Synergistic effects of the combined treatment of U251 and T98G glioma cells with an anti‑tubulin tetrahydrothieno[2,3‑c]pyridine derivative and a peptide nucleic acid targeting miR‑221‑3p

Abstract

In the development of novel and more effective anticancer approaches, combined treatments appear to be of great interest, based on the possibility of obtaining relevant biological or therapeutic effects using lower concentrations of single drugs. Combination therapy may prove to be of utmost significance in the management of glioblastoma (GBM), a lethal malignancy that accounts for 42% of cancer cases of the central nervous system, with a median survival rate of 15 months. As regards novel therapeutic approaches, the authors have recently demonstrated that peptide nucleic acids (PNAs) that target microRNA (miRNA/miR)-221 are very active in inducing the apoptosis of glioma cells. Furthermore, in a recent study, the authors described two novel series of tubulin polymerization inhibitors based on the 4,5,6,7-tetrahydrothieno[2,3-c]pyridine and 4,5,6,7-tetrahydrobenzo[b]thiophene scaffold, which exerted a potent anti-proliferative effect on a variety of tumor cell lines. The present study aimed to verify the activity on glioblastoma cancer cell lines of one of the most active compounds tested, corresponding to 2-(3' , 4' , 5'-trimethoxyanilino)-3-cyano/alkoxycarbonyl-6-substituted-4 5,6,7-tetrahydrothiene[2,3-c] pyridine (compound 3b), used in combination with an anti-miR-221-3p PNA, already demonstrated to be able to induce high levels of apoptosis. To the best of our knowledge, the results obtained herein demonstrate for the first time a 'combination therapy' performed by the combined use of a PNA targeting miR-221 and the tetrahydrothiene[2,3-c]pyridine derivative 3b, supporting the concept that the combined treatment of GBM cells with a PNA against a specific upregulated oncomiRNA (in the present study a PNA targeting miR-221-3p was used) and anti-tubulin agents (in the present study derivative 3b was used) is an encouraging strategy which may be used to enhance the efficacy of anticancer therapies and at the same time, to reduce side-effects.

Synergistic Effects of A Combined Treatment of Glioblastoma U251 Cells with An Anti-miR-10b-5p Molecule and An AntiCancer Agent Based on 1-(3′,4′,5′-Trimethoxyphenyl)-2-Aryl-1H-Imidazole Scaffold

“…We have already published two studies on synergistic effects of miRNA inhibitors on GBM cell lines when they are co-administered with anticancer agents [ 13 , 19 ]. In the first study, a peptide-nucleic acid (PNA) targeting miR-221-3p was co-administered with a tubulin inhibitor different from that employed in the present study [ 19 ]. In the second, a PNA targeting miR-15b-5p was co-administered with sulforaphane [ 13 ].…”

“…Data were collected and analyzed using Bio-Rad CFX Manager Software (Bio-Rad, Hercules, CA, USA). The relative gene expression was calculated using 2 −ΔΔCt method, and data normalization was performed using U6 snRNA and hsa-let-7c as reference [ 18 , 19 ].…”

“…After 24 h of incubation at −20 °C, fixed cells were washed in PBS and resuspended in 200 µL of Muse ® Cell Cycle Reagent and incubated for 30 min at room temperature protected from light. Finally, the cell suspension was transferred into a new tube and the samples analyzed by flow cytometry using Guava ® Muse ® Cell Analyzer (Luminex Corp., Austin, TX, USA) [ 19 ].…”

“…After 25 min of incubation, 150 μL of 7-AAD working solution was added to each tube and incubated for 5 min before reading the samples. Samples were then analyzed using Guava ® Muse ® Cell Analyzer (Luminex Corp.) and data acquired utilizing the Caspase-3/7 Software Module (Luminex Corp.) [ 19 , 60 ].…”

“…Therefore, the PNA-a15b might be proposed in “combo-therapy” associated with SFN. Overall, this study suggests the feasibility of using combined treatments in which chemical bioactive agents directed against selected tumor-associated pathways might be administered together with antisense biomolecules targeting oncomiRNAs [ 14 , 15 , 16 , 17 , 18 , 19 ].…”