Ott_a_233129 3783..3794

1Department of Pathology, Science and Education Department of the Fifth People’s Hospital of Qinghai, Xining, Qinhai, 810000, People’s Republic of China; 2Department of Pediatrics, The Fifth Affiliated Hospital of Harbin Medical University, Daqing, Heilongjiang, 163319, People’s Republic of China; 3Department of Nuclear Medicine, The Fifth People’s Hospital of Qinghai, Xining, Qinhai, 810000, People’s Republic of China; 4Department of Physiology, College of Life Science and Biopharmaceutics of Shenyang Pharmaceutical University, Shenyang, Liaoning, 110001, People’s Republic of China; 5Department of Pathology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, 110001, People’s Republic of China Background: The influence of 5-fluorouracil (5-Fu) and cisplatin (CDDP) on the A549 and NCI-H226 cells was studied, and the epigenetic mechanism of enrichment of A549 lung cancer stem cells with 5-Fu was explored. Materials and Methods: The cell proliferation of both A549 and NCI-H226 was detected by BrdU assay, and apoptosis condition was measured by flow cytometric analysis. The expressions of OCT3/4 and Nanog in cells treated with 5-Fu or CDDP were measured by immunofluorescence, Western blot and qPCR. qPCR was also performed to determine the relative expression of methyltransferase genes and miRNA. Sequencing after bisulfite treatment (BSP) was employed to detect the methylation of OCT3/4 promoter in A549 cells. And ChIP was conducted to detect the expression of H3K9Me3 and H3K9Ace. Results: Both 5-Fu and CDDP result in the apoptosis of A549 and NCI-H226 cells and improve the expressions of has-miR-134 and has-miR-296. However, 5-Fu enhances the expression of OCT3/4 in A549 cells, and the change of methyltransferase genes and BSP results suggested some genetic differences between CDDP and 5-Fu treatment in A549 cells. ChIP assay showed that the expression of H3K9Me3 significantly decreased and H3K9Ace significantly increased in A549 cells. Conclusion: The enrichment effect of CDDP on A549 and NCI-H226 carcinoma stem cells is inconsistent with the enrichment effect of 5-Fu. The enrichment of A549 lung cancer stem cells with 5-Fu might be related to the methylation of OCT3/4 promoter and the expression of H3K9Me3 and H3K9Ace.