Combination radiotherapy in an orthotopic mouse brain tumor model

Glioblastoma multiforme (GBM) are the most common and aggressive adult primary brain tumors. In recent years there has been substantial progress in the understanding of the mechanics of tumor invasion, and direct intracerebral inoculation of tumor provides the opportunity of observing the invasive process in a physiologically appropriate environment. As far as human brain tumors are concerned, the orthotopic models currently available are established either by stereotaxic injection of cell suspensions or implantation of a solid piece of tumor through a complicated craniotomy procedure. In our technique we harvest cells from tissue culture to create a cell suspension used to implant directly into the brain. The duration of the surgery is approximately 30 minutes, and as the mouse needs to be in a constant surgical plane, an injectable anesthetic is used. The mouse is placed in a stereotaxic jig made by Stoetling (figure 1). After the surgical area is cleaned and prepared, an incision is made; and the bregma is located to determine the location of the craniotomy. The location of the craniotomy is 2 mm to the right and 1 mm rostral to the bregma. The depth is 3 mm from the surface of the skull, and cells are injected at a rate of 2 μl every 2 minutes. The skin is sutured with 5-0 PDS, and the mouse is allowed to wake up on a heating pad. From our experience, depending on the cell line, treatment can take place from 7-10 days after surgery. Drug delivery is dependent on the drug composition. For radiation treatment the mice are anesthetized, and put into a custom made jig. Lead covers the mouse's body and exposes only the brain of the mouse. The study of tumorigenesis and the evaluation of new therapies for GBM require accurate and reproducible brain tumor animal models. Thus we use this orthotopic brain model to study the interaction of the microenvironment of the brain and the tumor, to test the effectiveness of different therapeutic agents with and without radiation.     

Sensitivity of MRI tumor biomarkers to VEGFR inhibitor therapy in an orthotopic mouse glioma model

MRI biomarkers of tumor edema, vascular permeability, blood volume, and average vessel caliber are increasingly being employed to assess the efficacy of tumor therapies. However, the dependence of these biomarkers on a number of physiological factors can compromise their sensitivity and complicate the assessment of therapeutic efficacy. Here we examine the response of these MRI tumor biomarkers to cediranib, a potent vascular endothelial growth factor receptor (VEGFR) inhibitor, in an orthotopic mouse glioma model. A significant increase in the tumor volume and relative vessel caliber index (rVCI) and a slight decrease in the water apparent diffusion coefficient (ADC) were observed for both control and cediranib treated animals. This contrasts with a clinical study that observed a significant decrease in tumor rVCI, ADC and volume with cediranib therapy. While the lack of a difference between control and cediranib treated animals in these biomarker responses might suggest that cediranib has no therapeutic benefit, cediranib treated mice had a significantly increased survival. The increased survival benefit of cediranib treated animals is consistent with the significant decrease observed for cediranib treated animals in the relative cerebral blood volume (rCBV), relative microvascular blood volume (rMBV), transverse relaxation time (T2), blood vessel permeability (K(trans)), and extravascular-extracellular space (ν(e)). The differential response of pre-clinical and clinical tumors to cediranib therapy, along with the lack of a positive response for some biomarkers, indicates the importance of evaluating the whole spectrum of different tumor biomarkers to properly assess the therapeutic response and identify and interpret the therapy-induced changes in the tumor physiology.     

Establishment of orthotopic mouse superficial bladder tumor model for studies on intravesical treatments

Various animal models of bladder tumor have been developed for the preclinical evaluation of therapeutic modalities for the treatment of bladder cancers. The ideal model for the investigation of therapeutic effects of proposed novel intravesical treatments requires the mass of the implanted tumor to be confined to the urothelium of the bladder at least for the initial phase. However, previously reported bladder tumor models are not suitable for the evaluation of intravesical therapies for the treatment of superficial bladder cancer, since the muscle invasive tumors have developed from the beginnings of the experiments. These models are too aggressive to study local treatment effects. In the current study, we demonstrated that careful instillation of MBT-2 mouse bladder cancer cells into the bladder of a syngenic C3H/HeJ mouse could establish a superficial bladder tumor with an incidence of 100%. The procedure and technique for handling animals are simple for standard animal investigators. Maintenance of the in vitro conditions of MBT-2 cells without contamination of Mycoplasma and careful selection of the substrain of C3H mouse seem to be essential for stable tumor establishment. This bladder tumor model appeared to be easy to reproduce among several investigators in different institutions. The orthotopic bladder tumor model, which was confined to urothelium, lets us evaluate various intravesical treatment strategies.     

In-hospital cerebrovascular complications following orthotopic liver transplantation: A retrospective study

Background

Cerebrovascular complications are severe events following orthotopic liver transplantation (OLT). This study aimed to observe the clinical and neuroimaging features and possible risk factors of in-hospital cerebrovascular complications in the patients who underwent OLT.

Patients and methods

We retrospectively reviewed 337 consecutive patients who underwent 358 OLTs. Cerebrovascular complications were determined by clinical and neuroimaging manifestations, and the possible risk factors were analyzed in the patients with intracranial hemorrhage.

Results

Ten of 337 (3.0%) patients developed in-hospital cerebrovascular complications (8 cases experienced intracranial hemorrhage and 2 cases had cerebral infarction), and 6 of them died. The clinical presentations were similar to common stroke, but with rapid deterioration at early stage. The hematomas on brain CT scan were massive, irregular, multifocal and diffuse, and most of them were located at brain lobes and might enlarge or rebleed. Infarcts presented lacunar and multifocal lesions in basal gangliar but with possible hemorrhagic transformation. The patients with intracranial hemorrhage had older age and a more frequency of systemic infection than non-intracranial hemorrhage patients. (P = 0.011 and 0.029, respectively).

Conclusion

Posttransplant cerebrovascular complications have severe impact on outcome of the patients who received OLT. Older age and systemic infection may be the possible risk factors of in-hospital intracranial hemorrhage following OLT.     

A novel bioluminescence orthotopic mouse model for advanced lung cancer

Lung cancer is the leading cause of cancer-related death in the United States despite recent advances in our understanding of this challenging disease. An animal model for high-throughput screening of therapeutic agents for advanced lung cancer could help promote the development of more successful treatment interventions. To develop our orthotopic lung cancer model, luciferase-expressing A549 cancer cells were injected into the mediastinum of athymic nude mice. To determine whether the model would allow easy monitoring of response to therapeutic interventions, tumors were treated with 30 mg/kg Paclitaxel or were irradiated with 5 fractions of 2 Gy, and tumor burden was monitored using bioluminescence imaging. Evidence of radiation-induced lung injury was assessed using immunohistochemical staining for phospho-Smad2/3 and cleaved caspase-3. We found that tumor implantation recapitulated advanced human lung cancer as evidenced by tumor establishment and proliferation within the mediastinum. The tumor responded to Paclitaxel or radiation as shown by decreased tumor bioluminescence and improved overall survival. Immunohistochemistry revealed increased phospho-Smad2/3 and cleaved caspase-3 in irradiated lungs, consistent with radiation-induced lung injury. This orthotopic lung cancer model may help provide a method to assess therapeutic interventions in a preclinical setting that recapitulates locally advanced lung cancer.     

Neural transplantation of human MSC and NT2 cells in the twitcher mouse model

BACKGROUND: Accumulating evidence has demonstrated that the NT2 embryonal carcinoma cell line and multipotential stem cells found in BM, mesenchymal stromal cells (MSC), have the ability to differentiate into a wide variety of cell types. This study was designed to explore the efficacy of these two human stem cell types as a graft source for the treatment of demyelinating disorders such as Krabbe's disease and multiple sclerosis (MS). METHODS: We examined the engraftment and in vivo differentiation of adult MSC and NT2 cells after transplantation into two demyelinating environments, the neonatal and postnatal twitcher mouse brain. RESULTS: Both types of xenografts led to anatomical integration, without tumor formation, and remained viable in the normal and twitcher mouse brain, showing differentiation into neurons, astrocytes and oligodendrocytes. DISCUSSION: This study represents a platform for further stem cell transplantation studies in the twitcher model and potentially has important therapeutic implications.     

Intratumoral injection of dendritic and irradiated glioma cells induces anti-tumor effects in a mouse brain tumor model

Malignant astrocytoma is the most common primary brain tumor in adults. The median survival of patients with malignant astrocytomas (high-grade astrocytomas) is about 1-2 years, despite aggressive treatment that includes surgical resection, radiotherapy and cytotoxic chemotherapy. Therefore, novel therapeutic approaches are needed to prolong survival. We investigated antitumor immunity conferred by the intratumoral injection of dendritic (DC) and irradiated glioma cells (IR-GC) in a mouse brain tumor model. Intratumorally injected DC migrated to the lymph nodes and elicited systemic immunity against autologous glioma cells. In a treatment model, intratumoral injection of DC and IR-GC prolonged the survival of brain tumor-bearing mice. Efficacy was reduced when studies were performed in mice depleted of CD8(+) T cells. Administration of DC or IR-GC alone had no effect on survival of brain tumor-bearing mice. CTL activity against glioma cells from immunized mice was also stimulated by coadministration of DC and IR-GC compared with the controls. These results support the therapeutic efficacy of intratumoral injection of DC and IR-GC.     

An improved transplantation strategy for mouse mesenchymal stem cells in an acute myocardial infarction model

To develop an effective therapeutic strategy for cardiac regeneration using bone marrow mesenchymal stem cells (BM-MSCs), the primary mouse BM-MSCs (1(st) BM-MSCs) and 5(th) passage BM-MSCs from β-galactosidase transgenic mice were respectively intramyocardially transplanted into the acute myocardial infarction (AMI) model of wild type mice. At the 6(th) week, animals/tissues from the 1(st) BM-MSCs group, the 5(th) passage BM-MSCs group, control group were examined. Our results revealed that, compared to the 5(th) passage BM-MSCs, the 1(st) BM-MSCs had better therapeutic effects in the mouse MI model. The 1(st) BM-MSCs maintained greater differentiation potentials towards cardiomocytes or vascular endothelial cells in vitro. This is indicated by higher expressions of cardiomyocyte and vascular endothelial cell mature markers in vitro. Furthermore, we identified that 24 proteins were down-regulated and 3 proteins were up-regulated in the 5(th) BM-MSCs in comparison to the 1(st) BM-MSCs, using mass spectrometry following two-dimensional electrophoresis. Our data suggest that transplantation of the 1(st) BM-MSCs may be an effective therapeutic strategy for cardiac tissue regeneration following AMI, and altered protein expression profiles between the 1(st) BM-MSCs and 5(th) passage BM-MSCs may account for the difference in their maintenance of stemness and their therapeutic effects following AMI.     

BH3-mimetic drugs prevent tumour onset in an orthotopic mouse model of hepatoblastoma

Drug resistance and metastasis remain major challenges in the treatment of high-risk hepatoblastoma (HB) and require the development of alternative therapeutic strategies. Modulation of apoptosis in HB cells enhances the sensitivity of these cells towards various drugs and has been discussed to enforce treatment. We investigated the impact of apoptosis sensitisers, BH3-mimetics, on the interaction between the host and HB to reduce tumour growth and dissemination while enhancing immunity. BH3-mimetics, such as obatoclax and ABT-737, enhanced the apoptosis-inducing effect of TRAIL and TNF-α resistant HB cells (HepT1 and HUH6). Tumour cell migration was inhibited by ABT-737 and more markedly by obatoclax. In an orthotopic model of HB, tumour uptake was reduced when the cells were pretreated with low concentrations of obatoclax. Only 1 of 7 mice developed HB in the liver, compared with an incidence of 0.8 in the control group. In summary, our study showed that apoptosis sensitisers had broader effects on HB cells than expected including migration and susceptibility to cytokines in addition to the known effects on drug sensitization. Sensitising HB to apoptosis may also allow resistant HB to be targeted by immune cells and prevent tumour cell dissemination.     

An improved intrafemoral injection with minimized leakage as an orthotopic mouse model of osteosarcoma

Osteosarcoma, the most common type of primary bone cancer, is the second highest cause of cancer-related death in pediatric patients. To understand the mechanisms behind osteosarcoma progression and to discover novel therapeutic strategies for this disease, a reliable and appropriate mouse model is essential. For this purpose, osteosarcoma cells need to be injected into the bone marrow. Previously, the intratibial and intrafemoral injection methods were reported; however, the major drawback of these methods is the potential leakage of tumor cells from the injection site during or after these procedures. To overcome this, we have established an improved method to minimize leakage in an orthotopic mouse model of osteosarcoma. By taking advantage of the anatomical benefits of the femur with less bowing and larger medullary cavity than those of the tibia, osteosarcoma cells are injected directly into the femoral cavity following reaming of its intramedullary space. To prevent potential leakage of tumor cells during and after the surgery, the injection site is sealed with bone wax. This method requires a minor surgery of approximately 15 min under anesthesia. Our established orthotopic osteosarcoma model could serve as a valuable and reliable tool for examining progression of various types of bone tumors.     

In vivo preclinical low field MRI monitoring of tumor growth following a suicide gene therapy in an orthotopic mice model of human glioblastoma

Purpose

The aim of this study was to monitor in vivo with low field MRI growth of a murine orthotopic glioma model following a suicide gene therapy.

Methods

The gene therapy consisted in the stereotactic injection in the mice brain of a modified vaccinia virus Ankara (MVA) vector encoding for a suicide gene (FCU1) that transforms a non toxic prodrug 5-fluorocytosine (5-FC) to its highly cytotoxic derivatives 5-fluorouracil (5-FU) and 5’-fluorouridine-5’monophosphate (5’-FUMP). Using a warmed-up imaging cell, sequential 3D T1 and T2 0.1T MRI brain examinations were performed on 16 Swiss female nu/nu mice bearing orthotopic human glioblastoma (U87-MG cells). The 6-week in vivo MRI follow-up consisted in a weekly measurement of the intracerebral tumor volume leading to a total of 65 examinations. Mice were divided in four groups: sham group (n = 4), sham group treated with 5-FC only (n = 4), sham group with injection of MVA-FCU1 vector only (n = 4), therapy group administered with MVA-FCU1 vector and 5-FC (n = 4). Measurements of tumor volumes were obtained after manual segmentation of T1- and T2-weighted images.

Results

Intra-observer and inter-observer tumor volume measurements show no significant differences. No differences were found between T1 and T2 volume tumor doubling times between the three sham groups. A significant statistical difference (p < 0.05) in T1 and T2 volume tumor doubling times between the three sham groups and the animals treated with the intratumoral injection of MVA-FCU1 vector in combination with 2 weeks per os 5-FC administration was demonstrated.

Conclusion

Preclinical low field MRI was able to monitor efficacy of suicide gene therapy in delaying the tumor growth in an in vivo mouse model of orthotopic glioblastoma.     

小鼠Lewis肺癌原位模型的建立

目的利用Matrigel与Lewis制备细胞混悬液注射于小鼠左肺内,建立小鼠Lewis肺癌原位模型,评价其肿瘤生长情况、转移情况,以期建立更稳定、更接近于人肺癌生长情况的小鼠肺癌原位模型。方法将处于对数生长期的Lewis肺癌细胞混悬于Matrigel中,接种于C57BL/6近交系小鼠左肺内。分别于第4、7、10、13、16天各处死5只小鼠,观察其局部成瘤率、肿瘤生长情况、中位生存期及肿瘤转移情况,并对各阶段小鼠行肺部,肝脏,肾脏,脾脏病理切片检查。结果术后第7天解剖的5只小鼠中,3只小鼠肺上可见小的瘤结节形成,其余2只肺上未见肉眼成瘤,行病理HE染色检查在显微镜下可见2只小鼠肺脏有小的瘤结节形成。术后第10天以后处死的所有小鼠肺上均有肉眼成瘤,术后第13天,所有小鼠肺原位成瘤并伴有血性胸腔积液、胸腔内转移。术后第25天,有1只小鼠出现上述转移的同时还出现了心包膜转移及肾脏远处转移。5只小鼠生存期分别为17 d、20 d、22 d、22 d、25 d,小鼠中位生存期为21.2 d（17~25 d）。成瘤率100%。结论利用Matrigel法成功建立小鼠Lewis肺癌原位模型,稳定性好,成瘤率高,并具有远处转移的特性,更接近于人肺癌的发生、发展过程。     

A nucleolus-specific phosphoprotein in mouse ascites tumor cells

Analysis of proteins in nucleoli and chromatin of mouse ascites tumor cells labeled with [³²P]orthophosphate by SDS-polyacrylamide gel electrophoresis showed that a highly radioactive protein was localized in the nucleoli. This protein was purified and the final preparation appeared as a single component on hydroxylapatite column chromatography with or without SDS. This protein was found to be a nucleolus-specific phosphoprotein with a molecular weight of 120 000. The phosphate moiety in this protein turned over very rapidly whereas the protein itself was stable. When the nucleoli were disrupted by EDTA treatment, this unique protein was found as a major protein constituent of the ultracentrifugal supernatant.     

Spermatogenesis from epiblast and primordial germ cells following transplantation into postnatal mouse testis

Primordial germ cells (PGCs) are derived from a population of pluripotent epiblast cells in mice. However, little is known about when and how PGCs acquire the capacity to differentiate into functional germ cells, while keeping the potential to derive pluripotent embryonic germ cells and teratocarcinomas. In this investigation, we show that epiblast cells and PGCs can establish colonies of spermatogenesis after transfer into postnatal seminiferous tubules of surrogate infertile mice. Furthermore, we obtained normal fertile offspring by microinsemination using spermatozoa or spermatids derived from PGCs harvested from fetuses as early as 8.5 days post coitum. Thus, fetal male germ cell development is remarkably flexible, and the maturation process, from epiblast cells through PGCs to postnatal spermatogonia, can occur in the postnatal testicular environment. Primordial germ cell transplantation techniques will also provide a novel tool to assess the developmental potential of PGCs, such as those manipulated in vitro or recovered from embryos harboring lethal mutations.     

Regeneration following orthotopic transplantation of entire plantaris muscle in Sprague Dawley rats

Regeneration of rat plantaris muscle has been studied without predeneration. The original muscle fibres were completely degenerated within one week, but were completely regenerated at the end of experiment. The weight of regenerate showed 51% recovery. The breadth, length and total area of muscle and number of muscle fibres was less by 42, 37, 26 and 29% respectively, compared to control muscle at the end of experiment. The diameter of regenerated fibres was almost normalized at the end of experiment. The number and diameter of nuclei in the regenerate was more than that of control which coincides with the increase in DNA and RNA contents. The protein contents after an initial loss started increasing and continued to do so till the end of the experiment. The better regeneration of the plantaris muscle seems to be due to the presence of supporting gastrocnemius muscle.     

Recombinant canstatin inhibits tumor growth in an orthotopic AT-84 oral squamous cell carcinoma model

The inhibitory effect of recombinant canstatin on tumor growth was investigated using an orthotopic oral squamous cell carcinoma (AT-84 cells) animal (C3H/HeN) model. Recombinant canstatin from stably transfected Drosophila S2 cells was purified to homogeneity using a simple one-step Ni NTA affinity fractionation. In our oral cancer model, the final volume and weight of tumors in groups treated with purified canstatin were both reduced to 44% of values for a control group treated with PBS. Blood or lymphatic vessel densities of tumors in the canstatin-treated group were reduced to 72% and 44% of control group values, respectively. Recombinant canstatin at 20 μg/ml effectively inhibited tube formation in HUVEC and lymphatic endothelial cells. Our results show that recombinant canstatin has anti-tumoral effects against primary oral squamous cell carcinoma.     

Donor leukocyte migration following extremity transplantation in an experimental model.

In an effort to further define the immunologic mechanisms leading to acute composite-tissue allograft rejection, the migratory patterns of donor leukocytes were evaluated. Using a rat model, 52 orthotopic vascularized hindlimb transplants were performed in strains representing major histocompatibility mismatches. In order to evaluate the effect of allogeneic skin on limb rejection, all donor skin was removed in a second group of allografts. Recipient lymphoid organs were examined during the week following transplantation for antigen-presenting cells using a donor-specific class II monoclonal antibody. Donor leukocytes, with dendritic cell morphology, were identified in recipient spleen and lymph nodes draining the allograft. Significantly higher numbers of donor leukocytes were present during postoperative days 1 through 4 for both groups. Association of these important passenger leukocytes with host T-lymphocytes may represent the site of initiation of the immune response.