RESUMO
TBX3 is a member of the highly conserved family of T-box transcription factors involved in embryogenesis, organogenesis and tumor progression. While the functional role of TBX3 in tumorigenesis has been widely studied, less is known about the specific functions of the different isoforms (TBX3iso1 and TBX3iso2) which differ in their DNA-binding domain. We therefore sought to investigate the functional consequence of this highly conserved splice event as it relates to TBX3-induced tumorigenesis. By utilizing a nude mouse xenograft model, we have identified differential tumorigenic potential between TBX3 isoforms, with TBX3iso1 overexpression more commonly associated with invasive carcinoma and high tumor vascularity. Transcriptional analysis of signaling pathways altered by TBX3iso1 and TBX3iso2 overexpression revealed significant differences in angiogenesis-related genes. Importantly, osteopontin (OPN), a cancer-associated secreted phosphoprotein, was significantly up-regulated with TBX3iso1 (but not TBX3iso2) overexpression. This pattern was observed across three non/weakly-tumorigenic breast cancer cell lines (21PT, 21NT, and MCF7). Up-regulation of OPN in TBX3iso1 overexpressing cells was associated with induction of hyaluronan synthase 2 (HAS2) expression and increased retention of hyaluronan in pericellular matrices. These transcriptional changes were accompanied by the ability to induce endothelial cell vascular channel formation by conditioned media in vitro, which could be inhibited through addition of an OPN neutralizing antibody. Within the TCGA breast cancer cohort, we identified an 8.1-fold higher TBX3iso1 to TBX3iso2 transcript ratio in tumors relative to control, and this ratio was positively associated with high-tumor grade and an aggressive molecular subtype. Collectively, the described changes involving TBX3iso1-dependent promotion of angiogenesis may thus serve as an adaptive mechanism within breast cancer cells, potentially explaining differences in tumor formation rates between TBX3 isoforms in vivo. This study is the first of its kind to report significant functional differences between the two TBX3 isoforms, both in vitro and in vivo.
Assuntos
Neoplasias da Mama/metabolismo , Neovascularização Patológica/metabolismo , Isoformas de Proteínas , Proteínas com Domínio T , Animais , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Feminino , Humanos , Camundongos , Camundongos Nus , Neovascularização Patológica/patologia , Osteopontina/metabolismo , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Proteínas com Domínio T/química , Proteínas com Domínio T/genética , Proteínas com Domínio T/metabolismoRESUMO
The acquisition of cellular invasiveness by breast epithelial cells and subsequent transition from ductal carcinoma in situ (DCIS) to invasive breast cancer is a critical step in breast cancer progression. Little is known about the molecular dynamics governing this transition. We have previously shown that overexpression of the transcriptional regulator TBX3 in DCIS-like cells increases survival, growth, and invasiveness. To explore this mechanism further and assess direct transcriptional targets of TBX3 in a high-resolution, isoform-specific context, we conducted genome-wide chromatin-immunoprecipitation (ChIP) arrays coupled with transcriptomic analysis. We show that TBX3 regulates several epithelial-mesenchymal transition (EMT)-related genes, including SLUG and TWIST1. Importantly, we demonstrate that TBX3 is a direct regulator of SLUG expression, and SLUG expression is required for TBX3-induced migration and invasion. Assessing TBX3 by immunohistochemistry in early-stage (stage 0 and stage I) breast cancers revealed high expression in low-grade lesions. Within a second independent early-stage non-high-grade cohort, we observed an association between TBX3 level in the DCIS and size of the invasive focus. Additionally, there was a positive correlation between TBX3 and SLUG, and TBX3 and TWIST1 in the invasive carcinoma. Pathway analysis revealed altered expression of several proteases and their inhibitors, consistent with the ability to degrade basement membrane in vivo. These findings strongly suggest the involvement of TBX3 in the promotion of invasiveness and progression of early-stage pre-invasive breast cancer to invasive carcinoma through the low-grade molecular pathway. © 2019 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.
Assuntos
Neoplasias da Mama/metabolismo , Carcinoma Intraductal não Infiltrante/metabolismo , Transição Epitelial-Mesenquimal , Fatores de Transcrição da Família Snail/metabolismo , Proteínas com Domínio T/metabolismo , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Carcinoma Intraductal não Infiltrante/genética , Carcinoma Intraductal não Infiltrante/patologia , Linhagem Celular Tumoral , Movimento Celular , Progressão da Doença , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Pessoa de Meia-Idade , Gradação de Tumores , Invasividade Neoplásica , Estadiamento de Neoplasias , Transdução de Sinais , Fatores de Transcrição da Família Snail/genética , Proteínas com Domínio T/genética , Regulação para CimaRESUMO
Invadopodia are cell protrusions that mediate cancer cell extravasation but the microenvironmental cues and signaling factors that induce invadopodia formation during extravasation remain unclear. Using intravital imaging and loss of function experiments, we determined invadopodia contain receptors involved in chemotaxis, namely GABA receptor and EGFR. These chemotaxis capabilities are mediated in part by PAK1 which controls invadopodia responsiveness to ligands such as GABA and EGF via assembly, stability, and turnover of invadopodia in vivo. PAK1 knockdown rendered cells unresponsive to chemotactic stimuli present in the stroma, resulting in dramatically lower rates of cancer cell extravasation and metastatic colony formation compared to stimulated cancer cells. In an experimental mouse model of brain metastasis, inhibition of PAK1 significantly reduced overall tumor burden and reduced the average size of brain metastases. In summary, invadopodia contain chemotaxis receptors that can respond to microenvironmental cues to guide cancer cell extravasation, and when PAK1 is depleted, brain tropism of metastatic breast cancer cells is significantly reduced, blocking secondary colony growth at sites otherwise permissive for metastatic outgrowth.
Assuntos
Neoplasias Encefálicas/secundário , Neoplasias da Mama/patologia , Podossomos/patologia , Quinases Ativadas por p21/metabolismo , Fatores de Despolimerização de Actina/metabolismo , Animais , Neoplasias Encefálicas/patologia , Linhagem Celular Tumoral , Movimento Celular , Embrião de Galinha , Feminino , Humanos , Imageamento por Ressonância Magnética , Camundongos Nus , Cadeias Leves de Miosina/metabolismo , Fosforilação , Podossomos/química , Podossomos/metabolismo , Tropismo , Ensaios Antitumorais Modelo de Xenoenxerto , Quinases Ativadas por p21/genéticaRESUMO
OBJECTIVE: Effective targeted therapies for patients with triple-negative breast cancer (TNBC) present an unmet clinical need. There is evidence that TNBCs often have increased expression of the epidermal growth factor receptor (EGFR) and of osteopontin (OPN). OPN-mediated signaling can activate EGFR-dependent signaling pathways. Here, we assessed OPN as a potential predictive biomarker for response to anti-EGFR therapy in TNBC. RESEARCH DESIGN AND METHODS: Using two different TNBC cell lines, MDA-MB-468 and MDA-MB-231, we investigated the impact of stable expression of OPN on efficacy of the EGFR inhibitor erlotinib in vitro. RESULTS: We observed that breast cancer cells engineered to overexpress OPN are more sensitive to growth inhibition by erlotinib than control cells. The level of response was related to the level of OPN expression, possibly due to increased phosphorylation status of EGFR Tyr1068. CONCLUSIONS: These results indicate that OPN expression levels are related to sensitivity of TNBC cells to growth inhibition by erlotinib. OPN thus is a promising predictive biomarker for anti-EGFR therapy in breast cancer.
Assuntos
Cloridrato de Erlotinib/administração & dosagem , Osteopontina/metabolismo , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Antineoplásicos/administração & dosagem , Antineoplásicos/farmacologia , Biomarcadores Tumorais/metabolismo , Linhagem Celular Tumoral , Receptores ErbB/antagonistas & inibidores , Cloridrato de Erlotinib/farmacologia , Feminino , Humanos , Terapia de Alvo Molecular , Fosforilação/efeitos dos fármacos , Inibidores de Proteínas Quinases/administração & dosagem , Inibidores de Proteínas Quinases/farmacologia , Transdução de Sinais/efeitos dos fármacos , Neoplasias de Mama Triplo Negativas/patologiaRESUMO
BACKGROUND: Brain metastasis is becoming increasingly prevalent in breast cancer due to improved extra-cranial disease control. With emerging availability of modern image-guided radiation platforms, mouse models of brain metastases and small animal magnetic resonance imaging (MRI), we examined brain metastases' responses from radiotherapy in the pre-clinical setting. In this study, we employed half brain irradiation to reduce inter-subject variability in metastases dose-response evaluations. METHODS: Half brain irradiation was performed on a micro-CT/RT system in a human breast cancer (MDA-MB-231-BR) brain metastasis mouse model. Radiation induced DNA double stranded breaks in tumors and normal mouse brain tissue were quantified using γ-H2AX immunohistochemistry at 30 min (acute) and 11 days (longitudinal) after half-brain treatment for doses of 8, 16 and 24 Gy. In addition, tumor responses were assessed volumetrically with in-vivo longitudinal MRI and histologically for tumor cell density and nuclear size. RESULTS: In the acute setting, γ-H2AX staining in tumors saturated at higher doses while normal mouse brain tissue continued to increase linearly in the phosphorylation of H2AX. While γ-H2AX fluorescence intensities returned to the background level in the brain 11 days after treatment, the residual γ-H2AX phosphorylation in the radiated tumors remained elevated compared to un-irradiated contralateral tumors. With radiation, MRI-derived relative tumor growth was significantly reduced compared to the un-irradiated side. While there was no difference in MRI tumor volume growth between 16 and 24 Gy, there was a significant reduction in tumor cell density from histology with increasing dose. In the longitudinal study, nuclear size in the residual tumor cells increased significantly as the radiation dose was increased. CONCLUSIONS: Radiation damages to the DNAs in the normal brain parenchyma are resolved over time, but remain unrepaired in the treated tumors. Furthermore, there is a radiation dose response in nuclear size of surviving tumor cells. Increase in nuclear size together with unrepaired DNA damage indicated that the surviving tumor cells post radiation had continued to progress in the cell cycle with DNA replication, but failed cytokinesis. Half brain irradiation provides efficient evaluation of dose-response for cancer cell lines, a pre-requisite to perform experiments to understand radio-resistance in brain metastases.
Assuntos
Neoplasias Encefálicas/radioterapia , Neoplasias Encefálicas/secundário , Encéfalo/efeitos da radiação , Neoplasias da Mama/patologia , Irradiação Craniana/métodos , Modelos Animais de Doenças , Animais , Encéfalo/diagnóstico por imagem , Encéfalo/metabolismo , Neoplasias Encefálicas/diagnóstico por imagem , Ciclo Celular/efeitos da radiação , Linhagem Celular Tumoral , Quebras de DNA de Cadeia Dupla/efeitos da radiação , Relação Dose-Resposta à Radiação , Feminino , Histonas/metabolismo , Histonas/efeitos da radiação , Humanos , Estudos Longitudinais , Camundongos , Camundongos Nus , Fosforilação/efeitos da radiação , Tolerância a Radiação/fisiologia , Dosagem Radioterapêutica , Raios XRESUMO
BACKGROUND: The estrogen receptor (ER) is a ligand-dependant transcription factor expressed in many breast cancers and is the target of many endocrine-based cancer therapies. Genome-wide studies have shown that the ER binds to gene-specific enhancer regions in response to ß-estradiol (E2) which undergo transcription producing noncoding enhancer RNA (eRNA). While eRNAs are important for transcriptional activation of neighboring genes, the mechanism remains poorly understood. RESULTS: Using ChIP-Seq we generate a global profile of thymine DNA glycosylase (TDG), an ER coactivator that plays an essential role in DNA demethylation, in response to E2 in the MCF7 breast cancer cell line. Remarkably, we found that in response to E2 TDG localized to enhancers which also recruit ERα, RNA Pol II and other coregulators and which are marked by histone modifications indicative of active enhancers. Importantly, depletion of TDG inhibits E2-mediated transcription of eRNAs and transcription of ER-target genes. Functionally, we find that TDG both sensitizes MCF7 cells to tamoxifen-mediated cytostasis and increases migration and invasion of MCF7 cells. CONCLUSIONS: Taken together we find that TDG plays a central role in mediating transcription at a subset of enhancers and governs how MCF7 cells respond to both estrogenic and anti-estrogenic compounds and may be an effective therapeutic target.
Assuntos
Neoplasias da Mama/genética , Elementos Facilitadores Genéticos , Estradiol/farmacologia , Receptores de Estrogênio/metabolismo , Análise de Sequência de RNA/métodos , Tamoxifeno/farmacologia , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/metabolismo , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Imunoprecipitação da Cromatina , Metilação de DNA , Sinergismo Farmacológico , Feminino , Humanos , Células MCF-7 , RNA Polimerase II/genética , Timina DNA Glicosilase/genética , Sequenciamento Completo do Genoma/métodosRESUMO
Studying the complex mechanisms underlying breast cancer metastasis and therapy response necessitates relevant in vivo models, particularly syngeneic models with an intact immune system. Two syngeneic spontaneously metastatic sublines, D2A1-m1 and D2A1-m2, were generated from the poorly metastasising BALB/c-derived D2A1 cell line by serial in vivo passaging. In vivo and in vitro analyses revealed distinct and shared characteristics of the metastatic D2A1-m1 and D2A1-m2 sublines. In particular, D2A1-m1 cells are more aggressive in experimental metastasis assays, while D2A1-m2 cells are more efficient at disseminating from the primary tumour in spontaneous metastasis assays. Surprisingly, classical metastasis-associated in vitro phenotypes, such as enhanced proliferation, migration and invasion, are reduced in the sublines compared to the parental cell line. Further, evasion of immune control cannot fully explain their enhanced metastatic properties. By contrast, both sublines show increased resistance to apoptosis when cultured in non-adherent conditions and, for the D2A1-m2 subline, increased 3D tumour spheroid growth. Moreover, the enhanced spontaneous metastatic phenotype of the D2A1-m2 subline is associated with an increased ability to recruit an activated tumour stroma. The metastatic D2A1-m1 and D2A1-m2 cell lines provide additional syngeneic models for investigating the different steps of the metastatic cascade and thereby represent valuable tools for breast cancer researchers. Finally, this study highlights that morphology and cell behaviour in 2D cell-based assays cannot be used as a reliable predictor of metastatic behaviour in vivo.
Assuntos
Neoplasias Mamárias Animais/patologia , Animais , Adesão Celular , Linhagem Celular Tumoral , Bases de Dados Genéticas , Modelos Animais de Doenças , Feminino , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Hospedeiro Imunocomprometido , Neoplasias Mamárias Animais/genética , Camundongos Endogâmicos BALB C , Metástase Neoplásica , Células Estromais/metabolismo , Células Estromais/patologiaRESUMO
PURPOSE: To evaluate whether concurrent neoadjuvant radiation added to standard chemotherapy could increase the pathologic complete response (pCR) to treatment for locally advanced breast cancer (LABC). METHODS AND MATERIALS: This prospective phase 2 trial recruited 32 LABC patients from 2009 to 2011. Patients received neoadjuvant every-3-weekly 5-fluorouracil (500 mg/m2), epirubicin (100 mg/m2), and cyclophosphamide (500 mg/m2) for 3 cycles, followed by weekly docetaxel (35 mg/m2) for 9 cycles. Regional radiation (45 Gy/25 plus 5.4 Gy/5) was delivered concurrently with docetaxel, then modified radical mastectomy. Patients were matched post hoc by a blinded statistician to a concurrent cohort treated with neoadjuvant chemotherapy, modified radical mastectomy, and adjuvant regional radiation. RESULTS: Thirty of 32 patients completed treatment. Twenty-seven were successfully matched by propensity score to 81 control patients by age, stage, and molecular subtype. The concurrent chemoradiation produced a significant increase in pCR (14% vs 22%, P<.001) but no statistically significant difference in disease-free and overall survival at 3 years (respectively, 69% vs 81%, P=.186, hazard ratio 0.51; and 74% vs 89%, P=.162, hazard ratio 0.46). Toxicity included 25% of patients with grade 3 pneumonitis and 25% of patients with dermatitis, and 1 death. CONCLUSIONS: Concurrent neoadjuvant radiation added to radiosensitizing chemotherapy significantly improved pCR. A prospective randomized clinical trial is warranted to exploit the improved response seen with concurrent therapy but using another radio-sensitizing taxane, to better minimize treatment-related toxicity and determine its impact on overall survival.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias da Mama/terapia , Quimiorradioterapia/métodos , Radiossensibilizantes/uso terapêutico , Neoplasias da Mama/mortalidade , Neoplasias da Mama/patologia , Quimiorradioterapia/efeitos adversos , Quimioterapia Adjuvante/métodos , Ciclofosfamida/administração & dosagem , Dexametasona/administração & dosagem , Intervalo Livre de Doença , Docetaxel , Esquema de Medicação , Epirubicina/administração & dosagem , Feminino , Fluoruracila/administração & dosagem , Humanos , Mastectomia Radical Modificada , Pessoa de Meia-Idade , Terapia Neoadjuvante/métodos , Pontuação de Propensão , Estudos Prospectivos , Taxoides/administração & dosagemRESUMO
PURPOSE: This paper proposes a method for analyzing the first-order speckle statistics of nonlinear contrast-enhanced ultrasound images from tumors. METHODS: Contrast signal intensity is modeled as a compound distribution of exponential probability density functions with a gamma weighting function. The gamma probability weighting function serves as an approximation for log-normally distributed flow velocities in a vascular network. The model was applied to sub-harmonic bolus-injection images acquired from a mouse breast cancer xenograft model treated with murine version bevacizumab. RESULTS: The area under curve produced using the compound statistical model could more accurately discriminate anti-VEGF-treated tumors from untreated tumors than conventional contrast-enhanced ultrasound image processing. This result was validated with gold standard histological measures of microvascular density. Fractal vessel geometry was estimated using the gamma weighting function and tested against micro-CT perfusion casting. Treated tumors had a significantly lower vascular fractal dimension than control tumors. Vascular complexity estimated using the ultrasound compound statistical model performed similarly to micro-CT fractal dimension for discriminating treated from control tumors. CONCLUSION: The proposed technique can quantify tumor perfusion and provide an index of vascular complexity, making it a potentially useful addition for clinical detection of vascular normalization in anti-angiogenic trials.
Assuntos
Inibidores da Angiogênese/farmacologia , Meios de Contraste , Neoplasias Mamárias Experimentais/diagnóstico por imagem , Neoplasias Mamárias Experimentais/tratamento farmacológico , Dinâmica não Linear , Ensaios Antitumorais Modelo de Xenoenxerto , Inibidores da Angiogênese/uso terapêutico , Animais , Bevacizumab/farmacologia , Bevacizumab/uso terapêutico , Linhagem Celular Tumoral , Feminino , Humanos , Neoplasias Mamárias Experimentais/patologia , Neoplasias Mamárias Experimentais/fisiopatologia , Camundongos , Ultrassonografia , Microtomografia por Raio-XRESUMO
PURPOSE: Incidence of brain metastasis attributed to breast cancer is increasing and prognosis is poor. It is thought that disseminated dormant cancer cells persist in metastatic organs and may evade treatments, thereby facilitating a mechanism for recurrence. Radiotherapy is used to treat brain metastases clinically, but assessment has been limited to macroscopic tumor volumes detectable by clinical imaging. Here, we use cellular MRI to understand the concurrent responses of metastases and nonproliferative or slowly cycling cancer cells to radiotherapy. METHODS: MRI cell tracking was used to investigate the impact of early cranial irradiation on the fate of individual iron-labeled cancer cells and outgrowth of breast cancer brain metastases in the human MDA-MB-231-BR-HER2 cell model. RESULTS: Early whole-brain radiotherapy significantly reduced the outgrowth of metastases from individual disseminated cancer cells in treated animals compared to controls. However, the numbers of nonproliferative iron-retaining cancer cells in the brain were not significantly different. CONCLUSIONS: Radiotherapy, when given early in cancer progression, is effective in preventing the outgrowth of solitary cancer cells to brain metastases. Future studies of the nonproliferative cancer cells' clonogenic potentials are warranted, given that their persistent presence suggests that they may have evaded treatment. Magn Reson Med 78:1506-1512, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
Assuntos
Neoplasias Encefálicas , Encéfalo , Neoplasias da Mama , Rastreamento de Células/métodos , Imageamento por Ressonância Magnética/métodos , Animais , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/radioterapia , Neoplasias Encefálicas/secundário , Neoplasias da Mama/patologia , Neoplasias da Mama/radioterapia , Linhagem Celular Tumoral , Modelos Animais de Doenças , Feminino , Humanos , Camundongos , Camundongos NusRESUMO
BACKGROUND: TBX3 is a T-box transcription factor repressor that is elevated in metastatic breast cancer and is believed to promote malignancy of tumor cells, possibly by promoting cell survival and epithelial-mesenchymal transition. METHODS: The relative expression of TBX3 was assessed in the 21T cell lines which were derived from an individual patient and represent three distinct stages of breast cancer progression: 21PT, atypical ductal hyperplasia; 21NT, ductal carcinoma in situ; and 21MT-1, invasive mammary carcinoma. Two different isoforms of TBX3 (TBX3iso1 and TBX3iso2) were overexpressed to evaluate cell survival/colony forming ability, growth, and invasion in the ductal carcinoma in situ-like 21NT cell line using an in vitro Matrigel model of cancer progression. In addition, TBX3 expression was knocked down to evaluate the effects of downregulating TBX3 on the invasive mammary carcinoma-like 21MT-1 cell line. Finally, PCR array profiling was used to assess alterations in gene expression due to TBX3 overexpression in the 21NT cells. RESULTS: TBX3 is abundant in the invasive 21MT-1 cell line, while being minimally expressed in the non-invasive 21NT and 21PT cell lines. Overexpression of either TBX3iso1 or TBX3iso2 in 21NT cells resulted in increased cell survival/colony forming ability, growth vs. apoptosis and invasion in Matrigel. In contrast, short hairpin RNA-mediated knockdown of TBX3 in the 21MT-1 cells resulted in smaller colonies, with a more regular, less dispersed (less infiltrative) morphology. Array profiling of the 21NT TBX3 iso1 and iso2 transfectants showed that there are common alterations in expression of several genes involved in signal transduction, cell cycle control/cell survival, epithelial-mesenchymal transition and invasiveness. CONCLUSIONS: Overall, these results indicate that TBX3 (isoform 1 or 2) expression can promote progression in a model of early breast cancer by altering cell properties involved in cell survival/colony formation and invasiveness, as well as key regulatory and EMT/invasiveness-related gene expressions.
Assuntos
Neoplasias da Mama/patologia , Carcinoma Ductal de Mama/patologia , Carcinoma Intraductal não Infiltrante/patologia , Regulação Neoplásica da Expressão Gênica , Hiperplasia/patologia , Proteínas com Domínio T/metabolismo , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Carcinoma Ductal de Mama/genética , Carcinoma Ductal de Mama/metabolismo , Carcinoma Intraductal não Infiltrante/genética , Carcinoma Intraductal não Infiltrante/metabolismo , Colágeno , Progressão da Doença , Combinação de Medicamentos , Transição Epitelial-Mesenquimal , Feminino , Humanos , Hiperplasia/genética , Hiperplasia/metabolismo , Laminina , Invasividade Neoplásica , Isoformas de Proteínas , Proteoglicanas , RNA Interferente Pequeno/genética , Proteínas com Domínio T/antagonistas & inibidores , Proteínas com Domínio T/genética , Células Tumorais CultivadasRESUMO
INTRODUCTION: The incidence of brain metastasis due to breast cancer is increasing, and prognosis is poor. Treatment is challenging because the blood-brain barrier (BBB) limits efficacy of systemic therapies. In this work, we develop a clinically relevant whole brain radiotherapy (WBRT) plan to investigate the impact of radiation on brain metastasis development and BBB permeability in a murine model. We hypothesize that radiotherapy will decrease tumor burden and increase tumor permeability, which could offer a mechanism to increase drug uptake in brain metastases. METHODS: Contrast-enhanced magnetic resonance imaging (MRI) and high-resolution anatomical MRI were used to evaluate BBB integrity associated with brain metastases due to breast cancer in the MDA-MB-231-BR-HER2 model during their natural development. Novel image-guided microirradiation technology was employed to develop WBRT treatment plans and to investigate if this altered brain metastatic growth or permeability. Histology and immunohistochemistry were performed on whole brain slices corresponding with MRI to validate and further investigate radiological findings. RESULTS: Herein, we show successful implementation of microirradiation technology that can deliver WBRT to small animals. We further report that WBRT following diagnosis of brain metastasis can mitigate, but not eliminate, tumor growth in the MDA-MB-231-BR-HER2 model. Moreover, radiotherapy did not impact BBB permeability associated with metastases. CONCLUSIONS: Clinically relevant WBRT is not curative when delivered after MRI-detectable tumors have developed in this model. A dose of 20 Gy in 2 fractions was not sufficient to increase tumor permeability such that it could be used as a method to increase systemic drug uptake in brain metastasis.
RESUMO
The linear subtraction methods commonly used for preclinical contrast-enhanced imaging are susceptible to registration errors and motion artifacts that lead to reduced contrast-to-tissue ratios. To address this limitation, a new approach to linear contrast-enhanced ultrasound (CEUS) is proposed based on the analysis of the temporal dynamics of the speckle statistics during wash-in of a bolus injection of microbubbles. In the proposed method, the speckle signal is approximated as a mixture of temporally varying random processes, representing the microbubble signal, superimposed onto spatially heterogeneous tissue backscatter in multiple subvolumes within the region of interest. A wash-in curve is constructed by plotting the effective degrees of freedom (EDoFs) of the histogram of the speckle signal as a function of time. The proposed method is, therefore, named the EDoF method. The EDoF parameter is proportional to the shape parameter of the Nakagami distribution. Images acquired at 18 MHz from a murine mammary fat pad breast cancer xenograft model were processed using gold-standard nonlinear amplitude modulation, conventional linear subtraction, and the proposed statistical method. The EDoF method shows promise for improving the robustness of linear CEUS based on reduced frame-to-frame variability compared with the conventional linear subtraction time-intensity curves. Wash-in curve parameters estimated using the EDoF method also demonstrate higher correlation to nonlinear CEUS than the conventional linear method. The conceptual basis of the statistical method implies that EDoF wash-in curves may carry information about vascular complexity that could provide valuable new imaging biomarkers for cancer research.
RESUMO
Progression from a primary tumor to distant metastases requires extensive interactions between tumor cells and their microenvironment. The primary tumor is not only the source of metastatic cells but also can also modulate host responses to these cells, leading to an enhancement or inhibition of metastasis. Tumor-mediated stimulation of bone marrow can result in pre-metastatic niche formation and increased metastasis. However, a primary tumor can also inhibit metastasis through concomitant tumor resistance-inhibition of metastatic growth by existing tumor mass. Here, we report that the presence of a B16F10 primary tumor significantly restricted numbers and sizes of experimental lung metastases through reduction of circulating platelets and reduced formation of metastatic tumor cell-associated thrombi. Tumor-bearing mice displayed splenomegaly, correlated with primary tumor size and platelet count. Reduction in platelet numbers in tumor-bearing animals was responsible for metastatic inhibition, as restoration of platelet numbers using isolated platelets re-established both tumor cell-associated thrombus formation and experimental metastasis. Consumption of platelets due to a B16F10 primary tumor is a form of concomitant tumor resistance and demonstrates the systemic impact of a growing tumor. Understanding the interplay between primary tumors and metastases is essential, as clarification of concomitant tumor resistance mechanisms may allow inhibition of metastatic growth following tumor resection. Key messages Mice with a primary B16F10 tumor had reduced metastasis vs. mice without a primary tumor. Tumor-bearing mice had splenomegaly and fewer platelets and tumor-associated thrombi. Restoring platelets restored tumor-associated thrombi and increased metastasis. This work shows the impact that a primary tumor can have on systemic metastasis. Understanding these interactions may lead to improved ways to inhibit metastasis.
Assuntos
Neoplasias Pulmonares/secundário , Melanoma Experimental/secundário , Neoplasias Cutâneas/patologia , Animais , Linhagem Celular Tumoral , Hemostasia , Neoplasias Pulmonares/fisiopatologia , Melanoma Experimental/fisiopatologia , Camundongos Endogâmicos C57BL , Transplante de Neoplasias , Contagem de Plaquetas , Neoplasias Cutâneas/fisiopatologia , Baço/patologia , Trombose/fisiopatologiaRESUMO
Cancer cell 'invasiveness' is one of the main driving forces in cancer metastasis, and assays that quantify this key attribute of cancer cells are crucial in cancer metastasis research. The research goal of many laboratories is to elucidate the signaling pathways and effectors that are responsible for cancer cell invasion, but many of these experiments rely on in vitro methods that do not specifically simulate individual steps of the metastatic cascade. Cancer cell extravasation is arguably the most important example of invasion in the metastatic cascade, whereby a single cancer cell undergoes transendothelial migration, forming invasive processes known as invadopodia to mediate translocation of the tumor cell from the vessel lumen into tissue in vivo. We have developed a rapid, reproducible and economical technique to evaluate cancer cell invasiveness by quantifying in vivo rates of cancer cell extravasation in the chorioallantoic membrane (CAM) of chicken embryos. This technique enables the investigator to perform well-powered loss-of-function studies of cancer cell extravasation within 24 h, and it can be used to identify and validate drugs with potential antimetastatic effects that specifically target cancer cell extravasation. A key advantage of this technique over similar assays is that intravascular cancer cells within the capillary bed of the CAM are clearly distinct from extravasated cells, which makes cancer cell extravasation easy to detect. An intermediate level of experience in injections of the chorioallantoic membrane of avian embryos and cell culture techniques is required to carry out the protocol.
Assuntos
Invasividade Neoplásica/patologia , Patologia/métodos , Animais , Linhagem Celular Tumoral/patologia , Embrião de Galinha , Membrana Corioalantoide , Ensaios de Seleção de Medicamentos Antitumorais/métodos , Humanos , Microscopia Confocal , Invasividade Neoplásica/diagnóstico , Reprodutibilidade dos TestesRESUMO
BACKGROUND: Extracellular vesicles released by prostate cancer present in seminal fluid, urine, and blood may represent a non-invasive means to identify and prioritize patients with intermediate risk and high risk of prostate cancer. We hypothesize that enumeration of circulating prostate microparticles (PMPs), a type of extracellular vesicle (EV), can identify patients with Gleason Score≥4+4 prostate cancer (PCa) in a manner independent of PSA. PATIENTS AND METHODS: Plasmas from healthy volunteers, benign prostatic hyperplasia patients, and PCa patients with various Gleason score patterns were analyzed for PMPs. We used nanoscale flow cytometry to enumerate PMPs which were defined as submicron events (100-1000nm) immunoreactive to anti-PSMA mAb when compared to isotype control labeled samples. Levels of PMPs (counts/µL of plasma) were also compared to CellSearch CTC Subclasses in various PCa metastatic disease subtypes (treatment naïve, castration resistant prostate cancer) and in serially collected plasma sets from patients undergoing radical prostatectomy. RESULTS: PMP levels in plasma as enumerated by nanoscale flow cytometry are effective in distinguishing PCa patients with Gleason Score≥8 disease, a high-risk prognostic factor, from patients with Gleason Score≤7 PCa, which carries an intermediate risk of PCa recurrence. PMP levels were independent of PSA and significantly decreased after surgical resection of the prostate, demonstrating its prognostic potential for clinical follow-up. CTC subclasses did not decrease after prostatectomy and were not effective in distinguishing localized PCa patients from metastatic PCa patients. CONCLUSIONS: PMP enumeration was able to identify patients with Gleason Score ≥8 PCa but not patients with Gleason Score 4+3 PCa, but offers greater confidence than CTC counts in identifying patients with metastatic prostate cancer. CTC Subclass analysis was also not effective for post-prostatectomy follow up and for distinguishing metastatic PCa and localized PCa patients. Nanoscale flow cytometry of PMPs presents an emerging biomarker platform for various stages of prostate cancer.
Assuntos
Micropartículas Derivadas de Células/patologia , Vesículas Extracelulares/patologia , Citometria de Fluxo/métodos , Nanotecnologia , Próstata/patologia , Neoplasias da Próstata/patologia , Adulto , Anticorpos Monoclonais/imunologia , Biópsia , Estudos de Casos e Controles , Micropartículas Derivadas de Células/metabolismo , Vesículas Extracelulares/metabolismo , Seguimentos , Humanos , Masculino , Microscopia de Força Atômica , Gradação de Tumores , Estadiamento de Neoplasias , Prognóstico , Próstata/metabolismo , Próstata/cirurgia , Antígeno Prostático Específico/sangue , Prostatectomia , Hiperplasia Prostática/sangue , Hiperplasia Prostática/patologia , Hiperplasia Prostática/cirurgia , Neoplasias da Próstata/sangue , Neoplasias da Próstata/cirurgia , Neoplasias de Próstata Resistentes à Castração/sangue , Neoplasias de Próstata Resistentes à Castração/patologia , Neoplasias de Próstata Resistentes à Castração/cirurgia , Complexo de Endopeptidases do Proteassoma/imunologia , Estudos Retrospectivos , Células Tumorais Cultivadas , Adulto JovemRESUMO
PURPOSE: Small animal immobilization devices facilitate positioning of animals for reproducible imaging and accurate focal radiation therapy. In this study, the authors demonstrate the use of three-dimensional (3D) printing technology to fabricate a custom-designed mouse head restraint. The authors evaluate the accuracy of this device for the purpose of mouse brain irradiation. METHODS: A mouse head holder was designed for a microCT couch using cad software and printed in an acrylic based material. Ten mice received half-brain radiation while positioned in the 3D-printed head holder. Animal placement was achieved using on-board image guidance and computerized asymmetric collimators. To evaluate the precision of beam localization for half-brain irradiation, mice were sacrificed approximately 30 min after treatment and brain sections were stained for γ-H2AX, a marker for DNA breaks. The distance and angle of the γ-H2AX radiation beam border to longitudinal fissure were measured on histological samples. Animals were monitored for any possible trauma from the device. RESULTS: Visualization of the radiation beam on ex vivo brain sections with γ-H2AX immunohistochemical staining showed a sharp radiation field within the tissue. Measurements showed a mean irradiation targeting error of 0.14±0.09 mm (standard deviation). Rotation between the beam axis and mouse head was 1.2°±1.0° (standard deviation). The immobilization device was easily adjusted to accommodate different sizes of mice. No signs of trauma to the mice were observed from the use of tooth block and ear bars. CONCLUSIONS: The authors designed and built a novel 3D-printed mouse head holder with many desired features for accurate and reproducible radiation targeting. The 3D printing technology was found to be practical and economical for producing a small animal imaging and radiation restraint device and allows for customization for study specific needs.
Assuntos
Encéfalo/patologia , Encéfalo/efeitos da radiação , Imobilização/instrumentação , Imobilização/veterinária , Radioterapia/instrumentação , Radioterapia/veterinária , Animais , Desenho de Equipamento , Análise de Falha de Equipamento , Camundongos , Camundongos Endogâmicos C57BL , Impressão Tridimensional/instrumentação , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
Clear cell renal cell carcinoma (ccRCC) is characterized by Von Hippel-Lindau (VHL)-deficiency, resulting in pseudohypoxic, angiogenic and glycolytic tumours. Hydrogen sulfide (H2S) is an endogenously-produced gasotransmitter that accumulates under hypoxia and has been shown to be pro-angiogenic and cytoprotective in cancer. It was hypothesized that H2S levels are elevated in VHL-deficient ccRCC, contributing to survival, metabolism and angiogenesis. Using the H2S-specific probe MeRhoAz, it was found that H2S levels were higher in VHL-deficient ccRCC cell lines compared to cells with wild-type VHL. Inhibition of H2S-producing enzymes could reduce the proliferation, metabolism and survival of ccRCC cell lines, as determined by live-cell imaging, XTT/ATP assay, and flow cytometry respectively. Using the chorioallantoic membrane angiogenesis model, it was found that systemic inhibition of endogenous H2S production was able to decrease vascularization of VHL-deficient ccRCC xenografts. Endogenous H2S production is an attractive new target in ccRCC due to its involvement in multiple aspects of disease.
Assuntos
Carcinoma de Células Renais/metabolismo , Sulfeto de Hidrogênio/antagonistas & inibidores , Sulfeto de Hidrogênio/metabolismo , Animais , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Embrião de Galinha , Humanos , Sulfeto de Hidrogênio/farmacologia , Neovascularização Patológica/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
OBJECTIVES: Brain metastases due to breast cancer are increasing, and the prognosis is poor. Lack of effective therapy is attributed to heterogeneity of breast cancers and their resulting metastases, as well as impermeability of the blood-brain barrier (BBB), which hinders delivery of therapeutics to the brain. This work investigates three experimental models of HER2+ breast cancer brain metastasis to better understand the inherent heterogeneity of the disease. We use magnetic resonance imaging (MRI) to quantify brain metastatic growth and explore its relationship with BBB permeability. DESIGN: Brain metastases due to breast cancer cells (SUM190-BR3, JIMT-1-BR3, or MDA-MB-231-BR-HER2) were imaged at 3 T using balanced steady-state free precession and contrast-enhanced T1-weighted spin echo sequences. The histology and immunohistochemistry corresponding to MRI were also analyzed. RESULTS: There were differences in metastatic tumor appearance by MRI, histology, and immunohistochemistry (Ki67, CD31, CD105) across the three models. The mean volume of an MDA-MB-231-BR-HER2 tumor was significantly larger compared to other models (F2,12 = 5.845, P < .05); interestingly, this model also had a significantly higher proportion of Gd-impermeable tumors (F2,12 = 22.18, P < .0001). Ki67 staining indicated that Gd-impermeable tumors had significantly more proliferative nuclei compared to Gd-permeable tumors (t[24] = 2.389, P < .05) in the MDA-MB-231-BR-HER2 model. CD31 and CD105 staining suggested no difference in new vasculature patterns between permeable and impermeable tumors in any model. CONCLUSION: Significant heterogeneity is present in these models of brain metastases from HER2+ breast cancer. Understanding this heterogeneity, especially as it relates to BBB permeability, is important for improvement in brain metastasis detection and treatment delivery.