Fig. 5: Zanidatamab promotes Ab internalization, surface and total HER2 downregulation and signal inhibition in SK-BR-3 and NCI-N87 cells. | Nature Communications

Fig. 5: Zanidatamab promotes Ab internalization, surface and total HER2 downregulation and signal inhibition in SK-BR-3 and NCI-N87 cells.

From: An anti-HER2 biparatopic antibody that induces unique HER2 clustering and complement-dependent cytotoxicity

Fig. 5: Zanidatamab promotes Ab internalization, surface and total HER2 downregulation and signal inhibition in SK-BR-3 and NCI-N87 cells.The alt text for this image may have been generated using AI.

a Zanidatamab showed increased receptor-mediated internalization compared to trastuzumab or pertuzumab (15 min to 6 h), measured by high content microscopy (n = 3 independent experiments). (Right) Zanidatamab conferred significantly greater receptor-mediated internalization compared to trastuzumab or pertuzumab (adjusted p < 0.001) in SK-BR-3 cells or NCI-N87 cells (24 h), measured by flow cytometry (n = 3 SK-BR-3 or n = 4 NCI-N87 independent experiments). A two-way ANOVA controlling for experiment with Bonferroni correction for multiple comparisons was performed, data normalized to trastuzumab, df = 3 for ANOVA and df = 4 for t-tests. b Zanidatamab showed significantly greater surface HER2 downregulation compared to trastuzumab (p = 0.001) and pertuzumab (p < 0.001) in SK-BR-3 cells and compared to trastuzumab (p = 0.04) and pertuzumab (p = 0.02) in NCI-N87 cells, evaluated by flow cytometry. Tras + pert mediated significantly greater HER2 downregulation compared to zanidatamab (p = 0.001) in SK-BR-3 cells (n = 3 SK-BR-3 or n = 4 NCI-N87 independent experiments, two-sample two-sided t tests with Bonferroni correction for multiple comparisons, df = 4). c Zanidatamab reduced total HER2 (24 h) when compared to untreated cells (adjusted p = 0.08, SK-BR-3; adjusted p = 0.06, NCI-N87). d Zanidatamab mediated inhibition of pHER2, pHER3, pEGFR, pAKT and pERK (adjusted p = 0.06) in NCI-N87 cells compared to untreated cells (24 h). e Zanidatamab mediated inhibition pHER3 (adjusted p = 0.047) and pAKT (adjusted p = 0.082) in SK-BR-3 cells compared to untreated cells (15 min), evaluated by immunoblotting. In c (df = 2), d (df = 2) and e (df = 3), evaluation performed by immunoblotting. In c and d (n = 3) and in e (n = 4) independent experiments, one sample two-sided t-test compared to untreated cells value of 100% with p values adjustment using Benjamini & Hochberg false discovery, comparisons with adjusted p values < 0.1 shown. Data in a (left) is mean ± SEM, a (right), b–e, mean ± 95% CI. Gating strategy for a (right) and b is shown in Supplementary Fig. 12e, f. Source data are provided in the Source Data file.

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