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Naked mole rats are remarkable in ( X4 C, X; d* K) E- Z
combining extreme longevity with virtually complete resistance to cancer. Now a
2 y8 ] p- U3 ]5 ?! f, F6 snovel glycosaminoglycan variant that may have evolved to provide the creatures - I6 P# _5 d' H7 [) W& G3 G
with the tough, flexible skin needed for a subterranean lifestyle has been
- A$ @& [& g7 K. K% @identified as a key contributor to their cancer resistance. Hyaluronan, or
+ T- J6 I$ u' Zhyaluronic acid, is a ubiquitous component of the extracellular matrix. Xiao 4 I3 E( f; C' k8 b+ @! _: K
Tian et al. observed that the culture media of naked mole-rat 9 K0 h8 o9 |& [& \" R: P) f
fibroblasts becomes viscous owing to the accumulation of a thick ‘gooey’ - ~. u" ~- s9 d G. I
substance and identified it as a high-molecular-mass hyaluronan (HMM-HA), more , H9 _5 z( Q+ D% T1 `+ e: m. ^
than five times larger than mouse and human equivalents. It accumulates in naked
; Y* M6 w7 a$ w8 j2 [9 |mole-rat tissues owing to low hyaluronidase activity and a unique form of 5 n6 _# N7 J8 q1 D9 n
hyaluronan synthase 2. HMM-HA acts through the CD44 receptor and removal of 9 u* |7 e, p$ X" K
HMM-HA makes naked mole-rat cells more susceptible to transformation. This ! v C A" a$ l! N. ?: k, _
unusual model of cancer protection suggests potential new avenues of research
t. t: u8 w2 ]6 ~# Zinto anticancer and life-extension strategies. Cover: Joel Sartore/National 7 v8 o7 t# B9 W
Geographic Image Collection/Alamy
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发表于 2013-7-19 19:33
发表于 2013-7-19 19:42
