RESUMO
PURPOSE: Dosimetry for melanoma-targeted radionuclide therapy (TRT) with [131 I]ICF01012, a melanin ligand, has been previously evaluated in mice bearing melanomas. In this study, activity distribution and dosimetry are performed on healthy rabbits (Fauve de Bourgogne) using SPECT-CT imaging and ex vivo measurements. MATERIAL AND METHODS: Ex vivo biodistribution (i.v. injection: 370 kBq/kg, n = 2 per point) is performed on blood, eyes, brain, lung, liver, kidneys, heart, stomach, and spleen. Dosimetry calculations follow the MIRD formalism: S values are calculated from CT images using the GATE Monte Carlo platform and activity distributions are obtained from SPECT-CT imaging (i.v. injection: 37 MBq/kg n = 3 per point). A specific study is presented to assess dose to human retina. RESULTS: Time-integrated activities based on SPECT-CT are in accordance with ex vivo measurements except for spleen. Doses to liver and eyes are the most significant, with respectively, 6.38 ± 0.50 Gy/GBq (evaluated through SPECT-CT imaging) and 45.8 ± 7.9 Gy/GBq (evaluated through ex vivo measurements). Characterization of ocular [131 I]ICF01012 biodistribution in rabbits and quantification of melanin allowed to assess a dose of 3.07 ± 0.70 Gy/GBq to human retina. CONCLUSION: This study sustains [131 I]ICF01012 as a good candidate for melanoma TRT and open perspectives for personalized dosimetry calculation during phase I clinical transfer.
Assuntos
Radioisótopos do Iodo/uso terapêutico , Melanoma/radioterapia , Quinoxalinas/uso terapêutico , Animais , Feminino , Humanos , Masculino , Melanoma/diagnóstico por imagem , Melanoma/metabolismo , Quinoxalinas/farmacocinética , Coelhos , Radiometria , Dosagem Radioterapêutica , Tomografia Computadorizada com Tomografia Computadorizada de Emissão de Fóton Único , Software , Distribuição Tecidual , Proteína Tumoral 1 Controlada por TraduçãoRESUMO
In breast cancer, a key feature of peritumoral adipocytes is their loss of lipid content observed both in vitro and in human tumors. The free fatty acids (FFAs), released by adipocytes after lipolysis induced by tumor secretions, are transferred and stored in tumor cells as triglycerides in lipid droplets. In tumor cell lines, we demonstrate that FFAs can be released over time from lipid droplets through an adipose triglyceride lipase-dependent (ATGL-dependent) lipolytic pathway. In vivo, ATGL is expressed in human tumors where its expression correlates with tumor aggressiveness and is upregulated by contact with adipocytes. The released FFAs are then used for fatty acid ß-oxidation (FAO), an active process in cancer but not normal breast epithelial cells, and regulated by coculture with adipocytes. However, in cocultivated cells, FAO is uncoupled from ATP production, leading to AMPK/acetyl-CoA carboxylase activation, a circle that maintains this state of metabolic remodeling. The increased invasive capacities of tumor cells induced by coculture are completely abrogated by inhibition of the coupled ATGL-dependent lipolysis/FAO pathways. These results show a complex metabolic symbiosis between tumor-surrounding adipocytes and cancer cells that stimulate their invasiveness, highlighting ATGL as a potential therapeutic target to impede breast cancer progression.
Assuntos
Adipócitos/metabolismo , Neoplasias da Mama/metabolismo , Carcinoma Ductal de Mama/metabolismo , Carcinoma Lobular/metabolismo , Ácidos Graxos não Esterificados/metabolismo , Lipase/metabolismo , Lipólise , Acetil-CoA Carboxilase/metabolismo , Trifosfato de Adenosina/metabolismo , Adenilato Quinase/metabolismo , Idoso , Animais , Neoplasias da Mama/patologia , Carcinoma Ductal de Mama/patologia , Carcinoma Lobular/patologia , Linhagem Celular Tumoral , Proliferação de Células , Técnicas de Cocultura , Feminino , Humanos , Camundongos , Pessoa de Meia-Idade , Invasividade Neoplásica , Oxirredução , Triglicerídeos/metabolismoRESUMO
Cell migration is a critical step in the progression of prostate cancer to the metastatic state, the lethal form of the disease. The antidiabetic drug metformin has been shown to display antitumoral properties in prostate cancer cell and animal models; however, its role in the formation of metastases remains poorly documented. Here, we show that metformin reduces the formation of metastases to fewer solid organs in an orthotopic metastatic prostate cancer cell model established in nude mice. As predicted, metformin hampers cell motility in PC3 and DU145 prostate cancer cells and triggers a radical reorganization of the cell cytoskeleton. The small GTPase Rac1 is a master regulator of cytoskeleton organization and cell migration. We report that metformin leads to a major inhibition of Rac1 GTPase activity by interfering with some of its multiple upstream signaling pathways, namely P-Rex1 (a Guanine nucleotide exchange factor and activator of Rac1), cAMP, and CXCL12/CXCR4, resulting in decreased migration of prostate cancer cells. Importantly, overexpression of a constitutively active form of Rac1, or P-Rex, as well as the inhibition of the adenylate cyclase, was able to reverse the antimigratory effects of metformin. These results establish a novel mechanism of action for metformin and highlight its potential antimetastatic properties in prostate cancer.
Assuntos
Movimento Celular/efeitos dos fármacos , Metformina/farmacologia , Neoplasias da Próstata/enzimologia , Neoplasias da Próstata/patologia , Proteínas rac1 de Ligação ao GTP/antagonistas & inibidores , Citoesqueleto de Actina/efeitos dos fármacos , Citoesqueleto de Actina/metabolismo , Animais , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Quimiocina CXCL12/farmacologia , Quimiotaxia/efeitos dos fármacos , AMP Cíclico/metabolismo , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Humanos , Masculino , Camundongos Nus , Invasividade Neoplásica , Metástase Neoplásica , Ensaios Antitumorais Modelo de Xenoenxerto , Proteínas rac1 de Ligação ao GTP/metabolismoRESUMO
Achondroplasia is a rare genetic disease characterized by abnormal bone development, resulting in short stature. It is caused by a single point mutation in the gene coding for fibroblast growth factor receptor 3 (FGFR3), which leads to prolonged activation upon ligand binding. To prevent excessive intracellular signaling and rescue the symptoms of achondroplasia, we have developed a recombinant protein therapeutic approach using a soluble form of human FGFR3 (sFGFR3), which acts as a decoy receptor and prevents FGF from binding to mutant FGFR3. sFGFR3 was injected subcutaneously to newborn Fgfr3(ach/+) mice-the mouse model of achondroplasia-twice per week throughout the growth period during 3 weeks. Effective maturation of growth plate chondrocytes was restored in bones of treated mice, with a dose-dependent enhancement of skeletal growth in Fgfr3(ach/+) mice. This resulted in normal stature and a significant decrease in mortality and associated complications, without any evidence of toxicity. These results describe a new approach for restoring bone growth and suggest that sFGFR3 could be a potential therapy for children with achondroplasia and related disorders.
Assuntos
Acondroplasia/tratamento farmacológico , Desenvolvimento Ósseo/efeitos dos fármacos , Receptor Tipo 3 de Fator de Crescimento de Fibroblastos/uso terapêutico , Animais , Feminino , Humanos , Masculino , Camundongos , Transdução de Sinais/efeitos dos fármacosRESUMO
Cancer-associated fibroblasts (CAF) comprise the majority of stromal cells in breast cancers, yet their precise origins and relative functional contributions to malignant progression remain uncertain. Local invasion leads to the proximity of cancer cells and adipocytes, which respond by phenotypical changes to generate fibroblast-like cells termed as adipocyte-derived fibroblasts (ADF) here. These cells exhibit enhanced secretion of fibronectin and collagen I, increased migratory/invasive abilities, and increased expression of the CAF marker FSP-1 but not α-SMA. Generation of the ADF phenotype depends on reactivation of the Wnt/ß-catenin pathway in response to Wnt3a secreted by tumor cells. Tumor cells cocultivated with ADFs in two-dimensional or spheroid culture display increased invasive capabilities. In clinical specimens of breast cancer, we confirmed the presence of this new stromal subpopulation. By defining a new stromal cell population, our results offer new opportunities for stroma-targeted therapies in breast cancer.
Assuntos
Adipócitos/patologia , Neoplasias da Mama/patologia , Fibroblastos/patologia , Esferoides Celulares/patologia , Células Estromais/patologia , Microambiente Tumoral , Adipócitos/metabolismo , Animais , Western Blotting , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Movimento Celular , Proliferação de Células , Células Cultivadas , Técnicas de Cocultura , Feminino , Fibroblastos/metabolismo , Fibronectinas/genética , Fibronectinas/metabolismo , Imunofluorescência , Humanos , Técnicas Imunoenzimáticas , Camundongos , Camundongos Nus , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Proteína A4 de Ligação a Cálcio da Família S100 , Proteínas S100/genética , Proteínas S100/metabolismo , Células Estromais/metabolismo , Proteínas Wnt/genética , Proteínas Wnt/metabolismo , beta Catenina/genética , beta Catenina/metabolismoRESUMO
Cancer and type II diabetes are two diseases that appear to be associated. In fact, diabetes increases the incidence of several cancers (colon, endometrium, rectum and breast). Retrospective epidemiological studies show that metformin, a drug commonly used in type II diabetes, has antitumor properties. Therefore, many experimental studies (in vivo and in vitro) have been initiated in recent years to understand the cellular and molecular mechanisms that may explain the protective effects of metformin against cancer. Two main mode of action have been proposed. The first, indirect, involves the decrease of insulinemia. The second, via a direct action on cells, results in the regulation of the activated AMPK kinase (AMPK)/mammalian target of rapamycin (mTOR) pathway, which plays a central role in many cellular processes such as energy metabolism, protein synthesis, autophagy and apoptosis. Here, we review recent results concerning the antitumor action of metformin: epidemiological, metabolic, cellular and molecular levels. Ongoing experimental and clinical trials should help us better understand the mechanisms of action of metformin and allow us to determine whether the drug can be used in the treatment of cancer.
Assuntos
Hipoglicemiantes/uso terapêutico , Metformina/uso terapêutico , Neoplasias/tratamento farmacológico , Animais , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/epidemiologia , Reposicionamento de Medicamentos/métodos , Reposicionamento de Medicamentos/tendências , Humanos , Incidência , Neoplasias/epidemiologia , Neoplasias/etiologiaRESUMO
Among the many different cell types surrounding breast cancer cells, the most abundant are those that compose mammary adipose tissue, mainly mature adipocytes and progenitors. New accumulating recent evidences bring the tumor-surrounding adipose tissue into the light as a key component of breast cancer progression. The purpose of this review is to emphasize the role that adipose tissue might play by locally affecting breast cancer cell behavior and subsequent clinical consequences arising from this dialog. Two particular clinical aspects are addressed: obesity that was identified as an independent negative prognostic factor in breast cancer and the oncological safety of autologous fat transfer used in reconstructive surgery for breast cancer patients. This is preceded by the overall description of adipose tissue composition and function with special emphasis on the specificity of adipose depots and the species differences, key experimental aspects that need to be taken in account when cancer is considered.
Assuntos
Adipócitos/patologia , Tecido Adiposo Branco/patologia , Neoplasias da Mama/patologia , Células Epiteliais/patologia , Glândulas Mamárias Humanas/patologia , Comunicação Parácrina , Adipócitos/metabolismo , Tecido Adiposo Branco/metabolismo , Animais , Neoplasias da Mama/metabolismo , Transformação Celular Neoplásica/metabolismo , Transformação Celular Neoplásica/patologia , Progressão da Doença , Células Epiteliais/metabolismo , Feminino , Humanos , Glândulas Mamárias Humanas/metabolismo , Obesidade/metabolismo , Obesidade/patologia , Transdução de SinaisRESUMO
Early local tumor invasion in breast cancer results in a likely encounter between cancer cells and mature adipocytes, but the role of these fat cells in tumor progression remains unclear. We show that murine and human tumor cells cocultivated with mature adipocytes exhibit increased invasive capacities in vitro and in vivo, using an original two-dimensional coculture system. Likewise, adipocytes cultivated with cancer cells also exhibit an altered phenotype in terms of delipidation and decreased adipocyte markers associated with the occurrence of an activated state characterized by overexpression of proteases, including matrix metalloproteinase-11, and proinflammatory cytokines [interleukin (IL)-6, IL-1ß]. In the case of IL-6, we show that it plays a key role in the acquired proinvasive effect by tumor cells. Equally important, we confirm the presence of these modified adipocytes in human breast tumors by immunohistochemistry and quantitative PCR. Interestingly, the tumors of larger size and/or with lymph nodes involvement exhibit the higher levels of IL-6 in tumor surrounding adipocytes. Collectively, all our data provide in vitro and in vivo evidence that (i) invasive cancer cells dramatically impact surrounding adipocytes; (ii) peritumoral adipocytes exhibit a modified phenotype and specific biological features sufficient to be named cancer-associated adipocytes (CAA); and (iii) CAAs modify the cancer cell characteristics/phenotype leading to a more aggressive behavior. Our results strongly support the innovative concept that adipocytes participate in a highly complex vicious cycle orchestrated by cancer cells to promote tumor progression that might be amplified in obese patients.