801
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Hsu LS, Chan CP, Chen CJ, Lin SH, Lai MT, Hsu JD, Yeh KT, Soon MS. Decreased Kruppel-like factor 4 (KLF4) expression may correlate with poor survival in gastric adenocarcinoma. Med Oncol 2013; 30:632. [PMID: 24105022 DOI: 10.1007/s12032-013-0632-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Accepted: 06/10/2013] [Indexed: 01/19/2023]
Abstract
Kruppel-like factors (KLFs) play either anti- or pro-proliferation roles in different human cancers. Here, we investigated the expression of KLF4 in gastric cancers and its correlation with clinicopathological parameters and overall survival. KLF4 expression was measured in 118 surgical specimens by immunohistochemical microarray assay. No association of cytoplasmic KLF4 expression with gender, TNM status, stage, survival, and pathological type was found. Using Kaplan-Meier analysis, significantly higher overall survival rate was observed in patients with high cytoplasmic KLF4 expression compared to low cytoplasmic KLF4 expression. Univariate analysis revealed that cytoplasmic KLF4 expression, grade, histological type, lymph node metastasis, and stages were correlated to longer overall survival. Our results suggest that KLF4 may play an anti-oncogenic role in gastric tumorigenesis.
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Affiliation(s)
- Li-Sung Hsu
- Institute of Biochemistry and Biotechnology, Chung Shan Medical University, Taichung, Taiwan
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802
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Abstract
Krüppel-like factors (KLFs) are a family of DNA-binding transcriptional regulators with diverse and essential functions in a multitude of cellular processes, including proliferation, differentiation, migration, inflammation and pluripotency. In this Review, we discuss the roles and regulation of the 17 known KLFs in various cancer-relevant processes. Importantly, the functions of KLFs are context dependent, with some KLFs having different roles in normal cells and cancer, during cancer development and progression and in different cancer types. We also identify key questions for the field that are likely to lead to important new translational research and discoveries in cancer biology.
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Affiliation(s)
- Marie-Pier Tetreault
- Department of Medicine, Gastroenterology Division, University of Pennsylvania Perelman School of Medicine, 913 Biomedical Research Building II/III, 421 Curie Boulevard, Philadelphia PA 19104-6144, USA
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803
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Jiang K, Ren C, Nair VD. MicroRNA-137 represses Klf4 and Tbx3 during differentiation of mouse embryonic stem cells. Stem Cell Res 2013; 11:1299-313. [PMID: 24084696 DOI: 10.1016/j.scr.2013.09.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 09/05/2013] [Accepted: 09/05/2013] [Indexed: 02/01/2023] Open
Abstract
MicroRNA-137 (miR-137) has been shown to play an important role in the differentiation of neural stem cells. Embryonic stem (ES) cells have the potential to differentiate into different cell types including neurons; however, the contribution of miR-137 in the maintenance and differentiation of ES cells remains unknown. Here, we show that miR-137 is mainly expressed in ES cells at the mitotic phase of the cell cycle and highly upregulated during differentiation. We identify that ES cell transcription factors, Klf4 and Tbx3, are downstream targets of miR-137, and we show that endogenous miR-137 represses the 3' untranslated regions of Klf4 and Tbx3. Transfection of ES cells with mature miR-137 RNA duplexes led to a significant reduction in cell proliferation and the expression of Klf4, Tbx3, and other self-renewal genes. Furthermore, we demonstrate that increased miR-137 expression accelerates differentiation of ES cells in vitro. Loss of miR-137 during ES cell differentiation significantly impeded neuronal gene expression and morphogenesis. Taken together, our results suggest that miR-137 regulates ES cell proliferation and differentiation by repressing the expression of downstream targets, including Klf4 and Tbx3.
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Affiliation(s)
- Ke Jiang
- Department of Neurology, Mount Sinai School of Medicine, New York, NY 10029, USA
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804
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Sureban SM, May R, Qu D, Weygant N, Chandrakesan P, Ali N, Lightfoot SA, Pantazis P, Rao CV, Postier RG, Houchen CW. DCLK1 regulates pluripotency and angiogenic factors via microRNA-dependent mechanisms in pancreatic cancer. PLoS One 2013; 8:e73940. [PMID: 24040120 PMCID: PMC3767662 DOI: 10.1371/journal.pone.0073940] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 07/23/2013] [Indexed: 12/17/2022] Open
Abstract
Stem cell pluripotency, angiogenesis and epithelial-mesenchymal transition (EMT) have been shown to be significantly upregulated in pancreatic ductal adenocarcinoma (PDAC) and many other aggressive cancers. The dysregulation of these processes is believed to play key roles in tumor initiation, progression, and metastasis, and is contributory to PDAC being the fourth leading cause of cancer-related deaths in the US. The tumor suppressor miRNA miR-145 downregulates critical pluripotency factors and oncogenes and results in repressed metastatic potential in PDAC. Additionally, the miR-200 family regulates several angiogenic factors which have been linked to metastasis in many solid tumors. We have previously demonstrated that downregulation of DCLK1 can upregulate critical miRNAs in both in vitro and in vivo cancer models and results in downregulation of c-MYC, KRAS, NOTCH1 and EMT-related transcription factors. A recent report has also shown that Dclk1 can distinguish between normal and tumor stem cells in Apc (min/+) mice and that ablation of Dclk1(+) cells resulted in regression of intestinal polyps without affecting homeostasis. Here we demonstrate that the knockdown of DCLK1 using poly(lactide-co-glycolide)-encapsulated-DCLK1-siRNA results in AsPC1 tumor growth arrest. Examination of xenograft tumors revealed, (a) increased miR-145 which results in decreased pluripotency maintenance factors OCT4, SOX2, NANOG, KLF4 as well as KRAS and RREB1; (b) increased let-7a which results in decreased pluripotency factor LIN28B; and (c) increased miR-200 which results in decreased VEGFR1, VEGFR2 and EMT-related transcription factors ZEB1, ZEB2, SNAIL and SLUG. Specificity of DCLK1 post-transcriptional regulation of the downstream targets of miR-145, miR-200 and let-7a was accomplished utilizing a luciferase-based reporter assay. We conclude that DCLK1 plays a significant master regulatory role in pancreatic tumorigenesis through the regulation of multiple tumor suppressor miRNAs and their downstream pro-tumorigenic pathways. This novel concept of targeting DCLK1 alone has several advantages over targeting single pathway or miRNA-based therapies for PDAC.
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Affiliation(s)
- Sripathi M. Sureban
- Department of Medicine, the University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
- Department of Veterans Affairs Medical Center, Oklahoma City, Oklahoma, United States of America
- The Peggy and Charles Stephenson Cancer Center, Oklahoma City, Oklahoma, United States of America
| | - Randal May
- Department of Medicine, the University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
- Department of Veterans Affairs Medical Center, Oklahoma City, Oklahoma, United States of America
| | - Dongfeng Qu
- Department of Medicine, the University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
- Department of Veterans Affairs Medical Center, Oklahoma City, Oklahoma, United States of America
| | - Nathaniel Weygant
- Department of Medicine, the University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Parthasarathy Chandrakesan
- Department of Medicine, the University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Naushad Ali
- Department of Medicine, the University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
- The Peggy and Charles Stephenson Cancer Center, Oklahoma City, Oklahoma, United States of America
| | - Stan A. Lightfoot
- Department of Pathology, the University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
- Department of Veterans Affairs Medical Center, Oklahoma City, Oklahoma, United States of America
| | - Panayotis Pantazis
- COARE Biotechnology Inc., Oklahoma City, Oklahoma, United States of America
| | - Chinthalapally V. Rao
- Department of Medicine, the University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
- The Peggy and Charles Stephenson Cancer Center, Oklahoma City, Oklahoma, United States of America
| | - Russell G. Postier
- Department of Surgery, the University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Courtney W. Houchen
- Department of Medicine, the University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
- Department of Veterans Affairs Medical Center, Oklahoma City, Oklahoma, United States of America
- The Peggy and Charles Stephenson Cancer Center, Oklahoma City, Oklahoma, United States of America
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805
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Yu F, Shi Y, Wang J, Li J, Fan D, Ai W. Deficiency of Kruppel-like factor KLF4 in mammary tumor cells inhibits tumor growth and pulmonary metastasis and is accompanied by compromised recruitment of myeloid-derived suppressor cells. Int J Cancer 2013; 133:2872-83. [PMID: 23737434 DOI: 10.1002/ijc.28302] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Accepted: 05/17/2013] [Indexed: 12/27/2022]
Abstract
Increasing evidence indicates that myeloid-derived suppressor cells (MDSCs) negatively regulate immune responses during tumor progression, inflammation and infection. However, the underlying molecular mechanisms of their development and mobilization remain to be fully delineated. Kruppel-like factor KLF4 is a transcription factor that has an oncogenic function in breast cancer development, but its function in tumor microenvironment, a critical component for tumorigenesis, has not been examined. By using a spontaneously metastatic 4T1 breast cancer mouse model and an immunodeficient NOD/SCID mouse model, we demonstrated that KLF4 knockdown delayed tumor development and inhibited pulmonary metastasis, which accompanied by decreased accumulation of MDSCs in bone marrow, spleens and primary tumors. Mechanistically, we found that KLF4 knockdown resulted in a significant decrease of circulating GM-CSF, an important cytokine for MDSC biology. Consistently, recombinant GM-CSF restored the frequency of MDSCs in purified bone marrow cells incubated with conditioned medium from KLF4 deficient cells. In addition, we identified CXCL5 as a critical mediator to enhance the expression and function of GM-CSF. Reduced CXCL5 expression by KLF4 knockdown in primary tumors and breast cancer cells was correlated with a decreased GM-CSF expression in our mouse models. Finally, we found that CXCL5/CXCR2 axis facilitated MDSC migration and that anti-GM-CSF antibodies neutralized CXCL5-induced accumulation of MDSCs. Taken together, our data suggest that KLF4 modulates maintenance of MDSCs in bone marrow by inducing GM-CSF production via CXCL5 and regulates recruitment of MDSCs into the primary tumors through the CXCL5/CXCR2 axis, both of which contribute to KLF4-mediated mammary tumor development.
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Affiliation(s)
- Fang Yu
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, SC; Department of Nutrition and Food Hygiene, Fourth Military Medical University, Xi'an, China
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806
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Induction of Krüppel-like factor 4 expression in reactive astrocytes following ischemic injury in vitro and in vivo. Histochem Cell Biol 2013; 141:33-42. [DOI: 10.1007/s00418-013-1134-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/30/2013] [Indexed: 10/26/2022]
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807
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Song E, Ma X, Li H, Zhang P, Ni D, Chen W, Gao Y, Fan Y, Pang H, Shi T, Ding Q, Wang B, Zhang Y, Zhang X. Attenuation of krüppel-like factor 4 facilitates carcinogenesis by inducing g1/s phase arrest in clear cell renal cell carcinoma. PLoS One 2013; 8:e67758. [PMID: 23861801 PMCID: PMC3702498 DOI: 10.1371/journal.pone.0067758] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2013] [Accepted: 05/21/2013] [Indexed: 02/07/2023] Open
Abstract
Krüppel-like factor 4 (KLF4) is a transcription factor with diverse functions in various cancer types; however, the function of KLF4 in clear cell renal cell carcinoma (ccRCC) carcinogenesis remains unknown. In this study, we initially examined KLF4 expression by using a cohort of surgically removed ccRCC specimens and cell lines. Results indicated that the transcription and translation of KLF4 were lower in ccRCC tissues than in patient-matched normal tissues. Furthermore, the KLF4 expression was significantly downregulated in the five ccRCC cell lines at protein and mRNA levels compared with that in normal renal proximal tubular epithelial cell lines (HKC). KLF4 downregulation was significantly correlated with tumor stage and tumor diameter. Promoter hypermethylation may contribute to its low expression. In addition, in vitro studies indicated that the KLF4 overexpression significantly inhibited proliferation in human ccRCC cell lines 786-O and ACHN. Moreover, the KLF4 overexpression arrested the cell cycle progress at the G1/S phase transition by upregulating p21WAF1/CIP1 expression and downregulating cyclin D1 expression, KLF4 knockdown in HKC cells did the opposite. In vivo studies confirmed the anti-proliferative effect of KLF4. Our results suggested that KLF4 had an important function in suppressing the growth of ccRCC.
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Affiliation(s)
- Erlin Song
- Department of Urology/State Key Laboratory of Kidney Diseases, Chinese PLA General Hospital/Medical School of Chinese PLA, Beijing, China
- Department of Urology, Chinese PLA 211 Hospital, Harbin, China
| | - Xin Ma
- Department of Urology/State Key Laboratory of Kidney Diseases, Chinese PLA General Hospital/Medical School of Chinese PLA, Beijing, China
| | - Hongzhao Li
- Department of Urology/State Key Laboratory of Kidney Diseases, Chinese PLA General Hospital/Medical School of Chinese PLA, Beijing, China
| | - Peng Zhang
- Department of Urology/State Key Laboratory of Kidney Diseases, Chinese PLA General Hospital/Medical School of Chinese PLA, Beijing, China
| | - Dong Ni
- Department of Urology/State Key Laboratory of Kidney Diseases, Chinese PLA General Hospital/Medical School of Chinese PLA, Beijing, China
| | - Weihao Chen
- Department of Urology/State Key Laboratory of Kidney Diseases, Chinese PLA General Hospital/Medical School of Chinese PLA, Beijing, China
| | - Yu Gao
- Department of Urology/State Key Laboratory of Kidney Diseases, Chinese PLA General Hospital/Medical School of Chinese PLA, Beijing, China
| | - Yang Fan
- Department of Urology/State Key Laboratory of Kidney Diseases, Chinese PLA General Hospital/Medical School of Chinese PLA, Beijing, China
| | - Haigang Pang
- Department of Urology/State Key Laboratory of Kidney Diseases, Chinese PLA General Hospital/Medical School of Chinese PLA, Beijing, China
| | - Taoping Shi
- Department of Urology/State Key Laboratory of Kidney Diseases, Chinese PLA General Hospital/Medical School of Chinese PLA, Beijing, China
| | - Qiang Ding
- Department of Urology/State Key Laboratory of Kidney Diseases, Chinese PLA General Hospital/Medical School of Chinese PLA, Beijing, China
| | - Baojun Wang
- Department of Urology/State Key Laboratory of Kidney Diseases, Chinese PLA General Hospital/Medical School of Chinese PLA, Beijing, China
| | - Yu Zhang
- Department of Urology/State Key Laboratory of Kidney Diseases, Chinese PLA General Hospital/Medical School of Chinese PLA, Beijing, China
| | - Xu Zhang
- Department of Urology/State Key Laboratory of Kidney Diseases, Chinese PLA General Hospital/Medical School of Chinese PLA, Beijing, China
- * E-mail:
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808
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Kong X, Li L, Li Z, Le X, Huang C, Jia Z, Cui J, Huang S, Wang L, Xie K. Dysregulated expression of FOXM1 isoforms drives progression of pancreatic cancer. Cancer Res 2013; 73:3987-96. [PMID: 23598278 DOI: 10.1158/0008-5472.can-12-3859] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The transcription factor Forkhead box M1 (FOXM1) plays important roles in oncogenesis. However, the expression statuses of FOXM1 isoforms and their impact on and molecular basis in oncogenesis are unknown. We sought to determine the identities of FOXM1 isoforms in and the impact of their expression on pancreatic cancer development and progression using human tissues, cell lines, and animal models. Overexpression of FOXM1 mRNA and protein was pronounced in human pancreatic tumors and cancer cell lines. We identified five FOXM1 isoforms present in pancreatic cancer: FOXM1a, FOXM1b, and FOXM1c along with two isoforms tentatively designated as FOXM1b1 and FOXM1b2 because they were closely related to FOXM1b. Interestingly, FOXM1c was predominantly expressed in pancreatic tumors and cancer cell lines, whereas FOXM1a expression was generally undetectable in them. Functional analysis revealed that FOXM1b, FOXM1b1, FOXM1b2, and FOXM1c, but not FOXM1a, promoted pancreatic tumor growth and metastasis. Consistently, FOXM1b, FOXM1b1, FOXM1b2, and FOXM1c activated transcription of their typical downstream genes. Also, Sp1 mechanistically activated the FOXM1 promoter, whereas Krüppel-like factor 4 (KLF4) repressed its activity. Finally, we identified an Sp1- and KLF4-binding site in the FOXM1 promoter and showed that both Sp1 and KLF4 protein bound directly to it. Deletion mutation of this binding site significantly attenuated the transcriptional regulation of the FOXM1 promoter positively by Sp1 and negatively by KLF4. We showed that overexpression of specific FOXM1 isoforms critically regulates pancreatic cancer development and progression by enhancing tumor cell invasion and metastasis. Our findings strongly suggest that targeting specific FOXM1 isoforms effectively attenuates pancreatic cancer development and progression.
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Affiliation(s)
- Xiangyu Kong
- Department of Gastroenterology, Shanghai Changhai Hospital, Second Military Medical University, Shanghai, PR China
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809
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Camacho-Vanegas O, Till J, Miranda-Lorenzo I, Ozturk B, Camacho SC, Martignetti JA. Shaking the family tree: identification of novel and biologically active alternatively spliced isoforms across the KLF family of transcription factors. FASEB J 2012; 27:432-6. [PMID: 23134681 DOI: 10.1096/fj.12-220319] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Alternative splicing represents a unique post-transcriptional mechanism that increases the complexity of the eukaryotic proteome-generating protein isoforms whose functions can be novel, diverse, and/or even antagonistic when compared to its full-length transcript. The KLF family of genes consists of ≥17 members, which are involved in the regulation of numerous critical cellular processes, including differentiation, cell proliferation, growth-related signal transduction, angiogenesis, and apoptosis. Using a strategy based on RT-PCR, selective cloning, and promoter-based assays of cancer-relevant genes, we identify and characterize the existence of multiple biologically active KLF splice forms across the entire family of proteins. We demonstrate biological function for a number of these isoforms. Furthermore, we highlight a possible functional interaction between full-length KLF4 and one of its splice variants in up-regulating cellular proliferation. Taken together, this report identifies for the first time a more complete view of the genomic and proteomic breadth and complexity of the KLF transcription factor family, revealing the existence of highly expressed and biologically active isoforms previously uncharacterized. In essence, knowing that these KLF isoforms exist provides the first step toward understanding the roles of these genes in human health and disease.
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Affiliation(s)
- Olga Camacho-Vanegas
- Department of Genetics and Genomic Sciences, Mt. Sinai School of Medicine, New York, NY 10029, USA
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810
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Le Magnen C, Bubendorf L, Ruiz C, Zlobec I, Bachmann A, Heberer M, Spagnoli GC, Wyler S, Mengus C. Klf4 transcription factor is expressed in the cytoplasm of prostate cancer cells. Eur J Cancer 2012; 49:955-63. [PMID: 23089465 DOI: 10.1016/j.ejca.2012.09.023] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Revised: 09/07/2012] [Accepted: 09/15/2012] [Indexed: 01/09/2023]
Abstract
BACKGROUND Cancer initiation and progression might be driven by small populations of cells endowed with stem cell-like properties. Here we comparatively addressed the expression of genes encoding putative stemness regulators including c-Myc, Klf4, Nanog, Oct4A and Sox2 genes in benign prostatic hyperplasia (BPH) and prostate cancer (PCA). METHODS Fifty-eight PCA and thirty-nine BPH tissues samples were used for gene expression analysis, as evaluated by quantitative real-time polymerase chain reaction (qRT-PCR). The expression of specific Klf4 isoforms was tested by conventional PCR. Klf4 specific antibodies were used for protein detection in a tissue microarray including 404 prostate samples. RESULTS Nanog, Oct4A and Sox2 genes were comparably expressed in BPH and PCA samples, whereas c-Myc and Klf4 genes were expressed to significantly higher extents in PCA than in BPH specimens. Immunohistochemical studies revealed that Klf4 protein is detectable in a large majority of epithelial prostatic cells, irrespective of malignant transformation. However, in PCA, a predominantly cytoplasmic location was observed, consistent with the expression of a differentially spliced Klf4α isoform. CONCLUSION Klf4 is highly expressed at gene and protein level in BPH and PCA tissues but a cytoplasmic location of the specific gene product is predominantly detectable in malignant cells. Klf4 location might be of critical relevance to steer its functions during oncogenesis.
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Affiliation(s)
- Clémentine Le Magnen
- Institute for Surgical Research and Hospital Management, Department of Biomedicine, Basel University Hospital, Basel, Switzerland.
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811
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Li Q, Gao Y, Jia Z, Mishra L, Guo K, Li Z, Le X, Wei D, Huang S, Xie K. Dysregulated Krüppel-like factor 4 and vitamin D receptor signaling contribute to progression of hepatocellular carcinoma. Gastroenterology 2012; 143:799-810.e2. [PMID: 22677193 PMCID: PMC3653768 DOI: 10.1053/j.gastro.2012.05.043] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Revised: 05/24/2012] [Accepted: 05/26/2012] [Indexed: 12/31/2022]
Abstract
BACKGROUND & AIMS Krüppel-like factor 4 (KLF4) is a transcription factor and putative tumor suppressor. However, little is known about its effects in hepatocellular carcinogenesis. We investigated the clinical significance, biologic effects, and mechanisms of dysregulated KLF4 signaling. METHODS We performed microarray analysis of hepatocellular carcinoma (HCC) tissues. We used molecular biology analyses and animal models to evaluate activation and function of KLF4-vitamin D receptor (VDR) pathway. RESULTS Expression of KLF4 protein was decreased or lost in primary HCC samples, in particular, lymph node metastases, compared with normal liver tissues. Loss of KLF4 from primary tumors was significantly associated with reduced survival time and was identified as a prognostic marker. Most human HCC cell lines had losses or substantial decreases in levels of KLF4. Exogenous expression of KLF4 in HCC cells upregulated expression of mesenchymal-epithelial transition (MET) and inhibited their migration, invasion, and proliferation in vitro. When these cells were injected into mice, tumors grew more slowly and metastasis was inhibited, compared with HCC cells that did not express KLF4. VDR is a direct transcriptional target of KLF4; we identified 2 sites in the VDR promoter that bound specifically to KLF4. Increased expression of VDR sensitized tumor cells to the inhibitory effects of vitamin D. CONCLUSIONS KLF4 binds to the promoter of VDR to regulate its expression; levels of KLF4 are reduced and levels of VDR are increased in HCC cell lines and primary tumor samples. Expression of KLF4 in HCC cells sensitizes them to the anti-proliferative effects of VD3. This pathway might be manipulated to prevent or treat liver cancer.
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MESH Headings
- Animals
- Binding Sites
- Carcinoma, Hepatocellular/genetics
- Carcinoma, Hepatocellular/metabolism
- Carcinoma, Hepatocellular/mortality
- Carcinoma, Hepatocellular/secondary
- Cell Movement
- Cell Proliferation
- Disease Progression
- Epithelial-Mesenchymal Transition
- Female
- Gene Expression Profiling/methods
- Gene Expression Regulation, Neoplastic
- Hep G2 Cells
- Humans
- Immunohistochemistry
- Kruppel-Like Factor 4
- Kruppel-Like Transcription Factors/genetics
- Kruppel-Like Transcription Factors/metabolism
- Liver Neoplasms/genetics
- Liver Neoplasms/metabolism
- Liver Neoplasms/mortality
- Liver Neoplasms/pathology
- Lymphatic Metastasis
- Mice
- Mice, Inbred BALB C
- Mice, Nude
- Neoplasm Invasiveness
- Oligonucleotide Array Sequence Analysis
- Prognosis
- Promoter Regions, Genetic
- Receptors, Calcitriol/genetics
- Receptors, Calcitriol/metabolism
- Signal Transduction
- Time Factors
- Tissue Array Analysis/methods
- Transfection
- Tumor Burden
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Affiliation(s)
- Qi Li
- Tumor Institute, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, People's Republic of China; Department of Oncology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, People's Republic of China; Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Yong Gao
- Tumor Institute, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, People's Republic of China; Department of Oncology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, People's Republic of China.
| | - Zhiliang Jia
- Department of Gastrointestinal Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Lopa Mishra
- Department of Gastroenterology and Hepatology and Nutrition, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Kun Guo
- Department of Gastrointestinal Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Zhiwei Li
- Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, Texas; Department of Gastrointestinal Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Xiangdong Le
- Department of Gastrointestinal Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Daoyan Wei
- Department of Gastrointestinal Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Suyun Huang
- Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, Texas; Department of Gastrointestinal Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Keping Xie
- Department of Gastrointestinal Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
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812
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Li J, Zheng H, Wang J, Yu F, Morris RJ, Wang TC, Huang S, Ai W. Expression of Kruppel-like factor KLF4 in mouse hair follicle stem cells contributes to cutaneous wound healing. PLoS One 2012; 7:e39663. [PMID: 22745808 PMCID: PMC3379995 DOI: 10.1371/journal.pone.0039663] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Accepted: 05/29/2012] [Indexed: 12/17/2022] Open
Abstract
Background Kruppel-like factor KLF4 is a transcription factor critical for the establishment of the barrier function of the skin. Its function in stem cell biology has been recently recognized. Previous studies have revealed that hair follicle stem cells contribute to cutaneous wound healing. However, expression of KLF4 in hair follicle stem cells and the importance of such expression in cutaneous wound healing have not been investigated. Methodology/Principal Findings Quantitative real time polymerase chain reaction (RT-PCR) analysis showed higher KLF4 expression in hair follicle stem cell-enriched mouse skin keratinocytes than that in control keratinocytes. We generated KLF4 promoter-driven enhanced green fluorescence protein (KLF4/EGFP) transgenic mice and tamoxifen-inducible KLF4 knockout mice by crossing KLF4 promoter-driven Cre recombinase fused with tamoxifen-inducible estrogen receptor (KLF4/CreER™) transgenic mice with KLF4(flox) mice. KLF4/EGFP cells purified from dorsal skin keratinocytes of KLF4/EGFP transgenic mice were co-localized with 5-bromo-2'-deoxyuridine (BrdU)-label retaining cells by flow cytometric analysis and immunohistochemistry. Lineage tracing was performed in the context of cutaneous wound healing, using KLF4/CreER™ and Rosa26RLacZ double transgenic mice, to examine the involvement of KLF4 in wound healing. We found that KLF4 expressing cells were likely derived from bulge stem cells. In addition, KLF4 expressing multipotent cells migrated to the wound and contributed to the wound healing. After knocking out KLF4 by tamoxifen induction of KLF4/CreER™ and KLF4(flox) double transgenic mice, we found that the population of bulge stem cell-enriched population was decreased, which was accompanied by significantly delayed cutaneous wound healing. Consistently, KLF4 knockdown by KLF4-specific small hairpin RNA in human A431 epidermoid carcinoma cells decreased the stem cell population and was accompanied by compromised cell migration. Conclusions/Significance KLF4 expression in mouse hair bulge stem cells plays an important role in cutaneous wound healing. These findings may enable future development of KLF4-based therapeutic strategies aimed at accelerating cutaneous wound closure.
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Affiliation(s)
- Juan Li
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, South Carolina, United States of America
- Centre for Stem Cell Research and Application, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hai Zheng
- Department of General Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Junfeng Wang
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, South Carolina, United States of America
- Centre for Stem Cell Research and Application, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Fang Yu
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, South Carolina, United States of America
| | - Rebecca J. Morris
- Laboratory of Stem Cells and Cancer, The Hormel Institute, University of Minnesota, Austin, Minnesota, United States of America
| | - Timothy C. Wang
- Division of Digestive and Liver Diseases, Department of Medicine and Irving Cancer Center, Columbia University, New York, New York, United States of America
| | - Shiang Huang
- Centre for Stem Cell Research and Application, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- * E-mail: (WA); (SH)
| | - Walden Ai
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, South Carolina, United States of America
- * E-mail: (WA); (SH)
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813
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Li J, Zheng H, Yu F, Yu T, Liu C, Huang S, Wang TC, Ai W. Deficiency of the Kruppel-like factor KLF4 correlates with increased cell proliferation and enhanced skin tumorigenesis. Carcinogenesis 2012; 33:1239-46. [PMID: 22491752 DOI: 10.1093/carcin/bgs143] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Kruppel-like factor 4 (KLF4) is a transcription factor that is highly expressed in differentiated epithelial cells including that of the skin. It is critical for specification or function of differentiated epithelial cells. Moreover, KLF4 functions either as a tumor suppressor or an oncogene depending on different cellular contexts. However, the role of KLF4 in skin tumorigenesis remains controversial. To address this issue, we first examined KLF4 expression using a cohort of samples from patients with skin squamous cell carcinoma and basal cell carcinoma and found that in 21 of 24 tumor tissues (87.5%), KLF4 expression as assayed by immunohistochemistry was absent when compared with that in normal tissues. In addition, knockdown of KLF4 in human epidermal squamous cell carcinoma SCC13 cells was accompanied by increased cell growth. Further analysis revealed that KLF4 deficiency promoted cell migration and adhesion, which are the important properties of tumor cells. These observations were supported by the effect upon overexpression of KLF4 in SCC13 cells. Furthermore, we generated a novel tamoxifen-inducible KLF4/CreER and KLF4(flox) double transgenic mouse model to examine the role of KLF4 in skin cancer development. Consistent with in vitro studies, KLF4 deficiency increased the ability of migration and adhesion of mouse primary skin keratinocytes. Moreover, KLF4 knockout led to increased cell proliferation and skin carcinogenesis in a classical DMBA/TPA mouse skin cancer model. Taken together, our data suggest that KLF4 inhibits cell proliferation, migration and adhesion and that loss of KLF4 promotes skin tumorigenesis.
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Affiliation(s)
- Juan Li
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, 29208, USA
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814
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Abstract
Induced pluripotent stem cells (iPSCs) hold great promise for autologous cell therapies, but significant roadblocks remain to translating iPSCs to the bedside. For example, concerns about the presumed autologous transplantation potential of iPSCs have been raised by a recent paper demonstrating that iPSC-derived teratomas were rejected by syngeneic hosts. Additionally, the reprogramming process can alter genomic and epigenomic states, so a key goal at this point is to determine the clinical relevance of these changes and minimize those that prove to be deleterious. Finally, thus far few studies have examined the efficacy and tumorigenicity of iPSCs in clinically relevant transplantation scenarios, an essential requirement for the FDA. We discuss potential solutions to these hurdles to provide a roadmap for iPSCs to "jump the dish" and become useful therapies.
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Affiliation(s)
- Bonnie Barrilleaux
- Department of Cell Biology and Human Anatomy, University of California Davis School of Medicine, Sacramento, CA 95817, USA
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815
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Loss of nuclear expression of Krüppel-like factor 4 is associated with poor prognosis in patients with oral cancer. Hum Pathol 2011; 43:1119-25. [PMID: 22209344 DOI: 10.1016/j.humpath.2011.09.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Revised: 09/01/2011] [Accepted: 09/02/2011] [Indexed: 11/22/2022]
Abstract
Krüppel-like factor 4 is not only involved in cell proliferation but also affects cell differentiation and extracellular matrix production via positive and negative regulation of the expression of a wide range of genes. To our knowledge, little information is available regarding the role of Krüppel-like factor 4 in oral squamous cell carcinoma. In this study, we investigated the associations between Krüppel-like factor 4 expression and clinical parameters of oral cancer using immunohistochemical assays in 215 surgical specimens. Compared with positive nuclear Krüppel-like factor 4 expression, we observed that negative nuclear Krüppel-like factor 4 expression was significantly associated with an advanced cancer stage (P = .046), a high tumor recurrence rate (P = .009), and a worse 3-year survival rate in patients with oral cancer (P = .046). Nuclear expression of Krüppel-like factor 4 was shown to have an inverse relationship with Ki67 expression (P = .046). Patients with negative nuclear expression of Krüppel-like factor 4 had significantly worse overall survival rates as defined by the log-rank test (P = .014). Patients with oral cancer with negative nuclear Krüppel-like factor 4 expression in tumor cells had poor prognoses and a 2.5-fold higher death risk. Compared with disease stage (P = .025), negative nuclear Krüppel-like factor 4 expression (P = .006) was an independent prognostic factor. Our results revealed that the loss of nuclear expression of Krüppel-like factor 4 is significantly associated with aggressive clinical manifestations and might be an adverse survival factor.
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816
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Walia B, Satija N, Tripathi RP, Gangenahalli GU. Induced Pluripotent Stem Cells: Fundamentals and Applications of the Reprogramming Process and its Ramifications on Regenerative Medicine. Stem Cell Rev Rep 2011; 8:100-15. [DOI: 10.1007/s12015-011-9279-x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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817
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Lu H, Wang X, Li T, Urvalek AM, Yu L, Li J, Zhu J, Lin Q, Peng X, Zhao J. Identification of poly (ADP-ribose) polymerase-1 (PARP-1) as a novel Kruppel-like factor 8-interacting and -regulating protein. J Biol Chem 2011; 286:20335-44. [PMID: 21518760 PMCID: PMC3121510 DOI: 10.1074/jbc.m110.215632] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Revised: 04/21/2011] [Indexed: 01/28/2023] Open
Abstract
Krüppel-like factor 8 (KLF8) regulates critical gene transcription and cellular events associated with cancer. However, KLF8-interacting proteins remain largely unidentified. Using co-immunoprecipitation (co-IP), mass spectrometry, and GST pulldown assays, we identified poly(ADP-ribose) polymerase-1 (PARP-1) as a novel KLF8-interacting protein. Co-IP and Western blotting indicated that KLF8 is also a PARP-1 substrate. Mutation of the cysteines in the zinc finger domain of KLF8 abolished PARP-1 interaction. Surprisingly, immunofluorescent staining revealed a cytoplasmic mislocalization of KLF8 in PARP-1(-/-) cells or when the interaction was disrupted. This mislocalization was prevented by either PARP-1 re-expression or inhibition of CRM1-dependent nuclear export. Interestingly, co-IP indicated competition between PARP-1 and CRM1 for KLF8 binding. Cycloheximide chase assay showed a decrease in the half-life of KLF8 protein when PARP-1 expression was suppressed or KLF8-PARP-1 interaction was disrupted. Ubiquitination assays implicated KLF8 as a target of ubiquitination that was significantly higher in PARP-1(-/-) cells. Promoter reporter assays and chromatin immunoprecipitation assays showed that KLF8 activation on the cyclin D1 promoter was markedly reduced when PARP-1 was deleted or inhibited or when KLF8-PARP-1 interaction was disrupted. Overall, this work has identified PARP-1 as a novel KLF8-binding and -regulating protein and provided new insights into the mechanisms underlying the regulation of KLF8 nuclear localization, stability, and functions.
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Affiliation(s)
- Heng Lu
- From the Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, Florida 32827
| | - Xianhui Wang
- From the Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, Florida 32827
| | - Tianshu Li
- From the Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, Florida 32827
| | - Alison M. Urvalek
- From the Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, Florida 32827
| | - Lin Yu
- From the Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, Florida 32827
| | - Jieli Li
- the Department of Systems Biology and Translational Medicine, College of Medicine, Texas A&M Health Science Center, Temple, Texas 76504-7105
| | - Jinghua Zhu
- the Center for Functional Genomics, University at Albany, Rensselaer, New York 12144, and
| | - Qishan Lin
- the Center for Functional Genomics, University at Albany, Rensselaer, New York 12144, and
| | - Xu Peng
- the Department of Systems Biology and Translational Medicine, College of Medicine, Texas A&M Health Science Center, Temple, Texas 76504-7105
| | - Jihe Zhao
- From the Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, Florida 32827
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818
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Funel N, Morelli M, Giovannetti E, Del Chiaro M, Pollina LE, Mosca F, Boggi U, Cavazzana A, Campani D. Loss of heterozygosity status of D9S105 marker is associated with downregulation of Krüppel-like factor 4 expression in pancreatic ductal adenocarcinoma and pancreatic intraepithelial lesions. Pancreatology 2011; 11:30-42. [PMID: 21412023 DOI: 10.1159/000322990] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2010] [Accepted: 11/19/2010] [Indexed: 12/11/2022]
Abstract
The transcription factor Krüppel-like factor 4 (KLF4) may act both as an oncogene and a tumor suppressor in a tissue-dependent manner, and further studies on its role in pancreatic ductal adenocarcinoma (PDAC) progression and clinical outcome are warranted. Therefore, we investigated the loss of heterozygosity (LOH) in the 9q22.3-32 region and loss of KFL4 gene expression in epithelial cells from 35 PDAC, 6 pancreatic intraductal neoplasias (PanINs) and 6 normal ducts, isolated by laser microdissection, as well as their correlation with overall survival (OS) in patients treated with gemcitabine in the adjuvant setting. LOH was evaluated with 4 microsatellite markers and in situ hybridization, while KLF4 expression was studied by reverse transcription-PCR and immunohistochemistry. LOH in at least 1 locus was observed in 25 of 35 PDAC cases and in 5 of 6 PanINs, respectively. In particular, the loss of the D9S105 marker was present in 46.9% of PDAC and 83.3% of PanINs, becoming the most deleted marker, while no LOH in D9S105 was observed in normal Wirsung pancreatic duct. Lack of KLF4 mRNA expression was significantly associated with: (1) genomic deletion flanking KLF4 in PDAC and in PanINs (with LOH of D9S105), (2) low-grade PDAC-associated PanIN, (3) lack of KLF4 protein expression, and (4) shorter OS. These results strongly suggest a relationship between D9S105 deletion and downregulation of KLF4 gene expression as an early event in PDAC progression, as well as a possible role of KLF4 as a prognostic biomarker in gemcitabine-treated patients. and IAP.
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Affiliation(s)
- Niccola Funel
- Division of General and Transplantation Surgery, University of Pisa, Pisa, Italy
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