Normal Stem Cells and Cancer Stem Cells: The Niche Matters

饶冠华

Normal Stem Cells and Cancer Stem Cells: The Niche Matters
" R: G3 ]1 V* r0 Z' `- FLinheng Li1,3 and William B. Neaves1,2 " [% v. n- h, t% f" A" K
1 Stowers Institute for Medical Research and 2 University of Missouri-Kansas City School of Medicine, Kansas City, Missouri and 3 University of Kansas Medical Center, Kansas City, Kansas
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Requests for reprints: Linheng Li, Stowers Institute for Medical Research, Kansas City, MO. E-mail: lil@stowers-institute.org.
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, z* C! A8 r9 T5 Q3 q% B  H, sScientists have tried for decades to understand cancer development in the context of therapeutic strategies. The realization that cancers may rely on "cancer stem cells" that share the self-renewal feature of normal stem cells has changed the perspective with regard to new approaches for treating the disease. In this review, we propose that one of the differences between normal stem cells and cancer stem cells is their degree of dependence on the stem cell niche, a specialized microenvironment in which stem cells reside. The stem cell niche in adult somatic tissues plays an essential role in maintaining stem cells or preventing tumorigenesis by providing primarily inhibitory signals for both proliferation and differentiation. However, the niche also provides transient signals for stem cell division to support ongoing tissue regeneration. The balance between proliferation-inhibiting and proliferation-promoting signals is the key to homeostatic regulation of stem cell maintenance versus tissue regeneration. Loss of the niche can lead to loss of stem cells, indicating the reliance of stem cells on niche signals. Therefore, cancer stem cells may arise from an intrinsic mutation, leading to self-sufficient cell proliferation, and/or may also involve deregulation or alteration of the niche by dominant proliferation-promoting signals. Furthermore, the molecular machinery used by normal stem cells for homing to or mobilizing from the niche may be "hijacked" by cancer stem cells for invasion and metastasis. We hope this examination of the interaction between stem cells and their niche will enhance understanding of the process of cancer development, invasiveness, and metastasis and reveal possible targets for cancer treatment. (Cancer Res 2006; 66(9): 4553-7)
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marrowstem

great idea. 个人认为这是理解肿瘤发生与干细胞之间可相关联的一座桥梁。, ^, [0 `/ X3 I9 \, @. `* o
而与这座桥相通的路可能是通向罗马的一条正道。& @# W* j9 q- n6 A& C! @
可归结为一句话的原因是：正常干细胞在异常niche中的不正常发育是肿瘤得以发生的一个重要原因。

mckf111

唯物辩证法告诉我们内因是主导 外因是条件 对于cancer的generation和progression来说 niche是外因 所以它最多是matters而不会determines
/ i; @* D, w/ P  N1 G# u这里有个进一步的思考 就是细胞欲发生癌变之初 细胞可否根据自身的需要 主动改变自己的niche 进而促进肿瘤形成 这样更能够说明其只是matters

marrowstem

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$ k+ s( E& |9 x1 G; H虽然从遗传学角度来说，“种瓜得瓜、种豆得豆”这句谚语没错，但对干细胞的生物学行为来说，可能“橘生江南则为桔，生于江北则为枳”这句谚语来得更有道理。而niche 就是干细胞的生长环境，有很多时候，外因改变了干细胞的生物学的行为。
' S& B0 n' R1 ~, w干细胞能主动改变自己的niche吗？个人表示否定。( V% e+ \' G1 s$ ?7 ?, v
那么niche又是怎样改变自己的呢？还是更外的外因促成，如炎症感染、衰老等等的诱因，导致机体不能完全修复原来的组织结构，从而导致异常的niche得以形成。

mckf111

回复 4# marrowstem : m  b$ B5 o8 C& o- p; l, [
“橘生江南则为桔，生于江北则为枳”并非“生江南则为桔，生于江北则为枳”% u# a8 I) ?/ Y/ f% u9 t) }, K% o% o
“干细胞能主动改变自己的niche吗？”——nothing is impossible especially in science

marrowstem

回复 5# mckf111
  \! F' D& c: q& I0 G1 F你的回答等于没回答，说点有用的。

tainlangxing

呵呵~~不错的好文章，正需要那~就是不知道此语境中niche该如何解释，还请赐教~

marrowstem

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; l4 r0 Y6 c  w- W( r( xniche是干细胞居住的家，是孵育生命的源泉所在地。而对于一已是恶性性质的niche来说，则意味着是一个潘多拉的盒子，里面孵育出来的是一个个魔鬼癌细胞。

marrowstem

niche这个词有多种含义，从解剖结构角度来看，niche的意思是隐窝（recess)；从生态学角度来看，他意味着是一个能繁衍后代的住所（habitat)；而在法语中他的意思又是一dog-house.
6 c' T( W, @: t$ A- x) ?! n. a+ S  Q翻译成中文，niche的意思是壁龛，专门用来放置观音或关公等圣物的墙壁凹入处。

wzx6660

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