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Jha K, Kumar A, Bhatnagar K, Patra A, Bhavesh NS, Singh B, Chaudhary S. Modulation of Krüppel-like factors (KLFs) interaction with their binding partners in cancers through acetylation and phosphorylation. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2024; 1867:195003. [PMID: 37992989 DOI: 10.1016/j.bbagrm.2023.195003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 09/05/2023] [Accepted: 11/16/2023] [Indexed: 11/24/2023]
Abstract
Post-translational modifications (PTMs) of transcription factors regulate transcriptional activity and play a key role in essentially all biological processes and generate indispensable insight towards biological function including activity state, subcellular localization, protein solubility, protein folding, substrate trafficking, and protein-protein interactions. Amino acids modified chemically via PTMs, function as molecular switches and affect the protein function and characterization and increase the proteome complexity. Krüppel-like transcription factors (KLFs) control essential cellular processes including proliferation, differentiation, migration, programmed cell death and various cancer-relevant processes. We investigated the interactions of KLF group-2 members with their binding partners to assess the role of acetylation and phosphorylation in KLFs on their binding affinity. It was observed that acetylation and phosphorylation at different positions in KLFs have a variable effect on binding with specific partners. KLF2-EP300, KLF4-SP1, KLF6-ATF3, KLF6-JUN, and KLF7-JUN show stabilization upon acetylation or phosphorylation at variable positions. On the other hand, KLF4-CBP, KLF4-EP300, KLF5-CBP, KLF5-WWP1, KLF6-SP1, and KLF7-ATF3 show stabilization or destabilization due to acetylation or phosphorylation at variable positions in KLFs. This provides a molecular explanation of the experimentally observed dual role of KLF group-2 members as a suppressor or activator of cancers in a PTM-dependent manner.
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Affiliation(s)
- Kanupriya Jha
- Department of Biotechnology, School of Engineering and Applied Sciences, Bennett University, Plot Nos. 8-11, Tech Zone 2, Greater Noida, Uttar Pradesh 201310, India.
| | - Amit Kumar
- Department of Biotechnology, School of Engineering and Applied Sciences, Bennett University, Plot Nos. 8-11, Tech Zone 2, Greater Noida, Uttar Pradesh 201310, India.
| | - Kartik Bhatnagar
- Department of Biotechnology, School of Engineering and Applied Sciences, Bennett University, Plot Nos. 8-11, Tech Zone 2, Greater Noida, Uttar Pradesh 201310, India.
| | - Anupam Patra
- Transcription Regulation Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi 110067, India.
| | - Neel Sarovar Bhavesh
- Transcription Regulation Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi 110067, India.
| | - Bipin Singh
- Department of Biotechnology, School of Engineering and Applied Sciences, Bennett University, Plot Nos. 8-11, Tech Zone 2, Greater Noida, Uttar Pradesh 201310, India; Centre for Life Sciences, Mahindra University, Bahadurpally, Jeedimetla, Hyderabad, Telangana 500043, India.
| | - Sarika Chaudhary
- Department of Biotechnology, School of Engineering and Applied Sciences, Bennett University, Plot Nos. 8-11, Tech Zone 2, Greater Noida, Uttar Pradesh 201310, India.
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Naebi H, Bandegi A, Talebinasab F, Samidoust P, Norollahi SE, Vahidi S, Samadani AA. MUTYH and KLF6 gene expression fluctuations in tumor tissue and tumor margins tissues of colorectal cancer. J Egypt Natl Canc Inst 2022; 34:57. [PMID: 36464752 DOI: 10.1186/s43046-022-00158-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 10/26/2022] [Indexed: 12/05/2022] Open
Abstract
BACKGROUND Colorectal cancer (CRC) is one of the most important cancers in the world, and its prevalence varies depending on the geographical area. Genetically, tumor regeneration in CRC as a multi-step process involves activating mutations in protocogenes and losing the function of tumor suppressor genes as well as DNA repair and recovery genes. Occur in this way, our goal was to investigate the expression of KLF6 genes as a tumor suppressor and MUTYH involved in the DNA repair process in colorectal cancer. METHODS This research was conducted during the years 2019-2018 in Razi Hospital, Rasht. The subjects included 30 tumoral and 30 non-tumoral tissues of colorectal cancer and 20 healthy controls. The real-time PCR method was used to investigate the gene expression. For data analysis by SPSS, parametric statistical tests ANOVA and T test and regression analysis were used and p value values less than 0.05 were considered significant. RESULTS The expression of KLF6 gene in tumoral tissues showed a significant decrease compared to non-tumoral tissues (P = 0.04). Also, the expression of MUTYH gene in tumor tissue showed a significant decrease compared to non-tumoral (P = 0.02) and this decrease in MUTYH gene expression had a significant relationship with increasing tumor stage (P = 0.01). CONCLUSION These findings suggest that decreased expression of KLF6 and MUTYH genes in the study population has a significant relationship with colorectal cancer and can be considered as tumor marker in diagnostic purpose.
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Affiliation(s)
- Hoora Naebi
- Department of Biochemistry, Faculty of Medicine, Semnan University of Medical Sciences, Semnan, Iran.,Student Research Committee, Semnan University of Medical Sciences, Semnan, Iran
| | - Ahmadreza Bandegi
- Department of Biochemistry, Faculty of Medicine, Semnan University of Medical Sciences, Semnan, Iran. .,Cancer Research Center and Department of Immunology, Semnan University of Medical Sciences, Semnan, Iran.
| | - Fereshteh Talebinasab
- Department of Biochemistry, Faculty of Medicine, Semnan University of Medical Sciences, Semnan, Iran.,Student Research Committee, Semnan University of Medical Sciences, Semnan, Iran
| | - Pirouz Samidoust
- Razi Clinical Research Development Unit, Guilan university of medical Sciences, Rasht, Iran
| | - Seyedeh Elham Norollahi
- Cancer Research Center and Department of Immunology, Semnan University of Medical Sciences, Semnan, Iran
| | - Sogand Vahidi
- Medical Biology Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Ali Akbar Samadani
- Guilan Road Trauma Research Center, Guilan University of Medical Sciences, Rasht, Iran.
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Hu K, Ma C, Ma R, Zheng Q, Wang Y, Zhang N, Sun Z. Roles of Krüppel-like factor 6 splice variant 1 in the development, diagnosis, and possible treatment strategies for non-small cell lung cancer. Am J Cancer Res 2022; 12:4468-4482. [PMID: 36381325 PMCID: PMC9641401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 09/21/2022] [Indexed: 06/16/2023] Open
Abstract
Krüppel-like factor 6 (KLF6) is a nuclear transcriptional regulator found in mammalian tissue that has been identified as a tumor suppressor gene in several malignancies. As a result of loss of heterozygosity, DNA methylation, and alternative splicing, it is frequently inactivated in various malignancies. Krüppel-like factor 6 splice variant 1 (KLF6-SV1), Krüppel-like factor 6 splice variant 2, and Krüppel-like factor 6 splice variant 3 alternatively spliced isoforms that emerge from a single nucleotide polymorphism in the KLF6 gene. KLF6-SV1 is generally upregulated in multiple cancers, and its biological function is well understood. Overexpression of KLF6-SV1 inhibits the KLF6 gene function while promoting tumor progression, which is associated with a poor prognosis in patients with various malignancies. We reviewed the progress of KLF6-SV1 research in NSCLC over the last several years to understand the molecular mechanisms of tumorigenesis, tumor development, and therapy resistance. Finally, this review emphasizes the therapeutic potential of small interfering RNA targeted silencing of KLF6-SV1 as a novel strategy for managing chemotherapy resistance in NSCLC patients.
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Affiliation(s)
- Kang Hu
- Department of Thoracic Surgery, Central Hospital Affiliated to Shandong First Medical UniversityJinan 250013, Shandong, China
- School of Clinical Medicine, Weifang Medical UniversityWeifang 261053, Shandong, China
| | - Chao Ma
- School of Clinical Medicine, Weifang Medical UniversityWeifang 261053, Shandong, China
| | - Ruijie Ma
- Cheeloo College of Medicine, Shandong UniversityJinan 250013, Shandong, China
| | - Qiming Zheng
- Cheeloo College of Medicine, Shandong UniversityJinan 250013, Shandong, China
| | - Yepeng Wang
- Department of Thoracic Surgery, Central Hospital Affiliated to Shandong First Medical UniversityJinan 250013, Shandong, China
| | - Nan Zhang
- Department of Breast Disease Center, Central Hospital Affiliated to Shandong First Medical UniversityJinan 250013, Shandong, China
| | - Zhigang Sun
- Department of Thoracic Surgery, Central Hospital Affiliated to Shandong First Medical UniversityJinan 250013, Shandong, China
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Kum Chol Ri, Ri MR, Kim KH, Choe SI, Ri JH, Kim JH, Ri JH. KLF6 Super-enhancer Regulates Cell Proliferation by Recruiting GATA2 and SOX10 in Human Hepatoma Cells. Mol Biol 2022. [DOI: 10.1134/s0026893322030116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Hu K, Zheng QK, Ma RJ, Ma C, Sun ZG, Zhang N. Krüppel-Like Factor 6 Splice Variant 1: An Oncogenic Transcription Factor Involved in the Progression of Multiple Malignant Tumors. Front Cell Dev Biol 2021; 9:661731. [PMID: 33816511 PMCID: PMC8017371 DOI: 10.3389/fcell.2021.661731] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 02/23/2021] [Indexed: 01/03/2023] Open
Abstract
Krüppel-like factor 6 (KLF6) is one of the most studied members of the specificity protein/Krüppel-like factor (SP/KLF) transcription factor family. It has a typical zinc finger structure and plays a pivotal role in regulating the biological processes of cells. Recently, it has been considered to play a role in combatting cancer. Krüppel-like factor 6 splice variant 1 (KLF6-SV1), being one of the alternative KLF6 splicing isoforms, participates in tumor occurrence and development and has the potential to become a new target for molecular targeted therapy, although its action mechanism remains to be determined. The purpose of this article is to provide a comprehensive and systematic review of the important role of KLF6-SV1 in human malignant tumors to provide novel insights for oncotherapy.
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Affiliation(s)
- Kang Hu
- School of Clinical Medicine, Weifang Medical University, Weifang, China
| | - Qing-Kang Zheng
- School of Clinical Medicine, Weifang Medical University, Weifang, China
| | - Rui-Jie Ma
- Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Chao Ma
- School of Clinical Medicine, Weifang Medical University, Weifang, China
| | - Zhi-Gang Sun
- Department of Thoracic Surgery, Jinan Central Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Nan Zhang
- Department of Oncology, Jinan Central Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
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6
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Lakshmanan VK, Ojha S, Jung YD. A modern era of personalized medicine in the diagnosis, prognosis, and treatment of prostate cancer. Comput Biol Med 2020; 126:104020. [PMID: 33039808 DOI: 10.1016/j.compbiomed.2020.104020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 09/23/2020] [Accepted: 09/23/2020] [Indexed: 12/24/2022]
Abstract
The present era is witnessing rapid advancements in the field of medical informatics and modern healthcare management. The role of translational bioinformatics (TBI), an infant discipline in the field of medical informatics, is pivotal in this revolution. The development of high-throughput technologies [e.g., microarrays, next-generation sequencing (NGS)] has propelled TBI to the next stage in this modern era of medical informatics. In this review, we assess the promising translational outcomes of microarray- and NGS-based discovery of genes, proteins, micro RNAs, and other active biological compounds aiding in the diagnosis, prognosis, and therapy of prostate cancer (PCa) to improve treatment strategies at the localized and/or metastatic stages in patients. Several promising candidate biomarkers in circulating blood (miR-25-3p and miR-18b-5p), urine (miR-95, miR-21, miR-19a, and miR-19b), and prostatic secretions (miR-203) have been identified. AURKA and MYCN, novel candidate biomarkers, were found to be specifically expressed in neuroendocrine PCa. The use of BTNL2 gene mutations and inflammasomes as biomarkers in immune function-mediated, inherited PCa has also been elucidated based on NGS data. Although TBI discoveries can benefit clinical performance metrics, the translational potential and the in vivo performance of TBI outcomes need to be verified. In conclusion, TBI aids in the effective clinical management of PCa; furthermore, the fate of personalized/precision medicine mostly relies on the enhanced diagnostic, prognostic, and therapeutic potential of TBI.
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Affiliation(s)
- Vinoth-Kumar Lakshmanan
- Centre for Preclinical and Translational Medical Research (CPTMR), Central Research Facility (CRF), Sri Ramachandra Institute of Higher Education and Research, Porur, Chennai, 600 116, Tamil Nadu, India; Thumbay Research Institute for Precision Medicine, Gulf Medical University, Ajman, 4184, United Arab Emirates.
| | - Shreesh Ojha
- Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, United Arab Emirates
| | - Young Do Jung
- Department of Biochemistry, Chonnam National University Medical School, 160 Baeksuh-Roh, Dong Gu, Gwangju, 61469, Republic of Korea
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Li J, Zhang B, Liu M, Fu X, Ci X, A J, Fu C, Dong G, Wu R, Zhang Z, Fu L, Dong JT. KLF5 Is Crucial for Androgen-AR Signaling to Transactivate Genes and Promote Cell Proliferation in Prostate Cancer Cells. Cancers (Basel) 2020; 12:cancers12030748. [PMID: 32245249 PMCID: PMC7140031 DOI: 10.3390/cancers12030748] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 03/15/2020] [Accepted: 03/17/2020] [Indexed: 01/08/2023] Open
Abstract
Androgen/androgen receptor (AR) signaling drives both the normal prostate development and prostatic carcinogenesis, and patients with advanced prostate cancer often develop resistance to androgen deprivation therapy. The transcription factor Krüppel-like factor 5 (KLF5) also regulates both normal and cancerous development of the prostate. In this study, we tested whether and how KLF5 plays a role in the function of AR signaling in prostate cancer cells. We found that KLF5 is upregulated by androgen depending on AR in LNCaP and C4-2B cells. Silencing KLF5, in turn, reduced AR transcriptional activity and inhibited androgen-induced cell proliferation and tumor growth in vitro and in vivo. Mechanistically, KLF5 occupied the promoter of AR, and silencing KLF5 repressed AR transcription. In addition, KLF5 and AR physically interacted with each other to regulate the expression of multiple genes (e.g., MYC, CCND1 and PSA) to promote cell proliferation. These findings indicate that, while transcriptionally upregulated by AR signaling, KLF5 also regulates the expression and transcriptional activity of AR in androgen-sensitive prostate cancer cells. The KLF5-AR interaction could provide a therapeutic opportunity for the treatment of prostate cancer.
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Affiliation(s)
- Juan Li
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, China (L.F.)
- School of Medicine, Southern University of Science and Technology, 1088 Xueyuan Road, Shenzhen, Guangdong 518055, China;
| | - Baotong Zhang
- Emory Winship Cancer Institute, Department of Hematology and Medical Oncology, Emory University School of Medicine, 1365-C Clifton Road, Atlanta, GA 30322, USA
| | - Mingcheng Liu
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, China (L.F.)
- School of Medicine, Southern University of Science and Technology, 1088 Xueyuan Road, Shenzhen, Guangdong 518055, China;
| | - Xing Fu
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, China (L.F.)
- School of Medicine, Southern University of Science and Technology, 1088 Xueyuan Road, Shenzhen, Guangdong 518055, China;
| | - Xinpei Ci
- Vancouver Prostate Centre, Department of Urologic Sciences, University of British Columbia, Vancouver, BC V6H 3Z6, Canada
| | - Jun A
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, China (L.F.)
- School of Medicine, Southern University of Science and Technology, 1088 Xueyuan Road, Shenzhen, Guangdong 518055, China;
| | - Changying Fu
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, China (L.F.)
- School of Medicine, Southern University of Science and Technology, 1088 Xueyuan Road, Shenzhen, Guangdong 518055, China;
| | - Ge Dong
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, China (L.F.)
| | - Rui Wu
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, China (L.F.)
- School of Medicine, Southern University of Science and Technology, 1088 Xueyuan Road, Shenzhen, Guangdong 518055, China;
| | - Zhiqian Zhang
- School of Medicine, Southern University of Science and Technology, 1088 Xueyuan Road, Shenzhen, Guangdong 518055, China;
| | - Liya Fu
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, China (L.F.)
| | - Jin-Tang Dong
- School of Medicine, Southern University of Science and Technology, 1088 Xueyuan Road, Shenzhen, Guangdong 518055, China;
- Emory Winship Cancer Institute, Department of Hematology and Medical Oncology, Emory University School of Medicine, 1365-C Clifton Road, Atlanta, GA 30322, USA
- Correspondence:
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Ri KC, Kim C, Choe SI, So JH, O SH. The Klf6-related super enhancer regulates Klf6-SV2 expression mediated proliferation in human hepatoma (HepG2) cells. BENI-SUEF UNIVERSITY JOURNAL OF BASIC AND APPLIED SCIENCES 2019. [DOI: 10.1186/s43088-019-0001-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
The Klf6 gene, which belongs to Krüppel-like family of C2H2 zinc finger transcription factors, is greatly related to tumorigenesis via a high rate of somatic mutation in the carcinomas of prostate, liver, colon, stomach, lung, neck, pituitary, and nervous system: Furthermore, the pathways regulating the expressions of Klf6 splice variants termed Klf6-SV1, -SV2, and -SV3 remain obscure although their functional outcomes have been clear. In this study, the functional roles of Klf6 variants in the inhibition of cell proliferation induced by the disruption of Klf6-related super enhancer in human hepatoma (HepG2) cells were evaluated.
Results
As a result, the disruption of Klf6-related super enhancer not only induced the upregulation of Klf6-SV2 but also led to a significant reduction of proliferation in HepG2 cells. In addition, the disruption of Klf6-related super enhancer led to the induction of p21 and Bax genes mediated by the upregulation of Klf6-SV2.
Conclusion
In conclusion, it was demonstrated that Klf6-related super enhancer modulates cell proliferation via the regulation of Klf6-SV2 expression in human hepatoma (HepG2) cells. The results provide the functional significance of Klf6-related super enhancer in understanding the transcriptional regulation mechanism of Klf6.
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Babaei K, Khaksar R, Zeinali T, Hemmati H, Bandegi A, Samidoust P, Ashoobi MT, Hashemian H, Delpasand K, Talebinasab F, Naebi H, Mirpour SH, Keymoradzadeh A, Norollahi SE. Epigenetic profiling of MUTYH, KLF6, WNT1 and KLF4 genes in carcinogenesis and tumorigenesis of colorectal cancer. Biomedicine (Taipei) 2019; 9:22. [PMID: 31724937 PMCID: PMC6855188 DOI: 10.1051/bmdcn/2019090422] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 09/02/2019] [Indexed: 12/13/2022] Open
Abstract
Colorectal cancer (CRC) is distinguished by epigenetic elements like DNA methylation, histone modification, histone acetylation and RNA remodeling which is related with genomic instability and tumor initiation. Correspondingly, as a main epigenetic regulation, DNA methylation has an impressive ability in order to be used in CRC targeted therapy. Meaningly, DNA methylation is identified as one of most important epigenetic regulators in gene expression and is considered as a notable potential driver in tumorigenesis and carcinogenesis through gene-silencing of tumor suppressors genes. Abnormal methylation situation, even in the level of promoter regions, does not essentially change the gene expression levels, particularly if the gene was become silenced, leaving the mechanisms of methylation without any response. According to the methylation situation which has a strong eagerness to be highly altered on CpG islands in carcinogenesis and tumorigenesis, considering its epigenetic fluctuations in finding new biomarkers is of great importance. Modifications in DNA methylation pattern and also enrichment of methylated histone signs in the promoter regions of some certain genes like MUTYH, KLF4/6 and WNT1 in different signaling pathways could be a notable key contributors to the upregulation of tumor initiation in CRC. These epigenetic alterations could be employed as a practical diagnostic biomarkers for colorectal cancer. In this review, we will be discuss these fluctuations of MUTYH, KLF4/6 and WNT1 genes in CRC.
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Affiliation(s)
- Kosar Babaei
- Department of Biology, Islamic Azad University of Tonekabon Branch, Tonekabon, Iran
| | - Roya Khaksar
- Gastrointestinal and Liver Diseases Research Center, Guilan University of Medical Sciences, Rasht, Iran
| | - Tahereh Zeinali
- Gastrointestinal and Liver Diseases Research Center, Guilan University of Medical Sciences, Rasht, Iran
| | - Hossein Hemmati
- Razi Clinical Research Development Unit, Guilan University of Medical Sciences, Rasht, Iran
| | - Ahmadreza Bandegi
- Department of Biochemistry, Faculty of Medicine, Semnan University of Medical Sciences, Semnan, Iran
| | - Pirouz Samidoust
- Razi Clinical Research Development Unit, Guilan University of Medical Sciences, Rasht, Iran
| | - Mohammad Taghi Ashoobi
- Department of Surgery, Poursina Hospital, Guilan University of Medical Sciences, Rasht, Iran
| | - Hooman Hashemian
- Pediatric Diseases Research Center,Guilan University of Medical ciences, Rasht, Iran
| | - Kourosh Delpasand
- School of Medicine, Kurdistan University of Mdical Ciences, Sanandaj, Iran
| | - Fereshteh Talebinasab
- Department of Biochemistry, Faculty of Medicine, Semnan University of Medical Sciences, Semnan, Iran
| | - Hoora Naebi
- Department of Biochemistry, Faculty of Medicine, Semnan University of Medical Sciences, Semnan, Iran
| | - Seyed Hossein Mirpour
- Department of Hematology and Oncology, Razi hospital, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran
| | - Arman Keymoradzadeh
- Gastrointestinal and Liver Diseases Research Center, Guilan University of Medical Sciences, Rasht, Iran
| | - Seyedeh Elham Norollahi
- Gastrointestinal and Liver Diseases Research Center, Guilan University of Medical Sciences, Rasht, Iran
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Neural Transcription Factors in Disease Progression. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1210:437-462. [PMID: 31900920 DOI: 10.1007/978-3-030-32656-2_19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Progression to the malignant state is fundamentally dependent on transcriptional regulation in cancer cells. Optimum abundance of cell cycle proteins, angiogenesis factors, immune evasion markers, etc. is needed for proliferation, metastasis or resistance to treatment. Therefore, dysregulation of transcription factors can compromise the normal prostate transcriptional network and contribute to malignant disease progression.The androgen receptor (AR) is considered to be a key transcription factor in prostate cancer (PCa) development and progression. Consequently, androgen pathway inhibitors (APIs) are currently the mainstay in PCa treatment, especially in castration-resistant prostate cancer (CRPC). However, emerging evidence suggests that with increased administration of potent APIs, prostate cancer can progress to a highly aggressive disease that morphologically resembles small cell carcinoma, which is referred to as neuroendocrine prostate cancer (NEPC), treatment-induced or treatment-emergent small cell prostate cancer. This chapter will review how neuronal transcription factors play a part in inducing a plastic stage in prostate cancer cells that eventually progresses to a more aggressive state such as NEPC.
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Antonopoulou E, Ladomery M. Targeting Splicing in Prostate Cancer. Int J Mol Sci 2018; 19:ijms19051287. [PMID: 29693622 PMCID: PMC5983716 DOI: 10.3390/ijms19051287] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 04/18/2018] [Accepted: 04/23/2018] [Indexed: 12/22/2022] Open
Abstract
Over 95% of human genes are alternatively spliced, expressing splice isoforms that often exhibit antagonistic functions. We describe genes whose alternative splicing has been linked to prostate cancer; namely VEGFA, KLF6, BCL2L2, ERG, and AR. We discuss opportunities to develop novel therapies that target specific splice isoforms, or that target the machinery of splicing. Therapeutic approaches include the development of small molecule inhibitors of splice factor kinases, splice isoform specific siRNAs, and splice switching oligonucleotides.
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Affiliation(s)
- Effrosyni Antonopoulou
- Faculty of Health and Applied Sciences, University of the West of England, Coldharbour Lane, Bristol BS16 1QY, UK.
| | - Michael Ladomery
- Faculty of Health and Applied Sciences, University of the West of England, Coldharbour Lane, Bristol BS16 1QY, UK.
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Yang F, Ma J, Tang Q, Zhang W, Fu Q, Sun J, Wang H, Song B. MicroRNA-543 promotes the proliferation and invasion of clear cell renal cell carcinoma cells by targeting Krüppel-like factor 6. Biomed Pharmacother 2017; 97:616-623. [PMID: 29101805 DOI: 10.1016/j.biopha.2017.10.136] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 10/17/2017] [Accepted: 10/24/2017] [Indexed: 12/31/2022] Open
Abstract
MicroRNA-543 (miR-543) has been suggested as an important regulator of the development and progression of various cancer types. However, the role and biological function of miR-543 in clear cell renal cell carcinoma (ccRCC) remains unclear. Here, we found that miR-543 expression was significantly increased in tumor tissues from ccRCC patients and ccRCC cell lines. We found that overexpression of miR-543 markedly promoted the proliferation and invasion of ccRCC cells, whereas suppression of miR-543 had the opposite effects. Krüppel-like factor 6 (KLF6) was identified as a target gene of miR-543. Furthermore, we found that miR-543 negatively regulates the expression of KLF6 and p21 in ccRCC cells. Overexpression of KLF6 markedly attenuated the oncogenic effect of miR-543 overexpression. Moreover, knockdown of KLF6 significantly reversed the antitumor effect of miR-543 inhibition. Overall, our results demonstrate that miR-543 promotes the proliferation and invasion of ccRCC cells by targeting KLF6 and suggest that miR-543 may serve as a potential therapeutic target for treatment of ccRCC.
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Affiliation(s)
- Fan Yang
- Department of Urology, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710038, China
| | - Jianjun Ma
- Department of Urology, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710038, China
| | - Qisheng Tang
- Department of Urology, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710038, China
| | - Wei Zhang
- Department of Urology, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710038, China
| | - Qiang Fu
- Department of Urology, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710038, China
| | - Jinbo Sun
- Department of Urology, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - He Wang
- Department of Urology, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710038, China.
| | - Bin Song
- Department of Urology, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710038, China.
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Bialkowska AB, Yang VW, Mallipattu SK. Krüppel-like factors in mammalian stem cells and development. Development 2017; 144:737-754. [PMID: 28246209 DOI: 10.1242/dev.145441] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Krüppel-like factors (KLFs) are a family of zinc-finger transcription factors that are found in many species. Recent studies have shown that KLFs play a fundamental role in regulating diverse biological processes such as cell proliferation, differentiation, development and regeneration. Of note, several KLFs are also crucial for maintaining pluripotency and, hence, have been linked to reprogramming and regenerative medicine approaches. Here, we review the crucial functions of KLFs in mammalian embryogenesis, stem cell biology and regeneration, as revealed by studies of animal models. We also highlight how KLFs have been implicated in human diseases and outline potential avenues for future research.
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Affiliation(s)
- Agnieszka B Bialkowska
- Division of Gastroenterology, Department of Medicine, Stony Brook University School of Medicine, Stony Brook, NY 11794-8176, USA
| | - Vincent W Yang
- Division of Gastroenterology, Department of Medicine, Stony Brook University School of Medicine, Stony Brook, NY 11794-8176, USA.,Department of Physiology and Biophysics, Stony Brook University School of Medicine, Stony Brook, NY 11794-8176, USA
| | - Sandeep K Mallipattu
- Division of Nephrology, Department of Medicine, Stony Brook University School of Medicine, Stony Brook, NY 11794-8176, USA
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14
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Wang K, Ren Y, Liu Y, Zhang J, He JJ. miR-4262 Promotes Proliferation and Invasion of Human Breast Cancer Cells Through Directly Targeting KLF6 and KLF15. Oncol Res 2016; 25:277-283. [PMID: 27629257 PMCID: PMC7840800 DOI: 10.3727/096504016x14732514133203] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
miRNAs have been shown to be involved in breast cancer growth and progression. miR-4262 is a potential tumor promoter in human cancers. In this study, we first investigated the role of miR-4262 in the proliferation and invasion of human breast cancer cells. Our results showed that, compared with the adjacent tissues and MCF-10A normal breast epithelial cells, miR-4262 was markedly increased in the breast cancer tissues and five cell lines, including MDA-MB-231, MDA-MB-468, MDA-MB-435, SKBR3, and MCF-7. Then the miR-4262 mimic or oligo anta-miR-4262 was transfected into MDA-MB-231 and MCF-7 breast cancer cell lines. The results showed that the miR-4262 mimic greatly increased the miR-4262 level and the proliferation and invasion of MDA-MB-231 and MCF-7 cells. In contrast, the anta-miR-4262 had a completely opposite effect on miR-4262 expression, cell proliferation, and cell invasion in MDA-MB-231 and MCF-7 cells. Moreover, bioinformatics and luciferase reporter gene assays confirmed that miR-4262 targeted the mRNA 3′-UTR region of KLF6 and KLF15, two characterized tumor suppressor genes. miR-4262 suppressed protein levels of KLF6 and KLF15 in MDA-MB-231 cells, and the suppression could be rescued by the transfection of pcDNA-KLF6 and -KLF15. In conclusion, miR-4262 positively regulates proliferation and invasion of human breast cancer cells via suppression of KLF6 and KLF15.
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Affiliation(s)
- Ke Wang
- Department of Breast Surgery, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, P.R. China
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15
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Kong LM, Yao L, Lu N, Dong YL, Zhang J, Wang YQ, Liu L, Zhang HL, Huang JG, Liao CG. Interaction of KLF6 and Sp1 regulates basigin-2 expression mediated proliferation, invasion and metastasis in hepatocellular carcinoma. Oncotarget 2016; 7:27975-87. [PMID: 27057625 PMCID: PMC5053703 DOI: 10.18632/oncotarget.8564] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 03/26/2016] [Indexed: 02/07/2023] Open
Abstract
Accumulating evidence suggests that the tumor suppressor gene Krüppel-like factor 6 (KLF6) plays important roles in both development and progression of cancer. However, the role of KLF6 in hepatocellular carcinoma (HCC) remains unclear. Cancer-related molecule basigin-2 plays an important role in HCC progression and metastasis. Sp1, one of Sp/KLFs family members, regulates basigin-2 expression in HCC. The involvement of KLFs in basigin-2 regulation and HCC progression and metastasis has not been investigated. We first measured KLF6 expression levels in 50 pairs of HCC and adjacent normal tissues (ANTs) by immunohistochemistry. Specifically, low KLF6 expression but high Sp1 and basigin-2 expression were found in HCC tissues. By contrast, the ANTs showed high KLF6 expression but low Sp1 and basigin-2 expression. Kaplan-Meier analysis showed that higher expression of KLF6 was associated with better overall survival. The survival rate of KLF6-negative patients was lower than that of KLF6-positive patients (P = 0.015). We also found that KLF6 binds to the basigin-2 and Sp1 promoters and decreases their expression. Thus, we identified a microcircuitry mechanism in which KLF6 can repress basigin-2 expression directly by binding to its promoter or indirectly by inhibiting the expression of the transcription factor Sp1 to block gene expression. Additionally, overexpression of KLF6 suppressed the invasion, metastasis and proliferation of HCC cells in vitro and in vivo by targeting basigin-2. Our study provides new evidence that interaction of KLF6 and Sp1 regulates basigin-2 expression in HCC and that KLF6 represses the invasive and metastatic capacities of HCC through basigin-2.
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Affiliation(s)
- Ling-Min Kong
- Department of Cell Biology, National Translational Science Center for Molecular Medicine, Fourth Military Medical University, Xi'an, 710032, P. R. China
| | - Li Yao
- Department of Pathology, Tangdu Hospital, Fourth Military Medical University, Xi'an, 710038, P. R. China
| | - Ning Lu
- Department of Oncology, Urumqi General Hospital of Lanzhou Military Command of PLA, Urumqi, 830000, P. R. China
| | - Ya-Lu Dong
- Department of Oncology, Urumqi General Hospital of Lanzhou Military Command of PLA, Urumqi, 830000, P. R. China
| | - Jing Zhang
- Department of Oncology, Urumqi General Hospital of Lanzhou Military Command of PLA, Urumqi, 830000, P. R. China
| | - Yong-Qiang Wang
- Department of Oncology, Urumqi General Hospital of Lanzhou Military Command of PLA, Urumqi, 830000, P. R. China
| | - Lili Liu
- Department of Oncology, Tangdu Hospital, Fourth Military Medical University, Xi'an, 710038, P. R. China
- Cancer Institute, Fourth Military Medical University, Xi'an, 710038, P. R. China
| | - He-Long Zhang
- Department of Oncology, Tangdu Hospital, Fourth Military Medical University, Xi'an, 710038, P. R. China
- Cancer Institute, Fourth Military Medical University, Xi'an, 710038, P. R. China
| | - Jian-Guo Huang
- Department of Oncology, Urumqi General Hospital of Lanzhou Military Command of PLA, Urumqi, 830000, P. R. China
| | - Cheng-Gong Liao
- Department of Oncology, Urumqi General Hospital of Lanzhou Military Command of PLA, Urumqi, 830000, P. R. China
- Department of Oncology, Tangdu Hospital, Fourth Military Medical University, Xi'an, 710038, P. R. China
- Cancer Institute, Fourth Military Medical University, Xi'an, 710038, P. R. China
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16
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Identification of potential biomarkers for xylene exposure by microarray analyses of gene expression and methylation. Mol Cell Toxicol 2016. [DOI: 10.1007/s13273-016-0003-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Abstract
Although prostate cancer is the most common malignancy to affect men in the Western world, the molecular mechanisms underlying its development and progression remain poorly understood. Like all cancers, prostate cancer is a genetic disease that is characterized by multiple genomic alterations, including point mutations, microsatellite variations, and chromosomal alterations such as translocations, insertions, duplications, and deletions. In prostate cancer, but not other carcinomas, these chromosome alterations result in a high frequency of gene fusion events. The development and application of novel high-resolution technologies has significantly accelerated the detection of genomic alterations, revealing the complex nature and heterogeneity of the disease. The clinical heterogeneity of prostate cancer can be partly explained by this underlying genetic heterogeneity, which has been observed between patients from different geographical and ethnic populations, different individuals within these populations, different tumour foci within the same patient, and different cells within the same tumour focus. The highly heterogeneous nature of prostate cancer provides a real challenge for clinical disease management and a detailed understanding of the genetic alterations in all cells, including small subpopulations, would be highly advantageous.
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Ebrahimi A, Nodushan SMHT, Mousavian A, Mokarizadeh A, Abbasi M, Yahaghi E, Rasaei SM. RETRACTED ARTICLE: Diagnostic and prognostic potentials of KLF6 and HER3 expression alterations in cutaneous malignant melanoma. Tumour Biol 2015; 37:10.1007/s13277-015-4236-y. [PMID: 26474591 DOI: 10.1007/s13277-015-4236-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Affiliation(s)
- Ali Ebrahimi
- Students' Research Committee, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | | | - Alireza Mousavian
- Department of Orthopedics Surgery, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Aram Mokarizadeh
- Cellular and Molecular Research Center and Department of Immunology, Kurdistan University of Medical Sciences, Sanandaj, Iran
| | - Mehdi Abbasi
- School of Medicine, Shahed University, Tehran, Iran
| | - Emad Yahaghi
- Department of Molecular Biology, Baqiyatallah University of Medical Sciences, Tehran, Iran
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19
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Yin C, Zhang J, Shi Z, Sun W, Zhang H, Fu Y. Identification and expression of the target gene emx2 of miR-26a and miR-26b in Paralichthys olivaceus. Gene 2015; 570:205-12. [PMID: 26079439 DOI: 10.1016/j.gene.2015.06.030] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2015] [Revised: 06/05/2015] [Accepted: 06/06/2015] [Indexed: 11/26/2022]
Abstract
MicroRNAs (miRNAs) can regulate specific gene expression by binding to target mRNA further involution to diverse biological processes. Our previous miRNA sequencing showed that pol-miR-26a and pol-miR-26b have a sex-biased expression in ovary and testis of Paralichthys olivaceus (P. olivaceus). And the gene empty spiracles homeobox 2 (emx2) was proposed to be a candidate target by bioinformatics prediction. In this study, we cloned the P. olivaceus emx2 cDNA, including a coding region of 741 bp and a 3'-untranslated region (UTR) of 912 bp and the 5'-UTR of 12 bp. The Emx2 protein is highly conserved and especially its homeodomain region is 100% identical from teleosts to mammals. Real-time PCR results showed that the emx2 is not only highly expressed in embryonic neurula stage and adult brain but also has abundant expression in adult gonad, moreover, it exhibits higher expression in ovary than testis. To determine the relationship between emx2 and miRNAs, a luciferase reporter assay was performed and verified that the emx2 is a common target gene of pol-miR-26a and pol-miR-26b. These data thus helps further clarify that miR-26a and miR-26b are involved in regulating gonad development partially through its target on emx2 expression in P. olivaceus.
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Affiliation(s)
- Cui Yin
- Key laboratory of Freshwater Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Agriculture, Shanghai 201306, China
| | - Junling Zhang
- Key laboratory of Freshwater Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Agriculture, Shanghai 201306, China
| | - Zhiyi Shi
- Key laboratory of Freshwater Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Agriculture, Shanghai 201306, China.
| | - Wenhui Sun
- Key laboratory of Freshwater Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Agriculture, Shanghai 201306, China
| | - Hongmei Zhang
- Key laboratory of Freshwater Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Agriculture, Shanghai 201306, China
| | - Yuanshuai Fu
- Key laboratory of Freshwater Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Agriculture, Shanghai 201306, China
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20
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Human cancer: Is it linked to dysfunctional lipid metabolism? Biochim Biophys Acta Gen Subj 2015; 1850:352-64. [DOI: 10.1016/j.bbagen.2014.11.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 10/27/2014] [Accepted: 11/03/2014] [Indexed: 11/23/2022]
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21
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Ozdemir F, Koksal M, Ozmen V, Aydin I, Buyru N. Mutations and Krüppel-like factor 6 (KLF6) expression levels in breast cancer. Tumour Biol 2014; 35:5219-25. [PMID: 24519062 DOI: 10.1007/s13277-014-1678-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Accepted: 01/22/2014] [Indexed: 11/26/2022] Open
Abstract
The transcription factor KLF6 gene has been identified as a tumor suppressor because of its inactivation in several types of cancers by different mechanisms. However, there are no data in the literature investigating the KLF6 mutation rate and expression levels in breast cancer. Therefore, the present study was conducted in order to investigate whether genetic alterations of KLF6 in association with the KLF6 mRNA expression levels may play a role in breast carcinogenesis. For this purpose, we analyzed alterations of the KLF6 gene by direct sequencing and the mRNA levels by reverse transcription-PCR (RT-PCR). In addition to four different non-coding alterations, one missense and two silent alterations were identified in the coding sequence. Reduced KLF6 expression was observed in 41 (83.67 %) of the 49 breast cancer tumors. These findings suggest that the mutation profile of the KLF6 gene in breast tumors is similar to other cancer types. However, these mutations do not exert any effect on the gene expression rate. Downregulation of KLF6 during the progression of breast cancer is independent of the mutations and occurs by a different mechanism.
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Affiliation(s)
- Filiz Ozdemir
- Cerrahpasa Medical Faculty, Department of Medical Biology, Istanbul University, Kocamustafapasa, Istanbul, 34098, Turkey
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22
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Li L, Lorzadeh A, Hirst M. Regulatory variation: an emerging vantage point for cancer biology. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2013; 6:37-59. [DOI: 10.1002/wsbm.1250] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Luolan Li
- Centre for High-Throughput Biology, Department of Microbiology & Immunology; University of British Columbia; Vancouver, British Columbia Canada
| | - Alireza Lorzadeh
- Centre for High-Throughput Biology, Department of Microbiology & Immunology; University of British Columbia; Vancouver, British Columbia Canada
| | - Martin Hirst
- Centre for High-Throughput Biology, Department of Microbiology & Immunology; University of British Columbia; Vancouver, British Columbia Canada
- Canada's Michael Smith Genome Sciences Centre; BC Cancer Agency; Vancouver, British Columbia Canada
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Mazaris E, Tsiotras A. Molecular pathways in prostate cancer. Nephrourol Mon 2013; 5:792-800. [PMID: 24282788 PMCID: PMC3830904 DOI: 10.5812/numonthly.9430] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2012] [Accepted: 12/17/2012] [Indexed: 01/02/2023] Open
Abstract
Objectives Prostate cancer is a prevalent disease with a high impact on patients’ morbidity and mortality. Despite efforts to profile prostate cancer, the genetic alterations and biological processes that correlate with disease progression remain partially elusive. The purpose of this study is to review the recent evidence relating to the initiation and progression of prostate cancer in relation to the familial correlation of the disease, the genetic aberrations resulting in prostate cancer and the new molecular biology data regarding prostate cancer. Materials and Methods A Medline database search identified all the existing publications on the molecular events associated with the pathogenesis and evolution of prostate cancer. Particular emphasis was given on the specific genetic phenomena associated with prostate cancer. Results Like other cancers, prostate cancer is caused by an accumulation of genetic alterations in a cell that drives it to malignant growth. Specific genes and gene alterations have been suggested to play a role in its development and progression. Aneuploidy, loss of heterozygosity, gene mutations, hypermethylation and inactivation of specific tumour suppressor genes such as GSTpi, APC, MDR1, GPX3 and others have been detected in prostate cancers, but generally only at a low or moderate frequency. The androgen receptor (AR) signalling pathway may play a crucial role in the early development of prostate cancer, as well as in the development of androgen-independent disease that fails to respond to hormone deprivation therapies. Other alterations linked to the transition to hormone-independence include amplification of MYC and increased expression of ERBB2 and BCL2. Inflammatory changes may also contribute to the development of prostate cancer. Conclusion The identification of specific molecular markers for prostate cancer may lead to its earliest detection and better prediction of its behavior. The better understanding of the molecular events affecting prostate cancer progression may result in the introduction of new drugs to target these events thus providing a potential cure and a tool for prevention of this very common disease.
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Affiliation(s)
| | - Alexios Tsiotras
- Urology Department, Lister Hospital, Stevenage, United Kingdom
- Corresponding author: Alexios Tsiotras, Urology Department, Lister Hospital, Stevenage, United Kingdom. Tel: +44-7580348549, Fax: +44-1438515601, E-mail:
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24
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Effects of Kruppel-like factor 6 on osteosarcoma cell biological behavior. Tumour Biol 2013; 34:1097-105. [DOI: 10.1007/s13277-013-0651-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Accepted: 01/03/2013] [Indexed: 01/18/2023] Open
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25
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Chiam K, Ryan NK, Ricciardelli C, Day TK, Buchanan G, Ochnik AM, Murti K, Selth LA, Butler LM, Tilley WD, Bianco-Miotto T. Characterization of the prostate cancer susceptibility gene KLF6 in human and mouse prostate cancers. Prostate 2013; 73:182-93. [PMID: 22782870 DOI: 10.1002/pros.22554] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Accepted: 06/05/2012] [Indexed: 11/06/2022]
Abstract
BACKGROUND Krüppel-like factor (KLF) 6 is a candidate tumor suppressor gene in prostate cancer, but the mechanisms contributing to its loss of expression are poorly understood. We characterized KLF6 expression and DNA methylation status during prostate tumorigenesis in humans and mice. METHODS KLF6 expression was assessed in matched human non-malignant (NM) and tumor prostate tissues (n = 22) by quantitative real-time PCR (qPCR) and in three independent human prostate cancer cohorts bioinformatically. QPCR for KLF6 expression and methylation-sensitive PCR (MSP) were performed in human prostate LNCaP cancer cells after 5-aza-2'-deoxycytidine treatment. Klf6 protein levels and DNA promoter methylation were assessed in TRansgenic Adenocarcinoma of Mouse Prostate (TRAMP) tumors by immunohistochemistry and MSP, respectively. RESULTS KLF6 splice variants expression was increased (P = 0.0015) in human prostate tumors compared to NM tissues. Overall, KLF6 was decreased in metastatic compared to primary prostate cancers and reduced expression in primary tumors was associated with a shorter time to relapse (P = 0.0028). Treatment with the demethylating agent 5-aza-2'-deoxycytidine resulted in up-regulation of KLF6 expression (two-fold; P = 0.002) and a decrease in DNA methylation of the KLF6 promoter in LNCaP cells. Klf6 protein levels significantly decreased with progression in the TRAMP model of prostate cancer (P < 0.05), but there was no difference in Klf6 promoter methylation. CONCLUSION KLF6 expression was decreased in both clinical prostate cancer and the TRAMP model with disease progression, but this could not be explained by DNA methylation of the KLF6 promoter.
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Affiliation(s)
- Karen Chiam
- Dame Roma Mitchell Cancer Research Laboratories and Adelaide Prostate Cancer Research Centre, Discipline of Medicine, The University of Adelaide and Hanson Institute, Adelaide, Australia
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Ma XH, Zhou YF, Zheng PY, Yu Y, Zhang Q, Zhang LQ. Expression of KLF6 in gastric carcinoma and premalignant gastric lesions. Shijie Huaren Xiaohua Zazhi 2012; 20:3683-3688. [DOI: 10.11569/wcjd.v20.i36.3683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To detect the expression of the krüppel-like factor 6 (KLF6) in human gastric carcinoma and premalignant gastric lesions to investigate its role in the occurrence and development of gastric cancer.
METHODS: Fresh frozen gastric carcinoma tissues and matched tumor-adjacent normal gastric mucosa tissues were collected from 32 patients with gastric carcinoma. RT-PCR was used to analyze the expression level of KLF6 mRNA in these tissue samples. Meanwhile, the expression of KLF6 protein was detected by immunohistochemistry in 111 formalin-fixed paraffin-embedded samples, including 20 cases of normal gastric mucosa, 45 cases of intestinal metaplasia, 16 cases of dysplasia, and 30 cases of gastric carcinoma. The association of KLF6 expression with clinicopathological characteristics was analyzed.
RESULTS: The positive rate of KLF6 protein expression in normal gastric mucosa was significantly different from those in type Ⅲ intestinal metaplasia, dysplasia and gastric carcinoma (χ2 = 6.033, 3.889, 11.092, P = 0.014, 0.049, 0.001). The positive rate of KLF6 expression in gastric carcinoma was associated with tumor differentiation and size (P = 0.009, 0.010). There was no significant difference in the expression of KLF6 mRNA between normal gastric mucosa and gastric carcinoma (P = 0.357).
CONCLUSION: Abnormal expression of KLF6 is closely related to type Ⅲ intestinal metaplasia, dysplasia, and gastric carcinoma. Detection of KLF6 expression may have certain value in the surveillance of premalignant lesions and the discovery of early gastric carcinoma.
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Molecular profiling of prostatic acinar morphogenesis identifies PDCD4 and KLF6 as tissue architecture-specific prognostic markers in prostate cancer. THE AMERICAN JOURNAL OF PATHOLOGY 2012; 182:363-74. [PMID: 23219426 DOI: 10.1016/j.ajpath.2012.10.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 10/07/2012] [Accepted: 10/31/2012] [Indexed: 11/18/2022]
Abstract
Histopathological classification of human prostate cancer (PCA) relies on the morphological assessment of tissue specimens but has limited prognostic value. To address this deficiency, we performed comparative transcriptome analysis of human prostatic acini generated in a three-dimensional basement membrane that recapitulates the differentiated morphological characteristics and gene expression profile of a human prostate glandular epithelial tissue. We then applied an acinar morphogenesis-specific gene profile to two independent cohorts of patients with PCA (total n = 79) and found that those with tumors expressing this profile, which we designated acini-like tumors, had a significantly lower risk of postoperative relapse compared with those tumors with a lower correlation (hazard ratio, 0.078; log-rank test P = 0.009). Multivariate analyses showed superior prognostic prediction performance using this classification system compared with clinical criteria and Gleason scores. We prioritized the genes in this profile and identified programmed cell death protein 4 (PDCD4) and Kruppel-like factor 6 (KLF6) as critical regulators and surrogate markers of prostatic tissue architectures, which form a gene signature that robustly predicts clinical prognosis with a remarkable accuracy in several large series of PCA tumors (total n = 161; concordance index, 0.913 to 0.951). Thus, by exploiting the genomic program associated with prostate glandular differentiation, we identified acini-like PCA and related molecular markers that significantly enhance prognostic prediction of human PCA.
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Liu X, Gomez-Pinillos A, Loder C, Carrillo-de Santa Pau E, Qiao R, Unger PD, Kurek R, Oddoux C, Melamed J, Gallagher RE, Mandeli J, Ferrari AC. KLF6 loss of function in human prostate cancer progression is implicated in resistance to androgen deprivation. THE AMERICAN JOURNAL OF PATHOLOGY 2012; 181:1007-16. [PMID: 22819534 DOI: 10.1016/j.ajpath.2012.06.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Revised: 05/14/2012] [Accepted: 06/07/2012] [Indexed: 01/10/2023]
Abstract
Inactivation of the transcription factor/tumor suppressor Krüppel-like factor 6 (KLF6) has been described in prostate cancer (PC). This study investigated the prevalence and significance of KLF6 exon 2 mutations and splice variants (SVs) in different stages of human PC progression. By using laser-capture microdissection and recombinant clone isolation of DNA sequences to enhance sensitivity, base changes were found in 20 (24.7%) of 81 PC tissues versus 1 (4%) of 25 normal prostate tissues (P = 0.02). Of 26 base changes, 54% produced nonsynonymous mutations. Only three mutations had driver characteristics (PCs, 4%; NPs, 0%). By using microdissection of fresh-frozen tissues and recombinant isolation of RNA sequences, SVs were found in 39 (75%) of 52 PCs and in 10 (45%) of 22 NPs (P = 0.01). Sixteen different SVs, including 13 unique SVs, were identified that used cryptic splicing sites and encoded nonfunctional KLF6 proteins. PCs that had survived hormone (androgen)-deprivation therapy (n = 21) had a significantly higher (P < 0.05) incidence, number, and expression level of nonfunctional SVs than either NPs (n = 22) or hormone-naïve PCs (n = 25). Forced expression of nonfunctional SVs conferred a survival advantage of androgen-dependent LNCaP cells under castration-simulated culture conditions. Together, these data suggest that decreased availability of functional KLF6 contributes to clinical PC progression. This decrease arises infrequently by somatic mutation and more commonly by the acquisition of SVs that provide a survival advantage under castrate conditions, enabling resistance to hormone therapy.
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Affiliation(s)
- XiaoMei Liu
- Department of Medicine, New York University Cancer Institute, New York, USA
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Grattan BJ, Freake HC. Zinc and cancer: implications for LIV-1 in breast cancer. Nutrients 2012; 4:648-75. [PMID: 22852056 PMCID: PMC3407987 DOI: 10.3390/nu4070648] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Revised: 06/07/2012] [Accepted: 06/27/2012] [Indexed: 01/21/2023] Open
Abstract
Zinc is a trace mineral which is vital for the functioning of numerous cellular processes, is critical for growth, and may play an important role in cancer etiology and outcome. The intracellular levels of this mineral are regulated through the coordinated expression of zinc transporters, which modulate both zinc influx as well as efflux. LIV-1 (ZIP6) was first described in 1988 as an estrogen regulated gene with later work suggesting a role for this transporter in cancer growth and metastasis. Despite evidence of its potential utility as a target gene for cancer prognosis and treatment, LIV-1 has received relatively little attention, with only three prior reviews being published on this topic. Herein, the physiological effects of zinc are reviewed in light of this mineral’s role in cancer growth with specific attention being given to LIV-1 and the potential importance of this transporter to breast cancer etiology.
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Affiliation(s)
- Bruce J. Grattan
- Department of Family Medicine, Stony Brook University Hospital Medical Center, Stony Brook, New York, NY 11597, USA
- Authors to whom correspondence should be addressed; (B.J.G.); (H.C.F.); Tel.: +1-631-444-8245; Fax: +1-631-444-7552
| | - Hedley C. Freake
- Department of Nutritional Sciences, University of Connecticut, Storrs, CT 06268, USA
- Authors to whom correspondence should be addressed; (B.J.G.); (H.C.F.); Tel.: +1-631-444-8245; Fax: +1-631-444-7552
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Zhang X, Nie Y, Du Y, Cao J, Shen B, Li Y. MicroRNA-181a promotes gastric cancer by negatively regulating tumor suppressor KLF6. Tumour Biol 2012; 33:1589-97. [PMID: 22581522 DOI: 10.1007/s13277-012-0414-3] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Accepted: 04/30/2012] [Indexed: 12/13/2022] Open
Abstract
MicroRNAs have emerged as crucial regulators of tumorigenesis. However, it remains unknown whether miR-181a is involved in the pathogenesis of gastric cancer. In this study, we found that miR-181a is overexpressed in human gastric cancer tissues. Ectopic expression of miR-181a mimic promoted the proliferation, colony formation, migration, and invasion and inhibited the apoptosis of SGC-7901 gastric cancer cells, whereas ectopic expression of miR-181a inhibitor inhibited the malignant phenotypes of SGC-7901 cells. Site-directed mutagenesis and luciferase reporter assay demonstrated that miR-181a repressed KLF6 expression by targeting its 3'-UTR. Western blot analysis further showed that KLF6 protein was significantly decreased or increased when miR-181a mimic or inhibitor was transfected into SGC-7901 cells, respectively. In summary, these data suggest that KLF6 gene is a direct target of miR-181a and miR-181a functions as an oncomir in gastric cancer by repressing the expression of tumor suppressor KLF6.
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Affiliation(s)
- Xiangyang Zhang
- Guangzhou Key Laboratory of Digestive Disease, Department of Gastroenterology, First Municipal People's Hospital of Guangzhou, Guangzhou Medical University, No.1 Panfu Road, Guangzhou, 510180, China
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Su Y, Qu Y, Jiang C, Liu L, Shan Y, Wang F. KLF6SV1 siRNA inhibits proliferation of human lens epithelial cells. Mol Vis 2012; 18:601-5. [PMID: 22419853 PMCID: PMC3298452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Accepted: 02/28/2012] [Indexed: 11/17/2022] Open
Abstract
PURPOSE To investigate whether transfection with Krüppel-like factor 6 splice variant 1 (KLF6SV1) siRNA can inhibit proliferation of human lens epithelial cell (HLEC). METHODS Plasmid containing KLF6SV1 siRNA was used to decrease the level of KLF6SV1 protein in HLEC. The expression of protein27 kinase inhibition protein 1 (p27(kip1)) and proliferation cell nuclear antigen (PCNA) was tested with western blot. Cell proliferation was assayed by 3-(4,5-dimethylthiazolyl-2-)-2,5-diphenyltetrazoliumbromide (MTT) assay and bromodeoxyuridine (BrdU) incorporation. RESULTS KLF6SV1 siRNA can decrease KLF6SV1 expression which leads to increased levels of p27(kip1) and decreased expression of PCNA in HLEC. Cells transfected with pKLF6SV1 siRNA showed less viability compared with the control group in vitro. CONCLUSIONS KLF6SV1 siRNA can effectively inhibit HLEC proliferation. It can be regarded as a novel target to treat posterior capsular opacity (PCO).
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Affiliation(s)
- Ying Su
- Department of Ophthalmology, First clinical college of Harbin Medical University, Harbin, China
| | - Yixin Qu
- Department of Ophthalmology, First clinical college of Harbin Medical University, Harbin, China
| | - Chenggong Jiang
- Department of Ophthalmology, First clinical college of Harbin Medical University, Harbin, China
| | - Lijuan Liu
- Department of Ophthalmology, First clinical college of Harbin Medical University, Harbin, China
| | - Yanchun Shan
- Medical College, Jinan University, Guangzhou, China
| | - Feng Wang
- Department of Ophthalmology, First clinical college of Harbin Medical University, Harbin, China
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A small interfering RNA targeting the KLF6 splice variant, KLF6-SV1, as gene therapy for gastric cancer. Gastric Cancer 2011; 14:339-52. [PMID: 21538018 DOI: 10.1007/s10120-011-0049-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2010] [Accepted: 03/28/2011] [Indexed: 02/07/2023]
Abstract
BACKGROUND Accumulating evidence suggests that the tumor suppressor gene Kruppel-like factor 6 (KLF6) and its dominant-negative splice form KLF6-SV1 play important roles in both the development and progression of cancer. However, the role of KLF6-SV1 in gastric cancer remains largely unknown. METHODS KLF6-SV1 expression was detected in various human gastric cancer cell lines and gastric cancer patient samples by reverse transcriptase polymerase chain reaction (RT-PCR) and Western blotting. Small interfering RNA (siRNA) was used to inhibit KLF6-SV1 expression in BGC-823 and SGC-7901 cell lines. The effects of downregulation of KLF6-SV1 by siRNA on cell proliferation, migration, invasion, and tumor growth were examined in vitro and in vivo. RESULTS Overexpression of KLF6-SV1 was detected in tumor samples from gastric cancer patients, and in various differentiated gastric cancer cell lines. In vitro downregulation of KLF6-SV1 by siRNA inhibited BGC-823 and SGC-7901 cell proliferation, anchorage-independent growth, migration, and invasion through the altered expression of Ki-67, vascular endothelial growth factor (VEGF), E-cadherin, and matrix metalloproteinase (MMP)-9. Also, KLF6-SV1 silencing promoted caspase-dependent apoptosis of BGC-823 and SGC-7901 cells via the regulation of phosphatidylinositol 3-OH kinase (PI3K)/Akt activity and Bcl-2-related protein expression. In vivo animal studies showed that KLF6-SV1 siRNA significantly inhibited the tumorigenicity of BGC-823 and SGC-7901 cells. Gene therapy with polyethylenimine/si-SV1 intratumoral injection also resulted in the suppression of tumor growth and prolonged animal survival in an established xenograft tumor model. CONCLUSION These data demonstrate that KLF6-SV1 is an important regulator of the growth, migration, invasion, and survival of gastric cancer cells, and downregulation of KLF6-SV1 by siRNA may offer a new potential gene therapy approach for gastric cancer.
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Bureau C, Hanoun N, Torrisani J, Vinel JP, Buscail L, Cordelier P. Expression and Function of Kruppel Like-Factors (KLF) in Carcinogenesis. Curr Genomics 2011; 10:353-60. [PMID: 20119532 PMCID: PMC2729999 DOI: 10.2174/138920209788921010] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2009] [Revised: 06/15/2009] [Accepted: 06/18/2009] [Indexed: 11/22/2022] Open
Abstract
Krüppel-like factor (KLF) family members share a three C2H2 zinc finger DNA binding domain, and are involved in cell proliferation and differentiation control in normal as in pathological situations. Studies over the past several years support a significant role for this family of transcription factors in carcinogenesis. KLFs can both activate and repress genes that participate in cell-cycle regulation. Among them, many up-regulated genes are inhibitors of proliferation, whereas genes that promote cell proliferation are repressed. However, several studies do present KLFs as positive regulator of cell proliferation. KLFs can be deregulated in multiple cancers either by loss of heterozygosity (LOH), somatic mutation or transcriptional silencing by promoter hypermethylation. Accordingly, KLF expression was shown to mediate growth inhibition when ectopically expressed in multiple cancer-derived cell lines through the inhibition of a number of key oncogenic signaling pathways, and to revert the tumorogenic phenotype in vivo. Taken together, these observations suggest that KLFs act as tumor suppressor. However, in some occasion, KLFs could act as tumor promoters, depending on “cellular context”. Thus, this review will discuss the roles and the functions of KLF family members in carcinogenesis, with a special focus on cancers from epithelial origin.
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Affiliation(s)
- Christophe Bureau
- Institut National de la Santé et de la Recherche Médicale Unité 858-I2MR, Institut de Médecine Moléculaire de Rangueil, Département Cancers Epithéliaux, Angiogénèse et Signalisation, 31432 Toulouse Cedex 4 France
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Andreoli V, Gehrau RC, Bocco JL. Biology of Krüppel-like factor 6 transcriptional regulator in cell life and death. IUBMB Life 2011; 62:896-905. [PMID: 21154818 DOI: 10.1002/iub.396] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
An essential role for the Krüppel-like transcription factor family has been determined in the regulation of remarkable processes including cell proliferation, differentiation, signal transduction, oncogenesis, and cell death. A member of this group, Krüppel-like factor 6 (KLF6), identified on the basis of its ability to regulate a group of genes belonging to the carcinoembryonic antigen gene family, has been involved in human carcinogenesis. Early studies proposed a tumor suppressor function for KLF6 because of its ability to reduce cell proliferation through several biochemical mechanisms including regulation of cell cycle components, oncogene products, and apoptosis. Mutations within the klf6 gene, decreased expression and/or loss-of-heterozygosity were associated with the development of different human malignancies, and, hence, further supporting the tumor suppressor function of KLF6. This view has been challenged by other studies in distinct types of human cancers describing infrequent genetic alterations of klf6 gene or even enhanced expression in some tumors. The scenario about KLF6 function became still more complex as the description of oncogenic KLF6 splice variant 1 (SV1) with dominant negative activity against the wild type KLF6 (wtKLF6) protein. Additionally, increased evidence is suggesting that KLF6 is a bonafide target of several signaling cascades, which ultimate regulatory effect on this protein could drive decisions of cell life and death, facing the dilemma about how wtKLF6 could be involved in both processes. These apparently conflicting situations, emerged by apparently opposite effects mediated by wtKLF6, may be related, at least in part, to the biological cross-talk with the c-Jun oncoprotein. Depending on the stimulus received by the cell, wtKLF6 interaction with c-Jun determines different cell outcomes such as proliferation control or apoptosis. Thus, KLF6 responsiveness represents a kind of cell warning signal on receiving different stimuli, including oncogenic activation and microbial infections, orchestrating the implementation of proliferation and apoptotic programs.
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Affiliation(s)
- Verónica Andreoli
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
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Chen H, Chen L, Zhang QF. The Krüppel-like factor 6 genotype is associated with gastric cancer in a Chinese population. J Int Med Res 2011; 38:1801-7. [PMID: 21309496 DOI: 10.1177/147323001003800527] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Association of the IVS1 -27G/A polymorphism of Krüppel-like factor 6 (KLF6) with gastric cancer was examined in a Chinese population comprising 300 gastric cancer patients and 300 healthy controls. Single-nucleotide polymorphism analysis was performed by amplifying intron 1 of KLF6 and sequencing the products. The KLF6 genotype IVS1 -27AA was significantly less frequent in gastric cancer patients than in controls and significantly less frequent in patients with advanced (stage III/IV) gastric cancer than in those with early (stage I/II) cancer. Stratification by location, Lauren's classification and histological differentiation revealed no significant differences in genotype distribution. Thus, in this Chinese population the KLF6 IVS1 -27AA genotype was associated with a decreased risk of gastric cancer and with cancer stage. Further study is required to clarify the mechanisms involved and, potentially, to facilitate the design of effective clinical trials.
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Affiliation(s)
- H Chen
- Department of Urology, Tumour Hospital of Harbin Medical University, Harbin, Heilongjiang Province, China
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Chen CH, Huang PH, Chu PC, Chen MC, Chou CC, Wang D, Kulp SK, Teng CM, Wang Q, Chen CS. Energy restriction-mimetic agents induce apoptosis in prostate cancer cells in part through epigenetic activation of KLF6 tumor suppressor gene expression. J Biol Chem 2011; 286:9968-76. [PMID: 21282102 DOI: 10.1074/jbc.m110.203240] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Although energy restriction has been recognized as an important target for cancer prevention, the mechanism by which energy restriction-mimetic agents (ERMAs) mediate apoptosis remains unclear. By using a novel thiazolidinedione-derived ERMA, CG-12 (Wei, S., Kulp, S. K., and Chen, C. S. (2010) J. Biol. Chem. 285, 9780-9791), vis-à-vis 2-deoxyglucose and glucose deprivation, we obtain evidence that epigenetic activation of the tumor suppressor gene Kruppel-like factor 6 (KLF6) plays a role in ERMA-induced apoptosis in LNCaP prostate cancer cells. KLF6 regulates the expression of many proapoptotic genes, and shRNA-mediated KLF6 knockdown abrogated the ability of ERMAs to induce apoptosis. Chromatin immunoprecipitation analysis indicates that this KLF6 transcriptional activation was associated with increased histone H3 acetylation and histone H3 lysine 4 trimethylation occupancy at the promoter region. Several lines of evidence demonstrate that the enhancing effect of ERMAs on these active histone marks was mediated through transcriptional repression of histone deacetylases and H3 lysine 4 demethylases by down-regulating Sp1 expression. First, putative Sp1-binding elements are present in the promoters of the affected histone-modifying enzymes, and luciferase reporter assays indicate that site-directed mutagenesis of these Sp1 binding sites significantly diminished the promoter activities. Second, shRNA-mediated knockdown of Sp1 mimicked the repressive effect of energy restriction on these histone-modifying enzymes. Third, ectopic Sp1 expression protected cells from the repressive effect of CG-12 on these histone-modifying enzymes, thereby abolishing the activation of KLF6 expression. Together, these findings underscore the intricate relationship between energy restriction and epigenetic regulation of tumor suppressor gene expression, which has therapeutic relevance to foster novel strategies for prostate cancer therapy.
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Affiliation(s)
- Chun-Han Chen
- Division of Medicinal Chemistry, College of Pharmacy, Ohio State University, Columbus, Ohio 43210, USA
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Abstract
The Krüppel-like factor (KLF) family of transcription factors regulates diverse biological processes that include proliferation, differentiation, growth, development, survival, and responses to external stress. Seventeen mammalian KLFs have been identified, and numerous studies have been published that describe their basic biology and contribution to human diseases. KLF proteins have received much attention because of their involvement in the development and homeostasis of numerous organ systems. KLFs are critical regulators of physiological systems that include the cardiovascular, digestive, respiratory, hematological, and immune systems and are involved in disorders such as obesity, cardiovascular disease, cancer, and inflammatory conditions. Furthermore, KLFs play an important role in reprogramming somatic cells into induced pluripotent stem (iPS) cells and maintaining the pluripotent state of embryonic stem cells. As research on KLF proteins progresses, additional KLF functions and associations with disease are likely to be discovered. Here, we review the current knowledge of KLF proteins and describe common attributes of their biochemical and physiological functions and their pathophysiological roles.
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Affiliation(s)
- Beth B McConnell
- Departments of Medicine and of Hematology and Medical Oncology, Emory University School of Medicine,Atlanta, Georgia 30322, USA
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Nucleo-cytoplasmic localization domains regulate Krüppel-like factor 6 (KLF6) protein stability and tumor suppressor function. PLoS One 2010; 5. [PMID: 20844588 PMCID: PMC2936564 DOI: 10.1371/journal.pone.0012639] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Accepted: 08/17/2010] [Indexed: 11/19/2022] Open
Abstract
Background The tumor suppressor KLF6 and its oncogenic cytoplasmic splice variant KLF6-SV1 represent a paradigm in cancer biology in that their antagonistic cancer functions are encoded within the same gene. As a consequence of splicing, KLF6-SV1 loses both the C-terminus C2H2 three zinc finger (ZF) domain, which characterizes all KLF proteins, as well as the adjacent 5′ basic region (5BR), a putative nuclear localization signal (NLS). It has been hypothesized that this NLS is a functional domain critical to direct the distinct subcellular localization of the tumor suppressor and its splice variant. Methodology/Principal Findings In this study, we demonstrate using EGFP fusion constructs that KLF6/KLF6-SV1 nucleo-cytoplasmic transport is not regulated by the 5′ basic region but activated by a novel NLS encoded within the ZF domain, and a nuclear export signal (NES) located in the first 16 amino acids of the shared N-terminus sequence. We demonstrate KLF6 nuclear export to be Crm1-dependent. The dysregulation of nucleo-cytoplasmic transport when disrupting the KLF6 NLS using site-directed mutagenesis showed that its integrity is necessary for appropriate protein stability. Moreover, these mutations impaired transcriptional induction of two KLF6 well-characterized target genes, E-cadherin and p21, as shown by RT-PCR and luciferase promoter assays. The addition of the ZF domain to KLF6-SV1 results in its nuclear localization and a markedly decreased half-life similar to wild type KLF6. Conclusions/Significance We describe the domains that control KLF6 nucleo-cytoplasmic shuttling and how these domains play a role in KLF6 protein half-life and tumor suppressor function. The results begin to mechanistically explain, at least in part, the opposing functions of KLF6 and KLF6-SV1 in cancer.
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Wang S, Kang L, Chen X, Zhou H. Frequent down-regulation and deletion of KLF6 in primary hepatocellular carcinoma. ACTA ACUST UNITED AC 2010; 30:470-6. [PMID: 20714872 DOI: 10.1007/s11596-010-0451-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2009] [Indexed: 12/20/2022]
Abstract
Kruppel-like factor 6 (KLF6) was reported as tumor suppressor in multiple cancers. However, loss of chromosomal locus spanning KLF6 is relatively infrequent in previous published studies. To explore the role of KLF6 in hepatocellular carcinoma (HCC), we examined the gene for expression change, loss of heterozygosity (LOH) and mutation in 26 HCC samples. The expression levels of KLF6 were significantly down-regulated in HCCs, as detected by qRT-PCR. LOH occurred in 11 (52%) of 21 tumors, and all the samples with LOH showed KLF6 down-regulation. The mutational frequency was 24%, and sequence changes located in activation domain of KLF6. Furthermore, MTT assay showed a significant antiproliferative effect of the wt KLF6 transfected in HepG2 hepatoblastoma cells. Fluorescence-activated cell sorting analysis revealed that KLF6 could induce apoptosis. These findings indicate that deregulation of KLF6, together with genetic abnormalities of allelic imbalance and mutations, may play a role in HCC pathogenesis.
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Affiliation(s)
- Shaoping Wang
- Department of Hepatobiliary Surgery, Futian People's Hospital, Shenzhen, 518033, China.
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DiFeo A, Narla G, Martignetti JA. Emerging roles of Kruppel-like factor 6 and Kruppel-like factor 6 splice variant 1 in ovarian cancer progression and treatment. ACTA ACUST UNITED AC 2010; 76:557-66. [PMID: 20014424 DOI: 10.1002/msj.20150] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Epithelial ovarian cancer is one of the most lethal gynecologic cancers and the fifth most frequent cause of female cancer deaths in the United States. Despite dramatic treatment successes in other cancers through the use of molecular agents targeted against genetically defined events driving cancer development and progression, very few insights into epithelial ovarian cancer have been translated from the laboratory to the clinic. If advances are to be made in the early diagnosis, prevention, and treatment of this disease, it will be critical to characterize the common and private (personalized) genetic defects underlying the development and spread of epithelial ovarian cancer. The tumor suppressor Kruppel-like factor 6 and its alternatively spliced, oncogenic isoform, Kruppel-like factor 6 splice variant 1, are members of the Kruppel-like zinc finger transcription factor family of proteins, which have diverse roles in cellular differentiation, development, proliferation, growth-related signal transduction, and apoptosis. Inactivation of Kruppel-like factor 6 and overexpression of Kruppel-like factor 6 splice variant 1 have been associated with the progression of a number of human cancers and even with patient survival. This article summarizes our recent findings demonstrating that a majority of epithelial ovarian cancer tumors have Kruppel-like factor 6 allelic loss and decreased expression coupled with increased expression of Kruppel-like factor 6 splice variant 1. The targeted reduction of Kruppel-like factor 6 in ovarian cancer cell lines results in marked increases in cell proliferation, invasion, tumor growth, angiogenesis, and intraperitoneal dissemination in vivo. In contrast, the inhibition of Kruppel-like factor 6 splice variant 1 decreases cellular proliferation, invasion, angiogenesis, and tumorigenicity; this provides the rationale for its potential therapeutic application. These results and our recent demonstration that the inhibition of Kruppel-like factor 6 splice variant 1 can dramatically prolong survival in a preclinical mouse model of ovarian cancer are reviewed and discussed.
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Gehrau RC, D'Astolfo DS, Dumur CI, Bocco JL, Koritschoner NP. Nuclear expression of KLF6 tumor suppressor factor is highly associated with overexpression of ERBB2 oncoprotein in ductal breast carcinomas. PLoS One 2010; 5:e8929. [PMID: 20126619 PMCID: PMC2812494 DOI: 10.1371/journal.pone.0008929] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Accepted: 01/08/2010] [Indexed: 11/19/2022] Open
Abstract
Background Krüppel-like factor 6 (KLF6) is an evolutionarily conserved and ubiquitously expressed protein that belongs to the mammalian Sp1/KLF family of transcriptional regulators. Though KLF6 is a transcription factor and harbors a nuclear localization signal it is not systematically located in the nucleus but it was detected in the cytoplasm of several tissues and cell lines. Hence, it is still not fully settled whether the tumor suppressor function of KLF6 is directly associated with its ability to regulate target genes. Methodology/Principal Findings In this study we analyzed KLF6 expression and sub-cellular distribution by immunohistochemistry in several normal and tumor tissues in a microarray format representing fifteen human organs. Results indicate that while both nuclear and cytoplasmic distribution of KLF6 is detected in normal breast tissues, breast carcinomas express KLF6 mainly detected in the cytoplasm. Expression of KLF6 was further analyzed in breast cancer tissues overexpressing ERBB2 oncoprotein, which is associated with poor disease prognosis and patient's survival. The analysis of 48 ductal carcinomas revealed a significant population expressing KLF6 predominantly in the nuclear compartment (X2p = 0.005; Fisher p = 0.003). Moreover, this expression pattern correlates directly with early stage and small ductal breast tumors and linked to metastatic events in lymph nodes. Conclusions/Significance Data are consistent with a preferential localization of KLF6 in the nuclear compartment of early stage and small HER2-ERBB2 overexpressing ductal breast tumor cells, also presenting lymph node metastatic events. Thus, KLF6 tumor suppressor could represent a new molecular marker candidate for tumor prognosis and/or a potential target for therapy strategies.
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Affiliation(s)
- Ricardo C. Gehrau
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Diego S. D'Astolfo
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC-CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Catherine I. Dumur
- Department of Pathology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - José L. Bocco
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- * E-mail:
| | - Nicolás P. Koritschoner
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
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Humbert L, Chevrette M. Somatic Molecular Genetics of Prostate Cancer. MALE REPRODUCTIVE CANCERS 2010:143-180. [DOI: 10.1007/978-1-4419-0449-2_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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Zhang Q, Tan XP, Yuan YS, Hu CM, He CH, Wang WZ, Li JC, Zhao Q, Liu NZ. Decreased expression of KLF6 and its significance in gastric carcinoma. Med Oncol 2009; 27:1295-302. [PMID: 19967571 DOI: 10.1007/s12032-009-9377-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2009] [Accepted: 11/23/2009] [Indexed: 10/20/2022]
Abstract
To study the expression of the Krüppel-like transcription factor 6 (KLF6) in human gastric carcinoma and normal gastric mucosa tissues, and to explore the role of KLF6 in the carcinogenesis and tumor progression and its clinical significance. Expression of KLF6, P21WAF1 and PCNA was investigated by immunohistochemistry for 69 surgically resected gastric carcinoma tissues and corresponding normal gastric mucosa tissues, respectively. The correlations of KLF6 expression with clinicopathological characteristics, P21WAF1 and PCNA were examined. Positive-expression of KLF6 was 64 out of 69 cases (92.8%) in normal gastric mucosa and only 23 cases (33.3%) in gastric carcinoma. Expression of KLF6 in the gastric carcinoma was remarkably lower than normal gastric mucosa. Decreased expression of KLF6 in gastric carcinoma was significantly associated with histological differentiation (P<0.01), TNM stage (P<0.05), lymph node metastasis (P<0.01) and distant metastasis (P<0.05). There was no significant correlation between KLF6 expression and sex, age. Meanwhile, expression of KLF6 was associated with expression of P21WAF1 in both normal gastric mucosa and gastric carcinoma (P<0.05). In addition, decreased expression of KLF6 in gastric carcinoma was positively associated with PCNA level (r=0.719, P<0.01) by association analysis. Down-regulation of KLF6 might play an important role in the carcinogenesis and development of human gastric carcinoma and have significant clinical value.
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Affiliation(s)
- Qing Zhang
- Department of Internal Medicine, Clinical Medical College of Yangtze University, and Department of Gastroenterology, No. 1 Hospital Affiliated to Yangtze University, 434000, Jingzhou, Hubei Province, China.
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Liu X, Cheng JC, Turner LS, Elojeimy S, Beckham TH, Bielawska A, Keane TE, Hannun YA, Norris JS. Acid ceramidase upregulation in prostate cancer: role in tumor development and implications for therapy. Expert Opin Ther Targets 2009; 13:1449-58. [PMID: 19874262 PMCID: PMC2796572 DOI: 10.1517/14728220903357512] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Bioactive sphingolipids, such as ceramide, sphingosine and sphingosine-1-phosphate are known bio-effector molecules which play important roles in various aspects of cancer biology including cell proliferation, growth arrest, apoptosis, metastasis, senescence and inflammation. Therefore, enzymes involved in ceramide metabolism are gaining recognition as being critical regulators of cancer cell growth and/or survival. We previously observed that the ceramide metabolizing enzyme, acid ceramidase (AC) is upregulated in tumor tissues. Studies have now concluded that this creates a dysfunctional ceramide pathway, which is responsible for tumor progression and resistance to chemotherapy and radiation. This suggests that development of small-molecule drugs that inhibit AC enzyme activity is a promising approach for improving standard cancer therapy and patient's clinical outcomes.
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Affiliation(s)
- Xiang Liu
- Assistant Professor, Division of Basic Sciences, Departments of: Biochemistry & Molecular Biology, Cell and Molecular Pharmacology & Experimental Therapeutics, Microbiology & Immunology, MUSC, 173 Ashley Avenue, MSC 504, Charleston, South Carolina 29425-5040, FAX: 843.792.4882, Phone: 843.792.7412
| | - Joseph C. Cheng
- MD/PhD Student, Division of Basic Sciences, Departments of: Biochemistry & Molecular Biology, Cell and Molecular Pharmacology & Experimental Therapeutics, Microbiology & Immunology, MUSC, 173 Ashley Avenue, MSC 504, Charleston, South Carolina 29425-5040, FAX: 843.792.4882, Phone: 843.792.8499
| | - Lorianne S. Turner
- Postdoctoral Fellow, Division of Basic Sciences, Departments of: Biochemistry & Molecular Biology, Cell and Molecular Pharmacology & Experimental Therapeutics, Microbiology & Immunology, MUSC, 173 Ashley Avenue, MSC 504, Charleston, South Carolina 29425-5040, FAX: 843.792.4882, Phone: 843.792.8499
| | - Saeed Elojeimy
- Division of Basic Sciences, Departments of: Biochemistry & Molecular Biology, Cell and Molecular Pharmacology & Experimental Therapeutics, Microbiology & Immunology, MUSC, 173 Ashley Avenue, MSC 504, Charleston, South Carolina 29425-5040, FAX: 843.792.4882, Phone: 843.814.7010
| | - Thomas H. Beckham
- MD/PhD Student, Departments of: Biochemistry & Molecular Biology, Cell and Molecular Pharmacology & Experimental Therapeutics, Microbiology & Immunology, MUSC, 173 Ashley Avenue, MSC 504, Charleston, South Carolina 29425-5040, FAX: 843.792.4882, Phone: 843.792.8499
| | - Alicja Bielawska
- Professor, Departments of: Biochemistry & Molecular Biology, Cell and Molecular Pharmacology & Experimental Therapeutics, Microbiology & Immunology, MUSC, 173 Ashley Avenue, MSC 504, Charleston, South Carolina 29425-5040, FAX: 843.792.1627, Phone: 843.792.0273
| | - Thomas E. Keane
- Professor and Chair, Department of Urology, MUSC, 96 Jonathan Lucas Street, Room 644, Clinical Science Building, Phone: 843.792.1666
| | - Yusuf A. Hannun
- Senior Associate Dean for Basic Sciences, Director, Division of Basic Sciences, Distinguished University Professor, Chair, Department of Biochemistry & Molecular Biology, Cell and Molecular Pharmacology & Experimental Therapeutics, Microbiology & Immunology, MUSC, 173 Ashley Avenue, MSC 509, Charleston, South Carolina 29425-5090, FAX: 843.792.4322, Phone: 843.792.9318
| | - James S. Norris
- Professor and Chair, Department of Microbiology & Immunology, MUSC, 173 Ashley Avenue, MSC 504, Charleston, South Carolina 29425-5040, FAX: 843.792.4882, Phone: 843.792.7915
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Liu J, Du T, Yuan Y, He Y, Tan Z, Liu Z. KLF6 inhibits estrogen receptor-mediated cell growth in breast cancer via a c-Src-mediated pathway. Mol Cell Biochem 2009; 335:29-35. [PMID: 19707857 DOI: 10.1007/s11010-009-0237-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2009] [Accepted: 08/13/2009] [Indexed: 11/25/2022]
Abstract
Estrogen receptors play a key role in breast cancer development and progression. Kruppel-like factor 6 (KLF6) is a tumour-suppressing protein. The aim of this study was to identify the role of KLF6 inhibition in estrogen receptor(alpha) (ERalpha)-elicited breast cancer development. Protein expression levels were examined by western blot analysis and immunoprecipitation was used to analyse interactions between proteins. An MTT assay was used to study cell proliferation. We found that KLF6 mediates cell growth in ERalpha-positive breast cancer cells through interaction with the c-Src protein. This interaction causes inactivation of the Erk and Akt proteins. These pathways are critical for the proliferation and survival of breast cancer cells. We also established that KLF6 could not mediate cell growth in ERalpha-negative cells. We conclude that KLF6 can modulate ERalpha-mediated cell growth in breast cancer cells. The unique role of KLF6 in mediating cell growth in breast cancer cells opens up the possibility of a new therapeutic strategy for treating breast cancer.
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Affiliation(s)
- Jun Liu
- Department of General Surgery, Zhongnan Hospital of Wuhan University, 169 Donghu Road, Wuhan 430071, China
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46
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Dong JT, Chen C. Essential role of KLF5 transcription factor in cell proliferation and differentiation and its implications for human diseases. Cell Mol Life Sci 2009; 66:2691-706. [PMID: 19448973 PMCID: PMC11115749 DOI: 10.1007/s00018-009-0045-z] [Citation(s) in RCA: 208] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2009] [Revised: 04/22/2009] [Accepted: 04/24/2009] [Indexed: 02/08/2023]
Abstract
KLF5 (Kruppel-like factor 5) is a basic transcription factor binding to GC boxes at a number of gene promoters and regulating their transcription. KLF5 is expressed during development and, in adults, with higher levels in proliferating epithelial cells. The expression and activity of KLF5 are regulated by multiple signaling pathways, including Ras/MAPK, PKC, and TGFbeta, and various posttranslational modifications, including phosphorylation, acetylation, ubiquitination, and sumoylation. Consistently, KLF5 mediates the signaling functions in cell proliferation, cell cycle, apoptosis, migration, differentiation, and stemness by regulating gene expression in response to environment stimuli. The expression of KLF5 is frequently abnormal in human cancers and in cardiovascular disease-associated vascular smooth muscle cells (VSMCs). Due to its significant functions in cell proliferation, survival, and differentiation, KLF5 could be a potential diagnostic biomarker and therapeutic target for cancer and cardiovascular diseases.
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Affiliation(s)
- Jin-Tang Dong
- Department of Hematology and Medical Oncology, Department of Urology and Winship Cancer Institute, Emory University School of Medicine, 1365-C Clifton Road, Atlanta, GA 30322, USA.
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Abstract
One of the main engines that drives cellular transformation is the loss of proper control of the mammalian cell cycle. The cyclin-dependent kinase inhibitor p21 (also known as p21WAF1/Cip1) promotes cell cycle arrest in response to many stimuli. It is well positioned to function as both a sensor and an effector of multiple anti-proliferative signals. This Review focuses on recent advances in our understanding of the regulation of p21 and its biological functions with emphasis on its p53-independent tumour suppressor activities and paradoxical tumour-promoting activities, and their implications in cancer.
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Affiliation(s)
- Tarek Abbas
- Department of Biochemistry and Molecular Genetics, University of Virginia, School of Medicine, 1340 Jefferson Park Avenue, Charlottesville, VA 22908, USA.
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48
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Frigo DE, Sherk AB, Wittmann BM, Norris JD, Wang Q, Joseph JD, Toner AP, Brown M, McDonnell DP. Induction of Kruppel-like factor 5 expression by androgens results in increased CXCR4-dependent migration of prostate cancer cells in vitro. Mol Endocrinol 2009; 23:1385-96. [PMID: 19460858 DOI: 10.1210/me.2009-0010] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Advanced prostate cancers preferentially metastasize to bone, suggesting that this tissue produces factors that provide a suitable microenvironment for prostate cancer cells. Recently, it has become clear that even in antiandrogen-resistant cancers, the androgen receptor (AR)-signaling axis is required for prostate cancer progression. Therefore, we hypothesized that AR may be involved in the regulation of pathways that are responsible for the homing of prostate cancer cells to select microenvironments. In support of this hypothesis, we have determined that chemokine (C-X-C motif) receptor 4 (CXCR4), the receptor for the chemokine CXCL12, is up-regulated in prostate cancer cells in response to androgens. Given that the levels of CXCL12 are elevated at sites of known prostate cancer metastases such as bone, these results suggest that androgens may influence prostate cancer metastasis. Specifically, we demonstrate that androgens increase the levels of both CXCR4 mRNA and functional protein in LNCaP prostate cancer cells. Importantly, androgens enhanced the migration of LNCaP cells toward a CXCL12 gradient, an effect that could be blocked by the specific CXCR4 antagonist AMD3100. Interestingly, CXCR4 is not directly regulated by androgens but rather is positively up-regulated by Krüppel-like factor 5 (KLF5), a transcription factor that we have shown to be an early, direct target of AR. Further, KLF5 is both required and sufficient for androgen-mediated CXCR4 expression and migration toward CXCL12. Taken together, these findings demonstrate that AR can utilize the CXCL12/CXCR4 axis through induction of KLF5 expression to promote prostate cancer progression and highlight the potential utility of CXCR4 antagonists as prostate cancer therapeutics.
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Affiliation(s)
- Daniel E Frigo
- Duke University Medical Center, Department of Pharmacology, Box 3813, Durham, North Carolina 27710, USA
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TGF-beta regulates the expression of transcription factor KLF6 and its splice variants and promotes co-operative transactivation of common target genes through a Smad3-Sp1-KLF6 interaction. Biochem J 2009; 419:485-95. [PMID: 19076057 DOI: 10.1042/bj20081434] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
KLF6 (Krüppel-like factor 6) is a transcription factor and tumour suppressor with a growing range of biological activities and transcriptional targets. Among these, KLF6 suppresses growth through transactivation of TGF-beta1 (transforming growth factor-beta1). KLF6 can be alternatively spliced, generating lower-molecular-mass isoforms that antagonize the full-length WT (wild-type) protein and promote growth. A key target gene of full-length KLF6 is endoglin, which is induced in vascular injury. Endoglin, a homodimeric cell membrane glycoprotein and TGF-beta auxiliary receptor, has a pro-angiogenic role in endothelial cells and is also involved in malignant progression. The aim of the present work was to explore the effect of TGF-beta on KLF6 expression and splicing, and to define the contribution of TGF-beta on promoters regulated by co-operation between KLF6 and Sp1 (specificity protein 1). Using co-transfection, co-immunoprecipitation and fluorescence resonance energy transfer, our data demonstrate that KLF6 co-operates with Sp1 in transcriptionally regulating KLF6-responsive genes and that this co-operation is further enhanced by TGF-beta1 through at least two mechanisms. First, in specific cell types, TGF-beta1 may decrease KLF6 alternative splicing, resulting in a net increase in full-length, growth-suppressive KLF6 activity. Secondly, KLF6-Sp1 co-operation is further enhanced by the TGF-beta-Smad (similar to mothers against decapentaplegic) pathway via the likely formation of a tripartite KLF6-Sp1-Smad3 complex in which KLF6 interacts indirectly with Smad3 through Sp1, which may serve as a bridging molecule to co-ordinate this interaction. These findings unveil a finely tuned network of interactions between KLF6, Sp1 and TGF-beta to regulate target genes.
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Sangodkar J, Shi J, DiFeo A, Schwartz R, Bromberg R, Choudhri A, McClinch K, Hatami R, Scheer E, Kremer-Tal S, Martignetti JA, Hui A, Leung WK, Friedman SL, Narla G. Functional role of the KLF6 tumour suppressor gene in gastric cancer. Eur J Cancer 2008; 45:666-76. [PMID: 19101139 DOI: 10.1016/j.ejca.2008.11.009] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2008] [Revised: 10/31/2008] [Accepted: 11/05/2008] [Indexed: 11/17/2022]
Abstract
Gastric cancer is the second most common cancer and a leading cause of cancer-related death worldwide. The Kruppel-like factor 6 (KLF6) tumour suppressor gene had been previously shown to be inactivated in a number of human cancers through loss of heterozygosity (LOH), somatic mutation, decreased expression and increased alternative splicing into a dominant negative oncogenic splice variant, KLF6-SV1. In the present study, 37 gastric cancer samples were analysed for the presence of loss of heterozygosity (LOH) of the KLF6 locus and somatic mutation. In total, 18 of 34 (53%) of the gastric cancer samples analysed demonstrated KLF6 locus specific loss. Four missense mutations, such as T179I, R198G, R71Q and S180L, were detected. Interestingly, two of these mutations R71Q and S180L have been identified independently by several groups in various malignancies including prostate, colorectal and gastric cancers. In addition, decreased wild-type KLF6 (wtKLF6) expression was associated with loss of the KLF6 locus and was present in 48% of primary gastric tumour samples analysed. Functional studies confirmed that wtKLF6 suppressed proliferation of gastric cancer cells via transcriptional regulation of the cyclin-dependent kinase inhibitor p21 and the oncogene c-myc. Functional characterisation of the common tumour-derived mutants demonstrated that the mutant proteins fail to suppress proliferation and function as dominant negative regulators of wtKLF6 function. Furthermore, stable overexpression of the R71Q and S180L tumour-derived mutants in the gastric cancer cell line, Hs746T, resulted in an increased tumourigenicity in vivo. Combined, these findings suggest an important role for the KLF6 tumour suppressor gene in gastric cancer development and progression and identify several highly cancer-relevant signalling pathways regulated by the KLF6 tumour suppressor gene.
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Affiliation(s)
- Jaya Sangodkar
- Department of Medicine, Mount Sinai School of Medicine, New York, NY, United States
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