RESUMEN
Special AT-rich sequence binding protein-2 (SATB2) is a nuclear matrix protein that binds to nuclear attachment regions and is involved in chromatin remodeling and transcription regulation. In stem cells, it regulates the expression of genes required for maintaining pluripotency and self-renewal and epithelial-mesenchymal transition (EMT). In this study, we examined the oncogenic role of SATB2 in prostate cancer and assessed whether overexpression of SATB2 in human normal prostate epithelial cells (PrECs) induces properties of cancer stem cells (CSCs). The results demonstrate that SATB2 is highly expressed in prostate cancer cell lines and CSCs, but not in PrECs. Overexpression of SATB2 in PrECs induces cellular transformation which was evident by the formation of colonies in soft agar and spheroids in suspension. Overexpression of SATB2 in PrECs also resulted in induction of stem cell markers (CD44 and CD133), pluripotency-maintaining transcription factors (cMYC, OCT4, SOX2, KLF4, and NANOG), CADHERIN switch, and EMT-related transcription factors. Chromatin immunoprecipitation assay demonstrated that SATB2 can directly bind to promoters of BCL-2, BSP, NANOG, MYC, XIAP, KLF4, and HOXA2, suggesting SATB2 is capable of directly regulating pluripotency/self-renewal, cell survival, and proliferation. Since prostate CSCs play a crucial role in cancer initiation, progression, and metastasis, we also examined the effects of SATB2 knockdown on stemness. SATB2 knockdown in prostate CSCs inhibited spheroid formation, cell viability, colony formation, cell motility, migration, and invasion compared to their scrambled control groups. SATB2 knockdown in CSCs also upregulated the expression of E-CADHERIN and inhibited the expression of N-CADHERIN, SNAIL, SLUG, and ZEB1. The expression of SATB2 was significantly higher in prostate adenocarcinoma compared to normal tissues. Overall, our data suggest that SATB2 acts as an oncogenic factor where it is capable of inducing malignant changes in PrECs by inducing CSC characteristics.
Asunto(s)
Transición Epitelial-Mesenquimal , Factor 4 Similar a Kruppel , Proteínas de Unión a la Región de Fijación a la Matriz , Neoplasias de la Próstata , Factores de Transcripción , Humanos , Masculino , Transición Epitelial-Mesenquimal/genética , Neoplasias de la Próstata/patología , Neoplasias de la Próstata/metabolismo , Neoplasias de la Próstata/genética , Factor 4 Similar a Kruppel/metabolismo , Proteínas de Unión a la Región de Fijación a la Matriz/metabolismo , Proteínas de Unión a la Región de Fijación a la Matriz/genética , Factores de Transcripción/metabolismo , Factores de Transcripción/genética , Línea Celular Tumoral , Células Madre Neoplásicas/metabolismo , Células Madre Neoplásicas/patología , Regulación Neoplásica de la Expresión Génica , Autorrenovación de las Células , Proliferación CelularRESUMEN
The RNA-binding protein PNO1 plays an essential role in ribosome biogenesis. Recent studies have shown that it is involved in tumorigenesis; however, its role in hepatocellular carcinoma (HCC) is not well understood. The purpose of this study was to examine whether PNO1 can be used as a biomarker of HCC and also examine the therapeutic potential of PNO1 knockout for the treatment of HCC. PNO1 expression was upregulated in HCC and associated with poor prognosis. PNO1 expression was positively associated with tumour stage, lymph node metastasis and poor survival. PNO1 expression was significantly higher in HCC compared to that in fibrolamellar carcinoma or normal tissues. Furthermore, HCC tissues with mutant Tp53 expressed higher PNO1 than those with wild-type Tp53. PNO1 knockout suppressed cell viability, colony formation and EMT of HCC cells. Since activation of Notch signalling pathway promotes HCC, we measured the effects of PNO1 knockout on the components of Notch pathway and its targets. PNO1 knockout suppressed Notch signalling by modulating the expression of Notch ligands and their receptors, and downstream targets. PNO1 knockout also inhibited genes involved in surface adhesion, cell cycle, inflammation and chemotaxis. PNO1 knockout also inhibited colony and spheroid formation, cell migration and invasion, and markers of stem cells, pluripotency and EMT in CSCs. Overall, our data suggest that PNO1 can be used as a diagnostic and prognostic biomarker of HCC, and knockout of PNO1 by CRISPR/Cas9 can be beneficial for the management of HCC by targeting CSCs.
Asunto(s)
Biomarcadores de Tumor , Carcinoma Hepatocelular , Regulación Neoplásica de la Expresión Génica , Neoplasias Hepáticas , Proteínas de Unión al ARN , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patología , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patología , Biomarcadores de Tumor/metabolismo , Biomarcadores de Tumor/genética , Masculino , Proteínas de Unión al ARN/metabolismo , Proteínas de Unión al ARN/genética , Línea Celular Tumoral , Femenino , Pronóstico , Persona de Mediana Edad , Transducción de Señal , Proteína p53 Supresora de Tumor/metabolismo , Proteína p53 Supresora de Tumor/genética , Receptores Notch/metabolismo , Receptores Notch/genética , Movimiento Celular/genética , Células Madre Neoplásicas/metabolismo , Células Madre Neoplásicas/patología , Transición Epitelial-Mesenquimal/genética , Proliferación Celular , Relevancia ClínicaRESUMEN
Growth is crucially controlled by the functional ribosomes available in cells. To meet the enhanced energy demand, cancer cells re-wire and increase their ribosome biogenesis. The RNA-binding protein PNO1, a ribosome assembly factor, plays an essential role in ribosome biogenesis. The purpose of this study was to examine whether PNO1 can be used as a biomarker for lung adenocarcinoma and also examine the molecular mechanisms by which PNO1 knockdown by CRISPR/Cas9 inhibited growth and epithelial-mesenchymal transition (EMT). The expression of PNO1 was significantly higher in lung adenocarcinoma compared to normal lung tissues. PNO1 expression in lung adenocarcinoma patients increased with stage, nodal metastasis, and smoking. Lung adenocarcinoma tissues from males expressed higher PNO1 than those from females. Furthermore, lung adenocarcinoma tissues with mutant Tp53 expressed higher PNO1 than those with wild-type Tp53, suggesting the influence of Tp53 status on PNO1 expression. PNO1 knockdown inhibited cell viability, colony formation, and EMT, and induced apoptosis. Since dysregulated signalling through the Notch receptors promotes lung adenocarcinoma, we measured the effects of PNO1 inhibition on the Notch pathway. PNO1 knockdown inhibited Notch signalling by suppressing the expression of Notch receptors, their ligands, and downstream targets. PNO1 knockdown also suppressed CCND1, p21, PTGS-2, IL-1α, IL-8, and CXCL-8 genes. Overall, our data suggest that PNO1 can be used as a diagnostic biomarker, and also can be an attractive therapeutic target for the treatment of lung adenocarcinoma.
