Fig. 1.

The synergistic effect of olaparib and palbociclib in BRCA^mut/TNBCs. a The IC50 of olaparib and palbociclib in a panel of 8 TNBC cell lines. b The IC50 of olaparib was measured in BRCA^mut cell line with 1 μM palbociclib or not. When detecting the IC50 of olaparib in cells treated with 1 μM palbociclib, the control group used for normalization was with 1 μM palbociclib but not olaparib. c Inhibition rate and combination index (CI) in (upper) MDA-MB-436 and (lower) HCC1937 cells at different drug concentrations (μM). The colour represents the degree of inhibition, and the displayed value represents the CI. Olaparib was diluted 2/3 times from left to right, and the concentration of palbociclib (μM) from top to bottom was 25, 20, 15, 10, 5, 2.5, and 0. d Cell proliferation curve of olaparib or palbociclib alone or in combination in (upper) the PARPi-sensitive cells MDA-MB-436 and (lower) PARPi-resistant cells HCC1937. c (olaparib) = 5 μM, c (palbociclib) = 5 μM. e Changes in relative cell numbers and cell morphology after 3 days of single-agent or combined treatment in MDA-MB-436 and HCC1937 cells. f Transwell migration assay in MDA-MB-436 and HCC1937 cells pretreated with drug as indicated for 3 days. The migration times of HCC1937 and MDA-MB-436 cells were 18 h and 24 h, respectively. g Apoptosis evaluation after 3 days of single-agent or combined treatment in MDA-MB-436 and HCC1937 cells. c (olaparib) = 15 μM, c (palbociclib) = 15 μM. Student’s t-test; ***p < 0.001, **p < 0.01, *p < 0.05; ns, not significant. The data are presented as the means ± SEMs. Ola: Olaparib; Palb: Palbociclib