Granulocyte Transfusions in Patients with Chronic Granulomatous Disease Undergoing Hematopoietic Cell Transplantation or Gene Therapy

Journal of Clinical Immunology - Granulocyte transfusions are sometimes used as adjunctive therapy for the treatment of infection in patients with chronic granulomatous disease (CGD). However,...     

Ca2+-mediated ascorbate release from coronary artery endothelial cells

1.--The addition of Ca(2+) ionophore A23187 or ATP to freshly isolated or cultured pig coronary artery endothelial cells (PCEC) potentiated the release of ascorbate (Asc). Cultured PCEC were used to characterize the Ca(2+)-mediated release. An increase in Ca(2+)-mediated Asc release was observed from PCEC preincubated with Asc, Asc-2-phosphate or dehydroascorbic acid (DHAA). 2.--The effects of various ATP analogs and inhibition by suramin were consistent with the ATP-induced release being mediated by P2Y2-like receptors. 3.--ATP-stimulated Asc release was Ca(2+)-mediated because (a) ATP analogs that increased Asc release also elevated cytosolic [Ca(2+)], (b) Ca(2+) ionophore A23187 and cyclopiazonic acid stimulated the Asc release, (c) removing extracellular Ca(2+) and chelating intracellular Ca(2+)inhibited the ATP-induced release, and (d) inositol-selective phospholipase C inhibitor U73122 also inhibited this release. 4.--Accumulation of Asc by PCEC was examined at Asc concentrations of 10 microM (Na(+)-Asc symporter not saturated) and 5 mM (Na(+)-Asc symporter saturated). At 10 microM Asc, A23187 and ATP caused an inhibition of Asc accumulation but at 5 mM Asc, both the agents caused a stimulation. Substituting gluconate for chloride did not affect the basal Asc uptake but it abolished the effects of A23187. 5.--PCEC but not pig coronary artery smooth muscle cells show a Ca(2+)- mediated Asc release pathway that may be activated by agents such as ATP.     

Mixed micelles of PEG(2000)-DSPE and vitamin-E TPGS for concurrent delivery of paclitaxel and parthenolide: enhanced chemosenstization and antitumor efficacy against non-small cell lung cancer (NSCLC) cell lines

Concurrent combination of chemotherapeutic drugs is a promising alternative to single-agent therapies in cancer. In the present study, paclitaxel and parthenolide were loaded into mixed micelles and tested against taxol sensitive (A549) and resistant (A549-T24) NSCLC cell lines. Combination chemotherapy was further evaluated by isobologram analyses and combination index calculations. Drugs were loaded into micelles by the film casting method using PEG(2000)-DSPE and vitamin E-TPGS. Micelle characterization studies included the determination of particle size, encapsulation efficiency, in vitro release kinetics, as well as 1H NMR analysis. The in vitro release of both drugs was slower from the mixed micelles, which maintained an encapsulation efficiency >95% and chemical stability over a storage period of 45 days. The IC50 of paclitaxel and parthenolide determined by MTT assay were 108.6nM and 21μM, respectively, while the combination had an IC50 of 64.15nM in A549 cells. In the taxol resistant cell lines, the IC50 values of paclitaxel and parthenolide were 233nM and 32μM, respectively, while the combination had an IC(50) of 128nM. The efficacy of paclitaxel and parthenolide against both cell lines significantly increased when the drugs were coencapsulted in mixed micelles. Mixed micelles caused 79% cell death, which was significantly higher than the 46% cell death caused by the drugs in solution against taxol sensitive cell lines. In taxol resistant cell lines, the cell death caused by mixed micelles was 70% as compared to 45% cell death caused by un-encapsulated drugs. Co-encapsulation of parthenolide with paclitaxel in mixed micelles increased the anticancer activity of paclitaxel against resistant and sensitive lung cancer cell lines.     

The chemokine CXCL14 (BRAK) stimulates activated NK cell migration: implications for the downregulation of CXCL14 in malignancy

OBJECTIVE: The primary function of chemokines is the regulation of leukocyte trafficking by stimulating directional chemotaxis. The chemokine CXCL14 (BRAK) is highly expressed in all normal tissues, but is not expressed in most malignant tissues. The chemotactic activity of CXCL14 has been difficult to characterize. Recently it was reported that CXCL14 is a chemoattractant for activated monocytes and immature dendritic cells. Given that CXCL14 is downregulated upon transition to malignancy, we sought to characterize whether CXCL14 might play a role in NK cell chemotaxis. METHODS: Human natural killer (NK) cells were isolated from buffy coats obtained from normal volunteers and were activated with lymphocyte conditioned media, IL-2, and ionomycin. Standard transwell chemotaxis assays, proliferation assays, and chromium release cell cytotoxicity assays were performed. RESULTS: CXCL14 was found to stimulate migration of activated human NK cells in transwell chemotaxis assays by 1.4-fold. Similarly, it increased migration of an IL-2-dependent natural killer leukemia (NKL) cell line by 1.9-fold. Antisera against CXCL14 or pertussis toxin blocked this chemotactic effect. However, CXCL14 did not affect the proliferation or cytotoxic activity of normal human NK cells. CXCL14 also stimulated the chemotaxis of immature monocyte-derived dendritic cells. CONCLUSIONS: CXCL14 may play a role in the trafficking of NK cells to sites of inflammation or malignancy. In addition, the downregulation of the expression of CXCL14 might be an important step in successful oncogenesis to prevent NK immune surveillance of the malignancy.     

Paclitaxel loaded PEG5000–DSPE micelles as pulmonary delivery platform: Formulation characterization, tissue distribution, plasma pharmacokinetics, and toxicological evaluation

The objective of the present study was to evaluate the potential of paclitaxel loaded micelles fabricated from PEG₅₀₀₀–DSPE as a sustained release system following pulmonary delivery. PEG₅₀₀₀–DSPE micelles containing paclitaxel were prepared by solvent evaporation technique followed by investigation of in vitro release of paclitaxel in lung simulated fluid. Tissue distribution and plasma pharmacokinetics of the PEG–lipid micelles after intratracheal and intravenous administrations were investigated in addition to intratracheally administered taxol. Finally, toxicological profile of PEG₅₀₀₀–DSPE was investigated. Paclitaxel was successfully formulated in PEG–lipid micelles with encapsulation efficiency of 95%. The PEG–lipid micelles exhibited a sustained release behavior in the simulated lung fluid. Intratracheally administered polymeric micellar paclitaxel showed highest accumulation of paclitaxel in the lungs with AUC_0–12 in lungs being 45-fold higher than intravenously administered formulation and 3-fold higher than intratracheally delivered taxol. Paclitaxel concentration in other non-targeted tissues and plasma were significantly lower as compared to other groups. Furthermore, toxicity studies showed no significant increase in levels of lung injury markers in PEG₅₀₀₀–DSPE treated group as compared to saline-treated group. PEG₅₀₀₀–DSPE micelles delivered intratracheally were able to sustain highest paclitaxel concentrations in lungs for long periods of time, thus apprehending their suitability as pulmonary drug carriers.     

PEG–lipid micelles as drug carriers: physiochemical attributes,formulation principles and biological implication

PEG–lipid micelles, primarily conjugates of polyethylene glycol (PEG) and distearyl phosphatidylethanolamine (DSPE) or PEG–DSPE, have emerged as promising drug-delivery carriers to address the shortcomings associated with new molecular entities with suboptimal biopharmaceutical attributes. The flexibility in PEG–DSPE design coupled with the simplicity of physical drug entrapment have distinguished PEG–lipid micelles as versatile and effective drug carriers for cancer therapy. They were shown to overcome several limitations of poorly soluble drugs such as non-specific biodistribution and targeting, lack of water solubility and poor oral bioavailability. Therefore, considerable efforts have been made to exploit the full potential of these delivery systems; to entrap poorly soluble drugs and target pathological sites both passively through the enhanced permeability and retention (EPR) effect and actively by linking the terminal PEG groups with targeting ligands, which were shown to increase delivery efficiency and tissue specificity. This article reviews the current state of PEG–lipid micelles as delivery carriers for poorly soluble drugs, their biological implications and recent developments in exploring their active targeting potential. In addition, this review sheds light on the physical properties of PEG–lipid micelles and their relevance to the inherent advantages and applications of PEG–lipid micelles for drug delivery.     

The SET domain protein Metnase mediates foreign DNA integration and links integration to nonhomologous end-joining repair

The molecular mechanism by which foreign DNA integrates into the human genome is poorly understood yet critical to many disease processes, including retroviral infection and carcinogenesis, and to gene therapy. We hypothesized that the mechanism of genomic integration may be similar to transposition in lower organisms. We identified a protein, termed Metnase, that has a SET domain and a transposase/nuclease domain. Metnase methylates histone H3 lysines 4 and 36, which are associated with open chromatin. Metnase increases resistance to ionizing radiation and increases nonhomologous end-joining repair of DNA doublestrand breaks. Most significantly, Metnase promotes integration of exogenous DNA into the genomes of host cells. Therefore, Metnase is a nonhomologous end-joining repair protein that regulates genomic integration of exogenous DNA and establishes a relationship among histone modification, DNA repair, and integration. The data suggest a model wherein Metnase promotes integration of exogenous DNA by opening chromatin and facilitating joining of DNA ends. This study demonstrates that eukaryotic transposase domains can have important cell functions beyond transposition of genetic elements.