Effect of Bcl-2 Expression and Telomerase Activity on Apoptosis of the Brain Tumors

Kim, Choong Hyun; Cheong, Jin Hwan; Bak, Koang Hum; Kim, Jae Min; Ko, Yong; Oh, Suck Jun

Abstract

OBJECTIVE
The regulation of apoptosis is influenced by various gene products including Bcl-2, which has been known to be anti-apoptotic. In addition, telomerase, a ribonucleoprotein that synthesizes telomeres, has been detected in many human neoplasms. In the current study, we present the anti-apoptotic effect by Bcl-2 expression and telomerase activity in the human brain tumors.
METHODS
A total of 76 cases of surgically resected brain tumors were studied. Telomerase activity was detected by the telomeric repeat amplification protocol assay and Bcl-2 protein was examined by the Western blot analysis. Apoptosis of the specimens was also detected by DNA fragmentation analysis.
RESULTS
Telomerase activity and apoptosis were detected in 65.8%(50 of 76) and 21.1%(16 of 76) respectively. Telomerase activity was correlated to apoptosis inversely(p<0.05). Bcl-2 was also expressed in 23.7%(18 of 76) and apoptosis detected in 11.1%(2 of 18) with Bcl-2. In 18 cases with Bcl-2, telomerase activity was expressed in 77.8%(14 of 18) and apoptosis was not induced in 85.7%(12 of 14) with telomerase activity. However, apoptosis was not detected in 4 cases with Bcl-2 and negative telomerase activity. Their difference of anti-apoptotic numbers between two groups was significant(p<0.05). In 36 cases with negative Bcl-2 and positive telomerase activity, apoptosis was not detected in 72.2%(26 of 36). In 22 cases without Bcl-2 and telomerase activity, apoptosis was not detected in 81.8%(18 of 22). Their difference between two groups was not significant statistically.
CONCLUSION
Our results suggest that apoptosis may be modulated by telomerase activity of the human brain tumors with Bcl-2. And also, we may expect that apoptosis can be induced effectively by the inhibition of telomerase activity and Bcl-2 in the brain tumors.