PURPOSE: Pediatric sarcomas are bone and soft tissue tumors that often exhibit high metastatic potential and refractory stem-like phenotypes, resulting in poor outcomes. Aggressive sarcomas frequently harbor a disrupted p53 pathway. However, whether pediatric sarcoma stemness is associated with abrogated p53 function and might be attenuated via p53 reactivation remains unclear. METHODS: We utilized a unique panel of pediatric sarcoma models and tumor tissue cohorts to investigate the correlation between the expression of stemness-related transcription factors, p53 pathway dysregulations, tumorigenicity in vivo, and clinicopathological features. TP53 mutation status was assessed by next-generation sequencing. Major findings were validated via shRNA-mediated silencing and functional assays. The p53 pathway-targeting drugs were used to explore the effects and selectivity of p53 reactivation against sarcoma cells with stem-like traits. RESULTS: We found that highly tumorigenic stem-like sarcoma cells exhibit dysregulated p53, making them vulnerable to drugs that restore wild-type p53 activity. Immunohistochemistry of mouse xenografts and human tumor tissues revealed that p53 dysregulations, together with enhanced expression of the stemness-related transcription factors SOX2 or KLF4, are crucial features in pediatric osteosarcoma, rhabdomyosarcoma, and Ewing's sarcoma development. p53 dysregulation appears to be an important step for sarcoma cells to acquire a fully stem-like phenotype, and p53-positive pediatric sarcomas exhibit a high frequency of early metastasis. Importantly, reactivating p53 signaling via MDM2/MDMX inhibition selectively induces apoptosis in aggressive, stem-like Ewing's sarcoma cells while sparing healthy fibroblasts. CONCLUSIONS: Our results indicate that restoring canonical p53 activity provides a promising strategy for developing improved therapies for pediatric sarcomas with unfavorable stem-like traits.

• Klíčová slova
• Cancer stemness, Pediatric sarcomas, Prognosis, Targeted therapy, p53,
• MeSH
• dítě MeSH
• Krüppel-like faktor 4 * MeSH
• lidé MeSH
• mladiství MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• nádorové kmenové buňky * metabolismus   patologie   MeSH
• nádorový supresorový protein p53 * metabolismus   genetika   MeSH
• předškolní dítě MeSH
• regulace genové exprese u nádorů MeSH
• sarkom * genetika   patologie   metabolismus   MeSH
• signální transdukce MeSH
• xenogenní modely - testy protinádorové aktivity MeSH
• zvířata MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• myši MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• KLF4 protein, human MeSH Prohlížeč
• Klf4 protein, mouse MeSH Prohlížeč
• Krüppel-like faktor 4 * MeSH
• nádorový supresorový protein p53 * MeSH

WW domain binding protein 1-like (WBP1L), also known as outcome predictor of acute leukemia 1 (OPAL1), is a transmembrane adaptor protein, expression of which was shown to correlate with ETV6-RUNX1 translocation and favorable prognosis in childhood leukemia. It has a broad expression pattern in hematopoietic and non-hematopoietic cells. Our previous work described WBP1L as a regulator of CXCR4 signaling and hematopoiesis. Here, we show that hematopoiesis in the mice with Wbp1l germline deletion is dysregulated, already at the level of hematopoietic stem cells and early progenitors. We further demonstrate that thymi of WBP1L-deficient mice are significantly enlarged and contain increased numbers of thymocytes of all subsets. This can potentially be explained by increased generation of multipotent progenitors 4 (MPP4) in the bone marrow, from which the thymus-seeding progenitors are derived. We also observed increases in multiple cell types in the blood. In addition, we show that WBP1L regulates hematopoietic stem cell functionality and leukocyte progenitor proliferation and gene expression during hematopoietic stem and progenitor cell transplantation, which contribute to more efficient engraftment of WBP1L-deficient cells. WBP1L thus emerges as a regulator of hematopoietic stem and progenitor cell function, which controls leukocyte numbers at the steady state and after bone marrow transplantation.

• Klíčová slova
• T cell development, WBP1L, hematopoiesis, hematopoietic stem and progenitor cell transplantation, hematopoietic stem cells, transmembrane adaptor protein,
• MeSH
• hematopoetické kmenové buňky * fyziologie   MeSH
• hematopoéza * MeSH
• membránové proteiny * genetika   metabolismus   MeSH
• myši inbrední C57BL MeSH
• myši knockoutované MeSH
• myši MeSH
• počet leukocytů MeSH
• regulace genové exprese MeSH
• thymocyty fyziologie   MeSH
• thymus * cytologie   fyziologie   MeSH
• transplantace hematopoetických kmenových buněk MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• membránové proteiny * MeSH
• Wbp1l protein, mouse MeSH Prohlížeč

Pegylated interferon alfa (pegIFN-α) can induce molecular remissions in patients with JAK2-V617F-positive myeloproliferative neoplasms (MPNs) by targeting long-term hematopoietic stem cells (LT-HSCs). Additional somatic mutations in genes regulating LT-HSC self-renewal, such as DNMT3A, have been reported to have poorer responses to pegIFN-α. We investigated whether DNMT3A loss leads to alterations in JAK2-V617F LT-HSC functions conferring resistance to pegIFN-α treatment in a mouse model of MPN and in hematopoietic progenitors from patients with MPN. Long-term treatment with pegIFN-α normalized blood parameters and reduced splenomegaly and JAK2-V617F chimerism in single-mutant JAK2-V617F (VF) mice. However, pegIFN-α in VF;Dnmt3aΔ/Δ (VF;DmΔ/Δ) mice worsened splenomegaly and failed to reduce JAK2-V617F chimerism. Furthermore, LT-HSCs from VF;DmΔ/Δ mice compared with VF were less prone to accumulate DNA damage and exit dormancy upon pegIFN-α treatment. RNA sequencing showed that IFN-α induced stronger upregulation of inflammatory pathways in LT-HSCs from VF;DmΔ/Δ than from VF mice, indicating that the resistance of VF;DmΔ/Δ LT-HSC was not due to failure in IFN-α signaling. Transplantations of bone marrow from pegIFN-α-treated VF;DmΔ/Δ mice gave rise to more aggressive disease in secondary and tertiary recipients. Liquid cultures of hematopoietic progenitors from patients with MPN with JAK2-V617F and DNMT3A mutation showed increased percentages of JAK2-V617F-positive colonies upon IFN-α exposure, whereas in patients with JAK2-V617F alone, the percentages of JAK2-V617F-positive colonies decreased or remained unchanged. PegIFN-α combined with 5-azacytidine only partially overcame resistance in VF;DmΔ/Δ mice. However, this combination strongly decreased the JAK2-mutant allele burden in mice carrying VF mutation only, showing potential to inflict substantial damage preferentially to the JAK2-mutant clone.

• MeSH
• buněčná sebeobnova MeSH
• chemorezistence * genetika   MeSH
• DNA methyltransferasa 3A * genetika   MeSH
• DNA-(cytosin-5-)methyltransferasa * genetika   metabolismus   MeSH
• hematopoetické kmenové buňky * metabolismus   patologie   účinky léků   MeSH
• interferon alfa * farmakologie   MeSH
• Janus kinasa 2 * genetika   metabolismus   MeSH
• lidé MeSH
• myeloproliferativní poruchy * genetika   patologie   farmakoterapie   metabolismus   MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• polyethylenglykoly farmakologie   MeSH
• rekombinantní proteiny MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• DNA methyltransferasa 3A * MeSH
• DNA-(cytosin-5-)methyltransferasa * MeSH
• DNMT3A protein, human MeSH Prohlížeč
• Dnmt3a protein, mouse MeSH Prohlížeč
• interferon alfa * MeSH
• JAK2 protein, human MeSH Prohlížeč
• Jak2 protein, mouse MeSH Prohlížeč
• Janus kinasa 2 * MeSH
• peginterferon alfa-2a MeSH Prohlížeč
• polyethylenglykoly MeSH
• rekombinantní proteiny MeSH

Caloric Restriction (CR) has established anti-cancer effects, but its clinical relevance and molecular mechanism remain largely undefined. Here, we investigate CR's impact on several mouse models of Acute Myeloid Leukemias, including Acute Promyelocytic Leukemia, a subtype strongly affected by obesity. After an initial marked anti-tumor effect, lethal disease invariably re-emerges. Initially, CR leads to cell-cycle restriction, apoptosis, and inhibition of TOR and insulin/IGF1 signaling. The relapse, instead, is associated with the non-genetic selection of Leukemia Initiating Cells and the downregulation of double-stranded RNA (dsRNA) sensing and Interferon (IFN) signaling genes. The CR-induced adaptive phenotype is highly sensitive to pharmacological or genetic ablation of LSD1, a lysine demethylase regulating both stem cells and dsRNA/ IFN signaling. CR + LSD1 inhibition leads to the re-activation of dsRNA/IFN signaling, massive RNASEL-dependent apoptosis, and complete leukemia eradication in ~90% of mice. Importantly, CR-LSD1 interaction can be modeled in vivo and in vitro by combining LSD1 ablation with pharmacological inhibitors of insulin/IGF1 or dual PI3K/MEK blockade. Mechanistically, insulin/IGF1 inhibition sensitizes blasts to LSD1-induced death by inhibiting the anti-apoptotic factor CFLAR. CR and LSD1 inhibition also synergize in patient-derived AML and triple-negative breast cancer xenografts. Our data provide a rationale for epi-metabolic pharmacologic combinations across multiple tumors.

• MeSH
• akutní myeloidní leukemie * patologie   MeSH
• histondemethylasy genetika   MeSH
• inzuliny * MeSH
• kalorická restrikce MeSH
• lidé MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• nádorové kmenové buňky patologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• histondemethylasy MeSH
• inzuliny * MeSH

Hematopoietic stem cells (HSCs) ensure blood cell production during the life-time of an organism, and to do so they need to balance self-renewal, proliferation, differentiation, and migration in a steady state as well as in response to stress or injury. Importantly, aberrant proliferation of HSCs leads to hematological malignancies, and thus, tight regulation by various tumor suppressor pathways, including p53, is essential. Protein phosphatase magnesium-dependent 1 delta (PPM1D) is a negative regulator of p53 and promotes cell survival upon induction of genotoxic stress. Truncating mutations in the last exon of PPM1D lead to the production of a stable, enzymatically active protein and are commonly associated with clonal hematopoiesis. Using a transgenic mouse model, we demonstrate that truncated PPM1D reduces self-renewal of HSCs in basal conditions but promotes the development of aggressive AML after exposure to ionizing radiation. Inhibition of PPM1D suppressed the colony growth of leukemic stem and progenitor cells carrying the truncated PPM1D, and remarkably, it provided protection against irradiation-induced cell growth. Altogether, we demonstrate that truncated PPM1D affects HSC maintenance, disrupts normal hematopoiesis, and that its inhibition could be beneficial in the context of therapy-induced AML.

• MeSH
• akutní myeloidní leukemie * genetika   MeSH
• mutace MeSH
• myši MeSH
• nádorový supresorový protein p53 * genetika   MeSH
• poškození DNA MeSH
• proliferace buněk MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• nádorový supresorový protein p53 * MeSH
• Ppm1d protein, mouse MeSH Prohlížeč

Chronic inflammation represents a major threat to human health since long-term systemic inflammation is known to affect distinct tissues and organs. Recently, solid evidence demonstrated that chronic inflammation affects hematopoiesis; however, how chronic inflammation affects hematopoietic stem cells (HSCs) on the mechanistic level is poorly understood. Here, we employ a mouse model of chronic multifocal osteomyelitis (CMO) to assess the effects of a spontaneously developed inflammatory condition on HSCs. We demonstrate that hematopoietic and nonhematopoietic compartments in CMO BM contribute to HSC expansion and impair their function. Remarkably, our results suggest that the typical features of murine multifocal osteomyelitis and the HSC phenotype are mechanistically decoupled. We show that the CMO environment imprints a myeloid gene signature and imposes a pro-inflammatory profile on HSCs. We identify IL-6 and the Jak/Stat3 signaling pathway as critical mediators. However, while IL-6 and Stat3 blockage reduce HSC numbers in CMO mice, only inhibition of Stat3 activity significantly rescues their fitness. Our data emphasize the detrimental effects of chronic inflammation on stem cell function, opening new venues for treatment.

• Klíčová slova
• IL-6/Jak/Stat3, chronic inflammation, chronic multifocal osteomyelitis, hematopoietic stem cells, niche,
• MeSH
• hematopoetické kmenové buňky metabolismus   MeSH
• hematopoéza MeSH
• interleukin-6 * genetika   metabolismus   MeSH
• lidé MeSH
• myši MeSH
• osteomyelitida MeSH
• signální transdukce MeSH
• transkripční faktor STAT3 genetika   metabolismus   MeSH
• zánět * metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• interleukin-6 * MeSH
• STAT3 protein, human MeSH Prohlížeč
• transkripční faktor STAT3 MeSH

Adrenal glands are the major organs releasing catecholamines and regulating our stress response. The mechanisms balancing generation of adrenergic chromaffin cells and protecting against neuroblastoma tumors are still enigmatic. Here we revealed that serotonin (5HT) controls the numbers of chromaffin cells by acting upon their immediate progenitor "bridge" cells via 5-hydroxytryptamine receptor 3A (HTR3A), and the aggressive HTR3Ahigh human neuroblastoma cell lines reduce proliferation in response to HTR3A-specific agonists. In embryos (in vivo), the physiological increase of 5HT caused a prolongation of the cell cycle in "bridge" progenitors leading to a smaller chromaffin population and changing the balance of hormones and behavioral patterns in adulthood. These behavioral effects and smaller adrenals were mirrored in the progeny of pregnant female mice subjected to experimental stress, suggesting a maternal-fetal link that controls developmental adaptations. Finally, these results corresponded to a size-distribution of adrenals found in wild rodents with different coping strategies.

• MeSH
• chromafinní buňky * metabolismus   MeSH
• katecholaminy metabolismus   MeSH
• myši MeSH
• nadledviny metabolismus   MeSH
• neuroblastom * metabolismus   MeSH
• serotonin metabolismus   MeSH
• těhotenství MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• těhotenství MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• katecholaminy MeSH
• serotonin MeSH

Glioblastoma cancer-stem like cells (GSCs) display marked resistance to ionizing radiation (IR), a standard of care for glioblastoma patients. Mechanisms underpinning radio-resistance of GSCs remain largely unknown. Chromatin state and the accessibility of DNA lesions to DNA repair machineries are crucial for the maintenance of genomic stability. Understanding the functional impact of chromatin remodeling on DNA repair in GSCs may lay the foundation for advancing the efficacy of radio-sensitizing therapies. Here, we present the results of a high-content siRNA microscopy screen, revealing the transcriptional elongation factor SPT6 to be critical for the genomic stability and self-renewal of GSCs. Mechanistically, SPT6 transcriptionally up-regulates BRCA1 and thereby drives an error-free DNA repair in GSCs. SPT6 loss impairs the self-renewal, genomic stability and tumor initiating capacity of GSCs. Collectively, our results provide mechanistic insights into how SPT6 regulates DNA repair and identify SPT6 as a putative therapeutic target in glioblastoma.

• MeSH
• apoptóza MeSH
• genový knockdown MeSH
• glioblastom genetika   patologie   MeSH
• HEK293 buňky MeSH
• heterografty MeSH
• ionizující záření MeSH
• kontrolní body buněčného cyklu MeSH
• lidé MeSH
• malá interferující RNA genetika   MeSH
• myši inbrední BALB C MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• nádorové kmenové buňky * patologie   MeSH
• nádory mozku genetika   MeSH
• nestabilita genomu * MeSH
• oprava DNA * MeSH
• protein BRCA1 MeSH
• regulace genové exprese u nádorů MeSH
• tolerance záření MeSH
• transkripční faktory genetika   metabolismus   MeSH
• transkriptom MeSH
• umlčování genů MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• BRCA1 protein, human MeSH Prohlížeč
• malá interferující RNA MeSH
• protein BRCA1 MeSH
• SUPT6H protein, human MeSH Prohlížeč
• transkripční faktory MeSH

Glioblastoma-initiating cells (GICs) are self-renewing tumorigenic sub-populations, contributing to therapeutic resistance via decreased sensitivity to ionizing radiation (IR). GIC survival following IR is attributed to an augmented response to genotoxic stress. We now report that GICs are primed to handle additional stress due to basal activation of single-strand break repair (SSBR), the main DNA damage response pathway activated by reactive oxygen species (ROS), compared with non-GICs. ROS levels were higher in GICs and likely contributed to the oxidative base damage and single-strand DNA breaks found elevated in GICs. To tolerate constitutive DNA damage, GICs exhibited a reliance on the key SSBR mediator, poly-ADP-ribose polymerase (PARP), with decreased viability seen upon small molecule inhibition to PARP. PARP inhibition (PARPi) sensitized GICs to radiation and inhibited growth, self-renewal, and DNA damage repair. In vivo treatment with PARPi and radiotherapy attenuated radiation-induced enrichment of GICs and inhibited the central cancer stem cell phenotype of tumor initiation. These results indicate that elevated PARP activation within GICs permits exploitation of this dependence, potently augmenting therapeutic efficacy of IR against GICs. In addition, our results support further development of clinical trials with PARPi and radiation in glioblastoma.

• MeSH
• apoptóza účinky léků   MeSH
• fenotyp MeSH
• ftalaziny farmakologie   MeSH
• glioblastom metabolismus   patologie   terapie   MeSH
• lidé MeSH
• myši nahé MeSH
• myši MeSH
• nádorové kmenové buňky účinky léků   metabolismus   patologie   MeSH
• oprava DNA MeSH
• PARP inhibitory MeSH
• piperaziny farmakologie   MeSH
• poly(ADP-ribosa)polymerasy metabolismus   MeSH
• poškození DNA MeSH
• proliferace buněk účinky léků   MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• viabilita buněk účinky léků   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• vztahy mezi strukturou a aktivitou MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• ftalaziny MeSH
• olaparib MeSH Prohlížeč
• PARP inhibitory MeSH
• piperaziny MeSH
• poly(ADP-ribosa)polymerasy MeSH
• reaktivní formy kyslíku MeSH