Fig 2: Influence of the ABCB1 inhibitors elacridar and tariquidar in combination with DTX on cellular viability and clonogenic survival of DU145 and PC-3 DTXR cells compared to CTRL cells. (a) DU145 and PC-3 CTRL and DTXR cells were treated with a serial dilution of DTX in the presence or absence of an ABCB1 inhibitor (50 nM elacridar or tariquidar). After treatment, the metabolic activity was measured by the WST-1 assay and IC50 values for DTX were calculated. The adjacent graphs to the right depict IC50 values calculated from individual experiments. Ela.: elacridar, Tari.: tariquidar. (b) CTRL and DTXR cells were treated with either 50 nM elacridar or 10 nM DTX alone or with a combination of both. Thereafter, cell colony formation assays were seeded and cell colonies were counted after 10–12 d. Exemplary colonies are shown in the right panels. All data were normalized to the indicated control (black line). Data are depicted as mean ± SD of four to six independent biological replicates. (a) Non-paired t-test with Welch’s correction for comparison of two treatment groups and (b) one-sample t-test for comparison to the untreated control: ** p < 0.01, *** p < 0.001, ns: not significant.

Fig 3: Biotinylated protein from TNBC cells and MCF10A cells show that GABAAR α1 subunit is localized on the cell surface. (A) GABAA α1 subunit protein expression in whole cell samples (input) versus biotinylated samples (pulldown) in TNBC cells and MCF10A cells showing that GABAAR α1 subunits are localized on the cell surface, n = 3. GAPDH is a cytosolic marker shown as loading control. ABCB1 protein expression was used as a positive control to confirm the detection of a membrane-bound protein in the samples. (B) Corresponding densitometry of the ratio of pulldown to input samples across MCF10A and TNBC cell lines. * represent significance compared to MCF10A. Data are presented as mean±SE, *p < 0.05 (ANOVA).

Fig 4: (A) Comparison of the levels of P-gp (determined by Western Blot) in the sham-operated rats and two groups of implant-operated animals: one with no drug treatment (W/T) and the other given mifepristone/temozolomide (Mif/Tz) at 5 weeks post-surgery (corresponding to the end of the 3-week drug treatment), and 9, 14 weeks (corresponding to 4 and 9 weeks after the end of drug treatment), h.e., high exposure; l.e., low exposure. (B) The densitometer analysis (n = 3). Data represent the mean ± SD of three independent experiments. *Significant difference (p < 0.05) between the Mif/Tz rats at 5 and 14 weeks.

Fig 5: The development of a CML cell line with resistance to imatinib treatment. (A) Percentage of cell viability after applying imatinib alone (at distinct concentrations), considering CML cells sensitive (K562) and resistant (K562-RI) to this drug. The table denotes the IC50 of imatinib in each cell line and the relative resistance of K562-RI (calculated as the IC50 of K562-RI divided by that of K562). (B) P-gp expression levels in the K562 and K562-RI cell lines, based on Western blot and its densitometric analysis (β-actin was the load control); three Western blots from three independent experiments were used for densitometric analysis. (C) Analysis of P-gp evaluated by the immunofluorescence assay (the nuclei were visualized with DAPI). The mean fluorescence intensity was quantified by counting P-gp-positive cells from three independent experiment. Scale bars: 20 μm. (D) Representative histograms of the fluorescence of uptake of doxorubicin in the K562 and K562-RI cell lines. The empty histograms depict the control cells without doxorubicin. Data are expressed as the relative mean fluorescence intensity (RMFI) ± SEM of three independent experiments. The values of k562-RI were normalized with respect to K562. Statistical analysis was performed by comparing K562-RI to the parental cell line. * p < 0.05; Student’s t-test.