RESUMO
Aberrant expression of microRNAs (miRNAs) and the enzymes that control their processing have been reported in multiple biological processes including primary and metastatic tumours, but the mechanisms governing this are not clearly understood. Here we show that TAp63, a p53 family member, suppresses tumorigenesis and metastasis, and coordinately regulates Dicer and miR-130b to suppress metastasis. Metastatic mouse and human tumours deficient in TAp63 express Dicer at very low levels, and we found that modulation of expression of Dicer and miR-130b markedly affected the metastatic potential of cells lacking TAp63. TAp63 binds to and transactivates the Dicer promoter, demonstrating direct transcriptional regulation of Dicer by TAp63. These data provide a novel understanding of the roles of TAp63 in tumour and metastasis suppression through the coordinate transcriptional regulation of Dicer and miR-130b and may have implications for the many processes regulated by miRNAs.
Assuntos
RNA Helicases DEAD-box/metabolismo , Endorribonucleases/metabolismo , Regulação Neoplásica da Expressão Gênica , MicroRNAs/biossíntese , Metástase Neoplásica/genética , Fosfoproteínas/metabolismo , Ribonuclease III/metabolismo , Transativadores/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Animais , Linhagem Celular , Linhagem Celular Tumoral , Senescência Celular , RNA Helicases DEAD-box/biossíntese , RNA Helicases DEAD-box/deficiência , RNA Helicases DEAD-box/genética , Endorribonucleases/genética , Feminino , Genes Supressores de Tumor/fisiologia , Instabilidade Genômica , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , MicroRNAs/genética , MicroRNAs/metabolismo , Neoplasias/genética , Neoplasias/metabolismo , Neoplasias/patologia , Fosfoproteínas/deficiência , Fosfoproteínas/genética , Regiões Promotoras Genéticas/genética , Ribonuclease III/biossíntese , Ribonuclease III/deficiência , Ribonuclease III/genética , Transativadores/deficiência , Transativadores/genética , Fatores de Transcrição , Ativação Transcricional , Proteínas Supressoras de Tumor/deficiência , Proteínas Supressoras de Tumor/genéticaRESUMO
MOTIVATION: Tissue samples of tumor cells mixed with stromal cells cause underdetection of gene expression signatures associated with cancer prognosis or response to treatment. In silico dissection of mixed cell samples is essential for analyzing expression data generated in cancer studies. Currently, a systematic approach is lacking to address three challenges in computational deconvolution: (i) violation of linear addition of expression levels from multiple tissues when log-transformed microarray data are used; (ii) estimation of both tumor proportion and tumor-specific expression, when neither is known a priori; and (iii) estimation of expression profiles for individual patients. RESULTS: We have developed a statistical method for deconvolving mixed cancer transcriptomes, DeMix, which addresses the aforementioned issues in array-based expression data. We demonstrate the performance of our model in synthetic and real, publicly available, datasets. DeMix can be applied to ongoing biomarker-based clinical studies and to the vast expression datasets previously generated from mixed tumor and stromal cell samples. AVAILABILITY: All codes are written in C and integrated into an R function, which is available at http://odin.mdacc.tmc.edu/â¼wwang7/DeMix.html. CONTACT: wwang7@mdanderson.org SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.
Assuntos
Perfilação da Expressão Gênica/métodos , Neoplasias/genética , Algoritmos , Animais , Simulação por Computador , Humanos , RatosRESUMO
INTRODUCTION: Malignant pleural mesothelioma (MPM) is a deadly disease with poor prognosis and few treatment options. We characterized and elucidated the roles of C-MYC and PVT1 involved in the pathogenesis of MPM. METHODS: We used small interfering RNA (siRNA)-mediated knockdown in MPM cell lines to determine the effect of C-MYC and PVT1 abrogation on MPM cells undergoing apoptosis, proliferation, and cisplatin sensitivity. We also characterized the expression of microRNAs spanning the PVT1 region in MPM cell lines. Copy number analysis was measured by quantitative polymerase chain reaction and fluorescence in situ hybridization. RESULTS: Copy number analysis revealed copy number gains (CNGs) in chromosomal region 8q24 in six of 12 MPM cell lines. MicroRNA analysis showed high miR-1204 expression in MSTO-211H cell lines with four copies or more of PVT1. Knockdown by siRNA showed increased PARP-C levels in MSTO-211H transfected with siPVT1 but not in cells transfected with siC-MYC. C-MYC and PVT1 knockdown reduced cell proliferation and increased sensitivity to cisplatin. Analysis of the expression of apoptosis-related genes in the MSTO-211H cell line suggested that C-MYC maintains a balance between proapoptotic and antiapoptotic gene expression, whereas PVT1 and, to a lesser extent, miR-1204 up-regulate proapoptotic genes and down-regulate antiapoptotic genes. Fluorescence in situ hybridization analysis of MPM tumor specimens showed a high frequency of both CNGs (11 of 75) and trisomy (three copies; 11 of 75) for the C-MYC locus. CONCLUSION: Our results suggest that C-MYC and PVT1 CNG promotes a malignant phenotype of MPM, with C-MYC CNG stimulating cell proliferation and PVT1 both stimulating proliferation and inhibiting apoptosis.