In vitro identification and characterization of CD133(pos) cancer stem-like cells in anaplastic thyroid carcinoma cell lines.
BACKGROUND
Recent publications suggest that neoplastic initiation and growth are dependent on a small subset of cells, termed cancer stem cells (CSCs). Anaplastic Thyroid Carcinoma (ATC) is a very aggressive solid tumor with poor prognosis, characterized by high dedifferentiation. The existence of CSCs might account for the heterogeneity of ATC lesions. CD133 has been identified as a stem cell marker for normal and cancerous tissues, although its biological function remains unknown.


RESULTS
ATC cell lines ARO, KAT-4, KAT-18 and FRO were analyzed for CD133 expression. Flow cytometry showed CD133(pos) cells only in ARO and KAT-4 (64+/-9% and 57+/-12%, respectively). These data were confirmed by qRT-PCR and immunocytochemistry. ARO and KAT-4 were also positive for fetal marker oncofetal fibronectin and negative for thyrocyte-specific differentiating markers thyroglobulin, thyroperoxidase and sodium/iodide symporter. Sorted ARO/CD133(pos) cells exhibited higher proliferation, self-renewal, colony-forming ability in comparison with ARO/CD133(neg). Furthermore, ARO/CD133(pos) showed levels of thyroid transcription factor TTF-1 similar to the fetal thyroid cell line TAD-2, while the expression in ARO/CD133(neg) was negligible. The expression of the stem cell marker OCT-4 detected by RT-PCR and flow cytometry was markedly higher in ARO/CD133(pos) in comparison to ARO/CD133(neg) cells. The stem cell markers c-KIT and THY-1 were negative. Sensitivity to chemotherapy agents was investigated, showing remarkable resistance to chemotherapy-induced apoptosis in ARO/CD133(pos) when compared with ARO/CD133(neg) cells.


CONCLUSIONS
We describe CD133(pos) cells in ATC cell lines. ARO/CD133(pos) cells exhibit stem cell-like features--such as high proliferation, self-renewal ability, expression of OCT-4--and are characterized by higher resistance to chemotherapy. The simultaneous positivity for thyroid specific factor TTF-1 and onfFN suggest they might represent putative thyroid cancer stem-like cells. Our in vitro findings might provide new insights for novel therapeutic approaches.
Zito
Giovanni
G
Laboratory of Molecular Endocrinology, Section of Endocrinology, DOSAC, University of Palermo, Palermo, Italy.
Richiusa
Pierina
P
Bommarito
Alessandra
A
Carissimi
Elvira
E
Russo
Leonardo
L
Coppola
Antonina
A
Zerilli
Monica
M
Rodolico
Vito
V
Criscimanna
Angela
A
Amato
Marco
M
Pizzolanti
Giuseppe
G
Galluzzo
Aldo
A
Giordano
Carla
C
D000071916:AC133 Antigen; D015703:Antigens, CD / Q000378:metabolism*; D000970:Antineoplastic Agents / Q000494:pharmacology; D014408:Biomarkers, Tumor / Q000032:analysis / Q000302:isolation & purification / Q000378:metabolism; D002277:Carcinoma / Q000378:metabolism / Q000473:pathology*; D018929:Cell Culture Techniques; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002469:Cell Separation; D005353:Fibronectins / Q000378:metabolism / Q000502:physiology; D006023:Glycoproteins / Q000378:metabolism*; D006801:Humans; D014411:Neoplastic Stem Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D009687:Nuclear Proteins / Q000378:metabolism / Q000502:physiology; D010455:Peptides / Q000378:metabolism*; D013964:Thyroid Neoplasms / Q000378:metabolism / Q000473:pathology*; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors / Q000378:metabolism / Q000502:physiology; D014410:Tumor Stem Cell Assay
D000071916:AC133 Antigen; D015703:Antigens, CD; D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D005353:Fibronectins; D006023:Glycoproteins; C000614412:NKX2-1 protein, human; D009687:Nuclear Proteins; C000606023:PROM1 protein, human; D010455:Peptides; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors; C121542:oncofetal fibronectin