Recepteur d'Origine Nantais (RON) is a distinct receptor tyrosine kinase in the c-met proto-oncogene family. We examined the mutational and expression patterns of RON in eight human uroepithelial cell lines. Biological effects of RON overexpression on cancer cells were investigated in vitro, and the prognostic significance of RON and/or c-met protein (MET) expression was analysed in a bladder cancer cohort (n=183). There was no evidence of mutation in the kinase domain of RON. Overexpression of RON using an inducible Tet-off system induced increased cell proliferation, motility, and antiapoptosis. Immunohistochemical analysis showed that RON was overexpressed in 60 cases (32.8%) of primary tumours, with 14 (23.3%) showing a high level of expression. Recepteur d'Origine Nantais expression was positively associated with histological grading, larger size, nonpapillary contour, and tumour stage (all P<0.01). In addition, MET was overexpressed in 82 cases (44.8%). Co-expressed RON and MET was significantly associated with decreased overall survival (P=0.005) or metastasis-free survival (P=0.01) in 35 cases (19.1%). Recepteur d'Origine Nantais-associated signalling may play an important role in the progression of human bladder cancer. Evaluation of RON and MET expression status may identify a subset of bladder-cancer patients who require more intensive treatment.

Background: A cross-talk between different receptor tyrosine kinases (RTKs) plays an important role in the pathogenesis of human cancers.Methods: Both NIH-Met5 and T24-Met3 cell lines harboring an inducible human c-Met gene were established. C-Met-related RTKs were screened by RTK microarray analysis. The cross-talk of RTKs was demonstrated by Western blotting and confirmed by small interfering RNA (siRNA) silencing, followed by elucidation of the underlying mechanism. The impact of this cross-talk on biological function was demonstrated by Trans-well migration assay. Finally, the potential clinical importance was examined in a cohort of 65 cases of locally advanced and metastatic bladder cancer patients.Results: A positive association of Axl or platelet-derived growth factor receptor-alpha (PDGFR-α) with c-Met expression was demonstrated at translational level, and confirmed by specific siRNA knock-down. The transactivation of c-Met on Axl or PDGFR-αin vitrowas through aras- and Src-independent activation of mitogen-activated protein kinase/extracellular signal-regulated kinase (MEK/ERK) pathway. In human bladder cancer, co-expression of these RTKs was associated with poor patient survival (p< 0.05), and overexpression of c-Met/Axl/PDGFR-α or c-Met alone showed the most significant correlation with poor survival (p< 0.01).Conclusions: In addition to c-Met, the cross-talk with Axl and/or PDGFR-α also contributes to the progression of human bladder cancer. Evaluation of Axl and PDGFR-α expression status may identify a subset of c-Met-positive bladder cancer patients who may require co-targeting therapy.

In our preliminary screening, expression of miR-338-5p was found to be higher in primary colorectal cancer (CRC) with metastasis. The autophagy related gene- phosphatidylinositol 3-kinase, catalytic subunit type 3 (PIK3C3) appeared to be targeted by miR-338-5p. Here, we provide solid evidence in support of PIK3C3 involved in miR-338-5p related metastasis of CRC in vitro and in vivo. The potential clinical relevance of miR-338-5p and its target gene was analysed on benign colorectal polyps and primary CRCs by QPCR. Mouse spleen xenograft experiment was performed to examine the importance of miR-338-5p for metastasis. PIK3C3 was one of target genes of miR-338-5p. In primary CRCs, expression of miR-338-5p is positively related to tumour staging, distant metastasis and poor patient survival. Patients with higher ratios of miR-338-5p/PIK3C3 also had significantly poor overall survival, supporting their significance in the progression of CRC. Over-expression of miR-338-5p promotes CRC metastasis to the liver and lung in vivo, in which PIK3C3 was down-regulated in the metastatic tumours. In contrast, overexpression of PIK3C3 in miR-338-5p stable cells inhibited the growth of metastatic tumours. Both migration and invasion of CRC in vitro induced by miR-338-5p are mediated by suppression of PIK3C3. Using forward and reverse approaches, autophagy was proved to involve in CRC migration and invasion induced by miR-338-5p. MiR-338-5p induces migration, invasion and metastasis of CRC in part through PIK3C3-related autophagy pathway. The miR-338-5p/PIK3C3 ratio may become a prognostic biomarker for CRC patients. FUND: NCKU Hospital, Taiwan, Ministry of Science and Technology, Taiwan.

Purpose: Mass spectrometry–based biomarker discovery has clinical benefit. To identify novel biomarkers for urothelial carcinoma, we performed quantitative proteomics on pooled urine pairs from patients with and without urothelial carcinoma. Experimental Design: Shot-gun proteomics using liquid chromatography-tandem mass spectrometry and stable isotope dimethyl labeling identified 219 candidate proteins. The potential implication of SH3 domain binding glutamic acid-rich protein like 3 (SH3BGRL3) was examined by immunoblotting of the urine (n = 13) and urothelial tumors (n = 32). Additional immunohistochemistry was performed on bladder cancer array (n = 1145) and correlated with tumor aggressiveness. Then, biologic functions and signaling pathways of SH3BGRL3 were explored using stable cell lines. Results: The detectable urine SH3BGRL3 in patients with urothelial carcinoma was positively associated with higher histologic grading and muscle invasiveness of urothelial carcinoma. SH3BGRL3 is expressed in 13.9% (159/1145) of bladder cancer cohort and is positively associated with muscle invasion (P = 0.0028). SH3BGRL3 expression is associated with increased risk of progression in patients with nonmuscle-invasive bladder cancer (P = 0.032). SH3BGRL3 expression is significantly associated with a high level of epidermal growth factor receptor (EGFR) in bladder cancer (P < 0.0001). SH3BGRL3 promotes the epithelial–mesenchymal transition, cell migration, and proliferation of urothelial carcinoma in vitro. SH3BGRL3 interacts with phosphor-EGFR at Y1068, Y1086, and Y1173 through Grb2 by its proline-rich motif, and activates the Akt-associated signaling pathway. Conclusions: Evaluation of SH3BGRL3 expression status or urine content may identify a subset of patients with bladder cancer who may require more intensive treatment. SH3BGRL3 deserves further investigation as a cotargeting candidate for designing EGFR-based cancer therapies. Clin Cancer Res; 21(24); 5601–11. ©2015 AACR.