RUNX1 inhibits proliferation and induces apoptosis of t(8;21) leukemia cells via KLF4-mediated transactivation of P57

A loss-of-function variant in KLF4 affecting zinc finger motifs causes progressive symmetric erythrokeratodermia

We identified a novel de novo variant (c.1234C > A, p.His412Asn) in KLF4, which is located within the first zinc finger motifs of KLF4, in a patient with progressive symmetric erythrokeratodermia. By dual-luciferase reporter assay, quantitative reverse transcriptase-polymerase chain reaction and immunofluorescence, we demonstrated that the KLF4 variant is a loss-of-function mutation, and the expression of SLURP1 and DSG1, both of which are transcriptionally regulated by KLF4, was downregulated.

LncRNA H19 Inhibits Keratinocyte Cell Proliferation and Migration by Targeting miR-17-5p/RUNX1 Axis in Chronic Wounds

The migration and proliferation of keratinocytes are critical for re-epithelization during chronic wound healing. Runt-related transcription factor 1 (RUNX1) has been indicated to repress keratinocyte proliferation. Nonetheless, the potential molecular mechanism of RUNX1 in regulating keratinocyte proliferation and migration remains unclear. Cell counting kit-8 and wound-healing assays were implemented for examining keratinocyte viability and migration, respectively. Western blotting and real-time quantitative polymerase chain reaction were utilized for quantifying protein and RNA levels. Luciferase reporter assay was employed for verifying the interaction between RUNX1, miR-17-5p, and long noncoding RNA H19. The results showed that RUNX1 depletion promoted keratinocyte proliferation and migration and repressed extracellular matrix degradation. Mechanistically, H19 upregulated RUNX1 expression by competitively absorbing miR-17-5p. Rescue experiments revealed that overexpressing RUNX1 reversed H19 silencing-mediated effects on the phenotypes of keratinocytes. In conclusion, H19 knockdown promotes keratinocyte proliferation and migration and suppresses extracellular matrix degradation via the miR-17-5p/RUNX1 axis.

RUNX1 knockdown induced apoptosis and impaired EMT in high-grade serous ovarian cancer cells

Ovarian cancer is the leading cause of death from gynecologic illnesses worldwide. High-grade serous ovarian cancer (HGSOC) is a gynecological tumor that accounts for roughly 70% of ovarian cancer deaths in women. Runt-related transcription factor 1(RUNX1) proteins were identified with overexpression in the HGSOC. However, the roles of RUNX1 in the development of HGSOC are poorly understood. In this study, combined with whole-transcriptome analysis and multiple research methods, RUNX1 was identified as vital in developing HGSOC. RUNX1 knockdown inhibits the physiological function of ovarian cancer cells and regulates apoptosis through the FOXO1-Bcl2 axis. Down-regulated RUNX1 impairs EMT function through the EGFR-AKT-STAT3 axis signaling. In addition, RUNX1 knockdown can significantly increase the sensitivity to clinical drug therapy for ovarian cancer. It is strongly suggested that RUNX1 work as a potential diagnostic and therapeutic target for HGSOC patients with better prognoses and treatment options. It is possible to generate novel potential targeted therapy strategies and translational applications for serous ovarian carcinoma patients with better clinical outcomes.

CST2 is activated by RUNX1 and promotes pancreatic cancer progression by activating PI3K/AKT pathway

Cystatin 2 (CST2) is a protein coding gene that belongs to a large superfamily of cysteine protease inhibitors. The deregulation of CST2 has been implicated in human cancers. The role of CST2 in pancreatic carcinogenesis has not yet been investigated. In this study, Gene Expression Profiling Interactive Analysis was performed using the Cancer Genome Atlas (TCGA) dataset containing pancreatic tumor samples and normal tissues. The functional role of CST2 in pancreatic cells was investigated by gene knockdown in vitro and in mouse xenograft tumor model. We found that CST2 was overexpressed in pancreatic tumor samples and cell lines. The knockdown of CST2 led to reduced proliferation, migration, and invasion, while apoptotic events were increased upon CST2 silencing in pancreatic cancer cells. In the xenograft mouse model of pancreatic cells, CST2 knockdown also retarded tumor growth on tumor growth. RUNX1 was identified as a transcription factor which positively regulated the expression of CST2. Further, we showed that, CST2 knockdown suppressed the activation of the PI3K/AKT signaling in pancreatic cells. Overall, our findings suggest that CST2 serves as an oncogene which facilitates the progression of pancreatic cancer. RUNX1 functions to upregulate CST2 in pancreatic cancer cells and CST2 may promote the malignancy of pancreatic cells by maintaining the activation of PI3K/AKT signaling.

Tasmanian devil cathelicidins exhibit anticancer activity against Devil Facial Tumour Disease (DFTD) cells

The Tasmanian devil (Sarcophilus harrisii) is endangered due to the spread of Devil Facial Tumour Disease (DFTD), a contagious cancer with no current treatment options. Here we test whether seven recently characterized Tasmanian devil cathelicidins are involved in cancer regulation. We measured DFTD cell viability in vitro following incubation with each of the seven peptides and describe the effect of each on gene expression in treated cells. Four cathelicidins (Saha-CATH3, 4, 5 and 6) were toxic to DFTD cells and caused general signs of cellular stress. The most toxic peptide (Saha-CATH5) also suppressed the ERBB and YAP1/TAZ signaling pathways, both of which have been identified as important drivers of cancer proliferation. Three cathelicidins induced inflammatory pathways in DFTD cells that may potentially recruit immune cells in vivo. This study suggests that devil cathelicidins have some anti-cancer and inflammatory functions and should be explored further to determine whether they have potential as treatment leads.

Long non-coding RNA DLX6-AS1 is the key mediator of glomerular podocyte injury and albuminuria in diabetic nephropathy by targeting the miR-346/GSK-3β signaling pathway

Progressive albuminuria is the primary clinical symptom of diabetic nephropathy (DN), leading to a gradual decline in kidney function. DLX6-AS1 was the first reported long non-coding RNA (lncRNA) to participate in organogenesis and play crucial roles in the brain or neural cell development. Herein, we investigated the DLX6-AS1 (Dlx6-os1 in mice) role in DN pathogenesis. We found that DLX6-AS1 expression in DN patients correlated with the extent of albuminuria. Dlx6-os1 overexpression induced cellular damage and inflammatory responses in cultured podocytes through miR-346-mediated regulation of the GSK-3β pathway. In various established diabetic and newly developed knockout mouse models, Dlx6-os1 knockdown/knockout significantly reduced podocyte injury and albuminuria. The Dlx6-os1 effects were remarkably modulated by miR-346 mimics or mutants and significantly diminished in podocyte-specific GSK-3β-knockout mice. Thus, DLX6-AS1 (Dlx6-os1) promotes DN development by accelerating podocyte injury and inflammation through the upregulation of the GSK-3β pathway, providing a novel molecular target for DN therapy.

RUNX1 Is Regulated by Androgen Receptor to Promote Cancer Stem Markers and Chemotherapy Resistance in Triple Negative Breast Cancer

Triple negative breast cancer (TNBC) is an aggressive breast cancer subtype for which no effective targeted therapies are available. Growing evidence suggests that chemotherapy-resistant cancer cells with stem-like properties (CSC) may repopulate the tumor. The androgen receptor (AR) is expressed in up to 50% of TNBCs, and AR inhibition decreases CSC and tumor initiation. Runt-related transcription factor 1 (RUNX1) correlates with poor prognosis in TNBC and is regulated by the AR in prostate cancer. Our group has shown that RUNX1 promotes TNBC cell migration and regulates tumor gene expression. We hypothesized that RUNX1 is regulated by the AR and that both may work together in TNBC CSC to promote disease recurrence following chemotherapy. Chromatin immunoprecipitation sequencing (ChIP-seq) experiments in MDA-MB-453 revealed AR binding to RUNX1 regulatory regions. RUNX1 expression is upregulated by dihydrotestosterone (DHT) in MDA-MB-453 and in an AR⁺-TNBC HCI-009 patient-derived xenograft (PDX) tumors (p < 0.05). RUNX1 is increased in a CSC-like experimental model in MDA-MB-453 and SUM-159PT cells (p < 0.05). Inhibition of RUNX1 transcriptional activity reduced the expression of CSC markers. Interestingly, RUNX1 inhibition reduced cell viability and enhanced paclitaxel and enzalutamide sensitivity. Targeting RUNX1 may be an attractive strategy to potentiate the anti-tumor effects of AR inhibition, specifically in the slow-growing CSC-like populations that resist chemotherapy which lead to metastatic disease.

Identification of the Potential Molecular Mechanisms Linking RUNX1 Activity with Nonalcoholic Fatty Liver Disease, by Means of Systems Biology

Nonalcoholic fatty liver disease (NAFLD) is the most prevalent chronic hepatic disease; nevertheless, no definitive diagnostic method exists yet, apart from invasive liver biopsy, and nor is there a specific approved treatment. Runt-related transcription factor 1 (RUNX1) plays a major role in angiogenesis and inflammation; however, its link with NAFLD is unclear as controversial results have been reported. Thus, the objective of this work was to determine the proteins involved in the molecular mechanisms between RUNX1 and NAFLD, by means of systems biology. First, a mathematical model that simulates NAFLD pathophysiology was generated by analyzing Anaxomics databases and reviewing available scientific literature. Artificial neural networks established NAFLD pathophysiological processes functionally related to RUNX1: hepatic insulin resistance, lipotoxicity, and hepatic injury-liver fibrosis. Our study indicated that RUNX1 might have a high relationship with hepatic injury-liver fibrosis, and a medium relationship with lipotoxicity and insulin resistance motives. Additionally, we found five RUNX1-regulated proteins with a direct involvement in NAFLD motives, which were NFκB1, NFκB2, TNF, ADIPOQ, and IL-6. In conclusion, we suggested a relationship between RUNX1 and NAFLD since RUNX1 seems to regulate NAFLD molecular pathways, posing it as a potential therapeutic target of NAFLD, although more studies in this field are needed.

GCN5 participates in KLF4-VEGFA feedback to promote endometrial angiogenesis

Endometrial angiogenesis is necessary for good endometrial receptivity. Krüppel-like factor 4 (KLF4) is a transcription factor that is essential for regulating angiogenesis. Here we found that vascular endothelial growth factor A (VEGFA) can form a positive feedback loop with KLF4 to promote the proliferation and migration of human endometrial microvascular endothelial cells (HEMECs) and inhibit cell apoptosis. General control non-derepressible 5 (GCN5) is also time-dependent on VEGFA and participates in the KLF4-VEGFA loop. In addition, we found that GCN5 is a succinyltransferase that modulates the succinylation of histones and nonhistones. GCN5 interacts with KLF4 and is recruited to the KLF4-binding site of the VEGFA promoter to succinylate H3K79, which initiates gene transcription epigenetically. For nonhistones, GCN5 succinylates KLF4 that is activated by ERK signaling in HEMECs treated with VEGFA to increase its transcription activity. These results demonstrate KLF4-VEGFA positive feedback loop is regulated by epigenetics, which contributes to endometrial angiogenesis.

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KLF4 mediates VEGFA-induced endometrial angiogenesis

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VEGFA increases the interaction between KLF4 and GCN5

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VEGFA promotes H3K79 succinylation by upregulating KLF4 and GCN5

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VEGFA succinylates KLF4 and promotes interaction of KLF4 and GCN5 via ERK pathway

NOXA expression drives synthetic lethality to RUNX1 inhibition in pancreatic cancer

Recent evidence demonstrated the existence of molecular subtypes in pancreatic ductal adenocarcinoma (PDAC), which resist all current therapies. The paucity of therapeutic options, including a complete lack of targeted therapies, underscores the urgent and unmet medical need for the identification of targets and novel treatment strategies for PDAC. Our study unravels a function of the transcription factor RUNX1 in apoptosis regulation in PDAC. We show that pharmacological RUNX1 inhibition in PDAC is feasible and leads to NOXA-dependent apoptosis. The development of targeted therapies that influence the transcriptional landscape of PDAC might have great benefits for patients who are resistant to conventional therapies. RUNX1 inhibition as a new therapeutic intervention offers an attractive strategy for future therapies.

Evasion from drug-induced apoptosis is a crucial mechanism of cancer treatment resistance. The proapoptotic protein NOXA marks an aggressive pancreatic ductal adenocarcinoma (PDAC) subtype. To identify drugs that unleash the death-inducing potential of NOXA, we performed an unbiased drug screening experiment. In NOXA-deficient isogenic cellular models, we identified an inhibitor of the transcription factor heterodimer CBFβ/RUNX1. By genetic gain and loss of function experiments, we validated that the mode of action depends on RUNX1 and NOXA. Of note is that RUNX1 expression is significantly higher in PDACs compared to normal pancreas. We show that pharmacological RUNX1 inhibition significantly blocks tumor growth in vivo and in primary patient-derived PDAC organoids. Through genome-wide analysis, we detected that RUNX1-loss reshapes the epigenetic landscape, which gains H3K27ac enrichment at the NOXA promoter. Our study demonstrates a previously unknown mechanism of NOXA-dependent cell death, which can be triggered pharmaceutically. Therefore, our data show a way to target a therapy-resistant PDAC, an unmet clinical need.

Epigenetic silencing of UBXN8 contributes to leukemogenesis in t(8;21) acute myeloid leukemia

The formation of the RUNX1-RUNX1T1 fusion protein, resulting from the t(8;21) translocation, is considered to be one of the initiating events of t(8;21) acute myeloid leukemia (AML). However, the mechanisms of the oncogenic mechanism of RUNX1-RUNX1T1 remain unclear. In this study, we found that RUNX1-RUNX1T1 triggers the heterochromatic silencing of UBXN8 by recognizing the RUNX1-binding sites and recruiting chromatin-remodeling enzymes to the UBXN8 promoter region. Decitabine, a specific inhibitor of DNA methylation, upregulated the expression of UBXN8 in RUNX1-RUNX1T1⁺ AML cell lines. Overexpression of UBXN8 inhibited the proliferation and colony-forming ability of and promoted cell cycle arrest in t(8;21) AML cell lines. Enhancing UBXN8 levels can significantly inhibit tumor proliferation and promote the differentiation of RUNX1-RUNX1T1⁺ cells in vivo. In conclusion, our results indicated that epigenetic silencing of UBXN8 via methylation of its promoter region mediated by the RUNX1-RUNX1T1 fusion protein contributes to the leukemogenesis of t(8;21) AML and that UBXN8 targeting may be a potential therapeutic strategy for t(8;21) AML.

The protein byproduct of a common chromosomal rearrangement in acute myeloid leukemia (AML) promotes cancerous growth by inhibiting a tumor suppressor protein. AML cells that exhibit an abnormal coupling of segments from chromosomes 8 and 21 produce a fusion protein known as RUNX1-RUNX1T1. Erna Yang of Shenzhen University General Hospital, China, and colleagues have identified a mechanism by which this protein promotes AML progression. Experiments with AML cell lines showed that RUNX1-RUNX1T1 recruits DNA-binding proteins that introduce numerous chemical modifications to the UBXN8 gene, which inhibit production of the tumor suppressor protein it codes for. Drugs that block these modifications and stimulate UBXN8 activity also arrest tumor cell division. Experiments in mice confirmed that enhanced UBXN8 expression offers a defense against AML progression, suggesting a promising therapeutic approach.

Runx Transcription Factors in T Cells-What Is Beyond Thymic Development?

Runx proteins (also known as Runt-domain transcription factors) have been studied for a long time as key regulators of cellular differentiation. RUNX2 has been described as essential for osteogenesis, whereas RUNX1 and RUNX3 are known to control blood cell development during different stages of cell lineage specification. However, recent studies show evidence of complex relationships between RUNX proteins, chromatin-modifying machinery, the cytoskeleton and different transcription factors in various non-embryonic contexts, including mature T cell homeostasis, inflammation and cancer. In this review, we discuss the diversity of Runx functions in mature T helper cells, such as production of cytokines and chemokines by different CD4 T cell populations; apoptosis; and immunologic memory acquisition. We then briefly cover recent findings about the contribution of RUNX1, RUNX2 and RUNX3 to various immunologic diseases. Finally, we discuss areas that require further study to better understand the role that Runx proteins play in inflammation and immunity.

miR-7 regulates the apoptosis of chicken primary myoblasts through the KLF4 gene

1. MicroRNAs (miRNAs) play a vital role in the proliferation, differentiation, and apoptosis of myoblasts. However, the effect of miR-7 on the apoptosis of chicken primary myoblasts (CPMs) and its mechanism is still unclear.2. In this study, the expression of apoptosis marker genes (RAF1, Caspase3, Caspase9, Cytc, Fas) in CPMs was significantly increased after transfection of miR-7 mimic. The expression of the apoptosis marker genes in CPMs was significantly reduced after transfection with miR-7 inhibitor. Flow cytometry showed that the late apoptosis rate of the mimic group was significantly higher than the negative control (NC). The viable cells of the mimic group were significantly lower than the NC. In contrast, inhibition of miR-7 had the opposite effect.3. The dual-luciferase assay showed that the KLF4 was a target gene of miR-7. The rescue experiment showed that the KLF4 gene could attenuate the effect of miR-7 on the expression of apoptosis marker genes in CPMs.4. Determination of the function the KLF4 gene showed that the expression of the apoptosis marker genes in CPMs decreased significantly compared with the NC after its overexpression. Inhibition of KLF4 gene had the opposite effect. Flow cytometry showed that overexpression of the KLF4 gene inhibited early apoptosis of myoblasts (P ≤ 0.01), while interference with the KLF4 gene could promote early apoptosis of myoblasts (P ≤ 0.001).5. The results demonstrated, for the first time, that miR-7 promotes apoptosis in chicken primary myoblasts by regulating the expression of the KLF4 gene.

Upregulation of MicroRNA-199 (miR-199) Prompts the Apoptosis of K562 Cell in the Model of Mice with Leukemia

We investigated miR-199’s effect on the apoptosis of leukemia cells (K562) as so to provide reference idea for a new therapeutic target. 20 normal and healthy BALB/c nude rats were selected and equally and randomly assigned into inoculated group and blank group. The K562 cell was obtained and then divided into blank control group, miR-199 mimic group, and miR-199NC group followed by analysis of miR-199 expression, cell activity and apoptosis as well as the expression of Bax, Bcl-2 and PCNA. Inoculated group showed significantly higher proportion of leukemia cells and myeloid cells than blank group. The expression of miR-199 (3.22±0.03) in miR-199 mimic group was significantly higher than other two groups (P < 0.05) without difference between other two groups (P > 0.05). Bax expression (1.16±0.10) in miR-199 mimic group was significantly higher, whereas Bcl-2 (0.02±0.01) and PCNA (0.47±0.05) expression was significantly lower than other two groups. Upregulation of miR-199 could restrain the expression of Bcl-2 and PCNA through upregulation of Bax, indicating that miR-199 might be a new therapeutic target.

t(8;21) Acute Myeloid Leukemia as a Paradigm for the Understanding of Leukemogenesis at the Level of Gene Regulation and Chromatin Programming

Acute myeloid leukemia (AML) is a heterogenous disease with multiple sub-types which are defined by different somatic mutations that cause blood cell differentiation to go astray. Mutations occur in genes encoding members of the cellular machinery controlling transcription and chromatin structure, including transcription factors, chromatin modifiers, DNA-methyltransferases, but also signaling molecules that activate inducible transcription factors controlling gene expression and cell growth. Mutant cells in AML patients are unable to differentiate and adopt new identities that are shaped by the original driver mutation and by rewiring their gene regulatory networks into regulatory phenotypes with enhanced fitness. One of the best-studied AML-subtypes is the t(8;21) AML which carries a translocation fusing the DNA-binding domain of the hematopoietic master regulator RUNX1 to the ETO gene. The resulting oncoprotein, RUNX1/ETO has been studied for decades, both at the biochemical but also at the systems biology level. It functions as a dominant-negative version of RUNX1 and interferes with multiple cellular processes associated with myeloid differentiation, growth regulation and genome stability. In this review, we summarize our current knowledge of how this protein reprograms normal into malignant cells and how our current knowledge could be harnessed to treat the disease.

Inducible transgene expression in PDX models in vivo identifies KLF4 as a therapeutic target for B-ALL

Background

Clinically relevant methods are not available that prioritize and validate potential therapeutic targets for individual tumors, from the vast amount of tumor descriptive expression data.

Methods

We established inducible transgene expression in clinically relevant patient-derived xenograft (PDX) models in vivo to fill this gap.

Results

With this technique at hand, we analyzed the role of the transcription factor Krüppel-like factor 4 (KLF4) in B-cell acute lymphoblastic leukemia (B-ALL) PDX models at different disease stages. In competitive preclinical in vivo trials, we found that re-expression of wild type KLF4 reduced the leukemia load in PDX models of B-ALL, with the strongest effects being observed after conventional chemotherapy in minimal residual disease (MRD). A nonfunctional KLF4 mutant had no effect on this model. The re-expression of KLF4 sensitized tumor cells in the PDX model towards systemic chemotherapy in vivo. It is of major translational relevance that azacitidine upregulated KLF4 levels in the PDX model and a KLF4 knockout reduced azacitidine-induced cell death, suggesting that azacitidine can regulate KLF4 re-expression. These results support the application of azacitidine in patients with B-ALL as a therapeutic option to regulate KLF4.

Conclusion

Genetic engineering of PDX models allows the examination of the function of dysregulated genes like KLF4 in a highly clinically relevant translational context, and it also enables the selection of therapeutic targets in individual tumors and links their functions to clinically available drugs, which will facilitate personalized treatment in the future.

Increased expression of RUNX1 in clear cell renal cell carcinoma predicts poor prognosis

Background

Runt-related transcription factor 1 (RUNX1) was previously reported to play a dual role in promoting or suppressing tumorigenesis in various malignancies. A public dataset from The Cancer Genome Atlas (TCGA) was used to evaluate the role of RUNX1 in clear cell renal cell carcinoma (ccRCC).

Methods

The Wilcoxon signed-rank test was used to compare the expression of RUNX1 in ccRCC tissues and normal tissues. The Wilcoxon signed-rank test and logistic regression were utilized to investigate the relationship between clinicopathological factors and RUNX1 expression. Additionally, we analysed the differences in prognosis between patients with high and low expression of RUNX1 via the Kaplan–Meier method and Cox regression. Gene set enrichment analysis (GSEA) was performed to explore the mechanisms of RUNX1 in ccRCC.

Results

The expression of RUNX1 in ccRCC tissues was significantly higher than that in normal tissues. High expression of RUNX1 was significantly associated with gender (p = 0.003), clinical stage (p < 0.001), tissue infiltration (p < 0.001), lymph node metastasis (p = 0.037) and histological grade (p < 0.001). Logistic regression analysis showed that high RUNX1 expression was significantly correlated with gender (OR = 1.71 for male vs. female, p = 0.004), histological grade (OR = 11.61 for grade IV vs. I, p < 0.001), clinical stage (OR = 1.55 for stage III/IV vs. I/II, p = 0.014) and tissue infiltration (OR = 1.54 for positive vs. negative, p = 0.018). Kaplan–Meier survival curves revealed that the prognosis of patients with ccRCC with high RUNX1 expression was worse than that of patients with ccRCC with low RUNX1 expression (p < 0.001). Univariate Cox regression analysis showed that high RUNX1 expression was strongly correlated with poor prognosis (HR = 1.60, 95% CI [1.31–1.97], p < 0.001). In addition, high expression of RUNX1 was an independent prognostic factor for poor overall survival (OS), with an HR of 1.50 (95% CI [1.20–1.87], p < 0.001) in multivariate Cox analysis. GSEA showed that the apoptosis, B cell receptor signalling pathway, calcium signalling pathway, chemokine signalling pathway, JAK/STAT signalling pathway, MAPK signalling pathway, p53 signalling pathway, pathways in cancer, T cell receptor signalling pathway, Toll-like receptor signalling pathway, VEGF signalling pathway, and Wnt signalling pathway were significantly enriched in the RUNX1 high-expression phenotype. In conclusion, RUNX1 can be used as a novel prognostic factor and therapeutic target in ccRCC.