['To study the chemosensitivity of lung adenocarcinoma cell line A549 cells to liposome-encapsulated paclitaxel after treatment by nm23-H1-small interference RNA (nm23-H1-siRNA) in vitro.', 'The A549 cells were divided into two groups: non-transfected group and nm23-H1-siRNA-transfected group. Western blot analysis was used to detect the expression of nm23-H1. MTT and flow cytometry were used to determine the cell mortality rate, apoptosis rate and cell cycle after liposome-encapsulated paclitaxel treatment in both groups.', 'The expression of nm23-H1 in A549 cells was significantly decreased after transfection with nm23-H1-siRNA. After treatment for 48 hours with liposome-encapsulated paclitaxel, the cell mortality rate was increased with the increasing concentration of liposome-encapsulated paclitaxel in both groups, but increased higher in the nm23-H1-siRNA-transfected group. When the concentration of liposome-encapsulated paclitaxel was above 5 µg/ml, the cell mortality rate was significantly higher than that in the non-transfected group (P < 0.05). The proportion of apoptotic cells also increased in the nm23-H1-siRNA-transfected group, compared with that of the non-transfected group (t = 3.812, P < 0.05), while the proportion of cells at S and G(2)/M phase decreased after transfection with nm23-H1-siRNA (S phase:t = 8.356, P < 0.05; G(2)/M phase:t = 7.256, P < 0.05).'] Does [ nm23-H1-siRNA enhance the chemosensitivity to liposome-encapsulated paclitaxel in lung adenocarcinoma cells in vitro ]?