UPK1B promotes the invasion and metastasis of bladder cancer via regulating the Wnt/ß-catenin pathway.

OBJECTIVE: The aim of this study was to investigate the expression of UPK1B in bladder cancer (BCa), and to further explore the correlation between UPK1B expression and pathological parameters as well as the prognosis of BCa. PATIENTS AND METHODS: Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the expression of UPK1B in 92 pairs of BCa tissues and adjacent normal tissues. The relationship between UPK1B expression and pathological features as well as the prognosis of BCa patients was further analyzed. For in vitro experiments, the mRNA expression level of UPK1B in BCa cell lines (EJ and T-24) was detected by qRT-PCR. In addition, knockdown of UPK1B in BCa cells was constructed using small interfering RNA. Effects of UPK1B knockdown on biological functions of BCa cells were analyzed by Cell Counting Kit-8 (CCK-8), colony formation assay and transwell assay, respectively. Furthermore, the underlying mechanism of UPK1B in regulating BCa was evaluated by Western blot and qRT-PCR, respectively. RESULTS: The expression of UPK1B in BCa tissues was remarkably higher than that of adjacent normal tissues (p<0.05). Compared with BCa patients with lower UPK1B expression, those with higher UPK1B expression exhibited higher tumor stage, lymph node metastasis and distant metastasis. In vitro experiments indicated that cell proliferation, invasion and metastasis were remarkably decreased in cells transfected with si-UPK1B when compared with those transfected with negative controls. Western blot showed that the expression of key proteins in the Wnt/ß-catenin signaling pathway in cells transfected with si-UPK1B was significantly down-regulated compared with those transfected with negative controls, including ß-catenin, c-myc and cyclinD1. In addition, rescue experiments found that UPK1B was regulated by ß-catenin. CONCLUSIONS: UPK1B is upregulated in BCa, and is significantly correlated with tumor stage, lymph node metastasis, distant metastasis and poor prognosis of BCa. Moreover, UPK1B promotes the proliferation, invasion and migration of BCa via regulating the Wnt/ß-catenin signaling pathway.

Production of human tetraspanin proteins in Escherichia coli.

Tetraspanins are found in multicellular eukaryotes and are generally thought to act as scaffolding proteins, localizing multiple proteins to a specific region of the cell membrane. Activities for tetraspanins have been identified in several fundamental processes such as motility, cell adhesion, proliferation and viral entry. Tetraspanins are also key players in cancer development and progression. However, structural and biochemical information on tetraspanins is decidely limited, due in no small part to the difficulties associated with expressing eukaryotic membrane proteins. In this study, we have used GFP fusions of a library of human tetraspanin proteins to identify growth conditions for expression in Escherichia coli. Three tetraspanin-GFP proteins could be produced at high enough levels to allow subsequent purification, paving the way for future structural and biochemical studies.