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BioRxiv : the Preprint Server For... Dec 2023Meiotic progression requires coordinated assembly and disassembly of protein complexes involved in chromosome synapsis and meiotic recombination. The AAA+ ATPase TRIP13...
Meiotic progression requires coordinated assembly and disassembly of protein complexes involved in chromosome synapsis and meiotic recombination. The AAA+ ATPase TRIP13 and its orthologue Pch2 are instrumental in remodeling HORMA domain proteins. Meiosis-specific HORMAD proteins are associated with unsynapsed chromosome axes but depleted from the synaptonemal complex (SC) of synapsed chromosome homologues. Here we report that TRIP13 localizes to the synapsed SC in early pachytene spermatocytes and to telomeres throughout meiotic prophase I. Loss of TRIP13 leads to meiotic arrest and thus sterility in both sexes. -null meiocytes exhibit abnormal persistence of HORMAD1 and HOMRAD2 on synapsed SC and chromosome asynapsis that preferentially affects XY and centromeric ends. These findings confirm the previously reported phenotypes of the hypomorph alleles. heterozygous () mice also exhibit meiotic defects that are less severe than the -null mice, showing that TRIP13 is a dosage-sensitive regulator of meiosis. Localization of TRIP13 to the synapsed SC is independent of SC axial element proteins such as REC8 and SYCP2/SYCP3. The N- or C-terminal FLAG-tagged TRIP13 proteins are functional and recapitulate the localization of native TRIP13 to SC and telomeres in knockin mice. Therefore, the evolutionarily conserved localization of TRIP13/Pch2 to the synapsed chromosomes provides an explanation for dissociation of HORMA domain proteins upon chromosome synapsis in diverse organisms.
PubMed: 37808842
DOI: 10.1101/2023.09.25.559355 -
Cancers Aug 2023Philadelphia chromosome-negative chronic myeloproliferative neoplasms (MPNs) arise due to acquired somatic driver mutations in stem cells and develop over 10-30 years... (Review)
Review
Philadelphia chromosome-negative chronic myeloproliferative neoplasms (MPNs) arise due to acquired somatic driver mutations in stem cells and develop over 10-30 years from the earliest cancer stages (essential thrombocythemia, polycythemia vera) towards the advanced myelofibrosis stage with bone marrow failure. The mutation is the most prevalent driver mutation. Chronic inflammation is considered to be a major pathogenetic player, both as a trigger of MPN development and as a driver of disease progression. Chronic inflammation in MPNs is characterized by persistent connective tissue remodeling, which leads to organ dysfunction and ultimately, organ failure, due to excessive accumulation of extracellular matrix (ECM). Considering that MPNs are acquired clonal stem cell diseases developing in an inflammatory microenvironment in which the hematopoietic cell populations are progressively replaced by stromal proliferation-"a wound that never heals"-we herein aim to provide a comprehensive review of previous promising research in the field of circulating ECM fragments in the diagnosis, treatment and monitoring of MPNs. We address the rationales and highlight new perspectives for the use of circulating ECM protein fragments as biologically plausible, noninvasive disease markers in the management of MPNs.
PubMed: 37686599
DOI: 10.3390/cancers15174323 -
NPJ Precision Oncology Dec 2023Philadelphia chromosome (Ph)-like acute lymphoblastic leukemia (ALL) is a subset of ALL that demonstrated a high treatment failure rate. One of the hallmarks of Ph-like...
Philadelphia chromosome (Ph)-like acute lymphoblastic leukemia (ALL) is a subset of ALL that demonstrated a high treatment failure rate. One of the hallmarks of Ph-like ALL is PDGFRB gene fusion, with fusion partner proteins often harboring dimerization domains and enhancing the kinase activity of PDGFRB. We determined a novel oncogenic PDGFRB fusion gene, NRIP1::PDGFRB, from a pediatric patient with ALL, encoding a protein with the carboxy-terminal kinase domain of PDGFRB, without the partner peptide. We confirmed the oncogenic potential of NRIP1::PDGFRB in vitro and the efficacy of all ABL1-specific inhibitor generations, including imatinib, dasatinib, nilotinib, and ponatinib, in suppressing this potential. PDGFRB activation mechanism may include juxtamembrane domain truncation in the predicted peptide. In conclusion, we determined a novel fusion gene pattern in Ph-like ALL.
PubMed: 38071343
DOI: 10.1038/s41698-023-00485-7 -
BioRxiv : the Preprint Server For... Nov 2023During mitosis, condensin activity interferes with interphase chromatin structures. Here, we generated condensin-free mitotic chromosomes to investigate genome folding...
During mitosis, condensin activity interferes with interphase chromatin structures. Here, we generated condensin-free mitotic chromosomes to investigate genome folding principles. Co-depletion of condensin I and II, but neither alone, triggered mitotic chromosome compartmentalization in ways that differ from interphase. Two distinct euchromatic compartments, indistinguishable in interphase, rapidly emerged upon condensin loss with different interaction preferences and dependence on H3K27ac. Constitutive heterochromatin gradually self-aggregated and co-compartmentalized with the facultative heterochromatin, contrasting with their separation during interphase. While topologically associating domains (TADs) and CTCF/cohesin mediated structural loops remained undetectable, cis-regulatory element contacts became apparent, providing an explanation for their quick re-establishment during mitotic exit. HP1 proteins, which are thought to partition constitutive heterochromatin, were absent from mitotic chromosomes, suggesting, surprisingly, that constitutive heterochromatin can self-aggregate without HP1. Indeed, in cells traversing from M- to G1-phase in the combined absence of HP1α, HP1β and HP1γ, re-established constitutive heterochromatin compartments normally. In sum, "clean-slate" condensing-deficient mitotic chromosomes illuminate mechanisms of genome compartmentalization not revealed in interphase cells.
PubMed: 38014261
DOI: 10.1101/2023.11.09.566494 -
World Journal of Oncology Apr 2024Asciminib is approved for treating patients with chronic-phase chronic myeloid leukemia who were previously treated with two or more tyrosine kinase inhibitors or those...
BACKGROUND
Asciminib is approved for treating patients with chronic-phase chronic myeloid leukemia who were previously treated with two or more tyrosine kinase inhibitors or those with mutation. However, the mechanisms underlying asciminib resistance remain unclear.
METHODS
In this study, we established a new asciminib-resistant cell line. We examined gene mutation analysis and the effects of conventional chronic myelogenous leukemia inhibitors.
RESULTS
Direct sequencing revealed and mutations in asciminib-resistant cells. Ponatinib and omacetaxine were effective against asciminib-resistant cells.
CONCLUSIONS
and mutations are extremely resistant to asciminib. Ponatinib and omacetaxine show potential for treating asciminib-resistant chronic myeloid leukemia.
PubMed: 38545482
DOI: 10.14740/wjon1818 -
The Oncologist Jul 2023Asciminib is an allosteric high-affinity tyrosine kinase inhibitor (TKI) of the BCR-ABL1 protein kinase. This kinase is translated from the Philadelphia chromosome in... (Randomized Controlled Trial)
Randomized Controlled Trial
The EMA Assessment of Asciminib for the Treatment of Adult Patients With Philadelphia Chromosome-Positive Chronic Myeloid Leukemia in Chronic Phase Who Were Previously Treated With at Least Two Tyrosine Kinase Inhibitors.
Asciminib is an allosteric high-affinity tyrosine kinase inhibitor (TKI) of the BCR-ABL1 protein kinase. This kinase is translated from the Philadelphia chromosome in chronic myeloid leukemia (CML). Marketing authorization for asciminib was granted on August 25, 2022 by the European Commission. The approved indication was for patients with Philadelphia chromosome-positive CML in the chronic phase which have previously been treated with at least 2 TKIs. Clinical efficacy and safety of asciminib were evaluated in the open-label, randomized, phase III ASCEMBL study. The primary endpoint of this trial was major molecular response (MMR) rate at 24 weeks. A significant difference in MRR rate was shown between the asciminib treated population and the bosutinib control group (25.5% vs. 13.2%, respectively, P = .029). In the asciminib cohort, adverse reactions of at least grade 3 with an incidence ≥ 5% were thrombocytopenia, neutropenia, increased pancreatic enzymes, hypertension, and anemia. The aim of this article is to summarize the scientific review of the application which led to the positive opinion by the European Medicines Agency's Committee for Medicinal Products for Human Use.
Topics: Adult; Humans; Antineoplastic Agents; Drug Resistance, Neoplasm; Fusion Proteins, bcr-abl; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Philadelphia Chromosome; Protein Kinase Inhibitors; Tyrosine Kinase Inhibitors
PubMed: 37141403
DOI: 10.1093/oncolo/oyad119 -
Data in Brief Oct 2023Tumorous cancer has been a widely known and well-studied medical phenomenon; however, rare diseases like Myeloproliferative Neoplasm (MPN) have received less attention,...
Tumorous cancer has been a widely known and well-studied medical phenomenon; however, rare diseases like Myeloproliferative Neoplasm (MPN) have received less attention, leading to delayed diagnosis. Despite the availability of advanced technology in diagnostic tools that can boost the procedure, the morphological assessment of bone marrow trephine (BMT) images remains critical to confirm and differentiate MPN subtypes. This paper reports a histopathological imagery dataset that was created to focus on the most common MPN from the Philadelphia Chromosome (Ph)-negative type, namely Essential Thrombocythemia (ET), Polycythemia Vera (PV), and Primary Myelofibrosis (MF). The dataset consisted of 300 BMT images that can be used to enable computer vision applications, such as image segmentation, disease classification, and object recognition, in assisting the classification of the MPN disease. Ethical approval was obtained from the Ministry of Health, Malaysia and the bone marrow trephine images were captured using a digital microscope from the Olympus model (BX41 Dual head microscope) with x10, x20, and x40 lens types. The development of comprehensive tools deployed from this dataset can assist medical practitioners in diagnosing diseases, thus overcoming the current challenges.
PubMed: 37636134
DOI: 10.1016/j.dib.2023.109484 -
EMBO Reports Oct 2023After fertilization, remodeling of the oocyte and sperm genomes is essential to convert these highly differentiated and transcriptionally quiescent cells into early...
After fertilization, remodeling of the oocyte and sperm genomes is essential to convert these highly differentiated and transcriptionally quiescent cells into early cleavage-stage blastomeres that are transcriptionally active and totipotent. This developmental transition is accompanied by cell cycle adaptation, such as lengthening or shortening of the gap phases G1 and G2. However, regulation of these cell cycle changes is poorly understood, especially in mammals. Checkpoint kinase 1 (CHK1) is a protein kinase that regulates cell cycle progression in somatic cells. Here, we show that CHK1 regulates cell cycle progression in early mouse embryos by restraining CDK1 kinase activity due to CDC25A phosphatase degradation. CHK1 kinase also ensures the long G2 phase needed for genome activation and reprogramming gene expression in two-cell stage mouse embryos. Finally, Chk1 depletion leads to DNA damage and chromosome segregation errors that result in aneuploidy and infertility.
PubMed: 37694680
DOI: 10.15252/embr.202256530 -
Journal of Autoimmunity Sep 2023Systemic lupus erythematosus (SLE) is a highly female-biased systemic autoimmune disease, but the molecular basis for this female bias remains incompletely elucidated. B...
OBJECTIVE
Systemic lupus erythematosus (SLE) is a highly female-biased systemic autoimmune disease, but the molecular basis for this female bias remains incompletely elucidated. B and T lymphocytes from patients with SLE and female-biased mouse models of SLE exhibit features of epigenetic dysregulation on the X chromosome which may contribute to this strong female bias. We therefore examined the fidelity of dynamic X-chromosome inactivation maintenance (dXCIm) in the pathogenesis of two murine models of spontaneous lupus-NZM2328 and MRL/lpr-with disparate levels of female-bias to determine whether impaired dXCIm contributes to the female bias of disease.
METHODS
CD23 B cells and CD3 T cells were purified from age-matched C57BL/6 (B6), MRL/lpr, and NZM2328 male and female mice, activated in vitro, and processed for Xist RNA fluorescence in situ hybridization, H3K27me3 immunofluorescence imaging, qPCR, and RNA sequencing analyses.
RESULTS
The dynamic relocalization of Xist RNA and the canonical heterochromatin mark, H3K27me3, to the inactive X chromosome was preserved in CD23 B cells, but impaired in activated CD3 T cells from the MRL/lpr model (p < 0.01 vs. B6), and even more impaired in the heavily female-biased NZM2328 model (p < 0.001 vs. B6; p < 0.05 vs. MRL/lpr). RNAseq of activated T cells from NZM2328 mice revealed the female-biased upregulation of 32 X-linked genes distributed broadly across the X chromosome, many of which have roles in immune function. Many genes encoding Xist RNA-interacting proteins were also differentially expressed and predominantly downregulated, which may account for the observed mislocalization of Xist RNA to the inactive X chromosome.
CONCLUSIONS
Although evident in T cells from both the MRL/lpr and NZM2328 models of spontaneous SLE, impaired dXCIm is more severe in the heavily female-biased NZM2328 model. The aberrant X-linked gene dosage in female NZM2328 mice may contribute towards the development of female-biased immune responses in SLE-prone hosts. These findings provide important insights into the epigenetic mechanisms contributing to female-biased autoimmunity.
Topics: X Chromosome Inactivation; T-Lymphocytes; Female; Animals; Mice; Lupus Erythematosus, Systemic; B-Lymphocytes; Mice, Inbred C57BL; Male; Sex Factors; Lymphocyte Activation; Disease Models, Animal; Humans; Gene Dosage; RNA, Long Noncoding; Protein Binding; Autoimmunity
PubMed: 37399593
DOI: 10.1016/j.jaut.2023.103084 -
Annals of Medicine Dec 2023There is a lack of evidence regarding whether combination therapy of hypomethylating agents (HMAs) has better outcomes than HMA monotherapy in patients with Philadelphia... (Meta-Analysis)
Meta-Analysis Review
Efficacy and safety of combination therapies vs monotherapy of hypomethylating agents in accelerated or blast phase of Philadelphia negative myeloproliferative neoplasms: a systematic review and meta-analysis.
BACKGROUND
There is a lack of evidence regarding whether combination therapy of hypomethylating agents (HMAs) has better outcomes than HMA monotherapy in patients with Philadelphia chromosome-negative accelerated or blast phase myeloproliferative neoplasms (MPN-AP/BP).
MATERIALS AND METHODS
Pubmed, Embase, Web of Science and Cochrane library databases were searched for studies from inception of each database until 31 December 2021. Data extraction and synthesis were conducted following the PRISMA reporting guideline.
RESULTS
It was found that HMAs plus venetoclax therapy yielded a higher CR/CRi rate than HMAs alone [36% vs 19%, = .0204] and a higher CR rate than HMAs plus ruxolitinib [22% vs 8%, = .0313]. HMAs plus ruxolitinib combination showed a higher ORR than HMA monotherapy [45% vs 30%, = .0395], but there was no improvement in CR/CRi. The one-year and two-year OS rate for patients treated with HMAs plus venetoclx/ruxolitinib demonstrated a trend towards prolonged survival than HMAs alone [HMAs plus venetoclax: 24% vs 11%, = .1295 and 12% vs 3%, = .2357; HMAs plus ruxolitinib: 25% vs 11%, = .0774 and 33% vs 3%, = .051].
CONCLUSION
It was confirmed that HMA in combination with venetoclax is an effective and well-tolerated option in MPN-AP/BP patients in pre- as well as post-haematopoietic stem cell transplantation settings. HMA plus ruxolitinib therapy was revealed to be effective in patients with MPN-AP.Key MessagesCombination therapy with HMAs and venetoclax/ruxolitinib was associated with improved outcomes than HMAs alone in MPN-AP/BP patients.Further large-scale randomized controlled trials are needed to confirm regarding to the optimal treatment for this patient population.
Topics: Humans; Treatment Outcome; Blast Crisis; Bridged Bicyclo Compounds, Heterocyclic
PubMed: 36644935
DOI: 10.1080/07853890.2022.2164611