Abstract 2520: miRNAs with potential application for diagnosis, prognosis and treatment response prediction in uterine smooth muscle tumors
Authors: de Almeida Bruna C. , Faria Isabela S. , Anjos Laura G. Dos , Maffazioli Giovana N. , Baracat Edmund C. , Carvalho Katia C. 
Published: September 2020

Background: miRNAs act as regulatory molecules at the post-transcriptional level. Their expression can influence in carcinogenesis, leading to alterations in the genetic and the epigenetic processes that contribute to tumors heterogeneous behaviors. miRNAs represent new potential biomarkers and promising translational targets in neoplasms therapy. These molecules expression has a crucial role in smooth muscle differentiation from mesenchymal stem cells. Leiomyoma (LM) is the most frequent benign uterine smooth muscle tumors (USMT), occurring in up to 80% of reproductive-age women. Leiomyosarcoma (LMS) is a malignant USMT that represents 40-60% of all gynecological sarcomas. This study aims to evaluate the expression profile and the role of miR-34a and miR-181b in LM and LMS cells.

Methods: LM (THESCs CRL-4003) and LMS (SK-UT-1) cell lines were grown in specific mediums and conditions (ATCC recommendations). Cell lines were transfected with synthetic miRNA mimics and inhibitors of miR-34a and miR-181b and evaluated for proliferation, migration and gene expression (qPCR) assays. For gene expression analysis in patients' samples, 10 myometrium (MM), 10 LM and 15 LMS were selected and compared to cell lines expression profile. In silico analysis was performed to identify miR-34a and 181b main genetic interactions network of (MirtarBase database).

Results: LM cells depicted higher basal expression levels of miR-34a and miR-181b, while the LMS presented a lower expression, both compared to MM. The same profile was observed for patients' samples. The 34a mimic showed great efficiency in expression induction at 24 h, in LM and LMS cells. Its inhibitor showed better efficacy at 72h in LM and 24 - 48h in LMS. For 181b, higher mimics efficiency was obtained at 72 and 96h in LM, and 24 and 48h in LMS. Its higher inhibition was observed at 24h, both for LM and LMS. LM cell proliferation showed a significant reduction for both mimics miRNAs at 72 and 96h, while inhibitory miRNAs decreased its proliferative capacity at 48 and 72h for 34a and only at 48h for 181b. Proliferation of LMS cells was lower only for 34a mimics at 72 and 96h and trended lower at 120h. Cell proliferation was lower when 181b was inhibited, at 72 and 96h, but a tendency was also observed at 48 and 120h. These preliminary results demonstrate a decreasing migratory rate in LM and LMS cells for 34a mimic and 181b inhibitor. In silico analysis depicted a strong interaction of the 34a, TP53 and BCL2 genes, and of the 181b, BCL2 and TIMP3. In conclusion, the upregulation of miR-34a and miR-181b induced cell proliferation and migration decrease in LM. For LMS cells, 34a upregulation was associated with the inhibition of cell proliferation and migration, while its downregulation induces the reduction of only the cell proliferation. miR-181b inhibition had an inductor effect over the LMS cells proliferation, but diminished in the cell migration.

Citation Format: Bruna C. de Almeida, Isabela S. Faria, Laura G. Dos Anjos, Giovana N. Maffazioli, Edmund C. Baracat, Katia C. Carvalho. miRNAs with potential application for diagnosis, prognosis and treatment response prediction in uterine smooth muscle tumors [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2520.