Fig. 2: SERPINA3 downregulation promotes AI-resistance in human ER+ breast cancer.

a The inhibit efficiencies of the siRNAs were detected by QPCR in MCF-7 cells. b MCF-7 cells were transfected with the siRNAs respectively and deprived of estrogen for 5 days. Cell proliferation was determined by counting. c T47D and MCF-7 cells were transfected with SERPINA3-targeting siRNAs and deprived of E2 or not for 7–10 days before crystal violet staining. d MCF-7 LTED and T47D LTED cells were transfected with SERPINA3-expressing plasmid and deprived of E2 or not for 7–10 days before crystal violet staining. e Downregulation of SERPINA3 in AI-resistant LTED lines were confirmed by western blot. According to the publicly available expression profiling data of clinical samples (f) GSE105777 (n = 172) and (g) GSE153470 (n = 112), SERPINA3 was downregulated in ER+ breast cancer after 2-week presurgical AI therapy. According to the data of 1057 breast cancer patients retrieved from TCGA database, low SERPINA3 expression correlates with poor survival in patients with both (h) luminal A and (i) luminal B subtypes of ER+. Data are representative of n = 3 biologically independent experiments and presented as mean ± SD; statistical significance is determined by unpaired Student’s t test (p < 0.05 *, p < 0.01 **, p < 0.001 ***); statistical significance of microarray gene expression data of paired samples from GSE153470, GSE105777 are determined by paired Student’s t test (p < 0.05 *, p < 0.01 **, p < 0.001 ***).