Biological heterogeneity of putative bladder cancer stem‐like cell populations from human bladder transitional cell carcinoma samples

Abstract

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. (Cancer Sci 2010; 101: 416-424) B ladder cancer is the fifth most common tumor in the USA, accounting for 5-10% of all malignancies.(1)Histologically, more than 90% of bladder cancers are epithelial transitional cell carcinomas (TCC). Superficial TCC is heterogeneous in molecular pathogenesis and 60-90% of patients will have a tumor recurrence if treated by transurethral resection alone.(2)The high frequency of recurrence of superficial TCC of the bladder and its heterogeneous presentation prompted us to suppose that stem cells (or cells that by mutation acquired stem peculiarities) could be involved in the development of this kind of tumor. Cancer stem cells (CSCs) constitute a rare population of undifferentiated tumorigenic cells responsible for tumor initiation, maintenance, and spreading.(3) For tumors containing a subpopulation of CSCs, there are at least two proposed mechanisms for how the CSCs could have arisen: oncogenic mutations that inactivate the constraints on normal stem cell expansion; or, in a more differentiated cell, oncogenic mutations could generate continual proliferation of cells that no longer enter a postmitotic differentiated state, thereby creating a pool of selfrenewing cells in which further mutations can accumulate. Current failure of cancer therapies might be due to their lower effect on CSCs that retain their full capacity to undergo and to restore the tumor cell mass. The development of ...

ALDH1 in Combination with CD44 as Putative Cancer Stem Cell Markers are Correlated with Poor Prognosis in Urothelial Carcinoma of the Urinary Bladder

“…Cancer stem cells (CSCs) or tumor-initiating cells are subpopulation of undifferentiated tumorigenic cells within the tumors that represent unique characteristics such as tumor-initiation, self-renewal, and the ability of proliferation which are responsible for tumor progression, relapse, metastasis and also tumor heterogeneity resulting from differentiation (Heppner, 1984;Reya et al, 2001;Clarke et al, 2006;Jordan et al, 2006;Dwyer et al, 2007;Chang et al, 2008;Bentivegna et al, 2010;Bohl et al, 2011;Ho et al, 2012;Madjd et al, 2013). CSCs also mediate tumor resistance to common treatments such as chemotherapy and radiation (Bao et al, 2006;Li et al, 2008;Bentivegna et al, 2010;Ho et al, 2012;Madjd et al, 2013).…”

“…CSCs also mediate tumor resistance to common treatments such as chemotherapy and radiation (Bao et al, 2006;Li et al, 2008;Bentivegna et al, 2010;Ho et al, 2012;Madjd et al, 2013). In a large number of studies, CSCs have been isolated from patient specimens, cancer cell lines and xenografts using fluorescence-activated cell sorting (FACS) and with a combination of suitable cell surface markers, cytokeratin markers, drug transporters and side population (SP) in Hoechst 33342 staining (Yang and Chang, 2008;Su et al, 2010;Ho et al, 2012;Luo et al, 2012;Zhang et al, 2012).…”

Prognostic Significance of Nestin Expression in pT1 High-Grade Bladder Urothelial Carcinoma Patients Treated with Intravesical BCG

“…From urological point of view, reduction of nestin expression has been shown to be correlated with decreased invasion and migration capability of prostate cancer cells (Gravdal et al, 2009). Furthermore, it has been detected as a stem cell marker in 100% of bladder cancer cell cultures which may suggest a possible role in bladder cancer pathogenesis (Bentivegna et al, 2010). There is also one case reported with osteoclast-rich undifferentiated carcinoma of the bladder and nestin expression (Kawano et al, 2011).…”

Growth, Clonability, and Radiation Resistance of Esophageal Carcinoma-derived Stem-like Cells

“…Soft agar cloning experiments are typically used to detect the growth of non-adherent of tumor cells (Bentivegna et al, 2010;Toivanen et al, 2011). Not all tumor cells have the ability to form colonies in soft agar; colony formation of tumor cells is positively correlated with their tumorigenic ability (Freedman et al, 1974).…”