Figure 1.

Breast cancer cells with elevated protein arginine methyl transferase 1 (PRMT1) expression levels are associated with therapeutic resistance to olaparib. (A) Correlations of sensitivities to olaparib with transcriptome-wide mRNA expression in breast cancer cell lines according to the Cancer Cell Line Encyclopedia (CCLE) datasets and the Genomics of Drug Sensitivity in Cancer (GDSC) database. PRMT1 is labeled with the red dot. (B) Box plot with Tukey’s test whiskers showing PRMT1 expression levels in olaparib-susceptible and -resistant breast cancer cell lines according to CCLE breast cancer dataset along with GDSC database. ** p < 0.01 was considered statistically significant and determined by using unpaired t tests. (C) Scatterplot of PRMT1 expression and half-maximal inhibitory concentration (IC₅₀) of olaparib in breast cancer cell lines. Correlation coefficient was obtained by using Pearson’s test. Unit of PRMT1 mRNA was log2-normalized RNA expression. (D) Bar charts showing that PRMT1 has the strongest correlation with olaparib resistance among PRMT subtypes in breast cancer cell lines. (E) Correlations of PRMT1 and 200 drug sensitivities in breast cancer cell lines according to GDSC database and CCLE dataset. Red-labeled drugs are poly(ADP-ribose) polymerase inhibitors. (F) Box plots with PRMT1 expression levels among four conventional chemotherapy drugs (oxaliplatin, doxorubicin, cisplatin, and epirubicin) for drug-susceptible and -resistant breast cancer cell lines. ns, not significant. (G) Scatterplots of Pearson’s correlation analysis of PRMT1 and IC₅₀ of four chemotherapy drugs in breast cancer cell lines.