Establishment of new cancer treatment targeting Intracellular molecules via extracellular vesicles

2020 Fiscal Year Final Research Report

• Project/Area Number: 19K16821
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 50020:Tumor diagnostics and therapeutics-related
• Research Institution: 株式会社関西メディカルネット(関西電力医学研究所)
• Principal Investigator: INANO SHOJIRO 株式会社関西メディカルネット(関西電力医学研究所), 臨床腫瘍研究部, 上級特別研究員 (70811199)
• Project Period (FY): 2019-04-01 – 2021-03-31
• Keywords: エクソソーム / ユビキチン化 / 膵癌 / KRAS

Outline of Final Research Achievements

We screened and generated a chimeric protein composed of "extracellular vesicle transition sequence"-"substrate recognition subunit of CRL complex"-"anti-GFP nanobody", which efficiently degraded GFP via ubiquitilation. Next, we focused on KRAS protein that plays central role in pancreatic cancer. By replacing GFP nanobody with KRAS binding motif, we achieved GTP-bound type specifi KRAS degradation in several cell lines including 293T, HeLa, or U2OS, as well as five pancreatic cancer cell lines. Finally, we isolated extracellular vesicles from culture supernatant of 293T cells expressing this protein, .and treated pancreatic cancer cell line. Treated cells exhibited decreased KRAS expression and impaired proliferation, confirming the direct thrasher of functional protein via extracellular vesicles.

Free Research Field

血液内科、腫瘍内科

Academic Significance and Societal Importance of the Research Achievements

がん治療は日々進歩を続けているものの、細胞内の分子を標的とする手段はまだまだ少なく、特にKRASは長年がん治療の標的として有望視されてきたものの、いまだに制御する手段が乏しいと言わざるを得ません。本研究ではエクソソソームを解して直接的に活性化型KRASの分解を促す蛋白を細胞に移行させることでKRASの活性化型特異的分解を達成しました。この方法をウイルスによる遺伝子治療、あるいは細胞治療と組み合わせることで、新しいがん治療樹立の可能性が見えてきます。