Telomere length and telomerase activity in canine mammary gland tumors.
OBJECTIVE
To measure telomere length and telomerase activity in naturally occurring canine mammary gland tumors.


METHODS
27 mammary gland tumor specimens obtained during resection or necropsy and 12 mammary gland tissue specimens obtained from healthy (control) dogs.


METHODS
Telomere length in tissue specimens was measured by use of restriction endonuclease digestion and Southern blot analysis. Telomerase activity was measured by use of a telomeric repeat amplification protocol assay.


RESULTS
Telomere length in mammary gland tumors ranged from 11.0 to 21.6 kilobase pairs (kbp; mean +/- SEM, 14.5+/-0.5 kbp) but did not differ among tumor types. Telomeres in mammary gland tumors were slightly shorter than in normal tissue specimens, but telomere length could not be directly compared between groups, because mean age of dogs was significantly different between groups. Age was negatively correlated with telomere length in control dogs but was not significantly correlated with length in affected dogs. Telomerase activity was detected in 26 of 27 mammary gland tumors and in 4 of 12 normal tissue specimens. However, telomerase activity and telomere length were not correlated in tumor specimens.


CONCLUSIONS
Telomere length is maintained in canine mammary gland tumors regardless of the age of the affected dog. Measurement of telomere length may be a useful tool for monitoring the in vivo effects of telomerase inhibitors in dogs with tumors.
Yazawa
M
M
Department of Veterinary Internal Medicine, Graduate School of Agricultural and Life Sciences, University of Tokyo, Japan.
Okuda
M
M
Setoguchi
A
A
Iwabuchi
S
S
Nishimura
R
R
Sasaki
N
N
Masuda
K
K
Ohno
K
K
Tsujimoto
H
H
D000230:Adenocarcinoma / Q000201:enzymology / Q000235:genetics / Q000662:veterinary; D000236:Adenoma / Q000201:enzymology / Q000235:genetics / Q000662:veterinary; D000818:Animals; D015139:Blotting, Southern; D004262:DNA Restriction Enzymes / Q000737:chemistry; D004273:DNA, Neoplasm / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D004195:Disease Models, Animal; D004283:Dog Diseases / Q000201:enzymology* / Q000235:genetics*; D004285:Dogs; D005260:Female; D008297:Male; D015674:Mammary Neoplasms, Animal / Q000201:enzymology* / Q000235:genetics*; D009208:Myoepithelioma / Q000201:enzymology / Q000235:genetics / Q000662:veterinary; D019098:Telomerase / Q000235:genetics / Q000378:metabolism*; D016615:Telomere / Q000235:genetics*
D004273:DNA, Neoplasm; D019098:Telomerase; D004262:DNA Restriction Enzymes