Skip to main content
. 2021 Jul 15;11:697950. doi: 10.3389/fonc.2021.697950

Figure 2.

Figure 2

ABCB1 is essential to chemoresistance in breast cancer. (A) Expression of ABCB1 in breast cancer samples collected pre- and postchemotherapy in the dataset GSE87455. (B) Representative images of IHC staining for ABCB1 in chemoresistant and chemosensitive breast cancer samples. (C) Correlation between the pCR rate and ABCB1 expression in breast cancer samples obtained from 67 patients. (D, E) Protein (D) and mRNA (E) levels of ABCB1 in MCF7 and MCF7/DOX cells determined by Western blotting and qPCR. (F, G) Protein (F) and mRNA (G) levels of ABCB1 in MCF7 cells transfected with an empty vector or ABCB1 vector determined by Western blotting and qPCR. (H) Survival rate and IC50 of MCF7 cells transfected with an empty vector or a STAT5a vector after treatment with DOX for 48 h determined by a CCK8 assay. (I) Representative images and quantification of colonies formed by MCF7 cells transfected with the empty vector or ABCB1 vector in medium containing DOX. (J, K) Protein (J) and mRNA (K) levels of ABCB1 in MCF7/DOX cells transfected with scramble siRNA or ABCB1-targeting siRNA detected by Western blotting and qPCR. (L) Survival rate and IC50 of MCF7/DOX cells transfected with scramble siRNA or ABCB1-targeting siRNA after treatment with DOX for 48 h determined by a CCK8 assay. (M) Representative images and quantification of colonies formed by MCF7/DOX cells transfected with scramble siRNA or ABCB1-targeting siRNA in medium containing DOX. (N, O) Expression of apoptosis markers in MCF7 cells transfected with the empty vector or ABCB1 vector (N) and in MCF7/DOX cells transfected with scramble siRNA or ABCB1-targeting siRNA in the presence of DOX (O). (P, Q) Representative images (P) and quantification (Q) of the accumulation of DOX in MCF7 and MCF7/DOX cells after treatment with DOX. (R, S) Representative images (R) and quantification (S) of the accumulation of DOX in MCF7/DOX cells transfected with scramble siRNA or ABCB1-targeting siRNA after DOX treatment. *p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001.