Abstract
Background: KIAA1456 is effective in the inhibition of tumorigenesis. We previously confirmed that KIAA1456 inhibits cell proliferation and metastasis in epithelial ovarian tumours. In the current study, the specific molecular mechanisms and clinical significance of KIAA1456 underlying the repression of epithelial ovarian cancer were investigated.Methods: Immunohistochemistry was used to evaluate the protein expression of KIAA1456 and SSX1 in epithelial ovarian tumours and normal ovarian tissues. The relationship of KIAA1456 and SSX1 with overall survival of patients with epithelial ovarian cancer was analysed with Kaplan–Meier survival curve and log-rank tests. KIAA1456 was overexpressed and silenced in HO8910PM cells with a lentivirus. The anticancer activity of KIAA1456 was tested by CCK8, plate clone formation assay, flow cytometry, wound healing assay and Transwell invasion assay. Xenograft tumour models were used to investigate the effects of KIAA1456 on tumour growth in vivo. Bioinformatics analyses of microarray profiling indicated that SSX1 and the PI3K/AKT signalling pathway were differentially expressed in KIAA1456-overexpressing and control cells. Therefore, the biological function of HO8910PM cotransfected with KIAA1456- and SSX1-overexpressing cells was detected to validate the rescue effect of SSX1. The downstream factors of PI3K/AKT that are related to cell growth and apoptosis, including p-AKT, PCNA, MMP9, CyclinD1 and Bcl-2, were detected by Western blot analysis.Results: KIAA1456 expression was lower in epithelial ovarian tumours than in normal ovarian tissues. Its expression level negatively correlated with pathological grade. Pearson’s correlation analysis showed that KIAA1456 negatively correlated with SSX1 expression. The overexpression of KIAA1456 in HO8910PM cells inhibited proliferation, migration and invasion and promoted apoptosis. By contrast, the silencing of KIAA1456 resulted in the opposite behaviour. A xenograft tumour experiment showed that KIAA1456 overexpression inhibited tumour growth in vivo. Mechanistically, the overexpression of KIAA1456 inhibited SSX1 expression and AKT phosphorylation in HO8910PM cells, causing the inactivation of the AKT signalling pathway and eventually reducing the expression of PCNA, CyclinD1, MMP9 and Bcl2. Similarly, the silencing of KIAA1456 resulted in the opposite behaviour. Finally, SSX1 overexpression could partially reverse the KIAA1456-induced biological effect.Conclusion: KIAA1456 may serve as a tumour suppressor via the inactivation of SSX1 and the AKT pathway, providing a promising therapeutic target for epithelial ovarian cancers.
Paediatric ovarian tumours and their associated cancer susceptibility syndromes
