Lorlatinib Treatment Elicits Multiple On- and Off-Target Mechanisms of Resistance in ALK-Driven Cancer

Abstract

Targeted therapy changed the standard of care in ALK-dependent tumors. However, resistance remains a major challenge. Lorlatinib is a third-generation ALK inhibitor that inhibits most ALK mutants resistant to current ALK inhibitors. In this study, we utilize lorlatinib-resistant anaplastic large cell lymphoma (ALCL), non-small cell lung cancer (NSCLC), and neuroblastoma cell lines in vitro and in vivo to investigate the acquisition of resistance and its underlying mechanisms. ALCL cells acquired compound ALK mutations G1202R/G1269A and C1156F/L1198F in vitro at high drug concentrations. ALCL xenografts selected in vivo showed recurrent N1178H (5/10 mice) and G1269A (4/10 mice) mutations. Interestingly, intracellular localization of NPM/ALKN 1178H skewed toward the cytoplasm in human cells, possibly mimicking overexpression. RNA sequencing of resistant cells showed significant alteration of PI3K/AKT and RAS/MAPK pathways. Functional validation by small-molecule inhibitors confirmed the involvement of these pathways in resistance to lorlatinib. NSCLC cells exposed in vitro to lorlatinib acquired hyperactivation of EGFR, which was blocked by erlotinib to restore sensitivity to lorlatinib. In neuroblastoma, whole-exome sequencing and proteomic profiling of lorlatinib-resistant cells revealed a truncating NF1 mutation and hyperactivation of EGFR and ErbB4. These data provide an extensive characterization of resistance mechanisms that may arise in different ALK-positive cancers following lorlatinib treatment. Significance: High-throughput genomic, transcriptomic, and proteomic profiling reveals various mechanisms by which multiple tumor types acquire resistance to the third-generation ALK inhibitor lorlatinib. Cancer Res; 78(24); 6866-80. Ó2018 AACR.

Emerging therapies for non-small cell lung cancer

“…Most ALK-positive patients treated with first-or second-generation ALK-TKI would develop resistance to TKI including ALK Gly1202Arg (G1202R) solvent-front mutation located at the solvent-front region of ALK, and can impair drug binding through steric hindrance [106,129]. A preclinical data showed lorlatinib was the only ALK inhibitor to potently inhibit wide-range ALK secondary mutations, including ALK G1202R [130]. So far for lorlatinib, only phase 1 and 2 study has been released, and the results were promising [131].…”

Protein arginine methyltransferase 5 promotes metastasis via enhancing EGFR transcription and modulating AKT1 activation by methylation

“…4b). EGFR was overexpressed in neuroblastoma patients and associated with resistance to ALK inhibitors and chemotherapy [44][45][46] . However, the role of EGFR in neuroblastoma has not been as thoroughly investigated in neuroblastoma as it has in other cancers such as breast cancer, lung cancer, and colorectal cancer 47 .…”

Response to Crizotinib Re-administration After Progression on Lorlatinib in a Patient With ALK-rearranged Non–small-cell Lung Cancer

“…7,8 Although lorlatinib response was observed, relapse on lorlatinib ultimately developed. [9][10][11] Mechanisms of lorlatinib resistance were reported, [9][10][11] but remained unknown. Moreover, post-lorlatinib treatment has not been determined.…”