Antitumor activity of total paeony glycoside against human chronic myelocytic leukemia K562 cell lines in vitro and in vivo.

To explore the molecular mechanisms of human leukemia cells by total paeony glycoside (TPG), which is extracted from the root of Radix Paeoniae Rubra. The viability of K562 cells was assessed by MTT assay. Flow cytometry was used to detect apoptosis and cell cycle analysis. The changes in intracellular Ca(2+) concentration were determined by fluorescent dye Fluo-3, and mitochondrial membrane potential was determined by the retention of the dye Rh123. The cytoplasmic Bax, Bcl-xL, and Bcl-2 protein expressions were determined by western blot. The mRNA expression of caspase-3, caspase-8, and caspase-9 was detected by RT-PCR. K562 cells were subcutaneously inoculated into nude mice to study the in vivo antitumor effects of TPG. The growth of K562 cells was inhibited and arrested in G0/G1 phase by TPG. TPG also caused apoptosis in K562 cells evidenced by cytosolic accumulation of cytochrome c, caspase-9, and caspase-3. TPG could down-regulate Bcl-2 and Bcl-xL and up-regulate Bax in K562 cells. TPG showed a significant decreased tumor volume and tumor weight in nude mice inoculated with K562 cells. TPG can be developed as a promising anti-chronic myeloid leukemia drug.