Abstract
Glioma is the most common malignant cancer affecting the central nerve system, with dismal prognosis. Differentiation-inducing therapy is a novel strategy that has been preliminarily proved effective against malignant glioma. We have reported previously that activation of cAMP/protein kinase A (PKA) pathway is capable of inducing glioma cell differentiation, characterized by astrocyte-like shape and dramatic induction of astrocyte biomarker glial fibrillary acidic protein (GFAP). However, little progress has been made on molecular mechanisms related. Here we demonstrate that microRNA 335 (miR-335) is responsible for the glioma cell differentiation stimulated by activation of cAMP/PKA pathway. In the cAMP elevator cholera toxin-induced differentiation model of rat C6 glioma cells, miR-335 was significantly up-regulated, which was mimicked by other typical cAMP/PKA pathway activators (e.g., forskolin, dibutyryl-cAMP) and abolished by PKA-specific inhibitor (9R,10S,12S)-2,3,9,10,11,12-hexahydro-10-hydroxy-9-methyl-1-oxo-9,12-epoxy-1H-diindolo[1,2,3-fg:3′,2′,1′-kl]pyrrolo[3,4-i] [1,6]benzodiazocine-10-carboxylic acid, hexyl ester (KT5720). In an assay measuring gain and loss of miR-335 function, exogenetic miR-335 resulted in induction of GFAP, whereas miR-335 specific inhibitor antagomir-335 violently blocked cholera toxin-induced GFAP up-regulation. It is noteworthy that in human U87-MG glioma cells and human primary culture glioma cells, miR-335 also mediated cholera toxin-induced differentiation. Taken together, our findings suggest that miR-335 is potently required for differentiation of malignant glioma cells induced by cAMP/PKA pathway activation, and a single microRNA may act as an important fate determinant to control the differentiation status of malignant gliomas, which has provided a new insight into differentiation-inducing therapy against malignant gliomas.
Footnotes
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The online version of this article (available at http://molpharm.aspetjournals.org) contains supplemental material.
This work was supported by Key program, National Natural Science Foundation of China [Grant 30830111]; Guangzhou Program Project of Science Technology [Grant 2008Z1-E561]; National Key Projects of Science and Technology [Grants 2009ZX09102-013, 2009ZX09102-217]; and Guangdong Natural Science Foundation [Grant S2011040004371].
Article, publication date, and citation information can be found at http://molpharm.aspetjournals.org.
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ABBREVIATIONS:
- PKA
- protein kinase A
- GFAP
- glial fibrillary acidic protein
- miRNA
- microRNA
- DMEM
- Dulbecco's modified Eagle's medium
- FBS
- fetal bovine serum
- WHO
- World Health Organization
- dbcAMP
- dibutyryl cAMP
- KT5720
- (9R,10S,12S)-2,3,9,10,11,12-hexahydro-10-hydroxy-9-methyl-1-oxo-9,12-epoxy-1H-diindolo[1,2,3-fg:3′,2′,1′-kl]pyrrolo[3,4-i][1,6]benzodiazocine-10-carboxylic acid, hexyl ester
- qRT-PCR
- quantitative real-time polymerase chain reaction
- IL
- interleukin
- JAK
- Janus tyrosine kinase
- STAT
- signal transducer and activator of transcription
- MEST
- mesoderm-specific transcript.
- Received September 30, 2011.
- Accepted December 15, 2011.
- Copyright © 2012 The American Society for Pharmacology and Experimental Therapeutics
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