RESUMO
Aberrantly activated Wnt signaling causes cellular transformation that can lead to human colorectal cancer. Wnt signaling is mediated by Lymphoid Enhancer Factor/T-Cell Factor (LEF/TCF) DNA-binding factors. Here we investigate whether altered LEF/TCF expression is conserved in human colorectal tumor sample and may potentially be correlated with indicators of cancer progression. We carried out a meta-analysis of carefully selected publicly available gene expression data sets with paired tumor biopsy and adjacent matched normal tissues from colorectal cancer patients. Our meta-analysis confirms that among the four human LEF/TCF genes, LEF1 and TCF7 are preferentially expressed in tumor biopsies, while TCF7L2 and TCF7L1 in normal control tissue. We also confirm positive correlation of LEF1 and TCF7 expression with hallmarks of active Wnt signaling (i.e., AXIN2 and LGR5). We are able to correlate differential LEF/TCF gene expression with distinct transcriptomes associated with cell adhesion, extracellular matrix organization, and Wnt receptor feedback regulation. We demonstrate here in human colorectal tumor sample correlation of altered LEF/TCF gene expression with quantitatively and qualitatively different transcriptomes, suggesting LEF/TCF-specific transcriptional regulation of Wnt target genes relevant for cancer progression and survival. This bioinformatics analysis provides a foundation for future more detailed, functional, and molecular analyses aimed at dissecting such functional differences.
Assuntos
Adenocarcinoma/genética , Neoplasias Colorretais/genética , Regulação Neoplásica da Expressão Gênica , Fator 1 de Ligação ao Facilitador Linfoide/biossíntese , Proteínas de Neoplasias/biossíntese , Proteína 1 Semelhante ao Fator 7 de Transcrição/biossíntese , Proteína 2 Semelhante ao Fator 7 de Transcrição/biossíntese , Transcriptoma , Via de Sinalização Wnt , Adenocarcinoma/patologia , Proteína Axina/biossíntese , Proteína Axina/genética , Biópsia , Neoplasias Colorretais/patologia , Mineração de Dados , Conjuntos de Dados como Assunto , Progressão da Doença , Retroalimentação Fisiológica , Humanos , Fator 1 de Ligação ao Facilitador Linfoide/genética , Proteínas de Neoplasias/genética , Isoformas de Proteínas/biossíntese , Isoformas de Proteínas/genética , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , RNA Neoplásico/biossíntese , RNA Neoplásico/genética , Proteína 1 Semelhante ao Fator 7 de Transcrição/genética , Proteína 2 Semelhante ao Fator 7 de Transcrição/genéticaRESUMO
Osteoblasts can be derived from embryonic stem cells (ESCs) by a 30 day differentiation process, whereupon cells spontaneously differentiate upon removal of LIF and respond to exogenously added 1,25α(OH)2 vitamin D3 with enhanced matrix mineralization. However, bone is a load-bearing tissue that has to perform under dynamic pressure changes during daily movement, a capacity that is executed by osteocytes. At present, it is unclear whether ESC-derived osteogenic cultures contain osteocytes and whether these are capable of responding to a relevant cyclic hydrostatic compression stimulus. Here, we show that ESC-osteoblastogenesis is followed by the generation of osteocytes and then mechanically load ESC-derived osteogenic cultures in a compression chamber using a cyclic loading protocol. Following mechanical loading of the cells, iNOS mRNA was upregulated 31-fold, which was consistent with a role for iNOS as an immediate early mechanoresponsive gene. Further analysis of matrix and bone-specific genes suggested a cellular response in favor of matrix remodeling. Immediate iNOS upregulation also correlated with a concomitant increase in Ctnnb1 and Tcf7l2 mRNAs along with increased nuclear TCF transcriptional activity, while the mRNA for the repressive Tcf7l1 was downregulated, providing a possible mechanistic explanation for the noted matrix remodeling. We conclude that ESC-derived osteocytes are capable of responding to relevant mechanical cues, at least such that mimic oscillatory compression stress, which not only provides new basic understanding, but also information that likely will be important for their use in cell-based regenerative therapies.
Assuntos
Osso e Ossos/patologia , Células-Tronco Embrionárias/citologia , Osteócitos/citologia , Animais , Calcitriol/química , Diferenciação Celular , Força Compressiva , Regulação para Baixo , Desenho de Equipamento , Pressão Hidrostática , Camundongos , Óxido Nítrico Sintase Tipo II/metabolismo , Oscilometria , Osteoblastos/citologia , Medicina Regenerativa , Estresse Mecânico , Fatores de Tempo , Proteína 1 Semelhante ao Fator 7 de Transcrição/biossíntese , Regulação para Cima , Suporte de Carga , beta Catenina/biossínteseRESUMO
T-cell factor 3 (TCF3), a downstream effector of Wnt signaling in embryonic stem (ES) cells, plays an important role in pluripotent self-renewal and proliferation. Loss of TCF3 delays the differentiation of mouse ES cells. The purpose of this study was to investigate the effect of TCF3 on embryonal carcinoma (EC). The mouse F9 EC cell line and a tumor-bearing mouse model were used to evaluate the anti-EC tumor effects of TCF3 in vitro and in vivo, respectively. The overexpression of TCF3 significantly inhibited proliferation, colony-forming and migration in F9 EC cells by approximately 30, 45 and 30%, respectively. The in vivo mouse model showed that the overexpression of TCF3 significantly reduced tumor volume (36.4%) and tumor weight (34.8%), malignancy progression and local infiltration and prolonged the life span of tumor-bearing mice. Overexpression of TCF3 significantly down-regulated Oct4 expression in the F9 EC cells. The results indicate that TCF3 is an inhibitor of the malignant phenotypes of embryonal carcinoma through the regulation of Oct4 expression.
