RESUMO
Mechanisms underpinning airway epithelial homeostatic maintenance and ways to prevent its dysregulation remain elusive. Herein, we identify that ß-catenin phosphorylated at Y489 (p-ß-cateninY489) emerges during human squamous lung cancer progression. This led us to develop a model of airway basal stem cell (ABSC) hyperproliferation by driving Wnt/ß-catenin signaling, resulting in a morphology that resembles premalignant lesions and loss of ciliated cell differentiation. To identify small molecules that could reverse this process, we performed a high-throughput drug screen for inhibitors of Wnt/ß-catenin signaling. Our studies unveil Wnt inhibitor compound 1 (WIC1), which suppresses T-cell factor/lymphoid enhancer-binding factor (TCF/LEF) activity, reduces ABSC proliferation, induces ciliated cell differentiation, and decreases nuclear p-ß-cateninY489. Collectively, our work elucidates a dysregulated Wnt/p-ß-cateninY489 axis in lung premalignancy that can be modeled in vitro and identifies a Wnt/ß-catenin inhibitor that promotes airway homeostasis. WIC1 may therefore serve as a tool compound in regenerative medicine studies with implications for restoring normal airway homeostasis after injury.
Assuntos
Pulmão/efeitos dos fármacos , Pulmão/metabolismo , Células-Tronco/efeitos dos fármacos , Células-Tronco/metabolismo , Proteínas Wnt/antagonistas & inibidores , Via de Sinalização Wnt/efeitos dos fármacos , Animais , Brônquios/citologia , Brônquios/efeitos dos fármacos , Brônquios/metabolismo , Brônquios/patologia , Diferenciação Celular/efeitos dos fármacos , Avaliação Pré-Clínica de Medicamentos/métodos , Feminino , Ensaios de Triagem em Larga Escala/métodos , Homeostase/efeitos dos fármacos , Humanos , Pulmão/citologia , Pulmão/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Lesões Pré-Cancerosas/metabolismo , Lesões Pré-Cancerosas/patologia , Bibliotecas de Moléculas Pequenas/farmacologia , Células-Tronco/citologia , Células-Tronco/patologia , Transfecção , Proteínas Wnt/metabolismo , beta Catenina/antagonistas & inibidores , beta Catenina/metabolismoRESUMO
BACKGROUND: Long non-coding RNAs (lncRNAs) play a variety of cellular roles, including regulation of transcription and translation, leading to alterations in gene expression. Some lncRNAs modulate the expression of chromosomally adjacent genes. Here, we assess the roles of the lncRNA CASC15 in regulation of a chromosomally nearby gene, SOX4, and its function in RUNX1/AML translocated leukemia. RESULTS: CASC15 is a conserved lncRNA that was upregulated in pediatric B-acute lymphoblastic leukemia (B-ALL) with t (12; 21) as well as pediatric acute myeloid leukemia (AML) with t (8; 21), both of which are associated with relatively better prognosis. Enforced expression of CASC15 led to a myeloid bias in development, and overall, decreased engraftment and colony formation. At the cellular level, CASC15 regulated cellular survival, proliferation, and the expression of its chromosomally adjacent gene, SOX4. Differentially regulated genes following CASC15 knockdown were enriched for predicted transcriptional targets of the Yin and Yang-1 (YY1) transcription factor. Interestingly, we found that CASC15 enhances YY1-mediated regulation of the SOX4 promoter. CONCLUSIONS: Our findings represent the first characterization of this CASC15 in RUNX1-translocated leukemia, and point towards a mechanistic basis for its action.