Influence of miR-10b on proliferation and the invasive potential of osteosarcoma

Author(s)

Gabriela Molinari Roberto

• Document type: Master's Dissertation
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina de Ribeirão Preto (PCARP/BC)
• Defense date: 2017-07-20

Examining board members

Maria Sol Brassesco Annichini; Edgard Eduard Engel; Marilia de Arruda Cardoso Smith

• Advisor: Maria Sol Brassesco Annichini

Abstract

Osteosarcoma (OS) is the most common pediatric bone tumor. The current treatment consists of surgical removal and neo- and adjuvant multimodal chemotherapy. Nonetheless, one-third of patients are affected by post-surgical recurrence and distant metastases, with only 20% of metastatic cases surviving after 5 years. Several miRNAs have been designated as metastamiRs, among them miR-10b. This microRNA is overexpressed in a series of tumors and associated with poor prognosis. Previous studies have shown that miR-10b acts on invasive processes mainly by pairing with the messenger RNA of the HOXD10 and thereby inhibiting its translation. This transcription factor, like all members of the HOX family, exerts its function by activating and/or repressing vital genes for cell growth and differentiation (even during the development of bone tissue) and is also described as deregulated in several tumors. In view of this, the aim of this work was to study the influence of miR-10b on OS and its association with the HOXD10 in relation to proliferation, invasion and cell migration. For this, the expression of both genes in tumor samples, as well as the effects of miR-10b expression modulation on the proliferative and invasive capacity of OS cell lines, were evaluated. Our results showed an inverse association between miR-10b expression levels and the degree of malignancy. The increase of miR-10b in vitro led to the suppression of clonogenic capacity and reduction of adhesion, migration and invasion, suggesting a role as a tumor suppressor in OS. No correlation was found between the gene expression of miR-10b and HOXD10, while the increase of the microRNA did not alter the protein levels of the transcription factor. Thus, the mechanism by which miR- 10b could contribute to OS aggressiveness remains undefined, though it appears to be independent of HOXD10. In parallel, the expression of KLF4 (recently described as a direct miR-10b target) and of genes known to be associated with invasion (MMP2 and ROCK1) and proliferation (TP53 and BCL2) was not affected after transfection. On the other hand, although HOXD10 was not confirmed as a miR-10b target in our study, this gene was found to be significantly overexpressed in the OS samples. Thus, considering the importance of the deregulation of developmental pathways on pediatric tumors and HOXD10 contribution on bone development, its role as an oncogene and its potential as a therapeutic target in this tumor type deserves further studies. (AU)

• FAPESP's process: 15/00524-5 - Influence of miR-10b on proliferation and the invasive potential of osteosarcoma
• Grantee: Gabriela Molinari Roberto
• Support Opportunities: Scholarships in Brazil - Master