Abstract 326: Differences of drug sensitivities between 2-dimensional and 3-dimensional culture systems in triple negative breast cancer cell lines

Abstract

Abstract [BACKGROUND] In vitro chemosensitivity tests are not always consistent to clinical results (Hutchinston L et al., Nat Rev Clin Oncol. 2011), partly because of lacking extracellular matrix-cell interactions in 2-dimensional (2D) cell culture system (Antoni D et al., Int J Mol Sci. 2015). Three-dimensional cell culture (3D) system maintains cells with a higher degree of structural complexity and homeostasis, analogous to tissues and organs compared with 2D cell culture system. Thus, 3D cell culture system will be expected for alteration of the animal experiment in chemosensitivity test (Bokhari M et al., J Anat. 2007). Cytotoxic agents are crucial for treating triple negative breast cancer (TNBC).[AIM] To clarify differences of drug sensitivities between 2D and 3D culture in TNBC cell lines, we compared IC50s for Cisplatin (CDDP), Docetaxel (DTX), Epirubicin (EPI) and Bromodomain inhibitor (JQ1). [METHODS] Thirteen TNBC cell lines were examined; HCC1599, HCC1937, HCC38, MDA-MB-468, HCC1806, HCC70, MDA-MB-436, MDA-MB-231, Hs578T, BT549, MDA-MB-453, BT20, and HCC1395. For 2D culture, cells were plated on general 96 well cell culture plate for 24 hours. For 3D culture, cells were plated on the PrimeSurface® 96 well plate (SUMITOMO BAKELITE) for 72 hours. Then, those were incubated in media including CDDP, DTX, EPI or JQ1 for 72 hours. The cell viability was quantified using CellTiter-Glo 2.0 and CellTiter-Glo 3D cell viability Assay (Promega), respectively. [RESULTS] For CDDP, IC50s were highly correlated between 2D and 3D culture (r=0.928) . The mean of IC50 value showed higher in 3D culture (27.67±8.40μM) than 2D culture (12.86 ± 17.23μM). For EPI, the correlation was r=0.593. The mean value showed higher in 3D culture (1.41±1.30μM) than 2D culture (0.62±0.72μM). For DTX and JQ1, the mean values were 1.78 ± 2.05nM and 4.31 ±4.72μM in 2D culture, respectively. However, IC50 failed to be obtained in several TNBC cell lines (HCC1937, HCC38, HCC1806, Hs578T and HCC1395 for JQ1 and MDA-MB-436, MDA-MB-453 and BT20 for DTX) in 3D culture. [CONCLUSION] IC50 value was higher in 3D culture than in 2D culture for CDDP and EPI. The correlation of IC50s between 2D and 3D depended on drugs with the highest in CDDP. We are under investigation on reasons why sensitivity tests for DTX and JQ1 failed in 3D culture system. Citation Format: Masako Muguruma, Saeko Teraoka, Kana Miyahara, Ai Ueda, Takahiko Kawate, Takashi Ishikawa. Differences of drug sensitivities between 2-dimensional and 3-dimensional culture systems in triple negative breast cancer cell lines [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 326.