Minocycline inhibits the growth of glioma by inducing autophagy

Autophagy. 2011 Feb;7(2):166-75. doi: 10.4161/auto.7.2.14043. Epub 2011 Feb 1.

Abstract

Minocycline has been shown to alleviate several neurological disorders. Unexpectedly, we found that minocycline had opposite effects on glioma cells: minocycline induced nonapoptotic cell death in glioma cells. The glioma cell death was associated with the presence of autophagic vacuoles in the cytoplasm. Minocycline induced autophagy was confirmed by acridine orange, monodansylcadaverine (MDC) stainings of vesicle formation and the conversion of microtubule-associated proteins light chain 3 (LC3-I) to LC3-II. Pretreatment with autophagy inhibitor 3-methyladenine (3-MA) suppressed the induction of acidic vesicular organelles and the accumulation of LC3-II to the autophagosome membrane in glioma cells treated with minocycline. Despite the pretreatment of 3-MA, minocycline induced cell death which could result from the activation of caspase-3. Minocycline effectively inhibited tumor growth and induced autophagy in the xenograft tumor model of C6 glioma cells. These results suggest that minocycline may kill glioma cells by inducing autophagic cell death. When autophagy was inhibited, minocycline still induced cell death through the activation of caspase-3. Thus, minocycline is a promising agent in the treatment of malignant gliomas.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenine / analogs & derivatives
  • Adenine / pharmacology
  • Animals
  • Astrocytes / drug effects
  • Astrocytes / pathology
  • Autophagy / drug effects*
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Gene Knockdown Techniques
  • Glioma / enzymology
  • Glioma / pathology*
  • Glioma / ultrastructure
  • Mice
  • Mice, Nude
  • Minocycline / pharmacology*
  • Organelles / drug effects
  • Proto-Oncogene Proteins c-akt / metabolism
  • RNA, Small Interfering / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Ribosomal Protein S6 Kinases, 70-kDa / metabolism
  • TOR Serine-Threonine Kinases / metabolism
  • Xenograft Model Antitumor Assays

Substances

  • RNA, Small Interfering
  • 3-methyladenine
  • TOR Serine-Threonine Kinases
  • Proto-Oncogene Proteins c-akt
  • Ribosomal Protein S6 Kinases, 70-kDa
  • Minocycline
  • Adenine