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.

Quantification of hyaluronan (HA) using a simplified fluorophore-assisted carbohydrate electrophoresis (FACE) procedure.

Hyaluronan (HA) exhibits numerous important roles in physiology and pathologies, and these facts necessitate an ability to accurately and reproducibly measure its quantities in tissues and cell cultures. Our group previously reported a rigorous and analytical procedure to quantify HA (and chondroitin sulfate, CS) using a reductive amination chemistry and separation of the fluorophore-conjugated, unsaturated disaccharides unique to HA and CS on high concentration acrylamide gels. This procedure is known as fluorophore-assisted carbohydrate electrophoresis (FACE) and has been adapted for the detection and quantification of all glycosaminoglycan types. While this previous FACE procedure is relatively straightforward to implement by carbohydrate research investigators, many nonglycoscience laboratories now studying HA biology might have difficulties establishing this prior FACE procedure as a routine assay for HA. To address this need, we have greatly simplified our prior FACE procedure for accurate and reproducible assessment of HA in tissues and cell cultures. This chapter describes in detail this simplified FACE procedure and, because it uses an enzyme that degrades both HA and CS, investigators will also gain additional insight into the quantities of CS in the same samples dedicated for HA analysis.

Exploratory study on the effect of osteoactivin on muscle regeneration in a rat volumetric muscle loss model.

Wounds causing extensive injury loss of muscle, also known as volumetric muscle loss (VML), are frequently associated with high-energy civilian trauma and combat-related extremity injuries. Currently, no effective clinical therapy is available for promoting de novo muscle tissue regeneration to restore muscle function following VML. Recent studies have shown evidence that osteoactivin (OA), a transmembrane glycoprotein, has the ability to prevent skeletal muscle atrophy in response to denervation. Therefore the objective of this study is to investigate the potential regenerative effect of OA embedded and delivered via a cross-linked gelatin hydrogel within a volumetric tibialis anterior muscle defect in a rat model. After 4 weeks, however, no evidence for muscle formation was found in defects treated with either low (5 µg/ml) or high (50 µg/ml) OA. It is possible that a different delivery scaffold, delivery kinetics, or OA concentration may have yielded an alternate outcome, or it is also possible that the spaciostructural environment of VML, or the local (versus systemic) delivery of OA, simply does not support any potential regenerative activity of OA in VML. Together with prior work, this study demonstrates that an efficacious and scalable therapy for regenerating muscle volume and function in VML remains a veritable clinical challenge worthy of continued future research efforts.

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.