Organ-specific PTB1-associated microRNAs determine expression of pyruvate kinase isoforms

Sci Rep. 2015 Feb 27:5:8647. doi: 10.1038/srep08647.

Abstract

The Warburg effect is a well-known feature of cancer cells. However, its' functional significance hasn't been elucidated yet. Pyruvate kinase muscle (PKM), which is a rate-limiting glycolytic enzyme, has 2 isoforms, PKM1 and PKM2. It has been reported that PKM2 is a tumor-specific isoform and promotes the Warburg effect. Also, it has been thought that tumor cells switch their PKM isoform from PKM1 to PKM2 during tumor development. Here, we showed that this switching machinery was induced only in limited cases, based on PKM expression in normal tissues, and that brain-specific microRNA (miR)-124 and muscle-specific miR-133b regulated this machinery by controlling PKM expression through targeting polypyrimidine tract-binding protein 1 (PTB1), which is a splicer of the PKM gene. Also, we confirmed that the PKM2/PKM1 ratio was further elevated in other PKM2-dominant organs such as colon through the down-regulation of these PTB1-associated microRNAs during tumor development.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Animals
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism
  • Cell Line
  • Cell Transformation, Neoplastic / genetics
  • Cell Transformation, Neoplastic / metabolism
  • Colorectal Neoplasms / genetics
  • Colorectal Neoplasms / metabolism
  • Colorectal Neoplasms / pathology
  • Down-Regulation
  • Female
  • Gene Expression Regulation*
  • Heterogeneous-Nuclear Ribonucleoproteins / metabolism*
  • Humans
  • Isoenzymes
  • Male
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Mice
  • MicroRNAs / genetics*
  • Middle Aged
  • Models, Biological
  • Neoplasm Grading
  • Neoplasm Staging
  • Organ Specificity
  • Polypyrimidine Tract-Binding Protein / metabolism*
  • Pyruvate Kinase / genetics*
  • Pyruvate Kinase / metabolism
  • Thyroid Hormone-Binding Proteins
  • Thyroid Hormones / genetics
  • Thyroid Hormones / metabolism

Substances

  • Carrier Proteins
  • Heterogeneous-Nuclear Ribonucleoproteins
  • Isoenzymes
  • MIRN124 microRNA, human
  • MIRN133 microRNA, human
  • Membrane Proteins
  • MicroRNAs
  • PTBP1 protein, human
  • Thyroid Hormones
  • Polypyrimidine Tract-Binding Protein
  • Pyruvate Kinase