• Journal of Radiation Protection and Research
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• 제26권4호
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• pp.385-392
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• 2001

환경독성물질이나 생물 위해 요소의 환경내 준위가 일정 수준 이상일 경우 환경재해가 유발될 수 있다. 이온화 방사선의 산업적 의료적 이용이 점차 증가하고 있으며 병해충을 막기 위한 살충제 사용의 점진적 증가로 인해 이들에 의한 재해 가능성을 배제할 수 없다. 이들 재해 요인들에 의한 인체 위해도를 비교하기 위하여 단세포 겔 전기영동법 (SCGE)을 이용하여 사람 림프구 DNA 손상에 미치는 방사선과 살충제의 영향을 각각 평가하였다. 각기 다른 농도로 살충제를 10분간 처리한 림프구에 대한 SCGE 분석을 실시하였고 또한 $0{\sim}2.0Gy$의 방사선을 조사한 림프구에 대한 SCGE 분석을 실시하여 DNA 손상도를 평가하였다. DNA 손상도는 감마선에 대해서 뚜렷한 선량-반응 관계를 나타내었을 뿐 아니라 살충제에 대해서도 명확한 농도-반응 관계를 나타내었다. 파라치온은 농업권장 사용농도인 $1mg{\ell}^{-1}$에서도 림프구에 대해 강한 유전독성을 나타내는데 이러한 유전독성은 0.1 Gy의 감마선에 의해 유발되는 DNA 손상에 상응하며 $2mg{\ell}^{-1}$의 파라치온은 임상적 증상을 야기할 가능성이 있는 전신 외부피폭 방사선량인 0.25 Gy에 상응하는 세포손상을 유발하였다. 이와 같은 연구를 통해 방사선과 살충제의 인체 위해도를 비교할 수 있는 실험적 자료와 환경재해 예방에 필요한 생물정보를 제공할 수 있다.

• Asian Pacific Journal of Cancer Prevention
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• 제15권24호
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• pp.10985-10989
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• 2015

Background: The capability for DNA double-strand breaks (DSBs) repair is crucial for inherent radiosensitivity of tumor and normal cells. We have investigated the clinicopathologic significance of DNA repair gene expression in nasopharyngeal (NP) carcinoma. Materials and Methods: A total of 65 NP cancer patients who received radiotherapy were included. The immunopositivity to Ku 70, DNA-PKcs, MRN, RAD50, XRCC4, and LIG4 were examined in all tumor tissues. Results: The patients comprised 42 males and 23 females, with a median age of 56 years (range, 18-84). The expression levels of RAD50 (0,+1,+2,+3) were 27.7%, 32.3%, 21.5%, and 18.5%. LIG4 (${\pm}$) were 43.1% and 56.9% respectively. The 5-year OS rate of patients with LIG4 (${\pm}$) were 90% and 67.9%, respectively (p=0.035). The 5-year TTP rate of patients with LIG4 (${\pm}$) were 75.9%, 55.5%, respectively (P=0.039). Conclusions: Our results suggest the possibility of predicting the radiosensitivity of NP cancer by performing immunohistochemical analysis of LIG4.

• Toxicological Research
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• 제24권3호
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• pp.175-182
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• 2008

DNA-dependent protein kinase(DNA-PK) is involved in joining DNA double-strand breaks induced by ionizing radiation or V(D)J recombination and is activated by DNA ends and composed of a DNA binding subunit, Ku, and a catalytic subunit, DNA-PKcs. It has been suggested that DNA-PK might be $2^{nd}$ upstream kinase for protein kinase B(PKB). In this report, we showed that Ser473 phosphorylation in the hydrophobic-motif of PKB is blocked in DNA-PK knockout mouse embryonic fibroblast cells(MEFs) following insulin stimulation, while there is no effect on Ser473 phosphorylation in DNA-PK wild type MEF cells. The observation is further confirmed in human glioblastoma cells expressing a mutant form of DNA-PK(M059J) and a wild-type of DNA-PK(M059K), indicating that DNA-PK is indeed important for PKB activation. Furthermore, the treatment of cells with doxorubicin, DNA-damage inducing agent, leads to PKB phosphorylation on Ser473 in control MEF cells while there is no response in DNA-PK knockout MEF cells. Together, these results proposed that DNA-PK has a potential role in insulin signaling as well as DNA-repair signaling pathway.

• 환경생물
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• 제28권2호
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• pp.101-107
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• 2010

Metal ions are essential to life. However, some metals such as mercury are harmful, even when present at trace amounts. Toxicity of mercury arises mainly from its oxidizing properties. Ionizing radiation (IR) is an active tool for destruction of cancer cells and diagnosis of diseases, etc. IR induces DNA double strand breaks in the nucleus, In addition, it causes lipid peroxidation, ceramide generation, and protein oxidation in the membrane, cytoplasm and nucleus. Yeasts have been a commonly used material in biological research. In yeasts, the physiological response to changing environmental conditions is controlled by the cell types. Growth rate, mutation and environmental conditions affect cell size and shape distributions. In this work, the effect of IR and mercury chloride (II) on the morphology of yeast cells were investigated. Saccharomyces cerevisiae cells were treated with IR, mercury chloride (II) and IR combined with mercury chloride (II). Non-treated cells were used as a control group. Morphological changes were observed by a scanning electron microscope (SEM). The half-lethal condition from the previous experimental results was used to the IR combined with mercury. Yeast cells were exposed to 400 and 800 Gy at dose rates of 400Gy $hr^{-1}$ or 800 Gy $hr^{-1}$, respectively. Yeast cells were treated with 0.05 to 0.15 mM mercury chloride (II). Oxidative stress can damage cellular membranes through a lipidic peroxidation. This effect was detected in this work, after treatment of IR and mercury chloride (II). The cell morphology was modified more at high doses of IR and high concentrations of mercury chloride(II). IR and mercury chloride (II) were of the oxidative stress. Cell morphology was modified differently according to the way of oxidative stress treatment. Moreover, morphological changes in the cell membrane were more observable in the frequently stress treated cells than the temporarily stress treated cells.

• Asian Pacific Journal of Cancer Prevention
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• 제17권2호
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• pp.815-821
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• 2016

Background: Development of chronic myeloid leukemia (CML) involves formation of double strand breaks (DSBs) which are initially sensed by the ataxia telangiectasia mutated (ATM) signal kinase to induce a DNA damage response (DDR). Mutations or single nucleotide polymorphisms in ATM gene are known to influence the signaling capacity resulting in susceptibility to certain genetic diseases such as cancers. Materials and Methods: In the present study, we have analyzed -5144A>T (rs228589) and C4138T (rs3092856) polymorphisms of theATM gene through polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in 925 subjects (476 CML cases and 449 controls). Results: The A allele of -5144A>T polymorphism and T allele of C4138T polymorphism which were known to be influencing ATM signaling capacity are significantly associated with enhanced risk for CML independently and also in combination (evident from the haplotype and diplotype analyses). Significant elevation in the frequencies of both the risk alleles among high risk groups under European Treatment and Outcome Study (EUTOS) score suggests the possible role of these polymorphisms in predicting the prognosis of CML patients. Conclusions: This study provides the first evidence of association of functional ATM gene polymorphisms with the increased risk of CML development as well as progression.

• Asian Pacific Journal of Cancer Prevention
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• 제15권22호
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• pp.9621-9625
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• 2014

XRCC (X-ray cross-complementing group) genes contribute to important DNA repair mechanisms that play roles in the repair of single strand breaks (SSBs) induced by a variety of external and internal factors, including ionizing radiation, alkylating agents and reactive oxygen species. These repair genes have a pivotal role in maintaining genomic stability through different pathways of base excision repair (BER). The aim of this study was to investigate the XRCC3 Thr241Met gene polymorphism in colorectal cancer (CRC) in Kashmir. We investigated the genotype distribution of XRCC3 gene in 120 CRC cases in comparison with 150 healthy subjects and found a significant association between XRCC3 genotypes and CRC ($p{\leq}0.05$). Both heterozygous genotype (Thr/Met) as well as homozygous variant genotype (Met/Met) were moderately associated with elevated risk of CRC [OR=2.53; OR=2.29 respectively]. Also, Thr/Met and Met/Met genotypes demonstrated a significant association with the risk of CRC (p = 0.003). This study displayed a significantly elevated risk for CRC in individuals with XRCC3 Thr/Met and Met/Met Genotype of about 2.5 times that with the Thr/Thr wild genotype.

• Asian Pacific Journal of Cancer Prevention
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• 제13권7호
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• pp.3431-3436
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• 2012

Objective: X-ray cross-complementing group 4 (XRCC4) is a major repair gene for DNA double-strand breaks (DSB) in the non-homologous end-joining (NHEJ) pathway. Several potentially functional polymorphisms of the XRCC4 gene have been implicated in breast cancer risk, but individually published studies showed inconclusive results. The aim of this meta-analysis was to investigate the association between XRCC4 polymorphisms and the risk of breast cancer. Methods: The MEDLINE, EMBASE, Web of science and CBM databases were searched for all relevant articles published up to June 20, 2012. Potential associations were assessed with comparisons of the total mutation rate (TMR), complete mutation rate (CMR) and partial mutation rate (PMR) in cases and controls. Statistical analyses were performed using RevMan 5.1.6 and STATA 12.0 software. Results: Five studies were included with a total of 5,165 breast cancer cases and 4,839 healthy controls. Meta-analysis results showed that mutations of rs2075686 (C>T) and rs6869366 (G>T) in the XRCC4 gene were associated with increased risk of breast cancer, while rs2075685 (G>T) and rs10057194 (A>G) might decrease the risk of breast cancer. However, rs1805377 (A>G), rs1056503 (G>T), rs28360317 (ins>del) and rs3734091 (A>G) polymorphisms of XRCC4 gene did not appear to have an influence on breast cancer susceptibility. Conclusion: Results from the current meta-analysis suggest that the rs2075685 (G>T) and rs6869366 (G>T) polymorphisms of the XRCC4 gene might increase the risk of breast cancer, whereas rs2075685 (G>T) and rs10057194 (A>G) might be protective factors.

• Asian Pacific Journal of Cancer Prevention
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• 제13권7호
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• pp.3417-3422
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• 2012

Objective: Non-homologous end joining (NHEJ) is one of the pathways of repair of DNA double-strand breaks. A number of genes involved in NHEJ have been implicated as breast cancer susceptibility genes such as LIG4. However, some studies have generated conflicting results. The aim of this Human Genome Epidemiology (HuGE) review and meta-analysis was to investigate association between LIG4 gene polymorphisms in the NHEJ pathway and breast cancer risk. Methods: Studies focusing on the relationship between LIG4 gene polymorphisms and susceptibility to breast cancer were selected from the Pubmed, Cochrane library, Embase, Web of Science, Springerlink, CNKI and CBM databases. Data were extracted by two independent reviewers and the meta-analysis was performed with Review Manager Version 5.1.6 and STATA Version 12.0 software, calculating odds ratios (ORs) with 95% confidence intervals (95%CIs). Results: According to the inclusion criteria, we final included seven studies with a total of 10,321 breast cancer cases and 10,160 healthy controls in the meta-analysis. The results showed no association between LIG4 gene polymorphisms (rs1805386 T>C, rs1805389 C>T, rs1805388 C>T and rs2232641 A>G) and breast cancer risk, suggesting that the mutant situation of these SNPs neither increased nor decreased the risk for breast cancer. In the subgroup analysis by Hardy-Weinberg equilibrium (HWE) and ethnicity, we also found no associations between the variants of LIG4 gene and breast cancer risk among HWE, non-HWE, Caucasians, Asians and Africans. Conclusion: This meta-analysis suggests that there is a lack of any association between LIG4 gene polymorphisms and the risk of breast cancer.

• Archives of Pharmacal Research
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• 제23권5호
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• pp.518-524
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• 2000

We examined the modulation of protein kinase C (PKC) subtypes during apoptosis induced by ginsenoside Rh2 (G-Rh2) in human neuroblastoma SK-N-Bl(2) and rat glioma C6Bu-1 cells. Apoptosis induced by C-Rh2 in both cell lines was confirmed, as indicated by DNA fragmentation and in situ strand breaks, and characteristic morphological changes. During apoptosis induced by G-Rh2 in SK-N-BE(2) cells, PKC subtypes $\alpha$, $\beta$ and $\gamma$ were progressively increased with prolonged treatment, whereas PKC $\delta$ increased transiently at 3 and 6 h and PKC $\varepsilon$ was gradually down-regulated after 6 h following the treatment. On the other hand, PKC subtype $\beta$ markedly increased at 24 h when maximal apoptosis was achieved. In C6Bu-l cells, no significant changes in PKC subtypes $\alpha$, $\gamma$, $\delta$, $\varepsilon$ and $\beta$ were observed during apoptosis induced by G-Rh2. These results suggest the evidence for a possible role of PKC subtype in apoptosis induced by G-Rh2 in SK-N-BE(2) cells but not in C6Bu-1 cells, and raise the possibility that G-Rh2 may induce apoptosis via different pathways interacting with or without PKC in different cell types.

• 생명과학회지
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• 제23권10호
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• pp.1183-1191
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• 2013

APEX-1 (인간 apyrimidinic/apurinic 효소)은 염기성 사이트 및 DNA단일 가닥 결손으로 손상된 DNA을 복구 할 수 있는 다기능 단백질이다. 또한 APEX-1은 많은 전사 인자들의 redox-modifying factor (산화 환원 수정 요소)로서의 역할을 한다고 알려져 있다. 이런 APEX-1의 전사 타겟을 동정하는 것은 APEX-1의 다양한 세포 내 작용 메커니즘을 이해하는데 필수적이다. 따라서 이 논문에서는 먼저 Expression array analysis를 통해 glial cell-derived neurotropic factor receptor ${\alpha}1$ ($GFR{\alpha}1$)을 동정하였다. $GFR{\alpha}1$은 glial cell-derived neurotropic factor (GDNF) family 수용체이며 APEX-1에 의해 발현이 증가된다. APEX-1이 과발현된 세포에서 GDNF처리에 의해 GDNF/$GFR{\alpha}1$ 시그널 타겟인 c-Src가 Tyr418잔기에서 인산화 됨을 관찰하였다. 또한 APEX-1이 과발현된 세포에 GDNF처리하면, 세포증식이 증가함을 보았다. 반면, APEX-1 발현을 siRNA을 이용하여 감소시키면 $GFR{\alpha}1$ 발현과 GDNF에 의한 c-Src 인산화 및 세포증식이 감소함을 확인하였다. 이상의 결과는 APEX-1은 GDNF/$GFR{\alpha}1$ 시그널을 통해 세포 생존과 증식을 조절함을 증명하였다. 따라서 본 연구를 통해 APEX-1의 세포 증식을 조절하는 새로운 기전을 규명하였다.