Invasive phenotype observed in 1,3-bis(2-chloroethyl)-1-nitrosourea—resistant sublines of 9L rat glioma cells: a tumor model mimicking a recurrent malignant glioma

2004 ◽  
Vol 101 (5) ◽  
pp. 826-831 ◽  
Author(s):  
Ryuta Saito ◽  
John Bringas ◽  
Hanna Mirek ◽  
Mitchel S. Berger ◽  
Krys S. Bankiewicz
Keyword(s):  
Drug Resistance ◽  
Tumor Model ◽  
Growth Patterns ◽  
Invasive Growth ◽  
Content Type ◽  
Rat Glioma ◽  
Brain Tumor Model ◽  
Fine Print

Object. Chemotherapy is suspected of having an effect on the generation of phenotypical heterogeneity and the development of drug resistance in tumors. Recurrent gliomas feature drug resistance as well as greater invasive growth than original tumors. The authors investigated phenotypical changes in invasion observed in 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU)—resistant sublines of the 9L rat gliosarcoma. Methods. Two established BCNU-resistant sublines, derived from 9L gliosarcoma cells by treating these cells with BCNU in vivo or in vitro, were used in the study. An in vitro examination confirmed the resistance of the cells to BCNU treatment. The cells were implanted into the striatum of Fisher 344 rats, and histological examinations were performed to compare the growth patterns of the resultant tumors. A new brain tumor model was established by implanting 9L-2 cells in Fisher 344 rats. The 9L-2 and BTRC-19 cells displayed a distinct increase in BCNU resistance compared with the 9L cells. Both BCNU-resistant sublines developed a tumor mass with invasive margins, which is not the case with 9L tumor models. The newly developed 9L-2 tumor model demonstrated 100% tumor uptake with consistent growth patterns. Conclusions. Cells that acquire drug resistance also demonstrated invasive growth. Because the 9L-2 and BTRC-19 cells were derived from 9L cells that had been treated with BCNU in vivo and in vitro, this change in phenotype was likely caused by the drug treatment, which may have implications for chemotherapy of gliomas. The tumor model that developed from the 9L-2 cells can be used as a model of a recurrent glioma, which features drug resistance and invasive growth.

Antitumor effects of antiprogesterones on human meningioma cells in vitro and in vivo

1994 ◽  
Vol 80 (3) ◽  
pp. 527-534 ◽  
Author(s):  
Yasuhiro Matsuda ◽  
Keiichi Kawamoto ◽  
Katsuzo Kiya ◽  
Kaoru Kurisu ◽  
Kazuhiko Sugiyama ◽  
...  
Keyword(s):  
Marked Reduction ◽  
Tumor Volume ◽  
Collagen Gel ◽  
Antitumor Effects ◽  
Histological Changes ◽  
Content Type ◽  
The Relationship ◽  
Fine Print

✓ The presence of the progesterone receptor (PR) in meningioma tissue has been confirmed by previous investigations. Studies have shown that the antiprogesterone drug, mifepristone, is a potent agent that inhibits the growth of cultured meningioma cells and reduces the size of meningiomas in experimental animal models and humans. However, these studies have not fully examined the relationship between the antitumor effects of an antiprogesterone agent and the expression of the PR. The present study examined the antitumor effects of mifepristone and a new potent antiprogesterone agent, onapristone; a correlation between the antitumor effects of these antiprogesterones and the presence of PR's in meningiomas in vitro and in vivo was also investigated. Meningioma tissue surgically removed from 13 patients was used in this study. In the in vitro arm of the study, mifepristone and onapristone exhibited cytostatic and cytocidal effects against cultured meningioma cells, regardless of the presence or absence of PR's; however, three PR-negative meningiomas showed no response to any dose of mifepristone and/or onapristone. In the in vivo arm, meningioma cells, embedded in a collagen gel, were implanted into the renal capsules of nude mice. Antiprogesterone treatment resulted in a marked reduction of the tumor volume regardless of the presence or absence of PR's. No histological changes in the meningioma cells suggestive of necrosis or apoptosis were detected in any of the mice treated with antiprogesterones. These findings suggest that mifepristone and onapristone have an antitumor effect against meningioma cells via the PR's and/or another receptor, such as the glucocorticoid receptor.

scholarly journals Upregulation of the Adhesin Gene EPA1 Mediated by PDR1 in Candida glabrata Leads to Enhanced Host Colonization

mSphere ◽  
2016 ◽  
Vol 1 (2) ◽  
Author(s):  
Luis A. Vale-Silva ◽  
Beat Moeckli ◽  
Riccardo Torelli ◽  
Brunella Posteraro ◽  
Maurizio Sanguinetti ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Epithelial Cells ◽  
Candida Glabrata ◽  
Resistance Mechanism ◽  
Cell Types ◽  
Host Cells ◽  
Regulation Mechanism ◽  
Content Type

ABSTRACT Candida glabrata is an important fungal pathogen in human diseases and is also rapidly acquiring drug resistance. Drug resistance can be mediated by the transcriptional activator PDR1, and this results in the upregulation of multidrug transporters. Intriguingly, this resistance mechanism is associated in C. glabrata with increased virulence in animal models and also with increased adherence to specific host cell types. The C. glabrata adhesin gene EPA1 is a major contributor of virulence and adherence to host cells. Here, we show that EPA1 expression is controlled by PDR1 independently of subtelomeric silencing, a known EPA1 regulation mechanism. Thus, a relationship exists between PDR1, EPA1 expression, and adherence to host cells, which is critical for efficient virulence. Our results demonstrate that acquisition of drug resistance is beneficial for C. glabrata in fungus-host relationships. These findings further highlight the challenges of the therapeutic management of C. glabrata infections in human patients. Candida glabrata is the second most common Candida species causing disseminated infection, after C. albicans. C. glabrata is intrinsically less susceptible to the widely used azole antifungal drugs and quickly develops secondary resistance. Resistance typically relies on drug efflux with transporters regulated by the transcription factor Pdr1. Gain-of-function (GOF) mutations in PDR1 lead to a hyperactive state and thus efflux transporter upregulation. Our laboratory has characterized a collection of C. glabrata clinical isolates in which azole resistance was found to correlate with increased virulence in vivo. Contributing phenotypes were the evasion of adhesion and phagocytosis by macrophages and an increased adhesion to epithelial cells. These phenotypes were found to be dependent on PDR1 GOF mutation and/or C. glabrata strain background. In the search for the molecular effectors, we found that PDR1 hyperactivity leads to overexpression of specific cell wall adhesins of C. glabrata. Further study revealed that EPA1 regulation, in particular, explained the increase in adherence to epithelial cells. Deleting EPA1 eliminates the increase in adherence in an in vitro model of interaction with epithelial cells. In a murine model of urinary tract infection, PDR1 hyperactivity conferred increased ability to colonize the bladder and kidneys in an EPA1-dependent way. In conclusion, this study establishes a relationship between PDR1 and the regulation of cell wall adhesins, an important virulence attribute of C. glabrata. Furthermore, our data show that PDR1 hyperactivity mediates increased adherence to host epithelial tissues both in vitro and in vivo through upregulation of the adhesin gene EPA1. IMPORTANCE Candida glabrata is an important fungal pathogen in human diseases and is also rapidly acquiring drug resistance. Drug resistance can be mediated by the transcriptional activator PDR1, and this results in the upregulation of multidrug transporters. Intriguingly, this resistance mechanism is associated in C. glabrata with increased virulence in animal models and also with increased adherence to specific host cell types. The C. glabrata adhesin gene EPA1 is a major contributor of virulence and adherence to host cells. Here, we show that EPA1 expression is controlled by PDR1 independently of subtelomeric silencing, a known EPA1 regulation mechanism. Thus, a relationship exists between PDR1, EPA1 expression, and adherence to host cells, which is critical for efficient virulence. Our results demonstrate that acquisition of drug resistance is beneficial for C. glabrata in fungus-host relationships. These findings further highlight the challenges of the therapeutic management of C. glabrata infections in human patients.

Efficacy of LY233053, a competitive glutamate antagonist, in experimental central nervous system ischemia

1992 ◽  
Vol 76 (1) ◽  
pp. 106-110 ◽  
Author(s):  
Kenneth P. Madden ◽  
Wayne M. Clark ◽  
Abha Kochhar ◽  
Justin A. Zivin
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Side Effects ◽  
Excitatory Amino Acids ◽  
Neurological Damage ◽  
Content Type ◽  
Glutamate Antagonist ◽  
Fine Print

✓ Antagonists of excitatory amino acids appear to serve a neuroprotective role during ischemic conditions in a variety of in vivo and in vitro models. The usefulness of such agents in the clinical setting, however, may be limited by poor central nervous system (CNS) entry and intolerable side effects. The authors report high efficacy in reducing neurological damage and relatively limited side effects of LY233053, a novel competitive glutamate antagonist, in two models of experimental CNS ischemia in the rabbit.

Tumor-associated neurological dysfunction prevented by lazaroids in rats

1991 ◽  
Vol 74 (1) ◽  
pp. 112-115 ◽  
Author(s):  
Wesley A. King ◽  
Keith L. Black ◽  
Kiyonobu Ikezaki ◽  
Scott Conklin ◽  
Donald P. Becker
Keyword(s):  
Vascular Permeability ◽  
Tumor Model ◽  
Neurological Dysfunction ◽  
Control Group ◽  
Content Type ◽  
Brain Tumor Model ◽  
Walker 256 ◽  
Walker 256 Tumors ◽  
Fine Print ◽  
Better Than

✓ The efficacy of U-74006F and U-78517F in the treatment of blood-tumor barrier permeability and tumor-associated neurological dysfunction was evaluated in a brain-tumor model in rats. U-74006F is a 21-aminosteroid and U-78517F is a 2-methylamino chroman. Rats with stereotactically implanted Walker 256 tumors were treated with methylprednisolone, U-74006F, U-78517F, or vehicle (0.05 N HCl) on Days 6 through 10 following implantation. Neurological function and vascular permeability were assessed on Day 10. Methylprednisolone and U-74006F were equally effective at preventing neurological dysfunction compared to the control group (p < 0.01); U-78517F was slightly less effective than U-74006F and methylprednisolone but was significantly better than vehicle in preventing neurological dysfunction. Delivery of methylprednisolone resulted in a significant decrease in tumor vascular permeability (p < 0.006) while U-74006F and U-78517F had no effect on permeability. This suggests that U-74006F and U-78517F prevented tumor-associated neurological dysfunction by a mechanism other than decreasing permeability in tumor capillaries, and that U-74006F or U-78517F could prove useful in the treatment of brain tumors.

A realistic brain tissue phantom for intraparenchymal infusion studies

2004 ◽  
Vol 101 (2) ◽  
pp. 314-322 ◽  
Author(s):  
Zhi-Jian Chen ◽  
George T. Gillies ◽  
William C. Broaddus ◽  
Sujit S. Prabhu ◽  
Helen Fillmore ◽  
...  
Keyword(s):  
Mr Imaging ◽  
Bromophenol Blue ◽  
Agarose Gel ◽  
Convection Enhanced Delivery ◽  
Content Type ◽  
Force Profile ◽  
The Brain ◽  
Fine Print

Object. The goal of this study was to validate a simple, inexpensive, and robust model system to be used as an in vitro surrogate for in vivo brain tissues in preclinical and exploratory studies of infusion-based intraparenchymal drug and cell delivery. Methods. Agarose gels of varying concentrations and porcine brain were tested to determine the infusion characteristics of several different catheters at flow rates of 0.5 and 1 µl per minute by using bromophenol blue (BPB) dye (molecular weight [MW] ∼690) and gadodiamide (MW ∼573). Magnetic resonance (MR) imaging and videomicroscopy were used to measure the distribution of these infusates, with a simultaneous measurement of infusion pressures. In addition, the forces of catheter penetration and movement through gel and brain were measured. Agarose gel at a 0.6% concentration closely resembles in vivo brain with respect to several critical physical characteristics. The ratio of distribution volume to infusion volume of agarose was 10 compared with 7.1 for brain. The infusion pressure of the gel demonstrated profiles similar in configuration and magnitude to those of the brain (plateau pressures 10–20 mm Hg). Gadodiamide infusion in agarose closely resembled that in the brain, as documented using T1-weighted MR imaging. Gadodiamide distribution in agarose gel was virtually identical to that of BPB dye, as documented by MR imaging and videomicroscopy. The force profile for insertion of a silastic catheter into agarose gel was similar in magnitude and configuration to the force profile for insertion into the brain. Careful insertion of the cannula using a stereotactic guide is critical to minimize irregularity and backflow of infusate distribution. Conclusions. Agarose gel (0.6%) is a useful surrogate for in vivo brain in exploratory studies of convection-enhanced delivery.

Gangliosides: the relevance of current research to neurosurgery

1991 ◽  
Vol 74 (4) ◽  
pp. 606-619 ◽  
Author(s):  
Frank A. Rodden ◽  
Herbert Wiegandt ◽  
Bernard L. Bauer
Keyword(s):  
Nervous System ◽  
Mammalian Cells ◽  
Human Subjects ◽  
Laboratory Animals ◽  
Trophic Effect ◽  
Content Type ◽  
Degree Of Malignancy ◽  
Fine Print

✓ Gangliosides are complex glycolipids found on the outer surface of most cell membranes: they are particularly concentrated in tissues of the nervous system. Gangliosides form part of the immunological identity of mammalian cells and are involved in a variety of cell-surface phenomena such as cell-substrate binding and receptor functions. In tumorous tissue, the ganglioside composition is altered, sometimes in direct proportion to the degree of malignancy. The literature on the glycosphingolipid composition and immunology of intracranial tumors is reviewed. Some gangliosides induce neuritogenesis and exhibit a trophic effect on nerve cells grown in vitro. In vivo, a particular ganglioside, GM1, reduces cerebral edema and accelerates recovery from injury (traumatic and ischemic) to the peripheral and central nervous systems of laboratory animals. Preliminary clinical studies have shown that treatment with gangliosides may have corresponding effects on lesions of the human peripheral nervous system. Gangliosides have not been tested in human subjects with brain injury.

Assessment of brain tumor cell motility in vivo and in vitro

1995 ◽  
Vol 82 (4) ◽  
pp. 615-622 ◽  
Author(s):  
Michael R. Chicoine ◽  
Daniel L. Silbergeld
Keyword(s):  
Brain Tumor ◽  
Cell Motility ◽  
Human Brain Tumor ◽  
Content Type ◽  
Brain Tumor Cells ◽  
Tumor Cell Motility ◽  
Brain Tumor Cell ◽  
Fine Print

✓ Brain tumor dispersal far from bulk tumor contributes to and, in some instances, dominates disease progression. Three methods were used to characterize brain tumor cell motility in vivo and in vitro: 1) 2 weeks after implantation in rat cerebral cortex, single C6 cells labeled with a fluorescent tag had migrated to brain sites greater than 16 mm distant from bulk tumor; 2) time-lapse videomicroscopy of human brain tumor cells revealed motility of 12.5 µm/hr. Ruffling leading edges and pseudopod formation were most elaborate in more malignant cells; 3) an in vitro assay was devised to quantitatively evaluate motility from a region of high cell density to one of lower cell density. Human brain tumor cells were plated in the center of a petri dish, washed, and refed, establishing a 2-cm circular zone of cells in the dish center. Motility was determined by counting cells daily at predetermined distances from the central zone perimeter. Cells were found 1 cm from the perimeter by 24 hours and 3 cm from the perimeter by 4 days. Increasing serum concentration increased motility; however, neither fibronectin nor arrest of cells in the G0 phase by hydroxyurea altered motility. The addition of cytochalasin B to block cytoskeletal assembly prevented cell motility. Motility increased with increased malignancy. Subpopulations of cells were created by clonal amplification of cells that had migrated most rapidly to the dish periphery. Although morphologically indistinguishable when compared to the original cell line from which they were derived, these subpopulations demonstrated significantly increased motility.

scholarly journals Polymorphonuclear Leukocytes Restrict Growth of Pseudomonas aeruginosa in the Lungs of Cystic Fibrosis Patients

2014 ◽  
Vol 82 (11) ◽  
pp. 4477-4486 ◽  
Author(s):  
Kasper N. Kragh ◽  
Morten Alhede ◽  
Peter Ø. Jensen ◽  
Claus Moser ◽  
Thomas Scheike ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Growth Rates ◽  
Polymorphonuclear Leukocytes ◽  
Growth Patterns ◽  
Tissue Samples ◽  
Content Type ◽  
Growth Physiology

ABSTRACTCystic fibrosis (CF) patients have increased susceptibility to chronic lung infections byPseudomonas aeruginosa, but the ecophysiology within the CF lung during infections is poorly understood. The aim of this study was to elucidate thein vivogrowth physiology ofP. aeruginosawithin lungs of chronically infected CF patients. A novel, quantitative peptide nucleic acid (PNA) fluorescencein situhybridization (PNA-FISH)-based method was used to estimate thein vivogrowth rates ofP. aeruginosadirectly in lung tissue samples from CF patients and the growth rates ofP. aeruginosain infected lungs in a mouse model. The growth rate ofP. aeruginosawithin CF lungs did not correlate with the dimensions of bacterial aggregates but showed an inverse correlation to the concentration of polymorphonuclear leukocytes (PMNs) surrounding the bacteria. A growth-limiting effect onP. aeruginosaby PMNs was also observedin vitro, where this limitation was alleviated in the presence of the alternative electron acceptor nitrate. The finding thatP. aeruginosagrowth patterns correlate with the number of surrounding PMNs points to a bacteriostatic effect by PMNs via their strong O2consumption, which slows the growth ofP. aeruginosain infected CF lungs. In support of this, the growth ofP. aeruginosawas significantly higher in the respiratory airways than in the conducting airways of mice. These results indicate a complex host-pathogen interaction in chronicP. aeruginosainfection of the CF lung whereby PMNs slow the growth of the bacteria and render them less susceptible to antibiotic treatment while enabling them to persist by anaerobic respiration.

RG2 glioma growth in rat cerebellum after subdural implantation

1986 ◽  
Vol 65 (2) ◽  
pp. 222-229 ◽  
Author(s):  
Stanislaw Krajewski ◽  
Jürgen C. W. Kiwit ◽  
Wolfgang Wechsler
Keyword(s):  
Light And Electron Microscopy ◽  
Tumor Model ◽  
Nerve Tissue ◽  
Blue Dye ◽  
Histological Techniques ◽  
Content Type ◽  
Rat Glioma ◽  
Glioma Growth ◽  
Microsurgical Techniques ◽  
Fine Print

✓ The nitrosourea-induced rat glioma clone RG2 was tested for its capacity to form multicellular tumor spheroids (MTS's). Resulting spheroids were investigated by light and electron microscopy with regard to their proliferation patterns and morphological features. Using microsurgical techniques and avoiding mechanical injury of the brain tissue, the authors successfully transplanted avascular MTS's under the dura of the cerebellum, above the vermis, in 43 adult syngeneic Fischer CD rats. The rate of tumor establishment was 93%, and the tumors that were solid and spheroid in shape grew exponentially. Neovascularization could be observed at 3 days after implantation, and invasion of the cerebellum occurred by 3 to 5 days. Neurological deterioration, including ataxia, impairment of walking, and apathy, could be observed after 10 days. The mean survival time was approximately 16 days. The subdural cerebellar tumors were studied by histological techniques, and two morphometric methods were applied to check the growth of implanted spheroids. All tumors were deeply stained with the Evans blue dye-albumin complex, demonstrating disturbance of the blood-brain barrier. The easy accessibility of the cerebellar vermis in rats, the microsurgical implantation of glioma spheroids under the dura avoiding nerve tissue disruption, and the high percentage of reproducible establishment of tumors favor this experimental brain-tumor model. This should be an excellent model for study of experimental therapies.

CSF leukotriene C4 following subarachnoid hemorrhage

1988 ◽  
Vol 69 (4) ◽  
pp. 488-493 ◽  
Author(s):  
Pietro Paoletti ◽  
Paolo Gaetani ◽  
Guido Grignani ◽  
Lucia Pacchiarini ◽  
Vittorio Silvani ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Subarachnoid Hemorrhage ◽  
Arterial Spasm ◽  
Lipoxygenase Pathway ◽  
Content Type ◽  
Symptomatic Vasospasm ◽  
Csf Levels ◽  
Fine Print

✓ Leukotrienes derive from arachidonic acid metabolism via the lipoxygenase pathway and modulate several cellular events. In the central nervous system, leukotrienes are mainly synthesized in the gray matter and in vascular tissues. Their production is enhanced in ischemic conditions and in experimental subarachnoid hemorrhage (SAH). Previous studies have indicated the ability of the leukotrienes C4 and D4 to constrict arterial vessels in vivo and in vitro and have suggested their involvement in the pathogenesis of cerebral arterial spasm. In the present study, the authors measured lumbar and cisternal cerebrospinal fluid (CSF) levels of leukotriene C4 in 48 patients who had suffered aneurysmal SAH. In 12 of the cases, symptomatic and radiological spasm was evident. The mean lumbar CSF level of immunoreactive-like activity of leukotriene C4 (i-LTC4) was significantly higher (p < 0.005) than in control cases, while the cisternal CSF level was higher than the lumbar mean concentration (p < 0.005). Patients presenting with vasospasm had significantly higher levels of i-LTC4 compared to patients without symptomatic vasospasm. This is the first report concerning monitoring of i-LTC4 levels in the CSF after SAH. The results of this study suggest that: 1) metabolism of arachidonic acid via the lipoxygenase pathway is enhanced after SAH; 2) the higher cisternal CSF levels of i-LTC4 may be part of the biological response in the perianeurysmal subarachnoid cisterns after the hemorrhage; and 3) the higher CSF levels of i-LTC4 in patients presenting with vasospasm suggest that a relationship exists between this compound and arterial spasm and/or reflect the development of cerebral ischemic damage.

Sign in / Sign up

Export Citation Format

Share Document