Epithelial-to-Mesenchymal Transition and Integrin-Linked Kinase Mediate Sensitivity to Epidermal Growth Factor Receptor Inhibition in Human Hepatoma Cells

Abstract

Hepatocellular carcinoma (HCC) is associated with a poor prognosis due to late diagnoses and a lack of effective treatment options. Epidermal growth factor receptor (EGFR)-targeted therapies have been effective in other cancers. However, erlotinib and cetuximab have shown only modest efficacy in clinical trials of HCC. We examined epithelial-to-mesenchymal transition (EMT) as a determinant of sensitivity of HCC to EGFR inhibitors. A panel of 12 human hepatoma cell lines were classified as epithelial or mesenchymal based on their expression of E-cadherin and vimentin. The resulting classification correlated with a previous microarray analysis of human hepatoma cell lines whereby the mesenchymal cell lines were shown to have increased expression of genes involved in metastasis and invasion. Sensitivity to erlotinib, gefitinib, and cetuximab was assessed and the epithelial cell lines were found to be significantly more susceptible to all three agents. Analysis of the EGFR pathway showed that EMT status was independent of EGFR expression or downstream extracellular signal-regulated kinase activation and only the epithelial cell lines expressed ErbB3. Interestingly, mesenchymal cells resistant to EGFR inhibitors had increased AKT and signal transducer and activator of transcription-3 activation through elevated expression of integrin-linked kinase (ILK). Mesenchymal cell lines were therefore experimentally transformed with kinaseinactive ILK (KI-ILK) with a resulting decrease in ILK activity and activation of AKT. KI-ILK transformants showed increased sensitivity to EGFR inhibitors both in vitro and in an in vivo xenograft model. These data suggest that EMT predicts HCC sensitivity to EGFR-targeted therapies and that ILK is a novel target to overcome HCC resistance to EGFR inhibition.

Epithelial-to-Mesenchymal Transition Rewires the Molecular Path to PI3K-Dependent Proliferation

“…For example, a correlation between EMT status and EGF receptor (EGFR) dependency has been shown in cell lines and patients, where a more epithelial phenotype is associated with heightened sensitivity to EGFR inhibition (12)(13)(14). A similar relationship between EMT status and addiction to oncogenic KRAS and mitogen-activated protein kinase (MAPK) signaling has also been reported ( 15,16 ).…”

Molecular mechanisms of resistance to the EGFR monoclonal antibody cetuximab

“…Overall, EMT and ILK may play a role in resistance to cetuximab. 196 In 2010, mesenchymal-like squamous cell carcinomas were shown to be resistant to cetuximab treatment. 193 Using immunohistochemistry, flow cytometry and gene expression profiling, researchers identified SCC cell lines that were epithelial-like and mesenchymal-like based on E-cadherin and vimentin expression levels.…”

Integrin-linked kinase mediates CTGF-induced epithelial to mesenchymal transition in alveolar type II epithelial cells

“…CTGF has the ability to bind to cell surface integrins, thus activating ILK signaling. ILK has been identified as a regulator of EMT in several epithelia e.g., renal, ovary, and lens and mammary glands (25)(26)(27). We showed that AT II cells with overexpression These data indicate that overexpression of CTGF-induced EMT in AT II cells is at least in part mediated by ILK.…”

“…The principal CTGF receptor is the heterodimeric cell surface integrin complexes (19)(20)(21), while integrin-linked kinase (ILK) is a key mediator of integrin signaling that interacts with the cytoplasmic domain of β integrins (22)(23)(24). Most Articles importantly, ILK signaling plays a critical role in EMT under many pathological conditions (25)(26)(27).…”