Down-regulation of ALDH1A1 increased expression of carcinogenesis-related genes in non-small cell lung cancer cell line of A549

Purpose: This study was aimed to isolate the putative cancer stem cell (CSC) populations from A549 lung cancer cell line and to evaluate the difference of carcinogenesis-related genes expression within parental population (A549) and isolated CSC populations (A549 CD166+ /EpCAM+ and CD166+ /CD44+). Methods: We performed flow cytometry analysis to sort out cell positive for these markers; CD166+ /EpCAM + and CD166+ /CD44+ from A549 cancer cell line. The isolated cells were tested for multipotent capacities by clonogenic and differentiation assays. Quantitative real time PCR was performed for both isolated CSC population and parental population to test expression of ALDH1A1 and 6 other genes that known to contribute to carcinogenesis; RARβ CYP24A1, BIRC5, EDN1, IL1β and PTGS2. Result(s): Both CD166+ /EpCAM+ and CD166+ /CD44+ have ability to form colonies and able to differentiate into adipocytes and osteocyte. Expression of ALDH1A1 was downregulated in all three cell populations (parental A549, A549 CD166+ /EpCAM+ and A549 CD166+ /CD44+) whereas the other 6 carcinogenesis-related genes were upregulated in all three cancer cell populations. There are no significant differences of gene expressions were detected among all three populations (p > 0.05). Conclusion(s): Downregulation of ALDH1A1 in all three cancer populations up-regulate the expression of other 6 carcinogenesis-related genes. Gene regulations between parental cancer cell (A549) and both putative CSC populations show no significant difference suggesting the existence of various CSC subpopulations reside within parental A549 population.