Project description:ChIP-Seq for H3K27 trimethylation was performed for two HPV-positive and two HPV-negative squamous cell carcinoma cell lines. The data served two purposes. First, the data were used as an example implementation of our novel ChIP-Seq Peak Prioritization pipeline, PePr. We have developed the PePr pipeline, a ChIP-Seq Peak Prioritization pipeline that accounts for the variation among replicates and peak location relative to a gene. We show, using a transcription factor dataset (which exhibited small variation among samples), that PePr performs favorably compared to commonly used peak callers and that it achieves balanced sensitivity and specificity. We also show, using histone modification data (which exhibited larger variation among samples), that PePr can improve the detection of differential H3K27me3 regions compared with a common current approach. Using data from ChIP-Seq and gene expression experiments performed in parallel on the same samples, we show that the incorporation of functional annotations can improve the prioritization of functional sites. Secondly, the data were used to assess real differences in the genome-wide H3K27me3 profiles between HPV-positive and HPV-negative carcinoma cell lines. Careful analysis and integration of the data with DNA methylation and gene expression data performed on the same cell lines demonstrated striking differences exist. ChIP-Seq for H3K27 trimethylation was performed for two HPV-positive and two HPV-negative squamous cell carcinoma (SCC) cell lines. Input DNA was also sequenced for each sample to serve as a control. The goal was to determine overall differences in H3K27me3 patterns observed between the HPV-positive and HPV-negative SCC cell lines.
Project description:Human papillomavirus (HPV)-associated head and neck cancers (HNSCCs) have a distinct risk profile and appreciate a prognostic advantage compared to HPV-negative HNSCC. Promoter hypermethylation has been widely recognized as an important mechanism in the progression of HNSCC, but the extent to which this mechanism is consistent between HPV(+) and HPV(-) tumors is unknown. To assess the genome-wide methylation changes in HPV(+) and HPV(-) tumors, we analyzed DNA methylation and expression patterns in two HPV(+) and two HPV(-) cell lines. HPV(+) tumors have overall higher DNA methylation in genic and LINE1 regions than HPV(-) tumors, and polycomb repressive complex 2 (PRC2) targets tend to be much more highly methylated in HPV(+) cells. Bisulphite-converted DNA from 4 squamous cell carcinoma (SCC) cell lines were hybridized to the Illumina Infinium 27k Human Methylation Beadchip.
Project description:Human cancer cell lines are the most frequently used preclinical models in the study of cancer biology and the development of therapeutics. Although anatomically diverse, human papillomavirus (HPV)-driven cancers have a common etiology and similar mutations that overlap with but are distinct from those found in HPV-negative cancers. Building on prior studies that have characterized subsets of head and neck squamous cell carcinoma (HNSCC) and cervical squamous cell carcinoma (CESC) cell lines separately, we performed genomic, viral gene expression, and viral integration analyses on 74 cell lines that include all readily-available HPV-positive (9 HNSCC, 8 CESC) and CESC (8 HPV-positive, 2 HPV-negative) cell lines and 55 HPV-negative HNSCC cell lines. We used over 700 human tumors for comparison. Mutation patterns in the cell lines were similar to those of human tumors. We confirmed HPV viral protein and mRNA expression in the HPV-positive cell lines. We found HPV types in three CESC cell lines that are distinct from those previously reported. We found that cell lines and tumors had similar patterns of viral gene expression; there were few sites of recurrent HPV integration. As seen in tumors, HPV integration did appear to alter host gene expression in cell lines. The HPV-positive cell lines had higher levels of p16 and lower levels of Rb protein expression than did the HPV-negative lines. Although the number of HPV-positive cell lines is limited, our results suggest that these cell lines represent suitable models for studying HNSCC and CESC, both of which are common and lethal.
Project description:<p>Head and neck squamous cell carcinoma (HNSCC) is the sixth leading cancer by incidence worldwide(1). Various chemical carcinogens (tobacco, alcohol and betel nut), human papillomavirus (HPV) infection, and genetic predisposition contribute to the etiology of HNSCC, and to the complex genetic alterations in tumor subsets that differ in prognosis and response to therapies (2).</p> <p>Recently, a comprehensive landscape of genomic and transcriptomic alterations in HNSCC tumors has emerged from The Cancer Genome Atlas (TCGA) Network (3). TCGA revealed novel and previously recognized gene and chromosomal region copy number alterations (CNAs), mutations, and expression clusters, and defined their frequency, co-occurrence, and relationship to common and rare subtypes of HPV(-) and (+) tumors that vary in prognosis. To identify cell line models for determining the functional role and therapeutic importance of these alterations, we are performing whole exome and RNA sequencing and bioinformatic analysis of an expanded panel of 15 HPV(-) and 11 HPV(+) HNSCC cell lines and primary oral keratinocytes.</p> <p>We find that the recurrent genomic alterations in cell lines are remarkably consistent with those found in more aggressive tumors, from which cell lines have traditionally been most readily adapted to culture (4). Genome-wide correlation of CN (copy number) with expression identified a suite of potential drivers or modifier genes that differ by HPV status, and are of potential biologic and therapeutic relevance. Further, our findings elucidate and validate genomic alterations underpinning numerous discoveries made with these widely-used and recently derived HNSCC lines, and provide a roadmap for their potential use as models for future studies of tumor subtypes with worse prognosis.</p> <p>References</p> <p> <ol> <li>Torre LA, Bray F, Siegel RL, Ferlay J, Lortet-Tieulent J, Jemal A. Global cancer statistics, 2012. CA Cancer J Clin. 2015;65(2):87-108.</li> <li>Van Waes C, Musbahi O. Genomics and advances towards precision medicine for head and neck squamous cell carcinoma. Laryngoscope Investig Otolaryngol. 2017;2(5):310-9.</li> <li>Cancer Genome Atlas N. Comprehensive genomic characterization of head and neck squamous cell carcinomas. Nature. 2015;517(7536):576-82.</li> <li>White JS, Weissfeld JL, Ragin CC, Rossie KM, Martin CL, Shuster M, et al. The influence of clinical and demographic risk factors on the establishment of head and neck squamous cell carcinoma cell lines. Oral Oncol. 2007;43(7):701-12.</li> </ol> </p>
Project description:Persistent infection by high-risk human papillomaviruses (HPVs) is associated with the development of cervical cancer and a subset of anogenital and head and neck squamous cell carcinomas. Abnormal expression of cellular microRNAs (miRNAs) plays an important role in the development of cancer, including HPV-related tumors. MiRNA expression profile was investigated by microrray analysis in the HPV-positive cervical cancer cell lines SiHa (HPV16-positive cell line derived from a cervical squamous cell carcinoma), CaSki (HPV16-positive cell line derived from a metastatic cervical epidermoid carcinoma), and HeLa (HPV18-positive cell line derived from a cervical adenocarcinoma) and compared with primary HFKs and C33a (HPV-negative cervical cell line).
Project description:Genome wide DNA methylation profiling of primary penile squamous cell carcinoma samples with lymphnode metastasis. The Illumina Infinium 450 K Human Methylation was used to obtain DNA methylation profiles in surgical frozen samples. Among the 25 samples, fifteen was infected with HPV, and the others were HPV negative.
Project description:Chromatin alterations mediate mutations and gene expression changes in cancer. Chromatin immunoprecipitation followed by sequencing (ChIP-Seq) has been utilized to study genome-wide chromatin structure in human cancer cell lines, yet numerous technical challenges limit comparable analyses in primary tumors. Here we have developed a new whole-genome analytic pipeline to optimize ChIP-Seq protocols on patient-derived xenografts from human papillomavirus-related (HPV+) head and neck squamous cell carcinoma (HNSCC) samples. We further associated chromatin aberrations with gene expression changes from a larger cohort of the tumor and normal samples with RNA-Seq data. We detect differential histone enrichment associated with tumor-specific gene expression variation, sites of HPV integration in the human genome, and HPV-associated histone enrichment sites upstream of cancer driver genes, which play central roles in cancer-associated pathways. These comprehensive analyses enable unprecedented characterization of the complex network of molecular changes resulting from chromatin alterations that drive HPV-related tumorigenesis.