Krüppel-like factor 6 participates in extravillous trophoblast cell differentiation and its expression is reduced in abnormally invasive placenta.

Trophoblast cell differentiation is of paramount importance for successful pregnancy. Krüppel-like factor 6 (KLF6), a transcription factor with diverse roles in cell physiology and tumor biology, is required for trophoblast differentiation through the syncytial pathway. Herein, we demonstrate that extravillous trophoblast (EVT) cell migration and mesenchymal phenotype are increased upon KLF6 downregulation or the expression of a deletion mutant lacking its transcriptional regulatory domain (KΔac). Raman spectroscopy revealed molecular modifications compatible with increased differentiation in cells stably expressing the KΔac mutant. Moreover, abnormally invasive placenta showed lower KLF6 immunostaining compared with the normal placenta. Thus, impaired KLF6 expression or function stimulates EVT migration and differentiation in vitro and may contribute to the physiopathology of the abnormally invasive placenta.

Predictive value of transcriptional expression of Krüppel-like factor-6 (KLF6) in head and neck carcinoma patients treated with radiotherapy.

PURPOSE: To analyse the relationship between the transcriptional expression of Krüppel-like factor-6 (KLF6) and local response to treatment with radiotherapy in patients with head and neck squamous cell carcinoma (HNSCC). METHODS: We determined the transcriptional expression of KLF6 in tumour biopsies obtained before treatment with radiotherapy in 83 HNSCC patients. The KLF6 expression was categorized according to the local control of the disease with a recursive partitioning analysis. RESULTS: During the follow-up period, 27 patients (32.5%) had a local recurrence of the tumour. Patients with local recurrence had significantly higher levels of KLF6 expression than patients in which radiotherapy achieved local control of the disease (P = 0.029). Five-year local recurrence-free survival for patients with a high transcriptional expression of KLF6 (n = 46) was 51.1% (95% CI 36.4-66.2%), and for patients with low expression it was 85.6% (95% CI 73.9-97.3%) (P = 0.0001). The results of a multivariate analysis showed that patients with a high KLF6 expression had a 3.8 times higher risk of local recurrence after treatment with radiotherapy (95% CI 1.4-10.5, P = 0.008). CONCLUSION: Transcriptional expression of KLF6 was significantly related to local control in HNSCC patients treated with radiotherapy. Patients with high levels of KLF6 expression had a significantly higher risk of local recurrence after treatment.

Krüppel-Like Factor 6 Is Required for Oxidative and Oncogene-Induced Cellular Senescence.

Krüppel-like factor 6 (KLF6) is a transcription factor involved in the regulation of several cellular processes. Regarding its role in tumorigenesis, KLF6 is considered a tumor suppressor. Numerous reports demonstrate its frequent genomic loss or down-regulation, implying a functional inactivation in a broad range of human cancers. Previous work from our laboratory showed that the down-regulation of KLF6 expression in normal fibroblasts leads to cellular transformation, while its ectopic expression interferes with the oncogenic transformation triggered by activated Ras through a cell cycle arrest. We hypothesize that the growth suppressor activity of KLF6 may involve the induction of cellular senescence thereby helping to prevent the proliferation of cells at risk of neoplastic transformation. Here, we explored the association of KLF6 up-regulation in two different cellular senescence scenarios. We found that KLF6 silencing bypasses both oxidative and oncogene-induced senescence. In this context, KLF6 expression per se was capable to trigger cellular senescence in both normal and tumoral contexts. As such, the findings presented in this report provide insights into a potential mechanism by which KLF6 may play a suppressing role of uncontrolled or damaged cell proliferation.

Rosiglitazone role in the expression of KLF6 caco-2 colon cancer cells / Rol de rosiglitazona en la expresión de KLF6 en células caco-2 de cáncer de colon

Kruppel-like factor 6 (KLF6) is a member of the family of Kruppel transcription factors, this plays an important role in the regulation of cell growth, differentiation and angiogenesis. Rosiglitazone is a PPARy agonist drug, its antitumor effect has been described in models of breast and colon cancer. The aim of this study is to evaluate the level of expression of KLF6 in Caco2 cells treated with Avandia. For this a Immunofluorescence was performed, the Caco2 cells were cultured and treated with Rosiglitazone, another group was treated with Rosiglitazone and GW-9662, inhibitor for Immunofluorescence an anti-KLF6 antibody and a secondary antibody coupled to Alexa-488 was used . Cells were observed in a fluorescence microscope and images were processed. The results show that KLF6 is expressed in the cytoplasm of cells Caco2. Compared to treatment with Avandia, KLF6 increases its expression in the cytoplasm. When cells were treated with GW-9662 inhibitor, an expression of KLF6 in the nucleus was observed. KLF6 expression in the cytoplasm of cells Caco2, could be explained by the knowledge of splicing variants SV1 and SV2, these abnormally accumulate in the cytoplasm and promotes cell growth. It is concluded that in untreated Caco 2 cells, KLF6 is expressed in the cytoplasm. Compared to treatment with Rosiglitazone, KLF6 upregulated in the cytoplasm and compared to treatment with the inhibitor, KLF6 is expressed in the nucleus of Caco 2 cells.

Kruppel-like factor 6 (KLF6) is a member of the family of Kruppel transcription factors, this plays an important role in the regulation of cell growth, differentiation and angiogenesis. Rosiglitazone is a PPARy agonist drug, its antitumor effect has been described in models of breast and colon cancer. The aim of this study is to evaluate the level of expression of KLF6 in Caco2 cells treated with Avandia. For this a Immunofluorescence was performed, the Caco2 cells were cultured and treated with Rosiglitazone, another group was treated with Rosiglitazone and GW-9662, inhibitor for Immunofluorescence an anti-KLF6 antibody and a secondary antibody coupled to Alexa-488 was used . Cells were observed in a fluorescence microscope and images were processed. The results show that KLF6 is expressed in the cytoplasm of cells Caco2. Compared to treatment with Avandia, KLF6 increases its expression in the cytoplasm. When cells were treated with GW-9662 inhibitor, an expression of KLF6 in the nucleus was observed. KLF6 expression in the cytoplasm of cells Caco2, could be explained by the knowledge of splicing variants SV1 and SV2, these abnormally accumulate in the cytoplasm and promotes cell growth. It is concluded that in untreated Caco 2 cells, KLF6 is expressed in the cytoplasm. Compared to treatment with Rosiglitazone, KLF6 upregulated in the cytoplasm and compared to treatment with the inhibitor, KLF6 is expressed in the nucleus of Caco 2 cells.

The activation of peroxisome proliferator-activated receptor γ is regulated by Krüppel-like transcription factors 6 & 9 under steatotic conditions.

Liver steatosis is characterised by lipid droplet deposition in hepatocytes that can leads to an inflammatory and fibrotic phenotype. Peroxisome proliferator-activated receptors (PPARs) play key roles in energetic homeostasis by regulating lipid metabolism in hepatic tissue. In adipose tissue PPARγ regulates the adipocyte differentiation by promoting the expression of lipid-associated genes. Within the liver PPARγ is up-regulated under steatotic conditions; however, which transcription factors participate in its expression is not completely understood. Krüppel-like transcription factors (KLFs) regulate various cellular mechanisms, such as cell proliferation and differentiation. KLFs are key components of adipogenesis by regulating the expression of PPARγ and other proteins such as the C-terminal enhancer binding protein (C/EBP). Here, we demonstrate that the transcript levels of Klf6, Klf9 and Pparγ are increased in response to a steatotic insult in vitro. Chromatin immunoprecipitation (ChIp) experiments showed that klf6 and klf9 are actively recruited to the Pparγ promoter region under these conditions. Accordingly, the loss-of-function experiments reduced cytoplasmic triglyceride accumulation. Here, we demonstrated that KLF6 and KLF9 proteins directly regulate PPARγ expression under steatotic conditions.

Papel de KLF6, como factor de predicción precoz en cáncer colorrectal humano / Role of KLF6 as early predictor in human colorectal cancer

El cáncer colorrectal (CCR) constituye el segundo tipo de cáncer más frecuente en la población europea. Actualmente no existe biomarcadores moleculares que se pueden utilizar para la detección temprana del cáncer de CCR. KLF6 es un supresor tumoral relacionado con varios tipos de cánceres. Nuestra hipótesis plantea que KLF6 puede ser un excelente marcador en el diagnóstico precoz de CCR. Para estudiar la implicancia de KLF6 en el CCR, se seleccionaron 15 biopsias de cada estadio (T1,T2 y T3) de los archivos del Servicio de Anatomía Patológica del Hospital Central de la Defensa Gómez-Ulla, las cuales presentaban áreas de tejido afectado (tumor) y áreas sin afectación (no tumorales). Para ello se realizó un estudio histológico, inmunohistoquímico y RT-PCR, basada en la expresión de 3 genes, Ki67 y p53 como marcadores positivos y KLF6 como marcador en estudio. Los resultados mostraron que la expresión de KLF6 está directamente relacionada con el aumento de la malignidad celular en los adenocarcinomas, corroboradas por las RT-PCR, observándose la aparición progresiva de formas de procesado alternativo, no correspondiente a KLF6. Esta proteína, se expresó tanto a nivel citoplasmático como nuclear en los primeros estadios T1 y T2, para desaparecer a nivel nuclear en el estadio más avanzado (T3). Concluimos que KLF6 es un buen marcador tumoral de CCR, debido a que muestra patrones crecientes de expresión a nivel citoplasmático y decrecientes a nivel nuclear...

Colorectal cancer (CRC) is the second most common type of cancer in the European population. Currently there molecular biomarkers that can be used for early detection of cancer of CRC. Is a tumor suppressor KLF6 associated with several types of cancers. Our hypothesis is that KLF6 can be an excellent marker for the early diagnosis of CRC. To study the implication of KLF6 in CRC, we selected 15 biopsies of each stage (T1, T2 and T3) from the archives of the Pathology Department of Defense Central Hospital Gómez-Ulla, which had areas of affected tissue (tumor) and unaffected areas (non-tumor). This study was performed histological, immunohistochemical and RT-PCR, based on the expression of three genes, markers Ki67 and p53 as positive and as a marker in KLF6 study. The results showed that the expression of KLF6 is directly related to increased malignancy cell adenocarcinomas, corroborated by RT-PCR, showing the gradual emergence of alternative forms processing, corresponding to no KLF6. This protein was expressed both cytoplasmic and nuclear in the early stages T1 and T2, disappearing at the nuclear level in the most advanced stage (T3). KLF6 conclude that a good CRC tumor marker because it shows patterns of expression level increased cytoplasmic and nuclear level decreasing...