Insights into ErbB signaling from the structure of the ErbB2-pertuzumab complex

Abstract

We have determined the 3.2 A X-ray crystal structure of the extracellular domain of the human epidermal growth factor receptor 2 (ErbB2 or HER2) in a complex with the antigen binding fragment of pertuzumab, an anti-ErbB2 monoclonal antibody also known as 2C4 or Omnitarg. Pertuzumab binds to ErbB2 near the center of domain II, sterically blocking a binding pocket necessary for receptor dimerization and signaling. The ErbB2-pertuzumab structure, combined with earlier mutagenesis data, defines the pertuzumab residues essential for ErbB2 interaction. To analyze the ErbB2 side of the interface, we have mutated a number of residues contacting pertuzumab and examined the effects of these mutations on pertuzumab binding and ErbB2-ErbB3 heterodimerization. We have also shown that conserved residues previously shown to be necessary for EGF receptor homodimerization may be dispensible for ErbB2-ErbB3 heterodimerization.

Suppression of breast cancer cell growth by a monoclonal antibody targeting cleavable ErbB4 isoforms

“…The anti-ErbB1 antibody cetuximab inhibits ligandmediated phosphorylation of ErbB1 by directly competing with ligand binding to ErbB1 (Prewett et al, 1998). The anti-ErbB2 mAb pertuzumab sterically hinders recruitment of ErbB2 into ErbB/ligand complexes An isoform-specific anti-ErbB4 antibody M Hollmén et al affecting the formation and activation of ErbB2-containing dimers (Agus et al, 2002;Franklin et al, 2004). However, our preliminary in vitro experiments with recombinant proteins suggest that mAb 1479 does not compete with NRG binding to ErbB4 or interfere with NRG-induced ErbB4 dimerization.…”

“…An isoform-specific anti-ErbB4 antibody M Hollmén et al from which the clinically developed pertuzumab is a humanized derivative (Franklin et al, 2004). Moreover, mAb 1479 significantly suppressed the anchorageindependent growth of both T-47D (Po0.001) and MCF-7 (P ¼ 0.002) cells in soft agar colony formation assays (Figure 6b and c).…”

The ERBB3 receptor in cancer and cancer gene therapy

“…Part of the reason for this may be amino acid changes in loops adjacent to domain II dimerization arms; disulfide-bonded module 6 is utilized in EGFR dimerization, 54 whereas for ERBB2/ERBB3 heterodimer formation module 7 plays the key role. 55 (6) ERBB3 does however form self-oligomers; both the purified extracellular domain of ERBB3 and the full length protein expressed in insect cells underwent self-oligomerization at low concentrations, comparable to those normally seen on cell surfaces. 56 This oligomerization was destabilized and reduced in the presence of NRG ligand.…”

“…114 A site-specific mutagenesis study identified ERBB2 sites L295 and H296 as critical to ERBB2/ERBB3 heterodimerization in response to NRG. 55 A monoclonal antibody to the EGFR stimulated the growth of NSCLC line PC-14 by enhancing ERBB2/ERBB3 heterodimerization, possibly by blocking hetero-dimerization of EGFR with ERBB2 or ERBB3. 115 Herstatin, a naturally occurring ERBB2 inhibitor, prevented transactivation of ERBB3 in response to NRG in the context of CHO cells transfections.…”

The epidermal growth factor receptor family: Biology driving targeted therapeutics

“…Since the structural basis for ErbB dimerization has been elucidated, a second ErbB2-targeting mAb, pertuzumab, has been developed that binds to the dimerization interface of the ErbB2 ECD [169]. Pertuzumab potentially interferes with ErbB2 dimerization providing a rational basis for inhibiting ErbB2-mediated oncogenic signaling.…”