Solute carrier family 12 member 5 promotes tumor invasion/metastasis of bladder urothelial carcinoma by enhancing NF-κB/MMP-7 signaling pathway.

Solute carrier family 12 member 5 (SLC12A5), an integral membrane KCl cotransporter, which maintains chloride homeostasis in neurons, is aberrantly expressed and involved in the tumorigenesis of certain cancers. However, the clinical significance and biological role of SLC12A5 in human bladder urothelial carcinoma (BUC) remains unclear. In this study, the expression of SLC12A5 was examined in clinical specimens of primary BUC and in BUC cell lines using quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR), western blot and immunohistochemistry (IHC). The prognostic value of SLC12A5 expression and its correlation with the clinicopathological features of patients with BUC were analyzed statistically. A series of in vitro and in vivo assays were performed to elucidate the effect of SLC12A5 in BUC and its underlying mechanisms. The present results showed that SLC12A5 expression was significantly increased in BUC tissues. SLC12A5 expression significantly correlated with the tumor node metastasis (TNM) stage. Kaplan-Meier survival curves showed that high SLC12A5 expression was associated with poor survival in patients with BUC. Multivariate analysis indicated that SLC12A5 expression was an independent prognostic marker for the survival of patients. Downregulation of SLC12A5 inhibited the migratory and invasive abilities of BUC cells in vitro, and knocking down SLC12A5 diminished BUC metastasis in vivo. Moreover, we identified that SLC12A5 promoted the migration and invasion of BUC by enhancing MMP-7 expression via NF-κB-dependent transcription. Taken together, our findings indicated that SLC12A5 might function as a tumor metastasis promoting factor in the development and progression of BUC by regulating the NF-κB/MMP-7 signaling pathway. Thus, SLC12A5 might be a prognostic marker as well as a therapeutic target for BUC.

EIF5A2 predicts outcome in localised invasive bladder cancer and promotes bladder cancer cell aggressiveness in vitro and in vivo.

BACKGROUND: EIF5A2, eukaryotic translation initiation factor 5A2, is associated with several human cancers. In this study, we investigated the role of EIF5A2 in the metastatic potential of localised invasive bladder cancer (BC) and its underlying molecular mechanisms were explored. METHODS: The expression pattern of EIF5A2 in localised invasive BC was determined by immunohistochemistry. In addition, the function of EIF5A2 in BC and its underlying mechanisms were elucidated with a series of in vitro and in vivo assays. RESULTS: Overexpression of EIF5A2 was an independent predictor for poor metastasis-free survival of localised invasive BC patients treated with radical cystectomy. Knockdown of EIF5A2 inhibited BC cell migratory and invasive capacities in vitro and metastatic potential in vivo and reversed epithelial-mesenchymal transition (EMT), whereas overexpression of EIF5A2 promoted BC cells motility and invasiveness in vitro and metastatic potential in vivo and induced EMT. In addition, we found that EIF5A2 might activate TGF-ß1 expression to induce EMT and drive aggressiveness in BC cells. EIF5A2 stabilized STAT3 and stimulated nuclear localisation of STAT3, which resulted in increasing enrichment of STAT3 onto TGF-ß1 promoter to enhance the transcription of TGF-ß1. CONCLUSIONS: EIF5A2 overexpression predicts tumour metastatic potential in patients with localised invasive BC treated with radical cystectomy. Furthermore, EIF5A2 elevated TGF-ß1 expression through STAT3 to induce EMT and promotes aggressiveness in BC.

AIB1 predicts bladder cancer outcome and promotes bladder cancer cell proliferation through AKT and E2F1.

BACKGROUND: We previously demonstrated that AIB1 overexpression is an independent molecular marker for shortened survival of bladder cancer (BC) patients. In this study, we characterised the role and molecular mechanisms of AIB1 in BC tumorigenicity. METHODS: AIB1 expression was measured by immunohistochemistry in non-muscle-invasive BC tissue and adjacent normal bladder tissue. In addition, the tumorigenicity of AIB1 was assessed with in vitro and in vivo functional assays. RESULTS: Overexpression of AIB1 was observed in tissues from 46 out of 146 patients with non-muscle-invasive BC and was an independent predictor for poor progression-free survival. Lentivirus-mediated AIB1 knockdown inhibited cell proliferation both in vitro and in vivo, whereas AIB1 overexpression promoted cell proliferation in vitro. The growth-inhibitory effect induced by AIB1 knockdown was mediated by G1 arrest, which was caused by reduced expression of key cell-cycle regulatory proteins through the AKT pathway and E2F1. CONCLUSION: Our results suggest that AIB1 promotes BC cell proliferation through the AKT pathway and E2F1. Furthermore, AIB1 overexpression predicts tumour progression in patients with non-muscle-invasive BC.

EZH2 supports nasopharyngeal carcinoma cell aggressiveness by forming a co-repressor complex with HDAC1/HDAC2 and Snail to inhibit E-cadherin.

The enhancer of zeste homolog 2 (EZH2) is upregulated and has an oncogenic role in several types of human cancer. However, the abnormalities of EZH2 and its underlying mechanisms in the pathogenesis of nasopharyngeal carcinoma (NPC) remain unknown. In this study, we found that high expression of EZH2 in NPC was associated closely with an aggressive and/or poor prognostic phenotype (P<0.05). In NPC cell lines, knockdown of EZH2 by short hairpin RNA was sufficient to inhibit cell invasiveness/metastasis both in vitro and in vivo, whereas ectopic overexpression of EZH2 supported NPC cell invasive capacity with a decreased expression of E-cadherin. In addition, ablation of endogenous Snail in NPC cells virtually totally prevented the repressive activity of EZH2 to E-cadherin, indicating that Snail might be a predominant mediator of EZH2 to suppress E-cadherin. Furthermore, co-immunoprecipitation (IP), chromatin IP and luciferase reporter assays demonstrated that in NPC cells, (1) EZH2 interacted with HDAC1/HDAC2 and Snail to form a repressive complex; (2) these components interact in a linear fashion, not in a triangular fashion, that is, HDAC1 or HDAC2 bridge the interaction between EZH2 and Snail; and (3) the EZH2/HDAC1/2/Snail complex could closely bind to the E-cadherin promoter by Snail, but not YY1, to repress E-cadherin. The data provided in this report suggest a critical role of EZH2 in the control of cell invasion and/or metastasis by forming a co-repressor complex with HDAC1/HDAC2/Snail to repress E-cadherin, an activity that might be responsible, at least in part, for the development and/or progression of human NPCs.