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![Peptide nucleic acid-based targeting of microRNAs: possible therapeutic applications for glioblastoma](https://image.oaes.cc/911a7f86-9093-4a07-b510-f574834a61bc/3148.fig.5.jpg)
Figure 5. A: Structure of the macrocyclic multivalent tetraargininocalix[4]arene 1 used as non-covalent vector for anti-miRNA PNAs; B,C: Effects of compound 1 on morphology of U251 glioma cells: lack of cytotoxic effects. D. Effects of free PNA (a221-PNA) and a221-PNA delivered with compound 1 on miR-221-3p in treated U251 cells. Inhibition of miR-221-3p expression is obtained only when a221-PNA is vehiculated by compound 1. Modified from Gasparello et al.[125]