GP73 promotes invasion and metastasis of bladder cancer by regulating the epithelial–mesenchymal transition through the TGF‐β1/Smad2 signalling pathway

Abstract

This study investigated the effects of Golgi membrane protein 73 (GP73) on the epithelial–mesenchymal transition (EMT) and on bladder cancer cell invasion and metastasis through the TGF‐β1/Smad2 signalling pathway. Paired bladder cancer and adjacent tissue samples (102) and normal bladder tissue samples (106) were obtained. Bladder cancer cell lines (T24, 5637, RT4, 253J and J82) were selected and assigned to blank, negative control (NC), TGF‐β, thrombospondin‐1 (TSP‐1), TGF‐β1+ TSP‐1, GP73‐siRNA‐1, GP73‐siRNA‐2, GP73‐siRNA‐1+ TSP‐1, GP73‐siRNA‐1+ pcDNA‐GP73, WT1‐siRNA and WT1‐siRNA + GP73‐siRNA‐1 groups. Expressions of GP73, TGF‐β1, Smad2, p‐Smad2, E‐cadherin and vimentin were detected using RT‐qPCR and Western blotting. Cell proliferation, migration and invasion were determined using MTT assay, scratch testing and Transwell assay, respectively. Compared with the blank and NC groups, levels of GP73, TGF‐β1, Smad2, p‐Smad2, N‐cadherin and vimentin decreased, and levels of WT1 and E‐cadherin increased in the GP73‐siRNA‐1 and GP73‐siRNA‐2 groups, while the opposite results were observed in the WT1 siRNA, TGF‐β, TSP‐1 and TGF‐β + TSP‐1 groups. Cell proliferation, migration and invasion notably decreased in the GP73‐siRNA‐1 and GP73‐siRNA‐2 groups in comparison with the blank and NC groups, while in the WT1 siRNA, TGF‐β, TSP‐1 and TGF‐β + TSP‐1 groups, cell migration, invasion and proliferation showed the reduction after the EMT. These results suggest that GP73 promotes bladder cancer invasion and metastasis by inducing the EMT through down‐regulating WT1 levels and activating the TGF‐β1/Smad2 signalling pathway.

TGF-β-induced transgelin promotes bladder cancer metastasis by regulating epithelial-mesenchymal transition and invadopodia formation

“…TGF-β signalling is undoubtedly a central player in cancer progression due to its dual functioning [42]. Not to mention, TGF-β acts as a lymph node metastatic biomarker [60] and is involved in the invasion and metastasis of BLCA [61,62]. Furthermore, TGF-β reprograms the tumour microenvironment to attenuate anti-tumour immunity in metastatic bladder cancer [63].…”

TGF-β and microRNA Interplay in Genitourinary Cancers

“…For instance, EIF5A2 stimulates TGF-β1 expression via STAT3 to induce EMT and stimulate migration and invasion [208] while cancer-associated fibroblasts (CAFs) secrete Kindlin-2, which induces EMT in a TGF-β-dependent manner [209]. The TGF-β1/SMAD2 pathway is also utilized by Golgi membrane protein 73 (GP73) to induce EMT and promote invasion and metastasis of bladder cancer [210]. TGF-β1 mediates signaling initiated by collagens.…”

Deletion of Golgi protein 73 delayed hepatocyte proliferation of mouse in the early stages of liver regeneration

“…[8][9][10][11] Concordantly, many functional studies reported that GP73 could promote proliferation and migration of tumor cells. 12,13 However, more studies from other laboratories and our own demonstrated the common presence of increased serum GP73 in patients of liver cirrhosis with different etiologies. 14,15 As mentioned above, the cell proliferation promoting role of GP73 in HCC cells has been confirmed by a number of researches.…”

“…In recent years, numerous studies have reported the significant increase of serum GP73 level in patients with hepatocellular carcinoma (HCC) and proposed it as a marker for HCC diagnosis 8–11 . Concordantly, many functional studies reported that GP73 could promote proliferation and migration of tumor cells 12,13 . However, more studies from other laboratories and our own demonstrated the common presence of increased serum GP73 in patients of liver cirrhosis with different etiologies 14,15 …”