LRP6 and breast cancer: A natural plant polyphenol rottlerin inhibited Wnt signaling in human prostate cancer PC-3 and DU145 cells and breast cancer MDA-MB-231 and T-47D cells through an interesting mechanism of reduction of phosphorylation (essential for activity) and protein levels of the Wnt coreceptor LRP6, not affecting LRP6 transcription [174].