Chemoresistance is a major problem in successful cancer therapy. Lysine-specific demethylase 5B (KDM5B), is a member of the KDM5 family of histone demethylases, whose dysregulation has been observed in numerous types of cancer and plays a role in drug tolerance. The present study examined KDM5B expression in high risk neuroblastoma cell lines. Its level was markedly reduced in cisplatin-resistant cells, UKF-NB-4CDDP, compared with parental sensitive cells UKF-NB-4. Moreover, KDM5B-silencing did not affect either viability nor the response to CDDP in resistant cells, and led to increase of proliferation and migration in CDDP resistant cells but not in sensitive ones. Compliant with these results, short interfering KDM5B transfection resulted in increased S phase in resistant cells. Overall, these findings suggested that KDM5B may be involved in the survival mechanisms of neuroblastoma cells, which makes KDM5B a promising factor for the prediction of sensitivity to CDDP that should therefore be considered for future research.

• Klíčová slova
• chemoresistance, cisplatin, histone methylation, lysine-specific demethylase 5B, neuroblastoma,
• Publikační typ
• časopisecké články MeSH

Metallothionein-3 has poorly characterized functions in neuroblastoma. Cisplatin-based chemotherapy is a major regimen to treat neuroblastoma, but its clinical efficacy is limited by chemoresistance. We investigated the impact of human metallothionein-3 (hMT3) up-regulation in neuroblastoma cells and the mechanisms underlying the cisplatin-resistance. We confirmed the cisplatin-metallothionein complex formation using mass spectrometry. Overexpression of hMT3 decreased the sensitivity of neuroblastoma UKF-NB-4 cells to cisplatin. We report, for the first time, cisplatin-sensitive human UKF-NB-4 cells remodelled into cisplatin-resistant cells via high and constitutive hMT3 expression in an in vivo model using chick chorioallantoic membrane assay. Comparative proteomic analysis demonstrated that several biological pathways related to apoptosis, transport, proteasome, and cellular stress were involved in cisplatin-resistance in hMT3 overexpressing UKF-NB-4 cells. Overall, our data confirmed that up-regulation of hMT3 positively correlated with increased cisplatin-chemoresistance in neuroblastoma, and a high level of hMT3 could be one of the causes of frequent tumour relapses.

• MeSH
• chemorezistence účinky léků   genetika   MeSH
• cisplatina farmakologie   MeSH
• kuřecí embryo MeSH
• lidé MeSH
• metalothionein 3 biosyntéza   genetika   MeSH
• nádorové buněčné linie MeSH
• nádorové proteiny biosyntéza   genetika   MeSH
• regulace genové exprese u nádorů účinky léků   MeSH
• zvířata MeSH
• Check Tag
• kuřecí embryo MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• cisplatina MeSH
• metalothionein 3 MeSH
• nádorové proteiny MeSH

Pheochromocytomas (PCCs) are rare tumors among children and adolescents and therefore are not genetically well characterized. The most frequently observed chromosomal changes in PCC are losses of 1p, 3q and/or 3p, 6q, 17p, 11q, 22q, and gains of 9q and 17q. Aberrations involving chromosome 11 are more common in malignant tumors. Unfortunately information about gene aberrations in childhood PCC's is limited. We used comparative genomic hybridization (CGH) and array comparative genomic hybridization (aCGH) to screen for copy number changes in four children suffering from pheochromocytoma or paraganglioma. Patients were diagnosed at the age 13 or 14 years. Bilateral pheochromocytoma was associated with von Hippel-Lindau syndrome (VHL). Multiple paraganglioma was associated with a germline mutation in SDHB. We found very good concordance between the results of CGH and aCGH techniques. Losses were observed more frequently than gains. All cases had a loss of chromosome 11 or 11p. Other aberrations were loss of chromosome 3 and 11 in sporadic pheochromocytoma, and loss of 3p and 11p in pheochromocytoma, which carried the VHL mutation. The deletion of chromosome 1p and other changes were observed in paragangliomas. We conclude that both array CGH and CGH analysis identified similar chromosomal regions involved in tumorigenesis of pheochromocytoma and paragangliomas, but we found 3 discrepancies between the methods. We didn't find any, of the proposed, molecular markers of malignancy in our benign cases and therefore we speculate that molecular cytogenetic examination may be helpful in separating benign and malignant forms in the future.

• MeSH
• chromozomální aberace MeSH
• cytogenetika MeSH
• feochromocytom genetika   MeSH
• lidé MeSH
• mladiství MeSH
• nádory nadledvin genetika   MeSH
• paragangliom genetika   MeSH
• srovnávací genomová hybridizace metody   MeSH
• von Hippelova-Lindauova nemoc genetika   MeSH
• zárodečné mutace MeSH
• Check Tag
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• práce podpořená grantem MeSH

Neuroblastoma, a tumor of the peripheral sympathetic nervous system, is the most frequent solid extra cranial tumor in children and is a major cause of death from neoplasia in infancy. Still little improvement in therapeutic options has been made, requiring a need for the development of new therapies. In our laboratory, we address still unsettled questions, which of mechanisms of action of DNA-damaging drugs both currently use for treatment of human neuroblastomas (doxorubicin, cis-platin, cyclophosphamide and etoposide) and another anticancer agent decreasing growth of neuroblastomas in vitro, ellipticine, are predominant mechanism(s) responsible for their antitumor action in neuroblastoma cell lines in vitro. Because hypoxia frequently occurs in tumors and strongly correlates with advanced disease and poor outcome caused by chemoresistance, the effects of hypoxia on efficiencies and mechanisms of actions of these drugs in neuroblastomas are also investigated. Since the epigenetic structure of DNA and its lesions play a role in the origin of human neuroblastomas, pharmaceutical manipulation of the epigenome may offer other treatment options also for neuroblastomas. Therefore, the effects of histone deacetylase inhibitors on growth of neuroblastoma and combination of these compounds with doxorubicin, cis-platin, etoposide and ellipticine as well as mechanisms of such effects in human neuroblastona cell lines in vitro are also investigated. Such a study will increase our knowledge to explain the proper function of these drugs on the molecular level, which should be utilized for the development of new therapies for neuroblastomas.

• Klíčová slova
• DNA-damaging anticancer drugs, inhibitors of histone deacetylases, mechanisms of acticancer effects of drugs, neuroblastoma,
• Publikační typ
• časopisecké články MeSH

Ellipticine is an antineoplastic agent, whose mode of action is based mainly on DNA intercalation, inhibition of topoisomerase II and formation of covalent DNA adducts mediated by cytochromes P450 and peroxidases. Here, the cytotoxicity of ellipticine to human neuroblastoma derived cell lines IMR-32 and UKF-NB-4 was investigated. Treatment of neuroblastoma cells with ellipticine was compared with that of these cancer cells with doxorubicin. The toxicity of ellipticine was essentially the same as that of doxorubicin to UKF-NB-4 cells, but doxorubicin is much more effective to inhibit the growth of the IMR-32 cell line than ellipticine. Hypoxic conditions used for the cell cultivation resulted in a decrease in ellipticine and/or doxorubicin toxicity to IMR-32 and UKF-NB-4 neuroblastoma cells.

• Klíčová slova
• anticancer drug, cytotoxicity, doxorubicin, ellipticine, human neuroblastoma cells,
• Publikační typ
• časopisecké články MeSH