Validation of an orthotopic model of human lung cancer with regional and systemic metastases

Immuno-PET Imaging of EGFR with 64Cu-NOTA Panitumumab in Subcutaneous and Metastatic Nonsmall Cell Lung Cancer Xenografts

Objective: About 65-90% of nonsmall cell lung cancer (NSCLC) express the epithelial growth factor receptor (EGFR) as a transmembrane protein that is activated by binding of specific ligands, including epidermal growth factor and transforming growth factor α (TGFα). Identifying EGFR as an oncogene has led to the development of anticancer therapeutics directed against EGFR, including the full-length human IgG2 monoclonal antibody panitumumab. The main goal of the present study was to investigate 64Cu-labeled panitumumab with immuno-PET in subcutaneous and metastatic EGFR-positive NSCLC xenografts. Methods: Bifunctional chelating agent 2-S-(4-isothiocyanatobenzyl)-1,4,7-triazacyclo-nonane-1,4,7-triacetic acid (NOTA-NCS) was attached to panitumumab. The number of chelators per panitumumab was determined using matrix-assisted laser desorption/ionization (MALDI) mass spectroscopy. The incorporation efficiency of 64Cu into NOTA-panitumumab was measured by using radio-TLC. EGFR-expressing epithelial-like H1299-luc+ NSCLC cells were used for in vitro and in vivo experiments. Cell uptake of [64Cu]Cu-NOTA-panitumumab was measured in the presence and absence of panitumumab. Subcutaneous and metastatic H1299-luc tumor models were grown in male NSG mice. The presence of tumors at lung and metastatic sites was analyzed by [18F]FLT PET. Immuno-PET with [64Cu]Cu-NOTA-panitumumab was performed as static PET imaging at 2, 24, and 48 h postinjection in both tumor models. Proof-of-target was confirmed by blocking experiments with panitumumab. Detailed ex vivo biodistribution experiments were performed in both animal tumor models to confirm biodistribution profiles obtained by immuno-PET imaging. Results: MALDI analysis confirmed the attachment of ∼1.5 NOTA per antibody. Radiolabeling efficiency with [64Cu]CuCl2 was 93.8 ± 5.7% and a molar activity of 0.65 MBq/μg. Cellular uptake studies with [64Cu]Cu-NOTA-panitumumab in H1299 cells demonstrated increasing uptake over time, reaching 29.1 ± 2.9% radioactivity(Bq)/mg protein (n = 3) and plateauing at 45 min. Addition of 25 μg of panitumumab reduced radioligand uptake to 1.22 ± 0.06% radioactivity/mg protein (n = 3). PET imaging revealed high uptake of [64Cu]Cu-NOTA-panitumumab in subcutaneous tumors: Standardized uptake values (SUV)mean reached 4.70 ± 0.42 and 5.37 ± 0.40 (n = 5) after 24 and 48 h postinjection, respectively. Administration of 1 mg panitumumab reduced tumor uptake significantly to 1.94 ± 0.22 and 1.66 ± 0.08 (n = 4; p < 0.001). In the metastatic model, the following SUVmean were analyzed from liver and lung lesions: 5.55 ± 0.34 and 6.28 ± 0.46 (both n = 23 lesions from 6 mice) after 24 and 48 h postinjection, which was also significantly reduced to 2.53 ± 0.39 and 2.31 ± 0.15 (both n = 16 lesions from 4 mice; p < 0.001) after injection of 1 mg panitumumab. Detailed ex vivo biodistribution confirmed immuno-PET analysis in both models. Panitumumab reduced radioactivity uptake into subcutaneous tumors from 11.01 ± 0.72 (n = 4) to 3.67 ± 0.33% ID/g (n = 5; p < 0.001), and in metastatic liver lesions from 29.44 ± 8.14 (n = 4) to 8.35 ± 1.30% ID/g (n = 5; p < 0.001), respectively. Conclusions: [64Cu]Cu-NOTA-panitumumab was successfully used for immuno-PET imaging of EGFR-expressing subcutaneous and metastatic NSCLC tumors. This result represents the basis for developing radiotheranostics for targeting EGFR in cancers and for selecting the right patients for the right treatment at the right time.

Potential therapeutic strategies for non - muscle invasive bladder cancer based on association of intravesical immunotherapy with p - mapa and systemic administration of cisplatin and doxorubicin

The present study describes the histopathological and molecular effects of P-MAPA (Protein aggregate magnesium-ammonium phospholinoleate-palmitoleate anhydride) intravesical immunotherapy combined with systemic doxorubicin or cisplatin for treatment of non-muscle invasive bladder cancer (NMIBC) in an appropriate animal model. Our results showed an undifferentiated tumor, characterizing a tumor invading mucosa or submucosa of the bladder wall (pT1) and papillary carcinoma in situ (pTa) in the Cancer group. The histopathological changes were similar between the combined treatment with intravesical P-MAPA plus systemic Cisplatin and P-MAPA immunotherapy alone, showing decrease of urothelial neoplastic lesions progression and histopathological recovery in 80% of the animals. The animals treated systemically with cisplatin or doxorubicin singly, showed 100% of malignant lesions in the urinary bladder. Furthemore, the combined treatment with P-MAPA and Doxorubicin showed no decrease of urothelial neoplastic lesions progression and histopathological recovery. Furthermore, Akt, PI3K, NF-kB and VEGF protein levels were significantly lower in intravesical P-MAPA plus systemic cisplatin and in intravesical P-MAPA alone treatments than other groups. In contrast, PTEN protein levels were significantly higher in intravesical P-MAPA plus systemic cisplatin and in intravesical P-MAPA alone treatments. Thus, it could be concluded that combination of intravesical P-MAPA immunotherapy and systemic cisplatin in the NMIBC animal model was effective, well tolerated and showed no apparent signs of antagonism between the drugs. In addition, intravesical P-MAPA immunotherapy may be considered as a valuable option for treatment of BCG unresponsive patients that unmet the criteria for early cystectomy.

[Study of the Changes on Tree Shrew Bronchial Epithelium Induced by Xuanwei Bituminous Coal Dust]

BACKGROUND AND OBJECTIVE

Lung cancer is the type of cancer with the highest incidence and mortality in numerous countries and regions. Establishing an appropriate animal model that can be used to simulate lung cancer etiology, pathogenesis, and similar processes, is urgent. We explore the feasibility of establishing a lung cancer model induced by Xuanwei bituminous coal dust PM10 (particulate matter with diameters of 10 μm or less), which affects bronchial epithelium of tree shrews.

METHODS

The neck skin of adult tree shrews is dissected, and the thyroid cartilage is fully exposed. Subsequently, the weak part at the top of the thyroid cartilage is treated with intratracheal agents by perfusion via a special infusion needle puncture method. Regular X-ray examination and lung tissue biopsy were performed on the sacrificed animals to observe changes in pulmonary imaging and bronchial epithelial cells after perfusion of Xuanwei bituminous coal dust PM 10.

RESULTS

The tree shrews of the experimental group (exposed to bituminous coal dust) died in a week after perfusion with PM10, whereas no animal died until the end of the experiment in the blank control and the solvent control groups. Sections of lung tissue biopsy of the regularly killed tree shrews were stained with hematoxylin and eosin. The lung tissues of tree shrews in the experimental group showed a serial changes caused by bronchial epithelial hyperplasia, such as squamous metaplasia, dysplasia, and early invasive carcinoma, whereas no significant pathological changes were observed in the blank control and solvent control groups.

CONCLUSIONS

Endotracheal infusion of Xuanwei bituminous coal dust PM10 induces lung cancer in tree shrews. Thus, the lung cancer model was established.
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[An experimental study on the Chinese lung adenocarcinoma cell clone CPA-Yang1-BR with brain metastasis potency in nude mice and in vivo imaging research]

背景与目的

肺癌脑转移是临床常见的严重并发症，由于脑部结构和功能的特殊性、脑转移检测方法的局限性，预后很差。本研究旨在筛选人肺腺癌脑转移细胞株CPA-Yang1-BR以及建立裸小鼠动物模型和检测方法。

方法

将人肺腺癌细胞株CPA-Yang1-GFP接种于裸小鼠左心室，约7周-8周后比较三种小动物显像方法：micro PET/CT显像，X线、放射性核素、荧光（三合一）活体成像系统和小动物线圈MRI显像，实验证明MRI显像是最准确的小鼠脑转移病灶检测方法。脑核磁共振成像（magnatic resonance imaging, MRI）显像找到脑转移灶，深麻醉处死裸小鼠取出脑转移病灶，部分病理验证，部分行原代培养后获得人肺腺癌脑转移细胞，再次接种裸小鼠，用上述方法重复以上体内外循环4次，观察脑转移形成情况。

结果

获得人肺腺癌脑转移细胞株CPA-Yang1-BR及其裸小鼠模型。

结论

CPA-Yang1细胞经反复裸小鼠脑组织内外筛选的方法可获得具有高转移潜能的裸小鼠脑转移模型，为肺癌脑转移的生物学研究提供了一个良好的技术平台。小动物线圈MRI或micro MRI活体显像是检测小鼠肺癌脑转移敏感、准确、无创伤的显像方法。

Pulmonary targeting microparticulate camptothecin delivery system: anticancer evaluation in a rat orthotopic lung cancer model

Large (>6 microm) rigid microparticles (MPs) become passively entrapped within the lungs after intravenous (i.v.) injection making them an attractive and highly efficient alternative to inhalation for pulmonary delivery. In this study, PEGylated 6 microm polystyrene MPs with multiple copies of the norvaline (Nva) alpha-amino acid prodrug of camptothecin (CPT) were prepared. Surface morphology was characterized using a scanning electron microscope. CPT was released from the CPT-Nva-MPs over 24 h in rat plasma at 37 degrees C. In-vivo CPT plasma concentrations were low (approximately 1 ng/ml or less) and constant over a period of 4 days after a single i.v. injection of CPT-Nva-MPs as compared with high but short-lived systemic exposures after an i.v. injection of free CPT. This suggests that sustained local CPT concentrations were achieved in the lung after administration of the MP delivery system. Anticancer efficacy was evaluated in an orthotopic lung cancer animal model and compared with a bolus injection of CPT. Animals receiving free CPT (2 mg/kg) and CPT-Nva-MPs (0.22 mg/kg CPT and 100 mg/kg MPs) were found to have statistically significant smaller areas of lung cancer (P<0.05 and 0.01, respectively) than untreated animals. In addition, 40% of the animals receiving CPT-Nva-MPs were found to be free of cancer. The CPT dose using targeted MPs was 10 times lower than after i.v. injection of free CPT, but was more effective in reducing the amount of cancerous areas. In conclusion, CPT-Nva-MPs were able to achieve effective local lung and low systemic CPT concentrations at a dose that was 10 times lower than systemically administered CPT resulting in a significant improvement in anticancer efficacy in an orthotopic rat model of lung cancer.

Experimental rat lung tumor model with intrabronchial tumor cell implantation

PURPOSE

The objective of this study was to develop a rat lung tumor model for anticancer drug testing.

METHODS

Sixty-two female Wistar rats weighing 208 +/- 20 g were anesthetized intraperitoneally with 2.5% tribromoethanol (1 ml/100 g live weight), tracheotomized and intubated with an ultrafine catheter for inoculation with Walker's tumor cells. In the first step of the experiment, a technique was established for intrabronchial implantation of 10(5) to 5 x 10(5) tumor cells, and the tumor take rate was determined. The second stage consisted of determining tumor volume, correlating findings from high-resolution computed tomography (HRCT) with findings from necropsia and determining time of survival.

RESULTS

The tumor take rate was 94.7% for implants with 4 x 10(5) tumor cells, HRCT and necropsia findings matched closely (r=0.953; p<0.0001), the median time of survival was 11 days, and surgical mortality was 4.8%.

CONCLUSION

The present rat lung tumor model was shown to be feasible: the take rate was high, surgical mortality was negligible and the procedure was simple to perform and easily reproduced. HRCT was found to be a highly accurate tool for tumor diagnosis, localization and measurement and may be recommended for monitoring tumor growth in this model.

Orthotopic Growth of Human Glioma Cells Quantitatively and Qualitatively Influences Radiation-Induced Changes in Gene Expression

The effect of radiation on gene expression has been most frequently studied using tissue culture models. To determine the influence of experimental growth condition on radiation-induced changes in gene expression, microarray analysis was done on two human glioma cell lines (U87 and U251) grown in tissue culture and as s.c. or i.c. xenografts. Compared with tissue culture, the number of genes, whose expression was affected by radiation in both cell lines, was increased in the s.c. xenografts and further increased in the orthotopic tumors. Furthermore, in each growth condition, radiation modulated the expression of a different set of genes. In addition, whereas there were few commonly affected genes after irradiation of U87 and U251 in tissue culture, there were 729 common changes after orthotopic irradiation. These results indicate that the influence of the orthotopic environment on radiation-induced modulation of gene expression in glioma cells was both quantitative and qualitative. Moreover, they suggest that investigations of the functional consequence of radiation-induced gene expression will require accounting for experimental growth conditions.

Animal models of bone metastasis

Animal models will continue to be indispensable to investigate the pathogenesis of bone metastasis in vivo, conduct preclinical chemotherapeutic, chemoprevention and genetic therapy studies, test gene delivery mechanisms, and identify metastasis suppressor and inducer genes. It is likely that the bone marrow microenvironment, such as the endothelial cells, stromal cells, hematopoietic cells, bone cells, and the intercellular matrix play important roles in the localization and clonal growth of cancer cells in bone. Given the complexity of bone metastasis, many genes are expected to be involved in the pathogenesis and few are likely indispensable. The use of genomic and proteomic approaches to study these animal models will identify key targets for therapeutic intervention. As we further refine these models and use imaging for real-time evaluation of cells, and eventually target genes, these models will more closely mirror human disease and will hopefully become more predictive of the human response to therapy.

Animal models for studying lung cancer and evaluating novel intervention strategies

The pathogenesis of lung cancer progression, invasion and metastasis remains undefined. Clinically relevant laboratory models of the disease could greatly facilitate its clarification. Model systems of lung cancer that accurately reflect different biologic properties and disease stages are necessary to ensure proper experimental design of studies aimed at increasing our understanding of the disease. Such models are also essential tools to accelerate development of new therapies for lung cancer. In this review we summarize the available lung cancer model systems in use today and define both their utility and limitations.

Adenoviral herpes simplex virus thymidine kinase gene therapy in an orthotopic lung cancer model

BACKGROUND

Although adenovirus-mediated herpes simplex virus thymidine kinase (HSVtk) gene therapy is a potential candidate for a novel effective therapy for lung cancer, previous studies have been performed only in a subcutaneous tumor model employing nude mice. We studied therapeutic potentials in correlation with accurate adenoviral gene transduction efficiency in a more clinically relevant orthotopic lung cancer model employing immunocompetent mice.

METHODS

To analyze the cytotoxicity of adenoviral HSVtk gene transduction and ganciclovir, a cell proliferation assay was performed in vitro. A survival study was carried out in immunocompetent mice with orthotopic lung cancer, which was generated by intrapulmonary inoculation with syngeneic murine lung cancer cells that had been infected beforehand with each adenoviral vector at the predetermined gene transduction efficiencies.

RESULTS

Tumor cells were efficiently killed by infection with adenovirus carrying the HSVtk gene with the addition of ganciclovir in vitro. In the in vivo experiment all control mice died of rapid growth of the primary lung cancer and of metastases to mediastinal lymph nodes within 26 days after tumor inoculation. In contrast 50% and 100% of mice survived more than 40 days after inoculation with adenovirally HSVtk-transfected tumor cells that moderately and highly expressed HSVtk, respectively, when followed by ganciclovir administration. Gene transduction efficiencies were 67%.

CONCLUSIONS

Adenovirus-mediated HSVtk gene therapy may be therapeutic for lung cancer when gene transduction efficiencies and sufficient expression levels of HSVtk can be achieved. Moreover, the present findings underscore the importance of the mouse orthotopic lung cancer model for studies of gene therapy.