Chemokine 25–induced signaling suppresses colon cancer invasion and metastasis
Huanhuan Joyce Chen, Robert Edwards, Serena Tucci, Pengcheng Bu, Jeff Milsom, Sang Lee, Winfried Edelmann, Zeynep H. Gümüs, Xiling Shen, Steven Lipkin
Huanhuan Joyce Chen, Robert Edwards, Serena Tucci, Pengcheng Bu, Jeff Milsom, Sang Lee, Winfried Edelmann, Zeynep H. Gümüs, Xiling Shen, Steven Lipkin
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Research Article Oncology

Chemokine 25–induced signaling suppresses colon cancer invasion and metastasis

Abstract

Chemotactic cytokines (chemokines) can help regulate tumor cell invasion and metastasis. Here, we show that chemokine 25 (CCL25) and its cognate receptor chemokine receptor 9 (CCR9) inhibit colorectal cancer (CRC) invasion and metastasis. We found that CCR9 protein expression levels were highest in colon adenomas and progressively decreased in invasive and metastatic CRCs. CCR9 was expressed in both primary tumor cell cultures and colon-cancer-initiating cell (CCIC) lines derived from early-stage CRCs but not from metastatic CRC. CCL25 stimulated cell proliferation by activating AKT signaling. In vivo, systemically injected CCR9+ early-stage CCICs led to the formation of orthotopic gastrointestinal xenograft tumors. Blocking CCR9 signaling inhibited CRC tumor formation in the native gastrointestinal CCL25+ microenvironment, while increasing extraintestinal tumor incidence. NOTCH signaling, which promotes CRC metastasis, increased extraintestinal tumor frequency by stimulating CCR9 proteasomal degradation. Overall, these data indicate that CCL25 and CCR9 regulate CRC progression and invasion and further demonstrate an appropriate in vivo experimental system to study CRC progression in the native colon microenvironment.

Authors

Huanhuan Joyce Chen, Robert Edwards, Serena Tucci, Pengcheng Bu, Jeff Milsom, Sang Lee, Winfried Edelmann, Zeynep H. Gümüs, Xiling Shen, Steven Lipkin

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Figure 4

CCL25-dependent chemotaxis in early-stage primary CRC and CCICs.

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CCL25-dependent chemotaxis in early-stage primary CRC and CCICs. (A) Boy...
(A) Boyden chamber assay of 7 early-stage primary CRCs in the upper chambers chemotaxis to the lower chambers containing CCL25. CCL25 absence is indicated by “–”; CCL25 presence is indicated by “+”. Error bars indicate SEM. *P < 0.0001, compared with matched (–) cells by 1-way ANOVA (n = 4). SW480 was used as a negative control. (B) Crystal violet staining of early-stage primary CRC cells migrating into the chamber with CCL25 (bottom) or mock (top). Scale bar: 50 μm. (C) CEA (red) and CCR9 (green) immunofluorescence of early-stage primary CRC cells that migrated to the chamber with CCL25 (DAPI [blue]). Scale bar: 10 μm. IgG was used as negative control. (D) Crystal violet staining of Transwell chambers with early-stage CCIC1 or late-stage CCIC1 (as representatives) that have migrated to CCL25 or PBS (mock). Scale bar: 50 μm. (E) CCR9 (green) immunofluorescence of early-stage CCICs that migrated to the CCL25-containing chamber (DAPI [blue]). Control IgG was used as negative control. Scale bar: 10 μm. (F) Percentage of early- or late-stage CCICs that migrated to CCL25 or mock (PBS) in Transwell assay. **P < 0.001.