Jong‑Wan Kwon1†, Jeong‑Seop Oh2,3†, Sang Hyeok Seok1, Hyeok‑Won An1, Yu Jin Lee1, Na Yun Lee1, Taehun Ha1, Hyeon Ah Kim1, Gyeong Min Yoon1, Sung Eun Kim1, Pu‑Reum Oh1, Su‑Hyung Lee4, Dominic C. Voon5,6, Dae‑Yong Kim2,3* and Jun Won Park1*
1Division of Biomedical Convergence, College of Biomedical Science, Kangwon National University, 1, Kangwondaehak‑Gil, Chuncheon‑Si, Gangwon‑Do 24341, Republic of Korea.
2Department of Veterinary Pathology, College of Veterinary Medicine, Seoul National University, 1, Gwanak‑Ro, Gwanak‑Gu, Seoul 08826, Republic of Korea.
3Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul 08826, Republic of Korea.
4Section of Surgical Sciences, Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, TN, USA.
5Cancer Research Institute, Kanazawa University, Kanazawa, Ishikawa 920‑1192, Japan.
6Innovative Cancer Model Research Unit, Institute for Frontier Science Initiative, Kanazawa University, Kanazawa, Ishikawa 920‑1192, Japan.
†Jong-Wan Kwon and Jeong-Seop Oh equally contributed to this work.
*Correspondence: Dae‑Yong Kim, Jun Won Park
Targetable molecular drivers of gastric cancer (GC) metastasis remain largely unidentified, leading to limited targeted therapy options for advanced GC. We aimed to identify molecular drivers for metastasis and devise corresponding therapeutic strategies.
We performed an unbiased in vivo genome-wide CRISPR/Cas9 knockout (KO) screening in peritoneal dissemination using genetically engineered GC mouse models. Candidate genes were validated through in vivo transplantation assays using KO cells. We analyzed target expression patterns in GC clinical samples using immunohistochemistry. The functional contributions of target genes were studied through knockdown, KO, and overexpression approaches in tumorsphere and organoid assays. Small chemical inhibitors against Bcl-2 members and YAP were tested in vitro and in vivo.
We identified Nf2 and Rasa1 as metastasis-suppressing genes through the screening. Clinically, RASA1 mutations along with low NF2 expression define a distinct molecular subtype of metastatic GC exhibiting aggressive traits. NF2 and RASA1 deficiency increased in vivo metastasis and in vitro tumorsphere formation by synergistically amplifying Wnt and YAP signaling in cancer stem cells (CSCs). NF2 deficiency enhanced Bcl-2-mediated Wnt signaling, conferring resistance to YAP inhibition in CSCs. This resistance was counteracted via synthetic lethality achieved by simultaneous inhibition of YAP and Bcl-2. RASA1 deficiency amplified the Wnt pathway via Bcl-xL, contributing to cancer stemness. RASA1 mutation created vulnerability to Bcl-xL inhibition, but the additional NF2 deletion conferred resistance to Bcl-xL inhibition due to YAP activation. The combined inhibition of Bcl-xL and YAP synergistically suppressed cancer stemness and in vivo metastasis in RASA1 and NF2 co-deficiency.
Our research unveils the intricate interplay between YAP and Bcl-2 family members, which can lead to synthetic lethality, offering a potential strategy to overcome drug resistance. Importantly, our findings support a personalized medicine approach where combined therapy targeting YAP and Bcl-2, tailored to NF2 and RASA1 status, could effectively manage metastatic GC.