losartan-potassium and Glioblastoma

The growth of malignant tumors is influenced by their microenvironment. Glioblastoma, an aggressive primary brain tumor, may have cysts containing fluid that represents the tumor microenvironment. The aim of this study was to investigate whether the cyst fluid of cystic glioblastomas contains growth-stimulating factors. Identification of such growth factors may pave the way for the development of targeted anti-glioblastoma therapies.. We performed hormone analysis of cyst fluid from 25 cystic glioblastomas and proteomics analysis of cyst fluid from another 12 cystic glioblastomas.. Glioblastoma cyst fluid contained hormones within wide concentration ranges: Insulin-like growth factor 1 (0-13.7 nmol/L), insulin (1.4-133 pmol/L), erythropoietin (4.7-402 IU/L), growth hormone (0-0.93 µg/L), testosterone (0.2-10.1 nmol/L), estradiol (0-1.0 nmol/L), triiodothyronine (1.0-11.5). Tumor volume correlated with cyst fluid concentrations of growth hormone and testosterone. Survival correlated inversely with cyst fluid concentration of erythropoietin. Several hormones were present at concentrations that have been shown to stimulate glioblastoma growth in vitro. Concentrations of erythropoietin and estradiol (in men) were higher in cyst fluid than in serum, suggesting formation by tumor or brain tissue. Quantitatively, glioblastoma cyst fluid was dominated by serum proteins, illustrating blood-brain barrier leakage. Proteomics identified several proteins that stimulate tumor cell proliferation and invasiveness, others that inhibit apoptosis or mediate adaption to hypoxia and some that induce neovascularization or blood-brain barrier leakage.. The microenvironment of glioblastomas is rich in growth-stimulating factors that may originate from the circulation, the tumor, or the brain. The wide variation in cyst fluid hormone concentrations may differentially influence tumor growth.

Topics: Erythropoietin; Estradiol; Glioblastoma; Growth Hormone; Humans; Male; Testosterone; Tumor Microenvironment

Malignant gliomas are aggressive spinal cord tumors. In this study, we hypothesized that combination therapy using an anti-angiogenic agent, bevacizumab, and hypoxia-inducible glioblastoma-specific suicide gene could reduce tumor growth.. In the present study, we evaluated the effect of combination therapy using bevacizumab and pEpo-NI2-SV-TK in reducing the proliferation of C6 cells and tumor growth in the spinal cord. Spinal cord tumor was generated by the injection of C6 cells into the T5 level of the spinal cord. Complexes of branched polyethylenimine (bPEI)/pEpo-NI2-SV-TK were injected into the spinal cord tumor. Bevacizumab was then administered by an intraperitoneal injection at a dose of 7 mg/kg. The anti-cancer effects of combination therapy were analyzed by histological analyses and magnetic resonance imaging (MRI). The Basso, Beattie and Bresnahan scale scores for all of the treatment groups were recorded every other day for 15 days to assess the rat hind-limb strength.. The complexes of bPEI/pEpo-NI2-SV-TK inhibited the viability of C6 cells in the hypoxia condition at 5 days after treatment with ganciclovir. Bevacizumab was decreased in the cell viability of human umbilical vein endothelial cells. Combination therapy reduced the tumor size by histological analyses and MRI. The combination therapy group showed improved hind-limb function compared to the other groups that were administered pEpo-NI2-SV-TK alone or bevacizumab alone.. This study suggests that combination therapy using bevacizumab with the pEpo-NI2-SV-TK therapeutic gene could be useful for increasing its therapeutic benefits for intramedullary spinal cord tumors.

Topics: Angiogenesis Inhibitors; Animals; Bevacizumab; Cell Line, Tumor; Cell Proliferation; Combined Modality Therapy; Endothelial Cells; Enhancer Elements, Genetic; Erythropoietin; Genes, Reporter; Genes, Transgenic, Suicide; Glioblastoma; Glioma; Hindlimb; Injections, Intraperitoneal; Magnetic Resonance Imaging; Rats; Spinal Cord Neoplasms

Glioblastoma multiforme (GBM) is the most common primary brain tumor characterized with poor prognosis and short survival. In addition to the standard treatment protocols, targeted molecular treatment options are under trial. In the recent trials, erythropoietin and erythropoietin receptor were found to be linked with the progression of GBM cells.. In this study, we compared the expression of EPOR with survival in GBM patients with mortality.. Twenty-six patients operated for GBM in 2012-2014 were enrolled in this study. Tumor tissues were stained with EPOR, epidermal growth factor receptor, vascular endothelial growth factor, and assigned as (1+), (2+), and (3+) according to their immunohistochemical staining levels. The average postoperative follow-up time was 9.3 months. Kaplan-Meier's survival test and Spearman's correlation test were used in statistical analysis.. EPOR 1(+) stained group showed a median survival of 8 months (95% confidence interval [CI]: 0.954-15.046). EPOR 2(+) stained group showed a median survival of 6 months (95% CI: 2.901-9.090) EPOR 3(+) stained group showed a median survival of 2 months (95% CI: 0.400-3.600). (Kaplan-Meier P = 0.002).. These results portrayed that EPOR staining levels were inversely proportional with average survival time. In the future, specific inhibitors of this molecule could be used to form a novel treatment option for GBM.

Topics: Adult; Aged; Aged, 80 and over; Brain Neoplasms; Disease Progression; ErbB Receptors; Erythropoietin; Female; Follow-Up Studies; Glioblastoma; Humans; Immunohistochemistry; Kaplan-Meier Estimate; Male; Middle Aged; Prognosis; Receptors, Erythropoietin; Survival Rate; Vascular Endothelial Growth Factor A

Erythropoietin (EPO) is an erythropoiesis stimulating growth factor and hormone. EPO has been widely used in the treatment of chronic renal failure, cancer, and chemotherapy-related anemia for three decades. However, many clinical trials showed that EPO treatment may be associated with tumorigenesis and cancer progression. EPO is able to cross blood-brain barriers, and this may lead to an increased possibility of central nervous system tumors such as glioblastoma. Indeed, EPO promotes glioblastoma growth and invasion in animal studies. Additionally, EPO increases glioblastoma cell survival, proliferation, migration, invasion, and chemoresistancy in vitro. However, the exact mechanisms of cancer progression induced by EPO treatment are not fully understood. Posttranscriptional gene regulation through microRNAs may contribute to EPO's cellular and biological effects in tumor progression. Here, we aimed to study whether tumor suppressive microRNA, miR-451, counteracts the positive effects of EPO on U87 human glioblastoma cell line. Migration and invasion were evaluated by scratch assay and transwell invasion assay, respectively. We found that EPO decreased basal miR-451 expression and increased cell proliferation, migration, invasion, and cisplatin chemoresistancy in vitro. miR-451 overexpression by transfection of its mimic significantly reversed these effects. Furthermore, ectopic expression of miR-451 inhibited expression of its own target genes, such as metalloproteinases-2 and -9, which are stimulated by EPO treatment and involved in carcinogenesis processes, especially invasion. These findings suggest that miR-451 mimic delivery may be useful as adjuvant therapy in addition to chemotherapy and anemia treatment by EPO and should be tested in experimental glioblastoma models.

Topics: Antineoplastic Agents; Cell Line, Tumor; Cell Movement; Cisplatin; Drug Resistance, Neoplasm; Erythropoietin; Gene Expression Regulation, Neoplastic; Glioblastoma; Humans; MicroRNAs; Neoplasm Invasiveness; Polyenes; Recombinant Proteins

Hemoglobin is produced mainly in erythroid cells. However, it has been reported in non-erythroid cells of human and rodents. We have shown previously that neuroglobin, cytoglobin and hemoglobin are expressed in human glioblastoma multiforme (GBM) cells. We sought to determine whether hemoglobin expression is upregulated by hypoxia, and whether its expression is restricted to the cancer stem cell populations in different GBM cell lines or GBM brain tumor initiating cells (BTICs). Flow cytometry, magnetic cell sorting and qRT-PCR were used to examine the hypoxic upregulation of hemoglobins as well as erythropoietin (EPO) and erythropoietin receptor (EPOR) in GBM cell lines (M006x, M059J, M059K, U87R and U87T) and GBM-BTICs. The data showed significantly increased expression in globins (α, β, γ, δ, ζ and ε), EPO and EPOR mRNA levels under hypoxia. Globin expression is not limited to the stem cell populations or GBM-BTICs but is a property of the entire GBM population. We assumed that the total expression of mRNA of different normalized globins (α, β, γ, δ, ζ and ε) at different time‑points for the same cell line is 100%. Under aerobic conditions, ε globin was predominantly expressed, and then decreased gradually with increasing time in hypoxia. This was coupled to a concomitant increase in α and γ globins. Our findings suggest that hypoxic upregulation of hemoglobin expression in GBM cells may be a part of a repertoire of active defence and adaptation mechanisms enabling these cells to acquire resistance to aggressive multimodality treatments of chemotherapy and radiotherapy. New therapeutic strategies to interfere with hemoglobin expression or function in GBM cells are required.

Topics: Brain Neoplasms; Cell Hypoxia; Erythropoietin; Gene Expression Regulation, Neoplastic; Glioblastoma; Hemoglobins; Humans; Neoplastic Stem Cells; Receptors, Erythropoietin

Gene therapy has been considered a promising approach for glioblastoma therapy. To avoid side effects and increase the specificity of gene expression, gene expression should be tightly regulated. In this study, glioma and hypoxia dual-specific plasmids (pEpo-NI2-SV-Luc and pEpo-NI2-SV-HSVtk) were developed by combining the erythropoietin (Epo) enhancer and nestin intron 2 (NI2). In the in vitro studies, pEpo-NI2-SV-Luc showed higher gene expression under hypoxia than normoxia in a glioblastoma-specific manner. The MTT and caspase assays demonstrated that pEpo-NI2-SV-HSVtk specifically induced caspase activity and cell death in hypoxic glioblastoma cells. For in vivo evaluation, subcutaneous and intracranial glioblastoma models were established. Dexamethasone-conjugated-polyethylenimine (PEI-Dexa) was used as a gene carrier, since PEI-Dexa efficiently delivers plasmid to glioblastoma cells and also has an antitumor effect due to the effect of dexamethasone. In the in vivo study in the subcutaneous and intracranial glioblastoma models, the tumor size was reduced more effectively in the pEpo-NI2-SV-HSVtk group than in the control and pSV-HSVtk groups. In addition, higher levels of HSVtk gene expression and TUNEL-positive cells were observed in the pEpo-NI2-SV-HSVtk group compared with the control and pSV-HSVtk groups, suggesting that pEpo-NI2-SV-HSVtk increased the therapeutic efficacy in hypoxic glioblastoma. Therefore, pEpo-NI2-SV-HSVtk/PEI-Dexa complex may be useful for glioblastoma-specific gene therapy.

Topics: Animals; Apoptosis; Blotting, Western; Cell Proliferation; Cells, Cultured; Dexamethasone; Drug Carriers; Electrophoretic Mobility Shift Assay; Enhancer Elements, Genetic; Epoetin Alfa; Erythropoietin; Flow Cytometry; Gene Transfer Techniques; Genes, Transgenic, Suicide; Glioblastoma; HEK293 Cells; Humans; Hypoxia; Immunoenzyme Techniques; Introns; Luciferases; Male; Mice; Mice, Inbred BALB C; Mice, Nude; Nestin; Plasmids; Polyethyleneimine; Promoter Regions, Genetic; Rats; Rats, Sprague-Dawley; Recombinant Proteins; Thymidine Kinase; Tissue Distribution; Transfection; Xenograft Model Antitumor Assays

Topics: Animals; Brain Neoplasms; Cell Hypoxia; Cell Line, Tumor; Cell Proliferation; Cell Survival; Enhancer Elements, Genetic; Erythropoietin; Ganciclovir; Gene Expression Regulation; Genes, Reporter; Genes, Transgenic, Suicide; Genetic Therapy; Genetic Vectors; Glioblastoma; Intermediate Filament Proteins; Introns; Luciferases; Nerve Tissue Proteins; Nestin; Neuroglia; Promoter Regions, Genetic; Rats; Simian virus 40; Simplexvirus; Thymidine Kinase; Transfection; Viral Proteins

Erythropoietin (EPO) is a glycoprotein hormone that is a primary regulator of erythropoiesis. In erythroid cells, EPO binds to its receptor (EPOR) to stimulate growth, prevent apoptosis, and promote differentiation. Both EPO and EPOR have been found in many normal and tumor nonerythroid cell types. EPO has been reported to stimulate proliferation and inhibit apoptosis of cancer cells. In this study, we found that EPOR is expressed in brain tumors, glioma cell lines and explants, as well as, normal brain. EPO slightly stimulated the growth of serum-starved glioma cells. Furthermore, EPO increased the phosphorylation of AKT through the PI3K pathway in the glioma cells. It also increased the phosphorylation of ERK, c-jun, JNK, as well as, the expression of BCL-2 and BCL-xl in these cells. These results suggest that the EPO-EPOR pathway may promote glioma cell survival and could become a therapeutic target in brain tumors.

Topics: Apoptosis; Brain Neoplasms; Cell Line, Tumor; Erythropoietin; Glioblastoma; Humans; Phosphorylation; Proto-Oncogene Proteins c-akt; Receptors, Erythropoietin; Signal Transduction

Pronounced oxygen deficiency in tumors which might be caused by a diminished oxygen transport capacity of the blood (e.g., in anemia) reduces the efficacy of ionizing radiation. The aim of this study was to analyze whether anemia prevention by recombinant human erythropoietin (rHuEPO) affects the radiosensitivity of human glioblastoma xenografts during fractionated irradiation.. Anemia was induced by total body irradiation (TBI, 2 x 4 Gy) of mice prior to tumor implantation into the subcuts of the hind leg. In one experimental group, the development of anemia was prevented by rHuEPO (750 U/kg s.c.) given three times weekly starting 10 days prior to TBI. 13 days after tumor implantation (tumor volume approx. 40 mm3), fractionated irradiation (4 x 7 Gy, one daily fraction) of the glioblastomas was performed resulting in a growth delay with subsequent regrowth of the tumors.. Compared to nonanemic control animals (hemoglobin concentration cHb = 14.7 g/dl), the growth delay in anemic mice (cHb = 9.9 g/dl) was significantly shorter (49 +/- 5 days vs. 79 +/- 4 days to reach four times the initial tumor volume) upon fractionated radiation. The prevention of anemia by rHuEPO treatment (cHb = 13.3 g/dl) resulted in a significantly prolonged growth delay (61 +/- 5 days) compared to the anemia group, even though the growth inhibition found in control animals was not completely achieved.. These data indicate that moderate anemia significantly reduces the efficacy of radiotherapy. Prevention of anemia with rHuEPO partially restores the radiosensitivity of xenografted glioblastomas to fractionated irradiation.

Topics: Anemia; Animals; Brain; Brain Neoplasms; Cell Hypoxia; Cell Line, Tumor; Dose Fractionation, Radiation; Erythropoietin; Glioblastoma; Humans; Mice; Mice, Nude; Neoplasm Transplantation; Radiation Tolerance; Radiotherapy Dosage; Recombinant Proteins; Time Factors; Transplantation, Heterologous; Whole-Body Irradiation

Hemangioblastomas are highly vascular tumors of the central nervous system that overexpress the hypoxia-inducible gene, vascular endothelial growth factor (VEGF), as a consequence of mutational inactivation of the von Hippel-Lindau tumor suppressor gene (VHL). Previous reports showed that hemangioblastomas can also express erythropoietin (Epo), which is also hypoxia-inducible. However, Epo expression in hemangioblastomas was observed only in individual cases, and the analyses were mainly based on indirect determination of erythropoiesis-stimulating activity. Therefore, we analyzed a series of 11 hemangioblastomas for Epo, VEGF, and VHL expression by Northern blot analysis and compared the results with normal brain and glioblastomas. Surprisingly, we observed Epo mRNA expression in all hemangioblastoma specimens analyzed, but in none of four glioblastomas. In contrast, VEGF mRNA was expressed in all hemangioblastomas and all glioblastomas. In situ hybridization revealed neoplastic stromal cells as Epo- and VEGF-producing cells in hemangioblastomas. These results suggest that in the nonhypoxic microenvironment of hemangioblastoma, Epo, similar to VEGF, might be negatively regulated by the VHL gene product.

Topics: Adult; Aged; Brain; Brain Neoplasms; Cell Hypoxia; Central Nervous System Neoplasms; Endothelial Growth Factors; Erythropoiesis; Erythropoietin; Female; Gene Expression Regulation, Neoplastic; Genes, Tumor Suppressor; Glioblastoma; Hemangioblastoma; Hormones, Ectopic; Humans; In Situ Hybridization; Ligases; Lymphokines; Male; Middle Aged; Neoplasm Proteins; Nerve Tissue Proteins; Protein Biosynthesis; Proteins; RNA, Messenger; Stromal Cells; Tumor Suppressor Proteins; Ubiquitin-Protein Ligases; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors; von Hippel-Lindau Disease; Von Hippel-Lindau Tumor Suppressor Protein