Evaluating ivosidenib for the treatment of acute myeloid leukemia

Epigenetic modifications in obesity-associated diseases

The global prevalence of obesity has reached epidemic levels, significantly elevating the susceptibility to various cardiometabolic conditions and certain types of cancer. In addition to causing metabolic abnormalities such as insulin resistance (IR), elevated blood glucose and lipids, and ectopic fat deposition, obesity can also damage pancreatic islet cells, endothelial cells, and cardiomyocytes through chronic inflammation, and even promote the development of a microenvironment conducive to cancer initiation. Improper dietary habits and lack of physical exercise are important behavioral factors that increase the risk of obesity, which can affect gene expression through epigenetic modifications. Epigenetic alterations can occur in early stage of obesity, some of which are reversible, while others persist over time and lead to obesity-related complications. Therefore, the dynamic adjustability of epigenetic modifications can be leveraged to reverse the development of obesity-associated diseases through behavioral interventions, drugs, and bariatric surgery. This review provides a comprehensive summary of the impact of epigenetic regulation on the initiation and development of obesity-associated cancers, type 2 diabetes, and cardiovascular diseases, establishing a theoretical basis for prevention, diagnosis, and treatment of these conditions.

Homodimer-mediated phosphorylation of C/EBPα-p42 S16 modulates acute myeloid leukaemia differentiation through liquid-liquid phase separation

CCAAT/enhancer binding protein α (C/EBPα) regulates myeloid differentiation, and its dysregulation contributes to acute myeloid leukaemia (AML) progress. Clarifying its functional implementation mechanism is of great significance for its further clinical application. Here, we show that C/EBPα regulates AML cell differentiation through liquid-liquid phase separation (LLPS), which can be disrupted by C/EBPα-p30. Considering that C/EBPα-p30 inhibits the functions of C/EBPα through the LZ region, a small peptide TAT-LZ that could instantaneously interfere with the homodimerization of C/EBPα-p42 was constructed, and dynamic inhibition of C/EBPα phase separation was observed, demonstrating the importance of C/EBPα-p42 homodimers for its LLPS. Mechanistically, homodimerization of C/EBPα-p42 mediated its phosphorylation at the novel phosphorylation site S16, which promoted LLPS and subsequent AML cell differentiation. Finally, decreasing the endogenous C/EBPα-p30/C/EBPα-p42 ratio rescued the phase separation of C/EBPα in AML cells, which provided a new insight for the treatment of the AML.

Isocitrate dehydrogenase 1 mutation drives leukemogenesis by PDGFRA activation due to insulator disruption in acute myeloid leukemia (AML)

Acute myeloid leukemia (AML) is characterized by complex molecular alterations and driver mutations. Elderly patients show increased frequencies of IDH mutations with high chemoresistance and relapse rates despite recent therapeutic advances. Besides being associated with global promoter hypermethylation, IDH1 mutation facilitated changes in 3D DNA-conformation by CTCF-anchor methylation and upregulated oncogene expression in glioma, correlating with poor prognosis. Here, we investigated the role of IDH1 p.R132H mutation in altering 3D DNA-architecture and subsequent oncogene activation in AML. Using public RNA-Seq data, we identified upregulation of tyrosine kinase PDGFRA in IDH1-mutant patients, correlating with poor prognosis. DNA methylation analysis identified CpG hypermethylation within a CTCF-anchor upstream of PDGFRA in IDH1-mutant patients. Increased PDGFRA expression, PDGFRA-CTCF methylation and decreased CTCF binding were confirmed in AML CRISPR cells with heterozygous IDH1 p.R132H mutation and upon exogenous 2-HG treatment. IDH1-mutant cells showed higher sensitivity to tyrosine kinase inhibitor dasatinib, which was supported by reduced blast count in a patient with refractory IDH1-mutant AML after dasatinib treatment. Our data illustrate that IDH1 p.R132H mutation leads to CTCF hypermethylation, disrupting DNA-looping and insulation of PDGFRA, resulting in PDGFRA upregulation in IDH1-mutant AML. Treatment with dasatinib may offer a novel treatment strategy for IDH1-mutant AML.

A concise review on the molecular genetics of acute myeloid leukemia

Acute myeloid leukemia (AML) is the most common acute leukemia in adults that affects the myeloid lineage. The recent advances have upgraded our understanding of the cytogenetic abnormalities and molecular mutations associated with AML that further aids in prognostication and risk stratification of the disease. Based on the highly heterogeneous nature of the disease and cytogenetic profile, AML patients can be stratified into favourable, intermediate and adverse-risk groups. The recurrent genetic alterations provide novel insights into the pathogenesis, clinical characteristics and also into the overall survival of the patients. In this review we are discussing about the cytogenetics of AML and the recurrent gene alterations such us NPM1, FLT3, CEBPA, TET-2, c-KIT, DNMT3A, IDH, RUNX1, AXSL1, WT1, Ras gene mutations etc. These gene mutations serve as important prognostic markers as well as potential therapeutic targets. AML patients respond to induction chemotherapy initially and subsequently achieve complete remission (CR), eventually most of them get relapsed.

Antileukemic Natural Product Induced Both Apoptotic and Pyroptotic Programmed Cell Death and Differentiation Effect

Acute myeloid leukemia (AML) is one of the most common forms of leukemia. Despite advances in the management of such malignancies and the progress of novel therapies, unmet medical needs still exist in AML because of several factors, including poor response to chemotherapy and high relapse rates. Ardisianone, a plant-derived natural component with an alkyl benzoquinone structure, induced apoptosis in leukemic HL-60 cells. The determination of dozens of apoptosis-related proteins showed that ardisianone upregulated death receptors and downregulated the inhibitor of apoptosis protein (IAPs). Western blotting showed that ardisianone induced a dramatic increase in tumor necrosis factor receptor 2 (TNFR2) protein expression. Ardisianone also induced downstream signaling by activating caspase-8 and -3 and degradation in Bid, a caspase-8 substrate. Furthermore, ardisianone induced degradation in DNA fragmentation factor 45 kDa (DFF45), a subunit of inhibitors of caspase-activated DNase (ICAD). Q-VD-OPh (a broad-spectrum caspase inhibitor) significantly diminished ardisianone-induced apoptosis, confirming the involvement of caspase-dependent apoptosis. Moreover, ardisianone induced pyroptosis. Using transmission electron microscopic examination and Western blot analysis, key markers including gasdermin D, high mobility group box1 (HMGB1), and caspase-1 and -5 were detected. Notably, ardisianone induced the differentiation of the remaining survival cells, which were characterized by an increase in the expression of CD11b and CD68, two markers of macrophages and monocytes. Wright–Giemsa staining also showed the differentiation of cells into monocyte and macrophage morphology. In conclusion, the data suggested that ardisianone induced the apoptosis and pyroptosis of leukemic cells through downregulation of IAPs and activation of caspase pathways that caused gasdermin D cleavage and DNA double-stranded breaks and ultimately led to programmed cell death. Ardisianone also induced the differentiation of leukemic cells into monocyte-like and macrophage-like cells. The data suggested the potential of ardisianone for further antileukemic development.

Efficacy and Safety Profile of Ivosidenib in the Management of Patients with Acute Myeloid Leukemia (AML): An Update on the Emerging Evidence

The isocitrate dehydrogenase enzyme, catalyzing isocitrate conversion to α-ketoglutarate (αKG) in both the cell cytoplasm and mitochondria, contributes to the production of dihydronicotinamide-adenine dinucleotide phosphate (NADPH) as a reductive potential in various cellular processes. IDH1 gene mutations are revealed in up to 20% of the patients with acute myeloid leukemia (AML). A mutant IDH enzyme, existing in the cell cytoplasm and possessing neomorphic activity, converts αKG into oncometabolite R-2-hydroxyglutarate (R-2-HG) that accumulates in high amounts in the cell and inhibits αKG-dependent enzymes, including epigenetic regulators. The resultant alteration in gene expression and blockade of differentiation ultimately lead to leukemia development. Myeloid differentiation capacity can be restored by obstruction of the mutant enzyme, inducing substantial reduction in R-2-HG levels. Ivosidenib, a potent selective inhibitor of mutant IDH1, is a differentiating agent shown to be clinically effective in newly diagnosed AML (ND-AML) and relapsed/refractory (R/R) AML harboring this mutation. The drug is approved by the Food and Drug Administration (FDA) as a single-agent treatment for R/R AML. Significance of mutated IDH1 targeting and a potential role of ivosidenib in AML management, when used either as a single agent or as part of combination therapies, will be reviewed herein.