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Hussein OA, Labib HA, Haggag R, Hamed Sakr MM. Phe354Leu polymorphism of the liver kinase B1 gene as a prognostic factor in adult egyptian patients with acute myeloid leukemia. Heliyon 2023; 9:e15415. [PMID: 37215763 PMCID: PMC10192405 DOI: 10.1016/j.heliyon.2023.e15415] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 03/30/2023] [Accepted: 04/06/2023] [Indexed: 05/24/2023] Open
Abstract
Background The human liver kinase B1 (LKB1) gene is a significant tumor suppressor widely expressed in all fetal and adult tissues. Despite its established role in solid tumors, the biological and clinical implications of LKB1 gene alterations in hematological malignancies have not been sufficiently recognized. Aim This study aimed to determine the frequency of the LKB1 Phe354Leu polymorphism in adult Egyptian patients with cytogenetically normal AML (CN-AML), evaluate its clinical prognostic significance, and investigate its effect on the therapeutic outcome and patient survival. Methods Direct sequencing of amplified exon eight of the LKB1 gene was performed to detect the Phe354Leu polymorphism in 72 adult de novo CN-AML patients. Results The LKB1 Phe354Leu polymorphism was detected in 16.7% of patients and associated with younger age and lower hemoglobin levels (p < 0.001). Patients in the mutated group had significantly higher total leukocytic count and bone marrow blasts (p = 0.001 and p < 0.001, respectively). The most common FAB subtypes in mutated patients were M4 and M2. The relapse rate was significantly higher in the mutated group (p = 0.004). There was a significant association between the FLT3-ITD polymorphism and LKB1 F354L (p < 0.001). The mutated group had shorter overall survival (p = 0.003). In multivariate analysis, the Phe354Leu polymorphism was a significant independent prognostic variable for the overall and disease-free survival of the studied patients (p = 0.049). Conclusion The LKB1 Phe354Leu polymorphism was diagnosed at younger ages in Egyptian CN-AML patients and represented a poor independent prognostic factor in CN-AML. Patients who carried this polymorphism had shorter overall survival and more frequent relapses. Our findings may provide insight into the design of therapeutic targets, and molecular testing of the LKB1 gene is recommended for proper risk stratification of CN-AML patients.
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Affiliation(s)
- Ola A. Hussein
- Department of Clinical Pathology, Faculty of Medicine, Zagazig University, Egypt
| | - Hany A. Labib
- Department of Clinical Pathology, Faculty of Medicine, Zagazig University, Egypt
| | - Rasha Haggag
- Department of Medical Oncology, Faculty of Medicine, Zagazig University, Egypt
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Song Y, Zhao F, Ma W, Li G. Hotspots and trends in liver kinase B1 research: A bibliometric analysis. PLoS One 2021; 16:e0259240. [PMID: 34735498 PMCID: PMC8568265 DOI: 10.1371/journal.pone.0259240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 10/15/2021] [Indexed: 11/29/2022] Open
Abstract
Introduction In the past 22 years, a large number of publications have reported that liver kinase B1 (LKB1) can regulate a variety of cellular processes and play an important role in many diseases. However, there is no systematic bibliometric analysis on the publications of LKB1 to reveal the research hotspots and future direction. Methods Publications were retrieved from the Web of Science Core Collection (WoSCC), Scopus, and PubMed databases. CiteSpace and VOSviewer were used to analysis the top countries, institutions, authors, source journals, discipline categories, references, and keywords. Results In the past 22 years, the number of LKB1 publications has increased gradually by year. The country, institution, author, journals that have published the most articles and cited the most frequently were the United States, Harvard University, Prof. Benoit Viollet, Journal of Biochemistry and Plos One. The focused research hotspot was the molecular functions of LKB1. The emerging hotspots and future trends are the clinical studies about LKB1 and co-mutated genes as biomarkers in tumors, especially in lung adenocarcinoma. Conclusions Our research could provide knowledge base, frontiers, emerging hotspots and future trends associated with LKB1 for researchers in this field, and contribute to finding potential cooperation possibilities.
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Affiliation(s)
- Yaowen Song
- Department of Radiotherapy Oncology, The First Affiliated Hospital of China Medical University, Shenyan, China
| | - Fangkun Zhao
- Department of Ophthalmology, The Fourth Affiliated Hospital of China Medical University, Shenyang, China
| | - Wei Ma
- Department of Breast Surgery, The First Affiliated Hospital of China Medical University, Shenyang, China
| | - Guang Li
- Department of Radiotherapy Oncology, The First Affiliated Hospital of China Medical University, Shenyan, China
- * E-mail:
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Figueroa-González G, Carrillo-Hernández JF, Perez-Rodriguez I, Cantú de León D, Campos-Parra AD, Martínez-Gutiérrez AD, Coronel-Hernández J, García-Castillo V, López-Camarillo C, Peralta-Zaragoza O, Jacobo-Herrera NJ, Guardado-Estrada M, Pérez-Plasencia C. Negative Regulation of Serine Threonine Kinase 11 (STK11) through miR-100 in Head and Neck Cancer. Genes (Basel) 2020; 11:E1058. [PMID: 32911741 PMCID: PMC7563199 DOI: 10.3390/genes11091058] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 08/18/2020] [Accepted: 08/25/2020] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Serine Threonine Kinase 11 (STK11), also known as LKB1, is a tumor suppressor gene that regulates several biological processes such as apoptosis, energetic metabolism, proliferation, invasion, and migration. During malignant progression, different types of cancer inhibit STK11 function by mutation or epigenetic inactivation. In Head and Neck Cancer, it is unclear what mechanism is involved in decreasing STK11 levels. Thus, the present work aims to determine whether STK11 expression might be regulated through epigenetic or post-translational mechanisms. METHODS Expression levels and methylation status for STK11 were analyzed in 59 cases of head and neck cancer and 10 healthy tissue counterparts. Afterward, we sought to identify candidate miRNAs exerting post-transcriptional regulation of STK11. Then, we assessed a luciferase gene reporter assay to know if miRNAs directly target STK11 mRNA. The expression levels of the clinical significance of mir-100-3p, -5p, and STK11 in 495 HNC specimens obtained from the TCGA database were further analyzed. Finally, the Kaplan-Meier method was used to estimate the prognostic significance of the miRNAs for Overall Survival, and survival curves were compared through the log-rank test. RESULTS STK11 was under-expressed, and its promoter region was demethylated or partially methylated. miR-17-5p, miR-106a-5p, miR-100-3p, and miR-100-5p could be negative regulators of STK11. Our experimental data suggested evidence that miR-100-3p and -5p were over-expressed in analyzed tumor patient samples. Luciferase gene reporter assay experiments showed that miR-100-3p targets and down-regulates STK11 mRNA directly. With respect to overall survival, STK11 expression level was significant for predicting clinical outcomes. CONCLUSION This is, to our knowledge, the first report of miR-100-3p targeting STK11 in HNC. Together, these findings may support the importance of regulation of STK11 through post-transcriptional regulation in HNC and the possible contribution to the carcinogenesis process in this neoplasia.
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Affiliation(s)
- Gabriela Figueroa-González
- Unidad Multidisciplinaria de Investigación Experimental Zaragoza (UMIEZ), Facultad de Estudios Superiores Zaragoza, Universidad Nacional Autónoma de México, Mexico City 09230, Mexico;
- Unidad de Investigación Biomédica en Cáncer, Laboratorio de Genómica, Instituto Nacional de Cancerología, Mexico City 14080, Mexico; (J.F.C.-H.); (I.P.-R.); (D.C.d.L.); (A.D.C.-P.); (A.D.M.-G.); (J.C.-H.)
| | - José F. Carrillo-Hernández
- Unidad de Investigación Biomédica en Cáncer, Laboratorio de Genómica, Instituto Nacional de Cancerología, Mexico City 14080, Mexico; (J.F.C.-H.); (I.P.-R.); (D.C.d.L.); (A.D.C.-P.); (A.D.M.-G.); (J.C.-H.)
| | - Itzel Perez-Rodriguez
- Unidad de Investigación Biomédica en Cáncer, Laboratorio de Genómica, Instituto Nacional de Cancerología, Mexico City 14080, Mexico; (J.F.C.-H.); (I.P.-R.); (D.C.d.L.); (A.D.C.-P.); (A.D.M.-G.); (J.C.-H.)
| | - David Cantú de León
- Unidad de Investigación Biomédica en Cáncer, Laboratorio de Genómica, Instituto Nacional de Cancerología, Mexico City 14080, Mexico; (J.F.C.-H.); (I.P.-R.); (D.C.d.L.); (A.D.C.-P.); (A.D.M.-G.); (J.C.-H.)
| | - Alma D. Campos-Parra
- Unidad de Investigación Biomédica en Cáncer, Laboratorio de Genómica, Instituto Nacional de Cancerología, Mexico City 14080, Mexico; (J.F.C.-H.); (I.P.-R.); (D.C.d.L.); (A.D.C.-P.); (A.D.M.-G.); (J.C.-H.)
| | - Antonio D. Martínez-Gutiérrez
- Unidad de Investigación Biomédica en Cáncer, Laboratorio de Genómica, Instituto Nacional de Cancerología, Mexico City 14080, Mexico; (J.F.C.-H.); (I.P.-R.); (D.C.d.L.); (A.D.C.-P.); (A.D.M.-G.); (J.C.-H.)
| | - Jossimar Coronel-Hernández
- Unidad de Investigación Biomédica en Cáncer, Laboratorio de Genómica, Instituto Nacional de Cancerología, Mexico City 14080, Mexico; (J.F.C.-H.); (I.P.-R.); (D.C.d.L.); (A.D.C.-P.); (A.D.M.-G.); (J.C.-H.)
| | - Verónica García-Castillo
- Unidad de Investigación Biomédica en Cáncer, Laboratorio de Genómica del Cáncer, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Tlalnepantla 54090, Edo.Mex, Mexico;
| | - César López-Camarillo
- Posgrado en Ciencias Genómicas, Universidad Autónoma de la Ciudad de México, Mexico City 09790, Mexico;
| | - Oscar Peralta-Zaragoza
- Dirección de Infecciones Crónicas y Cáncer, Centro de Investigación Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca 62100, Morelos, Mexico;
| | - Nadia J. Jacobo-Herrera
- Unidad de Bioquímica, Instituto Nacional de Nutrición y Ciencias Médicas, Salvador Zubirán, Mexico City 14000, Mexico;
| | - Mariano Guardado-Estrada
- Laboratorio de Genética, Licenciatura en Ciencia Forense, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City 04360, Mexico;
| | - Carlos Pérez-Plasencia
- Unidad de Investigación Biomédica en Cáncer, Laboratorio de Genómica, Instituto Nacional de Cancerología, Mexico City 14080, Mexico; (J.F.C.-H.); (I.P.-R.); (D.C.d.L.); (A.D.C.-P.); (A.D.M.-G.); (J.C.-H.)
- Unidad de Investigación Biomédica en Cáncer, Laboratorio de Genómica del Cáncer, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Tlalnepantla 54090, Edo.Mex, Mexico;
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Sfakianaki M, Papadaki C, Tzardi M, Trypaki M, Alam S, Lagoudaki ED, Messaritakis I, Zoras O, Mavroudis D, Georgoulias V, Souglakos J. Loss of LKB1 Protein Expression Correlates with Increased Risk of Recurrence and Death in Patients with Resected, Stage II or III Colon Cancer. Cancer Res Treat 2019; 51:1518-1526. [PMID: 30913862 PMCID: PMC6790836 DOI: 10.4143/crt.2019.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 03/17/2019] [Indexed: 02/06/2023] Open
Abstract
PURPOSE The purpose of this study was to investigate the prognostic significance of liver kinase b1 (LKB1) loss in patients with operable colon cancer (CC). Materials and Methods Two hundred sixty-two specimens from consecutive patients with stage III or high-risk stage II CC, who underwent surgical resection with curative intent and received adjuvant chemotherapy with fluoropyrimidine and oxaliplatin, were analyzed for LKB1 protein expression loss, by immunohistochemistry as well as for KRAS exon 2 and BRAFV600E mutations by Sanger sequencing and TS, ERCC1, MYC, and NEDD9 mRNA expression by real-time quantitative reverse transcription polymerase chain reaction. RESULTS LKB1 expression loss was observed in 117 patients (44.7%) patients and correlated with right-sided located primaries (p=0.032), and pericolic lymph nodes involvement (p=0.003), BRAFV600E mutations (p=0.024), and TS mRNA expression (p=0.041). Patients with LKB1 expression loss experienced significantly lower disease-free survival (DFS) (hazard ratio [HR], 1.287; 95% confidence interval [CI], 1.093 to 1.654; p=0.021) and overall survival (OS) (HR, 1.541; 95% CI, 1.197 to 1.932; p=0.002), compared to patients with LKB1 expressing expressing tumors. Multivariate analysis revealed LKB1 expression loss as independent prognostic factor for both decreased DFS (HR, 1.217; 95% CI, 1.074 to 1.812; p=0.034) and decreased OS (HR, 1.467; 95% CI, 1.226 to 2.122; p=0.019). CONCLUSION Loss of tumoral LKB1 protein expression, constitutes an adverse prognostic factor in patients with operable CC.
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Affiliation(s)
- Maria Sfakianaki
- Laboratory of Translational Oncology, School of Medicine, University of Crete, Heraklion, Greece
| | - Chara Papadaki
- Laboratory of Translational Oncology, School of Medicine, University of Crete, Heraklion, Greece
| | - Maria Tzardi
- Department of Pathology, University General Hospital of Heraklion, Iraklio, Greece
| | - Maria Trypaki
- Laboratory of Translational Oncology, School of Medicine, University of Crete, Heraklion, Greece
| | - Sardar Alam
- Laboratory of Translational Oncology, School of Medicine, University of Crete, Heraklion, Greece
| | - Eleni D Lagoudaki
- Laboratory of Translational Oncology, School of Medicine, University of Crete, Heraklion, Greece
| | - Ippokratis Messaritakis
- Laboratory of Translational Oncology, School of Medicine, University of Crete, Heraklion, Greece
| | - Odysseas Zoras
- Department of Surgical Oncology, University General Hospital of Heraklion, Iraklio, Greece
| | - Dimitris Mavroudis
- Laboratory of Translational Oncology, School of Medicine, University of Crete, Heraklion, Greece.,Department of Medical Oncology, University General Hospital of Heraklion, Iraklio, Greece
| | | | - John Souglakos
- Laboratory of Translational Oncology, School of Medicine, University of Crete, Heraklion, Greece.,Department of Medical Oncology, University General Hospital of Heraklion, Iraklio, Greece
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5
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Yang MY, Hsiao HH, Liu YC, Hsu CM, Lin SF, Lin PM. Phe354Leu Polymorphism of LKB1 Is a Potential Prognostic Factor for Cytogenetically Normal Acute Myeloid Leukemia. ACTA ACUST UNITED AC 2017; 31:841-847. [PMID: 28882949 DOI: 10.21873/invivo.11137] [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: 07/15/2017] [Revised: 07/28/2017] [Accepted: 08/02/2017] [Indexed: 11/10/2022]
Abstract
BACKGROUND/AIM Liver kinase B1 (LKB1) is a major activator of the AMP-dependent kinase/mammalian target of rapamycin pathway. The prevalence and the specificity of LKB1 gene mutation in acute myeloid leukemia (AML) have not been well established. This study aimed to examine mutation of LKB1 in AML and its clinical and pathological implications. PATIENTS AND METHODS Eighty-five patients newly diagnosed with cytogenetically normal AML were analyzed using polymerase chain reaction followed by direct sequencing. RESULTS A silent mutation (837C>T) of LKB1 was detected in one patient and a pathogenic polymorphism Phe354Leu which diminishes LKB1 ability to maintain cell polarity was detected in six (7%) patients. The Phe354Leu polymorphism occurred concurrently with mutations of nucleophosmin 1 (NPM1), fms-related tyrosine kinase 3 (FLT3) and CCAAT/enhancer binding protein alpha (CEBPA), but not with metabolism-related genes, isocitrate dehydrogenase [nicotinamide adenine dinucleotide phosphate (+)]1 (IDH1) and IDH2. Patients with Phe354Leu polymorphism diagnosed at younger ages had a worse overall survival. CONCLUSION LKB1 may be involved in the leukemogenesis and progression of cytogenetically normal AML.
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Affiliation(s)
- Ming-Yu Yang
- Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan, R.O.C.,Departments of Otolaryngology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan, R.O.C
| | - Hui-Hua Hsiao
- Division of Hematology-Oncology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan, R.O.C.,Faculty of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan, R.O.C
| | - Yi-Chang Liu
- Division of Hematology-Oncology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan, R.O.C.,Faculty of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan, R.O.C
| | - Cheng-Ming Hsu
- Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan, R.O.C. .,Department of Otolaryngology, Chiayi Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Chiayi, Taiwan, R.O.C
| | - Sheng-Fung Lin
- Division of Hematology-Oncology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan, R.O.C. .,Faculty of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan, R.O.C
| | - Pai-Mei Lin
- Department of Nursing, I-Shou University, Kaohsiung, Taiwan, R.O.C.
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Cidlinsky N, Dogliotti G, Pukrop T, Jung R, Weber F, Krahn MP. Inactivation of the LKB1-AMPK signaling pathway does not contribute to salivary gland tumor development - a short report. Cell Oncol (Dordr) 2016; 39:389-96. [PMID: 27480082 DOI: 10.1007/s13402-016-0290-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/15/2016] [Indexed: 01/05/2023] Open
Abstract
PURPOSE Activation of AMPK by the tumor suppressor LKB1 represents an essential gatekeeping step for cells under energetic stress to prevent their growth and proliferation by inhibiting mTOR activation, until the energy supply normalizes. The LKB1/AMPK pathway is frequently downregulated in various types of cancer, thereby uncoupling tumor cell growth and proliferation from energy supply. As yet, little information is available on the role of the LKB1/AMPK pathway in tumors derived from salivary gland tissues. METHODS We performed LKB1 protein expression and AMPK and mTOR activation analyses in several salivary gland tumor types and their respective healthy control tissues using immunohistochemistry. RESULTS No significant downregulation of LKB1 expression or decreased activation of AMPK or mTOR were observed in any of the salivary gland tumors tested. In contrast, we found that the salivary gland tumors exhibited an increased rather than a decreased AMPK activation. Although the PI3K/Akt pathway was found to be activated in most of the analyzed tumor samples, the unchanged robust activity of LKB1/AMPK likely prevents (over)activation of mTOR. CONCLUSION In contrast to many other types of cancer, inactivation or downregulation of the LKB1/AMPK pathway does not substantially contribute to the pathogenesis of salivary gland tumors.
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Affiliation(s)
- Natascha Cidlinsky
- Molecular and Cellular Anatomy, University of Regensburg, Universitätsstr. 31, 93053, Regensburg, Germany
| | - Giada Dogliotti
- Molecular and Cellular Anatomy, University of Regensburg, Universitätsstr. 31, 93053, Regensburg, Germany
| | - Tobias Pukrop
- Department of Internal Medicine III, Hematology and Medical Oncology, University Hospital Regensburg, Franz-Josef-Strauss-Allee 11, 93053, Regensburg, Germany
| | - Rudolf Jung
- Institute for Pathology, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93053, Regensburg, Germany
| | - Florian Weber
- Institute for Pathology, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93053, Regensburg, Germany
| | - Michael P Krahn
- Molecular and Cellular Anatomy, University of Regensburg, Universitätsstr. 31, 93053, Regensburg, Germany.
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7
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Li Z, Wang C, Zhu J, Bai Y, Wang W, Zhou Y, Zhang S, Liu X, Zhou S, Huang W, Bi Y, Wang H. The possible role of liver kinase B1 in hydroquinone-induced toxicity of murine fetal liver and bone marrow hematopoietic stem cells. ENVIRONMENTAL TOXICOLOGY 2016; 31:830-841. [PMID: 25534963 DOI: 10.1002/tox.22094] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 12/02/2014] [Accepted: 12/07/2014] [Indexed: 06/04/2023]
Abstract
Epidemiological studies suggest that the increasing incidence of childhood leukemia may be due to maternal exposure to benzene, which is a known human carcinogen; however, the mechanisms involved remain unknown. Liver Kinase B1 (LKB1) acts as a regulator of cellular energy metabolism and functions to regulate hematopoietic stem cell (HSC) homeostasis. We hypothesize that LKB1 contributes to the deregulation of fetal or bone hematopoiesis caused by the benzene metabolite hydroquinone (HQ). To evaluate this hypothesis, we compared the effects of HQ on murine fetal liver hematopoietic stem cells (FL-HSCs) and bone marrow hematopoietic stem cells (BM-HSCs). FL-HSCs and BM-HSCs were isolated and enriched by a magnetic cell sorting system and exposed to various concentrations of HQ (0, 1.25, 2.5, 5, 10, 20, and 40 μM) for 24 h. We found that the inhibition of differentiation and growth, as well as the apoptosis rate of FL-HSCs, induced by HQ were consistent with the changes in BM-HSCs. Furthermore, G1 cell cycle arrest was observed in BM-HSCs and FL-HSCs in response to HQ. Importantly, FL-HSCs were more sensitive than BM-HSCs after exposure to HQ. The highest induction of LKB1 and adenosine monophosphate-activated protein kinase (AMPK) was observed with a much lower concentration of HQ in FL-HSCs than in BM-HSCs. LKB1 may play a critical role in apoptosis and cell cycle arrest of HQ-treated HSCs. This research has developed innovative ideas concerning benzene-induced hematopoietic toxicity or embryotoxicity, which can provide a new experimental evidence for preventing childhood leukemia. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 830-841, 2016.
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Affiliation(s)
- Zhen Li
- Department of Occupational and Environmental Health, School of Public Health, Wuhan University, Wuhan, Hubei, People's Republic of China
- Hubei Key Laboratory of Allergy and Immune-Related Diseases, Wuhan, Hubei, People's Republic of China
- Hubei Biomass-Resource Chemistry and Environmental Biotechnology Key Laboratory, Wuhan University, Wuhan, Hubei, People's Republic of China
| | - Chunhong Wang
- Department of Occupational and Environmental Health, School of Public Health, Wuhan University, Wuhan, Hubei, People's Republic of China
- Hubei Key Laboratory of Allergy and Immune-Related Diseases, Wuhan, Hubei, People's Republic of China
- Hubei Biomass-Resource Chemistry and Environmental Biotechnology Key Laboratory, Wuhan University, Wuhan, Hubei, People's Republic of China
| | - Jie Zhu
- Department of Occupational and Environmental Health, School of Public Health, Wuhan University, Wuhan, Hubei, People's Republic of China
- Hubei Key Laboratory of Allergy and Immune-Related Diseases, Wuhan, Hubei, People's Republic of China
- Hubei Biomass-Resource Chemistry and Environmental Biotechnology Key Laboratory, Wuhan University, Wuhan, Hubei, People's Republic of China
| | - YuE Bai
- Department of Occupational and Environmental Health, School of Public Health, Wuhan University, Wuhan, Hubei, People's Republic of China
- Hubei Key Laboratory of Allergy and Immune-Related Diseases, Wuhan, Hubei, People's Republic of China
- Hubei Biomass-Resource Chemistry and Environmental Biotechnology Key Laboratory, Wuhan University, Wuhan, Hubei, People's Republic of China
| | - Wei Wang
- Department of Occupational and Environmental Health, School of Public Health, Wuhan University, Wuhan, Hubei, People's Republic of China
- Hubei Key Laboratory of Allergy and Immune-Related Diseases, Wuhan, Hubei, People's Republic of China
- Hubei Biomass-Resource Chemistry and Environmental Biotechnology Key Laboratory, Wuhan University, Wuhan, Hubei, People's Republic of China
| | - Yanfeng Zhou
- Department of Occupational and Environmental Health, School of Public Health, Wuhan University, Wuhan, Hubei, People's Republic of China
- Hubei Key Laboratory of Allergy and Immune-Related Diseases, Wuhan, Hubei, People's Republic of China
- Hubei Biomass-Resource Chemistry and Environmental Biotechnology Key Laboratory, Wuhan University, Wuhan, Hubei, People's Republic of China
| | - Shaozun Zhang
- Department of Occupational and Environmental Health, School of Public Health, Wuhan University, Wuhan, Hubei, People's Republic of China
- Hubei Key Laboratory of Allergy and Immune-Related Diseases, Wuhan, Hubei, People's Republic of China
- Hubei Biomass-Resource Chemistry and Environmental Biotechnology Key Laboratory, Wuhan University, Wuhan, Hubei, People's Republic of China
| | - Xiangxiang Liu
- Department of Occupational and Environmental Health, School of Public Health, Wuhan University, Wuhan, Hubei, People's Republic of China
- Hubei Key Laboratory of Allergy and Immune-Related Diseases, Wuhan, Hubei, People's Republic of China
- Hubei Biomass-Resource Chemistry and Environmental Biotechnology Key Laboratory, Wuhan University, Wuhan, Hubei, People's Republic of China
| | - Sheng Zhou
- Department of Occupational and Environmental Health, School of Public Health, Wuhan University, Wuhan, Hubei, People's Republic of China
- Hubei Key Laboratory of Allergy and Immune-Related Diseases, Wuhan, Hubei, People's Republic of China
- Hubei Biomass-Resource Chemistry and Environmental Biotechnology Key Laboratory, Wuhan University, Wuhan, Hubei, People's Republic of China
| | - Wenting Huang
- Department of Occupational and Environmental Health, School of Public Health, Wuhan University, Wuhan, Hubei, People's Republic of China
- Hubei Key Laboratory of Allergy and Immune-Related Diseases, Wuhan, Hubei, People's Republic of China
- Hubei Biomass-Resource Chemistry and Environmental Biotechnology Key Laboratory, Wuhan University, Wuhan, Hubei, People's Republic of China
| | - Yongyi Bi
- Department of Occupational and Environmental Health, School of Public Health, Wuhan University, Wuhan, Hubei, People's Republic of China
- Hubei Key Laboratory of Allergy and Immune-Related Diseases, Wuhan, Hubei, People's Republic of China
- Hubei Biomass-Resource Chemistry and Environmental Biotechnology Key Laboratory, Wuhan University, Wuhan, Hubei, People's Republic of China
| | - Hong Wang
- Department of Occupational and Environmental Health, School of Public Health, Wuhan University, Wuhan, Hubei, People's Republic of China
- Hubei Key Laboratory of Allergy and Immune-Related Diseases, Wuhan, Hubei, People's Republic of China
- Hubei Biomass-Resource Chemistry and Environmental Biotechnology Key Laboratory, Wuhan University, Wuhan, Hubei, People's Republic of China
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Aberrant expression of Sonic hedgehog signaling in Peutz-Jeghers syndrome. Hum Pathol 2015; 50:153-61. [PMID: 26997450 DOI: 10.1016/j.humpath.2015.09.044] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Revised: 09/16/2015] [Accepted: 09/18/2015] [Indexed: 12/21/2022]
Abstract
The SHH signaling pathway is critical for gastrointestinal development and organic patterning, and dysregulation of SHH pathway molecules has been detected in multiple gastrointestinal neoplasms. This study investigated the role of the SHH signaling pathway in PJS. Expression of SHH, PTCH, and GLI1 was examined by real-time PCR and immunohistochemistry in 20 normal tissues and 75 colorectal lesions (25 PJPs, 25 adenomas, and 25 adenocarcinomas). Expression of SHH, PTCH, and GLI1 mRNA was higher in PJPs than in normal tissue (P < .05) and gradually increased along the PJP-adenoma-adenocarcinoma sequence (P < .05). Immunostaining indicated that SHH expression was present in 60% of PJPs, 72% of adenomas, and 84% of carcinomas, whereas 68% of PJPs, 72% of adenomas, and 88% of carcinomas exhibited cytoplasmic expression of PTCH. Moreover, high GLI1 expression was detected in 56% of PJPs, 64% of adenomas, and 80% of carcinomas; and high nuclear expression of GLI1 was observed in 8 adenomas with atypia and 15 carcinomas. Increased SHH, PTCH, and GLI1 protein correlated positively with tumor grade (P = .012, P = .003, and P = .007, respectively), tumor depth (P = .024, P = .007, and P = .01), and lymph node metastasis (P = .05, P = .015, and P = .005). This study identified aberrant expression of SHH pathway molecules in PJS, and the findings may supply a novel mechanism for the development of PJ polyps.
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Recent progress on liver kinase B1 (LKB1): expression, regulation, downstream signaling and cancer suppressive function. Int J Mol Sci 2014; 15:16698-718. [PMID: 25244018 PMCID: PMC4200829 DOI: 10.3390/ijms150916698] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Revised: 08/12/2014] [Accepted: 08/28/2014] [Indexed: 12/15/2022] Open
Abstract
Liver kinase B1 (LKB1), known as a serine/threonine kinase, has been identified as a critical cancer suppressor in many cancer cells. It is a master upstream kinase of 13 AMP-activated protein kinase (AMPK)-related protein kinases, and possesses versatile biological functions. LKB1 gene is mutated in many cancers, and its protein can form different protein complexes with different cellular localizations in various cell types. The expression of LKB1 can be regulated through epigenetic modification, transcriptional regulation and post-translational modification. LKB1 dowcnstream pathways mainly include AMPK, microtubule affinity regulating kinase (MARK), salt-inducible kinase (SIK), sucrose non-fermenting protein-related kinase (SNRK) and brain selective kinase (BRSK) signalings, etc. This review, therefore, mainly discusses recent studies about the expression, regulation, downstream signaling and cancer suppressive function of LKB1, which can be helpful for better understanding of this molecular and its significance in cancers.
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Abstract
LKB1 is commonly thought of as a tumor suppressor gene because its hereditary mutation is responsible for a cancer syndrome, and somatic inactivation of LKB1 is found in non-small cell lung cancer, melanoma, and cervical cancers. However, unlike other tumor suppressors whose main function is to either suppress cell proliferation or promote cell death, one of the functions of LKB1-regulated AMPK signaling is to suppress cell proliferation in order to promote cell survival under energetic stress conditions. This unique, pro-survival function of LKB1 has led to the discovery of reagents, such as phenformin, that specifically exploit the vulnerability of LKB1-null cells in their defect in sensing energetic stress. Such targeted agents represent a novel treatment strategy because they induce cell killing when LKB1 is absent. This review article summarizes various vulnerabilities of LKB1-mutant cells that have been reported in the literature and discusses the potential of using existing or developing novel reagents to target cancer cells with defective LKB1.
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Affiliation(s)
- Wei Zhou
- Corresponding author. Departments of Hematology and Medical Oncology, Emory University School of Medicine, 1365 Clifton Road, NE, Suite C4084, Atlanta 30322, Georgia. Tel.: +995 404 778 2134; fax: +995 404 778 5530.
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11
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Zhang X, Chen H, Wang X, Zhao W, Chen JJ. Expression and transcriptional profiling of the LKB1 tumor suppressor in cervical cancer cells. Gynecol Oncol 2014; 134:372-8. [PMID: 24792998 DOI: 10.1016/j.ygyno.2014.04.050] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2014] [Revised: 04/23/2014] [Accepted: 04/25/2014] [Indexed: 12/19/2022]
Abstract
OBJECTIVES To characterize the biological activities of LKB1, examine LKB1 protein expression and identify LKB1-regulated genes that may serve as therapeutic targets in cervical cancer. METHODS Proliferation of cervical cancer HeLa cells expressing LKB1 was examined. LKB1 expression in normal cervical tissues and cervical cancers was assessed by immunohistochemistry. Gene expression profiles of cervical cancer HeLa cells stably expressing LKB1 were analyzed by microarray. Differentially expressed genes were analyzed using Gene Ontology (GO) terms and the Kyoto Encyclopedia of Genes and Genomes (KEGG) PATHWAY database. Quantitative RT-PCR was used to validate the microarray data. The expression of lipid phosphatase inositol polyphosphate 4-phosphatase type II (INPP4B) was confirmed by western blotting. RESULTS Expression of LKB1 inhibited HeLa cell proliferation, activated AMPK and was lost in more than 50% of cervical carcinomas. More than 200 genes were differentially expressed between HeLa cells with and without LKB1. Bioinformatics analysis with GO annotation indicated that LKB1 plays a role in receiving diverse stimuli and converting them into molecular signals. KEGG PATHWAY analysis showed that 8 pathways were significantly regulated. These include arginine and proline metabolism and inositol phosphate metabolism. The differential expression of 7 randomly selected genes was confirmed by quantitative RT-PCR. Furthermore, the steady-state level of INPP4B protein was up-regulated in LKB1-overexpressing cells. CONCLUSIONS This study establishes LKB1 as an important tumor suppressor in cervical cancer and sheds light on a novel signaling pathway regulated by LKB1.
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Affiliation(s)
- Xiaoli Zhang
- Department of Microbiology, Shandong University School of Medicine, Jinan, Shandong, China; Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01532, USA
| | - Hanxiang Chen
- Department of Microbiology, Shandong University School of Medicine, Jinan, Shandong, China
| | - Xiao Wang
- Department of Pathology, Shandong University School of Medicine, Jinan, Shandong, China
| | - Weiming Zhao
- Department of Microbiology, Shandong University School of Medicine, Jinan, Shandong, China.
| | - Jason J Chen
- Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01532, USA; Cancer Research Center, Shandong University School of Medicine, Jinan, Shandong, China.
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12
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Abstract
Hepatocytes, like other epithelia, are situated at the interface between the organism's exterior and the underlying internal milieu and organize the vectorial exchange of macromolecules between these two spaces. To mediate this function, epithelial cells, including hepatocytes, are polarized with distinct luminal domains that are separated by tight junctions from lateral domains engaged in cell-cell adhesion and from basal domains that interact with the underlying extracellular matrix. Despite these universal principles, hepatocytes distinguish themselves from other nonstriated epithelia by their multipolar organization. Each hepatocyte participates in multiple, narrow lumina, the bile canaliculi, and has multiple basal surfaces that face the endothelial lining. Hepatocytes also differ in the mechanism of luminal protein trafficking from other epithelia studied. They lack polarized protein secretion to the luminal domain and target single-spanning and glycosylphosphatidylinositol-anchored bile canalicular membrane proteins via transcytosis from the basolateral domain. We compare this unique hepatic polarity phenotype with that of the more common columnar epithelial organization and review our current knowledge of the signaling mechanisms and the organization of polarized protein trafficking that govern the establishment and maintenance of hepatic polarity. The serine/threonine kinase LKB1, which is activated by the bile acid taurocholate and, in turn, activates adenosine monophosphate kinase-related kinases including AMPK1/2 and Par1 paralogues has emerged as a key determinant of hepatic polarity. We propose that the absence of a hepatocyte basal lamina and differences in cell-cell adhesion signaling that determine the positioning of tight junctions are two crucial determinants for the distinct hepatic and columnar polarity phenotypes.
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Affiliation(s)
- Aleksandr Treyer
- Albert Einstein College of Medicine, Department of Developmental and Molecular Biology, Bronx, New York, USA
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LKB1 downregulation may be independent of promoter methylation or FOXO3 expression in head and neck cancer. Transl Res 2013; 162:122-9. [PMID: 23810581 DOI: 10.1016/j.trsl.2013.06.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 05/30/2013] [Accepted: 06/03/2013] [Indexed: 01/29/2023]
Abstract
The serine/threonine kinase liver kinase B 1 (LKB1) is a multifunctional protein and has been associated with various cancer types. Although the tumor suppressor function of LKB1 is attributed mainly to its ability to phosphorylate directly different adenosine monophosphate-activated protein kinases, its regulation is still poorly understood. More recently, it has been shown that LKB1 expression can be regulated by forkhead box O transcription factors via cis-acting elements, which are found in the promoter region of the LKB1 gene. In this study, we investigated LKB1 messenger RNA expression levels in association with the promoter methylation of the gene and forkhead box O member 3 (FOXO3) messenger RNA expression in head and neck squamous cell carcinoma (HNSCC) tumor samples. Our results show that LKB1 expression is downregulated, especially in advanced-stage tumor samples, and this downregulation was not the result of promoter methylation or modulation by FOXO3 (P = 0.656). Despite observing a positive association between the LKB1 and FOXO3 expression levels in the tumors, this association was not statistically significant (P = 0.24). Our results indicate that downregulation of LKB1 is independent of FOXO3 and may be implicated in the progression of HNSCC.
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Zhong DS, Sun LL, Dong LX. Molecular mechanisms of LKB1 induced cell cycle arrest. Thorac Cancer 2013; 4:229-233. [PMID: 28920233 DOI: 10.1111/1759-7714.12003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2012] [Accepted: 10/02/2012] [Indexed: 01/13/2023] Open
Abstract
LKB1 is a serine/threonine protein kinase mutated in patients with Peutz-Jeghers syndrome. Biallelic inactivation of LKB1 is present in up to 30% of cases of non-small cell lung cancer (NSCLC). As a tumor suppressor, LKB1 functions in arresting the cell cycle and inhibiting cell growth. LKB1 leads to induction of p21/WAF1 expression in a p53-dependent mechanism, which is mediated by cytoplasmic LKB1 initiating negative regulation of cell growth or nuclear LKB1 directly involved in transcriptional regulation of p21/WAF1. Alternatively, p53 and p21/WAF1-independent mechanism of regulating cell cycle by LKB1 is also reported.
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Affiliation(s)
- Dian-Sheng Zhong
- Department of Respiratory Medicine, Tianjin Medical University General Hospital, Tianjin, China.,Tianjin Lung Cancer Institute, Tianjin Medical University General Hospital, Tianjin, China
| | - Lin-Lin Sun
- Tianjin Lung Cancer Institute, Tianjin Medical University General Hospital, Tianjin, China
| | - Li-Xia Dong
- Department of Respiratory Medicine, Tianjin Medical University General Hospital, Tianjin, China
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Zhu H, Moriasi CM, Zhang M, Zhao Y, Zou MH. Phosphorylation of serine 399 in LKB1 protein short form by protein kinase Cζ is required for its nucleocytoplasmic transport and consequent AMP-activated protein kinase (AMPK) activation. J Biol Chem 2013; 288:16495-16505. [PMID: 23612973 PMCID: PMC3675585 DOI: 10.1074/jbc.m112.443580] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 04/21/2013] [Indexed: 11/06/2022] Open
Abstract
Two splice variants of LKB1 exist: LKB1 long form (LKB1(L)) and LKB1 short form (LKB1(S)). In a previous study, we demonstrated that phosphorylation of Ser-428/431 (in LKB1(L)) by protein kinase Cζ (PKCζ) was essential for LKB1-mediated activation of AMP-activated protein kinase (AMPK) in response to oxidants or metformin. Paradoxically, LKB1S also activates AMPK although it lacks Ser-428/431. Thus, we hypothesized that LKB1(S) contained additional phosphorylation sites important in AMPK activation. Truncation analysis and site-directed mutagenesis were used to identify putative PKCζ phosphorylation sites in LKB1(S). Substitution of Ser-399 to alanine did not alter the activity of LKB1(S), but abolished peroxynitrite- and metformin-induced activation of AMPK. Furthermore, the phosphomimetic mutation (S399D) increased the phosphorylation of AMPK and its downstream target phospho-acetyl-coenzyme A carboxylase (ACC). PKCζ-dependent phosphorylation of Ser-399 triggered nucleocytoplasmic translocation of LKB1(S) in response to metformin or peroxynitrite treatment. This effect was ablated by pharmacological and genetic inhibition of PKCζ, by inhibition of CRM1 activity and by substituting Ser-399 with alanine (S399A). Overexpression of PKCζ up-regulated metformin-mediated phosphorylation of both AMPK (Thr-172) and ACC (Ser-79), but the effect was ablated in the S399A mutant. We conclude that, similar to Ser-428/431 (in LKB1(L)), Ser-399 (in LKB1(S)) is a PKCζ-dependent phosphorylation site essential for nucleocytoplasmic export of LKB1(S) and consequent AMPK activation.
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Affiliation(s)
- Huaiping Zhu
- Section of Molecular Medicine, Department of Medicine, Oklahoma City, Oklahoma 73013
| | - Cate M Moriasi
- Section of Molecular Medicine, Department of Medicine, Oklahoma City, Oklahoma 73013
| | - Miao Zhang
- Section of Molecular Medicine, Department of Medicine, Oklahoma City, Oklahoma 73013
| | - Yu Zhao
- Section of Molecular Medicine, Department of Medicine, Oklahoma City, Oklahoma 73013
| | - Ming-Hui Zou
- Section of Molecular Medicine, Department of Medicine, Oklahoma City, Oklahoma 73013; Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73013.
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16
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Mishra N, Hall J. Identification of patients at risk for hereditary colorectal cancer. Clin Colon Rectal Surg 2013; 25:67-82. [PMID: 23730221 DOI: 10.1055/s-0032-1313777] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Diagnosis of hereditary colorectal cancer syndromes requires clinical suspicion and knowledge of such syndromes. Lynch syndrome is the most common cause of hereditary colorectal cancer. Other less common causes include familial adenomatous polyposis (FAP), Peutz-Jeghers syndrome (PJS), juvenile polyposis syndrome, and others. There have been a growing number of clinical and molecular tools used to screen and test at risk individuals. Screening tools include diagnostic clinical criteria, family history, genetic prediction models, and tumor testing. Patients who are high risk based on screening should be referred for genetic testing.
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Affiliation(s)
- Nitin Mishra
- Department of Colon and Rectal Surgery, Lahey Clinic, Burlington, Massachusetts
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Abstract
Initially identified as the Caenorhabditis elegans PAR-4 homologue, the serine threonine kinase LKB1 is conserved throughout evolution and ubiquitously expressed. In humans, LKB1 is causally linked to the Peutz-Jeghers syndrome and is one of the most commonly mutated genes in several cancers like lung and cervical carcinomas. These observations have led to classify LKB1 as tumour suppressor gene. Although, considerable dark zones remain, an impressive leap in the understanding of LKB1 functions has been done during the last decade. Role of LKB1 as a major actor of the AMPK/mTOR pathway connecting cellular metabolism, cell growth and tumorigenesis has been extensively studied probably to the detriment of other functions of equal importance. This review will discuss about LKB1 activity regulation, its effectors and clues on their involvement in cell polarity.
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18
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Abstract
Although inherited predisposition to colorectal cancer (CRC) has been suspected for more than 100 years, definitive proof of Mendelian syndromes had to await maturation of molecular genetic technologies. Since the l980s, the genetics of several clinically distinct entities has been revealed. Five disorders that share a hereditary predisposition to CRC are reviewed in this article.
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Herrmann JL, Byekova Y, Elmets CA, Athar M. Liver kinase B1 (LKB1) in the pathogenesis of epithelial cancers. Cancer Lett 2011; 306:1-9. [PMID: 21450399 DOI: 10.1016/j.canlet.2011.01.014] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Revised: 01/16/2011] [Accepted: 01/19/2011] [Indexed: 12/26/2022]
Abstract
LKB1 acts as a master kinase, with its major protein targets being the family of AMPKs. Through activation of multiple signaling pathways, LKB1's main physiologic functions involve regulating cellular growth, metabolism, and polarity. Germline mutations in LKB1 result in Peutz-Jeghers Syndrome, a rare cancer susceptibility syndrome. In addition, multiple LKB1 mutations have been identified in sporadic cancers, especially those of the lung. Recent studies from a variety of murine models have helped characterize LKB1's role in the pathogenesis of epithelial cancers. In some tumor types, LKB1 might function chiefly to suppress cell growth or invasion, while in other cases, it may serve to prevent metastasis. Moreover, molecular signatures of individual tumors likely influence LKB1's operational role, as multiple studies have shown that LKB1 can synergize with other tumor suppressors and/or oncogenes to accelerate tumorigenesis. To date, LKB1 has been considered mainly a tumor suppressor; however, some studies have suggested its potential oncogenic role, mainly through the suppression of apoptosis. In short, LKB1 is a tissue and context-specific kinase. This review aims to summarize our current understanding of its role in the pathogenesis of epithelial cancers.
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Gao Y, Zhang FM, Huang S, Wang X, Zhang P, Huang XD, Ji GZ, Fan ZN. A De Novo mutation of STK11 gene in a Chinese patient with Peutz-Jeghers syndrome. Dig Dis Sci 2010; 55:1032-6. [PMID: 19507030 DOI: 10.1007/s10620-009-0837-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2009] [Accepted: 04/30/2009] [Indexed: 12/09/2022]
Abstract
Peutz-Jeghers syndrome (PJS) is an autosomal-dominant inherited disorder characterized by mucocutaneous pigmentation, hamartomatous polyposis of the gastrointestinal tract, and an increased risk for the development of both gastrointestinal and extraintestinal malignancies. Germline mutation of the STK11 gene, which encodes a serine-threonine kinase, is responsible for PJS. We collected blood samples from a Chinese PJS family consisting of a total of four individuals (one male and three females) including one PJS patient. The whole coding region of STK11 was amplified by polymerase chain reaction and products analyzed by direct sequencing. Molecular analysis of the STK11 gene in this case of PJS revealed a substitution of thymine 217 for adenine (C.217T > A) in exon 1, resulting in a change of codon 73 from cysteine to serine (C73S). The point mutation was not found in normal individuals in this PJS family or in 100 control individuals. The results presented here enlarge the spectrum of mutations of the STK11 gene by identifying a de novo mutation in a PJS patient and further support the hypothesis that STK11 mutations are disease-causing mutations for PJS.
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Affiliation(s)
- Ying Gao
- Institute of Digestive Endoscopy and Medical Center for Digestive Diseases, Second Affiliated Hospital of Nanjing Medical University, 210011, Nanjing, China
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21
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Chari M, Lam C, Lam T. Hypothalamic Fatty Acid Sensing in the Normal and Disease States. Front Neurosci 2009. [DOI: 10.1201/9781420067767-c20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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Xie Z, Dong Y, Zhang J, Scholz R, Neumann D, Zou MH. Identification of the serine 307 of LKB1 as a novel phosphorylation site essential for its nucleocytoplasmic transport and endothelial cell angiogenesis. Mol Cell Biol 2009; 29:3582-96. [PMID: 19414597 PMCID: PMC2698771 DOI: 10.1128/mcb.01417-08] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2008] [Revised: 10/17/2008] [Accepted: 04/26/2009] [Indexed: 11/20/2022] Open
Abstract
LKB1, a master kinase that controls at least 13 downstream protein kinases including the AMP-activated protein kinase (AMPK), resides mainly in the nucleus. A key step in LKB1 activation is its export from the nucleus to the cytoplasm. Here, we identified S307 of LKB1 as a putative novel phosphorylation site which is essential for its nucleocytoplasmic transport. In a cell-free system, recombinant PKC-zeta phosphorylates LKB1 at S307. AMPK-activating agents stimulate PKC-zeta activity and LKB1 phosphorylation at S307 in endothelial cells, hepatocytes, skeletal muscle cells, and vascular smooth muscle cells. Like the kinase-dead LKB1 D194A mutant (mutation of Asp194 to Ala), the constitutively nucleus-localized LKB1 SL26 mutant and the LKB1 S307A mutant (Ser307 to Ala) exhibit a decreased association with STRAD alpha. Interestingly, the PKC-zeta consensus sequence surrounding LKB1 S307 is disrupted in the LKB1 SL26 mutant, thus providing a likely molecular explanation for this mutation causing LKB1 dysfunction. In addition, LKB1 nucleocytoplasmic transport and AMPK activation in response to peroxynitrite are markedly reduced by pharmacological inhibition of CRM1, which normally facilitates nuclear export of LKB1-STRAD complexes. In comparison to the LKB1 wild type, the S307A mutant complexes show reduced association with CRM1. Finally, adenoviral overexpression of wild-type LKB1 suppresses, while the LKB1 S307A mutant increases, tube formation and hydrogen peroxide-enhanced apoptosis in cultured endothelial cells. Taken together, our results suggest that, in multiple cell types the signaling pathways engaged by several physiological stimuli converge upon PKC-zeta-dependent LKB1 phosphorylation at S307, which directs the nucleocytoplasmic transport of LKB1 and consequent AMPK activation.
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Affiliation(s)
- Zhonglin Xie
- Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
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Fan D, Ma C, Zhang H. The molecular mechanisms that underlie the tumor suppressor function of LKB1. Acta Biochim Biophys Sin (Shanghai) 2009; 41:97-107. [PMID: 19204826 DOI: 10.1093/abbs/gmn011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Germline mutations of the LKB1 tumor suppressor gene result in Peutz-Jeghers syndrome (PJS) characterized by intestinal hamartomas and increased incidence of epithelial cancers. Inactivating mutations in LKB1 have also been found in certain sporadic human cancers and with particularly high frequency in lung cancer. LKB1 has now been demonstrated to play a crucial role in pulmonary tumorigenesis, controlling initiation, differentiation, and metastasis. Recent evidences showed that LKB1 is a multitasking kinase, with great potential in orchestrating cell activity. Thus far, LKB1 has been found to play a role in cell polarity, energy metabolism, apoptosis, cell cycle arrest, and cell proliferation, all of which may require the tumor suppressor function of this kinase and/or its catalytic activity. This review focuses on remarkable recent findings concerning the molecular mechanism by which the LKB1 protein kinase operates as a tumor suppressor and discusses the rational treatment strategies to individuals suffering from PJS and other common disorders related to LKB1 signaling.
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Affiliation(s)
- Dahua Fan
- Department of Biochemistry and Molecular Biology, Guangdong Medical College, Zhanjiang, China
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Lkb1 deficiency alters goblet and paneth cell differentiation in the small intestine. PLoS One 2009; 4:e4264. [PMID: 19165340 PMCID: PMC2626247 DOI: 10.1371/journal.pone.0004264] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2008] [Accepted: 12/08/2008] [Indexed: 11/19/2022] Open
Abstract
The Lkb1 tumour suppressor is a multitasking kinase participating in a range of physiological processes. We have determined the impact of Lkb1 deficiency on intestinal homeostasis, particularly focussing on secretory cell differentiation and development since we observe strong expression of Lkb1 in normal small intestine Paneth and goblet cells. We crossed mice bearing an Lkb1 allele flanked with LoxP sites with those carrying a Cyp1a1-specific inducible Cre recombinase. Lkb1 was efficiently deleted from the epithelial cells of the mouse intestine after intraperitoneal injection of the inducing agent beta-naphthoflavone. Bi-allelic loss of Lkb1 led to the perturbed development of Paneth and goblet cell lineages. These changes were characterised by the lack of Delta ligand expression in Lkb1-deficient secretory cells and a significant increase in the levels of the downstream Notch signalling effector Hes5 but not Hes1. Our data show that Lkb1 is required for the normal differentiation of secretory cell lineages within the intestine, and that Lkb1 deficiency modulates Notch signalling modulation in post-mitotic cells.
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Hutchinson DS, Summers RJ, Bengtsson T. Regulation of AMP-activated protein kinase activity by G-protein coupled receptors: Potential utility in treatment of diabetes and heart disease. Pharmacol Ther 2008; 119:291-310. [DOI: 10.1016/j.pharmthera.2008.05.008] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2008] [Accepted: 05/27/2008] [Indexed: 12/25/2022]
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Thornton C, Sardini A, Carling D. Muscarinic receptor activation of AMP-activated protein kinase inhibits orexigenic neuropeptide mRNA expression. J Biol Chem 2008; 283:17116-22. [PMID: 18436530 DOI: 10.1074/jbc.m708987200] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
AMP-activated protein kinase (AMPK) plays a crucial role in both cellular and whole body energy homeostasis. Here we demonstrate that the muscarinic receptor agonist carbachol activates AMPKalpha1-containing complexes in the human SH-SY5Y cell line via a mechanism specific for the AMPK upstream kinase, Ca(2+)/calmodulin-dependent protein kinase kinase beta. Activation of AMPK inhibits mRNA expression of the orexigenic neuropeptides Agouti-related peptide and melanin-concentrating hormone but surprisingly has no effect on neuropeptide Y mRNA, a neuropeptide previously shown to be regulated by AMPK. Rather than restoring mRNA levels to baseline, pharmacological inhibition of Ca(2+)/calmodulin-dependent protein kinase kinase beta or AMPK greatly increases Agouti-related peptide and melanin-concentrating hormone mRNA expression. These data support a hypothesis that modulating basal AMPK activity in the hypothalamus is essential for maintaining tight regulation of pathways contributing to food intake.
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Affiliation(s)
- Claire Thornton
- Medical Research Council (MRC) Cellular Stress Group, MRC Clinical Sciences Centre, Du Cane Road, London W12 0NN, United Kingdom.
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Amin RMS, Hiroshima K, Miyagi Y, Kokubo T, Hoshi K, Fujisawa T, Nakatani Y. Role of the PI3K/Akt, mTOR, and STK11/LKB1 pathways in the tumorigenesis of sclerosing hemangioma of the lung. Pathol Int 2008; 58:38-44. [PMID: 18067639 DOI: 10.1111/j.1440-1827.2007.02186.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Although the histogenesis of sclerosing hemangioma (SH) of the lung is now thought to be respiratory epithelial in origin, the genetic abnormalities that mediate its development are not known. Because pathophysiology of several syndromes associated with benign tumors may converge on the tuberous sclerosis complex (TSC), serine/threonine kinase 11 (STK11), and mammalian target of rapamycin (mTOR) pathways, the purpose of the present paper was to investigate their roles in the development of SH. Semiquantitative immunohistochemical analysis was done to assess the expression of phospho-mTOR, phospho-S6 ribosomal protein, phosphatase and tensin homolog deleted on chromosome 10 (PTEN), phospho-Akt, STK11, tuberin, hamartin, vascular endothelial growth factor (VEGF), and hypoxia-inducible factor-1alpha (HIF-1alpha) in 19 cases of typical SH. To determine whether genetic alteration of STK11 is involved in the development of SH, all encoding exons of STK11 were analyzed by polymerase chain reaction (PCR) amplification and direct sequencing of genomic DNA of six specimens. The six specimens were also investigated for whether promoter hypermethylation exists as an alternative inactivating mechanism for STK11. All specimens showed moderate to marked reaction to phospho-S6 ribosomal protein and PTEN; 16 specimens (84%) showed slight to moderate reaction to phospho-mTOR, negative reaction to STK11, and slight to moderate reaction to hamartin; 11 (58%) showed slight to moderate reaction to phospho-Akt; 18 (95%) showed slight to moderate reaction to tuberin and positive reaction for HIF-1alpha; and 17 (90%) showed moderate reaction to VEGF. No somatic mutation of STK11 was found and the six specimens were unmethylated in the promoter region. These data imply that aberrant mTOR signaling may play a role in the development of SH, and its vascular nature may be due partially to high levels of VEGF caused by dysregulation of mTOR signaling.
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Affiliation(s)
- Randa M S Amin
- Department of Diagnostic Pathology, Chiba University Graduate School of Medicine, Chuo-ku, Chiba, Japan
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Dilmeç F, Varışlı L, Özgönül A, Cen O. Analysis Of STK11/LKB1 Gene Using Bioinformatics Tools. ELECTRONIC JOURNAL OF GENERAL MEDICINE 2007. [DOI: 10.29333/ejgm/82526] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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29
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Sanchez-Cespedes M. A role for LKB1 gene in human cancer beyond the Peutz-Jeghers syndrome. Oncogene 2007; 26:7825-32. [PMID: 17599048 DOI: 10.1038/sj.onc.1210594] [Citation(s) in RCA: 169] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Germline LKB1 mutations are responsible for Peutz-Jeghers syndrome (PJS). Tumors at several locations frequently arise in these patients, confirming that LKB1 is linked to cancer predisposition and is therefore a bona fide tumor-suppressor gene. In humans, the LKB1 gene is located in the short arm of chromosome 19, which is frequently deleted in many tumors of sporadic origin. However, LKB1 alterations in tumors other than those of PJS are rarely reported. Notably, this is not the case for non-small-cell lung cancer, where nearly half of the tumors harbor somatic and homozygous inactivating mutations in LKB1. The present review considers the frequency and pattern of LKB1 gene mutations in sporadic cancers of various origins, and the role of the encoded protein in cancer development.
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Affiliation(s)
- M Sanchez-Cespedes
- Molecular Pathology Programme, Spanish National Cancer Centre (CNIO), Melchor Fernandez Almagro, Madrid, Spain.
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Conde E, Suarez-Gauthier A, García-García E, Lopez-Rios F, Lopez-Encuentra A, García-Lujan R, Morente M, Sanchez-Verde L, Sanchez-Cespedes M. Specific pattern of LKB1 and phospho-acetyl-CoA carboxylase protein immunostaining in human normal tissues and lung carcinomas. Hum Pathol 2007; 38:1351-60. [PMID: 17521700 DOI: 10.1016/j.humpath.2007.01.022] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2006] [Revised: 11/03/2006] [Accepted: 01/23/2007] [Indexed: 12/11/2022]
Abstract
The LKB1 tumor suppressor gene codes for a serine/threonine protein kinase, and among its substrates is the adenosine monophosphate-dependent protein kinase, a sensor of intracellular energy levels. LKB1 is genetically inactivated in several types of tumors, especially lung adenocarcinomas. Here we used immunohistochemistry to evaluate the levels of LKB1 and the phosphorylated form of the acetyl-CoA carboxylase (ACC) protein in a variety of human adult normal tissues and in 159 lung carcinomas. The enzyme ACC becomes inactive upon phosphorylation by adenosine monophosphate-dependent protein kinase. Our analysis in normal tissues revealed strong LKB1 immunostaining in most epithelia, in the seminiferous tubules of the testis, in myocytes from skeletal muscle, and in glia cells. In contrast to the cytosolic location of LKB1 found in most tissues, glia cells carried mainly nuclear LKB1. Some epithelial cells showed apical accumulation of LKB1, supporting its role in cell polarity. Regarding phospho-ACC (p-ACC), strong immunostaining was observed in myocytes from the skeletal muscle and heart, and in Leydig cells of the testis. In lung tumors, LKB1 immunostaining was absent, moderate, and high in 20%, 61%, and 19% of the tumors, respectively, whereas p-ACC immunostaining was found to be absent/low, moderate, and high in 35%, 34%, and 31% of the tumors, respectively. High levels of LKB1 and p-ACC immunostaining predominated in lung adenocarcinomas compared with squamous cell carcinomas. Finally, high p-ACC was an independent marker for prediction of better survival in lung adenocarcinoma patients. Median overall survival was longer in patients with p-ACC-positive than those with p-ACC-negative tumors (96 versus 44 months, P = .04). In conclusion, our observations provide complete information about the pattern and levels of LKB1 and p-ACC immunostaining in normal tissues and in lung tumors, and highlight the special relevance of abnormalities of the LKB1 pathway in lung adenocarcinoma.
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Affiliation(s)
- Esther Conde
- Lung Cancer Group, Pathology Programme, Spanish National Cancer Centre (CNIO), 28029 Madrid, Spain
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Zhuang ZG, Di GH, Shen ZZ, Ding J, Shao ZM. Enhanced expression of LKB1 in breast cancer cells attenuates angiogenesis, invasion, and metastatic potential. Mol Cancer Res 2007; 4:843-9. [PMID: 17114342 DOI: 10.1158/1541-7786.mcr-06-0118] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
LKB1 (also known as STK11) is a recently identified tumor suppressor gene whose mutation can lead to Peutz-Jeghers syndrome, which is characterized by gastrointestinal polyps and cancers of different organ systems. Approximately 30% of sporadic breast cancer samples express low levels of LKB1. This suggests that the LKB1 gene may be related to the tumorigenesis of breast cancer. We reintroduced LKB1 into MDA-MB-435 breast cancer cells that lack the LKB1 gene to investigate how overexpression of LKB1 affects tumor invasiveness and metastasis. Overexpression of the LKB1 protein in breast cancer cells resulted in significant inhibition of in vitro invasion. In vivo, LKB1 expression reduced tumor growth in the mammary fat pad, microvessel density, and lung metastasis. LKB1 overexpression was associated with down-regulation of matrix metalloproteinase-2, matrix metalloproteinase-9, vascular endothelial growth factor, and basic fibroblast growth factor mRNA and protein levels. Overexpression of the LKB1 protein in human breast cancer is significantly associated with a decrease in microvessel density. Our results indicate that LKB1 plays a negative regulatory role in human breast cancer, a finding that may lead to a new therapeutic strategy.
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Affiliation(s)
- Zhi-Gang Zhuang
- Breast Cancer Institute, Cancer Hospital, Department of Oncology, Shanghai Medical College, Institutes of Biomedical Science, Fudan University, Shanghai, People's Republic of China
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Noga AA, Soltys CLM, Barr AJ, Kovacic S, Lopaschuk GD, Dyck JRB. Expression of an active LKB1 complex in cardiac myocytes results in decreased protein synthesis associated with phenylephrine-induced hypertrophy. Am J Physiol Heart Circ Physiol 2006; 292:H1460-9. [PMID: 17098823 DOI: 10.1152/ajpheart.01133.2006] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
AMP-activated protein kinase (AMPK) is a major metabolic regulator in the cardiac myocyte. Recently, LKB1 was identified as a kinase that regulates AMPK. Using immunoblot analysis, we confirmed high expression of LKB1 in isolated rat cardiac myocytes but show that, under basal conditions, LKB1 is primarily localized to the nucleus, where it is inactive. We examined the role of LKB1 in cardiac myocytes, using adenoviruses that express LKB1, and its binding partners Ste20-related adaptor protein (STRADalpha) and MO25alpha. Infection of neonatal rat cardiac myocytes with all three adenoviruses substantially increased LKB1/STRADalpha/MO25alpha expression, LKB1 activity, and AMPKalpha phosphorylation at its activating phosphorylation site (threonine-172). Since activation of AMPK can inhibit hypertrophic growth and since LKB1 is upstream of AMPK, we hypothesized that expression of an active LKB1 complex would also inhibit protein synthesis associated with hypertrophic growth. Expression of the LKB1/STRADalpha/MO25alpha complex in neonatal rat cardiac myocytes inhibited the increase in protein synthesis observed in cells treated with phenylephrine (measured via [(3)H]phenylalanine incorporation). This was associated with a decreased phosphorylation of p70S6 kinase and its substrate S6 ribosomal protein, key regulators of protein synthesis. In addition, we show that the pathological cardiac hypertrophy in transgenic mice with cardiac-specific expression of activated calcineurin is associated with a significant decrease in LKB1 expression. Together, our data show that increased LKB1 activity in the cardiac myocyte can decrease hypertrophy-induced protein synthesis and suggest that LKB1 activation may be a method for the prevention of pathological cardiac hypertrophy.
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Affiliation(s)
- Anna A Noga
- Cardiovascular Research Group, Department of Pediatrics, Faculty of Medicine and Dentistry, Univ of Alberta, Edmonton, Alberta, Canada
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Qiu W, Schönleben F, Thaker HM, Goggins M, Su. GH. A novel mutation of STK11/LKB1 gene leads to the loss of cell growth inhibition in head and neck squamous cell carcinoma. Oncogene 2006; 25:2937-42. [PMID: 16407837 PMCID: PMC1459486 DOI: 10.1038/sj.onc.1209325] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
To investigate whether genetic alteration of the STK11 (serine/threonine kinase 11)/LKB1 tumor-suppressor gene is involved in the carcinogenesis of head and neck squamous cell carcinoma (HNSCC), the entire encoding exons and flanking intronic sequences of the STK11/LKB1 gene were analysed with direct genomic sequencing of 15 HNSCC specimens. A novel missense mutation with presumed loss of heterozygosity (LOH) and 10 polymorphisms were identified in these samples. The novel mutation of STK11/LKB1 at nucleotide position 613 G --> A, which causes the amino-acid substitution from alanine to threonine at residue 205 within the catalytic kinase domain, was identified in cell line RPMI 2650. To further determine whether this point mutation affects the gene function, constructs of the wild type and A205T mutant of the STK11/LKB1 gene expression vectors were created and transfected into RPMI 2650 cells. Our results showed that the reintroduction of the wild-type but not the mutant STK11/LKB1 construct into RPMI 2650 cells induced suppression of the cell growth. The mutation also affected the kinase activity of the Stk11/Lkb1 protein. This led us to conclude that the A205T point mutation of the STK11/LKB1 gene produces functionally inactive proteins. This is the first described mutation of the STK11/LKB1 gene in HNSCC. While the mutation frequency of the STK11/LKB1 gene in HNSCC remains to be determined in future studies, our data strongly suggests that STK11/LKB1 is involved in the carcinogenesis of HNSCC.
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Affiliation(s)
- Wanglong Qiu
- The Department of Otolaryngology and Head and Neck Surgery and
| | | | - Harshwardhan M. Thaker
- the Department of Pathology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
| | - Michael Goggins
- Departments of Medicine, Pathology, and Oncology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Gloria H. Su.
- The Department of Otolaryngology and Head and Neck Surgery and
- the Department of Pathology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
- To whom requests for reprints should be addressed: Dr. Su at the Department of Otolaryngology/Head and Neck Surgery, Columbia University College of Physicians and Surgeons, 1130 St. Nicholas Ave, ICRC 10-11, New York, NY 10032. Phone: 212-851-4624; E-mail:
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Fenton H, Carlile B, Montgomery EA, Carraway H, Herman J, Sahin F, Su GH, Argani P. LKB1 Protein Expression in Human Breast Cancer. Appl Immunohistochem Mol Morphol 2006; 14:146-53. [PMID: 16785781 DOI: 10.1097/01.pai.0000176157.07908.20] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Peutz-Jeghers syndrome is caused by germline mutations in the LKB1/STK11 gene. Peutz-Jeghers syndrome is associated with an increased risk of developing intestinal and extraintestinal cancers, including pancreatic, lung, and breast carcinomas. LKB1 gene inactivation has recently been demonstrated in a subset of sporadic pancreatic and lung carcinomas. The role of the LKB1 gene in sporadic breast carcinomas remains unclear, though recent studies suggest inactivation only within papillary carcinomas. Using a commercially available polyclonal antibody that has been shown to mirror LKB1 genetic status in gastrointestinal and pulmonary carcinomas, the authors performed IHC on a large series of breast cancers using tissue microarrays (TMAs). All abnormal TMA results were confirmed using whole sections; specifically, whole sections from the donor blocks of lesions demonstrating diminished or absent LKB1 protein expression on TMA were evaluated to compare labeling of the lesion with that of the surrounding normal breast. In all cases, normal breast epithelium demonstrated strong cytoplasmic labeling (providing an internal positive control), whereas the stroma was nonreactive. Luminal cells typically labeled more strongly than myoepithelial cells. Among 70 invasive ductal carcinomas, 3 (4.3%) showed complete loss of LKB1 labeling, whereas 6 others (8.6%) showed diminished labeling. Of the eight intraductal carcinoma lesions adjacent to these invasive carcinomas, one (12.5%) showed complete loss of LKB1 labeling and one other (12.5%) showed diminished labeling; these results were identical to those of the adjacent invasive carcinomas. One of 10 (10%) hematogenous metastases of mammary carcinoma showed loss of LKB1 labeling. Nine of the 10 invasive carcinomas and both of the ductal carcinoma in situ (DCIS) cases showing loss of or diminished LKB1 expression were of high grade. In contrast, all 13 pure nonpapillary DCIS lesions, all 5 invasive lobular carcinomas and 3 accompanying lobular carcinoma in situ lesions, all 7 papillary DCIS lesions, and all 3 papillomas evaluated showed intact LKB1 labeling. Therefore, although frequent methylation of the LKB1 gene has been reported in papillary carcinomas of the breast, the authors did not find loss of protein expression in these lesions. Instead, it was found that loss of LKB1 protein expression occurs in a subset of high-grade in situ and invasive mammary carcinomas. The authors found LKB1 gene methylation in several of these invasive carcinomas. Given recent Western blot results indicating that diminished LKB1 expression in breast carcinomas correlates with shorter relapse-free survival, LKB1 IHC merits evaluation as a potential prognostic marker for breast carcinoma.
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Affiliation(s)
- Hubert Fenton
- Department of Pathology, The Johns Hopkins Medical Institutions, Baltimore, MD, USA
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Ramamurthy S, Ronnett GV. Developing a head for energy sensing: AMP-activated protein kinase as a multifunctional metabolic sensor in the brain. J Physiol 2006; 574:85-93. [PMID: 16690704 PMCID: PMC1817796 DOI: 10.1113/jphysiol.2006.110122] [Citation(s) in RCA: 132] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The 5'-adenosine monophosphate-activated protein kinase (AMPK) is a metabolic and stress sensor that has been functionally conserved throughout eukaryotic evolution. Activation of the AMPK system by various physiological or pathological stimuli that deplete cellular energy levels promotes activation of energy restorative processes and inhibits energy consumptive processes. AMPK has a prominent role not only as a peripheral sensor of energy balance, but also in the CNS as a multifunctional metabolic sensor. Recent work suggests that AMPK plays an important role in maintaining whole body energy balance by coordinating feeding behaviour through the hypothalamus in conjunction with peripheral energy expenditure. In addition, brain AMPK is activated by energy-poor conditions induced by hypoxia, starvation, and ischaemic stroke. Under these conditions, AMPK is activated as a protective response in an attempt to restore cellular homeostasis. However in vivo, it appears that the overall consequence of activation of AMPK is more complex than previously imagined, in that over-activation may be deleterious rather than neuroprotective. This review discusses recent findings that support the role of AMPK in brain as a multidimensional energy sensor and the consequences of its activation or inhibition under physiological and pathological states.
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Affiliation(s)
- Santosh Ramamurthy
- Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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von Herbay A, Arens N, Friedl W, Vogt-Moykopf I, Kayser K, Müller KM, Back W. Bronchioloalveolar carcinoma: a new cancer in Peutz-Jeghers syndrome. Lung Cancer 2005; 47:283-8. [PMID: 15639728 DOI: 10.1016/j.lungcan.2004.06.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2003] [Revised: 06/08/2004] [Accepted: 06/16/2004] [Indexed: 11/16/2022]
Abstract
Besides gastrointestinal hamartomatous polyposis and melanin spots in the skin and mucosa, patients with the Peutz-Jeghers syndrome (PJS) have repeatedly been observed with a variety of tumours, including lung cancer. Available data indicate an increased cancer risk among PJS patients, which suggests that the gene involved in PJS, STK11 on chromosome 19p13.3, may be a tumour suppressor gene. Herein, bronchioloalveolar carcinoma (BAC) of mucinous type is reported in a 22-year old male PJS patient with a novel germline frameshift insertion in exon 2 at codon 118 of the STK11 gene. Molecular studies of his BAC indicated loss of heterozygosity (LOH) in the region of STK11 on chromosome 19p13.3. This observation supports the hypothesis that STK11 is a tumour suppressor gene which is involved in the development of lung adenocarcinoma.
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Affiliation(s)
- A von Herbay
- Institute of Pathology, University of Heidelberg, Heidelberg, Germany.
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Taylor EB, Hurst D, Greenwood LJ, Lamb JD, Cline TD, Sudweeks SN, Winder WW. Endurance training increases LKB1 and MO25 protein but not AMP-activated protein kinase kinase activity in skeletal muscle. Am J Physiol Endocrinol Metab 2004; 287:E1082-9. [PMID: 15292028 DOI: 10.1152/ajpendo.00179.2004] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
LKB1 complexed with MO25 and STRAD has been identified as an AMP-activated protein kinase kinase (AMPKK). We measured relative LKB1 protein abundance and AMPKK activity in liver (LV), heart (HT), soleus (SO), red quadriceps (RQ), and white quadriceps (WQ) from sedentary and endurance-trained rats. We examined trained RQ for altered levels of MO25 protein and LKB1, STRAD, and MO25 mRNA. LKB1 protein levels normalized to HT (1 +/- 0.03) were LV (0.50 +/- 0.03), SO (0.28 +/- 0.02), RQ (0.32 +/- 0.01), and WQ (0.12 +/- 0.03). AMPKK activities in nanomoles per gram per minute were HT (79 +/- 6), LV (220 +/- 9), SO (22 +/- 2), RQ (29 +/- 2), and WQ (42 +/- 4). Training increased LKB1 protein in SO, RQ, and WQ (P < 0.05). LKB1 protein levels after training (%controls) were SO (158 +/- 17), RQ (316 +/- 17), WQ (191 +/- 27), HT (106 +/- 2), and LV (104 +/- 7). MO25 protein after training (%controls) was 595 +/- 71. Training did not affect AMPKK activity. MO25 but not LKB1 or STRAD mRNA increased with training (P < 0.05). Trained values (%controls) were MO25 (164 +/- 22), LKB1 (120 +/- 16), and STRAD (112 +/- 17). LKB1 protein content strongly correlated (r = 0.93) with citrate synthase activity in skeletal muscle (P < 0.05). In conclusion, endurance training markedly increased skeletal muscle LKB1 and MO25 protein without increasing AMPKK activity. LKB1 may be playing multiple roles in skeletal muscle adaptation to endurance training.
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Affiliation(s)
- E B Taylor
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, Utah 84602, USA
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Wei C, Amos CI, Rashid A, Sabripour M, Nations L, McGarrity TJ, Frazier ML. Correlation of staining for LKB1 and COX-2 in hamartomatous polyps and carcinomas from patients with Peutz-Jeghers syndrome. J Histochem Cytochem 2004; 51:1665-72. [PMID: 14623934 DOI: 10.1177/002215540305101210] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Germline mutations of the LKB1 gene lead to Peutz-Jeghers syndrome (PJS), which is associated with a predisposition to gastrointestinal polyposis and cancer. In this study we tested for germline mutations of LKB1 in 11 patients with PJS from nine families and analyzed the expression patterns of the LKB1 and cyclo-oxygenase-2 (COX-2) proteins in 28 Peutz-Jeghers polyps (PJPs) and five carcinomas from these patients by immunohistochemical (IHC) analysis. In eight of those families we identified seven different mutations, which consisted of two splice site mutations, two nonsense mutations, one small in-frame deletion, one frame-shift mutation, and one silent mutation. Immunostaining revealed nuclear and cytoplasmic expression of LKB1 protein in 23 PJPs and five carcinomas, nuclear expression alone in one PJP, and loss of LKB1 protein expression in four PJPs, indicating a heterogeneous LKB1 expression pattern in PJPs. Overexpression of COX-2 was detected in 23 (82%) of 28 PJPs and in all carcinomas. Despite heterogeneity in staining of LKB1 among individuals and even among samples from the same individual, we found statistically significant correlations in staining of LKB1 relative to COX-2. These results suggest that COX-2 plays a role in tumorigenesis in PJS and may therefore be considered as a potential target for PJS chemoprevention.
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Affiliation(s)
- Chongjuan Wei
- Department of Epidemiology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
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Buchet-Poyau K, Mehenni H, Radhakrishna U, Antonarakis SE. Search for the second Peutz-Jeghers syndrome locus: exclusion of the STK13, PRKCG, KLK10, and PSCD2 genes on chromosome 19 and the STK11IP gene on chromosome 2. Cytogenet Genome Res 2003; 97:171-8. [PMID: 12438709 DOI: 10.1159/000066620] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Pathogenic mutations in the serine/threonine kinase STK11 (alias LKB1) cause Peutz-Jeghers syndrome (PJS) in most affected individuals. However, in a considerable number of PJS-patients mutations cannot be detected in STK11 suggesting genetic heterogeneity. One PJS family without STK11 mutations (PJS07) has previously been described with significant evidence for linkage to a second potential PJS locus on 19q13.3-->q13.4. In this study we investigated candidate genes within markers D19S180 and D19S254, since multipoint linkage analysis yielded significant LOD scores for this region in this family. Four genes in the region (cytohesin 2: PSCD2, kallikrein 10: KLK10, protein kinase C gamma: PRKCG, and serine/threonine kinase 13: STK13) potentially involved in growth inhibitory pathways or in the pathophysiology of can- cer, were considered as candidates. We first determined the genomic structure of the PSCD2 and PRKCG genes, and performed mutation analysis of all exons and exon-intron junctions of the four genes, in the PJS07 family. No pathogenic mutation was identified in these four genes in affected individuals. A very rare polymorphism resulting in a conserved amino acid change Lys to Arg was found in PSCD2. These data provide considerable evidence for exclusion of these four genes as candidates for the second locus on 19q13.3-->q13.4 in PJS. Finally, we also excluded the recently identified STK11-interacting protein gene (STK11IP, alias LIP1) mapped in 2q36 as candidate for PJS in the PJS07 family, although this could be a good candidate in other non-STK11/LKB1 families.
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Affiliation(s)
- K Buchet-Poyau
- Division of Medical Genetics, Geneva University Medical School, and University Hospitals, Geneva, Switzerland
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Drut R, Drut RM. Testicular microlithiasis: histologic and immunohistochemical findings in 11 pediatric cases. Pediatr Dev Pathol 2002; 5:544-50. [PMID: 12239638 DOI: 10.1007/s10024-002-0015-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2002] [Accepted: 07/08/2002] [Indexed: 10/27/2022]
Abstract
Testicular microlithiasis (TM) is being recognized with increasing frequency because of the extensive use of ultrasound. TM has been linked to several pathological conditions of the testis, mainly with an increased risk for developing germ cell tumors. The pathogenesis of the microcalcospherites is unknown. We report a detailed morphologic and immunohistochemical analysis of 11 patients (age: 3 to 15 years) with TM. The microliths were related neither to the age of the children nor to the developmental stage of the testis. The microcalcospherites were PAS positive or collagen IV positive or surrounded by a collagen IV-positive band, extratubular structures consistently associated with double-layered annular tubules. Immature, smaller Sertoli cells commonly lined the inner layer of the annular tubules. Some microcalcospherites showed an interposed thin band of connective tissue cells between the concretion and the tubular basement membrane. The annular tubules seemed to result from progressive wrapping of the growing tubules around the concretions. Our findings favor the interpretation that the microliths are located outside the tubules and have been present there since very early stages of testicular development. The association of the calcospherites with Sertoli cells and annular tubules formation, like that of gonadal stromal tumor with annular tubules of the ovary and large cell-calcifying Sertoli cell tumor of the testis, favors the hypothesis that microliths may result from multifocal Sertoli cell dysfunction. Since both tumors are related to the Peutz-Jeghers syndrome, it is proposed that TM may result from the same genetic abnormalities. It is unclear how this may be related to the development of germ cell tumors. However, the presence of calcospherites in gonadoblastoma may indicate a combined Sertoli cell and germ cell derangement in the genesis of TM.
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Affiliation(s)
- Ricardo Drut
- Department of Pathology, Hospital de Niños, Superiora Sor María Ludovica, 1900 La Plata, Buenos Aires, Argentina.
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Affiliation(s)
- Lina I Yoo
- Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, Massachusetts 02115, USA
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Abstract
Hamartomatous polyposis syndromes are a group of clinically distinct but perhaps genetically related disorders in which the predominant finding is multiple hamartomatous polyps in the gastrointestinal tract. These syndromes are transmitted in an autosomal dominant fashion to offspring, but sporadic forms do exist in which the biological parents lack an identified germline mutation. Despite the nondysplastic histologic characteristics of their polyps, each hamartomatous syndrome carries an elevated risk for cancer at specific organ sites. Several genes have been identified as mutated in the germline from these syndromes, and they provide clues to the pathogenesis of the polyps and may explain some of the elevated cancer risk. Pathways involved in the hamartomatous syndromes include those of vascular endothelial growth factor, the transforming growth factor beta superfamily, and antagonizing the effects of Akt/protein kinase B.
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Affiliation(s)
- John M Carethers
- University of California, San Diego, San Diego, California 92161, USA.
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Abed AA, Günther K, Kraus C, Hohenberger W, Ballhausen WG. Mutation screening at the RNA level of the STK11/LKB1 gene in Peutz-Jeghers syndrome reveals complex splicing abnormalities and a novel mRNA isoform (STK11 c.597(insertion mark)598insIVS4). Hum Mutat 2001; 18:397-410. [PMID: 11668633 DOI: 10.1002/humu.1211] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
This study was intended to evaluate a diagnostic reverse transcriptase polymerase chain reaction based protein-truncation test for the identification of germline mutations in the serine/threonine protein kinase 11 (STK11, also designated LKB1) gene in Peutz-Jeghers syndrome (PJS). Our data exemplify that the inactivation of STK11 can be due to unusual disturbances in splicing regulation which result in truncations of the protein. However, nonsense mediated mRNA decay must be blocked with puromycin to detect shortened STK11 gene products contained in the leucocytic mRNA pool of PJS patients. Interestingly, two mutations escaped from detection by exon sequencing techniques with usual flanking PCR primers, since alterations were located right in the middle of intronic sequences. We describe a compound heterozygous PJS patient who carried two different mutations in intron 1 on separate alleles. Each of the two mutations was transmitted individually to one of his two children. In the course of our RNA based analyses we detected high level expression of a novel STK11/LKB1 mRNA variant retaining intron 4 (STK11 c.597(insertion mark)598insIVS4) in various tissues. This mRNA isoform was initiated from an alternative transcription regulatory region as revealed by primer extension analyses even in cell lines with complete methylation of the normal promoter. As a consequence of novel mutational mechanisms identified we discuss the impact of RNA based strategies for the detection of germinal STK11 mutations in PJS.
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Affiliation(s)
- A A Abed
- Department of Internal Medicine-MGO-Biocenter, University Halle-Wittenberg, Halle, Germany
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