circTADA2A inhibited SLC38A1 expression and suppresses melanoma progression through the prevention of CNBP trans-activation

Abstract

Background CircTADA2A has been demonstrated to play critical roles in the occurrence and development of human cancer. However, the expression pattern and biological mechanisms of circTADA2A in melanoma remains largely unknown. Methods CircTADA2A were detected by quantitative real-time RT-PCR (qRT-PCR) and validated by Sanger sequencing. Function of circTADA2A and its protein partner in melanoma cells was investigated using RNA interference and overexpression assays. Interaction of circTADA2A, CCHC-type zinc finger nucleic acid binding protein (CNBP) and solute carrier family 38 member 1 (SLC38A1) was confirmed by RNA immunoprecipitation, RNA pull-down, and dual-luciferase reporter assay. The expression of genes and proteins were detected by qRT-PCR and western blot assays. Results Data from the investigation showed that a novel circRNA (circTADA2A, hsa_circ_0043278) was markedly downregulated in melanoma cells. Functionally, circTADA2A repressed cell proliferation, migration, invasion in melanoma cells. Mechanistically, circTADA2A interacted with CNBP, acting to suppress the binding of CNBP to the SLC38A1 promoter and subsequently restrained SLC38A1 transcription, which resulting in repression of melanoma progression. Conclusions CircTADA2A suppresses melanoma progression by regulating CNBP/SLC38A1 axis, indicating a potential therapeutic target in melanoma.