Effect of Qingzao Jiufeitang on Protein Expression Related to Autophagy Initiation in Lung Cancer Cells Through AMPK inhibition / 中国实验方剂学杂志

ABSTRACT

ObjectiveTo observe the effects of Qingzao Jiufeitang on the expression of adenosine 5′-monophosphate （AMP）-activated protein kinase （AMPK）， mammalian target of rapamycin （mTOR）， and UNC-51-like kinase 1 （ULK1） in lung cancer cells after the application of AMPK inhibitor （compound C）. MethodMale C57BL/6J mice were randomly divided into a model group， a cyclophosphamide （CTX） group （50 mg·kg-1）， a Qingzao Jiufeitang group （11 g·kg-1）， an AMPK inhibitor group （10 mg·kg-1）， and a Qingzao Jiufeitang combined with AMPK inhibitor group （combination group） （11 g·kg-1+10 mg·kg-1）. Lewis lung cancer cells were subcutaneously injected into the right axilla to induce a tumor-bearing model. 24 hours after modeling， the mice in the CTX group were intraperitoneally injected once every other day for seven times in total. The mice in the AMPK inhibitor group and the combination group received intraperitoneal injection of compound C， once a day for 14 days. The mice in the Qingzao Jiufeitang group and the combination group were administered orally at the set dose for 14 days before and after modeling. At the end of the experiment， the mice in each group were sacrificed. The tumor-bearing tissues were collected， and the tumor weight of each group was counted. Transmission electron microscopy （TEM） was used to observe the formation of autolysosomes in lung cancer tissues of each group. Western blot was used to detect the protein expression of AMPK， phosphorylated AMPK （p-AMPK）， mTOR， phosphorylated mTOR （p-mTOR）， ULK1， phosphorylated ULK1 （p-ULK1）， microtubule-associated protein 1 light chain 3B （LC3B）， and p62. Hematoxylin-eosin （HE） staining was used to observe the pathological changes of lung cancer in each group. ResultCompared with the model group， the Qingzao Jiufeitang group showed decreased tumor weight （P<0.01）， the formation of autolysosomes under the electron microscope， increased protein expression of p-AMPK， p-ULK1， LC3B， LC3B-Ⅱ， and p-AMPK/AMPK， p-ULK1/ULK1， and LC3B-Ⅱ/LC3B-Ⅰratios （P<0.01， P<0.05）， and reduced protein expression of p-mTOR， p62， and p-mTOR/mTOR ratio （P<0.05）. Compared with the Qingzao Jiufeitang group， the combination group showed no autolysosomes formation under the electron microscope， decreased protein expression of p-AMPK， p-ULK1， LC3B， LC3B-Ⅱ， and p-AMPK/AMPK， p-ULK1/ULK1， LC3B-Ⅱ/LC3B-Ⅰ ratios （P<0.05， P<0.01）， and increased p62 protein expression （P<0.05）. HE staining results showed that the pathological changes of lung cancer tissues in the groups with drug intervention were improved compared with those in the model group. ConclusionQingzao Jiufeitang can promote the elevation of LC3B-Ⅱ and decrease the expression of p62 protein， thus inducing autophagy. The mechanism of autophagy initiation may be achieved by the AMPK/ULK1 pathway instead of the mediation by the AMPK/mTOR/ULK1 pathway.