Role and mechanism of autophagy in the arsenic trioxide-induced death of Burkitt lymphoma Raji cells / 中国药理学通报

Aim To investigate the role of autophagy and its mechanism in Raji cell death induced by arse-nic trioxide. Methods Transmission electron micros-copy ( SEM) and MDC fluorescence staining were used to observe autophagy. MTT colorimetry was employed to assay the cellular proliferating activity. Cell apopto-sis and cell cycle analysis were performed using FITC-Annexin-V/PI double staining and flow cytometry ( FCM) . The expressions of LC3 and the conversion of LC3-I to LC3-II were measured by western bloting. The expression of bcl-2 mRNA and p53 mRNA were detected by reverse transcription-polymerase chain re-action ( RT-PCR ) . Results Arsenic trioxide could obviously inhibit the proliferation of Raji cells, arrest the cells at G2/M phase and induce apoptosis. Mean-while, arsenic trioxide markedly inhibited the expres-sion of bcl-2 mRNA and enhanced the expression of p53 mRNA in Raji cells. Arsenic trioxide also induced autophagy synchronously which paralleled with the in-duction of apoptosis in Raji cells, and 3-MA, an auto-phagy inhibitor, was able to reverse the arsenic triox-ide-activated autophagic activity, up-regulate bcl-2, down-regulated p53 expression and suppress the lethal effect of arsenic trioxide on Raji cells to reduce their sensitivity to arsenic trioxide. In contrast, the Rapamy-cin, an autophagy inducer, possessed the completely opposite effects on Raji cells compared with 3-MA. Conclusions The apoptosis and autophagic cell death are coexistent in arsenic trioxide-triggered death of Raji lymphoma cells, and Bcl-2 and p53 may play a key regulating role in this process.

The apoptosis-inducing effect of MnSOD_m on K562 cells and its molecular mechanism / 中国药理学通报

Aim To explore the apoptotic effect of mimics of manganese superoxide dismutase(MnSODm)on human leukemia cell line K562 in vitro and the possible molecular mechanisms.Methods Human leukemia K562 cells were used as the target cells.The cell proliferating activity was examined by a MTT colorimetric assay,and the apoptosis of K562 cells was assessed with FITC-Annexin V and propidium iodide(PI)double staining and morphological changes.The expressions of bcl-2 and bax mRNA were detected by reverse transcription polymerase chain reaction(RT-PCR),and flow cytometry(FCM)was employed to measure the expressions of Bcl-2 and Bax protein,mitochondrial inner membrane potential(??m),Cytochrome C(Cyt C)release and Caspase-3 activity.Results The proliferation of K562 cells was obviously inhibited by 0.5~10 mg?L-1 MnSODm(P