Zeb1 modulates hematopoietic stem cell fates required for suppressing acute myeloid leukemia

Zeb1 maintains long-term adult hematopoietic stem cell function and extramedullary hematopoiesis

Emerging evidence implicates the epithelial-mesenchymal transition transcription factor Zeb1 as a critical regulator of hematopoietic stem cell (HSC) differentiation. Whether Zeb1 regulates long-term maintenance of HSC function remains an open question. Using an inducible Mx-1-Cre mouse model that deletes conditional Zeb1 alleles in the adult hematopoietic system, we found that mice engineered to be deficient in Zeb1 for 32 weeks displayed expanded immunophenotypically defined adult HSCs and multipotent progenitors associated with increased abundance of lineage-biased/balanced HSC subsets and augmented cell survival characteristics. During hematopoietic differentiation, persistent Zeb1 loss increased B cells in the bone marrow and spleen and decreased monocyte generation in the peripheral blood. In competitive transplantation experiments, we found that HSCs from adult mice with long-term Zeb1 deletion displayed a cell autonomous defect in multilineage differentiation capacity. Long-term Zeb1 loss perturbed extramedullary hematopoiesis characterized by increased splenic weight and a paradoxical reduction in splenic cellularity that was accompanied by HSC exhaustion, lineage-specific defects, and an accumulation of aberrant, preleukemic like c-kit+CD16/32+ progenitors. Loss of Zeb1 for up to 42 weeks can lead to progressive splenomegaly and an accumulation of Gr-1+Mac-1+ cells, further supporting the notion that long-term expression of Zeb1 suppresses preleukemic activity. Thus, sustained Zeb1 deletion disrupts HSC functionality in vivo and impairs regulation of extramedullary hematopoiesis with potential implications for tumor suppressor functions of Zeb1 in myeloid neoplasms.

Corneal injury repair and the potential involvement of ZEB1

The cornea, consisting of three cellular and two non-cellular layers, is the outermost part of the eyeball and frequently injured by external physical, chemical, and microbial insults. The epithelial-to-mesenchymal transition (EMT) plays a crucial role in the repair of corneal injuries. Zinc finger E-box binding homeobox 1 (ZEB1), an important transcription factor involved in EMT, is expressed in the corneal tissues. It regulates cell activities like migration, transformation, and proliferation, and thereby affects tissue inflammation, fibrosis, tumor metastasis, and necrosis by mediating various major signaling pathways, including transforming growth factor (TGF)-β. Dysfunction of ZEB1 would impair corneal tissue repair leading to epithelial healing delay, interstitial fibrosis, neovascularization, and squamous cell metaplasia. Understanding the mechanism underlying ZEB1 regulation of corneal injury repair will help us to formulate a therapeutic approach to enhance corneal injury repair.

Conditional deletion of Zeb1 in Csf1r+ cells reduces inflammatory response of the cornea to alkali burn

ZEB1 is an essential factor in embryonic development. In adults, it is often highly expressed in malignant tumors with low expression in normal tissues. The major biological function of ZEB1 in developing embryos and progressing cancers is to transdifferentiate cells from an epithelial to mesenchymal phenotype; but what roles ZEB1 plays in normal adult tissues are largely unknown. We previously reported that the reduction of Zeb1 in monoallelic global knockout (Zeb1+/-) mice reduced corneal inflammation-associated neovascularization following alkali burn. To uncover the cellular mechanism underlying the Zeb1 regulation of corneal inflammation, we functionally deleted Zeb1 alleles in Csf1r+ myeloid cells using a conditional knockout (cKO) strategy and found that Zeb1 cKO reduced leukocytes in the cornea after alkali burn. The reduction of immune cells was due to their increased apoptotic rate and linked to a Zeb1-downregulated apoptotic pathway. We conclude that Zeb1 facilitates corneal inflammatory response by maintaining Csf1r+ cell viability.

ZEB1 shapes AML immunological niches, suppressing CD8 T cell activity while fostering Th17 cell expansion

Acute myeloid leukemia (AML) progression is influenced by immune suppression induced by leukemia cells. ZEB1, a critical transcription factor in epithelial-to-mesenchymal transition, demonstrates immune regulatory functions in AML. Silencing ZEB1 in leukemic cells reduces engraftment and extramedullary disease in immune-competent mice, activating CD8 T lymphocytes and limiting Th17 cell expansion. ZEB1 in AML cells directly promotes Th17 cell development that, in turn, creates a self-sustaining loop and a pro-invasive phenotype, favoring transforming growth factor β (TGF-β), interleukin-23 (IL-23), and SOCS2 gene transcription. In bone marrow biopsies from AML patients, immunohistochemistry shows a direct correlation between ZEB1 and Th17. Also, the analysis of ZEB1 expression in larger datasets identifies two distinct AML groups, ZEB1high and ZEB1low, each with specific immunological and molecular traits. ZEB1high patients exhibit increased IL-17, SOCS2, and TGF-β pathways and a negative association with overall survival. This unveils ZEB1's dual role in AML, entwining pro-tumoral and immune regulatory capacities in AML blasts.

Integrative single-cell expression and functional studies unravels a sensitization to cytarabine-based chemotherapy through HIF pathway inhibition in AML leukemia stem cells

Relapse remains a major challenge in the clinical management of acute myeloid leukemia (AML) and is driven by rare therapy-resistant leukemia stem cells (LSCs) that reside in specific bone marrow niches. Hypoxia signaling maintains cells in a quiescent and metabolically relaxed state, desensitizing them to chemotherapy. This suggests the hypothesis that hypoxia contributes to the chemoresistance of AML-LSCs and may represent a therapeutic target to sensitize AML-LSCs to chemotherapy. Here, we identify HIFhigh and HIFlow specific AML subgroups (inv(16)/t(8;21) and MLLr, respectively) and provide a comprehensive single-cell expression atlas of 119,000 AML cells and AML-LSCs in paired diagnostic-relapse samples from these molecular subgroups. The HIF/hypoxia pathway signature is attenuated in AML-LSCs compared with more differentiated AML cells but is more expressed than in healthy hematopoietic cells. Importantly, chemical inhibition of HIF cooperates with standard-of-care chemotherapy to impair AML growth and to substantially eliminate AML-LSCs in vitro and in vivo. These findings support the HIF pathway in the stem cell-driven drug resistance of AML and unravel avenues for combinatorial targeted and chemotherapy-based approaches to specifically eliminate AML-LSCs.

Hypoxia inducible factor-1ɑ as a potential therapeutic target for osteosarcoma metastasis

Osteosarcoma (OS) is a malignant tumor originating from mesenchymal tissue. Pulmonary metastasis is usually present upon initial diagnosis, and metastasis is the primary factor affecting the poor prognosis of patients with OS. Current research shows that the ability to regulate the cellular microenvironment is essential for preventing the distant metastasis of OS, and anoxic microenvironments are important features of solid tumors. During hypoxia, hypoxia-inducible factor-1α (HIF-1α) expression levels and stability increase. Increased HIF-1α promotes tumor vascular remodeling, epithelial-mesenchymal transformation (EMT), and OS cells invasiveness; this leads to distant metastasis of OS cells. HIF-1α plays an essential role in the mechanisms of OS metastasis. In order to develop precise prognostic indicators and potential therapeutic targets for OS treatment, this review examines the molecular mechanisms of HIF-1α in the distant metastasis of OS cells; the signal transduction pathways mediated by HIF-1α are also discussed.

The landscape of SETBP1 gene expression and transcription factor activity across human tissues

The SET binding protein 1 (SETBP1) gene encodes a transcription factor (TF) involved in various cellular processes. Variants in SETBP1 can result in three different diseases determined by the introduction (germline vs. somatic) and location of the variant. Germline variants cause the ultra-rare pediatric Schinzel Giedion Syndrome (SGS) and SETBP1 haploinsufficiency disorder (SETBP1-HD), characterized by severe multisystemic abnormalities with neurodegeneration or a less severe brain phenotype accompanied by hypotonia and strabismus, respectively. Somatic variants in SETBP1 are associated with hematological malignancies and cancer development in other tissues in adults. To better understand the tissue-specific mechanisms involving SETBP1, we analyzed publicly available RNA-sequencing (RNA-seq) data from the Genotype-Tissue Expression (GTEx) project. We found SETBP1 and its known target genes were widely expressed across 31 adult human tissues. K-means clustering identified three distinct expression patterns of SETBP1 targets across tissues. Functional enrichment analysis (FEA) of each cluster revealed gene sets related to transcriptional regulation, DNA binding, and mitochondrial function. TF activity analysis of SETBP1 and its target TFs revealed tissue-specific TF activity, underscoring the role of tissue context-driven regulation and suggesting its impact in SETBP1-associated disease. In addition to uncovering tissue-specific molecular signatures of SETBP1 expression and TF activity, we provide a Shiny web application to facilitate exploring TF activity across human tissues for 758 TFs. This study provides insight into the landscape of SETBP1 expression and TF activity across 31 non-diseased human tissues and reveals tissue-specific expression and activity of SETBP1 and its targets. In conjunction with the web application we constructed, our framework enables researchers to generate hypotheses related to the role tissue backgrounds play with respect to gene expression and TF activity in different disease contexts.

Isolation of tumor stem-like cells from primary laryngeal squamous cell carcinoma cells (FD-LS-6)

The development of efficient treatments for laryngeal squamous cell carcinoma (LSCC) is hindered by the lack of applicable tumor cell lines and animal models of the disease, especially those related to cancer stem-like cells (CSCs). CSCs play critical roles in tumor propagation and pathogenesis whereas no CSCs lines have been developed to date. In this study, we establish an LSCC cell line (FD-LS-6) from primary LSCC tumor tissue (not experienced single-cell cloning) and adapted a culturing condition for the expansion of potential stem cells (EPSCs) to isolate CSCs from FD-LS-6. We successfully derived novel CSCs and named them as LSCC sphere-forming cells (LSCSCs) which were subsequently characterized for their CSC properties. We showed that LSCSCs shared many properties of CSCs, including CSC marker, robust self-renewal capacity, tumorigenesis ability, potential to generate other cell types such as adipocytes and osteoblasts, and resistance to chemotherapy. Compared to parental cells, LSCSCs were significantly more potent in forming tumors in vivo in mice and more resistant to chemotherapy. LSCSCs have higher expressions of epithelial-mesenchymal transition proteins and chemotherapy resistance factors, and exhibit an activated COX2/PEG2 signaling pathway. Altogether, our work establishes the first CSCs of LSCC (FD-LS-6) and provides a tool to study tumorigenesis and metastasis of LSCC and help the development of anticancer therapies.

Twist family BHLH transcription factor 1 is required for the maintenance of leukemia stem cell in MLL-AF9+ acute myeloid leukemia

Leukemia stem cells (LSC) are a rare population capable of limitless self-renewal and are responsible for the initiation, maintenance, and relapse of leukemia. Elucidation of the mechanisms underlying the regulation of LSC function could provide novel treatment strategies. Here, we show that TWIST1 is extremely highly expressed in the LSC of MLL-AF9+ acute myeloid leukemia (AML), and its upregulation is positively regulated by KDM4C in a H3K9me3 demethylation-dependent manner. We further demonstrate that TWIST1 is essential for the viability, dormancy, and self-renewal capacities of LSC, and that it promotes the initiation and maintenance of MLL-AF9-mediated AML. In addition, TWIST1 directly interacts and collaborates with HOXA9 in inducing AML in mice. Mechanistically, TWIST1 exerts its oncogenic function by activating the WNT5a/RAC1 axis. Collectively, our study uncovers a critical role of TWIST1 in LSC function and provides new mechanistic insights into the pathogenesis of MLL-AF9+ AML.

Expression of circular RNAs in myelodysplastic neoplasms and their association with mutations in the splicing factor gene SF3B1

Mutations in the splicing factor 3b subunit 1 (SF3B1) gene are frequent in myelodysplastic neoplasms (MDS). Because the splicing process is involved in the production of circular RNAs (circRNAs), we investigated the impact of SF3B1 mutations on circRNA processing. Using RNA sequencing, we measured circRNA expression in CD34+ bone marrow MDS cells. We defined circRNAs deregulated in a heterogeneous group of MDS patients and described increased circRNA formation in higher-risk MDS. We showed that the presence of SF3B1 mutations did not affect the global production of circRNAs; however, deregulation of specific circRNAs was observed. Particularly, we demonstrated that strong upregulation of circRNAs processed from the zinc finger E-box binding homeobox 1 (ZEB1) transcription factor; this upregulation was exclusive to SF3B1-mutated patients and was not observed in those with mutations in other splicing factors or other recurrently mutated genes, or with other clinical variables. Furthermore, we focused on the most upregulated ZEB1-circRNA, hsa_circ_0000228, and, by its knockdown, we demonstrated that its expression is related to mitochondrial activity. Using microRNA analyses, we proposed miR-1248 as a direct target of hsa_circ_0000228. To conclude, we demonstrated that mutated SF3B1 leads to deregulation of ZEB1-circRNAs, potentially contributing to the defects in mitochondrial metabolism observed in SF3B1-mutated MDS.

A Vaccine against Cancer: Can There Be a Possible Strategy to Face the Challenge? Possible Targets and Paradoxical Effects

Is it possible to have an available vaccine that eradicates cancer? Starting from this question, this article tries to verify the state of the art, proposing a different approach to the issue. The variety of cancers and different and often unknown causes of cancer impede, except in some cited cases, the creation of a classical vaccine directed at the causative agent. The efforts of the scientific community are oriented toward stimulating the immune systems of patients, thereby preventing immune evasion, and heightening chemotherapeutic agents effects against cancer. However, the results are not decisive, because without any warning signs, metastasis often occurs. The purpose of this paper is to elaborate on a vaccine that must be administered to a patient in order to prevent metastasis; metastasis is an event that leads to death, and thus, preventing it could transform cancer into a chronic disease. We underline the fact that the field has not been studied in depth, and that the complexity of metastatic processes should not be underestimated. Then, with the aim of identifying the target of a cancer vaccine, we draw attention to the presence of the paradoxical actions of different mechanisms, pathways, molecules, and immune and non-immune cells characteristic of the tumor microenvironment at the primary site and pre-metastatic niche in order to exclude possible vaccine candidates that have opposite effects/behaviors; after a meticulous evaluation, we propose possible targets to develop a metastasis-targeting vaccine. We conclude that a change in the current concept of a cancer vaccine is needed, and the efforts of the scientific community should be redirected toward a metastasis-targeting vaccine, with the increasing hope of eradicating cancer.

The landscape of SETBP1 gene expression and transcription factor activity across human tissues

Background

The SET binding protein 1 (SETBP1) gene encodes a transcription factor (TF) involved in various cellular processes. Distinct SETBP1 variants have been linked to three different diseases. Germline variants cause the ultra-rare pediatric Schinzel Giedion Syndrome (SGS) and SETBP1 haploinsufficiency disorder (SETBP1-HD), characterized by severe multisystemic abnormalities with neurodegeneration or a less severe brain phenotype accompanied by hypotonia and strabismus, respectively. Somatic variants in SETBP1 are associated with hematological malignancies and cancer development in other tissues in adults.

Results

To better understand the tissue-specific mechanisms involving SETBP1, we analyzed publicly available RNA-sequencing data from the Genotype-Tissue Expression (GTEx) project. We found SETBP1, and its known target genes were widely expressed across 31 adult human tissues. K-means clustering identified three distinct expression patterns of SETBP1 targets across tissues. Functional enrichment analysis (FEA) of each cluster revealed gene sets related to transcription regulation, DNA binding, and mitochondrial function. TF activity analysis of SETBP1 and its target TFs revealed tissue-specific TF activity, underscoring the role of tissue context-driven regulation and suggesting its impact in SETBP1-associated disease. In addition to uncovering tissue-specific molecular signatures of SETBP1 expression and TF activity, we provide a Shiny web application to facilitate exploring TF activity across human tissues for 758 TFs.

Conclusions

This study provides insight into the landscape of SETBP1 expression and TF activity across 31 non-diseased human tissues and reveals tissue-specific expression and activity of SETBP1 and its targets. In conjunction with the web application we constructed, our framework enables researchers to generate hypotheses related to the role tissue backgrounds play with respect to gene expression and TF activity in different disease contexts.

Zeb1 Regulates the Function of Lympho-Myeloid Primed Progenitors after Transplantation

Zeb1, a zinc finger E-box binding homeobox epithelial-mesenchymal (EMT) transcription factor, acts as a critical regulator of hematopoietic stem cell (HSC) self-renewal and multi-lineage differentiation. Whether Zeb1 directly regulates the function of multi-potent progenitors primed for hematopoietic lineage commitment remains ill defined. By using an inducible Mx-1 Cre conditional mouse model where Zeb1 was genetically engineered to be deficient in the adult hematopoietic system (hereafter Zeb1-/-), we found that the absolute cell number of immunophenotypically defined lympho-myeloid primed progenitors (LMPPs) from Zeb1-/- mice was reduced. Myeloid- and lymphoid-biased HSCs in Zeb1-/- mice were unchanged, implying that defective LMPP generation from Zeb1-/- mice was not directly caused by an imbalance of lineage-biased HSCs. Functional analysis of LMPP from Zeb1-/- mice, as judged by competitive transplantation, revealed an overall reduction in engraftment to hematopoietic organs over 4 weeks, which correlated with minimal T-cell engraftment, reduced B-cell and monocyte/macrophage engraftment, and unperturbed granulocyte engraftment. Thus, Zeb1 regulates LMPP differentiation potential to select lympho-myeloid lineages in the context of transplantation.

An "unexpected" role for EMT transcription factors in hematological development and malignancy

The epithelial to mesenchymal transition (EMT) is a fundamental developmental process essential for normal embryonic development. It is also important during various pathogenic processes including fibrosis, wound healing and epithelial cancer cell metastasis and invasion. EMT is regulated by a variety of cell signalling pathways, cell-cell interactions and microenvironmental cues, however the key drivers of EMT are transcription factors of the ZEB, TWIST and SNAIL families. Recently, novel and unexpected roles for these EMT transcription factors (EMT-TFs) during normal blood cell development have emerged, which appear to be largely independent of classical EMT processes. Furthermore, EMT-TFs have also begun to be implicated in the development and pathogenesis of malignant hematological diseases such as leukemia and lymphoma, and now present themselves or the pathways they regulate as possible new therapeutic targets within these malignancies. In this review, we discuss the ZEB, TWIST and SNAIL families of EMT-TFs, focusing on what is known about their normal roles during hematopoiesis as well as the emerging and "unexpected" contribution they play during development and progression of blood cancers.

Regulation and Functions of α6-Integrin (CD49f) in Cancer Biology

Over the past decades, our knowledge of integrins has evolved from being understood as simple cell surface adhesion molecules to receptors that have a complex range of intracellular and extracellular functions, such as delivering chemical and mechanical signals to cells. Consequently, they actively control cellular proliferation, differentiation, and apoptosis. Dysregulation of integrin signaling is a major factor in the development and progression of many tumors. Many reviews have covered the broader integrin family in molecular and cellular studies and its roles in diseases. Nevertheless, further understanding of the mechanisms specific to an individual subunit of different heterodimers is more useful. Thus, we describe the current understanding of and exploratory investigations on the α6-integrin subunit (CD49f, VLA6; encoded by the gene itga6) in normal and cancer cells. The roles of ITGA6 in cell adhesion, stemness, metastasis, angiogenesis, and drug resistance, and as a diagnosis biomarker, are discussed. The role of ITGA6 differs based on several features, such as cell background, cancer type, and post-transcriptional alterations. In addition, exosomal ITGA6 also implies metastatic organotropism. The importance of ITGA6 in the progression of a number of cancers, including hematological malignancies, suggests its potential usage as a novel prognostic or diagnostic marker and useful therapeutic target for better clinical outcomes.

E3 ubiquitin ligase on the biological properties of hematopoietic stem cell

Hematopoietic stem cells are a group of heterogeneity cells with the potential to differentiate into various types of mature blood cells. Their basic biological properties include quiescence, self-renewal, multilineage differentiation, and homing ability, with the homing of exogenous hematopoietic stem cells after transplantation becoming a new focus, while the first three properties share some similarity in mechanism due to connectivity. In various complex mechanisms, the role of E3 ubiquitin ligases in hematopoietic homeostasis and malignant transformation is receiving increasing attention. As a unique part, E3 ubiquitin ligases play an important role in physiological regulation mechanism of posttranslational modification. In this review, we focus on the recent progress of the crucial role of E3 ubiquitin ligases that target specific proteins for ubiquitination to regulate biological properties of hematopoietic stem cells. Additionally, this paper deals with E3 ubiquitin ligases that affect the biological properties through aging and summarizes the relevant applications of targeting E3 ligases in hematopoietic malignancies. We present some ideas on the clinical application of E3 ubiquitin ligase to regulate hematopoietic stem cells and also believe that it is meaningful to study the upstream signal of these E3 ubiquitin ligases because hematopoietic stem cell dysfunction is caused by deficiency of some E3 ligases.

IGF2BP2 promotes lncRNA DANCR stability mediated glycolysis and affects the progression of FLT3-ITD + acute myeloid leukemia

Internal tandem duplication (ITD) is the most common type of FLT3 mutation (FLT3-ITD), accounting for about 25% of AML patients. The expression of DANCR in FLT3-ITD AML had not been paid attention to, and whether its regulatory relationship with IGF2BP2 can affect the progression of FLT3-ITD AML was unclear. Our study sought to verify the biological role of IGF2BP2 as an m6A reading protein in FLT3-ITD AML. To further explore the role and mechanism of DANCR in AML, and provide a basis for the screening of biomarkers and the development of targeted drugs. The results show that IGF2BP2 was upregulated in FLT3-ITD+ AML patients and cells. Si-IGF2BP2 could inhibit the proliferation, glycolytic and promote the apoptosis in MV4-11 cells. IGF2BP2 could promote the DANCR RNA stability. This discovery will provide new horizons for early screening and targeted therapy of FLT3-ITD+ AML.

Deubiquitinase OTUB2 promotes intrahepatic cholangiocarcinoma progression by stabilizing the CTNNB1-ZEB1 axis

Aberrant regulation of ubiquitination is an essential fundamental process in tumors, especially intrahepatic cholangiocarcinoma (iCCA). We reported that OTUB2, an OTU deubiquitinase, is upregulated in iCCA and stabilizes the CTNNB1-ZEB1 axis, resulting in epithelial-mesenchymal transition (EMT) and iCCA metastasis. Mechanistically, OTUB2 promotes CTNNB1 expression by interacting with the E3 ligase TRAF6. OTUB2 inhibits the lysosomal degradation of CTNNB1 by interacting with TRAF6 and thus regulates the progression of iCCA through ZEB1. Clinically, high OTUB2 expression is related to increased ZEB1 expression and activity and reduced overall survival in iCCA patients. Therefore, advanced iCCA patients may benefit from drugs targeting OTUB2 and its pathway.

Ploidy-stratified single cardiomyocyte transcriptomics map Zinc Finger E-Box Binding Homeobox 1 to underly cardiomyocyte proliferation before birth

Whereas cardiomyocytes (CMs) in the fetal heart divide, postnatal CMs fail to undergo karyokinesis and/or cytokinesis and therefore become polyploid or binucleated, a key process in terminal CM differentiation. This switch from a diploid proliferative CM to a terminally differentiated polyploid CM remains an enigma and seems an obstacle for heart regeneration. Here, we set out to identify the transcriptional landscape of CMs around birth using single cell RNA sequencing (scRNA-seq) to predict transcription factors (TFs) involved in CM proliferation and terminal differentiation. To this end, we established an approach combining fluorescence activated cell sorting (FACS) with scRNA-seq of fixed CMs from developing (E16.5, P1, and P5) mouse hearts, and generated high-resolution single-cell transcriptomic maps of in vivo diploid and tetraploid CMs, increasing the CM resolution. We identified TF-networks regulating the G2/M phases of developing CMs around birth. ZEB1 (Zinc Finger E-Box Binding Homeobox 1), a hereto unknown TF in CM cell cycling, was found to regulate the highest number of cell cycle genes in cycling CMs at E16.5 but was downregulated around birth. CM ZEB1-knockdown reduced proliferation of E16.5 CMs, while ZEB1 overexpression at P0 after birth resulted in CM endoreplication. These data thus provide a ploidy stratified transcriptomic map of developing CMs and bring new insight to CM proliferation and endoreplication identifying ZEB1 as a key player in these processes.

A Zeb1/MtCK1 metabolic axis controls osteoclast activation and skeletal remodeling

Osteoclasts are bone-resorbing polykaryons responsible for skeletal remodeling during health and disease. Coincident with their differentiation from myeloid precursors, osteoclasts undergo extensive transcriptional and metabolic reprogramming in order to acquire the cellular machinery necessary to demineralize bone and digest its interwoven extracellular matrix. While attempting to identify new regulatory molecules critical to bone resorption, we discovered that murine and human osteoclast differentiation is accompanied by the expression of Zeb1, a zinc-finger transcriptional repressor whose role in normal development is most frequently linked to the control of epithelial-mesenchymal programs. However, following targeting, we find that Zeb1 serves as an unexpected regulator of osteoclast energy metabolism. In vivo, Zeb1-null osteoclasts assume a hyperactivated state, markedly decreasing bone density due to excessive resorptive activity. Mechanistically, Zeb1 acts in a rheostat-like fashion to modulate murine and human osteoclast activity by transcriptionally repressing an ATP-buffering enzyme, mitochondrial creatine kinase 1 (MtCK1), thereby controlling the phosphocreatine energy shuttle and mitochondrial respiration. Together, these studies identify a novel Zeb1/MtCK1 axis that exerts metabolic control over bone resorption in vitro and in vivo.

Exosomal ZEB1 Derived from Neural Stem Cells Reduces Inflammation Injury in OGD/R-Treated Microglia via the GPR30-TLR4-NF-κB Axis

Ischemic stroke (IS) is the most common type of stroke and the second leading cause of death overall. Neural stem cells play protective roles in IS, but the underlying mechanism remains to be determined. Neural stem cells (NSC) were obtained from the fetal brain tissue of C57BL/6J mice. NSC-derived exosomes (NSC-Exos) were identified in the conditioned medium. Internalization of NSC-Exos was analyzed by fluorescence microscopy. In vitro microglia ischemic stroke injury model was induced using oxygen glucose deprivation/re-oxygenation (OGD/R) method. Cell viability and inflammation were analyzed by MTT, qPCR, ELISA and Western blotting assay. Interaction between ZEB1 and the promoter of GPR30 was verified by luciferase assay and chromatin immunoprecipitation. NSC-Exos prevented OGD/R-mediated inhibition of cell survival and the production of inflammatory cytokines in microglia cells. NSC-Exos increased ZEB1 expression in OGD/R-treated microglia. Down-regulation of ZEB1 expression in NSC-Exos abolished NSC-Exos' protective effects on OGD/R-treated microglia. ZEB1 bound to the promoter region of GPR30 and promoted its expression. Inhibiting GPR30 reversed NSC-Exos effects on cell viability and inflammation injury in OGD/R-treated microglia. Our study demonstrated that NSC exerted cytoprotective roles through release of exosomal ZEB1,which transcriptionally upregulated GPR30 expression, resulting in a reduction in TLR4/NF-κB pathway-induced inflammation. These findings shed light on NSC-Exos' cytoprotective mechanism and highlighted its potential application in the treatment of IS.

Transcriptional factors targeting in cancer stem cells for tumor modulation

Cancer Stem Cells (CSCs) are now considered the primary "seeds" for the onset, development, metastasis, and recurrence of tumors. Despite therapeutic breakthroughs, cancer remains the leading cause of death worldwide. This is because the tumor microenvironment contains a key population of cells known as CSCs, which promote tumor aggression. CSCs are self-renewing cells that aid tumor recurrence by promoting tumor growth and persisting in patients after many traditional cancer treatments. According to reports, numerous transcription factors (TF) play a key role in maintaining CSC pluripotency and its self-renewal property. The understanding of the functions, structures, and interactional dynamics of these transcription factors with DNA has modified the hypothesis, paving the way for novel transcription factor-targeted therapies. These TFs, which are crucial and are required by cancer cells, play a vital function in the etiology of human cancer. Such CSC TFs will help with gene expression profiling, which provides crucial data for predicting the prognosis of patients. To overcome anti-cancer medication resistance and completely eradicate cancer, a potent therapy combining TFs-based CSC targets with traditional chemotherapy may be developed. In order to develop therapies that could eliminate CSCs, we here concentrated on the effect of TFs and other components of signalling pathways on cancer stemness.

Single-cell resolution reveals RalA GTPase expanding hematopoietic stem cells and facilitating of BCR-ABL1-driven leukemogenesis in a CRISPR/Cas9 gene editing mouse model

BCR-ABL oncogene-mediated Philadelphia chromosome-positive (Ph+) chronic myeloid leukemia (CML) is suggested to originate from leukemic stem cells (LSCs); however, factors regulating self-renewal of LSC and normal hematopoietic stem cells (HSCs) are largely unclear. Here, we show that RalA, a small GTPase in the Ras downstream signaling pathway, has a critical effect on regulating the self-renewal of LSCs and HSCs. A RalA knock-in mouse model (RalA^Rosa26-Tg/+) was initially constructed on the basis of the Clustered Regularly Interspaced Short Palindromic Repeats/Cas9 (CRISPR/Cas9) assay to analyze normal hematopoietic differentiation frequency using single-cell resolution and flow cytometry. RalA overexpression promoted cell cycle progression and increased the frequency of granulocyte-monocyte progenitors (GMPs), HSCs and multipotent progenitors (MPPs). The uniform manifold approximation and projection (UMAP) plot revealed heterogeneities in HSCs and progenitor cells (HSPCs) and identified the subclusters of HSCs and GMPs with a distinct molecular signature. RalA also promoted BCR-ABL-induced leukemogenesis and self-renewal of primary LSCs and shortened the survival of leukemic mice. RalA knockdown prolonged survival and promoted sensitivity to imatinib in a patient-derived tumor xenograft model. Immunoprecipitation plus single-cell RNA sequencing of the GMP population confirmed that RalA induced this effect by interacting with RAC1. RAC1 inhibition by azathioprine effectively reduced the self-renewal, colony formation ability of LSCs and prolonged the survival in BCR-ABL1-driven RalA overexpression CML mice. Collectively, RalA was detected to be a vital factor that regulates the abilities of HSCs and LSCs, thus facilitating BCR-ABL-triggered leukemia in mice. RalA inhibition serves as the therapeutic approach to eradicate LSCs in CML.

The role of the ZEB1–neuroinflammation axis in CNS disorders

Zinc finger E-box binding homeobox 1 (ZEB1) is a master modulator of the epithelial–mesenchymal transition (EMT), a process whereby epithelial cells undergo a series of molecular changes and express certain characteristics of mesenchymal cells. ZEB1, in association with other EMT transcription factors, promotes neuroinflammation through changes in the production of inflammatory mediators, the morphology and function of immune cells, and multiple signaling pathways that mediate the inflammatory response. The ZEB1–neuroinflammation axis plays a pivotal role in the pathogenesis of different CNS disorders, such as brain tumors, multiple sclerosis, cerebrovascular diseases, and neuropathic pain, by promoting tumor cell proliferation and invasiveness, formation of the hostile inflammatory micromilieu surrounding neuronal tissues, dysfunction of microglia and astrocytes, impairment of angiogenesis, and dysfunction of the blood–brain barrier. Future studies are needed to elucidate whether the ZEB1–neuroinflammation axis could serve as a diagnostic, prognostic, and/or therapeutic target for CNS disorders.

Low expression of the metabolism-related gene SLC25A21 predicts unfavourable prognosis in patients with acute myeloid leukaemia

Acute myeloid leukaemia (AML) is a heterogeneous disease associated with poor outcomes. To identify AML-specific genes with prognostic value, we analysed transcriptome and clinical information from The Cancer Genome Atlas (TCGA) database, Gene Expression Omnibus (GEO) datasets, and Genotype-Tissue Expression (GTEx) project. The metabolism-related gene, SLC25A21 was found to be significantly downregulated in AML, and was associated with high white blood cell (WBC) counts, high pretrial blood (PB) and bone marrow (BM) blast abundance, FLT3 mutation, NPM1 mutation, and death events (all p value <0.05). We validated the expression of SLC25A21 in our clinical cohort, and found that SLC25A21 was downregulated in AML. Moreover, we identified low expression of SLC25A21 as an independent prognostic factor by univariate Cox regression (hazard ratio [HR]: 0.550; 95% Confidence interval [CI]: 0.358–0.845; p value = 0.006) and multivariate Cox regression analysis (HR: 0.341; 95% CI: 0.209–0.557; p value <0.05). A survival prediction nomogram was established with a C-index of 0.735, which indicated reliable prognostic prediction. Subsequently, based on the median SLC25A21 expression level, patients in the TCGA-LAML cohort were divided into low- and high-expression groups. Gene ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses of DEGs highlighted growth factor binding, extracellular structure organization, cytokine‒cytokine receptor interaction, etc. The results of gene set enrichment analysis (GSEA) indicated that the epithelial-mesenchymal transition, KRAS signalling, oxidative phosphorylation, and reactive oxygen species pathways were enriched. Through gene coexpression and protein‒protein interaction (PPI) network analysis, we identified two hub genes, EGFR and COL1A2, which were linked to worse clinical outcomes. Furthermore, we found that lower SLC25A21 expression was closely associated with a significant reduction in the levels of infiltrating immune cells, which might be associated with immune escape of AML cells. A similar trend was observed for the expression of checkpoint genes (CTLA4, LAG3, TIGIT, and HAVCR2). Finally, drug sensitivity testing suggested that the low-expression SLC25A21 group is sensitive to doxorubicin, mitomycin C, linifanib but resistant to JQ1, belinostat, and dasatinib. Hence, our study demonstrated that a low expression level of SLC25A21 predicts an unfavourable prognosis in patients with AML.

Zeb1 sustains hematopoietic stem cell functions by suppressing mitofusin-2-mediated mitochondrial fusion

Metabolic status is essential in maintaining normal functions of hematopoietic stem cells (HSCs). However, how the dynamic of the mitochondrion, as a central organelle in metabolism, is molecularly regulated to orchestrate metabolism and HSC stemness remains to be elucidated. Here, we focus on the role of Zeb1, a well-characterized epithelial-to-mesenchymal transition (EMT) inducer which has been demonstrated to confer stem-cell-like characteristics in multiple cancer types in stemness regulation of HSCs. Using a Zeb1-tdTomato reporter mouse model, we find that Zeb1⁺Lin^-Sca-1⁺c-Kit⁺ cells (Zeb1⁺-LSKs) represent a subset of functional long-term HSCs. Zeb1⁺LSKs exhibit a reduced reactive oxygen species (ROS) level, low mitochondrial mass, low mitochondrial membrane potential (MMP), and particularly small, round fragmented mitochondria. Of note, ectopic expression of Zeb1 leads to a fragmented mitochondrial morphology with a low mitochondrial metabolic status in EML cells. In addition, Zeb1-knockout (Zeb1-KO) LSKs from fetal liver display an exhausted stem-cell activity. Zeb1 deficiency results in elongated and tubulated mitochondria with increased mitochondrial mass, elevated MMP, and higher ROS production. Mechanistically, Zeb1 acts as a transcriptional suppressor on the key mitochondrial-fusion protein Mitofusin-2 (encoded by Mfn2). We highlight an important role of Zeb1 in the regulation of mitochondrial morphology in HSC and the metabolic control of HSC stemness by repressing Mfn2-mediated mitochondrial fusion.

The Role of NOTCH1, GATA3, and c-MYC in T Cell Non-Hodgkin Lymphomas

Lymphomas are heterogeneous malignant tumours of white blood cells characterised by the aberrant proliferation of mature lymphoid cells or their precursors. Lymphomas are classified into main types depending on the histopathologic evidence of biopsy taken from an enlarged lymph node, progress stages, treatment strategies, and outcomes: Hodgkin and non-Hodgkin lymphoma (NHL). Moreover, lymphomas can be further divided into subtypes depending on the cell origin, and immunophenotypic and genetic aberrations. Many factors play vital roles in the progression, pathogenicity, incidence, and mortality rate of lymphomas. Among NHLs, peripheral T cell lymphomas (PTCLs) are rare lymphoid malignancies, that have various cellular morphology and genetic mutations. The clinical presentations are usually observed at the advanced stage of the disease. Many recent studies have reported that the expressions of NOTCH1, GATA3, and c-MYC are associated with poorer prognosis in PTCL and are involved in downstream activities. However, questions have been raised about the pathological relationship between these factors in PTCLs. Therefore, in this review, we investigate the role and relationship of the NOTCH1 pathway, transcriptional factor GATA3 and proto-oncogene c-MYC in normal T cell development and malignant PTCL subtypes.

Epithelial–mesenchymal transition: The history, regulatory mechanism, and cancer therapeutic opportunities

Epithelial–mesenchymal transition (EMT) is a program wherein epithelial cells lose their junctions and polarity while acquiring mesenchymal properties and invasive ability. Originally defined as an embryogenesis event, EMT has been recognized as a crucial process in tumor progression. During EMT, cell–cell junctions and cell–matrix attachments are disrupted, and the cytoskeleton is remodeled to enhance mobility of cells. This transition of phenotype is largely driven by a group of key transcription factors, typically Snail, Twist, and ZEB, through epigenetic repression of epithelial markers, transcriptional activation of matrix metalloproteinases, and reorganization of cytoskeleton. Mechanistically, EMT is orchestrated by multiple pathways, especially those involved in embryogenesis such as TGFβ, Wnt, Hedgehog, and Hippo, suggesting EMT as an intrinsic link between embryonic development and cancer progression. In addition, redox signaling has also emerged as critical EMT modulator. EMT confers cancer cells with increased metastatic potential and drug resistant capacity, which accounts for tumor recurrence in most clinic cases. Thus, targeting EMT can be a therapeutic option providing a chance of cure for cancer patients. Here, we introduce a brief history of EMT and summarize recent advances in understanding EMT mechanisms, as well as highlighting the therapeutic opportunities by targeting EMT in cancer treatment.

Expression of Zeb1 in the differentiation of mouse embryonic stem cell

Embryonic stem cells (ESCs) differentiation is a process of replication and refinement, and the directional lineage differentiation of ESCs involves the epithelial-mesenchymal transition (EMT)- mesenchymal-epithelial transition (MET) process. A previous study revealed that Zinc finger E-box-binding homeobox 1 (Zeb1) plays a vital role in EMT, which could repress E-cadherin promoter and induce an EMT in cells. To verify the expression of Zeb1 and its correlation with Lin28a in mouse ESCs differentiation, we performed qRT-PCR and western blots to detect the expression of Lin28a mRNA and protein after Zeb1 knockdown. The expression of Zeb1 decreased over time of mouse ESCs differentiation but significantly increased in mouse embryonal carcinoma cells. After knockdown of Zeb1, Lin28a and Vimentin expression were decreased, while E-cadherin expression increased both in mouse ESCs, EBs, GC1, and P19 cells. We found that Zeb1 promoted the invasive ability of mouse embryonal carcinoma cells. These results revealed that expression of Zeb1 decreased during the differentiation of ESCs, and Lin28a and EMT processes can be regulated by Zeb1, which need to be verified in the future studies.

Noncoding RNAs and Their Response Predictive Value in Azacitidine-treated Patients With Myelodysplastic Syndrome and Acute Myeloid Leukemia With Myelodysplasia-related Changes

BACKGROUND/AIM

Prediction of response to azacitidine (AZA) treatment is an important challenge in hematooncology. In addition to protein coding genes (PCGs), AZA efficiency is influenced by various noncoding RNAs (ncRNAs), including long ncRNAs (lncRNAs), circular RNAs (circRNAs), and transposable elements (TEs).

MATERIALS AND METHODS

RNA sequencing was performed in patients with myelodysplastic syndromes or acute myeloid leukemia before AZA treatment to assess contribution of ncRNAs to AZA mechanisms and propose novel disease prediction biomarkers.

RESULTS

Our analyses showed that lncRNAs had the strongest predictive potential. The combined set of the best predictors included 14 lncRNAs, and only four PCGs, one circRNA, and no TEs. Epigenetic regulation and recombinational repair were suggested as crucial for AZA response, and network modeling defined three deregulated lncRNAs (CTC-482H14.5, RP11-419K12.2, and RP11-736I24.4) associated with these processes.

CONCLUSION

The expression of various ncRNAs can influence the effect of AZA and new ncRNA-based predictive biomarkers can be defined.

Epigenetic modifications inhibit the expression of MARVELD1 and in turn tumorigenesis by regulating the Wnt/β-catenin pathway in pan-cancer

MARVEL domain-containing 1 (MARVELD1) is one of the MARVEL domain-containing proteins. Expression of MARVELD1 in tumor and non-tumor tissues, the relationship between its expression and cancer prognosis, and upstream regulation of MARVELD1 were examined using pan-cancer data from The Cancer Genome Atlas. MARVELD1 expression was significantly downregulated in tissues used for pan-cancer analysis compared to that in normal tissues. Low expression of MARVELD1 was associated with poor disease outcomes in pan-cancer. Colon cancer patients with low expression of MARVELD1 had worse progression free survival and overall survival than those with high expression levels in our cohort. Hypermethylation and histone modification in the MARVELD1 promoter locus synergistically affected its expression in pan-cancer. The function of MARVELD1 in colon cancer remains to be studied. Gene Ontology enrichment analysis revealed that MARVELD1 may modulate processes associated with inhibition of tumorigenesis in colon cancer. Both upstream transcription factors and downstream functional enrichment of MARVELD1 were related to the Wnt/β-catenin signaling pathway. Overexpression of MARVELD1 inhibited the expression of β-catenin and its entry into the nucleus. MARVELD1 also inhibited the proliferation, migration, and invasion of colon cancer cells. With Wnt/β-catenin activator LiCl treatment, rescue experiments demonstrated that the role of MARVELD1 in colon cancer progression was dependent on the Wnt/β-catenin pathway. These results indicate that MARVELD1 acts as a tumor suppressor and inhibits tumorigenesis via the Wnt/β-catenin pathway.

ZNF521 Enhances MLL-AF9-Dependent Hematopoietic Stem Cell Transformation in Acute Myeloid Leukemias by Altering the Gene Expression Landscape

Leukemias derived from the MLL-AF9 rearrangement rely on dysfunctional transcriptional networks. ZNF521, a transcription co-factor implicated in the control of hematopoiesis, has been proposed to sustain leukemic transformation in collaboration with other oncogenes. Here, we demonstrate that ZNF521 mRNA levels correlate with specific genetic aberrations: in particular, the highest expression is observed in AMLs bearing MLL rearrangements, while the lowest is detected in AMLs with FLT3-ITD, NPM1, or CEBPα double mutations. In cord blood-derived CD34⁺ cells, enforced expression of ZNF521 provides a significant proliferative advantage and enhances MLL-AF9 effects on the induction of proliferation and the expansion of leukemic progenitor cells. Transcriptome analysis of primary CD34⁺ cultures displayed subsets of genes up-regulated by MLL-AF9 or ZNF521 single transgene overexpression as well as in MLL-AF9/ZNF521 combinations, at either the early or late time points of an in vitro leukemogenesis model. The silencing of ZNF521 in the MLL-AF9 + THP-1 cell line coherently results in an impairment of growth and clonogenicity, recapitulating the effects observed in primary cells. Taken together, these results underscore a role for ZNF521 in sustaining the self-renewal of the immature AML compartment, most likely through the perturbation of the gene expression landscape, which ultimately favors the expansion of MLL-AF9-transformed leukemic clones.

Interplay between the EMT transcription factors ZEB1 and ZEB2 regulates hematopoietic stem and progenitor cell differentiation and hematopoietic lineage fidelity

The ZEB2 transcription factor has been demonstrated to play important roles in hematopoiesis and leukemic transformation. ZEB1 is a close family member of ZEB2 but has remained more enigmatic concerning its roles in hematopoiesis. Here, we show using conditional loss-of-function approaches and bone marrow (BM) reconstitution experiments that ZEB1 plays a cell-autonomous role in hematopoietic lineage differentiation, particularly as a positive regulator of monocyte development in addition to its previously reported important role in T-cell differentiation. Analysis of existing single-cell (sc) RNA sequencing (RNA-seq) data of early hematopoiesis has revealed distinctive expression differences between Zeb1 and Zeb2 in hematopoietic stem and progenitor cell (HSPC) differentiation, with Zeb2 being more highly and broadly expressed than Zeb1 except at a key transition point (short-term HSC [ST-HSC]➔MPP1), whereby Zeb1 appears to be the dominantly expressed family member. Inducible genetic inactivation of both Zeb1 and Zeb2 using a tamoxifen-inducible Cre-mediated approach leads to acute BM failure at this transition point with increased long-term and short-term hematopoietic stem cell numbers and an accompanying decrease in all hematopoietic lineage differentiation. Bioinformatics analysis of RNA-seq data has revealed that ZEB2 acts predominantly as a transcriptional repressor involved in restraining mature hematopoietic lineage gene expression programs from being expressed too early in HSPCs. ZEB1 appears to fine-tune this repressive role during hematopoiesis to ensure hematopoietic lineage fidelity. Analysis of Rosa26 locus–based transgenic models has revealed that Zeb1 as well as Zeb2 cDNA-based overexpression within the hematopoietic system can drive extramedullary hematopoiesis/splenomegaly and enhance monocyte development. Finally, inactivation of Zeb2 alone or Zeb1/2 together was found to enhance survival in secondary MLL-AF9 acute myeloid leukemia (AML) models attesting to the oncogenic role of ZEB1/2 in AML.

This study shows that the closely related transcription factors ZEB1 and ZEB2 cooperate to restrain myeloid and lymphoid differentiation programs in hematopoietic stem and progenitor cells, ensuring fidelity of differentiation in multiple lineages.

Combined delivery of salinomycin and docetaxel by dual-targeting gelatinase nanoparticles effectively inhibits cervical cancer cells and cancer stem cells

Intra-tumor heterogeneity is widely accepted as one of the key factors, which hinders cancer patients from achieving full recovery. Especially, cancer stem cells (CSCs) may exhibit self-renewal capacity, which makes it harder for complete elimination of tumor. Therefore, simultaneously inhibiting CSCs and non-CSCs in tumors becomes a promising strategy to obtain sustainable anticancer efficacy. Salinomycin (Sal) was reported to be critical to inhibit CSCs. However, the poor bioavailability and catastrophic side effects brought about limitations to clinical practice. To solve this problem, we previously constructed gelatinase-stimuli nanoparticles composed of nontoxic, biocompatible polyethylene glycol-polycaprolactone (PEG-PCL) copolymer with a gelatinase-cleavable peptide Pro-Val-Gly-Leu-Iso-Gly (PVGLIG) inserted between the two blocks of the copolymer. By applying our “smart” gelatinase-responsive nanoparticles for Sal delivery, we have demonstrated specific accumulation in tumor, anti-CSCs ability and reduced toxicity of Sal-NPs in our previous study. In the present study, we synthesized Sal-Docetaxel-loaded gelatinase-stimuli nanoparticles (Sal-Doc NP) and confirmed single emulsion as the optimal method of producing Sal-Doc NPs (Sal-Doc SE-NP) in comparison with nanoprecipitation. Sal-Doc SE-NPs inhibited both CSCs and non-CSCs in mice transplanted with cervical cancer, and might be associated with enhanced restriction of epithelial-mesenchymal transition (EMT) pathway. Besides, the tumorigenic capacity and growing speed were obviously suppressed in Sal-Doc-SE-NPs-treated group in rechallenge experiment. Our results suggest that Sal-Doc-loaded gelatinase-stimuli nanoparticles could be a promising strategy to enhance antitumor efficacy and reduce side effects by simultaneously suppressing CSCs and non-CSCs.