In vitro assessment of radiobiology of meningioma: A pilot study.

BACKGROUND: Meningioma are the second most common brain tumors in adults and can cause significant morbidity and mortality. The scarcity of in vitro and in vivo models represents the major obstacle to understand the molecular basis of meningioma tumorigenesis. The main aim of this study was to assess a method for radiobiology of meningioma cells colture by means of well-known meningioma lines. NEW METHOD: We carried out a protocol of cells culture for irradiation of meningioma cells. We used the immortalized cell lines IOMM-Lee and CH-157 to study their radiation-reponse by means of clonogenic assays and to evaluate their proliferation and apoptosis. We irradiated the cells with different total doses using two different linear accelerators. RESULTS: We observed a more radiation resistance of the IOMM-Lee than the CH-157. Indeed, the cellular death of CH-157 was obtained at a very low dose irradiation. Moreover, we showed a dose-response effect due to the early and late apoptosis, in fact the rate of apoptotic cells is greater than that of the necrotic cells at any dose of irradiation and at any time of analysis. COMPARISON WITH EXISTING METHODS: There is not a standardized method for radiobiology of meningioma experiments. CONCLUSIONS: Our method of cells culture appears suitable for radiosensitivity studies on meningioma. We can confirm that the response to radiotherapy depends not only on irradiation features, but also on tumor radiosensitivity.

Autologous Islet Transplantation in Patients Requiring Pancreatectomy: A Broader Spectrum of Indications Beyond Chronic Pancreatitis.

Islet autotransplantation (IAT) is usually performed in patients undergoing pancreatic surgery for chronic pancreatitis. In the present series, IAT was offered also to patients undergoing pancreatic surgery for both nonmalignant and malignant diseases, having either completion pancreatectomy as treatment for severe pancreatic fistulas (n = 21) or extensive distal pancreatectomy for neoplasms of the pancreatic neck (n = 19) or pancreatoduodenectomy because of the high risk of pancreatic fistula (n = 32). Fifty-eight of 72 patients who were eligible to this broader spectrum of indication actually received IAT. There was no evidence of a higher-than-expected rate of major complications for pancreatectomy. Forty-five patients receiving IAT were still alive at the time of the last scheduled follow-up (1375 ± 365 days). Eighteen (95%) of 19 and 11 (28%) of 39 patients reached insulin independence after partial or total pancreatectomy, respectively. The metabolic results were dependent on the transplanted islet mass. Thirty-one of 58 patients had malignant diseases of the pancreas or periampullary region, and only three patients developed ex novo liver metastases after IAT (median follow-up 914 ± 382 days). Our data demonstrate the feasibility, efficacy, and safety of IAT for a broader spectrum of clinical indications beyond chronic pancreatitis.

Early effects comparison of X-rays delivered at high-dose-rate pulses by a plasma focus device and at low dose rate on human tumour cells.

A comparative study has been performed on the effects of high-dose-rate (DR) X-ray beams produced by a plasma focus device (PFMA-3), to exploit its potential medical applications (e.g. radiotherapy), and low-DR X-ray beams produced by a conventional source (XRT). Experiments have been performed at 0.5 and 2 Gy doses on a human glioblastoma cell line (T98G). Cell proliferation rate and potassium outward currents (IK) have been investigated by time lapse imaging and patch clamp recordings. The results showed that PFMA-3 irradiation has a greater capability to reduce the proliferation rate activity with respect to XRT, while it does not affect IK of T98G cells at any of the dose levels tested. XRT irradiation significantly reduces the mean IK amplitude of T98G cells only at 0.5 Gy. This work confirms that the DR, and therefore the source of radiation, is crucial for the planning and optimisation of radiotherapy applications.

Liver perfusion changes occurring during pancreatic islet engraftment: a dynamic contrast-enhanced magnetic resonance study.

The aim of this study was to investigate liver microvascular adaptation following the intraportal infusion of pancreatic islets (pancreatic islet transplantation [islet-tx]) in diabetic patients using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). DCE-MRI was performed before and 7 days after islet-tx in six diabetic patients. Initial area under curve (AUC60) and volume transfer coefficient (Ktrans) were assessed as markers of liver perfusion. Clinical and metabolic monthly follow-up was performed in all patients, considering fasting C-peptide and ß-score as main indices of graft function. High variability in the response of liver microvasculature to islet infusion was observed: two patients showed a significant reduction in liver perfusion after transplantation (pt.2: AUC60 = -23.4%, Ktrans = -31.7%; pt.4: AUC60 = -23.7%, Ktrans = -27.9%); three patients did not show any significant variation of liver perfusion and one patient showed a significant increase (pt.3: AUC60 = +31%, Ktrans = +42.8%). Interestingly, a correlation between DCE-MRI parameters and indices of graft function was observed and, in particular, both patients with DCE-MRI evidence of posttransplantation liver perfusion reduction experienced premature graft failure. Our preliminary study demonstrated that DCE-MRI may identify different adaptive responses of liver microvasculature in patients submitted to islet-tx. These different responses could have an impact on islet engraftment, although reported findings need confirmation from larger studies.

Boron uptake measurements in a rat model for Boron Neutron Capture Therapy of lung tumours.

Lung carcinoma is the leading cause of cancer mortality in the Western countries. Despite the introduction over the last few years of new therapeutic agents, survival from lung cancer has shown no discernible improvement in the last 20 years. For these reasons any efforts to find and validate new effective therapeutic procedures for lung cancer are very timely. The selective boron uptake in the tumour with respect to healthy tissues makes Boron Neutron Capture Therapy a potentially advantageous option in the treatment of tumours that affect whole vital organs, and that are surgically inoperable. To study the possibility of applying BNCT to the treatment of diffuse pulmonary tumours, an animal model for boron uptake measurements in lung metastases was developed. Both healthy and tumour-bearing rats were infused with Boronophenylalanine (BPA) and sacrificed at different time intervals after drug administration. The lungs were extracted, and prepared for boron analysis by neutron autoradiography and α-spectroscopy. The boron concentrations in tumour and normal lung were plotted as a function of the time elapsed after BPA administration. The concentration in tumour is almost constant within the error bars for all the time intervals of the experiment (1-8 h), while the curve in normal lung decreases after 4 h from BPA infusion. At 4 h, the ratio of boron concentration in tumour to boron concentration in healthy lung is higher than 3, and it stays above this level up to 8 h. Also the images of boron distribution in the samples, obtained by neutron autoradiography, show a selective absorption in the metastases.

Some considerations for the study of TGFbeta in medium of irradiated T98G cells: activation, release and consumption.

BACKGROUND: Transforming growth factor ß1 (TGFß1) has been proposed as a candidate for the transmission of radiation-induced bystander signals. AIM: To assess the influence that the presence of latent TGFß in the medium may have on the modulation of TGFß1 release and on its receptor (TGFßR2) expression after irradiation of glioblastoma cells or after treatment with medium collected from γ-irradiated cells. MATERIALS AND METHODS: T98G cells cultured with a complete medium or a serum-free medium were irradiated with 0.25 and 1 Gy and the concentration of total TGFß1 was measured. RESULTS AND CONCLUSIONS: Irradiation of cells growing with a complete medium (i.e. a medium containing latent TGFß1, LTGFß1) caused a consistent dose-dependent decrease of the TGFß1 available in the medium. When LTGFß1 was not available in the medium (i.e. a medium without serum supplement), the levels of TGFß1 increased significantly. Changes in the pattern of expression of TGFßR2 were evident only when a serum-free medium was used.

IL-8 and IL-6 bystander signalling in human glioblastoma cells exposed to gamma radiation.

BACKGROUND: Exposure of cells to ionising radiation causes the release of several factors, such as cytokines, which are likely to be involved in some biological effects occurring in the irradiated cells and in the neighbouring non-irradiated cells (i.e. bystander effect). MATERIALS AND METHODS: The release of interleukin (IL)-6 and IL-8 in the culture medium of irradiated human glioblastoma cells was investigated using an ELISA technique. Immunocytochemistry was used to investigate the expression of corresponding cell membrane receptors in irradiated cells and in cells cultured with medium collected from irradiated cells. RESULTS: The exposure to radiation determined an increase of IL-6 concentration which was dose dependent at 20 hours, whereas IL-8 release was lower than control shortly after irradiation but increased with time, in particular at the dose of 0.5. CONCLUSION: Our data suggest that these cytokines are differently modulated by radiation and are likely to play a role in the transmission of radiation-induced response, probably orchestrating the inflammatory microenvironment of the tumour.

In-vitro effects of the tyrosine kinase inhibitor imatinib on glioblastoma cell proliferation.

Glioblastoma (GBL) is the most malignant brain tumour in adults, causing the death of most patients within 9-12 months of diagnosis. Treatment is based on a combination of surgery, radiation therapy, and chemotherapy. With these treatment modalities, however, responses are extremely poor, so identification of novel treatment strategies is highly warranted. Platelet-derived growth factors (PDGF) and their receptors are commonly coexpressed in GBL, suggesting that stimulation of autocrine PDGF receptors may contribute to their growth. Interest in these receptors as drug target for glioblastoma treatment has increased with the clinical availability of the PDGFR kinase inhibitor antagonist imatinib mesylate (STI571). In this study, T98G and A172 human GBL cell lines were analysed for their sensitivity to treatment with imatinib. In particular, we focussed our attention on analysis of DNA distribution by flow cytometry at different times of incubation with different imatinib concentrations (1-30 microM: ). Our results show that imatinib induces growth arrest in T98G and A172 cells in the G(0)/G(1) phase of the cell cycle, at all the concentrations tested, as early as 24 h after treatment. However we have also seen, by means of annexin V staining, that at 20 and 30 microM: concentrations, in concomitance with a significant growth arrest in the G(0)/G(1) phase, there is an increase of apoptotic cells 48 h after treatment, suggesting that imatinib at low concentrations (1-10 microM: ) could act as a cytostatic agent whereas at high concentrations (20, 30 microM: ) it mainly behaves as a cytotoxic agent.

Influence of imatinib mesylate on radiosensitivity of astrocytoma cells.

Imatinib mesylate (STI571), an inhibitor of alpha- and beta-platelet-derived growth factor receptors (PDGFR) and other tyrosine kinases, is a well established treatment for chronic myeloid leukaemia and gastrointestinal stromal tumours. Moreover, it is under investigation for the therapy of several other malignant tumours since protein kinases are frequently mutated or otherwise deregulated in human malignancies and they serve as a target for differentiating between tumour cells and normal tissues. The objective of this study was to determine whether gamma radiation could sensitize astrocytoma cell lines to the effects of imatinib in vitro. For this purpose, T98G and MOG-G-UVW astrocytoma cells were treated with imatinib alone or in combination with gamma radiation. The clonogenic survival assays performed with the combination of imatinib with radiation demonstrated that the drug had an additive antiproliferative effect in both cell lines considered. Imatinib confered greater radiosensitivity on the T98G tumour cells effecting a significant decrease in colony formation compared with radiation alone. These data provide a rationale to further investigate the combination of imatinib with radiation, keeping in mind that this may result in unexpected toxicities that are not observed with either treatment alone.

Statistical mixture design development of digestion methods for Oyster tissue using inductively coupled plasma optical emission spectrometry for the determination of metallic ions.

The quantitative determination of chemical elements in organic or biological samples is an important analytical problem. Normally the elements to be determined in the organic matrix must be transformed into a simple inorganic form. A digestion method by heating on a block digestor has been developed for the determination of Al, As, Ba, Ca, Cd, Co, Cu, Fe, Mg, Mn, V and Zn in Oyster tissue by ICP OES. A simplex centroid statistical mixture design has been used to study the effects of changing HNO(3), HCl and H(2)O(2) reagent proportions on the digestion of these samples. Response surface and principal component analyses show that the species Ca, Cd, Cu, Fe, Mg, Mn and Zn have very similar analytical tendencies under this experiment. By means of mixture modeling maximum recoveries for these ions were predicted using 19%, 18% and 63% of the HCl, HNO(3) and H(2)O(2) pseudocomponent mixtures, respectively. This corresponds to 21.4%, 30.8% and 47.8% of the HCl, HNO(3) and H(2)O(2) commercial solutions. Furthermore the As, Co and V ions present large recoveries for these mixtures as well. The Al and Ba ion recoveries are seen to be independent of the mixture proportions. The analysis of Oyster tissue reference material (SRM 1566b - NIST) under optimized conditions at the selected wavelengths resulted in ion recoveries between 90% and 100%.

Improving the procedure for detection of intrahepatic transplanted islets by magnetic resonance imaging.

Islet transplantation is an effective therapy for restoring normoglycemia in type-1 diabetes, but long-term islet graft function is achieved only in a minority of cases. Noninvasive magnetic resonance imaging of pancreatic islets is an attractive option for "real-time" monitoring of graft evolution. So far, previous studies have been performed in the absence of a standardized labeling procedure and, besides a feasibility study in patients, the effectiveness and safety of various labeling approaches were tested only with high field magnets (4.7 T). In this study, we addressed: (a) standardization of a labeling procedure for human islets with clinically-approved contrast agent Endorem, (b) safety aspects of labeling related to inflammation and (c) quality of imaging both at 7 T and 1.5 T. We have highlighted that the ratio of Endorem/islet is crucial for reproducible labeling, with a ratio of 2.24 ug/IEQ, allowing successful in vivo imaging both with 1.5 T and 7.0 T magnets up to 143 days after intrahepatic transplant. With this standardized labeling procedure, labeled islets are neither inflamed nor more susceptible to inflammatory insults than unlabeled ones. This report represents an important contribution towards the development of a standardized and safe clinical protocol for the noninvasive imaging of transplanted islets in humans.

Immunobiological and experimental aspects of malignant astrocytoma.

Today several findings indicate that a multifactorial strategy is the best strategy for treating cancer. Although radiotherapy, chemotherapy and surgery have been differently applied to treat human gliomas, no substantial improvement in life expectancy has been observed. Starting from 1992, the goal of our studies was to obtain new biological data on malignant astrocytomas to better understand the basic biology of the tumour and these are reviewed here. Immunotherapy may represent an available method in addition to the traditional therapeutic approaches. Starting from 1991, we set up a cellular model of lymphocytes obtained from peripheral blood of healthy patients treated with interleukin-2 (IL-2) in order to study the role of IL-2 in regulating lymphocytes activation. The lymphocytes responding to IL-2 treatment, named lymphokine-activated killer (LAK) cells, have a killer non MHC restricted activity, and are able to kill autologous and allogenic glioma cells. The interaction of LAK cells with various normal and transformed targets indicates that LAK cells recognize surface structures present both on normal and transformed cells. However, only the interaction with transformed cells induces lytic events and LAK cells can act as "surgical weapons" against tumour cells independently from their cell cycle. Much recent effort has focused on identifying the immune escape mechanisms used by glioma cells, in particular the modulation of the human leukocyte antigen (HLA) and antigen processing machinery component expression. Finally, another interesting field of research that will be presented is that of new tumour biomarkers of proliferation and apoptosis, cytokine/chemokine release and cytokine/chemokine receptors.

Feasibility study on the utilization of boron neutron capture therapy (BNCT) in a rat model of diffuse lung metastases.

In order for boron neutron capture therapy (BNCT) to be eligible for application in lung tumour disease, three fundamental criteria must be fulfilled: there must be selective uptake of boron in the tumour cells with respect to surrounding healthy tissue, biological effectiveness of the radiation therapy and minimal damage or collateral effects of the irradiation on the surrounding tissues. In this study, we evaluated the biological effectiveness of BNCT by in vitro irradiation of rat colon-carcinoma cells previously incubated in boron-enriched medium. One part of these cells was re-cultured in vitro while the other was inoculated via the inferior vena cava to induce pulmonary metastases in a rat model. We observed a post-irradiation in vitro cell viability of 0.05% after 8 days of cell culture. At 4 months follow-up, all animal subjects in the treatment group that received irradiated boron-containing cells were alive. No animal survived beyond 1 month in the control group that received non-treated cells (p<0.001 Kaplan-Meier). These preliminary findings strongly suggest that BNCT has a significant lethal effect on tumour cells and post irradiation surviving cells lose their malignant capabilities in vivo. This radio-therapeutic potential warrants the investigation of in vivo BNCT for lung tumour metastases.

Neutron autoradiography imaging of selective boron uptake in human metastatic tumours.

The ability to selectively hit the tumour cells is an essential characteristic of an anti-tumour therapy. In boron neutron capture therapy (BNCT) this characteristic is based on the selective uptake of (10)B in the tumour cells with respect to normal tissues. An important step in the BNCT planning is the measurement of the boron concentration in the tissue samples, both tumour and healthy. When the tumour is spread through the healthy tissue, as in the case of metastases, the knowledge of the different kinds of tissues in the sample being analysed is crucial. If the percentage of tumour and normal tissues cannot be evaluated, the obtained concentration is a mean value depending on the composition of the different samples being measured. In this case an imaging method that could give information both on the morphology and on the spatial distribution of boron concentration in the sample would be a fundamental support. In this paper, the results of the boron uptake analysis in the tumour and in the healthy samples taken from human livers after boron phenylalanine (BPA) infusion are shown; boron imaging was performed using neutron autoradiography.

Proliferation and programmed cell death: role of p53 protein in high and low grade astrocytoma.

p53 is a cell cycle regulator that has been well-recognized as the key molecule that triggers the induction and the control of cell proliferation and apoptosis in a wide variety of tumours, including astrocytoma. Apoptosis and proliferation are two processes intimately coupled, that occur simultaneously in tumour tissue. Previous studies of the correlations between proliferation and apoptotic index with p53 expression in astrocytic tumours have remained inconclusive. The aim of this study was to investigate the correlation of p53 expression with the apoptotic index (AI) and the cell proliferation index (PI) in pilocytic astrocytoma (PA) and glioblastoma multiforme (GBM). A correlation of p53 expression with AI and PI was found in pilocytic astrocytoma but not in glioblastoma, probably because of the mutated p53 phenotype in the latter.

Exogenous platelet-derived growth factor (PDGF) induces human astrocytoma cell line proliferation.

Platelet-derived growth factor receptors (PDGFR) regulate several processes in normal cells including cellular proliferation, differentiation and migration, and are widely expressed in a variety of malignancies. In astrocytoma, PDGF ligand and receptor are often overexpressed and PDGFR activity deregulation has been linked to pathogenesis. The issue of the functional capacity of PDGFR has only occasionally been addressed in glioma cells by measuring the proliferative response induced by exogenous PDGF. In the present study, PDGFRalpha expression was evaluated in human grade 2 and 4 astrocytoma cell lines and tissue specimens by immunocytochemistry. The receptor responsiveness to exogenous PDGF was determined in astrocytoma cells with an MTT assay. It was found that astrocytoma cells express PDGFRalpha and respond to PDGF mitogenic action in a grade-dependent manner. The receptor was found to be functional since it induced cell proliferation at different ligand concentrations. We can thus conclude that the proliferative response of human astrocytoma cells is related to their malignancy and receptor status before PDGF stimulation, suggesting a role for PDGFRalpha inhibitors as blockers of malignant cell proliferation.

Surface properties and implantation site affect the capsular fibrotic overgrowth.

Transplantation of encapsulated pancreatic islets is a promising approach for the treatment of type 1 diabetes. Large-scale application of this technique, however, is hampered by insufficient biocompatibility of the capsules. In this study, we have evaluated the biocompatibility of a new synthetic material with six different chemical groups on their surface (amino, carboxy-sulfate, carboxylate, hydroxylate, sulfate, and PMMA) used for the fabrication of the microcapsules. Eight Lewis rats were inoculated with a suspension of empty capsules made for each candidate material in the retroperitoneal ileopsoas muscle and renal subcapsular space. Four weeks later kidney and muscle containing the capsules were explanted, paraffin embedded, sectioned and stained with Sirius Red and Masson's Trichrome for histological analysis. The amount of fibrosis was also ultrastructurally evaluated with scanning electron microscopy. The samples were then subjected to digitalized quantitative analysis using specific software to determine the degree of fibrotic overgrowth. The quantification of collagen deposition, calculated in proximity of the microcapsules, was expressed as a percentage of the total area and can be considered a good index for the biocompatibility, an essential prerequisite for functional pancreatic islet transplantation. The results show that subcapsular renal space is the best implantation site and the positive surface charge induces a more intense collagen synthesis.

Modelling radiation-induced bystander effect and cellular communication.

In the last 10 years evidence has accumulated on the so-called radiation-induced 'non-targeted effects' and in particular on bystander effects, consisting of damage induction in non-irradiated cells most likely following the release of soluble factors by the irradiated ones. These phenomena were observed for different biological endpoints, both lethal and non-lethal for the cell. Although the underlying mechanisms are largely unknown, it is now widely recognised that two types of cellular communication (i.e. via gap junctions and/or release of molecular messengers into the extracellular environment) play a pivotal role. Furthermore, the effects can be significantly modulated by parameters such as cell type and cell-cycle stage, cell density, time after irradiation etc. Theoretical models and simulation codes can be of help to improve our knowledge of the mechanisms, as well as to investigate the possible role of these effects in determining deviations from the linear relationship between dose and risk which is generally applied in radiation protection. In this paper three models, including an approach under development at the University of Pavia, will be presented in detail. The focus will be on the various adopted assumptions, together with their implications in terms of non-targeted radiobiological damage and, more generally, low-dose radiation risk. Comparisons with experimental data will also be discussed.

Immunohistochemical evaluation of minichromosome maintenance protein 7 in astrocytoma grading.

The minichromosome maintenance (MCM) proteins, which play an important role in eukaryotic DNA replication, represent a group of proteins that are currently under investigation as novel diagnostic tumor markers. Several studies have proved a greater reliability of MCM proteins to stain proliferating cells compared to Ki67 protein, a routinely used proliferation marker in histopathology. In the present study, the expressions of MCM7 and Ki67 were estimated in 66 primary human astrocytomas in relation to tumor grade (Grade I-IV, WHO). MCM7 significantly stained more nuclei compared to Ki67 in all the histopathological grades investigated. In addition, a stronger increase of the MCM7 labelling index, in relation to the tumor aggressiveness, was observed.

Culture medium modulates proinflammatory conditions of human pancreatic islets before transplantation.

A portion of transplanted islets is lost during engraftment as a result of stressful events, involving hypoxia and production of proinflammatory molecules by islets. Two of these molecules (monocyte chemoattractant protein-1, CCL2/MCP-1 and tissue factor, TF) are directly correlated with reduced graft function. We evaluated which factors reduce islet proinflammatory conditions. In particular the effects of different culture media supplemented with proteins or antioxidant agents on CCL2/MCP-1 and TF human islet release were evaluated. We observed that human islets after culture in final wash culture medium (FW) significantly decreased CCL2/MCP-1 release and TF production compared with CMRL and M199. These effects were independent from the type of protein added to the media (human serum, human albumin, fetal calf serum). Glutathione in FW further decreased CCL2/MCP-1 in a dose-dependent manner. Culture conditions can modulate the proinflammatory state of islets, and could be used in clinical islet transplantation to reduce inflammation during engraftment.