microRNA-200c-3p suppresses proliferation and invasion of nephroblastoma cells by targeting EP300 and inactivating the AKT/FOXO1/p27 pathway.

miR-200c-3p is aberrantly expressed in numerous cancers, but its underlying mechanisms in nephroblastoma are unknown. In our study, the differentially regulated miRNAs between the nephroblastoma tissues and adjacent non-neoplastic renal tissues were screened based on microarray analysis. The miR-200c-3p expression in nephroblastoma tissues and cells was detected by qRT-PCR. Then, the effects of miR-200c-3p mimic or inhibitor on cell proliferation, invasion, and migration were evaluated by CCK-8 assay, plate colony formation assay, soft agar assay, Transwell, and wound-healing assay in SK-NEP-1 and G401 cells. Afterward, the target gene of miR-200c-3p was predicted by TarBase, miRTarBase, miRDB softwares, and then verified by dual-luciferase reporter gene assay. The in vivo effects of miR-200c-3p on pathological changes and tumor volume were investigated in tumor xenograft mice by H&E staining and in vivo fluorescence imaging. ChIP assay was used to evaluate the relationship between histone acetyltransferase E1A-binding protein p300 (EP300) and P27, and the relationship of the role of miR-200c-3p in nephroblastoma and the AKT/FOXO1/p27 signaling pathways was evaluated by western blotting. Our study shows that miR-200c-3p was downregulated in nephroblastoma tissues and cells, and EP300 was a target gene of miR-200c-3p. Furthermore, miR-200c-3p mimic decreased cell proliferation and inhibited cell migration and invasion in nephroblastoma. Mechanistically, miR-200c-3p could inhibit p-AKT activity and enhance p-FOXO1 and p27 expression. Notably, the transcription factor P27 could bind to the EP300 promoter. This study demonstrates a new approach to treat nephroblastoma.

CCAT1 promotes triple-negative breast cancer progression by suppressing miR-218/ZFX signaling.

Long non-coding RNAs (lncRNAs) regulate cancer development and progression. Here, we investigated the role of the lncRNA CCAT1 in triple-negative breast cancer (TNBC). CCAT1 expression was higher in TNBC cells than normal breast epithelial cells. Additionally, CCAT1 expression was higher in TNBC patient tumor tissue than adjacent normal breast tissue. Silencing CCAT1 inhibited TNBC cell proliferation, migration, and invasion in vitro, and tumor growth and progression in vivo. Bioinformatics analysis revealed that microRNA-218 (miR-218) is a potential target of CCAT1. Silencing CCAT1 resulted in an increase in miR-218 expression and inhibited TNBC cell proliferation, migration, and invasion. Silencing miR-218 reversed the effects of CCAT1 knockdown on cell proliferation, migration, and invasion, suggesting that CCAT1 promotes TNBC progression by downregulating miR-218 expression. We identified the zinc finger protein ZFX as a putative downstream target of miR-218 through bioinformatics analysis. ZFX expression was higher in TNBC than normal breast cell lines and higher in TNBC tumor tissue than adjacent normal breast tissue. Overexpression of ZFX reversed the tumor-suppressive effects of miR-218 on TNBC cell proliferation, migration, and invasion. Our data indicate that CCAT1 promotes TNBC progression by targeting the miR-218/ZFX axis.