Study On The Antitumor Effect Of Longdaysin By Blocking Wnt/?-catenin Signaling In Breast Cancer Cells

The Wnt/?-catenin signaling pathway plays a pivotal role in embryonic development,tumorigenesis and stem cell self-renew.Casein kinase 1(CK1)is involved in regulating Wnt/?-catenin signaling,and represents a promising target for the treatment of breast cancer.A purine derivative longdaysin has recently been identified as a novel modulator of cellular circadian rhythms through targeting the protein kinases CK1?,CK1? and ERK2.However,the antitumor activity of longdaysin and its underlying mechanisms remain unclear.The inhibitory effect of longdaysin on Wnt/?-catenin signaling was investigated using the SuperTOPFlash reporter system.In breast cancer Hs578 T and MDA-MB-231 cells,Wntrelated protein were examined by Western Blot.The expression of Wnt target genes were determined using Real-time PCR.The effects of longdaysin on cancer cell colony formation was measured by colony formation assay.The effects of longdaysin on cancer cell migration and invasion were assessed using transwell assays.The effect of longdaysin on Hs578 T cancer stem cell was tested by sphere formation assay.The in vivo antitumor effect of longdaysin was performed using MDA-MB-231 breast cancer xenografts.Our results demonstrated that longdaysin could inhibit the Wnt/?-catenin pathway by targeting CK1?/?.This compound markedly decreased phosphorylation of LRP6 and DVL2,and reduced the levels of active ?-catenin and total ?-catenin protein,finally leading to the transcriptional downregulation of Wnt target genes.We further demonstrated that longdaysin could repress breast cancer cell colony formation,migration and invasion in a CK1?/?-dependent manner.In breast cancer xenografts,longdaysin suppressed in vivo tumor growth with concurrent inhibition of Wnt/?-catenin signaling.Taken together,this study for the first time demonstrated that longdaysin elicits its antibreast cancer activity through targeting the Wnt/?-catenin signaling pathway.Our results indicate that longdaysin may be a promising agent for breast cancer treatment.