RESUMEN
Extensive knowledge has been gained on the transcription network controlled by ERα, however, the mechanism underlying ESR1 (encoding ERα) expression is less understood. We recently discovered that the Hippo pathway is required for the proper expression of ESR1. YAP/TAZ are transcription coactivators that are phosphorylated and inhibited by the Hippo pathway kinase LATS. Here we delineated the molecular mechanisms underlying ESR1 transcription repression by the Hippo pathway. Mechanistically, YAP binds to TEAD to increase local chromatin accessibility to stimulate transcription of nearby genes. Among the YAP target genes, Vestigial-Like Protein 3 (VGLL3) competes with YAP/TAZ for binding to TEAD transcription factor and recruits the NCOR2/SMRT repressor to the super-enhancer of ESR1 gene, leading to epigenetic alteration and transcriptional silencing. We developed a potent LATS inhibitor VT02956. Targeting the Hippo pathway by VT02956 represses ESR1 expression and inhibits the growth of ER+ breast cancer cells as well as patient-derived tumour organoids. Moreover, histone deacetylase inhibitors, such as Entinostat, induce VGLL3 expression to inhibit ER+ breast cancer cells. Our study suggests LATS as unexpected cancer therapeutic targets, especially for endocrine-resistant breast cancers.
Asunto(s)
Neoplasias de la Mama , Receptor alfa de Estrógeno , Vía de Señalización Hippo , Femenino , Humanos , Proteínas Adaptadoras Transductoras de Señales/genética , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Receptor alfa de Estrógeno/genética , Receptor alfa de Estrógeno/metabolismo , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Proteínas Serina-Treonina Quinasas/genética , Proteínas Serina-Treonina Quinasas/metabolismo , Transducción de Señal , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Proteínas Señalizadoras YAP/metabolismoRESUMEN
The Hippo pathway plays a crucial role in organ size control and tumor suppression, but its precise regulation is not fully understood. In this study, we discovered that phosphatidic acid (PA)-related lipid signaling is a key regulator of the Hippo pathway. Supplementing PA in various Hippo-activating conditions activates YAP. This PA-related lipid signaling is involved in Rho-mediated YAP activation. Mechanistically, PA directly interacts with Hippo components LATS and NF2 to disrupt LATS-MOB1 complex formation and NF2-mediated LATS membrane translocation and activation, respectively. Inhibition of phospholipase D (PLD)-dependent PA production suppresses YAP oncogenic activities. PLD1 is highly expressed in breast cancer and positively correlates with YAP activation, suggesting their pathological relevance in breast cancer development. Taken together, our study not only reveals a role of PLD-PA lipid signaling in regulating the Hippo pathway but also indicates that the PLD-PA-YAP axis is a potential therapeutic target for cancer treatment.
Asunto(s)
Metabolismo de los Lípidos/fisiología , Ácidos Fosfatidicos/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Transducción de Señal/fisiología , Secuencia de Aminoácidos , Animales , Neoplasias de la Mama/metabolismo , Línea Celular , Línea Celular Tumoral , Femenino , Células HEK293 , Vía de Señalización Hippo , Humanos , Estimulante Tiroideo de Acción Prolongada/metabolismo , Ratones , Ratones Desnudos , Neurofibromina 2/metabolismo , Proteínas Nucleares/metabolismo , Fosfolipasa D/metabolismo , Fosfoproteínas/metabolismoRESUMEN
The mammalian target of rapamycin (mTOR) promotes anabolic cellular processes in response to growth factors and metabolic cues. The TSC1 and TSC2 tumor suppressors are major upstream inhibitory regulators of mTOR signaling. Mice with Rip2/Cre-mediated deletion of Tsc1 (Rip-Tsc1cKO mice) developed hyperphagia and obesity, suggesting that hypothalamic disruption (for which Rip2/Cre is well known) of Tsc1 may dysregulate feeding circuits via mTOR activation. Indeed, Rip-Tsc1cKO mice displayed increased mTOR signaling and enlarged neuron cell size in a number of hypothalamic populations, including Pomc neurons. Furthermore, Tsc1 deletion with Pomc/Cre (Pomc-Tsc1cKO mice) resulted in dysregulation of Pomc neurons and hyperphagic obesity. Treatment with the mTOR inhibitor, rapamycin, ameliorated the hyperphagia, obesity, and the altered Pomc neuronal morphology in developing or adult Pomc-Tsc1cKO mice, and cessation of treatment reinstated these phenotypes. Thus, ongoing mTOR activation in Pomc neurons blocks the catabolic function of these neurons to promote nutrient intake and increased adiposity.