Patients with lower-risk myelodysplastic syndromes (LR-MDS) have a generally favorable prognosis; however, a small proportion of cases progress rapidly. This study aimed to define molecular biomarkers predictive of LR-MDS progression and to uncover cellular pathways contributing to malignant transformation. The mutational landscape was analyzed in 214 LR-MDS patients, and at least one mutation was detected in 137 patients (64%). Mutated RUNX1 was identified as the main molecular predictor of rapid progression by statistics and machine learning. To study the effect of mutated RUNX1 on pathway regulation, the expression profiles of CD34 + cells from LR-MDS patients with RUNX1 mutations were compared to those from patients without RUNX1 mutations. The data suggest that RUNX1-unmutated LR-MDS cells are protected by DNA damage response (DDR) mechanisms and cellular senescence as an antitumor cellular barrier, while RUNX1 mutations may be one of the triggers of malignant transformation. Dysregulated DDR and cellular senescence were also observed at the functional level by detecting γH2AX expression and β-galactosidase activity. Notably, the expression profiles of RUNX1-mutated LR-MDS resembled those of higher-risk MDS at diagnosis. This study demonstrates that incorporating molecular data improves LR-MDS risk stratification and that mutated RUNX1 is associated with a suppressed defense against LR-MDS progression.

• MeSH
• akutní myeloidní leukemie * genetika   MeSH
• lidé MeSH
• mutace MeSH
• myelodysplastické syndromy * patologie   MeSH
• nádorová transformace buněk genetika   metabolismus   MeSH
• prognóza MeSH
• protein PEBP2A2 genetika   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• protein PEBP2A2 MeSH
• RUNX1 protein, human MeSH Prohlížeč

Inflammatory and oncogenic signaling, both known to challenge genome stability, are key drivers of BCR-ABL-positive chronic myeloid leukemia (CML) and JAK2 V617F-positive chronic myeloproliferative neoplasms (MPNs). Despite similarities in chronic inflammation and oncogene signaling, major differences in disease course exist. Although BCR-ABL has robust transformation potential, JAK2 V617F-positive polycythemia vera (PV) is characterized by a long and stable latent phase. These differences reflect increased genomic instability of BCR-ABL-positive CML, compared to genome-stable PV with rare cytogenetic abnormalities. Recent studies have implicated BCR-ABL in the development of a "mutator" phenotype fueled by high oxidative damage, deficiencies of DNA repair, and defective ATR-Chk1-dependent genome surveillance, providing a fertile ground for variants compromising the ATM-Chk2-p53 axis protecting chronic phase CML from blast crisis. Conversely, PV cells possess multiple JAK2 V617F-dependent protective mechanisms, which ameliorate replication stress, inflammation-mediated oxidative stress and stress-activated protein kinase signaling, all through up-regulation of RECQL5 helicase, reactive oxygen species buffering system, and DUSP1 actions. These attenuators of genome instability then protect myeloproliferative progenitors from DNA damage and create a barrier preventing cellular stress-associated myelofibrosis. Therefore, a better understanding of BCR-ABL and JAK2 V617F roles in the DNA damage response and disease pathophysiology can help to identify potential dependencies exploitable for therapeutic interventions.

• Klíčová slova
• ATM-Chk2 pathway, DNA damage response, chronic myeloid leukemia, polycythemia vera,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

OBJECTIVE: Aseptic loosening (AL) is the most frequent long-term reason for revision of total knee arthroplasty (TKA) affecting about 15-20% patients within 20 years after the surgery. Although there is a solid body of evidence about the crucial role of inflammation in the AL pathogenesis, scared information on inflammation signature and its time-axis in tissues around TKA exists. DESIGN: The inflammation protein signatures in pseudosynovial tissues collected at revision surgery from patients with AL (AL, n = 12) and those with no clinical/radiographic signs of AL (non-AL, n = 9) were investigated by Proximity Extension Assay (PEA)-Immunoassay and immunohistochemistry. RESULTS: AL tissues had elevated levels of TNF-family members sTNFR2, TNFSF14, sFasL, sBAFF, cytokines/chemokines IL8, CCL2, IL1RA/IL36, sIL6R, and growth factors sAREG, CSF1, comparing to non-AL. High interindividual variability in protein levels was evident particularly in non-AL. Levels of sTNFR2, sBAFF, IL8, sIL6R, and MPO discriminated between AL and non-AL and were associated with the time from index surgery, suggesting the cumulative character of inflammatory osteolytic response to prosthetic byproducts. The source of elevated inflammatory molecules was macrophages and multinucleated osteoclast-like cells in AL and histiocytes and osteoclast-like cells in non-AL tissues, respectively. All proteins were present in higher levels in osteoclast-like cells than in macrophages. CONCLUSIONS: Our study revealed a differential inflammation signature between AL and non-AL stages of TKA. It also highlighted the unique patient's response to TKA in non-AL stages. Further confirmation of our preliminary results on a larger cohort is needed. Analysis of the time-axis of processes ongoing around TKA implantation may help to understand the mechanisms driving periprosthetic bone resorption needed for diagnostic/preventative strategies.

• MeSH
• cytokiny metabolismus   MeSH
• histiocyty metabolismus   patologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• makrofágy metabolismus   patologie   MeSH
• osteoklasty metabolismus   patologie   MeSH
• reoperace MeSH
• resorpce kosti komplikace   metabolismus   patofyziologie   chirurgie   MeSH
• selhání protézy škodlivé účinky   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• totální endoprotéza kolene škodlivé účinky   MeSH
• zánět komplikace   metabolismus   patofyziologie   chirurgie   MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• cytokiny MeSH

Inflammatory and oncogenic signaling converge in disease evolution of BCR-ABL-negative myeloproliferative neoplasms, clonal hematopoietic stem cell disorders characterized by gain-of-function mutation in JAK2 kinase (JAK2V617F), with highest prevalence in patients with polycythemia vera (PV). Despite the high risk, DNA-damaging inflammatory microenvironment, PV progenitors tend to preserve their genomic stability over decades until their progression to post-PV myelofibrosis/acute myeloid leukemia. Using induced pluripotent stem cells-derived CD34+ progenitor-enriched cultures from JAK2V617F+ PV patient and from JAK2 wild-type healthy control, CRISPR-modified HEL cells and patients' bone marrow sections from different disease stages, we demonstrate that JAK2V617F induces an intrinsic IFNγ- and NF-κB-associated inflammatory program, while suppressing inflammation-evoked DNA damage both in vitro and in vivo. We show that cells with JAK2V617F tightly regulate levels of inflammatory cytokines-induced reactive oxygen species, do not fully activate the ATM/p53/p21waf1 checkpoint and p38/JNK MAPK stress pathway signaling when exposed to inflammatory cytokines, suppress DNA single-strand break repair genes' expression yet overexpress the dual-specificity phosphatase (DUSP) 1. RNAi-mediated knock-down and pharmacological inhibition of DUSP1, involved in p38/JNK deactivation, in HEL cells reveals growth addiction to DUSP1, consistent with enhanced DNA damage response and apoptosis in DUSP1-inhibited parental JAK2V617F+ cells, but not in CRISPR-modified JAK2 wild-type cells. Our results indicate that the JAK2V617F+ PV progenitors utilize DUSP1 activity as a protection mechanism against DNA damage accumulation, promoting their proliferation and survival in the inflammatory microenvironment, identifying DUSP1 as a potential therapeutic target in PV.

• MeSH
• cytokiny genetika   metabolismus   MeSH
• fosfatasa 1 s dvojí specificitou genetika   MeSH
• hematopoetické kmenové buňky patologie   MeSH
• indukované pluripotentní kmenové buňky patologie   MeSH
• Janus kinasa 2 genetika   MeSH
• lidé MeSH
• mutace MeSH
• nádorové buněčné linie MeSH
• nádorové mikroprostředí MeSH
• oxidační stres * MeSH
• polycythaemia vera genetika   MeSH
• poškození DNA * MeSH
• proliferace buněk * MeSH
• reprodukovatelnost výsledků MeSH
• transkripční faktor STAT1 metabolismus   MeSH
• zánět metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• cytokiny MeSH
• DUSP1 protein, human MeSH Prohlížeč
• fosfatasa 1 s dvojí specificitou MeSH
• JAK2 protein, human MeSH Prohlížeč
• Janus kinasa 2 MeSH
• STAT1 protein, human MeSH Prohlížeč
• transkripční faktor STAT1 MeSH

Myelodysplastic syndromes (MDS) represent a heterogeneous group of clonal stem cell disorders characterized by ineffective hematopoiesis frequently progressing into acute myeloid leukemia (AML), with emerging evidence implicating aberrant bone marrow (BM) microenvironment and inflammation-related changes. 5-azacytidine (5-AC) represents standard MDS treatment. Besides inhibiting DNA/RNA methylation, 5-AC has been shown to induce DNA damage and apoptosis in vitro. To provide insights into in vivo effects, we assessed the proinflammatory cytokines alterations during MDS progression, cytokine changes after 5-AC, and contribution of inflammatory comorbidities to the cytokine changes in MDS patients. We found that IL8, IP10/CXCL10, MCP1/CCL2 and IL27 were significantly elevated and IL12p70 decreased in BM of MDS low-risk, high-risk and AML patients compared to healthy donors. Repeated sampling of the high-risk MDS patients undergoing 5-AC therapy revealed that the levels of IL8, IL27 and MCP1 in BM plasma were progressively increasing in agreement with in vitro experiments using several cancer cell lines. Moreover, the presence of inflammatory diseases correlated with higher levels of IL8 and MCP1 in low-risk but not in high-risk MDS. Overall, all forms of MDS feature a deregulated proinflammatory cytokine landscape in the BM and such alterations are further augmented by therapy of MDS patients with 5-AC.

• Klíčová slova
• 5-azacytidine, DNA damage, bone marrow plasma, cytokines, inflammation, myelodysplastic syndromes,
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Cellular senescence provides a biological barrier against tumor progression, often associated with oncogene-induced replication and/or oxidative stress, cytokine production and DNA damage response (DDR), leading to persistent cell-cycle arrest. While cytokines such as tumor necrosis factor-alpha (TNFα) and interferon gamma (IFNγ) are important components of senescence-associated secretome and induce senescence in, for example, mouse pancreatic β-cancer cell model, their downstream signaling pathway(s) and links with oxidative stress and DDR are mechanistically unclear. Using human and mouse normal and cancer cell models, we now show that TNFα and IFNγ induce NADPH oxidases Nox4 and Nox1, reactive oxygen species (ROS), DDR signaling and premature senescence. Unlike mouse tumor cells that required concomitant presence of IFNγ and TNFα, short exposure to IFNγ alone was sufficient to induce Nox4, Nox1 and DDR in human cells. siRNA-mediated knockdown of Nox4 but not Nox1 decreased IFNγ-induced DDR. The expression of Nox4/Nox1 required Janus kinase (JAK)/signal transducers and activators of transcription (STAT) signaling and the effect was mediated by downstream activation of transforming growth factor-beta (TGFβ) secretion and consequent autocrine/paracrine activation of the TGFβ/Smad pathway. Furthermore, the expression of adenine nucleotide translocase 2 (ANT2) was suppressed by IFNγ contributing to elevation of ROS and DNA damage. In contrast to mouse B16 cells, inability of TC-1 cells to respond to IFNγ/TNFα by DDR and senescence correlated with the lack of TGFβ and Nox4 response, supporting the role of ROS induced by NADPH oxidases in cytokine-induced senescence. Overall, our data reveal differences between cytokine effects in mouse and human cells, and mechanistically implicate the TGFβ/SMAD pathway, via induction of NADPH oxidases and suppression of ANT2, as key mediators of IFNγ/TNFα-evoked genotoxicity and cellular senescence.

• MeSH
• enzymová indukce účinky léků   MeSH
• interferon gama farmakologie   MeSH
• lidé MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• NADPH-oxidasa 1 MeSH
• NADPH-oxidasa 4 MeSH
• NADPH-oxidasy biosyntéza   genetika   MeSH
• oxidační stres účinky léků   MeSH
• poškození DNA * MeSH
• proteiny Smad metabolismus   MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• regulace genové exprese u nádorů MeSH
• signální transdukce účinky léků   MeSH
• stárnutí buněk účinky léků   MeSH
• TNF-alfa farmakologie   MeSH
• transformující růstový faktor beta metabolismus   MeSH
• transkripční faktory STAT metabolismus   MeSH
• translokátor adeninových nukleotidů 2 metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• interferon gama MeSH
• NADPH-oxidasa 1 MeSH
• NADPH-oxidasa 4 MeSH
• NADPH-oxidasy MeSH
• NOX1 protein, human MeSH Prohlížeč
• NOX4 protein, human MeSH Prohlížeč
• proteiny Smad MeSH
• reaktivní formy kyslíku MeSH
• TNF-alfa MeSH
• transformující růstový faktor beta MeSH
• transkripční faktory STAT MeSH
• translokátor adeninových nukleotidů 2 MeSH

Both Myc and Ras oncogenes impact cellular metabolism, deregulate redox homeostasis and trigger DNA replication stress (RS) that compromises genomic integrity. However, how are such oncogene-induced effects evoked and temporally related, to what extent are these kinetic parameters shared by Myc and Ras, and how are these cellular changes linked with oncogene-induced cellular senescence in different cell context(s) remain poorly understood. Here, we addressed the above-mentioned open questions by multifaceted comparative analyses of human cellular models with inducible expression of c-Myc and H-RasV12 (Ras), two commonly deregulated oncoproteins operating in a functionally connected signaling network. Our study of DNA replication parameters using the DNA fiber approach and time-course assessment of perturbations in glycolytic flux, oxygen consumption and production of reactive oxygen species (ROS) revealed the following results. First, overabundance of nuclear Myc triggered RS promptly, already after one day of Myc induction, causing slow replication fork progression and fork asymmetry, even before any metabolic changes occurred. In contrast, Ras overexpression initially induced a burst of cell proliferation and increased the speed of replication fork progression. However, after several days of induction Ras caused bioenergetic metabolic changes that correlated with slower DNA replication fork progression and the ensuing cell cycle arrest, gradually leading to senescence. Second, the observed oncogene-induced RS and metabolic alterations were cell-type/context dependent, as shown by comparative analyses of normal human BJ fibroblasts versus U2-OS sarcoma cells. Third, the energy metabolic reprogramming triggered by Ras was more robust compared to impact of Myc. Fourth, the detected oncogene-induced oxidative stress was due to ROS (superoxide) of non-mitochondrial origin and mitochondrial OXPHOS was reduced (Crabtree effect). Overall, our study provides novel insights into oncogene-evoked metabolic reprogramming, replication and oxidative stress, with implications for mechanisms of tumorigenesis and potential targeting of oncogene addiction.

• Klíčová slova
• DNA damage response, DNA fork progression, Energy metabolism, Myc, Ras, Replication stress,
• MeSH
• buněčná smrt MeSH
• energetický metabolismus genetika   MeSH
• fyziologický stres genetika   MeSH
• geny ras * MeSH
• lidé MeSH
• mitochondrie metabolismus   MeSH
• nádorové buněčné linie MeSH
• oxidační stres genetika   MeSH
• poškození DNA MeSH
• proliferace buněk MeSH
• protoonkogenní proteiny c-myc genetika   MeSH
• replikace DNA genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• protoonkogenní proteiny c-myc MeSH

Cdc7 (cell division cycle 7) kinase together with its activation subunit ASK (also known as Dbf4) play pivotal roles in DNA replication and contribute also to other aspects of DNA metabolism such as DNA repair and recombination. While the biological significance of Cdc7 is widely appreciated, the molecular mechanisms through which Cdc7 kinase regulates these various DNA transactions remain largely obscure, including the role of Cdc7-ASK/Dbf4 under replication stress, a condition associated with diverse (patho)physiological scenarios. In this review, we first highlight the recent findings on a novel pathway that regulates the stability of the human Cdc7-ASK/Dbf4 complex under replication stress, its interplay with ATR-Chk1 signaling, and significance in the RAD18-dependent DNA damage bypass pathway. We also consider Cdc7 function in a broader context, considering both physiological conditions and pathologies associated with enhanced replication stress, particularly oncogenic transformation and tumorigenesis. Furthermore, we integrate the emerging evidence and propose a concept of Cdc7-ASK/Dbf4 contributing to genome integrity maintenance, through interplay with RAD18 that can serve as a molecular switch to dictate DNA repair pathway choice. Finally, we discuss the possibility of targeting Cdc7, particularly in the context of the Cdc7/RAD18-dependent translesion synthesis, as a potential innovative strategy for treatment of cancer.

• Klíčová slova
• Cdc7 kinase, DDK, DNA damage bypass, DNA repair pathway choice, RAD18, TLS, replication checkpoint,
• MeSH
• chromatin metabolismus   MeSH
• DNA vazebné proteiny metabolismus   MeSH
• fyziologický stres * MeSH
• lidé MeSH
• nádory metabolismus   patologie   MeSH
• oprava DNA MeSH
• poškození DNA MeSH
• protein-serin-threoninkinasy genetika   metabolismus   MeSH
• proteiny buněčného cyklu genetika   metabolismus   MeSH
• replikace DNA * MeSH
• replikační počátek MeSH
• signální transdukce MeSH
• ubikvitinligasy MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• CDC7 protein, human MeSH Prohlížeč
• chromatin MeSH
• DBF4 protein, human MeSH Prohlížeč
• DNA vazebné proteiny MeSH
• protein-serin-threoninkinasy MeSH
• proteiny buněčného cyklu MeSH
• RAD18 protein, human MeSH Prohlížeč
• ubikvitinligasy MeSH