RESUMO
RIOK1 has recently been shown to play important roles in cancers, but its posttranslational regulation is largely unknown. Here we report that RIOK1 is methylated at K411 by SETD7 methyltransferase and that lysine-specific demethylase 1 (LSD1) reverses its methylation. The mutated RIOK1 (K411R) that cannot be methylated exhibits a longer half-life than does the methylated RIOK1. FBXO6 specifically interacts with K411-methylated RIOK1 through its FBA domain to induce RIOK1 ubiquitination. Casein kinase 2 (CK2) phosphorylates RIOK1 at T410, which stabilizes RIOK1 by antagonizing K411 methylation and impeding the recruitment of FBXO6 to RIOK1. Functional experiments demonstrate the RIOK1 methylation reduces the tumor growth and metastasis in mice model. Importantly, the protein levels of CK2 and LSD1 show an inverse correlation with FBXO6 and SETD7 expression in human colorectal cancer tissues. Together, this study highlights the importance of a RIOK1 methylation-phosphorylation switch in determining colorectal and gastric cancer development.
Assuntos
Antígenos de Neoplasias/metabolismo , Neoplasias Colorretais/patologia , Processamento de Proteína Pós-Traducional , Neoplasias Gástricas/patologia , Animais , Caseína Quinase II/metabolismo , Linhagem Celular Tumoral , Modelos Animais de Doenças , Histona Desmetilases/metabolismo , Histona-Lisina N-Metiltransferase/metabolismo , Humanos , Metilação , Camundongos , Fosforilação , Ligação Proteica , Proteínas Serina-Treonina Quinases , Proteínas Ligases SKP Culina F-Box/metabolismo , UbiquitinaçãoRESUMO
Altered expression of microRNA-590-5p (miR-590-5p) is involved in tumorigenesis, however, its role in colorectal cancer (CRC) remains to be determined. In this study, we focused on examining the effects of different expression levels of miR-590-5p in cancer cells and normal cells. Results showed that there are lower expression levels of miR-590-5p in human CRC cells and tissues than in normal control cells and tissues. Similarly, in our xenograft mouse model, knockdown of miR-590-5p promoted the progression of CRC. However, an overexpression of miR-590-5p in the mice inhibited angiogenesis, tumor growth, and lung metastasis. Nuclear factor 90 (NF90), a positive regulator of vascular endothelial growth factor (VEGF) mRNA stability and protein synthesis, was shown to be a direct target of miR-590-5p. The overexpression of NF90 restored VEGFA expression and rescued the loss of tumor angiogenesis caused by miR-590-5p. Conversely, the NF90-shRNA attenuated the increased tumor progression caused by the miR-590-5p inhibitor. Clinically, the levels of miR-590-5p were inversely correlated with those of NF90 and VEGFA in CRC tissues. Furthermore, knockdown of NF90 lead to a reduction of pri-miR-590 and an increase of mature miR-590-5p, suggesting a negative feedback loop between miR-590-5p and NF90. Collectively, these data establish miR-590-5p as an anti-onco-miR that inhibits CRC angiogenesis and metastasis through a new mechanism involving NF90/VEGFA signaling axis, highlighting the potential of miR-590-5p as a target for human CRC therapy.
Assuntos
Neoplasias Colorretais/irrigação sanguínea , Neoplasias Colorretais/genética , MicroRNAs/metabolismo , Neovascularização Patológica/genética , Proteínas do Fator Nuclear 90/genética , Transdução de Sinais , Fator A de Crescimento do Endotélio Vascular/genética , Animais , Carcinogênese/genética , Carcinogênese/patologia , Linhagem Celular Tumoral , Galinhas , Neoplasias Colorretais/patologia , Regulação para Baixo/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Técnicas de Silenciamento de Genes , Células HEK293 , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Masculino , Camundongos SCID , MicroRNAs/genética , Pessoa de Meia-Idade , Metástase Neoplásica , Neovascularização Patológica/patologia , Proteínas do Fator Nuclear 90/metabolismo , Análise de Sobrevida , Fator A de Crescimento do Endotélio Vascular/metabolismoRESUMO
MicroRNAs (miRs) function as key regulators of gene expression and their deregulation is associated with the carcinogenesis of various cancers. In the present study, we investigated the biological role and mechanism of miR-361-5p in colorectal carcinoma (CRC) and gastric cancer (GC). We showed that microRNA-361-5p (miR-361-5p) was down-regulated in CRC and GC in comparison to the controls. Meanwhile, the expression levels of miR-361-5p negatively correlated with lung metastasis and prognosis in clinical CRC patients. Overexpression of miR-361-5p markedly suppressed proliferation, migration and invasion of cancer cells. Additionally, this phenotype could be partially rescued by the ectopic expression of staphylococcal nuclease domain containing-1 (SND1). SND1 was identified as a target of miR-361-5p using bioinformatics analysis and in vitro luciferase reporter assays. In turn, SND1 bound to pre-miR-361-5p and suppressed the expression of miR-361-5p, thus exerting a feedback loop. Most interestingly, in vivo studies showed that restoration of miR-361-5p significantly inhibited tumor growth and especially the lung metastasis in nude mice. Therefore, it could be concluded that miR-361-5p functions as a tumor-suppressive miRNA through directly binding to SND1, highlighting its potential as a novel agent for the treatment of patients with CRC and GC.