RESUMO
Lung cancer is one of the most aggressive tumour types. Targeted therapies stratified by oncogenic drivers have substantially improved therapeutic outcomes in patients with non-small-cell lung cancer (NSCLC)1. However, such oncogenic drivers are not found in 25-40% of cases of lung adenocarcinoma, the most common histological subtype of NSCLC2. Here we identify a novel fusion transcript of CLIP1 and LTK using whole-transcriptome sequencing in a multi-institutional genome screening platform (LC-SCRUM-Asia, UMIN000036871). The CLIP1-LTK fusion was present in 0.4% of NSCLCs and was mutually exclusive with other known oncogenic drivers. We show that kinase activity of the CLIP1-LTK fusion protein is constitutively activated and has transformation potential. Treatment of Ba/F3 cells expressing CLIP1-LTK with lorlatinib, an ALK inhibitor, inhibited CLIP1-LTK kinase activity, suppressed proliferation and induced apoptosis. One patient with NSCLC harbouring the CLIP1-LTK fusion showed a good clinical response to lorlatinib treatment. To our knowledge, this is the first description of LTK alterations with oncogenic activity in cancers. These results identify the CLIP1-LTK fusion as a target in NSCLC that could be treated with lorlatinib.
Assuntos
Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/patologia , Transformação Celular Neoplásica/genética , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Proteínas Associadas aos Microtúbulos/genética , Proteínas de Neoplasias/genética , Proteínas de Fusão Oncogênica/genética , Receptores Proteína Tirosina Quinases/genética , Adenocarcinoma de Pulmão/tratamento farmacológico , Adenocarcinoma de Pulmão/genética , Adenocarcinoma de Pulmão/patologia , Aminopiridinas/farmacologia , Aminopiridinas/uso terapêutico , Animais , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Linhagem Celular Tumoral , Transformação Celular Neoplásica/efeitos dos fármacos , Cromossomos Humanos Par 12/genética , Cromossomos Humanos Par 15/genética , Humanos , Lactamas/farmacologia , Lactamas/uso terapêutico , Neoplasias Pulmonares/tratamento farmacológico , Camundongos , Camundongos Nus , Pirazóis/farmacologia , Pirazóis/uso terapêutico , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Introduction: EGFR exon 20 insertion mutations account for 5% to 10% of EGFR-mutated NSCLC. CLN-081 (formerly known as TAS6417), a novel covalent EGFR tyrosine kinase inhibitor, exhibits pan-mutation selective efficacy, including exon 20 insertions, in the clinical setting. Nevertheless, some patients may not respond to CLN-081 and resistance to CLN-081 may emerge over time in others. Methods: We exposed Ba/F3 cells transduced with EGFR exon 20 insertions (Y764_V765 insHH or A767_S768insSVD) to increasing concentrations of CLN-081 to generate resistant cells and then subjected their complementary DNA to sequencing to identify acquired mutations. We then evaluated effects of small molecules on engineered Ba/F3 cells on the basis of proliferation assays, Western blotting, and xenograft models. Results: All CLN-081 resistant clones harbored the EGFR C797S mutation. Ba/F3 cells with C797S (Ba/F3-C797S) were resistant to EGFR tyrosine kinase inhibitors targeting EGFR exon 20 insertion mutations, including CLN-081. Pimitespib, a selective heat shock protein 90 inhibitor, induced apoptosis in Ba/F3-C797S cells in vitro and inhibited growth of Ba/F3-C797S tumors in vivo. Ba/F3 cells with A763_Y764insFQEA-C797S remained sensitive to erlotinib. Conclusions: We conclude that the EGFR C797S mutation confers resistance to CLN-081. Our preclinical data suggest a potential small molecule to overcome CLN-081 resistance, which may benefit patients with lung cancer with EGFR exon 20 insertions.