Expression data from conditional Klf5 knockout Pten-null mouse prostates

KLF5 is a basic transcription factor that regulates multiple biological processes, but its function in tumorigenesis appears contradictory in the current literature, with some studies showing tumor suppressor activity and others showing tumor promoting activity. In this study, we examined the function of Klf5 in prostatic tumorigenesis using mice with prostate specific deletion of Klf5 and Pten, both of which are frequently deleted in human prostate cancer. Histological and molecular analyses demonstrated that when one Pten allele was deleted, which causes mouse intraepithelial neoplasia (mPIN), Klf5 deletion accelerated the emergence and progression of mPIN. When both Pten alleles were deleted, which causes prostate cancer, Klf5 deletion promoted tumor growth and caused more severe morphological and molecular alterations, and homozygous deletion of Klf5 was more effective than hemizygous deletion. Unexpectedly, while Klf5 deletion clearly promoted tumorigenesis in luminal cells, it actually diminished the numbers of Ck5-positive basal cells in the Pten-null tumors. Klf5 deletion also increased the cell proliferation rate in tumors with Pten deletion, which involved extensive activation of the PI3K/AKT and MAPK mitogenic signaling pathways and inactivation of the p15 cell cycle inhibitor. Global gene expression and pathway analyses demonstrated that multiple mechanisms could be responsible for the tumor promoting effect of Klf5 deletion,

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Xing C, Ci X, Sun X, Fu X, Zhang Z, Dong EN, Hao ZZ, Dong JT