The Autophage Activity Of Breast Cancer Cells Induced By IL-12 Through Akt Pathway

Objective:To investigate the effect and mechanism of rIL-12 on the autophage activity in human breast cancer cell MDA-MB-231 and MCF7 lines.Methods:The two lines of human breast cancer cell were treated with certain concentration rIL-12 for various time, or treated with various concentrations rIL-12 for constant time, LC3 protein was detected by Western blot assay. In order to show the autophagy acticity indirectly, LC3 protein expression in human breast cancer cells was detected by immunofluorescence. Transmission electron microscopy was used to view the autophagosome formation before or after the human breast cancer cells treated with rIL-12. Then, the Akt pathway was activated by IGF-1, which is the PI3K-Akt pathway activator. The whole-cell lysates were collected, and the changes of p-Akt /Akt proteins and LC3 protein were analyzed by Western blot.Results:The results of Western blot show that the expression of LC3 protein in the two human breast cancer cell lines treated by rIL-12 was upregulated significantly than that of the untreated group, and the ratio of protein LC3Ⅱ/β-actin was increased too. Further more, above effect of rIL-12 showed a time-and concentration-dependent stimulation manner. The immnofluorescence results revealed that the LC3 expression in breast cancer cells treated with rIL-12 was significantly increased compared to the untreated group. There were mach more green dot aggregate around the cell nucleus in the rIL-12 group and the positive control than that of untreated group. The autophagosome of human breast cancer cells treated with rIL-12 could be observed under the transmission electron microscopy. After the PI3K/Akt pathway was activated by IGF-1, the LC3 protein of IGF-1+rIL-12 group was decreased compared to the rIL-12 group.Conclusions:IL-12 can promote the autophagy activity of human breaset cancer cells and increase the LC3 protein expression through the PI3K/Akt-mTOR pathway.