Tumoral cell mtDNA approximately 8.9 kb deletion is more common than other deletions in gastric cancer

BACKGROUND: The aim of the study was to clarify the role of deletion of mitochondrial DNA (mtDNA) in gastric carcinogenesis and to determine prevalence of mitochondrial deletions in different regions of tumoral tissue in comparison with adjacent non-tumoral tissue in gastric cancer. METHODS: In order to investigate whether a high incidence of mutations exists in mtDNA of gastric cancer tissues, we screened five regions of the mitochondrial genome by PCR amplification, Southern blot and DNA sequence analysis. RESULTS: Of 71 cancer patients, the approximately 8.9 kb deletion was detected among different deletions in 9 cases (12.67%) of the tumoral tissues and 1 case (1.40%) in non-tumoral tissues that were adjacent to the tumors. Level of the 8.9 kb deletion has been found to be more than other deletions in tumoral tissues. CONCLUSIONS: The approximately 8.9 kb deletion has an obvious correlation with age and histological type. These data suggest that the approximately 8.9 kb deletion in mtDNA may play an important role in gastric carcinogenesis.     

人颗粒细胞线粒体DNA缺失的研究

目的 探讨颗粒细胞线粒体DNA突变在女性生殖老化中的可能机制，并为颗粒细胞线粒体移植提供理论基础。方法 分离70例临床行常规体外受精(IVF)和胞质内单精子注射(ICSI)患者的颗粒细胞，抽提DNA，PCR检测颗粒细胞线粒体DNA(mitochondrial DNA，mtDNA)4977bp缺失情况。结果所有颗粒细胞均未检测到mtDNA4977bp缺失。结论 人颗粒细胞mtDNA并不发生4977bp缺失．这可能与其不是有丝分裂后细胞，仍具有增殖能力，受到的氧化损伤较少有关。颗粒细胞参与生殖老化的机制可能与其mtDNA突变无关。     

线粒体DNA4977bp缺失检测肿瘤细胞辐射敏感性的初步研究

目的:探讨mtDNA4977bp缺失用于肿瘤细胞辐射敏感性检测的可行性。方法:分别采用MTT法和巢式PCR法测定人肿瘤细胞株—肝癌细胞(HepG2)、食管癌细胞(EC-9706)和乳腺癌细胞(MCF-7)不同剂量γ射线照射后的存活分数(SF)和mtDNA4977bp缺失率。结果:MTT法:2Gy、4Gy和8Gy照射后,HepG2和EC-9706的SF显著低于MCF-7,表明HepG2和EC-9706细胞具有更高的辐射敏感性,HepG2细胞照射后的SF略低于EC-9706细胞,但统计学差异不显著。PCR法:1Gy和4Gy照射后3种肿瘤细胞mtDNA4977bp缺失率无显著性差异。8Gy照射后HepG2和EC-9706 mtDNA4977bp缺失进一步增加,而MCF-7的缺失率下降,显著低于HepG2与EC-9706细胞的缺失率,但HepG2和EC-9706细胞的缺失率无统计学差异,提示HepG2和EC-9706细胞的辐射敏感性高于MCF-7细胞,这与MTT法测定结果相符。结论:测定mtDNA4977bp缺失作为快速、简便的检测方法,有望用于肿瘤细胞辐射敏感性预测。     

结直肠癌线粒体DNA拷贝数改变及4977片段缺失

目的 探讨结直肠癌（colorectal cancer,CRC）线粒体DNA（mitochondrial DNA,mtDNA）拷贝数异常、线粒体DNA 4 977 bp大片段缺失与TNM分期和分化程度的关系.方法 选取118例石蜡标本大肠癌组织,分别提取总DNA.以ND1和β-actin为目的基因,进行SYBR Green荧光定量PCR扩增,并用PCR扩增方法检测4 977片段缺失情况,探讨它们与不同TNM分期和分化程度之间的关系.结果 CRCⅠ和Ⅱ期癌组织平均拷贝数（2ND1/β-actin）分别为128.42±31.25和115.12±47.15,Ⅲ和Ⅳ期癌组织平均拷贝数为105.22±16.35和99.45±28.46.Ⅰ和Ⅱ期的拷贝数明显高于Ⅲ和Ⅳ期的拷贝数（P〈0.01）,癌组织低、中、高分化的平均拷贝数分别为101.34±41.35、112.33±42.32和127.22±31.23（P〈0.01）,4 977片段缺失率为15.25%（18/118）,线粒体DNA4977bp缺失与患者的分期呈负相关,与分化程度无明显关系.结论 线粒体DNA 4 977 bp缺失在大肠癌的早期阶段起到了重要作用,随着肿瘤的进展,拷贝数逐渐减少,线粒体DNA拷贝数的变化及大片段缺失在肿瘤的发病机制中可能起一定作用.     

Mutations in the D-loop region of mitochondrial DNA in g astric cancer

Objective: To investigate the mutations in the D-loop region of mitochondrial DNA (mtDNA) in gastric cancer.Methods: The mtDNA of D-loop region was amplified by PCR and ,sequenced in 20 samples from gastric cancer tissue and adjacent normal membrane. Results: There were 7/20(35% ) mutations in the mtDNA of D-loop region in gastric cancer patients. There were four microsatellite instabilities among the 18 mutations. Nine new polymorphisms were identified in 20 patients. Conclusion: The mtDNA of D-loop region might be highly polymorphoric and the mutation rate is high in patients with gastric cancer.     

2 型糖尿病患者线粒体常见基因突变PCR检测的局限性

目的:研究北京地区汉族人群中线粒体DNA(m itochondrial DNA,m tDNA)多位点突变频率与2型糖尿病之间的相关性。方法:采用直接PCR、PCR-限制性片段长度多态性(restriction fragm ent length polymorph ism,RFLP)、PCR-时相温度梯度凝胶电泳(temporal temperature grad ient gel electrophoresis,TTGE)法筛查m tDNA 4977片段缺失、线粒体tRNALeu(UUR)A3243G突变和m tDNA T14577C突变。结果:在250例2型糖尿病患者及142例健康对照外周血基因组总DNA中,未发现m tDNA 4977缺失、线粒体tRNALeu(UUR)A3243G突变及m tDNA T14577C突变。结论:m tDNA 4977缺失、线粒体tRNALeu(UUR)A3243G突变及m tDNA T14577C突变在外周血中没有检出,采用常规PCR法检测2型糖尿病患者外周血线粒体DNA突变具有较大的局限性。     

Mitochondrial gene defect in patients with chronic progressive external ophthalmoplegia

Objective To detect the gene defect of mitochondrial DNA(mtDNA) from skeletal muscles in 2 patients with chronic progressive external ophthalmoplegia (CPEO).Methods After extraction of mtDNA, Southern hybridization was performed after restrictive digestion by PvuⅡ, EcoRI, Hind Ⅲ, and SacI. Then, we carried out polymerase chain reaction(PCR) and the enzyme digestion of the PCR products. Finally, mtDNA sequencing was done by automatic DNA sequence analyzer. Results In case 1, a 5 kb deletion was found by Southern blot analysis and PCR. And dosage analysis showed a heteroplasmic change with 44% mtDNAs deleted. In case 2, PCR plus restriction endonuclease PvuⅡ digestion demonstrated a mutation which was confirmed by DNA sequencing to be a single base substitution (T→C) inducing a novel PvuⅡ site around 10909 on mtDNA sequence. The laser image analyzer measurement revealed the mutation was almost homologous (99.4% mutant).Conclusions In case 1, a 5 kb deletion found in mtDNA is called "common deletion" according to the literature. In case 2, a novel PvuⅡ site was found. It seems to be a de novo point mutation affecting ND4 in published CPEO research and is first reported in Chinese population. This point mutation does not induce an amino acid(Phe) change according to the published human mitochondrial genetic code as well as the mtDNA sequence. Whether it affects the translation efficiency or transportation of signals between mitochondrial and nuclear genome needs further studies.     

人外周血细胞线粒体DNA中存在特大片段缺失突变

了解线粒体ＤＮＡ大片段缺失突变及其意义。方法采用６种方法提取人外周血细胞ＤＮＡ,,其中１种方法先分离线粒体,再抽提线粒体ＤＮＡ。以得到的人外周血细胞ＤＮＡ为模板进行ＰＣＲ扩增,其产生经琼脂糖凝胶回收后与ｐＧＥＭ－Ｔ载体连接、转化、测序。结果６种方法抽提ＤＮＡ进行ＰＣＲ扩增后,产物电泳行为相同,发现人血细胞线粒体ＤＮＡ存在１３１６２ｂｐ特大片段缺失突变。结论此缺失首首发现的,经测序证明为人线粒体ＤＮ     

胃癌细胞系和胃癌组织中线粒体DNA4 977 bp缺失及其生物学意义

目的 明确线粒体DNA 4977bp大片段缺失在胃癌细胞系、胃癌组织及胃癌患者血清中的频率,为胃癌的早期临床诊断寻找简便准确的分子标记。方法 运用Primer-shift PCR和直接测序的方法对13个胃癌细胞系、52对胃癌组织及对应的癌旁正常组织（年龄从28-78岁）、40例胃癌患者血清及40名正常人血清进行筛查。取10例胃癌组织的石蜡切片,采用显微切割技术在同一患者的切片上同时分离3种组织（包括胃粘膜正常腺体、肠化上皮及胃癌组织）对mtDNA 4977bp缺失进行了分析比较。结果 在13个胃癌细胞系中12个有mtDNA4977bp缺失（缺失率为92.3%),52例胃癌组织中38例有缺失（缺失率为73.1%),52例癌旁正常组织中27例有缺失（缺失率为52%）,40名胃癌患者血清中17例有缺失（缺失率为42.5%),40名正常人血清中8例有缺失（缺失率为20%）。胃癌组织和癌旁正常组织mtDNA 4977bp缺失差异有显著意义,癌组织mtDNA 4977bp缺失率与胃癌的分型和患者的性别没有关联。胃癌患者血清与正常人血清mtDNA4977bp缺失差异也有显著意义。10例显微切割组织中2例肠化上皮及胃癌组织中有缺失,而胃粘膜正常腺体未见缺失。结论 线粒体DNA 4977bp大片段缺失可能在胃癌发生和胃粘膜病变演化及细胞癌变的过程中起重要作用,血清中可以检测到线粒体DNA 4977bp大片段缺失,而且在胃癌患者血清中检出率远高于正常人血清。检测胃癌患者血清中mtDNA 4977bp大片段缺失有望成为一种简便易行的胃癌生物学行为的分子标记物。     

宣威地区非小细胞肺癌患者线粒体DNA突变与多态性研究

【目的】寻找宣威地区肺癌患者肺组织中线粒体DNA突变和多态性情况,为进一步研究宣威地区女性肺癌高发机制提供参考。【方法】征集28例宣威籍肺癌患者,收集癌组织和相应癌旁正常肺组织,提取线粒体DNA ,实时荧光定量PCR和直接测序方法检测线粒体DNA突变和多态性改变。【结果】28例肺癌组织样本同对应癌旁组织比较,有21例（75．0％）发生mtDNA突变,15例有多种突变,突变发生在DLOOP 区,以及呼吸链编码区等区域。突变与患者年龄、性别,及组织学类型无明显联系。28例肺癌组织、相应癌旁组织同M t-DNA剑桥序列比较,有3例有mtDNA多态性改变。【结论】宣威肺癌患者线粒体DNA存在特异性的突变位点,以及多态性位点,可能和当地特殊的燃煤污染暴露及遗传易感性有关。     

Cu/ZnSOD基因敲除小鼠耳蜗易于出现mtDNA缺失突变-ROS对组织损伤的特异性研究

目的　探讨ROS对各种组织mtDNA的损伤情况 ,耳蜗mtDNA是否为ROS损伤的标靶。方法　应用套式PCR及分子克隆测序技术对 10只Sod1基因敲除小鼠及 5只同系野生型小鼠耳蜗、脑、肝脏、肾脏、脾脏、心脏及皮肤组织进行研究。结果　 1 各组织mtDNA可检测到 3种缺失 ,常见的缺失为mtDNA386 7bp和mtDNA372 6bp缺失 ,mtDNA4 2 36bp缺失不常见。 2 mtDNA缺失在不同组织的含量有明显的不同 ,肝脏和肾脏组织含量最高 ,耳蜗、心脏和大脑组织其次 ,脾脏及皮肤组织含量最低。与野生型小鼠比较 ,Sod1基因敲除小鼠mtDNA在不同组织的缺失量是野生型小鼠的 3- 2 0倍 ,其中耳蜗组织mtDNA缺失量约是WT小鼠的 15倍。结论　缺乏Sod1的保护 ,ROS可以攻击各种组织mtDNA ,但具有明显的组织特异性 ,耳蜗mtDNA是其损害的敏感标靶。     

糖尿病线粒体ND1基因3316 G→A突变的功能研究

目的 探讨线粒体ND1基因3316 G→A突变对线粒体生物学功能的影响及其在糖尿病发病中的作用.方法 利用真核表达载体pcDNA3.1B和大肠杆菌DH5α构建野生型和线粒体DNA的ND1基因3316 G→A突变型重组子pcDNA3.1B-ND1;设计特异性siRNA序列干扰Hela细胞内源性线粒体DNA表达,使其内源性ND1基因沉默;经脂质体转入野生型和突变型重组子pcDNA3.1B-ND1,使其在Hela细胞内表达.通过RT-PCR、十二烷基硫酸钠-聚丙烯酰胺凝胶电泳和荧光显微镜,从mRNA水平→蛋白质水平→线粒体膜电势位检测干扰效果,以筛选有效干扰siRNA序列.结果 线粒体ND11和线粒体ND12 siRNA序列均具有一定的干扰效果,后者效果明显优于前者;转入3316 G→A突变型重组子pcDNA3.1B-ND1的Hela细胞表达的线粒体蛋白低于野生型.结论 线粒体DNA的ND1基因正常表达对维持正常的呼吸链功能和细胞增殖至关重要,携有3316 G→A突变基因的糖尿病的发病与线粒体蛋白表达下降有关.     

精索静脉曲张的不育病人精子线粒体DNA片段缺失的调查

目的分析精索静脉曲张导致的不育病人的精子线粒体DNA（mitochondrial DNA,mtDNA）中一个长为4 977 bp的片段缺失的情况。方法收集60例精索静脉曲张的不育病人和90名健康男性的精液标本,并抽提精子的总DNA,用Gap-PCR技术检测DNA 4 977 bp片段的缺失情况。结果在81.66%的患有精索静脉曲张的不育病人和4.44%的健康人对照中存在DNA 4 977 bp片段的缺失。患有精索静脉曲张的不育病人中DNA缺失频率更高（OR=139.80,95%CI=40.08~487.30,P < 0.01）。结论精索静脉曲张可能会导致一些男性精子DNA缺失,并导致不育。且精子线粒体DNA 4 977 bp片段缺失与精索静脉曲张所致不育症存在一定的相关性。     

线粒体DNA13731点突变与脊髓小脑性共济失调相关性研究

目的探索线粒体DNA（mtDNA）突变位点与脊髓小脑性共济失调（SCA）的关系。方法采用聚合酶链反应（PER）对基因确诊的四个SCA家系10例患者及其亲属共34例与40例健康对照的线粒体ND5基因片段进行扩增,扩增产物进行单链构象多态性分析（SSCP）,对SSCP出现异常的样本进行相应mtDNA片段测序。结果在一家系的1名确诊患者及1名症状前患者检测到mtDNA13731（T〉C）点突变。结论脊髓小脑性共济失调的发生、发展可能与mtDNA突变有关。     

Relationship between mutations of mitochondrial DNA ND1 gene and type 2 diabetes

Background Recent studies have indicated that many mutations in mitochondrial (mt)DNA NDI gene region are related to diabetes mellitus. In this study we explored the relationship between various mtDNA ND1 gene mutations and type 2 diabetes mellitus (DM) among Chinese. Methods Using PCR restriction fragment length polymorphism (PCR-RFLP) analysis and gene sequencing, 4 spots of mtDNA (nt3243, nt3316, nt3394, nt3426) were screened in 478 diabetics and 430 non-diabetic subjects.Results In diabetic group, there were 13 carriers (2.72%)of 3316 G→A mutation,12 (2.51%) of 3394 T→C mutation and 2 (0.42%) of 3426A→G mutation. In controls, only 3394 T→C mutation was observed in 2 subjects (0.47%). There was significant difference in the frequency of 3316 and 3394 mutation between two groups (P&lt;0.05, respectively). More subjects with mitochondrial DNA ND1 gene mutations had DM family history and greater tendency of maternal inheritance when compared to those patients without mutation in diabetic group（P&lt;0.01）. A 3426 mutation diabetic pedigree was studied, and we found 12 maternal members in the family had the same mutation. Conclusion mtDNA ND1 gene mutations at nt3316 (G→A), nt3394 (T→C) and 3426 (A→G) might contribute to the pathogenesis of DM with other genetic factors and environment factors.     

线粒体DNA ND4 12026基因突变与糖尿病

目的 研究线粒体DNADN412026位点在中国上海地区非肥胖2型糖尿病患者中的突变情况。并探讨该位点突变的临床特征。方法 采用PCR-SSCP、PCR-RFLP及PCR产物直接测序等技术检测线粒体DNAND4片段的突变情况。结果 发现286例糖尿病患者血样中有12例患者mtDNAND4基因上12026位点存在AtoG的点突变,导致异亮氨酸错义突变成缬氨酸,而在242例非糖尿病对照组个体中仅1例存在同样突变,对该位点突变的临床分析发现起病年龄低。58%有家族史,需要胰岛素治疗。结论 12026位点AtoG的突变可能与糖尿病的发生有关,并有一定的临床特征。     

胃癌线粒体DNA D-loop区碱基突变的检测分析

目的 研究胃癌患者的癌组织线粒体DNA （mtDNA）D-loop区碱基突变情况,以探讨mtDNA D-loop区碱基突变与胃癌发生发展的相关性.方法 采用聚合酶链反应和DNA测序相结合的方法,对75例胃癌患者癌组织线粒体D-loop 区进行扩增并测序分析.结果 在75例胃癌组织中共有130个位点发生了变化,其中属于基因多态性有101个,基因突变有29个.75例胃癌组织中39例mtDNA D-loop区存在突变,突变率为52%.结论 mtDNA D-loop 区碱基突变可能在胃癌发生发展中发挥重要作用.     

胃癌组织线粒体DNA D-loop区的突变及其意义

目的研究胃癌组织中线粒体DNA(mtDNA)D-loop区突变情况及其在肿瘤发生和发展中的作用。方法选择17例胃癌及相应正常胃黏膜组织,应用聚合酶链反应(PCR)对其mtDNA D-loop区进行扩增并测序,将测序结果与线粒体文库中的Revised Cambridge Reference Sequence(rCRS)进行对比分析。结果 17例胃癌组织中共发现mtDNA D-loop区存在175个多态性变异,其中8个(4.6%)为新发现的变异。8例(47.1%)胃癌组织中共发现13次突变;突变热点集中在HV1(23.1%)和HV2(53.9%),并且HV2较HV1更易突变。mtDNA D-loop区突变率与胃癌分化程度、浸润深度、有无淋巴结转移、病人性别和年龄无关(P>0.05)。结论 mtDNA D-loop区尤其是其中的HV1及HV2是一个具有高度多态性和突变性的区域,在胃癌中突变率较高。