RESUMO
Gain of function (GOF) DNA binding domain (DBD) mutations of TP53 upregulate chromatin regulatory genes that promote genome-wide histone methylation and acetylation. Here, we therapeutically exploit the oncogenic GOF mechanisms of p53 codon 158 (Arg158) mutation, a DBD mutant found to be prevalent in lung carcinomas. Using high throughput compound screening and combination analyses, we uncover that acetylating mutp53R158G could render cancers susceptible to cisplatin-induced DNA stress. Acetylation of mutp53R158G alters DNA binding motifs and upregulates TRAIP, a RING domain-containing E3 ubiquitin ligase which dephosphorylates IĸB and impedes nuclear translocation of RelA (p65), thus repressing oncogenic nuclear factor kappa-B (NF-ĸB) signaling and inducing apoptosis. Given that this mechanism of cytotoxic vulnerability appears inapt in p53 wild-type (WT) or other hotspot GOF mutp53 cells, our work provides a therapeutic opportunity specific to Arg158-mutp53 tumors utilizing a regimen consisting of DNA-damaging agents and mutp53 acetylators, which is currently being pursued clinically.
Assuntos
Códon/genética , Mutação/genética , Neoplasias/genética , Proteína Supressora de Tumor p53/genética , Acetilação/efeitos dos fármacos , Animais , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Apoptose/efeitos dos fármacos , Apoptose/genética , Caspase 3/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Cisplatino/farmacologia , Epigênese Genética/efeitos dos fármacos , Mutação com Ganho de Função/genética , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Ácidos Hidroxâmicos/farmacologia , Camundongos SCID , Modelos Biológicos , Proteínas Mutantes/metabolismo , NF-kappa B/metabolismo , Neoplasias/tratamento farmacológico , Motivos de Nucleotídeos/genética , Poli(ADP-Ribose) Polimerases/metabolismo , Ligação Proteica/efeitos dos fármacos , Isoformas de Proteínas/genética , Sulfonamidas/farmacologia , Topotecan/farmacologia , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
c-MET receptors are activated in cancers through genomic events like tyrosine kinase domain mutations, juxtamembrane splicing mutation and amplified copy numbers, which can be inhibited by c-MET small molecule inhibitors. Here, we discover that the most common polymorphism known to affect MET gene (N375S), involving the semaphorin domain, confers exquisite binding affinity for HER2 and enables METN375S to interact with HER2 in a ligand-independent fashion. The resultant METN375S/HER2 dimer transduces potent proliferative, pro-invasive and pro-metastatic cues through the HER2 signaling axis to drive aggressive squamous cell carcinomas of the head and neck (HNSCC) and lung (LUSC), and is associated with poor prognosis. Accordingly, HER2 blockers, but not c-MET inhibitors, are paradoxically effective at restraining in vivo and in vitro models expressing METN375S. These results establish METN375S as a biologically distinct and clinically actionable molecular subset of SCCs that are uniquely amenable to HER2 blocking therapies.
Assuntos
Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/patologia , Proteínas Proto-Oncogênicas c-met/genética , Proteínas Proto-Oncogênicas c-met/metabolismo , Receptor ErbB-2/metabolismo , Animais , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Carcinoma de Células Escamosas/tratamento farmacológico , Carcinoma de Células Escamosas/mortalidade , Linhagem Celular Tumoral , Neoplasias de Cabeça e Pescoço/tratamento farmacológico , Neoplasias de Cabeça e Pescoço/genética , Neoplasias de Cabeça e Pescoço/mortalidade , Neoplasias de Cabeça e Pescoço/patologia , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/mortalidade , Neoplasias Pulmonares/patologia , Camundongos , Mutação , Fenótipo , Fosforilação/efeitos dos fármacos , Polimorfismo Genético , Prognóstico , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Proto-Oncogênicas c-met/química , Receptor ErbB-2/antagonistas & inibidores , Transdução de Sinais/efeitos dos fármacos , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Sorafenib, a multikinase inhibitor, is currently used as monotherapy for advanced renal cell carcinoma (RCC). However, adverse effects associated with its use have been experienced by some patients. In this study, we examined the antitumor and antiangiogenic activities of low-dose sorafenib in combination with the MEK inhibitor AZD6244 (sorafenib/AZD6244) in a preclinical model of RCC. Primary RCC 08-0910 and RCC 786-0 cells as well as patient-derived RCC models were used to study the antitumor and antiangiogenic activities of sorafenib/AZD6244. Changes of biomarkers relevant to angiogenesis and cell cycle were determined by western immunoblotting. Microvessel density, apoptosis and cell proliferation were analyzed by immunohistochemistry. Treatment of RCC 786-0 cells with sorafenib/AZD6244 resulted in G1 cell cycle arrest and blockade of serum-induced cell migration. Sorafenib/AZD6244 induced apoptosis in primary RCC 08-0910 cells at low concentrations. In vivo addition of AZD6244 to sorafenib significantly augmented the antitumor activity of sorafenib and allowed dose reduction of sorafenib without compromising its antitumor activity. Sorafenib/AZD6244 potently inhibited angiogenesis and phosphorylation of VEGFR-2, PDGFR-ß and ERK, p90RSK, p70S6K, cdk-2 and retinoblastoma. Sorafenib/AZD6244 also caused upregulation of p27, Bad and Bim but downregulation of survivin and cyclin B1. These resulted in a reduction in cellular proliferation and the induction of tumor cell apoptosis. Our findings showed that AZD6244 and sorafenib complement each other to inhibit tumor growth. This study provides sound evidence for the clinical investigation of low-dose sorafenib in combination with AZD6244 in patients with advanced RCC.
