Telomerase inhibitors - TMPyP4, BIBR 1532 and imetelstat - alter the adhesion potential of breast cancer MCF7 and MDA-MB-231 cells that leads to impaired ability to form spheroids.

We assessed the influence of telomerase inhibitors TMPyP4, BIBR 1532, or imetelstat on the ability of MCF7 and MDA-MB-231 breast cancer cells to form spheroids. TMPyP4 significantly impaired the adhesion potential and ability of both cell lines to form spheroids. BIBR 1532 treatment did not show any effect in MCF7 while it showed some effect in MDA-MB-231 cells, although this effect was less extensive comparing to TMPyP4. Application of Imetelstat provoked a dispersion effect in both cell lines but more single, separated distant cells were observed. Molecular docking and molecular dynamic studies showed that both BIBR 1532 and TMPyP4 exhibited affinity toward the structure of a G-quadruplex of human telomeric RNA (TERRA2 G4s) and the catalytic subunit of telomerase, hTERT. We showed that the use of telomerase expression/activity inhibitors to reduce the adhesive capacity and metastatic potential of breast cancer cells may play a significant role in anticancer strategy.