Figure 4

Influence of paclitaxel and SF in chemically defined media of breast cancer cells. (a) Graphical plot of MTT assay and comparison of relative cell viability between different doses of paclitaxel ranging from 1 nM to 100 µM for 48 h with control cells in chemically defined media of TNBCs. The cell viability is unchanged over a wide range of concentrations indicating cancer cells are resistant towards paclitaxel. (b) Flow cytometry results of Annexin V/PI staining, analysis of CD44⁺/CD24⁻ breast cancer stem cells (CSCs), multi drug resistance protein 1 (MDR1), programmed death ligand-1(PD-L1) expressing TNBCs treated with 1.7 µM paclitaxel after 48 h compared to control cells in chemically defined media of TNBCs. Though paclitaxel reduces MDR1+ and PDL1+ markers the cancer cells are still resistant to paclitaxel. The reduction in the markers is not nearly as much as the reduction caused by SF (see Fig. 2g). (c) Histogram plot of MTT results of SF 50 mg/ml, SF 70 mg/ml, Paclitaxel (1.6 µM, and 0.17 nM) and combinations of 50 mg/ml with 1.6 µM, 70 mg/ml with 1.6 µM and 0.17 nM on TNBCs after 48 h in 2D culture conditions compared to control. All data with SF of 70 mg/ml was statistically lower than when SF 50 mg/ml was used and resulted in significant decrease in the population of the resistance cancer cells. Such additions could be an add-on therapy to chemotherapy. All graphical plots are mean ± SD values and differences between control and treatment concentrations were considered statistically significant for p value < 0.05 and is represented by (*).