Early growth response 1/Krüppel-like factor 5 pathway inhibitor alleviates lipopolysaccharide-induced lung injury by promoting autophagy

Early transcription factors play critical roles in the development of acute lung injury/acute respiratory distress syndrome (ALI/ARDS). Early growth response 1 (EGR1) is a transcription factor essential for various biological processes, including regulation of metabolism, differentiation, and inflammation. However, its role in ALI has been poorly reported. In this study, we aimed to determine the effect of EGR1 on ALI to gain insights into the theoretical basis for further treatment of ALI. By employing concerted molecular biology techniques, we showed that EGR1 protein was upregulated in mice. EGR1 protein was upregulated in mice and human lung epithelial cells in response to lipopolysaccharide (LPS) stimulation. EGR1 knockdown promoted autophagy and reduced LPS-induced pro-inflammatory mediator production. EGR1 was preferentially bound to the GCGTGGGCG motif region and EGR1-binding peak-related genes were mainly enriched in autophagy and injury stress-related pathways. Additionally, EGR1 promoted Krüppel-like factor 5 (KLF5) transcription by binding to the KLF5 promoter region, and KLF5 knockdown significantly decreased inflammatory damage, suggesting that EGR1 promotes ALI progression by regulating KLF5 expression. Furthermore, ML264, an inhibitor of the EGR1/KLF5 pathway axis, displayed a protective role in ALI to reduce inflammation. In conclusion, our findings demonstrate the potential of EGR1 knockdown to inhibit KLF5 and promote autophagy, further reducing the inflammatory response to mitigate ALI/ARDS. The EGR1/KLF5 pathway axis may be a valuable therapeutic target for the treatment of ALI/ARDS.

Krüppel-like Factor 5 Plays an Important Role in the Pathogenesis of Chronic Pancreatitis

Chronic pancreatitis results in the formation of pancreatic intraepithelial neoplasia (PanIN) and poses a risk of developing pancreatic cancer. Our previous study demonstrated that Krüppel-like factor 5 (KLF5) is necessary for forming acinar-to-ductal metaplasia (ADM) in acute pancreatitis. Here, we investigated the role of KLF5 in response to chronic injury in the pancreas. Human tissues originating from chronic pancreatitis patients showed increased levels of epithelial KLF5. An inducible genetic model combining the deletion of Klf5 and the activation of KrasG12D mutant expression in pancreatic acinar cells together with chemically induced chronic pancreatitis was used. The chronic injury resulted in increased levels of KLF5 in both control and KrasG12D mutant mice. Furthermore, it led to numerous ADM and PanIN lesions and extensive fibrosis in the KRAS mutant mice. In contrast, pancreata with Klf5 loss (with or without KrasG12D) failed to develop ADM, PanIN, or significant fibrosis. Furthermore, the deletion of Klf5 reduced the expression level of cytokines and fibrotic components such as Il1b, Il6, Tnf, Tgfb1, Timp1, and Mmp9. Notably, using ChIP-PCR, we showed that KLF5 binds directly to the promoters of Il1b, Il6, and Tgfb1 genes. In summary, the inactivation of Klf5 inhibits ADM and PanIN formation and the development of pancreatic fibrosis.

Krüppel-like factor 5 activates chick intestinal stem cell and promotes mucosal repair after impairment

The mucosal renewal, which depends on the intestinal stem cell (ISC) activity, is the foundation of mucosal repairment. Importantly, activation of reserve ISCs (rISCs) plays a vital role in initiating mucosal repair after injury. However, the underlying regulatory mechanism of rISCs activation in chickens remains unclear. In this study, immediately after lipopolysaccharide (LPS) challenge, mitochondrial morphological destruction and dysfunction appeared in the crypt, accompanied by decreased epithelial secretion (decreased Muc2 mRNA abundance and LYSOZYME protein level). However, immediately after mucosal injury, the mucosal renewal accelerated, as indicated by the increased BrdU positive rate, proliferating cell nuclear antigen (PCNA) protein level and mRNA abundance of cell cycle markers (Ccnd1, Cdk2). Concerning the ISCs activity, during the early period of injury, there appeared a reduction of active ISCs (aISCs) marker Lgr5 mRNA and protein, and an increasing of rISCs marker Hopx mRNA and protein. Strikingly, upon LPS challenge, increased mRNA transcriptional level of Krüppel-like factor 5 (Klf5) was detected in the crypt. Moreover, under LPS treatment in organoids, the KLF5 inhibitor (ML264) would decrease the mRNA and protein levels of Stat5a and Hopx, the STAT5A inhibitor (AC-4-130) would suppress the Lgr5 mRNA and protein levels. Furthermore, the Dual-Luciferase Reporter assay confirmed that, KLF5 would bind to Hopx promoter and activate the rISCs, STAT5A would trigger Lgr5 promoter and activate the aISCs. Collectively, KLF5 was upregulated during the early period of injury, further activate the rISCs directly and activate aISCs via STAT5A indirectly, thus initiate mucosal repair after injury.

KLF5‑mediated expression of CARD11 promotes the progression of gastric cancer

Caspase recruitment domain-containing protein 11 (CARD11) has been reported as functioning in multiple types of cancers. In the present study, the role and mechanism of CARD11 in gastric cancer was investigated. First, CARD11 expression in gastric cancer tissues and the association of CARD11 with overall survival were analyzed by the encyclopedia of RNA interactomes database. CARD11 expression in gastric cancer cells was detected by western blotting and reverse transcription-quantitative PCR analyses. After CARD11 silencing, cell proliferation was evaluated by Cell Counting Kit-8 assay, 5-ethynyl-2'-deoxyuridine staining and flow cytometry analysis. Wound healing and Transwell assays were used to measure the capacities of cell migration and invasion. Additionally, the expression levels of epithelial-mesenchymal transition (EMT)-related proteins and mTOR-related proteins were detected by western blot analysis. HumanTFDB predicted the binding of the transcription factor Krüppel-like factor 5 (KLF5) to the CARD11 promoter, which was confirmed by dual luciferase reporter and chromatin immunoprecipitation assays. To explore the regulatory effects between KLF5 and CARD11, KLF5 was overexpressed to perform the rescue experiments in gastric cancer cells with CARD11 silencing. Results revealed that CARD11 was highly expressed in gastric cancer and was associated with poor prognosis. CARD11 interference inhibited the proliferation of gastric cancer cells and induced cell cycle arrest. Additionally, CARD11 silencing suppressed the migration, invasion and EMT of gastric cancer cells, accompanied by upregulated E-cadherin expression and downregulated N-cadherin and vimentin expression. Moreover, the transcription factor KLF5 positively regulated the transcription of CARD11 in gastric cancer. KLF5 overexpression reversed the effects of interference of CARD11 expression in gastric cancer cells to promote their proliferation, migration, invasion and EMT. KLF5 overexpression also led to a reduction in cell cycle arrest. Finally, interference of CARD11 expression suppressed the mTOR pathway, which was activated by KLF5. In conclusion, KLF5-mediated CARD11 promoted the proliferation, migration and invasion of gastric cancer cells.

Blockade of KLF5/LDH-A feedback loop contributes to Curcumol inhibition of sinusoidal endothelial cell glycolysis and mitigation of liver fibrosis

BACKGROUND

LSECs (Liver sinusoidal endothelial cells) are the portal of liver, their pathological angiogenesis plays a constructive role in etiopathogenesis of liver fibrosis by affecting liver tissue repair and inflammatory drive. Although intervention in angiogenesis can effectively inhibit abnormal activation of LSEC, no effective drugs have been found to treat liver fibrosis.

PURPOSE

We investigated the effect of the natural compound Curcumol on LSEC angiogenesis and elucidated the novel underlying mechanism, expecting to provide a scientific basis for exploring potential therapeutic drugs for liver fibrosis.

METHODS

Various cellular and molecular assays, as well as genetic assays, were used to detect pathological angiogenesis and changes in glycolysis levels in cultured rat LSECs and mouse liver fibrosis models.

RESULTS

Transcription factor KLF5 is able to influence the angiogenic properties of LSEC by regulating the glycolytic process, and affect the expression of LDH-A by transcriptionally binding to its promoter. In our study, we were surprised to find that LDH-A (the final step of glycolysis) has a strong regulatory effect on the glycolytic process of LSEC. Through in-depth study, we found that LDH-A could affect the transcriptional activity of KLF5, thus forming a positive feedback loop. Curcumol could break this positive feedback loop and inhibit the glycolysis-dependent angiogenic nature of LSEC, thus alleviating liver fibrosis. Curcumol reduced extracellular matrix (ECM) deposition, attenuated pathological angiogenesis in LSEC, and decreased the level of CCl₄-induced liver fibrosis in mice.

CONCLUSION

Our results demonstrated the great utilization potentiality of KLF5 in liver fibrosis, and the innovative discovery that LDH-A regulates the glycolytic process and forms a malignant feedback loop by exerting non-enzymatic effects. It also reveals the prospect of Curcumol-regulated KLF5/LDH-A feedback loop in the treatment of liver fibrosis, providing a new option for the future medicine of liver fibrosis.

KLF5-mediated CDCA5 expression promotes tumor development and progression of epithelial ovarian carcinoma

Cell division cycle associated 5 (CDCA5) is correlated with the development and progression of many malignant tumors. However, little is known about its role in epithelial ovarian cancer (EOC) progression. In this study, the clinical value, biological function and underlying mechanisms of CDCA5 in EOC were evaluated. CDCA5 mRNA and protein levels were substantially upregulated in EOC and had a significant positive correlation with adverse clinicopathological characteristics and a poor prognosis. CDCA5 facilitated proliferation, invasion, and metastasis and disrupted mitochondrial-mediated endogenous apoptosis by activating the cell cycle pathway and inhibiting the P53 pathway in EOC cells. Conversely, knockdown of CDCA5 expression blocked the malignant activities of EOC cells and suppressed the growth of xenograft tumors in vivo. Mechanistically, the transcription factor KLF5 bound to a specific site in the CDCA5 promoter and promoted CDCA5 expression. Moreover, KLF5 overexpression rescued the negative regulation of inhibited CDCA5 expression on EOC cell proliferation. In conclusion, our findings revealed that CDCA5 promoted tumor progression of EOC via the KLF5/CDCA5/cell cycle and P53 axes, which might provide new insights into the roles of CDCA5 in EOC.

Inhibiting Intestinal Krüppel-Like Factor 5 Impairs the Beneficial Role of Renal Denervation in Gut Microbiota in Rats with Heart Failure

Krüppel-like factor 5 (KLF5) is critical in maintaining intestinal barrier function, and renal denervation (RDN) mitigates gut microbiota aberrations in rats with heart failure (HF). It is unclear whether intestinal KLF5 can be regulated by RDN and whether inhibiting intestinal KLF5 weakens the beneficial role of RDN on gut microbiota. Sprague-Dawley rats were distributed into a CG (sham transverse aortic constriction [TAC] and sham RDN), HF (induced by TAC), or RDN (underwent RDN after TAC) group or a CG.M, HF.M, or RDN.M group, which included the administration of the KLF5 inhibitor to the CG, HF, or RDN group, respectively. Transmission electron microscopy, mRNA, and protein expression of KLF5 and desmoglein 2 (DSG2) in jejunum and sequencing of the 16S rRNA gene in fecal samples were evaluated. KLF5 expression was lower in the RDN group than in the HF group (P < 0.001). The microvillus length, density, length-to-width ratio, and DSG2 expression were lower in the RDN.M group than in the RDN group, and the same trend was observed between the HF.M and HF groups (all P < 0.05). The gut bacterial community structure was altered after administration of a KLF5 inhibitor. The abundances of Proteobacteria, Gammaproteobacteria, Sutterella, and Prevotellaceae were higher, and the abundance of Firmicutes was lower in the RDN.M group than in the RDN group (all P < 0.05). These findings indicated that RDN suppressed intestinal KLF5 expression, and inhibiting intestinal KLF5 expression exacerbated the gut microbiota by impairing the intestinal barrier function in HF rats following RDN, which weakened the beneficial role of RDN on gut microbiota. IMPORTANCE Krüppel-like factor 5 (KLF5) is critical for the maintenance of intestinal barrier function. It is unclear whether intestinal KLF5 expression can be affected by renal denervation (RDN) in heart failure (HF) and whether inhibiting intestinal KLF5 expression exacerbates the gut microbiome and weakens the role of RDN in mitigating gut microbiome aberrations in HF rats after RDN. We demonstrated that RDN significantly suppressed intestinal KLF5 expression and that inhibiting intestinal expression of KLF5 exacerbated the gut microbiota and weakened the role of RDN in mitigating microbiota aberrations by impairing intestinal barrier function, resulting in an increase in bacteria harmful to cardiac function and a decrease in beneficial bacteria in HF rats following RDN. This study highlighted the important roles of intestinal KLF5 in modulating gut microbiota in HF and suggested that the influence of RDN on intestinal KLF5 was another possible role of RDN in HF besides downregulating the sympathetic nerve.

Lysophosphatidic Acid Promotes Epithelial-Mesenchymal Transition in Kidney Epithelial Cells via the LPAR1/MAPK-AKT/KLF5 Signaling Pathway in Diabetic Nephropathy

The epithelial–mesenchymal transition (EMT) is a differentiation process associated with fibrogenesis in diabetic nephropathy (DN). Lysophosphatidic acid (LPA) is a small, naturally occurring glycerophospholipid implicated in the pathogenesis of DN. In this study, we investigated the role of LPA/LPAR1 signaling in the EMT of tubular cells as well as the underlying mechanisms. We observed a decrease in E-cadherin and an increase in vimentin expression levels in the kidney tubules of diabetic db/db mice, and treatment with ki16425 (LPAR1/3 inhibitor) inhibited the expression of these EMT markers. Ki16425 treatment also decreased the expression levels of the fibrotic factors fibronectin and alpha-smooth muscle actin (α-SMA) in db/db mice. Similarly, we found that LPA decreased E-cadherin expression and increased vimentin expression in HK-2 cells, which was reversed by treatment with ki16425 or AM095 (LPAR1 inhibitor). In addition, the expression levels of fibronectin and α-SMA were increased by LPA, and this effect was reversed by treatment with ki16425 and AM095 or by LPAR1 knockdown. Moreover, LPA induced the expression of the transcription factor, Krüppel-like factor 5 (KLF5), which was decreased by AM095 treatment or LPAR1 knockdown. The expression levels of EMT markers and fibrotic factors induced by LPA were decreased upon KLF5 knockdown in HK-2 cells. Inhibition of the extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and serine-threonine kinase (AKT) pathways decreased LPA-induced expression of KLF5 and EMT markers. In conclusion, these data suggest that LPA contributes to the pathogenesis of diabetic nephropathy by inducing EMT and renal tubular fibrosis via regulation of KLF5 through the LPAR1.

Subversive molecular role of Krüppel-like factor 5 in extracellular matrix degradation and chondrocyte dedifferentiation

Osteoarthritis (OA) is the most common joint disorder worldwide and a leading cause of pain and disability. However, the pathogenesis of osteoarthritis has not been elucidated. Krüppel-like factor (KLF)-5 is involved in several biological processes, including inflammation and cell differentiation, but its role in OA has not been evaluated. In this study, we investigated the role of KLF-5 in chondrocyte differentiation. KLF-5 overexpression in chondrocytes induced a loss of type II collagen expression and sulfated proteoglycan synthesis at the transcriptional and translational levels. Based on immunofluorescence staining, the ectopic expression of KLF-5 reduced type II collagen expression. In contrast, with KLF-5-transfected cells, KLF-5 siRNA transfection-induced type II expression also blocked dedifferentiation caused by the overexpression of KLF-5. In zebra fish, KLF-5 reduced the sulfated proteoglycan synthesis of ceratobranchial cartilage. Our results suggest that KLF-5 plays a pivotal role in the dedifferentiation of rabbit articular cartilage and zebra fish, providing a basis for therapeutic strategy for osteoarthritis aimed at controlling cartilage destruction.

Nanoparticle-Delivered microRNA-153-3p Alleviates Myocardial Infarction-Induced Myocardial Injury in a Rat Model

Although microRNA-153-3p (miR-153-3p) has been demonstrated to confer protective roles in ischemia/reperfusion injury, its potential role in myocardial infarction (MI) remains undefined. Small-molecule modifiers and nanoparticles loaded with microRNAs (miRNAs) have emerged as potential therapeutic reagents for MI treatment. In this study, we prepared liposome nanoparticles, hyaluronic acid (HA)-cationic liposomes (CLPs) complex, for the delivery of miR-153-3p and delineated the mechanistic actions of miR-153-3p modified by nHA-CLPs in MI-induced injury. Our data suggested that nHA-CLPs-loaded miR-153-3p protected cardiomyocytes against MI-induced cardiomyocyte apoptosis and myocardial injury. miR-153-3p was bioinformatically predicted and experimentally verified to bind to Krüppel-like factor 5 (KLF5) 3'UTR and negatively regulate its expression. Hypoxia was adopted to stimulate MI-induced injury to cardiomyocytes in vitro, in which miR-153-3p presented anti-apoptotic potential. However, restoration of KLF5 reversed this anti-apoptotic effect of miR-153-3p. Furthermore, KLF5 was demonstrated to be an activator of the NF-κB pathway. KLF5 enhanced cardiomyocyte apoptosis and inflammation under hypoxic conditions through NF-κB pathway activation, while nHA-CLPs-loaded miR-153-3p suppressed inflammation by blocking the NF-κB pathway. Collectively, our findings suggested the cardioprotective role of miR-153-3p against MI and the successful delivery of miR-153-3p by nHA-CLPs. The identification of KLF5-mediated activation of NF-κB pathway as an apoptotic and inflammatory mechanism aids in better understanding of the biology of MI and development of novel therapeutic strategies for MI.

Krüppel-like factor (KLF)5: An emerging foe of cardiovascular health

Krüppel-like factors (KLFs) are DNA-binding transcriptional factors, which regulate various pathways that pertain to development, metabolism and other cellular mechanisms. KLF5 was first cloned in 1993 and by 1999, it was reported as the intestinal-enriched KLF. Beyond findings that have associated KLF5 with normal development and cancer, it has been associated with various types of cardiovascular (CV) complications and regulation of metabolic pathways in the liver, heart, adipose tissue and skeletal muscle. Specifically, increased KLF5 expression has been linked with cardiomyopathy in diabetes, end-stage heart failure, and as well as in vascular atherosclerotic lesions. In this review article, we summarize research findings about transcriptional, post-transcriptional and post-translational regulation of KLF5, as well as the role of KLF5 in the biology of cells and organs that affect cardiovascular health either directly or indirectly. Finally, we propose KLF5 inhibition as an emerging approach for cardiovascular therapeutics.

Histamine Deficiency Promotes Myofibroblasts Transformation from HDC-Expressing CD11b+ Myeloid Cells in Injured Hearts Post Myocardial Infarction

Myocardial infarction (MI) is a significant contributor to the development of heart failure. Histidine decarboxylase (HDC), the unique enzyme that converts L-histidine to histamine, is highly expressed in CD11b⁺ immature myeloid cells. However, the relationship between HDC-expressing macrophages and cardiac myofibroblasts remains to be explained. Here, we demonstrate that the GFP (green fluorescent protein)-labeled HDC⁺CD11b⁺ myeloid precursors and their descendants could differentiate into fibroblast-like cells in myocardial interstitium. Furthermore, we prove that CD11b⁺Ly6C⁺ monocytes/macrophages, but not CD11b⁺Ly6G⁺ granulocytes, are identified as the main cellular source for bone marrow-derived myofibroblast transformation, which could be regulated via histamine H1 and H2 receptor-dependent signaling pathways. Using HDC knockout mice, we find that histamine deficiency promotes myofibroblast transformation from Ly6C⁺ macrophages and cardiac fibrosis partly through upregulating the expression of Krüppel-like factor 5 (KLF5). Taken together, our data uncover a central role of HDC in regulating bone marrow-derived macrophage-to-myofibroblast transformation but also identify a histamine receptor (HR)-KLF5 related signaling pathway that mediates myocardial fibrosis post-MI. CD11b⁺Ly6C⁺ monocytes/macrophages are the main cellular source for bone marrow-derived myofibroblast transformation. Histamine inhibits myofibroblasts transformation via H1R and H2R-dependent signaling pathways, and ameliorates cardiac fibrosis partly through upregulating KLF5 expression.

MicroRNA-146a-3p/HDAC1/KLF5/IKBα signal axis modulates plaque formation of atherosclerosis mice

BACKGROUND

Atherosclerosis (AS) is a multifocal, smoldering immune inflammatory disease of medium and large arteries driven by lipids. The aim of this study is to discuss the mechanism of microRNA-146a-3p (miR-146a-3p)/histone deacetylase 1 (HDAC1)/Krüppel-like factor 5 (KLF5)/inhibitors of kappa B α (IKBα) signal axis in plaque formation of AS mice.

METHODS

ApoE-/- mice were fed with high-fat feed for 12 weeks to establish AS mice model. The expression of miR-146a-3p, KLF5, HDAC1 and IKBα in aortic wall tissues of AS mice was tested. The targeting relationship between miR-146a-3p and HDAC1 was verified. AS mice were injected with miR-146a-3p antagomir or HDAC1 overexpression to verify the impacts of miR-146a-3p and HDAC1 on blood lipids and inflammatory factors in serum, aortic wall apoptotic cells, antioxidant stress capacity and the plaque area in AS mice. VECs proliferation and apoptosis were also measured in vitro.

RESULTS

miR-146a-3p and KLF5 were increased while HDAC1 and IKBα were reduced in aortic wall tissues of AS mice. miR-146a-3p directly targeted to HDAC1. Depletion of miR-146a-3p or restoration of HDAC1 was correlated to lower plasma lipid level, reduced inflammatory factors in serum, attenuated aortic wall apoptosis, increased antioxidant stress capacity and improved the stability of pathological plaque of AS mice. miR-146a-3p down-regulation or HDAC1 up-regulation promoted VECs proliferation and inhibited apoptosis.

CONCLUSION

Functional studies show that depleted miR-146a-3p advances HDAC1 and IKBα expression as well as inhibits KLF5 expression to facilitate the stability of pathological plaques in AS mice.

[Value of abnormal expression of Krüppel-like zinc-finger protein transcription factor 5 in the diagnosis and prognosis of liver cancer]

Objective: To explore the value of Krüppel-like factor 5 (KLF5), a family member of the zinc finger protein transcription factor, in the diagnosis and prognostic evaluation of hepatocellular carcinoma (HCC). Methods: Cancerous and non-cancerous tissues were collected from 126 cases after HCC surgery by self-matching method with microarray fabrication. Immunohistochemistry was used to analyze the expression of KLF5, clinicopathological characteristics and prognostic value. The sera of 222 cases with chronic liver disease were collected and their KLF5 levels were quantitatively determined by enzyme-linked immunosorbent assay (ELISA). Simultaneously, 40 normal human sera were used as controls to evaluate the value of abnormal KLF5 in the diagnosis and differentiation of benign and malignant liver diseases. T-test, Z-test and χ (2) test were performed on the data. Results: The positive expression rate of KLF5 in the HCC group was 95.2% (120/126), which was significantly higher than the non-cancerous group 38.9% (49/126; χ (2) = 14.385, P < 0.001). KLF5 expression was significantly correlated with TNM stage (stage I 35%, stage II 40%, stage III 74.4%, stage IV 78.1%), tumor size, alpha fetoprotein (AFP) concentration, portal vein embolism, HBV infection and 5-year survival rate. Univariate/multivariate analysis showed that KLF5 high expression was an independent predictor of HCC prognosis. The serum KLF5 level was significantly higher in HCC patients than liver cirrhosis, chronic hepatitis and normal control group (P < 0.001). With the serum KLF5 > 800 ng/ml and AFP > 25 μg/L as limit, the positive rates for HCC diagnosis were 90.48% and 73.81%, respectively, which were lower than the AFP specificity and false positive rate, and was helpful for the differential diagnosis of benign and malignant liver diseases. Conclusion: The overexpression of KLF5 in liver cancer tissues and blood is closely related to the HCC clinical stage and prognosis. Moreover, KLF5 analysis is helpful for HCC diagnosis and differential diagnosis.

Krüppel-like factor 5 is upregulated and induces cell proliferation in endometrial cancer

Krüppel-like factor 5 (KLF5) is involved in various cellular processes, such as cell proliferation and survival. KLF5 has been implicated in cancer pathology. The aim of the present study was to investigate the expression levels and function of KLF5 in endometrial cancer. A total of 30 patients, including 12 patients with endometrial cancer and 18 with benign gynecological diseases (controls), were enrolled at Tokyo Medical University (Tokyo, Japan) between March 2017 and May 2018. Endometrial cancer and control endometrium tissues were collected, and the expression levels of KLF5 were determined using reverse transcription-quantitative PCR, western blotting and immunohistochemistry. For the functional analyses of KLF5 in endometrial cancer, the present study employed a loss-of-function strategy in the human endometrial cancer cell lines in vitro. Ishikawa and HEC1 cells were transduced with lentiviral constructs expressing shRNAs targeting KLF5. MTT and TUNEL assays were performed in cells after knockdown to analyze the role of KLF5 in cell proliferation and survival. The results revealed that the mRNA and protein expression levels of KLF5 were increased in endometrial cancer tissues. In vitro analyses demonstrated that depletion of KLF5 inhibited cell proliferation and decreased the expression levels of cyclin E1. However, silencing KLF5 did not induce cell death. Overall, these results indicated that KLF5 may be crucial in the tumorigenesis of endometrial cancer and has potential as a therapeutic target.

Roles of Krüppel-like factor 5 in kidney disease

Transcription factor Krüppel-like factor 5 (KLF5) is a member of the Krüppel-like factors' (KLFs) family. KLF5 regulates a number of cellular functions, such as apoptosis, proliferation and differentiation. Therefore, KLF5 can play a role in many diseases, including, cancer, cardiovascular disease and gastrointestinal disorders. An important role for KLF5 in the kidney was recently reported, such that KLF5 regulated podocyte apoptosis, renal cell proliferation, tubulointerstitial inflammation and renal fibrosis. In this review, we have summarized the available information in the literature with a brief description on how transcriptional, post-transcriptional and post-translational modifications of KLF5 modulate its function in a variety of organs including the kidney with a focus of its importance on the pathogenesis of various kidney diseases. Furthermore, we also have outlined the current and possible mechanisms of KLF5 activation in kidney diseases. These studies suggest a need for more systemic investigations, particularly for generation of animal models with renal cell-specific deletion or overexpression of KLF5 gene to examine direct contributions of KLF5 to various kidney diseases. This will promote further experimentation in the development of therapies to prevent or treat various kidney diseases.

Silenced long non-coding RNA activated by DNA damage elevates microRNA-495-3p to suppress atherosclerotic plaque formation via reducing Krüppel-like factor 5

OBJECTIVE

Atherosclerosis (AS) is an inflammatory disease and the formation of atherosclerotic plaque plays a critical role in AS progression. We aimed to investigate the effect of long non-coding RNA (lncRNA) activated by DNA damage (NORAD)/microRNA-495-3p (miR-495-3p)/Krüppel-like factor 5 (KLF5) axis on atherosclerotic plaque formation.

METHODS

The ApoE^-/- mice were fed a high-fat diet to construct AS mouse models and the modeled mice were treated with altered NORAD, miR-495-3p or KLF5. NORAD, miR-495-3p and KLF5 expression in mouse aorta tissues were evaluated, and the levels of inflammatory factors, oxidative stress factors, endothelial function indices and blood lipid in mice were all determined. The atherosclerotic plaque area, lipid deposition area, collagen fibers and CD68 expression in mouse aorta tissues were assessed. The regulatory relation between NORAD and miR-495-3p, and the target relation between miR-495-3p and KLF5 were confirmed.

RESULTS

NORAD and KLF5 were increased whereas miR-495-3p was decreased in atherosclerotic mouse aortas. Inhibited NORAD or elevated miR-495-3p suppressed inflammation, oxidative stress, endothelial dysfunction, blood lipid level, atherosclerotic plaque area, collagen fibers and CD68 expression in atherosclerotic mouse aortas. Effects of elevated miR-495-3p on atherosclerotic mice could be reversed by up-regulation of KLF5. NORAD served as a sponge of miR-495-3p and miR-495-3p directly targeted KLF5.

CONCLUSION

Silenced NORAD elevated miR-495-3p to suppress atherosclerotic plaque formation via reducing KLF5. Findings in our research may be helpful for exploring molecular mechanisms of AS.

LncRNA MALAT1/microRNA let-7f/KLF5 axis regulates podocyte injury in diabetic nephropathy

OBJECTIVE

The abnormal expression of microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) has been demonstrated to exert pivotal effects in human diseases. We focused on the functions of metastasis associated lung adenocarcinoma transcript 1 (MALAT1) and microRNA let-7f on diabetic nephropathy (DN).

METHODS

The diabetes (db/db) mice were treated with silenced MALAT1, then the baseline indicators, pathology changes, marker proteins of podocyte injury (nephrin, podocin, desmin and Cleaved caspase-3), oxidative stress indicators and inflammatory factors in renal tissues were determined. Murine podocyte MPC5 cells were stimulated by high glucose (HG) and transfected with sh-MALAT1 or let-7f mimic, then the cell migration, adhesion ability and apoptosis were evaluated. Moreover, the binding relationship between MALAT1 and let-7f, and the targeting relationship between let-7f and krüppel-like factor 5 (KLF5) were confirmed.

RESULTS

Silenced MALAT1 could improve baseline indicators of DN mice, and also improved pathology, increased nephrin and podocin expression, decreased desmin and Cleaved caspase-3 expression, and restrained oxidative stress and inflammatory reaction in their renal tissues. Additionally, elevated let-7f and reduced MALAT1 could restrict migration and apoptosis of HG-induced MPC5 cells, and promoted the cell adhesion ability.

CONCLUSION

Results in our research indicated that the reduced MALAT1 could relieve the podocyte injury in DN by upregulating let-7f and inhibiting KLF5, which may be helpful for DN therapy.

All-Trans Retinoic Acid Prevented Vein Grafts Stenosis by Inhibiting Rb-E2F Mediated Cell Cycle Progression and KLF5-RARα Interaction in Human Vein Smooth Muscle Cells

PURPOSE

Vein graft failure (VGF) is an important limitation for coronary artery bypass graft (CABG) surgery. Inhibition of the excessive proliferation and migration of venous smooth muscle cells (SMCs) is an effective strategy to alleviate VGF during the CABG perioperative period. In the present study, we aimed to explore the role and potential mechanism of all-trans retinoic acid (ATRA) on preventing vein grafts stenosis.

METHODS

The autogenous vein grafts model was established in the right jugular artery of rabbits. Immunohistochemistry staining and western blot assays were used to detected the protein expression, while real-time PCR assay was applied for mRNAs expression detection. The interaction between proteins was identified by co-immunoprecipitation assay. The Cell Counting Kit-8 and wound-healing assays were used to investigate the role of ATRA on human umbilical vein smooth muscle cells (HUVSMCs) function. Cell cycle progression was identified by flow cytometry assay.

RESULTS

Vein graft stenosis and SMCs hyperproliferation were confirmed in vein grafts by histological and Ki-67 immunohistochemistry assays. Treatment of ATRA (10 mg/kg/day) significantly mitigated the stenosis extent of vein grafts, demonstrated by the decreased thickness of intima-media, and decreased Ki-67 expression. ATRA could repress the PDGF-bb-induced excessive proliferation and migration of HUVSMCs, which was mediated by Rb-E2F dependent cell cycle inhibition. Meanwhile, ATRA could reduce the interaction between KLF5 and RARα, thereby inhibiting the function of cis-elements of KLF5. KLF5-induced inducible nitric oxide synthase (iNOS) expression activation could be significantly inhibited by ATRA.

CONCLUSIONS

These results suggested that ATRA treatment may represent an effective prevention and therapy avenue for VGF.

High expression of Krüppel-like factor 5 is associated with poor prognosis in patients with colorectal cancer

Krüppel‐like factor 5 (KLF5) plays an oncogenic role and has diverse functions in cancer cells. However, correlation between KLF5 and clinical outcome has not been determined in patients with colorectal cancer and colorectal liver metastasis. Herein, we analyzed 65 patients with colorectal cancer who developed colorectal liver metastasis. Clinical effects were assessed through immunohistochemical analysis of primary colorectal cancer lesions and metastatic liver lesions. High expression of KLF5 in these tissues correlated with the presence of vascular invasion, elevated serum carbohydrate antigen 19‐9 levels, large diameters of metastatic liver tumors, and poor prognosis following surgery. Multivariate analyses revealed that high expression of KLF5 was an independent prognostic factor. Increased expression of KLF5 in both colorectal cancer primaries and colorectal liver metastasis was significantly associated with shorter overall survival time and time to surgical failure. Krüppel‐like factor 5 expression positively correlated with Ki‐67 and c‐Myc expression in colorectal cancer tissues. In vitro experiments with colon cancer cell lines showed that siRNA knockdown of KLF5 inhibited cell proliferation. Western blot analyses revealed that knockdown of KLF5 expression reduced cyclin D1 and c‐Myc expression. It also impaired the stem cell‐like properties of cancer cells in tumorsphere formation assays. Furthermore, anoikis assay indicated that KLF5 contributed to anoikis resistance. High KLF5 expression is associated with poor prognosis in patients with colorectal cancer and liver metastasis by promoting cell proliferation and cancer stem cell‐like properties.

ML264 inhibits osteosarcoma growth and metastasis via inhibition of JAK2/STAT3 and WNT/β-catenin signalling pathways

Osteosarcoma, the most common bone malignancy, has a high morbidity rate and poor prognosis. Krüppel‐like factor 5 (KLF5) is a key transcriptional regulator of cellular proliferation whose overexpression is observed in osteosarcoma cell lines (U2OS, 143B, MG63 and SAOS2). ML264, a small‐molecule inhibitor of KLF5, exerts antiproliferative effects in colorectal cancer; however, its function in osteosarcoma remains unknown. Here, we explored the possible antitumour effects of ML264 on 143B and U2OS cell lines and murine tumour xenograft model. ML264 suppressed proliferation and clonogenic ability of osteosarcoma cells in a dose‐dependent manner. Moreover, ML264 induced G0/G1 cell cycle arrest, with no influence on apoptosis, and inhibited the migratory and invasive abilities of osteosarcoma cells, as demonstrated by wound‐healing and Transwell assays. Exposure to ML264 reduced the mRNA and protein levels of molecules associated with epithelial‐mesenchymal transition phenotype, including N‐cadherin, vimentin, Snail, matrix metalloproteinase (MMP) 9 and MMP13. Inhibition of signal transducer and activator of transcription (STAT) 3 phosphorylation and Wnt signalling was also observed. In the murine model of osteosarcoma, tumour growth was efficiently suppressed following a 10‐day treatment with ML264. Collectively, our findings demonstrate the potential value of ML264 as a novel anticancer drug for osteosarcoma.

The profibrotic effects of MK-8617 on tubulointerstitial fibrosis mediated by the KLF5 regulating pathway

The discovery of hypoxia-inducible factor (HIF)-prolyl hydroxylase inhibitor (PHI) has revolutionized the treatment strategy for renal anemia. However, the presence of multiple transcription targets of HIF raises safety concerns regarding HIF-PHI. Here, we explored the dose-dependent effect of MK-8617 (MK), a kind of HIF-PHI, on renal fibrosis. MK was administered by oral gavage to mice for 12 wk at doses of 1.5, 5, and 12.5 mg/kg. In vitro, the human proximal tubule epithelial cell line HK-2 was treated with increasing doses of MK administration. Transcriptome profiling was performed, and fibrogenesis was evaluated. The dose-dependent biphasic effects of MK on tubulointerstitial fibrosis (TIF) were observed in chronic kidney disease mice. Accordingly, high-dose MK treatment could significantly enhance TIF. Using RNA-sequencing, combined with in vivo and in vitro experiments, we found that Krüppel-like factor 5 (KLF5) expression level was significantly increased in the proximal tubular cells, which could be transcriptionally regulated by HIF-1α with high-dose MK treatment but not low-dose MK. Furthermore, our study clarified that HIF-1α-KLF5-TGF-β1 signaling activation is the potential mechanism of high-dose MK-induced TIF, as knockdown of KLF5 reduced TIF in vivo. Collectively, our study demonstrates that high-dose MK treatment initiates TIF by activating HIF-1α-KLF5-TGF-β1 signaling. These findings provide novel insights into TIF induction by high-dose MK (HIF-PHI), suggesting that the safety dosage window needs to be emphasized in future clinical applications.-Li, Z.-L., Lv, L.-L., Wang, B., Tang, T.-T., Feng, Y., Cao, J.-Y., Jiang, L.-Q., Sun, Y.-B., Liu, H., Zhang, X.-L., Ma, K.-L., Tang, R.-N., Liu, B.-C. The profibrotic effects of MK-8617 on tubulointerstitial fibrosis mediated by the KLF5 regulating pathway.

MicroRNA-21 promotes proliferation in acute myeloid leukemia by targeting Krüppel-like factor 5

Abnormal expression of microRNA (miR)-21 has been reported in various types of cancers. However, the role and mechanism of miR-21 remain to be elucidated in acute myeloid leukemia (AML). In the present study, it was observed that miR-21 was upregulated and Krüppel-like factor 5 (KLF5) was downregulated in AML cells compared with normal bone marrow cells. Dual luciferase reporter assays revealed that KLF5 was a direct target of miR-21. Indeed, miR-21 overexpression resulted in a downregulation of KLF5 expression, while miR-21 inhibition had the opposite effect in AML cells. In addition, miR-21 overexpression promoted the proliferation of AML cells in vitro. Notably, using a mouse xenograft model, miR-21 overexpression was demonstrated to result in enhanced tumor growth and suppressed KLF5 expression in the xenograft tumors in vivo. In conclusion, the present results indicated that miR-21 promoted proliferation through directly regulating KLF5 expression in AML cells. miR-21 may thus serve as an oncogene in AML, providing a potential target for AML therapy.

Knockdown of KLF5 promotes cisplatin-induced cell apoptosis via regulating DNA damage checkpoint proteins in non-small cell lung cancer

BACKGROUND

Previous research has revealed that Krüppel-like factor 5 (KLF5) may affect DNA damage repair pathways; however, the associated molecular mechanisms are unclear.

METHODS

The expression of KLF5 was studied by immunohistochemical staining in paired tumour and normal tissues from 90 patients with ESCC. We studied the effects of KLF5 knockdown on cell proliferation and apoptosis with or without cisplatin treatment in A549 and H1299 cell lines. Moreover, we examined the effect of KLF5 on the DNA damage response.

RESULTS

KLF5 was significantly overexpressed in non-small cell lung cancer (NSCLC) tissues, and high KLF5 expression predicted poor prognosis for NSCLC patients. The inhibition of KLF5 markedly augmented cisplatin-induced cell apoptosis. In addition, we observed that KLF5 knockdown could decrease DNA repair potential by inhibiting H2AX S139 phosphorylation in response to cisplatin. Moreover, silencing of KLF5 in NSCLC cell lines inhibited the phosphorylation of checkpoint kinases Chk1 S345 and Chk2 T68. KLF5 knockdown permits cells with broken or damaged DNA strands to enter mitosis by inhibiting the activation of H2AX, Chk1 and Chk2, resulting in mitotic catastrophe.

CONCLUSION

KLF5 plays a significant role in the DNA damage response by regulating DNA damage checkpoint proteins. Inhibition of KLF5 may be a potential therapeutic target for NSCLC patients with cisplatin resistance.

The transcription factor Krüppel-like factor 5 promotes cell growth and metastasis via activating PI3K/AKT/Snail signaling in hepatocellular carcinoma

The transcription factor Krüppel-like factor 5 (KLF5) is highly expressed in many cancers and serves as a prognostic factor. However, the function of KLF5 in hepatocellular carcinoma (HCC) is unclear. In this study, we found that KLF5 was significantly overexpressed in HCC cell lines and specimens, and high KLF5 expression predicted a poor prognosis for HCC patients. Then, we studied the effects of KLF5 on the proliferation, apoptosis, migration and invasion of HCC cells in vitro and vivo. The inhibition of KLF5 markedly inhibited HCC growth and metastasis, while KLF5 overexpression promoted these processes. In addition, we observed that KLF5 could promote the epithelial-mesenchymal transition (EMT) in HCC via the PI3K/AKT/Snail signaling pathway. The silencing of KLF5 in HCC cell lines downregulated the expression of N-cadherin, Vimentin and Snail and increased the expression of the epithelial marker E-cadherin. The expression of MMP2 and MMP9 was also decreased in KLF5-silenced HCC cells. However, opposite results were observed in the KLF5-overexpressing group. These results indicate that KLF5 plays a significant role in HCC progression and metastasis and induces EMT via activating PI3K/AKT/Snail signaling, and the inhibition of KLF5 may be a potential treatment modality for patients with HCC.

CINP is a novel cofactor of KLF5 required for its role in the promotion of cell proliferation, survival and tumor growth

Krüppel-like factor 5 (KLF5) both suppresses and promotes tumor growth depending on cellular context. The mechanisms underlying tumor promotion could be targetable for therapy. Although a number of transcriptional targets of KLF5 have been identified and implicated in KLF5-mediated tumor growth, how KLF5 regulates these genes remains to be addressed. Here we performed coimmunoprecipitation (co-IP) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) in the TSU-Pr1 bladder cancer cell line, in which KLF5 is shown to promote tumor growth, to identify KLF5-interacting nuclear proteins that are necessary for KLF5's tumor promoting function. LC-MS/MS revealed 122 potential KLF5 binding proteins in the nuclear proteins precipitated by the KLF5 antibody, and the top nine candidates included AHNAK, TFAM, HSDL2, HNRNPC, CINP, IST1, FBL, PABPC1 and SNRNP40. SRB assays of these nine proteins indicated that silencing CINP had the most potent inhibitory effect on cell growth in KLF5-expressing cells but did not affect parental TSU-Pr1 cells. Further analyses not only confirmed the physical interaction between KLF5 and CINP, also demonstrated that knockdown of CINP attenuated the effects of KLF5 on cell cycle progression, apoptosis and tumorigenesis. Silencing CINP also attenuated the effect of KLF5 on the expression of a number of genes and signaling pathways, including cell cycle regulator Cyclin D1 and apoptosis-related Caspase 7. These results suggest that CINP is a cofactor of KLF5 that is crucial for the promotion of tumor growth, and that the KLF5-CINP interaction could be a novel therapeutic target for inhibiting KLF5-promoted tumor growth.

Elevated Krüppel-like factor 5 expression in spatiotemporal mouse lungs is similar to human congenital cystic adenomatoid malformation of the lungs

Objective

The study aimed to investigate the role of high Krüppel-like factor 5 (KLF5) expression on the pathogenesis of congenital cystic adenomatoid malformation of the lungs (CCAML) in mice.

Methods

A mouse model of high KLF5 expression in the lungs was established. KLF5 expression and the pulmonary lumen diameter were examined by immunohistochemistry to determine a successful model. Basement membrane damage and activity of matrix metalloproteinase-9 (MMP-9) were examined. After an adenovirus carrying KLF5 gene transfection in lung adenocarcinoma (H441) was created, changes in expression and activity of MMP-9 were determined.

Results

In a mouse model with high KLF5 expression, the pulmonary lumen was markedly enlarged, indicating establishment of CCAML. The basement membrane was degraded, and MMP-9 activity was significantly higher in the model group compared with the control group. Moreover, mice in a cellular model after transfection also showed higher MMP-9 activity than did controls.

Conclusion

High KLF5 expression may play a pivotal role in the pathogenesis of CCAML, partly through regulating the activity of MMP-9.

Krüppel-Like Factor 5 Promotes Epithelial Proliferation and DNA Damage Repair in the Intestine of Irradiated Mice

BACKGROUND & AIMS: High doses of radiation induce severe DNA damage in intestinal epithelial cells, especially crypt cells, and cause intestinal injury, but the underlying molecular mechanisms remain unclear. Krüppel-like factor 5 (KLF5), a zinc finger-containing transcription factor, is induced by various stress stimuli and is involved in cell proliferation and survival. The role of KLF5 in radiation-induced intestinal injury was investigated here.

METHODS: Wild type mice were treated with 8 or 15 Gy total body irradiation (TBI). KLF5 content and cellular localization in the small intestines of irradiated mice were detected by Western blot and immunohistochemical analysis. Mice with intestinal-specific knockdown of KLF5 (Vil-Cre; Klf5^fl/+ mice) were generated and their response to radiation was compared with controls. Morphological changes were determined by hematoxylin and eosin staining. Proliferation was examined by Ki67 immunostaining. The molecular response of the small intestine after KLF5 knockdown was investigated using microarrays.

RESULTS: KLF5 expression correlated with the progression of intestinal damage. Decreased levels of KLF5 in the gut were associated with increased damage to the intestinal mucosa and reduced epithelial proliferation after TBI. Our microarray data disclosed that KLF5 knockdown down-regulated genes related to DNA damage repair pathways such as nucleotide excision repair, mismatch repair, non-homologous end joining and the Fanconi anemia pathway, which may suggest a novel function of KLF5.

CONCLUSIONS: Our study illustrates that KLF5 may modulate DNA repair pathways to prevent intestinal injury induced by TBI. KLF5 signaling provides a novel field for identification of potential therapeutic targets for the treatment of radiation-induced intestinal damage.

Unfractionated heparin suppresses lipopolysaccharide-induced monocyte chemoattractant protein-1 expression in human microvascular endothelial cells by blocking Krüppel-like factor 5 and nuclear factor-κB pathway

Unfractionated heparin (UFH) and low-molecular-weight heparins (LMWH), apart from anticoagulant activities, contain a variety of biological properties such as anti-inflammatory actions possibly affecting sepsis. Chemokines are vital for promoting the movement of circulating leukocytes to the site of infection and are involved in the pathogenesis of sepsis. The purpose of this study was to investigate the effects and potential mechanisms of UFH on lipopolysaccharide (LPS)-induced chemokine production in human pulmonary microvascular endothelial cells (HPMECs). HPMECs were pretreated with UFH (0.1 U/ml and 1 U/ml), 15 min prior to stimulation with LPS (10 μg/ml). Cells were cultured under various experimental conditions for 2 h and 6 h for analysis. UFH markedly decreased LPS-induced interleukin (IL)-8 and monocyte chemoattractant protein-1 (MCP-1) mRNA and protein expression in HPMECs. UFH also attenuated the secretion of these chemokines in culture supernatants. In addition, UFH blocked the chemotactic activities of LPS-stimulated HPMECs supernatants on monocytes migration as expected. UFH inhibited LPS-induced Krüppel-like factor 5 (KLF-5) mRNA and protein levels. Concurrently, UFH reduced nuclear factor (NF)-κB nuclear translocation. Importantly, transfection with siRNA targeting KLF-5 reduced NF-κB activation and chemokines expression. These results demonstrate that interfering with KLF-5 mediated NF-κB activation might contribute to the inhibitory effects of chemokines and monocytes migration by UFH in LPS-stimulated HPMECs.

Eradication of gastric cancer is now both possible and practical

In 1994, Helicobacter pylori was declared a human carcinogen. Evidence has now accumulated to show that at least 95% of gastric cancers are etiologically related to H. pylori. An extensive literature regarding atrophic gastritis and its effects on acid secretion, gastric microflora, and its tight association with gastric cancer has been rediscovered, confirmed, and expanded. Methods to stratify cancer risk based on endoscopic and histologic findings or serologic testing of pepsinogen levels and H. pylori testing have been developed producing practical primary and secondary gastric cancer prevention strategies. H. pylori eradication halts progressive mucosal damage. Cure of the infection in those with non-atrophic gastritis will essentially prevent subsequent development of gastric cancer. For all, the age-related progression in cancer risk is halted and likely reduced as eradication reduces or eliminates mucosal inflammation and reverses or reduces H. pylori-associated molecular events such aberrant activation-induced cytidine deaminase expression, double strand DNA breaks, impaired DNA mismatch repair and aberrant DNA methylation. Those who have developed atrophic gastritis/gastric atrophy however retain some residual risk for gastric cancer which is proportional to the extent and severity of atrophic gastritis. Primary and secondary cancer prevention starts with H. pylori eradication and cancer risk stratification to identify those at higher risk who should also be considered for secondary cancer prevention programs. Japan has embarked on population-wide H. pylori eradication coupled with surveillance targeted to those with significant remaining risk. We anticipate that countries with high gastric cancer burdens will follow their lead. We provide specific recommendations on instituting practical primary and secondary gastric cancer prevention programs as well identifying research needed to make elimination of gastric cancer both efficient and cost effective.

Association of CHD5 and KLF5 expression with prognosis in gastric carcinoma Deng Luo, Gong-Fang Zhao, Ming-Liang Lu, Hua Huang, Jiang Chang, Meng-Yao Zheng

AIM: To investigate the expression of chromodomain helicase DNA-binding protein 5 (CHD5) and Krüppel-like factor 5 (KLF5) in gastric cancer, and to evaluate whether CHD5 and KLF5 can be used as prognostic markers in gastric cancer.

METHODS: Immunohistochemistry staining was performed to detect the expression of CHD5 and KLF5 proteins in 208 surgical specimens of gastric cancer and 68 noncancerous gastric tissue specimens. The association of CHD5 and KLF5 expression in gastric cancer with the survival time of patients was retrospectively analyzed.

RESULTS: Reduced expression of CHD5 and KLF5 frequently occurred in gastric cancer. The positive rates of CHD5 and KLF5 expression in gastric cancer were 29.33% (61/208) and 38.46% (80/208), respectively. CHD5 expression was correlated with age, histologic differentiation, depth of invasion, regional lymph node metastasis, distant metastasis, and TNM stage (all P < 0.05). KLF5 expression was correlated with histologic differentiation, depth of invasion, lymph node metastasis, distant metastasis, and TNM stage (all P < 0.05). Further multivariate analysis revealed that patient's gender, tumor location, histologic differentiation, distant metastasis, TNM stage, and expression of CHD5 and KLF5 were independent prognostic factors in patients with gastric cancer. The Kaplan-Meier plot showed that the median survival was 21.00 ± 1.36 months in patients with negative expression of CHD5 and 20.00 ± 1.54 months in those with negative expression of KLF5. The median survival time was 55.00 ± 6.97 months in patients with positive CHD5 expression and 45.00±3.27 months in patients with positive KLF5 expression. The cumulative 1- and 3-year survival rates were significantly lower in patients with negative expression of CHD5 and KLF5 than in those with positive expression of these two proteins.

CONCLUSION: Reduced expression of CHD5 and KLF5 in gastric cancer is associated with tumor metastasis and poor survival. Ectopic expression of CHD5 and KLF5 proteins may play an important role in the tumorigenesis and progression of gastric carcinoma.