[Real-time quantitative RT-PCR for the detection of bcl-2 mRNA expression].

OBJECTIVE: To establish a real-time quantitative RT-PCR method for the detection of expression of bcl-2 mRNA. METHODS: The vector containing bcl-2 gene as standard template was constructed with T-A cloning technique. The fluorogenic probe (i.e.,Taq man probe) was used to establish a real-time RT-PCR. bcl-2 mRNA expression level in Burkitt's lymphoma pre-and post-treated with bcl-2 antisense phosphothioate oligodeoxynucleotides (AS-PS-ODN) was determined with real-time quantitative RT-PCR, also with semi-quantitative RT-PCR. RESULTS: The expression of bcl-2 mRNA in Burkitt's lymphoma treated with bcl-2 AS- PS-ODN decreased significantly and no changes of bcl-2-mRNA expression in group treated with nonsense ODN were noticed. The semi-quantitative RT-PCR results also demonstrated that bcl-2 level varied as detected with real-time fluorogenic quantitative RT-PCR, but less sensitive and accurate. CONCLUSION: Detection of bcl-2 mRNA expression with the fluorogenic real-time quantitative RT-PCR is more accurate and sensitive than semi-quantitive RT-PCR.

[New insight into the mechanism of p53 inducing leukemia cell apoptosis].

OBJECTIVE: To investigate the expression changes of intrinsic cytokines TGF-beta(1) and TNF-alpha, telomerase activity and bcl-2 during ongoing apoptosis of HL-60 and K562 cells induced by p53. METHODS: pN53cG (Val135), a temperature sensitive p53 mutant, which behaved like wild type p53 (wt-p53) at 32.5 degrees C, were introduced into p53-null HL-60 and K562 cells respectively by lipofectin. In the presence of G418, HL-60-pN53cG and K562 pN53cG clones expressing p53 protein were selected. The ongoing expression of intrinsic cytokines (TGF-beta(1) and TNF-alpha), bcl-2 oncogene and hTERT mRNA during the apoptosis of HL-60 and K562 cells induced by p53 and the effects of exogenous p53 gene, TGF-beta(1) and TNF-alpha antisense PS-ODNS on the apoptosis of HL-60 and K562 cells and the expression of bcl-2 were studied by RT-PCR, quantitative RT-PCR, DNA fragmentation, TdT-mediated dUTP nick end labeling (TUNEL) and flow cytometery. The levels of secreted TGF-beta(1) and telomerase activity were detected by ELISA and PCR-ELISA, respectively. RESULTS: (1) The expressions of intrinsic TGF-beta(1) and TNF-alpha mRNA were up-regulated, while that of bcl-2 and hTERT down-regulated. The levels of TGF-beta(1) in the supernatant of HL-60 and K562 cells were increased, and the level of telomerase activity decreased. (2) Antisense PS-ODNS of TGF-beta(1) and TNF-alpha could obviously inhibit the p53 inducing cell apoptosis, and restore bcl-2 mRNA and protein to pre-treated level. CONCLUSIONS: Exogenous p53 induces leukemia cell apoptosis via up-regulating the expression of intrinsic TGF-beta(1) and TNF-alpha and down-regulating the expression of hTERT and bcl-2.