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Clinical and Translational Medicine Jul 2023The first-line therapy is effective for the treatment of primary immune thrombocytopenia (ITP); however, maintaining the long-term responses remains challenging....
BACKGROUND
The first-line therapy is effective for the treatment of primary immune thrombocytopenia (ITP); however, maintaining the long-term responses remains challenging. Low-dose decitabine (DAC) has been adopted to treat refractory ITP, while its role in macrophage polarization has not been fully understood. We aimed to investigate the mechanistic role of DAC in M2 macrophage polarization and evaluated its therapeutic effect in ITP.
METHODS
The M2 monocytes were identified by flow cytometry from peripheral blood mononuclear cells in healthy controls (HCs) and ITP patients. The expression of PPARγ, Arg-1, DNMT3b and NLRP3, together with IL-10 plasma levels was measured to examine its function. Bisulfite-sequencing PCR was used to evaluate the methylation status of PPARγ promoter, and the binding affinity of KLF4 was measured by Cut&Tag. A sh-PPARγ THP-1 cell line was created to verify if low-dose DAC-modulated M2 macrophage polarization was PPARγ-dependent. The passive ITP models were used to investigate the therapeutic effects of low-dose DAC and its role in modulating polarization and immunomodulatory function of macrophages. NLRP3 inflammasome and reactive oxygen species were also tested to understand the downstream of PPARγ.
RESULTS
The M2 monocytes with impaired immunoregulation were observed in ITP. After high-dose dexamethasone (HD-DXM) treatment, M2 monocytes increased significantly with the elevated expression of PPARγ, Arg-1 and IL-10 in CR patients. Low-dose DAC promoted M2 macrophage polarization in a PPARγ-dependent way via demethylating the promoter of PPARγ, especially the KLF4 binding sites. Low-dose DAC alleviated ITP mice by restoring the M1/M2 balance and fine-tuning immunomodulatory function of macrophages. The downstream of the PPARγ modulation of M2 macrophage polarization might physiologically antagonize NLRP3 inflammasome.
CONCLUSIONS
Low-dose DAC promoted M2 macrophage polarization due to the demethylation within the promoter of PPARγ, thus enhanced the KLF4 binding affinity in ITP.
Topics: Animals; Mice; PPAR gamma; Decitabine; Interleukin-10; Inflammasomes; Leukocytes, Mononuclear; NLR Family, Pyrin Domain-Containing 3 Protein; Purpura, Thrombocytopenic, Idiopathic; Macrophages
PubMed: 37488670
DOI: 10.1002/ctm2.1344 -
Annals of the Rheumatic Diseases Dec 2023The vacuoles, E1-enzyme, X linked, autoinflammatory and somatic (VEXAS) syndrome is an adult-onset autoinflammatory disease (AID) due to postzygotic variants.
BACKGROUND
The vacuoles, E1-enzyme, X linked, autoinflammatory and somatic (VEXAS) syndrome is an adult-onset autoinflammatory disease (AID) due to postzygotic variants.
OBJECTIVES
To investigate the presence of VEXAS syndrome among patients with adult-onset undiagnosed AID. Additional studies evaluated the mosaicism distribution and the circulating cytokines.
METHODS
Gene analyses were performed by both Sanger and amplicon-based deep sequencing. Patients' data were collected from their medical charts. Cytokines were quantified by Luminex.
RESULTS
Genetic analyses of enrolled patients (n=42) identified 30 patients carrying pathogenic variants, with frequencies compatible for postzygotic variants. All patients were male individuals who presented with a late-onset disease (mean 67.5 years; median 67.0 years) characterised by cutaneous lesions (90%), fever (66.7%), pulmonary manifestations (66.7%) and arthritis (53.3%). Macrocytic anaemia and increased erythrocyte sedimentation rate and ferritin were the most relevant analytical abnormalities. Glucocorticoids ameliorated the inflammatory manifestations, but most patients became glucocorticoid-dependent. Positive responses were obtained when targeting the haematopoietic component of the disease with either decitabine or allogeneic haematopoietic stem cell transplantation. Additional analyses detected the variants in both haematopoietic and non-haematopoietic tissues. Finally, analysis of circulating cytokines did not identify inflammatory mediators of the disease.
CONCLUSION
Thirty patients with adult-onset AID were definitively diagnosed with VEXAS syndrome through genetic analyses. Despite minor interindividual differences, their main characteristics were in concordance with previous reports. We detected for the first time the mosaicism in non-haematopoietic tissue, which questions the previous concept of myeloid-restricted mosaicism and may have conceptual consequences for the disease mechanisms.
Topics: Adult; Humans; Male; Female; Mosaicism; Arthritis; Cytokines; Ferritins; Glucocorticoids; Mutation
PubMed: 37666646
DOI: 10.1136/ard-2023-224460 -
International Journal of Molecular... Dec 2023There has been a widespread adoption of hypomethylating agents (HMA: 5-Azacytidine (5-Aza)/decitabine) and venetoclax (Ven) for the treatment of acute myeloid leukemia... (Review)
Review
There has been a widespread adoption of hypomethylating agents (HMA: 5-Azacytidine (5-Aza)/decitabine) and venetoclax (Ven) for the treatment of acute myeloid leukemia (AML); however, the mechanisms behind the combination's synergy are poorly understood. Monotherapy often encounters resistance, leading to suboptimal outcomes; however, the combination of HMA and Ven has demonstrated substantial improvements in treatment responses. This study elucidates multiple synergistic pathways contributing to this enhanced therapeutic effect. Key mechanisms include HMA-mediated downregulation of anti-apoptotic proteins, notably MCL-1, and the priming of cells for Ven through the induction of genes encoding pro-apoptotic proteins such as Noxa. Moreover, Ven induces sensitization to HMA, induces overcoming resistance by inhibiting the DHODH enzyme, and disrupts antioxidant pathways (Nrf2) induced by HMA. The combination further disrupts oxidative phosphorylation in leukemia stem cells, amplifying the therapeutic impact. Remarkably, clinical studies have revealed a favorable response, particularly in patients harboring specific mutations, such as , , , or . This prompts future studies to explore the nuanced underpinnings of these synergistic mechanisms in AML patients with these molecular signatures.
Topics: Humans; Bridged Bicyclo Compounds, Heterocyclic; Sulfonamides; Down-Regulation; Azacitidine; Myeloproliferative Disorders; Leukemia, Myeloid, Acute
PubMed: 38203655
DOI: 10.3390/ijms25010484 -
Therapeutic Advances in Hematology 2023Decitabine, a member of the 5-azanucleosides, has a dose-dependent mechanism of action : termination of DNA replication at high doses, and inhibition of DNA... (Review)
Review
Decitabine, a member of the 5-azanucleosides, has a dose-dependent mechanism of action : termination of DNA replication at high doses, and inhibition of DNA methyltransferase at low doses. The alteration of DNA methylation patterns by low-dose decitabine is hypothesized to upregulate genes, which promote myeloblast differentiation. In a phase III clinical trial, low-dose decitabine achieved a superior overall response rate (ORR) when compared with 'treatment choice' [consisting of low-dose cytarabine (80%) and supportive care (20%)] as a frontline treatment for elderly patients with acute myeloid leukemia (AML). Despite an improved ORR, the median overall survival (OS) for elderly patients with AML was poor, <1 year. In turn, venetoclax was added to low-dose decitabine, the combination of which significantly improved the ORR and median OS in elderly patients with AML. Currently, hypomethylating agents are being combined with other novel therapies as investigational strategies for elderly and unfit patients with AML. They are also being evaluated as components of maintenance therapy in patients achieving remission. An oral formulation of decitabine has been developed which relies on the concomitant use of oral cedazuridine to protect against first pass metabolism. This oral formulation, which has been approved in myelodysplastic syndrome, is intended to increase convenience of use and therefore compliance in patients. This review characterizes the evolution of decitabine, its oral formulation, and its future in the treatment of AML.
PubMed: 37854355
DOI: 10.1177/20406207231205429 -
Clinical Hematology International 2023Higher-risk Myelodysplastic Syndromes/Neoplasms (MDS) represent an ongoing therapeutic challenge, with few effective therapies, many of which may have limited use in...
Higher-risk Myelodysplastic Syndromes/Neoplasms (MDS) represent an ongoing therapeutic challenge, with few effective therapies, many of which may have limited use in this older patient population often with considerations around comorbidities. Outside of transplant, azacitidine and decitabine remain the only disease-modifying therapies, and are palliative in nature. Recent interest has grown in extending combination chemotherapies used to treat acute myeloid leukemia (AML) to patients with MDS, including novel combination chemotherapy "doublets" and "triplets." In this review, we discuss considerations around combination chemotherapy in MDS, specifically as relates to study design, appropriate endpoints, supportive considerations, and how to integrate these into the current treatment paradigm. New therapies in MDS are desperately needed but also require considerations particular to this unique patient population.
PubMed: 37933301
DOI: 10.46989/001c.88301 -
NPJ Breast Cancer Aug 2023TROP2 antibody drug conjugates (ADCs) are under active development. We seek to determine whether we can enhance activity of TROP2 ADCs by increasing TROP2 expression. In...
TROP2 antibody drug conjugates (ADCs) are under active development. We seek to determine whether we can enhance activity of TROP2 ADCs by increasing TROP2 expression. In metaplastic breast cancers (MpBC), there is limited expression of TROP2, and downregulating transcription factor ZEB1 upregulates E-cad and TROP2, thus sensitizing cancers to TROP2 ADC sacituzumab govitecan (SG). Demethylating agent decitabine decreases DNA methyltransferase expression and TROP2 promoter methylation and subsequently increases TROP2 expression. Decitabine treatment as well as overexpression of TROP2 significantly enhance SG antitumor activity. Decitabine also increases SLFN11, a biomarker of topoisomerase 1 inhibitor (TOP1) sensitivity and is synergistic with SG which has a TOP1 payload, in TROP2-expressing SLFN11-low BC cells. In conclusion, TROP2 and SLFN11 expression can be epigenetically modulated and the combination of demethylating agent decitabine with TROP2 ADCs may represent a novel therapeutic approach for tumors with low TROP2 or SLFN11 expression.
PubMed: 37567892
DOI: 10.1038/s41523-023-00573-8 -
Cell Reports Sep 2023Decitabine (DAC) is clinically used to treat myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). Our genome-wide CRISPR-dCas9 activation screen using...
Decitabine (DAC) is clinically used to treat myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). Our genome-wide CRISPR-dCas9 activation screen using MDS-derived AML cells indicates that mitotic regulation is critical for DAC resistance. DAC strongly induces abnormal mitosis (abscission failure or tripolar mitosis) in human myeloid tumors at clinical concentrations, especially in those with TP53 mutations or antecedent hematological disorders. This DAC-induced mitotic disruption and apoptosis are significantly attenuated in DNMT1-depleted cells. In contrast, overexpression of Dnmt1, but not the catalytically inactive mutant, enhances DAC-induced mitotic defects in myeloid tumors. We also demonstrate that DAC-induced mitotic disruption is enhanced by pharmacological inhibition of the ATR-CLSPN-CHK1 pathway. These data challenge the current assumption that DAC inhibits leukemogenesis through DNMT1 inhibition and subsequent DNA hypomethylation and highlight the potent activity of DAC to disrupt mitosis through aberrant DNMT1-DNA covalent bonds.
Topics: Humans; Decitabine; Azacitidine; Antimetabolites, Antineoplastic; Leukemia, Myeloid, Acute; DNA Methylation; DNA; Adaptor Proteins, Signal Transducing
PubMed: 37714156
DOI: 10.1016/j.celrep.2023.113098 -
Cell Reports Aug 2023Small cell lung cancers (SCLCs) rapidly resist cytotoxic chemotherapy and immune checkpoint inhibitor (ICI) treatments. New, non-cross-resistant therapies are thus...
Small cell lung cancers (SCLCs) rapidly resist cytotoxic chemotherapy and immune checkpoint inhibitor (ICI) treatments. New, non-cross-resistant therapies are thus needed. SCLC cells are committed into neuroendocrine lineage then maturation arrested. Implicating DNA methyltransferase 1 (DNMT1) in the maturation arrests, we find (1) the repression mark methylated CpG, written by DNMT1, is retained at suppressed neuroendocrine-lineage genes, even as other repression marks are erased; (2) DNMT1 is recurrently amplified, whereas Ten-Eleven-Translocation 2 (TET2), which functionally opposes DNMT1, is deleted; (3) DNMT1 is recruited into neuroendocrine-lineage master transcription factor (ASCL1, NEUROD1) hubs in SCLC cells; and (4) DNMT1 knockdown activated ASCL1-target genes and released SCLC cell-cycling exits by terminal lineage maturation, which are cycling exits that do not require the p53/apoptosis pathway used by cytotoxic chemotherapy. Inhibiting DNMT1/corepressors with clinical compounds accordingly extended survival of mice with chemorefractory and ICI-refractory, p53-null, disseminated SCLC. Lineage commitment of SCLC cells can hence be leveraged into non-cytotoxic therapy able to treat chemo/ICI-refractory SCLC.
Topics: Animals; Mice; Tumor Suppressor Protein p53; Small Cell Lung Carcinoma; Cell Cycle; Cell Division; Lung Neoplasms
PubMed: 37597186
DOI: 10.1016/j.celrep.2023.113016 -
Cancers Sep 2023is the most commonly mutated gene in human cancers and was the first tumor suppressor gene to be discovered in the history of medical science. Mutations in the gene... (Review)
Review
INTRODUCTION
is the most commonly mutated gene in human cancers and was the first tumor suppressor gene to be discovered in the history of medical science. Mutations in the gene occur at various genetic locations and exhibit significant heterogeneity among patients. Mutations occurring primarily within the DNA-binding domain of result in the loss of the p53 protein's DNA-binding capability. However, a complex phenotypic landscape often combines gain-of-function, dominant negative, or altered specificity features. This complexity poses a significant challenge in developing an effective treatment strategy, which eradicates -mutated cancer clones. This review summarizes the current understanding of mutations in AML and their implications. mutation in AML: In patients with acute myeloid leukemia (AML), six hotspot mutations (R175H, G245S, R248Q/W, R249S, R273H/S, and R282W) within the DNA-binding domain are common. mutations are frequently associated with a complex karyotype and subgroups of therapy-related or secondary AML. The presence of mutation is considered as a poor prognostic factor. -mutated AML is even classified as a distinct subgroup of AML by itself, as -mutated AML exhibits a significantly distinct landscape in terms of co-mutation and gene expression profiles compared with wildtype (WT)- AML.
CLINICAL IMPLICATIONS
To better predict the prognosis in cancer patients with different mutations, several predictive scoring systems have been proposed based on screening experiments, to assess the aggressiveness of -mutated cancer cells. Among those scoring systems, a relative fitness score (RFS) could be applied to AML patients with mutations in terms of overall survival (OS) and event-free survival (EFS). The current standard treatment, which includes cytotoxic chemotherapy and allogeneic hematopoietic stem cell transplantation, is largely ineffective for patients with -mutated AML. Consequently, most patients with -mutated AML succumb to leukemia within several months, despite active anticancer treatment. Decitabine, a hypomethylating agent, is known to be relatively effective in patients with AML. Numerous trials are ongoing to investigate the effects of novel drugs combined with hypomethylating agents, -targeting agents or immunologic agents.
CONCLUSIONS
Developing an effective treatment strategy for -mutated AML through innovative and multidisciplinary research is an urgent task. Directly targeting mutated holds promise as an approach to combating -mutated AML, and recent developments in immunologic agents for AML offer hope in this field.
PubMed: 37835510
DOI: 10.3390/cancers15194816 -
Clinical and Translational Medicine Jul 2023Energy balance has long been known to extend lifespans and inhibit carcinogenesis in multiple species by slowing age-related epigenetic changes while the underlying...
BACKGROUND
Energy balance has long been known to extend lifespans and inhibit carcinogenesis in multiple species by slowing age-related epigenetic changes while the underlying mechanisms remain largely unknown. Herein, we found that starvation activated autophagy to remodel the DNA methylation profile by inhibiting DNMT3a expression.
METHODS
Illumina Infinium MethylationEPIC BeadChip and dot blot assay were performed to quantify the global DNA methylation level. Protein-RNA interactions were validated through RNA immunoprecipitation and RNA pull-down assay. In vitro and in vivo experiments were carried out to testify the effect of DNMT3a on chemoresistance.
RESULTS
Autophagy is impaired in chemoresistance which was associated with differential DNA methylation and could be reversed by DNMT3a inhibition. Autophagy activation decreases the expression of DNMT3a mRNA, accompanied with the downregulation of chemoresistance-related Linc00942. Knockdown of Linc00942 reduces DNMT3a expression and genome-wide DNA methylation while Linc00942 overexpression increased DNMT3a expression and correlated hypermethylation in cancer cells and primary tumour tissues. Mechanistically, Linc00942 recruits RNA methyltransferase METTL3 to stimulate N6-methyladenosine (m6A) deposit on DNMT3a transcripts, triggering IGF2BP3/HuR to recognize modified mRNA for reinforced stability. SQSTM1/p62 recruits Linc00942 for autophagic degradation which can be abrogated after autophagy inhibition by p62 knockdown or chloroquine treatment.
CONCLUSIONS
Inhibition of autophagy increases Linc00942 expression to promote chemoresistance and autophagy activation or hypomethylating agent decitabine restores chemosensitivity by reducing global DNA methylation. Overall, this study identifies a novel methylation cascade linking impaired RNautophagy to global hypermethylation in chemoresistance, and provides a rationale for repurposing decitabine to overcome chemoresistance in cancer treatment.
Topics: Humans; DNA Methylation; Stomach Neoplasms; Drug Resistance, Neoplasm; Decitabine; RNA; RNA, Messenger; Methyltransferases
PubMed: 37477089
DOI: 10.1002/ctm2.1337