Project description:When cells are exposed to x-irradiation, they go through two-step malignant transformation. The exposure of x-irradiation is considered as the first step, and in this study, we are here to elucidate what happens in the second step using bulk RNA sequencing, whole-genome sequencing, and single cell RNA sequencing.
Project description:How malignant gliomas arise in a mature brain remains a mystery, hindering the development of preventive and therapeutic interventions. We previously showed that oligodendrocyte precursor cells (OPCs) can be transformed into glioma when mutations are introduced perinatally. However, adult OPCs rarely proliferate compared to their perinatal counterparts. Whether these relatively quiescent cells have the potential to transform is unknown, which is a critical question considering the late onset of human glioma. Additionally, the events taking place between initial mutation and a fully developed tumor mass (pre-malignant phase) are particularly poorly understood in glioma. Here we used a temporally controllable Cre transgene to delete p53 and NF1 specifically in adult OPCs, and demonstrated that these cells consistently give rise to malignant gliomas. To investigate the transforming process of quiescent adult OPCs, we then tracked these cells throughout the pre-malignant phase, which revealed a dynamic multi-step transformation, starting with rapid but transient hyper-proliferative reactivation, followed by a long period of dormancy, then final malignant transformation. Using pharmacological approaches, we discovered that mTOR signaling is critical for both the initial OPC reactivation step and late stage tumor cell proliferation, and thus might be a potential target for both glioma prevention and treatment. In summary, our results firmly establish the transforming potential of adult OPCs, and reveal an actionable multi-phasic reactivation process that turns slowly dividing OPCs into malignant gliomas. 44K Mouse Development Oligo Microarrays from Agilent Technologies were used for microarray analysis. For each experiment, total RNA was fluorescently labeled and hybridized directly against a common reference sample generated from the RNA pool of four WT P17 mouse brain neocortex.
Project description:How malignant gliomas arise in a mature brain remains a mystery, hindering the development of preventive and therapeutic interventions. We previously showed that oligodendrocyte precursor cells (OPCs) can be transformed into glioma when mutations are introduced perinatally. However, adult OPCs rarely proliferate compared to their perinatal counterparts. Whether these relatively quiescent cells have the potential to transform is unknown, which is a critical question considering the late onset of human glioma. Additionally, the events taking place between initial mutation and a fully developed tumor mass (pre-malignant phase) are particularly poorly understood in glioma. Here we used a temporally controllable Cre transgene to delete p53 and NF1 specifically in adult OPCs, and demonstrated that these cells consistently give rise to malignant gliomas. To investigate the transforming process of quiescent adult OPCs, we then tracked these cells throughout the pre-malignant phase, which revealed a dynamic multi-step transformation, starting with rapid but transient hyper-proliferative reactivation, followed by a long period of dormancy, then final malignant transformation. Using pharmacological approaches, we discovered that mTOR signaling is critical for both the initial OPC reactivation step and late stage tumor cell proliferation, and thus might be a potential target for both glioma prevention and treatment. In summary, our results firmly establish the transforming potential of adult OPCs, and reveal an actionable multi-phasic reactivation process that turns slowly dividing OPCs into malignant gliomas.
Project description:In tumor tissues, hypoxia is a commonly observed feature resulting from rapidly proliferating cancer cells outgrowing the surrounding vasculature network. The four-step isogenic BJ cell model enables studies of defined steps of tumorigenesis: the normal, immortalized, transformed, and metastasizing stages. By transcriptome profiling under atmospheric and moderate hypoxic (3% O2) conditions, we observed that despite being highly similar, the four cell lines responded strikingly different to hypoxia. We demonstrate that the transcriptome adaptation to moderate hypoxia resembles the process of malignant transformation. The transformed cells displayed a distinct capability of metabolic switching, reflected in reversed gene expression patterns for several genes involved in oxidative phosphorylation and glycolytic pathways. By profiling the stage-specific responses to hypoxia, we identified ASS1 as a potential prognostic marker in hypoxic tumors. This study demonstrates the usefulness of the BJ cell model for highlighting the interconnection of pathways involved in malignant transformation and hypoxic response.
Project description:Genome-wide SNP profilling for loss of heterozygosity (LOH) during FOXM1B-induced malignant transformation in a human premalignant oral keratinocyte line SVpgC2a. Keywords: oral cancer, keratinocytes, head and neck squamous cell carcinoma, FOXM1, genomic instability, SNP array, loss of heterozygosity, malignant transformation
Project description:This SuperSeries is composed of the following subset Series: GSE38926: Patterns of aberrant DNA methylation after toxicant-induced malignant transformation (MeDIP-chip dataset 1) GSE38928: Patterns of aberrant DNA methylation after toxicant-induced malignant transformation (MeDIP-chip dataset 2) GSE38929: Patterns of aberrant DNA methylation after toxicant-induced malignant transformation (miRNA dataset) Refer to individual Series
Project description:Arsenic is environmental risk factor and has been linked to urothelial carcinoma incidence. Arsenic exposure-induced malignant transformed cells was established from normal urothelial cells by chronic arsenic exposure for 10 months. The purpose of the present study is to elucidate the relevant molecular alterationon on arsenic-induced malignant transformation.
Project description:A large number of oral squamous cell carcinomas (OSCCs) are believed to be preceded by oral potentially malignant disorders (OPMD) that have an increased likelihood of malignant transformation compared to clinically normal mucosa. This study was performed to identify differentially expressed genes between OPMDs that underwent malignant transformation (MT) and those that did not, termed ‘non-transforming’ (NT) cases. Total RNA was extracted from formalin-fixed paraffin-embedded tissue biopsies of 20 OPMD cases with known clinical outcomes (10 MT vs. 10 NT). Samples were assessed for quantity, quality and integrity of RNA prior to sequencing. Analysis for differential gene expression between MT and NT was performed using statistical packages in R. Genes were considered to be significantly differentially expressed if the False Discovery Rate corrected p-value was < 0.05. RNA yield was variable but RNA purity was good (A260/A280 >1.90). Analysis of RNA-Sequencing outputs revealed 41 genes (34 protein-coding; 7 non-coding) that were significantly differentially expressed between MT and NT cases. The log2 fold change for the statistically significant differentially expressed genes ranged from -2.63 to 2.48, with 23 protein-coding genes being downregulated and 11 protein-coding genes being upregulated in MT cases compared to NT cases. Several candidate genes that may play a role in malignant transformation of OPMD have been identified. Experiments to validate these candidates are underway. It is anticipated that this work will contribute to better understanding of the aetiopathogenesis of OPMD and development of novel biomarkers.
Project description:This SuperSeries is composed of the following subset Series: GSE32727: EMT inducers catalyze malignant transformation of mammary epithelial cells and drive tumorigenesis towards claudin-low tumors [human] GSE32904: EMT inducers catalyze malignant transformation of mammary epithelial cells and drive tumorigenesis towards claudin-low tumors [mouse] Refer to individual Series