Program

Poster Presentations

Day 1, June 10（Wed.）　　Room P (5F 501+502)

1P-26

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Identification of Mutant RhoA–Interacting Proteins in Diffuse-type gastric cancer

(¹Univ. Tokyo, ²Univ. Tokyo, ³Yokohama Pharm. Univ.)
^oHiroto Ogihara^1,2, Yoko Chikaoka², Kazuki Yamamoto², Aya Nakayama², Hiroyuki Aburatani¹, Toshiya Tanaka¹, Toru Kozasa³, Takeshi Kawamura^1,2

Diffuse-type gastric cancer (DGC), also known as scirrhous gastric cancer, is a highly aggressive malignancy characterized by rapid progression, poor prognosis, and the lack of effective standard therapies. Recent genomic studies have revealed that mutations in the RHOA gene are specifically enriched in DGC and form mutational hotspots. Cancer cells harboring mutant RHOA have been reported to depend on mutant RHOA for proliferation, suggesting that mutant RHOA may represent a potential therapeutic target. However, proteins that specifically interact with mutant RhoA remain poorly understood. In this study, we comprehensively analyzed mutant RhoA–associated proteins in three cancer cell lines (HeLa, MKN74, and NUGC4) using DIA-based proteomics on an Orbitrap Fusion mass spectrometer following V5-tag immunoprecipitation. Several proteins showing fold change ≥3 relative to wild-type were identified for hotspot mutants RhoA G17E and Y42C in a cell line–dependent manner. These results suggest that mutant RhoA interacts with distinct proteins depending on cellular context and may contribute to malignant phenotypes in DGC.

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