Prostaglandin E1 and Its Analog Misoprostol Inhibit Human CML Stem Cell Self-Renewal via EP4 Receptor Activation and Repression of AP-1

Identification of ubiquitination-related hub genes in chronic myeloid leukemia cell by bioinformatics analysis

Purpose: Chronic myeloid leukemia stem cells (CML-LSCs) are posited as the primary instigators of resistance to tyrosine kinase inhibitors (TKIs) and recurrence of CML. Ubiquitination, a post-translational modification, has been implicated in the worsening process of CML. A more detailed understanding of their crosstalk needs further investigation. Our research aims to explore the potential ubiquitination-related genes in CML-LSC using bioinformatics analysis that might be the target for the eradication of LSCs. Methods: The ubiquitination modification-related differentially expressed genes (UUC-DEGs) between normal hematopoietic stem cells (HSCs) and LSCs were obtained from GSE47927 and iUUCD database. Subsequently, the hub UUC-DEGs were identified through protein-protein interaction (PPI) network analysis utilizing the STRING database and the MCODE plug-in within the Cytoscape platform. The upstream regulation network of the hub UUC-DEGs was studied by hTFtarget, PROMO, miRDB and miRWalk databases respectively. Then the correlation between the hub UUC-DEGs and the immune cells was analyzed by the CIBERSORT algorithm and "ggcorrplot" package. Finally, we validated the function of hub UUC-DEGs in CML animal models, CML cell lines and CD34+ cells of the GSE24739 dataset. Results: There is a strong association between the 4 hub UUC genes (AURKA, Fancd2, Cdc20 and Uhrf1) of LSCs and the infiltration of CD4+/CD8+ T cells, NK cells and monocytes. 8 TFs and 23 miRNAs potentially targeted these 4 hub genes were constructed. Among these hub genes, Fancd2, Cdc20 and Uhrf1 were found to be highly expressed in CML-LSC, which knocking down resulted in significant inhibition of CML cell proliferation. Conclusions: From the perspective of bioinformatics analysis, UHRF1 and CDC20 were identified as the novel key ubiquitination-related genes in CML-LSCs and the pathogenesis of CML.

Cancer cell employs a microenvironmental neural signal trans-activating nucleus-mitochondria coordination to acquire stemness

Cancer cell receives extracellular signal inputs to obtain a stem-like status, yet how tumor microenvironmental (TME) neural signals steer cancer stemness to establish the hierarchical tumor architectures remains elusive. Here, a pan-cancer transcriptomic screening for 10852 samples of 33 TCGA cancer types reveals that cAMP-responsive element (CRE) transcription factors are convergent activators for cancer stemness. Deconvolution of transcriptomic profiles, specification of neural markers and illustration of norepinephrine dynamics uncover a bond between TME neural signals and cancer-cell CRE activity. Specifically, neural signal norepinephrine potentiates the stemness of proximal cancer cells by activating cAMP-CRE axis, where ATF1 serves as a conserved hub. Upon activation by norepinephrine, ATF1 potentiates cancer stemness by coordinated trans-activation of both nuclear pluripotency factors MYC/NANOG and mitochondrial biogenesis regulators NRF1/TFAM, thereby orchestrating nuclear reprograming and mitochondrial rejuvenating. Accordingly, single-cell transcriptomes confirm the coordinated activation of nuclear pluripotency with mitochondrial biogenesis in cancer stem-like cells. These findings elucidate that cancer cell acquires stemness via a norepinephrine-ATF1 driven nucleus-mitochondria collaborated program, suggesting a spatialized stemness acquisition by hijacking microenvironmental neural signals.

Critical Review on Fatty Acid-Based Food and Nutraceuticals as Supporting Therapy in Cancer

Fatty acids have an important place in both biological and nutritional contexts and, from a clinical point of view, they have known consequences for diseases’ onset and development, including cancer. The use of fatty acid-based food and nutraceuticals to support cancer therapy is a multidisciplinary subject, involving molecular and clinical research. Knowledge regarding polyunsaturated fatty acids essentiality/oxidizability and the role of lipogenesis-desaturase pathways for cell growth, as well as oxidative reactivity in cancer cells, are discussed, since they can drive the choice of fatty acids using their multiple roles to support antitumoral drug activity. The central role of membrane fatty acid composition is highlighted for the application of membrane lipid therapy. As fatty acids are also known as biomarkers of cancer onset and progression, the personalization of the fatty acid-based therapy is also possible, taking into account other important factors such as formulation, bioavailability and the distribution of the supplementation. A holistic approach emerges combining nutra- and pharma-strategies in an appropriate manner, to develop further knowledge and applications in cancer therapy.

TCF1 in T cell immunity: a broadened frontier

TCF1 and its homologue LEF1 are historically known as effector transcription factors downstream of the WNT signalling pathway and are essential for early T cell development. Recent advances bring TCF1 into the spotlight for its versatile, context-dependent functions in regulating mature T cell responses. In the cytotoxic T cell lineages, TCF1 is required for the self-renewal of stem-like CD8⁺ T cells generated in response to viral or tumour antigens, and for preserving heightened responses to checkpoint blockade immunotherapy. In the helper T cell lineages, TCF1 is indispensable for the differentiation of T follicular helper and T follicular regulatory cells, and crucially regulates immunosuppressive functions of regulatory T cells. Mechanistic investigations have also identified TCF1 as the first transcription factor that directly modifies histone acetylation, with the capacity to bridge transcriptional and epigenetic regulation. TCF1 also has the potential to become an important clinical biomarker for assessing the prognosis of tumour immunotherapy and the success of viral control in treating HIV and hepatitis C virus infection. Here, we summarize the key findings on TCF1 across the fields of T cell immunity and reflect on the possibility of exploring TCF1 and its downstream transcriptional programmes as therapeutic targets for improving antiviral and antitumour immunity.

Chronic myeloid leukemia stem cells: targeting therapeutic implications

Chronic myeloid leukemia (CML) is a clonal myeloproliferative neoplasm driven by BCR-ABL1 oncoprotein, which plays a pivotal role in CML pathology, diagnosis, and treatment as confirmed by the success of tyrosine kinase inhibitor (TKI) therapy. Despite advances in the development of more potent tyrosine kinase inhibitors, some mechanisms particularly in terms of CML leukemic stem cell (CML LSC) lead to intrinsic or acquired therapy resistance, relapse, and disease progression. In fact, the maintenance CML LSCs in patients who are resistance to TKI therapy indicates the role of CML LSCs in resistance to therapy through survival mechanisms that are not completely dependent on BCR-ABL activity. Targeting therapeutic approaches aim to eradicate CML LSCs through characterization and targeting genetic alteration and molecular pathways involving in CML LSC survival in a favorable leukemic microenvironment and resistance to apoptosis, with the hope of providing a functional cure. In other words, it is possible to develop the combination therapy of TKs with drugs targeting genes or molecules more specifically, which is required for survival mechanisms of CML LSCs, while sparing normal HSCs for clinical benefits along with TKIs.

Cancer Stem Cells: Metabolic Characterization for Targeted Cancer Therapy

The subpopulation of cancer stem cells (CSCs) within tumor bulk are known for tumor recurrence and metastasis. CSCs show intrinsic resistance to conventional therapies and phenotypic plasticity within the tumor, which make these a difficult target for conventional therapies. CSCs have different metabolic phenotypes based on their needs as compared to the bulk cancer cells. CSCs show metabolic plasticity and constantly alter their metabolic state between glycolysis and oxidative metabolism (OXPHOS) to adapt to scarcity of nutrients and therapeutic stress. The metabolic characteristics of CSCs are distinct compared to non-CSCs and thus provide an opportunity to devise more effective strategies to target CSCs. Mechanism for metabolic switch in CSCs is still unravelled, however existing evidence suggests that tumor microenvironment affects the metabolic phenotype of cancer cells. Understanding CSCs metabolism may help in discovering new and effective clinical targets to prevent cancer relapse and metastasis. This review summarises the current knowledge of CSCs metabolism and highlights the potential targeted treatment strategies.

Role of Lysophospholipid Metabolism in Chronic Myelogenous Leukemia Stem Cells

Simple Summary

In this review, I discuss our recent finding that lysophospholipid metabolism is essential for the maintenance of chronic myelogenous leukemia (CML) stem cells. Lysophospholipids have only one fatty acid chain and so are more hydrophilic than phospholipids, allowing them to act as lipid second messengers. We demonstrated that the stem cell quiescence and TKI resistance displayed by CML stem cells in vivo are sustained by the Gdpd3 enzyme involved in lysophospholipid metabolism. At the mechanistic level, Gdpd3 function allows lysophospholipid metabolism to suppress the AKT/mTORC1-mediated cell growth pathway while activating the stemness factors FOXO and β-catenin. Our results thus link lysophospholipid metabolism to CML stemness, and may thereby open up new therapeutic avenues to overcome CML relapse post-TKI therapy.

Abstract

It is well known that mature chronic myelogenous leukemia (CML) cells proliferate in response to oncogenic BCR–ABL1-dependent signaling, but how CML stem cells are able to survive in an oncogene-independent manner and cause disease relapse has long been elusive. Here, I put into the context of the broader literature our recent finding that lysophospholipid metabolism is essential for the maintenance of CML stem cells. I describe the fundamentals of lysophospholipid metabolism and discuss how one of its key enzymes, Glycerophosphodiester Phosphodiesterase Domain Containing 3 (Gdpd3), is responsible for maintaining the unique characteristics of CML stem cells. I also explore how this knowledge may be exploited to devise novel therapies for CML patients.

PGE1 triggers Nrf2/HO-1 signal pathway to resist hemin-induced toxicity in mouse cortical neurons

Background

Prostaglandin E1 (PGE1) exerts various pharmacological effects such as membrane stabilization, anti-inflammatory functions, vasodilation, and platelet aggregation inhibition. We have previously demonstrated that PGE1 has a beneficial impact on patients suffering from intracerebral hemorrhage (ICH). The related mechanism underlying PGE1’s beneficial effect on ICH treatment needs further exploration.

Methods

The present study elucidates the mechanism of PGE1 on ICH treatment using a neuronal apoptosis model in vitro. The mouse primary cortical neurons were pretreated with different concentrations of PGE1, followed by the treatment with hemin, the main catabolite in whole blood, to mimic the clinical ICH.

Results

Comparing with the vehicle-treated group, PGE1 prevented cultured cortical neurons from the accumulation of inhibited intracellular levels of reactive oxygen species (ROS), amelioration of mitochondrial membrane potential, and hemin-induced apoptosis. The reduction of ROS and apoptosis were associated with the up-regulation of Heme oxygenase-1 (HO-1) expression. Knockdown of nuclear transcription factor erythroid 2-related factor (Nrf2) by siRNA attenuated the upregulation of HO-1 as well as the protective effect of PGE1.

Conclusions

Our work suggests that the Nrf2/HO-1 molecular pathway may play a crucial role in treating ICH patients with PGE1 and may represent novel molecular targets, resulting in discovering new drugs for ICH treatment.

Dynamic Module Detection in Temporal Attributed Networks of cancers

Tracking the dynamic modules during cancer progression is essential for studying cancer pathogenesis, diagnosis and therapy. However, current algorithms only focus on detecting dynamic modules from temporal cancer networks without integrating the heterogeneous genomic data, thereby resulting in undesirable performance. To attack this issue, a novel algorithm (aka TANMF) is proposed to detect dynamic modules in cancer temporal attributed networks, which integrates the temporal networks and gene attributes. To obtain the dynamic modules, the temporality and gene attributed are incorporated into an overall objective function, which transforms the dynamic module detection into an optimization problem. TANMF jointly decomposes the snapshots at two subsequent time steps to obtain the latent features of dynamic modules, where the attributes are fused via regulations. Furthermore, L₁ constraint is imposed to improve the robustness. Experimental results demonstrate that TANMF is more accurate than state-of-the-art methods in terms of accuracy. By applying TANMF to breast cancer data, the obtained dynamic modules are more enriched by the known pathways and associated with the survival time of patients. The proposed model and algorithm provide an effective way for the integrative analysis of heterogeneous omics.

New routes to eradicating chronic myelogenous leukemia stem cells by targeting metabolism

Chronic myelogenous leukemia (CML) stem cells are the cellular source of the vast majority of mature CML cells and responsible for relapse of CML disease post-tyrosine kinase inhibitor (TKI) therapy. Although mature CML cells, whose active division is driven by BCR-ABL1 oncogene-dependent signaling, are reduced by TKI therapy, CML stem cells are resistant because they become quiescent via a heretofore elusive mechanism that is independent of oncogene signaling. Recent advances in highly sensitive metabolomics analyses, however, have unveiled new metabolic pathways that are essential for the survival of CML stem cells. With respect to glucose metabolism, CML stem cells elevate anaplerosis to sustain the TCA cycle. Blast crisis (BC)-CML stem cells increase their branched-chained amino acid (BCAA) metabolism. Recently, we showed that CML stem cell quiescence in vivo is regulated by lysophospholipid metabolism that is specific to these cells, namely cooperation between the stemness factors FOXO and β-catenin. These findings reveal biologically significant links between CML stemness and novel metabolic mechanisms. In this review, I describe these links in the contexts of glucose, amino acid, and lipid metabolism, and speculate on how innovative therapeutics might be designed to eradicate CML stem cells in vivo and overcome disease relapse post-TKI therapy.

Targeting Abnormal Hematopoietic Stem Cells in Chronic Myeloid Leukemia and Philadelphia Chromosome-Negative Classical Myeloproliferative Neoplasms

Myeloproliferative neoplasms (MPNs) are unique hematopoietic stem cell disorders sharing mutations that constitutively activate the signal-transduction pathways involved in haematopoiesis. They are characterized by stem cell-derived clonal myeloproliferation. The key MPNs comprise chronic myeloid leukemia (CML), polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). CML is defined by the presence of the Philadelphia (Ph) chromosome and BCR-ABL1 fusion gene. Despite effective cytoreductive agents and targeted therapy, complete CML/MPN stem cell eradication is rarely achieved. In this review article, we discuss the novel agents and combination therapy that can potentially abnormal hematopoietic stem cells in CML and MPNs and the CML/MPN stem cell-sustaining bone marrow microenvironment.

Therapeutic strategies targeting somatic stem cells: Chemical approaches

Therapeutic modulation of fate and behavior of somatic stem cells can generate safe and functional cells ex vivo for cell-based therapy, or to repair and regenerate damaged tissues in vivo. Chemical approaches involving small molecules have provided promising approaches for modulating cellular fate and function. These strategies offer opportunities that support regenerative medicine. Here, we discuss strategies targeting somatic stem cells through chemical approaches, highlighting their progression as well as future prospects.

DYRK2 controls a key regulatory network in chronic myeloid leukemia stem cells

Chronic myeloid leukemia is a hematological cancer driven by the oncoprotein BCR-ABL1, and lifelong treatment with tyrosine kinase inhibitors extends patient survival to nearly the life expectancy of the general population. Despite advances in the development of more potent tyrosine kinase inhibitors to induce a durable deep molecular response, more than half of patients relapse upon treatment discontinuation. This clinical finding supports the paradigm that leukemia stem cells feed the neoplasm, resist tyrosine kinase inhibition, and reactivate upon drug withdrawal depending on the fitness of the patient's immune surveillance. This concept lends support to the idea that treatment-free remission is not achieved solely with tyrosine kinase inhibitors and that new molecular targets independent of BCR-ABL1 signaling are needed in order to develop adjuvant therapy to more efficiently eradicate the leukemia stem cell population responsible for chemoresistance and relapse. Future efforts must focus on the identification of new targets to support the discovery of potent and safe small molecules able to specifically eradicate the leukemic stem cell population. In this review, we briefly discuss molecular maintenance in leukemia stem cells in chronic myeloid leukemia and provide a more in-depth discussion of the dual-specificity kinase DYRK2, which has been identified as a novel actionable checkpoint in a critical leukemic network. DYRK2 controls the activation of p53 and proteasomal degradation of c-MYC, leading to impaired survival and self-renewal of leukemia stem cells; thus, pharmacological activation of DYRK2 as an adjuvant to standard therapy has the potential to induce treatment-free remission.

International Union of Basic and Clinical Pharmacology. CIX. Differences and Similarities between Human and Rodent Prostaglandin E2 Receptors (EP1-4) and Prostacyclin Receptor (IP): Specific Roles in Pathophysiologic Conditions

Prostaglandins are derived from arachidonic acid metabolism through cyclooxygenase activities. Among prostaglandins (PGs), prostacyclin (PGI2) and PGE2 are strongly involved in the regulation of homeostasis and main physiologic functions. In addition, the synthesis of these two prostaglandins is significantly increased during inflammation. PGI2 and PGE2 exert their biologic actions by binding to their respective receptors, namely prostacyclin receptor (IP) and prostaglandin E2 receptor (EP) 1-4, which belong to the family of G-protein-coupled receptors. IP and EP1-4 receptors are widely distributed in the body and thus play various physiologic and pathophysiologic roles. In this review, we discuss the recent advances in studies using pharmacological approaches, genetically modified animals, and genome-wide association studies regarding the roles of IP and EP1-4 receptors in the immune, cardiovascular, nervous, gastrointestinal, respiratory, genitourinary, and musculoskeletal systems. In particular, we highlight similarities and differences between human and rodents in terms of the specific roles of IP and EP1-4 receptors and their downstream signaling pathways, functions, and activities for each biologic system. We also highlight the potential novel therapeutic benefit of targeting IP and EP1-4 receptors in several diseases based on the scientific advances, animal models, and human studies. SIGNIFICANCE STATEMENT: In this review, we present an update of the pathophysiologic role of the prostacyclin receptor, prostaglandin E2 receptor (EP) 1, EP2, EP3, and EP4 receptors when activated by the two main prostaglandins, namely prostacyclin and prostaglandin E2, produced during inflammatory conditions in human and rodents. In addition, this comparison of the published results in each tissue and/or pathology should facilitate the choice of the most appropriate model for the future studies.

The lysophospholipase D enzyme Gdpd3 is required to maintain chronic myelogenous leukaemia stem cells

Although advanced lipidomics technology facilitates quantitation of intracellular lipid components, little is known about the regulation of lipid metabolism in cancer cells. Here, we show that disruption of the Gdpd3 gene encoding a lysophospholipase D enzyme significantly decreased self-renewal capacity in murine chronic myelogenous leukaemia (CML) stem cells in vivo. Sophisticated lipidomics analyses revealed that Gdpd3 deficiency reduced levels of certain lysophosphatidic acids (LPAs) and lipid mediators in CML cells. Loss of Gdpd3 also activated AKT/mTORC1 signalling and cell cycle progression while suppressing Foxo3a/β-catenin interaction within CML stem cell nuclei. Strikingly, CML stem cells carrying a hypomorphic mutation of Lgr4/Gpr48, which encodes a leucine-rich repeat (LRR)-containing G-protein coupled receptor (GPCR) acting downstream of Gdpd3, displayed inadequate disease-initiating capacity in vivo. Our data showing that lysophospholipid metabolism is required for CML stem cell maintenance in vivo establish a new, biologically significant mechanism of cancer recurrence that is independent of oncogene addiction.

How lipid metabolism can affect cancer recurrence is still unclear. Here, the authors show that the lysophospholipase D Gdpd3 maintains self-renewal capacity of CML stem cells by regulating the quiescence, and AKT/mTORC1 and Foxo3a/β-catenin signalling in an oncogene-independent manner.

β-catenin and γ-catenin are dispensable for T lymphocytes and AML leukemic stem cells

The β-catenin transcriptional coregulator is involved in various biological and pathological processes; however, its requirements in hematopoietic cells remain controversial. We re-targeted the Ctnnb1 gene locus to generate a true β-catenin-null mutant mouse strain. Ablation of β-catenin alone, or in combination with its homologue γ-catenin, did not affect thymocyte maturation, survival or proliferation. Deficiency in β/γ-catenin did not detectably affect differentiation of CD4⁺T follicular helper cells or that of effector and memory CD8⁺ cytotoxic cells in response to acute viral infection. In an MLL-AF9 AML mouse model, genetic deletion of β-catenin, or even all four Tcf/Lef family transcription factors that interact with β-catenin, did not affect AML onset in primary recipients, or the ability of leukemic stem cells (LSCs) in propagating AML in secondary recipients. Our data thus clarify on a long-standing controversy and indicate that β-catenin is dispensable for T cells and AML LSCs.

Prostaglandin E1 prevents histopathological changes improving renal function in experimental nephropathy induced by renal microembolism

This study investigated the effect of prostaglandin E1 (PGE-1) treatment on the biochemical and histopathological changes in a model of nephropathy that was induced using renal microembolism in rats. Wistar rats were assigned to three groups: a control group (C, normal), a renal microembolism (RM) group, and a renal microembolism treated with PGE-1 (RM + PGE-1) group. The renal microembolism was induced by an arterial injection of polymethylmethacrylate microbeads into the remaining kidney of nephrectomized rats. Intramuscular treatment with PGE-1 was initiated on the day of the induction of the renal microembolism and continued once weekly for up to 60 days. At the end of the treatment period, blood samples were taken to assess the serum creatinine and urea concentrations, and 24-h urine samples were collected to determine the total protein levels. The rats' kidneys were removed and processed for histopathological analysis using the hematoxylin and eosin, periodic acid-Schiff, Mallory-Azan, and Picro-Sirius techniques. An immunohistochemical assay with vascular endothelial growth factor receptor-2 (anti-VEGFR-2) was also performed. The results showed that the PGE-1 treatment prevented vascular, glomerular, tubular, and interstitial alterations and reduced the biochemical changes, thus improving the renal function in rats that were subjected to renal microembolism. These effects could be partially attributable to an increase in the PGE-1-induced angiogenesis, because we observed an increase in the tissue expression of VEGFR-2, a specific marker of angiogenesis.

ARS2/MAGL signaling in glioblastoma stem cells promotes self-renewal and M2-like polarization of tumor-associated macrophages

The interplay between glioblastoma stem cells (GSCs) and tumor-associated macrophages (TAMs) promotes progression of glioblastoma multiforme (GBM). However, the detailed molecular mechanisms underlying the relationship between these two cell types remain unclear. Here, we demonstrate that ARS2 (arsenite-resistance protein 2), a zinc finger protein that is essential for early mammalian development, plays critical roles in GSC maintenance and M2-like TAM polarization. ARS2 directly activates its novel transcriptional target MGLL, encoding monoacylglycerol lipase (MAGL), to regulate the self-renewal and tumorigenicity of GSCs through production of prostaglandin E₂ (PGE₂), which stimulates β-catenin activation of GSC and M2-like TAM polarization. We identify M2-like signature downregulated by which MAGL-specific inhibitor, JZL184, increased survival rate significantly in the mouse xenograft model by blocking PGE₂ production. Taken together, our results suggest that blocking the interplay between GSCs and TAMs by targeting ARS2/MAGL signaling offers a potentially novel therapeutic option for GBM patients.

Repositioning Aspirin to Treat Lung and Breast Cancers and Overcome Acquired Resistance to Targeted Therapy

Background: The major limitation of targeted cancer therapy is development of acquired resistance. Intratumoral heterogeneity and coexist of multiple resistance mechanisms make combination therapies targeting one specific mechanism inefficient.

Methods: Transcriptional signature obtained from GEO was used to reposition FDA-approved drugs to treat lung and breast cancers as well as overcome acquired resistance to EGFR TKIs in lung cancer and to tamoxifen in breast cancer via CMap. In vitro and in vivo models were used to examine candidate drugs for their anti-cancer and anti-resistance efficacy and underlying mechanisms.

Results: We found that aspirin, the most commonly used drug, not only inhibited proliferation and promoted apoptosis of cancer cells, but also delayed and overcame acquired resistance to targeted therapy using in vitro and in vivo models. The underlying mechanism could be attributed to enhanced cancer stemness and activated NF-κB signaling in acquired resistant tumors, both of which were suppressed by aspirin and rendered resistant tumors more sensitive to aspirin.

Conclusions: Our data identify aspirin as a potential candidate for combination therapy for lung and breast cancers.

A KLF4-DYRK2-mediated pathway regulating self-renewal in CML stem cells

Leukemia stem cells are a rare population with a primitive progenitor phenotype that can initiate, sustain, and recapitulate leukemia through a poorly understood mechanism of self-renewal. Here, we report that Krüppel-like factor 4 (KLF4) promotes disease progression in a murine model of chronic myeloid leukemia (CML)-like myeloproliferative neoplasia by repressing an inhibitory mechanism of preservation in leukemia stem/progenitor cells with leukemia-initiating capacity. Deletion of the Klf4 gene severely abrogated the maintenance of BCR-ABL1(p210)-induced CML by impairing survival and self-renewal in BCR-ABL1+ CD150+ lineage-negative Sca-1+ c-Kit+ leukemic cells. Mechanistically, KLF4 repressed the Dyrk2 gene in leukemic stem/progenitor cells; thus, loss of KLF4 resulted in elevated levels of dual-specificity tyrosine-(Y)-phosphorylation-regulated kinase 2 (DYRK2), which were associated with inhibition of survival and self-renewal via depletion of c-Myc protein and p53 activation. In addition to transcriptional regulation, stabilization of DYRK2 protein by inhibiting ubiquitin E3 ligase SIAH2 with vitamin K3 promoted apoptosis and abrogated self-renewal in murine and human CML stem/progenitor cells. Altogether, our results suggest that DYRK2 is a molecular checkpoint controlling p53- and c-Myc-mediated regulation of survival and self-renewal in CML cells with leukemic-initiating capacity that can be targeted with small molecules.

Nephropathy induced by renal microembolism: a characterization of biochemical and histopathological changes in rats

The aim of this study was to investigate some biochemical parameters of renal function and the vascular, glomerular, tubular, and interstitial manifestations in the progression of nephropathy induced by renal microembolism. Renal microembolism was induced by the arterial injection of polymethacrylate microspheres in the remnant kidney of nephrectomized rats. Animals 110-120 days old were randomly divided into three groups: the control group (C; normal), the nephrectomized group (S; nephrectomized that did not undergo renal microembolism), and the model group (M, nephrectomized animals that underwent renal arterial microembolism). The animals were evaluated 30, 60, and 90 days after the induction of a renal microembolism. Blood and urine samples were collected to determine serum creatinine (Cr) and urea (Ur) concentrations and urine total protein (Pt) concentrations. The kidneys were weighed and processed for histopathological analysis using hematoxylin and eosin (HE), periodic acid-Schiff (PAS), Mallory-Azan, and Picro-Sirius staining. The samples were also subjected to immunohistochemistry with a proliferating cell nuclear antigen (PCNA) and a vascular endothelial growth factor receptor (VEGFR). The data demonstrated evidence of the occurrence of vascular, glomerular, tubular, and interstitial abnormalities in the renal tissue, and changes in the biochemical parameters of renal function (serum Cr and Ur and of 24-h urine Pt) in this experimental model of nephropathy induced by renal microembolism, which may indicate the development of chronic kidney disease (CKD). Additionally, the findings indicate that this is a good reproducibility model that may be useful for studying the pathogenesis of CKD that is caused by atheroembolism and possible treatment alternatives.

Chronic myeloid leukemia stem cells

Chronic myeloid leukemia (CML) is caused by BCRABL1 in a cell with the biological potential, intrinsic or acquired, to cause leukemia. This cell is commonly termed the CML leukemia stem cell (LSC). In humans a CML LSC is operationally-defined by ≥1 in vitro or in vivo assays of human leukemia cells transferred to immune-deficient mice. Results of these assays are sometimes discordant. There is also the unproved assumption that biological features of a CML LSC are stable. These considerations make accurate and precise identification of a CML LSC difficult or impossible. In this review, we consider biological features of CML LSCs defined by these assays. We also consider whether CML LSCs are susceptible to targeting by tyrosine kinase inhibitors (TKIs) and other drugs, and whether elimination of CML LSCs is needed to achieve therapy-free remission or cure CML.

Monitoring and Analysis of Chinese Chronic Myeloid Leukemia Patients Who Have Stopped Tyrosine Kinase Inhibitor Therapy

Discontinuation of tyrosine kinase inhibitor (TKI) therapy after achieving a persistent deep molecular response (DMR) is an urgently needed treatment goal for chronic myeloid leukemia (CML) patients and has been included in the National Comprehensive Cancer Network (NCCN) guidelines (version 2.2017) for CML. Indeed, various studies have confirmed the feasibility of discontinuing TKI therapy. In this study, we analyzed data from 45 CML patients who had discontinued TKI therapy. Univariate analysis was performed to predict factors that were potentially related to treatment-free remission (TFR) and identify the differences between early relapse and late relapse. Out of the 45 patients, 20 exhibited molecular relapse after a median follow-up of 18 months (range, 1-54 months), and the estimated TFR at 24 months was 40%. The univariate analysis revealed that a high Sokal score and interruptions or dose reductions during TKI treatment were the only baseline factors associated with poor outcomes. Our results indicate that TKI discontinuation could be successfully put into practice in China.

Metabolism-Based Therapeutic Strategies Targeting Cancer Stem Cells

Cancer heterogeneity constitutes the major source of disease progression and therapy failure. Tumors comprise functionally diverse subpopulations, with cancer stem cells (CSCs) as the source of this heterogeneity. Since these cells bear in vivo tumorigenicity and metastatic potential, survive chemotherapy and drive relapse, its elimination may be the only way to achieve long-term survival in patients. Thanks to the great advances in the field over the last few years, we know now that cellular metabolism and stemness are highly intertwined in normal development and cancer. Indeed, CSCs show distinct metabolic features as compared with their more differentiated progenies, though their dominant metabolic phenotype varies across tumor entities, patients and even subclones within a tumor. Following initial works focused on glucose metabolism, current studies have unveiled particularities of CSC metabolism in terms of redox state, lipid metabolism and use of alternative fuels, such as amino acids or ketone bodies. In this review, we describe the different metabolic phenotypes attributed to CSCs with special focus on metabolism-based therapeutic strategies tested in preclinical and clinical settings.

Metabolomics of neonatal blood spots reveal distinct phenotypes of pediatric acute lymphoblastic leukemia and potential effects of early-life nutrition

Early-life exposures are believed to influence the incidence of pediatric acute lymphoblastic leukemia (ALL). Archived neonatal blood spots (NBS), collected within the first days of life, offer a means to investigate small molecules that reflect early-life exposures. Using untargeted metabolomics, we compared abundances of small-molecule features in extracts of NBS punches from 332 children that later developed ALL and 324 healthy controls. Subjects were stratified by early (1-5 y) and late (6-14 y) diagnosis. Mutually-exclusive sets of metabolic features - representing putative lipids and fatty acids - were associated with ALL, including 9 and 19 metabolites in the early- and late-diagnosis groups, respectively. In the late-diagnosis group, a prominent cluster of features with apparent 18:2 fatty-acid chains suggested that newborn exposure to the essential nutrient, linoleic acid, increased ALL risk. Interestingly, abundances of these putative 18:2 lipids were greater in infants who were fed formula rather than breast milk (colostrum) and increased with the mother's pre-pregnancy body mass index. These results suggest possible etiologic roles of newborn nutrition in late-diagnosis ALL.

Ezh2 programs TFH differentiation by integrating phosphorylation-dependent activation of Bcl6 and polycomb-dependent repression of p19Arf

Ezh2 is an histone methyltransferase (HMT) that catalyzes H3K27me3 and functions in T_H1, T_H2, and Treg cells primarily via HMT activity. Here we show that Ezh2 ablation impairs T follicular helper (T_FH) cell differentiation and activation of the T_FH transcription program. In T_FH cells, most Ezh2-occupied genomic sites, including the Bcl6 promoter, are associated with H3K27ac rather than H3K27me3. Mechanistically, Ezh2 is recruited by Tcf1 to directly activate Bcl6 transcription, with this function requiring Ezh2 phosphorylation at Ser21. Meanwhile, Ezh2 deploys H3K27me3 to repress Cdkn2a expression in T_FH cells, where aberrantly upregulated p19Arf, a Cdkn2a protein product, triggers T_FH cell apoptosis and antagonizes Bcl6 function via protein-protein interaction. Either forced expression of Bcl6 or genetic ablation of p19Arf in Ezh2-deficient cells improves T_FH cell differentiation and helper function. Thus, Ezh2 orchestrates T_FH-lineage specification and function maturation by integrating phosphorylation-dependent transcriptional activation and HMT-dependent gene repression.

Ezh2 is an histone methyltransferase that catalyzes H3K27me3. Here the authors show that Ezh2 promotes T follicular helper (T_FH) differentiation and helper activity, by cooperating with Tcf1 to activate Bcl6 transcription and epigenetically repressing p19Arf, an antagonist of Bcl6 function and T_FH cell survival.

Regularized Multi-View Subspace Clustering for Common Modules Across Cancer Stages

Discovering the common modules that are co-expressed across various stages can lead to an improved understanding of the underlying molecular mechanisms of cancers. There is a shortage of efficient tools for integrative analysis of gene expression and protein interaction networks for discovering common modules associated with cancer progression. To address this issue, we propose a novel regularized multi-view subspace clustering (rMV-spc) algorithm to obtain a representation matrix for each stage and a joint representation matrix that balances the agreement across various stages. To avoid the heterogeneity of data, the protein interaction network is incorporated into the objective of rMV-spc via regularization. Based on the interior point algorithm, we solve the optimization problem to obtain the common modules. By using artificial networks, we demonstrate that the proposed algorithm outperforms state-of-the-art methods in terms of accuracy. Furthermore, the rMV-spc discovers common modules in breast cancer networks based on the breast data, and these modules serve as biomarkers to predict stages of breast cancer. The proposed model and algorithm effectively integrate heterogeneous data for dynamic modules.

Targeting chronic myeloid leukemia stem cells: can transcriptional program be a druggable target for cancers?

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm resulting from acquisition of constitutively active BCR-ABL protein tyrosine kinase in a hematopoietic stem cell (HSC). Though tyrosine kinase inhibitors (TKIs) have changed a fatal disease into manageable disease, most patients cannot discontinue TKI treatment due to persistence of TKI-resistant leukemia stem cells (LSCs). Much effort has been made to find out factors or pathways specifically operating in LSCs to selectively target LSCs, with some promising results at least in preclinical models. In this article, we briefly review the role of Wnt/β-catenin signaling and its related factors in CML LSCs, especially focusing on Tcf1/Lef1 transcription factors, major effectors of Wnt/β-catenin pathway, of which transcriptional program have recently been shown to be targetable with prostaglandin E1.

Stabilization of NF-κB-Inducing Kinase Suppresses MLL-AF9-Induced Acute Myeloid Leukemia

Canonical NF-κB signaling is constitutively activated in acute myeloid leukemia (AML) stem cells and is required for maintenance of the self-renewal of leukemia stem cells (LSCs). However, any potential role for NF-κB non-canonical signaling in AML has been largely overlooked. Here, we report that stabilization of NF-κB-inducing kinase (NIK) suppresses AML. Mechanistically, stabilization of NIK activates NF-κB non-canonical signaling and represses NF-κB canonical signaling. In addition, stabilization of NIK-induced activation of NF-κB non-canonical signaling upregulates Dnmt3a and downregulates Mef2c, which suppresses and promotes AML development, respectively. Importantly, by querying the connectivity MAP using up- and downregulated genes that are present exclusively in NIK-stabilized LSCs, we discovered that verteporfin has anti-AML effects, suggesting that repurposing verteporfin to target myeloid leukemia is worth testing clinically. Our data provide a scientific rationale for developing small molecules to stabilize NIK specifically in myeloid leukemias as an attractive therapeutic option.

Dihydroartemisinin-regulated mRNAs and lncRNAs in chronic myeloid leukemia

Chronic myelocytic leukemia (CML) is characterized by increased and unregulated growth of predominantly myeloid cells in the bone marrow, and accumulation of these cells in blood. We investigated the effects of an anti-malarial drug, dihydroartemisinin (DHA), on K562 CML cells. We identified 34 mRNAs and eight lncRNAs dysregulated following DHA treatment in pure and hemin-induced K562 cells. Up- or downregulation of these potential DHA targets increased with increasing DHA concentration. We also constructed and analyzed a DHA-related mRNA-lncRNA regulation network in K562 cells, and found that four DHA-modulated mRNAs regulated by four lncRNAs participated in the steroid biosynthesis pathway. Some estrogen-related drugs, such as tamoxifen, shared common targets with DHA. We inferred that DHA exerted anti-cancer effects on K562 cells by influencing estrogen levels. Our findings indicate that DHA has potential not only as an anti-malarial drug, but also as an anti-CML chemotherapeutic.