Abstract:

Objective To investigate the effect of ribosomal protein S6 kinase 4 variants 1 （RSK4m1） on the proliferation and invasion by human breast cancer cell line MDA-MB-231． Methods RSK4m1 was stably overexpressed in human breast cancer cell line MDA-MB-231 using lentivirus encoding RSK4m1. Untreated MDA-MB-231 cells served as a blank control group，MDA-MB-231 cells transfected with empty virus served as a negative control group and MDA-MB-231 cells transfected with the RSK4m1 overexpression cassette served as the experimental group. The expression of RSK4m1 in each group was detected by real-time PCR and Western blot analysis. The proliferation of cells was assayed using the cell counting kit-8 （CCK-8），and cell migration was measured using the wound healing test. Invasion was detected using the Transwell test. Results The mRNA and protein expression of RSK4m1 was significantly up-regulated in the experimental group（P<0.05）. The CCK-8 assay showed that the proliferation of the experimental group was significantly lower than that of the negative control group and blank control group at 24，48，72 and 96 h（P<0.05）. The wound healing test showed that the closure rate of the cells in the experimental group was significantly lower than that in the blank control group and the negative control group after 24 h of cell culture（P<0.05）. The transwell test showed that the invasive ability of the experimental group was significantly lower than that in the blank control group and the negative control group （P<0.05）. Conclusions Overexpression of RSK4 variant 1 can effectively suppress cell proliferation，migration and invasion by MDA-MB-231 cells，which provides an experimental basis for researching RSK4 variant 1 as a new target in the treatment of human breast cancer.

Key words: Breast neoplasms, Human breast cell lines, Ribosomal protein S6 kinase 4 variants 1, Cell proliferation, Cell invasion, Cell migration