Depressing the immune escape of acute myelomonocytic leukemia via an anti-Fas ribozyme / 中国实验血液学杂志

ABSTRACT

In order to investigate the inhibition role of anti-Fas hammerhead ribozyme on Fas expression and Fas-mediated apoptosis in CTLL-2 cells (mouse CTL cell line), and to explore a new way for enhancing the ability of T cells against Leukemia in donor lymphocytes infusion, CTLL-2 cells were transfected with pEGFP-RZ596 and pEGFPC1 (mock-transfected) via electroporation. Fas expression on CTLL-2 cells was detected by RT-PCR and Western blot. The killing effect of CTL against WEHI-3 (mouse acute myelomonocytic leukemia cell line) highly expressing FasL in vitro was detected by MTT assay. The caspase-3 proteolytic activity and the apoptosis rate of CTLL-2 cells were detected by means of BD AproAlert Caspase-3 Colorimetric kit and FITC labeled Annexin-V apoptosis detecting kit respectively. The results showed that the anti-Fas ribozyme could be successfully introduced into mouse CTLL-2 cells; Fas expression on the surface of cells transfected with the ribozyme was obviously decreased, in comparison with control and mock-transfected cells; after cocultured with WEHI-3 cells, the viability of CTLL-2 cells transfeced with the ribozyme was significantly increased, as compared with other two groups; caspase-3 activity and apoptosis rate of the ribozyme-transfeced cells were significantly decreased, the killing effect of CTLL-2 transfected with the ribozyme was stronger than that of other groups. It is concluded that anti-Fas ribozyme can remarkably decrease Fas expression on CTLL-2 cells, so as to avoid Fas-mediated apoptosis by Fas ligand on WEHI-3 cells, and to enhance their killing activity against WEHI-3 cells, as a result, the immune escape of acute myelomonocytic leukemia was depressed.