• Journal of Microbiology and Biotechnology
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• 제27권1호
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• pp.72-76
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• 2017

Detection of exon 19 deletion mutation in the epidermal growth factor receptor (EGFR) gene, which results in increased and sustained phosphorylation of EGFR, is important for diagnosis and treatment guidelines in non-small-cell lung cancer. Here, we have developed a simple and convenient detection system using the interaction between G-quadruplex and fluorophore thioflavin T (ThT) for discriminating EGFR exon 19 deletion mutant DNA from wild type without a label and quencher. In the presence of exon 19 deletion mutant DNA, the probe DNAs annealed to the target sequences were transformed into G-quadruplex structure. Subsequent intercalation of ThT into the G-quadruplex resulted in a light-up fluorescence signal, which reflects the amount of mutant DNA. Due to stark differences in fluorescence intensity between mutant and wild-type DNA, we suggest that the induced G-quadruplex structure in the probe DNA can report the presence of cancer-causing deletion mutant DNAs with high sensitivity.

• Asian Pacific Journal of Cancer Prevention
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• 제17권3호
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• pp.965-971
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• 2016

Aims: To investigate the distribution of epidermal growth factor receptor (EGFR) mutations, and explore any relationships with clinical characteristics in non-small-cell lung carcinoma (NSCLC) patients. Materials and Methods: EGFR mutations were assessed by ADx-ARMS in 261 NSCLC patients from West China Hospital of Sichuan University. Relationships between EGFR mutation and clinical characteristics were analyzed by SPSS. Results: The EGFR mutation rate was 48.7% (127/261), 19-del and L858R mutations occurred predominantly, accounting for 33.1% and 40.9%, respectively, in mutated cases. Moreover, 10.2% patients were found to carry double mutations. EGFR mutations occurred more frequently in women (57.5%) than in men (41.8%) (P=0.01), and were more frequent in non-smokers (61.2%) than in former or current smokers (31.2%) (P<0.00). In addition, they were more common in adenocarcinomas (52.8%) and adenosquamous carcinomas (42.8%) than in squamous cell carcinomas (14.8%) (p<0.00). However, only smoking history and pathological types, rather than gender, proved to be associated with EGFR mutations on multivariate logistic regression analysis. No significant differences in pathological stage and metastasis status were found between EGFR wild-type and mutated cases, although EGFR mutation type was related to pathological type (p=0.00) - 19-del, L858R and other mutation types respectively occurred in 34.2%, 42.5% and 23.3% of adenocarcinomas, but in 14.3%, 0% and 85.7% of non-adenocarcinomas. Conclusions: The EGFR mutation rate was 48.7% in NSCLCs in Southwest China, so that nearly 40% patients might benefit from targeted therapies. Smoking status and pathological types were independent predictors of EGFR mutation, while EGFR mutation type was related to only pathological type, rather than smoking status.

• Interdisciplinary Bio Central
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• 제4권2호
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• pp.3.1-3.7
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• 2012

Epidermal growth factor receptor (EGFR) is a member of the ErbB family (ErbB1-4) of receptor tyrosine kinases (RTKs). EGFR controls numerous physiological functions, including cell proliferation, migration, differentiation and survival. Importantly, aberrant signaling by EGFR has been linked to human cancers in which EGFR and its various ligands are frequently overexpressed or mutated. EGFR coordinates activation of multiple downstream factors and is subject of various regulatory processes as it mediates biology of the cell it resides in. Therefore, many studies have been devoted to understanding EGFR biology and targeting the protein for the goal of controlling tumor in clinical settings. Endocytic regulation of EGFR offers a promising area for targeting EGFR activity. Upon ligand binding, the activated receptor undergoes endocytosis and becomes degraded in lysosome, thereby terminating the signal. En route to lysosome, the receptor becomes engaged in activating various signaling pathways including PI-3K, MAPK and Src, and endocytosis may offer both spatial and temporal regulation of downstream target activation. Therefore, endocytosis is an important regulator of EGFR signaling, and increasing emphasis is being placed on endocytosis in terms of cancer treatment and understanding of the disease. In this review, EGFR signaling pathway and its intricate regulation by endocytosis will be discussed.

• Asian Pacific Journal of Cancer Prevention
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• 제14권6호
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• pp.3705-3709
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• 2013

Background: To investigate epidermal growth factor receptor (EGFR) gene mutations in patients with non-small cell lung cancer (NSCLC) and to analyze any relationship with clinicopathological features and prognosis. Materials and Methods: EGFR gene exons 18-21 in 48 specimens of paraffin-embedded tumor tissue from NSCLC patients were amplified by PCR, followed by direct sequencing and analysis of links to clinicopathological features and prognosis. Results: EGFR mutations were detected in 18 of 48 (42.6%) patients with NSCLC. There were 9 cases of mutations in exon 20, 7 in exon 19 and 2 in exon 21. Mutations were more frequently observed in women (5/7 pts, 71.4%) than in men (13/41 pts, 31.7%) (p=0.086) and in non-smokers (5/5 pts, 100%) than smokers (13/43 pts, 30.2%). There was negative correlation of EGFR mutations with smoking status (p=0.005). EGFR mutations were more frequently observed with adenocarcinoma histology (13/32 pts, 40.6%) than in other types (5/16 pts, 31.3%) (p=0.527). The patients with EGFR mutations had better survival than those with wild-type EGFR (p=0.08). There was no association of EGFR mutations with metastatic spread. Conclusions: EGFR mutations in NSCLC were here demonstrated more frequently in females, non-smokers and adenocarcinoma histology in the western region of Turkey. Patients with EGFR mutations have a better prognosis.

• Radiation Oncology Journal
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• 제28권3호
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• pp.147-154
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• 2010

목 적: 대장암 세포에서 epidermal growth factor receptor (EGFR) 저해제인 nimotuzumab에 의한 방사선 민감도 증진 효과를 살펴보고자 한다. 대상 및 방법: 총 4종류의 인간 유래 대장암 세포주인 HCT-8, LoVo, WiDr, HCT-116를 nimotuzumab과 방사선을 병합 처리한 후 세포증식, 생존율, 세포주기 진행에 미치는 영향을 MTT, clonogenic survival assay, flow cytometry와 western blot을 통해 분석하였다. 결 과: 대장암 세포주에서 nimotuzumab에 의해 EGFR 인산화가 억제됨을 확인하였고 이러한 조건에서 nimotuzumab이 HCT-116을 제외한 나머지 3종류의 대장암 세포주의 방사선 민감도를 증진시킴을 확인하였다. 반면에, nimotuzumab은 방사선 조사와 무관하게 대장암 세포의 증식이나 세포 주기에는 아무런 영향을 미치지 않았다. 결 론: Nimotuzumab은 EGFR에 의한 세포 생존 신호 전달을 억제함으로써 대장암 세포의 방사선에 대한 민감도를 증가시켰다. 본 연구는 대장암의 방사선 치료에 EGFR 특이적 저해제인 nimotuzumab의 임상 적용 근거를 제공하였다.

• Journal of Microbiology and Biotechnology
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• 제30권5호
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• pp.662-667
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• 2020

Epidermal growth factor receptor (EGFR) mutations are not only genetic markers for diagnosis but also biomarkers of clinical-response against tyrosine kinase inhibitors (TKIs) in non-small cell lung cancer (NSCLC). Among the EGFR mutations, the in-frame deletion mutation in EGFR exon 19 kinase domain (EGFR exon 19-del) is the most frequent mutation, accounting for about 45% of EGFR mutations in NSCLCs. Development of sensitive method for detecting the EGFR mutation is highly required to make a better screening for drug-response in the treatment of NSCLC patients. Here, we developed a fluorometric tandem gene amplification assay for sensitive detection of low-abundance EGFR exon 19-del mutant genomic DNA. The method consists of pre-amplification with PCR, thermal cycling of ligation by Taq ligase, and subsequent rolling circle amplification (RCA). PCR-amplified DNA from genomic DNA samples was used as splint DNA to conjugate both ends of linear padlock DNA, generating circular padlock DNA template for RCA. Long stretches of ssDNA harboring multiple copies of G-quadruplex structure was generated in RCA and detected by thioflavin T (ThT) fluorescence, which is specifically intercalated into the G-quadruplex, emitting strong fluorescence. Sensitivity of tandem gene amplification assay for detection of the EGFR exon 19-del from gDNA was as low as 3.6 pg, and mutant gDNA present in the pooled normal plasma was readily detected as low as 1% fraction. Hence, fluorometric detection of low-abundance EGFR exon 19 deletion mutation using tandem gene amplification may be applicable to clinical diagnosis of NSCLC patients with appropriate TKI treatment.

• Tuberculosis and Respiratory Diseases
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• 제52권1호
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• pp.37-45
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• 2002

연구배경 : 미만성 범세기관지염은 임상적으로 기침, 객담 및 노작성 호흡곤란을 특징으로 하며 기관지확장증으로 진행하는 만성 염증성 폐질환이다. 기관지확장증의 발생 기전은 정액 과다분비 및 배상세포의 이형성과 동반된 염증성 매개물질에 의해 조절되며 이 과정에서 epidermal growth factor receptor (EGFR)가 관여하는 것으로 알려져 있다. 미만성 범세기관지염 환자에서의 배상세포의 이형성과 EGFR의 발현, 호중구에 의한 염증성 매개물질 사이의 연관을 살펴보았다. 방 법 : 13명의 미만성 범세기관지염 환자군과 6명의 정상 대조군을 대상으로 점액 과다분비에 대한 EGFR의 역할을 보기 위해 alcian blue/periodic acid(AB/PAS) 염색과 MUC5AC, EGFR, CD16 면역 조직 화학 염색을 시행하였다. 결 과 : 미만성 범세기관지염 환자군의 AB/PAS 염색과 MUC5AC 염색 정도는 $8.31{\pm}3.36%$, $11.46{\pm}4.68%$ 이었고, 정상 대조군의 AB/PAS 염색과 MUC5AC 염색은 $50.5{\pm}5/77%$, $53.3%{\pm}6.67%$로 정상 대조군에서 환자군에 비해 유의하게 높았다(p<0.05). EGFR의 발현은 환자군에서는 $9.54{\pm}4.95%$이었으나 정상 대조군에서는 전혀 나타나지 않았다. 호중구 침윤은 환자군에서 $71.92{\pm}3.71$HPF 이었고, 정상 대조군에서는 $45.0{\pm}5.73$/HPF로 환자군에서 정상 대조군에 비해 유의하게 높았다(p=0.002). 결 론 : 미만성 범세기관지염에서 EGFR의 발현이 점액 과다 분비와 배상세포의 이형성 및 호중구성 염증과 연관을 보이는 것으로 사료된다.

• Tuberculosis and Respiratory Diseases
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• 제75권6호
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• pp.236-237
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• 2013

Many attempts have been made to find genetic abnormalities inducing carcinogenesis after the development of epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor targeting EGFR in lung cancer. New target therapies have been already commercialized and studied along with the recent discovery of gene rearrangement involved in the carcinogenic process of non-small cell lung cancer. This study aims to investigate anplastic lymphoma kinase, c-ros oncogene 1, and receptor tyrosine kinase, in particular.

• BMB Reports
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• 제51권1호
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• pp.27-32
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• 2018

Non-small-cell lung cancer (NSCLC) is commonly caused by a mutation in the epidermal growth factor receptor (EGFR) and subsequent aberrant EGFR signaling with uncontrolled kinase activity. A deletion mutation in EGFR exon 19 is frequently observed in EGFR gene mutations. We designed a DNAzyme to suppress the expression of mutant EGFR by cleaving the mutant EGFR mRNA. The DNAzyme (named Ex19del Dz) specifically cleaved target RNA and decreased cancer cell viability when transfected into gefitinib-resistant lung cancer cells harboring EGFR exon 19 deletions. The DNAzyme decreased EGFR expression and inhibited its downstream signaling pathway. In addition to EGFR downregulation, Ex19del Dz containing CpG sites activated Toll-like receptor 9 (TLR9) and its downstream signaling pathway via p38 kinase, causing an immunostimulatory effect on EGFR-mutated NSCLC cells. Thus, dual effects of this DNAzyme harboring the CpG site, such as TLR9 activation and EGFR downregulation, leads to apoptosis of EGFR-mutated NSCLC cells.

• Molecules and Cells
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• 제43권3호
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• pp.264-275
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• 2020

Reactive oxygen species (ROS) play a significant role in intracellular signaling and regulation, particularly when they are maintained at physiologic levels. However, excess ROS can cause cell damage and induce cell death. We recently reported that eIF2α phosphorylation protects hepatocytes from oxidative stress and liver fibrosis induced by fructose metabolism. Here, we found that hepatocyte-specific eIF2α phosphorylation-deficient mice have significantly reduced expression of the epidermal growth factor receptor (EGFR) and altered EGFR-mediated signaling pathways. EGFR-mediated signaling pathways are important for cell proliferation, differentiation, and survival in many tissues and cell types. Therefore, we studied whether the reduced amount of EGFR is responsible for the eIF2α phosphorylation-deficient hepatocytes' vulnerability to oxidative stress. ROS such as hydrogen peroxide and superoxides induce both EGFR tyrosine phosphorylation and eIF2α phosphorylation. eIF2α phosphorylation-deficient primary hepatocytes, or EGFR knockdown cells, have decreased ROS scavenging ability compared to normal cells. Therefore, these cells are particularly susceptible to oxidative stress. However, overexpression of EGFR in these eIF2α phosphorylation-deficient primary hepatocytes increased ROS scavenging ability and alleviated ROS-mediated cell death. Therefore, we hypothesize that the reduced EGFR level in eIF2α phosphorylation-deficient hepatocytes is one of critical factors responsible for their susceptibility to oxidative stress.