Analysis of WASF3 gene and protein expression in thyroid cancer.

Author(s)

Lourenço Proença Ruivo

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Ciências Biomédicas (ICB/SDI)
• Defense date: 2024-05-06

Examining board members

Edna Teruko Kimura; Rosalinda Yossie Asato de Camargo; Nathalie Cella; Joao Roberto Maciel Martins

• Advisor: Edna Teruko Kimura

Abstract

Thyroid cancer is the most prevalent malignancy of the endocrine system. Among the histotypes, papillary thyroid carcinoma (PTC) is the most common, with a high prevalence of mutation in the BRAF gene, a member of the MAPK pathway. Despite its good prognosis, PTC can become aggressive and refractory to conventional treatments, highlighting the importance of understanding other alterations that affect this carcinoma. The WASF3 protein is involved in changes in cell morphology and cytoskeletal organization, and its increased expression is related to greater migration and invasion in different types of cancer. In this study, we evaluated the gene and protein expression of WASF3 in papillary thyroid cancer. The expression of the WASF3 protein was analyzed by immunohistochemistry (IHC) in the thyroids of transgenic BRAFT1799A (BRAF+) mice and wild-type (WT) mice of different ages (5 to 60 weeks), and by IHC and immunofluorescence (IF) in human tumor and non-tumor tissues. Using PTC cell lines (TPC-1, BCPAP, and K1), WASF3 gene and protein expression were assessed by RT-qPCR and Western Blotting. In silico mRNA expression was accessed using the UCSC Xena Browser platform with information obtained from The Cancer Genome Atlas (TCGA) and The Genotype-Tissue Expression (GTEx) project databases. In our results, we observed that BRAF+ mouse tissue showed higher expression of WASF3 compared to WT animals, with immunopositivity occurring in the cytoplasm of follicular cells, and an increase in expression with age. As WASF3 expression increased in BRAF+ PTC, a granular pattern of positivity was observed in the cytoplasm and a preference for accumulation in the apical or basal region of the thyrocytes. In human tissues, higher expression of WASF3 was observed in PTC. The staining occurred throughout the cell cytoplasm, showing stronger expression in the membrane region in some cells. On the other hand, PTC cell lines showed a reduction in gene and protein expression when compared to non-tumoral cell lines. Additionally, in silico research in large-scale databases revealed a 16% decrease in WASF3 expression in human PTC. The difference between the protein expression of WASF3 in IHC in tumor tissue and gene expression in in vitro and in silico studies needs to be elucidated. The high expression of the WASF3 protein in the animal model of PTC and in human PTC suggests its participation in thyroid carcinogenesis. (AU)

• FAPESP's process: 21/11669-5 - Analysis of WASF3 expression in thyroid cancer
• Grantee: Lourenço Proença Ruivo
• Support Opportunities: Scholarships in Brazil - Master