Effect of IL-8 on mitochondrial fusion and fission gene expression in human lung adenocarcinoma cell line A549 during cell migration

AIM: To investigate the changes of migration of lung adenocarcinoma cells promoted by IL-8 and the inner and outer mitochondrial membrane dynamic changes during this process.METHODS: Human lung adenocarcinoma cell line A549 was divided into control group and IL-8 group. Cell migration was analyzed by scratch detection and Transwell assay. The secretion of endogenous IL-8 was detected by ELISA. The protein levels of mitochondrial cytochrome C (Cyt C) and mitochondrial outer membrane protein Tom20 was detected by Western blot. The mRNA expression of mitochondrial fusion genes Mfn1, Mfn2 and OPA1 and fission genes Fis1, Drp1 and MTP18 was detected by RT-PCR. The morphological changes of mitochondria were observed by MitoTracker Red CMXRos dye staining and confocal microscopy.RESULTS: The migratory rate of A549 cells and endogenous secretion of IL-8 in A549 cells were higher than those in SPC-A-1 cells. The migratory rate of A549 cells was improved by IL-8 in a time-dependent manner. Compared with control group, the Tom20 protein expression was increased (P<0.05), and the Cyt C protein expression was decreased (P<0.05). The expression of mitochondrial outer membrane fusion genes Mfn1 and Mfn2 was increased (P<0.05), and the expression of mitochondrial inner membrane fusion gene OPA1 was decreased (P<0.05). The expression of fission genes Drp1 and MTP18 were decreased (P<0.05), while the expression of Fis1 was no change (P>0.05). Under confocal microscope, the punctate aggregates in the mitochondria of the A549 cells treated with IL-8 were observed.CONCLUSION: The migratory rate of A549 cells is increased by IL-8, which is related to the changes of mitochondrial fusion genes and the fission genes.