We measured intracellular accumulation of N-desmethyl imatinib (CGP 74588), the main pharmacologically active metabolite of imatinib (Gleevec or STI-571), in Bcr--Abl-positive cells. Using a sensitive and robust non-radioactive in vitro assay, we observed that CGP74588 accumulates in significantly higher amount than imatinib in sensitive K562 cells. In contrast, the intracellular level of CGP74588 was significantly lower than that of imatinib in K562/Dox cells, which represent a multidrug-resistant variant of K562 cells due to the P-glycoprotein (P-gp, ABCB1, MDR1) overexpression. An in vitro enzyme-based assay provided evidence that CGP74588 might serve as an excellent substrate for P-gp. Accordingly, we found that CGP74588 up to 20 μM concentration neither induced apoptosis nor inhibited substantially cell proliferation in resistant K562/Dox cells. In contrast, CGP74588 was capable to inhibit cell proliferation and induced apoptosis in sensitive K562 cells, although its effect was approximately three to four times lower than that of imatinib in the same cell line. Our results indicate that CGP74588 could hardly positively contribute to the treatment of chronic myeloid leukemia (CML) where ABCB1 gene overexpression represents a possible mechanism of resistance to imatinib in vivo.

• MeSH
• antitumorózní látky * metabolismus   farmakologie   terapeutické užití   MeSH
• apoptóza účinky léků   MeSH
• benzamidy MeSH
• buňky K562 * účinky léků   metabolismus   MeSH
• chronická myeloidní leukemie farmakoterapie   metabolismus   patofyziologie   MeSH
• dospělí MeSH
• imatinib mesylát MeSH
• lidé středního věku MeSH
• lidé MeSH
• P-glykoprotein metabolismus   MeSH
• piperaziny metabolismus   farmakologie   terapeutické užití   MeSH
• proliferace buněk účinky léků   MeSH
• pyrimidiny metabolismus   farmakologie   terapeutické užití   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• výsledek terapie MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• klinické zkoušky MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antitumorózní látky * MeSH
• benzamidy MeSH
• CGP 74588 MeSH Prohlížeč
• imatinib mesylát MeSH
• P-glykoprotein MeSH
• piperaziny MeSH
• pyrimidiny MeSH

BACKGROUND: MicroRNAs are important regulators of transcription in hematopoiesis. Their expression deregulations were described in association with pathogenesis of some hematological malignancies. This study provides integrated microRNA expression profiling at different phases of chronic myeloid leukemia (CML) with the aim to identify microRNAs associated with CML pathogenesis. The functions of in silico filtered targets are in this report annotated and discussed in relation to CML pathogenesis. RESULTS: Using microarrays we identified differential expression profiles of 49 miRNAs in CML patients at diagnosis, in hematological relapse, therapy failure, blast crisis and major molecular response. The expression deregulation of miR-150, miR-20a, miR-17, miR-19a, miR-103, miR-144, miR-155, miR-181a, miR-221 and miR-222 in CML was confirmed by real-time quantitative PCR. In silico analyses identified targeted genes of these miRNAs encoding proteins that are involved in cell cycle and growth regulation as well as several key signaling pathways such as of mitogen activated kinase-like protein (MAPK), epidermal growth factor receptor (EGFR, ERBB), transforming growth factor beta (TGFB1) and tumor protein p53 that are all related to CML. Decreased levels of miR-150 were detected in patients at diagnosis, in blast crisis and 67% of hematological relapses and showed significant negative correlation with miR-150 proved target MYB and with BCR-ABL transcript level. CONCLUSIONS: This study uncovers microRNAs that are potentially involved in CML and the annotated functions of in silico filtered targets of selected miRNAs outline mechanisms whereby microRNAs may be involved in CML pathogenesis.

• MeSH
• anotace sekvence MeSH
• chronická myeloidní leukemie genetika   patofyziologie   MeSH
• down regulace genetika   MeSH
• geny myb genetika   MeSH
• lidé MeSH
• mikro RNA genetika   metabolismus   MeSH
• regulace genové exprese u leukemie * MeSH
• reprodukovatelnost výsledků MeSH
• shluková analýza MeSH
• stanovení celkové genové exprese MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• mikro RNA MeSH
• MIRN150 microRNA, human MeSH Prohlížeč

Chronic myelogenous leukemia (CML) is a hematological malignancy that is characteristic by as expansion of myeloid cells and their premature release into the circulation. The molecular cause of CML is the fusion oncoprotein Bcr-Abl whose constitutive tyrosine-kinase (TK) activity maintains enhanced signaling through multiple signal transduction pathways and confers proliferative and survival advantage to CML cells. These effects can be largely suppressed by TK inhibitor Imatinib mesylate, currently the leading drug in CML treatment. However, Bcr-Abl contains also additional functional domains, in particular a DBL homology (DH) domain with guanine-exchange function (GEF) which can activate small GTPases of Rho family and a Src-homology3 (SH3) domain which recruits other proteins with GEF activity. Bcr-Abl affects among others the RhoA/ROCK/LIM/cofilin pathway that regulates the actin cytoskeleton assembly and thereby the cellular adhesion and migration. This review deals in detail with the known points of interference between Bcr-Abl and Rho kinase pathways and with the effects of Imatinib mesylate on Rho signaling and cell adhesion to the extracellular matrix (ECM) components. The potential protein targets related to Bcr-Abl non-kinase activity are discussed.

• MeSH
• antitumorózní látky farmakologie   MeSH
• bcr-abl fúzové proteiny účinky léků   metabolismus   MeSH
• benzamidy MeSH
• buněčná adheze účinky léků   MeSH
• chronická myeloidní leukemie farmakoterapie   patofyziologie   MeSH
• imatinib mesylát MeSH
• kinázy asociované s rho účinky léků   metabolismus   MeSH
• lidé MeSH
• piperaziny farmakologie   MeSH
• pyrimidiny farmakologie   MeSH
• rho proteiny vázající GTP metabolismus   MeSH
• signální transdukce účinky léků   MeSH
• src homologní domény MeSH
• systémy cílené aplikace léků MeSH
• výměnné faktory guaninnukleotidů metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• antitumorózní látky MeSH
• bcr-abl fúzové proteiny MeSH
• benzamidy MeSH
• imatinib mesylát MeSH
• kinázy asociované s rho MeSH
• piperaziny MeSH
• pyrimidiny MeSH
• rho proteiny vázající GTP MeSH
• výměnné faktory guaninnukleotidů MeSH

Previously, we showed that expression of myeloma-associated (proto)oncogene fibroblast growth factor receptor 3 (FGFR-3) is increased in white blood cells from patients with chronic myeloid leukemia (CML). The abnormal expression was returned back to the normal levels as soon as these patients reconstituted their hematopoiesis following transplantation of allogeneic peripheral blood stem cells. The aims of this study were: (1) to define population(s) of cells overexpressing FGFR-3, and (2) to determine the expression of FGFR-3 during the clinical course of the disease. We show that the vast majority of FGFR-3 transcripts as well as FGFR-3 protein arise from CD34+ BCR-ABL+ cells. Although increased levels of FGFR-3 were found in majority of late chronic phase patients treated with interferon alpha or hydroxyurea, the expression of FGFR-3 was always lowered following treatment with BCR-ABL tyrosine kinase inhibitor STI571. Compared to unstimulated cells, high levels of FGFR-3 were also identified in CD34+ cells from granulocyte colony-stimulating factor-mobilized blood stem cell harvests from healthy donors, suggesting a potential growth factor-dependent basis for elevated expression of FGFR-3 in CML. These findings have implications for the involvement of FGFR-3 in malignant hematopoiesis and depict FGFR-3 tyrosine kinase in CD34+ leukemic cells as a possible target for tyrosine kinase inhibitors.

• MeSH
• antigeny CD34 analýza   MeSH
• bcr-abl fúzové proteiny genetika   MeSH
• buněčná diferenciace MeSH
• buněčné dělení MeSH
• chronická myeloidní leukemie genetika   patologie   patofyziologie   MeSH
• faktor stimulující kolonie granulocytů farmakologie   MeSH
• hematopoetické kmenové buňky chemie   cytologie   MeSH
• hematopoéza MeSH
• lidé MeSH
• protoonkogen Mas MeSH
• průtoková cytometrie MeSH
• receptor fibroblastových růstových faktorů, typ 3 MeSH
• receptory fibroblastových růstových faktorů genetika   MeSH
• regulace genové exprese u leukemie účinky léků   MeSH
• transplantace hematopoetických kmenových buněk MeSH
• tyrosinkinasy * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antigeny CD34 MeSH
• bcr-abl fúzové proteiny MeSH
• faktor stimulující kolonie granulocytů MeSH
• FGFR3 protein, human MeSH Prohlížeč
• MAS1 protein, human MeSH Prohlížeč
• protoonkogen Mas MeSH
• receptor fibroblastových růstových faktorů, typ 3 MeSH
• receptory fibroblastových růstových faktorů MeSH
• tyrosinkinasy * MeSH

• MeSH
• buněčné dělení * MeSH
• chronická myeloidní leukemie patofyziologie   MeSH
• dítě MeSH
• hematopoéza MeSH
• kostní dřeň patofyziologie   MeSH
• lidé MeSH
• nádory patofyziologie   MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH