Abstract 1105: Dual tumor suppressors miR-139-5p/-3p derived from pre-miR-139 via targeting matrix metalloprotease 11 (MMP11) in bladder cancer
Authors: Yonemori Masaya , Seki Naohiko , Matsusihta Ryosuke , Miyamoto Kazutaka , Yoshino Hirofumi , Goto Yusuke , Kato Mayuko , Kurozumi Akira , Nakagawa Msayuki , Enokida Hideki 
Published: July 2016

Introduction & Objective: The molecular mechanisms of recurrence and muscle invasion process of bladder cancer (BC) are not well understood. Therefore, understanding the molecular mechanisms of metastatic pathways underlying advanced BC using currently available genomic approaches might improve therapies for and prevention of the disease. Our recent study of microRNA (miRNA) expression signature of BC by deep-sequencing revealed that miR-139-5p (guide strand) and miR-139-3p (passenger strand) were significantly downregulated in BC tissues. In miRNA biogenesis, the passenger strand of miRNA duplex is discarded, while the guide strand is retained to direct recruitment of the RISC to target mRNAs. We hypothesis that these miRNAs act as tumor suppressors in BC. The aim of the present study was to investigate the functional roles of these miRNAs and their modulation of cancer networks in BC cells.

Material & Methods: Expression levels of miR-139-5p/-3p and its candidate target genes were validated in two BC cell lines (T24 and BOY) and BC clinical specimens (62 BCs and 23 normal bladder epitheliums: NBEs) by real-time PCR methods. Gain-of-function study, cell proliferation, migration, and invasion analyses were performed by using miR-139-5p/-3p transfected BC cell lines. In silico database and genome-wide gene expression analyses were applied for identification of miR-139-5p/-3p targets. Loss-of-function study for its target gene was performed by using siRNAs. Luciferase reporter analyses were employed to validate direct binding between the target gene and miR-139-5p/-3p. Overall patient survival between high and low expression of the target gene was analyzed by the Kaplan-Meier method.

Results: The expression levels of miR-139-5p and miR-139-3p were significantly reduced in tumor tissues and BC cell lines compared with NBEs (P&lt; 0.0001). Restoration of miR-139-5p or miR-139-3p in cancer cells revealed that both miRNAs inhibited cancer cell migration and invasion. Our data demonstrated that the gene coding for matrix metalloprotease 11 (MMP11) was a direct target of miR-139-5p/-3p regulation. Silencing of MMP11 inhibited cell migration and invasion in BC cells. Moreover, Kaplan-Meier analysis revealed that the patients with high MMP11 expression had lower overall survival probabilities than those with low expression (P = 0.043).

Conclusions: Aberrant expressed novel miRNAs were identified by deep sequencing of BC miRNA signature. Two mature miRNAs, miR-139-5p and miR-139-3p derived from pre-miR-139 act as tumor-suppressors in BC cells. To the best of our knowledge, this is the first report demonstrating that dual tumor-suppressive miR-139-5p/-3p directly regulate MMP11 in BC cells. The identification of novel target gene regulated by the dual tumor-suppressors may lead to a better understanding of BC and the development of new therapeutic strategies to treat this disease.

Citation Format: Masaya Yonemori, Naohiko Seki, Ryosuke Matsusihta, Kazutaka Miyamoto, Hirofumi Yoshino, Yusuke Goto, Mayuko Kato, Akira Kurozumi, Msayuki Nakagawa, Hideki Enokida. Dual tumor suppressors miR-139-5p/-3p derived from pre-miR-139 via targeting matrix metalloprotease 11 (MMP11) in bladder cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1105.