RESUMO
BACKGROUND: The TMPRSS2/ERG (TE) fusion gene is present in half of the prostate cancers (PCas). The TMPRSS2 and ERG junction of the fusion messenger RNA (mRNA) constitutes a cancer-specific target. Although docetaxel-based chemotherapy is the second line of therapy following development resistance to androgen ablation therapies, it is not curative. Therefore, the development of nontoxic novel monotherapies for targeting TE mRNA in PCa patients and for increasing the clinical efficacy of docetaxel treatment are needed. METHODS: We evaluated multiple approaches to enhance the delivery of TE small interfering RNA (siRNA) containing liposomes including PEGylation, topical treatment with nitroglycerin (NG) to increase permeability and retention, and three different PEG modifications: folate, RGD cyclic peptide, and a bFGF fibroblast growth factor receptor-targeting peptide. The efficacy of the optimized TE siRNA liposome in combination with docetaxel was then evaluated in vivo with or without topical NG in vivo using a VCaP xenograft model. TE fusion protein knockdown in residual tumors was assessed using Western blotting and immunohistochemistry. RESULTS: In vivo therapeutic targeting of TE fusion gene by systemic delivery of RGD-peptide-coated liposomal siRNA nanovectors led to sustained target silencing, suppressed tumor growth in xenograft models and enhanced the efficacy of docetaxel chemotherapy. Simultaneous application of the vasodilator NG to the skin further increased tissue the delivery of siRNA and enhanced target knockdown. CONCLUSION: TE-targeted gene silencing therapy using liposomal nanovectors is a potential therapeutic strategy as a monotherapy and to enhance the efficacy of chemotherapy in patients with advanced PCa.
Assuntos
Docetaxel/farmacologia , Proteínas de Fusão Oncogênica/genética , Neoplasias de Próstata Resistentes à Castração/terapia , RNA Mensageiro/genética , RNA Interferente Pequeno/administração & dosagem , Animais , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Terapia Combinada , Técnicas de Silenciamento de Genes/métodos , Humanos , Lipossomos/administração & dosagem , Masculino , Camundongos , Terapia de Alvo Molecular , Nanopartículas/administração & dosagem , Neoplasias de Próstata Resistentes à Castração/tratamento farmacológico , Neoplasias de Próstata Resistentes à Castração/genética , RNA Interferente Pequeno/genética , Distribuição Aleatória , Regulador Transcricional ERG/deficiência , Regulador Transcricional ERG/genética , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
AIM: In this study, we aimed to therapeutically target eukaryotic elongation factor 2 kinase (eEF-2K) in an in vivo triple-negative breast cancer (TNBC) tumor model. MATERIALS & METHODS: We synthesized a highly monodisperse nanoformulation using polyethylenimine-modified gold nanoparticles (AuNP-PEI) as siRNA delivery vehicle and evaluated gene downregulation. RESULTS: We found that AuNP-PEI/eEF-2K nanoformulation was highly effective for in vitro and in vivo gene downregulation and showed remarkable antitumor efficacy that was associated with eEF-2K knockdown, inhibition of Src and MAPK-ERK signaling pathways in a TNBC orthotopic tumor model. CONCLUSION: Our study suggests that eEF-2K plays an important role in TNBC tumorigenesis and its inhibition by AuNP-PEI/eEF-2K siRNA-based nanotherapeutics may be a potential therapeutic strategy for TNBC.
Assuntos
Ouro/química , Nanopartículas Metálicas/química , RNA Interferente Pequeno/administração & dosagem , Neoplasias de Mama Triplo Negativas/terapia , Animais , Linhagem Celular Tumoral , Regulação para Baixo , Liberação Controlada de Fármacos , Quinase do Fator 2 de Elongação/genética , Quinase do Fator 2 de Elongação/metabolismo , Feminino , Fibroblastos/efeitos dos fármacos , Expressão Gênica , Técnicas de Silenciamento de Genes , Técnicas de Transferência de Genes , Humanos , Nanopartículas Metálicas/toxicidade , Camundongos , Terapia de Alvo Molecular , Nanomedicina , Tamanho da Partícula , Polietilenoimina/química , Transdução de Sinais , Propriedades de SuperfícieRESUMO
Triple negative breast cancer (TNBC) is an aggressive type of breast cancer characterized by the absence of defined molecular targets, including estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2) and is associated with high rates of relapse and distant metastasis despite surgery and adjuvant chemotherapy. The lack of effective targeted therapies for TNBC represents an unmet therapeutic challenge. Eukaryotic elongation factor 2 kinase (eEF2K) is an atypical calcium/calmodulin-dependent serine/threonine kinase that promotes TNBC tumorigenesis, progression, and drug resistance, representing a potential novel molecular target. However, the mechanisms regulating eEF2K expression are unknown. Here, we report that eEF2K protein expression is highly up-regulated in TNBC cells and patient tumors and it is associated with poor patient survival and clinical outcome. We found that loss/reduced expression of miR-603 leads to eEF2K overexpression in TNBC cell lines. Its expression results in inhibition of eEF2K by directly targeting the 3-UTR and the inhibition of tumor cell growth, migration and invasion in TNBC. In vivo therapeutic gene delivery of miR-603 into TNBC xenograft mouse models by systemic administration of miR-603-nanoparticles led to a significant inhibition of eEF2K expression and tumor growth, which was associated with decreased activity of the downstream targets of eEF2K, including Src, Akt, cyclin D1 and c-myc. Our findings suggest that miR-603 functions as a tumor suppressor and loss of miR-603 expression leads to increase in eEF2K expression and contributes to the growth, invasion, and progression of TNBC. Taken together, our data suggest that miR-603-based gene therapy is a potential strategy against TNBC.