Yong-Hao Jin

The Effect of Hyaluronic Acid on the Invasiveness of Malignant Glioma Cells : Comparison of Invasion Potential at Hyaluronic Acid Hydrogel and Matrigel

OBJECTIVE Hyaluronidase (HAse), a degrading enzyme of hyaluronic acid (HA), is highly expressed in patients with malignant glioma. The purpose of this study was to verify whether HAse is related to the invasion of glioma cells. We also investigated if glioma cells with higher mobility in 2-dimensioal (2-D) method have also higher mobility at 3-dimensional (3-D) environment. METHODS Malignant glioma cell lines (U87MG, U251MG, U343MG-A, and U373MG) were used, and their HAse expressions were evaluated by HA zymography. The migration ability was evaluated by simple scratch technique. The invasiveness of each cell lines was evaluated by Matrigel invasion assay and HA hydrogel invasion assay. In HA hydrogel invasion assay, colonies larger than 150 microm were regarded as positive ones and counted. Statistical analysis of migration ability and invasion properties of each cell lines was performed using t-test. RESULTS In scratch test to examine migration ability of each cell lines, U87MG cells were most motile than others, and U343MG-A least motile. The HAse was expressed in U251MG and U343MG-A cell lines. However, U87MG and U373MG cell lines did not express HAse activity. In Matrigel invasion assay, the cell lines expressing HAse (U251MG and U343MG-A) were more invasive in the presence of HA than HAse deficient cell lines (U87MG and U373MG). In HA hydrogel invasion assay, the HAse-expressing cell lines formed colonies more invasively than HAse-deficient ones. CONCLUSION Malignant Glioma cells expressing HAse were more invasive than HAse-deficient ones in 3-dimensional environment. Therefore, it might be suggested that invasion of malignant gliomas is suppressed by inhibition of HAse expression or HA secretion. Additionally, the ability of 2-D migration and 3-D invasion might not be always coincident to each other in malignant glioma cells.

Anticancer activity of PEGylated matrix metalloproteinase cleavable peptide-conjugated adriamycin against malignant glioma cells.

Although matrix metalloproteinases (MMPs) play a crucial role in the invasion and growth of malignant gliomas, their increased activity in tumor environment can be used as a specific target for chemotherapy. We investigated whether polymer-drug conjugates formed via MMP-cleavable peptide linkages could provide MMP-responsive tumor targeting and cytotoxicity for malignant glioma cells. One end of an MMP-cleavable peptide was attached to the end of methoxy polyethylene glycol (MPEG) while the other end was attached to adriamycin (ADR). The release of drugs in the presence of conditioned media of U87MG cells was investigated. The cytotoxicities of the MMP-cleavable MPEG-peptide-ADR (PPA) conjugates and non-cleavable MPEG-ADR (PA) conjugates were investigated using U87MG cells. The (1)H nuclear magnetic resonance (NMR) spectra confirmed the conjugation of the two ends of the peptide to the ends of MPEG and ADR, respectively. Gelatin zymography showed that MMP-2 was strongly expressed in the media of U87MG cells. The PA conjugate did not release ADR either in the phosphate buffered saline (PBS) or conditioned media of U87MG cells. The PPA conjugate released ADR in the presence of the conditioned media of U87MG cells, but not in PBS only. In the cytotoxicity test using U87MG cells, ADR and PPA conjugate showed similar anti-proliferative activities, while the cytotoxicity of PA conjugate was lower than that of ADR. Considering that the cytotoxicity of the PPA conjugate was similar to that of ADR, MMP-cleavable polymer-drug conjugates can be used as targeting carriers for the purpose of inhibiting the proliferation of malignant glioma cells.

Screening for motility-associated genes in malignant astrocytoma cell lines

The most characteristic feature of a malignant astrocytoma is its early and extensive infiltration into adjacent parenchymal structures. We focused on detecting the possible expression changes as the determining factors for malignant astrocytoma’s motile ability. We confirmed that four of 39 genes showed different expression on DD-PCR by RT-PCR and Northern blot analysis. These findings suggest that the genes identified may be important for determining high motility in astrocytoma cell lines. These findings may help us understand the molecular invasion mechanism in astrocytomas.

GRIM-19 Expression and Function in Human Gliomas

OBJECTIVE We determined whether the expression of GRIM-19 is correlated with pathologic types and malignant grades in gliomas, and determined the function of GRIM-19 in human gliomas. METHODS Tumor tissues were isolated and frozen at -80 just after surgery. The tissues consisted of normal brain tissue (4), astrocytomas (2), anaplastic astrocytomas (2), oligodendrogliomas (13), anaplastic oligodendrogliomas (11), and glioblastomas (16). To profile tumor-related genes, we applied RNA differential display using a Genefishing DEG kit, and validated the tumor-related genes by reverse transcription polymerase chain reaction (RT-PCR). A human glioblastoma cell line (U343MG-A) was used for the GRIM-19 functional studies. The morphologic and cytoskeletal changes were examined via light and confocal microscopy. The migratory and invasive abilities were investigated by the simple scratch technique and Matrigel assay. The antiproliferative activity was determined by thiazolyl blue Tetrazolium bromide (MTT) assay and FACS analysis. RESULTS Based on RT-PCR analysis, the expression of GRIM-19 was higher in astrocytic tumors than oligodendroglial tumors. The expression of GRIM-19 was higher in high-grade tumors than low-grade tumors or normal brain tissue; glioblastomas showed the highest expression. After transfection of GRIM-19 into U343MG-A, the morphology of the sense-transfection cells became larger and more spindly. The antisense-transfection cells became smaller and rounder compared with wild type U343MG-A. The MTT assay showed that the sense-transfection cells were more sensitive to the combination of interferon-beta and retinoic acid than U343MG-A cells or antisense-transfection cells; the anti-proliferative activity was related to apoptosis. CONCLUSION GRIM-19 may be one of the gene profiles which regulate cell death via apoptosis in human gliomas.

Solitary intracranial subdural osteoma: Intraoperative findings and primary anastomosis of an involved cortical vein

We report a patient with a intracranial subdural osteoma with a large cortical vein passing through the subdural calcified mass. A 60-year-old man presented with an approximately 3-year history of persistent headache. Computerized tomography (CT) scanning showed a homogeneous high-density nodule attached to the inner surface of the right frontal skull. Intraoperatively, the hard mass was found to be located in the intradural subarachnoid space. A large cortical vein passed through the subdural mass and was anastomosed in an end-to-end fashion after the excision of the segment involved by the tumor. The histopathologic examination showed lamellated bony trabeculae lined by osteoblasts and the underlying dura was uninvolved by the tumor cells.