The Effects And Mechanisms Of Baicalin On Inducing CEM Cells Apoptosis And Growth Inhibition

【Objective】To investigate the effects of baicalin on proliferation inhibition and apoptosis induction in human T lymphocyte leukemia cell line CEM cells and on related proteins and mRNA expressions, and the involvement of PI3-K/Akt signal pathway.【Methods】CEM cells were exposed to baicalin at different dosages. Proliferation inhibition was detected by both MTT assay and clone formation assay. The ability of baicalin to induce apoptosis of CEM cells was examined by Annexin- V/PI double staining analysis, acridine orange/ethidium bromide(AO/EB) double staining, and DNA fragmentation. The expressions of c-myc,bcl-2, and bax gene were detected by RT-PCR; and the protein expressions of c-myc,bcl-2,pro-caspase-3, pro-caspase-9 , PARP and Akt signal pathway molecules were detected by Western-blotting.【Results】(1)Baicalin remarkably inhibited the CEM cells proliferation, with an IC50 value of 30μM. Concomitantly, apoptosis was induced in CEM cells, as measured by detection of DNA fragmentation, staining with Annexin V and AO-EB. These showed that baicalin induced apoptosis in CEM cells in dose-dependent and time-dependent manners between certain range of concentrations of baicalin.(2)The expression of bcl-2 and c-myc mRNA decreased gradually with the prolongation of the treatment of 80μM baicalin,while the expression of bax mRNA gradually increased. The decrease of bcl-2, c-myc, pro-caspase-3 and pro-caspase-9 protein was also detected.(3)The expression of p-Akt,IκB-α,p-IκB-α,p65,p-p65,m-TOR,p-GSK-3βin Akt signal pathway and MAPK,p-MAPK in MAPK signal pathway of CEM cells were downregulated after 80μM baicalin treatment, but Akt and GSK-3βnot obviously altered.【Conclusion】(1)Baicalin could efficiently induce proliferation inhibition and apoptosis in CEM cells, in which down-regulation of bcl-2,c-myc,pro-caspase-3 and pro-caspase-9 mRNA and/or protein expressions may involve . (2)Akt signal pathway may be involved in apoptosis of CEM cells after treatment with Baicalin.