Abstract 1119: Non-adherent breast and non-small-cell lung cancer cell cultures as a promising CTCs’ model for evaluation of the anti-tumor effects of artesunate
Authors: Pantazaka Evangelia , Graikioti Dafni , Athanassopoulos Constantinos M. , Kallergi Galatea 
Published: June 2022

Abstract
Background: Artesunate (AS), besides being widely used as an antimalarial agent, has been also suggested to exert anti-tumor activity in a plethora of cancer types, including breast and lung cancer. Recently, AS has been shown to inhibit the expression of JunB, which is associated with metastatic progression. The aim of this study is to examine the effect of AS on the viability of both adherent and non-adherent (resembling circulating tumor cells; CTCs) breast and lung cancer cell cultures.
Methods: Prevention of cell attachment and establishment of the CTCs’ model was achieved via polyHEMA [poly(2-hydroxyethyl methacrylate)] treatment. Viability of adherent and non-adherent MDA-MB-231 (triple negative breast cancer) and H1299 (non-small-cell lung cancer) cells was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-dimethyltetrazolium bromide (MTT) assay, 48 h following treatment with different concentrations of AS (3 μM to 100 μΜ) in serum starvation conditions. Cell migration was examined using the wound healing assay.
Results: Optimization involving the duration (20 min vs. overnight) and concentration (10 mg/ml) of polyHEMA coating, as well as the duration of AS treatment (24 h vs. 48 h) were performed. 5-fluorouracil was used as a positive control. AS decreased viability of both cell lines in a concentration-dependent manner with comparable IC50, whether being adherent (pIC50 = 4.6 ± 0.1 and 5.1 ± 0.1 for MDA-MB-231 and H1299, respectively; n = 8) or non-adherent (pIC50 = 4.5 ± 0.1 and 4.9 ± 0.1 for MDA-MB-231 and H1299, respectively; n =8). AS (10 μΜ, 48 h) inhibited proliferation of both adherent MDA-MB-231 (34% ± 5, n = 8) and H1299 (57% ± 4, n = 8) cells. Interestingly, the effect of AS on MDA-MB-231 and H1299 non-adherent cultures was less prominent (15% ± 6 and 26% ± 6, P&lt;0.001, respectively; n = 8), demonstrating resistance to AS. Furthermore, AS (10 μM, 48 h) decreased cell migration, an effect which was more pronounced in H1299 cells.
Conclusions: Evidently, non-adherent, free-floating cells seem to respond differently to AS compared to their attached counterparts. These results suggest that antitumor agents might exert different effects in CTCs compared to adherent tumor cells.
Acknowledgements: This research has been co-financed by the European Union and Greek national funds through the Operational Program Competitiveness, Entrepreneurship and Innovation, under the call RESEARCH - CREATE - INNOVATE (project code: T2ΕΔΚ-01562).
Citation Format: Evangelia Pantazaka, Dafni Graikioti, Constantinos M. Athanassopoulos, Galatea Kallergi. Non-adherent breast and non-small-cell lung cancer cell cultures as a promising CTCs’ model for evaluation of the anti-tumor effects of artesunate [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1119.