RESUMO
PURPOSE: Targeted therapies have resulted in major advances in the treatment of HER2-positive breast cancers. Despite this, up to 70% of patients will develop resistance to treatment within 2 years and new strategies for targeting resistant disease are needed. METHODS: To identify potential resistance mechanisms, we used the mouse MMTV-NIC-PTEN+/- spontaneous model of HER2-positive breast cancer and the pan-HER family kinase inhibitor sapatinib. Vehicle and sapatinib-treated tumors were evaluated by immunohistochemistry and proteomic analysis. In vitro studies were carried out to define the role of heme oxygenase 1 (HO-1) and autophagy in resistance to sapatinib and lapatinib, another pan-HER family kinase inhibitor. RESULTS: Treatment of tumor-bearing MMTV-NIC-PTEN+/- mice with sapatinib resulted in delayed tumor progression and increased survival. However, tumors eventually progressed on treatment. Proteomic analysis identified proteins associated with cellular iron homeostasis as being upregulated in the sapatinib-treated tumors. This included HO-1 whose overexpression was confirmed by immunohistochemistry. Overexpression of HO-1 in HER2-expressing SKBR3 breast cancer cells resulted in reduced sensitivity to both pan-HER family kinase inhibitors sapatinib and lapatinib. This was associated with increased autophagy in the HO-1 over-expressing cells. Furthermore, increased autophagy was also seen in the sapatinib-treated tumors. Treatment with autophagy inhibitors was able to increase the sensitivity of the HO-1 over-expressing cells to both lapatinib and sapatinib. CONCLUSION: Together these data indicate a role for HO-1-induced autophagy in resistance to pan-HER family kinase inhibitors.
Assuntos
Autofagia/efeitos dos fármacos , Neoplasias da Mama/tratamento farmacológico , Heme Oxigenase-1/metabolismo , Lapatinib/farmacologia , Proteínas de Membrana/metabolismo , Quinazolinas/farmacologia , Receptor ErbB-2/antagonistas & inibidores , Animais , Antineoplásicos/farmacologia , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Avaliação Pré-Clínica de Medicamentos , Resistencia a Medicamentos Antineoplásicos , Feminino , Humanos , Camundongos , Camundongos Transgênicos , Terapia de Alvo Molecular , Inibidores de Proteínas Quinases/farmacologia , Receptor ErbB-2/metabolismoRESUMO
Pyrazolopyrimidines with potent antiproliferative properties were developed by an adaptive strategy that applies ligand-based design and phenotypic screening iteratively and is informed by biochemical assays. To drive development toward specific oncopathways, compounds were tested against cancer cells that overexpress, or not, AXL kinase. Identified phenotypic hits were found to inhibit oncotargets AXL, RET, and FLT3. Subsequent optimization generated antiproliferative lead compounds with unique selectivity profiles, including selective AXL inhibitors and a highly potent inhibitor of FLT3.
Assuntos
Inibidores de Proteínas Quinases/farmacologia , Receptores Proteína Tirosina Quinases/antagonistas & inibidores , Antineoplásicos , Linhagem Celular Tumoral , Sobrevivência Celular , Desenho de Fármacos , Avaliação Pré-Clínica de Medicamentos , Humanos , Ligantes , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Pirazóis/química , Pirimidinas/química , Tirosina Quinase 3 Semelhante a fms/antagonistas & inibidores , Receptor Tirosina Quinase AxlRESUMO
Metastasis is the major cause of cancer-associated death. Partial activation of the epithelial-to-mesenchymal transition program (partial EMT) was considered a major driver of tumour progression from initiation to metastasis. However, the role of EMT in promoting metastasis has recently been challenged, in particular concerning effects of the Snail and Twist EMT transcription factors (EMT-TFs) in pancreatic cancer. In contrast, we show here that in the same pancreatic cancer model, driven by Pdx1-cre-mediated activation of mutant Kras and p53 (KPC model), the EMT-TF Zeb1 is a key factor for the formation of precursor lesions, invasion and notably metastasis. Depletion of Zeb1 suppresses stemness, colonization capacity and in particular phenotypic/metabolic plasticity of tumour cells, probably causing the observed in vivo effects. Accordingly, we conclude that different EMT-TFs have complementary subfunctions in driving pancreatic tumour metastasis. Therapeutic strategies should consider these potential specificities of EMT-TFs to target these factors simultaneously.
Assuntos
Movimento Celular , Plasticidade Celular , Transição Epitelial-Mesenquimal , Neoplasias Pulmonares/metabolismo , Neoplasias Experimentais/metabolismo , Neoplasias Pancreáticas/metabolismo , Homeobox 1 de Ligação a E-box em Dedo de Zinco/metabolismo , Animais , Proliferação de Células , Genes p53 , Predisposição Genética para Doença , Proteínas de Homeodomínio/genética , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/secundário , Camundongos Transgênicos , Mutação , Neoplasias Experimentais/genética , Neoplasias Experimentais/patologia , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patologia , Fenótipo , Proteínas Proto-Oncogênicas p21(ras)/genética , Interferência de RNA , Transdução de Sinais , Fatores de Transcrição da Família Snail/genética , Fatores de Transcrição da Família Snail/metabolismo , Fatores de Tempo , Transativadores/genética , Transfecção , Carga Tumoral , Células Tumorais Cultivadas , Proteína 1 Relacionada a Twist/genética , Proteína 1 Relacionada a Twist/metabolismo , Homeobox 1 de Ligação a E-box em Dedo de Zinco/genéticaRESUMO
Activation of signalling by fibroblast growth factor receptor leads to phosphorylation of the signalling attenuator human Sprouty 2 (hSpry2) on residue Y55. This event requires the presence of the signalling adaptor fibroblast growth factor receptor substrate 2 (FRS2). The phosphorylation of hSpry2 is therefore mediated by an intermediate kinase. Using a SRC family kinase-specific inhibitor and mutant cells, we show that hSpry2 is a direct substrate for SRC family kinases, including SRC itself. Activation of SRC via fibroblast growth factor signalling is dependent upon FRS2 and fibroblast growth factor receptor kinase activity. SRC forms a complex with hSpry2 and this interaction is enhanced by hSpry2 phosphorylation. Phosphorylation of hSpry2 is required for hSpry2 to inhibit activation of the extracellular signal-regulated kinase pathway. These results show that recruitment of SRC to FRS2 leads to activation of signal attenuation pathways.