BACKGROUND AND PURPOSE: CD133 is controversially discussed as putative (surrogate) marker for cancer stem/tumor-initiating cell populations (CSC/TIC) in epithelial tumors including colorectal carcinomas (CRCs). We studied CD133 expression in established CRC cell lines and examined in vitro behavior, radioresponse and in vivo tumor formation of CD133(+/-) subpopulations of one cell line of interest. MATERIALS AND METHODS: Ten CRC cell lines were analyzed for CD133 expression using flow cytometry and Western blotting. CD133+ and CD133(-) HCT-116 subpopulations were separated by FACS and studied in 2-D and 3-D culture and colony formation assays after irradiation. Subcutaneous xenograft formation was monitored in NMRI (nu/nu) mice. RESULTS AND CONCLUSIONS: CRC cell lines could be classified into three groups: (i) CD133(-), (ii) CD133+ and (iii) those with two distinct CD133+ and CD133(-) subpopulations. Isolated CD133(+/-) HCT-116 subpopulations were studied relative to the original fraction. No difference was found in 2-D growth, spheroid formation or radioresponse in vitro. Also, tumor formation and growth rate did not differ for the sorted subpopulations. However, a subset of xenografts originated from CD133(-) HCT-116 showed a striking enrichment in the CD133+ fraction. Our data show that CD133 expression is not selective for sphere forming, tumor-initiating or radioresistant subpopulations in the HCT-116 CRC cell lines. This implies that CD133 cannot be regarded as a CSC/TIC marker in all CRC cell lines and that functional measurements of tumor formation have to generally accompany CSC/TIC-directed mechanistic or therapeutic studies.
BACKGROUND AND PURPOSE:CD133 is controversially discussed as putative (surrogate) marker for cancer stem/tumor-initiating cell populations (CSC/TIC) in epithelial tumors including colorectal carcinomas (CRCs). We studied CD133 expression in established CRC cell lines and examined in vitro behavior, radioresponse and in vivo tumor formation of CD133(+/-) subpopulations of one cell line of interest. MATERIALS AND METHODS: Ten CRC cell lines were analyzed for CD133 expression using flow cytometry and Western blotting. CD133+ and CD133(-) HCT-116 subpopulations were separated by FACS and studied in 2-D and 3-D culture and colony formation assays after irradiation. Subcutaneous xenograft formation was monitored in NMRI (nu/nu) mice. RESULTS AND CONCLUSIONS: CRC cell lines could be classified into three groups: (i) CD133(-), (ii) CD133+ and (iii) those with two distinct CD133+ and CD133(-) subpopulations. Isolated CD133(+/-) HCT-116 subpopulations were studied relative to the original fraction. No difference was found in 2-D growth, spheroid formation or radioresponse in vitro. Also, tumor formation and growth rate did not differ for the sorted subpopulations. However, a subset of xenografts originated from CD133(-) HCT-116 showed a striking enrichment in the CD133+ fraction. Our data show that CD133 expression is not selective for sphere forming, tumor-initiating or radioresistant subpopulations in the HCT-116 CRC cell lines. This implies that CD133 cannot be regarded as a CSC/TIC marker in all CRC cell lines and that functional measurements of tumor formation have to generally accompany CSC/TIC-directed mechanistic or therapeutic studies.
Authors: Alicia M Mihaliak; Candace A Gilbert; Li Li; Marie-Claire Daou; Richard P Moser; Andrew Reeves; Brent H Cochran; Alonzo H Ross Journal: Cancer Lett Date: 2010-10-28 Impact factor: 8.679
Authors: Thomas W Grunt; Alexandra Hebar; Sylvia Laffer; Renate Wagner; Barbara Peter; Harald Herrmann; Alexandra Graf; Martin Bilban; Martin Posch; Gregor Hoermann; Matthias Mayerhofer; Gregor Eisenwort; Christoph C Zielinski; Edgar Selzer; Peter Valent Journal: Am J Cancer Res Date: 2015-01-15 Impact factor: 6.166
Authors: Timo Gaiser; Jordi Camps; Sandra Meinhardt; Danny Wangsa; Quang Tri Nguyen; Sudhir Varma; Claudia Dittfeld; Leoni A Kunz-Schughart; Ralf Kemmerling; Maria R Becker; Kerstin Heselmeyer-Haddad; Thomas Ried Journal: Am J Pathol Date: 2011-04 Impact factor: 4.307