MicroRNA-345 induces apoptosis in pancreatic cancer cells through potentiation of caspase-dependent and -independent pathways

Background: Previously, miR-345 was identified as one of the most significantly downregulated microRNAs in pancreatic cancer (PC); however, its functional significance remained unexplored. Methods: miR-345 was overexpressed in PC cells by stable transfection, and its effect on growth, apoptosis and...

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Veröffentlicht in:British journal of cancer 2015-08, Vol.113 (4), p.660-668
Hauptverfasser: Srivastava, Sanjeev K, Bhardwaj, Arun, Arora, Sumit, Tyagi, Nikhil, Singh, Seema, Andrews, Joel, McClellan, Steve, Wang, Bin, Singh, Ajay P
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Sprache:eng
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Zusammenfassung:Background: Previously, miR-345 was identified as one of the most significantly downregulated microRNAs in pancreatic cancer (PC); however, its functional significance remained unexplored. Methods: miR-345 was overexpressed in PC cells by stable transfection, and its effect on growth, apoptosis and mitochondrial-membrane potential was examined by WST-1, Hoechst-33342/Annexin-V, and JC-1 staining, respectively. Gene expression was examined by quantitative reverse-transcription-PCR and/or immunoblotting, and subcellular fractions prepared and caspase-3/7 activity determined by commercially available kits. miR-345 target validation was performed by mutational analysis and luciferase-reporter assay. Results: miR-345 is significantly downregulated in PC tissues and cell lines relative to normal pancreatic cells, and its expression decreases gradually in PC progression model cell lines. Forced expression of miR-345 results in reduced growth of PC cells because of the induction of apoptosis, accompanied by a loss in mitochondrial membrane potential, cytochrome- c release, caspases-3/7 activation, and PARP-1 cleavage, as well as mitochondrial-to-nuclear translocation of apoptosis-inducing factor. These effects could be reversed by the treatment of miR-345-overexpressing PC cells with anti-miR-345 oligonucleotides. BCL2 was characterised as a novel target of miR-345 and its forced-expression abrogated the effects of miR-345 in PC cells. Conclusions: miR-345 downregulation confers apoptosis resistance to PC cells, and its restoration could be exploited for therapeutic benefit.
ISSN:0007-0920
1532-1827
DOI:10.1038/bjc.2015.252