Biological heterogeneity of putative bladder cancer stem-like cell populations from human bladder transitional cell carcinoma samples.
Transitional cell carcinoma (TCC) is the most common type of bladder cancer. Emerging evidence has suggested that the capability of a tumor to grow and propagate is dependent on a small subset of cells, the cancer stem-like cells (CSCs) or tumor initiating cells. We report on the isolation and biological characterization of putative bladder CSC populations from primary TCCs. Isolated cells were induced to proliferate in stem cell culture conditions (serum-free medium containing mitogenic growth factors). The proliferating cells formed spheroids (urospheres) and their abilities for extensive proliferation and self-renewal were assayed. Their positivity for several stem cell markers (CD133, Oct-3/4, nestin, and cytokeratins) was also assessed by immunofluorescence tests and they could have the potential to differentiate in the presence of serum. In stem cell culture conditions they gradually showed loss of proliferation, adherence to the substrate, and morphological changes, which might reflect their progressive acquisition of differentiative capacity and loss of self-renewal ability. To evaluate if effective cell selection occurred after isolation, conventional cytogenetic studies on fresh chromosome spreads immediately after isolation and after culture were carried out. In addition, a molecular cytogenetic study by UroVysion assay was carried out on paraffin-embedded tissue sections and on fresh and after culture nuclei preparations. The data collected indicated important karyotype changes and a positive selection for hypo- or near-diploid cells, losing the complexity present in fresh tumors.
Bentivegna
Angela
A
Dipartimento di Neuroscienze e Tecnologie Biomediche, Università degli Studi di Milano-Bicocca, Monza, Italy.
Conconi
Donatella
D
Panzeri
Elena
E
Sala
Elena
E
Bovo
Giorgio
G
Viganò
Paolo
P
Brunelli
Silvia
S
Bossi
Mario
M
Tredici
Giovanni
G
Strada
Guido
G
Dalprà
Leda
L
D000071916:AC133 Antigen; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D015703:Antigens, CD / Q000032:analysis; D002295:Carcinoma, Transitional Cell / Q000235:genetics / Q000473:pathology*; D002454:Cell Differentiation; D002869:Chromosome Aberrations; D005260:Female; D006023:Glycoproteins / Q000032:analysis; D006801:Humans; D008297:Male; D051379:Mice; D008875:Middle Aged; D014411:Neoplastic Stem Cells / Q000473:pathology*; D010455:Peptides / Q000032:analysis; D001749:Urinary Bladder Neoplasms / Q000235:genetics / Q000473:pathology*
D000071916:AC133 Antigen; D015703:Antigens, CD; D006023:Glycoproteins; C000606023:PROM1 protein, human; D010455:Peptides; C000606024:Prom1 protein, mouse