The Effect of MDA-MB-231 triple negative breast cancer cell sub-lines interaction on resistance to chemotherapy

Abstract

Triple negative breast cancer (TNBC) is one of the most aggressive and highly heterogeneous tumors with morphologically distinct subtypes[1]. This type of tumor is highly resistant to chemotherapy and it is related to the phenotypic heterogeneity of tumor cell populations. Scientists found that in genetically homogeneous cell populations, the phenotypic heterogeneity is frequently observed in in vitro cell cultures even in a controlled environment [2]. Identifying the differences between populations and their response to anticancer drugs could help to predict the tumor resistance to chemotherapy [3]. The aim of our study was to isolate phenotypically different single-cell-derived clones (sub-lines) from the commercial MDA-MB-231 cell line. Materials and methods. Sub-lines isolation was performed by multiple dilutions of the cell suspension to microplate. Sub-lines have been characterized by the expression of the CD133 receptor (immunofluorescence staining), their susceptibility and 2D cell interaction influence to anticancer drugs doxorubicin (DOX) and paclitaxel (PTX) (MTT assay), ability to migrate (wound healing assay). Influence of cell sub-lines interaction on spheroid size, shape and compactness were evaluate by microscopy, spheroids were formed by 3D bioprinting method. Results. The expression of the CD133 receptor was more than 30% higher in the sub-line E7 compared to the MDA-MB-231 cell line. The susceptibility of cell sub-lines to the tested anticancer drugs was different. Sub-line H2 was the most resistant to DOX (EC50 value after 72 hours was 158.7 ± 33.3 μM, whereas EC50 value for MDA-MB-231 cell line was 140.0 ± 23.2 μM). All sub-lines were from 2 to 4 times more resistant to PTX compared to the parent MDA-MB-231 cell line. The results from the cell migration study showed that migration rate of sub-lines B7, F7, G5 and H2 was from 4 to 8 times higher in comparison to MDA-MB-231 line. Different resistance of sub-lines and their mixtures was