BRCA1-IRIS overexpression promotes EMT and invasion in HME cells, while inactivation suppresses them in TNBC cells. (A) Representative images showing the invasion ability of MDA-MB-231 (A and H) and MDA-MB-468 (D and K) cells through matrigel-coated Boyden chambers and the significant retardation of this invasion ability following BRCA1-IRIS silencing in MDA-MB-231 (B and I) and MDA-MB-468 (E and L) or BRCA1-IRIS inactivation using IRIS peptide in MDA-MB-231 (C and J) and MDA-MB-468 (F and M) cells on day 7. Scale bars in A-F and H-M = 1,000 μm. Quantitative analysis of invasive ability of the indicated cells shown as cells travelled to the other side of the transwells (G) or jumped to the lower well of the Boyden chamber (N). (O) The expression of the indicated EMT biomarkers in HME or BRCA1-IRIS overexpressing HME cells as well as MDA-MB-231 or MDA-MB-468 cells expressing or silenced from BRCA1-IRIS. Please note that BRCA1-IRIS and H2B blots used are the same as those used in Figure 4G. The expression of the indicated EMT/invasion biomarkers in HME (P1, Q1, R1, and S1), BRCA1-IRIS-overexpressing HME (P2, Q2, R2 and S2), MDA-MB-468 (P3, Q3, R3 and S3) or MDA-MB-468 silenced from BRCA1-IRIS (P4, Q4, R4 and S4) cells. Scale bars in P1-P4 and S1-S4 = 20 μm, and in Q1-Q4 and R1-R4 = 50 μm. EMT, epithelial to mesenchymal transition; HME, human mammary epithelial cells; TNBC, triple negative breast cancer.