[Cancer stem cells: its existence, proliferation and differentiation in an adenoid cystic carcinoma cell line].
OBJECTIVE
To investigate the evidences of the presence of tumor stem cells and its impact on the tumorigenesis of adenoid cystic carcinoma cell (ACC)-2 cell line by analyzing the biologic characteristics of different sub-clones of adenoid cystic carcinoma cell line.


METHODS
In vitro individual cell culture was employed to observe the proliferating character of ACC-2 cells. The expression of CD44(+) and CD24(-) of ACC-2 cells were investigated by immunohistochemical. Immunomagnetic isolation of different phenotype of ACC-2 cells, followed by cell culture, was used to study the proliferating abilities of different clusters of the cell line. The hetero-transplanted tumor mold was established using BALB/C nude mice by subcutaneous injection of tumor cells. The tumorigenic and differentiating properties of the different cluster were investigated.


RESULTS
Only 4.41% of cultured ACC-2 cell had ability of division, proliferation and establishment of cell clone. CD44(+)-CD24(-) cluster accounted for about 8.1% of total ACC-2 cells, among which, 25.71% cells could divide and proliferate. All of CD44 and CD44(+)-CD24(+) cells were failure to be eternal alive in the condition of in vitro individual cell culture. According to the results of in vivo tumorigenic study, the minimal cell quantity to develop a subcutaneous transplanted tumor by CD44(+)-CD24(-) cells was 1 x 10(3), where as the needed cell amount were 1 x 10(5) and 1 x 10(4) as to non-isolated ACC-2 cells and CD44(+) cells, respectively. The CD44(-) and CD44(+)-CD24(+) did not develop transplanted tumors. CD44(+)-CD24(-) ACC-2 cell could differentiate into cells of other phenotypes.


CONCLUSIONS
CD44(+)-CD24(-) ACC-2 cells consist of a very small portion of all ACC-2 cells (about 4%). They have remarkable proliferating ability and can bear special phenotypes, The tumorogenic ability of CD44(+)-CD24(-) cells are stronger than that of CD44(+) and non-isolated ACC-2 cells. Eliminating of this cluster from ACC-2 would actually deprive the tumorogenic ability of the cell line.
Department of Oral and Maxillo-Head and Neck Oncology, West China School of Stomatology, Sichuan University, Chengdu, China.
Kun
K
Liu
Cheng-Ge
CG
Hua
Yu-Ming
YM
Wen
Jian
J
Pan
Shao-Wei
SW
Chen
Qing-Hong
QH
Gao
D000818:Animals; D003528:Carcinoma, Adenoid Cystic / Q000473:pathology*; D002454:Cell Differentiation; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009062:Mouth Neoplasms / Q000473:pathology; D014411:Neoplastic Stem Cells / Q000473:pathology*; D023041:Xenograft Model Antitumor Assays