Icariin inhibits survival and metastasis of human non-small lung cancer A549 cells via activating CaMKII-JNK pathway

  Objective  To investigate inhibitive effect of icariin on survival and metastasis of human non-small cell lung cancer A549 cells via activating Ca²⁺/calmodulin-dependent protein kinase II (CaMKII) -c-Jun amino terminal kinase (JNK) pathway and the mechanisms of the effect.

  Methods  The A549 cells were administrated with icariin at different doses of 0, 0.10, 0.25, 0.50, 1.0, 2.5, 5.0, 10, 20, 50, 100, 200, 300 and 400 μmol for 24 hours. Then, the survival of the A549 cells was detected with Cell Counting Kit-8 (CCK8) and the invasion and migration capability the A549 cells were determined with Transwell assay and scratch assay. Immunofluorescence assay was used to measure vimentin expression. Western blot was adopted to detect expressions of vascular endothelial growth factor (VEGF), E-cadherin, N-cadherin, and the phosphorylation of Ca²⁺/calmodulin-dependent protein kinase II (CaMKII) and c-Jun amino terminal kinase (JNK) in the A549 cells treated with different concentrations (10, 20, 50 μmol) of icariin alone or combined with 10 μmol JNK inhibitor SP600125.

  Results  Significantly lower survival rates of 72 ± 8%, 57 ± 7%, 48 ± 6%, and 38 ± 5% were detected for the A549 cells treated with 100, 200, 300, and 400 μmol icariin compared to that for the cells without incariin treatment (all P < 0.01). Significantly decreased number of invasive cells (84 ± 12, 30 ± 8, 10 ± 5; all P < 0.01), rate of scratch healing (84 ± 7%,70 ± 6%, 45 ± 6%; all P < 0.01), and expressions of VEGF (0.40 ± 0.07, 0.16 ± 0.04, 0.05 ± 0.03), N-cadherin (0.70 ± 0.08, 0.26 ± 0.05, 0.08 ± 0.04) and vimentin (25.5 ± 2.9, 12.1 ± 2.6, 5.3 ± 2.0) (P < 0.05 for all) but significantly increased expression of E-cadherin (0.13 ± 0.05, 0.44 ± 0.06, 0.95 ± 0.08) and ratios of phosphorylated CaMKII/CaMKII (0.16 ± 0.05, 0.29 ± 0.07, 0.42 ± 0.07) and phosphorylated JNK/JNK (0.30 ± 0.06, 0.46 ± 0.08, 0.84 ± 0.09) (P < 0.05 for all) were detected in the A549 cells treated with 10, 20 and 50 μmol icariin in comparison with those detected in the cells without incariin treatment. In addition, 10 μmol icariin alleviated the inhibition of 10 μmol SP600125 on JNK phosphorylation in A549 cells.

  Conclusion  Icariin can up-regulate the phosphorylation of CaMKII and JNK and activate the pathway to inhibit the survival and metastasis of human non-small cell lung cancer A549 cells.