Both CD133⁺ and CD133⁻ subpopulations of A549 and H446 cells contain cancer‐initiating cells

Abstract

Tumors have been known to contain a small population of cancer stem cells that initiate tumor growth and promote tumor spreading. CD133 alone or in combination with other markers is currently being used for identification and isolation of the putative cancer stem cell population from malignant tumors. CD133 is a member of the transmembrane glycoprotein family and was initially described as a surface antigen specific for human hematopoietic stem cells.(1,2) Although its biological function remains largely unknown, CD133 has been recognized as a stem cell marker for cancerous tissues. Indeed, CD133 alone or in combination with other markers is currently used for identification and isolation of the putative cancer stem cell population from malignant tumors, as well as cell lines of brain, (3,4) prostate, (5) liver, (6,7) pancreas, (8) colon (9,10) and melanoma.In a recent report, CD133 was also used to isolate cancer stem cells from lung cancer.(12) The lung cancer CD133 + subpopulation was able to grow indefinitely as tumor spheres in serum-free medium containing epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF). When injected into immunocompromised mice, they readily generated xenograft tumor phenotypically identical to the tumor derived from the original unsorted cancer cells. Upon differentiation, lung cancer CD133 + cells acquired the specific lineage markers, while losing the tumorigenic potential together with the CD133 expression. (12) However, in one recent study on different in vitro phenotypes of primary glioblastomas, although most primary cells grown as tumor spheres were driven by CD133 + cells, four of the 15 cell lines grown adherently were driven by stem cell-like CD133 -tumor cells (13) and both the CD133 + and CD133 -tumor cells from these cells were similarly tumorigenic in nude mice in vivo.(13) It was also reported that both CD133 + and CD133 -metastatic colon tumor subpopulations formed colonospheres in cultures and were capable of long-term tumorigenesis in a NOD/SCID serial xenotransplantation model. (14) Furthermore, both CD133 + and CD133 -cells displayed similar frequencies of stem cell-like properties in DAOY medulloblastoma cell line.(15) Given the contradiction regarding the role of CD133 as a true cancer stem cell marker, we investigated whether the CD133 + subpopulations of a non-small cell lung cancer A549 cell line and a small lung cancer H446 cell line characteristically resemble the cancer stem cells more closely than the CD133 -subpopulations. Materials and MethodsCell culture. Human lung cancer cell lines A549 and H446 were cultured in RPMI-1640 (HyClone, Logan, UT, USA) and 10% fetal bovine serum (Tian Jin Hao Yang Biological Manufacture, Tian Jin, China) in a tissue culture incubator at 37°C under 5% CO 2 and 100% humidity. To determine the clonogenicity and regeneration ability of single cells, colony formation assay was carried out as described previously (16) with some modifications. CD133 + and CD133 -cells of A549 and H446 were resuspended in fres...

CD133 positive cells isolated from A549 cell line exhibited high liver metastatic potential

“…Our results showed that CD133 + cells isolated from A549 cells by flow cytometry which accounting for a small percentage of A549 cells at 1.8 % which was consistent with previous reports, where the proportion was between 0.98 %~3.9 % [10,16,17]. The tumorigenicity of the tumor cell lines was enhanced after in vivo passage which was reported in previous studies [18][19][20][21].…”

“…It need to be noticed that Meng et al studied the CD133 + and CD133 -A549 cells and found that they exhibited similar abilities of colony formation, invasion [16]. The difference may lie in two aspects: firstly, they use the sub-cloning method to acquire the cells for colony formation and tumorigenicity assay, which have been screened with high ability in forming colonies and was nearly no correlation with the marker they expressed; Secondly, the obtained A549 CD133 + cells in our study were cultured and maintained in serum-free medium supplemented with B27 and A549 cells and cultured in a medium containing serum.…”

CD44 and CD24 cannot act as cancer stem cell markers in human lung adenocarcinoma cell line A549

“…CD44 + /CD24 + and CD44 + /CD24 -/low subpopulations derived from cell line A549 were characterized using their colony-and sphere-formation potential. CD133 is the most commonly reported cell surface marker that has been used to isolate CSCs from lung cancer cell lines and fresh tumor samples, but there is no consensus on the level of CD133 expression in cell line A549 [7,12,[32][33][34][35][36]. Our data demonstrate that 0.94% of A549 cells expressed the CD133 marker.…”

Monitoring microRNAs Using a Molecular Beacon in CD133+/CD338+Human Lung Adenocarcinoma-initiating A549 Cells

“…The CD133 + cells from fresh lung tumor samples were also found to have tumor-initiating properties in both small cell and non-small cell lung cancers (Eramo et al, 2008). However, some evidence has indicated that the ability of CD133 + expression to discriminate lung TICs may have been overestimated (Sullivan et al, 2010) and that CD133 + cells do not represent TICs (Meng et al, 2009). Thus, the CD133 marker should be combined with other cell surface markers for the isolation and identification of lung TICs.…”