Association between the DNA Repair Gene Polymorphisms and Lung Cancer in Turkish Population

Introduction: DNA repair enzymes continuously monitor DNA to correct damaged nucleotide residues generated by exposure to environmental mutagenic and cytotoxic compounds or carcinogens. Our objective was to investigate the association among XRCC1 (Arg399Gln and Arg194Trp), XRCC3 (Thr241Met), XPD-ERCC2 (Lys751Gln), APE1 (Asp241Glu), PARP-ADPRT (Val762Ala) DNA repair gene polymorphisms and lung cancer in Turkish population. Materials and Methods: Our patient group consists of 90 patients with lung cancer and the control group had 100 healthy individuals all of those smoking. DNA was extracted using the whole blood samples. PCR- RFLP technique was used to investigate the polymorphisms on target genes. Results: There was no significant difference in the genotype distributions of XPD Lys751Gln, XRCC1 Arg194Trp, XRCC3 Thr241Met, APE1 Asp241Glu between lung cancer patients and controls for each polymorphism (p > 0.05). However, there was a significant difference between the genotype distributions of XRCC1 Arg399Gln, and PARP Val762Ala in patients and the control group (p > 0.05). Discussion: Only the polymorphisms of XRCC1 codon 399 and PARP Val762Ala alleles are associated with the risk of lung cancer. Other genotypes were not related to lung cancer.

In Vivo Improvements in Facial Appearance and in Vitro Changes in Gene Expression Using a Topical Formulation Designed to Repair Environmentally Induced DNA Damage

Background: While sunscreen has been accepted as a mainline defence against photodamage from ultraviolet, visible light and near-infrared radiation, there appears to be a lack of research into photorepair. The concept of protecting the skin during the day and repairing cellular damage at night is intuitive, yet specific strategies revolving around combinations of proven reparative active ingredients remain unelucidated. Purpose: To investigate the efficacy of a solar repair Formulation following ultraviolet and environmental exposure in order to improve overall skin health and appearance through three hypotheses: The Formulation increases expression of DNA repair mechanisms markers;The Formulation enhances overall skin appearance through reducing signs of inflammation, elevating hydration, reinforcing skin firmness and amplifying radiance;In-Vivo efficacy test results are aligned with measured gene expression changes. Methods: The Formulation (#6NIC1.V1.1-1) was tested for: In-vitro LDH cytotoxicity activity, In-vitro qPCR gene expression with and without ultraviolet exposure on a reconstructed 3-dimensional skin model, and In-Vivo efficacy study on a panel of 22 participants objectively and subjectively. Results: Skin radiance, firmness, hydration, redness, and inflammation are significantly improved after In-Vivo skin exposure to the Formulation and environmental challenges such as ultraviolet radiation. These outcomes were confirmed by in-vitro genetic testing on a reconstructed human skin model. Conclusion: The studies allowed us to identify and group results in four main skin functions that were significantly enhanced following the application of the Formulation: firmness, hydration, radiance and soothing.

Expressions of genes related to genome stability and DNA repair in nasopharyngeal carcinoma clustering families

Objective： The aim of the study was to observe the expressions of genes related to genome stability and DNA repair in the members of nasopharyngeal carcinoma （NPC） clustedng families. Methods： In the Zhongshan City where there is highly incidence rate of NPC, we chose the members of the NPC clustering families as objects, and the patients of nasopharyngitis and NPC as the control group. We isolated the RNA from the nasopharyngeal tissue, and synthesized its cRNA, the genome stability and DNA repair genes chip technique, chemiluminescent detection and real-time fluorescence quantita- tive technique were used to examine the genome stability and DNA repair genes in the nasopharyngeal tissue. Results： More genome stability and DNA repair genes were up-regulated in the members of the NPC clustering families than the NPC patients, and the range of up-regulated was high, with the over up-regulated 100 times genes including TEP1, MSH4, PMS2LI. Fewer genome stability and DNA repair genes were down-regulated in the members of the NPC clustering families than the NPC patients, the ubiquitin genes almost were down-regulated, the results also could be confirmed by real-time fluorescence quantitative PCR. Conclusion： There are specially expression character of genome stability and DNA repair genes in the members of NPC clustering families.

Microsatellite instability and expression of DNA mismatch repair genes in malignant astrocytic tumors from adult and pediatric patients

Microsatellite instability (MSI) is used as a molecular marker for defective DNA mismatch repair (MMR) genes.We report here alterations of MSI in 15 malignant astrocytomas (WHO grade Ⅲ) and glioblastomas (GBM; WHO grade Ⅳ) of pediatric patients (2-21 years) and 12 GBM from adults (44-68 years) by comparative analysis of BAT25/BAT26 loci and 10 other microsatellite markers. High-level microsatellite instability (MSI-H) occurred in 4 of the 15 pediatric cases (26.7%) and in 1 of the 12 adult GBM cases (8.3%). Low-level mi-

CORRECTION OF DNA REPAIR GENE DEFICIENCY IN MAMMALIAN CELLS BY HUMAN HeLa S3. DNA TRANSFECTION

Study on the DNA damage and repair, especially in the mammalian cells, is one of the frontier topics in life sciences. By means of human DNA-mediated gene transfer (DMGT) method, the genes responsible for DNA repair are introduced into two kinds of repair gene defective mammalian cells. The purpose is to correct their gene deficiency and to study the mechanism of DNA damage and repair induced by radiation or alkylating agents.

Development of a prognostic signature for esophageal cancer based on a novel 7-DNA damage repair genes signature

Esophageal cancer(EC)was an aggressive malignant neoplasm characterized by high morbidity and poor prognosis.Identifying the changes in DNA damage repair genes helps to better understand the mechanisms of carcinoma progression.In this study,by comparing EC samples and normal samples,we found a total of 132 DDR expression with a significant difference.Moreover,we revealed higher expression of POLN,PALB2,ATM,PER1,TOP3B and lower expression of HMGB1,UBE2B were correlated to longer OS in EC.In addition,a prognostic risk score based on 7 DDR gene expression(POLN,HMGB1,TOP3B,PER1,UBE2B,ATM,PALB2)was constructed for the prognosis of EC.Meanwhile,EC cancer samples were divided into 3 subtypes based on 132 DDR genes expressions.Clinical profile analysis showed cluster C1 and C2 showed a similar frequency of T2,which was remarked higher than that in cluster 3.Moreover,we found the immune cell inflation levels were significantly changed in different subtypes of EC.The infiltration levels of T cell CD8+,B cell and NK cells were greatly higher in cluster 2 than that in cluster 1 and cluster 3.The results showed T cell CD4+infiltration levels were dramatically higher in cluster 1 than that in cluster 2 and cluster 3.Finally,we perform bioinformatics analysis of DEGs among 3 subtypes of EC and found DDR genes may be related to multiple signaling,such as Base excision repair,Cell cycle,Hedgehog signaling pathway,and Glycolysis/Gluconeogenesis.These results showed DDR genes may serve as new target for the prognosis of EC and prediction of the potential response of immune therapy in EC.

DNA损伤修复基因表达与甲基化对肝细胞癌预后的影响及风险评分模型构建

目的探讨DNA损伤修复基因表达与甲基化对肝细胞癌(HCC)预后的影响及风险评分模型构建。方法研究时间为2024年1月至5月,由TCGA、GTEx、GEO数据库获得数据集,采用Kaplan-Meier生存分析探讨DNA损伤修复基因对HCC患者生存预后的影响,利用单因素与多因素COX比例风险回归分析关键DNA损伤修复基因、年龄、性别、肿瘤分期等因素对患者预后的影响,构建并验证Nomogram预测模型,采用一致性系数(C-index)评估Nomogram预测模型的预测效果;采用Lasso回归法建立HCC生存预后的风险预后评分模型。利用HPA数据库验证结果与上述分析结果一致。结果8个差异表达DNA损伤修复基因(FEN1、RNASEH2A、MCM6、EXO1、RECQL4、MCM4、MCM3、MCM5)对HCC患者生存预后具有影响(均P<0.05);COX回归分析结果显示,MCM6、pTNM分期对HCC总生存率(OS)具有独立影响;列线图模型显示MCM6、pTNM分期与患者生存预后相关(均P<0.05,C-index=0.677);预后风险评分模型显示,RECQL4、EXO1和MCM6是影响HCC患者生存预后的关键基因。RECQL4、EXO1和MCM6基因启动子区甲基化水平随着HCC分级的升高而降低(均P<0.05)。结论DNA损伤修复基因在HCC的进展过程中发挥一定作用,RECQL4、EXO1和MCM6进入HCC患者生存预后的风险预后评分模型,MCM6对HCC患者生存预后具有独立的影响。

Hypersensitive Inhibition of the Proliferation of Cells with Mutated DNA Repair-Related Genes by the Catalytic Topoisomerase II Inhibitor 20-O-IngenolEZ

We previously reported that many ingenol compounds derived from Euphoria kansui exhibit topoisomerase inhibitory activity. 20-O-ingenolEZ in these compounds exerted inhibitory effects on both topoisomerase II (topo II) activity and cell proliferative activity. Topoisomerase II inhibitors can be divided into the poison and catalytic inhibitor types and 20-O-ingenolEZ is a catalytic inhibitor and inhibits topo IIα through inhibition of ATPase activity, but induces topo II-mediated DNA damage and apoptosis in BLM-/- DT40 cells through the induction of the DNA damage checkpoint, similar to the poison type inhibitor adriamycin. The ATPase inhibitor of topo II ICRF-193 also showed poison-like characteristics in the same cell line. However, the inhibitory effects of ICRF-193 on the proliferation of BLM-/- DT40 cells differed from those of 20-O-ingenolEZ, as did the specificity of its inhibition of the proliferation of other cell lines. 20-O-ingenolEZ showed hypersensitive inhibition of the proliferation of MCF-7 cells and BLM-/- DT40 cells with mutated DNA repair-related genes.

DNA损伤修复基因胚系突变乳腺癌新辅助化疗疗效分析

目的:分析携带DNA损伤修复(DNA damage repair,DDR)相关基因突变的乳腺癌患者对基础蒽环类新辅助化疗方案(anthracycline,A)、蒽环联合紫杉类新辅助化疗方案(anthracycline-taxane,A-T)、蒽环联合紫杉和铂类新辅助化疗方案(anthracycline-taxane/carboplatin,A-TP)的疗效反应。方法:2003年10月至2015年5月,105例携带DDR基因胚系突变(非BRCA)的原发性乳腺癌患者在北京大学肿瘤医院分别接受A(n=69)、A-T(n=19)、A-TP(n=17)3种新辅助化疗方案。通过χ2检验或Fisher精确检验比较3组患者的病理完全缓解(pathological complete remission,pCR)率;采用Kaplan-Meier生存分析和Cox回归模型分析患者的乳腺癌特异生存(breast cancer-specific survival,BCSS)及无复发生存(recurrence-free survival,RFS)。结果:93.3%(98/105)的患者接受了4~8个周期的新辅助化疗。接受A、A-T、A-TP新辅助方案的3组患者的pCR率分别为11.6%、21.1%和35.3%。A-TP组pCR率显著高于A组(P=0.028),A-TP组pCR率也高于A-T组,但未达到统计学差异。经过65.6个月的中位随访,A-TP组的BCSS(HR=0.50,95%CI:0.09~2.73,P=0.41)和RFS(HR=0.51,95%CI:0.15~1.74,P=0.27)略优于A-T组,但无统计学差异。结论:DDR基因胚系突变患者应用A-TP新辅助化疗方案可显著提高pCR率,加入铂类药物或可提高患者的药物反应性及预后。

胶质母细胞瘤FGFR3-TACC3融合基因介导丙酮酸激酶M2入核促进DNA损伤修复基础研究

目的探讨胶质母细胞瘤FGFR3-TACC3(F3-T3)融合基因介导丙酮酸激酶M2(PKM2)入核激活DNA损伤修复致替莫唑胺(TMZ)耐药的作用机制。方法慢病毒转染构建稳定表达F3-T3融合基因和空载体的胶质母细胞瘤细胞系U87MG和U251MG,构建稳定表达F3-T3融合基因的胶质母细胞瘤裸鼠模型,小动物活体成像系统观察荷瘤鼠肿瘤荧光信号强度;采用生物信息学分析基因芯片转录组数据分析F3-T3融合基因的生物学功能,并分析肿瘤基因组学图谱计划(TCGA)数据库中胶质瘤患者生存期与PKM2基因表达的关系;瞬时转染小干扰RNA(siRNA)敲低PKM2基因表达;CCK-8细胞增殖实验观察经梯度浓度替莫唑胺处理后、转染siRNA后、替莫唑胺联合PKM2抑制剂Compound 3k处理后U87MG和U251MG细胞增殖活性;提取核质蛋白并观察经替莫唑胺处理后总蛋白提取物、胞质提取物和胞核提取物PKM2蛋白表达情况;Western blotting法检测稳定表达F3-T3融合基因的U87MG和U251MG细胞PKM2蛋白相对表达量、磷酸化组蛋白H2AX(p-H2AX)相对表达量、siRNA敲低PKM2基因p-H2AX相对表达量。结果(1)CCK-8细胞增殖实验显示,经替莫唑胺640、320、160、80、40μmol/L处理后F3-T3转染组的U87MG细胞存活率均高于空载体转染组(P=0.000,0.000,0.000,0.004,0.010),经替莫唑胺640、320、160、80、40、20、5μmol/L处理后F3-T3转染组的U251MG细胞存活率亦均高于空载体转染组(P=0.000,0.000,0.000,0.000,0.002,0.001,0.002);然而,经替莫唑胺640、320、160、80、40、20、10、5和2.50μmol/L处理后si-PKM2-1009转染组的U87MG细胞存活率均低于F3-T3转染组(P=0.000,0.000,0.000,0.012,0.006,0.030,0.000,0.007,0.025),经替莫唑胺640、320、160、80、40、20、5μmol/L处理后si-PKM2-1377转染组U251MG细胞存活率亦低于F3-T3转染组(P=0.000,0.000,0.002,0.000,0.002,0.048,0.042);经替莫唑胺640、320、160、80、40、20μmol/L处理后TMZ+Compound 3k组U87MG细胞存活率低于TMZ组(P=0.000,0.000,0.000,0.000,0.001,0.002),经高浓度(640、320、160、80、40μmol/L)替莫唑胺处理后TMZ+Compound 3k组U251MG细胞存活率亦低于TMZ组(P=0.000,0.000,0.000,0.000,0.003),而经低浓度(10、5、2.50μmol/L)替莫唑胺处理后TMZ+Compound 3k组U251MG细胞存活率高于TMZ组(P=0.000,0.000,0.006)。(2)胶质母细胞瘤动物模型显示,荷瘤鼠存在替莫唑胺耐药。(3)生物信息学分析,F3-T3融合蛋白的生物学功能显著富集于DNA修复通路(P=0.000)。TCGA数据库中胶质瘤患者PKM2基因高表达组生存率和总生存期均低于低表达组(P<0.05)。(4)Western blotting法显示,经替莫唑胺处理48 h再更换培养基后24、36和48 h,F3-T3转染组U87MG(P=0.000,0.000,0.004)和U251MG(P=0.000,0.007,0.005)细胞p-H2AX蛋白相对表达量均低于空载体转染组;经替莫唑胺处理后F3-T3转染组U87MG和U251MG细胞均可见明显的PKM2入核,而空载体转染组细胞均未见这一现象;si-PKM2-1009和si-PKM2-1377分别敲低U87MG(P=0.000,0.001,0.006)和U251MG(P=0.000,0.000,0.000)细胞PKM2基因表达的效果最显著。结论F3-T3融合基因可促进PKM2入核,激活DNA损伤修复相关通路,进而介导胶质母细胞瘤对替莫唑胺耐药,不同细胞株对替莫唑胺的耐药浓度不一致,PKM2抑制剂可逆转这种耐药。

Up-Regulated Expression of SOD2 and HPRT1 Following Topical Photoprotection and Photorepair Skincare Formulations in A 3-Dimensional Reconstructed Human Skin Model

Photodamage continues to threaten human skin health despite worldwide sun awareness campaigns and the widespread use of sunscreens. To date, extensive research is lacking into the effects of sun avoidance and solar specific skincare regimens on gene expression changes and DNA repair activity. We have previously reported that photoprotection and photorepair formulations which minimize the harmful effects of ultraviolet, visible light and near-infrared radiation can provide photoprotection, anti-photoaging benefits and rejuvenating effects optically, clinically and genetically. To investigate gene expression changes, specifically antioxidant and DNA repair effects following the use of topical photoprotection and photorepair formulations (The Essential Six, RATIONALE, Victoria, Australia), we used epidermal keratinocytes and dermal fibroblasts derived from a 3-dimensional reconstructed human skin model, and assessed upregulation of SOD2 and HPRT1. Gene expression was assessed via the Genemarkers Standard Skin Panel and quantitative real-time PCR exploration. Tissues were inoculated with solar specific topical formulations, then collected after 24 hours following application of photoprotection formulations and 16 hours following photorepair formulations. The quantitative real-time PCR revealed that, in comparison to the control, the genes encoding SOD2 and HPRT1 have been significantly up-regulated following usage of the photoprotection formulations, 1.86, and 1.41, respectively. SOD2 and HPRT1 were up-regulated following use of the photorepair formulations, 2.15, and 1.28, respectively. We were able to substantiate that the photo protection and photorepair formulations upregulated genes involved in antioxidant and DNA repair mechanisms in a 3-dimensional reconstructed human skin model, suggesting a promising anti-photoaging skin regimen. .

砷中毒患者皮肤组织中DNA修复基因的表达变化

目的检测DNA修复基因MGMT、XRCC1、hMSH2mRNA在燃煤型砷中毒患者皮肤组织中的表达变化,探讨其表达与砷性皮肤癌发生发展及临床病理特征之间的关系。方法应用原位杂交技术检测了61例砷中毒患者皮肤组织中MGMT、XRCC1、hMSH2mRNA的表达变化。结果随着砷中毒患者皮肤病变的发展,MGMT、XRCC1、hMSH2mRNA的表达逐渐降低,癌变组MGMT和XRCC1mRNA阳性表达率与一般病变组比较差异有统计学意义(P<0.05、P<0.01)。结论MGMT、XRCC1、hMSH2作为DNA损伤修复基因,在砷性皮肤病变过程中起重要作用;砷可能通过抑制砷中毒患者皮肤组织中MGMT、XRCC1等DNA修复基因的表达,影响基因组DNA稳定性和DNA修复功能而导致对皮肤的致癌作用。

DNA修复基因XPD多态性和肝细胞肝癌危险性的病例-对照研究

目的 探讨DNA修复基因XPD多态性和肝细胞肝癌 (Hepatocellularcarcinoma ,HCC)发生的关系。方法 应用病例 对照研究方法 ,选择了江苏启东地区 72例HCC患者以及 137例正常对照 ,以年龄 (± 3岁 )和性别为配对因素进行了配对 ,对XPD 75 1位点基因多态性作PCR RFLP分析。结果 XPD 75 1位点的Gln/Lys或Gln/Gln基因型的发生频率在病例组中明显高于对照组 ,差别有显著性 (OR =3.13,95 %CI =1.16～ 8.4 7) ,在调整了HBV感染因素后 ,差别的显著性虽然消失 ,但可信限下限位于临界处 (OR =2 .70 ,95 %CI =0 .98～ 7.4 2 )。对HBV感染患者并同时伴有XPD 75 1位点为Gln/Lys或Gln/Gln基因型的个体 ,其HCC发生的危险性是HBV阴性及XPD 75 1位点为Lys/Lys野生型基因型个体的 6 .6 8倍 ,差别有显著性 (OR=6 .6 8,95 %CI=3.4 3～ 13.0 1)。结论 本次研究的结果首次应用病例 对照研究发现XPD 75 1位点基因多态性可能影响HCC的发生 ,同时指出XPD 75

非小细胞肺癌NP方案化疗敏感性与DNA修复基因XRCC1多态性的关系

背景与目的:基因多态预测肿瘤化疗药物敏感性对肿瘤个体化治疗具有重要意义。本研究旨在探讨DNA修复基因XRCC1 codon194及399位点基因多态性与非小细胞肺癌长春瑞滨加顺铂(vinorelbine and cisplatin,NVB and DDP,NP)方案化疗敏感性的关系。方法:采用聚合酶链反应-限制性片段长度多态性技术检测164例非小细胞肺癌患者外周血DNAXRCC1194和399位点的多态性。选择NP方案化疗,化疗两周期后评价疗效,并分析化疗敏感性与基因多态性的关系。结果:携带XRCC1基因Codon194C/T+T/T基因型者化疗有效率(41.8%)是C/C基因型者(26.0%)的2.038倍(P=0.036,95%CI=1.044-3.976)。携带XRCC1基因Codon399G/G、A/G、A/A型的患者化疗有效率(37.1%,34.6%,14.3%)之间的差异无统计学意义(P>0.05)。

甲醛暴露工人XRCC1基因多态性与DNA损伤的关系研究

目的探讨甲醛暴露工人DNA修复基因XRCC1多态性与外周血淋巴细胞DNA损伤的关系。方法选择某密度板厂的151名甲醛暴露工人(暴露组)和某推土机厂的112名非甲醛暴露工人(对照组)为研究对象。用气相色谱法检测作业环境的甲醛浓度,应用彗星实验测定研究对象外周血淋巴细胞DNA损伤,以Olive尾距和彗星尾长反映DNA损伤水平,用PCR-RFLP方法分析XRCC1基因的多态性;用多元协方差分析调整工人的年龄、工龄、职业甲醛暴露及吸烟与饮烟情况,比较XRCC1基因不同基因型个体的Olive尾距和彗星尾长。结果使用多元协方差分析校正甲醛暴露工人的年龄、工龄、甲醛暴露水平和吸烟与饮酒情况后,携带Arg280His位点变异基因型个体的Olive尾距和彗星尾长(几何均值分别为4.30和13.42)均显著高于野生型基因型的个体(几何均值分别为3.38和11.71),差异均有显著性(Olive尾距:P<0.05,彗星尾长:P<0.01);未发现XRCC1基因其他3个位点的多态性与甲醛暴露工人Olive尾距和彗星尾长有显著关联。结论XRCC1基因Arg280His位点的多态性影响甲醛暴露工人的DNA损伤水平。

中国人DNA修复基因XRCC1 Pro206Pro和Gln632Gln单核苷酸多态与肺癌发生风险

目的:DNA修复系统基因在维持基因组整体性及预防癌变过程中起着重要作用。碱基切除修复是DNA修复途径之一,主要切除DNA分子的小型损伤。XRCC1蛋白分子是碱基切除修复途径的重要组成成分。本研究探讨了DNA修复基因XRCC1 Pro206Pro与Gln632Gln单核苷酸多态与肺癌发生风险。方法:采用PCR-RFLP分型技术,分析中国东北地区汉族群体中247例肺癌患者与253例正常对照者的XRCC1 Pro206Pro和Gln632Gln多态/单体型与肺癌易感性及其与吸烟之间的关联。肺癌病例与正常对照者在年龄(±3岁)、性别及民族方面相配对。结果:XRCC1 Pro206Pro(G)变异等位基因携带者与AA野生等位基因纯合子个体相比较,有1.96倍高的肺癌发生风险(ad-justedOR=1.96,95%CI=1.26～3.06,P=0.003)(OR值经吸烟史校正)。对于XRCC1 Gln632Gln单一位点研究,未发现有统计学意义。分层分析未观察到基因型与吸烟史之间可能的基因与环境的相互作用。两个SNPs之间存在强烈的连锁不平衡(D’=0.807,P=3.1e-115),单体型在肺癌组与对照组之间的总体分布有极显著性差异(P=2.25e-06)。单体型2(Pro206Pro(A)-Gln632Gln(G)是抗风险性单体型(OR=0.66,95%CI=0.45～0.96,P=0.03),而单体型4(Pro206Pro(G)-Gln632Gln(G)是高风险性单体型(OR=16.09,95%CI=3.89～66.53,P=3.09e-07),这表明了基因与基因之间的相互作用对于复杂疾病研究的重要性。结论:XRCC1Pro206Pro等位基因及含其等位基因的单体型可能在肺癌的发生过程中起着重要作用。

甲基丙烯酸环氧丙酯致人支气管上皮恶性转化细胞DNA修复基因点突变的研究

背景与目的:研究甲基丙烯酸环氧丙酯(glycidyl methacrylate,GMA)致人支气管上皮(16HBE)恶性转化细胞DNA修复基因点突变情况。材料与方法:采用聚合酶链式反应-限制性片段长度多态性方法(PCR-RFLP)检测GMA致16HBE恶性转化细胞DNA修复基因hMSH2、XRCC1、XPD及XRCC3的重要位点的突变情况,并以DNA测序方法加以验证。结果:16HBE细胞hMSH2IVS12-6(T>C)位点发生了突变,由野生基因型TT型突变为TC基因型,其它位点未检测到突变。DNA测序结果相符。结论:错配修复基因hMSH2IVS12-6(T>C)位点的突变可能为GMA诱导人支气管上皮细胞恶性转化过程中的重要起始分子事件之一。

COX多因素分析和ROC曲线综合评价DNA修复基因对鼻咽癌的预后价值

目的应用COX多因素分析和ROC曲线探讨DNA修复基因对鼻咽癌的预后价值。方法收集2007年5月至2012年2月经广西壮族自治区人民医院病理科确诊为鼻咽癌且选择调强放射治疗的患者100例。筛选随访时间超过1年的患者共71例,用免疫组化SP法检测鼻咽癌组织中DNA修复基因DNA-PKcs及BRCA1的表达。用Spearman分析DNA-PKcs和BRCA1的表达水平与临床特征的相关性;ROC曲线法建立预后分组,用Kaplan-Meier生存曲线对DNA-PKcs、BRCA1的表达与预后关系进行单因素分析;Cox比例风险回归对预后进行多因素生存分析。结果 1)DNA-PKcs的表达水平和患者的生存时间呈正相关(P<0.05)。2)DNA-PKcs高表达患者的生存时间长于低表达的患者(P<0.01)。3)多因素生存分析,DNA-PKcs表达水平是影响预后的独立因素(P<0.01),而BRCA1表达水平未能得出类似结果。结论 DNA-PKcs表达状态是影响预后的独立因素。DNA-PKcs高表达可能作为预测鼻咽癌患者预后较好的一个指标。

DNA损伤修复基因hOGG1的遗传多态与肝癌易感性研究

目的:探索DNA损伤修复基因hOGG1的遗传多态Ser326Cys与肝细胞肝癌易感性的关系。方法:对96例原发性肝细胞肝癌患者和96例对照外周血DNA进行测序分型。结果:Ser/Cys杂合子个体的OR值为1.5,Cys/Cys纯合子个体的OR值为1.9,表现出剂量效应。结论:DNA修复基因hOGG1的Cys等位基因可能增加肝细胞肝癌的遗传易感性。

辐射耐受性宫颈癌细胞系的建立及DNA损伤修复相关基因的差异表达

目的筛选来源相同辐射耐受性不同的宫颈低分化鳞癌细胞DNA损伤修复相关基因的差异表达,探讨宫颈癌辐射耐受的机制。方法用9MeV-β射线反复多次间歇大剂量照射人宫颈低分化鳞癌细胞株SiHa,建立辐射耐受性细胞SiHaR,用DNA损伤修复相关PCR基因芯片检测SiHa与SiHaR差异表达基因,并对筛选出的部分基因进行Western blot验证。结果 SiHa及SiHaR细胞经射线照射后呈指数性杀灭,同一剂量照射后SiHaR细胞存活分数(survival fraction,SF)值更高,SiHaR细胞在2Gy照射后细胞存活分数(SF2)是SiHa的2.26倍;二者有差异表达的DNA损伤修复相关基因41个,其中上调基因27个,下调14个。有13个位点出现6倍以上或低于0.1的差异。Western blot对4个差异表达蛋白质验证结果提示,与SiHa细胞相比,糖尿病关联Ras相关基因(ras-related associated with diabetes,RRAD1)、复制因子C2[replication factor C(activator 1)2,RCF2]在SiHaR表达水平明显下调,而X线修复交叉互补基因1(X-ray repair complementing defective repair,XRCC1)及切除修复交叉互补基因(excision repair cross-complementing,ERCC1)蛋白质明显上调。结论人宫颈癌细胞系SiHa经间歇性大剂量射线多次照射后筛选获得的SiHaR细胞具有稳定的辐射耐受性;这与DNA损伤修复能力在基因水平上发生了某些突变明显相关。这为通过调控相关基因进行放射敏感性调控提供了依据。