胃癌（GC）转移的可靶向分子驱动因子尚未被广泛发现，导致晚期GC的有限靶向治疗选项。我们旨在确定转移的分子驱动因子，并制定相应的治疗策略。我们在使用基因工程的GC小鼠模型进行无偏的体内基因组范围CRISPR/Cas9敲除（KO）筛选的腹膜播散中执行。通过使用KO细胞进行体内移植实验证实了候选基因。我们使用免疫组织化学分析了GC临床样本中的目标表达模式。通过敲减，敲除和过表达方法在肿瘤球和器官球实验中研究了靶基因的功能贡献。针对Bcl-2家族成员和YAP的小分子化学抑制剂在体外和体内进行了测试。我们通过筛选确定了Nf2和Rasa1作为转移抑制基因。临床上，RASA1突变和低NF2表达定义了一个分子亚型，表现出侵袭性特征的转移性GC。NF2和RASA1的缺陷通过在肿瘤干细胞（CSCs）中共同放大Wnt和YAP信号来增加体内转移和体外肿瘤球的形成能力。NF2缺陷增强了Bcl-2介导的Wnt信号，赋予CSCs对YAP抑制的抵抗力。通过同时抑制YAP和Bcl-2实现的合成致死效应抵消了这种抵抗。RASA1缺陷通过Bcl-xL放大了Wnt途径，促进了癌干性。RASA1突变导致易感性Bcl-xL抑制，但额外的NF2缺失通过YAP激活导致对Bcl-xL抑制的抵抗。在RASA1和NF2共缺失中，Bcl-xL和YAP的联合抑制协同抑制了癌干性和体内转移。我们的研究揭示了YAP和Bcl-2家族成员之间错综复杂的相互作用，这可以导致合成致死效应，提供了克服药物抵抗的潜在策略。重要的是，我们的发现支持个体化医学的方法，即根据NF2和RASA1状态定制的靶向YAP和Bcl-2的联合治疗可以有效管理转移性GC。© 著作权归BioMed Central有限公司2023年，Springer Nature的一部分。

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.© 2023. BioMed Central Ltd., part of Springer Nature.