EFFECT OF REGULATOR OF RIBOSOME SYNTHESIS 1 ON THE PROLIFERATION AND MIGRATION OF BREAST CANCER CELLS AND ITS MECHANISM OF ACTION

Abstract

Objective To investigate the effect of the regulator of ribosome synthesis 1 (RRS1) gene on the proliferation and migration of breast cancer BT549 cells and its mechanism of action. Methods Western blot was used to measure the protein expression of RRS1 in human breast cancer cell lines (MDA-MB-231, MDA-MB-468, BT549, and MCF-7 cells) and normal human breast epithelial MCF-10A cells, and immunofluorescence assay was used to observe the localization of RRS1 in BT549 cells. The lentivirus infection method was used to establish an RRS1-knockdown BT549 cell line, and quantitative real-time PCR and Western blot were used to measure the relative mRNA and protein expression levels of RRS1 in the Con group transfected with negative control lentivirus and the sh-RRS1 group transfected with shRNA-RRS1 lentivirus. CCK8 assay and colony-forming assay were used to observe the effect of RRS1 on the proliferation ability of BT549 cells, and wound healing assay and Transwell assay were used to observe the effect of RRS1 on the migration ability of BT549 cells. Western blot was used to measure the relative expression levels of AKT-mTOR signaling pathway proteins and their downstream proteins hypoxia-inducible factor 1α (HIF-1α) and vascular endothelial growth factor (VEGF) in the two groups. Results The relative expression level of RRS1 in breast cancer cell lines MDA-MB-231, MDA-MB-468, BT549, and MCF-7 was significantly higher than that in normal human breast epithelial MCF-10A cells (F=48.92,P<0.05). Immunofluorescent staining showed that RRS1 was mainly expressed in the nucleus and nucleolus of BT549 cells, with a low expression level in the cytoplasm. Compared with the Con group, the sh-RRS1 group had significant reductions in the mRNA and protein expression levels of RRS1, the proliferation and migration abilities of cells, and the protein expression le-vels of p-AKT, p-mTOR, HIF-1α, and VEGF (t=6.29-32.04,F=1 368.00,2 699.00,P<0.05). Conclusion RRS1 may promote the proliferation and migration of breast cancer cells through the AKT-mTOR pathway.

Keywords

• breast neoplasms|regulator of ribosome synthesis 1|cell line, tumor|gene expression regulation|cell movement|cell proliferation