RESUMO
Expression of the Notch ligand Jagged 1 (JAG1) and Notch activation promote poor-prognosis in breast cancer. We used high throughput screens to identify elements responsible for Notch activation in this context. Chemical kinase inhibitor and kinase-specific small interfering RNA libraries were screened in a breast cancer cell line engineered to report Notch. Pathway analyses revealed MAPK-ERK signaling to be the predominant JAG1/Notch regulator and this was supported by gene set enrichment analyses in 51 breast cancer cell lines. In accordance with the chemical screen, kinome small interfering RNA high throughput screens identified Tribbles homolog 3 (TRB3), a known regulator of MAPK-ERK, among the most significant hits. We demonstrate that TRB3 is a master regulator of Notch through the MAPK-ERK and TGFß pathways. Complementary in vitro and in vivo studies underscore the importance of TRB3 for tumor growth. These data demonstrate a dominant role for TRB3 and MAPK-ERK/TGFß pathways as Notch regulators in breast cancer, establishing TRB3 as a potential therapeutic target.
Assuntos
Proteínas de Ciclo Celular/metabolismo , Sistema de Sinalização das MAP Quinases , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Receptor Notch1/metabolismo , Proteínas Repressoras/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Animais , Western Blotting , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Proteínas de Ligação ao Cálcio/genética , Proteínas de Ligação ao Cálcio/metabolismo , Proteínas de Ciclo Celular/genética , Linhagem Celular , Linhagem Celular Tumoral , Feminino , Células Hep G2 , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/genética , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Subunidade gama Comum de Receptores de Interleucina/deficiência , Subunidade gama Comum de Receptores de Interleucina/genética , Proteína Jagged-1 , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos NOD , Camundongos Knockout , Camundongos SCID , Inibidores de Proteínas Quinases/isolamento & purificação , Inibidores de Proteínas Quinases/farmacologia , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Interferência de RNA , Receptor Notch1/genética , Proteínas Repressoras/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Proteínas Serrate-Jagged , Transdução de Sinais/efeitos dos fármacos , Fator de Crescimento Transformador beta/genética , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The Notch ligand, JAG1 is associated with breast cancer recurrence. Herein, we report on a genomics approach to elucidate mechanisms downstream of JAG1 that promote breast cancer growth. In a survey of 46 breast cancer cell lines, we found that triple negative (TN; basal and mesenchymal ER-, PR-, and Her2-negative) lines express JAG1 at significantly higher levels than do HER2(+) or luminal (ER(+)) Her2(-) cell lines. In contrast to the luminal lines tested (T47D and MCF7), TN breast cancer cell lines (HCC1143 and MDA MB231) display high-level JAG1 expression and growth inhibition with RNA interference-induced JAG1 down-regulation. We used microarray profiling of TN tumor cells transfected with JAG1 siRNA to identify JAG1-regulated genes (P
Assuntos
Neoplasias da Mama/metabolismo , Proteínas de Ligação ao Cálcio/metabolismo , Ciclina D1/metabolismo , Regulação Neoplásica da Expressão Gênica , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Proteínas de Membrana/metabolismo , Receptores Notch/metabolismo , Transdução de Sinais/genética , Western Blotting , Neoplasias da Mama/genética , Proteínas de Ligação ao Cálcio/genética , Linhagem Celular Tumoral , Imunoprecipitação da Cromatina , Ciclina D1/genética , Feminino , Expressão Gênica , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/genética , Proteína Jagged-1 , Proteínas de Membrana/genética , Análise de Sequência com Séries de Oligonucleotídeos , Regiões Promotoras Genéticas/genética , RNA Interferente Pequeno , Receptor ErbB-2/biossíntese , Receptor ErbB-2/genética , Receptores de Estrogênio/biossíntese , Receptores de Estrogênio/genética , Receptores Notch/genética , Receptores de Progesterona/biossíntese , Receptores de Progesterona/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Proteínas Serrate-Jagged , TransfecçãoRESUMO
The recognition of breast cancer as a molecularly heterogeneous disease where individual tumors display cellular hierarchy containing "primitive" stem-like tumor-initiating cells (TICs) and their derivatives, has directed efforts towards the development of personalized targeted therapies based on the characteristics of individual cancers. Targeted therapies are designed to attack processes that uniquely support cancer progression, including maintenance of TICs, invasion, metastasis, cell survival and tumor-related angiogenesis and thereby result in less collateral damage than conventional chemotherapy. Recently, it has been demonstrated that pathways such as Hedgehog (Hh), Wnt and Notch, which regulate development during embryonic life and somatic stem cells (SCs) in the adult organism, can be reactivated in malignancies and support the TIC compartment. Herein, we review the role of developmental pathways in stem cell biology and provide an up-to-date survey of pre-clinical and clinical trials of novel strategies to target them.