[show abstract][hide abstract] ABSTRACT: Teratomas are very rare intracranial tumors and cytogenetic information on this group remains rare. We report a case of a mature teratoma with abnormal +21 trisomy in tumor karyotype ocurring in a non-Down syndrome (DS) infant. Additionally, the evidence for the contribution of chromosome 21 trisomy in this neoplasia are briefly reviewed. The 6-month-old male baby presented with a posterior fossa tumor. Histological evaluation of tumor specimen showed a mature teratoma composed of fully differentiated ectodermal, mesodermal and endodermal components. Although somatic karyotyping of the index case was normal, composite tumor karyotype depicted 47, XY, +21/46,XY. Besides previous reports of children with DS and intracranial teratomas, this is the first report to describe the occurrence of an isolated chromosome 21 trisomy within the tumor of a non-DS child. The participation of chromosome 21 in this rare pediatric tumor, either somatic or restricted to tumor specimen, may deserve special interest and further investigation.
[show abstract][hide abstract] ABSTRACT: Abstract Cellular hypoxic condition is a key event in several human cancers but the knowledge about its role in childhood ALL is very limited. In the present study gene expression profile of hypoxia-related genes (HIF1A, CA9, VEGF and SCL2A1) was evaluated in bone marrow samples of 113 pediatric patients. HIF1A mRNA up-regulation was significantly associated with higher 5-years event-free survival rates in B-ALL patients as well as in the overall ALL population in both univariate and multivariate analysis (P = 0.023 and P = 0.041 respectively). In gene expression analysis, low oxygen levels promoted HIF1A activation in a time-dependent manner, in both ALL cell lines. In vitro cytotoxic assays suggested an initial trend to hypoxia-related resistance in the first 24 hours, but later time points (48 - 72 hours) evaluation clearly showed that there is no relevant difference in drug response when comparing hypoxic to normal oxygen level conditions. Modulation of mRNA expression of several hypoxia-related genes was also observed after hypoxic exposure in a cell specific manner, suggesting that HIF1A mRNA expression could play a different role in specific subtypes of leukemia. Despite the remaining questions regarding hypoxia-mediated mechanisms, these findings could be helpful to provide new insights in the role of hypoxia in childhood ALL.
[show abstract][hide abstract] ABSTRACT: Mowat-Wilson syndrome (MWS) is a rare genetic condition where variable and multiple congenital anomalies including Hirschsprung's disease, intellectual disability, and prominent facial features are present. At molecular level, MWS is characterized by many different described mutations in the zinc finger E-box protein 2 (ZEB2) gene, ultimately leading to loss of gene function. This report is the first to describe the association of MWS with two different asynchronous malignant brain tumors (medulloblastoma and glioblastoma) occurring in a child.
Child s Nervous System 10/2013; · 1.24 Impact Factor
[show abstract][hide abstract] ABSTRACT: Acute lymphoblastic leukemia (ALL) is the most common hematologic malignancy in childhood. Despite the advances in treatment, about 20% of patients relapse and/or die, indicating the need for different therapies for this group. Zebularine (ZB) is a potent DNA methyltransferase (DNMT) inhibitor and has been associated with gene demethylation and enhancement of tumor chemosensitivity. This study aimed to evaluate the effects of ZB, alone or combined with chemotherapeutics (methotrexate and vincristine), on childhood ALL cell lines. Cell proliferation, apoptosis, and clonogenic capacity were studied in Jurkat and ReH cell lines. Bisulfite modification, followed by methylation-specific PCR was carried out to evaluate aryl hydrocarbon receptor (AhR) methylation status. Gene expression of DNMT1, DNMT3a, DNMT3b, and AhR was assessed using qRT-PCR. Both cell cultures were sensitive to ZB, showing a dose-dependent and time-dependent response (P<0.05). ZB induced apoptosis and decreased clonogenic capacity in both cell lines. Combination with methotrexate resulted in a strong synergistic effect, whereas combination with vincristine led to an antagonistic response in both cell lines. ZB treatment decreased gene expression of the three DNMTs and induced AhR gene promoter demethylation and its re-expression. These results indicate that ZB may be a promising drug for the adjuvant treatment of ALL, mainly when combined with methotrexate.
[show abstract][hide abstract] ABSTRACT: Glioblastoma (GBM) is one of the most aggressive central nervous system tumors with a patient's median survival of <1 year. Polo-like kinases (PLKs) are a family of serine/threonine kinases that have key roles in cell cycle control and DNA-damage response. We evaluated PLK1, 2, 3 and 4 gene expression in 8 GBM cell lines and 17 tumor samples, and analyzed the effect of the PLK1 inhibition on SF188 and T98G GBM cell lines and 13 primary cultures. Our data showed PLK1 overexpression and a variable altered expression of PLK2, 3 and 4 genes in GBM tumor samples and cell lines. Treatments with nanomolar concentrations of BI 2536, BI 6727, GW843682X or GSK461364 caused a significant decrease in GBM cells proliferation. Colony formation was also found to be inhibited (P<0.05), whereas apoptosis rate and mitotic index were significantly increased (P<0.05) after PLK1 inhibition in both GBM cell lines. Cell cycle analysis showed an arrest at G2 (P<0.05) and cell invasion was also decreased after PLK1 inhibition. Furthermore, simultaneous combinations of BI 2536 and temozolomide produced synergistic effects for both the cell lines after 48 h of treatment. Our findings suggest that PLK1 might be a promising target for the treatment of GBMs.Cancer Gene Therapy advance online publication, 26 July 2013; doi:10.1038/cgt.2013.46.
[show abstract][hide abstract] ABSTRACT: PURPOSE: Glioblastoma (GBM) is a very aggressive and lethal brain tumor with poor prognosis. Despite new treatment strategies, patients' median survival is still lower than 1 year in most cases. The expression of the BUB gene family has demonstrated to be altered in a variety of solid tumors, pointing to a role as putative therapeutic target. The purpose of this study was to determine BUB1, BUB3, and BUBR1 gene expression profiles in glioblastoma and to analyze the effects of BUB1 and BUBR1 inhibition combined or not with Temozolomide and radiation in the pediatric SF188 GBM cell line. METHODS: For gene expression analysis, 8 cell lines and 18 tumor samples were used. The effect of BUB1 and BUBR1 inhibition was evaluated using siRNA. Apoptosis, cell proliferation, cell cycle kinetics, micronuclei formation, and clonogenic capacity were analyzed after BUB1 and BUBR1 inhibition. Additionally, combinatorial effects of gene inhibition and radiation or Temozolomide (TMZ) treatment were evaluated through proliferation and clonogenic capacity assays. RESULTS: We report the upregulation of BUB1 and BUBR1 expression and the downregulation of BUB3 in GBM samples and cell lines when compared to white matter samples (p < 0.05). Decreased cell proliferation and colony formation after BUB1 and BUBR1 inhibition were observed, along with increased micronuclei formation. Combinations with TMZ also caused cell cycle arrest and increased apoptosis. Moreover, our results demonstrate that BUB1 and BUBR1 inhibition sensitized SF188 cells to γ-irradiation as shown by decreased growth and abrogation of colony formation capacity. CONCLUSION: BUB1 and BUBR1 inhibition decreases proliferation and shows radiosensitizing effects on pediatric GBM cells, which could improve treatment strategies for this devastating tumor. Collectively, these findings highlight the potentials of BUB1 and BUBR1 as putative therapeutic targets for glioblastoma treatment.
Child s Nervous System 06/2013; · 1.24 Impact Factor
[show abstract][hide abstract] ABSTRACT: Despite the improvements in neoadjuvant chemotherapy, the outcome of patients with advanced bladder cancer has changed very little over the past 30 y. In the present study we tested and compared the in vitro antitumor activities of four different inhibitors of Polo-like kinase 1 (PLK1) (BI 2536, BI 6727, GW843682X and GSK461364), against three bladder carcinoma cell lines RT4, 5637 and T24. The impact on radiosensitivity and drug interactions in simultaneous treatments with cisplatin, methotrexate and doxorrubicin were also investigated. Our results showed that PLK1 inhibition prevented cell proliferation and clonogenicity, causing significant inhibition of invasion of tumor cells, though modest differences were observed between drugs. Moreover, all PLK1 inhibitors induced G 2/M arrest, with the subsequent induction of death in all three cell lines. Drug interactions studies showed auspicious results for all PLK1 inhibitors when combined with the commonly used cisplatin and methotrexate, though combinations with doxorubicin showed mostly antagonistic effects. Comparably, the four PLK1 inhibitors efficiently sensitized cells to ionizing radiation. Our findings demonstrate that irrespective of the inhibitor used, the pharmacological inhibition of PLK1 constrains bladder cancer growth and dissemination, providing new opportunities for future therapeutic intervention. However, further laboratorial and pre-clinical tests are still needed to corroborate the usefulness of using them in combination with other commonly used chemotherapeutic drugs.
Cancer biology & therapy 05/2013; 14(7). · 3.29 Impact Factor
[show abstract][hide abstract] ABSTRACT: Abstract Despite efforts to improve surgical, radiologic, and chemotherapeutic strategies, the outcome of patients with glioblastoma (GBM) is still poor. Polo-like kinase 1 (PLK1) is a serine/threonine kinase that plays key roles in cell cycle control and has been associated with tumor growth and prognosis. Here, we aimed at testing the radiosensitizing effects of the PLK1 inhibitor BI 2536 on eight GBM cell lines. For cell cycle analysis, T98G, U251, U343 MG-a, LN319, SF188, U138 MG, and U87 MG cell lines were treated with 10, 50, or 100 nM of BI 2536 for 24 hours. In addition, cell cultures exposed to BI 2536 50 nM for 24 hours were irradiated with γ-rays from (60)Cobalt source at final doses of 2, 4, and 6 Gy. Combinatorial effects were evaluated through proliferation and clonogenic capacity assays. Treatment with BI 2536 caused mitotic arrest after 24 hours, and increased apoptosis in GBM cells. Moreover, our results demonstrate that pretreatment with this drug sensitized six out of seven GBM cell lines to different doses of γ-irradiation as shown by decreased growth and abrogation of colony-formation capacity. Our data suggest that PLK1 blockage has a radiosensitizing effect on GBM, which could improve treatment strategies for this devastating tumor.
Cancer Biotherapy & Radiopharmaceuticals 05/2013; · 1.44 Impact Factor
[show abstract][hide abstract] ABSTRACT: Both dyskeratosis congenita (DC) and Hoyeraal-Hreidarsson Syndrome (HHS) are rare inherited bone marrow failure conditions. HHS is considered to be a variant of DC in which neurological deficits and immunodeficiencies are also present. We describe a very interesting familial cluster where an invariant point mutation of DKC1 located in the exon 11 is observed in the carrier mother and in two decedent males. The older child developed the classical phenotype of HHS at a very early age. The second affected child remains poorly symptomatic, with only mild haematological changes. Telomere shortening, with different severity, is also present in both cases. This paper discusses the clinical spectrum of inherited BM failure syndromes from the perspective different clinical presentation within a family with a DKC1 mutation.
[show abstract][hide abstract] ABSTRACT: Abstract Osteosarcoma (OS) is the most common primary malignant bone tumor. Despite advances in neoadjuvant multi-agent chemotherapy, the outcome of patients has not significantly improved in the last decades, making the search for more effective therapeutic agents imperative. In the present study, we explored the possibility of using activator protein-1 inhibition by 3-[(dodecylthiocarbonyl)methyl]-glutarimide (DTCM-g) as a new therapeutic strategy in two OS cell lines, HOS and MG-63. Our results showed that low concentrations (2.5, 5, 10, and 20 μg/mL) of the drug significantly decreased cell proliferation and clonogenic capacity, albeit it did not significantly induce cell death. DTCM-g also decreased cell invasiveness, and inhibited PDPN, MMP-2, TIMP1, and TIMP2 expressions. Moreover, our results showed that DTCM-g synergized with ionizing radiation in both cell lines while chemosensitized MG-63 cells to doxorubicin treatment. Even though additional laboratorial and preclinical tests are still needed to support our data, we demonstrate that DTCM-g inhibits growth in OS cells, increases the cytotoxicity of other commonly used agents, and may possess antimetastatic activity.
Cancer Biotherapy & Radiopharmaceuticals 01/2013; · 1.44 Impact Factor
[show abstract][hide abstract] ABSTRACT: Chromosomal heterogeneity is a hallmark of most tumors and it can drive critical events as growth advantages, survival advantages, progression and karyotypic evolution. Medulloblastoma (MB) is the most common malignant central nervous system tumor in children. This work attempted to investigate chromosomal heterogeneity and instability profiles of two MB pediatric cell lines and their relationship with cell phenotype. We performed GTG-banding and cytokinesis-block micronucleus cytome assays, as well as morphological characterization, cell population doubling time, colony-forming efficiency, and chemo-sensitivity assays in two pediatric MB cell lines (UW402 and UW473). Both MB cells showed a high chromosomal heterogeneity. UW473 cells showed ~2 fold higher both clonal- and non-clonal chromosomal alterations than UW402 cells. Besides, UW473 showed two clonal-groups well-differentiated by ploidy level (<2n> and <4n>) and also presented a significantly higher number of chromosomal instability biomarkers. These results were associated with high morphological heterogeneity and survival advantages for UW473 and proliferation advantages for UW402 cells. Moreover, UW473 was significantly more sensitive to methotrexate, temozolomide and cisplatin while UW402 cells were more sensitive to doxorubicin. These data suggest that distinct different degrees of karyotypic heterogeneity and instability may affect neoplasic phenotype of MB cells. These findings bring new insights into cell and tumor biology.
[show abstract][hide abstract] ABSTRACT: Glioblastoma (GBM), one of the most malignant human neoplasias, responds poorly to current treatment modalities, with temozolomide (TMZ) being the drug most frequently used for its treatment. Tetra-O-methyl Nordihydroguaiaretic Acid (M4N) is a global transcriptional repressor of genes dependent on the Sp1 transcription factor, such as Survivin and Cdk1. In the present study we evaluated the gene expression of Survivin, its spliced variants and Cdk1 in GBM samples and cell lines. Moreover, we investigated the effects of M4N combined or not with TMZ and/or radiation on GBM primary cultures and cell lines. qRT-PCR assays were performed to determine the Survivin-spliced variants and Cdk1 gene mRNA expression in GBM tumor samples and cell lines. Cell proliferation was measured by XTT assay and cell cycle and apoptosis were determined by flow cytometry. Drug combination analyses using different schedules of administration (simultaneous and sequential) were performed on GBM cell lines and primary cultures based on the Chou-Talalay method. For clonogenic survival, doses of 2, 4, and 6 Gy of gamma radiation. were used. All Survivin-spliced variants and the Cdk1 gene were expressed in GBM samples (n = 16) and cell lines (n = 6), except the Survivin-2B variant that was only expressed in GBM cell lines. M4N treatment down regulated the expression of Cdk1, Survivin and the Survivin-ΔEx3 variant, while the Survivin-2B variant was up-regulated. M4N decreased the cell proliferation separately and synergistically with TMZ, and enhanced the effects of radiation, mainly when associated with TMZ. M4N also induced apoptotic cell death, decreased the mitotic index and arrested the cell cycle mainly in the G2/M phase. Our results suggest a potential clinical application of M4N in combination with TMZ and radiation for GB treatment.
Investigational New Drugs 01/2013; · 3.50 Impact Factor
[show abstract][hide abstract] ABSTRACT: Despite advances in neurosurgery and aggressive treatment with temozolomide (TMZ) and radiation, the overall survival of patients with glioblastoma (GBM) remains poor. Vast evidence has indicated that the nuclear factor NF- κ B is constitutively activated in cancer cells, playing key roles in growth and survival. Recently, Dehydroxymethylepoxyquinomicin (DHMEQ) has shown to be a selective NF- κ B inhibitor with antiproliferative properties in GBM. In the present study, the ability of DHMEQ to surmount tumor's invasive nature and therapy resistance were further explored. Corroborating results showed that DHMEQ impaired cell growth in dose- and time-dependent manners with G2/M arrest when compared with control. Clonogenicity was also significantly diminished with increased apoptosis, though necrotic cell death was also observed at comparable levels. Notably, migration and invasion were inhibited accordingly with lowered expression of invasion-related genes. Moreover, concurrent combination with TMZ synergistically inhibited cell growth in all cell lines, as determined by proliferation and caspase-3 activation assays, though in those that express O(6)-methylguanine-DNA methyltransferase, the synergistic effects were schedule dependent. Pretreatment with DHMEQ equally sensitized cells to ionizing radiation. Taken together, our results strengthen the potential usefulness of DHMEQ in future therapeutic strategies for tumors that do not respond to conventional approaches.
Chemotherapy research and practice. 01/2013; 2013:593020.
[show abstract][hide abstract] ABSTRACT: Ionizing radiation is the most recognized risk factor for meningioma in pediatric long-term cancer survivors. Information in this rare setting is exceptional. We report the clinical and cytogenetic findings in a radiation-induced atypical meningioma following treatment for desmoplastic medulloblastoma in a child. This is the second study to describe the cytogenetic aspects on radiation-induced meningiomas in children. Chromosome banding analysis revealed a 46, XX, t(1;3)(p22;q12), del(1)(p?)/46, XX. Loss of chromosome 1p as a consequence of irradiation has been proposed to be more important in the development of secondary meningiomas in adults. Deletions in the short arm of chromosome 1 also appear to be a shared feature in both pediatric cases so far analyzed.
Journal of Neuro-Oncology 10/2012; · 3.12 Impact Factor
[show abstract][hide abstract] ABSTRACT: The present study evaluated the expression profile of 19 genes previously reported in microarray studies and associated with resistance or sensitivity to vincristine (RPLP2, CD44, TCFL5, KCNN1, TRIM24), prednisolone (F8A, CDK2AP1, BLVRB, CD69), daunorubicin (MAP3K12, SHOC2, PCDH9, EGR1, KCNN4) and l-asparaginase (GPR56, MAN1A1, CLEC11A, IGFBP7, GATA3). We studied 140 bone marrow samples at diagnosis from children with acute lymphoblastic leukemia (ALL) treated according to the Brazilian Childhood Leukemia Treatment Group (GBTLI) ALL-99 protocol. The expression profiles of the genes listed above were analyzed by real-time quantitative polymerase chain reaction (PCR) and then related to the clinical and biological prognostic factors. The results showed significant associations (p ≤ 0.05) between the expression levels of genes GPR56, BLVRB, IGFBP7 and white blood cell (WBC) count at diagnosis; GATA3, MAN1A1, CD44, MAP3K12, CLEC11A, SHOC2 and CD10 B-lineage ALL; TCFL5 and bone marrow status at day 14; MAP3K12 and TRIM24 and bone marrow status at day 28; and CD69, TCFL5 and TRIM24 genes and ETV6/RUNX1 positive ALL. The up-regulation of SHOC2 was also associated with better 5-year event-free survival (EFS) in univariate and multivariate analysis (p = 0.02 and p = 0.03, respectively). These findings highlight genes that could be associated with clinical and biological prognostic factors in childhood ALL, suggesting that these genes may characterize and play a role in the treatment outcome of some ALL subsets.
[show abstract][hide abstract] ABSTRACT: Hypoxia is one of many factors involved in the regulation of the IGF system. However, no information is available regarding the regulation of the IGF system by acute hypoxia in humans. Objective: The aim of this study was to evaluate the effect of acute hypoxia on the IGF system of children. Design: Twenty-seven previously health children (14 boys and 13 girls) aged 15 days to 9.5 years were studied in two different situations: during a hypoxemic state (HS) due to acute respiratory distress and after full recovery to a normoxemic state (NS). In these two situations oxygen saturation was assessed with a pulse-oximeter and blood samples were collected for serum IGF-I, IGF-II, IGFBP-1, IGFBP-3, ALS and insulin determination by ELISA; fluoroimmunometric assay determination for GH and also for IGF1R gene expression analysis in peripheral lymphocytes by quantitative real-time PCR. Data were paired and analyzed by the Wilcoxon non-parametric test. Results: Oxygen saturation was significantly lower during HS than in NS (P<0.0001). IGF-I and IGF-II levels were lower during HS than in NS (P<0.0001 and P=0.0004, respectively). IGFBP-3 levels were also lower in HS than in NS (P=0.0002) while ALS and basal GH levels were higher during HS (P=0.0015 and P=0.014, respectively). Moreover, IGFBP-1 levels were higher during HS than in NS (P=0.004). No difference was found regarding insulin levels. The expression of IGF1R mRNA as 2(-ΔΔCT) was higher during HS than in NS (P=0.03). Conclusion: The above results confirm a role of hypoxia in the regulation of the IGF system also in humans. This effect could be direct on the liver and/or mediated by GH and it is not restricted to the hepatocytes but involves other cell lines. During acute hypoxia a combination of alterations usually associated with reduced IGF action was observed. The higher expression of IGF1R mRNA may reflect an up-regulation of the transcriptional process.
Growth hormone & IGF research: official journal of the Growth Hormone Research Society and the International IGF Research Society 08/2012; 22(5):186-91. · 2.35 Impact Factor