RESUMEN
ABSTRACT Objective: circCPA4 has been defined to be an oncogenic gene. This study examined whether circCPA4 regulates Prostate Cancer (PC) development and revealed its molecular mechanism. Methods: PC tissues and PC cell lines were collected, in which circCPA4/miR-491-5p/SHOC2 levels were evaluated by RT-qPCR and immunoblot. Colony formation assay and EdU assay assessed cell proliferation, flow cytometry measured apoptosis, and Transwell assessed invasion and migration. Ki-67, cleaved caspase-3, E-cadherin, and N-cadherin were evaluated by immunoblot. Based on the luciferase reporter assay and RIP assay the authors investigated the targeting relationship between circCPA4/miR-491-5p/SHOC2. The effect of circCPA4 on tumor growth was evaluated by xenotransplantation in nude mice. Results: circCPA4 and SHOC2 levels were abundant while miR-491-5p expression was low in PC. Loss of circCPA4 decreased the proliferation and EdU-positive rate of PC cells, enhanced apoptosis, and inhibited invasion, migration, and EMT. Upregulation of circCPA4 forced the malignant behaviors of PC cells, and this promotion could be abolished when miR-491-5p was overexpressed or SHOC2 was silenced. CircCAP4 competitively decoyed miR-491-5p mediating SHOC2 expression. circCAP4 suppression inhibited PC tumor growth. Conclusion: circCAP4 acts as a novel oncogenic factor in PC, accelerating the malignant behavior of PC cells via miR-491-5p/SHOC2 interaction. This novel ceRNA axis may be a potential target for PC drug development and targeted therapy in the future.
RESUMEN
The canonical Wnt/β-catenin signaling pathway plays critical roles in both embryonic development and tumorigenesis. Central to the pathway is the turnover of β-catenin, a protein that functions in both cell adhesion and transcription. In the absence of a Wnt signal, free cytosolic β-catenin is phosphorylated by a large protein complex called the "β-catenin destruction complex" that targets β-catenin for degradation by an ubiquitin ligase/proteasome system. In the presence of a Wnt signal, the binding of Wnt to its receptor Frizzled and co-receptor LRP leads to the inhibition of β-catenin phosphorylation in the β-catenin destruction complex through an unknown mechanism. Inhibition of the β-catenin destruction complex leads to the accumulation of nuclear β-catenin, which in turn forms a complex with Tcf and BCL9. Recent studies have provided important clues regarding the molecular mechanism of the β-catenin destruction complex as well as an explanation for how β-catenin switches between its roles in cell adhesion and transcription.