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- 积分
- 17983
- 威望
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- 包包
- 26159
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7 ^! k% |8 A0 h9 R% y3 ]0 M1 k( wNaked mole rats are remarkable in & s4 Q/ f% y! x, Y* K5 q$ j
combining extreme longevity with virtually complete resistance to cancer. Now a
" J7 u" d& k% H. Onovel glycosaminoglycan variant that may have evolved to provide the creatures & m0 |+ Y' ]7 z( P
with the tough, flexible skin needed for a subterranean lifestyle has been
% ]: y7 p4 u/ @6 h+ B8 pidentified as a key contributor to their cancer resistance. Hyaluronan, or
1 o$ }6 |, C+ r' v, Chyaluronic acid, is a ubiquitous component of the extracellular matrix. Xiao
) P+ v3 X" ~& O& f- o3 {Tian et al. observed that the culture media of naked mole-rat * l- [- l3 f! @1 D( `: b
fibroblasts becomes viscous owing to the accumulation of a thick ‘gooey’
: y2 |: Z% a6 R/ O0 ?substance and identified it as a high-molecular-mass hyaluronan (HMM-HA), more
' D8 F v9 q" {, O; Y6 P# Z* w+ pthan five times larger than mouse and human equivalents. It accumulates in naked " @' h( t2 d0 W
mole-rat tissues owing to low hyaluronidase activity and a unique form of $ \) S3 o, r6 U' j
hyaluronan synthase 2. HMM-HA acts through the CD44 receptor and removal of 1 n0 L5 c2 C9 k' G9 R
HMM-HA makes naked mole-rat cells more susceptible to transformation. This
1 G+ z. i4 j- [0 a# e7 Uunusual model of cancer protection suggests potential new avenues of research . \: {5 G# ^$ p: J
into anticancer and life-extension strategies. Cover: Joel Sartore/National
3 V+ D" g" B; I: vGeographic Image Collection/Alamy( _1 i9 f/ @3 Y: K6 c5 c
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发表于 2013-7-19 19:33
发表于 2013-7-19 19:42
