Expression and significance of EGFR and ADAM9 in pancreatic cancer stem cells and differentiated cells

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Objective To enrich pancreatic cancer stem cells through culturing mammospheres, and to detect the expressions of epidermal growth factor receptor(EGFR) and a disintegrin and metalloprotease 9 (ADAM9) and investigate their significance. Methods PANC1 cells were cultured in serum-free conditioned medium to continuously generate mammospheres, and parts of mammospheres were cultured on a collagen substratum to induce differentiation. Mammospheres cells and differentiated cells were collected, flow cytometry was used to detect the proportion of side population (SP) cells, and the expressions of EGFR, ADAM9 mRNA and protein were detected by real-time PCR and Western blotting. Results PANC1 cells mammospheres were successfully generated and could be passed continuously. After differentiation, mammospheres cells could regain the ability of adherent growth. The proportion SP cells in mammospheres cells and differentiated cells were ( 5.40 ± 0.38 ) % and (2.80 ± 0.42 ) %, and the difference was statistically significant ( P ＜ 0. 05 ).Compared with differentiated cells, the expression of EGFR and ADAM9 mRNA of mammospheres cells upregulated 2.5 and 3.0 folds ( P ＜ 0. 05 ). The expressions of EGFR and ADAM9 protein of mammospheres cells were 0.90 ± 0. 09 and 0.64 ± 0.07, which were significantly higher than those in differentiated cells (0.62 ±0.11 and 0.48 ±0.09, P ＜0.05). Conclusions Mammosphere cells contained higher proportion of pancreatic cancer stem cells. ADAM 9 may play an important role in the occurrence and development of pancreatic cancer through the EGFR signaling pathway. Key words: Pancreatic neoplasms; Stem cells; Receptor, epidermal grouth factor; A disintegrin and metalloprotease