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The definition of multiple myeloma (MM) was updated in 2014, with the intent to enable earlier treatment and thereby avoid appearance of end-organ damage at progression from smouldering multiple myeloma (SMM) to MM. The purpose of this study was to investigate to which extent the development of end-organ damage at progression to MM was reduced under the updated guidelines. In this prospective observational cohort study (ClinicalTrials.gov Identifier: NCT01374412), between 2014 and 2020, 96 SMM patients prospectively underwent whole-body magnetic resonance imaging (wb-MRI) and serological follow-up at baseline and every 6 months thereafter. A total of 22 patients progressed into MM during follow-up, of which seven (32%) showed SLiM-criteria only but no end-organ damage. Four (57%) of the seven patients who progressed by SLiM-criteria only progressed with >1 focal lesion (FL) or a growing FL, and three (43%) due to serum free light-chain-ratio ≥100. Fifteen (68%) out of 22 patients who progressed still suffered from end-organ damage at progression. The updated disease definition reduced the proportion of SMM patients suffering from end-organ damage at progression to MM by one third. wb-MRI is an important tool for detection of SMM patients who progress to MM without end-organ damage.
Assuntos
Mieloma Múltiplo , Mieloma Múltiplo Latente , Progressão da Doença , Seguimentos , Humanos , Imageamento por Ressonância Magnética , Mieloma Múltiplo/patologia , Estudos Prospectivos , Mieloma Múltiplo Latente/diagnóstico por imagem , Imagem Corporal TotalRESUMO
Magnetic resonance imaging is characterized by high spatial resolution and unsurpassed soft tissue discrimination. Development and characterization of both intrinsic and extrinsic magnetic resonance (MR) imaging probes in the last decade has further strengthened the pivotal role MR imaging holds in the assessment of cancer in preclinical and translational settings. Sophisticated chemical modifications of a variety of nanoparticulate probes hold the potential to deliver valuable multifunctional tools applicable in diagnostics and/or treatment in human oncology. MR imaging suffers from a lack of sensitivity achievable by, e.g., nuclear medicine imaging methods. Advantages of including additional functionality/functionalities in a probe suitable for MR imaging are thus numerous, comprising the addition of fundamentally different imaging information (diagnostics), drug delivery (therapy), or the combination of both (theranostics). In recent years, we have witnessed a plethora of preclinical multimodal or multifunctional imaging probes being published mainly as proof-of-principle studies, yet only a handful are readily applicable in clinical settings. This chapter summarizes recent innovations in the development of multifunctional MR imaging probes and discusses the suitability of these probes for clinical transfer.
Assuntos
Imageamento por Ressonância Magnética/métodos , Neoplasias/diagnóstico por imagem , HumanosRESUMO
We collected initial quantitative information on the effects of high-dose carbon (12C) ions compared to photons on vascular damage in anaplastic rat prostate tumors, with the goal of elucidating differences in response to high-LET radiation, using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Syngeneic R3327-AT1 rat prostate tumors received a single dose of either 16 or 37 Gy 12C ions or 37 or 85 Gy 6 MV photons (iso-absorbed and iso-effective doses, respectively). The animals underwent DCE-MRI prior to, and on days 3, 7, 14 and 21 postirradiation. The extended Tofts model was used for pharmacokinetic analysis. At day 21, tumors were dissected and histologically examined. The results of this work showed the following: 1. 12C ions led to stronger vascular changes compared to photons, independent of dose; 2. Tumor growth was comparable for all radiation doses and modalities until day 21; 3. Nonirradiated, rapidly growing control tumors showed a decrease in all pharmacokinetic parameters (area under the curve, Ktrans, ve, vp) over time; 4. 12C-ion-irradiated tumors showed an earlier increase in area under the curve and Ktrans than photon-irradiated tumors; 5. 12C-ion irradiation resulted in more homogeneous parameter maps and histology compared to photons; and 6. 12C-ion irradiation led to an increased microvascular density and decreased proliferation activity in a largely dose-independent manner compared to photons. Postirradiation changes related to 12C ions and photons were detected using DCE-MRI, and correlated with histological parameters in an anaplastic experimental prostate tumor. In summary, this pilot study demonstrated that exposure to 12C ions increased the perfusion and/or permeability faster and led to larger changes in DCE-MRI parameters resulting in increased vessel density and presumably less hypoxia at the end of the observation period when compared to photons. Within this study no differences were found between curative and sub-curative doses in either modality.
Assuntos
Circulação Sanguínea/efeitos da radiação , Permeabilidade Capilar/efeitos da radiação , Radioterapia com Íons Pesados , Imageamento por Ressonância Magnética , Fótons/uso terapêutico , Neoplasias da Próstata/radioterapia , Animais , Proliferação de Células/efeitos da radiação , Meios de Contraste , Relação Dose-Resposta à Radiação , Masculino , Microvasos/metabolismo , Microvasos/fisiopatologia , Microvasos/efeitos da radiação , Projetos Piloto , Neoplasias da Próstata/diagnóstico por imagem , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/fisiopatologia , Ratos , Hipóxia Tumoral/efeitos da radiaçãoRESUMO
The tumor vasculature differs from normal blood vessels in morphology, composition and stability. Here, we describe a novel tumor vessel-disrupting mechanism. In an HT1080/mouse xenograft tumor model rhodocetin-αß was highly effective in disrupting the tumor endothelial barrier. Mechanistically, rhodocetin-αß triggered MET signaling via neuropilin-1. As both neuropilin-1 and MET were only lumen-exposed in a subset of abnormal tumor vessels, but not in normal vessels, the prime target of rhodocetin-αß were these abnormal tumor vessels. Consequently, cells lining such tumor vessels became increasingly motile which compromised the vessel wall tightness. After this initial leakage, rhodocetin-αß could leave the bloodstream and reach the as yet inaccessible neuropilin-1 on the basolateral side of endothelial cells and thus disrupt nearby vessels. Due to the specific neuropilin-1/MET co-distribution on cells lining such abnormal tumor vessels in contrast to normal endothelial cells, rhodocetin-αß formed the necessary trimeric signaling complex of rhodocetin-αß-MET-neuropilin-1 only in these abnormal tumor vessels. This selective attack of tumor vessels, sparing endothelial cell-lined vessels of normal tissues, suggests that the neuropilin-1-MET signaling axis may be a promising drugable target for anti-tumor therapy, and that rhodocetin-αß may serve as a lead structure to develop novel anti-tumor drugs that target such vessels.
RESUMO
Hydrocephalus is a common congenital anomaly. LCAM1 and MPDZ (MUPP1) are the only known human gene loci associated with non-syndromic hydrocephalus. To investigate functions of the tight junction-associated protein Mpdz, we generated mouse models. Global Mpdz gene deletion or conditional inactivation in Nestin-positive cells led to formation of supratentorial hydrocephalus in the early postnatal period. Blood vessels, epithelial cells of the choroid plexus, and cilia on ependymal cells, which line the ventricular system, remained morphologically intact in Mpdz-deficient brains. However, flow of cerebrospinal fluid through the cerebral aqueduct was blocked from postnatal day 3 onward. Silencing of Mpdz expression in cultured epithelial cells impaired barrier integrity, and loss of Mpdz in astrocytes increased RhoA activity. In Mpdz-deficient mice, ependymal cells had morphologically normal tight junctions, but expression of the interacting planar cell polarity protein Pals1 was diminished and barrier integrity got progressively lost. Ependymal denudation was accompanied by reactive astrogliosis leading to aqueductal stenosis. This work provides a relevant hydrocephalus mouse model and demonstrates that Mpdz is essential to maintain integrity of the ependyma.
Assuntos
Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Modelos Animais de Doenças , Epêndima/patologia , Hidrocefalia/fisiopatologia , Animais , Astrócitos/fisiologia , Células Cultivadas , Células Epiteliais/fisiologia , Deleção de Genes , Técnicas de Silenciamento de Genes , Humanos , Proteínas de Membrana , CamundongosRESUMO
Hepatocellular carcinoma (HCC) is among the most common and deadliest cancers worldwide. A major contributor to HCC progression is the cross talk between tumor cells and the surrounding stroma including activated hepatic stellate cells (HSC). Activation of HSC during liver damage leads to upregulation of the orphan receptor endosialin (CD248), which contributes to regulating the balance of liver regeneration and fibrosis. Based on the established role of endosialin in regulating HSC/hepatocyte cross talk, we hypothesized that HSC-expressed endosialin might similarly affect cell proliferation during hepatocarcinogenesis. Indeed, the histological analysis of human HCC samples revealed an inverse correlation between tumor cell proliferation and stromal endosialin expression. Correspondingly, global genetic inactivation of endosialin resulted in accelerated tumor growth in an inducible mouse HCC model. A candidate-based screen of tumor lysates and differential protein arrays of cultured HSC identified several established hepatotropic cytokines, including IGF2, RBP4, DKK1, and CCL5 as being negatively regulated by endosialin. Taken together, the experiments identify endosialin-expressing HSC as a negative regulator of HCC progression.
Assuntos
Antígenos CD/análise , Antígenos de Neoplasias/análise , Carcinoma Hepatocelular/patologia , Proliferação de Células , Células Estreladas do Fígado/fisiologia , Hepatócitos/fisiologia , Neoplasias Hepáticas/patologia , Animais , Modelos Animais de Doenças , Humanos , Camundongos , Proteínas de Neoplasias/deficiênciaRESUMO
Personalized anti-cancer medicine is boosted by the recent development of molecular diagnostics and molecularly targeted drugs requiring rapid and efficient ligation routes. Here, we present a novel approach to synthetize a conjugate able to act simultaneously as an imaging and as a chemotherapeutic agent by coupling functional peptides employing solid phase peptide synthesis technologies. Development and the first synthesis of a fluorescent dye with similarity in the polymethine part of the Cy7 molecule whose indolenine-N residues were substituted with a propylene linker are described. Methylating agent temozolomide is functionalized with a tetrazine as a diene component whereas Cy7-cell penetrating peptide conjugate acts as a dienophilic reaction partner for the inverse Diels-Alder click chemistry-mediated ligation route yielding a theranostic conjugate, 3-mercapto-propionic-cyclohexenyl-Cy7-bis-temozolomide-bromide-cell penetrating peptide. Synthesis route described here may facilitate targeted delivery of the therapeutic compound to achieve sufficient local concentrations at the target site or tissue. Its versatility allows a choice of adequate imaging tags applicable in e.g. PET, SPECT, CT, near-infrared imaging, and therapeutic substances including cytotoxic agents. Imaging tags and therapeutics may be simultaneously bound to the conjugate applying click chemistry. Theranostic compound presented here offers a solid basis for a further improvement of cancer management in a precise, patient-specific manner.
Assuntos
Antineoplásicos/farmacocinética , Corantes Fluorescentes/farmacocinética , Técnicas de Diagnóstico Molecular/métodos , Terapia de Alvo Molecular/métodos , Neoplasias/diagnóstico , Imagem Óptica/métodos , Animais , Antineoplásicos/síntese química , Linhagem Celular Tumoral , Corantes Fluorescentes/síntese química , Medicina de Precisão/métodos , RatosRESUMO
Subcutaneously growing tumors are widely utilized to study tumor angiogenesis and the efficacy of antiangiogenic therapies in mice. To additionally assess functional and morphologic alterations of the vasculature in the periphery of a growing tumor, we exploited the easily accessible and hierarchically organized vasculature of the mouse auricle. By site-specific subcutaneous implantation of a defined preformed mouse B16/F0 melanoma aggregate, a solid tumor nodule developed within 14 d. Growth of the tumor nodule was accompanied by a 4-fold increase in its perfusion as well as a 2- to 4-fold elevated diameter and perfusion of peripheral blood vessels that had connected to the tumor capillary microvasculature. By transdermal application of the anticancer drug bortezomib, tumor growth was significantly diminished by about 50% without provoking side effects. Moreover, perfusion and tumor microvessel diameter as well as growth and perfusion of arterial or venous blood vessels supplying or draining the tumor microvasculature were decreased under these conditions by up to 80%. Collectively, we observed that the progressive tumor growth is accompanied by the enlargement of supplying and draining extratumoral blood vessels. This process was effectively suppressed by bortezomib, thereby restricting the perfusion capacity of both extra and intratumoral blood vessels.
Assuntos
Bortezomib/farmacologia , Sistemas de Liberação de Medicamentos/métodos , Neoplasias da Orelha , Melanoma , Neovascularização Patológica , Administração Cutânea , Animais , Bortezomib/efeitos adversos , Linhagem Celular Tumoral , Neoplasias da Orelha/irrigação sanguínea , Neoplasias da Orelha/tratamento farmacológico , Neoplasias da Orelha/patologia , Melanoma/irrigação sanguínea , Melanoma/tratamento farmacológico , Melanoma/patologia , Camundongos , Neovascularização Patológica/tratamento farmacológico , Neovascularização Patológica/patologiaRESUMO
Liver fibrosis is a reversible wound-healing response to injury reflecting the critical balance between liver repair and scar formation. Chronic damage leads to progressive substitution of liver parenchyma by scar tissue and ultimately results in liver cirrhosis. Stromal cells (hepatic stellate cells [HSC] and endothelial cells) have been proposed to control the balance between liver fibrosis and regeneration. Here, we show that endosialin, a C-type lectin, expressed in the liver exclusively by HSC and portal fibroblasts, is upregulated in liver fibrosis in mouse and man. Chronic chemically induced liver damage resulted in reduced fibrosis and enhanced hepatocyte proliferation in endosialin-deficient (EN(KO)) mice. Correspondingly, acute-liver-damage-induced hepatocyte proliferation (partial hepatectomy) was increased in EN(KO) mice. A candidate-based screen of known regulators of hepatocyte proliferation identified insulin-like growth factor 2 (IGF2) as selectively endosialin-dependent hepatocyte mitogen. Collectively, the study establishes a critical role of HSC in the reciprocal regulation of fibrogenesis vs. hepatocyte proliferation and identifies endosialin as a therapeutic target in non-neoplastic settings.
Assuntos
Antígenos CD/metabolismo , Antígenos de Neoplasias/metabolismo , Proliferação de Células , Células Estreladas do Fígado/metabolismo , Hepatócitos/citologia , Cirrose Hepática/patologia , Animais , Humanos , Cirrose Hepática/induzido quimicamente , Regeneração Hepática , Camundongos , Camundongos Knockout , Proteínas de Neoplasias/deficiência , Proteínas de Neoplasias/metabolismoRESUMO
The limited availability of experimental tumor models that faithfully mimic the progression of human tumors and their response to therapy remains a major bottleneck to the clinical translation and application of novel therapeutic principles. To address this challenge in hepatocellular carcinoma (HCC), one of the deadliest and most common cancers in the world, we developed and validated an inducible model of hepatocarcinogenesis in adult mice. Tumorigenesis was triggered by intravenous adenoviral delivery of Cre recombinase in transgenic mice expressing the hepatocyte-specific albumin promoter, a loxP-flanked stop cassette, and the SV40 large T-antigen (iAST). Cre recombinase-mediated excision of the stop cassette led to a transient viral hepatitis and resulted in multinodular tumorigenesis within 5 to 8 weeks. Tumor nodules with histologic characteristics of human HCC established a functional vasculature by cooption, remodeling, and angiogenic expansion of the preexisting sinusoidal liver vasculature with increasing signs of vascular immaturity during tumor progression. Treatment of mice with sorafenib rapidly resulted in the induction of vascular regression, inhibition of tumor growth, and enhanced overall survival. Vascular regression was characterized by loss of endothelial cells leaving behind avascular type IV collagen-positive empty sleeves with remaining pericytes. Sorafenib treatment led to transcriptional changes of Igf1, Id1, and cMet over time, which may reflect the emergence of potential escape mechanisms. Taken together, our results established the iAST model of inducible hepatocarcinogenesis as a robust and versatile preclinical model to study HCC progression and validate novel therapies.
Assuntos
Inibidores da Angiogênese/farmacologia , Modelos Animais de Doenças , Neoplasias Hepáticas Experimentais/irrigação sanguínea , Neoplasias Hepáticas Experimentais/tratamento farmacológico , Niacinamida/análogos & derivados , Compostos de Fenilureia/farmacologia , Animais , Humanos , Neoplasias Hepáticas Experimentais/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Niacinamida/farmacologia , SorafenibeRESUMO
Advances in imaging diagnostics using magnetic resonance tomography (MRT), positron emission tomography (PET) and fluorescence imaging including near infrared (NIR) imaging methods are facilitated by constant improvement of the concepts of peptide synthesis. Feasible patient-specific theranostic platforms in the personalized medicine are particularly dependent on efficient and clinically applicable peptide constructs. The role of peptides in the interrelations between the structure and function of proteins is widely investigated, especially by using computer-assisted methods. Nowadays the solid phase synthesis (SPPS) chemistry emerges as a key technology and is considered as a promising methodology to design peptides for the investigation of molecular pharmacological processes at the transcriptional level. SPPS syntheses could be carried out in core facilities producing peptides for large-scale scientific implementations as presented here.
Assuntos
Biomarcadores Farmacológicos/química , Ácidos Nucleicos Peptídicos/química , Peptídeos/química , Fluorescência , Humanos , Espectroscopia de Ressonância Magnética , Ácidos Nucleicos Peptídicos/síntese química , Peptídeos/síntese química , Tomografia por Emissão de Pósitrons , Técnicas de Síntese em Fase SólidaRESUMO
The transcription factor AP-1 subunit JUNB has been shown to play a pivotal role in angiogenesis. It positively controls angiogenesis by regulating Vegfa as well as the transcriptional regulator Cbfb and its target Mmp13. In line with these findings, it has been demonstrated that tumor cell-derived JUNB promotes tumor growth and angiogenesis. In contrast to JUNB's function in tumor cells, the role of host-derived stromal JUNB has not been elucidated so far. Here, we show that ablation of Junb in stromal cells including endothelial cells (ECs), vascular smooth muscle cells (SMCs) and fibroblasts does not affect tumor growth in two different syngeneic mouse models, the B16-F1 melanoma and the Lewis lung carcinoma model. In-depth analyses of the tumors revealed that tumor angiogenesis remains unaffected as assessed by measurements of the microvascular density and relative blood volume in the tumor. Furthermore, we could show that the maturation status of the tumor vasculature, analyzed by the SMC marker expression, α-smooth muscle actin and Desmin, as well as the attachment of pericytes to the endothelium, is not changed upon ablation of Junb. Taken together, these results indicate that the pro-angiogenic functions of stromal JUNB are well compensated with regard to tumor angiogenesis and tumor growth.
Assuntos
Carcinoma Pulmonar de Lewis/patologia , Melanoma Experimental/patologia , Neovascularização Patológica , Fatores de Transcrição/fisiologia , Animais , Carcinoma Pulmonar de Lewis/irrigação sanguínea , Carcinoma Pulmonar de Lewis/genética , Proliferação de Células , Endotélio Vascular/metabolismo , Endotélio Vascular/patologia , Feminino , Fibroblastos/metabolismo , Fibroblastos/patologia , Integrases/metabolismo , Imageamento por Ressonância Magnética , Masculino , Melanoma Experimental/irrigação sanguínea , Melanoma Experimental/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Músculo Liso Vascular/metabolismo , Músculo Liso Vascular/patologia , Pericitos/metabolismo , Pericitos/patologia , Células Estromais/metabolismo , Células Estromais/patologia , Fator A de Crescimento do Endotélio Vascular/metabolismoRESUMO
Angiogenesis is an essential feature of cancer growth and metastasis formation. In bone metastasis, angiogenic factors are pivotal for tumor cell proliferation in the bone marrow cavity as well as for interaction of tumor and bone cells resulting in local bone destruction. Our aim was to develop a model of experimental bone metastasis that allows in vivo assessment of angiogenesis in skeletal lesions using non-invasive imaging techniques. For this purpose, we injected 10(5) MDA-MB-231 human breast cancer cells into the superficial epigastric artery, which precludes the growth of metastases in body areas other than the respective hind leg. Following 25-30 days after tumor cell inoculation, site-specific bone metastases develop, restricted to the distal femur, proximal tibia and proximal fibula. Morphological and functional aspects of angiogenesis can be investigated longitudinally in bone metastases using magnetic resonance imaging (MRI), volumetric computed tomography (VCT) and ultrasound (US). MRI displays morphologic information on the soft tissue part of bone metastases that is initially confined to the bone marrow cavity and subsequently exceeds cortical bone while progressing. Using dynamic contrast-enhanced MRI (DCE-MRI) functional data including regional blood volume, perfusion and vessel permeability can be obtained and quantified. Bone destruction is captured in high resolution using morphological VCT imaging. Complementary to MRI findings, osteolytic lesions can be located adjacent to sites of intramedullary tumor growth. After contrast agent application, VCT angiography reveals the macrovessel architecture in bone metastases in high resolution, and DCE-VCT enables insight in the microcirculation of these lesions. US is applicable to assess morphological and functional features from skeletal lesions due to local osteolysis of cortical bone. Using B-mode and Doppler techniques, structure and perfusion of the soft tissue metastases can be evaluated, respectively. DCE-US allows for real-time imaging of vascularization in bone metastases after injection of microbubbles. In conclusion, in a model of site-specific breast cancer bone metastases multi-modal imaging techniques including MRI, VCT and US offer complementary information on morphology and functional parameters of angiogenesis in these skeletal lesions.
Assuntos
Neoplasias Ósseas/irrigação sanguínea , Neoplasias Ósseas/secundário , Neoplasias da Mama/irrigação sanguínea , Neoplasias da Mama/patologia , Animais , Neoplasias Ósseas/diagnóstico por imagem , Neoplasias da Mama/diagnóstico por imagem , Linhagem Celular Tumoral , Feminino , Humanos , Angiografia por Ressonância Magnética , Neovascularização Patológica/diagnóstico por imagem , Neovascularização Patológica/patologia , Ratos , Ratos Nus , Tomografia Computadorizada por Raios X , Transplante Heterólogo , UltrassonografiaRESUMO
OBJECTIVES: The aim of this study was to investigate the feasibility of using contrast-enhanced ultrasound (CEUS) in experimental breast cancer bone metastases and its utilization for assessment of early antiangiogenic treatment response in these lesions. MATERIALS AND METHODS: Nude rats bearing bone metastases (n = 20) were treated with the antiangiogenic tyrosine kinase inhibitor sunitinib daily from days 30 to 35 after MDA-MB-231 tumor cell inoculation (n = 10) and compared with sham-treated controls (n = 10). Imaging with ultrasound (US) and magnetic resonance imaging (MRI) was performed on days 30, 32, and 35 after tumor cell inoculation to determine tumor volume and parameters of vascularization in bone metastases. Contrast-enhanced US images were used to calculate wash-in and wash-out values, peak enhancement, and area under the curve from time intensity curves. In addition, a quantitative analysis software was used to determine regional blood volume and flow as well as filling times within bone metastases. For comparison, dynamic contrast-enhanced MRI provided amplitude A and exchange rate constant kep, respectively. Immunohistological analysis of the vasculature in bone metastases followed in vivo imaging experiments. RESULTS: Although no changes in tumor volume were assessed in the observation time, significantly decreased values for peak enhancement, area under the curve, and wash-out were determined by CEUS in animals treated with sunitinib at day 35 after tumor cell inoculation. Analysis of CEUS images with quantitative analysis software showed significantly lower values for regional blood volume and regional blood flow as well as higher values for filling time in treated animals as early as 2 days after therapy onset. Dynamic contrast-enhanced MRI revealed significantly decreased values for parameter A at day 35 and kep at days 32 and 35 after tumor cell inoculation for treated animals. Immunohistology of bone metastases revealed significantly larger vessels and decreased positive area fraction for von Willebrand Factor in animals treated with sunitinib. CONCLUSION: Contrast-enhanced US is feasible in experimental breast cancer bone metastases and depicts early antiangiogenic treatment response in advanced osteolytic lesions.
Assuntos
Inibidores da Angiogênese/uso terapêutico , Neoplasias Ósseas/secundário , Neoplasias da Mama/diagnóstico por imagem , Meios de Contraste , Osteólise , Ultrassonografia , Animais , Neoplasias Ósseas/diagnóstico por imagem , Neoplasias Ósseas/patologia , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Modelos Animais de Doenças , Estudos de Viabilidade , Feminino , Imageamento por Ressonância Magnética , Neovascularização Patológica , Ratos , Ratos Nus , Estatísticas não ParamétricasRESUMO
Bone is among the most common locations of metastasis and therefore represents an important clinical target for diagnostic follow-up in cancer patients. In the pathogenesis of bone metastases, disseminated tumor cells proliferating in bone interact with the local microenvironment stimulating or inhibiting osteoclast and osteoblast activity. Non-invasive imaging methods monitor molecular, functional and morphologic changes in both compartments of these skeletal lesions - the bone and the soft tissue tumor compartment. In the bone compartment, morphologic information on skeletal destruction is assessed by computed tomography (CT) and radiography. Pathogenic processes of osteoclast and osteoblast activity, however, can be imaged using optical imaging, positron emission tomography (PET), single photon emission CT (SPECT) and skeletal scintigraphy. Accordingly, conventional magnetic resonance imaging (MRI) and CT as well as diffusion- weighted MRI and optical imaging are used to assess morphologic aspects on the macroscopic and cellular level of the soft tissue tumor compartment. Imaging methods such as PET, MR spectroscopy, dynamic contrast-enhanced techniques and vessel size imaging further elucidate on pathogenic processes in this compartment including information on metabolism and vascularization. By monitoring these aspects in bone lesions, new insights in the pathogenesis of skeletal metastases can be gained. In translation to the clinical situation, these novel methods for the monitoring of bone metastases might be applied in patients to improve follow-up of these lesions, in particular after therapeutic intervention. This review summarizes established and experimental imaging techniques for the monitoring of tumor and bone cell activity including molecular, functional and morphological aspects in bone metastases.
Assuntos
Neoplasias Ósseas/diagnóstico , Diagnóstico por Imagem/métodos , Metástase Neoplásica/diagnóstico , Animais , Humanos , Neoplasias de Tecidos Moles/diagnósticoRESUMO
The aim of this study was the evaluation of (68)Ga-DOTA-E-[c(RGDfK)](2) as a novel PET tracer to image αvß3 and αvß5 integrins. For this purpose, DOTA-E-[c(RGDfK)](2) was labeled with (68)Ga, which was obtained from a (68)Ge/(68)Ga generator, purified by solid-phase extraction and the radiochemical purity analyzed by radio-RP-HPLC. (68) Ga-DOTA-E-[c(RGDfK)](2) was obtained reproducibly in radiochemical yields of 60 ± 6% and with an excellent radiochemical purity of >99%. In nude rats bearing bone metastases after injection of MDA-MB-231 human breast cancer cells, biodistribution studies were performed to evaluate the accumulation of the radiotracer in selected organs, blood and bone metastases 0.5, 1, 2 and 3 h post injection. A rapid uptake into the bone metastases and rapid blood clearance was observed, resulting in tumor-blood ratios of up to 26.6 (3 h post injection) and tumor-muscle ratios of up to 7.9 (3 h post injection). A blocking experiment with coinjected αvß3/αvß5 antagonist showed the tumor uptake to be receptor-specific. In an initial in vivo micro PET evaluation of the tracer using the same animal model, the bone metastasis was clearly visualized. These results suggest that (68)Ga-DOTA-E-[c(RGDfK)](2) is a promising PET tracer suitable for the imaging of αvß3 and αvß5 integrins in bone metastases. This novel PET tracer should be further evaluated concerning its usefulness for early detection of bone metastases and monitoring treatment response of these lesions.
Assuntos
Neoplasias Ósseas/diagnóstico por imagem , Neoplasias da Mama/diagnóstico por imagem , Complexos de Coordenação , Integrina alfaVbeta3/análise , Neoplasias Experimentais/diagnóstico por imagem , Peptídeos Cíclicos , Tomografia por Emissão de Pósitrons/métodos , Receptores de Vitronectina/análise , Animais , Neoplasias Ósseas/secundário , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Complexos de Coordenação/química , Complexos de Coordenação/farmacocinética , Feminino , Radioisótopos de Gálio , Humanos , Integrina alfaVbeta3/antagonistas & inibidores , Peptídeos Cíclicos/química , Peptídeos Cíclicos/farmacocinética , Traçadores Radioativos , Ratos , Receptores de Vitronectina/antagonistas & inibidores , Distribuição TecidualRESUMO
Integrins αvß3 and αvß5 are considered to play an important role in the pathogenesis of breast cancer bone metastases. This study investigates the effects of the αvß3/αvß5 integrin-specific inhibitor cilengitide during early metastatic bone colonization. The impact of cilengitide on the migration, invasion and proliferation of MDA-MB-231 human breast carcinoma cells as well as on bone resorption by osteoclasts was investigated in vitro. For in vivo experiments, nude rats were treated with cilengitide for 30 days starting one day after site-specific tumor cell inoculation in the hind leg, and the course of metastatic changes in bone was followed using flat-panel volumetric computed tomography (VCT) and magnetic resonance imaging (MRI). Vascular changes in bone metastases were investigated using dynamic contrast-enhanced (DCE-) MRI-derived parameters amplitude A and exchange rate coefficient kep. In vitro, cilengitide treatment resulted in a decrease in proliferation, migration and invasion of MDA-MB-231 cells, as well as of osteoclast activity. In vivo, the development of bone metastasis in the hind leg of rats was not prevented by adjuvant cilengitide treatment, but cilengitide reduced the volumes of osteolytic lesions and respective soft tissue tumors of developing bone metastases as assessed with VCT and MRI, respectively. DCE-MRI revealed significant changes in the A and kep parameters including decreased relative blood volume and increased vessel permeability after cilengitide treatment indicating vessel remodeling. In conclusion, during early pathogenic processes of bone colonization, cilengitide treatment exerted effects on tumor cells, osteoclasts and vasculature reducing the skeletal lesion size of experimental skeletal metastases.
Assuntos
Neoplasias Ósseas/prevenção & controle , Neoplasias Ósseas/secundário , Venenos de Serpentes/farmacologia , Animais , Neoplasias Ósseas/irrigação sanguínea , Neoplasias Ósseas/metabolismo , Reabsorção Óssea/tratamento farmacológico , Reabsorção Óssea/metabolismo , Reabsorção Óssea/patologia , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Processos de Crescimento Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Modelos Animais de Doenças , Feminino , Humanos , Imageamento por Ressonância Magnética , Invasividade Neoplásica , Osteoclastos/metabolismo , Osteoclastos/patologia , Ratos , Ratos Nus , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The purpose of this study was the assessment of the feasibility of dynamic positron emission tomography (PET) studies with fluorine-18 fluorodeoxyglucose ((18)F-FDG) to quantify effects of the cyclic Arg-Gly-Asp peptide cilengitide, which targets the ανß 3 and ανß 5 integrin receptors in rats with breast cancer bone metastases. Rats were inoculated with MDA-MB-231 breast cancer cells, followed by the development of lytic lesions in the hind leg. Rats with lytic lesions were treated with cilengitide five times weekly on a continuous basis from days 30 to 55 after tumor cell inoculation. Dynamic PET studies with (18)F-FDG were performed in untreated (n=9), controlled (n=4) and treated rats (n=6). The data were assessed using learning-machine two-tissue compartmental analysis. The (18)F-FDG kinetic parameters obtained by two-tissue compartmental model learning-machine showed significant differences when individual parameters were compared between the control group and treated animals. Quantitative assessment of the tracer kinetics and the application of classification analysis to the data provided us with evidence to identify those tumors that demonstrated effect of cilengitide treatment. The transport rate K1 and the phosphorylation rate k3 were significantly different (P=0.033 and 0.038, respectively). Classification analysis based on support vector machines ranking feature elimination of the combination of PET parameters revealed an overall accuracy of 80.0% between treated animals and the control group. We were able to identify 83.3% treated animals compared with the control group based on k2 and VB. In conclusion, the results revealed that cilengitide treatment of experimental breast cancer bone metastases had a significant therapeutic impact on (18)F-FDG kinetics.
Assuntos
Neoplasias Ósseas/diagnóstico por imagem , Neoplasias Ósseas/tratamento farmacológico , Neoplasias da Mama/patologia , Fluordesoxiglucose F18 , Tomografia por Emissão de Pósitrons , Venenos de Serpentes/uso terapêutico , Animais , Neoplasias Ósseas/metabolismo , Neoplasias Ósseas/secundário , Linhagem Celular Tumoral , Modelos Animais de Doenças , Seguimentos , Glucose/metabolismo , Humanos , Ratos , Resultado do TratamentoRESUMO
The aim of this study was to investigate the effect of inhibiting αvß(3)/α(v) ß(5) integrins by cilengitide in experimentally induced breast cancer bone metastases using noninvasive imaging techniques. For this purpose, nude rats bearing established breast cancer bone metastases were treated with cilengitide, a small molecule inhibitor of αvß(3) and αvß(5) integrins (75 mg/kg, five days per week; n = 12 rats) and compared to vehicle-treated control rats (n = 12). In a longitudinal study, conventional magnetic resonance imaging (MRI) and flat panel volumetric computed tomography were used to assess the volume of the soft tissue tumor and osteolysis, respectively, and dynamic contrast-enhanced (DCE-) MRI was performed to determine functional parameters of the tumor vasculature reflecting blood volume and blood vessel permeability. In rats treated with cilengitide, VCT and MRI showed that osteolytic lesions and the respective bone metastatic soft tissue tumors progressed more slowly than in vehicle-treated controls. DCE-MRI indicated a decrease in blood volume and an increase in vessel permeability and immunohistology revealed increased numbers of immature vessels in cilengitide-treated rats compared to vehicle controls. In conclusion, treatment of experimental breast cancer bone metastases with cilengitide resulted in pronounced antiresorptive and antitumor effects, suggesting that αvß(3)/αvß(5) inhibition may be a promising therapeutic approach for bone metastases.
Assuntos
Neoplasias Ósseas/secundário , Imageamento por Ressonância Magnética/métodos , Neoplasias Mamárias Experimentais/tratamento farmacológico , Venenos de Serpentes/uso terapêutico , Tomografia Computadorizada por Raios X/métodos , Animais , Neoplasias Ósseas/patologia , Neoplasias da Mama/metabolismo , Linhagem Celular Tumoral , Progressão da Doença , Feminino , Humanos , Integrina alfaVbeta3/metabolismo , Neoplasias Mamárias Experimentais/patologia , Ratos , Ratos Nus , Receptores de Vitronectina/metabolismoRESUMO
PURPOSE: In this study we investigated sorafenib tosylate and paclitaxel as single and combination therapies regarding their effects on tumour growth and vasculature as well as their potency to inhibit osteolysis in experimental breast cancer bone metastases. EXPERIMENTAL DESIGN: Nude rats bearing breast cancer bone metastases were treated with sorafenib tosylate (7 mg/kg, n=11), paclitaxel (5mg/kg, n=11) or the combination of both (n=10) and were compared to untreated controls (n=11). In a longitudinal study, volumes of osteolyses and respective soft tissue tumours were measured in these groups by MRI and volume CT, while changes in cellularity within bone metastases were assessed by diffusion-weighted imaging. Dynamic contrast-enhanced MRI and vessel size imaging was performed to determine changes of tumour vasculature within osseous lesions non-invasively. RESULTS: Animals treated with sorafenib tosylate or paclitaxel showed significantly reduced growth of both, the osteolytic lesions and the soft tissue tumours as well as a decreased cellularity in bone metastases compared to control rats. Effects on the tumour vasculature of these drugs included significantly reduced blood volume as well as significant changes of the vessel permeability and the mean vessel calibers. When combining sorafenib tosylate with paclitaxel for the treatment of bone metastases positive combination effects were observed, particularly on reducing vessel permeability in these lesions. CONCLUSION: The application of sorafenib tosylate monotherapy or in combination with paclitaxel is effective against experimental breast cancer bone metastases resulting in anti-angiogenic, anti-tumour and anti-resorptive effects.