SEARCH · PubMed Health

Results for “IOMM-Lee”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

13 recordsLinked to original sources

PubMed1990

Characterization of a newly established malignant meningioma cell line of the human brain: IOMM-Lee.

A permanent malignant meningioma (MM) cell line of the human brain designated "IOMM-Lee" is reported. This cell line was successfully established from the tumor of a 61-year-old Chinese man with repeated recurrent primary intraosseous malignant meningioma of the skull. It has been subcultured for more than 60 passages during the past 30 months. The doubling time of cultured cells is approximately 62 hours. Tumorigenicity in athymic nude mice (Balb/c-nu/nu) who develop multiple pulmonary metastases was observed; the doubling time of tumor volume in vivo is approximately 5 days. Karyotypic analysis revealed this cell line to be of human origin and near-diploid, with a modal chromosome number of 49. The mesenchymal tumor marker vimentin and intracytoplasmic microfilaments were identified in the cytoplasm of tumor cells by indirect immunohistochemical peroxidase-anti-peroxidase assays and immunogold ultrastructural localization by transmission electron microscopy, respectively. Scanning electron microscopy of cultured cells and xenografted tumors revealed ellipsoidal or carrot-shaped tumor cells presenting a wrinkled surface with short sparse microvilli. Potential proliferating activity was determined by Ki-67 monoclonal antibody; the Ki-67 labeling index of cultured cells and xenografted tumors was approximately 36% and 30%, respectively. This newly established malignant meningioma cell line of the human brain may prove useful as a research model.

Animals↗

PubMed2007

Celecoxib inhibits meningioma tumor growth in a mouse xenograft model.

BACKGROUND: Treatments for recurrent meningiomas are limited. We previously demonstrated universal expression of COX-2 in meningiomas and dose-dependent growth inhibition in vitro with celecoxib, a COX-2 inhibitor. We therefore tested the effects of celecoxib on meningioma growth in a mouse xenograft model. METHODS: Meningioma cell lines (IOMM-Lee, CH157-MN, WHO grade I primary cultured tumor) were transplanted into flanks of nude mice fed mouse chow with celecoxib at varying concentrations (0, 500, 1000, 1500 ppm) ad libitum. Tumors were measured biweekly and processed for MIB-1, Factor VIII, COX-2, and VEGF, and assayed with transferase-mediated dUTP-biotin nick-end labeling (TUNEL). RESULTS: Celecoxib reduced growth of mean tumor volume by 66% (P < .05), 25% (P > .05), and 65% (P < .05) compared with untreated controls in IOMM-Lee, CH157-MN, and benign tumors, respectively. IOMM-Lee tumors removed from celecoxib treatment regained a growth rate similar to the control. Blood vessel density decreased and apoptotic cells increased in treated flank tumors. Diminished COX-2 expression and VEGF were observed in treated IOMM-Lee tumors. Mean plasma celecoxib levels were 845, 1540, and 2869 ng/mL, for low-, medium-, and high-dose celecoxib, respectively. CONCLUSIONS: Celecoxib inhibits meningioma growth in vivo at plasma levels achievable in humans. Celecoxib-treated tumors were less vascular with increased apoptosis. IOMM-Lee tumors treated with celecoxib showed decreased COX-2 and VEGF expression. COX-2 inhibitors may have a role in the treatment of recurrent meningiomas.

Animals↗

PubMed2003

Identification of a third Protein 4.1 tumor suppressor, Protein 4.1R, in meningioma pathogenesis.

Meningiomas are common central nervous system tumors; however, the mechanisms underlying their pathogenesis are largely undefined. In this report, we demonstrate that a third Protein 4.1 family member, Protein 4.1R, functions as a meningioma tumor suppressor. We observed loss of Protein 4.1R expression in two meningioma cell lines (IOMM-Lee, CH157-MN) by Western blotting as well as in 6 of 15 sporadic meningiomas by immunohistochemistry and fluorescence in situ hybridization. In support of a meningioma tumor suppressor function, Protein 4.1R overexpression resulted in reduced IOMM-Lee and CH157-MN cell proliferation. Similar to the Protein 4.1B and merlin tumor suppressors, Protein 4.1R membrane localization increased significantly under conditions of growth arrest in vitro. Lastly, we show that Protein 4.1R interacted with a subset of merlin/Protein 4.1B interactors including CD44 and betaII-spectrin. Collectively, these results suggest that Protein 4.1R functions as an important tumor suppressor in the molecular pathogenesis of meningioma.

Animals↗

PubMed2004

Disruption of 14-3-3 binding does not impair Protein 4.1B growth suppression.

Meningiomas are common central nervous system tumors; however, the mechanisms underlying their pathogenesis are largely unknown. Collaborative studies from our laboratory demonstrated a direct association of 14-3-3 with the meningioma tumor suppressor Protein 4.1B, which was not observed with other members of the Protein 4.1 family, including the NF2 meningioma tumor suppressor, merlin/schwannomin. Given the role of 14-3-3 in the regulation of cell proliferation and apoptosis, we sought to determine the functional significance of 14-3-3 binding to Protein 4.1B growth suppression. Based on comparative binding studies performed with additional members of the Protein 4.1 family, we generated specific missense mutations within the minimal growth suppressor fragment of Protein 4.1B (DAL-1, differentially expressed in adenocarcinoma of the lung). Complementary in vitro GST affinity chromatography and in vivo interaction experiments demonstrated that the F359Y mutation abrogated binding to 14-3-3, but did not impair DAL-1 binding to other known Protein 4.1B interacting proteins. Similar to wild-type DAL-1, the expression of the F359Y DAL-1 14-3-3-binding mutant resulted in reduced Protein 4.1B-deficient IOMM-Lee and CH157-MN meningioma cell line colony formation. Moreover, similar to wild-type DAL-1, the stable expression of the DAL-1 F359Y mutant significantly reduced cell proliferation in independently isolated IOMM-Lee clones, as assessed by thymidine incorporation. Collectively, these results suggest that binding to 14-3-3 is not essential for the growth suppressor function of Protein 4.1B in meningiomas.

14-3-3 Proteins↗

PubMed2025

Novel insights into hypoxia-driven transcriptomic and epigenetic landscapes in grade 3 meningioma.

BACKGROUND: Meningiomas are among the most prevalent central nervous system (CNS) tumors, with up to 20% of cases exhibiting recurrence or aggressive behavior. Hypoxia is a key driver of malignant transformation and therapeutic resistance, yet its molecular basis in meningioma remains poorly understood. METHODS: We conducted integrative transcriptomic and epigenomic profiling of IOMM-Lee cells (grade 3 meningioma) cultured under hypoxic (0.2% O₂) and normoxic conditions. RNA-sequencing and Illumina MethylationEPIC v2.0 data were analyzed in R using DESeq2 and minfi, respectively. Functional enrichment, transcription-factor binding analysis, and pathway mapping (clusterProfiler, enrichR) were performed. Findings were cross-validated in public meningioma datasets, in Indian meningioma patient cohort and cell line via RT-qPCR, and azacytidine-based demethylation assay. Functional role of the candidate gene was elucidated in vitro via cellular assays. RESULTS: Hypoxia triggered a canonical HIF1A-driven transcriptional program activating glycolytic and angiogenic pathways while downregulating genes associated with DNA repair and replication in meningioma. Several differentially expressed genes (DEGs) were identified as known oncogenes, tumor-suppressors, or associated with immune regulation and stemness. Promoter motif analysis identified HIF1, SP1, TP53, BRCA1, and E2F1 as enriched transcriptional regulators. We validated hypoxia and HIF1-mediated regulation of some of the top DEGs. DNA-methylation analysis revealed epigenetic silencing of RTN4IP1 and ZBTB7C under hypoxia, reversible upon azacytidine treatment. Integrative comparison with patient datasets highlighted SLITRK2, PDE4C, SGCD, and LRP1B as hypoxia-responsive genes associated with poor prognosis. Several hypoxia-regulated genes also showed significant correlation with known hypoxia biomarkers, VEGFA and CA9. IGFBP3 and NDRG1 were among the top hypoxia-associated upregulated genes, and IGFBP3 expression was linked to advanced meningioma grades. Knockdown of IGFBP3 via siRNA in hypoxia-treated IOMM-Lee cells was associated with reduced cell proliferation and migration. CONCLUSIONS: This study presents the first integrated transcriptomic–epigenomic landscape of hypoxia in grade 3 meningioma, uncovering regulatory networks and candidate biomarkers with prognostic and therapeutic potential. These findings provide a foundation for future translational studies targeting hypoxia-driven tumor progression in meningioma.

Humans↗

PubMed2006

Calcium channel antagonists augment hydroxyurea- and ru486-induced inhibition of meningioma growth in vivo and in vitro.

OBJECTIVE: Although the chemotherapy drug hydroxyurea (HU) and the antiprogesterone mifepristone (RU486) have been used to treat meningiomas for which surgical and radiation therapies have failed, results have been disappointing. The addition of calcium channel antagonists (CCAs) to chemotherapeutic drugs enhances tumor growth inhibition in other tumor types, and the authors demonstrated that CCAs can block meningioma growth in vitro and in vivo. The purpose of this study was to test the effects of the addition of a CCA to HU or RU486 on meningioma growth. METHODS: Primary and malignant (IOMM-Lee) meningioma cell lines were treated with HU, RU486, or either of these plus diltiazem or verapamil. Assays for cell growth, apoptosis, and fluorescent-activated cell sorting were performed on in vitro cultures. Similar cell lines were implanted into nude mice and were treated with HU or RU486, in combination with a CCA. Tumors were analyzed by light microscopy, MIB-1, and factor VIII immunohistochemical staining studies. RESULTS: The addition of diltiazem or verapamil to HU or RU486 augmented meningioma growth inhibition by 20 to 60% in vitro. In vivo, tumors treated with combination drugs were smaller; and immunohistochemical analysis of the IOMM-Lee tumors showed a 10% decrease in the MIB-1 ratio (from 0.41 to 0.30) and an approximate 75% decrease in microvascular density. CONCLUSION: The addition of diltiazem or verapamil to HU or RU486 augments meningioma growth inhibition in vitro by inducing apoptosis and G1 cell-cycle arrest. The combination of HU and diltiazem inhibited the growth of meningiomas in vivo by decreasing proliferation and microvascular density. These results suggest a possible role for these drugs as an additional adjuvant therapy for recurrent or unresectable meningiomas.

Aged↗

PubMed2004

Functional significance of S6K overexpression in meningioma progression.

One common genetic change in anaplastic meningiomas is amplification of chromosome 17q23 containing the S6 kinase (S6K) gene. We show, for the first time to our knowledge, increased S6K mRNA expression in anaplastic meningiomas compared with benign tumors. To evaluate S6K as a candidate meningioma progression gene, we generated IOMM-Lee human meningioma cell lines overexpressing S6K. Whereas no effect of S6K overexpression on meningioma cell growth, motility, or adhesion was observed in vitro, S6K overexpression resulted in increased tumor size in vivo. Collectively, these results suggest that S6K is functionally important for meningioma progression and may represent a target for future meningioma therapy.

Animals↗

PubMed2005

Aberrant CpG island hypermethylation profile is associated with atypical and anaplastic meningiomas.

Hypermethylation of promoter CpG islands is a common epigenetic event in a variety of human cancers. The aim of this study was to investigate whether promoter hypermethylation of cancer-related genes is involved in the development and progression of meningiomas. The methylation status at the promoter region of 10 cancer-related genes was examined by methylation-specific polymerase chain reaction in a cohort of 48 meningiomas including 16 benign, 19 atypical, and 13 anaplastic variants. The relationship of promoter hypermethylation and transcriptional silencing was determined by treatment of cells with demethylating agent 5-aza-2'-deoxycytidine followed by reverse transcription-polymerase chain reaction. Our results showed that 50% (24/48) of meningiomas exhibited promoter hypermethylation in at least one of the genes but not in normal leptomeninges, indicating that aberrant hypermethylation is tumor-specific. Promoter hypermethylation was detected in glutathione S -transferases P1 at 27%, thrombospondin-1 at 15%, retinoblastoma 1 at 10%, cyclin-dependent kinase inhibitor 2A at 10%, O 6 -methylguanine-DNA methyltransferase at 6%, and death-associated protein kinase 1, von Hippel-Lindau, p14 ARF , and cyclin-dependent kinase inhibitor 2B, each at 4%. No promoter hypermethylation was detected in the tissue inhibitor of metalloproteinase 3 gene. Treatment of IOMM-Lee meningioma cell line with 5-aza-2'-deoxycytidine restored expression of O 6 -methylguanine-DNA methyltransferase and death-associated protein kinase 1, providing evidence that promoter hypermethylation contributes to transcriptional silencing. The frequencies of methylation of any single gene in benign, atypical, and malignant meningiomas were 6% (1/16), 74% (14/19), and 69% (9/13), respectively. Of 48 tumors, 13 (27%) showed that concurrent hypermethylation of two or more genes studied were of atypical or anaplastic type. Statistical analysis revealed that the incidence of promoter hypermethylation of any single gene, of multiple genes, or of glutathione S -transferase P1 was significantly associated with atypical and anaplastic meningiomas ( P < .0001, P = .004, and P = .004, respectively). In conclusion, this study demonstrates that aberrant hypermethylation profile is associated with atypical and anaplastic meningiomas, suggesting that epigenetic change may be involved in malignant progression of meningiomas.

Adult↗

PubMedDate not supplied

The treatment of malignant meningioma with verotoxin.

Malignant meningiomas (MMs) are aggressive intracranial neoplasms with a 75% 5-year recurrence rate. Verotoxin 1 (VT1) is an Escherichia coli toxin, which has recently been shown to have anti-neoplastic action by targeting the globotriosylceramide (Gb(3)) glycolipid on tumor cells and tumor neovasculature. To investigate the potential use of VT1 as a clinical agent for MM, we initially tested 16 meningiomas for Gb(3) expression. Nine of 11 MMs (82%), but only one of five benign meningiomas (20%), were positive for Gb(3). An orthotopic xenograft model was used to test the efficacy of VT1 treatment for MM. We first demonstrated that Gb(3) was highly expressed by the MM cell line, IOMM-Lee, and that this cell line was highly sensitive to VT1 treatment in vitro. A single intratumoral injection of VT1 significantly improved survival in nude mice harboring intracranial tumours (P<.0001). Factor-eight immunostaining of tumours harvested from VT1-treated animals revealed a marked reduction in the tumour microvascular density. In addition, the tumors of VT1-treated animals displayed increased apoptosis by TUNEL analysis and showed a significant decrease in cell proliferation, as determined by MIB-5 immunostaining. VT1 treatment of MM is effective in our orthotopic xenograft model, and warrants further exploration as a potential treatment for these highly anaplastic and aggressive neoplasms.

Animals↗

PubMed2000

Intracranial injection of human meningioma cells in athymic mice: an orthotopic model for meningioma growth.

OBJECT: Although human meningioma cells have been heterotopically implanted in nude mice, introducing these cells into intracranial locations seems more likely to reproduce normal patterns of tumor growth. To provide an orthotopic xenograft model of meningioma, the authors implanted a controlled quantity of meningioma cells at subdural and intracerebral sites in athymic mice. METHODS: Malignant (one tumor), atypical (two tumors), or benign (three tumors) meningiomas were placed into primary cell cultures. Cells (10(6)/10 microl) from these cultures and from an immortalized malignant meningioma cell line, IOMM-Lee, were injected with stereotactic guidance into the frontal white matter or subdural space of athymic mice. Survival curves were plotted for mice receiving tumor cells of each histological type and according to injection site. Other mice were killed at intervals and their heads were sectioned whole. Hematoxylin and eosin staining of these sections revealed the extent of tumor growth. CONCLUSIONS: The median length of survival for mice with malignant, atypical, or benign tumors was 19, 42, or longer than 84 days, respectively. Atypical and malignant tumors were invasive, but did not metastasize extracranially. Malignant tumors uniformly showed leptomeningeal dissemination and those implanted intracerebrally grew locally and spread noncontiguously to the ventricles, choroid plexus, convexities, and skull base. Tumors formed in only 50% of mice injected with benign meningioma cells, whereas injection of more aggressive cells was uniformly successful at tumor production. The three types of human meningiomas grown intracranially in athymic mice maintained their relative positions in the spectrum of malignancy. However, atypical meningiomas became more aggressive after xenografting and acquired malignant features, implying that there had been immune constraint in the original host. Tumor cells injected into brain parenchyma migrated to more optimal environments and grew best there. This model provides insights into the biology of meningiomas and may be useful for testing new therapies.

Aged↗

PubMed2006

RNAi-mediated downregulation of urokinase plasminogen activator and its receptor in human meningioma cells inhibits tumor invasion and growth.

In recent years, RNA interference (RNAi) has emerged as an effective method to target specific genes for silencing. Several groups are actively exploring the use of small interfering RNA (siRNA) for therapeutic applications to treat cancer. Our previous studies have demonstrated the inhibition of various proteases, including serine proteases, cysteine proteases and matrix metalloproteases, via RNA interference (RNAi) in gliomas. Similar to gliomas, malignant meningiomas also exhibit elevated protease levels in comparison to normal brain and benign meningiomas. Here, we used siRNA to simultaneously target urokinase plasminogen activator (uPA) and its receptor, uPAR. A human CMV promoter-driven mammalian expression vector (pU2) was used to produce hairpin double-stranded RNA (hp RNA) to target uPA and uPAR. As determined by Western blotting and fibrin zymography, pU2 effectively inhibited uPAR protein levels and uPA enzymatic activity in meningioma cells (IOMM-Lee). In vitro studies (Matrigel invasion and spheroid migration) revealed reduced meningioma cell invasion and migration. Intratumoral injections of the plasmid vector expressing siRNA for uPA and uPAR resulted in regression of pre-established, subcutaneous tumors in mice. In addition, in vivo studies of mice injected with pU2-transfected meningioma cells revealed inhibition of intracranial tumor formation. These findings suggest that siRNA can be used as a potent and specific therapeutic tool for the treatment of malignant meningiomas in humans.

Animals↗

PubMed2006

Restoration of tissue factor pathway inhibitor inhibits invasion and tumor growth in vitro and in vivo in a malignant meningioma cell line.

Tissue factor pathway inhibitor 2 (TFPI-2) is a 32-kDa extracellular matrix-associated kunitz-type serine proteinase inhibitor. It is secreted by all vascular cells and plays a role in tumor invasion and metastasis, presumably by plasmin-mediated matrix remodeling. Previous studies have shown high expression of TFPI-2 by benign tumors and low or absent expression in highly malignant tumors. Malignant meningiomas constitute 10-15% of all meningiomas and our previous studies revealed loss of expression of TFPI-2 in malignant gliomas. To investigate the role of TFPI-2 in the invasiveness of malignant meningiomas, we stably transfected the human meningioma cell line, IOMM-Lee, with a vector capable of expressing a transcript complementary to the full length of TFPI-2 mRNA in a sense orientation. Restoration of TFPI-2 led to decreased invasiveness of transfected cells compared to parental and vector controls in Matrigel and spheroid assays and inhibition of angiogenesis in in vitro co-cultures with human umbilical vein endothelial cells (HUVEC) and in vivo dorsal skin assay studies. As assessed by Western blotting, we also observed increased expression of BAX, cytochrome c and caspase 3 as well as decreased expression of XIAP (X-linked inhibitor of apoptosis). Finally, TFPI-2 overexpression inhibited intracranial tumor formation in nude mice. Our data substantiate our previous observation that TFPI-2 plays an important role in tumor progression and has potential in anti-cancer therapy.

Animals↗

PubMed2026

Modeling meningioma in vitro in the omics era.

Meningioma biology has been substantially clarified by recent omics-based studies, which have identified recurrent mutations, copy-number alterations, and distinct molecular subgroups. However, although these approaches have provided a valuable framework, they are inherently limited in their ability to establish direct causal relationships. The mechanistic studies are therefore indispensable for translating these molecular observations into biological understanding. Nevertheless, the mechanistic literature has often evolved in a fragmented manner, with individual pathways and model systems studied in relative isolation from the broader multi-omic landscape. In this review, we synthesize these complementary bodies of work into an integrated framework and outline a clear roadmap for future studies. We first review the historical development of established meningioma cell lines, their current molecular characterization, and the recent emergence of 3D models and organoids. Intrinsic challenges in modeling meningioma in vitro are discussed, including the difficulty of establishing immortalized cell lines from predominantly benign tumors, genetic alterations introduced during immortalization, and drift under culture conditions that differ substantially from those of the parental tumors. Next, insights from functional studies centered on these models are integrated within the molecular framework established by large-scale omics analyses. To avoid fragmentation and overemphasis on isolated findings, prior studies are organized into six categories based on major signaling pathways: Hippo, PI3K/Akt/mTOR, MAPK, Wnt/β-catenin, FOXM1, and Notch. Finally, lessons from other cancer models, including experimental approaches to chromosome-scale genomic disturbances, are considered to provide a more integrated view of meningioma biology and to highlight directions for future research.

Meningioma↗