Telomere length and telomerase catalytic subunit expression in non-astrocytic gliomas.
Telomerase activation has been implicated as a major factor in the development of cancer. In our previous study we reported on the telomerase activity of a variety of gliomas. To further investigate the role of telomere and telomerase regulation in the pathogenesis of non-astrocytic gliomas, we examined the telomere length and the mRNA expression of telomerase reverse transcriptase gene (hTERT) and telomerase-associated protein (hTEP) in a series of 27 oligodendroglial and 18 ependymal tumors in this study. No statistical difference was found between the mean telomere length in telomerase-positive and telomerase-negative tumors (11.5 kb vs 13.1 kb; p = 0.424), although a slightly shorter length was observed in telomerase-positive oligodendroglial tumors. mRNA expression of hTERT was highly correlated with the telomerase activity status. hTERT was expressed in 8/8 (100%) and 2/2 (100%) telomerase-positive oligodendroglial and ependymal tumors, respectively, whereas 3/6 (50%) telomerase-negative oligodendroglial tumors and no telomerase-negative ependymal tumors showed expression. In contrast, hTEP1 mRNA was widely expressed in both telomerase-positive and telomerase-negative oligodendroglial and ependymal tumors. Our data support the notion that hTERT plays a critical role in determining the enzymatic activity of human telomerase. It has recently been proposed that both p16(INK4)/Rb pathway inactivation and telomerase activity were required for immortalization of epithelial cells. Although lack of p(16INK4a) expression was detected in a substantial proportion of tumors, no correlation between the p16(INK4a) or pRb protein expression and telomerase activity was observed in our series of non-astrocytic tumors.
Chong EYY
Department of Anatomical and Cellular Pathology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong.
Pang JCS
Ko
C W
CW
Poon
W S
WS
Ng
H K
HK
D000293:Adolescent; D000328:Adult; D000368:Aged; D002352:Carrier Proteins / Q000235:genetics; D002384:Catalysis; D016543:Central Nervous System Neoplasms / Q000201:enzymology* / Q000378:metabolism / Q000648:ultrastructure*; D002648:Child; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000378:metabolism; D004268:DNA-Binding Proteins; D005260:Female; D005910:Glioma / Q000201:enzymology* / Q000648:ultrastructure*; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D012313:RNA; D012333:RNA, Messenger / Q000378:metabolism; D016601:RNA-Binding Proteins; D016160:Retinoblastoma Protein / Q000378:metabolism; D019098:Telomerase / Q000235:genetics / Q000378:metabolism*; D016615:Telomere / Q000648:ultrastructure*
D002352:Carrier Proteins; D019941:Cyclin-Dependent Kinase Inhibitor p16; D004268:DNA-Binding Proteins; D007527:Isoenzymes; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D016160:Retinoblastoma Protein; C104342:TEP1 protein, human; C422952:telomerase RNA; D012313:RNA; D019098:Telomerase