Project description:This SuperSeries is composed of the following subset Series: GSE25083: Global hypomethylation identifies loci targeted for hypermethylation in head and neck cancer: normal head and neck tissue GSE25089: Global hypomethylation identifies loci targeted for hypermethylation in head and neck cancer: HNSCC GSE25091: Global hypomethylation identifies loci targeted for hypermethylation in head and neck cancer: blood controls Refer to individual Series
Project description:Rap1GAP is a critical tumor suppressor gene that is down-regulated in multiple aggressive cancers such as head and neck squamous cell carcinoma, melanoma and pancreatic cancer. However, the mechanistic basis of rap1GAP down-regulation in cancers is poorly understood. By employing an integrative approach, we demonstrate polycomb-mediated repression of rap1GAP that involves EZH2, a histone methyltransferase in head and neck cancers. We further concomitant down-regulation of rap1GAP in head and neck cancers. EZH2 represses rap1GAP by facilitating the trimethylation of H3K27, a mark of gene repression, and also hypermethylation of rap1GAP promoter. These results provide a conceptual framework involving a microRNA-oncogene-tumor suppressor axis to understand head and neck cancer progression. OSCC3-siRNA Non-Targeting Vs. siRNA EZH2 with dye-swap, HOK-Adeno CMV Vs. Adeno EZH2.
Project description:Rap1GAP is a critical tumor suppressor gene that is down-regulated in multiple aggressive cancers such as head and neck squamous cell carcinoma, melanoma and pancreatic cancer. However, the mechanistic basis of rap1GAP down-regulation in cancers is poorly understood. By employing an integrative approach, we demonstrate polycomb-mediated repression of rap1GAP that involves EZH2, a histone methyltransferase in head and neck cancers. We further concomitant down-regulation of rap1GAP in head and neck cancers. EZH2 represses rap1GAP by facilitating the trimethylation of H3K27, a mark of gene repression, and also hypermethylation of rap1GAP promoter. These results provide a conceptual framework involving a microRNA-oncogene-tumor suppressor axis to understand head and neck cancer progression.
Project description:This study involves characterization of four head and neck cancer cell lines -- NT8e, OT9, AW13516 and AW8507, established from Indian head and neck cancer patients, using SNP arrays, whole exome and whole transcriptome sequencing.
Project description:Microarrays were used to examine gene expression differences between human head and neck squamous cell carcinoma cell lines (FaDu, UTSCC8, UTSCC42a) grown in culture in comparison to a normal oral epithelial cell line. Gene expression data was integrated with global protein expression of head and neck squamous cell carcinoma cell lines and conditioned media to identify secreted protein markers up-regulated at the mRNA level in cancer cells versus the normal cell line. Total RNA obtained from head and neck squamous cell carcinoma cell lines and a normal oral epithelial cell line
Project description:Dysregulation of the epigenome is a common event in malignancy. However, deciphering the earliest cancer associated epigenetic events remains a challenge. Cancer epigenome studies to date have primarily utilised cancer cell lines or clinical samples, where it is difficult to identify the initial epigenetic lesions from those that occur over time. Here, we analysed the epigenome of normal Human Mammary Epithelial Cells (HMEC) and a matched variant cell population (vHMEC) that has escaped senescence and undergone partial carcinogenic transformation. Using this model system we sought to identify the earliest epigenetic changes that potentially occur during carcinogenesis. First we show that the transcriptome of vHMEC resembles that of basal-like breast cancer. Moreover, in vHMEC there is significant deregulation of MYC, p53, EZH2/polycomb, the Aryl Hydrocarbon Receptor (AHR) and miRNAs-143, 145, 199a and 519a at the transcriptional level. Second, we find that vHMEC exhibit genome-wide changes in DNA methylation affecting key cancer-associated pathways. Hypermethylation predominately impacted gene promoters (particularly those targeted by AHR and TP53) and polycomb associated loci, whereas hypomethylation frequently affected enhancers. Next we show that long range epigenetic deregulation occurred in vHMEC involving concordant change in chromatin modification and gene expression across ~0.5-1Mb regions. Finally, we demonstrate that the DNA methylation changes we observe in vHMECs, occur in basal-like breast cancer (notably FOXA1 hypermethylation).. Overall our results suggest that the first steps of carcinogenesis are associated with a co-ordinated deregulation of DNA methylation and chromatin modification spanning a range of genomic loci potentially targeted by key transcription factors and a corresponding deregulation of transcriptional networks. We sought to study the chromatin modification profile of human mammary epithelial cells (HMEC) and a matched isogenic variant population (vHMEC) utilising ChIP-seq. ChIP was performed against H3K27ac, H3K36me3 and H3K27me3 for a HMEC and vHMEC timpoint in one donor. H3K4me3 CHIP was performed in two donors, which were treated as biological replicates.