Increased copy number involving chromosome 3q26 is a frequent and early event in cancers of the ovary, lung, head and neck, cervix, and BRCA1 positive and basal breast cancers. The p110A catalytic subunit of phosphoinositide-3-kinase (PI3KCA) and protein kinase CI (PKCI) have previously been shown as functionally deregulated by 3q copy number increase. High-resolution array comparative genomic hybridization of 235 high-grade serous epithelial ovarian cancers using contiguous bacterial artificial chromosomes across 3q26 delineated an f2 Mb-wide region at 3q26.2 encompassing PDCD10 to MYNN (chr3:168722613-170908630). Ecotropic viral integration site-1 (EVI1) and myelodysplastic syndrome 1 (MDS1) are located at the center of this region, and their DNA copy number increases are associated with at least 5-fold increased RNA transcript levels in 83% and 98% of advanced ovarian cancers, respectively. Moreover, MDS1/EVI1 and EVI1 protein levels are increased in ovarian cancers and cancer cell lines. EVI1 and MDS1/EVI1 gene products increased cell proliferation, migration, and decreased transforming growth factor-B-mediated plasminogen activator inhibitor-1 promoter activity in ovarian epithelial cells. Intriguingly, the increases in EVI1 DNA copy number and MDS1/EVI1 transcripts are associated with improved patient outcomes, whereas EVI1 transcript levels are associated with a poor patient survival. Thus, the favorable patient prognosis associated with increased DNA copy number seems to be as a result of highlevel expression of the fusion transcript MDS1/EVI1. Collectively, these studies suggest that MDS1/EVI1 and EVI1, previously implicated in acute myelogenous leukemia, contribute to the pathophysiology of epithelial ovarian cancer.
Substances (for example, serum proteins or meconium) that interfere with the activity of pulmonary surfactant in vitro may also be important in the pathogenesis or progression of acute lung injury. Addition of polymers such as dextran or polyethylene glycol (PEG) to surfactants prevents and reverses surfactant inactivation. The purpose of this study was to find out whether surfactant/polymer mixtures are more effective for treating one form of acute lung injury than is surfactant alone. Acute lung injury in adult rats was created by tracheal instillation of human meconium. Injured animals, which were anesthetized, paralyzed, and ventilated with 100% oxygen and not treated with surfactant mixtures, remained hypoxic and required high ventilator pressures to maintain Pa(CO(2)) in the normal range over the 3 h of the experiment. Uninjured animals maintained normal values for oxygen and compliance of the respiratory system. The greatest improvement in both oxygenation (178%) and compliance (42%) occurred in animals with lung injury that were treated with Survanta and PEG (versus untreated control animals; p < 0.01), whereas little improvement was found after treatment with Survanta alone. Similar results were found when postmortem pulmonary pressure-volume curves and histology were examined. We conclude that adding PEG to Survanta improves gas exchange, pulmonary mechanics, and histologic appearance of the lungs in a rat model of acute lung injury caused by meconium.
Freeze-fracture transmission electron microscopy shows significant differences in the bilayer organization and fraction of water within the bilayer aggregates of clinical lung surfactants, which increases from Survanta to Curosurf to Infasurf. Albumin and serum inactivate all three clinical surfactants in vitro; addition of the nonionic polymers polyethylene glycol, dextran, or hyaluronic acid also reduces inactivation in all three. Freeze-fracture transmission electron microscopy shows that polyethylene glycol, hyaluronic acid, and albumin do not adsorb to the surfactant aggregates, nor do these macromolecules penetrate the interior water compartments of the surfactant aggregates. This results in an osmotic pressure difference that dehydrates the bilayer aggregates, causing a decrease in the bilayer spacing as shown by small angle x-ray scattering and an increase in the ordering of the bilayers as shown by freeze-fracture electron microscopy. Small angle x-ray diffraction shows that the relationship between the bilayer spacing and the imposed osmotic pressure for Curosurf is a screened electrostatic interaction with a Debye length consistent with the ionic strength of the solution. The variation in surface tension due to surfactant adsorption measured by the pulsating bubble method shows that the extent of surfactant aggregate reorganization does not correlate with the maximum or minimum surface tension achieved with or without serum in the subphase. Albumin, polymers, and their mixtures alter the surfactant aggregate microstructure in the same manner; hence, neither inhibition reversal due to added polymer nor inactivation due to albumin is caused by alterations in surfactant microstructure.
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