaction between somatic cell components and the oocyte. Maintenance of 3-dimensional (3-D) architecture and granulosa-oocyte interaction may be critical for successful in vitro maturation of follicles. Testing of novel biomaterials for the 3-D culture of follicles may ultimately lead to a culture model that can support the longer in vitro culture intervals needed for in vitro maturation of human oocytes from ovarian tissue biopsies. METHODS: A novel tyramine-based hyaluronan (HA) hydrogel was tested for its biocompatibility with ovarian follicles. The HA was prepared at concentrations from 2 to 5 mg/ml. HA hydrogel was also formulated and tested with matrix proteins (ECM). Enzymatically isolated pre-antral follicles from the ovaries of 10-12 day SJL pups were divided amongst control (CT) and HA treatments. The growth of both fresh and vitrified follicles was assessed after encapsulation in the hydrogel. The basal culture medium was MEM alpha supplemented with FSH, LH, ITS and 5% FBS. Maturation was triggered by addition of hCG and EGF after in vitro culture (IVC). Outcome parameters monitored were follicle morphology, survival after IVC, antrum formation, GVBD and MII formation. Differences between treatments were analyzed. RESULTS: HA and ECM-HA encapsulated follicles looked healthy and maintained their 3-D architecture during IVC. In control cultures, the follicles flattened and granulosa:oocyte connections appeared fragile. Estradiol secretion per follicle was significantly higher by Day 12 in ECM-HA compared to HA or CT (4119, 703 and 1080 pg/ml, respectively). HA and ECM-HA cultured follicles had similar survival rates (62% and 54%, respectively), percent GV breakdown (96-97%), MII formation (47-48%) and oocyte diameters at the end of IVC. Control cultures differed significantly in percent GVBD (85%) and MII formation (67%) . Vitrified-warmed follicles encapsulated in HA had an oocyte maturation rate to MII of 54% as compared to 57% in non-embedded follicles. CONCLUSIONS: Initial testing of this new and unique HA-based hydrogel was quite promising. The ease of follicle encapsulation in HA, its optical transparency and ability to be molded combined with its support of follicle growth, estradiol secretion and resumption of meiosis make this HA-hydrogel particularly attractive as model for 3-D ovarian follicle culture.

Identification of unique synergistic drug combinations associated with downexpression of survivin in a preclinical breast cancer model system.

An in-vitro 72-h assay using median effect analysis and curve shift analysis was used to evaluate the utility of potentially clinically useful combinations of agents for synergism or antagonism. Six human breast cancer cell lines, both receptor rich and receptor poor, were studied.Panobinostat (LBH-589), a pan histone deacetylase inhibitor with a multitude of biological effects, exhibits time-dependent synergistic effects in breast cancer cell lines with docetaxel, doxorubicin, or gemcitabine in clinically relevant concentrations. Survivin expression was markedly downregulated in the presence of panobinostat with gemcitabine. Bortezomib, a proteasome inhibitor,markedly enhanced the cytotoxic effects of panobinostat combined with gemcitabine. Panobinostat did not demonstrate universal enhancement of cytotoxic drugs,and therefore, synergy was dependent on the second agent selected. No synergy was noted with anti-Her2 agents in Her2 overexpressing cell lines. Metformin combined with panobinostat demonstrated no synergy in this test system. These effects were confirmed by an apoptosis assay and caspase-3 production. A positive drug interaction was identified. The triplet of panobinostat with either doxorubicin/carboplatin or gemcitabine/carboplatin was especially potent in all cell lines. As all these agents are clinically available, further studies of the potent combinations are warranted.

The histone deacetylase inhibitor panobinostat demonstrates marked synergy with conventional chemotherapeutic agents in human ovarian cancer cell lines.

Although platinum based therapy has improved short term survival of patients with metastatic ovarian cancer, the majority of patients continue to relapse and eventually die of their disease. Currently, a plethora of agents are in development, but how to combine them to enhance efficacy remains largely empiric. We have used short in vitro culture of defined cell lines with application of promising agents and analysis for cell death using a MTT assay to identify potentially useful combinations. Using median effect analysis, curve shift analysis and apoptosis assays, we can identify when agents are synergistic or antagonistic when applied together. Up to three agents can be studied in combination. Using three cell lines: SK-OV3, CaOV-3, and ES-2 (a clear cell tumor), we have identified that panobinostat (LBH-589), a broad histone deacetylase inhibitor in clinical trials, demonstrates global synergy with gemcitabine, with paclitaxel, and additive to synergistic effects with 5'DFUR. The triplet of panobinostat, doxorubicin, and carboplatin is especially synergistic in these cell lines. These effects are cytotoxic and not cytostatic. As all these agents are used clinically, we have identified combinations which warrant further investigation.

Effect of metals on ß-actin and total protein synthesis in cultured human intestinal epithelial cells.

INTRODUCTION: As an important structural protein, ß-actin is associated with anchoring of tight junctions (TJs) to the cell scaffold. Caco-2 cells, an immortal intestinal epithelial cell line, rely on ß-actin to form intact monolayers with high transepithelial electrical resistance in cell culture inserts. METHODS: We examined the effect of six metals on expression of ß-actin mRNA and ß-actin synthesis, on total and net production of newly synthesized proteins, on paracellular transport of TJ markers, and on cell viability in confluent monolayers. [(3)H]-glycine and [(3)H]-tyrosine were used as indicators of newly synthesized proteins in the absence or presence of increasing concentrations of arsenic, cadmium, copper, manganese, mercury and nickel. The monolayers were exposed to 24-h single exposures as well as continuous daily repeated doses of metals for 48-h and 96-h. RESULTS: Results suggest that decreases in newly synthesized proteins, in which ß-actin represents about 10%, correlated with 2- to 5-fold higher expression of ß-actin mRNA for the higher concentrations of metals. Interestingly, IC(50)s calculated for each chemical for 24-h acute and 48- and 96-h repeated dosing experiments, using the MTT viability assay and paracellular permeability markers, decreased newly synthesized and total proteins to 10% and 40% of control, respectively. DISCUSSION: Overall, the results indicate that, at equivalent concentrations, the metals affect ß-actin mRNA and newly synthesized proteins before cell viability and paracellular permeability are compromised. Consequently the results help in elucidating mechanisms of metal cytotoxicity that lead to understanding the relationship between tight junction integrity, paracellular transport, and cell viability.

Mitral annular remodeling to treat functional mitral regurgitation: a pilot acute study in a canine model.

BACKGROUND: The aim of this study was to evaluate the feasibility and efficacy of the injection of a nonabsorbable substance into the base of the left ventricle (LV) to treat functional mitral regurgitation (MR). METHODS: Tyramine-based hyaluronan hydrogel was injected into the base of the LV of the beating heart in a canine model of rapid ventricular pacing-induced functional MR (n = 4). The severity of MR was evaluated by epicardial echocardiography before and after hydrogel injection. RESULTS: The injection improved MR grade from 3.4 +/- 0.8 to 1.3 +/- 0.5 (P = .006) without inducing hemodynamic instability or any evidence of myocardial ischemia. We noted significant decreases in the septal-lateral dimension at the mitral annulus (3.4 +/- 0.4 cm to 2.9 +/- 0.3 cm; P = .039) and MR volume (20.6 +/- 7.3 mm3 to 5.2 +/- 2.2 mm3; P = .044). CONCLUSIONS: A novel treatment consisting of hydrogel injection into the base of the LV between the 2 papillary muscles was found to be feasible and effective for reducing functional MR in a canine model.

In-vitro synergism of m-TOR inhibitors, statins, and classical chemotherapy: potential implications in acute leukemia.

Classical chemotherapy has an active, but limited, role in acute leukemia with relapse common in adult patients. Recent evidence has implicated signal transduction pathways in leukemic progression and also in resistance to cytotoxic therapy. We have used a short-term, in-vitro incubation assay with cytotoxic analysis by MTT, confirmed by histone-associated DNA fragmentation, to evaluate both classical and nonclassical combinations of drugs. Isobologram median effect analysis, confirmed by curve shift analysis, was used to identify synergy and antagonism. Fluvastatin, a prenylation inhibitor, demonstrates global enhancement of the effects of classical agents in both AML-193 and KG-1 cell lines. Similarly, the m-TOR inhibitors, RAD-001 (everolimus) and rapamycin, also cause time-dependent global enhancement of cytotoxic agents. At clinically achievable combinations, RAD-001 perturbs the AKT pathway in vitro. The unique combination of fluvastatin and an m-TOR inhibitor was synergistic in both cell lines. These effects were independent of whether or not human plasma was used in the assay system. These studies suggest several novel combinations of agents that need to be evaluated in the management of leukemia.