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1.
Front Vet Sci ; 10: 1153903, 2023.
Article in English | MEDLINE | ID: mdl-37143500

ABSTRACT

Introduction: Allodynia, which can be induced by paclitaxel administration, is the presence of pain as a result of a stimulus that does not usually provoke pain. Many studies have investigated the analgesic efficacy of acupuncture, including laser acupuncture (LA) and electroacupuncture (EA). Although pain-related diseases are relatively common, few studies have analyzed the analgesic effects and mechanisms of LA combined with EA. The purpose of this study was to investigate the therapeutic effect and mechanism of manual acupuncture (MA), EA, LA, and combined therapy (LA + EA) in a paclitaxel-induced allodynia rat model. Methods: A total of 56 rats were classified into eight groups: a normal (Nor, n = 7), a control (Con, n = 7), an MA (n = 7), an EA (n = 7), a 650-nm LA (650LA, n = 7), an 830-nm LA (830LA, n = 7), a 650-nm LA combined with EA (650LA + EA, n = 7), and an 830-nm LA combined with EA group (830LA + EA, n = 7). Allodynia was induced by intraperitoneal injection of 2 mg/kg of paclitaxel every other day for a total of four times except the Nor group. Acupuncture treatments were conducted at the points of Jungwan (CV12) and Joksamni (ST36) once every other day for 6 min, for a total of nine times. Withdrawal response reaction times and force intensity of the foot were measured before the start of the experiment, after the 4th paclitaxel administration (day 8), and after the 9th and last treatment (day 15). On the 16th day, mRNA and protein expression in the spinal nerves was assessed, and a metabolome analysis of the animals' feces was performed. Results and discussion: Our analyses show that 650LA + EA treatment resulted in an upregulation of protein expression related to pain relief and nerve regeneration, whereas 830LA + EA treatment led to significant changes in metabolomes. This study demonstrates that a combination treatment of EA and LA can suppress allodynia and promote upregulation of protein expression related to nerve regeneration and is effective in changing the intestinal microbiome. Further large-scale research is required to assess the exact mechanism underlying the therapeutic effect of this combination treatment in pain-related diseases.

2.
BMC Cancer ; 22(1): 552, 2022 May 16.
Article in English | MEDLINE | ID: mdl-35578316

ABSTRACT

BACKGROUND: Scavenger receptor class A member 3 (SCARA3) is decreased in prostate cancer and myeloma. However, functions of SCARA3 in various cancers remain unclear. In this study, we tried to evaluate the functional study of SCARA3 in lung cancer. METHODS: The expression level of SCARA3 in the TCGA-database, lung cancer tissue microarray and lung cancer cells and the prognosis of lung cancer patients were measured. Lung cancer tissue microarray was analyzed pathologically using immunohistochemistry, and quantitative analysis of SCARA3 in normal lung cells and lung cancer cells was analyzed using western blot analysis. Survival curves for lung cancer patients were prepared with the Kaplan-Meier method. Migration and invasion of SCARA3 overexpressed lung cancer cells were determined using a Transwell chamber system. Proliferation of lung cancer cells was determined based on cell viability assay using cell culture in vitro and a tumorigenicity model of BALB/C nude mouse in vivo. RESULTS: The expression of SCARA3 was abnormally reduced in TCGA-database, lung tissue microarray, and various lung cancer cells. However, overexpression of SCARA3 reduced the proliferation of lung cancer. The ability of SCARA3 to inhibit cancer cell proliferation was maintained even in vivo using a mouse xenograft model. In addition, overexpression of SCARA3 reduced migration and invasion ability of lung cancer cells and induced decreases of EMT markers such as ß-catenin, vimentin, and MMP9. We aimed to prove the role of SCARA3 in the treatment of Lung cancer, and shown that the expression level of SCARA3 is important in cancer treatment using cisplatin. The enhancement of the effect of cisplatin according to SCARA3 overexpression is via the AKT and JNK pathways. CONCLUSIONS: This study confirmed an abnormal decrease in SCARA3 in lung cancer. Overexpression of SCARA3 potently inhibited tumors in lung cancer and induced apoptosis by increasing sensitivity of lung cancer to cisplatin. These results suggest that SCARA3 is a major biomarker of lung cancer and that the induction of SCARA3 overexpression can indicate an effective treatment.


Subject(s)
Lung Neoplasms , Proto-Oncogene Proteins c-akt , Animals , Cell Line, Tumor , Cell Movement , Cell Proliferation , Cisplatin/pharmacology , Epithelial-Mesenchymal Transition , Gene Expression Regulation, Neoplastic , Heat-Shock Proteins/metabolism , Humans , Lung Neoplasms/pathology , Male , Mice , Mice, Inbred BALB C , Proto-Oncogene Proteins c-akt/metabolism , Scavenger Receptors, Class A , Signal Transduction
3.
Chonnam Med J ; 56(1): 1-5, 2020 Jan.
Article in English | MEDLINE | ID: mdl-32021835

ABSTRACT

Scavenger receptors typically bind to multiple ligands on a cell surface, including endogenous and modified host-derived molecules and microbial pathogens. They promote the elimination of degraded or harmful substances such as non-self or altered-self targets through endocytosis, phagocytosis, and adhesion. Currently, scavenger receptors are subdivided into eight classes based on several variations in their sequences due to alternative splicing. Since recent studies indicate targeting scavenger receptors has been involved in cancer prognosis and carcinogenesis, we will focus on the current knowledge about the emerging role of scavenger receptor classes A to E in cancer progression.

4.
Chonnam Med J ; 55(2): 75-85, 2019 May.
Article in English | MEDLINE | ID: mdl-31161119

ABSTRACT

Psoriasis is a chronic, recurrent, heterogeneous, cutaneous inflammatory skin disease for which there is no cure. It affects approximately 7.5 million people in the United States. Currently, several biologic agents that target different molecules implicated in the pathogenic processes of psoriasis are being assessed in diverse clinical studies. However, relapse usually occurs within weeks or months, meaning there is currently no cure for psoriasis. Therefore, recent studies have discovered diverse new potential treatments for psoriasis: inhibitors of bacteria such as Staphylococcus aureus, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and neuropilin 1 (NRP1). A promising approach that has recently been described involves modifying antimicrobial peptides to develop new cutaneous anti-bacterial agents that target inflammatory skin disease induced by Staphylococcus. Increased expression of TRAIL and its death receptors DR4 and DR5 has been implicated in the pathogenesis of plaque psoriasis. In addition, TRAIL has the ability to inhibit angiogenesis by inducing endothelial cell death and by negative regulation of VEGF-induced angiogenesis via caspase-8-mediated enzymatic and non-enzymatic functions. Since NRP1 regulates angiogenesis induced by multiple signals, including VEGF, ECM and semaphorins, and also initiates proliferation of keratinocytes through NF-κB signaling pathway in involved psoriatic skin, targeting NRP1 pathways may offer numerous windows for intervention in psoriasis. In this review, we will focus on the current knowledge about the emerging role of synthetic antimicrobial peptides, TRAIL and NRP1 blocking peptides in the pathogenesis and treatment of psoriasis.

5.
Chonnam Med J ; 53(3): 173-177, 2017 Sep.
Article in English | MEDLINE | ID: mdl-29026704

ABSTRACT

Melanoma is one of the most aggressive cancers in the world and is responsible for the majority of skin cancer deaths. Recent advances in the field of immunotherapy using active, adoptive, and antigen-specific therapeutic approaches, have generated the expectation that these technologies have the potential to improve the treatment of advanced malignancies, including melanoma. Treatment options for metastatic melanoma patients have been dramatically improved by the FDA approval of new therapeutic agents including vemurafenib, dabrafenib, and sorafenib. These kinase inhibitors have the potential to work in tandem with MEK, PI3K/AKT, and mTOR to inhibit the activity of melanoma inducing BRAF mutations. This review summarizes the effects of the new therapeutic agents against melanoma and the underlying biology of these BRAF inhibitors.

6.
Biol Trace Elem Res ; 151(2): 294-300, 2013 Feb.
Article in English | MEDLINE | ID: mdl-23203814

ABSTRACT

This study investigated the anti-obesity effects of Jeju ground water containing the vanadium components S1 (8.0 ± 0.9 µg/l) and S3 (26.0 ± 2.09 µg/l) on the differentiation of 3 T3-L1 preadipocytes and obesity in mice that were fed a high-fat diet (HFD). The 3 T3-L1 preadipocyte cells were cultured and differentiated in media consisting of Jeju ground water (S1, S3) or deionized water (DW) containing dexamethasone, isobutylmethylxanthine, and insulin. Oil Red O staining showed that lipid accumulation was attenuated in adipocyte cells treated with Jeju ground water. S3 significantly decreased peroxisome-activated receptor γ and CCAAT-enhancer-binding protein α mRNA expression levels, which play major roles in the transcriptional control of adipogenesis, compared to DW. Furthermore, mRNA expression levels of targeted genes, such as adipocyte fatty acid, lipoprotein lipase, and leptin, were decreased by S3 treatment compared with the control group. In mice with HFD-induced obesity, Jeju ground water decreased HFD-induced body weight gain and reduced total cholesterol, triglyceride, and glucose levels in the plasma compared to control mice. Taken together, Jeju ground water inhibits preadipocyte differentiation and adipogenesis in obesity animal models.


Subject(s)
Anti-Obesity Agents/pharmacology , Groundwater/chemistry , Obesity/therapy , Vanadium/pharmacology , 3T3-L1 Cells , Adipocytes/cytology , Adipocytes/drug effects , Animals , Azo Compounds/chemistry , Blotting, Western , CCAAT-Enhancer-Binding Protein-alpha/chemistry , CCAAT-Enhancer-Binding Protein-alpha/genetics , Cell Differentiation/drug effects , Cells, Cultured , Culture Media/chemistry , Dexamethasone/chemistry , Diet, High-Fat/adverse effects , Fibroblasts/chemistry , Fibroblasts/cytology , Fibroblasts/drug effects , Insulin/chemistry , Lipid Metabolism , Lipoprotein Lipase/genetics , Lipoprotein Lipase/metabolism , Male , Mice , Mice, Inbred C57BL , PPAR gamma/chemistry , RNA, Messenger/analysis , Real-Time Polymerase Chain Reaction , Republic of Korea , Transcription, Genetic , Vanadium/chemistry
7.
Biochim Biophys Acta ; 1823(12): 2099-108, 2012 Dec.
Article in English | MEDLINE | ID: mdl-22982065

ABSTRACT

The catalytic subunit of DNA-dependent protein kinase (DNA-PKcs) plays an essential role in double-strand break repair by initially recognizing and binding to DNA breaks. Here, we show that DNA-PKcs interacts with the regulatory γ1 subunit of AMP-activated protein kinase (AMPK), a heterotrimeric enzyme that has been proposed to function as a "fuel gauge" to monitor changes in the energy status of cells and is controlled by the upstream kinases LKB1 and Ca²âº/calmodulin-dependent kinase kinase (CaMKK). In co-immunoprecipitation analyses, DNA-PKcs and AMPKγ1 interacted physically in DNA-PKcs-proficient M059K cells but not in DNA-PKcs-deficient M059J cells. Glucose deprivation-stimulated phosphorylation of AMPKα on Thr172 and of acetyl-CoA carboxylase (ACC), a downstream target of AMPK, is substantially reduced in M059J cells compared with M059K cells. The inhibition or down-regulation of DNA-PKcs by the DNA-PKcs inhibitors, wortmannin and Nu7441, or by DNA-PKcs siRNA caused a marked reduction in AMPK phosphorylation, AMPK activity, and ACC phosphorylation in response to glucose depletion in M059K, WI38, and IMR90 cells. In addition, DNA-DNA-PKcs(-/-) mouse embryonic fibroblasts (MEFs) exhibited decreased AMPK activation in response to glucose-free conditions. Furthermore, the knockdown of DNA-PKcs led to the suppression of AMPK (Thr172) phosphorylation in LKB1-deficient HeLa cells under glucose deprivation. Taken together, these findings support the positive regulation of AMPK activation by DNA-PKcs under glucose-deprived conditions in mammalian cells.


Subject(s)
AMP-Activated Protein Kinases/metabolism , DNA-Activated Protein Kinase/metabolism , Glioma/metabolism , Glucose/deficiency , AMP-Activated Protein Kinase Kinases , Animals , Blotting, Western , Cells, Cultured , DNA Repair/genetics , DNA-Activated Protein Kinase/antagonists & inhibitors , DNA-Activated Protein Kinase/genetics , Embryo, Mammalian/cytology , Embryo, Mammalian/drug effects , Embryo, Mammalian/metabolism , Enzyme Inhibitors/pharmacology , Fibroblasts/cytology , Fibroblasts/drug effects , Fibroblasts/metabolism , Glioma/genetics , Glioma/pathology , HeLa Cells , Humans , Immunoprecipitation , Mice , Mice, Knockout , Phosphorylation , Protein Serine-Threonine Kinases/deficiency , RNA, Small Interfering/genetics , Two-Hybrid System Techniques
8.
Cell Cycle ; 11(17): 3237-49, 2012 Sep 01.
Article in English | MEDLINE | ID: mdl-22895183

ABSTRACT

The p53R2 protein, a newly identified member of the ribonucleotide reductase family that provides nucleotides for DNA damage repair, is directly regulated by p53. We show that p53R2 is also regulated by a MEK2 (ERK kinase 2/MAP kinase kinase 2)-dependent pathway. Increased MEK1/2 phosphorylation by serum stimulation coincided with an increase in the RNR activity in U2OS and H1299 cells. The inhibition of MEK2 activity, either by treatment with a MEK inhibitor or by transfection with MEK2 siRNA, dramatically decreased the serum-stimulated RNR activity. Moreover, p53R2 siRNA, but not R2 siRNA, significantly inhibits serum-stimulated RNR activity, indicating that p53R2 is specifically regulated by a MEK2-dependent pathway. Co-immunoprecipitation analyses revealed that the MEK2 segment comprising amino acids 65-171 is critical for p53R2-MEK2 interaction, and the binding domain of MEK2 is required for MEK2-mediated increased RNR activity. Phosphorylation of MEK1/2 was greatly augmented by ionizing radiation, and RNR activity was concurrently increased. Ionizing radiation-induced RNR activity was markedly attenuated by transfection of MEK2 or p53R2 siRNA, but not R2 siRNA. These data show that MEK2 is an endogenous regulator of p53R2 and suggest that MEK2 may associate with p53R2 and upregulate its activity.


Subject(s)
Cell Cycle Proteins/metabolism , DNA Repair/genetics , Gene Expression Regulation, Enzymologic/physiology , MAP Kinase Kinase 2/metabolism , Ribonucleotide Reductases/metabolism , Antibodies, Monoclonal , Blotting, Western , Cell Line, Tumor , Gamma Rays , Genetic Vectors/genetics , Humans , Immunoprecipitation , MAP Kinase Kinase 2/physiology , Phosphorylation , RNA Interference , Scintillation Counting
9.
DNA Repair (Amst) ; 7(11): 1809-23, 2008 Nov 01.
Article in English | MEDLINE | ID: mdl-18708163

ABSTRACT

Although the accumulation of 8-oxo-dGTP in DNA is associated with apoptotic cell death and mutagenesis, little is known about the exact mechanism of hMTH1-mediated suppression of oxidative-stress-induced cell death. Therefore, we investigated the regulation of DNA-damage-related apoptosis induced by oxidative stress using control and hMTH1 knockdown cells. Small interfering RNA (siRNA) was used to suppress hMTH1 expression in p53-proficient GM00637 and H460 cells, resulting in a significant increase in apoptotic cell death after H(2)O(2) exposure; however, p53-null, hMTH1-deficient H1299 cells did not exhibit H(2)O(2)-induced apoptosis. In addition, hMTH1-deficient GM00637 and H460 cells showed increased caspase-3/7 activity, cleaved caspase-8, and Noxa expression, and gamma-H2AX formation in response to H(2)O(2). In contrast, the caspase inhibitors, p53-siRNA, and Noxa-siRNA suppressed H(2)O(2)-induced cell death. Moreover, in 8-week (long-term) cultured H460 and H1299 cells, hMTH1 suppression increased cell death, Noxa expression, and gamma-H2AX after H(2)O(2) exposure, compared to 3-week (short-term) cultured cells. These data indicate that hMTH1 plays an important role in protecting cells against H(2)O(2)-induced apoptosis via a Noxa- and caspase-3/7-mediated signaling pathway, thus conferring a survival advantage through the inhibition of oxidative-stress-induced DNA damage.


Subject(s)
Apoptosis , Caspase 3/metabolism , Caspase 7/metabolism , DNA Repair Enzymes/metabolism , Oxidative Stress , Phosphoric Monoester Hydrolases/metabolism , Proto-Oncogene Proteins c-bcl-2/metabolism , Cell Line, Tumor , Comet Assay , Humans , Hydrogen Peroxide/pharmacology , Models, Biological , Phosphorylation , Signal Transduction , Time Factors , Tumor Suppressor Protein p53/metabolism
10.
Mol Cancer Res ; 6(6): 978-89, 2008 Jun.
Article in English | MEDLINE | ID: mdl-18567801

ABSTRACT

DNA damage and mutations in the genome increase with age. To determine the potential mechanisms of senescence-dependent increases in genomic instability, we analyzed DNA mismatch repair (MMR) efficiency in young and senescent human colonic fibroblast and human embryonic lung fibroblast. It was found that MMR activity is significantly reduced in senescent cells. Western blot and immunohistochemistry analysis revealed that hMSH2 and MSH6 protein (MutS alpha complex), which is a known key component in the MMR pathway, is markedly down-regulated in senescent cells. Moreover, the addition of purified MutS alpha to extracts from senescent cells led to the restoration of MMR activity. Semiquantitative reverse transcription-PCR analysis exhibited that MSH2 mRNA level is reduced in senescent cells. In addition, a decrease in E2F transcriptional activity in senescent cells was found to be crucial for MSH2 suppression. E2F1 small interfering RNA expression reduced hMSH2 expression and MMR activity in young human primary fibroblast cells. Importantly, expression of E2F1 in quiescent cells restored the MSH2 expression as well as MMR activity, whereas E2F1-infected senescent cells exhibited no restoration of MSH2 expression and MMR activity. These results indicate that the suppression of E2F1 transcriptional activity in senescent cells lead to stable repression of MSH2, followed by a induction of MutS alpha dysfunction, which results in a reduced cellular MMR capacity in senescent cells.


Subject(s)
Cellular Senescence , DNA Mismatch Repair , DNA-Binding Proteins/metabolism , MutS Homolog 2 Protein/metabolism , Animals , Cell Line , E2F1 Transcription Factor/antagonists & inhibitors , E2F1 Transcription Factor/metabolism , Humans , Intestine, Large/metabolism , Mice , MutS Homolog 2 Protein/genetics , Promoter Regions, Genetic , RNA Interference
11.
Mol Cancer Res ; 5(10): 1083-98, 2007 Oct.
Article in English | MEDLINE | ID: mdl-17951408

ABSTRACT

Human 8-oxoguanine DNA glycosylase (hOGG1) is the main defense enzyme against mutagenic effects of cellular 7,8-dihydro-8-oxoguanine. In this study, we investigated the biological role of hOGG1 in DNA damage-related apoptosis induced by hydrogen peroxide (H(2)O(2))-derived oxidative stress. The down-regulated expression of hOGG1 by its small interfering RNA prominently triggers the H(2)O(2)-induced apoptosis in human fibroblasts GM00637 and human lung carcinoma H1299 cells via the p53-mediated apoptotic pathway. However, the apoptotic responses were specifically inhibited by hOGG1 overexpression. The p53-small interfering RNA transfection into the hOGG1-deficient GM00637 markedly inhibited the H(2)O(2)-induced activation of p53-downstream target proteins such as p21, Noxa, and caspase-3/7, which eventually resulted in the increased cell viability. Although the cell viability of hOGG1-knockdown H1299 p53 null cells was similar to that of the hOGG1 wild-type H1299, after the overexpression of p53 the hOGG1-knockdown H1299 showed the significantly decreased cell viability compared with that of the hOGG1 wild-type H1299 at the same experimental condition. Moreover, the array comparative genome hybridization analyses revealed that the hOGG1-deficient GM00637 showed more significant changes in the copy number of large regions of their chromosomes in response to H(2)O(2) treatment. Therefore, we suggest that although p53 is a major modulator of apoptosis, hOGG1 also plays a pivotal role in protecting cells against the H(2)O(2)-induced apoptosis at the upstream of the p53-dependent pathway to confer a survival advantage to human fibroblasts and human lung carcinomas through maintaining their genomic stability.


Subject(s)
Apoptosis , DNA Glycosylases/physiology , Oxidative Stress , Tumor Suppressor Protein p53/metabolism , Apoptosis/genetics , Caspase 3/metabolism , Caspase 7/metabolism , Cell Line, Tumor , Cell Survival , DNA Damage/genetics , DNA Glycosylases/genetics , Fibroblasts/enzymology , Humans , Hydrogen Peroxide/toxicity , Oxidative Stress/genetics , RNA, Small Interfering/pharmacology , Signal Transduction , Tumor Suppressor Protein p53/antagonists & inhibitors , Tumor Suppressor Protein p53/genetics
12.
Cancer Res ; 65(15): 6811-9, 2005 Aug 01.
Article in English | MEDLINE | ID: mdl-16061663

ABSTRACT

The Ras activation contributes to radioresistance, but the mechanism is unclear. This article shows that the expression of the dominant-positive H-Ras increased the Ku80 level, which is one of the key enzymes involved in repairing dsDNA breaks (DSB). After exposing the cells to ionizing radiation and analyzing them using an electrophoretic mobility shift assay and pulsed-field gel electrophoresis, it was found that activated H-Ras expression in NIH3T3 cells increases the DNA-binding activity of Ku80 and increases the DSB repair activity. Ku80 small interfering RNA expression was shown to reduce the oncogenic H-Ras-mediated increase in the DSBs and suppress the oncogenic H-Ras-mediated resistance of the cells to gamma-ray irradiation, whereas Ku80 overexpression in the NIH3T3 cells significantly increased the radioresistance. These results suggest that the Ku80 expression induced by oncogenic H-Ras seems to play an important role in protecting cells against gamma-ray irradiation.


Subject(s)
Antigens, Nuclear/biosynthesis , DNA-Binding Proteins/biosynthesis , Genes, ras/physiology , Radiation Tolerance/physiology , Animals , Antigens, Nuclear/genetics , Cell Survival/physiology , Cell Survival/radiation effects , DNA/metabolism , DNA/radiation effects , DNA Damage , DNA Repair/radiation effects , DNA-Binding Proteins/genetics , Down-Regulation , Ecdysterone/analogs & derivatives , Gamma Rays , Gene Expression Regulation , Ku Autoantigen , Mice , NIH 3T3 Cells , Oligonucleotide Array Sequence Analysis , Up-Regulation , ras Proteins/biosynthesis , ras Proteins/genetics
13.
J Biol Chem ; 280(26): 25185-95, 2005 Jul 01.
Article in English | MEDLINE | ID: mdl-15760895

ABSTRACT

Cadmium is a well known human and animal carcinogen and is a ubiquitous contaminant in the environment. Although the carcinogenic mechanism of cadmium is a multifactorial process, oxidative DNA damage is believed to be of prime importance. In particular, cadmium suppresses the capacity of cells to repair oxidative DNA damage. In this study, cadmium treatment led to a significant increase in gamma-ray-induced 8-oxoguanine (8-oxoG) formation. Western blotting and semiquantitative reverse transcription-PCR revealed that cadmium treatment caused a decrease in the expression level of human OGG1 (8-oxoguanine-DNA glycosylase-1; hOGG1) in human fibroblast GM00637 and HeLa S3 cells. In addition, the cadmium-mediated decrease in hOGG1 transcription was the result of decreased binding of the transcription factor Sp1 to the hOGG1 promoter. Finally, we show that an increase in the functional hOGG1 expression level could inhibit the cadmium-mediated increase in gamma-ray-induced 8-oxoG accumulation as well as in gamma-radiation-induced mutation frequency at the HPRT (hypoxanthine-guanine phosphoribosyltransferase) gene locus. These results suggest that cadmium attenuates removal of gamma-ray-induced 8-oxoG adducts, which in turn increases the mutation frequency, and that this effect might, at least in part, result from suppression of hOGG1 transcription via inactivation of Sp1 as a result of cadmium treatment.


Subject(s)
Cadmium/pharmacology , DNA Glycosylases/biosynthesis , Down-Regulation , Guanosine/analogs & derivatives , Sp1 Transcription Factor/metabolism , Animals , Blotting, Western , Cadmium/metabolism , Cadmium Chloride/pharmacology , Cell Line , Cell Line, Tumor , Cell Survival , DNA/metabolism , DNA Damage , Dose-Response Relationship, Drug , Dose-Response Relationship, Radiation , Drosophila , Gamma Rays , Guanosine/chemistry , HeLa Cells , Humans , Hypoxanthine Phosphoribosyltransferase/genetics , Luciferases/metabolism , Mutation , Oxygen/metabolism , Promoter Regions, Genetic , RNA, Small Interfering/metabolism , Reverse Transcriptase Polymerase Chain Reaction , Transcription, Genetic
14.
Nat Cell Biol ; 7(2): 137-47, 2005 Feb.
Article in English | MEDLINE | ID: mdl-15619620

ABSTRACT

Bcl-2 stimulates mutagenesis after the exposure of cells to DNA-damaging agents. However, the biological mechanisms of Bcl-2-mediated mutagenesis have remained largely obscure. Here we demonstrate that the Bcl-2-mediated suppression of hMSH2 expression results in a reduced cellular capacity to repair mismatches. The pathway linking Bcl-2 expression to the suppression of mismatch repair (MMR) activity involves the hypophosphorylation of pRb, and then the enhancement of the E2F-pRb complex. This is followed by a decrease in hMSH2 expression. MMR has a key role in protection against deleterious mutation accumulation and in maintaining genomic stability. Therefore, the decreased MMR activity by Bcl-2 may be an underlying mechanism for Bcl-2-promoted oncogenesis.


Subject(s)
Cell Cycle Proteins/metabolism , DNA Repair , DNA-Binding Proteins/metabolism , Proto-Oncogene Proteins c-bcl-2/physiology , Proto-Oncogene Proteins/metabolism , Transcription Factors/metabolism , Base Pair Mismatch , CDC2-CDC28 Kinases/metabolism , Cells, Cultured , Cyclin-Dependent Kinase 2 , Down-Regulation , E2F Transcription Factors , Gene Expression Regulation, Neoplastic , Humans , MutS Homolog 2 Protein , Mutagenesis , Mutation , Neoplasms/genetics , Phosphorylation , Proto-Oncogene Proteins c-bcl-2/metabolism , Retinoblastoma Protein/metabolism , Transcription, Genetic
15.
Cancer Res ; 64(14): 4849-57, 2004 Jul 15.
Article in English | MEDLINE | ID: mdl-15256455

ABSTRACT

Tumors frequently contain mutations in the ras genes, resulting in the constitutive activation of the Ras-activated signaling pathway. The activation of Ras is involved not only in tumor progression but also in the development of resistance of the tumor cells to platinum-based chemotherapeutic agents. To investigate the potential mechanisms underlying this resistance, we analyzed the effect of activated H-Ras on the expression of the nucleotide excision repair genes. Here we identified ERCC1, which is one of the key enzymes involved in nucleotide excision repair, as being markedly up-regulated by the activated H-Ras. From promoter analysis of ERCC1, an increase in the Ap1 transcriptional activity as a result of the expression of the oncogenic H-Ras was found to be crucial for this induction. In addition, ERCC1 small interfering RNA expression was shown to reduce the oncogenic H-Ras-mediated increase in the DNA repair activity as well as to suppress the oncogenic H-Ras-mediated resistance of the cells to platinum-containing chemotherapeutic agents. These results suggest that the oncogenic H-Ras-induced ERCC1, which activates the DNA repair capacity, may be involved in the protection of the cells against platinum-based anticancer agents.


Subject(s)
Antineoplastic Agents/pharmacology , DNA-Binding Proteins/biosynthesis , Endonucleases/biosynthesis , Oncogene Protein p21(ras)/physiology , Organoplatinum Compounds/pharmacology , Animals , Binding Sites , Breast Neoplasms/drug therapy , Breast Neoplasms/genetics , Breast Neoplasms/metabolism , Carboplatin/pharmacology , Cell Line, Tumor , Cisplatin/pharmacology , DNA Repair/physiology , DNA-Binding Proteins/genetics , Drug Resistance, Neoplasm , Endonucleases/genetics , Gene Expression Regulation, Neoplastic , Humans , Mice , NIH 3T3 Cells , Oncogene Protein p21(ras)/biosynthesis , Oncogene Protein p21(ras)/genetics , Oxaliplatin , Promoter Regions, Genetic , RNA, Small Interfering/biosynthesis , RNA, Small Interfering/genetics , Transcription Factor AP-1/physiology , Transcriptional Activation , Transfection , Up-Regulation
16.
J Biol Chem ; 279(33): 34138-49, 2004 Aug 13.
Article in English | MEDLINE | ID: mdl-15190073

ABSTRACT

Metallothioneins (MT) play an important biological role in preventing oxidative damage to cells. We have previously demonstrated that the efficiency of the protective effect of MT-III against the DNA degradation from oxidative damage was much higher than that of MT-I/II. As an extension of the latter investigation, this study aimed to assess the ability of MT-III to suppress 8-oxoguanine (8-oxoG), which is one of the major base lesions formed after an oxidative attack to DNA and the mutant frequency of the HPRT gene in human fibroblast GM00637 cells upon exposure to gamma-rays. We found that human MT-III expression decreased the level of 8-oxoG and mutation frequency in the gamma-irradiated cells. Using an 8-oxoguanine DNA glycosylase (OGG1)-specific siRNAs, we also found that MT-III expression resulted in the suppression of the gamma-radiation-induced 8-oxoG accumulation and mutation in the OGG1-depleted cells. Moreover, the down-regulation of MT in human neuroblastoma SKNSH cells induced by MT-specific siRNA led to a significant increase in the 8-oxoG level, after exposure to gamma-irradiation. These results suggest that under the conditions of gamma-ray oxidative stress, MT-III prevents the gamma-radiation-induced 8-oxoG accumulation and mutation in normal and hOGG1-depleted cells, and this suppression might, at least in part, contribute to the anticarcinogenic and neuroprotective role of MT-III.


Subject(s)
DNA Glycosylases/metabolism , Guanine/analogs & derivatives , Guanine/chemistry , Nerve Tissue Proteins/physiology , Antioxidants/chemistry , Antioxidants/metabolism , Antioxidants/pharmacology , Blotting, Western , Cell Line , DNA/metabolism , DNA Damage , DNA Mutational Analysis , DNA-Formamidopyrimidine Glycosylase/chemistry , Dose-Response Relationship, Radiation , Down-Regulation , Fibroblasts/metabolism , Gamma Rays , Gene Silencing , Genetic Vectors , Humans , L-Lactate Dehydrogenase/metabolism , Metallothionein 3 , Mutation , Neurons/metabolism , Oxidative Stress , Protein Isoforms , RNA, Messenger/metabolism , RNA, Small Interfering/metabolism , Reverse Transcriptase Polymerase Chain Reaction
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