10253

SPRY2

Sprouty (SPRY) appears to act as a tumor suppressor in cancer, whereas we demonstrated that SPRY2 functions as a putative oncogene in colorectal cancer (CRC) (Oncogene, 2010, 29: 5241-5253). We investigated the mechanisms by which SPRY regulates epithelial-mesenchymal transition (EMT) in CRC. SPRY1 and SPRY2 mRNA transcripts were significantly upregulated in human CRC. Suppression of SPRY2 repressed AKT2 and EMT-inducing transcription factors and significantly increased E-cadherin expression. Concurrent downregulation of SPRY1 and SPRY2 also increased E-cadherin and suppressed mesenchymal markers in colon cancer cells. An inverse expression pattern between AKT2 and E-cadherin was established in a human CRC tissue microarray. SPRY2 negatively regulated miR-194-5p that interacts with AKT2 3' untranslated region. Mir-194 mimics increased E-cadherin expression and suppressed cancer cell migration and invasion. By confocal microscopy, we demonstrated redistribution of E-cadherin to plasma membrane in colon cancer cells transfected with miR-194. Spry1(-/-) and Spry2(-/-) double mutant mouse embryonic fibroblasts exhibited decreased cell migration while acquiring several epithelial markers. In CRC, SPRY drive EMT and may serve as a biomarker of poor prognosis.

BACKGROUND/AIMS: Gastric cancer (GC) is one of the most prevalent digestive malignancies. MicroRNAs (miRNAs) are involved in multiple cellular processes, including oncogenesis, and miR-592 itself participates in many malignancies; however, its role in GC remains unknown. In this study, we investigated the expression and molecular mechanisms of miR-592 in GC. METHODS: Quantitative real-time PCR and immunohistochemistry were performed to determine the expression of miR-592 and its putative targets in human tissues and cell lines. Proliferation, migration, and invasion were evaluated by Cell Counting Kit-8, population doubling time, colony formation, Transwell, and wound-healing assays in transfected GC cells in vitro. A dual-luciferase reporter assay was used to determine whether miR-592 could directly bind its target. A tumorigenesis assay was used to study whether miR-592 affected GC growth in vivo. Proteins involved in signaling pathways and the epithelial-mesenchymal transition (EMT) were detected with western blot. RESULTS: The ectopic expression of miR-592 promoted GC proliferation, migration, and invasion in vitro and facilitated tumorigenesis in vivo. Spry2 was a direct target of miR-592 and Spry2 overexpression partially counteracted the effects of miR-592. miR-592 induced the EMT and promoted its progression in GC via the PI3K/AKT and MAPK/ERK signaling pathways by inhibiting Spry2. CONCLUSIONS: Overexpression of miR-592 promotes GC proliferation, migration, and invasion and induces the EMT via the PI3K/AKT and MAPK/ERK signaling pathways by inhibiting Spry2, suggesting a potential therapeutic target for GC.CI - (c) 2018 The Author(s). Published by S. Karger AG, Basel.

BACKGROUND: Early invasion and metastasis are responsible for the dismal prognosis of pancreatic ductal adenocarcinoma (PDAC), and epithelial-to-mesenchymal transition (EMT) is recognized as a crucial biological progress in driving tumor invasion and metastasis. The transcription factor FOXO3a is inactivated in various types of solid cancers and the loss of FOXO3a is associated with EMT and tumor metastasis. In this study, we sought to explore whether SPRY2, a regulator of receptor tyrosine kinase (RTK) signaling, is involved in FOXO3a-mediated EMT and metastasis in PDAC. METHODS: Immunohistochemistry was performed in 130 paired PDAC tissues and paracarcinomatous pancreatic tissues. Cell proliferation and apoptosis were assessed by cell counting kit and flow cytometry, while cell migration and invasion were evaluated with wound healing and transwell assays. The changes in mRNA and protein levels were estimated by qRT-PCR and western blot. BALB/c nude mice xenograft model was established to evaluate tumorigenesis and metastasis in vivo. RESULTS: FOXO3a expression was remarkably reduced in PDAC tissues, and correlated with metastasis-associated clinicopathologic characteristics and poor prognosis in patients with PDAC. In addition to the promotion of proliferation and suppression of apoptosis, knockdown of FOXO3a or SPRY2 induced EMT and promoted the migration and invasion of PDAC cells via activation of the beta-catenin/TCF4 pathway. Moreover, silencing of SPRY2 reversed the suppressor effects induced by FOXO3a overexpression on EMT-associated migration and invasion of PDAC cells, while blockade of beta-catenin reversed the effects of SPRY2 loss. FOXO3a knockdown decreased SPRY2 protein stability, whereas SPRY2 knockdown enhanced beta-catenin protein stability. In vivo, FOXO3a knockdown promoted the tumorigenic ability and metastasis of PDAC cells. CONCLUSIONS: Our study suggests that knockdown of FOXO3a induces EMT and promotes metastasis of PDAC by activation of the beta-catenin/TCF4 pathway through SPRY2. Thus, FOXO3a may represent a candidate therapeutic target in PDAC.