Jian feng Zhu, Zi jian Li, Guang sen Zhang, Kun Meng, Wen yong Kuang, Jin Li, Xin fu Zhou, Rui juan Li, Hong ling Peng, Chong wen Dai, Jian Kai Shen, Fan jie Gong, Yun xiao Xu, and Su fang Liu
Purpose: To explore the effects of Icaritin on chronic myeloid leukemia (CML) cells and underlying mechanisms. Method: CML cells were incubated with various concentration of Icaritin for 48 hours, the cell proliferation was analyzed by MTT and the apoptosis was assessed with Annexin V and Hoechst 33258 staining. Cell hemoglobinization was determined. Western blotting was used to evaluate the expressions of MAPK/ERK/JNK signal pathway and Jak-2/Phorpho-Stat3/Phorsph- Akt network-related protein. NOD-SCID nude mice were applied to demonstrate the anti-leukemia effect of Icaritin in vivo. Results: Icaritin potently inhibited proliferation of K562 cells (IC50 was 8 &mgr;M) and primary CML cells (IC50 was 13.4 &mgr;M for CML-CP and 18 &mgr;M for CML-BC), induced CML cells apoptosis and promoted the erythroid differentiation of K562 cells with time-dependent manner. Furthermore, Icaritin was able to suppress the growth of primary CD34+ leukemia cells (CML) and Imatinib-resistant cells, and to induce apoptosis. In mouse leukemia model, Icaritin could prolong lifespan of NOD-SCID nude mice inoculated with K562 cells as effective as Imatinib without suppression of bone marrow. Icaritin could upregulate phospho-JNK or phospho-C-Jun and down-regulate phospho-ERK, phospho-P-38, Jak-2, phospho-Stat3 and phospho-Akt expression with dose- or time-dependent manner. Icaritin had no influence both on c-Abl and phospho-c-Abl protein expression and mRNA levels of Bcr/Abl. [ABSTRACT FROM AUTHOR]