CD133+ colon cancer cells are more interactive with the tumor microenvironment than CD133− cells

• Published in: Laboratory investigation 2012-03, Vol.92 (3), p.420-436
• Main Authors: Chao, Celia, Carmical, J Russ, Ives, Kirk L, Wood, Thomas G, Aronson, Judith F, Gomez, Guillermo A, Djukom, Clarisse D, Hellmich, Mark R
• Format: Article
• Language: English
• Subjects: AC133 Antigen; Aged; Animals; Antigens, CD - metabolism; Biological and medical sciences; Biotechnology; Carcinoma - metabolism; CD133; Cell Culture Techniques; Cell Transformation, Neoplastic; Cells, Cultured; Chemokine CXCL12 - metabolism; colon cancer; Colonic Neoplasms - metabolism; CXCR4; Female; Fibroblasts - metabolism; Fundamental and applied biological sciences. Psychology; Gastroenterology. Liver. Pancreas. Abdomen; Gene Expression Profiling; Glycoproteins - metabolism; Humans; Investigative techniques, diagnostic techniques (general aspects); Laboratory Medicine; Male; Medical sciences; Medicine; Medicine & Public Health; Mice; Mice, Inbred NOD; Mice, SCID; Paracrine Communication; Pathology; Peptides - metabolism; Phenotype; Receptors, CXCR4 - metabolism; research-article; Stomach. Duodenum. Small intestine. Colon. Rectum. Anus; tumor microenvironment; Tumors
• ISSN: 0023-6837; 1530-0307
• DOI: 10.1038/labinvest.2011.185

Experimental data indicate that colorectal cancer cells with CD133 expression exhibit enhanced tumorigenicity over CD133-negative (CD133−) cells. We hypothesized that CD133-positive (CD133+) cells, compared with CD133−, are more tumorigenic because they are more interactive with and responsive to their stromal microenvironment. Freshly dissected and dissociated cells from a primary colon cancer were separated into carcinoma-associated fibroblasts (CAF) and the epithelial cells; the latter were further separated into CD133+ and CD133− cells using fluorescence-activated cell sorter. The CD133+ cells formed large tumors in non-obese diabetic-severe combined immunodeficient (NOD-SCID) mice, demonstrating the phenotypic cellular diversity of the original tumor, whereas CD133− cells were unable to sustain significant growth. Affymetrix gene array analyses using t-test, fold-change and multiple test correction identified candidate genes that were differentially expressed between the CD133+ vs CD133− cells. RT-PCR verified differences in expression for 30 of the 46 genes selected. Genes upregulated (+ vs – cells) included CD133 (9.3-fold) and CXCR4 (4-fold), integrin β8 and fibroblast growth factor receptor 2. The CAF highly express the respective ligands: stromal-derived factor-1 (SDF-1), vitronectin and FGF family members, suggesting a reciprocal relationship between the CD133+ and CAF cells. SDF-1 caused an increase in intracellular calcium in cells expressing both CD133 and CXCR4, confirming functional CXCR4. The CD133+/CXCR4+ phenotype is increased to 32% when the cells are grown in suspension compared with only 9% when the cells were allowed to attach. In Matrigel 3-D culture, the CD133+/CXCR4+ group treated with SDF-1 grew more colonies compared with vehicle, as well as significantly larger colony sizes of tumor spheres. These data demonstrate proof of principle that the enhanced tumorigenic potential of CD133+, compared with CD133−, cells is due to their increased ability to interact with their neighboring CAF.