基因突变与结肠癌发展的关系
文章来源:未知 文章作者:enread 发布时间:2012-06-08 05:30 字体: [ ]  进入论坛
(单词翻译:双击或拖选)

In exploring the genetics of mitochondria(线粒体) -- the powerhouse of the cell -- researchers at Fred Hutchinson Cancer Research Center have stumbled upon a finding that challenges previously2 held beliefs about the role of mutations in cancer development. For the first time, researchers have found that the number of new mutations are significantly lower in cancers than in normal cells.

"This is completely opposite of what we see in nuclear DNA4, which has an increased overall mutation3 burden in cancer," said cancer geneticist Jason Bielas, Ph.D., whose findings are published in the June 7 issue of PLoS Genetics.

Mutations are changes in the genetic1 sequence of a cell's genome and can occur as a result of environmental exposure to viruses, radiation and certain chemicals, or due to spontaneous errors during cell division or DNA replication.

Mitochondria, which are primarily responsible for the cell's energy production, are semi-autonomous; similar to the nucleus5, they have their own set of DNA, which encodes genes6 critical for the functioning of the cell. While the role of genomic instability has been well characterized in nuclear DNA, this is the first attempt to determine whether instability in mitochondrial DNA may play a similar role in cancer growth and metastasis(新陈代谢) .

"We were surprised to find that the frequency of new mutations in mitochondrial DNA from tumor7 cells is decreased compared to that of normal cells," said Bielas, an assistant member of the Public Health Sciences and Human Biology divisions at the Hutchinson Center. "By extension, this suggests, somewhat counterintuitively, that higher mitcochondrial mutation rates may actually serve as a barrier to cancer development, and drugs that focus directly on increasing mitochondrial DNA damage and mutation might swap8 cancer's immortality9 for accelerated aging and tumor-cell death."

For the study, the researchers used using an ultra-sensitive test to detect mutations in mitochondrial DNA from normal and cancerous colon10 tissue resected from 20 patients prior to chemotherapy.

Bielas and colleagues first set out to analyze11 mutation rates in mitochondrial DNA because they wanted to see if it could act as a surrogate(代用品) for nuclear DNA as a cancer biomarker. "Cells contain a thousandfold more mitochondrial genetic material than nuclear DNA, so theoretically you'd need a thousand times less tissue to get the same genetic information to predict clinical outcomes such as how fast a tumor would progress or whether it would be resistant12 to therapy," Bielas said.

While mitochondrial DNA proved to be an unreliable stand-in for nuclear DNA as a cancer biomarker, it offers promise as a new drug target.

"If we could increase DNA damage and mutation within the mitochondrial genome, theoretically we could decrease cancer," Bielas said. "That's what we're testing now. This is a whole new hypothesis."



点击收听单词发音收听单词发音  

1 genetic PgIxp     
adj.遗传的,遗传学的
参考例句:
  • It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
  • Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。
2 previously bkzzzC     
adv.以前,先前(地)
参考例句:
  • The bicycle tyre blew out at a previously damaged point.自行车胎在以前损坏过的地方又爆开了。
  • Let me digress for a moment and explain what had happened previously.让我岔开一会儿,解释原先发生了什么。
3 mutation t1PyM     
n.变化,变异,转变
参考例句:
  • People who have this mutation need less sleep than others.有这种突变的人需要的睡眠比其他人少。
  • So far the discussion has centered entirely around mutation in the strict sense.到目前为止,严格来讲,讨论完全集中于围绕突变问题上。
4 DNA 4u3z1l     
(缩)deoxyribonucleic acid 脱氧核糖核酸
参考例句:
  • DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
  • Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。
5 nucleus avSyg     
n.核,核心,原子核
参考例句:
  • These young people formed the nucleus of the club.这些年轻人成了俱乐部的核心。
  • These councils would form the nucleus of a future regime.这些委员会将成为一个未来政权的核心。
6 genes 01914f8eac35d7e14afa065217edd8c0     
n.基因( gene的名词复数 )
参考例句:
  • You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因,所以能够活得很长。 来自《简明英汉词典》
  • Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪
7 tumor fKxzm     
n.(肿)瘤,肿块(英)tumour
参考例句:
  • He was died of a malignant tumor.他死于恶性肿瘤。
  • The surgeons irradiated the tumor.外科医生用X射线照射那个肿瘤。
8 swap crnwE     
n.交换;vt.交换,用...作交易
参考例句:
  • I will swap you my bicycle for your radio.我想拿我的自行车换你的收音机。
  • This comic was a swap that I got from Nick.这本漫画书是我从尼克那里换来的。
9 immortality hkuys     
n.不死,不朽
参考例句:
  • belief in the immortality of the soul 灵魂不灭的信念
  • It was like having immortality while you were still alive. 仿佛是当你仍然活着的时候就得到了永生。
10 colon jqfzJ     
n.冒号,结肠,直肠
参考例句:
  • Here,too,the colon must be followed by a dash.这里也是一样,应当在冒号后加破折号。
  • The colon is the locus of a large concentration of bacteria.结肠是大浓度的细菌所在地。
11 analyze RwUzm     
vt.分析,解析 (=analyse)
参考例句:
  • We should analyze the cause and effect of this event.我们应该分析这场事变的因果。
  • The teacher tried to analyze the cause of our failure.老师设法分析我们失败的原因。
12 resistant 7Wvxh     
adj.(to)抵抗的,有抵抗力的
参考例句:
  • Many pests are resistant to the insecticide.许多害虫对这种杀虫剂有抵抗力。
  • They imposed their government by force on the resistant population.他们以武力把自己的统治强加在持反抗态度的人民头上。
TAG标签: genetic DNA cell
发表评论
请自觉遵守互联网相关的政策法规,严禁发布色情、暴力、反动的言论。
评价:
表情:
验证码:点击我更换图片