Arteriosclerosis ; Humans ; Kruppel-Like Transcription Factors

Blood Vessels ; physiology ; Humans ; Kruppel-Like Transcription Factors ; metabolism ; physiology

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

Krüppel-like factor 7 (KLF7), a member of Krüppel-like transcription factors (KLFs), also known as ubiquitous Krüppel- like factor (UKLF), is ubiquitously expressed in various tissues of adult human beings. Genetics reports showed that the genetic polymorphism of KLF7 is associated with obesity, type 2 diabetes, mental development in human beings; and KLF7 methylation is associated with the development of diffuse gastric cancer (gastric adenocarcinoma). In addition, some genomics reports suggested that KLF7 is one of the key transcription factors in the regulatory networks of serum markers change during the cardiovascular disease. The function studies showed that KLF7 is involved in the regulation of the development and function of the nervous system and adipose tissue, type 2 diabetes, blood diseases, as well as pluripotent cells maintenance. This review summarizes the research progress of KLF7 in genetic characteristics, protein structure and gene function.
Diabetes Mellitus, Type 2 ; Humans ; Kruppel-Like Transcription Factors ; metabolism ; Nervous System ; Obesity

OBJECTIVETo study the frequency of rare blood group Lu(a-b-) phenotype in a population from Shanghai region, and to explore the molecular basis of Lu(a-b-) by detecting the Lu and Lu relative mediator gene EKLF/KLF1.

METHODSDonors from Shanghai region were screened for Lutheran blood group by monoclonal anti-Lub using serological methods. Individuals with Lu(b-) were determined Lua, P1 and i antigens. Fifteen exons of the LU gene and 3 exons of the EKLF/KLF1 gene for the identified Lu(a-b-) samples were amplified and sequenced.

RESULTSTen Lu(a-b-) donors were obtained from 44 331 donors from Shanghai region. No homozygous or heterozygous mutations were found in the LU gene, whilst 7 mutations in EKLF/KLF1 gene were identified in the 10 samples.

CONCLUSIONThe frequency of rare Lu(a-b-) blood group in Shanghai was approximately 0.02%, and all the individuals had an In(Lu) phenotype. The molecular basis of such samples may be related to mutations in the EKLF/KLF1 gene.

China ; ethnology ; Humans ; Kruppel-Like Transcription Factors ; genetics ; Lutheran Blood-Group System ; genetics ; Mutation ; Phenotype

This study was aimed to construct a recombinant adenovirus vector for antisense klf4 gene through AdEasy system. Human klf4 cDNA was reversely inserted into the multiple cloning sites (MCS)of the pShuttle-CMV by using the backbone plasmid AdEasy-l, the antisense klf4 gene was constructed through homologous recombination in E.coli BJ5183, then the adenoviruses were packaged and amplified in the HEK 293 ce1ls. The adenovirus vector for antisense klf4 gene confirmed by PCR, restriction analysis and DNA sequencing. After being transfected with the adenoviruses at 200 MOI for 48 hours, total RNA and protein were extracted from human umbilical vein endothelial cells (HUVEC). Klf4 mRNA and KLF4 protein expression levels were evaluated by Real-time PCR and Western-blot. The results showed that the recombinant adenovirus vector for antisense klf4 gene was successfully constructed, recombinant adenovirus could suppress the expression of klf4 mRNA and KLF4 protein in HUVECs. It is concluded that the adenovirus vector for antisense klf4 gene has been constructed successfully, which provides the material basis for further studying the biologic function and potential application of klf4.
Adenoviridae ; genetics ; Antisense Elements (Genetics) ; Genetic Vectors ; Humans ; Kruppel-Like Transcription Factors ; genetics ; Plasmids ; Transfection

Overexpression of Krüppel like factor 2 (Klf2) or Klf7 inhibits adipocyte formation. However, it remains unclear whether Klf2 regulates klf7 expression in adipose tissue. In this study, oil red O staining and Western blotting were employed to study the effect of Klf2 overexpression on the differentiation of chicken preadipocytes. The results showed that Klf2 overexpression inhibited the differentiation of chicken preadipocytes induced by oleate and the expression of pparγ, while promoted klf7 expression in chicken preadipocytes. Spearman correlation analysis was used to study the correlation between the expression data of klf2 and klf7 in the adipose tissue of both human and chicken. The results showed that there was a significantly positive correlation between the expression of klf2 and klf7 in adipose tissues (r > 0.1). Luciferase reporter assay showed that overexpression of Klf2 significantly promoted the activity of chicken klf7 promoter (-241/-91, -521/-91, -1 845/-91, -2 286/-91, -1 215/-91; P < 0.05). In addition, the activity of klf7 promoter (-241/-91) reporter in chicken preadipocytes was significantly positively correlated with the amount of klf2 overexpression plasmid transfected (T_au=0.917 66, P=1.074×10^-7). Moreover, Klf2 overexpression significantly promoted the mRNA expression of klf7 in chicken preadipocytes (P < 0.05). In conclusion, upregulation of klf7 expression might be one of the pathways that Klf2 inhibits chicken adipocyte differentiation, and the sequence from -241 bp to -91 bp upstream chicken klf7 translation start site might mediate the regulation of Klf2 on klf7 transcription.
Animals ; Humans ; Chickens/genetics* ; Kruppel-Like Transcription Factors/metabolism* ; Transcription Factors/metabolism* ; Adipocytes/metabolism* ; Adipose Tissue/metabolism*

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 ; Kruppel-Like Transcription Factors/*biosynthesis ; Kruppel-Like Transcription Factors/genetics ; Liver/metabolism ; Liver Neoplasms/*metabolism ; Proto-Oncogene Proteins/*biosynthesis ; Proto-Oncogene Proteins/genetics ; RNA, Messenger/biosynthesis ; RNA, Messenger/genetics ; Reverse Transcriptase Polymerase Chain Reaction

OBJECTIVE: To observe the effect of Krüppel-like factor 4 (KLF4) overexpression on heat stress-induced apoptosis of Raw264.7 macrophages. METHODS: The fragment containing full length mouse KLF4 cDNA coding sequence was inserted into the pcDNA3.1 vector and Raw264.7 macrophages were transfected with pcDNA3.1-KLF4 plasmids using lipofectamine.The expression of KLF4 was examined by Western blot in the Raw264.7 macrophages stably transfected with pcDNA3.1- KLF4 plasmids. Raw264.7 cells transfected with pcDNA3.1 and pcDNA3.1-KLF4 were exposed to heat stress (42 degrees C) for 1h and recovered at 37 degrees C for 12h. Flow cytometry, Hoechest 33258 staining assay, and DNA ladder assays were performed to assess the apoptosis. RESULTS: The KLF4 overexpressed Raw264.7 macrophages were established. After the heat stress, flow cytometry showed that apoptotic cells increased significantly in KLF4 overexpressed cells compared with the vector control; Hoechest 33258 staining was characterized with classical changes including apoptotic body, and nuclear condensation. Agarose gel electrophoresis showed that "DNA ladder" could be observed clearly. CONCLUSION KLF4 overexpression can increase heat stress-induced apoptosis of Raw264.7 macrophages.
Animals ; Apoptosis ; genetics ; Cell Line ; Genetic Vectors ; Heat-Shock Response ; Kruppel-Like Transcription Factors ; genetics ; Macrophages ; cytology ; Mice ; Plasmids ; Transfection

BACKGROUND/AIMS: Kruppel-like factor 4 (KLF4) is an epithelial-specific transcription factor primarily expressed in the gastrointestinal tract that mediates growth arrest in the colonic epithelium. We tried to find whether KLF4 expression is associated with the progression and differentiation of colorectal cancer. METHODS: We detected KLF4 expression in 109 colorectal specimens (40 normal appearing mucosa, 7 adenomas, and 62 carcinomas) by immunohistochemistry using a tissue microarray. Western blot and RT-PCR analyses were also performed. RESULTS: The upregulation of KLF4 expression in carcinoma tissue was statistically significant (p<0.05) when compared to normal appearing mucosa. The negative and weak positive staining rates in normal appearing mucosa, adenoma, and carcinoma were 42.5%, 71.4%, and 82.3%, respectively, indicating a decreased degree of KLF4 expression over the course of progressive transformation of normal cells into malignant derivatives. KLF4 protein levels showed no correlation with sex, age, or metastatic state (p>0.05), while KLF4 protein expression correlated with the diagnostic stage (p<0.05). Furthermore, strong KLF4 staining was detected in 22.9% (11/48) and 0% (0/14) of well/moderately and poorly differentiated colorectal cancers, respectively. Our results clearly indicate that KLF4 protein expression significantly correlates with the degree of differentiation in colorectal cancers (p<0.05). KLF4 expression in RKO cells is also upregulated by butyrate, an inducer of differentiation. CONCLUSIONS: Downregulation of KLF4 expression may lead to more poorly differentiated tumors.
Adenoma ; Blotting, Western ; Butyrates ; Colon ; Colorectal Neoplasms ; Down-Regulation ; Epithelium ; Gastrointestinal Tract ; Immunohistochemistry ; Kruppel-Like Transcription Factors ; Mucous Membrane ; Transcription Factors ; Up-Regulation