CD69 partially inhibits apoptosis and erythroid differentiation via CD24, and their knockdown increase imatinib sensitivity in BCR-ABL-positive cells

Checkpoint CD24 function on tumor and immunotherapy

CD24 is a protein found on the surface of cells that plays a crucial role in the proliferation, invasion, and spread of cancer cells. It adheres to cell membranes through glycosylphosphatidylinositol (GPI) and is associated with the prognosis and survival rate of cancer patients. CD24 interacts with the inhibitory receptor Siglec-10 that is present on immune cells like natural killer cells and macrophages, leading to the inhibition of natural killer cell cytotoxicity and macrophage-mediated phagocytosis. This interaction helps tumor cells escape immune detection and attack. Although the use of CD24 as a immune checkpoint receptor target for cancer immunotherapy is still in its early stages, clinical trials have shown promising results. Monoclonal antibodies targeting CD24 have been found to be well-tolerated and safe. Other preclinical studies are exploring the use of chimeric antigen receptor (CAR) T cells, antibody-drug conjugates, and gene therapy to target CD24 and enhance the immune response against tumors. In summary, this review focuses on the role of CD24 in the immune system and provides evidence for CD24 as a promising immune checkpoint for cancer immunotherapy.

Endothelial Cell Response in Kawasaki Disease and Multisystem Inflammatory Syndrome in Children

Although Kawasaki disease (KD) and multisystem inflammatory syndrome in children (MIS-C) share some clinical manifestations, their cardiovascular outcomes are different, and this may be reflected at the level of the endothelial cell (EC). We performed RNA-seq on cultured ECs incubated with pre-treatment sera from KD (n = 5), MIS-C (n = 7), and healthy controls (n = 3). We conducted a weighted gene co-expression network analysis (WGCNA) using 935 transcripts differentially expressed between MIS-C and KD using relaxed filtering (unadjusted p < 0.05, >1.1-fold difference). We found seven gene modules in MIS-C, annotated as an increased TNFα/NFκB pathway, decreased EC homeostasis, anti-inflammation and immune response, translation, and glucocorticoid responsive genes and endothelial-mesenchymal transition (EndoMT). To further understand the difference in the EC response between MIS-C and KD, stringent filtering was applied to identify 41 differentially expressed genes (DEGs) between MIS-C and KD (adjusted p < 0.05, >2-fold-difference). Again, in MIS-C, NFκB pathway genes, including nine pro-survival genes, were upregulated. The expression levels were higher in the genes influencing autophagy (UBD, EBI3, and SQSTM1). Other DEGs also supported the finding by WGCNA. Compared to KD, ECs in MIS-C had increased pro-survival transcripts but reduced transcripts related to EndoMT and EC homeostasis. These differences in the EC response may influence the different cardiovascular outcomes in these two diseases.

Isolation, Maintenance and Expansion of Adult Hematopoietic Stem/Progenitor Cells and Leukemic Stem Cells

Simple Summary

Transplantation of adult hematopoietic stem cells is an important therapeutic tool to help patients suffering from diverse hematological disorders. All types of blood cells can develop from a single hematopoietic stem cell underlining their enormous potential. Intense efforts are ongoing to generate “engraftable” human hematopoietic stem cells to treat hematopoietic diseases and to understand the molecular machinery driving them. Leukemic stem cells represent a low frequency subpopulation of leukemia cells that possess stem cell properties. They can instigate, maintain, and serially propagate leukemia in vivo, while they retain the capacity to differentiate into committed progenitors. Leukemic stem cells are unaffected by many therapeutic strategies and represent the major cause of relapse. We here describe all methods to maintain and expand murine and human hematopoietic cells in culture and describe their specific advantages. These methods are also employed to understand the biology of leukemic stem cells and to identify novel therapeutic strategies.

Abstract

Hematopoietic stem cells (HSCs) are rare, self-renewing cells that perch on top of the hematopoietic tree. The HSCs ensure the constant supply of mature blood cells in a tightly regulated process producing peripheral blood cells. Intense efforts are ongoing to optimize HSC engraftment as therapeutic strategy to treat patients suffering from hematopoietic diseases. Preclinical research paves the way by developing methods to maintain, manipulate and expand HSCs ex vivo to understand their regulation and molecular make-up. The generation of a sufficient number of transplantable HSCs is the Holy Grail for clinical therapy. Leukemia stem cells (LSCs) are characterized by their acquired stem cell characteristics and are responsible for disease initiation, progression, and relapse. We summarize efforts, that have been undertaken to increase the number of long-term (LT)-HSCs and to prevent differentiation towards committed progenitors in ex vivo culture. We provide an overview and compare methods currently available to isolate, maintain and enrich HSC subsets, progenitors and LSCs and discuss their individual advantages and drawbacks.

Mutation accumulation in cancer genes relates to nonoptimal outcome in chronic myeloid leukemia

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm accounting for ∼15% of all leukemia. Progress of the disease from an indolent chronic phase to the more aggressive accelerated phase or blast phase (BP) occurs in a minority of cases and is associated with an accumulation of somatic mutations. We performed genetic profiling of 85 samples and transcriptome profiling of 12 samples from 59 CML patients. We identified recurrent somatic mutations in ABL1 (37%), ASXL1 (26%), RUNX1 (16%), and BCOR (16%) in the BP and observed that mutation signatures in the BP resembled those of acute myeloid leukemia (AML). We found that mutation load differed between the indolent and aggressive phases and that nonoptimal responders had more nonsilent mutations than did optimal responders at the time of diagnosis, as well as in follow-up. Using RNA sequencing, we identified other than BCR-ABL1 cancer-associated hybrid genes in 6 of the 7 BP samples. Uncovered expression alterations were in turn associated with mechanisms and pathways that could be targeted in CML management and by which somatic alterations may emerge in CML. Last, we showed the value of genetic data in CML management in a personalized medicine setting.

IL-33 promotes anemia during chronic inflammation by inhibiting differentiation of erythroid progenitors

An important comorbidity of chronic inflammation is anemia, which may be related to dysregulated activity of hematopoietic stem and progenitor cells (HSPCs) in the bone marrow (BM). Among HSPCs, we found that the receptor for IL-33, ST2, is expressed preferentially and highly on erythroid progenitors. Induction of inflammatory spondyloarthritis in mice increased IL-33 in BM plasma, and IL-33 was required for inflammation-dependent suppression of erythropoiesis in BM. Conversely, administration of IL-33 in healthy mice suppressed erythropoiesis, decreased hemoglobin expression, and caused anemia. Using purified erythroid progenitors in vitro, we show that IL-33 directly inhibited terminal maturation. This effect was dependent on NF-κB activation and associated with altered signaling events downstream of the erythropoietin receptor. Accordingly, IL-33 also suppressed erythropoietin-accelerated erythropoiesis in vivo. These results reveal a role for IL-33 in pathogenesis of anemia during inflammatory disease and define a new target for its treatment.

8-Hydroxydaidzein, an Isoflavone from Fermented Soybean, Induces Autophagy, Apoptosis, Differentiation, and Degradation of Oncoprotein BCR-ABL in K562 Cells

8-Hydroxydaidzein (8-OHD, 7,8,4′-trihydoxyisoflavone) is a hydroxylated derivative of daidzein isolated from fermented soybean products. The aim of this study is to investigate the anti-proliferative effects and the underlying mechanisms of 8-OHD in K562 human chronic myeloid leukemia (CML) cells. We found that 8-OHD induced reactive oxygen species (ROS) overproduction and cell cycle arrest at the S phase by upregulating p21^Cip1 and downregulating cyclin D2 (CCND2) and cyclin-dependent kinase 6 (CDK6) expression. 8-OHD also induced autophagy, caspase-7-dependent apoptosis, and the degradation of BCR-ABL oncoprotein. 8-OHD promoted Early Growth Response 1 (EGR1)-mediated megakaryocytic differentiation as an increased expression of marker genes, CD61 and CD42b, and the formation of multi-lobulated nuclei in enlarged K562 cells. A microarray-based transcriptome analysis revealed a total of 3174 differentially expressed genes (DEGs) after 8-OHD (100 μM) treatment for 48 h. Bioinformatics analysis of DEGs showed that hemopoiesis, cell cycle regulation, nuclear factor-κB (NF-κB), and mitogen-activated protein kinase (MAPK) and Janus kinase/signal transducers and activators of transcription (JAK-STAT)-mediated apoptosis/anti-apoptosis networks were significantly regulated by 8-OHD. Western blot analysis confirmed that 8-OHD significantly induced the activation of MAPK and NF-κB signaling pathways, both of which may be responsible, at least in part, for the stimulation of apoptosis, autophagy, and differentiation in K562 cells. This is the first report on the anti-CML effects of 8-OHD and the combination of experimental and in silico analyses could provide a better understanding for the development of 8-OHD on CML therapy.

p19INK4d inhibits proliferation and enhances imatinib efficacy through BCR-ABL signaling pathway in chronic myeloid leukemia

Chronic myeloid leukemia (CML) is a kind of myeloproliferative disorder caused by a constitutively active BCR-ABL tyrosine kinase. Tyrosine kinase inhibitors (TKIs), imatinib and its derivatives, have achieved great progress in the treatment of CML. However, many CML patients do not respond to TKIs alone. p19^INK4d, a cyclin-dependent kinase inhibitor, plays important roles in proliferation, DNA damage repair, apoptosis and cell differentiation, but its role in CML is unknown. Herein, we found that the expression of p19^INK4d in CML patients was significantly lower than that in healthy controls. p19^INK4d overexpression inhibits cell proliferation through cell cycle arrest, and cooperates with imatinib to inhibit CML more effectively in vitro and in vivo. Mechanistically, p19^INK4d decreased the expression of BCR-ABL and its downstream molecules p-Mek1/2, moreover, the expression of Gli-1, c-myc, MUC1, Shh and TC48 also reduced significantly. Collectively, p19^INK4d inhibits proliferation and enhances imatinib efficacy in the treatment of CML. These findings maybe have implications for developing potential targets to increase imatinib sensitivity for CML.