title: A lentiviral sponge for miRNA-21 diminishes aerobic glycolysis in bladder cancer T24 cells via the PTEN/PI3K/AKT/mTOR axis.
abstract: Cancer cells exhibit the ability to metabolise glucose to lactate even under aerobic conditions for energy. This phenomenon is known as the Warburg effect and can be a potential target to kill cancer cells. Several studies have shown evidence for interplay between microRNAs and key metabolic enzyme effecters, which can facilitate the Warburg effect in cancer cells. In the present study, a microRNA sponge forcibly expressed using a lentiviral vector was utilised to knock down miR-21 expression in vitro. qPCR and Western blot assays were performed to evaluate the expression of a regulatory factor related to aerobic glycolysis and the signalling pathway it regulates. In bladder cancer specimens, expression levels of glycolysis-related genes [glucose transporter (GLUT)1, GLUT3, lactic dehydrogenase (LDH)A, LDHB, hexokinase (HK)1, HK2, pyruvate kinase type M (PKM) and hypoxia-inducible factor 1-alpha (HIF-1α)] were higher in tumour tissues than in adjacent tissues, suggesting the role of glycolysis in bladder cancer. miR-21 inhibition in bladder cancer cell lines resulted in reduction in tumour aerobic glycolysis. Decrease in glucose uptake and lactate production was observed upon expression of the miR-21 sponge, which promoted phosphatase and tensin homologue (PTEN) expression, decreased phosphorylated AKT and deactivated mTOR. Furthermore, messenger RNA (mRNA) and protein expression levels of glycolysis-related genes were also lower in miR-21 sponge cells compared to miR-21 control cells. Our findings suggest that miR-21 acts as a molecular switch to regulate aerobic glycolysis in bladder cancer cells via the PTEN/phosphatidylinositol 3-kinase (PI3K)/AKT/mTOR pathway. Blocking miR-21 function can be an effective diagnostic and therapeutic approach either by itself or in combination with existing methods to treat bladder cancer.
authors.affiliation: Department of Urology, The First Affiliated Hospital, Nanjing Medical University, Nanjing, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Yang
authors.forename: Yidong
authors.initials: Y
authors.lastname: Cheng
authors.forename: Pengchao
authors.initials: P
authors.lastname: Li
authors.forename: Jun
authors.initials: J
authors.lastname: Tao
authors.forename: Xiaheng
authors.initials: X
authors.lastname: Deng
authors.forename: Xiaolei
authors.initials: X
authors.lastname: Zhang
authors.forename: Min
authors.initials: M
authors.lastname: Gu
authors.forename: Qiang
authors.initials: Q
authors.lastname: Lu
authors.forename: Changjun
authors.initials: C
authors.lastname: Yin
mesh_terms: D045744:Cell Line, Tumor; D015870:Gene Expression; D015972:Gene Expression Regulation, Neoplastic; D055785:Gene Knockdown Techniques; D005947:Glucose / Q000378:metabolism; D006019:Glycolysis; D006801:Humans; D016086:Lentivirus; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D051059:PTEN Phosphohydrolase / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D015398:Signal Transduction; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism; D014161:Transduction, Genetic; D001749:Urinary Bladder Neoplasms
chemical_list: D005947:Glucose; D035683:MicroRNAs; D051059:PTEN Phosphohydrolase; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D058570:TOR Serine-Threonine Kinases; C524940:MIRN21 microRNA, human; C546842:MTOR protein, human; C494929:PTEN protein, human