The critical roles of tumor-initiating cells and the lymph node stromal microenvironment in human colorectal cancer extranodal metastasis using a unique humanized orthotopic mouse model

FASEB J. 2015 Aug;29(8):3571-81. doi: 10.1096/fj.14-268938. Epub 2015 May 11.


Colorectal cancer (CRC) is the second-most common cause of cancer-related mortality. The most important prognostic factors are lymph node (LN) involvement and extranodal metastasis. Our objective is to investigate the interactions between CD133(+)CXCR4(+) (CXC receptor 4) colorectal cancer tumor-initiating cells (Co-TICs) and the LN stromal microenvironment in human CRC extranodal metastasis. We established a unique humanized orthotopic xenograft model. Luciferase-tagged CRC cell lines and human cancer cells were injected intrarectally into nonobese diabetic/SCID mice. Mesenteric LN stromal cells, stromal cell line HK, or CXCL12 knockdown HK (HK-KD-A3) cells were coinoculated with CRC cells. Tumor growth and metastasis were monitored by bioluminescent imaging and immunohistochemistry. We found that this model mimics the human CRC metastatic pattern with CRC cell lines or patient specimens. Adding LN stromal cells promotes CRC tumor growth and extranodal metastasis (P < 0.001). Knocking down CXCL12 impaired HK cell support of CRC tumor formation and extranodal metastasis. When HK cells were added, sorted CD133(+)CXCR4(+) Co-TICs showed increased tumor formation and extranodal metastasis capacities compared to unseparated and non-Co-TIC populations. In conclusion, both Co-TIC and LN stromal factors play crucial roles in CRC metastasis through the CXCL12/CXCR4 axis. Blocking Co-TIC/LN-stromal interactions may lead to effective therapy to prevent extranodal metastasis.

Keywords: HK cell; cancer stem cell; intrarectal injection; xenograft.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • AC133 Antigen
  • Animals
  • Antigens, CD / metabolism
  • Cell Line, Tumor
  • Cell Movement / physiology
  • Cellular Microenvironment / physiology*
  • Chemokine CXCL12 / metabolism
  • Colorectal Neoplasms / metabolism
  • Colorectal Neoplasms / pathology*
  • Disease Models, Animal
  • Glycoproteins / metabolism
  • HT29 Cells
  • Humans
  • Lymph Nodes / metabolism
  • Lymph Nodes / pathology*
  • Lymphatic Metastasis / pathology*
  • Mice
  • Mice, Inbred NOD
  • Mice, SCID
  • Neoplastic Stem Cells / metabolism
  • Neoplastic Stem Cells / pathology*
  • Peptides / metabolism
  • Receptors, CXCR4 / metabolism
  • Stromal Cells / metabolism
  • Stromal Cells / pathology*


  • AC133 Antigen
  • Antigens, CD
  • Chemokine CXCL12
  • Glycoproteins
  • PROM1 protein, human
  • Peptides
  • Prom1 protein, mouse
  • Receptors, CXCR4