Deregulation of the Hippo pathway promotestumor cell proliferation through YAP activity in human sporadic vestibular schwannoma

ABSTRACT: Object: The main limitation of treatment strategies for vestibular schwannomas (VSs) is loss of function of vestibulocochlear and facial nerves, which has driven investigations into new pharmaceutical therapies. The most common genetic alteration in human VSs is loss ofthe NF2 gene which encodes the protein merlin. It is well established that merlin achieves tumor suppressive functions through regulation of the Hippo pathway. The aim of this study was to analyze dysregulation of the Hippo pathway in sporadic VSs and to identify whether Hippo signaling could be potential targetable pathway for treatment of VS. Methods: In this study, we performed gene expression profiling of ten human sporadic VSs and four normal control vestibular nerves to identify aberrant expression of the Hippo pathway in VSs. Molecular subtypes in VSs was evaluated using unsupervised hierarchical clustering analysis. Western blot analysis and immunohistochemical staining were used to examine the expression of Hippo pathway core components in twenty human sporadic VSs. NF2 gene sequencing and mutation analysis were performed in all VS samples. Ki67 marker was used to investigate proliferation of tumor cells. Verteporfin was used to determine whether the inhibitor of YAP-TEAD reduced proliferation of human primary VS cells with NF2 mutations and RT4-D6P2T cell line. Results: We found fifty-one differentially expressed genes between VSs and controls. Unsupervised analysis of transcriptional profiles identified the two distinct molecular variants, which was significantly associated with NF2 mutation status. The protein level of MST2, LAST2,phospho-LAST1, and phospho-YAP were significantly decreased in VSs compared with normal tissues. Nuclear YAP staining was positively correlated with Ki-67 indexin VS samples. Finally, verteporfin reduced viability of human primary VS cells and in a dose-dependent manner by decreasing YAP expression. Conclusions: Our findings implicate that deregulation of the Hippo pathway as a molecular mechanism of pathogenesis in human sporadic VSs, and suggest inhibition of this pathway as a potential treatment strategy.

ORGANISM(S): Homo sapiens

PROVIDER: GSE108237 | GEO | 2020/12/01

REPOSITORIES: GEO