RESUMO
OBJECTIVE To investigate the inhibitory effects of ursolic acid on interleukin-6 （IL-6）-mediated invasion and migration of breast cancer MDA-MB-231 cells （hereinafter referred to as “231 cells”）. METHODS The effects of 20， 40， 80， 160 and 320 µmol/L ursolic acid on the proliferation rate of 231 cells were measured by CCK-8 method. The breast cancer 231 cells were divided into control group， model group and administration group. The migration and invasion abilities of cells were detected by scratch assay and Transwell assay. Real-time quantitative polymerase chain reaction （q-PCR） assay and Western blot assay were used to detect the mRNA and protein expressions of epithelial-mesenchymal transition-related makers such as E cadherin （E-cad）， matrix metalloprotein 2 （MMP2）， MMP9， vimentin （Vim）， CD44 molecule （CD44） and aldehyde dehydrogenase 1 family member A1 （ALDH1A1）. The phosphorylation levels of JAK2 and STAT3 in the Janus kinase 2/signal transducer and activator of transcription 3 （JAK2/STAT3） signaling pathway （in terms of p-JAK2/JAK2 ratio and p-STAT3/STAT3 ratio） were detected by Western blot assay. RESULTS A low concentration of ursolic acid of 20 µmol/L （no significant inhibitory effect on cell proliferation ability） was selected as the subsequent administration concentration. Compared with the control group， the migration and invasion abilities of cells in the model group were significantly enhanced （P＜0.05）； compared with the model group， the migration and invasion abilities of cells in the administered group were significantly reduced （P＜0.05）. Compared with the control group， the relative mRNA and protein expressions of epithelial-mesenchymal transition-related markers MMP9， MMP2， Vim， ALDH1A1 and CD44 were all elevated to different extents， and the mRNA and protein expressions of E-cad were all decreased to different extents in the model group cells， and part of the differences had statistical significance （P＜0.05）， the p-JAK2/JAK2 ratio and p-STAT3/STAT3 ratio were significantly increased in the model group （P＜0.05）； compared with the model group， the expressions of the above indicators were reversed to some extent in the administration group. CONCLUSIONS Ursolic acid blocks the activation of JAK2/STAT3 signaling pathwby the inflammatory factor IL-6， which ultimately interrupts the invasion and metastasis of breast cancer cells.
RESUMO
Myeloid differentiation factor 88 (MyD88) plays an important role in tumorigenesis,development and malignant transformation,also participates in the microenvironment,proliferation,apoptosis,invasion,metastasis and tumor resistance.MyD88 may serve as a new and meaningful therapeutic target,which can promote the growth and development of tumors by regulating multiple signaling pathways and enhance the drug resistance of tumor cells.