Name: adaptation of semiautomated circulating tumor cell (ctc) assays for clinical and preclinical research applications
Uploaded: 2014-02-28T14:45:00
Description: Watch this Scientific Journal Video about Adaptation of Semiautomated Circulating Tumor Cell CTC Assays for Clinical and Preclinical Research Applications at JoVE.com

This work was supported by grants from the Ontario Institute of Cancer Research (#08NOV230), the Canada Foundation for Innovation (#13199), Prostate Cancer Canada, Janssen Oncology, the London Regional Cancer Program, and donor support from John and Donna Bristol through the London Health Sciences Foundation (to A.L.A.). L.E.L. is supported by a Frederick Banting and Charles Best Canada Graduate Scholarship Doctoral Award. A.L.A is supported by a CIHR New Investigator Award and an Early Researcher Award from the Ontario Ministry of Research and Innovation.

All human studies described in this manuscript were carried out under protocols approved by Western University&#39;s Human Research Ethics Board. All Animal studies were conducted in accordance with the recommendations of the Canadian Council on Animal Care, under protocols approved by the Western University Animal Use Subcommittee.
1. Standard CTC Enumeration from Patient Blood Samples Using the CSS
1. Human Blood Sample Collection and Preparation for Processing on the ...

<ol>
	<li>Siegel, R., Naishadham, D., Jemal, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cancer+statistics.">Cancer statistics.</a> 63 (1), 11-30 (2013).</li><li>Chambers, A. F., Groom, A. C., MacDonald, I. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dissemination+and+growth+of+cancer+cells+in+metastatic+sites.">Dissemination and growth of cancer cells in metastatic sites.</a> Nat. Rev. Cancer. 2 (8), 563-572 (2002).</li><li>Pantel, K., Brakenhoff, R. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dissecting+the+metastatic+cascade.">Dissecting the metastatic cascade.</a> Nat. Rev. Cancer. 4 (6), 448-456 (2004).</li><li>Cristofanilli, M., Budd, G. T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Circulating+tumor+cells,+disease+progression,+and+survival+in+metastatic+breast+cancer.">Circulating tumor cells, disease progression, and survival in metastatic breast cancer.</a> New Engl. J. Med. 351 (8), 781-791 (2004).</li><li>De Bono, J. S., Scher, H. I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Circulating+tumor+cells+predict+survival+benefit+from+treatment+in+metastatic+castration-resistant+prostate+cancer.">Circulating tumor cells predict survival benefit from treatment in metastatic castration-resistant prostate cancer.</a> Clin. Cancer Res. 14 (19), 6302-6309 (2008).</li><li>Cohen, S. J., Ja Punt, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prognostic+significance+of+circulating+tumor+cells+in+patients+with+metastatic+colorectal+cancer.">Prognostic significance of circulating tumor cells in patients with metastatic colorectal cancer.</a> Ann. Oncol. 20 (7), 1223-1229 (2009).</li><li>Hayes, D. F., Cristofanilli, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Circulating+tumor+cells+at+each+follow-up+time+point+during+therapy+of+metastatic+breast+cancer+patients+predict+progression-free+and+overall+survival.">Circulating tumor cells at each follow-up time point during therapy of metastatic breast cancer patients predict progression-free and overall survival.</a> Clin. Cancer Res. 12 (14), 4218-4224 (2006).</li><li>Budd, G. T., Cristofanilli, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Circulating+tumor+cells+versus+imaging--predicting+overall+survival+in+metastatic+breast+cancer.">Circulating tumor cells versus imaging--predicting overall survival in metastatic breast cancer.</a> Clin. Cancer Res. 12 (21), 6403-6409 (2006).</li><li>Olmos, D., Arkenau, H. -. T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Circulating+tumour+cell+(CTC)+counts+as+intermediate+end+points+in+castration-resistant+prostate+cancer+(CRPC):+a+single-centre+experience.">Circulating tumour cell (CTC) counts as intermediate end points in castration-resistant prostate cancer (CRPC): a single-centre experience.</a> Ann. Oncol. 20 (1), 27-33 (2009).</li><li>De Bono, J. S., Scher, H. I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Circulating+tumor+cells+predict+survival+benefit+from+treatment+in+metastatic+castration-resistant+prostate+cancer.">Circulating tumor cells predict survival benefit from treatment in metastatic castration-resistant prostate cancer.</a> Clin. Cancer Res. 14 (19), 6302-6309 (2008).</li><li>Allan, A. L., Keeney, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Circulating+tumor+cell+analysis:+technical+and+statistical+considerations+for+application+to+the+clinic.">Circulating tumor cell analysis: technical and statistical considerations for application to the clinic.</a> J. Oncol. 2010, 426218 (2010).</li><li>Lowes, L. E., Goodale, D., Keeney, M., Allan, A. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Image+cytometry+analysis+of+circulating+tumor+cells.">Image cytometry analysis of circulating tumor cells.</a> Methods Cell Biol. 102, 261-290 (2011).</li><li>Lianidou, E. S., Markou, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Circulating+tumor+cells+in+breast+cancer:+detection+systems,+molecular+characterization,+and+future+challenges.">Circulating tumor cells in breast cancer: detection systems, molecular characterization, and future challenges.</a> Clin. Chem. 57 (9), 1242-1255 (2011).</li><li>Alix-Panabi&#232;res, C., Pantel, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Circulating+tumor+cells:+liquid+biopsy+of+cancer.">Circulating tumor cells: liquid biopsy of cancer.</a> Clin. Chem. 59 (1), 110-118 (2013).</li><li>Parkinson, D. R., Dracopoli, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Considerations+in+the+development+of+circulating+tumor+cell+technology+for+clinical+use.">Considerations in the development of circulating tumor cell technology for clinical use.</a> J. Transl. Med. 10, 138 (2012).</li><li>Lowes, L. E., Hedley, B. D., Keeney, M., Allan, A. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=User-defined+protein+marker+assay+development+for+characterization+of+circulating+tumor+cells+using+the+CellSearch+system.">User-defined protein marker assay development for characterization of circulating tumor cells using the CellSearch system.</a> Cytomet. A. 81 (11), 983-995 (2012).</li><li>Fehm, T., M&#252;ller, V., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=HER2+status+of+circulating+tumor+cells+in+patients+with+metastatic+breast+cancer:+a+prospective,+multicenter+trial.">HER2 status of circulating tumor cells in patients with metastatic breast cancer: a prospective, multicenter trial.</a> Breast Cancer Res. Treat. 124 (2), 403-412 (2010).</li><li>Liu, Y., Liu, Q., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Circulating+tumor+cells+in+HER2-positive+metastatic+breast+cancer+patients:+a+valuable+prognostic+and+predictive+biomarker.">Circulating tumor cells in HER2-positive metastatic breast cancer patients: a valuable prognostic and predictive biomarker.</a> BMC Cancer. 13, 202 (2013).</li><li>Slamon, D. J., Leyland-Jones, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+chemotherapy+plus+a+monoclonal+antibody+against+HER2+for+metastatic+breast+cancer+that+overexpresses+HER2.">Use of chemotherapy plus a monoclonal antibody against HER2 for metastatic breast cancer that overexpresses HER2.</a> New Engl. J. Med. 344 (11), 783-792 (2001).</li><li>Marty, M., Cognetti, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Randomized+phase+II+trial+of+the+efficacy+and+safety+of+trastuzumab+combined+with+docetaxel+in+patients+with+human+epidermal+growth+factor+receptor+2-positive+metastatic+breast+cancer+administered+as+first-line+treatment:+the+M77001+study+group.">Randomized phase II trial of the efficacy and safety of trastuzumab combined with docetaxel in patients with human epidermal growth factor receptor 2-positive metastatic breast cancer administered as first-line treatment: the M77001 study group.</a> J. Clin. Oncol. 23 (19), 4265-4274 (2005).</li><li>Slamon, D., Eiermann, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adjuvant+trastuzumab+in+HER2-positive+breast+cancer.">Adjuvant trastuzumab in HER2-positive breast cancer.</a> New Engl. J. Med. 365 (14), 1273-1283 (2011).</li><li>Welch, D. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Technical+considerations+for+studying+cancer+metastasis+in+vivo.">Technical considerations for studying cancer metastasis in vivo.</a> Clin. Exp. Metast. 15 (3), 272-306 (1997).</li><li>Goodale, D., Phay, C., Postenka, C. O., Keeney, M., Allan, A. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+tumor+cell+dissemination+patterns+in+preclinical+models+of+cancer+metastasis+using+flow+cytometry+and+laser+scanning+cytometry.">Characterization of tumor cell dissemination patterns in preclinical models of cancer metastasis using flow cytometry and laser scanning cytometry.</a> Cytometry A. 75 (4), 344-355 (2009).</li><li>Gorges, T. M., Tinhofer, I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Circulating+tumour+cells+escape+from+EpCAM-based+detection+due+to+epithelial-to-mesenchymal+transition.">Circulating tumour cells escape from EpCAM-based detection due to epithelial-to-mesenchymal transition.</a> BMC Cancer. 12, 178 (2012).</li><li>Eliane, J. -. P., Repollet, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Monitoring+serial+changes+in+circulating+human+breast+cancer+cells+in+murine+xenograft+models.">Monitoring serial changes in circulating human breast cancer cells in murine xenograft models.</a> Cancer Res. 68 (14), 5529-5532 (2008).</li><li>Flores, L. M., Kindelberger, D. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improving+the+yield+of+circulating+tumour+cells+facilitates+molecular+characterisation+and+recognition+of+discordant+HER2+amplification+in+breast.">Improving the yield of circulating tumour cells facilitates molecular characterisation and recognition of discordant HER2 amplification in breast.</a> 102 (10), 1495-1502 (2010).</li><li>Sieuwerts, A. M., Kraan, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+characterization+of+circulating+tumor+cells+in+large+quantities+of+contaminating+leukocytes+by+a+multiplex+real-time+PCR.">Molecular characterization of circulating tumor cells in large quantities of contaminating leukocytes by a multiplex real-time PCR.</a> Breast Cancer Res. Treat. 118 (3), 455-468 (2009).</li><li>Cohen, S. J., Ja Punt, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Relationship+of+circulating+tumor+cells+to+tumor+response,+progression-free+survival,+and+overall+survival+in+patients+with+metastatic+colorectal+cancer.">Relationship of circulating tumor cells to tumor response, progression-free survival, and overall survival in patients with metastatic colorectal cancer.</a> J. Clin. Oncol. 26 (19), 3213-3221 (2008).</li><li>Allard, W. J., Matera, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tumor+cells+circulate+in+the+peripheral+blood+of+all+major+carcinomas+but+not+in+healthy+subjects+or+patients+with+nonmalignant+diseases.">Tumor cells circulate in the peripheral blood of all major carcinomas but not in healthy subjects or patients with nonmalignant diseases.</a> Clin. Cancer Res. 10 (20), 6897-6904 (2004).</li><li>Thiery, J. P., Acloque, H., Huang, R. Y. J., Nieto, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Epithelial-mesenchymal+transitions+in+development+and+disease.">Epithelial-mesenchymal transitions in development and disease.</a> Cell. 139 (5), 871-890 (2009).</li><li>Yang, J., Weinberg, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Epithelial-mesenchymal+transition:+at+the+crossroads+of+development+and+tumor+metastasis.">A Epithelial-mesenchymal transition: at the crossroads of development and tumor metastasis.</a> Dev. Cell. 14 (6), 818-829 (2008).</li><li>Gradilone, A., Raimondi, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Circulating+tumour+cells+lacking+cytokeratin+in+breast+cancer:+the+importance+of+being+mesenchymal.">Circulating tumour cells lacking cytokeratin in breast cancer: the importance of being mesenchymal.</a> J. Cell. Mol. Med. 15 (5), 1066-1070 (2011).</li><li>K&#246;nigsberg, R., Obermayr, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Detection+of+EpCAM+positive+and+negative+circulating+tumor+cells+in+metastatic+breast+cancer+patients.">Detection of EpCAM positive and negative circulating tumor cells in metastatic breast cancer patients.</a> Acta Oncol. 50 (5), 700-710 (2011).</li><li>Kasimir-Bauer, S., Hoffmann, O., Wallwiener, D., Kimmig, R., Fehm, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Expression+of+stem+cell+and+epithelial-mesenchymal+transition+markers+in+primary+breast+cancer+patients+with+circulating+tumor+cells.">Expression of stem cell and epithelial-mesenchymal transition markers in primary breast cancer patients with circulating tumor cells.</a> Breast Cancer Res. 14 (1), (2012).</li><li>Mego, M., Mani, S. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Expression+of+epithelial-mesenchymal+transition-inducing+transcription+factors+in+primary+breast+cancer:+The+effect+of+neoadjuvant+therapy.">Expression of epithelial-mesenchymal transition-inducing transcription factors in primary breast cancer: The effect of neoadjuvant therapy.</a> Int. J. Cancer. 130 (4), 808-816 (2012).</li><li>Yu, M., Bardia, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Circulating+breast+tumor+cells+exhibit+dynamic+changes+in+epithelial+and+mesenchymal+composition.">Circulating breast tumor cells exhibit dynamic changes in epithelial and mesenchymal composition.</a> Science. 339 (6119), 580-584 (2013).</li><li>Armstrong, A. J., Marengo, M. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Circulating+tumor+cells+from+patients+with+advanced+prostate+and+breast+cancer+display+both+epithelial+and+mesenchymal+markers.">Circulating tumor cells from patients with advanced prostate and breast cancer display both epithelial and mesenchymal markers.</a> Mol. Cancer Res. 9 (8), 997-1007 (2011).</li></ol>

Despite the development of many new CTC technologies since the introduction of the CSS in 2004, this technique is still the only clinically approved technology on the market today and therefore it is considered the current gold standard for CTC detection and enumeration. This manuscript has demonstrated that although the CSS has rigorous quality control standards it can be subject to interpretation bias and that CTC identification in patient samples is much different from identification in spiked samples. Six categories ...

In 2013 it is estimated that 580,350 individuals will die from cancer and that 1,660,290 new cases of this disease will be diagnosed in the United States alone1. The majority of these deaths occur subsequent to the development of metastatic disease2. The current lack of effective therapies in treating metastases and a limited understanding of the metastatic cascade makes this stage of disease highly lethal. The presence of circulating tumor cells (CTCs) within the bloodstream have been demonstrated to correlate with metastatic disease3. These cells are extremely rare and their detection is indicative of overall survival in metastatic breast4, prostate5, and colorectal6 cancer. In these patients, the presence of &#8805;5 (breast and prostate) or &#8805;3 (colorectal) CTCs in 7.5 ml of blood is indicative of poorer prognosis when compared to those patients with fewer or no detectable CTCs in the same blood volume. In addition, the change in CTC number during or after therapeutic intervention has been demonstrated to be useful as a predictor of treatment response, often sooner than currently utilized techniques7-10.
It has been estimated that, in metastatic cancer patients, CTCs occur at a frequency of approximately 1 CTC per 105-107 blood mononuclear cells and in patients with localized disease, this frequency may be even lower (~1 in 108). The rare nature of these cells can make it difficult to accurately and reliably detect and analyze CTCs11. Several methods (reviewed previously12-14) have been utilized to enrich and detect these cells by exploiting properties that differentiate them from surrounding blood components. In general, CTC enumeration is a two-part process that requires both an enrichment step and a detection step. Traditionally, enrichment steps rely on differences in physical properties of CTCs (cell size, density, deformability) or on protein marker expression (i.e. epithelial cell adhesion molecule [EpCAM], cytokeratin [CK]). Following enrichment, CTC detection can be performed in a number of different ways, the most common of which are nucleic acid-based assays and/or cytometric approaches. Each of these strategies are unique, having distinct advantages and disadvantages, however they all lack standardization; a necessity for entrance into the clinical setting. The CellSearch system (CSS) was therefore developed to provide a standardized method for the detection and enumeration of rare CTCs in human blood using fluorescence microscopy and antibody-based techniques4-6. This platform is currently considered the gold standard in CTC enumeration and is the only technique approved by the U.S. Food and Drug Administration (FDA) for use in the clinic15.
The CSS is a two component platform consisting of, (1) the CellTracks AutoPrep system (hereafter referred to as the preparation instrument), which automates the preparation of human blood samples, and (2) the CellTracks Analyzer II (hereafter referred to as the analysis instrument), which scans these samples following preparation. To distinguish CTCs from contaminating leukocytes the preparation instrument employs an antibody mediated, ferrofluid-based magnetic separation approach and differential fluorescence staining. Initially, the system labels CTCs using anti-EpCAM antibodies conjugated to iron nanoparticles. The sample is then incubated in a magnetic field, and all unlabeled cells are aspirated. Selected tumor cells are resuspended, and incubated in a differential fluorescence stain, consisting of fluorescently-labeled antibodies and a nuclear staining reagent. Finally, the sample is transferred to a magnetic cartridge, called a MagNest (hereafter referred to as the magnetic device), and scanned using the analysis instrument.
The analysis instrument is used to scan prepared samples using different fluorescence filters, each optimized to the appropriate fluorescent particle, using a 10X objective lens. CTCs are identified as cells that are bound by anti-EpCAM, anti-pan-CK-phycoerythrin (PE) (CK8, 18, and 19), and the nuclear stain 4&#39;,6-diamidino-2-phenylindole (DAPI). Conversely, contaminating leukocytes are identified as cells that are bound by anti-CD45-allophycocyanin (APC) and DAPI. Following scanning, computer-defined potential tumor cells are presented to the user. From these images, the user must employ qualitative analysis using the defined parameters and differential staining discussed above to determine which events are CTCs.
In addition to providing a standardized method for CTC enumeration, the CSS allows for molecular characterization of CTCs based on protein markers of interest. This interrogation can be performed at the single-cell level, using a fluorescein isothiocyanate (FITC) fluorescence channel not required for CTC identification16. Although this platform provides the capacity for molecular characterization, the detailed process of protocol development and optimization is not well-defined. Three commercially available markers have been developed by the manufacturer for use with the CSS, including epidermal growth factor receptor (EGFR), human epidermal growth factor receptor 2 (HER2), and insulin-like growth factor 1 receptor (IGF-1R). HER2 analysis, in combination with the CSS, has been utilized by several groups to illustrate the potential for CTC characterization to inform clinical decision-making and to potentially change existing treatment guidelines. For example, Fehm et al.17&#160;demonstrated that approximately one third of breast cancer patients with HER2-primary tumors had HER2+ CTCs. In addition, Liu et al.18&#160;recently reported that up to 50% of patients with HER+ metastatic breast cancer did not have HER2+ CTCs. Herceptin, a HER2 receptor interfering monoclonal antibody demonstrated to greatly benefit patients whose tumors express sufficient levels of HER2, is a commonly utilized treatment for patients with HER2+ primary tumors19-21. However, these studies suggest that Herceptin may be being sub-optimally utilized and that CTC characterization may aid in predicting treatment response. Ultimately, CTC characterization may have the potential to improve personalized care.
CTC research is unique in that it has largely utilized a bedside-to-benchtop approach. This method, unlike benchtop-to-bedside research, which can often take years to impact patient care, has allowed CTCs quick entry into the clinical setting. However, physicians are hesitant to use results from CTC analysis in patient treatment decision-making due to a lack of understanding of their underlying biology. Therefore appropriate preclinical mouse models of metastasis and complementary CTC analysis techniques must be utilized in order to investigate these outstanding questions. In general, there are two&#160;types of preclinical models used to study the metastatic cascade, (1) spontaneous metastasis models, which allow for the study of all the steps in the metastatic cascade, and (2) experimental metastasis models, which only allow for the study of later steps in the metastatic process such as extravasation and secondary tumor formation22. Spontaneous metastasis models, involve tumor cell injections into appropriate orthotopic locations (e.g. injection of prostate cancer cells into the prostate gland for the study of prostate cancer). Cells are then given time to form primary tumors and spontaneously metastasize to secondary sites such as the bone, lung, and lymph nodes. In contrast, experimental metastasis models involve direct injection of tumor cells into the bloodstream (e.g. via tail vein or intracardiac injection to target cells to specific locations) and therefore skip the initial steps of intravasation and dissemination to secondary organs22. Thus far the majority of CTC analysis in in vivo model systems has been performed using either cytometry-based23 or adapted human-based CTC techniques (e.g. AdnaTest)24. Although useful, none of these techniques adequately reflect CTC enumeration using the gold standard CSS. Based on the clinical approval, standardized nature, and widespread usage of the CSS, the development of a CTC capture and detection technique for in vivo modeling that utilizes equivalent sample preparation, processing, and identification criteria would be advantageous as results would be comparable to those obtained from patient samples. However, due to the volume requirements of the preparation instrument it is not possible to process small volumes of blood using this automated platform. In addition, previous work by Eliane et al.25&#160;has demonstrated that contamination of samples with mouse epithelial cells (which also meet the standard CTC definition [EpCAM+CK+DAPI+CD45-]) can lead to misclassification of mouse squamous epithelial cells as CTCs. To address these issues an adapted technique that allows the utilization of the CSS CTC kit reagents combined with a manual isolation procedure was developed. The addition of a FITC labeled human leukocyte antigen (HLA) antibody to the assay allows human tumor cells to be distinguished from mouse squamous epithelial cells.
This manuscript describes the standard, commercially developed and optimized CSS protocol for processing patient blood samples and common pitfalls that may be encountered, including discrepant items that can lead to CTC misclassification errors. In addition, customization of the CSS assay to examine user-defined protein characteristics of captured CTCs and a comparable adapted CSS technique that allows for the enrichment and detection of CTCs from small volumes of blood in preclinical mouse models of metastasis are described.

<table border="0" cellpadding="0" cellspacing="0" width="790">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:267px;">REAGENTS</td>
			<td style="width:175px;"></td>
			<td style="width:161px;"></td>
			<td style="width:188px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:267px;">0.5M EDTA</td>
			<td style="width:175px;"></td>
			<td style="width:161px;"></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:267px;">Anti-human CD44-FITC</td>
			<td style="width:175px;">BD Pharmigen&#160;</td>
			<td style="width:161px;">555478</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:267px;">Anti-human CD44-PE</td>
			<td style="width:175px;">BD Pharmigen&#160;</td>
			<td style="width:161px;">555479</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:267px;">Anti-human HLA-AlexaFluor488</td>
			<td style="width:175px;">BioLegend</td>
			<td style="width:161px;">311415</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:267px;">Anti-mouse CD45-APC</td>
			<td style="width:175px;">eBioscience</td>
			<td style="width:161px;">17-0451-82</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:267px;">Bond Primary Antibody Diluent</td>
			<td style="width:175px;">Leica</td>
			<td style="width:161px;">AR9352</td>
			<td></td>
		</tr>
		<tr height="60">
			<td height="60" style="height:60px;width:267px;">CellSave Preservative Tubes</td>
			<td style="width:175px;">Veridex</td>
			<td style="width:161px;">952820 (20 pack)&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; 79100005 (100 pack)</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:267px;">CellSearch CTC Control Kit</td>
			<td style="width:175px;">Veridex</td>
			<td style="width:161px;">7900003</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:267px;">CellSearch CTC Kit</td>
			<td style="width:175px;">Veridex</td>
			<td style="width:161px;">7900001</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:267px;">CellSearch CXC Control Kit</td>
			<td style="width:175px;">Veridex</td>
			<td style="width:161px;">7900018RUO</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:267px;">CellSearch CXC Kit</td>
			<td style="width:175px;">Veridex</td>
			<td style="width:161px;">7900017RUO</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:267px;">Instrument Buffer</td>
			<td style="width:175px;">Veridex</td>
			<td style="width:161px;">7901003</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:267px;">Streck Cell Preservative (aka CytoChex)</td>
			<td style="width:175px;">Streck</td>
			<td>213350</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:267px;"></td>
			<td style="width:175px;"></td>
			<td style="width:161px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:267px;">EQUIPMENT</td>
			<td style="width:175px;"></td>
			<td style="width:161px;"></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:267px;">1 ml syringe</td>
			<td style="width:175px;"></td>
			<td style="width:161px;"></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:267px;">10 ml serological pipette</td>
			<td style="width:175px;"></td>
			<td style="width:161px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:267px;">1000&#181;l pipette</td>
			<td style="width:175px;"></td>
			<td style="width:161px;"></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:267px;">1000&#181;l pipette tips</td>
			<td style="width:175px;"></td>
			<td style="width:161px;"></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:267px;">12 x 75mm flow tubes</td>
			<td style="width:175px;"></td>
			<td style="width:161px;"></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:267px;">200&#181;l gel loading tips</td>
			<td style="width:175px;"></td>
			<td style="width:161px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:267px;">200&#181;l pipette</td>
			<td style="width:175px;"></td>
			<td style="width:161px;"></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:267px;">22 gauge needle</td>
			<td style="width:175px;"></td>
			<td style="width:161px;"></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:267px;">5 3/4&#34; disposible pasteur pipet</td>
			<td style="width:175px;">VWR</td>
			<td style="width:161px;">14672-200</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:267px;">5 ml serological pipette</td>
			<td style="width:175px;"></td>
			<td style="width:161px;"></td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:267px;">Automated pipettor</td>
			<td style="width:175px;"></td>
			<td style="width:161px;"></td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:267px;">Capillary Blood Collection Tube (EDTA)</td>
			<td style="width:175px;">BD Microtainer</td>
			<td style="width:161px;">365974</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:267px;">CellSearch Analyzer II</td>
			<td style="width:175px;">Veridex</td>
			<td style="width:161px;">9555</td>
			<td rowspan="2" style="width:188px;">Includes magnests and verification cartirdges</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:267px;">CellSearch AutoPrep System</td>
			<td style="width:175px;">Veridex</td>
			<td style="width:161px;">9541</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:267px;">Centrifuge</td>
			<td style="width:175px;"></td>
			<td style="width:161px;"></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:267px;">MagCellect Magnet&#160;</td>
			<td style="width:175px;">R&#38;D Systems</td>
			<td style="width:161px;">MAG997</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:267px;">Small Latex Bulb</td>
			<td style="width:175px;">VWR</td>
			<td>82024-550</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:267px;">Vortex</td>
			<td style="width:175px;"></td>
			<td style="width:161px;"></td>
			<td></td>
		</tr>
	</tbody>
</table>

adaptation of semiautomated circulating tumor cell (ctc) assays for clinical and preclinical research applications

The majority of cancer-related deaths occur subsequent to the development of metastatic disease. This highly lethal disease stage is associated with the presence of circulating tumor cells (CTCs). These rare cells have been demonstrated to be of clinical significance in metastatic breast, prostate, and colorectal cancers. The current gold standard in clinical CTC detection and enumeration is the FDA-cleared CellSearch system (CSS). This manuscript outlines the standard protocol utilized by this platform as well as two&#160;additional adapted protocols that describe the detailed process of user-defined marker optimization for protein characterization of patient CTCs and a comparable protocol for CTC capture in very low volumes of blood, using standard CSS reagents, for studying in vivo preclinical mouse models of metastasis. In addition, differences in CTC quality between healthy donor blood spiked with cells from tissue culture versus patient blood samples are highlighted. Finally, several commonly discrepant items that can lead to CTC misclassification errors are outlined. Taken together, these protocols will provide a useful resource for users of this platform interested in preclinical and clinical research pertaining to metastasis and CTCs.

Standard CTC Enumeration Assay
The sensitivity and specificity of the CSS has been well documented in the literature. However, to validate equivalent CTC recovery, spiked (1,000 LNCaP human prostate cancer cells) and unspiked human blood samples from healthy volunteer donors were processed on the CSS using the standard CSSCTC protocol. As expected, unspiked samples were free of CTCs, 0.00&#177;0.00%, and CTC recovery was demonstrated to be 86.9&#177;4.71% for spiked samples (Figure 1A)</s...

Watch this Scientific Journal Video about Adaptation of Semiautomated Circulating Tumor Cell CTC Assays for Clinical and Preclinical Research Applications at JoVE.com

Adaptation of Semiautomated Circulating Tumor Cell CTC Assays for Clinical and Preclinical Research Applications

Circulating tumor cells (CTCs) are prognostic in several metastatic cancers. This manuscript describes the gold standard CellSearch system (CSS) CTC enumeration platform and highlights common misclassification errors. In addition, two&#160;adapted protocols are described for user-defined marker characterization of CTCs and CTC enumeration in preclinical mouse models of metastasis using this technology.

Adaptation of Semiautomated Circulating Tumor Cell (CTC) Assays for Clinical and Preclinical Research Applications

The majority of cancer-related deaths occur subsequent to the development of metastatic disease. This highly lethal disease stage is associated with the ...

Research

JoVE Journal

Medicine

Processing of Primary Brain Tumor Tissue for Stem Cell Assays and Flow Sorting

Brain tumors are typically comprised of morphologically diverse cells that express a variety of neural lineage markers. Only a relatively small fraction ...

Patient Derived Cell Culture and Isolation of CD133+ Putative Cancer Stem Cells from Melanoma

Patient Derived Cell Culture and Isolation of CD133+ Putative Cancer Stem Cells from Melanoma

Despite improved treatments options for melanoma available today, patients with advanced malignant melanoma still have a poor prognosis for ...

In vivo 19F MRI for Cell Tracking

In vivo 19F MRI for Cell Tracking

In vivo 19F MRI allows quantitative cell tracking without the use of ionizing radiation. It is a noninvasive technique that can be applied to humans. ...

A Novel in vivo Gene Transfer Technique and in vitro Cell Based Assays for the Study of Bone Loss in Musculoskeletal Disorders

A Novel in vivo Gene Transfer Technique and in vitro Cell Based Assays for the Study of Bone Loss in Musculoskeletal Disorders

Differentiation and activation of osteoclasts play a key role in the development of musculoskeletal diseases as these cells are primarily involved in bone ...

Isolation, Cryopreservation and Culture of Human Amnion Epithelial Cells for Clinical Applications

Human amnion epithelial cells (hAECs) derived from term or pre-term amnion membranes have attracted attention from researchers and clinicians as a ...

Ex Vivo Treatment Response of Primary Tumors and/or Associated Metastases for Preclinical and Clinical Development of Therapeutics

Ex Vivo Treatment Response of Primary Tumors and/or Associated Metastases for Preclinical and Clinical Development of Therapeutics

The molecular analysis of established cancer cell lines has been the mainstay of cancer research for the past several decades. Cell culture provides both ...

Isolation and Propagation of Circulating Tumor Cells from a Mouse Cancer Model

Cancer metastasis is the foremost cause of cancer-associated deaths. Recent studies have shown that circulating tumor cells (CTCs) are important in cancer ...

Generation of Prostate Cancer Patient Derived Xenograft Models from Circulating Tumor Cells

Patient derived xenograft (PDX) models are gaining popularity in cancer research and are used for preclinical drug evaluation, biomarker identification, ...

Preclinical Model of Hind Limb Ischemia in Diabetic Rabbits

Peripheral vascular disease is a widespread clinical problem that affects millions of patients worldwide. A major consequence of peripheral vascular ...

An Ex Vivo Tissue Culture Model for Fibrovascular Complications in Proliferative Diabetic Retinopathy

Diabetic retinopathy (DR) is the most common microvascular complication of diabetes and one of the leading causes of blindness in working-age adults. No ...