Abstract LB274: Nuclear transporter HIKESHI is a novel independent poor overall survival for pancreatic cancer; targeting can inhibit pancreatic cancer growth via HSP70 suppression
Authors: Erkhem-Ochir Bilguun , Yokobori Takehiko , Dorjkhorloo Gendensuren , Okami Haruka , Seki Takaomi , Harimoto Norifumi , Muranushi Ryo , Hoshino Kouki , Hagiwara Kei , Ishii Norihiro , Tsukagoshi Mariko , Araki Kenichiro , Saeki Hiroshi , Shirabe Ken 
Published: April 2024

Abstract
HIKESHI, under heat stress conditions, has been reported to transport molecular chaperone HSP70 into the nucleus to prevent cancer cell death from heat stress. The tumor-supporting roles of molecular chaperones in various solid tumors are explored extensively. Yet, the sole targeting of the molecular chaperones could not significantly impact anticancer treatment. Thus, we hypothesized that the specific transporter protein HIKESHI might improve this outcome. However, understanding of the clinical relevance of HIKESHI in pancreatic cancer remained unclear, and few studies addressed the HIKESHI role in cancer and whether targeting can inhibit pancreatic cancer cell viability and the other HSPs. Here, we first investigated the expression pattern of the HIKESHI protein in surgically resected pancreatic cancer samples (n=142) and analyzed the clinical relevance of the HIKESHI. We found that the HIKESHI protein was overexpressed in cancer compared to the adjacent normal tissue, and positive expression of cancer HIKESHI was related to poor overall survival. In addition, HIKESHI-positive expression in cancer was identified as an independent prognostic marker for overall survival. Next, using shRNA, we established the stable HIKESHI-suppressed pancreatic cancer cell line (PANC-1). HIKESHI suppression inhibited cell growth and colony formation ability in vitro. The expression and nuclear translocation of HSP70 and HSP110/105 were suppressed in HIKESHI-suppressed cells compared to the control shRNA cells despite no heat stress conditions. Furthermore, we found that the tumor growth, HIKESHI, and Ki67 expression in HIKESHI-suppressed tumors were inhibited compared to the control shRNA tumors. Next, we performed Cap Analysis of Gene Expression and IP-MS analysis to discover the potential downstream and novel interactive partner of the HIKESHI protein. The extensive mechanism of these analyses is under investigation. Our findings suggest that targeting HIKESHI may be a promising therapeutic strategy against refractory pancreatic cancer.
Citation Format: Bilguun Erkhem-Ochir, Takehiko Yokobori, Gendensuren Dorjkhorloo, Haruka Okami, Takaomi Seki, Norifumi Harimoto, Ryo Muranushi, Kouki Hoshino, Kei Hagiwara, Norihiro Ishii, Mariko Tsukagoshi, Kenichiro Araki, Hiroshi Saeki, Ken Shirabe. Nuclear transporter HIKESHI is a novel independent poor overall survival for pancreatic cancer; targeting can inhibit pancreatic cancer growth via HSP70 suppression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB274.