Telomerase Inhibitors ‐ TMPyP4, BIBR 1532 and Imetelstat – Alter Adhesion Potential and Modify the Ability of Breast Cancer MCF7 and MDA‐MB‐231 Cells to form Spheroids

Background: /Objectives: Malignant neoplasms represent the most common diseases worldwide, and breast cancer is the most commonly diagnosed cancer type in the female population. One of the critical features of this cancer type is the ability to metastasize. This process is related to adhesion, migration, and invasiveness. As demonstrated, the catalytic telomerase subunit, hTERT, may control these processes. The expression and activity of telomerase in normal somatic cells are very low or absent, which makes it a universal and attractive target for cancer diagnostics and therapy; Methods: In this work, we assessed the influence of telomerase inhibitors TMPyP4, BIBR 1532, or imetelstat on the ability to form spheroids in MCF7 and MDA-MB-231 breast cancer cells. Cells of both lines were treated with specific compounds in concentrations: TMPyP4 - 5, 10, 20 µM; BIBR 1532 - 1, 5, 10 µM or imetelstat 1, 5, 10 µM for 72 hours. Cells were then trypsinized and applied to 96-well low-adhesive plates at 500 cells per well, followed by observation at different time intervals, i.e., 24, 48, and 72 hours; Results: As shown, the applied telomerase inhibitors influenced the ability of MCF7 and MDA-MB-231 breast cancer cells to form spheroids in a concentration- and incubation-time-dependent manner; Conclusions: Although the mechanism of this phenomenon has not been fully understood, it seems 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 cancer therapy.