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- 26159
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! Z! m! N- N0 q7 A; x2 LNaked mole rats are remarkable in
- l, v5 \. Y9 \2 z- v/ O1 lcombining extreme longevity with virtually complete resistance to cancer. Now a
: n' @$ k/ B; b$ a6 b1 mnovel glycosaminoglycan variant that may have evolved to provide the creatures
; B* V# s- o8 a- a7 P5 [8 ?2 s9 vwith the tough, flexible skin needed for a subterranean lifestyle has been 3 a% K7 k1 y9 w$ b
identified as a key contributor to their cancer resistance. Hyaluronan, or 5 U, R. g V& q8 Y$ a
hyaluronic acid, is a ubiquitous component of the extracellular matrix. Xiao
- U% A. ]5 p$ L2 |$ ]! J0 }+ k+ l6 ^Tian et al. observed that the culture media of naked mole-rat . R- U5 s+ l/ a/ p; ]2 Y- Y4 C z
fibroblasts becomes viscous owing to the accumulation of a thick ‘gooey’ % x( J( F2 {, f) J
substance and identified it as a high-molecular-mass hyaluronan (HMM-HA), more P z9 \# K1 y! S* B2 D
than five times larger than mouse and human equivalents. It accumulates in naked v6 J( D3 L# E1 ]' ?) H
mole-rat tissues owing to low hyaluronidase activity and a unique form of ! W/ R) S' m# i, ]; y9 o
hyaluronan synthase 2. HMM-HA acts through the CD44 receptor and removal of : ~2 k$ S2 j4 A, R6 l7 U
HMM-HA makes naked mole-rat cells more susceptible to transformation. This a, u- q! u! y1 |& K- M4 \
unusual model of cancer protection suggests potential new avenues of research $ i+ A7 F. R0 O0 H- b& \
into anticancer and life-extension strategies. Cover: Joel Sartore/National ' k; [* ]! P# v2 N
Geographic Image Collection/Alamy
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发表于 2013-7-19 19:33
发表于 2013-7-19 19:42
