Receptor tyrosine kinase Axl is required for resistance of leukemic cells to FLT3-targeted therapy in acute myeloid leukemia.

In acute myeloid leukemia (AML), about 25-30% of patients harbor a constitutively active receptor tyrosine kinase (RTK) FLT3 encoded by a FLT3 allele harboring internal tandem duplication (FLT3-ITD) mutation. The presence of FLT3-ITD correlates with poor prognosis in AML and it makes FLT3 an attractive therapeutic target in AML. Unfortunately, to date small-molecule inhibitors of FLT3 have resulted in only partial and transient clinical responses with residual leukemic blasts resistant to FLT3 inhibitors detected in blood or bone marrow. In this study, we investigated whether the RTK Axl is responsible for resistance of FLT3-ITD(+) AML cells to PKC412 and AC220, FLT3 inhibitors currently under clinical trials for FLT3-ITD(+) AML patients. Upon treatment with PKC412 or AC220, phosphorylation of Axl was significantly enhanced in the FLT3-ITD(+) MV4-11 AML cell line and in primary blasts from a FLT3-ITD(+) AML patient. Consistently, a PKC412-resistant AML cell line and PKC412-resistant primary blasts from FLT3-ITD(+) AML patients had significantly higher levels of constitutively phosphorylated Axl and total Axl when compared with a PKC412-sensitive AML cell line and PKC412-sensitive primary blasts from FLT3-ITD(+) AML patients. We also found that resistance of AML cells against the FLT3 inhibitor PKC412 and AC220 was substantially diminished by the inhibition of Axl via a small-molecule inhibitor TP-0903, a soluble receptor Axl fusion protein Axl-Fc or knockdown of Axl gene expression by shRNA. Collectively, our study suggests that Axl is required for resistance of FLT3-ITD(+) AML cells against the FLT3 inhibitor PKC412 and AC220, and that inhibition of Axl activation may overcome resistance to FLT3-targeted therapy in FLT3-ITD(+) AML.

A randomised controlled trial comparing incentive spirometry with the Acapella® device for physiotherapy after thoracoscopic lung resection surgery.

Lung resection surgery has been associated with numerous postoperative complications. Seventy-eight patients scheduled for elective video-assisted thoracoscopic lung resection were randomly assigned to receive standard postoperative care with incentive spirometry or standard care plus positive vibratory expiratory pressure treatment using the Acapella(®) device. There was no significant difference between incentive spirometry and the Acapella device in the primary outcome, forced expiratory volume in 1 s, on the third postoperative day, mean (SD) 53% (16%) vs 59% (18%) respectively, p = 0.113. Patients treated with both devices simultaneously found incentive spirometry to be less comfortable compared with the Acapella device, using a numeric rating scale from 1 to 5 with lower scores indicating higher comfort, median (IQR [range]) 3 (2-3 [2-4]) vs 1 (1-2 [1-3]) respectively, p < 0.001. In addition, 37/39 patients (95%) stated a clear preference for the Acapella device. Postoperative treatment with the Acapella device did not improve pulmonary function after thoracoscopic lung resection surgery compared with incentive spirometry, but it may be more comfortable to use.

MR traceable delivery of p53 tumor suppressor gene by PEI-functionalized superparamagnetic iron oxide nanoparticles.

Cancer gene therapy involves the replacement of missing or altered genes with healthy ones. In this paper, we have proposed tumor suppressor gene-carrying superparamagnetic iron oxide nanoparticles (SPIONs) for anti-cancer gene therapy. Thermally crosslinked SPIONs (TCL-SPIONs) were conjugated with branched polyethylenimine (PEI 1800 Da) by EDC-NHS chemistry for p53 plasmid DNA delivery. The morphology of the bPEI conjugated TCL-SPIONs (bPEI-TCL-SPION) and pDNA-loaded bPEI-TCL-SPION nanoparticles was measured using transmission electron microscopy (TEM). The particle sizes of the pDNA-loaded bPEI-TCL-SPION nanoparticles were also confirmed by dynamic light scattering, and ranged from 100 to 130 nm, depending on the molar charge ratio. The fluorescently labeled pDNA was complexed with bPEI-TCL-SPION and its intracellular internalization was investigated using confocal microscopy. The p53 plasmid-loaded bPEI-TCL-SPION nanoparticles achieved significantly higher p53 tumor suppressor gene expression and cellular viability compared to positive controls. The expressed wild-type p53 protein suppressed tumor cell proliferation as compared to the mutant control. When transgene expression of the p53 tumor suppressor gene was evaluated at the mRNA level and quantified using real-time PCR, the results were highly dependent on the molar charge ratio (N/P) as well as the cancer cell type. SPIONs internalized within cancer cells were tracked by magnetic resonance (MR) imaging. It was concluded that bPEI-TCL-SPION could be used as efficient gene delivery carriers that can be tracked by MR imaging.

Oesophagography and oesophagoscopy are not necessary in patients with spontaneous pneumomediastinum.

BACKGROUND: Because the condition is rare, the proper assessment of spontaneous pneumomediastinum (SPM) remains controversial. The purpose of this study was to determine whether additional oesophageal investigations beyond chest x ray and chest computed tomography (CT) scan are necessary for the diagnosis of SPM. METHODS: The medical records of 25 patients diagnosed and treated for SPM from March 1986 to December 2007 were retrospectively reviewed. RESULTS: There were 22 men and 3 women, with a median age of 19 years (range 15-57 years). All patients received chest x rays, which revealed air shadows within the mediastinum or subcutaneous emphysema in 24 patients. Twenty-two patients underwent chest CT scans, which showed pneumomediastinum in all cases. Oesophagography was performed in 14 patients and oesophagoscopy in three. All oesophagographies and oesophagoscopies were clear. Despite conservative treatment, no patients developed mediastinitis or complications associated with oesophageal injury. CONCLUSIONS: Chest x ray and CT scan are sufficient to diagnose SPM. Additional diagnostic assessments such as oesophagography and oesophagoscopy are not necessary in patients without evidence of mediastinitis or a history of oesophageal injury.

Peptide-modified vectors for nucleic acid delivery to neurons.

Neuron-targeted nucleic acid delivery systems are important technologies for realizing the potential of gene therapy for nervous system disorders. However, neurons are difficult cells to transfect using non-viral vectors due in part to the specific and unique delivery challenges present in these cells. We have investigated several bioactive peptides for their ability to assist in overcoming delivery barriers in mammalian cells. We summarize here our recent progress in developing and applying peptide-modified polycations for nucleic acid delivery. In addition, we present data demonstrating the potential of using multicomponent, peptide-modified polycations for nucleic acid delivery to neurons.

Phase II study of concurrent chemoradiotherapy with capecitabine and cisplatin in patients with locally advanced squamous cell carcinoma of the head and neck.

We aimed to evaluate the efficacy and safety of concurrent chemoradiotherapy with capecitabine and cisplatin in patients with locally advanced squamous cell carcinoma of the head and neck (SCCHN). In total, 37 patients with stage III or IV SCCHN were enrolled on the study. The chemotherapy consisted of two cycles of intravenous cisplatin of 80 mg m(-2) on day 1 and oral capecitabine 825 mg m(-2) twice daily from day 1 to day 14 at 3-week intervals. The radiotherapy (1.8-2.0 Gy 1 fraction day(-1) to a total dose of 70-70.2 Gy) was delivered to the primary tumour site and neck. The primary tumour sites were as follows: oral cavity (n=6), oropharynx (n=11), hypopharynx (n=8), larynx (n=3), nasopharynx (n=6), and paranasal sinus (n=3). After the chemoradiotherapy, 29 complete responses (78.4%) and 6 partial responses (16.2%) were confirmed. Grade 3 or 4 neutropenia occurred only in two patients, plus grade 3 febrile neutropenia was observed only in one patient. At a median follow-up duration of 19.8 months, the estimated overall survival and progression-free survival rate at 2-year was 76.8 and 57.9%, respectively. Concurrent chemoradiotherapy with capecitabine and cisplatin was found to be well tolerated and effective in patients with locally advanced SCCHN.

A case report: isolated a heavy chain monoclonal gammopathy in a patient with polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy and skin change syndrome.

A 45-year-old South-Korean man presented with abdominal distension, progressive paresthesia and motor weakness of both lower extremities. Our case was identified as polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy and skin change (POEMS) syndrome based on diagnostic criteria. Circulating M components of POEMS syndrome consist mainly of IgG or IgA-lambda and rarely IgM-lambda, IgG-kappa or isolated light chains. In this case, the M-band on serum protein electrophoresis and isolated IgA heavy chain on serum immunofixation electrophoresis were demonstrated, but there was no abnormal light chain. We suggest that this case may be associated with a pattern of abnormal secretion of monoclonal protein or a coincidence of a heavy chain disease in POEMS syndrome, even though the latter possibility may be very rare.

Visualization of transfection of hepatocytes by galactosylated chitosan-graft-poly(ethylene glycol)/DNA complexes by confocal laser scanning microscopy.

Dual-labeled galactosylated chitosan-graft-poly(ethylene glycol) (PEG) (GCP)/DNA complexes were prepared and their hepatocyte-specific delivery and cellular distribution were investigated by confocal laser scanning microscopy (CLSM). The complexes were transfected into hepatocyte through specific interaction of galactose moiety of the GCP and asialoglycoprotein receptors (ASGPR) of the hepatocytes. The GCP/DNA complexes taken up by the hepatocytes were rapidly released into the cytoplasm, but nuclear trafficking of the released complexes was slow and rate-limiting process. The more efficient transfection of the complex occurred in the human-derived HepG2 cells than in primary hepatocytes.

Galactosylated chitosan (GC)-graft-poly(vinyl pyrrolidone) (PVP) as hepatocyte-targeting DNA carrier. Preparation and physicochemical characterization of GC-graft-PVP/DNA complex (1).

Galactosylated chitosan was conjugated with poly(vinyl pyrrolidone) (PVP) as a hydrophilic group. The complex formation of GC-graft-PVP (GCPVP)/DNA complexes was confirmed by agarose gel electrophoresis. The morphology of the complex observed by atomic force microscopy had a compact and spherical shape, around 40 nm particle sizes at a charge ratio of 3. The binding strength of GCPVP 10K/DNA complex measured by ethidium bromide binding assay was superior to that of the GCPVP 50K/DNA one, probably attributable to its higher flexibility due to the smaller size, whereas the DNase I protection of GCPVP 10K/DNA complex was inferior to that of the GCPVP 50K/DNA one. This indicated that effective complex formation required both higher binding strength and minimal molecular weight of polycation enough to induce the condensation of DNA. The DNA-binding property of GCPVP mainly depended on the molecular weight of chitosan and composition of PVP.

Galactosylated chitosan-graft-poly(ethylene glycol) as hepatocyte-targeting DNA carrier.

Lactobionic acid bearing galactose group was coupled with chitosan for liver specificity, and poly(ethylene glycol) (PEG) was grafted to galactosylated chitosan (GC) for stability in water and enhanced cell permeability. Complex formation of galactosylated chitosan-graft-PEG (GCP)/DNA complexes was confirmed by agarose gel electrophoresis. Compared to GC/DNA complex, the stability of GCP/DNA complex could be enhanced. Particle sizes of GCP/DNA complexes decreased as the charge ratio of GCP to DNA increased and had a minimum value around 27 nm at the charge ratio of 5. Conformational change of DNA did not occur after complex formation with GCP compared to conformation of DNA itself. GCP/DNA complexes were only transfected into Hep G2 having asialoglycoprotein receptors (ASGR), indicative of specific interaction of ASGR on cells and galactose ligands on GCP.

NAD+ inhibits the self-splicing of the group I intron.

We investigated the effects of the coenzyme NAD+ (nicotinamide adenine dinucleotide) and its analogs on the self-splicing of primary transcripts of the phage T4 thymidylate synthase gene (td). Of all the nicotinamide coenzymes and analogs tested, NADP+ was the strongest inhibitor, with a potency approximately threefold that of NAD+. Kinetic analysis demonstrated that NAD+ acts as a mixed type noncompetitive inhibitor for the td intron RNA with a K(i) of 4.1 mM. The splicing specificity inhibition by NAD+ is predominantly due to changes in Km and kcat, and was Mg2+ concentration dependent. The results suggest that both the ADP and nicotinamide moieties are the key structural features in NAD+ responsible for the inhibition of splicing.

Molecular cloning and characterization of a novel regulator of G-protein signaling from mouse hematopoietic stem cells.

A novel regulator of G-protein signaling (RGS) has been isolated from a highly purified population of mouse long-term hematopoietic stem cells, and designated RGS18. It has 234 amino acids consisting of a central RGS box and short divergent NH(2) and COOH termini. The calculated molecular weight of RGS18 is 27,610 and the isoelectric point is 8.63. Mouse RGS18 is expressed from a single gene and shows tissue specific distribution. It is most highly expressed in bone marrow followed by fetal liver, spleen, and then lung. In bone marrow, RGS18 level is highest in long-term and short-term hematopoietic stem cells, and is decreased as they differentiate into more committed multiple progenitors. The human RGS18 ortholog has a tissue-specific expression pattern similar to that of mouse RGS18. Purified RGS18 interacts with the alpha subunit of both G(i) and G(q) subfamilies. The results of in vitro GTPase single-turnover assays using Galpha(i) indicated that RGS18 accelerates the intrinsic GTPase activity of Galpha(i). Transient overexpression of RGS18 attenuated inositol phosphates production via angiotensin receptor and transcriptional activation through cAMP-responsive element via M1 muscarinic receptor. This suggests RGS18 can act on G(q)-mediated signaling pathways in vivo.

Effect of cilostazol on the neuropathies of streptozotocin-induced diabetic rats.

OBJECTIVES: This study examined the effect of cilostazol, a potent phosphodiesterase inhibitor, on the progression of neuropathies associated with streptozotocin-induced diabetes mellitus in Sprague-Dawley rats. METHODS: Eight weeks after streptozotocin treatment, a pelleted diet containing 0.03% cilostazol (15 mg/kg body weight) was given for four weeks. Body weight, blood glucose level, motor nerve conduction velocity (MNCV), myelinated fiber density and size distribution of sciatic nerves were compared between age-matched normal rats (Group 1), control diabetic rats (Group 2) and cilostazol-treated diabetic rats (Group 3). RESULTS: Body weight was significantly reduced and blood glucose level was significantly increased in diabetic rats (Group 2 and 3) compared to normal rats. MNCV and cAMP content of sciatic nerves were significantly reduced in diabetic rats 12 weeks after streptozotocin treatment. Myelinated fiber size and density were also significantly reduced, and thickening of the capillary walls and duplication of the basement membranes of the endoneural vessels were observed in the diabetic rats. Whereas both body weight and blood glucose level of Group 3 did not differ significantly from those of Group 2, cilostazol treatment significantly increased MNCV and cAMP content of sciatic nerves in Group 3 but not to the levels observed in Group 1. MNCV positively correlated with cAMP content of sciatic nerves (r = 0.86; p < 0.001). Cilostazol treatment not only restored myelinated fiber density and size distribution but reversed some of the vascular abnormalities. CONCLUSION: These findings suggest that a reduced cAMP content in motor nerves may be involved in the development of diabetic neuropathy, and that cilostazol may prevent the progression of diabetic neuropathy by restoring functional impairment and morphological changes of peripheral nerves.

Analysis of induced sputum to examine the effects of inhaled corticosteroid on airway inflammation in children with asthma.

BACKGROUND: Analysis of induced sputum can be performed safely in children with asthma and is useful for both cellular and biochemical markers of inflammation. Glucocorticosteroid inhalation has become the first line therapy for chronic asthma by suppressing airway inflammation, which produces the decrease of bronchial hyperreactivity and reduces the number of eosinophil in bronchial submucosa. OBJECTIVE: To determine the characteristics of the inflammatory cells and their markers in sputum and to examine the pharmacokinetic effects of glucocorticoid within 3 hours after inhalation therapy on FEV1 and sputum inflammatory indices in children with clinically defined chronic asthma. METHODS: Thirty subjects with asthma included 14 current symptomatic asthmatics and 14 normal controls inhaled 4.5% hypertonic saline for 10 minutes by nebulizer. The expectorated sputum were collected from all asthmatics before and 3 hours after corticosteroid inhalation for children with asthma and were reduced by dithiotreitol. Total cell counts and differentials were determined. ECP was measured by CAP system. Interleukin-5, GM-CSF and albumin were measured by double sandwich ELISA. RESULTS: The mean eosinophil percentage and ECP in induced sputum of asthmatics were significantly higher than that of controls. The induced sputum samples obtained after glucocorticoid inhalation showed a significant reduction in mean eosinophil percentage, but FEV1, IL-5, GM-CSF, albumin, and ECP values were not significantly decreased. CONCLUSION: The present results in induced sputum may be interpreted to reflect direct steroid action on airways and lack of effect on bone marrow effectors at 3 hours after glucocorticoid inhalation.

Over-expression of urokinase receptor in human epidermoid-carcinoma cell line (HEp3) increases tumorigenicity on chorio-allantoic membrane and in severe-combined-immunodeficient mice.

Using chorio-allantoic membranes (CAMs) of chick embryos and severe-combined-immunodeficient (SCID) mice, we investigated the effects of urokinase-type plasminogen-activator receptor (u-PAR) over-expression on the process of invasion and tumorigenicity. By the transfection of u-PAR cDNA, 3 u-PAR-over-expressing clones expressing 1.6- to 4.6-fold more u-PAR mRNA than parent cells were obtained from a human epidermoid-carcinoma cell line, HEp3, that expresses urokinase-type plasminogen activator (u-PA) and u-PAR. All the u-PAR-over-expressing clones showed greater invasiveness (13 to 29%) than that of parent HEp3 cells on CAMs. Immunohistochemistry revealed densely stained u-PAR-positive cells near the margin of the tumor, where a u-PAR-over-expressing clone, designated SM-3, was invading thickened fibrous tissue on CAMs. Three u-PAR-overexpressing clones formed larger tumors (>40 mm3) than did parent HEp3 cells on CAMs. Moreover, when the u-PAR-overexpressing clone (SM-3) was injected s.c. into the back of the SCID mice it produced a larger tumor volume than the control (HEp3) and down-regulated (AS-2) clones and significantly shortened the survival of SCID mice. These results demonstrate that increased u-PAR expression is an important factor in determining the malignant phenotype that makes cancer cells more invasive and tumorigenic.

Co-expression of urokinase-type plasminogen activator and its receptor in human gastric-cancer cell lines correlates with their invasiveness and tumorigenicity.

The expression of urokinase-type plasminogen activator (u-PA), its receptor (u-PAR) and metalloproteases activity were analyzed in 4 human gastric-cancer cell lines (AGS, Hs746T, SNU-1, and SNU-5), in an attempt to relate these activities to their invasive potential and tumorigenicity on the modified chorioallantoic membranes (CAM) of chick embryos. Only 1 of the 4 cell lines tested, Hs746T, expressed both u-PA and u-PAR as well as MMP-2, but not MMP-9. This cell line was both tumorigenic and highly invasive (51.3 +/- 13.1%) on a modified CAM. Its invasive capacity was comparable with that of a highly malignant human epidermoid-carcinoma cell line (HEp3), which usually showed 40 to 50% invasiveness. The 3 other cell lines all produced MMP-2 and MMP-9, but only AGS showed moderate invasiveness (24.2 +/- 8.8%). While antibodies to u-PA were significantly effective in reducing CAM invasiveness of Hs746T cells by approximately 40%, the invasiveness of the t-PA-expressing AGS cell line was not affected by anti-t-PA antibodies. These results suggest that when one of the components of the u-PA/u-PAR system (the enzyme and/or the receptor) is not produced and u-PA/u-PAR-dependent cell-surface proteolytic activity is thereby diminished, the malignant phenotype that can be determined by tumorigenicity and invasion of connective tissue on a CAM is compromised. Production of both type-IV collagenases (MMP-2 and MMP-9) cannot offset this deficiency.

Reactivity of antibodies against 10-amino acid residue and pro-domain of stromelysin-3.

Stromelysin-3 (ST3) has two highly conserved domains in the pro-domain. In particular, an unusual 10-amino acid residue sandwiched between the pro-domain and the catalytic domain of ST3 exists in ST3 but not in other matrix metalloproteinases (MMPs). To specifically detect ST3 expression in human tumors, we have made two kinds of ST3-specific polyclonal antibodies. One was raised against the synthetic 10-amino acid residue (88GLSARNRQKR97) specific to ST3, and the other against recombinant ST3 pro-domain (62APATQEAPRPASSLRPPRCGVPDPSDGLSARNRQKR97) containing the decapeptide and PRCGVPD sequence obtained by expression in Escherichia coli. Two protein species, 59 kDa and 45 kDa which were consistent with those expected for pro-ST3 and the mature form of ST3, were specifically detected in 100-fold concentrated conditioned media of fetal lung fibroblast by Western blot analysis. Immunohistochemical staining indicated that in infiltrating ductal breast carcinoma and squamous cell carcinoma of the uterine cervix, reactivity of those antibodies was found not only in fibroblastic cells surrounding cancer cells but also in neoplastic cells. However, reactivity of two ST3 antibodies was inhibited by excess of the synthetic peptide (10-amino acid residue) not only in fibroblastic cells but also in neoplastic cells. These findings suggest that antibodies against the ST3 specific region may cross react with the recently known membrane type-metalloproteinase (MT-MMP), which have RXKR sequences between the pro- and catalytic domain.

Domains of phosphatase inhibitor-2 involved in the control of the ATP-Mg-dependent protein phosphatase.

Inhibitor-2 (I-2) inhibits the free catalytic subunit of type 1 phosphatase (CS1) and controls the cyclic inactivation/activation of CS1 in the ATP-Mg-dependent protein phosphatase complex. We report here the effect of mutations on these two properties of I-2. Substitution of Thr-72 with Ala, Asp, or Glu generated complexes with CS1 that could not be activated. Mutation of Ser-86 did not affect activation by glycogen synthase kinase-3 (GSK-3) alone but impaired synergistic activation by casein kinase II and GSK-3. Mutations in the region between Thr-72 and Ser-86 did not alter the inhibitory potency of I-2 but prevented complete inactivation of CS1. A mutant without the 35 NH2-terminal residues exhibited an IC50 for CS1 200-fold higher than that of wild-type I-2. However, it formed an inactive phosphatase complex with CS1, which was activated by GSK-3. A mutant with the 59 COOH-terminal residues deleted retained full inhibitory activity and formed an inactive complex that could not be activated by GSK-3. We conclude that the NH2-terminal region of I-2 is involved in inhibition, that the sequence between Thr-72 and Ser-86 is necessary for the conversion of CS1 from an active to an inactive conformation, and that the COOH terminus is required for activation by GSK-3. Thus, different functional domains of I-2 may interact with distinct regions of CS1.

Serine/threonine protein phosphatases in the control of cell function.

Reversible protein phosphorylation is a fundamental mechanism by which many biological functions are regulated. Achievement of such control requires the coordinated action of the interconverting enzymes, the protein kinases and protein phosphatases. By comparison with protein kinases, a limited number of protein phosphatase catalytic subunits are present in the cell, which raises the question of how such a small number of dephosphorylating enzymes can counterbalance the action of the more numerous protein kinases. In mammalian cells, four major classes of Ser/Thr-specific phosphatase catalytic subunits have been identified, comprising two distinct gene families. The high degree of homology among members of the same family, PP1, PP2A and PP2B, and the high degree of evolutionary conservation between organisms as divergent as mammals and yeast, implies that these enzymes are involved in fundamental cell functions. Type 1 enzymes appear to acquire specificity by association with targeting regulatory subunits which direct the enzymes to specific cellular compartments, confer substrate specificity and control enzyme activity. In spite of the progress made in determining the structure of the PP2A subunits, very little is known about the control of this activity and about substrate selection. Recent studies have unravelled a significant number of regulatory subunits. The potential existence of five distinct B or B-related polypeptides, some of which are present in multiple isoforms, two A and two C subunit isoforms, raises the possibility that a combinatorial association could generate a large number of specific PP2A forms with different substrate specificity and/or cellular localization. Moreover, biochemical, biological and genetic studies all concur in suggesting that the regulatory subunits may play an important role in determining the properties of the Ser/Thr protein phosphatases and hence their physiological functions.