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Supplementary Data from Insulin-Like Growth Factor-1 Receptor Inhibition Induces a Resistance Mechanism via the Epidermal Growth Factor Receptor/HER3/AKT Signaling Pathway: Rational Basis for Cotargeting Insulin-Like Growth Factor-1 Receptor and Epidermal Growth Factor Receptor in Hepatocellular Carcinoma

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posted on 2023-03-31, 15:47 authored by Christèle Desbois-Mouthon, Aurore Baron, Marie-José Blivet-Van Eggelpoël, Laetitia Fartoux, Corinne Venot, Friedhelm Bladt, Chantal Housset, Olivier Rosmorduc
Supplementary Data from Insulin-Like Growth Factor-1 Receptor Inhibition Induces a Resistance Mechanism via the Epidermal Growth Factor Receptor/HER3/AKT Signaling Pathway: Rational Basis for Cotargeting Insulin-Like Growth Factor-1 Receptor and Epidermal Growth Factor Receptor in Hepatocellular Carcinoma

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ARTICLE ABSTRACT

Purpose: The insulin-like growth factor (IGF) signaling axis is frequently dysregulated in hepatocellular carcinoma (HCC). Therefore, we investigated whether the specific targeting of the IGF type 1 receptor (IGF-1R) might represent a new therapeutic approach for this tumor.Experimental Design: Total and phosphorylated levels of IGF-1R were measured in 21 paired samples of human HCCs and adjacent nontumoral livers using ELISA. The antineoplastic potency of a novel anti–IGF-1R antibody, AVE1642, was examined in five human hepatoma cell lines.Results: Overexpression of IGF-1R was detected in 33% of HCCs and increased activation of IGF-1R was observed in 52% of tumors. AVE1642 alone had moderate inhibitory effects on cell viability. However, its combination with gefitinib, an epidermal growth factor receptor (EGFR) inhibitor, induced supra-additive effects in all cell lines that were associated with cell cycle blockage and inhibition of AKT phosphorylation. The combination of AVE1642 with rapamycin also induced a synergistic reduction of viability and of AKT phosphorylation. Of marked interest, AVE1642 alone up-regulated the phosphorylated and total levels of HER3, the main partner of EGFR, and AVE1642-induced phosphorylation of HER3 was prevented by gefitinib. Moreover, the down-regulation of HER3 expression with siRNA reduced AKT phosphorylation and increased cell sensitivity to AVE1642.Conclusions: These findings indicate that hepatoma cells overcome IGF-1R inhibition through HER3 activation in an EGFR-dependent mechanism, and that HER3 represents a critical mediator in acquired resistance to anti-IGF-1R therapy. These results provide a strong rational for targeting simultaneously EGFR and IGF-1R in clinical trials for HCC]. (Clin Cancer Res 2009;15(17):5445–56)