RESUMEN
Hepatocellular carcinoma (HCC) is the major type of primary liver cancer and a leading cause of cancer-related deaths worldwide. Cinobufotalin (CBF) is extracted from the skin secretion of the giant toad and clinically used for the treatment of liver cancer, but its molecular mechanism of anti-cancer in HCC has not yet been elucidated. Here, we showed CBF effectively promoted cell apoptosis, induced cell cycle G2-M arrest, inhibited cell proliferation and lipogenesis. Consistently, the lipogenesis ability of xenograft examined by 11C-acetate micro-PET/CT imaging, and the tumor growth rate was notably declined in a centration-dependent manner. The fatty acid profiles showed saturated and mono-unsaturated fatty acid significantly decreased after CBF treatment. Mechanistically, CBF selectively inhibited the expression of SREBP1 and interacted with SREBP1 to prevent it from sterol regulatory elements (SREs), thus inhibiting the expression of lipogenic enzymes. Collectively, our study demonstrates that CBF is a potent native compound that remarkably inhibits HCC lipogenesis and tumorigenesis. CBF may possess this therapeutic potential though interfering with de novo lipid synthesis via SREBP1.
Asunto(s)
Bufanólidos/farmacología , Carcinoma Hepatocelular/tratamiento farmacológico , Lipogénesis/efectos de los fármacos , Neoplasias Hepáticas/tratamiento farmacológico , Proteína 1 de Unión a los Elementos Reguladores de Esteroles/antagonistas & inhibidores , Animales , Apoptosis/efectos de los fármacos , Apoptosis/genética , Bufanólidos/uso terapéutico , Carcinogénesis/efectos de los fármacos , Carcinogénesis/genética , Carcinoma Hepatocelular/patología , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Proliferación Celular/genética , Puntos de Control de la Fase G2 del Ciclo Celular/efectos de los fármacos , Puntos de Control de la Fase G2 del Ciclo Celular/genética , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Humanos , Lipogénesis/genética , Neoplasias Hepáticas/patología , Masculino , Ratones , Simulación del Acoplamiento Molecular , Proteína 1 de Unión a los Elementos Reguladores de Esteroles/metabolismo , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Pyruvate kinase M2 (PKM2) is not only a key rate-limiting enzyme that guides glycolysis, but also acts as a non-metabolic protein in regulating gene transcription. In recent years, a series of studies have confirmed that post-translational modification has become an important mechanism for regulating the function of PKM2, which in turn affects tumorigenesis. In this study, we found that K62 residues were deacetylated, which is related to the prognosis of HCC. Further studies indicate that HDAC8 binds and deacetylates the K62 residue of PKM2. Mechanistically, K62 deacetylation facilitate PKM2 transport into the nucleus and bind ß-catenin, thereby promoting CCND1 gene transcription and cell cycle progression. In addition, the deacetylation of K62 affects the enzyme activity of PKM2 and the flux of glucose metabolism. Therefore, these results suggest that HDAC8 / PKM2 signaling may become a new target for the treatment of HCC.
Asunto(s)
Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patología , Proteínas Portadoras/metabolismo , Núcleo Celular/metabolismo , Glucólisis , Histona Desacetilasas/metabolismo , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patología , Proteínas de la Membrana/metabolismo , Proteínas Represoras/metabolismo , Hormonas Tiroideas/metabolismo , Acetilación , Animales , Carcinoma Hepatocelular/genética , Línea Celular Tumoral , Proliferación Celular , Ciclina D1/genética , Ciclina D1/metabolismo , Fase G1/genética , Regulación Neoplásica de la Expresión Génica , Glucosa/metabolismo , Humanos , Neoplasias Hepáticas/genética , Lisina/metabolismo , Masculino , Ratones , Persona de Mediana Edad , Modelos Biológicos , Unión Proteica , Transporte de Proteínas , Fase S/genética , Regulación hacia Arriba/genética , beta Catenina/metabolismo , Proteínas de Unión a Hormona TiroideRESUMEN
PURPOSE: There is currently no effective noninvasive method for accurate molecular typing of triple negative breast cancer (TNBC) except needle biopsy. Glucoregulated Protein 78 (GRP78) is overexpressed in TNBC cells and tumors which closely related to the invasion, metastasis, and drug resistance of cancer. Meanwhile, it has been verified that VAP peptide bind specifically to GRP78 in vitro and in vivo. In this study, we constructed a GRP78-targeted molecular probe Ga-68-radiolabeled DOTA-VAP conjugate ([68Ga]DOTA-VAP) based on VAP peptide, and evaluated its potential to distinguish TNBC from non-TNBC tumors. PROCEDURES: DOTA-VAP was synthesized and then radiolabeled with Ga-68 to obtain [68Ga]DOTA-VAP. The expression of GRP78 in TNBC MDA-MB-231 and non-TNBC MCF-7 cells was validated by Western Blot, and cell binding or uptake experiments with both [68Ga]DOTA-VAP and 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) were also performed. Biodistribution analysis and positron emission tomography (PET) imaging of [68Ga]DOTA-VAP were carried out in subcutaneous MDA-MB-231 and MCF-7 human breast cancer tumor models with [18F]FDG PET imaging as comparison. RESULTS: [68Ga]DOTA-VAP was prepared with high radiochemical purity which showed excellent stability in vitro. The MDA-MB-231 tumors were clearly visualized by [68Ga]DOTA-VAP PET imaging with a low background, except for the relatively high liver uptake. Cells and tumors of MDA-MB-231 could be distinguished from MCF-7 by [68Ga]DOTA-VAP instead of [18F]FDG. Biodistribution results were consistent with the imaging results. The blocking study with excess cold peptide showed significantly reduced tumor uptake, which indicated the specificity of [68Ga]DOTA-VAP targeting MDA-MB-231 tumors in vivo. CONCLUSIONS: GRP78-targeted PET imaging with [68Ga]DOTA-VAP provided an effective approach for the noninvasive accurate classification of TNBC from other breast cancer subtypes comparing with [18F]FDG. GRP78 may be a potential target for the diagnosis and treatment of TNBC. For clinical transformation, efforts should be made to overcome deficiencies of [68Ga]DOTA-VAP such as relative high uptake in normal tissues.