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Costello MA, Liu J, Kuehster L, Wang Y, Qin B, Xu X, Li Q, Smith WC, Lynd NA, Zhang F. Role of PLGA Variability in Controlled Drug Release from Dexamethasone Intravitreal Implants. Mol Pharm 2023; 20:6330-6344. [PMID: 37955890 DOI: 10.1021/acs.molpharmaceut.3c00742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2023]
Abstract
Long-acting injectable formulations based on poly(lactide-co-glycolide) (PLGA) have been commercialized for over 30 years in at least 20 FDA-approved products. These formulations offer several advantages, including reduced dosing frequency, improved patient compliance, and maintenance of therapeutic levels of drug. Despite extensive studies, the inherent complexity of the PLGA copolymer still poses significant challenges associated with the development of generic formulations having drug release profiles equivalent to those of the reference listed drugs. In addition, small changes to PLGA physicochemical properties or the drug product manufacturing process can have a major impact on the drug release profile of these long-acting formulations. This work seeks to better understand how variability in the physicochemical properties of similar PLGAs affects drug release from PLGA solid implants using Ozurdex (dexamethasone intravitreal implant) as the model system. Four 50:50, acid-terminated PLGAs of similar molecular weights were used to prepare four dexamethasone intravitreal implants structurally equivalent to Ozurdex. The PLGAs were extensively characterized by using a variety of analytical techniques prior to implant manufacture using a continuous, hot-melt extrusion process. In vitro release testing of the four structurally equivalent implants was performed in both normal saline and phosphate-buffered saline (PBS), yielding drastically different results between the two methods. In normal saline, no differences in the release profiles were observed. In PBS, the drug release profiles were sensitive to small changes in the residual monomer content, carboxylic acid end group content, and blockiness of the polymers. This finding further underscores the need for a physiologically relevant in vitro release testing method as part of a robust quality control strategy for PLGA-based solid implant formulations.
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Affiliation(s)
- Mark A Costello
- College of Pharmacy, Department of Molecular Pharmaceutics and Drug Delivery, University of Texas at Austin, Austin, Texas 78712, United States
| | - Joseph Liu
- College of Pharmacy, Department of Molecular Pharmaceutics and Drug Delivery, University of Texas at Austin, Austin, Texas 78712, United States
| | - Louise Kuehster
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, United States
| | - Yan Wang
- Center for Drug Evaluation and Research, Office of Generic Drugs, Office of Research and Standards, U.S. Food and Drug Administration, Silver Spring, Maryland 20993, United States
| | - Bin Qin
- Center for Drug Evaluation and Research, Office of Generic Drugs, Office of Research and Standards, U.S. Food and Drug Administration, Silver Spring, Maryland 20993, United States
| | - Xiaoming Xu
- Center for Drug Evaluation and Research, Office of Pharmaceutical Quality, Office of Testing and Research, U.S. Food and Drug Administration, Silver Spring, Maryland 20993, United States
| | - Qi Li
- Center for Drug Evaluation and Research, Office of Generic Drugs, Office of Research and Standards, U.S. Food and Drug Administration, Silver Spring, Maryland 20993, United States
| | - William C Smith
- Center for Drug Evaluation and Research, Office of Pharmaceutical Quality, Office of Testing and Research, U.S. Food and Drug Administration, Silver Spring, Maryland 20993, United States
| | - Nathaniel A Lynd
- McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, United States
- Texas Materials Institute, University of Texas at Austin, Austin, Texas 78712, United States
| | - Feng Zhang
- College of Pharmacy, Department of Molecular Pharmaceutics and Drug Delivery, University of Texas at Austin, Austin, Texas 78712, United States
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Costello MA, Liu J, Wang Y, Qin B, Xu X, Li Q, Smith WC, Lynd NA, Zhang F. Manufacturing dexamethasone intravitreal implants: Process control and critical quality attributes. Int J Pharm 2023; 647:123515. [PMID: 37844672 DOI: 10.1016/j.ijpharm.2023.123515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 09/20/2023] [Accepted: 10/13/2023] [Indexed: 10/18/2023]
Abstract
Over 20 long-acting injectable formulations based on poly(lactide-co-glycolide) (PLGA) have been approved by the FDA to date. PLGA is a biodegradable polymer that can extend drug release from these dosage forms for up to six months after administration. Despite the commercial success of several of these formulations, there are still a limited number of products that utilize PLGA, and there are currently no generic counterparts of these products on the market. Significant technical challenges are associated with preparation of chemically and structurally equivalent formulations that yield an equivalent drug release profile to the reference listed drug (RLD) both in vitro and in vivo. In this work, Ozurdex (dexamethasone intravitreal implant) was used as a model system to explore how the manufacturing process of PLGA-based solid implants impacts the quality and performance of the dosage form. Control of implant structural characteristics, including diameter, internal porosity, and surface roughness, was required to maintain accurate unit dose potency. Implants were prepared by a continuous hot-melt extrusion process that was thoroughly characterized to show the importance of precise feeding control to meet dimensional specifications. Five extruder die designs were evaluated using the same hot-melt extrusion process to produce five structurally-distinct implants. The structural differences did not alter the in vitro drug release profile when tested in both normal saline and phosphate-buffered saline (pH 7.4); however, implant porosity was shown to impact the mechanical strength of the implants. This work seeks to provide insight into the manufacturing process of PLGA-based solid implants to support development of future novel and generic drug products.
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Affiliation(s)
- Mark A Costello
- University of Texas at Austin, College of Pharmacy, Department of Molecular Pharmaceutics and Drug Delivery, Austin, TX, USA
| | - Joseph Liu
- University of Texas at Austin, College of Pharmacy, Department of Molecular Pharmaceutics and Drug Delivery, Austin, TX, USA
| | - Yan Wang
- U.S. Food and Drug Administration, Center for Drug Evaluation and Research, Office of Generic Drugs, Office of Research and Standards, Silver Spring, MD, USA
| | - Bin Qin
- U.S. Food and Drug Administration, Center for Drug Evaluation and Research, Office of Generic Drugs, Office of Research and Standards, Silver Spring, MD, USA
| | - Xiaoming Xu
- U.S. Food and Drug Administration, Center for Drug Evaluation and Research, Office of Pharmaceutical Quality, Office of Testing and Research, Silver Spring, MD, USA
| | - Qi Li
- U.S. Food and Drug Administration, Center for Drug Evaluation and Research, Office of Generic Drugs, Office of Research and Standards, Silver Spring, MD, USA
| | - William C Smith
- U.S. Food and Drug Administration, Center for Drug Evaluation and Research, Office of Pharmaceutical Quality, Office of Testing and Research, Silver Spring, MD, USA
| | - Nathaniel A Lynd
- University of Texas at Austin, McKetta Department of Chemical Engineering and Texas Materials Institute, Austin, TX, USA
| | - Feng Zhang
- University of Texas at Austin, College of Pharmacy, Department of Molecular Pharmaceutics and Drug Delivery, Austin, TX, USA.
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Costello MA, Liu J, Chen B, Wang Y, Qin B, Xu X, Li Q, Lynd NA, Zhang F. Drug release mechanisms of high-drug-load, melt-extruded dexamethasone intravitreal implants. Eur J Pharm Biopharm 2023; 187:46-56. [PMID: 37037387 DOI: 10.1016/j.ejpb.2023.04.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 03/27/2023] [Accepted: 04/04/2023] [Indexed: 04/12/2023]
Abstract
Ozurdex is an FDA-approved sustained-release, biodegradable implant formulated to deliver the corticosteroid dexamethasone to the posterior segment of the eye for up to 6 months. Hot-melt extrusion is used to prepare the 0.46 mm × 6 mm, rod-shaped implant by embedding the drug in a matrix of poly(lactic-co-glycolic acid) (PLGA) in a 60:40 drug:polymer ratio by weight. In our previous work, the Ozurdex implant was carefully studied and reverse engineered to produce a compositionally and structurally equivalent implant for further analysis. In this work, the reverse-engineered implant is thoroughly characterized throughout the in vitro dissolution process to elucidate the mechanisms of controlled drug release. The implant exhibits a triphasic release profile in 37 °C normal saline with a small burst release (1-2 %), a one-week lag phase with limited release (less than10 %), and a final phase where the remainder of the dose is released over 3-4 weeks. The limited intermolecular interaction between dexamethasone and PLGA renders the breakdown of the polymer the dominating mechanism of controlled release. A close relationship between drug release and total implant mass loss was observed. Unique chemical and structural differences were seen between the core of the implant and the implant surface driven by diffusional limitations, autocatalytic hydrolysis, and osmotic effects.
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Affiliation(s)
- Mark A Costello
- University of Texas at Austin, College of Pharmacy, Department of Molecular Pharmaceutics and Drug Delivery, Austin, TX, USA
| | - Joseph Liu
- University of Texas at Austin, College of Pharmacy, Department of Molecular Pharmaceutics and Drug Delivery, Austin, TX, USA
| | - Beibei Chen
- University of Texas at Austin, College of Pharmacy, Department of Molecular Pharmaceutics and Drug Delivery, Austin, TX, USA
| | - Yan Wang
- U.S. Food and Drug Administration, Center for Drug Evaluation and Research, Office of Generic Drugs, Office of Research and Standards, Silver Spring, MD, USA
| | - Bin Qin
- U.S. Food and Drug Administration, Center for Drug Evaluation and Research, Office of Generic Drugs, Office of Research and Standards, Silver Spring, MD, USA
| | - Xiaoming Xu
- U.S. Food and Drug Administration, Center for Drug Evaluation and Research, Office of Pharmaceutical Quality, Office of Testing and Research, Silver Spring, MD, USA
| | - Qi Li
- U.S. Food and Drug Administration, Center for Drug Evaluation and Research, Office of Generic Drugs, Office of Research and Standards, Silver Spring, MD, USA
| | - Nathaniel A Lynd
- University of Texas at Austin, McKetta Department of Chemical Engineering and Texas Materials Institute, Austin, TX, USA
| | - Feng Zhang
- University of Texas at Austin, College of Pharmacy, Department of Molecular Pharmaceutics and Drug Delivery, Austin, TX, USA.
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Costello MA, Liu J, Wang Y, Qin B, Xu X, Li Q, Lynd NA, Zhang F. Reverse engineering the Ozurdex dexamethasone intravitreal implant. Int J Pharm 2023; 634:122625. [PMID: 36690129 DOI: 10.1016/j.ijpharm.2023.122625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 01/09/2023] [Accepted: 01/16/2023] [Indexed: 01/21/2023]
Abstract
Ozurdex is a biodegradable implant formulated for sustained-release delivery of the corticosteroid dexamethasone to the posterior segment of the eye. The small, rod-shaped implant is administered directly to the vitreous using a dedicated applicator, and releases drug for up to 6 months after administration. Sustained release is achieved by embedding dexamethasone in a matrix of 50:50 poly(lactic-co-glycolic acid) (PLGA). In this work, the Ozurdex implant was thoroughly characterized to enable the reverse engineering of a compositionally and structurally equivalent implant. Advanced imaging techniques such as scanning electron microscopy (SEM) and microcomputed tomography (microCT) revealed that the Ozurdex implant exhibits an irregular surface and an internal porosity of 6% due to a large number of discrete voids approximately 3 μm in diameter. Thermal and spectroscopic analyses showed limited interaction between the drug and the polymer, resulting in a two-phase system of dexamethasone crystals embedded within a PLGA matrix. Reverse-engineered implants with properties similar to Ozurdex were prepared using a two-step hot-melt extrusion process. The reverse-engineered implants exhibited a triphasic drug release profile similar to Ozurdex. This work seeks to provide insight into the manufacturing process and characterization of PLGA-based solid implants to support future generic product development.
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Affiliation(s)
- Mark A Costello
- University of Texas at Austin, College of Pharmacy, Department of Molecular Pharmaceutics and Drug Delivery, Austin, TX, USA
| | - Joseph Liu
- University of Texas at Austin, College of Pharmacy, Department of Molecular Pharmaceutics and Drug Delivery, Austin, TX, USA
| | - Yan Wang
- U.S. Food and Drug Administration, Center for Drug Evaluation and Research, Office of Generic Drugs, Office of Research and Standards, Silver Spring, MD, USA
| | - Bin Qin
- U.S. Food and Drug Administration, Center for Drug Evaluation and Research, Office of Generic Drugs, Office of Research and Standards, Silver Spring, MD, USA
| | - Xiaoming Xu
- U.S. Food and Drug Administration, Center for Drug Evaluation and Research, Office of Pharmaceutical Quality, Office of Testing and Research, Silver Spring, MD, USA
| | - Qi Li
- U.S. Food and Drug Administration, Center for Drug Evaluation and Research, Office of Generic Drugs, Office of Research and Standards, Silver Spring, MD, USA
| | - Nathaniel A Lynd
- University of Texas at Austin, McKetta Department of Chemical Engineering and Texas Materials Institute, Austin, TX, USA
| | - Feng Zhang
- University of Texas at Austin, College of Pharmacy, Department of Molecular Pharmaceutics and Drug Delivery, Austin, TX, USA.
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Tsai MC, Candy G, Costello MA, Grieve AD, Brand M. Do iatrogenic serosal injuries result in small bowel perforation in a rabbit model? S AFR J SURG 2017; 55:18-22. [PMID: 28876619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
BACKGROUND Surgical dogma dictates that serosal injuries should be repaired during laparotomy as these injuries may result in localised areas of bowel ischaemia and may perforate. No study has investigated whether there is a correlation between the extent of serosal injuries and the risk for perforation under normal physiological conditions. We hypothesized that small bowel serosal injuries do not result in early or late perforation at physiological intraluminal pressures regardless of their size. METHOD An in-vivo rabbit small bowel serosal injury model was developed and two experiments were conducted. The first - to determine whether and at which pressures various lengths and circumferences of serosal injuries in small bowel result in immediate bowel perforation - was performed infusing saline into isolated bowel segments with or without a variety of serosal injuries. In the second study - to determine whether or not serosal injuries result in delayed perforation - a range of injuries was created in rabbits and the effect assessed at re-laparotomy 5 days after the creation of the injury. RESULTS No perforations were observed at the site of serosal injuries at physiological intraluminal pressures. Perforations occurred at 43.7+ 18.6 cmH₂O, 23.3+ 14.4 cmH₂O, and 24.4+ 23.9 cmH₂O for controls, 4 cm long and 100% circumference serosal injuries respectively (p-value = 0.18 for various lengths and 0.71 for various circumferences). No serosal injuries perforated within 72 or 120 hours after creation. CONCLUSION Small bowel serosal injuries do not perforate or leak at physiological intraluminal pressures, either at the time of creation or up to 120 hours thereafter.
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Affiliation(s)
- M C Tsai
- Department of Surgery, University of the Witwatersrand. 9th Floor, Faculty of Health Sciences
| | - G Candy
- Department of Surgery, University of the Witwatersrand. 9th Floor, Faculty of Health Sciences
| | - M A Costello
- Central Animal Services Unit, University of the Witwatersrand. 1st Floor, Faculty of Health Sciences
| | - A D Grieve
- Department of Surgery, University of the Witwatersrand. 9th Floor, Faculty of Health Sciences
| | - M Brand
- Department of Surgery, University of the Witwatersrand. 9th Floor, Faculty of Health Sciences
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Abstract
Uterine torsion is a twisting of the uterus or uterine horn perpendicular to its long axis. We report a case of uterine torsion in an adult breeding Sprague Dawley rat. The rat died a month after her last recorded delivery. Post mortem examination of the rat revealed 270 degrees torsion of the right uterine horn. The uterus contained a single foetus. The liver was pale and enlarged. The rest of the viscera appeared normal. Histopathological examination showed acute hepatic necrosis and pulmonary congestion with mild lymphocytic infiltrates peribronchially. The acute hepatic necrosis may have been associated with septicaemia due to compromised blood vessels following the uterine torsion. The presence of a single foetus could have resulted in foeto-maternal disproportion with resultant uterine torsion. Torsion of the uterus can be accompanied by haemostatic and metabolic complications, which could have caused the death of the rat. Although uterine torsion is a rare condition in rats, it should be considered as a potential complication of gestation in animal breeding units.
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Affiliation(s)
- K H Erlwanger
- School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, 7 York Rd, Parktown 2193, South Africa.
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Zhu TS, Costello MA, Talsma CE, Flack CG, Crowley JG, Hamm LL, He X, Hervey-Jumper SL, Heth JA, Muraszko KM, DiMeco F, Vescovi AL, Fan X. Endothelial cells create a stem cell niche in glioblastoma by providing NOTCH ligands that nurture self-renewal of cancer stem-like cells. Cancer Res 2011; 71:6061-72. [PMID: 21788346 DOI: 10.1158/0008-5472.can-10-4269] [Citation(s) in RCA: 282] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
One important function of endothelial cells in glioblastoma multiforme (GBM) is to create a niche that helps promote self-renewal of cancer stem-like cells (CSLC). However, the underlying molecular mechanism for this endothelial function is not known. Since activation of NOTCH signaling has been found to be required for propagation of GBM CSLCs, we hypothesized that the GBM endothelium may provide the source of NOTCH ligands. Here, we report a corroboration of this concept with a demonstration that NOTCH ligands are expressed in endothelial cells adjacent to NESTIN and NOTCH receptor-positive cancer cells in primary GBMs. Coculturing human brain microvascular endothelial cells (hBMEC) or NOTCH ligand with GBM neurospheres promoted GBM cell growth and increased CSLC self-renewal. Notably, RNAi-mediated knockdown of NOTCH ligands in hBMECs abrogated their ability to induce CSLC self-renewal and GBM tumor growth, both in vitro and in vivo. Thus, our findings establish that NOTCH activation in GBM CSLCs is driven by juxtacrine signaling between tumor cells and their surrounding endothelial cells in the tumor microenvironment, suggesting that targeting both CSLCs and their niche may provide a novel strategy to deplete CSLCs and improve GBM treatment.
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Affiliation(s)
- Thant S Zhu
- Department of Neurosurgery, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA
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8
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Zhu TS, Costello MA, Hervey-Jumper S, DiMeco F, Vescovi AL, Heth JA, Muraszko KM, Fan X. Abstract 3297: Endothelial cells function as a niche to cancer stem-like cells by providing notch ligands in glioblastoma. Cancer Res 2011. [DOI: 10.1158/1538-7445.am2011-3297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Recent data show that endothelial cells function as a stem cell niche to promote CD133-positive cancer stem-like cells (CSLCs) self-renewal in glioblastoma (GBM). However, the molecular mechanism by which endothelial cells function as a stem cell niche is largely unknown. We had demonstrated recently that activation of NOTCH signaling is required for GBM CSLC propagation both in vitro and in vivo. To investigate if the acquisition of NOTCH activation in GBM CSLCs results from adjacent endothelial cells, we first examined the expression of NOTCH ligands JAG/DLL in primary GBM frozen samples. We found that JAG1, JAG2 and DLL4 are expressed mostly in endothelial cells adjacent to NESTIN- and NOTCH receptor-positive cancer cells. Some tumor cells also express JAG1, JAG2, and DLL1, but not DLL4, adjacent to NESTIN- and NOTCH-receptor positive cells in primary GBMs. Furthermore, we found that forced differentiated GBM cells from GBM neurospheres express a higher level of NOTCH ligands and a lower level of stem cell marker CD133, have reduced NOTCH activity, and are less tumorigenic in mice compared to GBM neurospheres. In addition, when we co-cultured GBM neurospheres with human brain microvascular endothelial cells (hBMECs) which express NOTCH ligands JAG/DLL, we found that hBMECs promote GBM neurosphere growth, increase the CD133-positive CSLC population and clonogenicity in vitro, whereas knocking down JAG1 or DLL4 in hBMECs abrogates hBMEC-induced GBM growth both in vitro and in vivo. Finally, we found that knockdown of JAG1 or DLL4 in hBMECs decreases growth of GBM intracranial xenograft in mice through reducing the CD133-positive population. In summary, we have demonstrated that NOTCH activation in GBM CSLCs is driven by juxtacrine signaling between tumor cells and surrounding endothelial cells, suggesting that targeting both CSLCs and their niche may provide an effective strategy to deplete GBM CSLCs.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3297. doi:10.1158/1538-7445.AM2011-3297
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Affiliation(s)
| | | | | | | | | | | | | | - Xing Fan
- 1Univ. of Michigan, Ann Arbor, MI
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He J, Liu Y, Zhu TS, Xie X, Costello MA, Talsma CE, Flack CG, Crowley JG, Dimeco F, Vescovi AL, Fan X, Lubman DM. Glycoproteomic analysis of glioblastoma stem cell differentiation. J Proteome Res 2010; 10:330-8. [PMID: 21110520 DOI: 10.1021/pr101158p] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cancer stem cells are responsible for tumor formation through self-renewal and differentiation into multiple cell types and thus represent a new therapeutic target for tumors. Glycoproteins play a critical role in determining the fates of stem cells such as self-renewal, proliferation, and differentiation. Here we applied a multilectin affinity chromatography and quantitative glycoproteomics approach to analyze alterations of glycoproteins relevant to the differentiation of a glioblastoma-derived stem cell line HSR-GBM1. Three lectins including concanavalin A (Con A), wheat germ agglutinin (WGA), and peanut agglutinin (PNA) were used to capture glycoproteins, followed by LC-MS/MS analysis. A total of 73 and 79 high-confidence (FDR < 0.01) glycoproteins were identified from the undifferentiated and differentiated cells, respectively. Label-free quantitation resulted in the discovery of 18 differentially expressed glycoproteins, wherein 9 proteins are localized in the lysosome. All of these lysosomal glycoproteins were up-regulated after differentiation, where their principal function was hydrolysis of glycosyl residues. Protein-protein interaction and functional analyses revealed the active involvement of lysosomes during the process of glioblastoma stem cell differentiation. This work provides glycoprotein markers to characterize differentiation status of glioblastoma stem cells that may be useful in stem-cell therapy of glioblastoma.
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Affiliation(s)
- Jintang He
- Department of Surgery, University of Michigan Medical Center, Ann Arbor, Michigan 48109, USA
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Enguita-Germán M, Gurrea M, Schiapparelli P, Zhu TS, Crowley JG, Hamm LL, Costello MA, He X, Talsma CE, Flack CG, Hervey-Jumper SL, Heth JA, Muraszko KM, Rey JA, Fan X, Castresana JS. KIT expression and methylation in medulloblastoma and PNET cell lines and tumors. J Neurooncol 2010; 103:247-53. [PMID: 20853134 DOI: 10.1007/s11060-010-0391-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2010] [Accepted: 08/26/2010] [Indexed: 02/02/2023]
Abstract
The stem cell factor/kit tyrosine kinase receptor pathway is related to tumor growth and progression in several cancers including Ewing sarcoma, a peripheral PNET (pPNET). Identifying additional groups of tumors that may use the pathway is important as they might be responsive to imatinib mesylate treatment. MB and central PNET (cPNET) are embryonal tumors of the CNS that share similar undifferentiated morphology with Ewing sarcomas and display aggressive clinical behavior. cPNET outcome is significantly lower than MB outcome, even for localized tumors treated with high-risk MB therapy. The elucidation of signaling pathways involved in MB and cPNET pathogenesis, and the discovery of new therapeutic targets is necessary to improve the treatment of these neoplasms. We analyzed KIT expression in 2 MB, one pPNET, one cPNET and 2 rhabdomyosarcoma (RMS) cell lines. Also, in 13 tumor samples (12 MB and one cPNET), we found KIT overexpression in the most aggressive cell lines (metastatic MB and pPNET). Hypermethylation of KIT was clear in the RMS non-expressing cell lines. Among MB tumors, we could see variable levels of KIT expression; a subset of them (25%) might be related in its growth pattern to KIT up-regulation. No methylated KIT was detected in the tumors expressing the lowest levels of KIT. Our results point to methylation as an epigenetic regulatory mechanism for KIT inhibition only in the KIT non-expressing RMS cell lines, and neither in the rest of the cell lines nor in the tumor samples.
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Affiliation(s)
- Mónica Enguita-Germán
- Brain Tumor Biology Unit-CIFA, University of Navarra School of Sciences, Irunlarrea 1, 31008, Pamplona, Spain
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11
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Costello MA. Survey finds health care workers short on commitment to employers. Continuum Soc Soc Work Leadersh Health Care 2000; 20:23. [PMID: 11199383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
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12
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Costello MA, Lleno LC, Jensen ER. Determinants of two major early-childhood diseases and their treatment in the Philippines: findings from the 1993 National Demographic Survey. Asia Pac Popul Res Abstr 1996:1-2. [PMID: 12291537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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13
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Garg VK, Costello MA, Czuba BA. Purification and production of therapeutic grade proteins. Bioprocess Technol 1991; 12:29-54. [PMID: 1367502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/25/2023]
Affiliation(s)
- V K Garg
- Bio-Response, Inc., Hayward, California
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14
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Chapman AB, Costello MA, Lee F, Ringold GM. Amplification and hormone-regulated expression of a mouse mammary tumor virus-Eco gpt fusion plasmid in mouse 3T6 cells. Mol Cell Biol 1983; 3:1421-9. [PMID: 6312292 PMCID: PMC369988 DOI: 10.1128/mcb.3.8.1421-1429.1983] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Mouse 3T6 cells were transformed with a chimeric DNA plasmid, pSVMgpt, in which the mouse mammary tumor virus (MMTV) promoter was fused to the Escherichia coli gene encoding xanthine-guanine phosphoribosyl transferase (Eco gpt). The transformants exhibited glucocorticoid-inducible expression of Eco gpt. With limiting xanthine concentrations, conditions were established in which cell growth became hormone dependent. Cells selected for their ability to grow in limiting concentrations of both xanthine and glucocorticoids contained amplified levels of Eco gpt DNA, and expression of Eco gpt remained glucocorticoid inducible in these amplified cells. Thus, amplification of the MMTV promoter region in itself did not abolish hormonal responsiveness of a gene. In addition to increased levels of Eco gpt DNA, some of the selected cells also exhibited increased levels (two- to threefold) of glucocorticoid receptors. Lastly, we found that excessive expression of Eco gpt is toxic to 3T6 cells; by maintaining low hormone levels and, therefore, low levels of expression, we were able to select cells with amplified Eco gpt. Thus, the MMTV promoter may be of general utility in expressing genes whose products may be lethal if they are produced in excessive quantities.
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15
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Costello MA. Chinese-Filipino fertility differences in Cagayan de Oro: some findings from a medium-sized Philippine city. J Southeast Asian Stud 1981; 12:452-463. [PMID: 12312311 DOI: 10.1017/s0022463400009978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
While increasing sociological and anthropological attention has been directed towards the position of the Chinese in the Philippines, such research has often lacked a quantitative orientation. Perhaps owing to the intense concern centring on the political question of citizenship rights, there have as yet been a few empirical analyses of the attitudes and behaviour of persons of Chinese descent in the Philippines. Even studies designed to investigate Chinese “assimilation” to Philippine culture have been characterized more by a concern with political and legal questions than by an interest in social theory or research methodologies.
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Costello MA. Education and fertility in the Philippines: an exercise in the sociology of demographic knowledge. Philipp Sociol Rev 1979; 27:63-72. [PMID: 12311043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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Costello MA. A reply to Dr. Concepcion's [rejoinder to Education and fertility in the Philippines]. Philipp Sociol Rev 1979; 27:73-5. [PMID: 12311045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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Costello MA. Valium induction. J Am Assoc Nurse Anesth 1971; 39:185-90. [PMID: 5207582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Costello MA, Peters PA. The ion potassium. J Am Assoc Nurse Anesth 1970; 38:126-33. [PMID: 5199195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Kalina JA, Costello MA. Nursing care aided through closed circuit TV. Nurs Outlook 1966; 14:39-42. [PMID: 5178579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Reece E, McFadden P, Costello MA. Significance of arcus senilis under anesthesia. J Am Assoc Nurse Anesth 1966; 34:169-73. [PMID: 5177119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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