Yangyin Huayu Jiedu Preseription Regulates Autophagy and Apoptosis of Colon Cancer Cells in Hypoxic Environment Through PI3K/Akt Signaling Pathway / 中国实验方剂学杂志

ABSTRACT

ObjectiveTo investigate the effect of different oxygen concentration on the proliferation and autophagy of colon cancer cells and to explore the effect of Yangyin Huayu Jiedu Preseription （YHJP） on autophagy and apoptosis of colon cancer cells under hypoxia based on phosphatidylinositol 3-kinase/protein kinase B （PI3K/Akt） signaling pathway. MethodHCT-116 cells were divided into normoxia group， 1% O2 group， and 5% O2 group. Cell viability was detected by cell proliferation assay （MTS）， and autophagy was observed based on monodansylcadaverine （MDC） staining. HCT-116 cells were treated with YHJP in 5% O2 microenvironment. The cells were divided into normal group， blank serum group， and low-， medium-， high-dose YHJP groups （5%， 15%， 25% serum containing YHJP）. Cell inhibition rate in each group was calculated by MTS， and changes in the rate of autophagy were detected based on MDC staining. Annexin V-fluorescein isothiocyanate （FITC）/propidium iodide （PI） was employed to detect the apoptosis rate of each group. Western blotting was applied to measure the expression of autophagy proteins microtubule-associated protein 1 light chain 3 （LC3Ⅱ/Ⅰ）， yeast Atg6 homolog （Beclin-1）， ubiquitin-binding scaffold protein p62 （p62）， apoptosis-related proteins B-cell lymphoma-2 （Bcl-2）， Bcl-2/adenovirus E1B interacting protein 3 （BNIP-3）， and Bcl-2 associated X protein （Bax）， cleaved cysteine-aspartic acid protease-3 （Caspase-3）， hypoxia-inducible factor-1α （HIF-1α） and pathway proteins PI3K， phosphorylated （p）-PI3K， Akt， and p-Akt. ResultCell survival rates of the 1% O2 and 5% O2 groups were increased compared with that in the normoxia group， particularly the 5% O2 group （P<0.01）. The fluorescence intensity for autophagy in 1% O2 and 5% O2 groups was significantly increased compared with that in the normoxia group， especially the 5% O2 group. In the presence of 5% O2， compared with the blank serum group， medium-dose and high-dose YHJP groups showed high cell inhibition rate， low autophagy rate， high apoptosis rate （P<0.01）， and low expression of Beclin-1 protein （P<0.05）. Compared with low-dose YHJP group， high-dose YHJP group demonstrated low expression of Beclin-1 protein （P<0.05）. Compared with the blank serum group， the three YHJP groups had low expression of LC3Ⅱ/Ⅰ protein （P<0.05， P<0.01）. Compared with the blank serum group， medium-dose and high-dose YHJP groups showed high expression of p62 protein （P<0.01）. Compared with low-dose YHJP group， high-dose YHJP group showed high expression of p62 protein （P<0.05）. Compared with the blank serum group， high-dose YHJP increased the expression of BNIP-3 and Bax and decreased the expression of Bcl-2 （P<0.01）. The expression of Bax protein in the high-dose YHJP group was increased compared with that in the low-dose YHJP group （P<0.05）. The expression of HIF-1α in the medium-dose and high-dose YHJP groups was decreased （P<0.01） and the expression of p-PI3K/PI3K and p-Akt/Akt in the high-dose YHJP group was increased （P<0.05， P<0.01） compared with that in the blank serum group. The expression of p-Akt/Akt was higher in the high-dose YHJP group than in the medium-dose YHJP （P<0.05）. ConclusionHypoxic microenvironment can significantly promote autophagy and proliferation of colon cancer cells. YHJP can significantly inhibit autophagy and proliferation and promote apoptosis of colon cancer cells in 5% O2 environment by up-regulating the PI3K/Akt signaling pathway.