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) G f0 a1 Q: I& j/ u7 bNaked mole rats are remarkable in
" k% ?- G5 W8 c. i. f8 K/ P. zcombining extreme longevity with virtually complete resistance to cancer. Now a " |4 G4 Z! g# f T# N& I( l3 s
novel glycosaminoglycan variant that may have evolved to provide the creatures
1 s" \: n6 \8 gwith the tough, flexible skin needed for a subterranean lifestyle has been
, x6 ^$ L0 S, A5 F+ L+ Aidentified as a key contributor to their cancer resistance. Hyaluronan, or / o3 a4 q# x$ ^) H' { c
hyaluronic acid, is a ubiquitous component of the extracellular matrix. Xiao
" u# {6 C. r9 c0 y P! H: U+ ATian et al. observed that the culture media of naked mole-rat ) i1 E; \& l5 K9 e$ M9 P
fibroblasts becomes viscous owing to the accumulation of a thick ‘gooey’
}8 K3 v$ c0 B4 A$ Usubstance and identified it as a high-molecular-mass hyaluronan (HMM-HA), more ( H# f, A9 J: y) Q7 b; E- t& F
than five times larger than mouse and human equivalents. It accumulates in naked
: F" p$ b z4 K/ s f' wmole-rat tissues owing to low hyaluronidase activity and a unique form of
4 C' _* z* j2 \% Lhyaluronan synthase 2. HMM-HA acts through the CD44 receptor and removal of 4 [/ E; {+ n5 j- c, l" p2 R
HMM-HA makes naked mole-rat cells more susceptible to transformation. This
) t8 W/ e4 p5 K+ r# k* B2 O5 ~unusual model of cancer protection suggests potential new avenues of research
/ r% W) x2 Z, winto anticancer and life-extension strategies. Cover: Joel Sartore/National o7 a y3 m) a D# e3 l. c% |
Geographic Image Collection/Alamy3 y9 k; {/ [* ?: F0 X
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发表于 2013-7-19 19:33
发表于 2013-7-19 19:42
