Cell Stem Cell封面文章：消灭白血病干细胞，最近《Cell Stem Cell》报道了爱荷华大学研究团队的两种已获批准的安全药物可以改善慢性白血病（CML）治疗现状及相关机理的研究文章。

SUMMARY：Effective treatment of chronic myelogenous leukemia (CML) largely depends on the eradication of CML leukemic stem cells (LSCs). We recently showed that CML LSCs depend on Tcf1 and Lef1 factors for self-renewal. Using a connectivity map, we identified prostaglandin E1 (PGE1) as a small molecule that partly elicited the gene expression changes in LSCs caused by Tcf1/Lef1 deficiency. Although it has little impact on normal hematopoiesis, we found that PGE1 treatment impaired the persistence and activity of LSCs in a pre-clinical murine CML model and axenograft model of transplanted CML patient CD34+ stem/progenitor cells. Mechanistically, PGE1 acted on the EP4 receptor and repressed Fosb and Fos AP-1factors in a b-catenin-independent manner. Misoprostol, an FDA-approved EP4 agonist, conferred similar protection against CML. These findings suggest that activation of this PGE1-EP4 pathway specifically targets CML LSCs and that the combination of PGE1/misoprostol with conventional tyrosine-kinase inhibitors could provide effective therapy for CML.（具体细节见：Prostaglandin E1 and Its Analog Misoprostol Inhibit Human CML Stem Cell Self-Renewal via EP4 Receptor Activation and Repression of AP-1）。