transforming-growth-factor-alpha and Brain-Neoplasms

Treatment of malignant gliomas represents one of the most formidable challenges in oncology. Despite treatment with surgery, radiation therapy, and chemotherapy, the prognosis remains poor, particularly for glioblastoma, which has a median survival of 12 to 15 months. An important impediment to finding effective treatments for malignant gliomas is the presence of the blood brain barrier, which serves to prevent delivery of potentially active therapeutic compounds. Multiple efforts are focused on developing strategies to effectively deliver active drugs to brain tumor cells. Blood brain barrier disruption and convection-enhanced delivery have emerged as leading investigational delivery techniques for the treatment of malignant brain tumors. Clinical trials using these methods have been completed, with mixed results, and several more are being initiated. In this review, we describe the clinically available methods used to circumvent the blood brain barrier and summarize the results to date of ongoing and completed clinical trials.

Topics: Animals; Antineoplastic Agents; Blood-Brain Barrier; Brain; Brain Neoplasms; Catheterization; Drug Delivery Systems; Drug Implants; Exotoxins; Genetic Vectors; Glioblastoma; Glioma; Humans; Immunotoxins; Interleukins; Transferrin; Transforming Growth Factor alpha; Transforming Growth Factor beta; Ultrasonic Therapy

Despite advances in our knowledge about the genesis, molecular biology, and natural history of malignant gliomas and the use of a multi-disciplinary approach to their treatment, patients harboring this diagnosis continue to face a grim prognosis. At the time of diagnosis, patients typically undergo surgery for the establishment of a histologic diagnosis, the reduction of tumor burden, and the relief of mass effect, with the maintenance of the patient's neurological function in mind. This is followed by the administration of adjuvant therapeutics, including radiation therapy and chemotherapy. Many investigational agents with laboratory evidence of efficacy against malignant gliomas have not met their promise in the clinical setting, largely due to the barriers that they must overcome to reach the tumor at a therapeutically meaningful concentration for a durable period of time. The relevant aspects of the blood-brain barrier, blood-tumor barrier, and blood-cerebrospinal fluid barrier, as they pertain to the delivery of agents to the tumor, will be discussed along with the strategies devised to circumvent them. This discussion will be followed by a description of agents currently in preclinical and clinical development, many of which are the result of intense ongoing research into the molecular biology of gliomas.

Topics: Animals; Antineoplastic Agents; Bacterial Toxins; Biological Transport; Blood-Brain Barrier; Brain Neoplasms; Convection; Diphtheria Toxin; Drug Delivery Systems; Exotoxins; Glioma; Humans; Interleukin-13; Interleukin-4; Recombinant Fusion Proteins; Transferrin; Transforming Growth Factor alpha

Targeted toxins represent a new class of agents with high specificity for tumor cells. Toxins in current clinical use for the treatment of brain tumors are mostly recombinant polypeptides consisting of a tumor-selective ligand coupled to a peptide toxin of bacterial origin. Targeted toxins are highly potent - one single molecule of toxin is enough to cause cell death. Toxins are able to kill tumor cells independent of any malignancy-associated genetic alterations and/or mutations. The blood-brain barrier has been a major obstacle for using targeted toxins for treatment of malignant glioma. Convection-enhanced delivery (CED), a method for delivery of large molecules to brain tissue via continuous interstitial microinfusion, has permitted direct administration of toxins to brain tumors or to surrounding brain tissue infiltrated by tumor cells. Four targeted toxins advanced to at least phase II clinical trials and are being used for treatment of adult or pediatric patients with recurrent or progressive malignant glioma. These are IL4-P. aeruginosa exotoxin (IL4-PE, NBI-3001), tumor growth factor (TGF)alpha-P. aeruginosa exotoxin (TP-38), IL13-P. aeruginosa exotoxin (IL13-PE38), and transferrin-C. diphtheriae toxin (TransMID(trade mark), Tf-CRM107). All of these toxins have shown an acceptable profile of toxicity and safety in phase I and II clinical studies and have demonstrated some evidence for tumor response. Current phase I and II clinical protocols are exploring several parameters, such as placement of catheters for CED either intratumorally or in the brain tissue surrounding a tumor, surgical resection of tumor before or after toxin infusion, and single vs. repeated infusion. Two large randomized and controlled phase III multicenter studies using IL13-PE38 or TransMID(trade mark) are currently enrolling patients. This review summarizes the study protocols and key findings of all previously completed and currently ongoing clinical studies with targeted toxins for malignant glioma. It offers in addition an outlook into future areas of development of targeted toxins, such as improved delivery modes and non-invasive in vivo imaging of intracerebral and intratumoral distribution of toxin in patients.

Topics: Animals; Bacterial Toxins; Brain Neoplasms; Clinical Trials as Topic; Drug Delivery Systems; Exotoxins; Glioma; Humans; Immunologic Factors; Immunotoxins; Interleukin-13; Interleukin-4; Recombinant Fusion Proteins; Transferrin; Transforming Growth Factor alpha

Antisense strategy using synthetic oligodeoxynucleotides has been applied to the suppression of specific gene expression, the modulation of various gene expression, and its biological activity. Antisense strategy is applicable for the growth suppression of glioma cells. Several genes, including transforming growth factor-alpha, basic fibroblast growth factor, fibroblast growth factor receptor 1, vascular endothelial growth factor, telomerase, topoisomerase II alpha-subunit, protein kinase C-alpha, and microtubule-associated protein 1A, have been targeted by antisense strategy in glioma cells. These antisense strategies provide a potential novel antitumor therapy for gliomas.

Topics: Brain Neoplasms; Cell Division; Glioma; Humans; Oligonucleotides, Antisense; Receptor Protein-Tyrosine Kinases; Receptor, Fibroblast Growth Factor, Type 1; Receptors, Fibroblast Growth Factor; Telomerase; Transforming Growth Factor alpha; Tumor Cells, Cultured; Vascular Endothelial Growth Factor A

Topics: Animals; Antineoplastic Agents; Brain Neoplasms; Cyclohexanes; Endothelial Growth Factors; Epidermal Growth Factor; Fibroblast Growth Factor 1; Fibroblast Growth Factor 2; Glioma; Humans; Lymphokines; Neovascularization, Pathologic; O-(Chloroacetylcarbamoyl)fumagillol; Prognosis; Sesquiterpenes; Suramin; Transforming Growth Factor alpha; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors

Malignant human gliomas are the most common forms of primary tumors in the central nerve system. Due to their location and invasive nature, treatment so far has been mainly palliative. Thus, understanding the molecular detail of tumor transformation and progression is crucial for developing effective therapeutic strategy for this fetal tumor. Among the genetic alternations found in these tumors, p53 inactivation and PDGF/PDGFR activation represent the early events, and the loss of chromosome 10 and gene amplification and rearrangement of EGFR represent the late events. Studies with both glioma cell lines and primary tumor tissues have strongly suggested that TGF-alpha and EGFR function as an important autocrine loop in supporting proliferation of human glioma, especially in high grade glioma, since elevated TGF-alpha expression is also found in these high grade tumors. Furthermore, down regulation of the expression of TGF-alpha by antisense constructs has been shown to inhibit several types of human tumor cell growth including glioma. Other means of therapeutic approaches using this autocrine loop as a target also include the use of monoclonal antibodies and their cytotoxic conjugated. Considerable understanding of the EGFR-mediated signal transduction pathways has become available recently, which including GRB2/mSOS1 mediated MAP kinase activation; JAK/STATs pathway; PLC-gamma pathway. However, much work still needs to be done before a specific component of these pathways can be applied for effective control of tumor growth in the clinic.

Topics: Animals; Brain Neoplasms; Epidermal Growth Factor; ErbB Receptors; Humans; Receptors, Transforming Growth Factor beta; Transforming Growth Factor alpha

Previous work carried out in the authors' laboratory has shown that LHRH agonists directly inhibit the proliferation of hormone-responsive and hormone-independent human prostatic cancer cell lines (respectively LNCaP and DU145). In addition, the hormone-dependent LNCaP cells respond to a challenge with testosterone with an increase in growth rate. The following experiments have been performed to investigate whether the LHRH agonists might act by interfering with the stimulatory actions of either the EGF/TGF alpha system or androgens. The results obtained in LNCaP and DU145 cells show that LHRH agonists counteract the mitogenic action of the EGF/TGF alpha system. This effect is mediated by a decrease in the concentration of EGF receptors. In addition, in the hormone-dependent LNCaP cells, the treatment with LHRH agonists antagonizes the proliferation promoting effect of testosterone, which in turn appears to be mediated by the activation of the locally expressed EGF/TGF alpha system. Finally, the results suggest the presence in LNCaP cells of a soluble peptidase able to degrade LHRH. In conclusion, the present data suggest an intimate interplay among the actions of LHRH agonists, of androgens and of growth factors, thus, supporting the hypothesis that LHRH agonists may interfere with the EGF/TGF alpha stimulatory loop and with androgens in the control of the proliferation of human prostatic tumors.

Topics: Androgen Antagonists; Androgens; Antineoplastic Agents, Hormonal; Brain Neoplasms; Carcinoma; Cell Division; Endopeptidases; Epidermal Growth Factor; Gonadotropin-Releasing Hormone; Humans; Lymphatic Metastasis; Male; Neoplasm Proteins; Neoplasms, Hormone-Dependent; Prostatic Neoplasms; Somatostatin; Testosterone; Transforming Growth Factor alpha; Tumor Cells, Cultured

Topics: Base Sequence; Brain Neoplasms; Genetic Therapy; Glioma; Humans; Interleukin-8; Molecular Sequence Data; Oligonucleotides, Antisense; Transforming Growth Factor alpha

Current basic research on tumorigenesis suggests that the accumulation of multiple genetic defects underlies the progression of initiated cells toward malignancy. Molecular abnormalities associated with primary brain tumors include a wide variety of changes in tumor-suppressor genes, proto-oncogenes and growth factors. A well-known tumor-suppressor gene, p53 gene, is located on the short arm (p) of chromosome 17 and consists of 11 exons transcribed into a 2.2-2.5 kb messenger (m) RNA that encode for a 53 kDa protein. Its alterations are associated with carcinogenesis of astrocytic tumors. Recent evidence suggests also that the p53 protein may function through promoting the expression of the recently discovered gene, WAF1/Cipl. Loss of chromosome 10 was frequently observed in glioblastoma. Southern blot analysis of glioblastomas revealed that 72% have the chromosome 10 loss and that 38% had amplification of the epidermal growth factor receptor (EGFR) gene. Autocrine stimulation of cell growth requires the presence of both growth factors and their receptors. Other genetic alterations in gliomas include elevated expression of the c-myc, Ha-ras, and c-fos oncogenes with a trend to increase in higher malignant grades.

Topics: Base Sequence; Biomarkers, Tumor; Brain Neoplasms; Chromosome Aberrations; Chromosome Disorders; ErbB Receptors; Gene Expression; Genes, p53; Genes, Tumor Suppressor; Humans; Molecular Sequence Data; Mutagenesis; Neuroglia; Phenotype; Proto-Oncogenes; RNA, Messenger; Transforming Growth Factor alpha

The purpose of this study is to determine the maximum tolerated dose (MTD), dose-limiting toxicity (DLT), and intracerebral distribution of a recombinant toxin (TP-38) targeting the epidermal growth factor receptor in patients with recurrent malignant brain tumors using the intracerebral infusion technique of convection-enhanced delivery (CED). Twenty patients were enrolled and stratified for dose escalation by the presence of residual tumor from 25 to 100 ng/ml in a 40-ml infusion volume. In the last eight patients, coinfusion of (123)I-albumin was performed to monitor distribution within the brain. The MTD was not reached in this study. Dose escalation was stopped at 100 ng/ml due to inconsistent drug delivery as evidenced by imaging the coinfused (123)I-albumin. Two DLTs were seen, and both were neurologic. Median survival after TP-38 was 28 weeks (95% confidence interval, 26.5-102.8). Of 15 patients treated with residual disease, two (13.3%) demonstrated radiographic responses, including one patient with glioblastoma multiforme who had a nearly complete response and remains alive >260 weeks after therapy. Coinfusion of (123)I-albumin demonstrated that high concentrations of the infusate could be delivered >4 cm from the catheter tip. However, only 3 of 16 (19%) catheters produced intraparenchymal infusate distribution, while the majority leaked infusate into the cerebrospinal fluid spaces. Intracerebral CED of TP-38 was well tolerated and produced some durable radiographic responses at doses

Topics: Adult; Aged; Antineoplastic Agents; Brain Neoplasms; ErbB Receptors; Exotoxins; Humans; Immunotoxins; Injections, Intraventricular; Magnetic Resonance Imaging; Maximum Tolerated Dose; Middle Aged; Neoplasm Recurrence, Local; Tomography, Emission-Computed, Single-Photon; Transforming Growth Factor alpha

TP-38 is a recombinant chimeric targeted toxin composed of the EGFR binding ligand TGF-alpha and a genetically engineered form of the Pseudomonas exotoxin, PE-38. After in vitro and in vivo animal studies that showed specific activity and defined the maximum tolerated dose (MTD), we investigated this agent in a Phase I trial. The primary objective of this study was to define the MTD and dose limiting toxicity of TP-38 delivered by convection-enhanced delivery in patients with recurrent malignant brain tumors. Twenty patients were enrolled in the study and doses were escalated from 25 ng/mL to 100 with a 40 mL infusion volume delivered by two catheters. One patient developed Grade IV fatigue at the 100 ng/mL dose, but the MTD has not been established. The overall median survival after TP-38 for all patients was 23 weeks whereas for those without radiographic evidence of residual disease at the time of therapy, the median survival was 31.9 weeks. Overall, 3 of 15 patients, with residual disease at the time of therapy, have demonstrated radiographic responses and one patient with a complete response and has survived greater than 83 weeks.

Topics: Adult; Aged; Brain Neoplasms; Drug Evaluation, Preclinical; Exotoxins; Female; Glioblastoma; Humans; Infusions, Parenteral; Male; Maximum Tolerated Dose; Middle Aged; Pseudomonas aeruginosa; Recombinant Fusion Proteins; Survival Rate; Transforming Growth Factor alpha; Treatment Outcome

Epidermal growth factor family of receptor tyrosine kinases (ERBB) family cell surface receptors, including epidermal growth factor receptor (EGFR/ERBB1), are phosphorylated upon binding by various EGF family ligands and signal via multiple kinase pathways. EGFR signaling is enhanced because of mutational activation of EGFR in almost half of glioblastomas, the most common malignant primary brain tumor. Therapeutic targeting of EGFR in glioblastoma has remained largely unsuccessful. Here, we profiled nine long-term (LTC) and five glioma-initiating (GIC) cell lines for expression and activation of ERBB family receptors and expression of their ligands. Receptors and ligands were abundantly expressed, with patterns overall similar to glioblastoma expression profiles in vivo as deposited in The Cancer Genome Atlas database. No differences between LTC and GIC emerged. Irrespective of ligand or receptor expression, neither an EGFR antibody, erbitux, nor an EGFR tyrosine kinase inhibitor, gefitinib, were particularly active against LTC or GIC at clinically relevant concentrations. Self-renewal capacity of GIC was severely compromised by epidermal growth factor (EGF) withdrawal, but rescued by transforming growth factor alpha (TGF-α), although not by neuregulin-1 (NRG-1). Subcellular fractionation indicated high levels of nuclear phosphorylated EGFR in all LTC and GIC. In LN-229 cells, pERBB2 and pERBB3 were also detected in the nucleus. Nuclear pERBB2 was less sensitive, whereas pERBB3 was induced, in response to gefitinib. This study provides an extensive characterization of human glioma cell models, including stem-like models, with regard to ERBB receptor/ligand expression and signaling. Redundant signaling involving multiple ERBB family ligands and receptors may contribute to the challenges of developing more effective EGFR-targeted therapies for glioblastoma.

Topics: Antineoplastic Agents; Brain Neoplasms; Cell Line, Tumor; Cell Nucleus; Cell Proliferation; Cetuximab; Epidermal Growth Factor; ErbB Receptors; Gefitinib; Glioblastoma; Humans; Ligands; Transforming Growth Factor alpha

EGFRvIII is the most prevalent glioblastoma mutation, occurring in more than 25% of glioblastomas. EGFRvIII cells release microvesicles that contain proteins, miRNAs, and mRNAs that enhance the growth and survival of surrounding tumor cells. However, little is known about the maturation process and regulatory mechanisms of secreted vesicles in EGFRvIII cells.. Signal peptide peptidase (SPP) provides a fascinating mechanism for protein cleavage and subsequent dislocation in the endoplasmic reticulum transmembrane domain.. In this study, we reported that SPP facilitates the secretion of cytokines in vitro and promotes tumor progression in mice. Human cytokine antibody arrays revealed that EGFRvIII secreted higher levels of cytokines, but these levels were significantly reduced following SPP knockdown, suggesting that cytokines in EGFRvIII secretion profiles play important roles in GBM development. Identical results were confirmed in intracellular maturation tracking of TGF-β1 in mouse serum. Clinically, analyses of GBM patient data from the database revealed that HM13 expression was closely related to patient prognosis and survival, suggesting an influence by the secreted vesicles of EGFRvIII tumor cells.. Collectively, our study identifies that SPP affects EGFRvIII secretion profiles and thus promotes tumor progression, providing further understanding of the formation of secreted vesicles and driving role of EGFRvIII in GBM.

Topics: Animals; Aspartic Acid Endopeptidases; Brain Neoplasms; Cell Line, Tumor; Cytokines; Disease Progression; ErbB Receptors; Female; Gene Expression Regulation, Neoplastic; Glioblastoma; Humans; Male; Mice; Mice, Nude; Mutation; RNA, Small Interfering; Signal Transduction; Transfection; Transforming Growth Factor alpha; Transforming Growth Factor beta1

Tumor-associated macrophages (TAMs) are enriched in gliomas and help create a tumor-immunosuppressive microenvironment. A distinct M2-skewed type of macrophages makes up the majority of glioma TAMs, and these cells exhibit pro-tumor functions. Gliomas contain large hypoxic areas, and the presence of a correlation between the density of M2-polarized TAMs and hypoxic areas suggests that hypoxia plays a supportive role during TAM recruitment and induction. Here, we investigated the effects of hypoxia on human macrophage recruitment and M2 polarization. We also investigated the influence of the HIF inhibitor acriflavine (ACF) on M2 TAM infiltration and tumor progression in vivo. We found that hypoxia increased periostin (POSTN) expression in glioma cells and promoted the recruitment of macrophages. Hypoxia-inducible POSTN expression was increased by TGF-α via the RTK/PI3K pathway, and this effect was blocked by treating hypoxic cells with ACF. We also demonstrated that both a hypoxic environment and hypoxia-treated glioma cell supernatants were capable of polarizing macrophages toward a M2 phenotype. ACF partially reversed the M2 polarization of macrophages by inhibiting the upregulation of M-CSFR in macrophages and TGF-β in glioma cells under hypoxic conditions. Administering ACF also ablated tumor progression in vivo. Our findings reveal a mechanism that underlies hypoxia-induced TAM enrichment and M2 polarization and suggest that pharmacologically inhibiting HIFs may reduce M2-polarized TAM infiltration and glioma progression.

Topics: Acriflavine; Animals; Antineoplastic Agents; Brain Neoplasms; Cell Adhesion Molecules; Cell Communication; Cell Plasticity; Cell Proliferation; Chemotaxis; Cytokines; ErbB Receptors; Glioma; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Macrophages; Male; Mice, Inbred BALB C; Mice, Nude; Phosphatidylinositol 3-Kinase; Receptors, Granulocyte-Macrophage Colony-Stimulating Factor; RNA Interference; Signal Transduction; THP-1 Cells; Time Factors; Transfection; Transforming Growth Factor alpha; Transforming Growth Factor beta; Tumor Burden; Tumor Hypoxia; Tumor Microenvironment; Up-Regulation

Brain metastasis is an increasingly common complication for breast cancer patients; approximately 15- 30% of breast cancer patients develop brain metastasis. However, relatively little is known about how these metastases form, and what phenotypes are characteristic of cells with brain metastasizing potential. In this study, we show that the targeted knockdown of MMP-1 in breast cancer cells with enhanced brain metastatic ability not only reduced primary tumor growth, but also significantly inhibited brain metastasis.. Two variants of the MDA-MB-231 human breast cancer cell line selected for enhanced ability to form brain metastases in nude mice (231-BR and 231-BR3 cells) were found to express high levels of matrix metalloproteinase-1 (MMP-1). Short hairpin RNA-mediated stable knockdown of MMP-1 in 231-BR and 231-BR3 cells were established to analyze tumorigenic ability and metastatic ability.. Short hairpin RNA-mediated stable knockdown of MMP-1 inhibited the invasive ability of MDA-MB 231 variant cells in vitro, and inhibited breast cancer growth when the cells were injected into the mammary fat pad of nude mice. Reduction of MMP-1 expression significantly attenuated brain metastasis and lung metastasis formation following injection of cells into the left ventricle of the heart and tail vein, respectively. There were significantly fewer proliferating cells in brain metastases of cells with reduced MMP-1 expression. Furthermore, reduced MMP-1 expression was associated with decreased TGFα release and phospho-EGFR expression in 231-BR and BR3 cells.. Our results show that elevated expression of MMP-1 can promote the local growth and the formation of brain metastases by breast cancer cells.

Topics: Animals; Brain; Brain Neoplasms; Breast Neoplasms; Cell Line, Tumor; ErbB Receptors; Female; Humans; Lung Neoplasms; Matrix Metalloproteinase 1; Mice; Mice, Nude; Neoplasm Metastasis; Transforming Growth Factor alpha; Transplantation, Heterologous

Gliomas, the most frequent primitive central nervous system tumors, have been suggested to originate from astrocytes or from neural progenitors/stem cells. However, the precise identity of the cells at the origin of gliomas remains a matter of debate because no pre-neoplastic state has been yet identified. Transforming growth factor (TGF)-alpha, an epidermal growth factor family member, is frequently overexpressed in the early stages of glioma progression. We previously demonstrated that prolonged exposure of astrocytes to TGF-alpha is sufficient to trigger their reversion to a neural progenitor-like state. To determine whether TGF-alpha dedifferentiating effects are associated with cancerous transforming effects, we grafted intracerebrally dedifferentiated astrocytes. We show that these cells had the same cytogenomic profile as astrocytes, survived in vivo, and did not give birth to tumors. When astrocytes dedifferentiated with TGF-alpha were submitted to oncogenic stress using gamma irradiation, they acquired cancerous properties: they were immortalized, showed cytogenomic abnormalities, and formed high-grade glioma-like tumors after brain grafting. In contrast, irradiation did not modify the lifespan of astrocytes cultivated in serum-free medium. Addition of TGF-alpha after irradiation did not promote their transformation but decreased their lifespan. These results demonstrate that reversion of mature astrocytes to an embryonic state without genomic manipulation is sufficient to sensitize them to oncogenic stress.

Topics: Animals; Astrocytes; Brain Neoplasms; Cell Dedifferentiation; Cell Transformation, Neoplastic; Cells, Cultured; Culture Media, Serum-Free; Gamma Rays; Glioma; Mice; Mice, Inbred C57BL; Mice, Nude; Stem Cell Transplantation; Stem Cells; Stress, Physiological; Transforming Growth Factor alpha

Glioblastoma multiforme remains refractory to conventional therapy, and novel therapeutic modalities are desperately needed. TP-38 is a recombinant chimeric protein containing a genetically engineered form of the cytotoxic Pseudomonas exotoxin fused to transforming growth factor (TGF)-alpha. TGF-alpha binds with high affinity to the epidermal growth factor receptor, which is uniformly overexpressed in malignant gliomas, often because of gene amplification. Prior to therapy with TP-38, the patient described here was completely refractory to multiple other therapies, with radiographic and pathologic evidence of tumor progression. After therapy, she improved clinically, was weaned off steroids and anti-convulsants, and experienced a progressive decrease in enhancing tumor volume. Despite multiple prior recurrences, she has not progressed for >43 months after TP-38 therapy. Small remaining areas of enhancement demonstrate no evidence of tumor histologically and are hypometabolic on positron emission tomography. This report describes a dramatic and sustained clinical and radiographic response in a patient with a bifrontal glioblastoma multiforme treated with intratumoral infusion of a novel targeted toxin, TP-38.

Topics: Brain Neoplasms; Exotoxins; Female; Glioblastoma; Humans; Injections, Intraventricular; Magnetic Resonance Imaging; Middle Aged; Pseudomonas aeruginosa; Recombinant Fusion Proteins; Transforming Growth Factor alpha; Treatment Outcome

To explore the histological structure, angiogenesis, and proliferative activity of central nervous system cavernous hemangiomas.. 70 surgical samples of central nervous system cavernous hemangiomas and 20 normal brain vessel samples from patients of epilepsy and open craniocerebral trauma were stained immunohistochemically with CD34, a-SMA; VEGF, Flt-1; and TGFa, Ki67 respectively. A comparison analysis was made according to the expression intensity.. CD34 and a-SMA were expressed in all the normal control brain vessel tissues in a manner of obvious and continuous staining. VEGF, Flt-1 and TGFa were not expressed obviously in the normal brain tissues. 47 and 50 out of the 70 cavernous hemangioma specimens were positively stained for CD34 and a-SMA respectively, and their expression was less continuous. 68 and 44 out of the 70 cavernous hemangioma specimens were positively stained for VEGF and Flt-1 respectively with diffuse distribution. 68 cavernous hemangioma specimens were positively stained for TGF-a. A significant difference in expression intensity was found for the above 5 factors between the normal control brain tissue and cavernous hemangiomas (all P < 0.05). No expression of Ki67 was detected in all samples.. The biological characteristics of cavernous hemangiomas are mainly relevant to the immaturity of the vessel wall. A series of angiogenic factors play an important role in the development of the lesion. The proliferative activity of the cavernous hemangiomas needs to be studied further.

Topics: Actins; Antigens, CD34; Brain Neoplasms; Endothelial Growth Factors; Extracellular Matrix Proteins; Hemangioma, Cavernous; Humans; Immunohistochemistry; Intercellular Signaling Peptides and Proteins; Ki-67 Antigen; Lymphokines; Transforming Growth Factor alpha; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factor Receptor-1; Vascular Endothelial Growth Factors

Matrix metalloproteinases (MMPs) are a growing family of zinc-dependent endopeptidases that are capable of degrading various components of the extracellular matrix. These enzymes have been implicated in a variety of physiological and pathological conditions including embryogenesis and tumour invasion. The synthesis of many MMPs is thought to be regulated by growth factors, cytokines and hormones. In this study, we investigated the effects of five exogenous growth factors known to be expressed by gliomas [epidermal growth factor (EGF), basic growth factor (bFGF), transforming growth factor beta (TGF-beta1,2) and vascular endothelial growth factor (VEGF)].on MMP-2 and MMP-9 expression in an ependymoma, two grade III astrocytomas, a grade III oligoastrocytoma and a benign meningioma. Zymogram analysis revealed that the effects of the growth factors depended upon the cell lines used in the study. Growth factors generally up-regulated MMP-2 and MMP-9 expression in the gliomas but were least effective in the meningioma; the effect being most prominent with TGF-beta1 and TGF-beta2 in all the cell lines. It is hypothesized that paracrine growth factor interplay may be crucial in the regulation of MMP expression by glioma invasion of the normal brain.

Topics: Brain Neoplasms; Endothelial Growth Factors; Epidermal Growth Factor; Fibroblast Growth Factor 2; Glioma; Growth Substances; Humans; Lymphokines; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Meningeal Neoplasms; Meningioma; Neoplasm Proteins; Transforming Growth Factor alpha; Transforming Growth Factor beta; Tumor Cells, Cultured; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors

The goal of this study was to describe the expression of matrix proteins and angiogenic factors in cerebrovascular malformations.. Forty-six cerebrovascular malformations were immunohistochemically investigated with a battery of staining for five structural proteins (collagen IV, collagen III, smooth muscle actin, fibronectin, and laminin), and three angiogenic factors (vascular endothelial growth factor [VEGF], basic fibroblast growth factor [bFGF], and transforming growth factor alpha [TGFalpha]). The lesions consisted of 34 arteriovenous malformations (AVMs), 10 cavernous malformations (CMs), and 2 venous angiomas. Expression intensity for each histological layer in the abnormal vessel wall was graded and compared.. AVM endothelia and subendothelia expressed more laminin and collagen IV than the same layers of CMs. Conversely, CMs expressed more fibronectin than AVMs. CM endothelia exhibited more prominent staining for smooth muscle actin than AVM endothelia. AVMs and CMs expressed VEGF in the endothelium and subendothelium, and TGFalpha in endothelial and perivascular layers. However, unlike AVMs, CMs expressed bFGF in the endothelium as well. The brain tissue intermingled within AVMs also expressed growth factors. Modified glial cells in the brain tissue adjacent to CMs expressed bFGF and TGFalpha, but not VEGF. Venous angiomas did not express the studied growth factors and mainly consisted of structural proteins of angiogenically mature tissue.. Expression characteristics of structural proteins reveal that AVMs and CMs have different immunohistological properties. This study provides strong confirmation of previous findings of VEGF and bFGF immunoexpression in AVMs and CMs. It adds new information on TGFalpha expression in these malformations and on expression of the angiogenic factors in venous angiomas.

Topics: Actins; Adolescent; Adult; Angiogenesis Inducing Agents; Brain Neoplasms; Child; Collagen; Endothelial Growth Factors; Endothelium, Vascular; Extracellular Matrix Proteins; Female; Fibroblast Growth Factor 2; Fibronectins; Growth Substances; Hemangioma; Hemangioma, Cavernous; Humans; Intracranial Arteriovenous Malformations; Laminin; Lymphokines; Male; Muscle, Smooth, Vascular; Transforming Growth Factor alpha; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors

Transforming growth factor-alpha (TGF-alpha) and its receptor are frequently co-expressed in high-grade astrocytomas, suggesting a role for TGF-alpha autocrine/paracrine loops in the malignant progression of astrocytomas. To identify genes that may be critical in mediating TGF-alpha impact on the malignant progression of astrocytomas, we have used cDNA arrays to investigate TGF-alpha effects on the gene expression profile of U-373 MG glioblastoma cells. We found that in these cells approximately 50% of the TGF-alpha regulated genes code for cell motility/invasion-related proteins. TGF-alpha action on the expression of four of these proteins, alpha-catenin, IQGAP1, RhoA, and cadherin-11, was further investigated by immunoblotting in four astrocytoma cell lines and in normal astrocytes. The results demonstrate that the effects of TGF-alpha on IQGAP1, alpha-catenin, and RhoA expression are cell-line dependent. On the other hand, under TGF-alpha treatment, cadherin-11 expression is consistently decreased in all astrocytoma cell lines tested but is increased in normal astrocytes. In addition, we found that cadherin-11 is consistently down-regulated in astrocytomas versus normal brain tissues. Altogether, these results suggest that the down-regulation of cadherin-11 is a frequent molecular event in the neoplastic transformation of astrocytes and that this down-regulation may be initiated and/or amplified by TGF-alpha autocrine/paracrine loops during tumor progression.

Topics: Animals; Astrocytoma; Brain Neoplasms; Cadherins; Cell Transformation, Neoplastic; Down-Regulation; Gene Expression Regulation, Neoplastic; Glioblastoma; Humans; Oligonucleotide Array Sequence Analysis; Rats; Recombinant Proteins; Transforming Growth Factor alpha

The effects of transforming growth factor-alpha (TGF-alpha) on cell growth were studied in human glioma U251 cells transfected with antisense TGF-alpha vectors (pcDNAI.neo). Several antisense clones showed a marked decrease in growth rate in serum-free medium but not in medium containing 10% FBS, compared with those of parental cells and clones from sense or vector transfectants. Antisense clones also produced fewer and smaller colonies in anchorage-independent growth assays. Moreover, there was a reduction in TGF-alpha expression in these antisense clones at both the protein and mRNA levels, as determined by enzyme linked immuno-sorbent assay and reverse transcriptase polymerase chain reaction analysis. A U251 clone transfected by TGF-alpha antisense in a different vector (pMT/Ep) also showed a marked suppression in cell growth and TGF-alpha mRNA level. Finally, transfected clones with either vector system, showed decreased tumorigenicity in nude mice. In summary, a strong correlation between the inhibition of glioma cell growth and TGF-alpha expression was obtained from two different plasmid vectors, indicating that the expression of TGF-alpha could be specifically and effectively down-regulated by TGF-alpha antisense vector, which in turn led to growth inhibition. These studies suggests that TGF-alpha plays an essential role in controlling human glioma cell proliferation and may serve as a potential target for treatment of malignant glioma.

Topics: Animals; Brain Neoplasms; Cell Division; Clone Cells; Gene Expression Regulation, Neoplastic; Glioma; Humans; Mice; Mice, Nude; Oligodeoxyribonucleotides, Antisense; Protein Biosynthesis; RNA, Messenger; Transcription, Genetic; Transforming Growth Factor alpha; Transplantation, Heterologous; Tumor Cells, Cultured

Fifty-nine paraffin-embedded astrocytic gliomas (four WHO grade 1, 21 WHO grade 2, 17 WHO grade 3 and 17 glioblastomas, WHO grade 4) were immunohistochemically investigated for expression of transforming growth factor-alpha (TGF-alpha), epidermal growth factor receptor (EGF-R) and oncoprotein c-erbB-2 by semiquantitative assessment. Proliferative activity was simultaneously analyzed by using the antibody Ki-67 (MIB-1). Immunostaining in neoplastic cells was quantified by image analysis. Concerning the antibodies used, the percentage of immunoreactive cells increased with histologic malignancy. There was no expression of EGF-R and c-erbB-2 in the majority of low-grade astrocytomas. However, small focal expressions of TGF-alpha and EGF-R were observed in several low-grade astrocytomas (11/25), suggesting an early stimulation of malignant transformation. With regard to percentage, a strong positive correlation between TGF-alpha and EGF-R-stained cells was found, indicating an autocrine stimulation of the mitogenic pathway of the TGF-alpha/EGF-R system. Likewise, indices of EGF-R and c-erbB-2 positive cells correlated significantly. Less significant correlations were also seen between EGF-R, c-erbB-2 frequencies and the Ki-67 labeling index. However, there was no correlation between TGF-alpha and Ki-67 indices. The results suggest that TGF-alpha expression is not directly related to the proliferative potential as judged by the Ki-67 labeling index. Furthermore, besides EGF-R and c-erbB-2, other growth factors and their receptors or mutant EGF-R might participate in the proliferative activity of gliomas.

Topics: Astrocytoma; Brain Neoplasms; Cell Count; Cell Division; ErbB Receptors; Glioblastoma; Humans; Image Processing, Computer-Assisted; Immunoenzyme Techniques; Ki-67 Antigen; Mitotic Index; Receptor, ErbB-2; Transforming Growth Factor alpha

To study the effect of antisense oligodeoxynucleotide(ON) of TGF alpha on its gene expression in TJ 905 cell line.. Antisense and sense TGF alpha phosphorothioate ON (SON) and random SON were synthesized and transfected to TJ 905 cells mediated by lipofectin. Their effects on the TGF alpha gene expression were examined by in situ hybridization of TGF alpha mRNA, immunohistochemical study and cell count.. (1) TGF alpha antisense SON could significantly inhibit the growth of TJ 905 cell line. The inhibition peaked at 24 hour after transfection, the inhibition rate reached 68% at 20 microM, and the effect decreased 72 hours after transfection. The inhibition effect was dose dependent. (2) Antisense TGF alpha SON inhibited TGF alpha expressions at both mRNA and protein levels.. Antisense TGF alpha SON can inhibit the expressions of TGF alpha and markedly inhibit cell growth of human glioma TJ 905 cell line. TGF alpha contributes in the growth potential of glioma.

Topics: Brain Neoplasms; Cell Division; Gene Expression; Glioblastoma; Humans; Oligodeoxyribonucleotides, Antisense; RNA, Messenger; Transforming Growth Factor alpha; Tumor Cells, Cultured

Alterations in the epidermal growth factor receptor (EGFR) and its main ligand, transforming growth factor-alpha (TGF alpha), were investigated for a possible prognostic relevance in 125 astrocytic gliomas (44 World Health Organization (WHO) Grade II, 19 WHO Grade III, and 62 WHO Grade IV tumors). The TGF alpha and EGFR proteins were detected immunohistochemically using monoclonal antibodies. A positive immunoreaction to TGF alpha was detected in 33 (75%) of 44 WHO Grade II astrocytomas, 18 (95%) of 19 WHO Grade III astrocytoma, and 50 (81%) of 62 WHO Grade IV glioblastomas. No correlation between TGF alpha immunoreaction and duration of survival could be found. A positive EGFR immunoreaction was detected in seven (16%) of 44 WHO Grade II astrocytomas, five (26%) of 19 WHO Grade III astrocytomas, and 32 (52%) of 62 WHO Grade IV glioblastomas. Of these gliomas, 97 (26 WHO Grade II, 17 WHO Grade III, and 54 WHO Grade IV gliomas) were examined for EGFR gene amplification using a differential polymerase chain reaction assay. Amplification of the EGFR gene was detected in none of the WHO Grade II astrocytomas, one (6%) of 17 WHO Grade III astrocytomas, and 18 (33%) of 54 WHO Grade IV glioblastomas. Twenty-two of the tumors investigated showed a positive EGFR immunoreaction without detectable gene amplification (five WHO Grade II, four WHO Grade III, and 13 WHO Grade IV tumors). Gene amplification was invariably associated with a positive EGFR immunoreaction. For the entire study group, a strong correlation between EGFR alterations (gene amplification and positive immunoreaction) and survival could be found. However, this correlation only reflected the higher percentages of cases with EGFR alterations in malignant gliomas and was not an independent prognostic factor as determined by multifactorial analysis. These data demonstrate that EGFR alterations are frequent events in astrocytic gliomas and are largely restricted to glioblastomas. However, within one tumor grade they do not provide prognostic information.

Topics: Adult; Brain Neoplasms; ErbB Receptors; Female; Glioma; Humans; Immunohistochemistry; Male; Polymerase Chain Reaction; Prognosis; Transforming Growth Factor alpha

Morphological and immunocytological changes of intermediate filaments of cultured human malignant glioma cells were studied by adding various growth factors or cytokines using stereoscopic high voltage electron microscopy operated at 1,000 kV. The gold-colloid immuno-cytochemical method was used to stain GFAP and vimentin. Growth rate of tumor cells increased when EGF, TGF-alpha, and PDGF administered and decreased when FGF, TNF, and CLN-IgG administered. Morphological changes of cells were not remarkable when EGF, PDGF, IL-1, and FGF were administered. The cytoplalsmic organellaes were damaged after administrating TNF and CLN-IgG to cells.

Topics: Brain Neoplasms; Cell Division; Cytokines; Epidermal Growth Factor; Glial Fibrillary Acidic Protein; Glioma; Growth Substances; Humans; Immunohistochemistry; Intermediate Filaments; Microscopy, Immunoelectron; Organelles; Platelet-Derived Growth Factor; Transforming Growth Factor alpha; Tumor Cells, Cultured; Vimentin

Transforming growth factor-alpha (TGF-alpha)-mediated autocrine regulation in human non-small-cell lung cancer (NSCLC) cells NCI-H226 and its brain metastatic variant H226Br were compared. An enhanced TGF-alpha-induced dose-dependent mitogenic responsiveness in H226Br cells was observed. Neutralising antibody that binds TGF-alpha inhibits H226Br cell growth more effectively than NCI-H226 cell growth. Binding assay with 125I-labelled epidermal growth factor (EGF) revealed that H226Br has two types of EGF receptors (EGFRs), whereas the parental cell line, NCI-H226, has only one. H226Br cells contain twice as many EGFRs as H226 cells, as proved by Scatchard analysis and immune kinase assay. Northern analysis indicated that there is more EGFR transcript in H226Br than in NCI-H226, indicating a transcriptional EGFR gene elevation during metastasis progression. The level of accumulated immunoactive TGF-alpha is lower in the conditioned medium of H226Br than in that of NCI-H226. demonstrating down-regulation of TGF-alpha transcript. The accumulated data suggest an elevated and sensitive autocrine modulation by TGF-alpha and EGFR in immortalising the brain metastatic variant cells that were derived from a human NSCLC squamous cell line.

Topics: Animals; Brain Neoplasms; Carcinoma, Non-Small-Cell Lung; Cell Division; ErbB Receptors; Humans; Lung Neoplasms; Mice; Mice, Nude; Phosphorylation; Polymerase Chain Reaction; RNA; Transforming Growth Factor alpha; Tumor Cells, Cultured

To examine which growth factors correlate with neovascularization in human brain tumors, the mRNA levels of transforming growth factor alpha, transforming growth factor beta, basic fibroblast growth factor, and vascular endothelial growth factor (VEGF) genes were determined by a Northern blot analysis in surgically obtained human gliomas and meningiomas. The vascular development was determined by counting the number of microvessels which were immunostained with von Willebrand factor. We normalized the growth factor mRNA levels versus the glyceraldehyde phosphate dehydrogenase mRNA level. In the 17 gliomas and 16 meningiomas examined, the mRNA of transforming growth factors alpha and beta, basic fibroblast growth factor, and VEGF were expressed at various levels. Among those 4 growth factors, the mRNA levels of VEGF, but not those of transforming growth factors alpha and beta and basic fibroblast growth factor, correlated significantly with vascularity in both gliomas (correlation coefficient r = 0.499; P < 0.05) and meningiomas (correlation coefficient r = 0.779; P < 0.001). These findings thus suggest that VEGF may be a positive factor in tumor angiogenesis in both human gliomas and meningiomas.

Topics: Brain Neoplasms; Endothelial Growth Factors; Fibroblast Growth Factor 2; Glioma; Humans; Lymphokines; Meningioma; Neovascularization, Pathologic; RNA, Messenger; Transforming Growth Factor alpha; Transforming Growth Factor beta; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors

The expression of epidermal growth factor receptor (EGFR) and the pre-pro form of one of its ligands, transforming growth factor-alpha (TGF-alpha), was studied by Northern blotting in a series of 14 capillary hemangioblastomas of the central nervous system. A constant coexpression of EGFR and pre-pro-TGF-alpha mRNAs was found. Immunocytochemical investigation of an extended series of 51 capillary hemangioblastomas revealed that the stromal cells in these tumors showed immunoreactivity with monoclonal antibodies to EGFR and TGF-alpha. Analysis of gene dosage by Southern blotting in 20 tumors indicated a normal gene copy number of EGFR and TGF alpha in all cases. Our findings suggest that autocrine and/or juxtacrine growth stimulation via the EGFR may contribute to tumor growth in capillary hemangioblastomas.

Topics: Adolescent; Adult; Aged; Blotting, Northern; Blotting, Southern; Brain Neoplasms; Capillaries; ErbB Receptors; Female; Hemangioblastoma; Humans; Immunohistochemistry; Male; Middle Aged; Molecular Sequence Data; RNA, Messenger; Transforming Growth Factor alpha

In 75 gliomas and 31 meningiomas, mutations at the epidermal growth factor receptor (EGFR) gene locus were restricted to gliomas. The ligands of this receptor, epidermal growth factor and transforming growth factor alpha, lacked quantitative changes at their loci in gliomas and meningiomas. EGFR gene amplification occurred in astrocytomas, oligodendrogliomas, ependymomas and glioblastomas. The frequency of this mutation significantly increased with the malignancy grade and the patient's age. Especially in glioblastomas of individuals aged over 64 years, EGFR gene mutations were observed without chromosome-10-specific allele losses. This finding contradicts the hypothesis that deletion of one entire chromosome 10 regularly precedes EGFR gene amplification in primary glioblastomas of patients aged over 50 years. It was found that most individuals whose gliomas carry an EGFR gene mutation have a poor prognosis, comparable to that of glioblastoma patients even when the tumour is graded as benign.

Topics: Adolescent; Adult; Aged; Brain Neoplasms; Child; Child, Preschool; Chromosome Mapping; Epidermal Growth Factor; ErbB Receptors; Female; Gene Amplification; Glioblastoma; Glioma; Humans; Male; Meningeal Neoplasms; Meningioma; Middle Aged; Mutation; Prognosis; Remission Induction; Survival Rate; Transforming Growth Factor alpha

Loss of genetic material on chromosome 10 is regarded as a prominent feature in the genesis of glioblastomas. To use chromosome 10 deletions as diagnostic markers for glioblastomas we investigated, if the loss of chromosome 10 material could be restricted on the region 10q21-26. By PCR microsatellite analysis on frozen tissue and paraffin material from the ZULCH brain tumor collection we found (1) loss of heterozygosity in 10q21-26 in 75% of the investigated DNA from frozen tissue and (2) an interstitial loss in the region of the microsatellite marker D10S186. The combined immunohistochemical analysis of overexpression of EGFR, EGF and TGF alpha with LOH on chromosome 10 showed that chromosome 10 deletions are not exclusively bound to EGFR overexpression.

Topics: Brain Neoplasms; Chromosome Deletion; Chromosome Mapping; Chromosomes, Human, Pair 10; DNA, Neoplasm; DNA, Satellite; Epidermal Growth Factor; ErbB Receptors; Gene Expression; Glioblastoma; Glioma; Humans; Immunohistochemistry; Paraffin; Polymerase Chain Reaction; Transforming Growth Factor alpha

Topics: Astrocytoma; Brain Neoplasms; Cell Transformation, Neoplastic; DNA Mutational Analysis; DNA, Neoplasm; ErbB Receptors; Genes, p53; Glioblastoma; Humans; Life Tables; Neoplasm Proteins; Neoplasm Recurrence, Local; Nerve Tissue Proteins; Oncogenes; Polymorphism, Genetic; Prognosis; Survival Analysis; Transforming Growth Factor alpha; Tumor Suppressor Protein p53

Epidermal growth factor receptor (EGFR) is amplified or overexpressed in many malignant gliomas and other primary brain tumors but is low or undetectable in normal brain. In the present study, this differential expression has been exploited for targeted brain tumor therapy using a TGF-alpha-Pseudomonas exotoxin recombinant toxin, TGF-alpha-PE38. In vitro experiments demonstrate that the cytotoxicity of this fusion protein is primarily determined by tumor EGFR expression and that TGF-alpha-PE38 cytotoxicity is abolished by pretreatment with excess epidermal growth factor. Treatment with i.p. TGF-alpha-PE38 in nude mice bearing glioblastoma or medulloblastoma s.c. xenografts produced tumor regression and growth delay. For intracranial xenograft implants treated with i.p. TGF-alpha-PE38, significant increases in median survival were noted only for tumors with the highest EGFR expression. However, intracranial tumors treated with a single intratumoral injection of TGF-alpha-PE38 showed increased survival in all xenografts tested. These results indicate that TGF-alpha-PE38 is active against primary human brain tumors ranging from moderate to high EGFR expression. For intracranial tumors, however, the higher survival rates produced by intracranial injection of TGF-alpha-PE38 than by continuous i.p. administration suggest that increased drug clearance or impaired drug delivery reduces the efficacy of systemic TGF-alpha-PE38. Direct delivery of TGF-alpha-PE38 into brain tumors by controlled-release biodegradable polymers or intratumoral implanted catheters, or intrathecal administration into the colony stimulating factor of patients with leptomeningeal metastasis, may represent clinically useful applications of recombinant toxin therapy in tumors with high EGFR expression.

Topics: Animals; Antineoplastic Agents; Brain Neoplasms; ErbB Receptors; Exotoxins; Female; Glioma; Humans; Medulloblastoma; Mice; Mice, Nude; Neoplasm Transplantation; Recombinant Fusion Proteins; Transforming Growth Factor alpha; Transplantation, Heterologous; Tumor Cells, Cultured

The effects of 5 different growth factors [EGF, PDGF(bb), TGF-alpha, bFGF and IL-2] were studied on tumour spheroids obtained from 5 different human glioma cell lines (U-251MG, D-263MG, D-37MG, D-54MG, GaMG). The expression of EGF and PDGF receptors as well as the endogenous production of TGF-alpha and PDGF were studied by Northern blot analyses. After growth-factor-exposure, tumour spheroid volume growth, and directional cell migration from the spheroids were studied. In addition, tumour-cell invasion was studied in vitro, where foetal rat-brain aggregates were used as a target for the tumour cells. In all the assays a common stimulator for most of the cell lines was EGF. The other growth factors had a more heterogeneous stimulatory effect. Tumour-cell invasion, cell growth and cell migration are biological properties which are not necessarily related to each other. This may explain why the tumours often responded differently to the growth factors in the various assay systems. Two of the cell lines studied were non-invasive (U-251MG, D-263MG). It is shown that these were stimulated both in the directional migration assay and in the spheroid-volume-growth assay. However, their non-invasive behaviour was not influenced by the growth factors studied.

Topics: Animals; Blotting, Northern; Brain; Brain Neoplasms; Cell Aggregation; Cell Division; Cell Movement; Epidermal Growth Factor; Fibroblast Growth Factor 2; Glioma; Growth Substances; Interleukin-2; Neoplasm Invasiveness; Phenotype; Platelet-Derived Growth Factor; Rats; Receptors, Growth Factor; RNA, Messenger; Transforming Growth Factor alpha; Tumor Cells, Cultured

A role for neutral endopeptidase 24.11 (NEP) in growth and development is supported by the demonstration that NEP hydrolyses and inactivates a number of peptide growth factors including atrial natriuretic peptide, endothelins, bombesin-like peptides, and opioid peptides, including the enkephalins. In the present study, suspensions of cells obtained from the ventral mesencephalon or cortex of rat embryos (ED14) were implanted into the striatum of the adult rat brain. Three to 15 weeks after transplantation the relative distribution of NEP-positive cellular elements was visualized histochemically. NEP staining in the transplants consistently appeared before NEP staining in the surrounding host striatum supporting a relative increase in NEP activity in the transplants. The NEP staining richly visualized cells of varying size and morphology which lacked the normal organization of the host striatum. The histochemical staining in the transplants and the surrounding host tissue was completely blocked by a 100 nM concentration of the selective NEP inhibitors phosphoramidon or JHF-26, supporting the exclusive localization of NEP by this method. NEP localization in the embryonic (ED14) cortex and ventral mesencephalon was also confirmed, suggesting one possible origin for the NEP-positive cells visualized in the transplants. Fluorescent double-labeling studies for NEP and glial fibrillary acidic protein (GFAP) or transforming growth factor alpha precursor (TGF alpha p) revealed the presence of rich glial labeling within the transplants for both GFAP and TGFap. NEP-labeled cells in the transplants were closely associated with glial elements, however, only occasional glial elements in the transplants stained for NEP; supporting a non-astrocytic localization for the NEP in the transplants. The marked enhancement of NEP staining in the transplants may have significance for controlling the rate or pattern of growth of the transplanted cells through inactivation of peptide growth factors produced by, or in response to, the transplants.

Topics: Animals; Brain Neoplasms; Brain Tissue Transplantation; Cerebral Cortex; Corpus Striatum; Female; Fetal Tissue Transplantation; Fluorescence; Glial Fibrillary Acidic Protein; Glioma; Immunohistochemistry; Male; Mesencephalon; Neoplasm Transplantation; Neprilysin; Pregnancy; Rats; Rats, Sprague-Dawley; Transforming Growth Factor alpha

Astrocytomas are highly malignant brain tumors and are among the most neovascularized solid tumors. We have investigated the expression of the angiogenic growth factors acidic fibroblast growth factor and transforming growth factor-alpha, together with its receptor epidermal growth factor receptor, in 30 primary astrocytomas. Both acidic fibroblast growth factor and transforming growth factor-alpha, together with epidermal growth factor receptor, are found to be greatly overexpressed in these tumors when compared with normal brain. This overexpression of angiogenic growth factors may underlie the intense neovascularization characteristic of astrocytomas.

Topics: Angiogenesis Inducing Agents; Astrocytoma; Blotting, Northern; Brain Neoplasms; ErbB Receptors; Fibroblast Growth Factor 1; Humans; Immunohistochemistry; Neovascularization, Pathologic; Nucleic Acid Hybridization; RNA, Messenger; Transforming Growth Factor alpha

Ribonucleic acid was isolated from a wide spectrum of central nervous system tumors to examine the expression of platelet-derived growth factors (PDGF) A and B, tumor growth factors (TGF-beta) 1 and 2, and ros messenger ribonucleic acid. Eight glioblastoma cell lines were examined as well as cell cultures from 22 tumor explants. The explants included 6 glioblastomas, 4 anaplastic astrocytomas, 5 astrocytomas, 3 ependymal tumors, 2 meningiomas, 1 medulloblastoma. and 1 ganglioglioma. For comparison, 2 nontumor glial cell cultures were included. The PDGF B-chain was expressed in 5 of 8 glioblastoma cell lines, 2 of 6 glioblastomas, and in 3 of 4 anaplastic astrocytoma explants. There was no PDGF B expression in 4 astrocytomas, 3 ependymomas of varying malignancy, in the remainder of the tumors, or in the nontumor glial cells. The PDGF A-chain was expressed in all of the tumors, with the exception of the malignant ependymoma and in both nontumor glial cell cultures. TGF-beta 1 was expressed in all of the tumors and in nontumor glial cells. The expression of TGF-beta 2 was expressed in many of the benign and malignant tumors and also in both nontumor glial cell cultures. The ros messenger ribonucleic acid was expressed in 1 of 5 glioblastoma cell lines and in 2 of 6 glioblastoma cell explants, but in none of the other tumors or in the nontumor glial cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Brain Neoplasms; Endothelial Growth Factors; Gene Expression Regulation, Neoplastic; Humans; Nucleic Acid Hybridization; Platelet-Derived Growth Factor; Protein-Tyrosine Kinases; Proto-Oncogene Proteins; Receptor Protein-Tyrosine Kinases; RNA, Messenger; RNA, Neoplasm; Transforming Growth Factor alpha; Transforming Growth Factor beta; Tumor Cells, Cultured

Anomalies of the epidermal growth factor receptor (EGFR) gene, including amplification, rearrangement, and overexpression, have been reported in malignant human gliomas in vivo. In vitro glioma cell lines coexpress EGFR and at least one of its ligands, transforming growth factor alpha, suggesting the existence of an autocrine growth stimulatory loop. We have studied the tumor tissue from 62 human glioma patients and examined the structure and quantity of the EGFR gene and its transcripts, as well as the quantity of the receptor protein. In addition we have examined the genes and transcripts coding for the pre-pro forms of epidermal growth factor and transforming growth factor alpha, the two endogenous EGFR ligands. EGFR gene amplification was detected in 16 of the 32 malignancy grade IV gliomas (glioblastoma) studied (50%), but only in 1 of 30 gliomas of lesser malignancy grade (I-III). All tumors with an amplified gene overexpressed EGFR mRNA. More than one-half (62.5%) of the glioblastomas with amplified EGFR genes also showed coamplification of rearranged EGFR genes and concomitant expression of aberrant mRNA species. Overexpression, without gene amplification, was observed in some of the low grade gliomas, and aberrant EGFR transcripts were also seen in some cases without gene amplification or detected gene rearrangements. mRNA expression for one or both of the pre-pro forms of the ligands was detected in every tumor studied. Thus, several mechanisms for the activation of the EGFR-mediated growth stimulating pathway are possible in human gliomas in vivo: expression of a structurally altered receptor that may have escaped normal control mechanisms; and/or auto-, juxta-, or paracrine stimulating mechanisms involving coexpression of receptor and ligands, with or without overexpression of the receptor.

Topics: Adolescent; Adult; Aged; Brain Neoplasms; Epidermal Growth Factor; ErbB Receptors; Female; Gene Expression Regulation, Neoplastic; Glioma; Humans; Male; Middle Aged; RNA, Messenger; RNA, Neoplasm; Transforming Growth Factor alpha

Expression of transforming growth factor alpha (TGF alpha) is frequently associated with the development of human and animal tumors. Using a sensitive immunohistochemical assay, which can be applied on formalin-fixed, paraffin-embedded tissue, we have examined the expression of TGF alpha in 71 human gliomas (63 untreated and 8 recurrent tumors). Tumors were graded by a 3-grade-system: grade I = low grade gliomas, grade II = anaplastic gliomas and grade III = glioblastomas. A strong positive correlation between tumor grade and extent of TGF alpha expression was found (P less than 0.0001). Polymerase chain reaction (PCR) was used to amplify the fourth exon of the TGF alpha gene of 8 glioma DNA specimens and increasing amounts of normal human DNA, which served as a standard. No amplification of the TGF alpha gene copy number in tumors could be detected.

Topics: Base Sequence; Brain Neoplasms; DNA, Neoplasm; Gene Amplification; Gene Expression Regulation, Neoplastic; Glioma; Humans; Immunohistochemistry; Molecular Sequence Data; Polymerase Chain Reaction; Transforming Growth Factor alpha