Epithelial-to-Mesenchymal Transition Is a Mechanism of ALK Inhibitor Resistance in Lung Cancer Independent of ALK Mutation Status

Abstract

Mutations in the ALK gene are detectable in approximately 40% of ALK-rearranged lung cancers resistant to ALK inhibitors. Although epithelial-to-mesenchymal transition (EMT) is a mechanism of resistance to various targeted drugs, its involvement in ALK inhibitor resistance is largely unknown. In this study, we report that both ALK-mutant L1196M and EMT were concomitantly detected in a single crizotinibresistant lesion in a patient with ALK-rearranged lung cancer. Digital PCR analyses combined with microdissection after IHC staining for EMT markers revealed that ALK L1196M was predominantly detected in epithelial-type tumor cells, indicating that mesenchymal phenotype and ALK mutation can coexist as independent mechanisms underlying ALK inhibitor-resistant cancers. Preclinical experiments with crizotinib-resistant lung cancer cells showed that EMT associated with decreased expression of miR-200c and increased expression of ZEB1 caused cross-resistance to new-generation ALK inhibitors alectinib, ceritinib, and lorlatinib. Pretreatment with the histone deacetylase (HDAC) inhibitor quisinostat overcame this resistance by reverting EMT in vitro and in vivo. These findings indicate that HDAC inhibitor pretreatment followed by a new ALK inhibitor may be useful to circumvent resistance constituted by coexistence of resistance mutations and EMT in the heterogeneous tumor. Significance: These findings show that dual inhibition of HDAC and ALK receptor tyrosine kinase activities provides a means to circumvent crizotinib resistance in lung cancer.

Patient‐derived xenograft models of non‐small cell lung cancer for evaluating targeted drug sensitivity and resistance

“…34 We have reported that EMT is a mechanism of ALK-TKI resistance independent of ALK resistance mutation status. 22 In the present study, E-cadherin expression was decreased in both #7 P6 OR1 and #7 P6 OR2, compared with #7. Interestingly, ZEB1 expression was increased in #7 P6 OR1, but not #7 P6 OR2, whereas vimentin expression was increased in both #7 P6 OR1 and #7 P6…”

“…We recently reported that inhibition of histone deacetylase (HDAC) is a therapeutic candidate to overcome EMT-mediated ALK inhibitor resistance. 22 We therefore further examined the effect of HDAC inhibition on sensitivity to EGFR inhibitors using organoid culture #7 P6 OR1. Very interestingly, either osimertinib or HDAC inhibitor quisinostat inhibited viability of the organoids by 50%, and pretreatment of quisinostat followed by osimertinib further suppressed the viability ( Figure S4).…”

miR-93-5p enhances migration and invasion by targeting RGMB in squamous cell carcinoma of the head and neck

“…During tumorigenesis, cells lose their initial characteristics and are transformed into mesenchymal fibroblast-like cells. This morphological transition of EMT fosters the ability of cells to break away from their originating tissue and allows them to migrate and invade into the surrounding environment [28,29]. Additionally, tumor epithelial cells that undergo EMT share many characteristics with stem cells, and this significantly complicates systemic therapies used to treat related metastatic diseases [29,30].…”

Functional diagnostics using fresh uncultured lung tumor cells to guide personalized treatments

“…Contrasting with the above target-matched responses, EpCAM+ cells derived from three ALK fusion+ tumors showed low sensitivity to the ALK inhibitors ceritinib and crizotinib ( Fig 4E-F). Since epithelial-to-mesenchymal transition (EMT) can explain resistance to ALK inhibitors, 26,27 primary tumor tissues were stained with epithelial E-cadherin and mesenchymal vimentin markers (Table S2; six of 18 patient samples showed vimentin staining positive tumor cells). This confirmed EMT in all three ALK+ samples tested in the FUTC assay ( Fig 4G and S2E), possibly explaining why these samples demonstrated poor response to ALK inhibition.…”