Ps-90: The CD44/24 Populations Isolated from A549 Cell Line Exhibit Similar Capacity In Vitro Studies


Roudi R *, Madjd Z , Ebrahimi M , Samadikuchaksaraei A ,

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Objective: Lung cancer is the leading cause of cancer- related death worldwide. Cancer stem cells (CSC) are a rare population of undifferentiated tumorigenic cells responsible for tumor initiation, maintenance and spreading. We aimed to identify stem-like populations in A549, as human lung adenocarcinoma epithelial cell line, and to investigate CSC features including expression of putative surface markers, clonogenic and sphere forming capacity of these populations. Materials and Methods: Non-sorted A549 cells were studied for clonogenic and sphere forming capacity. Flow cytometric profiles for CSC markers aldehyde dehydrogenase 1(ALDH1), CD24, CD29, CD44, CD49, CD133 and ABCG-2 were determined in A549 cell line. Cells were sorted and assessed for clonogenic and sphere forming capacity. Results: In non-sorted A549 cells, clonogenic and sphere forming capacity were 49.58% and 0.01% respectively. Expression of ALDH1Variant activity exhibited a range from 0.5% to 21.3%. CD44+ (69.54%-97.6%) and CD24+ (55.91%-86%) were highly abundant, on the other hand expression of ABCG-2 and CD133 markers were 0.93% . In A549 cells, expression of CD29 marker was rare. Double positive CD29/44 and CD44/133 populations were rare, but double positive CD44/24 population exhibited a range from 18.60% to 79.4% in A549 cell line. Both double negative and positively CD44/24 and CD44+/24- sorted populations displayed similar clonogenic and spheres forming capacity. Conclusion: In this study, a panel of candidate CSC markers in A549 human lung adenocarcinoma epithelial cell line were assayed. Expression of ABCG-2, CD133 and CD29/44 and CD44/133 markers were very low. Consequently it was not possible to sort the cells using these markers. in vitro studies of both double negative and positively CD44/24 and CD44+/24- sorted populations suggested that CD44 and CD24 are not suitable markers for A549 lung cancer cell line, because these sorted CD44/24 populations showed similar clonogenic and sphere forming capacity. However this experiment needs to be complemented by and in vivo study for tumorogenicity of these populations in NOD-SCID mice.