Roles Of Rab23in Cell Invasion, Migration And Proliferation Of Human Breast Cancer Cell Bcap-37

[Background]Breast cancer is one of the most common malignant tumors in female. Cell invasionand migration are the important factors influencing the progression of breast cancer.Rab23, a member of the Ras superfamily of small GTP enzymes, was first found in themouse of open brain phenotype. In addition to the involvement of development of brain,bones and limb, it also controls intracellular vesicle transport and promotes cell invasionand migration of liver and stomach tumors. In the previous study, we detected theexpression of Rab23in breast cancer cell lines MDA-MB-231, Bcap-37, MCF-7andnormal breast cell line HBL-100, and found that Rab23not merely inhibit breast cancercells proliferation but also reduce the activity of Hedgehog signaling pathway inMDA-MB-231, Bcap-37, MCF-7. However, it remains unclear whether Rab23isassociated with the cell invasion and metastasis of breast cancer. Therefore, this researchaimed at investigating the roles of Rab23in cell proliferation, invasion and migration ofbreast cancer, and providing new targets for prevention and treatment of breast cancer. [Objectives]1. To detect the expression of Rab23in breast cancer cell lines and normal breast cellline and establish stable breast cancer cells with Rab23high or low expression.2. To explore the effect of Rab23on cell invasion and migration of human breast cancercells Bcap-37in vitro and in vivo.3. To observe the effect of Rab23on cell proliferation of human breast cancer cellsBcap-37in vitro and in vivo.[Methods]1. Western blot was used to observe the expression of Rab23in normal breast cell lineHBL-100and breast cancer cell lines Bcap-37, MDA-MB-231, and MCF-7.2. Rab23/GV278and Rab23/GV248expression vector was constructed. The stableBcap-37cell lines of Rab23over-expression (Rab23/GV278-wide type) and silentexpression (Rab23/GV248-RNAi#1, Rab23/GV248-RNAi#2, Rab23/GV248-RNAi#3)was established by lentiviral transfection.3. Western blot was used to identify the expression of Gli1which was an essentialtranscription factor in Hedgehog signal pathway in breast cancer cell line Bcap-37ofover-expression or silence Rab23.4. The scratch-wound assay and the matrigel cell invasion assay were performed to testthe role of Rab23in the cell invasion of Bcap-37cells in vitro.5. The nude mice metastasis assay was performed to test the role of Rab23in themetastasis of Bcap-37cells in vivo.6. The effect of Rab23on proliferation of Bcap-37cells was measured by MTT assayand colony formation assay in vitro.7. The tumorigenicity was performed to test the role of Rab23in the proliferation ofBcap-37cells in vivo.[Results]1. Western blot showed that Rab23was expressed in all breast cancer cell lines andnormal breast cell line. Rab23expression was higher in Bcap-37cell than in other celllines, and it was of statistical significance compared with that in HBL-100(P<0.05). 2. Western blot confirmed successful establishment of stable Bcap-37cell lines of Rab23over-expression and silent expression.3. Western blot showed that over-expression of Rab23remarkably reduced theexpression of Gli1protein (P<0.05), while silence of Rab23expression significantlypromoted the expression of Gli1protein (P<0.05).4. The scratch-wound assay showed that over-expression of Rab23remarkably promotedthe migration of Bcap-37cells (P<0.01), compared with control cells, while silence ofRab23expression dramatically inhibited the migration of Bcap-37cells (P<0.05).5. The matrigel cell invasion assay showed that over-expression of Rab23remarkablypromoted the invasion of Bcap-37cells (P<0.01), while silence of Rab23expressionprominently inhibited the invasion of Bcap-37cells (P<0.01).6. The results of experimental metastasis assay showed that over-expression of Rab23signally promoted the metastasis of Bcap-37cells (P<0.01) and there were nometastasis case in Rab23-control cells and Rab23-silence cells.7. MTT assay showed that over-expression of Rab23markedly inhibited the proliferationof Bcap-37cells (P<0.01), while silence of Rab23expression notably promoted theproliferation of Bcap-37cells (P<0.01).8. The colony formation assay showed that over-expression of Rab23observably reducedthe number and size of Bcap-37cells (P<0.05), while silence of Rab23expressionnoticeably increased the number and size of Bcap-37cells (P<0.01).9. As the results of tumorigenicity assay showed, Bcap-37cell line could remarkablyinhibit proliferation by overexpression of Rab23(P<0.01), while significantly promoteby silence of Rab23(P<0.01).[Conclusions]1. Rab23is expressed in all breast cancer cell lines and normal breast cell line. Rab23expression was higher in Bcap-37cell than in others.2. In Bcap-37breast cancer cells Rab23can promote the miration motility andinvasiveness in vitro, but this effect of invasion and migration only in lung tissue butnot in hepatic in vivo. So, Rab23may have a positive effect in invasion and migration of Bcap-37.3. Rab23can inhibit the proliferation of Bcap-37cells either in vitro or in vivo.