The Anti-HER3 mAb Seribantumab Effectively Inhibits Growth of Patient-Derived and Isogenic Cell Line and Xenograft Models with Oncogenic
NRG1 Fusions.
Clin Cancer Res 2021;
27:3154-3166. [PMID:
33824166 DOI:
10.1158/1078-0432.ccr-20-3605]
[Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 01/02/2021] [Accepted: 03/19/2021] [Indexed: 12/17/2022]
Abstract
PURPOSE
Oncogenic fusions involving the neuregulin 1 (NRG1) gene are found in approximately 0.2% of cancers of diverse histologies. The resulting chimeric NRG1 proteins bind predominantly to HER3, leading to HER3-HER2 dimerization and activation of downstream growth and survival pathways. HER3 is, therefore, a rational target for therapy in NRG1 fusion-driven cancers.
EXPERIMENTAL DESIGN
We developed novel patient-derived and isogenic models of NRG1-rearranged cancers and examined the effect of the anti-HER3 antibody, seribantumab, on growth and activation of signaling networks in vitro and in vivo.
RESULTS
Seribantumab inhibited NRG1-stimulated growth of MCF-7 cells and growth of patient-derived breast (MDA-MB-175-VII, DOC4-NRG1 fusion) and lung (LUAD-0061AS3, SLC3A2-NRG1 fusion) cancer cells harboring NRG1 fusions or NRG1 amplification (HCC-95). In addition, seribantumab inhibited growth of isogenic HBEC cells expressing a CD74-NRG1 fusion (HBECp53-CD74-NRG1) and induced apoptosis in MDA-MB-175-VII and LUAD-0061AS3 cells. Induction of proapoptotic proteins and reduced expression of the cell-cycle regulator, cyclin D1, were observed in seribantumab-treated cells. Treatment of MDA-MB-175-VII, LUAD-0061AS3, and HBECp53-CD74-NRG1 cells with seribantumab reduced phosphorylation of EGFR, HER2, HER3, HER4, and known downstream signaling molecules, such as AKT and ERK1/2. Significantly, administration of seribantumab to mice bearing LUAD-0061AS3 patient-derived xenograft (PDX) and OV-10-0050 (ovarian cancer with CLU-NRG1 fusion) PDX tumors induced regression of tumors by 50%-100%. Afatinib was much less effective at blocking tumor growth.
CONCLUSIONS
Seribantumab treatment blocked activation of the four ERBB family members and of downstream signaling, leading to inhibition of NRG1 fusion-dependent tumorigenesis in vitro and in vivo in breast, lung, and ovarian patient-derived cancer models.
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