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Naked mole rats are remarkable in / T; s; s8 q7 ]( G& G6 V& u
combining extreme longevity with virtually complete resistance to cancer. Now a
1 t! N. Z# \( y# ?4 x A/ ]novel glycosaminoglycan variant that may have evolved to provide the creatures
8 ~4 U0 y; g) I4 @( n+ M$ lwith the tough, flexible skin needed for a subterranean lifestyle has been ) E/ A- D% p6 R; U5 A4 C4 U3 i; d+ C
identified as a key contributor to their cancer resistance. Hyaluronan, or
' E; F. Q/ d$ g9 x9 U- d1 hhyaluronic acid, is a ubiquitous component of the extracellular matrix. Xiao + h* s' g' W& i5 k0 }
Tian et al. observed that the culture media of naked mole-rat
. E) M1 | R) `fibroblasts becomes viscous owing to the accumulation of a thick ‘gooey’
& P) w* [1 [: b9 n! P9 n5 R- h( Z: msubstance and identified it as a high-molecular-mass hyaluronan (HMM-HA), more
) T! o- H. K3 g; }4 bthan five times larger than mouse and human equivalents. It accumulates in naked
! u6 }+ B$ M' M+ |! b7 x+ @0 ~* cmole-rat tissues owing to low hyaluronidase activity and a unique form of 0 }6 ^" M2 G' A) O; }4 o
hyaluronan synthase 2. HMM-HA acts through the CD44 receptor and removal of " l/ H8 Y! l/ b8 t; {0 s, P( C
HMM-HA makes naked mole-rat cells more susceptible to transformation. This
; T' d; H0 K% C. a: f- munusual model of cancer protection suggests potential new avenues of research : T7 `% y, A9 X
into anticancer and life-extension strategies. Cover: Joel Sartore/National 5 F2 Z3 d) m; Z4 ^" \9 `2 i
Geographic Image Collection/Alamy
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发表于 2013-7-19 19:33
发表于 2013-7-19 19:42
