Advertisement
Advanced searchCitation search
Skip main navigation
You are prohibited from using or uploading content you accessed through this website into external applications, bots, software, or websites, including those using artificial intelligence technologies and infrastructure, including deep learning, machine learning and large language models and generative AI.
Advertisement
You have accessJournal of UrologyKidney Cancer: Basic Research I1 Apr 2014

MP23-06 MICRORNAS AND WARBURG EFFECT: NEW BIOLOGICAL PATHWAYS IN RENAL CELL CARCINOMA

    View All Author Information
    https://doi.org/10.1016/j.juro.2014.02.874

    INTRODUCTION AND OBJECTIVES

    Unlike normal differentiated cells, tumor cells metabolize glucose via glycolysis under aerobic conditions, a hallmark of cancer known as the Warburg effect. Renal cell carcinoma (RCC) often has a mutation of VHL and HIF-1 gene is constitutively activated mediating the Warburg effect. Our recent microRNA (miRNA) expression signature of RCC revealed that tumor suppressive miR-1291 targets glucose transporter 1 and miR-143/145 cluster target hexokinase 2. Pyruvate dehydrogenase kinase 1 (PDK1) is an important regulator of pyruvate dehydrogenase and is regulated by HIF-1 in cancer. The aim of this study is to investigate miRNAs regulating PDK1 gene in RCC.

    METHODS

    We searched miRNAs targeting PDK1 gene through TargetScan database. A luciferase reporter assay was carried out to determine whether 3′UTR of PDK1 has an actual biding site for candidate miRNAs. We investigated whether PDK1 was regulated by miR-24 by real-time PCR and western blotting. The expression level of miR-24 and PDK1 in clinical RCCs (n=29) and normal kidney specimens (n=27) were evaluated by real-time PCR. Overall survival (OS) of RCC patients was evaluated using the Kaplan-Meier method. To investigate the functional role of miR-24, we performed gain-of-function studies (cell proliferation, apoptosis and cell cycle assay) by using miR-24 transfectants (786-O and A498 cancer cell lines).

    RESULTS

    In clinical specimens, expression levels of PDK1 were significantly up-regulated in RCC specimens compared with the normal specimens (P<0.0001). Western blot and luciferase reporter analysis showed that miR-24 directly targets PDK1. MiR-24 expression level was significantly lower in high grade group compared to low grade group (P=0.0286). MiR-24 expression level was significantly lower in recurrence group of patients compared to no-recurrence group (P=0.0498). Kaplan-Meier analysis showed that the low miR-24 group had significantly lower OS probability compared to the high miR-24 group (P=0.0438). XTT assay demonstrated that cell viability was significantly inhibited in the miR-24 transfectants compared with the control. Flow cytometry analysis showed that cell cycle arrest and apoptosis were induced in the miR-24 transfectants.

    CONCLUSIONS: miR-24 functions as a tumor suppressor in RCC through inhibition of PDK1 suggesting that miR-24 might be a potential biomarker for prognosis prediction in the treatment of RCC.

    © 2014