OBJECTIVES: To study the differential genes expression in the early stage of acute renal ischemia-reperfusion injury and explore potential molecular mechanisms. METHODS: The ischemia-reperfusion model was made via clamping renal artery of rat. The microarray detection and bioinformatics analyzing of the genes expression were performed. Differentially expressed genes were screened and related cellular activities and signaling pathways were analyzed in early stage of acute kidney injury. Meanwhile, molecules closely relative to acute kidney injury were explored by establishing a biological network of the differentially expressed genes, and the results were verified by real-time PCR. RESULTS: A total of 151 genes showed differential expression in this study, including 132 up-regulated and 19 down-regulated genes. Cell proliferation, cytokines mediated signaling transduction and immune responses were greatly enriched by GO and KEGG analysis. The results of real-time PCR showed that compared with control groups, three selected genes （ANXA1, PHLDA1 and KLF6） which related to the acute kidney injury had an obvious differential expression in the early stage of disease. The multiple of increase was essentially the same as the multiple detected by microarray. CONCLUSIONS This study shows differential gene expression profile, related biological processes and signaling pathways involved in the early stage of acute kidney injury. ANXA1, PHLDA1 and KLF6 may play a role in the pathogenesis of acute kidney injury.
Acute Kidney Injury/genetics* ; Animals ; Annexin A1/genetics* ; Apoptosis Regulatory Proteins/genetics* ; Gene Expression ; Kidney/pathology* ; Kruppel-Like Factor 6/genetics* ; Rats ; Real-Time Polymerase Chain Reaction ; Reperfusion Injury/genetics* ; Signal Transduction

OBJECTIVETo investigate the regulatory mechanism of the transcription of tumor metastasis suppressor gene TMSG-1.

METHODSLuciferase reporter assay and site-directed mutagenesis were used to analyze the regulatory region of TMSG-1. Electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) were carried out to verify the interaction of KLF6 and Sp1 with the regulatory region of TMSG-1. Co-immunoprecipitation (CoIP) was performed to analyze the interaction between KLF6 and Sp1. TMSG-1 and wt-KLF6 mRNA expressions in cells with different metastatic capacities were quantitated by real-time PCR. Cell invasive capability was determined by Matrigel invasion assay.

RESULTSA 63 bp inducible regulatory region (+59 bp - +123 bp) in exon 1 was identified by luciferase assay using reporter plasmids with a series of TMSG-1 regulatory region deletions. Mutations in KLF6/Sp1 binding sites of this region resulted in a decrease of luciferase activity, while cotransfection with KLF6 or Sp1 expressing plasmids led to a remarkable increase of luciferase activity. EMSA and ChIP demonstrated that KLF6 as well as Sp1 interacted with this region. CoIP also indicated a possible interaction between KLF6 and Sp1 proteins. In the highly metastatic cell sublines, a low level of wild type KLF6 was associated synchronously with a low TMSG-1 level. Prostate carcinoma cells overexpressing KLF6 exhibited a higher TMSG-1 level and a lower invasive capability.

CONCLUSIONSTranscription factor complex of KLF6 and Sp1 may participate in the inducible transcriptional regulation of TMSG-1, and a decreased wild type KLF6 expression is likely associated with a low TMSG-1 level in the highly metastatic cell sublines.

Binding Sites ; genetics ; Cell Line, Tumor ; Electrophoretic Mobility Shift Assay ; Humans ; Immunoprecipitation ; Kruppel-Like Factor 6 ; Kruppel-Like Transcription Factors ; genetics ; metabolism ; Lung Neoplasms ; metabolism ; pathology ; Male ; Membrane Proteins ; genetics ; metabolism ; Mutagenesis, Site-Directed ; Mutation ; Neoplasm Invasiveness ; Prostatic Neoplasms ; metabolism ; pathology ; Proto-Oncogene Proteins ; genetics ; metabolism ; RNA, Messenger ; metabolism ; Sp1 Transcription Factor ; genetics ; metabolism ; Sphingosine N-Acyltransferase ; genetics ; metabolism ; Transcriptional Activation ; Transfection ; Tumor Suppressor Proteins ; genetics ; metabolism

OBJECTIVETo investigate the roles of Kruppel-like factor 6 (KLF6) and its splice variant KLF6V on suppressing growth and inducing differentiation of human hepatocellular carcinoma hepG2 cells.

METHODKLF6V cDNA was amplificated by RT-PCR from human hepatocellular carcinoma (HCC) tissue and then sequenced. The recombinant vectors expressing KLF6 variant (KLF6V) were constructed using molecular clone technology based on established plasmid pcDNA3.1A(-)/wtKLF6. KLF6V or KLF6-transfected HepG2 cells were established after being screened with G418. Growth activity of HepG2/KLF6 or HepG2/KLF6V cells was detected by in vitro MTT assay. Expression of p21WAF1 or cyclin D1 protein was detected by Western blot, and expressions of AFP or ALB protein were measured by radioimmunoassay.

RESULTSA novel alternatively spliced transcript of the human KLF6 gene was found and its sequencing revealed that the variant form of KLF6 lacked 126nt and its encoded protein products had a deletion of 42 aa near the COOH-terminal amino acid in comparison with full-length KLF6. Although KLF6 alternative splicing was present in both normal and cancerous tissues, expression of the KLF6 splice variants seemed to be up-regulated in HCCs tissues. The isoform of KLF6 proteins antagonized the ability of wild-type KLF6 to up-regulate p21 expression or down-regulate cyclin D1 expression and suppress HepG2 cell proliferation. KLF6 gene increased albumin production and decreased alpha fetoprotein production of the cells.

CONCLUSIONThe isoform of KLF6 protein, present in HCC tissue, antagonizes the ability of wild-type KLF6 to suppress cell proliferation and induce cellular differentiation.

Cell Differentiation ; Cell Proliferation ; DNA, Complementary ; Gene Expression Regulation, Neoplastic ; Hep G2 Cells ; Humans ; Kruppel-Like Factor 6 ; Kruppel-Like Transcription Factors ; genetics ; Protein Isoforms ; genetics ; Proto-Oncogene Proteins ; genetics ; Transfection

BACKGROUND AND AIMThe Krüppel-like transcription factor KLF6 is a novel tumor-suppressor gene. It was inactivated in human prostate cancer and other tumors tissue, as the result of frequent mutation and loss of heterozygosity (LOH). However, there is no data reporting the levels of KLF6 both mRNA and protein in hepatocellular carcinomas (HCCs). We therefore detected mutations and expression of KLF6 in HCC tissues and further observed the effect of it on cell growth in HCC cell lines.

METHODSWe analyzed the exon-2 of KLF6 gene by direct DNA sequencing, and detected the expression of KLF6 by RT-PCR and Western blot in 23 HCC tissues and corresponding nontumorous tissues. Loss of growth suppressive effect of the HCC-derived KLF6 mutant was characterized by in vitro growth curves plotted, flow cytometry and Western blotting.

RESULTSKLF6 mutations were found in 2 of 23 HCC tissues and one of mutations was missense. Expression of KLF6 mRNA or protein was down-regulated in 8 (34.7%) or 9 (39.1%) of 23 HCC tissues. Wild-type KLF6 (wtKLF6) inhibited cellular proliferation and prolonged G1-S transition by inducing the expression of p21WAF1 following stable transfection into cultured HepG2 cells, but tumor-derived KLF6 mutant (mKLF6) had no effects.

CONCLUSIONOur findings suggest that KLF6 may be involved in pathogenesis of HCC.

Blotting, Western ; Carcinoma, Hepatocellular ; genetics ; pathology ; Cell Cycle ; Cell Line, Tumor ; Cyclin-Dependent Kinase Inhibitor p21 ; metabolism ; Gene Expression Regulation, Neoplastic ; Humans ; Kruppel-Like Factor 6 ; Kruppel-Like Transcription Factors ; genetics ; Liver Neoplasms ; genetics ; pathology ; Mutation ; Proto-Oncogene Proteins ; genetics ; RNA, Messenger ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Sequence Analysis, DNA ; Transfection

OBJECTIVETo explore the mutated KLF6 gene in hepatocellular carcinoma (HCC) and to characterize its behavior in human hepatocellular carcinoma cell line HepG2.

METHODSWe analyzed the DNA isolated from 23 hepatocellular carcinoma tissues and their adjacent nontumor tissues by polymerase chain reaction (PCR). Direct sequencing was used to establish the incidence of mutation in exon2 of the KLF6 gene. Loss of growth suppressive function of the HCC-derived KLF6 mutants was characterized by in vitro analyzing alteration of cell cycle and MTT assay. Expression of p21WAF1, a possible downstream gene of KLF6, was detected in human hepatocellular carcinoma cell line HepG2 transiently transfected with KLF6 genes.

RESULTSMutations of KLF6 were found in 2 of the 23 (8.7%) hepatocellular carcinomas. The two mutations were located in the transactivation domain and one of them resulted in single amino acid substitution of TGG (W) by GGG (G) at codon 162. Unlike the wild-type KLF6, cancer-derived KLF6 mutants neither suppressed growth nor induced p21WAF1 following transfection into culture cells.

CONCLUSIONSMutations of the KLF6 gene may play a role in the pathogenesis of HCC, but are not the dominating mechanism resulting in inactivation of KLF6 functions. KLF6 suppresses hepatocellular carcinoma cell proliferation partly through upregulating expression of the p21WAF1 gene.

Base Sequence ; Carcinoma, Hepatocellular ; genetics ; pathology ; Cell Line, Tumor ; Cell Proliferation ; Humans ; Kruppel-Like Factor 6 ; Kruppel-Like Transcription Factors ; genetics ; physiology ; Liver Neoplasms ; genetics ; pathology ; Molecular Sequence Data ; Point Mutation ; Proto-Oncogene Proteins ; genetics ; physiology ; Sequence Analysis, DNA

OBJECTIVETo investigate the expressions and clinical implications of kruppel-like factor 6(KLF-6) and APC in human colorectal carcinoma.

METHODSThe expressions of KLF-6 and APC in tumor and normal tissues from 32 patients with colorectal carcinoma were investigated by RT-PCR and immunohistochemical technique.

RESULTSThe expression rates of KLF-6 and APC mRNA were 37.5% and 34.3% in tumor tissue, 96.9% and 93.8% respectively in normal tissues (both P< 0.05). The expression rates of KLF-6 and APC protein were 28.1% and 25.0% in colorectal carcinomas, 81.3% and 84.43% respectively in normal tissues (both P< 0.05). There was a significant correlation between the expressions of KLF-6 and APC in colorectal carcinomas (P < 0.05). The expressions of KLF-6 and APC were significantly correlated with tumor differentiation, depth of infiltration, lymph node metastasis and clinical stage (P< 0.05).

CONCLUSIONDown-regulations of KLF-6 and APC might play an important role in the carcinogenesis, development, metastasis of human colorectal carcinoma.

Adenomatous Polyposis Coli Protein ; genetics ; Colorectal Neoplasms ; genetics ; metabolism ; pathology ; Female ; Gene Expression ; Genes, APC ; Humans ; Intestinal Mucosa ; metabolism ; pathology ; Kruppel-Like Factor 6 ; Kruppel-Like Transcription Factors ; genetics ; Male ; Middle Aged ; Neoplasm Staging ; Proto-Oncogene Proteins ; genetics ; RNA, Messenger ; genetics

OBJECTIVETo observe the effect of KLF6 on prostate cancer cell line PC-3 by transgenic method.

METHODSWe obtained KLF6 cDNA by RT-PCR method from the liver cell, transfected plasmid pEGFP-C, recombinated with KLF6 into PC-3 cells, and used them as a transfection group and a control group. MTT, flow cytometer and immunocytochemical methods were used to observe the effect of anti-oncogene wild type KLF6 on prostate cancer cell line PC-3 by transgenic method for 48 hours.

RESULTSAfter transfected into PC-3 cells, KLF6 enhanced growth suppression, (30.0 +/- 5.4)% in the transfection group and 0% in the control, P < 0.01, apoptosis, (24.3 +/- 2.3)% in the transfection group and (5.2 +/- 0.7)% in the control, P < 0.01, the down-regulation of the expression of cyclin D1, (25.3 +/- 3.7)% in the transfection group and (38.5 +/- 4.6)% in the control, P < 0.05 and Bcl-2, (18.7 +/- 3.2)% in the transfection group, and (41.8 +/- 5.9)% in the control, P < 0.01 in PC-3 cells. It also decreased the ratio of the cell phase G2/M, increased the ratio of G0/G1 from (58.6 +/- 7.3)% in the control to (80.0 +/- 9.8)% in the transfection group, P < 0.05.

CONCLUSIONPC-3 cells transfected with wild type KLF6 can enhance its growth suppression and apoptosis. It shows great potential for the gene therapy of androgen-independent carcinoma of the prostate.

Apoptosis ; physiology ; Cell Cycle ; physiology ; Cell Line, Tumor ; Cyclin D1 ; biosynthesis ; Down-Regulation ; Flow Cytometry ; Humans ; Immunohistochemistry ; Kruppel-Like Factor 6 ; Kruppel-Like Transcription Factors ; genetics ; physiology ; Male ; Prostatic Neoplasms ; metabolism ; pathology ; Proto-Oncogene Proteins ; genetics ; physiology ; Proto-Oncogene Proteins c-bcl-2 ; biosynthesis ; Reverse Transcriptase Polymerase Chain Reaction ; Transfection

To investigate the expression of KLF6mRNA in primary hepatocellular carcinoma (HCC), nomal liver tissues and the tissues adjacent to the cancers, reverse-transcription polymerase chain reaction (RT-PCR) was employed to investigate the expression of the KLF6 gene in HCC, the corresponding adjacent non-cancerous tissues and normal liver tissue. Our results showed that an amplified fragment of 427 bp DNA was detected in 18 of 19 (94.7%) adjacent non-cancerous tissues and normal liver tissue, and in 12 (85.7%) of 14 HCC. There were no significant differences in the levels of KLF6 mRNA between normal liver and liver tumors (P>0.05). It is concluded that KLF6 mRNA is generally expressed in HCC.
Carcinoma, Hepatocellular ; metabolism ; Humans ; Kruppel-Like Factor 6 ; Kruppel-Like Transcription Factors ; biosynthesis ; genetics ; Liver ; metabolism ; Liver Neoplasms ; metabolism ; Proto-Oncogene Proteins ; biosynthesis ; genetics ; RNA, Messenger ; biosynthesis ; genetics ; Reverse Transcriptase Polymerase Chain Reaction

Animals ; Cells, Cultured ; Cyclic AMP Response Element-Binding Protein ; metabolism ; Hepatocytes ; drug effects ; metabolism ; Humans ; Kruppel-Like Factor 6 ; Kruppel-Like Transcription Factors ; NF-kappa B ; metabolism ; Proto-Oncogene Proteins ; RNA, Messenger ; metabolism ; Trans-Activators ; genetics ; metabolism ; Transcription Factor AP-1 ; metabolism ; Transcription Factors ; pharmacology