RESUMO
Hepatocellular carcinoma (HCC) poses a significant threat due to its highly aggressive and high recurrence characteristics, necessitating urgent advances in diagnostic and therapeutic approaches. Long non-coding RNAs exert vital roles in HCC tumorigenesis, however the mechanisms of their expression regulation and functions are not fully elucidated yet. Herein, we identify that a novel tumor suppressor 'lnc-PIK3R1' was significantly downregulated in HCC tissues, which was correlated with poor prognosis. Functionally, lnc-PIK3R1 played tumor suppressor roles to inhibit the proliferation and mobility of HCC cells, and to impede the distant implantation of xenograft in mice. Mechanistic studies revealed that lnc-PIK3R1 interacted with miR-1286 and alleviated the repression on GSK3B by miR-1286. Notably, pharmacological inhibition of GSK3ß compromised the tumor suppression effect by lnc-PIK3R1, confirming their functional relevance. Moreover, we identified that oncogenic YY1 acts as a specific transcriptional repressor to downregulate the expression of lnc-PIK3R1 in HCC. In summary, this study highlights the tumor-suppressive effect of lnc-PIK3R1, and provides new insights into the regulation of GSK3ß expression in HCC, which would benefit the development of innovative intervention strategies for HCC.
Assuntos
Carcinoma Hepatocelular , Classe Ia de Fosfatidilinositol 3-Quinase , Regulação Neoplásica da Expressão Gênica , Glicogênio Sintase Quinase 3 beta , Neoplasias Hepáticas , MicroRNAs , RNA Longo não Codificante , Fator de Transcrição YY1 , Humanos , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Carcinoma Hepatocelular/metabolismo , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Glicogênio Sintase Quinase 3 beta/metabolismo , Glicogênio Sintase Quinase 3 beta/genética , MicroRNAs/genética , MicroRNAs/metabolismo , Animais , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , Fator de Transcrição YY1/metabolismo , Fator de Transcrição YY1/genética , Camundongos , Classe Ia de Fosfatidilinositol 3-Quinase/metabolismo , Classe Ia de Fosfatidilinositol 3-Quinase/genética , Progressão da Doença , Proliferação de Células/genética , Linhagem Celular Tumoral , Masculino , Camundongos Nus , FemininoRESUMO
Soft-tissue sarcomas (STS) emerges as formidable challenges in clinics due to the complex genetic heterogeneity, high rates of local recurrence and metastasis. Exploring specific targets and biomarkers would benefit the prognosis and treatment of STS. Here, we identified RCC1, a guanine-nucleotide exchange factor for Ran, as an oncogene and a potential intervention target in STS. Bioinformatics analysis indicated that RCC1 is highly expressed and correlated with poor prognosis in STS. Functional studies showed that RCC1 knockdown significantly inhibited the cell cycle transition, proliferation and migration of STS cells in vitro, and the growth of STS xenografts in mice. Mechanistically, we identified Skp2 as a downstream target of RCC1 in STS. Loss of RCC1 substantially diminished Skp2 abundance by compromising its protein stability, resulting in the upregulation of p27Kip1 and G1/S transition arrest. Specifically, RCC1 might facilitate the nucleo-cytoplasmic trafficking of Skp2 via direct interaction. As a result, the cytoplasmic retention of Skp2 would further protect it from ubiquitination and degradation. Notably, recovery of Skp2 expression largely reversed the phenotypes induced by RCC1 knockdown in STS cells. Collectively, this study unveils a novel RCC1-Skp2-p27Kip1 axis in STS oncogenesis, which holds promise for improving prognosis and treatment of this formidable malignancy.
