To reveal the molecular machinery underlying the stem-like features in tumor cells, we analyzed a promoter of CD133 gene using human colon carcinoma Caco-2 and synovial sarcoma Fuji cells, which endogenously express CD133 gene.
We found that RAC3 overexpression was mainly associated to CD133+ side-population of colon cancer cells and also to early and advanced stages of colon cancer, involving increased expression of mesenchymal and stem markers.
Together, our present observations strongly suggest that the CD133-PTPRK axis plays a pivotal role in the regulation of colon cancer progression as well as drug resistance.
In vivo, Plk1 inhibitors killed CD133(+) colon cancer cells leading to complete growth arrest of colon cancer stem cell-derived xenografts, whereas chemotherapeutic agents only slowed tumor progression.
However, sorted CD133+ colon cancer cells exhibit no increased resistance to 5-FU, and CD133 levels exhibit no correlation with colon cancer patient survival or cancer recurrence.
Automated FISH analysis was performed on 13 different colon cancer samples that had been stained for CD133; each sample was scored for MYC, ZNF217 and Chromosome 6 in CD133 positive and negative glands.
Here, using a human colon carcinoma HT-29 model, we demonstrated that the intratumoral (64)Cu-ATSM high-uptake regions exhibited malignant characteristics, such as upregulated DNA repair and elevated %CD133(+) cancer stem-like cells.
CD66c was absent in CD133-positive cells that were isolated from normal colon, whereas its expression was brightest (CD66c(bright) ) in CD133-positive cells from colon cancer samples.
Various differentially expressed genes were identified and the most relevant transcripts found to be over-expressed in CD133(+) cells were evaluated by quantitative RT-PCR in the CD133(+) fractions isolated from several CC cell lines.
Using the CD133 siRNA knockdown strategy and non-differentiated human colon cancer Caco-2 cells that constitutively over-expressed CD133, we provide for the first time direct evidence for a role of CD133 in the intracellular accumulation of fluorescently labeled extracellular compounds.
CD133-containing MVs induced the development of chemoresistance by abolishing the inhibitory effects of anti-epidermal growth factor receptor (EGFR) drugs on cell proliferation and motility in colon cancer.
Recent studies suggest CD133, a surface protein widely used for isolation of colon cancer stem cells, to be associated with tumor angiogenesis and recurrence.
In conclusion, the human colon cancer cell line, SW620, contains both CD133(+) and CD133(-) phenotypes, and the CD133(+) phenotype has characteristics consistent with those of cancer stem cells.