Chemokine 25–induced signaling suppresses colon cancer invasion and metastasis
Huanhuan Joyce Chen, … , Xiling Shen, Steven Lipkin
Huanhuan Joyce Chen, … , Xiling Shen, Steven Lipkin
Published August 6, 2012
Citation Information: J Clin Invest. 2012;122(9):3184-3196. https://doi.org/10.1172/JCI62110.
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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 1

CCR9 is expressed in early-stage CRC and early-stage CCICs.

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CCR9 is expressed in early-stage CRC and early-stage CCICs. (B) CCR9 pro...
(B) CCR9 protein in normal colon epithelium, (A and C) preinvasive, (D and E) invasive, and (F and G) liver metastatic CRCs is shown by immunohistochemistry with anti-human CCR9 and developed by DAB (brown). The dotted line in E indicates the boundary between normal epithelium (CCR9+) and invasive CRC (CCR9–). The box in D is shown at higher magnification in E . (H) Negative control with control IgG. Scale bars: 100 μm. (A, D, and F); 50 μm (E, G, and H); 10 μm (B and C). (I) CCR9 expression levels by immunohistochemistry scoring. Error bars indicate SEM. *P < 0.001, **P < 0.01, compared with normal colon. (J) FACS quantification of membrane and cytoplasmic CCR9+ cells in early- or late-stage primary CRCs. Gates are set for high CCR9+ signal intensity. Numbers indicate the percentage of CCR9+ cells (left) and CCR9– cells (right). (K) Western blot of CCR9 protein levels in common CRC lines (RKO, SW480, LoVo), 3 early-stage CCIC lines (stage I/II), and 2 late-stage CCIC lines (stage III/IV). β-Actin is used as loading control. Lymphoma cells were used as a positive control for CCR9. (L) FACS quantification of cell surface membrane CCR9+ cells in common CRC lines (HCT116 as representative), early-stage CCICs, and late-stage CCICs (early-stage CCIC1 and late-stage CCIC1, as representative). Numbers indicate the percentage of CCR9+ cells.