An In Vivo CRISPR Screen Identifies Stepwise Genetic Dependencies of Metastatic Progression

Cancer Res. 2022 Feb 15;82(4):681-694. doi: 10.1158/0008-5472.CAN-21-3908.


Blood-borne metastasis of breast cancer involves a series of tightly regulated sequential steps, including the growth of a primary tumor lesion, intravasation of circulating tumor cells (CTC), and adaptation in various distant metastatic sites. The genes orchestrating each of these steps are poorly understood in physiologically relevant contexts, owing to the rarity of experimental models that faithfully recapitulate the biology, growth kinetics, and tropism of human breast cancer. Here, we conducted an in vivo loss-of-function CRISPR screen in newly derived CTC xenografts, unique in their ability to spontaneously mirror the human disease, and identified specific genetic dependencies for each step of the metastatic process. Validation experiments revealed sensitivities to inhibitors that are already available, such as PLK1 inhibitors, to prevent CTC intravasation. Together, these findings present a new tool to reclassify driver genes involved in the spread of human cancer, providing insights into the biology of metastasis and paving the way to test targeted treatment approaches.

Significance: A loss-of-function CRISPR screen in human CTC-derived xenografts identifies genes critical for individual steps of the metastatic cascade, suggesting novel drivers and treatment opportunities for metastatic breast cancers.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biomarkers, Tumor / genetics*
  • Biomarkers, Tumor / metabolism
  • Breast Neoplasms / blood
  • Breast Neoplasms / genetics*
  • Breast Neoplasms / pathology
  • CRISPR-Cas Systems
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism
  • Cell Line, Tumor
  • Clustered Regularly Interspaced Short Palindromic Repeats / genetics*
  • Female
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Mice, Inbred NOD
  • Mice, Knockout
  • Mice, SCID
  • Neoplasm Metastasis
  • Neoplastic Cells, Circulating / metabolism*
  • Neoplastic Cells, Circulating / pathology
  • Protein Serine-Threonine Kinases / genetics
  • Protein Serine-Threonine Kinases / metabolism
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins / metabolism
  • RNA, Guide / genetics
  • RNA, Guide / metabolism
  • RNA-Seq / methods
  • Survival Analysis
  • Xenograft Model Antitumor Assays / methods


  • Biomarkers, Tumor
  • Cell Cycle Proteins
  • Proto-Oncogene Proteins
  • RNA, Guide
  • Protein Serine-Threonine Kinases
  • polo-like kinase 1