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| Author(s): |
Candy Christie Bellido More
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Ribeirão Preto. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Medicina de Ribeirão Preto (PCARP/BC) |
| Defense date: | 2022-08-29 |
| Examining board members: |
Sonir Roberto Rauber Antonini;
Daniel Alves Bulzico;
Fabio Luiz Fernandes Rósa;
Elvis Terci Valera
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| Advisor: | Sonir Roberto Rauber Antonini; Ana Carolina Bueno de Queiroz Arruda |
| Abstract | |
Background: Adrenocortical tumors (ACT) are rare and aggressive. YAP1, a HIPPO pathway effector, is overexpressed in other types of tumors. Recently, it was shown that YAP1 overexpression is associated with worse prognosis in pediatric patients with ACT. Objectives: To evaluate the role of the YAP1 oncogene and the antitumor effect of its inhibitor, verteporfin, in adrenocortical tumorigenesis. Methods: Ex vivo and in silico, the YAP1 expression in ACT was analyzed from publicly available data from TCGA and GEO databases and the RNA-seq data of pediatric patients\' samples from FMRP/USP-Boldrini cohort. In addition, YAP1 methylation profile was analyzed from a methylation array from pediatric patients\' samples from FMRP/USP-Boldrini cohort and public data from GEO. In vitro, the role of YAP1 on ACT progression was examined using cell viability, cell cycle, soft-agar colony formation, and cell invasion assays. YAP1\'s influence on beta-catenin protein levels and transcription activity was examined by immunoblotting, immunofluorescence and real time-qPCR. In vivo, the effect of the pharmacological inhibition of YAP1 by verteporfin on tumor growth was evaluated in a mouse xenograft model of ACT. Results: We confirmed the association between YAP1 mRNA overexpression with impaired survival of pediatric patients from GEO and FMRP/USP-Boldrini cohort and adult patients from TCGA. Moreover, we identified two YAP1 methylation signatures in both pediatric cohorts evaluated. These methylation signatures were also associated with the survival of pediatric patients from the FMRP/USP-Boldrini cohort. Together, these results support the prognostic marker value of YAP1 in ACTs. In vitro, the inhibition of YAP1 reduced adrenocortical cell viability through cell cycle arrestment in G0-G1 phase, inhibited the epithelial mesenchymal transition process markers\' expression, as well as anchorage-independent growth and cell invasion. In addition, YAP1 was shown to modulate beta-catenin protein levels and transcription activity and, at the same time, beta-catenin was shown to partially mediate the effect of YAP1 on adrenocortical cells. Finally, in vivo, verteporfin inhibited the tumor growth by inhibiting tumor cell proliferation, as shown by reduced Ki67 immunoreactivity in the xenografts from treated mice. Conclusions: Our findings reinforce the role of YAP1 as a novel prognostic marker for patients with ACT, as well as demonstrate the mechanisms by which YAP1 deregulation contributes to adrenocortical tumorigenesis. This study also evidences the importance of the crosstalk between Hippo/YAP1 and Wnt/beta-catenin pathways in adrenocortical cells, which acknowledges YAP1 as a new target for the treatment of patients with ACT. (AU) | |
| FAPESP's process: | 17/17737-7 - Role of YAP1 oncogene in tumorigenesis and metastasis processes, and its inhibition in pediatric adrenocortical tumors by verteporfin |
| Grantee: | Candy Christie Bellido More |
| Support Opportunities: | Scholarships in Brazil - Doctorate (Direct) |