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Li L, He Z, Shi Y, Sun H, Yuan B, Cai J, Chen J, Long M. Role of epigenetics in mycotoxin toxicity: a review. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2023; 100:104154. [PMID: 37209890 DOI: 10.1016/j.etap.2023.104154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 04/25/2023] [Accepted: 05/17/2023] [Indexed: 05/22/2023]
Abstract
Mycotoxins can induce cell cycle disorders, cell proliferation, oxidative stress, and apoptosis through pathways such as those associated with MAPK, JAK2/STAT3, and Bcl-w/caspase-3, and cause reproductive toxicity, immunotoxicity, and genotoxicity. Previous studies have explored the toxicity mechanism of mycotoxins from the levels of DNA, RNA, and proteins, and proved that mycotoxins have epigenetic toxicity. To explore the toxic effects and mechanisms of these changes in mycotoxins, this paper summarizes the changes in DNA methylation, non-coding RNA, RNA and histone modification induced by several common mycotoxins (zearalenone, aflatoxin B1, ochratoxin A, deoxynivalenol, T-2 toxin, etc.) based on epigenetic studies. In addition, the roles of mycotoxin-induced epigenetic toxicity in germ cell maturation, embryonic development, and carcinogenesis are highlighted. In summary, this review provides theoretical support for a better understanding of the regulatory mechanism of mycotoxin epigenotoxicity and the diagnosis and treatment of diseases.
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Affiliation(s)
- Liuliu Li
- Key Laboratory of Zoonosis of Liaoning Province, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, 110866, China; Laboratory of Ruminant Infectious Disease Prevention and Control (East), Ministry of Agriculture and Rural Affairs, P.R. China.
| | - Ziqi He
- Key Laboratory of Zoonosis of Liaoning Province, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, 110866, China; Laboratory of Ruminant Infectious Disease Prevention and Control (East), Ministry of Agriculture and Rural Affairs, P.R. China.
| | - Yang Shi
- Key Laboratory of Zoonosis of Liaoning Province, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, 110866, China; Laboratory of Ruminant Infectious Disease Prevention and Control (East), Ministry of Agriculture and Rural Affairs, P.R. China.
| | - Huiying Sun
- Key Laboratory of Zoonosis of Liaoning Province, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, 110866, China; Laboratory of Ruminant Infectious Disease Prevention and Control (East), Ministry of Agriculture and Rural Affairs, P.R. China.
| | - Bowei Yuan
- Key Laboratory of Zoonosis of Liaoning Province, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, 110866, China; Laboratory of Ruminant Infectious Disease Prevention and Control (East), Ministry of Agriculture and Rural Affairs, P.R. China.
| | - Jing Cai
- Key Laboratory of Zoonosis of Liaoning Province, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, 110866, China; Laboratory of Ruminant Infectious Disease Prevention and Control (East), Ministry of Agriculture and Rural Affairs, P.R. China.
| | - Jia Chen
- Key Laboratory of Zoonosis of Liaoning Province, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, 110866, China; Laboratory of Ruminant Infectious Disease Prevention and Control (East), Ministry of Agriculture and Rural Affairs, P.R. China.
| | - Miao Long
- Key Laboratory of Zoonosis of Liaoning Province, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, 110866, China; Laboratory of Ruminant Infectious Disease Prevention and Control (East), Ministry of Agriculture and Rural Affairs, P.R. China.
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Cheon H, Hur JK, Hwang W, Yang HJ, Son JH. Epigenetic modification of gene expression in cancer cells by terahertz demethylation. Sci Rep 2023; 13:4930. [PMID: 36967404 PMCID: PMC10040409 DOI: 10.1038/s41598-023-31828-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 03/17/2023] [Indexed: 03/29/2023] Open
Abstract
Terahertz (THz) radiation can affect the degree of DNA methylation, the spectral characteristics of which exist in the terahertz region. DNA methylation is an epigenetic modification in which a methyl (CH3) group is attached to cytosine, a nucleobase in human DNA. Appropriately controlled DNA methylation leads to proper regulation of gene expression. However, abnormal gene expression that departs from controlled genetic transcription through aberrant DNA methylation may occur in cancer or other diseases. In this study, we demonstrate the modification of gene expression in cells by THz demethylation using resonant THz radiation. Using an enzyme-linked immunosorbent assay, we observed changes in the degree of global DNA methylation in the SK-MEL-3 melanoma cell line under irradiation with 1.6-THz radiation with limited spectral bandwidth. Resonant THz radiation demethylated living melanoma cells by 19%, with no significant occurrence of apurinic/apyrimidinic sites, and the demethylation ratio was linearly proportional to the power of THz radiation. THz demethylation downregulates FOS, JUN, and CXCL8 genes, which are involved in cancer and apoptosis pathways. Our results show that THz demethylation has the potential to be a gene expression modifier with promising applications in cancer treatment.
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Affiliation(s)
- Hwayeong Cheon
- Biomedical Engineering Research Center, Asan Medical Center, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Republic of Korea
| | - Junho K Hur
- Department of Genetics, College of Medicine, Graduate School of Biomedical Sciences and Engineering, Hanyang University, Wangsimni-ro, Seongdong-gu, Seoul, 04763, Republic of Korea
| | - Woochang Hwang
- Department of Pre-Medicine, College of Medicine, Hanyang Institute of Bioscience and Biotechnology, Hanyang University, Wangsimni-ro, Seongdong-gu, Seoul, 04763, Republic of Korea
| | - Hee-Jin Yang
- Department of Neurosurgery, Seoul National University Boramae Medical Center, 20 Boramae-ro 5-gil, Dognjak-gu, Seoul, 07061, Republic of Korea.
| | - Joo-Hiuk Son
- Department of Physics, University of Seoul, 163, Seoulsiripdae-ro, Dongdaemun-gu, Seoul, 02504, Republic of Korea.
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Sun H, Zhou S, Liu Y, Lu P, Qi N, Wang G, Yang M, Huo D, Hou C. A fluorescent biosensor based on exponential amplification reaction-initiated CRISPR/Cas12a (EIC) strategy for ultrasensitive DNA methyltransferase detection. Anal Chim Acta 2023; 1239:340732. [PMID: 36628729 DOI: 10.1016/j.aca.2022.340732] [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: 10/20/2022] [Revised: 12/09/2022] [Accepted: 12/17/2022] [Indexed: 12/24/2022]
Abstract
DNA methyltransferase (DNA MTase) catalyzes the process of DNA methylation, and the aberrant DNA MTase activity is closely associated with cancer incidence and progression. Inspired by the exponential amplification reaction (EXPAR) characteristics, we developed an EXPAR-initiated CRISPR/Cas12a (EIC) strategy for sensitively detecting DNA MTase activity. A hairpin probe (HP) was designed with a palindromic sequence in the stem as substrate and NH2-modified 3' end to prevent nonspecific amplification. HP could be methylated by DNA adenine methyltransferase (Dam MTase) and then digested by DpnI to generate an oligonucleotide that can serve as an EXPAR primer. With the assistance of Nt.BstNBI nicking enzyme and Vent(exo-) polymerase, this primer bound to template and induced EXPAR. Interestingly, the product of Cycle 1 in EXPAR can function as primer to initiate Cycle 2. Both EXPAR products can further activate the collateral cleavage of CRISPR/Cas12a-crRNA, resulting in the fragmentation of fluorescence reporters and fluorescence recovery. Due to the highly efficient amplification (about 5 times signal-to-noise of SDA) and the robust trans-cleavage of CRISPR/Cas12a, the EIC system owned an extreme limit of detection (LOD) of 2 × 10-4 U/mL and a broad detection range from 2 × 10-4 to 10 U/mL for Dam MTase. In addition, this method has succeeded in inhibitor screening and evaluation, showing magnificent promise in drug discovery and cancer therapy.
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Affiliation(s)
- Human Sun
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, Bioengineering College, Chongqing University, Chongqing, 400044, PR China.
| | - Shiying Zhou
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, Bioengineering College, Chongqing University, Chongqing, 400044, PR China
| | - Yin Liu
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, Bioengineering College, Chongqing University, Chongqing, 400044, PR China
| | - Peng Lu
- Chongqing University Three Gorges Hospital, Chongqing, 404000, PR China
| | - Na Qi
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, Bioengineering College, Chongqing University, Chongqing, 400044, PR China
| | - Guixue Wang
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, Bioengineering College, Chongqing University, Chongqing, 400044, PR China
| | - Mei Yang
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, Bioengineering College, Chongqing University, Chongqing, 400044, PR China.
| | - Danqun Huo
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, Bioengineering College, Chongqing University, Chongqing, 400044, PR China; Chongqing Key Laboratory of Bio-perception & Intelligent Information Processing, School of Microelectronics and Communication Engineering, Chongqing University, Chongqing, 400044, PR China.
| | - Changjun Hou
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, Bioengineering College, Chongqing University, Chongqing, 400044, PR China; National Facility for Translational Medicine, Shanghai Jiao Tong University, Shanghai, 200240, PR China.
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Ping S, Lin W, Ming R, He Y, Yin Y, Ren Y. Toxic effects of four cardiovascular drugs on the development and epigenetics of zebrafish (Danio rerio). THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 846:157360. [PMID: 35850353 DOI: 10.1016/j.scitotenv.2022.157360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Revised: 07/02/2022] [Accepted: 07/10/2022] [Indexed: 06/15/2023]
Abstract
Due to the prevalence of cardiovascular diseases, therapeutic drugs such as atenolol (ATE), metoprolol (MET), atorvastatin (ATO), and bezafibrate (BZB) have been widely used and thus frequently detected in surface water at ng·L-1-μg·L-1 level. In this study, the developmental toxicity of these drugs (0.5 μg·L-1-500 μg·L-1) to zebrafish, an aquatic model organism, was investigated; and the epigenetic toxicity of BZB was also explored. For all four drugs, the results showed that the drugs exposure could cause sublethal toxic effects on zebrafish larvae, such as decreases in hatching rate, body length, and heart rate. ATO also induced the swelling of the eyes of larvae by 5 %-15 %. Yolk sac edema, pericardial edema, bent spine, and tail malformation were observed in larvae exposed to the drugs, and yolk sac edema was the most common malformation. In addition, the spontaneous movement and free-swimming activity could be inhibited by the drugs. Combined with RNA-seq results, the adverse development of larvae in exposure groups may be caused by the disruption of lipid and carbohydrate metabolism, and the development and function of eye and nervous system. After a 30-day uptake period, the accumulation of BZB and the decrease of global DNA methylation level were observed in the liver, kidneys, gut, gills, and brain of adult zebrafish (4-month-old) exposed to 0.5 μg·L-1 to 500 μg·L-1 BZB. The liver was the main organ for BZB accumulation and the occurrence of DNA hypomethylation. In the liver, overexpression (1.5-7.6 times) of genes related to lipid metabolism (PPARα), DNA methylation (Dnmt1), and apoptosis (p53) was also observed. The results of the current study suggest that long-term exposure to low-concentrations of cardiovascular drugs may pose significant threats to aquatic ecosystems.
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Affiliation(s)
- Senwen Ping
- School of Environment and Energy, South China University of Technology, Higher Education Mega Center, Panyu District, Guangzhou 510006, China
| | - Wenting Lin
- School of Environment and Energy, South China University of Technology, Higher Education Mega Center, Panyu District, Guangzhou 510006, China
| | - Ruiliang Ming
- Guangzhou CAS Test Technical Services Co., Ltd, Guangzhou 510650, China
| | - Yuhe He
- School of Energy and Environment, City University of Hong Kong, Hong Kong, China
| | - Yurong Yin
- School of Environment and Energy, South China University of Technology, Higher Education Mega Center, Panyu District, Guangzhou 510006, China
| | - Yuan Ren
- School of Environment and Energy, South China University of Technology, Higher Education Mega Center, Panyu District, Guangzhou 510006, China; The Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006, China; The Key Laboratory of Environmental Protection and Eco-Remediation of Guangdong Regular Higher Education Institutions, Guangzhou 510006, China.
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Abstract
Type I interferons (IFN-Is) are a very important group of cytokines that are produced by innate immune cells but also act on adaptive immune cells. IFN-Is possess antiviral, antitumor, and anti-proliferative effects, as well are associated with the initiation and maintenance of autoimmune disorders. Studies have shown that aberrantly expressed IFN-Is and/or type I IFN-inducible gene signatures in the serum or tissues of patients with autoimmune disorders are linked to their pathogenesis, clinical manifestations, and disease activity. Type I interferonopathies with mutations in genes impacting the type I IFN signaling pathway have shown symptoms and characteristics similar to those of systemic lupus erythematosus (SLE). Furthermore, both interventions in animal models and clinical trials of therapies targeting the type I IFN signaling pathway have shown efficacy in the treatment of autoimmune diseases. Our review aims to summarize the functions and targeted therapies (as well as clinical trials) of IFN-Is in both adult and pediatric autoimmune diseases, such as SLE, pediatric SLE (pSLE), rheumatoid arthritis (RA), juvenile idiopathic arthritis (JIA), juvenile dermatomyositis (JDM), Sjögren syndrome (SjS), and systemic sclerosis (SSc), discussing the potential abnormal regulation of transcription factors and epigenetic modifications and providing a potential mechanism for pathogenesis and therapeutic strategies for future clinical use.
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Donia T, Khedr S, Salim EI, Hessien M. Trichostatin A sensitizes hepatoma cells to Taxol more than 5-Aza-dC and dexamethasone. Drug Metab Pers Ther 2021; 36:299-309. [PMID: 34773731 DOI: 10.1515/dmpt-2020-0186] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Accepted: 03/16/2021] [Indexed: 11/15/2022]
Abstract
OBJECTIVES This work was designed to compare the sensitizing effects of epigenetic modifiers on cancer cells vs. that of glucocorticoids. Also, to evaluate their effects on genes involved in epigenetic changes and drug metabolism. METHODS Hepatoma cells (HepG2) were treated with the anticancer drug (Taxol), with a histone deacetylase inhibitor (Trichostatin A [TSA]), DNA methyltransferase inhibitor (5-Aza-dC) or dexamethasone (DEX). Cytotoxicity was assessed by MTT assay and the apoptosis was determined by Annexin V-FITC. The expression levels of HDAC1, HDAC3, Dnmt1, Dnmt3α, CYP1A2, CYP3A4, CYP2B6, CYP2C19 and CYP2D6 were monitored by qRT-PCR. RESULTS TSA, synergistically enhanced cells sensitivity with the anticancer effect of Taxol more than 5-Aza-dC and DEX. This was evidenced by the relative decrease in IC50 in cells cotreated with Taxol + TSA, Taxol + 5-Aza-dC or Taxol + DEX. Apoptosis was induced in 51.2, 16.9 and 41.3% of cells, respectively. In presence of Taxol, TSA induced four-fold increase in the expression of HDAC1 and downregulated Dnmt1&3α genes. CYP2D6 demonstrated progressive expression (up to 28-fold) with the increasing number of drugs. Moreover, the isoform overexpressed in cells treated with TSA + Taxol > DEX + Taxol > 5-Aza-dC + Taxol (6.4, 4.6 and 2.99, respectively). The investigated genes were clustered in two distinct subsets, where no coregulation was observed between HDAC1 and HDAC3. However, tight pairwise correlation-based cluster was seen between (CYP3A4/Dnmt3α and CYP2D6/CYP2C19). CONCLUSIONS The data reflects the sensitizing effect of acetylation modification by TSA on the responsiveness of hepatoma cells to anticancer therapy. The effect of histone deacetylase inhibition was more than hypomethylation and glucocorticoid effects. TSA exerts its role through its modulatory role on epigenetics and drugs metabolizing genes. Other modifiers (5-Aza-dC and DEX), however may adopt different mechanisms.
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Affiliation(s)
- Thoria Donia
- Division of Biochemistry, Department of Chemistry, Faculty of Science, Tanta University, Tanta, Egypt
| | - Sherien Khedr
- College of Pharmacy, Arab Academy for Science, Technology & Maritime Transport, Alexandria, Egypt
| | - Elsayed I Salim
- Department of Zoology, Faculty of Science, Tanta University, Tanta, Egypt
| | - Mohamed Hessien
- Division of Biochemistry, Department of Chemistry, Faculty of Science, Tanta University, Tanta, Egypt
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7
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Donia T, Khedr S, Salim EI, Hessien M. Trichostatin A sensitizes hepatoma cells to Taxol more than 5-Aza-dC and dexamethasone. Drug Metab Pers Ther 2021; 0:dmdi-2020-0186. [PMID: 33818027 DOI: 10.1515/dmdi-2020-0186] [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: 12/05/2020] [Accepted: 03/16/2021] [Indexed: 11/15/2022]
Abstract
OBJECTIVES This work was designed to compare the sensitizing effects of epigenetic modifiers on cancer cells vs. that of glucocorticoids. Also, to evaluate their effects on genes involved in epigenetic changes and drug metabolism. METHODS Hepatoma cells (HepG2) were treated with the anticancer drug (Taxol), with a histone deacetylase inhibitor (Trichostatin A [TSA]), DNA methyltransferase inhibitor (5-Aza-dC) or dexamethasone (DEX). Cytotoxicity was assessed by MTT assay and the apoptosis was determined by Annexin V-FITC. The expression levels of HDAC1, HDAC3, Dnmt1, Dnmt3α, CYP1A2, CYP3A4, CYP2B6, CYP2C19 and CYP2D6 were monitored by qRT-PCR. RESULTS TSA, synergistically enhanced cells sensitivity with the anticancer effect of Taxol more than 5-Aza-dC and DEX. This was evidenced by the relative decrease in IC50 in cells cotreated with Taxol + TSA, Taxol + 5-Aza-dC or Taxol + DEX. Apoptosis was induced in 51.2, 16.9 and 41.3% of cells, respectively. In presence of Taxol, TSA induced four-fold increase in the expression of HDAC1 and downregulated Dnmt1&3α genes. CYP2D6 demonstrated progressive expression (up to 28-fold) with the increasing number of drugs. Moreover, the isoform overexpressed in cells treated with TSA + Taxol > DEX + Taxol > 5-Aza-dC + Taxol (6.4, 4.6 and 2.99, respectively). The investigated genes were clustered in two distinct subsets, where no coregulation was observed between HDAC1 and HDAC3. However, tight pairwise correlation-based cluster was seen between (CYP3A4/Dnmt3α and CYP2D6/CYP2C19). CONCLUSIONS The data reflects the sensitizing effect of acetylation modification by TSA on the responsiveness of hepatoma cells to anticancer therapy. The effect of histone deacetylase inhibition was more than hypomethylation and glucocorticoid effects. TSA exerts its role through its modulatory role on epigenetics and drugs metabolizing genes. Other modifiers (5-Aza-dC and DEX), however may adopt different mechanisms.
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Affiliation(s)
- Thoria Donia
- Division of Biochemistry, Department of Chemistry, Faculty of Science, Tanta University, Tanta, Egypt
| | - Sherien Khedr
- Division of Biochemistry, Department of Chemistry, Faculty of Science, Tanta University, Tanta, Egypt
| | - Elsayed I Salim
- Department of Zoology, Faculty of Science, Tanta University, Tanta, Egypt
| | - Mohamed Hessien
- Division of Biochemistry, Department of Chemistry, Faculty of Science, Tanta University, Tanta, Egypt
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Fan X, Wang X, Zhang M, Deng H, Liu Y. Comparison detection methods for EGFR in formalin-fixed paraffin-embedded tissues of patients with NSCLC. Pathol Res Pract 2019; 216:152783. [PMID: 31859115 DOI: 10.1016/j.prp.2019.152783] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 12/02/2019] [Accepted: 12/10/2019] [Indexed: 12/29/2022]
Abstract
Epidermal growth factor receptor (EGFR) is an important gene in the development of lung cancer. Non-small cell lung cancer (NSCLC) is the most common lung cancer. In the present study, the expression of EGFR in 717 patients with NSCLC was detected by Ventana automatic immunohistochemical technique, and the samples was verified by Real-time PCR, and then the results were compared with the data acquired by next-generation sequencing technology (NGS), which is the high throughput, multiple sites for EGFR gene mutation testing. The expression of Ventana EGFR in 717 cases of NSCLC was detected by immunohistochemistry, and the positive rate was 60.70 % (435 / 717). The mutation rate of EGFR was 57.60 % (413/717). The coincidence rate of Ventana EGFR immunohistochemical assay and Real-time PCR assay reached 94.94 %, and the two had high consistency. The coincidence rate of Ventana EGFR immunohistochemical assay and NGS were high correlation. Based on these results, Ventana EGFR automatic immunohistochemical detection has high accuracy, simple operation process, low price and easy interpretation. It can be used as the preferred method for EGFR detection.
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Affiliation(s)
- Xiaojie Fan
- Department of Pathology, The Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei 050011, China
| | - Xiaoxiao Wang
- Department of Pathology, The Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei 050011, China
| | - Meng Zhang
- Department of Pathology, The Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei 050011, China
| | - Huiyan Deng
- Department of Pathology, The Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei 050011, China
| | - Yueping Liu
- Department of Pathology, The Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei 050011, China.
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Cheon H, Yang HJ, Choi M, Son JH. Effective demethylation of melanoma cells using terahertz radiation. BIOMEDICAL OPTICS EXPRESS 2019; 10:4931-4941. [PMID: 31646020 PMCID: PMC6788585 DOI: 10.1364/boe.10.004931] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 08/27/2019] [Accepted: 08/28/2019] [Indexed: 05/05/2023]
Abstract
Terahertz (THz) demethylation is a photomedical technique applied to dissociate methyl-DNA bonds and reduce global DNA methylation using resonant THz radiation. We evaluated the performance of THz demethylation and investigated the DNA damage caused by THz irradiation. The demethylation rate in M-293T DNA increased linearly with the irradiation power up to 48%. The degree of demethylation increased with exposure to THz radiation, saturating after 10 min. Although THz demethylation occurred globally, most of the demethylation occurred within the partial genes in the CpG islands. Subsequently, we performed THz demethylation of melanoma cells. The degree of methylation in the melanoma cell pellets decreased by approximately 10-15%, inducing ∼5-8 abasic sites per 105 bp; this was considerably less than the damaged DNA irradiated by the high-power infrared laser beam used for generating THz pulses. These results provide initial data for THz demethylation and demonstrate the applicability of this technique in advanced cancer cell research. THz demethylation has the potential to develop into a therapeutic procedure for cancer, similar to that involving chemical demethylating agents.
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Affiliation(s)
- Hwayeong Cheon
- Department of Physics, University of Seoul, Seoul 130-743, South Korea
| | - Hee-Jin Yang
- Department of Neurosurgery, SNU-Borame Hospital, Seoul 130-743, South Korea
| | - Moran Choi
- Department of Neurosurgery, SNU-Borame Hospital, Seoul 130-743, South Korea
| | - Joo-Hiuk Son
- Department of Physics, University of Seoul, Seoul 130-743, South Korea
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10
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Cheon H, Paik JH, Choi M, Yang HJ, Son JH. Detection and manipulation of methylation in blood cancer DNA using terahertz radiation. Sci Rep 2019; 9:6413. [PMID: 31015556 PMCID: PMC6478716 DOI: 10.1038/s41598-019-42855-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 04/10/2019] [Indexed: 12/14/2022] Open
Abstract
DNA methylation is a pivotal epigenetic modification of DNA that regulates gene expression. Abnormal regulation of gene expression is closely related to carcinogenesis, which is why the assessment of DNA methylation is a key factor in cancer research. Terahertz radiation may play an important role in active demethylation for cancer therapy because the characteristic frequency of the methylated DNA exists in the terahertz region. Here, we present a novel technique for the detection and manipulation of DNA methylation using terahertz radiation in blood cancer cell lines. We observed the degree of DNA methylation in blood cancer at the characteristic resonance of approximately 1.7 THz using terahertz time-domain spectroscopy. The terahertz results were cross-checked with global DNA methylation quantification using an enzyme-linked immunosorbent assay. We also achieved the demethylation of cancer DNA using high-power terahertz radiation at the 1.7-THz resonance. The demethylation degrees ranged from 10% to 70%, depending on the type of cancer cell line. Our results show the detection of DNA methylation based on the terahertz molecular resonance and the manipulation of global DNA methylation using high-power terahertz radiation. Terahertz radiation may have potential applications as an epigenetic inhibitor in cancer treatment, by virtue of its ability to induce DNA demethylation, similarly to decitabine.
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Affiliation(s)
- Hwayeong Cheon
- Department of Physics, University of Seoul, Seoul, 02504, Republic of Korea
| | - Jin Ho Paik
- Department of Pathology, Seoul National University Bundang Hospital, Seong-Nam, 13620, Republic of Korea
| | - Moran Choi
- Department of Neurosurgery, SMG-SNU Boramae Medical Centre, Seoul, 07061, Republic of Korea
| | - Hee-Jin Yang
- Department of Neurosurgery, SMG-SNU Boramae Medical Centre, Seoul, 07061, Republic of Korea.
| | - Joo-Hiuk Son
- Department of Physics, University of Seoul, Seoul, 02504, Republic of Korea.
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Zhang J, Chai X, He XP, Kim HJ, Yoon J, Tian H. Fluorogenic probes for disease-relevant enzymes. Chem Soc Rev 2019; 48:683-722. [PMID: 30520895 DOI: 10.1039/c7cs00907k] [Citation(s) in RCA: 357] [Impact Index Per Article: 71.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Traditional biochemical methods for enzyme detection are mainly based on antibody-based immunoassays, which lack the ability to monitor the spatiotemporal distribution and, in particular, the in situ activity of enzymes in live cells and in vivo. In this review, we comprehensively summarize recent progress that has been made in the development of small-molecule as well as material-based fluorogenic probes for sensitive detection of the activities of enzymes that are related to a number of human diseases. The principles utilized to design these probes as well as their applications are reviewed. Specific attention is given to fluorogenic probes that have been developed for analysis of the activities of enzymes including oxidases and reductases, those that act on biomacromolecules including DNAs, proteins/peptides/amino acids, carbohydrates and lipids, and those that are responsible for translational modifications. We envision that this review will serve as an ideal reference for practitioners as well as beginners in relevant research fields.
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Affiliation(s)
- Junji Zhang
- Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, Feringa Nobel Prize Scientist Joint Research Center, School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Meilong Rd., Shanghai 200237, P. R. China.
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O'Keefe CM, Giammanco D, Li S, Pisanic TR, Wang THJ. Multilayer microfluidic array for highly efficient sample loading and digital melt analysis of DNA methylation. LAB ON A CHIP 2019; 19:444-451. [PMID: 30623957 PMCID: PMC6363116 DOI: 10.1039/c8lc01189c] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Liquid biopsies contain a treasure of genetic and epigenetic biomarkers that contain information for the detection and monitoring of human disease. DNA methylation is an epigenetic modification that is critical to determining cellular phenotype and often becomes altered in many disease states. In cancer, aberrant DNA methylation contributes to carcinogenesis and can profoundly affect tumor evolution, metastatic potential, and resistance to therapeutic intervention. However, current technologies are not well-suited for quantitative assessment of DNA methylation heterogeneity, especially in challenging samples such as liquid biopsies with low DNA input and high background. We present a multilayer microfluidic device for quantitative analysis of DNA methylation by digital PCR and high resolution melt (HRM). The multilayer design facilitates high-density array digitization aimed at maximizing sample loading efficiency. The platform achieves highly parallelized digital PCR-HRM-based discrimination of rare heterogeneous DNA methylation as low as 0.0001% methylated/unmethylated molecules of a classic tumor suppressor gene, CDKN2A (p14ARF).
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Affiliation(s)
- Christine M O'Keefe
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD 21218, USA
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Wernig-Zorc S, Yadav MP, Kopparapu PK, Bemark M, Kristjansdottir HL, Andersson PO, Kanduri C, Kanduri M. Global distribution of DNA hydroxymethylation and DNA methylation in chronic lymphocytic leukemia. Epigenetics Chromatin 2019; 12:4. [PMID: 30616658 PMCID: PMC6322269 DOI: 10.1186/s13072-018-0252-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 12/23/2018] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Chronic lymphocytic leukemia (CLL) has been a good model system to understand the functional role of 5-methylcytosine (5-mC) in cancer progression. More recently, an oxidized form of 5-mC, 5-hydroxymethylcytosine (5-hmC) has gained lot of attention as a regulatory epigenetic modification with prognostic and diagnostic implications for several cancers. However, there is no global study exploring the role of 5-hydroxymethylcytosine (5-hmC) levels in CLL. Herein, using mass spectrometry and hMeDIP-sequencing, we analysed the dynamics of 5-hmC during B cell maturation and CLL pathogenesis. RESULTS We show that naïve B-cells had higher levels of 5-hmC and 5-mC compared to non-class switched and class-switched memory B-cells. We found a significant decrease in global 5-mC levels in CLL patients (n = 15) compared to naïve and memory B cells, with no changes detected between the CLL prognostic groups. On the other hand, global 5-hmC levels of CLL patients were similar to memory B cells and reduced compared to naïve B cells. Interestingly, 5-hmC levels were increased at regulatory regions such as gene-body, CpG island shores and shelves and 5-hmC distribution over the gene-body positively correlated with degree of transcriptional activity. Importantly, CLL samples showed aberrant 5-hmC and 5-mC pattern over gene-body compared to well-defined patterns in normal B-cells. Integrated analysis of 5-hmC and RNA-sequencing from CLL datasets identified three novel oncogenic drivers that could have potential roles in CLL development and progression. CONCLUSIONS Thus, our study suggests that the global loss of 5-hmC, accompanied by its significant increase at the gene regulatory regions, constitute a novel hallmark of CLL pathogenesis. Our combined analysis of 5-mC and 5-hmC sequencing provided insights into the potential role of 5-hmC in modulating gene expression changes during CLL pathogenesis.
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Affiliation(s)
- Sara Wernig-Zorc
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Mukesh Pratap Yadav
- Department of Clinical Chemistry and Transfusion Medicine, Institute of Biomedicine, Sahlgrenska University Hospital, 413 45, Gothenburg, Sweden
| | - Pradeep Kumar Kopparapu
- Department of Clinical Chemistry and Transfusion Medicine, Institute of Biomedicine, Sahlgrenska University Hospital, 413 45, Gothenburg, Sweden
| | - Mats Bemark
- Department of Microbiology and Immunology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Hallgerdur Lind Kristjansdottir
- Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, University of Gothenburg University, Gothenburg, Sweden
| | - Per-Ola Andersson
- Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, University of Gothenburg University, Gothenburg, Sweden.,Department of Internal Medicine, Södra Älvsborg Hospital, Borås, Sweden
| | - Chandrasekhar Kanduri
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Meena Kanduri
- Department of Clinical Chemistry and Transfusion Medicine, Institute of Biomedicine, Sahlgrenska University Hospital, 413 45, Gothenburg, Sweden.
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O’Keefe CM, Pisanic TR, Zec H, Overman MJ, Herman JG, Wang TH. Facile profiling of molecular heterogeneity by microfluidic digital melt. SCIENCE ADVANCES 2018; 4:eaat6459. [PMID: 30263958 PMCID: PMC6157960 DOI: 10.1126/sciadv.aat6459] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 08/14/2018] [Indexed: 05/05/2023]
Abstract
This work presents a digital microfluidic platform called HYPER-Melt (high-density profiling and enumeration by melt) for highly parallelized copy-by-copy DNA molecular profiling. HYPER-Melt provides a facile means of detecting and assessing sequence variations of thousands of individual DNA molecules through digitization in a nanowell microchip array, allowing amplification and interrogation of individual template molecules by detecting HRM fluorescence changes due to sequence-dependent denaturation. As a model application, HYPER-Melt is used here for the detection and assessment of intermolecular heterogeneity of DNA methylation within the promoters of classical tumor suppressor genes. The capabilities of this platform are validated through serial dilutions of mixed epialleles, with demonstrated detection limits as low as 1 methylated variant in 2 million unmethylated templates (0.00005%) of a classic tumor suppressor gene, CDKN2A (p14ARF). The clinical potential of the platform is demonstrated using a digital assay for NDRG4, a tumor suppressor gene that is commonly methylated in colorectal cancer, in liquid biopsies of healthy and colorectal cancer patients. Overall, the platform provides the depth of information, simplicity of use, and single-molecule sensitivity necessary for rapid assessment of intermolecular variation contributing to genetic and epigenetic heterogeneity for challenging applications in embryogenesis, carcinogenesis, and rare biomarker detection.
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Affiliation(s)
- Christine M. O’Keefe
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD 21218, USA
| | - Thomas R. Pisanic
- Johns Hopkins Institute for NanoBioTechnology, Baltimore, MD 21218, USA
| | - Helena Zec
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD 21218, USA
| | - Michael J. Overman
- Department of Gastrointestinal Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - James G. Herman
- Division of Hematology/Oncology, Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15232, USA
| | - Tza-Huei Wang
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD 21218, USA
- Johns Hopkins Institute for NanoBioTechnology, Baltimore, MD 21218, USA
- Division of Hematology/Oncology, Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15232, USA
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
- Corresponding author.
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15
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Torres-Collado AX, Knott J, Jazirehi AR. Reversal of Resistance in Targeted Therapy of Metastatic Melanoma: Lessons Learned from Vemurafenib (BRAF V600E-Specific Inhibitor). Cancers (Basel) 2018; 10:cancers10060157. [PMID: 29795041 PMCID: PMC6025215 DOI: 10.3390/cancers10060157] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 05/14/2018] [Accepted: 05/23/2018] [Indexed: 12/19/2022] Open
Abstract
Malignant melanoma is the most aggressive form of skin cancer and has a very low survival rate. Over 50% of melanomas harbor various BRAF mutations with the most common being the V600E. BRAFV600E mutation that causes constitutive activation of the MAPK pathway leading to drug-, immune-resistance, apoptosis evasion, proliferation, survival, and metastasis of melanomas. The ATP competitive BRAFV600E selective inhibitor, vemurafenib, has shown dramatic success in clinical trials; promoting tumor regression and an increase in overall survival of patients with metastatic melanoma. Regrettably, vemurafenib-resistance develops over an average of six months, which renders melanomas resistant to other therapeutic strategies. Elucidation of the underlying mechanism(s) of acquisition of vemurafenib-resistance and design of novel approaches to override resistance is the subject of intense clinical and basic research. In this review, we summarize recent developments in therapeutic approaches and clinical investigations on melanomas with BRAFV600E mutation to establish a new platform for the treatment of melanoma.
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Affiliation(s)
- Antoni Xavier Torres-Collado
- Department of Surgery, Division of Surgical Oncology, and the Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at UCLA, University of California at Los Angeles, Los Angeles, CA 90095, USA.
| | - Jeffrey Knott
- Department of Surgery, Division of Surgical Oncology, and the Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at UCLA, University of California at Los Angeles, Los Angeles, CA 90095, USA.
| | - Ali R Jazirehi
- Department of Surgery, Division of Surgical Oncology, and the Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at UCLA, University of California at Los Angeles, Los Angeles, CA 90095, USA.
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Abstract
Since every cell of a multicellular organism contains the same genome, it is intriguing to understand why genetically homogenous cells are different from each other and what controls this. Several observations indicate that DNA methylation has an essential regulatory function in mammalian development, which is to establish the correct pattern of gene expression, and that DNA methylation pattern is tightly correlated with chromatin structure. Various physiological processes are controlled by specific DNA methylation patterns including genomic imprinting, inactivation of the X chromosome, regulation of tissue-specific gene expression and repression of transposons. Moreover, aberrant methylation could confer a selective advantage to cells, leading to cancerous growth. In this review we focus on the epigenetic molecular mechanisms during normal development and discuss how DNA methylation could affect the expression of genes leading to cancer transformation.
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Affiliation(s)
- Marcella Macaluso
- Sbarro Institute for Cancer Research and Molecular Medicine, College of Science and Technology, Temple University, Philadelphia, PA, USA
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17
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Soozangar N, Sadeghi MR, Jeddi F, Somi MH, Shirmohamadi M, Samadi N. Comparison of genome‐wide analysis techniques to DNA methylation analysis in human cancer. J Cell Physiol 2017; 233:3968-3981. [DOI: 10.1002/jcp.26176] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 08/24/2017] [Indexed: 12/11/2022]
Affiliation(s)
- Narges Soozangar
- Liver and Gastrointestinal Diseases Research CenterTabriz University of Medical SciencesTabrizIran
- Department of Molecular Medicine, Faculty of Advanced Medical Sciences,Tabriz University of Medical SciencesTabrizIran
- Molecular Medicine Research CenterTabriz University of Medical SciencesTabrizIran
| | - Mohammad R. Sadeghi
- Liver and Gastrointestinal Diseases Research CenterTabriz University of Medical SciencesTabrizIran
- Department of Molecular Medicine, Faculty of Advanced Medical Sciences,Tabriz University of Medical SciencesTabrizIran
| | - Farhad Jeddi
- Liver and Gastrointestinal Diseases Research CenterTabriz University of Medical SciencesTabrizIran
- Department of Molecular Medicine, Faculty of Advanced Medical Sciences,Tabriz University of Medical SciencesTabrizIran
| | - Mohammad H. Somi
- Liver and Gastrointestinal Diseases Research CenterTabriz University of Medical SciencesTabrizIran
- Department of Molecular Medicine, Faculty of Advanced Medical Sciences,Tabriz University of Medical SciencesTabrizIran
| | - Masoud Shirmohamadi
- Liver and Gastrointestinal Diseases Research CenterTabriz University of Medical SciencesTabrizIran
| | - Nasser Samadi
- Department of Molecular Medicine, Faculty of Advanced Medical Sciences,Tabriz University of Medical SciencesTabrizIran
- Department of Biochemistry, Faculty of MedicineTabriz University of Medical SciencesTabrizIran
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18
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Gao R, Lu DF, Cheng J, Jiang Y, Jiang L, Xu JD, Qi ZM. Fiber optofluidic biosensor for the label-free detection of DNA hybridization and methylation based on an in-line tunable mode coupler. Biosens Bioelectron 2016; 86:321-329. [DOI: 10.1016/j.bios.2016.06.060] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Revised: 06/13/2016] [Accepted: 06/19/2016] [Indexed: 11/15/2022]
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19
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Zhang H, Yang Y, Dong H, Cai C. A superstructure-based electrochemical assay for signal-amplified detection of DNA methyltransferase activity. Biosens Bioelectron 2016; 86:927-932. [DOI: 10.1016/j.bios.2016.07.103] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 07/11/2016] [Accepted: 07/28/2016] [Indexed: 12/12/2022]
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20
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Fiano V, Zugna D, Grasso C, Trevisan M, Delsedime L, Molinaro L, Gillio-Tos A, Merletti F, Richiardi L. LINE-1 methylation status in prostate cancer and non-neoplastic tissue adjacent to tumor in association with mortality. Epigenetics 2016; 12:11-18. [PMID: 27892790 DOI: 10.1080/15592294.2016.1261786] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Aberrant DNA methylation seems to be associated with prostate cancer behavior. We investigated LINE-1 methylation in prostate cancer and non-neoplastic tissue adjacent to tumor (NTAT) in association with mortality from prostate cancer. We selected 157 prostate cancer patients with available NTAT from 2 cohorts of patients diagnosed between 1982-1988 and 1993-1996, followed up until 2010. An association between LINE-1 hypomethylation and prostate cancer mortality in tumor was suggested [hazard ratio per 5% decrease in LINE-1 methylation levels: 1.40, 95% confidence interval (CI): 0.95-2.01]. After stratification of the patients for Gleason score, the association was present only for those with a Gleason score of at least 8. Among these, low (<75%) vs. high (>80%) LINE-1 methylation was associated with a hazard ratio of 4.68 (95% CI: 1.03-21.34). LINE-1 methylation in the NTAT was not associated with prostate cancer mortality. Our results are consistent with the hypothesis that tumor tissue global hypomethylation may be a late event in prostate cancerogenesis and is associated with tumor progression.
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Affiliation(s)
- Valentina Fiano
- a Cancer Epidemiology Unit-CERMS , Department of Medical Sciences , University of Turin and CPO-Piemonte , Turin , Italy
| | - Daniela Zugna
- a Cancer Epidemiology Unit-CERMS , Department of Medical Sciences , University of Turin and CPO-Piemonte , Turin , Italy
| | - Chiara Grasso
- a Cancer Epidemiology Unit-CERMS , Department of Medical Sciences , University of Turin and CPO-Piemonte , Turin , Italy
| | - Morena Trevisan
- a Cancer Epidemiology Unit-CERMS , Department of Medical Sciences , University of Turin and CPO-Piemonte , Turin , Italy
| | - Luisa Delsedime
- b Division of Pathology, A.O. Città della Salute e della Scienza Hospital , Turin , Italy
| | - Luca Molinaro
- b Division of Pathology, A.O. Città della Salute e della Scienza Hospital , Turin , Italy
| | - Anna Gillio-Tos
- a Cancer Epidemiology Unit-CERMS , Department of Medical Sciences , University of Turin and CPO-Piemonte , Turin , Italy
| | - Franco Merletti
- a Cancer Epidemiology Unit-CERMS , Department of Medical Sciences , University of Turin and CPO-Piemonte , Turin , Italy
| | - Lorenzo Richiardi
- a Cancer Epidemiology Unit-CERMS , Department of Medical Sciences , University of Turin and CPO-Piemonte , Turin , Italy
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21
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Liu Z, Lei C, Deng H, Lu G, Huang Y, Yao S. Sensitive and versatile fluorescent enzymatic assay of nucleases and DNA methyltransferase based on a supercharged fluorescent protein. RSC Adv 2016. [DOI: 10.1039/c6ra02711c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The ScGFP-based platform takes advantage of the DNA length-dependent binding affinity between ScGFP and DNA for multiple DNA enzyme detection including nucleases and DNA MTase.
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Affiliation(s)
- Zhuoliang Liu
- State Key Laboratory of Chemo/Biosensing and Chemometrics
- College of Chemistry and Chemical Engineering
- Hunan University
- Changsha
- P. R. China
| | - Chunyang Lei
- State Key Laboratory of Chemo/Biosensing and Chemometrics
- College of Chemistry and Chemical Engineering
- Hunan University
- Changsha
- P. R. China
| | - Honghua Deng
- State Key Laboratory of Chemo/Biosensing and Chemometrics
- College of Chemistry and Chemical Engineering
- Hunan University
- Changsha
- P. R. China
| | - Guoyan Lu
- State Key Laboratory of Chemo/Biosensing and Chemometrics
- College of Chemistry and Chemical Engineering
- Hunan University
- Changsha
- P. R. China
| | - Yan Huang
- State Key Laboratory of Chemo/Biosensing and Chemometrics
- College of Chemistry and Chemical Engineering
- Hunan University
- Changsha
- P. R. China
| | - Shouzhuo Yao
- State Key Laboratory of Chemo/Biosensing and Chemometrics
- College of Chemistry and Chemical Engineering
- Hunan University
- Changsha
- P. R. China
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22
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Xi Q, Gao N, Yang Y, Ye W, Zhang B, Wu J, Jiang G, Zhang X. Anticancer drugs induce hypomethylation of the acetylcholinesterase promoter via a phosphorylated-p38-DNMT1-AChE pathway in apoptotic hepatocellular carcinoma cells. Int J Biochem Cell Biol 2015; 68:21-32. [DOI: 10.1016/j.biocel.2015.08.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 08/17/2015] [Accepted: 08/17/2015] [Indexed: 10/23/2022]
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Distinguishing cytosine methylation using electrochemical, label-free detection of DNA hybridization and ds-targets. Biosens Bioelectron 2014; 64:74-80. [PMID: 25194799 DOI: 10.1016/j.bios.2014.08.049] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2014] [Revised: 08/14/2014] [Accepted: 08/21/2014] [Indexed: 11/22/2022]
Abstract
In this communication we report on two important effects related to the detection of DNAs. Firstly, we investigate the sensor response to target DNA when the target is in a double stranded (ds) form and compare the response to single stranded (ss) target DNA. The importance in evaluating such an effect lies in the fact that most biological DNA targets are found in ds form. Secondly, we use synthetic ds targets to investigate the effect of DNA methylation on the sensor response. DNA methylation is known to affect functional properties of DNA and is related to a number of diseases, including various cancers. In these studies, we utilize our previously developed sensor platform, which is based on the use of a glassy carbon electrode-confined conducting polymer that is covalently modified with DNA probe sequences. The signal detection methodology we use is measuring a change in the reaction kinetics of ferro-ferricyanide redox couple at the electrode upon hybridization by means of electrical impedance spectroscopy (EIS). Additionally, EIS is utilized to study the kinetics of the hybridization of the conducting polymer-bound probe with methylated vs. non-methylated ds-DNA. Preliminary results are proving valuable as a guide to the future design of sensors for gene methylation.
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24
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Zhao Y, Chen F, Lin M, Fan C. A methylation-blocked cascade amplification strategy for label-free colorimetric detection of DNA methyltransferase activity. Biosens Bioelectron 2014; 54:565-70. [DOI: 10.1016/j.bios.2013.11.055] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Revised: 11/17/2013] [Accepted: 11/18/2013] [Indexed: 01/13/2023]
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25
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Chen F, Zhao Y. Methylation-blocked enzymatic recycling amplification for highly sensitive fluorescence sensing of DNA methyltransferase activity. Analyst 2013; 138:284-9. [DOI: 10.1039/c2an36329a] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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26
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Pulverer W, Wielscher M, Panzer-Grümayer R, Plessl T, Kriegner A, Vierlinger K, Weinhäusel A. The stem cell signature of CHH/CHG methylation is not present in 271 cancer associated 5'UTR gene regions. Biochimie 2012; 94:2345-52. [PMID: 22750649 DOI: 10.1016/j.biochi.2012.06.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Accepted: 06/21/2012] [Indexed: 01/27/2023]
Abstract
UNLABELLED Non-CpG methylation is frequently present in stem cell DNA. We investigated the value of this epigenetic modification in cancerous DNA in order to establish the implications of CHH/CHG methylation for biomarker development. Therefore we used the restriction enzymes BstNI and PspGI within a combined multiplex PCR and targeted microarray approach for the elucidation of non-CpG (CCWGG) methylation. Targeting 544 CCWGG sites in 271 5' gene regions, the CHH/CHG methylation status of the MCF7 breast cancer cell line and blood from healthy volunteers and childhood ALL was analyzed. Statistical analysis of microarray data and subsequent SYBR green based qPCR on DNA digests was applied to confirm the results from the microarray screen. RESULT/CONCLUSION The microarray experiments identified for the MCF7 cell line the genes MSH2 (p < 0.001), EREG (p < 0.001) and HSPA2 (p = 0.029) with CHH/CHG methylation, and in childhood ALL the genes HIST1H2AG (p = 0.003), PGF (p = 0.02), CPEB4 (p = 0.039) and TJP2 (p = 0.04). Validation using qPCR upon restriction digestion did not confirm the presence of CHH/CHG methylation in MCF7 DNA. In ALL samples only TJP2 was found harboring CHH/CHG methylation (p = 0.02). However, applying Bonferroni-correction for multiple testing that qPCR-result was not rated as statistically significant anymore. We concluded that non-CpG methylation in 544 CCWGG sites analyzed did not change in tumor cells. Thus any change of the CHH/CHG methylation pattern is a minor event in tumorigenesis, even if the stem cell markers OCT4, NANOG, STELLAR and GDF3 are expressed like in the MCF7 breast cancer cell line.
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Affiliation(s)
- Walter Pulverer
- AIT - Austrian Institute of Technology GmbH, Health & Environment Department, Molecular Diagnostics, Muthgasse 11/2, A-1190 Vienna, Austria.
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27
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Martinet N, Michel BY, Bertrand P, Benhida R. Small molecules DNAmethyltransferasesinhibitors. MEDCHEMCOMM 2012. [DOI: 10.1039/c1md00194a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
This review describes current knowledge concerning DNA methyltransferases (DNMT) biology and the two main classes of DNMT inhibtors.
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Affiliation(s)
- Nadine Martinet
- Laboratoire de Chimie des Molécules Bioactives et des Arômes
- UMR 6001 CNRS
- Institut de Chimie de Nice
- Université de Nice-Sophia Antipolis
- 06108 Nice Cedex 2
| | - Benoît Y. Michel
- Laboratoire de Chimie des Molécules Bioactives et des Arômes
- UMR 6001 CNRS
- Institut de Chimie de Nice
- Université de Nice-Sophia Antipolis
- 06108 Nice Cedex 2
| | - Philippe Bertrand
- Laboratory of reactivity and synthesis of natural substances
- UMR 6514 Poitiers
- France
| | - Rachid Benhida
- Laboratoire de Chimie des Molécules Bioactives et des Arômes
- UMR 6001 CNRS
- Institut de Chimie de Nice
- Université de Nice-Sophia Antipolis
- 06108 Nice Cedex 2
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28
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Sesselmann S, Söder S, Voigt R, Haag J, Grogan SP, Aigner T. DNA methylation is not responsible for p21WAF1/CIP1 down-regulation in osteoarthritic chondrocytes. Osteoarthritis Cartilage 2009; 17:507-12. [PMID: 18954998 DOI: 10.1016/j.joca.2008.09.006] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2008] [Accepted: 09/12/2008] [Indexed: 02/02/2023]
Abstract
OBJECTIVE In this study, we were interested in the overall methylation level in aged and degenerated cartilage. Also, we looked at one gene which might be involved in the re-initiation of replicative activity in osteoarthritis (OA) chondrocytes, p21(WAF1/CIP1). p21(WAF1/CIP1) was previously suggested to be down-regulated in OA chondrocytes and is known to be regulated by epigenetic modulation. METHODS Total methylation levels were analyzed by high pressure liquid chromatography (HPLC), mRNA expression of p21(WAF1/CIP1) and DNMT enzymes by real-time polymerase chain reaction. The methylation status of the p21(WAF1/CIP1)- promotor using bisulfite genomic sequencing was evaluated. RESULTS General methylation analysis of genomic DNA showed no difference in between normal and aged/OA chondrocytes. Also no difference in methylation of the promotor of the p21(WAF1/CIP1) gene was detectable, which was significantly down-regulated in OA chondrocytes. DNMT1 and DNMT3a were expressed with no significant changes of expression levels found in OA chondrocytes. CONCLUSION Cell cycle progression inhibitor p21(WAF1/CIP1) is expressed in normal and significantly down-regulated in OA articular chondrocytes, which may mediate the re-initiation of cell proliferation in OA cartilage. However, the suppression of p21(WAF1/CIP1) mRNA expression is not due to hypermethylation of its promotor. No overall changes in genome methylation levels were found in aged or OA cartilage. Interestingly, significant expression of DNA methyltransferases was found in articular chondrocytes, which supports that DNA methylation could still be a relevant mechanism of gene regulation in (osteoarthritic) chondrocytes, though not on an overall genomic level nor specifically for the regulation of the p21(WAF1/CIP1) gene.
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Affiliation(s)
- S Sesselmann
- Institute of Pathology, University Hospital Erlangen, Krankenhausstr. 12, 91054 Erlangen, Germany
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29
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Poulter MO, Du L, Weaver ICG, Palkovits M, Faludi G, Merali Z, Szyf M, Anisman H. GABAA receptor promoter hypermethylation in suicide brain: implications for the involvement of epigenetic processes. Biol Psychiatry 2008; 64:645-652. [PMID: 18639864 DOI: 10.1016/j.biopsych.2008.05.028] [Citation(s) in RCA: 195] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2007] [Revised: 05/12/2008] [Accepted: 05/29/2008] [Indexed: 01/16/2023]
Abstract
BACKGROUND Epigenetic mechanisms may be involved in the reprogramming of gene expression in response to stressful stimuli. This investigation determined whether epigenetic phenomena might similarly be associated with suicide/depression. METHODS The expression of DNA methyltransferase (DNMT) mRNA was assessed in several brain regions of individuals who had committed suicide and had been diagnosed with major depression relative to that of individuals who had died suddenly as a result of factors other than suicide. RESULTS The DNMT gene transcripts' expression was altered in several brains regions of suicides, including frontopolar cortex, amygdala, and the paraventricular nucleus of the hypothalamus. Importantly, an increase of both mRNA and protein expression was found in the frontopolar cortex. In addition, although transcript abundance of various forms of DNMT was highly correlated in normal control subjects, this coordination of DNMT isoform expression was diminished in suicide brain. Further, within the frontopolar cortex, gene-specific aberrations in DNA methylation were apparent in the gamma-aminobutyric acid (GABA)(A) receptor alpha1 subunit promoter region, the transcript of which is underexpressed in suicide/major depressive disorder (MDD) brains. Indeed, three cytosine/guanosine sites were hypermethylated relative to control subjects. Finally, we found that DNMT-3B mRNA abundance was inversely correlated to alpha1 mRNA abundance. CONCLUSIONS These data show that DNMT mRNA expression was altered in suicide brain, and this change in expression in the frontopolar cortex was associated with increased methylation of a gene whose mRNA expression has previously been shown to be reduced. These observations suggest that epigenetic mechanisms may be associated with altered gene expression in suicide/MDD.
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Affiliation(s)
- Michael O Poulter
- Molecular Brain Research Group, Robarts Research Institute, Department of Physiology and Pharmacology University of Western Ontario, London, Ontario, Canada; Institute of Neuroscience, Department of Psychology, Carleton University, Ottawa, Ontario, Canada.
| | - Lisheng Du
- Departments of Psychology and Psychiatry, University of Ottawa Institute of Mental Health Research, University of Ottawa, Ottawa, Ontario, Canada
| | - Ian C G Weaver
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
| | - Miklós Palkovits
- Neuromorphological and Neuroendocrine Research Laboratory, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary
| | - Gábor Faludi
- Department of Clinical and Theoretical Mental Health, Semmelweis University, Budapest, Hungary
| | - Zul Merali
- Departments of Psychology and Psychiatry, University of Ottawa Institute of Mental Health Research, University of Ottawa, Ottawa, Ontario, Canada
| | - Moshe Szyf
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
| | - Hymie Anisman
- Institute of Neuroscience, Department of Psychology, Carleton University, Ottawa, Ontario, Canada
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30
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Separation of purine and pyrimidine bases by ion chromatography with direct conductivity detection. J Chromatogr A 2008; 1193:104-8. [DOI: 10.1016/j.chroma.2008.04.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2007] [Revised: 04/01/2008] [Accepted: 04/08/2008] [Indexed: 11/21/2022]
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31
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Altieri F, Grillo C, Maceroni M, Chichiarelli S. DNA damage and repair: from molecular mechanisms to health implications. Antioxid Redox Signal 2008; 10:891-937. [PMID: 18205545 DOI: 10.1089/ars.2007.1830] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
DNA is subjected to several modifications, resulting from endogenous and exogenous sources. The cell has developed a network of complementary DNA-repair mechanisms, and in the human genome, >130 genes have been found to be involved. Knowledge about the basic mechanisms for DNA repair has revealed an unexpected complexity, with overlapping specificity within the same pathway, as well as extensive functional interactions between proteins involved in repair pathways. Unrepaired or improperly repaired DNA lesions have serious potential consequences for the cell, leading to genomic instability and deregulation of cellular functions. A number of disorders or syndromes, including several cancer predispositions and accelerated aging, are linked to an inherited defect in one of the DNA-repair pathways. Genomic instability, a characteristic of most human malignancies, can also arise from acquired defects in DNA repair, and the specific pathway affected is predictive of types of mutations, tumor drug sensitivity, and treatment outcome. Although DNA repair has received little attention as a determinant of drug sensitivity, emerging knowledge of mutations and polymorphisms in key human DNA-repair genes may provide a rational basis for improved strategies for therapeutic interventions on a number of tumors and degenerative disorders.
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Affiliation(s)
- Fabio Altieri
- Department of Biochemical Sciences, A. Rossi Fanelli, University La Sapienza, Rome, Italy.
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32
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Akintola AD, Crislip ZL, Catania JM, Chen G, Zimmer WE, Burghardt RC, Parrish AR. Promoter methylation is associated with the age-dependent loss of N-cadherin in the rat kidney. Am J Physiol Renal Physiol 2007; 294:F170-6. [PMID: 17959753 DOI: 10.1152/ajprenal.00285.2007] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The cadherins are cell adhesion molecules required for cellular homeostasis, and N-cadherin is the predominant cadherin expressed in proximal tubular epithelial cells in humans and rats. Our laboratory previously reported an age-dependent decrease in renal N-cadherin expression; the levels of N-cadherin mRNA and protein expression decreased in parallel, implicating a transcriptional mechanism in the age-dependent loss of expression (19). In this study, we examined the hypothesis that promoter hypermethylation underlies the loss of N-cadherin expression in aging rat kidney. We cloned the 5' flanking region of the rat N-cadherin gene and observed basic promoter activity in a 3,992-bp region localized immediately upstream of the ATG start site. Nucleotide analysis revealed 87% identity with the human N-cadherin minimal promoter region. Consistent with a role for regulation by DNA methylation, we found that a dense CpG island, which spans 1,104 bp (-1,158 to -55), flanks the rat N-cadherin gene; a similar CpG profile was found in the human N-cadherin 5' flanking region. Methylation-specific PCR analysis demonstrated that the promoter region of N-cadherin is heavily methylated in aged, but not young, rat kidney. Interestingly, the promoter is not methylated in age-matched, calorically restricted animals. In contrast, the promoter region is not methylated in either young or aged rat liver; this corresponds to the finding that aging is not associated with decreased N-cadherin expression in the liver. In addition, N-cadherin expression is markedly induced in NRK-52E cells treated with the DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine, further suggesting that methylation at CpG in the promoter region may underlie the age-dependent decrease in renal N-cadherin expression.
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Affiliation(s)
- Adebayo D Akintola
- Department of Systems Biology and Translational Medicine, College of Medicine, Texas A & M Health Science Center, College Station, TX 77843-1114, USA
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33
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Jung JK, Arora P, Pagano JS, Jang KL. Expression of DNA Methyltransferase 1 Is Activated by Hepatitis B Virus X Protein via a Regulatory Circuit Involving the p16INK4a-Cyclin D1-CDK 4/6-pRb-E2F1 Pathway. Cancer Res 2007; 67:5771-8. [PMID: 17575144 DOI: 10.1158/0008-5472.can-07-0529] [Citation(s) in RCA: 145] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
DNA methyltransferase 1 (DNMT1) is responsible for copying DNA methylation patterns to the daughter strands during DNA replication. Its expression is frequently up-regulated in human tumors, including hepatocellular carcinoma, but the mechanism of overexpression and its biological significance remain unclear. Here, we show that hepatitis B virus X protein (HBx) activates DNMT1 expression via a regulatory circuit involving the p16(INK4a)-cyclin D1-cyclin-dependent kinase (CDK) 4/6-retinoblastoma protein (pRb)-E2F1 pathway. HBx induced DNA hypermethylation of p16(INK4a) promoter to repress its expression, which subsequently led to activation of G1-CDKs, phosphorylation of pRb, activation of E2F1, and finally transcriptional activation of DNMT1. Inhibition of DNMT1 activity by either treatment with 5'-Aza-2'dC or introduction of DNMT1 small interfering RNA not only abolished the DNA methylation-mediated p16(INK4a) repression but also impaired DNMT1 expression itself, suggesting a cross-talk between DNMT1 and p16(INK4a). The up-regulation of cyclin D1 by HBx is likely to serve as an initiative impulse for the circuit because it was absolutely required for the activation of DNMT1 expression. We also observed that accumulated DNMT1 via this pathway inactivates E-cadherin expression through promoter hypermethylation. Considering that the pRb-E2F1 pathway is commonly activated in human tumors, activation of this circuit might be widespread and a potential therapeutic target.
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Affiliation(s)
- Jin Kyu Jung
- Division of Biological Sciences, College of Natural Sciences, Pusan National University, Busan, Korea
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34
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Ou JN, Torrisani J, Unterberger A, Provençal N, Shikimi K, Karimi M, Ekström TJ, Szyf M. Histone deacetylase inhibitor Trichostatin A induces global and gene-specific DNA demethylation in human cancer cell lines. Biochem Pharmacol 2007; 73:1297-307. [PMID: 17276411 DOI: 10.1016/j.bcp.2006.12.032] [Citation(s) in RCA: 142] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2006] [Revised: 12/25/2006] [Accepted: 12/27/2006] [Indexed: 11/23/2022]
Abstract
DNA methylation and chromatin structure are two modes of epigenetic control of genome function. Although it is now well established that chromatin silencing could lead to DNA methylation, the relation between chromatin activation and DNA demethylation is unclear. It was generally believed that expression of methylated genes could only be restored by demethylating agents, such as 5-aza-deoxycytidine (5-azaCdR), and that inhibition of histone deacetylation by Trichostatin A (TSA) only activates transcription of unmethylated genes. In this report, we show that increase of histone acetylation by TSA was associated with a significant decrease in global methylation. This global demethylation occurs even when DNA replication is blocked by hydroxyurea, supporting a replication-independent-mechanism of demethylation. TSA also induces histone acetylation, demethylation and expression of the methylated E-CADHERIN and RARbeta2 genes. However, the genome-wide demethylation induced by TSA does not affect all methylated tumor suppressor genes equally suggesting that induction of acetylation and demethylation by TSA shows some gene selectivity. Taken together, our data provide evidence for a reversible crosstalk between histone acetylation and DNA demethylation, which has significant implications on the use of HDAC inhibitors as therapeutic agents.
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Affiliation(s)
- Jing-Ni Ou
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
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35
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Majumder P, Pradhan SK, Devi PG, Pal S, Dasgupta D. Chromatin as a target for the DNA-binding anticancer drugs. Subcell Biochem 2007; 41:145-89. [PMID: 17484128 PMCID: PMC7121056 DOI: 10.1007/1-4020-5466-1_8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Chemotherapy has been a major approach to treat cancer. Both constituents of chromatin, chromosomal DNA and the associated chromosomal histone proteins are the molecular targets of the anticancer drugs. Small DNA binding ligands, which inhibit enzymatic processes with DNA substrate, are well known in cancer chemotherapy. These drugs inhibit the polymerase and topoisomerase activity. With the advent in the knowledge of chromatin chemistry and biology, attempts have shifted from studies of the structural basis of the association of these drugs or small ligands (with the potential of drugs) with DNA to their association with chromatin and nucleosome. These drugs often inhibit the expression of specific genes leading to a series of biochemical events. An overview will be given about the latest understanding of the molecular basis of their action. We shall restrict to those drugs, synthetic or natural, whose prime cellular targets are so far known to be chromosomal DNA.
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Affiliation(s)
- Parijat Majumder
- Biophysics Division, Saha Institute of Nuclear Physics, Block-AF, Sector-I, Bidhannagar, Kolkata-700 064, India
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36
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Schulz WA, Steinhoff C, Florl AR. Methylation of endogenous human retroelements in health and disease. Curr Top Microbiol Immunol 2006; 310:211-50. [PMID: 16909913 DOI: 10.1007/3-540-31181-5_11] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Retroelements constitute approximately 45% of the human genome. Long interspersed nuclear element (LINE) autonomous retrotransposons are predominantly represented by LINE-1, nonautonomous small interspersed nuclear elements (SINEs) are primarily represented by ALUs, and LTR retrotransposons by several families of human endogenous retroviruses (HERVs). The vast majority of LINE and HERV elements are densely methylated in normal somatic cells and contained in inactive chromatin. Methylation and chromatin structure together ensure a stable equilibrium between retroelements and their host. Hypomethylation and expression in developing germ cells opens a "window of opportunity" for retrotransposition and recombination that contribute to human evolution, but also inherited disease. In somatic cells, the presence of retroelements may be exploited to organize the genome into active and inactive regions, to separate domains and functional regions within one chromatin domain, to suppress transcriptional noise, and to regulate transcript stability. Retroelements, particularly ALUs, may also fulfill physiological roles during responses to stress and infections. Reactivation and hypomethylation of LINEs and HERVs may be important in the pathophysiology of cancer and various autoimmune diseases, contributing to chromosomal instability and chronically aberrant immune responses. The emerging insights into the pathophysiological importance of endogenous retroelements accentuate the gaps in our knowledge of how these elements are controlled in normal developing and mature cells.
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Affiliation(s)
- W A Schulz
- Urologische Klinik, Heinrich Heine Universität, Düsseldorf, Germany.
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37
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Fuso A, Scarpa S, Grandoni F, Strom R, Lucarelli M. A reassessment of semiquantitative analytical procedures for DNA methylation: comparison of bisulfite- and HpaII polymerase-chain-reaction-based methods. Anal Biochem 2006; 350:24-31. [PMID: 16445884 DOI: 10.1016/j.ab.2005.12.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2005] [Revised: 11/22/2005] [Accepted: 12/05/2005] [Indexed: 12/29/2022]
Abstract
Two techniques in particular are used to study site-specific DNA methylation: genomic sequencing after bisulfite modification and polymerase chain reaction after digestion by a methylation-sensitive endonuclease (usually HpaII). Only the former methodology assesses the methylation status of all the cytosine residues in the DNA sequence, but it is so complex and time consuming that the latter procedure, though limited to the restriction sites recognized by the endonuclease(s) used, is often preferred at least for a first analysis. In this work we investigate differences between these two techniques in the assessment of DNA methylation and offer some suggestions on how to avoid uncorrected results. Although there is substantial accordance in the results obtained using these different techniques, we observed a general overestimate for methylation levels above 30% and a general underestimate for methylation levels below this value using the HpaII/PCR technique in the study of methylation of the 5'-flanking region of the mouse myogenin gene in cultured muscle cells and mouse tissues.
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Affiliation(s)
- Andrea Fuso
- Department of Surgery P. Valdoni, University of Rome La Sapienza, Italy
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38
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Becker JC, Kirkwood JM, Agarwala SS, Dummer R, Schrama D, Hauschild A. Molecularly targeted therapy for melanoma. Cancer 2006; 107:2317-27. [PMID: 17039502 DOI: 10.1002/cncr.22273] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Effective therapy for melanoma remains an unmet goal, with most traditional therapies representing inadequate trade-offs among the several goals of specificity, efficacy, and toxicity. Targeted molecular therapeutics are tailored to genetic abnormalities that are associated with tumor progression. Modulation of aberrant signaling pathways in cancer cells has the potential to provide more effective and potentially nontoxic therapy for a broad range of cancers, including melanoma. Among the possible targets in melanoma are the Ras-MAPK and PI3K/AKT signal transduction pathways, the proteasome, histone deacetylases, methyltransferases, and melanoma-induced angiogenesis.
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Affiliation(s)
- Jürgen C Becker
- Department of Dermatology, Julius Maximilians University, Würzburg, Germany
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39
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Ghen MJ, Roshan R, Roshan RO, Blyweiss DJ, Corso N, Khalili B, Zenga WT. Potential clinical applications using stem cells derived from human umbilical cord blood. Reprod Biomed Online 2006; 13:562-72. [PMID: 17007681 DOI: 10.1016/s1472-6483(10)60646-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
There is an abundance of clinical applications using human umbilical cord blood (HUCB) as a source for stem cell populations. Other than haematopoietic progenitors, there are mesenchymal, endothelial stem cells and neuronal precursors, in varying quantities, that are found in human umbilical cord blood. These may be useful in diseases such as immune deficiency and autoimmune disorders. Considering issues of safety, availability, transplant methodology, rejection and side effects, it is contended that a therapeutic stem cell transplant, utilizing stem cells from HUCB, provides a reliable repository of early precursor cells that can be useful in a great number of diverse conditions. Drawbacks of relatively smaller quantities of mononucleated cells in one unit of cord blood can be mitigated by in-vitro expansion procedures, improved in-vivo signalling, and augmentation of the cellular milieu, while simultaneously choosing the appropriate transplantation site and technique for introduction of the stem cell graft.
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Affiliation(s)
- M J Ghen
- Eden Laboratories Ltd, Frederick House, Frederick Street, PO Box SS-19392, Nassau, The Bahamas.
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40
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Malins DC, Gilman NK, Green VM, Wheeler TM, Barker EA, Anderson KM. A cancer DNA phenotype in healthy prostates, conserved in tumors and adjacent normal cells, implies a relationship to carcinogenesis. Proc Natl Acad Sci U S A 2005; 102:19093-6. [PMID: 16361440 PMCID: PMC1323211 DOI: 10.1073/pnas.0509630102] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A cancer DNA phenotype, identical to the DNA structure of tumors, has been identified in the prostate glands of certain healthy men over 55 years of age. We now show that the same DNA signature exists in normal tissues adjacent to tumors. This finding implies that the phenotype is maintained in normal prostate cells from its inception through tumor development. The presence of the phenotype in tumors, adjacent normal cells, and in the normal prostate cells of certain older men suggests that it is a potentially critical factor in tumor development and may serve as an early biomarker for cancer risk assessment. Intervention to inhibit the development of the phenotype in healthy men, or to eliminate it once formed, may suppress or even prevent tumor formation.
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Affiliation(s)
- Donald C Malins
- Biochemical Oncology Program, Pacific Northwest Research Institute, 720 Broadway, Seattle, WA 98122, USA.
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41
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Meaney MJ, Szyf M. Environmental programming of stress responses through DNA methylation: life at the interface between a dynamic environment and a fixed genome. DIALOGUES IN CLINICAL NEUROSCIENCE 2005. [PMID: 16262207 PMCID: PMC3181727 DOI: 10.31887/dcns.2005.7.2/mmeaney] [Citation(s) in RCA: 499] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Early experience permanently alters behavior and physiology. These effects are, in part, mediated by sustained alterations in gene expression in selected brain regions. The critical question concerns the mechanism of these environmental “programming” effects. We examine this issue with an animal model that studies the consequences of variations in mother-infant interactions on the development of individual differences in behavioral and endocrine responses to stress in adulthood. Increased levels of pup licking/grooming by rat mothers in the first week of life alter DNA structure at a glucocorticoid receptor gene promoter in the hippocampus of the offspring. Differences in the DNA methylation pattern between the offspring of high- and low-lickinglgrooming mothers emerge over the first week of life; they are reversed with cross-fostering; they persist into adulthood; and they are associated with altered histone acetylation and transcription factor (nerve growth factor-induced clone A [NGFIA]) binding to the glucocorticoid receptor promoter. DNA methylation alters glucocorticoid receptor expression through modifications of chromatin structure. Pharmacological reversal of the effects on chromatin structure completely eliminates the effects of maternal care on glucocorticoid receptor expression and hypothalamic-pituitary-adrenal (HPA) responses to stress, thus suggesting a causal relation between the maternally induced, epigenetic modification of the glucocorticoid receptor gene and the effects on stress responses in the offspring. These findings demonstrate that the structural modifications of the DNA can be established through environmental programming and that, in spite of the inherent stability of this epigenomic marker, it is dynamic and potentially reversible.
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Affiliation(s)
- Michael J Meaney
- McGill Program for the Study of Behavior, Genes and Environment, Department of Pharmacology, McGill University, Douglas Hospital Research Centre, Montreal, Quebec, Canada.
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Jeong KS, Lee S. Estimating the total mouse DNA methylation according to the B1 repetitive elements. Biochem Biophys Res Commun 2005; 335:1211-6. [PMID: 16115613 DOI: 10.1016/j.bbrc.2005.08.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2005] [Accepted: 08/02/2005] [Indexed: 12/31/2022]
Abstract
Measuring the degree of methylation of the B1 element in mouse may represent the global DNA methylation status because about 30,000 copies of the B1 element are randomly dispersed in the total mouse genome. Six CpG dinucleotides are located within each 163 bp size of B1 element, and each CpG dinucleotide was partially methylated. We quantitated the DNA methylation of the B1 repetitive elements by performing PCR for the methylation specific PCR (MSP) and also by the pyrosequencing. Each CpG dinucleotide was methylated at an average of 9% in the mouse genome by the pyrosequencing and MSP. Especially, we checked whether CpG methylation of the B1 element could respond to a treatment of the DNA methylation inhibitor, 5-azacytidine (5-AzaC). Consequently, the calibration graph resulting from measuring the relative CpG methylation percentage of the B1 element is linearly decreased with the increasing amount of 5-AzaC (up to 50 ng/ml concentration) in the NIH3T3 cells with a standard deviation of only 1.73% between three independent assays. Our methods can be applied to the routine analysis of the global DNA methylation changes in mouse in vivo and in vitro in pharmaceuticals and basic epigenetic research with efforts being less labor-intensive.
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Affiliation(s)
- Kyoung-Sin Jeong
- Functional Genomics Lab, CHA Research Institute, Bundang Campus, College of Medicine, Pochon CHA University, 222 Yatap-Dong, Bundang-Gu, Sungnam-Si, Kyunggi-Do, 463-836, Republic of Korea
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43
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Hoffmann MJ, Schulz WA. Causes and consequences of DNA hypomethylation in human cancer. Biochem Cell Biol 2005; 83:296-321. [PMID: 15959557 DOI: 10.1139/o05-036] [Citation(s) in RCA: 172] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
While specific genes are hypermethylated in the genome of cancer cells, overall methylcytosine content is often decreased as a consequence of hypomethylation affecting many repetitive sequences. Hypomethylation is also observed at a number of single-copy genes. While global hypomethylation is highly prevalent across all cancer types, it often displays considerable specificity with regard to tumor type, tumor stage, and sequences affected. Following an overview of hypomethylation alterations in various cancers, this review focuses on 3 hypotheses. First, hypomethylation at a single-copy gene may occur as a 2-step process, in which selection for gene function follows upon random hypo methylation. In this fashion, hypomethylation facilitates the adaptation of cancer cells to the ever-changing tumor tissue microenvironment, particularly during metastasis. Second, the development of global hypomethylation is intimately linked to chromatin restructuring and nuclear disorganization in cancer cells, reflected in a large number of changes in histone-modifying enzymes and other chromatin regulators. Third, DNA hypomethylation may occur at least partly as a consequence of cell cycle deregulation disturbing the coordination between DNA replication and activity of DNA methyltransferases. Finally, because of their relation to tumor progression and metastasis, DNA hypomethylation markers may be particularly useful to classify cancer and predict their clinical course.
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44
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Van den Eynden GG, Van Laere SJ, Van der Auwera I, Merajver SD, Van Marck EA, van Dam P, Vermeulen PB, Dirix LY, van Golen KL. Overexpression of caveolin-1 and -2 in cell lines and in human samples of inflammatory breast cancer. Breast Cancer Res Treat 2005; 95:219-28. [PMID: 16244790 DOI: 10.1007/s10549-005-9002-1] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2005] [Indexed: 12/23/2022]
Abstract
PURPOSE Inflammatory breast cancer (IBC) is the most aggressive form of locally advanced breast cancer (LABC). The IBC phenotype is characterized by an infiltrative growth pattern, increased (lymph)angiogenesis and the propensity to invade dermal lymphatics. In pancreatic cancer, interactions between caveolin-1 and RhoC GTPase, a key molecule in causing the IBC phenotype, regulate tumour cell motility and invasion. In this study we sought to investigate the role of caveolin-1 and -2 in IBC cell lines and in human IBC samples. EXPERIMENTAL DESIGN Differential methylation techniques identified the methylation status of the caveolin-1 and -2 promoters in human mammary epithelial cells (HMECs) and the SUM149 cell line. In cell line experiments, caveolin-1 and -2 mRNA and protein expression were compared in HMECs, MCF10A, the SUM102 non-IBC cell lines and 2 IBC cell lines (SUM149 and SUM190). Furthermore, caveolin-1 and -2 mRNA and protein expression were compared in human IBC and non-IBC samples using cDNA microarray, real-time qRT-PCR and immunohistochemistry. Results were correlated with RhoC protein expression data. RESULTS In the SUM149 cell line, the caveolin-1 and -2 promoter sites were hypomethylated. A significantly increased expression of caveolin-1 and -2, both at the mRNA and protein level was found in IBC cell lines and in human samples of IBC: caveolin-1 and -2 mRNA were respectively 1.7 (p = 0.02) and 2.2 (p = 0.03) fold more expressed in IBC compared to non IBC and at the protein level, 41.4% of IBC specimens expressed either caveolin-1 or -2, compared to 15.6% of non-IBC specimens (p = 0.03). Furthermore a correlation was found between RhoC protein expression and caveolin-1 (p = 0.1) or caveolin-2 (p = 0.09) or either caveolin-1 or -2 protein expression (p = 0.04). CONCLUSIONS Although considered a tumour suppressor in breast cancer, we demonstrated overexpression of caveolin-1 and -2 in IBC cell lines and in human samples of IBC, most likely due to hypomethylation of their respective promoters. These results confirm the distinct molecular signature of IBC. Our data further suggest interaction between RhoC GTPase and the caveolins in IBC.
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MESH Headings
- Adult
- Aged
- Aged, 80 and over
- Biomarkers, Tumor/genetics
- Biomarkers, Tumor/metabolism
- Breast Neoplasms/genetics
- Breast Neoplasms/metabolism
- Breast Neoplasms/pathology
- Carcinoma, Ductal, Breast/genetics
- Carcinoma, Ductal, Breast/metabolism
- Carcinoma, Ductal, Breast/pathology
- Carcinoma, Lobular/genetics
- Carcinoma, Lobular/metabolism
- Carcinoma, Lobular/pathology
- Caveolin 1/genetics
- Caveolin 1/metabolism
- Caveolin 2/genetics
- Caveolin 2/metabolism
- Cell Line, Tumor
- DNA Methylation
- Female
- Gene Expression Profiling
- Gene Expression Regulation, Neoplastic
- Humans
- Immunoenzyme Techniques
- Middle Aged
- Neoplasm Staging
- Oligonucleotide Array Sequence Analysis
- RNA, Messenger/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Up-Regulation
- rho GTP-Binding Proteins/genetics
- rho GTP-Binding Proteins/metabolism
- rhoC GTP-Binding Protein
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Affiliation(s)
- Gert G Van den Eynden
- Translational Cancer Research Group Antwerp, Lab Pathology, University of Antwerp/University Hospital Antwerp, Edegem, Belgium
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45
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Richardson A, Kaye SB. Drug resistance in ovarian cancer: The emerging importance of gene transcription and spatio-temporal regulation of resistance. Drug Resist Updat 2005; 8:311-21. [PMID: 16233989 DOI: 10.1016/j.drup.2005.09.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2005] [Revised: 09/12/2005] [Accepted: 09/19/2005] [Indexed: 12/18/2022]
Abstract
Resistance to carboplatin plus paclitaxel, one of the most active drug combinations in ovarian cancer, is the major barrier to the successful long-term treatment of this disease. Understanding the mechanisms involved is a first step towards rational strategies to overcome drug resistance and is an area of intense research effort. Recent work has identified several gene families which appear to contribute to the evolution of drug resistance and which are involved in regulating DNA damage, apoptosis and survival signalling. These genes may be co-ordinately regulated as part of a gene expression program that confers drug resistance through multiple pathways. The subcellular localisation of the gene products and their kinetic regulation following exposure to chemotherapeutic agents may also play a part in the development of drug resistance. This provides a more complex paradigm for drug resistance in which the steady-state expression of a single gene may not be predictive of response to therapy. Nevertheless, the identification of critical genes, most relevant to the development of clinical drug resistance, is now feasible through microarray analysis of tumour samples, and strategies aimed at the circumvention of resistance can be developed using these data.
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Affiliation(s)
- Alan Richardson
- The Institute of Cancer Research, 15 Cotswold Road, Sutton SM2 5NG, UK.
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46
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Wada K, Arima H, Tsutsumi T, Hirayama F, Uekama K. Enhancing effects of galactosylated dendrimer/alpha-cyclodextrin conjugates on gene transfer efficiency. Biol Pharm Bull 2005; 28:500-5. [PMID: 15744077 DOI: 10.1248/bpb.28.500] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To improve in vitro gene transfer efficiency and/or achieve cell-specific gene delivery of polyamidoamine (PAMAM) starburst dendrimer (generation 2, G2) conjugate with alpha-cyclodextrin (alpha-CDE conjugate (G2)), we prepared alpha-CDE conjugate bearing galactose (Gal-alpha-CDE conjugates) with the various degrees of substitution of the galactose moiety (DSG) as a novel non-viral vector. The agarose gel electrophoretic studies revealed that Gal-alpha-CDE conjugates formed complexes with plasmid DNA (pDNA) and protected the degradation of pDNA by DNase I, but these effects impaired as the DSG value increased. Dendrimer and alpha-CDE conjugate exerted pDNA condensation through the complexation, but Gal-alpha-CDE conjugates did not. Gal-alpha-CDE conjugate (DSG 4) was found to have much higher gene transfer activity than dendrimer, alpha-CDE conjugate and Gal-alpha-CDE conjugates (DSG 8, 15) in HepG2, NIH3T3 and A549 cells, which are independent of the expression of the asialoglycoprotein receptor. Transfection activity of Gal-alpha-CDE conjugate (DSG 4) was insensitive to the existence of competitors (asialofetuin and galactose) and serum. In addition, no cytotoxicity after transfection of the complex of pDNA with Gal-alpha-CDE conjugate (DSG 4) was observed. These results suggest the potential use of Gal-alpha-CDE conjugate (DSG 4) as a non-viral vector in various cells.
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Affiliation(s)
- Koki Wada
- Graduate School of Pharmaceutical Sciences, Kumamoto University, Oe-honmachi, Kumamoto, Japan
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47
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Abstract
Epigenetic processes affect three stages of germline development, namely (1) specification and formation of primordial germ cells and their germline derivatives through lineage-specific epigenetic modifications, in the same manner as other embryonic lineages are formed, (2) a largely genome-wide erasure and re-establishment of germline-specific epigenetic modifications that only occurs in the embryonic primordial germ cell lineage, followed by re-establishment of sex-specific patterns during gametogenesis, and (3) differential epigenetic modifications to the mature male and female gamete genomes shortly after fertilisation. This review will detail current knowledge of these three processes both at the genome-wide level and at specific imprinted loci. The consequences of epigenetic perturbation are discussed and new in vitro models which may allow further understanding of a difficult developmental period to study, especially in the human, are highlighted.
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Affiliation(s)
- Cinzia Allegrucci
- Division of Obstetrics and Gynaecology and Institute of Genetics, University of Nottingham, Queens Medical Centre, Nottingham NG7 2UH, UK
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48
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Novotny L, Szekeres T. Recent developments in cancer chemotherapy oriented towards new targets. Expert Opin Ther Targets 2005; 9:343-57. [PMID: 15934920 DOI: 10.1517/14728222.9.2.343] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Malignant diseases are one of the major causes of death in the western world. Patients are treated by surgery, radiation and chemotherapy. Chemotherapeutic treatment is used to decrease the tumour burden and to eliminate malignant cells. However, in most cases, resistance against chemotherapy develops. Therefore, there is a permanent need for new additional treatment strategies and chemotherapeutic combination regimens. In the present review article, the authors try to highlight the most promising approaches and summarise a selection of potential targets and compounds which might become alternative treatment options against malignant diseases. Due to the high number of scientific articles and the rapid developments in the area of cancer research, the authors can only mention a few selected targets and treatment options; however, the review focuses on new and notably important targets and compounds.
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Affiliation(s)
- Ladislav Novotny
- Kuwait University, Faculty of Pharmacy, PO Box 24923, Safat 1311, Kuwait.
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49
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Szyf M, Pakneshan P, Rabbani SA. DNA methylation and breast cancer. Biochem Pharmacol 2004; 68:1187-97. [PMID: 15313416 DOI: 10.1016/j.bcp.2004.04.030] [Citation(s) in RCA: 144] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2004] [Accepted: 04/21/2004] [Indexed: 12/31/2022]
Abstract
DNA methylation and chromatin structure patterns are tightly linked components of the epigenome, which regulate gene expression programming. Two contradictory changes in DNA methylation patterns are observed in breast cancer; regional hypermethylation of specific genes and global hypomethylation. It is proposed here that independent mechanisms are responsible for these alterations in DNA methylation patterns and that these alterations deregulate two different processes in breast cancer. Regional hypermethylation is brought about by specific regional changes in chromatin structure, whereas global demethylation is caused by a general increase in demethylation activity. Hypermethylation silences growth regulatory genes resulting in uncontrolled growth whereas hypomethylation leads to activation of genes required for metastasis. DNA methylation inhibitors activate silenced tumor suppressor genes resulting in arrest of tumor growth and are now being tested as candidate anticancer drugs. Demethylation inhibitors are proposed here to be potential novel candidate antimetastatic agents, which would bring about methylation and silencing of metastatic genes. Future therapeutic application of either methylation or demethylation inhibitors in cancer therapy would require understanding of the relative role of these processes in the evolution of cancer.
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Affiliation(s)
- Moshe Szyf
- Department of Pharmacology and Therapeutics, McGill University, 3655 Sir William Osier Promenade, Montreal, Canada PQ H3G 1Y6.
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50
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Szyf M, Pakneshan P, Rabbani SA. DNA demethylation and cancer: therapeutic implications. Cancer Lett 2004; 211:133-43. [PMID: 15219937 DOI: 10.1016/j.canlet.2004.04.009] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2004] [Accepted: 04/20/2004] [Indexed: 01/12/2023]
Abstract
The epigenome, which is comprised of chromatin and its associated proteins and the patterns of covalent modification of DNA by methylation, sets up and maintains gene expression programs. A hallmark of cancer is a paradoxical aberration of DNA methylation patterns, a global loss of DNA methylation, that coexists with regional hypermethylation of certain genes. The hypermethylation of tumor-suppressor genes has attracted significant attention recently and DNA methylation inhibitors are being tested as potential anticancer agents. However, emerging data suggests that hypomethylation plays a role in activating genes required for metastasis and invasion. It is proposed here that hypermethylation and hypomethylation in cancer are independent processes, which target different programs at different stages in tumorigenesis. Understanding the relative roles of hypomethylation and hypermethylation in cancer has clear implications on the therapeutic use of agents targeting the DNA methylation machinery, which are discussed in this review.
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Affiliation(s)
- Moshe Szyf
- Department of Pharmacology and Therapeutics, McGill University, 3655 Sir William Osler Promenade, Montreal, Que., Canada PQ H3G 1Y6.
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