• Title/Summary/Keyword: DNA Repair

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Study on characteristics of cancer in the elderly (노인 종양의 특성에 대한 연구)

  • Ha, Jae-Won;Cho, Jung-Hyo;Son, Chang-Kyu;Lee, Yeon-Weol;Yoo, Hwa-Seung;Cho, Chong-Kwan
    • THE JOURNAL OF KOREAN ORIENTAL ONCOLOGY
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    • v.9 no.1
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    • pp.99-108
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    • 2003
  • Recently, the proportion of the population older has increased rapidly. As the aged population is increasing, the prevalence of malignancy rises with age, too. We believe that the potential benefits of approach to cancer care in the elderly are self-evident. In order to investigate the characteristics of cancer in the elderly, we reviewed literature related with the biology of the aged with cancer. The elderly undergo age-related changes in their physiology which may result in altered tolerance to disease and to the requirements of the management of illness. The possible reasons for the increased prevalence of cancer in the elderly are a longer potential duration of exposure to carcinogens, a reduced ability of repair DNA and reduced host defences against malignancy. In general, cancer patients in the elderly have a shorter survival. Because it is impossible to offer the active treatment of cancer in the elderly. Also, they have the problems that the psychosocial change and reduce of physiological function such as absorption, metabolism and excretion. We hope that other groups will further research cancer in the elderly in future.

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Suppression of Ku80 Correlates with Radiosensitivity and Telomere Shortening in the U2OS Telomerase-negative Osteosarcoma Cell Line

  • Hu, Liu;Wu, Qin-Qin;Wang, Wen-Bo;Jiang, Huan-Gang;Yang, Lei;Liu, Yu;Yu, Hai-Jun;Xie, Cong-Hua;Zhou, Yun-Feng;Zhou, Fu-Xiang
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.2
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    • pp.795-799
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    • 2013
  • Ku70/80 heterodimer is a central element in the nonhomologous end joining (NHEJ) DNA repair pathway, Ku80 playing a key role in regulating the multiple functions of Ku proteins. It has been found that the Ku80 protein located at telomeres is a major contributor to radiosensitivity in some telomerase positive human cancer cells. However, in ALT human osteosarcoma cells, the precise function in radiosensitivity and telomere maintenance is still unknown. The aim of this study was to investigate the effects of Ku80 depletion in the U2OS ALT cell line cell line. Suppression of Ku80 expression was performed using a vector-based shRNA and stable Ku80 knockdown in cells was verified by Western blotting. U2OS cells treated with shRNA-Ku80 showed lower radiobiological parameters (D0, Dq and SF2) in clonogenic assays. Furthermore, shRNA-Ku80 vector transfected cells displayed shortening of the telomere length and showed less expression of TRF2 protein. These results demonstrated that down-regulation of Ku80 can sensitize ALT cells U2OS to radiation, and this radiosensitization is related to telomere length shortening.

Antioxidant Activity and Its Mechanism of Chelidonium majus Extract (백굴채 추출물의 항산화 활성과 기전)

  • Heo, Jee In;Kim, Jeong Hyeon;Lee, Jeong Min;Lim, Soon Sung;Kim, Sung Chan;Park, Jae Bong;Kim, Jae Bong;Lee, Jae Yong
    • Korean Journal of Medicinal Crop Science
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    • v.21 no.2
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    • pp.136-141
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    • 2013
  • Chelidonium majus (CM) contains several isoquinoline alkaloids that have been reported to have various biological activities such as anti-inflammatory, antimicrobial, antioxidant, immune-modulatory, and antitumoral. It has been reported that the extract of CM had an antioxidant potential, however the mechanism has not been verified. In this study, we found that CM extract activated FOXO3a. FOXO3a is a transcription factor that involved in various biological processes such as cell cycle arrest, apoptosis, DNA repair, and ROS detoxification. Transcriptional activities of FOXO3a were regulated by post-translational modifications including phosphorylation, acetylation, and ubiquitination. Protein level of FOXO3a was increased by CM extract. Promoter activities of FOXO-transcriptional target genes such as MnSOD, p27 and GADD45 were activated by CM extract in a dose dependent manner. In addition, protein level of MnSOD, major antioxidant enzyme, was increased by CM extract. Thereby ROS level was decreased by CM in old HEF cells. These results suggest that CM extract has an antioxidant activity through FOXO activation.

Identification and Functional Analysis of RelA/SpoT Homolog (RSH) Genes in Deinococcus radiodurans

  • Wang, Jinhui;Tian, Ye;Zhou, Zhengfu;Zhang, Liwen;Zhang, Wei;Lin, Min;Chen, Ming
    • Journal of Microbiology and Biotechnology
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    • v.26 no.12
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    • pp.2106-2115
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    • 2016
  • To identify the global effects of (p)ppGpp in the gram-positive bacterium Deinococcus radiodurans, which exhibits remarkable resistance to radiation and other stresses, RelA/SpoT homolog (RSHs) mutants were constructed by direct deletion mutagenesis. The results showed that RelA has both synthesis and hydrolysis domains of (p)ppGpp, whereas RelQ only synthesizes (p)ppGpp in D. radiodurans. The growth assay for mutants and complementation analysis revealed that deletion of relA and relQ sensitized the cells to $H_2O_2$, heat shock, and amino acid limitation. Comparative proteomic analysis revealed that the bifunctional RelA is involved in DNA repair, molecular chaperone functions, transcription, the tricarboxylic acid cycle, and metabolism, suggesting that relA maintains the cellular (p)ppGpp levels and plays a crucial role in oxidative resistance in D. radiodurans. The D. radiodurans relA and relQ genes are responsible for (p)ppGpp synthesis/hydrolysis and (p)ppGpp hydrolysis, respectively. (p)ppGpp integrates a general stress response with a targeted re-programming of gene regulation to allow bacteria to respond appropriately towards heat shock, oxidative stress, and starvation. This is the first identification of RelA and RelQ involvement in response to oxidative, heat shock, and starvation stresses in D. radiodurans, which further elucidates the remarkable resistance of this bacterium to stresses.

RNA Polymerase II Inhibitor, ${\alpha}$-Amanitin, Affects Gene Expression for Gap Junctions and Metabolic Capabilities of Cumulus Cells, but Not Oocyte, during In Vitro Mouse Oocyte Maturation

  • Park, Min-Woo;Lee, Hyun-Seo;Kim, Eun-Young;Lee, Kyung-Ah
    • Development and Reproduction
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    • v.17 no.1
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    • pp.63-72
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    • 2013
  • A specific inhibitor of RNA polymerase II, ${\alpha}$-amanitin is broadly used to block transcriptional activities in cells. Previous studies showed that ${\alpha}$-amanitin affects in vitro maturation of cumulus-oocyte-complex (COC). In this study, we evaluated the target of ${\alpha}$-amanitin, and whether it affects oocytes or cumulus cells (CCs), or both. We treated ${\alpha}$-amanitin with different time period during in vitro culture of denuded oocytes (DOs) or COCs in comparison, and observed the changes in morphology and maturation status. Although DOs did not show any change in morphology and maturation rates with ${\alpha}$-amanitin treatment, oocytes from COCs were arrested at metaphase I (MI) stage and CCs were more scattered than control groups. To discover causes of meiotic arrest and scattering of CCs, we focused on changes of cumulus expansion, gap junctions, and cellular metabolism which to be the important factors for the successful in vitro maturation of COCs. Expression of genes for cumulus expansion markers (Ptx3, Has2, and Tnfaip6) and gap junctional proteins (Gja1, Gja4, and Gjc1) decreased in ${\alpha}$-amanitin-treated CCs. However, these changes were not observed in oocytes. In addition, expression of genes related to metabolism (Prps1, Rpe, Rpia, Taldo1, and Tkt) decreased in ${\alpha}$-amanitin-treated CCs but not in oocytes. Therefore, we concluded that the transcriptional activities of CCs for supporting suitable transcripts, especially for its metabolic activities and formation of gap junctions among CCs as well as with oocytes, are important for oocytes maturation in COCs.

Technical Aspects and Difficulties in the Management of Head and Neck Cutaneous Malignancies in Xeroderma Pigmentosum

  • Sibar, Serhat;Findikcioglu, Kemal;Erdal, Ayhan Isik;Barut, Ismail;Ozmen, Selahattin
    • Archives of Plastic Surgery
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    • v.43 no.4
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    • pp.344-351
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    • 2016
  • Background Xeroderma pigmentosum (XP) is an autosomal recessive disorder characterized by xerosis, ultraviolet light sensitivity, and cutaneous dyspigmentation. Due to defects in their DNA repair mechanism, genetic mutations and carcinogenesis inevitably occurs in almost all patients. In these patients, reconstruction of cutaneous malignancies in the head and neck area is associated with some challenges such as likelihood of recurrence and an aggressive clinical course. The aim of this study is to discuss the therapeutic options and challenges commonly seen during the course of treatment. Methods Between 2005 and 2015, 11 XP patients with head and neck cutaneous malignancies were included in this study. Demographic data and treatment options of the patients were evaluated. Results The mean age of the patients was 32 years (range, 10-43) (4 males, 7 females). The most common tumor type and location were squamous cell carcinoma (6 patients) and the orbital region (4 patients), respectively. Free tissue transfer was the most commonly performed surgical intervention (4 patients). The average number of surgical procedures was 5.5 (range, 1-25). Six patients were siblings with each other, 5 patients had local recurrences, and one patient was lost to follow-up. Conclusions Although genetic components of the disease have been elucidated, there is no definitive treatment algorithm. Early surgical intervention and close follow-up are the gold standard modalities due to the tendency toward rapid tumor growth and possible recurrence. Treatment must be individualized for each patient. In addition, the psychological aspect of the disease is an important issue for both patients and families.

Anti-Cancer Effect of IN-2001 in T47D Human Breast Cancer

  • Joung, Ki-Eun;Min, Kyung-Nan;Kim, Dae-Kee;Sheen, Yhun-Yhong
    • Biomolecules & Therapeutics
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    • v.20 no.1
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    • pp.81-88
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    • 2012
  • Histone deacetylases (HDACs) are enzymes involved in the remodelling of chromatin, and have a key role in the epigenetic regulation of gene expression. Histone deacetylase (HDAC) inhibitors are emerging as an exciting new class of potential anti-cancer agents. In recent years, a number of structurally diverse HDAC inhibitors have been identifi ed and these HDAC inhibitors induce growth arrest, differentiation and/or apoptosis of cancer cells in vitro and in vivo. However, the underlying molecular mechanisms remain unclear. This study aimed at investigating the anti-tumor activity of various HDAC inhibitors, IN-2001, using T47D human breast cancer cells. Moreover, the possible mechanism by which HDAC inhibitors exhibit anti-tumor activity was also explored. In estrogen receptor positive T47D cells, IN-2001, HDAC inhibitor showed anti-proliferative effects in dose-and time-dependent manner. In T47D human breast cancer cells showed anti-tumor activity of IN-2001 and the growth inhibitory effects of IN-2001 were related to the cell cycle arrest and induction of apoptosis. Flow cytometry studies revealed that IN-2001 showed accumulation of cells at $G_2$/M phase. At the same time, IN-2001 treatment time-dependently increased sub-$G_1$ population, representing apoptotic cells. IN-2001-mediated cell cycle arrest was associated with induction of cdk inhibitor expression. In T47D cells, IN-2001 as well as other HDAC inhibitors treatment significantly increased $p21^{WAF1}$ and $p27^{KIP1}$ expression. In addition, thymidylate synthase, an essential enzyme for DNA replication and repair, was down-regulated by IN-2001 and other HDAC inhibitors in the T47D human breast cancer cells. In summary, IN-2001 with a higher potency than other HDAC inhibitors induced growth inhibition, cell cycle arrest, and eventual apoptosis in human breast cancer possibly through modulation of cell cycle and apoptosis regulatory proteins, such as cdk inhibitors, cyclins, and thymidylate synthase.

Effects of Flavonol Derivatives on the Micronudei Formation by N-methyl-N'-nitro-N-nitrosoguanidine and the Enhancement of Bleomycin-induced Chromosome Aberration by N-methyl-N'-nitro-N-nitrosoguanidine

  • Heo, Moon-Young;Kwon, Chang-Ho;Sohn, Dong-Hun;Lee, Su-Jun;Kim, Sung-Wan;Kim, Jung-Han;William W. Au
    • Archives of Pharmacal Research
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    • v.16 no.3
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    • pp.196-204
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    • 1993
  • Flavonol derivatives were tested for their anticlastogenic effect against induction of micronuclei by n-methyl-n'-nitor-n-nitorsoguanidine(MNNG), and against induction of chromosome aberration by bleomycin or MNNG.belomycin. For micronudeus assay, each flavonol derivative (0, 0.001, 0.01, 0.1, 1, 10 and 100 mg/kg) was administered orally twice with 24 h interval, together with intraperitioneally administered MNNG(150 mg/kg). The result showed that msot flavonol derivatives tested were effective in suppresing the frequencies of micronude induced by MNNG. For chromosome aberration assy, each flavonol derivative (0, 0.1, 1, 10m and 100 mg/kg)was administered to mice orally in vivo, and then mice were sacrificed and spleen lymphocyte cultures were made. Bleomycin $(3\;\mu$g/ml) was treated to the mouse spleen hymphocyte cultures at 24 h after con A initiation. There wre nomarked decrease tendencies in chromosome aberration unless all doses of galangin and some doses of several flavonol derivatives tested. In the another experiment, we have evaluated the effect of flavonol derivatives on the enhancement of bleomycin-induced chromsome aberration by MNNG. Most of flavonol derivtives reduced the incidence of chromosome aberration induced by in vitro treatment of bleomycin followed by in vivo treatment of MNNG. Galangin particulary showed a dose-dependent decrease tendency. Other flavonol derivative showed slightly suggest that most of flavonol derivatives may be capable of protecting the inhibition of suggest that most of flavonol derivatives may be capable of protecting the inhibition of DNA-repair by MNNG. Our data indicate clearly that flavonol derivatives can suppress MNNG-induced genotoxicity such as an induction of MNPCEs. Therfore, our results could suggest that flavonol derivtives may be useful as a chemopreventive agent of MNNG.

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Current Pharmacogenetic Approach for Oxaliplatin-induced Peripheral Neuropathy among Patients with Colorectal Cancer: A Systematic Review (대장암 환자의 옥살리플라틴(oxaliplatin) 유도 말초신경병증에 대한 약물유전학적 접근: 체계적 문헌고찰)

  • Ahn, Soojung;Choi, Soyoung;Jung, Hye Jeong;Chu, Sang Hui
    • Journal of Korean Biological Nursing Science
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    • v.20 no.2
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    • pp.55-66
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    • 2018
  • Purpose: Peripheral neuropathy is common among colorectal cancer (CRC) patients who undergo oxaliplatin-based (OXL) chemotherapy. A pharmacogenetic approach can be used to identify patients at high-risk of developing severe neuropathy. This type of approach can also help clinicians determine the best treatment option and prevent severe neurotoxicity. The purpose of this study is to investigate the evidence of pharmacogenetic markers for OXL-induced peripheral neuropathy (OXIPN) in patients with CRC. Methods: A systematic literature search was conducted using the following databases up to December 2017: Pubmed, EMBASE, and CINAHL. We reviewed the genetic risk factors for OXIPN in observational studies and randomized controlled clinical trials (RCTs). All processes were performed independently by two reviewers. Results: Sixteen studies published in English between 2006 and 2017 were included in this review. A genome-wide association approach was used in one study and various candidate genes were tested, based on their functions (e.g., DNA damage or repair, ion channels, anti-oxidants, and nerve growth etc.). The genes associated with incidence or severity of OXIPN were ABCG2, GSTP1, XRCC1, TAC1, and ERCC1. Conclusion: This study highlighted the need and the importance of conducting pharmacogenetic studies to generate evidence of personalized OXIPN symptoms management. Additional studies are warranted to accelerate the tailored interventions used for OXIPN in patients with CRC (NRF-2014R1A1A3054386).

Correction: Ethanolic Extract of Marsdenia condurango Ameliorates Benzo[a]pyrene-induced Lung Cancer of Rats -Condurango Ameliorates BaP-induced Lung Cancer in Rats-

  • Sikdar, Sourav;Mukherjee, Avinaba;Khuda-Bukhsh, Anisur Rahman
    • Journal of Pharmacopuncture
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    • v.18 no.2
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    • pp.86-87
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    • 2015
  • Objectives: Condurango is widely used in various systems of complementary and alternative medicine (CAM) against oesophageal and stomach ailments including certain types of cancer. However, until now no systematic study has been conducted to verify its efficacy and dose with proper experimental support. Therefore, we examined if ethanolic extract of Condurango could ameliorate benzo[a]pyrene (BaP)-induced lung cancer in rats in vivo to validate its use as a traditional medicine. Methods: After one month of scheduled BaP feeding (50 mg/kg body-weight), lung cancer developed after four months. BaP-intoxicated rats were then treated with Condurango (0.06 mL) twice daily starting at the end of the four months for an additional one, two and three months, respectively. Effects of Condurango were evaluated by analyzing lung histology, reactive oxygen species (ROS) and antioxidant biomarkers, DNA-fragmentation, RT-PCR (Reverese Transcriptase-Polymerase Chain Reaction), ELISA (Enzyme linked immunosorbent assay) and western blot of several apoptotic signalling markers and comparing the results against those obtained for controls. Results: A histological study revealed gradual progress in lung tissue-repair activity in Condurango-fed cancer-bearing rats, showing gradual tissue recovery after three months of drug administration. Condurango has the capacity to generate ROS, which may contribute to a reduction in anti-oxidative activity and to an induction of oxidative stress-mediated cancer-cell death. Condurango-activated pro-apoptotic genes (Bax, caspase-3, caspase-9, p53, cytochrome-c, apaf-1, ICAD and PARP) and down-regulated antiapoptotic-Bcl-2 expression were noted both at mRNA and protein levels. Studies on caspase-3 activation and PARP cleavage by western blot analysis revealed that Condurango induced apoptosis through a caspase-3-dependent pathway. Conclusions: The anticancer efficacy of an ethanolic extract of Condurango for treating BaP-induced lung cancer in rats lends support for its use in various traditional systems of medicine.