LATS1 Promotes B-ALL Tumorigenesis by Regulating YAP1 Phosphorylation and Subcellular Localization

Objective YAP1 plays a dual role as an oncogene and tumor suppressor gene in several tumors;differentiating between these roles may depend on the YAP1 phosphorylation pattern.The specific function of YAP1 in B cell acute lymphoblastic leukemia(B-ALL),however,is currently unclear.Thus,in the present study,the role of YAP1 in B-ALL was investigated using relevant cell lines and patient datasets.Methods The effects of shRNA-mediated knockdown on YAP1 and LATS1 levels in the NALM6 and MOLT-4 cell lines were examined using Western blotting,quantitative real-time polymerase chain reaction,flow cytometry,immunostaining,and nude mouse subcutaneous tumorigenesis experiments.Gene expression levels of Hippo pathway-related molecules before and after verteporfin(VP)treatment were compared using RNA-Seq to identify significant Hippo pathway-related genes in NALM6 cells.Results Patients with ALL showing high YAP1 expression and low YAP1-Ser127 phosphorylation levels had worse prognoses than those with low YAP1 protein expression and high YAP1-Ser127 phosphorylation levels.YAP1-Ser127 phosphorylation levels were lower in NALM6 cells than in MOLT-4 and control cells;YAP1 was distributed in the nuclei in NALM6 cells.Knockdown of YAP1 inhibited MOLT-4 and NALM6 cell proliferation and arrested the NALM6 cell cycle in the G0/G1 phase.Before and after VP treatment,the expression of the upstream gene LATS1 was upregulated;its overexpression promoted YAP1-Ser127 phosphorylation.Further,YAP1 was distributed in the plasma.Conclusion LATS1 may downregulate YAP1-Ser127 phosphorylation and maintain B-ALL cell function;thus,VP,which targets this axis,may serve as a new therapeutic method for improving the outcomes for B-ALL patients.

Hippo-YAP/TAZ signaling in breast cancer:Reciprocal regulation of microRNAs and implications in precision medicine

Breast cancer is a molecularly heterogeneous disease and the most common female malignancy.In recent years,therapy approaches have evolved to accommodate molecular diversity,with a focus on more biologically based therapies to minimize negative consequences.To regulate cell fate in human breast cells,the Hippo signaling pathway has been associated with the alpha subtype of estrogen receptors.This pathway regulates tissue size,regeneration,and healing,as well as the survival of tissue-specific stem cells,proliferation,and apoptosis in a variety of organs,allowing for cell differentiation.Hippo signaling is mediated by the kinases MST1,MST2,LATS1,and LATS2,as well as the adaptor proteins SAV1 and MOB.These kinases phosphorylate the downstream effectors of the Hippo pathway,yes-associated protein(YAP),and transcriptional coactivator with PDZ-binding motif(TAZ),suppressing the expression of their downstream target genes.The Hippo signaling pathway kinase cascade plays a significant role in all cancers.Understanding the principles of this kinase cascade would prevent the occurrence of breast cancer.In recent years,small noncoding RNAs,or microRNAs,have been implicated in the development of several malignancies,including breast cancer.The interconnections between miRNAs and Hippo signaling pathway core proteins in the breast,on the other hand,remain poorly understood.In this review,we focused on highlighting the Hippo signaling system,its key parts,its importance in breast cancer,and its regulation by miRNAs and other related pathways.