Antitumor effect of afatinib, as a human epidermal growth factor receptor 2‐targeted therapy, in lung cancers harboring HER2 oncogene alterations

Abstract

Human epidermal growth factor receptor 2 (HER2) is a member of the HER family of proteins containing four receptor tyrosine kinases. It plays an important role in the pathogenesis of certain human cancers. In non‐small‐cell lung cancer (NSCLC), HER2 amplification or mutations have been reported. However, little is known about the benefit of HER2‐targeted therapy for NSCLCs harboring HER2 alterations. In this study, we investigated the antitumor effect of afatinib, an irreversible epidermal growth factor receptor (EGFR)–HER2 dual inhibitor, in lung cancers harboring HER2 oncogene alterations, including novel HER2 mutations in the transmembrane domain, which we recently identified. Normal bronchial epithelial cells, BEAS‐2B, ectopically overexpressing wild‐type HER2 or mutants (A775insYVMA, G776VC, G776LC, P780insGSP, V659E, and G660D) showed constitutive autophosphorylation of HER2 and activation of downstream signaling. They were sensitive to afatinib, but insensitive to gefitinib. Furthermore, we examined the antitumor activity of afatinib and gefitinib in several NSCLC cell lines, and investigated the association between their genetic alterations and sensitivity to afatinib treatment. In HER2‐altered NSCLC cells (H2170, Calu‐3, and H1781), afatinib downregulated the phosphorylation of HER2 and EGFR as well as their downstream signaling, and induced an antiproliferative effect through G1 arrest and apoptotic cell death. In contrast, HER2‐ or EGFR‐non‐dependent NSCLC cells were insensitive to afatinib. In addition, these effects were confirmed in vivo by using a xenograft mouse model of HER2‐altered lung cancer cells. Our results suggest that afatinib is a therapeutic option as a HER2‐targeted therapy for NSCLC harboring HER2 amplification or mutations.

Estimation of age-related DNA degradation from formalin-fixed and paraffin-embedded tissue according to the extraction methods

“…For example, comprehensive analysis of DNA alteration with next generation sequencing enables us to identify the novel genomic alterations in patients with cancer recurrence, which may provide more therapeutic targets. Indeed, various types of mutation, including epidermal growth factor receptor (EGFR) mutations and Human EGFR2 (HER2) mutations is the target of their inhibitors gefitinib, erlotinib, and afatinib (3,4).…”

The AXL receptor tyrosine kinase is associated with adverse prognosis and distant metastasis in esophageal squamous cell carcinoma

“…The viability was further inhibited to 27 % by combining 1 μM of lapatinib and 1 μM foretinib (Figure 3B). The efficacies of combined targeted therapies in ESCC cells were also examined in two other HER2-targeted drugs, afatinib [38] and AC480 (BMS599626) [39] (Figure 3C and 3D). Cytotoxicity of foretinib was also increased by treatment with either afatinib (Figure 3C) or AC480 (Figure 3D).…”

“…The HER2 inhibitors included lapatinib, afatinib [38] (Tovok, provided by Boehringer Ingelheim, Taiwan), and AC480 [39] (BMS599626, synthesized by Selleckchem, S1056). After incubation for 72 hours, cell survival was determined by MTT assay as described previously [40–41].…”

Afatinib as first‐line treatment for advanced lung adenocarcinoma patients harboring HER2 mutation: A case report and review of the literature

“…Afatinib exhibits antitumor efficacy by downregulating the phosphorylation of HER2 and EGFR, together with downstream signaling in HER2 mutant NSCLC. Moreover, it induces an anti‐proliferative effect through G1 arrest and apoptotic cell death . Increased HER2 phosphorylation, as well as increased sensitivity to afatinib, have also been observed in transfected Ba/F3 cells with HER2 (P780_Y781insGSP) mutation, indicating the possible treatment efficacy of afatinib …”