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. 2023 Dec 19;13:22648. doi: 10.1038/s41598-023-49646-5

Figure 5.

Figure 5

Analysis of changes in protein expression and cell cycle distribution after drug treatment in parental and trastuzumab-resistant (TR) cell lines. Trastuzumab, trastuzumab deruxtecan (T-DXd), and SN-38 were used at 200 μg/mL, 10 μg/mL, and 1 nM, respectively. (a) After 72 h of drug treatment, the expression level of HER2 on the cell surface was quantified by flow cytometry (mean fluorescence intensity, MFI). Three breast cancer cell lines (SK-BR-3, ZR-75–1, and MCF7) were used as controls of HER2 expression. (b) Top row: change in expression of pAKT-Ser473, pAKT-Thr308, AKT, pERK-Thr204, and ERK after 4 h of drug treatment; bottom row: expression of pH2A.X-Ser139, cleaved PARP, and PCNA after 72 h of drug treatment. α-Tubulin was used as the loading control. The blots were cut prior to hybridization with antibodies. The uncropped version of the western blots is reported in Supplementary Fig. S6. (c) Parental and TR cell lines of YCC-33, NCI-N87, and SNU-216 were treated with trastuzumab (100 μg/mL) or T-DXd (10 μg/mL) for 24 h, and YCC-38 and YCC-38TR were treated for 72 h. Cell cycle distribution was analyzed by flow cytometry. Error bars, SD.