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Naked mole rats are remarkable in
- y, T$ q+ U4 [ g7 p( ^' ?5 U+ Rcombining extreme longevity with virtually complete resistance to cancer. Now a
- @6 q X( i- Q/ Knovel glycosaminoglycan variant that may have evolved to provide the creatures 2 h( Y8 s, C; E0 I( a
with the tough, flexible skin needed for a subterranean lifestyle has been ! ?6 i5 F8 _6 }/ m5 C) U
identified as a key contributor to their cancer resistance. Hyaluronan, or # C! ~/ r s' R |; {
hyaluronic acid, is a ubiquitous component of the extracellular matrix. Xiao 7 p! L, _/ Z5 ?" y2 z4 _# i7 y
Tian et al. observed that the culture media of naked mole-rat
# n% \& P5 K8 lfibroblasts becomes viscous owing to the accumulation of a thick ‘gooey’ $ v9 E. i1 n" m6 l- m
substance and identified it as a high-molecular-mass hyaluronan (HMM-HA), more 0 ^; G( T6 `9 F- x0 v
than five times larger than mouse and human equivalents. It accumulates in naked
# { i" w F6 F E$ g omole-rat tissues owing to low hyaluronidase activity and a unique form of " P2 q( \" \0 H/ L
hyaluronan synthase 2. HMM-HA acts through the CD44 receptor and removal of
& Q+ R, M# b9 N- M, _8 LHMM-HA makes naked mole-rat cells more susceptible to transformation. This % O D. r# u* d8 Q+ X2 Q
unusual model of cancer protection suggests potential new avenues of research ' U) p: G8 q' D1 ^
into anticancer and life-extension strategies. Cover: Joel Sartore/National
+ p( M4 r. E7 F0 R* iGeographic Image Collection/Alamy
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发表于 2013-7-19 19:33
发表于 2013-7-19 19:42
