OBJECTIVE: A prominent, safe and efficient therapy for patients with chronic myeloid leukemia (CML) is inhibiting oncogenic protein BCR::ABL1 in a targeted manner with imatinib, a tyrosine kinase inhibitor. A substantial part of patients treated with imatinib report skeletomuscular adverse events affecting their quality of life. OCTN2 membrane transporter is involved in imatinib transportation into the cells. At the same time, the crucial physiological role of OCTN2 is cellular uptake of carnitine which is an essential co-factor for the mitochondrial β-oxidation pathway. This work investigates the impact of imatinib treatment on carnitine intake and energy metabolism of muscle cells. METHODS: HTB-153 (human rhabdomyosarcoma) cell line and KCL-22 (CML cell line) were used to study the impact of imatinib treatment on intracellular levels of carnitine and vice versa. The energy metabolism changes in cells treated by imatinib were quantified and compared to changes in cells exposed to highly specific OCTN2 inhibitor vinorelbine. Mouse models were used to test whether in vitro observations are also achieved in vivo in thigh muscle tissue. The analytes of interest were quantified using a Prominence HPLC system coupled with a tandem mass spectrometer. RESULTS: This work showed that through the carnitine-specific transporter OCTN2, imatinib and carnitine intake competed unequally and intracellular carnitine concentrations were significantly reduced. In contrast, carnitine preincubation did not influence imatinib cell intake or interfere with leukemia cell targeting. Blocking the intracellular supply of carnitine with imatinib significantly reduced the production of most Krebs cycle metabolites and ATP. However, subsequent carnitine supplementation rescued mitochondrial energy production. Due to specific inhibition of OCTN2 activity, the influx of carnitine was blocked and mitochondrial energy metabolism was impaired in muscle cells in vitro and in thigh muscle tissue in a mouse model. CONCLUSIONS: This preclinical experimental study revealed detrimental effect of imatinib on carnitine-mediated energy metabolism of muscle cells providing a possible molecular background of the frequently occurred side effects during imatinib therapy such as fatigue, muscle pain and cramps.
- MeSH
- chronická myeloidní leukemie * farmakoterapie metabolismus MeSH
- energetický metabolismus účinky léků MeSH
- imatinib mesylát * farmakologie škodlivé účinky MeSH
- inhibitory proteinkinas farmakologie škodlivé účinky MeSH
- karnitin * metabolismus farmakologie MeSH
- lidé MeSH
- mitochondrie metabolismus účinky léků MeSH
- myši MeSH
- nádorové buněčné linie MeSH
- protinádorové látky škodlivé účinky farmakologie MeSH
- rodina nosičů rozpuštěných látek 22, člen 5 * metabolismus MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- MeSH
- bcr-abl fúzní proteiny genetika MeSH
- blastická krize * genetika farmakoterapie patologie MeSH
- chronická myeloidní leukemie * farmakoterapie genetika patologie MeSH
- imidazoly * terapeutické užití aplikace a dávkování MeSH
- inhibitory proteinkinas terapeutické užití farmakologie MeSH
- lidé MeSH
- mutace * MeSH
- myši MeSH
- niacinamid analogy a deriváty MeSH
- protokoly protinádorové kombinované chemoterapie terapeutické užití MeSH
- pyrazoly MeSH
- pyridaziny * terapeutické užití aplikace a dávkování MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- dopisy MeSH
The transcription factor PU.1 (Purine-rich DNA binding, SPI1) is a key regulator of hematopoiesis, whose level is influenced by transcription through its enhancers and its post-transcriptional degradation via microRNA-155 (miR-155). The degree of transcriptional regulation of the PU.1 gene is influenced by repression via DNA methylation, as well as other epigenetic factors, such as those related to progenitor maturation status, which is modulated by the transcription factor Myeloblastosis oncogene (MYB). In this work, we show that combinatorial treatment of acute myeloid leukemia (AML) cells with DNA methylation inhibitors (5-Azacytidine), MYB inhibitors (Celastrol), and anti-miR-155 (AM155) ideally leads to overproduction of PU.1. We also show that PU.1 reactivation can be compensated by miR-155 and that only a combined approach leads to sustained PU.1 derepression, even at the protein level. The triple effect on increasing PU.1 levels in myeloblasts stimulates the myeloid transcriptional program while inhibiting cell survival and proliferation, leading to partial leukemic differentiation.
- MeSH
- akutní myeloidní leukemie * farmakoterapie genetika MeSH
- buněčná diferenciace genetika MeSH
- lidé MeSH
- mikro RNA * genetika metabolismus MeSH
- protoonkogenní proteiny genetika metabolismus MeSH
- regulace genové exprese u leukemie MeSH
- trans-aktivátory metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Somatic mutations are a common molecular mechanism through which chronic myeloid leukemia (CML) cells acquire resistance to tyrosine kinase inhibitors (TKIs) therapy. While most of the mutations in the kinase domain of BCR-ABL1 can be successfully managed, the recurrent somatic mutations in other genes may be therapeutically challenging. Despite the major clinical relevance of mutation-associated resistance in CML, the mechanisms underlying mutation acquisition in TKI-treated leukemic cells are not well understood. This work demonstrated de novo acquisition of mutations on isolated single-cell sorted CML clones growing in the presence of imatinib. The acquisition of mutations was associated with the significantly increased expression of the LIG1 and PARP1 genes involved in the error-prone alternative nonhomologous end-joining pathway, leading to genomic instability, and increased expression of the UNG, FEN and POLD3 genes involved in the base-excision repair (long patch) pathway, allowing point mutagenesis. This work showed in vitro and in vivo that de novo acquisition of resistance-associated mutations in oncogenes is the prevalent method of somatic mutation development in CML under TKIs treatment.
- Publikační typ
- časopisecké články MeSH
- MeSH
- azacytidin analogy a deriváty farmakologie terapeutické užití MeSH
- DNA modifikační methylasy genetika metabolismus MeSH
- DNA-(cytosin-5)-methyltransferasa 1 antagonisté a inhibitory MeSH
- epigeneze genetická MeSH
- hematopoetické kmenové buňky MeSH
- lidé MeSH
- metylace DNA * genetika účinky léků MeSH
- mutace genetika MeSH
- myelodysplastické syndromy * farmakoterapie genetika MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
Follicular lymphoma (FL) is a common indolent B-cell malignancy with a variable clinical course. An unfavorable event in its course is histological transformation to a high-grade lymphoma, typically diffuse large B-cell lymphoma. Recent studies show that genetic aberrations of MYC or its overexpression are associated with FL transformation (tFL). However, the precise molecular mechanisms underlying tFL are unclear. Here we performed the first profiling of expression of microRNAs (miRNAs) in paired samples of FL and tFL and identified 5 miRNAs as being differentially expressed. We focused on one of these miRNAs, namely miR-150, which was uniformly downmodulated in all examined tFLs (∼3.5-fold), and observed that high levels of MYC are responsible for repressing miR-150 in tFL by binding in its upstream region. This MYC-mediated repression of miR-150 in B cells is not dependent on LIN28A/B proteins, which influence the maturation of miR-150 precursor (pri-miR-150) in myeloid cells. We also demonstrated that low miR-150 levels in tFL lead to upregulation of its target, namely FOXP1 protein, which is a known positive regulator of cell survival, as well as B-cell receptor and NF-κB signaling in malignant B cells. We revealed that low levels of miR-150 and high levels of its target, FOXP1, are associated with shorter overall survival in FL and suggest that miR-150 could serve as a good biomarker measurable in formalin-fixed paraffin-embedded tissue. Overall, our study demonstrates the role of the MYC/miR-150/FOXP1 axis in malignant B cells as a determinant of FL aggressiveness and its high-grade transformation.
- MeSH
- aktivace transkripce MeSH
- difúzní velkobuněčný B-lymfom genetika patologie MeSH
- down regulace MeSH
- folikulární lymfom diagnóza genetika patologie MeSH
- forkhead transkripční faktory genetika MeSH
- lidé MeSH
- mikro RNA genetika MeSH
- nádorová transformace buněk genetika patologie MeSH
- prognóza MeSH
- protoonkogenní proteiny c-myc genetika MeSH
- regulace genové exprese u nádorů * MeSH
- represorové proteiny genetika MeSH
- upregulace MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The fusion oncoprotein BCR-ABL1 exhibits aberrant tyrosine kinase activity and it has been proposed that it deregulates signaling networks involving both transcription factors and non-coding microRNAs that result in chronic myeloid leukemia (CML). Previously, microRNA expression profiling showed deregulated expression of miR-150 and miR-155 in CML. In this study, we placed these findings into the broader context of the MYC/miR-150/MYB/miR-155/PU.1 oncogenic network. We propose that up-regulated MYC and miR-155 in CD34+ leukemic stem and progenitor cells, in concert with BCR-ABL1, impair the molecular mechanisms of myeloid differentiation associated with low miR-150 and PU.1 levels. We revealed that MYC directly occupied the -11.7 kb and -0.35 kb regulatory regions in the MIR150 gene. MYC occupancy was markedly increased through BCR-ABL1 activity, causing inhibition of MIR150 gene expression in CML CD34+ and CD34- cells. Furthermore, we found an association between reduced miR-150 levels in CML blast cells and their resistance to tyrosine kinase inhibitors (TKIs). Although TKIs successfully disrupted BCR-ABL1 kinase activity in proliferating CML cells, this treatment did not efficiently target quiescent leukemic stem cells. The study presents new evidence regarding the MYC/miR-150/MYB/miR-155/PU.1 leukemic network established by aberrant BCR-ABL1 activity. The key connecting nodes of this network may serve as potential druggable targets to overcome resistance of CML stem and progenitor cells.
- MeSH
- bcr-abl fúzní proteiny genetika MeSH
- buněčná diferenciace účinky léků genetika MeSH
- buňky K562 MeSH
- chemorezistence účinky léků genetika MeSH
- chronická myeloidní leukemie farmakoterapie genetika patologie MeSH
- dospělí MeSH
- down regulace účinky léků MeSH
- geny myc genetika MeSH
- HL-60 buňky MeSH
- inhibitory proteinkinas farmakologie MeSH
- lidé středního věku MeSH
- lidé MeSH
- mikro RNA genetika MeSH
- nádorové buněčné linie MeSH
- nádorové kmenové buňky účinky léků metabolismus MeSH
- proliferace buněk účinky léků genetika MeSH
- regulace genové exprese u leukemie účinky léků MeSH
- senioři MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
