Abstract: Objective To investigate whether chlorogenic acid can inhibit the proliferation， migration， invasion and promote apoptosis of lung cancer A549 cells by causing mitochondrial dysfunction through PI3K-Akt pathway. Methods A549 cells were treated with chlorogenic acid at concentrations of 0， 25， 50， 100， 150， and 200 μg/ml for 48 h. CCK-8 assay was used to detect the cell proliferation rate and calculate the half maximal inhibitory concentration （IC₅₀）. A549 cells were divided into three groups： control group， chlorogenic acid group （IC₅₀） and chlorogenic acid + 740-YP group （IC₅₀ chlorogenic acid +50 μg/ml 740YP）. After 48 h of intervention， the cell migration distance was detected by cell scratch assay. Cell invasion assay was used to detect cell invasion ability. Cell cycle， apoptosis and mitochondrial membrane potential were detected by flow cytometry. The content of malondialdehyde （MDA） in cell supernatant was detected by enzyme-linked immunosorbent assay （ELISA）. Western blotting was used to detect the protein expression of p-PI3K， p-Akt and Caspase3. Results The IC₅₀ of chlorogenic acid to A549 cells was 57.45 μg/ml. The results of cell scratch assay showed that the 48 h migration distances of the control group， chlorogenic acid group and chlorogenic acid + 740YP group were （424.80±14.43）， （289.67±18.93） and （402.22±17.99） μm， respectively. The results of cell invasion assay showed that the numbers of invasive cells after 48 h were 96.00±6.24， 35.33±7.64 and 83.00±2.00， and the results of flow cytometry showed that the 48 h apoptosis rates were （6.15±0.17）%， （54.63±0.72）% and （17.27±0.39）%， respectively， among the three groups with statistically significant differences （F=105.98， P<0.001； F=90.62， P<0.001； F=8 321.99， P<0.001）. Compared with the control group， the cell migration distances and invasive numbers of chlorogenic acid group and chlorogenic acid + 740YP group were decreased （all P<0.05）， while the apoptosis rates were significantly increased （both P<0.001）. Compared with chlorogenic acid group， the cell migration distance of chlorogenic acid + 740YP group increased （P<0.001）， the number of cell invasion increased （P<0.001）， and the apoptosis rate decreased （P<0.001）. The results of flow cytometry showed that the proportions of cells in G₀/G₁ phase in the control group， chlorogenic acid group and chlorogenic acid + 740YP group were （65.75±0.58）%， （55.84±0.78）% and （55.24±1.37）%， respectively. The proportions of G₂/M phase were （11.21±1.03）%， （20.23±0.62）% and （9.96±0.33）%， and the proportions of S phase were （23.04±0.49）%， （23.92±1.36）% and （34.80±1.15）%， respectively， with statistically significant differences （F=111.02， P<0.001； F=181.26， P<0.001； F=113.05， P<0.001）. Compared with the control group， the proportions of G₀/G₁ phase cells in chlorogenic acid group and chlorogenic acid + 740YP group decreased （both P<0.001）， and the proportion of G₂/M phase in chlorogenic acid group increased （P<0.001）， and the proportion of S phase cells in chlorogenic acid + 740YP group increased （P<0.001）. Compared with chlorogenic acid group， the proportion of G₂/M phase cells decreased and the proportion of S phase cells increased in chlorogenic acid + 740YP group （both P<0.001）. The results of mitochondrial membrane potential detection showed that the JC-1 fluorescence intensity of mitochondria in the control group， chlorogenic acid group and chlorogenic acid + 740YP group were 39.51±1.32， 10.05±0.19 and 21.85±1.45， respectively， with a statistically significant difference （F=508.82， P<0.001）. Compared with the control group， the fluorescence intensity of chlorogenic acid group and chlorogenic acid + 740YP group decreased （both P<0.001）. Compared with chlorogenic acid group， the fluorescence intensity of chlorogenic acid + 740YP group increased （P<0.001）. ELISA results showed that the MDA contents of the control group， chlorogenic acid group and chlorogenic acid + 740YP group were （0.47±0.01）， （0.61±0.01） and （0.56±0.01） nmol/ml， respectively， with a statistically significant difference （F=162.30， P<0.001）. Compared with the control group， MDA contents in chlorogenic acid group and chlorogenic acid + 740YP group increased （both P<0.001）. Compared with chlorogenic acid group， MDA content in chlorogenic acid + 740YP group decreased （P=0.001）. Western blotting results showed that the relative protein expression levels of p-PI3K in the control group， chlorogenic acid group and chlorogenic acid + 740YP group were 1.01±0.33， 0.28±0.14 and 0.34±0.20， respectively. The relative protein expression levels of p-Akt were 1.00±0.16， 0.43±0.05 and 0.95±0.14， and the relative protein expression levels of Caspase3 were 1.00±0.04， 1.41±0.05 and 0.70±0.13， respectively， and there were statistically significant differences （F=8.48， P=0.018； F=19.11， P=0.002； F=57.50， P<0.001）. Compared with the control group， the expressions of p-PI3K and p-Akt protein in chlorogenic acid group decreased， and the expression of Caspase3 protein increased （all P<0.05）. The expressions of p-PI3K and Caspase3 protein in chlorogenic acid + 740YP group decreased （both P<0.05）. Compared with chlorogenic acid group， the expression of p-Akt protein in chlorogenic acid + 740YP group increased， and the expression of Caspase3 protein decreased （both P<0.05）. Conclusion Chlorogenic acid may inhibit the PI3K-Akt pathway by reducing the phosphorylation of PI3K and Akt proteins， resulting in the damage of mitochondrial function and the accumulation of MDA， which eventually leads to the damage of lung cancer A549 cells function and the reduction of cells activity， and then promotes cells apoptosis.

Key words: Carcinoma， non-small-cell lung, Chlorogenic acid, Phosphatidylinositol 3-kinases, Apoptosis, Mitochondria