Single-cell analysis of circulating tumor cells identifies cumulative expression patterns of EMT-related genes in metastatic prostate cancer

Authors

  • Chun-Liang Chen,

    1. Department of Molecular Medicine, Cancer Therapy and Research Center, University of Texas Health Science Center, San Antonio, Texas
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  • Devalingam Mahalingam,

    1. Department of Medicine, Cancer Therapy and Research Center, University of Texas Health Science Center, San Antonio, Texas
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  • Pawel Osmulski,

    1. Department of Molecular Medicine, Cancer Therapy and Research Center, University of Texas Health Science Center, San Antonio, Texas
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  • Rohit R. Jadhav,

    1. Department of Molecular Medicine, Cancer Therapy and Research Center, University of Texas Health Science Center, San Antonio, Texas
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  • Chiou-Miin Wang,

    1. Department of Molecular Medicine, Cancer Therapy and Research Center, University of Texas Health Science Center, San Antonio, Texas
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  • Robin J. Leach,

    1. Department of Cellular and Structural Biology, Cancer Therapy and Research Center, University of Texas Health Science Center, San Antonio, Texas
    2. Department of Urology, Cancer Therapy and Research Center, University of Texas Health Science Center, San Antonio, Texas
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  • Tien-Cheng Chang,

    1. Department of Obstetrics and Gynecology, Cancer Therapy and Research Center, University of Texas Health Science Center, San Antonio, Texas
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  • Steven D. Weitman,

    1. Department of Pediatrics, Cancer Therapy and Research Center, University of Texas Health Science Center, San Antonio, Texas
    2. Department of Institute for Drug Development, Cancer Therapy and Research Center, University of Texas Health Science Center, San Antonio, Texas
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  • Addanki Pratap Kumar,

    1. Department of Urology, Cancer Therapy and Research Center, University of Texas Health Science Center, San Antonio, Texas
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  • LuZhe Sun,

    1. Department of Cellular and Structural Biology, Cancer Therapy and Research Center, University of Texas Health Science Center, San Antonio, Texas
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  • Maria E. Gaczynska,

    1. Department of Molecular Medicine, Cancer Therapy and Research Center, University of Texas Health Science Center, San Antonio, Texas
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  • Ian M. Thompson,

    1. Department of Urology, Cancer Therapy and Research Center, University of Texas Health Science Center, San Antonio, Texas
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  • Tim Hui-Ming Huang

    Corresponding author
    1. Department of Molecular Medicine, Cancer Therapy and Research Center, University of Texas Health Science Center, San Antonio, Texas
    • Department of Molecular Medicine/Institute of Biotechnology, University of Texas Health Science Center, 7703 Floyd Curl Drive, Mail Code 8257, STRF, San Antonio 78229-3900, TX.
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Abstract

BACKGROUND

Prostate tumors shed circulating tumor cells (CTCs) into the blood stream. Increased evidence shows that CTCs are often present in metastatic prostate cancer and can be alternative sources for disease profiling and prognostication. Here we postulate that CTCs expressing genes related to epithelial–mesenchymal transition (EMT) are strong predictors of metastatic prostate cancer.

METHODS

A microfiltration system was used to trap CTCs from peripheral blood based on size selection of large epithelial-like cells without CD45 leukocyte marker. These cells individually retrieved with a micromanipulator device were assessed for cell membrane physical properties using atomic force microscopy. Additionally, 38 CTCs from eight prostate cancer patients were used to determine expression profiles of 84 EMT-related and reference genes using a microfluidics-based PCR system.

RESULTS

Increased cell elasticity and membrane smoothness were found in CTCs compared to noncancerous cells, highlighting their potential invasiveness and mobility in the peripheral circulation. Despite heterogeneous expression patterns of individual CTCs, genes that promote mesenchymal transitioning into a more malignant state, including IGF1, IGF2, EGFR, FOXP3, and TGFB3, were commonly observed in these cells. An additional subset of EMT-related genes (e.g., PTPRN2, ALDH1, ESR2, and WNT5A) were expressed in CTCs of castration-resistant cancer, but less frequently in castration-sensitive cancer.

CONCLUSIONS

The study suggests that an incremental expression of EMT-related genes in CTCs is associated with metastatic castration-resistant cancer. Although CTCs represent a group of highly heterogeneous cells, their unique EMT-related gene signatures provide a new opportunity for personalized treatments with targeted inhibitors in advanced prostate cancer patients. Prostate 73: 813–826, 2013. © 2012 Wiley Periodicals, Inc.

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