Project description:Lung cancer is the leading cause of cancer-related deaths worldwide. The paralogous transcriptional cofactors Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ, also called WWTR1), the main downstream effectors of the Hippo signal transduction pathway, are emerging as pivotal determinants of malignancy in lung cancer. Traditionally, studies have tended to consider YAP and TAZ as functionally redundant transcriptional cofactors with similar biological impact. However, there is growing evidence that each of them also possesses distinct attributes. Here we sought to systematically characterize the division of labor between YAP and TAZ in non-small cell lung cancer (NSCLC), the most common histological subtype of lung cancer. Representative NSCLC cell lines as well as patient-derived data showed that the two paralogs orchestrated nonoverlapping transcriptional programs in this cancer type. YAP preferentially regulated gene sets associated with cell division and cell-cycle progression, whereas TAZ preferentially regulated genes associated with extracellular matrix organization. Depletion of YAP resulted in growth arrest, whereas its overexpression promoted cell proliferation. Likewise, depletion of TAZ compromised cell migration, whereas its overexpression enhanced migration. The differential effects of YAP and TAZ on key cellular processes were also associated with differential response to anticancer therapies. Uncovering the different activities and downstream effects of YAP and TAZ may thus facilitate better stratification of patients with lung cancer for anticancer therapies. SIGNIFICANCE: Thease findings show that oncogenic paralogs YAP and TAZ have distinct roles in NSCLC and are associated with differential response to anticancer drugs, knowledge that may assist lung cancer therapy decisions.
Project description:The paralogous transcriptional cofactors Yes-associated protein (YAP) and transcriptional co-activator with PDZ-binding motif (TAZ, also called WWTR1), the main downstream effectors of the Hippo signal transduction pathway, are emerging as pivotal determinants of malignancy in lung cancer. Traditionally, studies have tended to consider YAP and TAZ as functionally redundant transcriptional cofactors, with similar biological impact. However, there is growing evidence that each of them also possesses distinct attributes. We sought to systematically characterize the division of labor between YAP and TAZ in non-small cell lung cancer (NSCLC), the most common histological subtype of lung cancer. We showed that the two paralogs orchestrate non-overlapping transcription programs in this cancer type.
Project description:The paralogous transcriptional cofactors Yes-associated protein (YAP) and transcriptional co-activator with PDZ-binding motif (TAZ, also called WWTR1), the main downstream effectors of the Hippo signal transduction pathway, are emerging as pivotal determinants of malignancy in lung cancer. Traditionally, studies have tended to consider YAP and TAZ as functionally redundant transcriptional cofactors, with similar biological impact. However, there is growing evidence that each of them also possesses distinct attributes. We sought to systematically characterize the division of labor between YAP and TAZ in non-small cell lung cancer (NSCLC), the most common histological subtype of lung cancer. We showed that the two paralogs orchestrate non-overlapping transcription programs in this cancer type.
Project description:Long non-coding RNAs (lncRNAs) regulate numerous biological processes involved in both development and carcinogenesis. Hippo-YAP/TAZ signaling, a critical pathway responsible for organ size control, is often dysregulated in a variety of cancers. However, the nature and function of YAP/TAZ-regulated lncRNAs during tumorigenesis remain largely unexplored. By profiling YAP/TAZ-regulated lncRNAs, we identified SFTA1P as a novel transcriptional target and a positive feedback regulator of YAP/TAZ signaling. Using non-small cell lung cancer (NSCLC) cell lines, we show that SFTA1P is transcriptionally activated by YAP/TAZ in a TEAD-dependent manner. Functionally, knockdown of SFTA1P in NSCLC cell lines inhibited proliferation, induced programmed cell death, and compromised their tumorigenic potential. Mechanistically, SFTA1P knockdown decreased TAZ protein abundance and consequently, the expression of YAP/TAZ transcriptional targets. We provide evidence that this phenomenon could potentially be mediated via its interaction with TAZ mRNA to regulate TAZ translation. Our results reveal SFTA1P as a positive feedback regulator of Hippo-YAP/TAZ signaling, which may serve as the molecular basis for lncRNA-based therapies against YAP/TAZ-driven cancers.
Project description:Small cell lung cancer (SCLC) is a highly aggressive and metastatic malignancy that shows rapid development of chemoresistance and a high rate of recurrence. Recent genome and transcriptome studies have provided the whole landscape of genomic alterations and gene expression changes in SCLC. In light of the inter-individual heterogeneity of SCLC, subtyping of SCLC might be helpful for prediction of therapeutic response and prognosis. Based on the transcriptome data of SCLC cell lines, we undertook transcriptional network-defined SCLC classification and identified a unique SCLC subgroup characterized by relatively high expression of Hippo pathway regulators Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ) (YAP/TAZ subgroup). The YAP/TAZ subgroup displayed adherent cell morphology, lower expression of achaete-scute complex homolog 1 (ASCL1) and neuroendocrine markers, and higher expression of laminin and integrin. YAP knockdown caused cell morphological alteration reminiscent of floating growth pattern in many SCLC cell lines, and microarray analyses revealed a subset of genes regulated by YAP, including Ajuba LIM protein (AJUBA). AJUBA also contributed to cell morphology regulation. Of clinical importance, SCLC cell lines of the YAP/TAZ subgroup showed unique patterns of drug sensitivity. Our findings shed light on a subtype of SCLC with YAP and TAZ expression, and delineate molecular networks underlying the heterogeneity of SCLC.
Project description:The Hippo-YAP/TAZ signaling pathway is an evolutionarily conserved signaling pathway involved in a broad spectrum of biological processes, including tumorigenesis. Whilst aberrant Hippo-YAP/TAZ signaling is frequently reported in various cancers, the genetic alterations of this pathway are relatively rare, suggesting regulation at the post-transcriptional level. MicroRNAs play key role in tumorigenesis by regulating gene expression post-transcriptionally. Amongst the cancer-relevant microRNAs, miR-582-5p suppresses cell growth and tumorigenesis by inhibiting the expression of oncogenes, including AKT3, MAP3K2 and NOTCH1. Given the oncogenic role of YAP/TAZ in solid tumors, we scrutinized the possible interplay between miR-582-5p and Hippo-YAP/TAZ signaling. Correlation analysis in NSCLC cells revealed a positive relationship between the expression of mature miR-582-5p and the proportion of phosphorylated YAP/TAZ. Intriguingly, YAP/TAZ knockdown reduced the expression of mature miR-582-5p but increased that of primary miR-582. Overexpression of miR-582-5p resulted in increased phosphorylation of YAP/TAZ with a concomitant reduction in cell proliferation and enhanced apoptosis. Mechanistically, we find that miR-582-5p targets actin regulators NCKAP1 and PIP5K1C, which may be responsible for the observed alteration in F-actin, known to modulate YAP/TAZ. We postulate that regulation of the actin cytoskeleton by miR-582-5p may attenuate YAP/TAZ activity. Altogether, this study reveals a novel mechanism of YAP/TAZ regulation by miR-582-5p in a cytoskeleton-dependent manner and suggests a negative feedback loop, highlighting the therapeutic potential of restoring miR-582-5p expression in treating NSCLC.
Project description:Lung cancer is the leading cause of cancer death in the world and there is no current treatment able to efficiently treat the disease as the tumor is often diagnosed at an advanced stage. Moreover, cancer cells are often resistant or acquire resistance to the treatment. Further knowledge of the mechanisms driving lung tumorigenesis, aggressiveness, metastasization, and resistance to treatments could provide new tools for detecting the disease at an earlier stage and for a better response to therapy. In this scenario, Yes Associated Protein (YAP) and Trascriptional Coactivator with PDZ-binding motif (TAZ), the final effectors of the Hippo signaling transduction pathway, are emerging as promising therapeutic targets. Here, we will discuss the most recent advances made in YAP and TAZ biology in lung cancer and, more importantly, on the newly discovered mechanisms of YAP and TAZ inhibition in lung cancer as well as their clinical implications.