ADP‐ribosylation factor 6 (ARF6) is a well‐studied protein that is involved in multiple biological functions including cell migration and invasion. The mechanism by which ARF6 regulates the migration and invasion of upper tract urothelial carcinoma (UTUC) is still unknown. MiR‐145‐5p is a tumor suppressor microRNA, which is downregulated in several cancer types. We aimed to elucidate the molecular mechanism underlying the regulation of ARF6 by miR‐145‐5p in UTUC. ARF6 expression was observed to be higher in UTUC tissues than paired adjacent normal tissues. A reverse correlation between ARF6 and miR‐145‐5p was found in UTUC tissues. MiR‐145‐5p inhibited ARF6 expression by directly targeting its 3′‐UTR. The functional studies indicated that ARF6 expression reversed the miR‐145‐5p‐reduced tumor cell migration and invasion. Notably, miR‐145‐5p reduced MMP2, N‐cadherin, FAK and MMP7, and elevated E‐cadherin protein levels in vitro; however, the above effects were reversed by ARF6. Further, the expression of epithelial‐to‐mesenchymal transition (EMT) markers and cell invasion was suppressed by knocking down MMP7 in UTUC cells. These findings suggest that miR‐145‐5p may suppress UTUC cell motility and invasion by targeting ARF6/MMP7 through EMT.

Background: Hypoxia has been shown to facilitate tumor progression. Hypoxia-regulated microRNA-210 (miR-210) may play an important role in carcinogenesis and tumor progression. In this study, we evaluated the clinical significance of miR-210 expression in upper tract urothelial carcinoma (UTUC).

Background. Colony-stimulating factor-1 (CSF-1) is a homodimeric glycoprotein. The main role of CSF-1 is as a hematopoietic growth factor that modulates proliferation, differentiation, and survival of macrophages. Moreover, CSF-1 has also been reported to be aberrantly expressed in several human cancers. However, the precise role of CSF-1 in upper tract urothelial carcinomas (UTUC) has not been studied. In this research, we examined the clinical significance of CSF-1 expression in UTUC. Materials and Methods. One hundred twelve cancer tissue samples of UTUC from patients were included in this study, and the other cohort of 35 UTUC were paired cancer-adjacent normal samples. CSF-1 expression was evaluated by immunohistochemistry, and the association of CSF-1 expression with different clinicopathological variables was analyzed. Results. CSF-1 expression was higher in UTUC than in the normal urothelium (P=0.005). The CSF-1 expression was primarily localized in the nucleus and was significantly correlated with tumor size (P=0.04) and patients who had a high stage (P<0.001), distant metastasis (P=0.006), recurrence (P=0.003), and cancer death (P=0.005). High CSF-1 expression was correlated with poor disease-free survival (P=0.008) and cancer-specific survival (P=0.001). Our results also used univariate and multivariable analyses, which found that high CSF-1 expression was an independent predictor of poor disease-free survival (hazardratio=2.56; P=0.007) and cancer-specific survival (hazardratio=5.14; P=0.022). Conclusions. Our findings indicate that the expression of CSF-1 is a potential prognostic marker for predicting patient survival and recurrence in UTUC.