News Releases & Research Results Elucidation of a novel mechanism of exosome secretion in prostate cancer cells: Opening the way to novel prostate cancer therapies targeting exosomes

The results of collaborative research and development (R&D) conducted by Professor Takahiro Ochiya of the Institute of Medical Science, Tokyo Medical University; Professor Shin Egawa and Assistant Professor Fumihiko Urabe of the Department of Urology, Jikei University School of Medicine; and Theoria Science, Inc. (Representative Director: Takayuki Mizutani).

• The research group successfully elucidated the mechanism of exosome (*) ecretion in prostate cancer (PCa) cells using an originally developed screening method.
  * Lipid bilayer-enclosed vesicles measuring about 100 nm in size and secreted by various kinds of cells. They play important roles in intercellular communication.
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• Specifically, screening of PCa cell lines showed that miR-26a, a type of microRNA, and its target genes regulated exosome secretion.
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• The transplantation of PCa with down-regulated expression of these genes into mice resulted in reduction of exosome secretion and suppression of tumor growth in those mice. In addition, tumor growth was recovered upon simultaneous injection of exosomes from PCa cells at the site of transplantation of the PCa cells with reduced exosome secretion.
• The results of R&D should lead to the development of new cancer therapies targeting exosomes.

This R&D project was conducted with the support of Practical Research for Innovative Cancer Control and Project for Cancer Research and Therapeutic Evolution (P-CREATE) by AMED.

The results of R&D were published in Science Advances, an American scientific journal, on April 30.

Urabe F., et al. miR-26a regulates extracellular vesicle secretion from prostate cancer cells via targeting SHC4, PFDN4, and CHORDC1 Science Advances
DOI：10.1126/sciadv.aay3051