title: CD133+ colon cancer cells are more interactive with the tumor microenvironment than CD133- cells.
abstract: 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.
authors.affiliation: Department of Surgery, University of Texas Medical Branch, Galveston, TX 77555-0737, USA. cechao@utmb.edu
authors.forename: Celia
authors.initials: C
authors.lastname: Chao
authors.forename: J Russ
authors.initials: JR
authors.lastname: Carmical
authors.forename: Kirk L
authors.initials: KL
authors.lastname: Ives
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Wood
authors.forename: Judith F
authors.initials: JF
authors.lastname: Aronson
authors.forename: Guillermo A
authors.initials: GA
authors.lastname: Gomez
authors.forename: Clarisse D
authors.initials: CD
authors.lastname: Djukom
authors.forename: Mark R
authors.initials: MR
authors.lastname: Hellmich
mesh_terms: D000071916:AC133 Antigen; D000368:Aged; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism*; D002277:Carcinoma / Q000378:metabolism*; D018929:Cell Culture Techniques; D002471:Cell Transformation, Neoplastic; D002478:Cells, Cultured; D054377:Chemokine CXCL12 / Q000378:metabolism; D003110:Colonic Neoplasms / Q000378:metabolism*; D005260:Female; D005347:Fibroblasts / Q000378:metabolism; D020869:Gene Expression Profiling; D006023:Glycoproteins / Q000378:metabolism*; D006801:Humans; D008297:Male; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D019899:Paracrine Communication; D010455:Peptides / Q000378:metabolism*; D010641:Phenotype; D019718:Receptors, CXCR4 / Q000378:metabolism
chemical_list: D000071916:AC133 Antigen; D015703:Antigens, CD; C515255:CXCL12 protein, human; C527276:CXCR4 protein, human; D054377:Chemokine CXCL12; D006023:Glycoproteins; C000606023:PROM1 protein, human; D010455:Peptides; C000606024:Prom1 protein, mouse; D019718:Receptors, CXCR4