Abstract 2888: Reversible and dose-dependent suppression of motility of human breast cancer cells with ONC201 and/or TR57 in culture

The cytotoxicity and cytostatic effects of imipridone family drugs ONC201 and its analog TR57 (Madera, USA) in variety of cultured breast cancer cell line (estrogen dependent BT474) was manifested through induction of ISR (Integrated Stress Response), UPRER and UPRMT. The major consequences of drug treatment are inhibition of proliferation and mitochondrial structural and functional damage(s). Our preliminary data demonstrated that 24 h exposure of BT474 leads to dysregulation and suppression in mitochondrial Ca2+ uptake and Ca2+ capacity (Odinokova et al., 2021). In the present work, we extend our study to include the effect of these drugs on the rate of migration intact and treated cells in culture. Treatment of BT474 cells in culture for 24h resulted in decreased motility of cells from 17 ± 2 µm/h in the absence of the drugs to 5 ± 1 µm/h and to 3±1 µm/h in cells treated with 10µM of ONC201 or 50nM of TR57 (n=5). This suppression was fully reversible and removal of drugs for 120h resulted in time dependent restoration of the initial motility of BT474 cells, and TR57 caused larger inhibitory effect on motility as compared with ONC201. Buffering of extracellular Ca2+ with 5 mM EGTA or intracellular Ca2+ with 10 µM BAPTA, 30 min suppressed motility of cells (19 ± 2 µm/h vs 6 ± 1 µm/h). Gd3+, selective blocker of store operated Ca2+ entrance (SOCE) pathway at concentration of 10 µM suppressed the motility of BT474 cells, and rate of migration changed for from 16 ± 2 µm/h in control to 7± 2 µm/h, in Gd3+ treated cells. In line with our preliminary data, taken together these data indicate that ONC201 and/or TR57 induced dysfunction in mitochondrial Ca2+ homeostasis, which translates into the suppression of the migration of human breast cancer cells in culture. Support of Funding Information: Russian Science Foundation № 19-75-20145 Citation Format: Yana Evstratova, Margarita Kobyakova, Irina Odinokova, Alexander Stolyarov, Artyom Mishukov, Lee M. Graves, Ekhson Holmuhamedov. Reversible and dose-dependent suppression of motility of human breast cancer cells with ONC201 and/or TR57 in culture [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2888.