Microarray Samples for shTP63 in Immortalized HFK to Investigate How ACTL6A and p63 Activate Hippo-YAP in SCC

Loss-of-function mutations in SWI/SNF chromatin remodeling subunit genes are observed in many cancers, but an oncogenic role for SWI/SNF is not well established. Here we reveal that ACTL6A, encoding a SWI/SNF subunit linked to stem and progenitor cell function, is frequently co-amplified and highly expressed together with the p53 family member p63 in head and neck squamous cell carcinoma (HNSCC). ACTL6A and p63 physically interact and cooperatively control a transcriptional program that promotes proliferation and suppresses differentiation, in part through activation of the Hippo-YAP pathway via regulators including WWC1. Consequently, loss of ACTL6A or p63 in tumor cells induces YAP phosphorylation and inactivation, associated with growth arrest and terminal differentiation, all phenocopied by WWC1 overexpression. In vivo, ectopic ACTLC6A/p63 expression promotes tumorigenesis, while ACTL6A expression and YAP activation are highly correlated in primary HNSCC and predict poor patient survival. Thus, ACTL6A and p63 collaborate as oncogenic drivers in HNSCC.

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Saladi SV, Ross K, Karaayvaz M, Tata PR, Mou H, Rajagopal J, Ramaswamy S, Ellisen LW