Unknown,Transcriptomics,Genomics,Proteomics

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Immunomagnetic enrichment and flow cytometric isolation of breast cancer circulating tumor cells (CTCs) for genomic characterization

ABSTRACT: We developed a novel approach to isolate tumor cells with high purity from blood via immunomagnetic enrichment followed by fluorescence activated cell sorting (IE/FACS) and examined copy number alterations in these cells. Magnetic beads coated with EpCAM mAb were added to blood to enrich for tumor cells. Enriched samples were then subjected to FACS analysis using differentially labeled mAbs to distinguish tumor cells (EpCAM+) from leukocytes (CD45+) during sorting. DNA from isolated tumor cells was subjected to whole genome amplification (WGA) and copy number analysis via array comparative genomic hybridization (CGH). The assay was evaluated using BT474 and MCF7 breast cancer cell lines and in CTCs from 5 metastatic breast cancer (MBC) patients with matched archival primary tumors and later extended to an additional 97 MBC patients. Evaluation of the assay on isolated breast cancer cell lines spiked into blood correctly identified the known genomic alterations with high reproducibility. In clinical studies, comparison of CTCs with matched archival primary tumors confirmed shared lineage with notable divergence. In addition, serial testing of CTCs confirmed reproducibility, and indicated genomic change over time. Analysis of genomic profiles of CTCs from 102 MBC patients revealed common copy number alterations including gains in 1q and 8q and losses in 8p and 11q. Comparison with a published CGH dataset of primary breast tumors revealed similar frequencies of recurrent genomic copy number aberrations.

ORGANISM(S): Homo sapiens

SUBMITTER: Mark Magbanua

PROVIDER: E-GEOD-27511 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:About 230 clinical trials currently explore the role of circulating tumor cell (CTC) analysis for therapy decisions, but no assays enable comprehensive molecular characterization of CTCs with diagnostic precision. We therefore combined a workflow for CTC enrichment and isolation with 100% purity with a non-random whole genome amplifiation method for single cells and applied it to 510 single CTCs and 189 leukocytes of 66 breast cancer patients. We defined a genome integrity index (GII) to identify cells suited for molecular chracterization by different molecular assay in more than 90% of single cells, such as diagnostic profiling for point mutations, gene amplifications and whole genomes of single cells. The high reliability on clinical samples enabled assessing the molecular heterogeneity of single CTCs of metastatic breast cancer patients. We readily identified therapeutically relevant genomic disparity between primary tumors and CTCs. Microheterogeneity analysis among individual CTCs uncovered preexisting cells reistsant to ERBB2 targeted therapies suggesting ongoing microevolution at late stage disease whose exploration may provide essential information for personalized treatment decisions. The analysis aimed to indentify profiles of copy number changes in genomic DNA of single circulating tumor cells (CTCs). For this, CTCs were enrched using the FDA approved CellSearch System and single-cell were isolated using the DEPArray System. Subsequently, single-cell DNA was amplified using the Ampli1 WGA Kits and subjected to single-cell aCGH analysis according to previously published protocol (Czyz ZT et al., PLoS One. 2014 Jan 21;9(1):e85907). The analysis included 38 single CTCs and 10 white blood cells (WBCs) obtained from 16 breast cancer patient. WBCs were used as controls for the analysis. In addition, four CTC cell pools were included in the analysis. This was done to show the discrepancies between the profiles of individual cells and corresponing average genomic profile of CTCs in a patient material (cell pools), thereby demonstrating the importance of the analysis on the cell-by-cell basis. The reference sample used for all aCGH experiments consisted of a pool of four single-cell WGA products generated from WBCs of a healthy female donor.

Project description:Metastasis is responsible for the vast majority of breast cancer related deaths. Metastatic breast cancer (MBC) is inherently different than primary breast cancer (BC), evolving under selection pressure at different organ sites or during systemic therapy. The current ASCO guidelines call for biopsy of a metastatic site to guide decision making for systemic therapy. Yet, biopsies of macro metastasis are oftentimes not feasible in the clinical setting. Circulating tumor cells (CTCs) have been shown to be prognostic in MBC, but their use as clinical biomarker beyond CTC enumeration has been limited. A better understanding of CTC-biology compared to metastasis may shed light on treatment opportunities and help advance the application of CTCs as liquid biopsies in clinical practice. The ANGLE Parsortix system is a microfluidics device that separates CTCs based on size and deformability, without the need for cell-surface marker selection. Our lab has previously demonstrated the feasibility of gene expression profiling of rare CTCs. Here, we evaluated whether whole transcriptome sequencing (RNA Seq) gene expression profiling of ANGLE Parsortix isolated CTCs may serve as a surrogate for biopsies of macro metastases. CTCs from 21 MBC patients were enumerated and captured from 10mL peripheral blood (PB) via the ANGLE Parsortix system. RNA Seq was performed on fresh metastatic tumor biopsies (mets), CTCs and peripheral blood from all patients. Biopsy sites included: skin (n=1), lung (n=1), pleural effusion (n=5), pericardial effusion (n=1), breast (n=3), lymph node (n=2), brain (n=4), liver (n=1), ascites (n=3), cerebrospinal fluid (n=2) and bone (n=1). 19/21 patients were included in subsequent data analysis. We present the whole transcriptomic landscape of CTCs with comparison to metastases and peripheral blood all acquired prior to treatment of Stage IV breast cancer. Multiple genes, including oncogenes, breast epithelial, mesenchymal genes and cancer stem cell genes were found with higher expression in CTCs versus metastases. When focusing on 66 known potentially clinically actionable genes in breast cancer, represented by 7 molecular signaling pathways, CTCs did not show significantly different patterns of expression versus mets compared to PB. RNA Seq of CTCs may be utilized to identify alterations in MBC patients that are potentially clinically actionable.

Project description:The aim of this study was to establish a single-cell array comparative genomic hybridization (SCaCGH) method providing in-depth genomic analysis of circulating tumor cells (CTCs) and disseminated tumor cells (DTCs). The robustness and resolution limits of the method were estimated with different cell amounts of the breast cancer cell line SKBR3 using 44k and 244k arrays. Subsequent adjustments of the method were conducted analyzing the copy number profiles of 28 CTCs in combination with four hematopoietic cell (HC) controls from eight metastatic patients and of 24 DTCs, three probable HCs, and five HC controls from seven breast cancer patients and one healthy donor. The frequency of the major genomic gains and losses of the analyzed DTC revealed similarities to primary breast tumor samples with some evident differences. Three of the patients had available profiles for DTC and the corresponding primary tumor. In 2/3 of the examined DTCs, equivalent genomic changes and common aberration breakpoints were disclosed, both to each other and to the corresponding primary tumors. Interestingly, similar copy number changes were found in DTCs taken at time of diagnosis or in DTCs collected at 3-years relapse-free follow up. Residual immunomorphological characterized tumor cells showed balanced profiles with only minor aberrations. Three cells with unclear morphological identification showed either balanced profiles (n=2) or aberrations comparable to the primary tumor and DTC (n=1). SCaCGH may be a powerful tool for molecular characterisation of immunostained and morphological identified CTCs and DTCs to explore the malignant potential, therapeutic targets and tumor heterogeneity of single tumor cells. 24 DTCs, 3 probable HCs, and 5 HCs from 7 early-stage breast cancer patients, 28 CTCs and 4 HCs from 8 metastatic breast cancer patients, and 1 healthy donor were analysed. Comparison with the primary tumor was done in 3 patients. The reference for the patients was DNA from multiple anonymous female donors. This submission does not include the SKBR3 data obtained from the 44k array.

Project description:Circulating tumor cells (CTCs) are critical in the development of distant organ tumor metastasis, and are associated with advanced cancer stage and poor patient outcome. Here, we present the first genome-wide nucleotide-level characterization of CTCs. Our single-nucleotide polymorphism (SNP) analysis in patients with melanoma involved: 1) global comparative genomic analysis of CTCs and matched regional metastases, 2) identification of key genomic aberrations in CTCs, 3) verification of these target genes in aggressive distant tumor metastases, and 4) evidence of selective expression and functional consequence of CTC-associated genes in melanomas. We report 131 aberrant loci in CTCs that are potentially pro-metastatic, and show that such expression of a 5-marker gene panel (CSMD2, CNTNAP5, FLJ14051, ADAM6, TRPM2) in melanomas confers prognostic utility. Successful treatment of melanoma requires understanding of the metastatic process and identification of patients with tumors most likely to develop aggressive metastatic disease. Melanomas are heterogeneous, and CTCs have long been recognized as vehicles for cancer spread, representing particularly aggressive tumor clones that can evolve into successful clinical metastases. Elucidation of genomic aberrations in CTCs will aid in the development of prognostic biomarkers and therapeutic strategies to target CTCs to prevent or control distant cancer spread. This study provides the first detailed genomic confirmation of the close relation between CTCs and tumor metastases, and illustrates how CTCs can be utilized as a novel approach and rational source for identification of pro-metastatic genes in cancer research. Three individual patient cohorts were utilized in the study. CNV and LOH loci were evaluated initially in metastatic melanoma patients (n=13) in a discovery cohort. SNP loci that harbored CNV/LOH in CTCs were then separately verified for: (a) presence in distant organ metastasis (AJCC Stage IV melanoma) (n=27), and (b) relevance to prognosis in regional melanoma metastasis (AJCC Stage III melanoma) (n=35). The first discovery patient cohort group was utilized for capture of CTCs, and consisted of peripheral blood mononuclear cell (PBMC) and tumor specimens from metastatic melanoma patients (n=13). CTC-related loci were verified in a second cohort of patients with Stage IV distant organ metastases (n=27), including 15 brain, 4 lung, and 8 gastrointestinal (bowel, liver) metastases. The third patient cohort consisted of early passage (<12) established melanoma cell lines derived from 35 regional melanoma metastases (Stage III) for evaluation of the prognostic utility of the CTC-associated aberrant loci.

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Immunomagnetic enrichment and flow cytometric isolation of breast cancer circulating tumor cells (CTCs) for genomic characterization

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