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Gastric carcinomas (GC) are heterogeneous tumors, composed of a subpopulation of cluster of differentiation‐44 (CD44)+ tumorigenic and chemoresistant cancer stem cells (CSC). YAP1 and TAZ oncoproteins (Y/T) interact with TEA domain family member 1 (TEAD) transcription factors to promote cell survival and proliferation in multiple tissues. Their activity and role in GC remain unclear. This work aimed to analyze Y/T‐TEAD activity and molecular signature in gastric CSC, and to assess the effect of verteporfin, a Food and Drug Administration‐approved drug preventing Y/T‐TEAD interaction, on gastric CSC tumorigenic properties. Y/T‐TEAD molecular signature was investigated using bioinformatical (KmPlot database), transcriptomic and immunostaining analyses in patient‐derived GC and cell lines. Verteporfin effects on Y/T‐TEAD transcriptional activity, CSC proliferation and tumorigenic properties were evaluated using in vitro tumorsphere assays and mouse models of patient‐derived GC xenografts. High expressions of YAP1, TAZ, TEAD1, TEAD4 and their target genes were associated with low overall survival in nonmetastatic human GC patients (n = 444). This Y/T‐TEAD molecular signature was enriched in CD44+ patient‐derived GC cells and in cells resistant to conventional chemotherapy. Verteporfin treatment inhibited Y/T‐TEAD transcriptional activity, cell proliferation and CD44 expression, and decreased the pool of tumorsphere‐forming CD44+/aldehyde dehydrogenase (ALDH)high gastric CSC. Finally, verteporfin treatment inhibited GC tumor growth in vivo; the residual tumor cells exhibited reduced expressions of CD44 and ALDH1, and more importantly, they were unable to initiate new tumorspheres in vitro. All these data demonstrate that Y/T‐TEAD activity controls gastric CSC tumorigenic properties. The repositioning of verteporfin targeting YAP1/TAZ‐TEAD activity could be a promising CSC‐based strategy for the treatment of GC. What's new? In gastric cancer, populations of cancer stem cells (CSCs), which initiate and sustain tumor growth and drive tumor recurrence, are maintained through activity of the yes‐associated protein 1 (YAP1), TAZ, and TEA domain transcription factor (TEAD) complex. In this study, employing gastric cancer models, transcriptional activity of the YAP1/TAZ‐TEAD complex was successfully inhibited by the benzoporphyrin derivative verteporfin. Specifically, verteporfin decreased the pool of gastric CSCs in vitro and in vivo and inhibited tumor growth in patient‐derived gastric cancer xenografts. The results suggest that targeting YAP1/TAZ‐TEAD activity with verteporfin is a promising therapeutic strategy for gastric cancer. [ABSTRACT FROM AUTHOR]

Uveal melanoma (UM) can remain in clinical dormancy for decades only to later produce lethal metastases. Using Gαq/11 mut /BAP1 wt UM xenograft models and human metastatic samples, we identified NR2F1 as a key inducer of UM disseminated cancer cell (DCC) dormancy. Dormant UM DCCs upregulate NR2F1, neural crest genes and, along with suppression of proliferation programs, NR2F1 silences YAP1/TEAD1 transcription by altering histone H3 activation marks. YAP1 can reciprocally repress NR2F1, but inhibiting Gαq/11 signaling or activating NR2F1 can arrest UM growth. NR2F1 knockout led to dormant DCC awakening and liver metastatic growth. NR2F1 and YAP1 inverse expression was confirmed in human livers carrying UM solitary, small DCC clusters as well as large metastases. Intriguingly, RNA-seq and Cut&Run analysis revealed that NR2F1 short-circuits oncogene signaling by repressing multiple G-protein signaling components. Our work provides previously unrecognized mechanistic insight into UM DCC dormancy and potential pathways for interception., Statement of Significance: NR2F1 epigenetically suppresses genes associated with G-protein signaling, cell cycle, and YAP1/TEAD1 pathways, inducing dormancy in uveal melanoma (UM) disseminated cancer cells. This study unveils novel markers for UM dormancy and reactivation, positioning NR2F1 as a promising target for intercepting residual and UM metastatic disease.

CD44 has been described in many malignancies as a marker of cancer stem cells (CSCs). Several techniques can be used to detect these cells. Here we detail CD44 detection by flow cytometry, a precise technique allowing to determine the percentage of positive cells and the mean fluorescent intensity reflecting the CD44 expression by cells in the samples. The protocol explained here can be used to detect CD44 from cell suspensions prepared from tissues or in vitro cell cultures., (© 2024. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)