Peptide nucleic acids targeting miR-221 modulate p27Kip1 expression in breast cancer MDA-MB-231 cells.

Abstract

The activity of a peptide nucleic acid (PNA) targeting cancer-associated microRNA-221 is described. PNAs against miR-221 were designed in order to bind very efficiently to the target RNA strand and to undergo efficient uptake in the cells. A polyarginine-PNA conjugate targeted against miR-221 (Rpep-PNA-a221) showed both very high affinity for RNA and efficient cellular uptake without the addition of transfection reagents. Unmodified PNA with the same sequence displayed RNA binding, but cellular uptake was very poor. Consistently, only Rpep-PNA-a221 strongly inhibited miR-221. Targeting miR-221 by PNA resulted in i) lowering of the hybridization levels of miR-221 measured by RT-qPCR, ii) upregulation of p27Kip1 gene expression, measured by RT-qPCR and western blot analysis. The major conclusion of this study is that efficient delivery of anti‑miR PNA through a suitable peptide carrier (Rpep‑PNA-a221) leads to inhibition of miR-221 activity, altering the expression of miR-221-regulated functions in breast cancer cells.

• Authors: Eleonora Brognara, Enrica Fabbri, Fabio Aimi, Alex Manicardi, Nicoletta Bianchi, Alessia Finotti, Giulia Breveglieri, Monica Borgatti, Roberto Corradini, Rosangela Marchelli, Roberto Gambari
• Journal: International journal of oncology (Int J Oncol) Vol. 41 Issue 6 Pg. 2119-27 (Dec 2012) ISSN: 1791-2423 [Electronic] Greece
• PMID: 22992757 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• MIRN221 microRNA, human
• MicroRNAs
• Peptide Nucleic Acids
• Cyclin-Dependent Kinase Inhibitor p27

Topics

• Base Sequence
• Breast Neoplasms (genetics, metabolism)
• Cell Line, Tumor
• Cyclin-Dependent Kinase Inhibitor p27 (genetics, metabolism)
• Female
• Gene Expression
• Gene Expression Regulation, Neoplastic
• Gene Order
• Humans
• MicroRNAs (genetics, metabolism)
• Peptide Nucleic Acids (chemical synthesis, metabolism)
• RNA Interference