RESUMO
The combination of BRAF and MEK inhibitors demonstrated significant clinical benefit in patients with BRAF-mutant non-small cell lung cancer (NSCLC). However, the molecular mechanisms of acquired resistance to BRAF and MEK inhibition in NSCLC are still unknown. Herein, we report a case of a 76-year-old man with a history of smoking who was diagnosed with BRAF V600E-mutant lung adenocarcinoma (PD-L1â >â 50%) and subsequently candidate to first-line therapy with pembrolizumab. After 18â months since the start of immunotherapy, computed tomography scan showed disease progression and a second-line therapy with dabrafenib and trametinib was initiated. Seven months later, due to a suspect disease progression, a left supraclavicular lymphadenectomy was performed and next-generation sequencing analysis revealed the appearance of MET exon 14 skipping mutation, while fluorescence in situ hybridization analysis showed MET amplification. The patient is still on BRAF and MEK inhibitor treatment. Our case highlights the relevance of performing tumor tissue rebiopsy at the time of progression during treatment with BRAF/MEK inhibition with the aim of identifying putative mechanisms of resistance.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica , Carcinoma Pulmonar de Células não Pequenas , Resistencia a Medicamentos Antineoplásicos , Imidazóis , Neoplasias Pulmonares , Mutação , Oximas , Proteínas Proto-Oncogênicas B-raf , Proteínas Proto-Oncogênicas c-met , Piridonas , Pirimidinonas , Humanos , Piridonas/administração & dosagem , Pirimidinonas/administração & dosagem , Masculino , Oximas/administração & dosagem , Idoso , Proteínas Proto-Oncogênicas B-raf/genética , Imidazóis/administração & dosagem , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/patologia , Proteínas Proto-Oncogênicas c-met/genética , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêuticoRESUMO
The overexpression of the ecotropic viral integration site-1 gene (EVI1/MECOM) marks the most lethal acute myeloid leukemia (AML) subgroup carrying chromosome 3q26 abnormalities. By taking advantage of the intersectionality of high-throughput cell-based and gene expression screens selective and pan-histone deacetylase inhibitors (HDACis) emerge as potent repressors of EVI1. To understand the mechanism driving on-target anti-leukemia activity of this compound class, here we dissect the expression dynamics of the bone marrow leukemia cells of patients treated with HDACi and reconstitute the EVI1 chromatin-associated co-transcriptional complex merging on the role of proliferation-associated 2G4 (PA2G4) protein. PA2G4 overexpression rescues AML cells from the inhibitory effects of HDACis, while genetic and small molecule inhibition of PA2G4 abrogates EVI1 in 3q26 AML cells, including in patient-derived leukemia xenografts. This study positions PA2G4 at the crosstalk of the EVI1 leukemogenic signal for developing new therapeutics and urges the use of HDACis-based combination therapies in patients with 3q26 AML.