XB-ART-55488Biochem Biophys Res Commun January 1, 2018; 507 (1-4): 74-82.
Targeting TPX2 suppresses proliferation and promotes apoptosis via repression of the PI3k/AKT/P21 signaling pathway and activation of p53 pathway in breast cancer.
Targeting protein for Xenopus kinesin-like protein 2 (TPX2) is a microtubule-associated protein required for mitosis and spindle assembly. Previous studies showed that TPX2 is overexpressed in various human cancers and promotes cancer progression. In this study, the differentially expressed genes including TPX2 were screened in GEO database for gene expression microarray of breast cancer. The TPX2 expression level was significantly increased in breast cancer cells and the breast malignant tissues compared with those controls. In vitro experiment further confirmed that knockdown of TPX2 by small hairpin RNA inhibited breast cancer cell proliferatio, migration, and induced cell apoptosis. TPX2 silencing decreased the expression of PI3K and extent of AKT phosphorylation, as well as increased expression of p53 and p21. Taken together, our findings indicate that TPX2 silencing negatively regulates the PI3K/AKT and activates p53 signaling pathway by which breast cancer cells proliferation were inhibited whereas cellulars apoptosis were accelerated, suggesting that TPX2 may be a potential target for anticancer therapy in breast cancer.
PubMed ID: 30454896
Article link: Biochem Biophys Res Commun
Species referenced: Xenopus
Genes referenced: akt1 bax cdkn1a mdm2 pik3ca pik3cg tp53 tpx2
Disease Ontology terms: breast cancer
Article Images: [+] show captions
|Fig. 2. TPX2 inhibition suppressed proliferation and induced apoptosis of breast cancer cells. A. TPX2 knockdown efficiency was determined by Western blot and qRT-PCR analysis in MCF-7 and T47D cells; B. Suppression of TPX2 significantly reduced the proliferation of MCF-7 and T47D cells; C. MCF-7 and T47D cells were transfected with shCtrl and shTPX2-1/2 for the clonogenic assay. Representative data and quantitative results are shown; D. Representative images showed the migration ability of MCF-7 and T47D cells transfected with shTPX2-2 or shCtrl (original magnification ×200) and quantitative results were shown; E. The percentage of apoptosis were measured by flow cytometry in the transduced MCF-7 and T47D cells. All experiments were carried out in triplicate. Data are shown as mean ± SEM, *P <0.05, **P <0.01.|
|Fig. 4. Suppression of TPX2 activated p53 pathway. A. The protein expression of MDM2 and P53 in MCF-7 and T47D cells, treated with shTPX2-1/2 and shCtrl, were analyzed by western blot. B. Immunofluorescence analysis revealed that p53 was considerably higher in TPX2 knockdown MCF-7 and T47D cells compared with controls. TPX2 mainly located in spindle during mitosis and expressed in the nucleus during other phase. In shTPX2-1/2 transfected breast cancer cells, p53 mainly located at nucleolus. The DAPI nuclear staining was shown in blue, TPX2 expression in red and p53 in green. C. Western blot analysis of co-immunoprecipitated ability of TPX2, p53 and MDM2 with each other in MCF-7 cells. D. Schematic model of TPX2 regulates AKT signaling pathway and p53 pathway in breast cancer. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)|