Project description:The inability to establish stable cell lines from the vast majority of human tumors has limited the use of in vitro models to study human cancer. Currently available tumor cell lines fail to represent the biological diversity of human tumors. We have developed a cell culture medium that enabled us to routinely establish cell lines from diverse subtypes of ovarian tumors. Importantly, the twenty-five ovarian tumor cell lines described here retain the genomic landscape, histopathology, and molecular features of the original tumors. Furthermore, the molecular profile and drug response of these cell lines correlated with distinct groups of primary tumors with different outcomes. Thus, tumor cell lines derived using this methodology represent a significantly improved new platform to study human tumor biology and treatment. 41 samples were analyzed in singlicate. DNA was extracted from 16 OCI cell lines and the 16 uncultured tumor tissue samples from which they were derived. DNA was also extracted from 9 standard ovarian cancer cell lines.
Project description:Random monoallelic expression is defined by the allele-specific expression of genes, and by the fact that for an individual cell this monoallelic expression is neither obligate nor necessarily coordinated with the allelic expression in other cells. In order to find novel examples of random monoallelic expression in mouse, we did a transcriptome-wide survey of allele-specific gene expression in two different immortalized cell types. Lymphoblast cell lines and fibroblast cell lines were established (both clonal and nonclonal) and were used as a source of both nuclear RNA and genomic DNA. These samples were assessed for allele-specific gene expression using a custom-designed Mouse SNP Chip. A large number of genes (over 10% of those that were assessed in lymphoblast clones) displayed random monoallelic expression. For each cell line, two replicate samples of ds-cDNA were assessed for monoallelic expression, while genomic DNA was assessed as a control for possible LOH events. Nonclonal samples were used as controls for cis-acting allelic bias.
Project description:Genetic variations play an important role in tumor development and metastasis. Hepatocellular carcinoma (HCC) is one of leading cause of cancer-related death. Despite improvements in surveillance and clinical treatment strategies, the prognosis of HCC remains dismal. Affymetrix SNP 6.0 array were used to evaluate the genetic characteristics of tumor DNA in 30 HBV-related HCC patients who were underwent liver transplantation. Recurrence related SNPs were selected and validated. Affymetrix SNP 6.0 arrays were performed according to the manufacturer's directions on DNA extracted from formalin-fixed paraffin-embedded HCC tissues
Project description:In the study of tumor genetics, formalin-fixed paraffin-embedded (FFPE) tumors are the most readily available tissue samples. While DNA derived from FFPE tissue has been validated for array comparative genomic hybridization (aCGH) application, the suitability of such fragmented DNA for single-nucleotide polymorphism (SNP) array analysis has not been well examined. Furthermore, whole-genome amplification (WGA) has been used in the study of small precursor lesions to produce sufficient amount of DNA for aCGH analysis. It is unclear whether the same approach can be extended to SNP analysis. In this study, we examined the utility and limitations of genotyping platform performed on whole-genome amplified DNA from FFPE tumor samples for both copy number and SNP analyses. We analyzed the results obtained using DNA derived from matched FFPE and frozen tissue samples on Affymetrix 250K Nsp SNP array. Two widely used WGA methods, Qiagen (isothermal protocol) and Sigma (thermocycling protocol), were used to determine how WGA methods affect the results. We found that the use of DNA derived from FFPE tumors (without or with WGA) for high-resolution SNP array application can produce a significant amount of false positive and false negative findings. While some of these misinterpretations appear to cluster in genomic regions with high or low GC contents, the majority appears to occur randomly. Only large-scale chromosome LOH (>10Mb) can be reliably detected from FFPE tumor DNA samples (without or with WGA) but not smaller LOH or copy number alterations. Our findings here indicate a need for caution in SNP array data interpretation when using FFPE tumor-derived DNA, particularly with WGA. Affymetrix SNP arrays were performed according to the manufacturer's directions on DNA extracted from cryopreserved and FFPE mesenchymal tumor samples without or with WGA, as well as genomic snap-frozen non-neoplastic tissue DNA from 5 adult individuals to serve as reference DNA. WGA was performed using the REPLI-g® FFPE kit (Qiagen, Valencia, CA, USA) and GenomePlex® Tissue Whole Genome Amplification WGA5 kit (Sigma, Saint Louis, MO, USA) in parallel in accordance with the manufacturers’ protocols. A two- to eight-hour individualized reaction time was used in the Qiagen platform for each sample. A gradient amount of initial DNA (10ng, 30ng, 60ng, 100ng and 150ng) was tested followed by gel electrophoresis and qualitative multiplex PCR assay to determine the quality of post-WGA products. At least four independent experiments were concurrently performed per template amplification. Four separateWGA reaction products were pooled for each sample for subsequent microarray analysis to minimize the amplification bias and allele dropout. One of the Affymetrix GeneChip® Human Mapping 500K Array Set (Nsp 250K SNP array) was used for genotyping analysis. Four gastrointestinal stromal tumors with known cytogenetic aberrations were included. Two cases were sucessfullly amplified and passed the quality tests. A total of 12 samples were compared between each other, including frozen tissue DNA (as reference), frozen tissue DNA with WGA (two platforms), FFPE tissue DNA, and FFPE tissue DNA with WGA (two platforms) from each case.
Project description:The development of oral squamous cell carcinoma (OSCC) is a multistep process requiring the accumulation of genetic alterations. To identify genes responsible for OSCC development, we performed high-density single-nucleotide polymorphism array analysis and genome-wide gene expression profiling on OSCC tumors. These analyses identified "absent in melanoma (AIM2)" and "interferon-inducible gene 16 (IFI16)," mapped to the hematopoietic IFN-inducible nuclear proteins with 200-amino acid repeat (HIN-200) gene cluster in the amplified region of chromosome 1q23, with overexpression in OSCCs. AIM2 and IFI16 are cytoplasmic double-stranded DNA sensors for innate immunity and act as tumor suppressors in several human cancers. Knockdown of AIM2 or IFI16 in OSCC cells resulted in the suppression of cell growth and the induction of apoptosis, accompanied by the downregulation of NF-κB activation. Because all of the OSCC cell lines had impairment of p53 activity, wild-type p53 was introduced in p53-deficient OSCC cells, and as a result, the expression of wild-type p53 suppressed cell growth and induced apoptosis via suppression of NF-κB activity. Finally, the coexpression of AIM2 and IFI16 significantly enhanced cell growth in p53-deficient cells; in contrast, the expression of AIM2 and/or IFI16 in cells bearing wild-type p53 suppressed cell growth. Moreover, AIM2 and IFI16 synergistically enhanced NF-κB signaling in p53-deficient cells. Thus, expression of AIM2 and IFI16 may have oncogenic functions in OSCC cells inactivating p53 system. Copy number analysis of Affymetrix 250K SNP arrays was performed for 5 oral leukoplakia samples, 20 oral squamous cell carcinoma samples, and 8 oral squamous cell carcinoma cell lines.
Project description:Affymetrix SNP arrays were performed according to the manufacturer's directions on DNA extracted from fresh frozen tissues. To obtain a profile of copy number alterations in RMS, we studied 65 samples in 60 RMS cases. Other data of 38 samples are deposited in GSE41263: GSM1528059 GSM1528057 GSM1528061 GSM1528058 GSM1528054 GSM1528060 GSM1012723 GSM1012722 GSM1012746 GSM1528055 GSM1528056 GSM1530028 GSM1012751 GSM1012724 GSM1012726 GSM1012747 GSM1012725 GSM1012716 GSM1012735 GSM1012713 GSM1012736 GSM1012737 GSM1012738 GSM1012730 GSM1012739 GSM1012740 GSM1012750 GSM1012717 GSM1012718 GSM1012719 GSM1012741 GSM1012732 GSM1012715 GSM1012720 GSM1012742 GSM1012721 GSM1012743 GSM1012744 Copy number analysis of Affymetrix 250K or Cytoscan_HD SNP arrays was performed for 27 rhabdomyosarcoma samples.
Project description:Methods for haplotyping and DNA copy number typing of single cells are paramount for studying genomic heterogeneity and enabling genetic diagnosis. Before analyzing the DNA of a single cell by microarray or next-generation sequencing, a whole-genome amplification (WGA) process is required that substantially distorts the frequency and composition of the cell’s alleles. As a consequence, haplotyping methods suffer from error-prone discrete SNP-genotypes (AA, AB, BB), and DNA copy number profiling remains difficult as true DNA copy number aberrations have to be discriminated from WGA-artifacts. Here, we developed a single-cell genome analysis method that reconstructs genome-wide haplotype architectures as well as the copy-number and segregational origin of those haplotypes by deciphering WGA-distorted SNP B-allele fractions, using a process we coin haplarithmisis. We demonstrate clinical precision of the method on single cells biopsied from human embryos to diagnose disease alleles genome wide, we advance and facilitate the detection of numerical and structural chromosomal anomalies in single cells, and can distinguish meiotic from mitotic segregation errors in a single assay. The samples of a reference family were applied for optimisation of single-cell genotyping using Affymetrix SNP-arrays prior to downstream analysis. Specifically, the reference family delivers genomic DNA samples isolated from peripheral blood of two siblings 'S1' and 'S2', the mother and father of these siblings, as well as of the maternal grandmother and grandfather. Of individuals ‘S1’ and ‘S2’, six EBV-transformed lymphoblastoid single cells were isolated of which three were whole-genome amplified using MDA and three using PicoPlex. These WGA-products were hybridized to Affymetrix NspI 250K SNP-arrays following the protocol as recommended by the company. Subsequently, the SNP-probe signals were interpreted by different genotyping algorithms (see data processing). Based on overall performance, it was decided to use the Dynamic Model (DM) for interpreting Affymetrix SNP-probe signals of single cells.
Project description:Technologies based on DNA microarrays have the potential to provide detailed information on genomic aberrations in tumor cells. In practice a major obstacle for quantitative detection of aberrations is the heterogeneity of clinical tumor tissue. Tumor tissue consists of a mixture of tumor cells and normal cells, including inflammatory and stromal cells, which may lead to a failure to detect aberrations in the tumor cells. Principal finding: Using SNP array data from 43 non-small cell lung cancer samples we have developed a bioinformatic algorithm that accurately models the fractions of normal and tumor cells in clinical tumor samples. The proportion of normal cells and SNP array data can be used to detect and quantify copy number neutral loss-of-heterozygosity (CNNLOH) in the tumor cells both in crude tumor tissue and in samples enriched for tumor cells by laser capture microdissection. Conclusion: Genome-wide quantitative analysis of CNNLOH using the CNNLOH Quantifier method can help to identify recurrent aberrations contributing to tumor development in clinical tumor samples. In addition, SNP-array based analysis of CNNLOH may become important for detection of aberrations that can be used for diagnostic and prognostic purposes, as well as to predict response to therapy.
Project description:Genome-Wide Screening of Genomic Alterations and Transcriptional Modulation in Non-Smoking Female Lung Cancer in Taiwan Sixty-one pairs of cancer and normal lung tissue specimens from non-smoking females were collected at National Taiwan University Hospital and Taichung Veterans General Hospital. The selection criteria of clinical specimens depend on pathology report, physical examination and cigarette-smoking history. Surgical lung tissue specimens were immediately snap-frozen in liquid N2 and stored at -80 °C. Surgical specimens would be further processed for RNA and DNA extraction. Only those samples passed quality controls were processed for gene expression profiling analysis and single nucleotide polymorphism (SNP) analysis respectively.
Project description:Genomic copy-number changes were measured using 250K StyI SNP arrays after selection of cells to enrich for resistance to BEZ235. Affymetrix SNP arrays were performed according to the manufacturer's directions on DNA extracted using Qiagen DNeasy from engineered human cell-lines. Resulting alterations in copy numbers were calculated based on SNP intensities.