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Background: Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive types of solid tumor, and novel strategies must be developed for treating it. Previous studies predominantly utilized circular RNA (circRNA) expression plasmids incorporating Alu elements to facilitate the indirect expression of circRNA. Methods: Public databases and bioinformatics tools were used to identify hsa_circ_0004781 that is highly expressed in PDAC and its potential microRNA (miRNA) targets and corresponding mRNA targets. Real hsa_circ_0004781, which is identical to the native form of hsa_circ_0004781 without any exogenous sequences, was prepared through in vitro transcription by using a ribozyme and ion-pair reversed-phase high-performance liquid chromatography (IP-RP HPLC). The biological functions of hsa_circ_0004781 were evaluated using loss-of-function and gain-of-function approaches with circRNA expression plasmids and real hsa_circ_0004781. Results: Knockdown of hsa_circ_0004781 inhibited the proliferation and migration of PDAC cells, whereas its overexpression produced opposite effects. Hsa_circ_0004781 was identified as a sponge for miR-9-5p and miR-338-3p, and its expression was negatively correlated with that of these miRNAs. Among the targets of miR-9-5p and miR-338-3p, Kruppel-like factor 5 (KLF5) and a disintegrin and metalloproteinase domain 17 (ADAM17) were negatively correlated with survival in patients with PDAC and were inversely regulated by these miRNAs. Furthermore, real hsa_circ_0004781 exhibited the same effects as those of the circRNA expression plasmids. Conclusions: This study is the first to use real circRNAs to validate results obtained using circRNA expression plasmids. The results suggest that hsa_circ_0004781 functions as an oncogene, promoting the proliferation of PDAC cells through the miR-9-5p/KLF5 and miR-338-3p/ADAM17 axes. Therefore, hsa_circ_0004781 might be a therapeutic target for PDAC. [ABSTRACT FROM AUTHOR]

Inhibiting the androgen receptor (AR) is effective for treatment of advanced prostate cancers because of their AR-dependent luminal epithelial cell identity. Tumors progress during therapy to castration-resistant prostate cancer (CRPC) by restoring AR signaling and maintaining luminal identity or by converting through lineage plasticity to a neuroendocrine (NE) identity or double-negative CRPC (DNPC) lacking luminal or NE identities. Here, we show that DNPC cells express genes defining basal, club, and hillock epithelial cells from benign prostate. We identified KLF5 as a regulator of genes defining this mixed basal, club, and hillock cell identity in DNPC models. KLF5-mediated upregulation of RARG uncovered a DNPC sensitivity to growth inhibition by retinoic acid receptor agonists, which down-regulated KLF5 and up-regulated AR. These findings offer CRPC classifications based on prostate epithelial cell identities and nominate KLF5 and RARG as therapeutic targets for CRPC displaying a mixed basal, club, and hillock identity. [ABSTRACT FROM AUTHOR]

Objective: Esophageal squamous cell carcinoma (ESCC) has high morbidity and mortality in developing countries. The purpose of this article is to study the mechanism of KLF5's effect on ESCC radiosensitivity. Methods: WGCNA gene expression profiling identified core genes associated with ESCC radiosensitivity. KLF5 expression was detected by RT-qPCR. The effects of overexpression or downregulation of KLF5 on anti-irradiated cells' proliferation, migration, invasion, and apoptotic activity were studied through colony formation assay, Transwell assay, and flow cytometry. Western blot can detect the activity of Nrf2 signaling pathway in cells and tissues. The enrichment of KLF5 at the Keap1 promoter was analyzed by ChIP-base, and the binding of KLF5 to Keap1 was analyzed by ChIP and dual-luciferase. They then injected ESCC cells into mice and used radiation to monitor tumor progression. Results: KLF5 is a core gene in ESCC and is significantly associated with radiosensitivity. KLF5 expression is upregulated in drug-resistant ESCC cells. Overexpression of KLF5 significantly increased cell viability and attenuated cellular responses to radiation. KLF5 knockdown reduces radioresistance. After KLF5 overexpression, the Nrf2 signaling pathway was significantly up-regulated, and after KLF5 was up-regulated, the Keap1 signaling pathway was down-regulated. KLF5 inhibits the transcriptional activity of Keap1. Upregulation of Keap1 inhibits the effect of KLF5 overexpression on radioresistance of ESCC cells. KLF5/Keap1 regulates the effects of ESCC on in vivo radiotherapy. Conclusion: KLF5 promotes ESCC radioresistance by inhibiting Keap1 transcription and activating the Nrf2 pathway. [ABSTRACT FROM AUTHOR]

The overexpression of Kruppel-like factor 5 (KLF5) appears in several types of cancer. KLF5 may be an effective therapeutic target for treating OC, but its function in ovarian cancer (OC) remains unknown. The KLF5 mRNA expression levels in several OC cell lines were analyzed using RT-qPCR. Then, NC-siRNA or KLF5-siRNA was transfected into SK-OV-3 and OVCAR-3 cells. RT-qPCR and WB were used to detect the efficiency of KLF5 silence, CCK-8, colony formation assay, IHC staining, flow cytometry, and WB were performed to investigate the KLF5 function on OC cell proliferation and the activation of the extracellular signal-regulated Kinase (ERK)/mitogen-activated protein kinase (MAPK) signaling pathway. Next, a dual-luciferase and IF assay were used to determine the relationship between KLF5 and the Ras response element-binding protein (RREB1). SK-OV-3 and OVCAR-3 cells were treated with KLF5-siRNA and C16-PAF + EGF (MAPK agonist), separately or in combination. Proteins including KLF5, RREB1, p-p38, p-ERK1/2, ERK5, p-ERK5, Cyclin D1, CDK4, and CDK6 were quantified by WB. Finally, CCK-8, colony formation assay, and flow cytometry were employed again. KLF5 is highly expressed in OC cells compared with normal cells. When KLF5 knockdowns in SK-OV-3 and OVCAR-3 cells, the cell proliferation restrains, and the G1 phase prolongs. In addition, KLF5 silence caused a decrease of Cyclin D1, CDK4, CDK6, p-p38, p-ERK1/2, and p-ERK5/ERK5 expression levels. However, these statuses could be revised by C16-PAF + EGF. Results also found that when the ERK/MAPK signaling is activating, RREB1 is expressed low. The KLF5 silence could up-regulate the RREB1 expression. The KLF5 silence could restrain the OC cell proliferation and cell cycle. KLF5-siRNA may target upregulating RREB1 expression, thereby inhibiting the activation of the ERK/MAPK signaling pathway in OC cells. [ABSTRACT FROM AUTHOR]

Background and Purpose Experimental Approach Key Results Conclusions and Implications Cardiac glycosides (CGs), traditionally prescribed for heart failure and arrhythmias, show anticancer potential. However, their mechanisms for preferential inhibition of tumour tissue and constituent malignant cells are not fully elucidated. This study aims to elucidate the therapeutic benefits of CGs in targeting specific tumours and dissect their multi‐targeting mechanisms that confer their cytotoxicity against malignant cells.We designed an integrated workflow to identify therapeutic CGs with high toxicity to certain cancers, investigating their multi‐target effects, assessing their toxicity to malignant cells and analysing the prognostic relevance of CGs' target genes. The computational findings were confirmed through gene knockdown, cell viability assays, reactive oxygen species (ROS) measurements and so forth.CGs modulate multiple genes crucial for ion homeostasis, oxidative stress and apoptosis, with a particularly strong inhibitory effects on uveal melanoma (UVM). Notably, digitoxin suppresses UVM cell proliferation and induces ROS levels by simultaneously targeting STAT3 and KLF5. Single‐cell transcriptomic analysis revealed that malignant cells are likely more vulnerable to CGs due to their higher expression of CG target genes compared with surrounding cells in the UVM microenvironment.Given UVM's limited options, our study highlights the potential of digitoxin as a promising novel therapeutic agent for this aggressive and rare ocular cancer. Our comprehensive approach is effective in identifying the potent, cancer‐specific therapeutic agents from herbal plants. [ABSTRACT FROM AUTHOR]

Abstract Objective Esophageal squamous cell carcinoma (ESCC) has high morbidity and mortality in developing countries. The purpose of this article is to study the mechanism of KLF5's effect on ESCC radiosensitivity. Methods WGCNA gene expression profiling identified core genes associated with ESCC radiosensitivity. KLF5 expression was detected by RT-qPCR. The effects of overexpression or downregulation of KLF5 on anti-irradiated cells' proliferation, migration, invasion, and apoptotic activity were studied through colony formation assay, Transwell assay, and flow cytometry. Western blot can detect the activity of Nrf2 signaling pathway in cells and tissues. The enrichment of KLF5 at the Keap1 promoter was analyzed by ChIP-base, and the binding of KLF5 to Keap1 was analyzed by ChIP and dual-luciferase. They then injected ESCC cells into mice and used radiation to monitor tumor progression. Results KLF5 is a core gene in ESCC and is significantly associated with radiosensitivity. KLF5 expression is upregulated in drug-resistant ESCC cells. Overexpression of KLF5 significantly increased cell viability and attenuated cellular responses to radiation. KLF5 knockdown reduces radioresistance. After KLF5 overexpression, the Nrf2 signaling pathway was significantly up-regulated, and after KLF5 was up-regulated, the Keap1 signaling pathway was down-regulated. KLF5 inhibits the transcriptional activity of Keap1. Upregulation of Keap1 inhibits the effect of KLF5 overexpression on radioresistance of ESCC cells. KLF5/Keap1 regulates the effects of ESCC on in vivo radiotherapy. Conclusion KLF5 promotes ESCC radioresistance by inhibiting Keap1 transcription and activating the Nrf2 pathway.

Pancreatic cancer (PC) is characterized by a high relapse rate and unfavorable prognosis. Currently, the optimal treatment for PC is complete resection followed by adjuvant systemic chemotherapy. Nevertheless, tumor cell repopulation and subsequent tumor relapse and metastasis after chemotherapy result in a poor prognosis. Therefore, it is of great value to explore the potential molecular mechanisms underlying PC for developing novel treatment strategies. Herein, we aimed to investigate the potential regulatory mechanism of miR-1305 upon aerobic proliferation, metastasis, and apoptosis in PC. miR-1305 was downregulated in PC tissues and cell lines. miR-1305 overexpression prominently inhibited PC cell proliferation and metastasis promoted cell apoptosis in vitro, and alleviated PC formation in vivo. As predicted, KLF5 could directly bind to miR-1305. Silencing of KLF5 or KLF5 inhibitor (ML264) suppressed PC cell viability and cell invasion, and enhanced cell apoptosis. KLF5 restrained miR-1305 transcription and expression by binding to its promoter region. miR-1305 exerted a suppressive effect on PC cell proliferation and apoptosis via regulation of the KLF5-ERBB2 axis; KLF5 gene is a transcriptional regulator of miR-1305, promising to be a new target for the diagnosis and treatment of PC. [ABSTRACT FROM AUTHOR]

Abstract Background Triple-negative breast cancer (TNBC) is currently the most aggressive subtype of breast cancer, characterized by high heterogeneity and strong invasiveness, and currently lacks effective therapies. PRMT5, a type II protein arginine methyltransferase, is upregulated in numerous cancers, including TNBC, and plays a critical role, marked it as an attractive therapeutic target. PROTAC (Proteolysis Targeting Chimeras) is an innovative drug development technology that utilizes the ubiquitin-proteasome system (UPS) to degrade target proteins, which is characterized by higher activity, enhanced safety, lower resistance, and reduced toxicity, offering significant value for clinical translation. Methods This study utilizes the PROTAC technology to develop potential degraders targeting PRMT5 in vitro and in vivo. Results Through the design, synthesis and screening of a series of targeted compounds, we identified YZ-836P as an effective compound that exerted cytotoxic effects and reduced the protein levels of PRMT5 and its key downstream target protein KLF5 in TNBC after 48 h. Its efficacy was significantly superior to the PRMT5 PROTAC degraders that had been reported. YZ-836P induced G1 phase cell cycle arrest and significantly induced apoptosis in TNBC cells. Additionally, we demonstrated that YZ-836P promoted the ubiquitination and degradation of PRMT5 in a cereblon (CRBN)-dependent manner. Notably, YZ-836P exhibited pronounced efficacy in inhibiting the growth of TNBC patient-derived organoids and xenografts in nude mice. Conclusions These findings position YZ-836P as a promising candidate for advancing treatment modalities for TNBC. Trial registration Ethics Committee of Yunnan Cancer Hospital, KYCS2023-078. Registered 7 June 2023.

Abstract Circular RNA (circRNA), a stable ring‐shaped RNA molecule found in eukaryotic cells, plays significant roles in biological regulation, particularly by interfering with transcription factor binding or enhancing gene expression. Using transcriptomic sequencing, we identified differentially expressed circRNAs in bovine muscle at various time points. Specifically, circDYRK1A was discovered and shown to enhance differentiation while suppressing proliferation of adult myoblasts. Rescue experiments further demonstrated that circDYRK1A regulates the KLF5 gene expression by interacting with miR21‐5p, thus exerting its influence at the transcriptional level. This study marks the first identification of circDYRK1A in cattle and elucidates its role in bovine myoblast development through the circDYRK1A‐miR21‐5p‐KLF5 regulatory axis. These findings contribute novel insights into molecular breeding of cattle and advance fundamental research on beef cattle breeding and muscle development.

Abstract Lung adenocarcinoma (LUAD) is the most important subtype of lung cancer. It is well known that the gut microbiome plays an important role in the pathophysiology of various diseases, including cancer, but little research has been done on the intestinal microbiome associated with LUAD. Utilizing bioinformatics tools and data analysis, we identified novel potential prognostic biomarkers for LUAD. To integrate differentially expressed genes and clinical significance modules, we used a weighted correlation network analysis system. According to the Peryton database and the gutMGene database, the composition and structure of gut microbiota in LUAD patients differed from those in healthy individuals. LUAD was associated with 150 gut microbiota and 767 gut microbiota targets, with Krüppel-like factor 5 (KLF5) being the most closely related. KLF5 was associated with immune status and correlated well with the prognosis of LUAD patients. The identification of KLF5 as a potential prognostic biomarker suggests its utility in improving risk stratification and guiding personalized treatment strategies for LUAD patients. Altogether, KLF5 could be a potential prognostic biomarker in LUAD. Graphical Abstract

Background: Triple-negative breast cancer (TNBC) is currently the most aggressive subtype of breast cancer, characterized by high heterogeneity and strong invasiveness, and currently lacks effective therapies. PRMT5, a type II protein arginine methyltransferase, is upregulated in numerous cancers, including TNBC, and plays a critical role, marked it as an attractive therapeutic target. PROTAC (Proteolysis Targeting Chimeras) is an innovative drug development technology that utilizes the ubiquitin-proteasome system (UPS) to degrade target proteins, which is characterized by higher activity, enhanced safety, lower resistance, and reduced toxicity, offering significant value for clinical translation. Methods: This study utilizes the PROTAC technology to develop potential degraders targeting PRMT5 in vitro and in vivo. Results: Through the design, synthesis and screening of a series of targeted compounds, we identified YZ-836P as an effective compound that exerted cytotoxic effects and reduced the protein levels of PRMT5 and its key downstream target protein KLF5 in TNBC after 48 h. Its efficacy was significantly superior to the PRMT5 PROTAC degraders that had been reported. YZ-836P induced G1 phase cell cycle arrest and significantly induced apoptosis in TNBC cells. Additionally, we demonstrated that YZ-836P promoted the ubiquitination and degradation of PRMT5 in a cereblon (CRBN)-dependent manner. Notably, YZ-836P exhibited pronounced efficacy in inhibiting the growth of TNBC patient-derived organoids and xenografts in nude mice. Conclusions: These findings position YZ-836P as a promising candidate for advancing treatment modalities for TNBC. Trial registration: Ethics Committee of Yunnan Cancer Hospital, KYCS2023-078. Registered 7 June 2023. [ABSTRACT FROM AUTHOR]

Aim: Vascular smooth muscle cell (VSMC) phenotypic switching has been reported to regulate vascular function and thoracic aortic aneurysm and dissection (TAAD) progression. Early growth response 1 (Egr1) is associated with the differentiation of VSMCs. However, the mechanisms through which Egr1 participates in the regulation of VSMCs and progression of TAAD remain unknown. This study aimed to investigate the role of Egr1 in the phenotypic switching of VSMCs and the development of TAAD. Methods: Wild‐type C57BL/6 and SMC‐specific Egr1‐knockout mice were used as experimental subjects and fed β‐aminopropionitrile for 4 weeks to construct the TAAD model. Ultrasound and aortic staining were performed to examine the pathological features in thoracic aortic tissues. Transwell, wound healing, CCK8, and immunofluorescence assays detected the migration and proliferation of synthetic VSMCs. Egr1 was directly bound to the promoter of Krüppel‐like factor 5 (KLF5) and promoted the expression of KLF5, which was validated by JASPAR database and dual‐luciferase reporter assay. Results: Egr1 expression increased and was partially co‐located with VSMCs in aortic tissues of mice with TAAD. SMC‐specific Egr1 deficiency alleviated TAAD and inhibited the phenotypic switching of VSMC. Egr1 knockdown prevented the phenotypic switching of VSMCs and subsequently suppressed the migration and proliferation of synthetic VSMCs. The inhibitory effects of Egr1 deficiency on VSMCs were blunted once KLF5 was overexpressed. Conclusion: Egr1 aggravated the development of TAAD by promoting the phenotypic switching of VSMCs via enhancing the transcriptional activation of KLF5. These results suggest that inhibition of SMC‐specific Egr1 expression is a promising therapy for TAAD. [ABSTRACT FROM AUTHOR]

Glycolysis is one of the key metabolic reprogramming characteristics of ovarian cancer. Ursolic Acid (UA), as a natural compound, exerts a beneficial regulatory effect on tumor metabolism. In this study, we have confirmed through RNA-seq analysis and a series of in vitro and in vivo functional experiments that UA significantly inhibits ovarian cancer cell proliferation, promotes tumor apoptosis, and reduces glycolysis levels. Additionally, it demonstrates synergistic therapeutic effects with cisplatin in both in vitro and in vivo experiments. Furthermore, at the molecular level, we found that UA inhibits glycolysis in ovarian cancer by binding to the transcription factor KLF5 and blocking the transcriptional expression of the downstream PI3K/AKT signaling pathway, thereby exerting its therapeutic effect. In conclusion, our research indicates that UA can inhibit the proliferation, apoptosis, and glycolysis levels of ovarian cancer cells through the KLF5/PI3K/AKT signaling axis. Our findings offer a new perspective on the therapeutic application of the natural compound UA in ovarian cancer and support its potential development as a candidate for chemotherapy. [ABSTRACT FROM AUTHOR]

Diagnostic and prognostic values of Kruppel-like factor 5 (KLF5) and Runt-related transcription factor 1 (RUNX1) were determined in sepsis-induced acute kidney injury (SI-AKI). The study included 120 septic patients and set two groups: SI-AKI group (n = 60) or non-AKI group (n = 60). Fasting venous blood was drawn, and KLF5 and RUNX1 levels were measured. The receiver operating characteristic curve was plotted for diagnostic evaluation of KLF5 and RUNX1 in SI-AKI. The correlation between KLF5 and RUNX1 and serum creatinine (Scr), cystatin C (Cys-C), and kidney injury molecule 1 (KIM-1) were assessed by Pearson method. Predictive values of KLF5 and RUNX1 in 28-day survival of SI-AKI patients were considered by Kaplan-Meier survival curves and multivariate Cox regression analysis. Serum KLF5 and RUNX1 in SI-AKI patients were upregulated. Serum KLF5 and RUNX1 were of high diagnostic value in distinguishing SI-AKI patients from non-AKI patients. KLF5 and RUNX1 were in a positive correlation with Scr, Cys-C, and KIM-1, respectively. The 28-day survival of SI-AKI patients with high serum KLF5 or RUNX1 expression was poor, and serum KLF5 and RUNX1 expression were independently correlated with SI-AKI patients' survival. KLF5 and RUNX1 have diagnostic and prognostic values in SI-AKI patients. [ABSTRACT FROM AUTHOR]

Circular RNAs (circRNAs) play an important role in the progression of atherosclerosis (AS). This study aimed to explore the exact role and mechanism of circ_0002984 in oxidized low-density lipoprotein (ox-LDL)-mediated human vascular smooth muscle cells (HVSMCs). The model of smooth muscle cell phenotype switching was constructed by treating HVSMCs with ox-LDL. The levels of circ_0002984, let-7a-5p, and kruppel-like factor 5 (KLF5) were measured by quantitative real-time PCR or western blot assay. Cell proliferation, migration, and apoptosis were detected by Cell Counting Kit-8 (CCK-8), EdU staining, wound healing assay, transwell assay, and flow cytometry. The expression of cleaved-caspase-3 and KLF5 was examined by western blot. The relationship between let-7a-5p and circ_0002984 or KLF5 was verified by dual-luciferase reporter assay or RIP assay. The results showed that circ_0002984 and KLF5 were up-regulated, while let-7a-5p was down-regulated in AS patients and ox-LDL-disposed HVSMCs. Silence of circ_0002984 suppressed proliferation and migration, and promoted apoptosis in ox-LDL-stimulated HVSMCs. Moreover, circ_0002984 sponged let-7a-5p to regulate the proliferation, migration, and apoptosis in ox-LDL-resulted HVSMCs. In addition, KLF5 was a target of let-7a-5p and its overexpression reversed the effect of let-7a-5p on the proliferation, migration, and apoptosis in ox-LDL-treated HVSMCs. Also, circ_0002984 positively regulated KLF5 expression by absorbing let-7a-5p. The promotion effect of circ_0002984 on the proliferation and migration of ox-LDL-treated HVSMCs was reversed by KLF5 silencing. Taken together, depletion of circ_0002984 inhibited the proliferation and migration of ox-LDL-stimulated HVSMCs, which might be achieved by modulating the let-7a-5p/KLF5 axis. [ABSTRACT FROM AUTHOR]

Pancreatic Ductal AdenoCarcinoma (PDAC) is characterized by a poor prognosis and is poorly amenable to modern therapies. A range of cell cultures reflecting different degrees of tumor differentiation and malignancy can serve as a model of PDAC development. Highly differentiated cells with low malignancy are characterized by increased expression of the KLF5 gene. The KLF5 protein is a vivid representative of multifunctional transcription factors, and its involvement in a variety of cellular processes, particularly in the pathology of various cancers, has been demonstrated. We investigated the spatial organization of chromatin of the regulatory regions of the KLF5 gene using highly differentiated Capan2 PDAC cells with a high level of KLF5 expression and poorly differentiated MIA PaCa2 PDAC cells with a low level of expression of this gene by circular chromosome conformation capture (4C-seq). It was shown that the number and distribution of contacts of the KLF5 regulatory region with other chromatin regions are significantly different for these types of cells; the number of contacts is significantly higher for Capan2 cells. There is a correlation between the expression level of genes close to KLF5 and the intensity of their sequence contacts with the KLF5 regulatory region, indicating that their expression is coordinated, possibly within the transcriptional factory. Capan2 is characterized by a high level of contacts of the KLF5 regulatory region with the gene-free region containing a cluster of PDAC-associated single nucleotide polymorphisms (SNP/InDel). Thus, the total number of contacts of the promoter region of the KLF5 gene and the expression level of most of the surrounding KLF5 genes decrease as the grade of cell malignancy increases. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the underlying mechanism of miR-9-5p in airway smooth muscle cells (ASMCs) of asthmatic mice. An asthmatic mouse model was established through the intraperitoneal injection of ovalbumin. Histopathological changes in lung tissues of asthmatic mice were observed using HE staining. ASMCs was identified using immunofluorescence staining and cell morphology. The mRNA expressions of miR-9-5p, KLF5, and IL-1β were measured using RT-qPCR. Additionally, CCK8 assay and flow cytometry were applied for ASMC proliferation and apoptosis, respectively. The protein levels of OPN, KLF5, and IL-1β were assessed using western blotting. The results showed that miR-9-5p was abnormally downregulated in lung tissues and ASMCs of asthmatic mice. Dual-Luciferase Reporter Assay and Chromatin immunoprecipitation confirmed that miR-9-5p targeted KLF5 that bounds to IL-1β promoter. Besides, miR-9-5p negatively regulated IL-1β mRNA and protein level via KLF5. Moreover, miR-9-5p was found to positively regulate ASMC apoptosis, negatively regulate ASMC proliferation and OPN protein expression, albeit with partial reversal by KLF5. Mechanistically, the regulation of ASMC proliferation and apoptosis by miR-9-5p is achieved by targeting KLF5/IL-1β axis. [ABSTRACT FROM AUTHOR]

Oesophageal squamous cell carcinoma (ESCC) contributes to high mortality. Modulating ferroptosis may reverse resistance to radiotherapy. This article was to explore the ubiquitination modification of KLF5 and its effect on ferroptosis in ESCC. KLF5 was under‐expressed by shRNA plasmids in the cells and ROS levels were analysed by flow cytometry, ferroptotic gene expression was detected by qRT‐PCR, MDA and GSH levels were determined by ELISA, cell morphology was observed by transmission electron microscopy, and Fe ion levels were analysed by immunofluorescence. Cells were treated with Ferrostatin‐1 and NAC and analysed for cell proliferation by colony formation assay, cell migration and invasion by Transwell assays, and apoptosis by flow cytometry. DNA damage in cells was also analysed using comet assay, EdU doping assay, γH2AX fluorescence, DNA‐PKcs and PCR. NEDD4L and KLF5 binding was analysed by immunoprecipitation. Changes in ferroptosis, DNA damage and resistance were analysed in cells with both silencing NEDD4L and KLF5. Changes in tumour resistance to radiation were analysed in mice underexpressing NEDD4L and KLF5. Low expression of KLF5 significantly promotes cellular lipid peroxidation levels, with decreased expression of SOD and GPX4, and increased expression of ACSL4. Concurrently, MDA levels deplete GSH, and cells exhibit typical ferroptotic morphology with increased Fe2+ content. KLF5 inhibition results in enhanced cellular clonogenicity, migration and invasion activities, reduced apoptosis, increased tail DNA, nuclear EdU incorporation, nuclear γH2AX foci and elevated expression of DNA‐PKcs, LIG4, RAD9B and BMI1. Ferrostatin‐1 and NAC reverse these effects. NEDD4L ubiquitination modifies and degrades KLF5, with NEDD4L/KLF5 inhibition mitigating cellular ferroptosis and DNA damage, thereby promoting radiosensitivity both in vitro and in vivo. NEDD4L increases radiosensitivity by accelerating cellular ferroptosis via ubiquitination modification of KLF5. [ABSTRACT FROM AUTHOR]

Lung adenocarcinoma (LUAD) is the most important subtype of lung cancer. It is well known that the gut microbiome plays an important role in the pathophysiology of various diseases, including cancer, but little research has been done on the intestinal microbiome associated with LUAD. Utilizing bioinformatics tools and data analysis, we identified novel potential prognostic biomarkers for LUAD. To integrate differentially expressed genes and clinical significance modules, we used a weighted correlation network analysis system. According to the Peryton database and the gutMGene database, the composition and structure of gut microbiota in LUAD patients differed from those in healthy individuals. LUAD was associated with 150 gut microbiota and 767 gut microbiota targets, with Krüppel-like factor 5 (KLF5) being the most closely related. KLF5 was associated with immune status and correlated well with the prognosis of LUAD patients. The identification of KLF5 as a potential prognostic biomarker suggests its utility in improving risk stratification and guiding personalized treatment strategies for LUAD patients. Altogether, KLF5 could be a potential prognostic biomarker in LUAD. [ABSTRACT FROM AUTHOR]

Myocardial fibrosis (MF), which is an inevitable pathological manifestation of many cardiovascular diseases in the terminal stage, often contributes to severe cardiac dysfunction and sudden death. Morroniside (MOR) is the main active component of Cornus officinalis with a variety of biological activities. This study was designed to explore the efficacy of MOR in MF and to investigate its pharmacological mechanism. The viability of MOR-treated human cardiac fibroblast (HCF) cells with or without Angiotensin II (AngII) induction was assessed with Cell Counting Kit-8 (CCK-8). The migration of AngII-induced HCF cells was appraised with a transwell assay. Gelatin zymography analysis was adopted to evaluate the activities of MMP2 and MMP9, while immunofluorescence assay was applied for the estimation of Collagen I and Collagen III. By means of western blot, the expressions of migration-, fibrosis-, and p38/c-Jun N-terminal kinase (JNK) signal pathway-related proteins were resolved. The transfection efficacy of oe-Kruppel-like factor 5 (KLF5) was examined with reverse transcription-quantitative PCR (RT-qPCR) and western blot. In this study, it was found that MOR treatment inhibited AngII-induced hyperproliferation, migration, and fibrosis of HCF cells, accompanied with decreased activities of matrix metalloproteinase 2 (MMP2), matrix metalloproteinase 9 (MMP9), connective tissue growth factor (CTGF), Fibronectin, and α-SMA, which were all reversed by KLF5 overexpression. Collectively, MOR exerted protective effects on MF by blocking p38/JNK signal pathway through the downregulation of KLF5. [ABSTRACT FROM AUTHOR]

Aim This study explored the effect and mechanism of MAFF and HDAC6 on renal fibrosis and inflammation in lupus nephritis (LN).Methods IL-33 treated renal epithelial cells and MRL/lpr mice were respectively used for in vitro and in vivo experiments. The expressions of HDAC6, MAFF, and KLF5 were measured in cells and renal tissues. Before and after cell transfection, the morphological changes in renal tissues were observed using Hematoxylin and eosin (H&E) and Masson staining. The proteinuria, serum creatinine (SCr), blood urea nitrogen (BUN), and double-stranded DNA (dsDNA) levels were detected by biochemical analysis. The expressions of fibrosis and inflammation related proteins (including α-SMA, Vimentin, IL-1β, IL-6, and TNF-α), p65, and iNOS were also detected. The relationship among MAFF, HDAC6, and KLF5 was determined by chromatin immunoprecipitation and dual luciferase reporter gene assay.Results Renal tissues and cell models had elevated expressions of HDAC6 and KLF5, and decreased MAFF expression. HDAC6 suppression or MAFF overexpression led to suppression of proteinuria, SCr, BUN, and dsDNA levels, as well as attenuation of inflammatory infiltration and collagen deposition. HDAC6 can suppress MAFF expression via deacetylation to abolish its suppression of KLF5 expression, thus increasing KLF5 expression. In vivo and in vitro experiments showed the suppressive effect of HDAC6 suppression on renal fibrosis and inflammation can be abolished by KLF5 overexpression.Conclusion HDAC6 suppresses MAFF expression via deacetylation to elevate KLF5 expression, which consequently enhances fibrosis and inflammatory response in LN.

Abstract Background Increasing evidence shows the pivotal significance of miRNAs in the pathogenesis of osteoporosis. miR-381-3p has been identified as an inhibitor of osteogenesis. This study explored the role and mechanism of miR-381-3p in postmenopausal osteoporosis (PMOP), the most common type of osteoporosis. Methods Bilateral ovariectomy (OVX) rat model was established and miR-381-3p antagomir was administrated through the tail vein in vivo. The pathological changes in rats were assessed through the evaluation of serum bone turnover markers (BALP, PINP, and CTX-1), hematoxylin and eosin (H&E) staining, as well as the expression of osteoblast differentiation biomarkers. Moreover, isolated bone marrow mesenchymal stem cells from OVX-induced rats (OVX-BMMSCs) were utilized to explore the impact of miR-381-3p on osteoblast differentiation. In addition, the target gene and downstream pathway of miR-381-3p were further investigated both in vivo and in vitro. Results miR-381-3p expression was elevated, whereas KLF5 was suppressed in OVX rats. miR-381-3p antagomir decreased serum levels of bone turnover markers, improved trabecular separation, promoted osteoblast differentiation biomarker expression in OVX rats. ALP activity and mineralization were suppressed, and levels of osteoblast differentiation biomarkers were impeded after miR-381-3p overexpression during osteoblast differentiation of OVX-BMMSCs. While contrasting results were found after inhibition of miR-381-3p. miR-381-3p targets KLF5, negatively affecting its expression as well as its downstream Wnt/β-catenin pathway, both in vivo and in vitro. Silencing of KLF5 restored Wnt/β-catenin activation induced by miR-381-3p antagomir. Conclusion miR-381-3p aggravates PMOP by inhibiting osteogenic differentiation through targeting KLF5/Wnt/β-catenin pathway. miR-381-3p appears to be a promising candidate for therapeutic intervention in PMOP.

Background: Increasing evidence shows the pivotal significance of miRNAs in the pathogenesis of osteoporosis. miR-381-3p has been identified as an inhibitor of osteogenesis. This study explored the role and mechanism of miR-381-3p in postmenopausal osteoporosis (PMOP), the most common type of osteoporosis. Methods: Bilateral ovariectomy (OVX) rat model was established and miR-381-3p antagomir was administrated through the tail vein in vivo. The pathological changes in rats were assessed through the evaluation of serum bone turnover markers (BALP, PINP, and CTX-1), hematoxylin and eosin (H&E) staining, as well as the expression of osteoblast differentiation biomarkers. Moreover, isolated bone marrow mesenchymal stem cells from OVX-induced rats (OVX-BMMSCs) were utilized to explore the impact of miR-381-3p on osteoblast differentiation. In addition, the target gene and downstream pathway of miR-381-3p were further investigated both in vivo and in vitro. Results: miR-381-3p expression was elevated, whereas KLF5 was suppressed in OVX rats. miR-381-3p antagomir decreased serum levels of bone turnover markers, improved trabecular separation, promoted osteoblast differentiation biomarker expression in OVX rats. ALP activity and mineralization were suppressed, and levels of osteoblast differentiation biomarkers were impeded after miR-381-3p overexpression during osteoblast differentiation of OVX-BMMSCs. While contrasting results were found after inhibition of miR-381-3p. miR-381-3p targets KLF5, negatively affecting its expression as well as its downstream Wnt/β-catenin pathway, both in vivo and in vitro. Silencing of KLF5 restored Wnt/β-catenin activation induced by miR-381-3p antagomir. Conclusion: miR-381-3p aggravates PMOP by inhibiting osteogenic differentiation through targeting KLF5/Wnt/β-catenin pathway. miR-381-3p appears to be a promising candidate for therapeutic intervention in PMOP. [ABSTRACT FROM AUTHOR]

Abstract Background and objective Periodontitis is an inflammatory disease typically characterized by the destruction of periodontal tissues and complicated etiology. DNA methyltransferase 3A (DNMT3A) has been implicated in possessing pro-inflammatory properties. This study sought to explore the role of DNMT3A in periodontitis and its relevant mechanism. Methodology Lipopolysaccharide (LPS) was used to induce inflammation in human periodontal ligament stem cells (hPDLSCs). DNMT3A and KLF5 expressions were detected using RT-qPCR and western blot. The levels of inflammatory cytokines and inflammation-related proteins were detected using ELISA and western blot. NF-κB p65 expression was detected using immunofluorescence (IF) assay, while osteogenic differentiation was assessed using ALP assay and ARS staining. Western blot was used to measure the protein contents associated with osteogenic differentiation. DNMT3A activity was detected using luciferase report assay and chromatin immunoprecipitation (ChIP) was used to verify the interaction between KLF5 and DNMT3A. Results DNMT3A expression increased in LPS-induced hPDLSCs. Silencing DNMT3A suppressed the LPS-induced inflammation in hPDLSCs, while promoting osteogenic differentiation. It was also found that transcriptional factor KLF5 could bind to DNMT3A promoters and regulate DNMT3A expression. Rescue experiments showed that KLF5 interference partially counteracted the inhibitory impacts of DNMT3A deficiency on inflammation and the promotive effects on osteogenic differentiation in LPS-induced hPDLSCs. Conclusion DNMT3A, when transcriptionally downregulated by KLF5, could alleviate LPS-challenged inflammatory responses and facilitate osteogenic differentiation in hPDLSCs.

High levels of urinary lactate are an increased risk of progression in patients with diabetic kidney disease (DKD). However, it is still unveiled how lactate drive DKD. Epithelial-mesenchymal transition (EMT), which is characterized by the loss of epithelial cells polarity and cell-cell adhesion, and the acquisition of mesenchymal-like phenotypes, is widely recognized a critical contributor to DKD. Here, we found a switch from oxidative phosphorylation (OXPHOS) toward glycolysis in AGEs-induced renal tubular epithelial cells, thus leading to elevated levels of renal lactic acid. We demonstrated that reducing the lactate levels markedly delayed EMT progression and improved renal tubular fibrosis in DKD. Mechanically, we observed lactate increased the levels of histone H3 lysine 14 lactylation (H3K14la) in DKD. ChIP-seq & RNA-seq results showed histone lactylation contributed to EMT process by facilitating KLF5 expression. Moreover, KLF5 recognized the promotor of cdh1 and inhibited its transcription, which accelerated EMT of DKD. Additionally, nephro-specific knockdown and pharmacological inhibition of KLF5 diminished EMT development and attenuated DKD fibrosis. Thus, our study provides better understanding of epigenetic regulation of DKD pathogenesis, and new therapeutic strategy for DKD by disruption of the lactate-drived H3K14la/KLF5 pathway.

Sarcopenia is associated with progressive generalized skeletal muscle weakness, persistent decline in muscle strength, function, and quality of life in the elderly population. The presence of sarcopenia worsens the prognosis of older patients. In this regard, the study of the etiology and pathogenesis of sarcopenia, the identification of early markers for the diagnosis of this disease are relevant areas today. Myokines are secreted by skeletal muscle and play a important role in the regulation of muscle mass and function, metabolic homeostasis. Myokine synthesis disruption may contribute to the development of sarcopenia. In addition, we can see the polymorphism association of various genes with the development of the disease. This review brings together current knowledge about myokines and genetic factors as potential biomarkers for the early diagnosis of sarcopenia.

Abstract Objective Diabetic nephropathy (DN) manifests a critical aspect in the form of renal tubular injury. The current research aimed to determine the function and mechanism of long non-coding ribonucleic acid (LncRNA) differentiation antagonising non-protein coding RNA (DANCR), with a focus on its impact on renal tubular injury. Methods Quantitative reverse transcription polymerase chain reaction was employed to analyze the RNA levels of DANCR in the serum of patients with DN or human proximal tubular epithelial cells (human kidney 2 [HK2]). The diagnostic significance of DANCR was assessed using a receiver operating characteristic curve. A DN model was established by inducing HK-2 cells with high glucose (HG). Cell proliferation, apoptosis, and the levels of inflammatory factors, reactive oxygen species (ROS), and malondialdehyde (MDA) were detected using the Cell Counting Kit − 8, flow cytometry, and enzyme-linked immunosorbent assay. The interaction between microRNA (miR)-214-5p and DANCR or Krüppel-like factor 5 (KLF5) was investigated using RNA immunoprecipitation and dual-luciferase reporter assays. Results Elevated levels of DANCR were observed in the serum of patients with DN and HG-inducted HK-2 cells (P

Abstract Background Ossification of ligamentum flavum (OLF) is a prevalent degenerative spinal disease, typically causing severe neurological dysfunction. Kruppel-like factor 5 (KLF5) plays an essential role in the regulation of skeletal development. However, the mechanism KLF5 plays in OLF remains unclear, necessitating further investigative studies. Methods qRT-PCR, immunofluorescent staining and western blot were used to measure the expression of KLF5. Alkaline Phosphatase (ALP) staining, Alizarin red staining (ARS), and the expression of Runt-related transcription factor 2 (RUNX2), osteopontin (OPN), and osteocalcin (OCN) were used to evaluate the osteogenic differentiation. Luciferase activity assay and ChIP-PCR were performed to investigate the molecular mechanisms. Results KLF5 was significantly upregulated in OLF fibroblasts in contrast to normal ligamentum flavum (LF) fibroblasts. Silencing KLF5 diminished osteogenic markers and mineralized nodules, while its overexpression had the opposite effect, confirming KLF5’s role in promoting ossification. Moreover, KLF5 promotes the ossification of LF by activating the transcription of Connexin 43 (CX43), and overexpressing CX43 could reverse the suppressive impact of KLF5 knockdown on OLF fibroblasts’ osteogenesis. Conclusion KLF5 promotes the OLF by transcriptionally activating CX43. This finding contributes significantly to our understanding of OLF and may provide new therapeutic targets.

Abstract Background Ubiquitin carboxyl-terminal hydrolase L1 (UCHL1) is a deubiquitinating enzyme that regulates ERα expression in triple-negative cancer (TNBC). This study aimed to explore the deubiquitination substrates of UCHL1 related to endocrine therapeutic responses and the mechanisms of UCHL1 dysregulation in TNBC. Methods Bioinformatics analysis was conducted using online open databases. TNBC representative MDA-MB-468 and SUM149 cells were used for in vitro and in-vivo studies. Co-immunoprecipitation was used to explore the interaction between UCHL1 and KLF5 and UCHL1-mediated KIF5 deubiquitination. CCK-8, colony formation and animal studies were performed to assess endocrine therapy responses. The regulatory effect of TET1/3 on UCHL1 promoter methylation and transcription was performed by Bisulfite sequencing PCR and ChIP-qPCR. Results UCHL1 interacts with KLF5 and stabilizes KLF5 by reducing its polyubiquitination and proteasomal degradation. The UCHL1-KLF5 axis collaboratively upregulates EGFR expression while downregulating ESR1 expression at both mRNA and protein levels in TNBC. UCHL1 knockdown slows the proliferation of TNBC cells and sensitizes the tumor cells to Tamoxifen and Fulvestrant. KLF5 overexpression partially reverses these trends. Both TET1 and TET3 can bind to the UCHL1 promoter region, reducing methylation of associated CpG sites and enhancing UCHL1 transcription in TNBC cell lines. Additionally, TET1 and TET3 elevates KLF5 protein level in a UCHL1-dependent manner. Conclusion UCHL1 plays a pivotal role in TNBC by deubiquitinating and stabilizing KLF5, contributing to endocrine therapy resistance. TET1 and TET3 promote UCHL1 transcription through promoter demethylation and maintain KLF5 protein level in a UCHL1-dependent manner, implying their potential as therapeutic targets in TNBC.

Poly ADP-ribose polymerase (PARP) inhibitor monotherapies are selectively effective in patients with pancreatic, breast, prostate, and ovarian cancers with BRCA1 mutations. Cancer patients with more frequent wild-type BRCA show poor responses to PARP inhibitors. Moreover, patients who are initially sensitive to these inhibitors eventually respond poorly to drugs. In the present study, we discover that abrogation of Kruppel-like factor 5 (KLF5) significantly inhibits homologous recombination, which is the main mechanism for DNA double-stranded repair. Furthermore, the downregulation of KLF5 expression promotes the DNA damage induced by olaparib and significantly reduces the IC50 of the RARP inhibitor in pancreatic cancer cells. Overexpression of BRCA1 reverses the above effects caused by silencing of KLF5. Olaparib combined with a KLF5 inhibitor has an enhanced cytotoxic effect. Mechanistically, we identify BRCA1 as a KLF5 target gene. BRCA1 is positively correlated with KLF5 in PDAC tissue. Our results indicate that inhibition of KLF5 may induce BRCAness in a larger pancreatic cancer subset with proficient BRCA. The combination of KLF5 inhibitors and PARP inhibitors provides a novel treatment strategy to enhance the sensitivity of BRCA1-proficient pancreatic cancer to PARP inhibitors.

Background: Sevoflurane (Sevo) preconditioning and postconditioning play a protective role against injury induced by hepatic ischemia/reperfusion (I/R). At the same time, the involvement of macrophage infiltration in this process and the precise mechanisms are unclear. Here, we designed this research to elucidate the protective effects of Sevo against hepatic I/R injury and the molecules involved. Methods: The alleviating effect of Sevo on the liver injury was analyzed by liver function analysis, hematoxylin and eosin staining, Masson trichrome staining, terminal deoxynucleotidyl transferase‐mediated 2′‐deoxyuridine 5′‐triphosphate nick end labeling, western blot analysis and an enzyme‐linked immunosorbent assay. An in vitro cell model was developed using alpha mouse liver 12 (AML12) cells, and the cell model was treated with oxygen–glucose deprivation and reoxygenation and Sevo. Multiple bioinformatics databases were used to screen transcriptional regulators related to hepatic I/R injury and the targets of Krueppel‐like factor 5 (KLF5). KLF5 expression was artificially upregulated alone or with integrin beta‐2 (ITGB2) knockdown to substantiate their involvement in Sevo‐mediated hepatoprotection. Results: Sevo protected the liver against I/R injury by reducing cell apoptosis and inflammatory response. KLF5 was upregulated in liver tissues following I/R injury, whereas KLF5 overexpression aggravated macrophage infiltration and liver injury induced by I/R injury. KLF5 bound to the promoter of ITGB2 to enhance ITGB2 transcription. Knockdown of ITGB2 reversed the aggravation of injury caused by KLF5 overexpression in mice and AML12 cells. Conclusions: Sevo blocked KLF5‐mediated transcriptional activation of ITGB2, thereby inhibiting macrophage infiltration in hepatic I/R injury. [ABSTRACT FROM AUTHOR]

Objective: Diabetic nephropathy (DN) manifests a critical aspect in the form of renal tubular injury. The current research aimed to determine the function and mechanism of long non-coding ribonucleic acid (LncRNA) differentiation antagonising non-protein coding RNA (DANCR), with a focus on its impact on renal tubular injury. Methods: Quantitative reverse transcription polymerase chain reaction was employed to analyze the RNA levels of DANCR in the serum of patients with DN or human proximal tubular epithelial cells (human kidney 2 [HK2]). The diagnostic significance of DANCR was assessed using a receiver operating characteristic curve. A DN model was established by inducing HK-2 cells with high glucose (HG). Cell proliferation, apoptosis, and the levels of inflammatory factors, reactive oxygen species (ROS), and malondialdehyde (MDA) were detected using the Cell Counting Kit − 8, flow cytometry, and enzyme-linked immunosorbent assay. The interaction between microRNA (miR)-214-5p and DANCR or Krüppel-like factor 5 (KLF5) was investigated using RNA immunoprecipitation and dual-luciferase reporter assays. Results: Elevated levels of DANCR were observed in the serum of patients with DN and HG-inducted HK-2 cells (P < 0.05). DANCR levels effectively identified patients with DN from patients with type 2 diabetes mellitus. Silencing of DANCR protected against HG-induced tubular injury by restoring cell proliferation, inhibiting apoptosis, and reducing the secretion of inflammatory factors and oxidative stress production (P < 0.05). DANCR functions as a sponge for miR-214-5p, and the mitigation of DANCR silencing on HG-induced renal tubular injury was partially attenuated with reduced miR-214-5p (P < 0.05). Additionally, KLF5 was identified as the target of miR-214-5p. Conclusion: DANCR was identified as diagnostic potential for DN and the alleviation of renal tubular injury via the miR-214-5p/KLF5 axis, following DANCR silencing, introduces a novel perspective and approach to mitigating DN. [ABSTRACT FROM AUTHOR]

Background: Ubiquitin carboxyl-terminal hydrolase L1 (UCHL1) is a deubiquitinating enzyme that regulates ERα expression in triple-negative cancer (TNBC). This study aimed to explore the deubiquitination substrates of UCHL1 related to endocrine therapeutic responses and the mechanisms of UCHL1 dysregulation in TNBC. Methods: Bioinformatics analysis was conducted using online open databases. TNBC representative MDA-MB-468 and SUM149 cells were used for in vitro and in-vivo studies. Co-immunoprecipitation was used to explore the interaction between UCHL1 and KLF5 and UCHL1-mediated KIF5 deubiquitination. CCK-8, colony formation and animal studies were performed to assess endocrine therapy responses. The regulatory effect of TET1/3 on UCHL1 promoter methylation and transcription was performed by Bisulfite sequencing PCR and ChIP-qPCR. Results: UCHL1 interacts with KLF5 and stabilizes KLF5 by reducing its polyubiquitination and proteasomal degradation. The UCHL1-KLF5 axis collaboratively upregulates EGFR expression while downregulating ESR1 expression at both mRNA and protein levels in TNBC. UCHL1 knockdown slows the proliferation of TNBC cells and sensitizes the tumor cells to Tamoxifen and Fulvestrant. KLF5 overexpression partially reverses these trends. Both TET1 and TET3 can bind to the UCHL1 promoter region, reducing methylation of associated CpG sites and enhancing UCHL1 transcription in TNBC cell lines. Additionally, TET1 and TET3 elevates KLF5 protein level in a UCHL1-dependent manner. Conclusion: UCHL1 plays a pivotal role in TNBC by deubiquitinating and stabilizing KLF5, contributing to endocrine therapy resistance. TET1 and TET3 promote UCHL1 transcription through promoter demethylation and maintain KLF5 protein level in a UCHL1-dependent manner, implying their potential as therapeutic targets in TNBC. [ABSTRACT FROM AUTHOR]

BACKGROUND: Epithelial-mesenchymal transition (EMT) is an important biological process by which malignant tumor cells to acquire migration and invasion abilities. This study explored the role of KLF5 in the EMT process of in cervical cancer cell lines. OBJECTIVE: Krüpple-like factor 5 (KLF5) is a basic transcriptional factor that plays a key role in cell-cycle arrest and inhibition of apoptosis. However, the molecular mechanism by which KLF5 mediates the biological functions of cervical cancer cell lines has not been elucidated. Here, we focus on the potential function of ELF5 in regulating the EMT process in in vitro model of cervical cancer cell lines. METHOD: Western-blot and real-time quantitative PCR were used to detect the expression of EMT-related genes in HeLa cells. MTT assays, cell scratch and Transwell assays were used to assess HeLa cells proliferation and invasion capability. Using the bioinformatics tool JASPAR, we identified a high-scoring KLF5-like binding sequence in the SNAI1 gene promoter. Luciferase reporter assays was used to detect transcriptional activity for different SNAI1 promoter truncates. RESULT: After overexpressing the KLF5 gene in HeLa cells, KLF5 not only significantly inhibited the invasion and migration of HeLa cells, but also increased the expression of E-cadherin and decreased the expression of N-cadherin and MMP9. In addition, the mRNA expression of upstream regulators of E-cadherin, such as SNAI1, SLUG, ZEB1/2 and TWIST1 was also decreased. Furthermore, KLF5 inhibiting the expression of the SNAI1 gene via binding its promoter region, and the EMT of Hela cells was promoted after overexpression of the SNAI1 gene. CONCLUSION: These results indicate that KLF5 can downregulate the EMT process of HeLa cells by decreasing the expression of the SNAI1 gene, thereby inhibiting the migration and invasion of HeLa cervical cancer cells. [ABSTRACT FROM AUTHOR]

Krüppel-like factor (KLF)5, which is overexpressed in carcinomas such as oral cancer, inhibits epidermal differentiation. KLF5 induces dedifferentiation of carcinoma cells, which effectuates carcinoma progression; nevertheless, the regulatory mechanism affecting the transcription of the KLF5 gene remains ambiguous. Transcriptional activity of the KLF5 silencer, specifically the 425-bp region (425-region), was examined using reporter assays. An additional analysis was conducted to assess the impact of the minimal essential region (MER) of KLF5 on its basal expression. The affinity of cAMP responsive element binding protein 1 (CREB1) for three potential CREB1-binding sites in the 425-region was analyzed using DNA pull-down and quantitative chromatin immunoprecipitation assays. Reporter assays employing a human oral squamous carcinoma cell line, HSC2, transfected with small interfering RNA or complementary DNA for CREB1 , were performed to investigate the effect of CREB1 binding sites on MER activity. The 425-region exhibited no transcriptional activity and suppressed MER transcriptional activity. This region encodes three putative CREB1-binding sites, and CREB1 demonstrated equal binding affinity for all three sites. The deletion of each of these binding sites reduced CREB1 precipitation and enhanced MER activity. Endogenous CREB1 knockdown and overexpression elevated and reduced MER activity, respectively, at the intact sites. Conversely, site deletion hampered and improved MER activity upon CREB1 knockdown and overexpression, respectively. Suppression of KLF5 basal expression via CREB1 binding to the 425-region requires all three CREB1-binding sites to remain intact in oral carcinoma cells. Consequently, deletion of the CREB1-binding site relieves suppression of KLF5 basal expression. [ABSTRACT FROM AUTHOR]

The highly expressed oncogenic factor Krüppel‐like factor 5 (KLF5) promotes various cancerous processes, such as cell growth, survival, anti‐apoptosis, migration and metastasis, particularly in lung cancer. Nevertheless, the modifications to KLF5 after translation are poorly understood. Protein arginine methyltransferase 5 (PRMT5) is considered as an oncogene known to be involved in different types of carcinomas, including lung cancer. Here, we show that the expression levels of PRMT5 and KLF5 are highly expressed lung cancer. Moreover, PRMT5 interacts with KLF5 and facilitates the dimethylation of KLF5 at Arginine 41 in a manner that depends on methyltransferase activity. Downregulation or pharmaceutical suppression of PRMT5 reduces the expression of KLF5 and its downstream targets both in vitro and in vivo. Mechanistically, the dimethylation of KLF5 by PRMT5 promotes the maintenance and proliferation of lung cancer cells at least partially by stabilising KLF5 via regulation of the Akt/GSK3β signalling axis. In summary, PRMT5 methylates KLF5 to prevent its degradation, thereby promoting the maintenance and proliferation of lung cancer cells. These results suggest that targeting PRMT5/KLF5 axis may offer a potential therapeutic strategy for lung cancer. [ABSTRACT FROM AUTHOR]

Krüppel-like zinc-finger transcription factor 5 (KLF5) is a vital regulator of breast cancer (BC) onset and progression. The mechanism by which KLF5 regulates BC is still not clearly known. In this study, bioinformatics analysis shows that BC-affected individuals with elevated KLF5 expression levels have poor clinical outcomes. We further verify that miR-145-5p regulated KLF5 expression to promote cell apoptosis and inhibit cell proliferation in BC via dual-luciferase reporter assay, western blot analysis, qRT-PCR, CCK-8 assay and cell apoptosis assay. In addition, based on bioinformatics analysis, the binding of ENST00000422059 with miR-145-5p is confirmed by dual-luciferase reporter assay. Subsequently, FISH, western blot analysis, qRT-PCR, CCK-8 and cell apoptosis assays verified that ENST00000422059 increases KLF5 protein expression by sponging miRNA to promote cell proliferation and inhibit cell apoptosis. Finally, ENST00000422059 is found to accelerate tumor progression by regulating the miR-145-5p/KLF5 axis in vivo. In conclusion, this study suggests that ENST00000422059 upregulates KLF5 by sponging miR-145-5p to promote BC progression.

Krüpple-like factor 5 (KLF5) is a zinc-finger-containing transcription factor implicated in several human malignancies, but its potential regulatory mechanisms implicated in esophageal squamous cell carcinoma (ESCC) remain elusive. Here, we show that KLF5 is upregulated in ESCC, where its level was significantly associated with tumor differentiation and lymph node metastasis status. Upregulated KLF5 expression promoted the proliferation, migration, and invasion of ESCC cells. Reduced KLF5 showed the opposite effects. Mechanistically, KLF5 exerts its tumor promotion effect by up-regulating fibroblast growth factor binding protein 1 (FGF-BP1) and snail family transcriptional repressor 2 (SNAIL2). KLF5 binds to the promoter regions of FGF-BP1 and transcriptionally activates its expression. Our study indicated that KLF5 could promote esophageal squamous cell cancer proliferation, migration, and invasion by upregulating FGF-BP1/SNAIL2 signaling. Our work suggests that KLF5 might be a proto-oncogene in ESCC and implicated in ESCC metastasis. [ABSTRACT FROM AUTHOR]

Early blastomeres of mouse preimplantation embryos exhibit bi-potential cell fate, capable of generating both embryonic and extra-embryonic lineages in blastocysts. Here we identify three major two-cell-stage (2C)-specific endogenous retroviruses (ERVs) as the molecular hallmark of this bi-potential plasticity. Using the long terminal repeats (LTRs) of all three 2C-specific ERVs, we identify Krüppel-like factor 5 (Klf5) as their major upstream regulator. Klf5 is essential for bi-potential cell fate; a single Klf5-overexpressing embryonic stem cell (ESC) generates terminally differentiated embryonic and extra-embryonic lineages in chimeric embryos, and Klf5 directly induces inner cell mass (ICM) and trophectoderm (TE) specification genes. Intriguingly, Klf5 and Klf4 act redundantly during ICM specification, whereas Klf5 deficiency alone impairs TE specification. Klf5 is regulated by multiple 2C-specific transcription factors, particularly Dux, and the Dux/Klf5 axis is evolutionarily conserved. The 2C-specific transcription program converges on Klf5 to establish bi-potential cell fate, enabling a cell state with dual activation of ICM and TE genes.

Acute kidney injury (AKI) progression to chronic kidney disease (CKD) represents a unique renal disease setting characterized by early renal cellular injury and regulated cell death, and later renal fibrosis, of which the critical role and nature of ferroptosis are only partially understood. Here, we report that renal tubular epithelial ferroptosis caused by HDAC3 (histone deacetylase 3) aberration and the resultant GPX4 suppression drives AKI-CKD progression. In mouse models of AKI-CKD transition induced by nephrotoxic aristolochic acid (AA) and folic acid (FA), renal tubular epithelial ferroptosis occurred early that coincided with preferential HDAC3 elevation and marked suppression of a core anti-ferroptosis enzyme GPX4 (glutathione peroxidase 4). Intriguingly, genetic Hdac3 knockout or administration of a HDAC3-selective inhibitor RGFP966 effectively mitigated the GPX4 suppression, ferroptosis and the fibrosis-associated renal functional loss. In cultured tubular epithelial cells, HDAC3 over-expression or inhibition inversely affected GPX4 abundances. Further analysis revealed that Gpx4 promoter contains a typical binding motif of transcription factor KLF5 (Kruppel-like factor 5). HDAC3 and KLF5 inducibly associated and bound to Gpx4 promoter upon AA treatment, leading to local histone hypoacetylation and GPX4 transactivation inhibition, which was blocked by RGFP966 and a KLF5 inhibitor ML264, respectively, suggesting that KLF5 co-regulated the HDAC3-incurred Gpx4 transcription inhibition. More importantly, in AKI-CKD mice receiving a GPX4 inactivator RSL3, the anti-ferroptosis and renoprotective effects of RGFP966 were largely abrogated, indicating that GPX4 is an essential downstream mediator of the HDAC3 aberration and renal ferroptosis during AKI-CKD transition. Together, our study identified a critical epigenetic pathway of ferroptosis during AKI-CKD transition and suggested that the strategies preserving GPX4 by HDAC3 inhibition are potentially effective to reduce renal ferroptosis and slow AKI-CKD progression.

One major characteristic of tumor cells is the aberrant activation of epigenetic regulatory elements, which remodel the tumor transcriptome and ultimately promote cancer progression and drug resistance. However, the oncogenic functions and mechanisms of ovarian cancer (OC) remain elusive. Here, super‐enhancer (SE) regulatory elements that are aberrantly activated in OC are identified and it is found that SEs drive the relative specific expression of the transcription factor KLF5 in OC patients and poly(ADP‐ribose) polymerase inhibitor (PARPi)‐resistant patients. KLF5 expression is associated with poor outcomes in OC patients and can drive tumor progression in vitro and in vivo. Mechanistically, KLF5 forms a transcriptional complex with EHF and ELF3 and binds to the promoter region of RAD51 to enhance its transcription, strengthening the homologous recombination repair (HRR) pathway. Notably, the combination of suberoylanilide hydroxamic acid (SAHA) and olaparib significantly inhibits tumor growth and metastasis of PARPi‐resistant OC cells with high KLF5. In conclusion, it is discovered that SEs‐driven KLF5 is a key regulatory factor in OC progression and PARPi resistance; and potential therapeutic strategies for OC patients with PARPi resistance and high KLF5 are identified. [ABSTRACT FROM AUTHOR]

Glioblastoma (GBM) is the most aggressive and malignant primary tumor. Angiogenesis plays a critical role in the progression of GBM. Previous studies have indicated that long non-coding RNAs (lncRNAs) are abnormally expressed in various cancers and participate in the regulation of the malignant behaviors of tumors. The present study demonstrated that lncRNA antisense 1 to Micro-chromosome maintenance protein 3-associated protein (MCM3AP-AS1) was upregulated whereas miR-211 was downregulated in glioma-associated endothelial cells (GECs). Knockdown of MCM3AP-AS1 suppressed the cell viability, migration, and tube formation of GECs and played a role in inhibiting angiogenesis of GBM in vitro. Furthermore, knockdown of MCM3AP-AS1 increased the expression of miR-211. Luciferase reporter assay implicated that miR-211 targeted KLF5 30-UTR and consequently inhibited KLF5 expression. Besides, in this study we found that MCM3AP-AS1 knockdown decreased KLF5 and AGGF1 expression by upregulating miR-211. In addition, KLF5 was associated with the promoter region of AGGF1. Knockdown of KLF5 decreased AGGF1 expression by transcriptional repression, and also inhibited the activation of PI3K/AKT and ERK1/2 signaling pathways. Overall, this study reveals that MCM3AP-AS1/miR-211/KLF5/AGGF1 axis plays a prominent role in the regulation of GBM angiogenesis and also serves as new therapeutic target for the anti-angiogenic therapy of glioma. [ABSTRACT FROM AUTHOR]

Objective: To explore the role of circROBO1 in promoting the invasion of retinal Y79 cells by targeting KLF5 and its possible regulatory mechanism. Methods: RNase R enzyme digestion and qRT-PCR experiments were used to detect the structural stability of circular circROBO1 in retinal Y79 cells; cytoplasmic and nuclear RNAs of retinal Y79 cells were extracted for localization analysis of circROBO1; The expression of circROBO1 in retinal Y79 cells were silenced by siRNA. The effect of circROBO1 on the migration and invasion ability of HT-29 cells was detected by scratch assay, Transwell cell invasion and migration assay. The target binding sites of circROBO1 and its downstream miRNA and that of miRNA and its downstream target gene KLF5 were predicted by CircInteractome and TargetScan online software respectively, and the target regulation relationship between them was verified by double luciferase reporter gene experiment. Western blot was used to detect the effect of siRNA silencing the expression of circROBO1 in Y79 cells on the expression of KLF5. Results: Compared with the control group without RNase R enzyme treatment, relative circROBO1 levels did not change significantly after treatment, while relative linear ROBO1 levels decreased significantly after treatment (t=16.18, P<0.05); the content of circROBO1 in the cytoplasm was significantly higher than that in the nucleus (P<0.05); compared with sicontrol group, the migration rate and the invasion and migration abilities of Transwell cells were all lower in the si-circROBO1 group (t=22.54, P<0.05); circROBO1 can adsorb miR-885-5p, and there is a target binding site between miR-885-5p and KLF5(t=11.39, P<0.05); compared with the si-control group, the KLF5 protein expression in the si-circROBO1 group was significantly decreased (t=17.26, P<0.05). Conclusions: circROBO1 promotes retinal Y79 cell tumor invasion by targeting KLF5. [ABSTRACT FROM AUTHOR]

Objective: This study aims to elucidate the role of Kruppel‐like factor (KLF5) and myxovirus resistance 1 (MX1) in the progression of renal fibrosis in lupus nephritis (LN). Methods: First, the expression of KLF5 and MX1 was assessed in the peripheral blood of LN patients and healthy participants. Next, the pathological changes in renal tissues were evaluated and compared in BALB/c and MRL/lpr mice, by detecting the expression of fibrosis marker proteins (transforming growth factor‐β [TGF‐β] and CTGF) and α‐SMA, the content of urine protein, and the levels of serum creatinine, blood urea nitrogen, and serum double‐stranded DNA antibody. In TGF‐β1‐induced HK‐2 cells, the messenger RNA levels of KLF5 and MX1 were tested by qRT‐PCR, and the protein expression of α‐SMA, type I collagen (Col I), fibronectin (FN), and matrix metalloproteinase 9 (MMP9) was measured by western blot analysis. Moreover, the relationship between KLF5 and MX1 was predicted and verified. Results: In renal tissues of MRL/lpr mice and the peripheral blood of LN patients, KLF5 and MX1 were highly expressed. Pearson analysis revealed that KLF5 was positively correlated with MX1. Furthermore, KLF5 bound to MX1 promoter and promoted its transcription level. MRL/lpr mice showed substantial renal injury, accompanied by increased expression of α‐SMA, TGF‐β, CTGF, Col I, FN, and MMP9. Injection of sh‐KLF5 or sh‐MX1 alone in MRL/lpr mice reduced renal fibrosis in LN, while simultaneous injection of sh‐KLF5 and ad‐MX1 exacerbated renal injury and fibrosis. Furthermore, we obtained the same results in TGF‐β1‐induced HK‐2 cells. Conclusion: Knockdown of KLF5 alleviated renal fibrosis in LN through repressing the transcription of MX1. [ABSTRACT FROM AUTHOR]

The effective proliferation and differentiation of trophoblast stem cells (TSCs) is indispensable for the development of the placenta, which is the key to maintaining normal fetal growth during pregnancy. Kruppel-like factor 5 (Klf5) is implicated in the activation of pluripotency gene expression in embryonic stem cells (ESCs), yet its function in TSCs is poorly understood. Here, we showed that Klf5 knockdown resulted in the downregulation of core TSC-specific genes, consequently causing rapid differentiation of TSCs. Consistently, Klf5 -depleted embryos lost the ability to establish TSCs in vitro. At the molecular level, Klf5 preferentially occupied the proximal promoter regions and maintained an open chromatin architecture of key TSC-specific genes. Deprivation of Klf5 impaired the enrichment of p300, a major histone acetyl transferase of H3 lysine 27 acetylation (H3K27ac), and further reduced the occupancy of H3K27ac at promoter regions, leading to decreased transcriptional activity of TSC pluripotency genes. Thus, our findings highlight a novel mechanism of Klf5 in regulating the self-renewal and differentiation of TSCs and provide a reference for understanding placental development and improving pregnancy rates. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Melatonin regulates the mammalian circadian rhythm and plays metabolic functions such as glucose homeostasis. Both melatonin receptors (MTNR1A and MTNR1B, encoded by the MTNR1A and MTNR1B genes, respectively) are expressed in pancreatic beta cells and mediate the glucometabolic roles of melatonin as well as insulin secretion. The MTNR1B gene is a well-known genetic risk factor in type 2 diabetes (T2D); however, little is known about the involvement of the MTNR1A gene in here T2D. We aimed to investigate whether MTNR1A is linked to and/or associated with familial T2D. SUBJECTS AND METHODS: We genotyped 14 single nucleotide polymorphisms within the MTNR1A gene in 212 peninsular Italian families with T2D. We performed parametric linkage and linkage disequilibrium analyses to investigate the role of MTNR1A variants in conferring T2D risk. We considered variants statistically significant if conferring linkage or linkage disequilibrium with p < 0.05. RESULTS: We found 3 novel variants (rs62350392, rs2119883, and rs13147179) significantly linked to and/or associated with T2D in multigenerational Italian families. CONCLUSIONS: This is the first study to report MTNR1A as a novel risk gene in T2D. Functional studies are needed to confirm these results. [ABSTRACT FROM AUTHOR]

Despite the development of cancer therapies, the success of most treatments has been impeded by drug resistance. The crucial role of tumor cell plasticity has emerged recently in cancer progression, cancer stemness and eventually drug resistance. Cell plasticity drives tumor cells to reversibly convert their cell identity, analogous to differentiation and dedifferentiation, to adapt to drug treatment. This phenotypical switch is driven by alteration of the transcriptome. Several pluripotent factors from the KLF and SOX families are closely associated with cancer pathogenesis and have been revealed to regulate tumor cell plasticity. In this review, we particularly summarize recent studies about KLF4, KLF5 and SOX factors in cancer development and evolution, focusing on their roles in cancer initiation, invasion, tumor hierarchy and heterogeneity, and lineage plasticity. In addition, we discuss the various regulation of these transcription factors and related cutting-edge drug development approaches that could be used to drug "undruggable" transcription factors, such as PROTAC and PPI targeting, for targeted cancer therapy. Advanced knowledge could pave the way for the development of novel drugs that target transcriptional regulation and could improve the outcome of cancer therapy. [ABSTRACT FROM AUTHOR]

Accumulating evidence suggests that human umbilical cord mesenchymal stem cell‐derived exosomes (hUC‐MSCs‐Exos) are a promising therapeutic strategy for cerebral ischemia–reperfusion injury (CIRI). However, the underlying mechanism remains unclear. hUC‐MSCs‐Exos were identified by electron microscopy, NTA, and Western blotting. In the hypoxia/reoxygenation (H/R) cell model, human brain microvascular endothelial cells (HBMECs) were cocultured with hUC‐MSCs‐Exos. Then, cell viability, migration, apoptosis, and tube formation were measured by MTT, flow cytometry, transwell, and tube formation assays. RT‐qPCR and Western blotting were used to detect the changes in RNA and protein. RNA pull‐down and dual luciferase reporter assays confirmed the relationship between circDLGAP4, miR‐320, and KLF5. Ischemia–reperfusion (I/R) rat model was established for in vivo experiments. hUC‐MSCs‐Exos increased the expression levels of circDLGAP4 and KLF5 but decreased miR‐320 in H/R‐treated HBMECs by transferring exosomal circDLGAP4. Knockdown of circDLGAP4 in hUC‐MSCs‐Exos reversed the promoting effects of hUC‐MSCs‐Exos on cell viability, migration, and tube formation in H/R‐treated HBMECs in vitro and also abolished the protective effects of hUC‐MSCs‐Exos on cerebrovascular injury in I/R rats. Mechanistically, exosomal circDLGAP4 negatively regulated miR‐320 in HBMECs, which directly bound to KLF5. In addition, the downregulation of miR‐320 could reverse the regulatory effect of exosomal shcircDLGAL5 in H/R‐treated HBMECs by upregulating KLF5. hUC‐MSCs‐Exos‐derived circDLGAP4 reduced cerebrovascular injury by regulating miR‐320/KLF5 signaling. These results provide a stem cell‐based approach to treat CIRI. [ABSTRACT FROM AUTHOR]