A review of techniques and results obtained in one laboratory by an integrated system of methods designed for routine clinical flow cytometric DNA analysis

Chemical occurrence of pesticides and transformation products in two small lentic waterbodies at the head of agricultural watersheds and biological responses in caged Gasterosteus aculeatus

Recent monitoring campaigns have revealed the presence of mixtures of pesticides and their transformation products (TP) in headwater streams situated within agricultural catchments. These observations were attributed to the use of various agrochemicals in surrounding regions. The aim of this work was to compare the application of chemical and ecotoxicological tools for assessing environmental quality in relation to pesticide and TP contamination. It was achieved by deploying these methodologies in two small lentic water bodies located at the top of two agricultural catchments, each characterized by distinct agricultural practices (ALT: organic, CHA: conventional). Additionally, the results make it possible to assess the impact of contamination on fish caged in situ. Pesticides and TP were measured in water using active and passive samplers and suspended solid particles. Eighteen biomarkers (innate immune responses, oxidative stress, biotransformation, neurotoxicity, genotoxicity, and endocrine disruption) were measured in Gasterosteus aculeatus encaged in situ. More contaminants were detected in CHA, totaling 25 compared to 14 in ALT. Despite the absence of pesticide application in the ALT watershed for the past 14 years, 7 contaminants were quantified in 100 % of the water samples. Among these contaminants, 6 were TPs (notably atrazine-2-hydroxy, present at a concentration exceeding 300 ng·L-1), and 1 was a current pesticide, prosulfocarb, whose mobility should prompt more caution and new regulations to protect adjacent ecosystems and crops. Regarding the integrated biomarker response (IBRv2), caged fish was similarly impacted in ALT and CHA. Variations in biomarker responses were highlighted depending on the site, but the results did not reveal whether one site is of better quality than the other. This outcome was likely attributed to the occurrence of contaminant mixtures in both sites. The main conclusions revealed that chemical and biological tools complement each other to better assess the environmental quality of wetlands such as ponds.

Application of the Fpg-modified comet assay on three-spined stickleback in freshwater biomonitoring: toward a multi-biomarker approach of genotoxicity

Aquatic species are exposed to a wide spectrum of substances, which can compromise their genomic integrity by inducing DNA damage or oxidative stress. Genotoxicity biomarkers as DNA strand breaks and chromosomal damages developed on sentinel species have already proved to be relevant in aquatic biomonitoring. However, these biomarkers do not reflect DNA oxidative lesions, i.e., the 8-oxodG, recognized as pre-mutagenic lesion if not or mis-repaired in human biomonitoring. The relevance to include the measure of these lesions by using the Fpg-modified comet assay on erythrocytes of the three-spined stickleback was investigated. An optimization step of the Fpg-modified comet assay considering enzyme buffer impact, Fpg concentration, and incubation time has been performed. Then, this measure was integrated in a battery of genotoxicity and cytotoxicity biomarkers (considering DNA strand breaks, DNA content variation, and cell apoptosis/necrosis and density) and applied in a freshwater monitoring program on six stations of the Artois Picardie watershed (3-week caging of control fish). These biomarkers allowed to discriminate the stations regarding the genotoxic potential of water bodies and specifically by the measure of oxidative DNA lesions, which seem to be a promising tool in environmental genotoxicity risk assessment.

AGS Gastric Cells: Antioxidant Activity and Metabolic Effects of Phenolic Extracts from Different Monocultivar Virgin Olive Oils

The effects of the phenolic compounds of extra virgin olive oil (EVOO) on AGS cells have never been studied so far, which is the aim of this study. The profiles of the main phenolic components in EVOOs, mainly secoiridoid compounds derived from the transformation of oleuropein during the olive milling process, were evaluated and compared. Oils of different origins were evaluated aiming at verifying whether chemical differences in the phenolic composition of the dry extracts played a role in the metabolism and in maintaining the cellular redox state of AGS cells. The following key enzymes of some metabolic pathways were studied: lactate dehydrogenase, enolase, pyruvate kinase, glucose 6-phosphate dehydrogenase, citrate synthase, 3-Hydroxyacyl-CoA dehydrogenase and hexokinase. As confirmed through PCA analysis, pretreatments with the dry extracts of EVOOs at different concentrations appeared to be able to counteract the enzymatic activity alterations due to oxidative stress induced by H₂O₂ 1 mM and 2 mM. The studied phytocomplexes showed the ability to protect AGS cells from oxidative damage and the secoiridoid derivatives from both oleuropein and ligstroside contributed to the observed effects. The results suggested that EVOOs with medium to high concentrations of phenols can exert this protection.

Virgin Olive Oil By-Products: Biological Activity of Phenolic Extract of Pâté on AGS Gastric Cells

Pâté is a by-product of olive oil production which represents an abundant source of phenolic compounds and can be used for food formulation, reducing its environmental impact and promoting a circular economy. In this context, the effects of a hydroalcoholic extract of pâté were evaluated for the first time in an AGS human cell line commonly used as model of gastric mucosa. Pâté was obtained from Tuscan olives; the total phenolic content was 16.6 mg/g dried extract, with verbascoside and secoiridoid derivatives as the most abundant phenols. The phenolic pâté extract did not alter viability, distribution of cell cycle phases or proliferation and migration of AGS cells at the tested concentrations. Seven enzymes were chosen to investigate the metabolic effect of the pâté extract in the context of oxidative stress. Pâté produced a statistically significant increase in the activity of key enzymes of some metabolic pathways: Lactate dehydrogenase, Enolase, Pyruvate kinase, Glucose 6-phosphate dehydrogenase, Citrate synthase, 3-Hydroxyacyl-CoA dehydrogenase and Hexokinase. Pre-treatments with the extract of pâté at 100 µg/mL or 200 µg/mL, as observed through PCA analysis, appeared able to counteract the enzymatic activity alterations due to oxidative stress induced by H₂O₂ 1 mM and 2 mM. The results indicate that dried pâté, due to its phenolic components, can be proposed as a new functional food ingredient.

Integration of Genotoxic Biomarkers in Environmental Biomonitoring Analysis Using a Multi-Biomarker Approach in Three-Spined Stickleback (Gasterosteus aculeatus Linnaeus, 1758)

Water is impacted by a variety of increasing pressures, such as contaminants, including genotoxic pollutants. The proposed multi-biomarker approach at a sub-individual level gives a complementary indicator to the chemical and ecological parameters of the Water Framework Directive (WFD, 2000/60/EC). By integrating biomarkers of genotoxicity and erythrocyte necrosis in the sentinel fish species the three-spined stickleback (Gasterosteus aculeatus) through active biomonitoring of six stations of the Artois-Picardie watershed, north France, our work aimed to improve the already existing biomarker approach. Even if fish in all stations had high levels of DNA strand breaks, the multivariate analysis (PCA), followed by hierarchical agglomerative clustering (HAC), improved discrimination among stations by detecting an increase of nuclear DNA content variation (Etaing, St Rémy du Nord, Artres and Biache-St-Vaast) and erythrocyte necrosis (Etaing, St Rémy du Nord). The present work highlighted that the integration of these biomarkers of genotoxicity in a multi-biomarker approach is appropriate to expand physiological parameters which allow the targeting of new potential effects of contaminants.

Multicolor flow cytometry immunophenotyping and characterization of aneuploidy in pediatric B-cell precursor acute lymphoblastic leukemia

The aim of this study was to assess the incidence of DNA aneuploidy in Polish children with B-cell precursor acute lymphoblastic leukemia (BCP-ALL) and the relationship between aneuploidy and immunological phenotype, age, leukocyte count, S-phase fraction (SPF) and early response to induction chemotherapy assessed by the percentage of residual blast cells in bone marrow aspirates. The study group consisted of 267 patients. DNA content and immunophenotype were assessed in the bone marrow before treatment using multicolor flow cytometry (FC). DNA aneuploidy was detected in 50/267 (19%) patients. High hyperdiploidy was found to be associated with lower leukocyte count (p = 0.006) and common ALL immunophenotype. Flow cytometry analysis revealed that high hyperdiploid BCP-ALL patients showed significantly higher expression of CD9, CD20, CD22, CD58, CD66c, CD86 and CD123 antigens as compared to other groups of ploidy. In contrast, CD45 showed decreased expression. The percentage of leukemic blasts at diagnosis was lower in high hyperdiploid BCP-ALL cases than in diploid (79% vs. 85.7%, p = 0.001). The difference in minimal residual disease (MRD) levels on day 15 and 33 of induction therapy between analyzed groups was not significant.

This study showed that high hyperdiploidy is associated with lower WBC count and specific immunological phenotype. Flow cytometric evaluation of expression of selected antigens can be used for fast identification of markers of aneuploidy in pediatric BCP-ALL, before genetic tests results are available. Understanding the biological significance of aneuploidy in leukemia can potentially be exploited therapeutically using targeted therapies against specific blast cell subclones.

Combination Therapy of TRAIL and Thymoquinone Induce Breast Cancer Cell Cytotoxicity-Mediated Apoptosis and Cell Cycle Arrest

OBJECTIVE

Cancer is one of the leading causes of mortality in both developed and developing nations. The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is characterized by its ability to selectively trigger apoptosis in cancer cells. TRAIL-based interventions have led to the development of recombinant human (rhTRAIL) as a promising therapy for different types of human cancer. Thymoquinone (TQ) has been shown to exert anticancer effect. The aim of the current study is to investigate the anticancer effect of the combinatorial therapy of TRAIL+TQ against human breast cancer cells.

METHODS

To achieve this hypothesis, cytotoxicity using MTT assay, as well as apoptosis and cell cycle using flow cytometric technique were preceded against breast cancer MCF-7 and MDA-MB-231 cancerous cell lines.

RESULTS

The current study showed that TRAIL induced cell cycle arrest and apoptosis. Moreover, it inhibited proliferation of MDA-MB-231 cells more than MCF-7 cells. Adding TQ to TRAIL increased the chemo-sensitivity of MDA-MB-231, while overcame the MCF-7 resistance to TRAIL.

CONCLUSION

In conclusion, there is a synergistic effect between TRAIL and TQ playing a therapeutic role in killing resistant breast cancer cells.

In situ cell cycle analysis in giant cell tumor of bone reveals patients with elevated risk of reduced progression-free survival

OBJECTIVE

Giant cell tumor of bone (GCTB) is a frequently recurring locally aggressive osteolytic lesion, where pathological osteoclastogenesis and bone destruction are driven by neoplastic stromal cells. Here, we studied if cell cycle fractions within the mononuclear cell compartment of GCTB can predict its progression-free survival (PFS).

METHODS

154 cases (100 primaries and 54 recurrent) from 139 patients of 40 progression events, was studied using tissue microarrays. Ploidy and in situ cell cycle progression related proteins including Ki67 and those linked with replication licensing (mcm2), G1-phase (cyclin D1, Cdk4), and S-G2-M-phase (cyclin A; Cdk2) fractions; cell cycle control (p21^waf1) and repression (geminin), were tested. The Prentice-Williams-Peterson (PWP) gap-time models with the Akaike information criterion (AIC) were used for PFS analysis.

RESULTS

Cluster analysis showed good correlation between functionally related marker positive cell fractions indicating no major cell cycle arrested cell populations in GCTB. Increasing hazard of progression was statistically associated with the elevated post-G1/S-phase cell fractions. Univariate analysis revealed significant negative association of poly-/aneuploidy (p < 0.0001), and elevated cyclin A (p < 0.001), geminin (p = 0.015), mcm2 (p = 0.016), cyclin D1 (p = 0.022) and Ki67 (B56: p = 0.0543; and Mib1: p = 0.0564 -strong trend) positive cell fractions with PFS. The highest-ranked multivariate interaction model (AIC = 269.5) also included ploidy (HR 5.68, 95%CI: 2.62-12.31, p < 0.0001), mcm2 (p = 0.609), cyclin D1 (HR 1.89, 95%CI: 0.88-4.09, p = 0.105) and cyclin A (p < 0.0001). The first and second best prognostic models without interaction (AIC = 271.6) and the sensitivity analysis (AIC = 265.7) further confirmed the prognostic relevance of combining these markers.

CONCLUSION

Ploidy and elevated replication licensing (mcm2), G1-phase (cyclin D1) and post-G1 phase (cyclin A) marker positive cell fractions, indicating enhanced cell cycle progression, can assist in identifying GCTB patients with increased risk for a reduced PFS.

Side effects of intra-gastric photodynamic therapy: an in vitro study

Since many years it has been acknowledged that some bacterial species, among which H. pylori, P. aeruginosa, P. acnes accumulate endogenous photosensitizers (PS) in the form of porphyrins. This makes antibacterial photodynamic therapy (PDT) easier to perform due to the possible avoidance of external PS. In this study, we focus on gastric infections associated with the presence of Helicobacter pylori (H. pylori), known to accumulate and release both protoporphyrin IX (PPIX) and coproporphyrins. PDT versus H. pylori can be carried out by modified endoscopes or by new ingestible luminous devices under development. In both cases of in vitro and in vivo applications, either for therapy (PDT) or diagnosis, scientific literature lacks studies on the possible side-effects of light treatments on the surrounding tissues. To this aim we evaluated in vitro side-effects due to a possible intrinsic photosensitivity of gastric mucosa or to a photosensitization by the PS released from the bacterium itself. Photo-toxicity studies were conducted on the AGS cell line (ATCC® CRL-1739™), commonly used as a model for the stomach mucosa tissue, considering PPIX as the photosensitizing agent. After first evaluations of PPIX dark toxicity, its uptake and accumulation sites, photo-toxicity tests were conducted using a LED light source peaked at 400 nm, by varying both PPIX concentration (50 nM - 2 μM) and light dose in the range 0.6-13 J/cm², representing different treatment procedures found in literature. The oxidative stress consequent to irradiation was investigated both in terms of ROS production and assessment of the activity of enzymes involved in ROS-related biological mechanisms. A significant phototoxic effect was found only for PPIX concentration > 100 nM for all tested light doses. This indicates that the evaluated photo-treatments do not cause side effects even with the sensitization due to PPIX released by the bacteria.

Ploidy and Proliferation Evaluated by Flow Cytometry. An Overview of Techniques and Impact in Oncology

Flow cytometric methods for the assessment of nuclear and chromosomal DNA content and of cell proliferation (including methods based on pulse-chase of bromodeoxyuridine and on monoclonal antibodies against nuclear oncoproteins and proliferation-associated antigens) are illustrated by examples and analyzed critically. The impact of most of these techniques for the study of human solid tumors, with exception of nuclear DNA content evaluation, appears still limited. In particular, new studies of cell lines and clinical material from human tumors using new proliferation markers and multiparameter flow cytometry are necessary to solve a considerable number of methodologic and scientific problems.

Assessment of HDACi-Induced Cytotoxicity

The chromatin contains the genetic and the epigenetic information of a eukaryotic organism. Posttranslational modifications of histones, such as acetylation and methylation, regulate their structure and control gene expression. Histone acetyltransferases (HATs) acetylate lysine residues in histones while histone deacetylases (HDACs) remove this modification. HDAC inhibitors (HDACi) can alter gene expression patterns and induce cytotoxicity in cancer cells. Here we provide an overview of methods to determine the cytotoxic effects of HDACi treatment. Our chapter describes colorimetric methods, like trypan blue exclusion test, crystal violet staining, lactate dehydrogenase assay, MTT and Alamar Blue assays, as well as fluorogenic methods like TUNEL staining and the caspase-3/7 activity assay. Moreover, we summarize flow cytometric analysis of propidium iodide uptake, annexin V staining, cell cycle status, ROS levels, and mitochondrial membrane potential as well as detection of apoptosis by Western blot.

Effect of cell phone-like electromagnetic radiation on primary human thyroid cells

PURPOSE

To evaluate the potential carcinogenic effects of radiofrequency energy (RFE) emitted by cell phones on human thyroid primary cells.

MATERIALS AND METHODS

Primary thyroid cell culture was prepared from normal thyroid tissue obtained from patients who underwent surgery at our department. Subconfluent thyroid cells were irradiated under different conditions inside a cell incubator using a device that simulates cell phone-RFE. Proliferation of control and irradiated cells was assessed by the immunohistochemical staining of antigen Kiel clone-67 (Ki-67) and tumor suppressor p53 (p53) expression. DNA ploidy and the stress biomarkers heat shock protein 70 (HSP70) and reactive oxygen species (ROS) was evaluated by fluorescence-activated cell sorting (FACS).

RESULTS

Our cells highly expressed thyroglobulin (Tg) and sodium-iodide symporter (NIS) confirming the origin of the tissue. None of the irradiation conditions evaluated here had an effect neither on the proliferation marker Ki-67 nor on p53 expression. DNA ploidy was also not affected by RFE, as well as the expression of the biomarkers HSP70 and ROS.

CONCLUSION

Our conditions of RFE exposure seem to have no potential carcinogenic effect on human thyroid cells. Moreover, common biomarkers usually associated to environmental stress also remained unchanged. We failed to find an association between cell phone-RFE and thyroid cancer. Additional studies are recommended.

Responses of juvenile European flounder (Platichthys flesus) to multistress in the Vilaine estuary, during a 6-month survey

Physiological and genetic responses of age 0+ Platichthys flesus were investigated in the eutrophicated and moderately contaminated Vilaine estuary, during a 6-month survey. The main objective of this study was to explore the biological responses of fishes during their juvenile period in an estuarine system in order to detect a possible selective pressure induced by the environmental stress. Our results showed a general convergence in physiological responses along the survey: an increase in genotoxicity was associated with an increase in mRNA expression of ATPase and betaine homocysteine methyltransferase. These results could suggest an increase of cellular damage, energetic request, and detoxification rate related to the growing exposure time to stress. Considering the aging of the cohort, the genetic characteristics of the Vilaine flounder cohort came closer to the one observed in a highly stressed system, the Seine estuary, suggesting a potential selective pressure mainly induced by the chemical stress.

Hyperdiploidy with 58-66 chromosomes in childhood B-acute lymphoblastic leukemia is highly curable: 58951 CLG-EORTC results

The aim of our study was to analyze the factors contributing to heterogeneity of prognosis in patients with hyperdiploidy>50 chromosomes (HD>50), a group of B-cell precursor acute lymphoblastic leukemia with favorable outcome. The 541 HD>50 patients registered prospectively in the 58951 European Organisation for Research and Treatment of Cancer (EORTC) Children's Leukemia Group (CLG) trial, identified by karyotype (446 patients) and by DNA index (DI) (490 patients), had a 6-year event-free survival (EFS) of 89.0% (standard error [SE] = 1.5%) and a 6-year overall survival (OS) of 95.9% (SE = 0.9%). The strongest prognostic factor was the modal number of chromosomes (MNC): the 6-year EFS of 51-53, 54-57, and 58-66 MNC groups were 80%, 89%, and 99%, respectively (P < .0001). Ploidy assessed by DI was also a favorable factor: the higher the DI, the better the outcome. The 6-year EFS of the 3 subgroups of DI < 1.16/≥1.16-<1.24/≥1.24 were 83%, 90%, and 95%, respectively (P = .009). All usual combinations of trisomies (chromosomes 4, 10, 17, 18) were significant favorable factors but had lower EFS when MNC was lower than 58. In multivariate analysis, MNC remained the strongest factor. Consequently, the best indicator for excellent outcome was ploidy assessed by karyotype because patients with 58-66 chromosomes stood every chance of being cured (OS of 100% at 6-year follow-up) with less-intensive therapy. This trial was registered at www.clinicaltrials.gov as #NCT00003728. Registered: http://www.eortc.org/, http://clinicaltrials.gov/show/NCT00003728.

Cardiac stem cell senescence

Cellular senescence processes affecting tissue resident stem cells are considered, at present, an hallmark of both aging and age-related pathologies. Therefore it is mandatory to address this problem with adequate techniques that could highlight the molecular alterations associated with this complex cellular response to stressors. Here we describe methods to characterize cardiac stem cell (CSC) senescence from a molecular and functional standpoint.

Quantitative analysis of survivin protein expression and its therapeutic depletion by an antisense oligonucleotide in human lung tumors

RNA-directed antisense and interference therapeutics are a promising treatment option for cancer. The demonstration of depletion of target proteins within human tumors in vivo using validated methodology will be a key to the application of this technology. Here, we present a flow cytometric-based approach to quantitatively determine protein levels in solid tumor material derived by fiber optic brushing (FOB) of non-small cell lung cancer (NSCLC) patients. Focusing upon the survivin protein, and its depletion by an antisense oligonucleotide (ASO) (LY2181308), we show that we can robustly identify a subpopulation of survivin positive tumor cells in FOB samples, and, moreover, detect survivin depletion in tumor samples from a patient treated with LY2181308. Survivin depletion appears to be a result of treatment with this ASO, because a tumor treated with conventional cytotoxic chemotherapy did not exhibit a decreased percentage of survivin positive cells. Our approach is likely to be broadly applicable to, and useful for, the quantification of protein levels in tumor samples obtained as part of clinical trials and studies, facilitating the proof-of-principle testing of novel targeted therapies.

DNA damage in cichlids from an oil production facility in Guatemala

This study focused on several wetlands in Laguna del Tigre National Park (Guatemala) as part of Conservation International's Rapid Assessment Program. Sediment and water samples were collected from a laguna near Xan field, Guatemala's largest oil facility, and three other sites for determination of levels of polycyclic aromatic hydrocarbons (PAHs). Cichlid fish (Thorichthys meeki and Vieja synspila) were collected for determination of DNA strand breakage (by gel electrophoresis), chromosomal breakage (flow cytometry), and fin erosion. For T. meeki from Xan field, chromosomal breakage and strand breakage was greater than in at least two of the three reference sites. For V. synspila, chromosomal breakage and strand breakage were greater in Xan than one of the two reference sites. Fin erosion was observed only at the Xan laguna. Genetic biomarker effects and fin erosion, along with patterns of aqueous PAH concentrations, indicate that fish are affected by anthropogenic contaminants. PAHs were elevated at some reference sites, but environmental forensic analysis suggested a pyrogenic or diagenic origin. It is possible that oil field brines injected into the ground water caused fin erosion and genotoxicity in fish at Xan field, and it is also possible that pyrogenic PAHs influence levels of DNA damage in reference sites. These analyses represent one of the first efforts to examine genotoxicity in native Mesoamerican cichlids.

Involvement of the nuclear proteasome activator PA28γ in the cellular response to DNA double-strand breaks

The DNA damage response (DDR) is a complex signaling network that leads to damage repair while modulating numerous cellular processes. DNA double-strand breaks (DSBs), a highly cytotoxic DNA lesion, activate this system most vigorously. The DSB response network is orchestrated by the ATM protein kinase, which phosphorylates key players in its various branches. Proteasome-mediated protein degradation plays an important role in the proteome dynamics following DNA damage induction. Here, we identify the nuclear proteasome activator PA28γ (REGγ; PSME3) as a novel DDR player. PA28γ depletion leads to cellular radiomimetic sensitivity and a marked delay in DSB repair. Specifically, PA28γ deficiency abrogates the balance between the two major DSB repair pathways--nonhomologous end-joining and homologous recombination repair. Furthermore, PA28γ is found to be an ATM target, being recruited to the DNA damage sites and required for rapid accumulation of proteasomes at these sites. Our data reveal a novel ATM-PA28γ-proteasome axis of the DDR that is required for timely coordination of DSB repair.

Ganoderma lucidum total triterpenes prevent radiation-induced DNA damage and apoptosis in splenic lymphocytes in vitro

The development of radioprotective agents has been the subject of intense research, especially in the field of radiotherapy. In this study, we examined the radioprotective activity of the total triterpenes isolated from Ganoderma lucidum (Fr.) P. Karst in mouse splenic lymphocytes in vitro. Using the MTT assay, Ganoderma triterpenes were found to have no effect on cell viability, indicating that they are non-toxic to splenic lymphocytes. The effect of the total triterpenes on DNA damage and apoptosis induced by radiation was analyzed using the comet assay, DNA ladder assay and flow cytometric analysis. Total triterpenes were found to be highly effective in preventing DNA laddering, even at low concentrations (25μg/ml). The comet assay demonstrated that the G. triterpenes effectively prevented DNA damage, and flow cytometry revealed a reduction in apoptotic cells. The effect of the total triterpenes on intracellular reactive oxygen species (ROS) level and endogenous antioxidant enzyme activity in splenic lymphocytes were determined to elucidate possible radioprotective mechanisms. Total triterpenes successfully reduced the formation of intracellular ROS and enhanced endogenous antioxidant enzyme activity in splenic lymphocytes following irradiation. Thus, these findings indicate that the total triterpenes isolated from G. lucidum have a remarkable ability to protect normal cells from radiation-induced damage, which suggests therapeutic potential.

ROS implication in a new antitumor strategy based on non-thermal plasma

Non-thermal plasma (NTP) is generated by ionizing neutral gas molecules/atoms leading to a highly reactive gas at ambient temperature containing excited molecules, reactive species and generating transient electric fields. Given its potential to interact with tissue or cells without a significant temperature increase, NTP appears as a promising approach for the treatment of various diseases including cancer. The aim of our study was to evaluate the interest of NTP both in vitro and in vivo. To this end, we evaluated the antitumor activity of NTP in vitro on two human cancer cell lines (glioblastoma U87MG and colorectal carcinoma HCT-116). Our data showed that NTP generated a large amount of reactive oxygen species (ROS), leading to the formation of DNA damages. This resulted in a multiphase cell cycle arrest and a subsequent apoptosis induction. In addition, in vivo experiments on U87MG bearing mice showed that NTP induced a reduction of bioluminescence and tumor volume as compared to nontreated mice. An induction of apoptosis was also observed together with an accumulation of cells in S phase of the cell cycle suggesting an arrest of tumor proliferation. In conclusion, we demonstrated here that the potential of NTP to generate ROS renders this strategy particularly promising in the context of tumor treatment.

Proliferation of germ cells and somatic cells in first trimester human embryonic gonads as indicated by S and S+G2+M phase fractions

OBJECTIVES

The number of germ cells and somatic cells in human embryonic and foetal gonads has previously been estimated by stereological methods, which are time- and labour-consuming with little information concerning cell proliferation. Here, we studied whether flow cytometry could be applied as an easier method, also enabling estimation of the fraction of cells in S or S+G(2)+M (SG(2) M) cell-cycle phases as indicators of cell proliferation.

METHODS

Cell suspensions from 35 human embryonic gonads at days 37 to 68 post-conception (pc) were immunomagnetically sorted into C-KIT positive (germ) cells and negative (somatic) cells. They were stained for DNA content and analysed by flow cytometry. S and SG(2) M fractions could be measured for 13 of the female and 20 of the male gonads. The number of cells was estimated using fluorescent reference beads.

RESULTS

During the period from 37 to 68 days pc, female germ and somatic cells had a stable S and SG(2) M fractions indicating steady growth of both subpopulations, whereas they decreased in both male germ and somatic cells. The number of germ and somatic cells estimated by flow cytometry was significantly lower than in stereological estimates, suggesting loss of cells during preparation.

CONCLUSIONS

Cell proliferation as indicated by S and SG(2) M fractions could be estimated specifically for primordial germ and somatic cells. Estimation of total number of germ and somatic cells was not feasible.

Statistical issues in subpopulation analysis of high content imaging data

High content imaging (HCI) is an increasingly important method for elucidating changes in cellular biology. The combination of validated immuno-fluorescent assays, availability of automated microscopy, and advances in image analysis software has led to increased exploitation of this technology in a variety of settings ranging from cellular signaling pathways to drug discovery. Recent advances in HCI have made the collection of multi-parametric datasets from high-throughput screening routine, but analysis of these data remains a challenge. The few existing analytical tools used to analyze HCI data, usually provided by HCI platform vendors, require extensive operator interaction and, more importantly, lack statistical power. This results in serious under-utilization of the information available from this powerful technology. As HCI applications become increasingly complex, measurements to estimate the composition of the cell population and thus the underlying data structure also becomes more complicated, and the analysis to facilitate the understanding of the biological system will rely heavily on analytical expertise that requires advanced statistical training. The aim of this article is to review the major statistical issues in HCI data analysis, with a focus on quantitative analysis of cell subpopulations.

Overview of flow cytometry and fluorescent probes for flow cytometry

This chapter provides an introduction to the use of fluorescent probes in flow cytometry. Sample preparation for the use of surface labeling with antibodies as well as for the use of nucleic acid probes is discussed. The utility of cell sorting is also discussed.

The foamy virus genome remains unintegrated in the nuclei of G1/S phase-arrested cells, and integrase is critical for preintegration complex transport into the nucleus

Foamy viruses are a member of the spumavirus subfamily of retroviruses with unique mechanisms of virus replication. Foamy virus replication is cell cycle dependent; however, the genome is found in the nuclei of cells arrested in the G(1)/S phase. Despite the presence of genome in the nuclei of growth-arrested cells, there is no viral gene expression, thus explaining its dependency on cell cycle. This report shows that the foamy virus genome remains unintegrated in G(1)/S phase-arrested cells. The foamy virus genome is detected by confocal microscopy in the nuclei of both dividing and growth-arrested cells. Alu PCR revealed foamy virus-specific DNA amplification from genomic DNA isolated in cycling cells at 24 h postinfection. In arrested cells no foamy virus DNA band was detected in cells harvested at 1 or 7 days after infection, and a very faint band that is significantly less than DNA amplified from cycling cells was observed at day 15. After these cells were arrested at the G(1)/S phase for 1, 7, or 15 days they were allowed to cycle, at which time foamy virus-specific DNA amplification was readily observed. Taken together, these results suggest that the foamy virus genome persists in nondividing cells without integrating. We have also established evidence for the first time that the foamy virus genome and Gag translocation into the nucleus are dependent on integrase in cycling cells, implicating the role of integrase in transport of the preintegration complex into the nucleus. Furthermore, despite the presence of a nuclear localization signal sequence in Gag, we observed no foamy virus Gag importation into the nucleus in the absence of integrase.

Wildlife toxicology: biomarkers of genotoxic exposures at a hazardous waste site

A large number of hazardous waste sites in the United States have undergone the initial stages of remediation or containment. At many of the remaining sites, the potential for exposure to ecological receptors is a primary concern. This manuscript reports on studies to investigate the impact on ecological receptors exposed to complex mixtures at a former creosote facility. Currently there are isolated areas on-site that were not addressed in the initial removal action that appear to be releasing polycyclic aromatic hydrocarbons (PAHs) to the surrounding environment. The U.S. EPA collected environmental samples and performed ex situ sediment bioassays to measure chronic toxicity; whereas, this study describes an in situ study to measure biomarkers of effect in two ecological receptors. Mosquitofish (Gambusia affinis) and cricket frogs (Acris crepitans) were collected from a small intermittent creek adjacent to the site, and reference stations. A weight-of-evidence ecological risk assessment was completed for the amphibian and fish communities. The ecological risk assessment was developed using analysis of media chemistry, body burden of specific PAHs, bioassay results, community surveys, and cellular genome size variation as a biomarker of genotoxicity. Flow cytometric estimates of chromosomal damage were significantly elevated for both mosquitofish and cricket frogs inhabiting the contaminated site, relative to at least one reference site. Surface water screening values for fish and amphibians exceeded screening values for PAHs by more than one order of magnitude in the on-site creek, and sediment PAH concentrations were extremely high (up to 1,549 microg/dry g). Tissue concentrations of PAHs were below screening values. Media chemistry, bioassay and genotoxicity data all support the same conclusion that on-site PAHs continue to impact aquatic receptors. The genotoxicity findings are consistent with and contribute to results of the weight-of-evidence ecological risk assessment. The results support continuing efforts to incorporate biomarkers as valuable lines of evidence within ecological risk assessment.

Antenatal detection of mosaic trisomy 9 by ultrasound: a case report and literature review

This paper presents a fetus with mosaic trisomy 9 diagnosed by chorionic villus sampling and confirmed by cordocentesis, and compares this case with published cases in order better to define the ultrasound markers confined to trisomy 9 syndrome. Detailed fetal ultrasound examination was carried out, revealing shortened femur, placental cysts and oligohydramnios. All published trisomy 9 cases with abnormal ultrasound findings were extracted from the MEDLINE database in the period from 1973 to 2002. We found 12 non-mosaic and 13 mosaic cases, including our case. The most frequent ultrasound abnormalities included characteristic cardiac, skeletal, craniofacial and central nervous system malformations. Intrauterine growth restriction and single umbilical artery were prevalent non-specific findings in both non-mosaic and mosaic groups. Parental chromosomal variations, as in our case, were not uncommon findings. When a fetus shows structural anomalies suggesting the presence of trisomy 9, karyotyping should be performed on both chorionic villi or amniocytes and fetal blood lymphocytes to enable a correct diagnosis to be made.

Heterogeneity of DNA content in laryngeal squamous cell carcinoma in relation to histopathological variables

CONCLUSION

Multivariate analysis showed age, lymph node status, proliferative index in transformation border, and DNA index in the center of laryngeal squamous cell carcinoma to be significant predictors for survival. By accessing distinctive areas of the tumor we were able to reduce the impact of intratumoral heterogeneity on prognostic factors.

OBJECTIVES

Laryngeal carcinomas are characterized by considerable histological variation within the tumor. The possible effects of this morphological heterogeneity on the estimation of tumor DNA content were investigated.

MATERIALS AND METHODS

We analyzed 92 cases of archived, paraffin-embedded laryngeal carcinoma. For each tumor, three different regions, defined microscopically (center of tumor, transformation border, invasive border), were analyzed. DNA content was measured by flow cytometry. Three parameters were evaluated: DNA ploidy, DNA index, and proliferative index.

RESULTS

DNA ploidy, DNA index, and proliferative index were higher in the tumor center than in the respective borders. Intratumoral differences in DNA ploidy were observed in 56 tumors (60.8%); DNA index heterogeneity was observed in 57.6% cases. Proliferative index varied greatly in morphologically different parts of the same carcinoma. DNA ploidy and DNA index of the transformation border correlated with tumor size and lymph node status. Proliferative index of the tumor center and of transformation border correlated with lymph node status, tumor size, and histological grade.

Establishing and maintaining system linearity

A flow cytometer system transforms a received optical signal into an electrical signal whose amplitude ideally is directly proportional to the optical signal but in practice is at least related in a linear fashion. Establishment and maintenance of system linearity are prerequisites to accurate quantitative measurements. The many potential sources of offsets and nonlinearity are found in all parts of the detection, amplification, and data acquisition systems of a flow instrument. This unit aims to help investigators evaluate performance of the hardware in flow cytometer detection systems.

Increased cellular hypoxia and reduced proliferation of both normal and leukaemic cells during progression of acute myeloid leukaemia in rats

The microenvironmental changes in the bone marrow, spleen and liver during progression of the transplantable promyelocytic leukaemia in the Brown Norwegian rat (BNML) have been studied. We used flow cytometry to estimate cellular hypoxia and proliferation based on in vivo pulse-labelling with a mixture of 2-nitroimidazole linked to theophylline (NITP) and bromodeoxyuridine (BrdUrd). The leukaemic cells were identified with the RM124 antibody. In rats inoculated with leukaemic cells the fraction of RM124+ cells was significantly increased from day 20 onwards in the spleen and from day 27 in the bone marrow and liver, reaching a level of 65-87% in these organs at day 32. At day 32, the NITP+ fraction of RM124+ cells had increased significantly in the bone marrow and spleen to 88% and 90%, respectively. The corresponding fractions of NITP+ normal cells reached 63% and 65%, respectively. From day 13 to day 32, the DNA-synthesizing (BrdUrd+) fraction of RM124+ cells in the bone marrow decreased significantly from 52% to 25%, and of normal cells from about 20% to 6%. In the bone marrow and spleen at day 27 and 32, the S-phase and G2/M-phase fractions according to DNA content were higher for the NITP+ than for the NITP- cells. This could partly be explained by an impaired cell cycle progression due to hypoxia. Nevertheless, we found indications of leukaemic cells that were simultaneously labelled with NITP and BrdUrd, in the bone marrow and spleen. These latter findings suggest that in contrast to normal cells some of the leukaemic cells can proliferate even during hypoxia, and this subpopulation may consequently renew and expand the leukaemic cell load.

DNA content measurement for DNA ploidy and cell cycle analysis

This unit presents the most common methods of DNA content analysis. The techniques differ primarily in the mode of cell permeabilization (detergents versus prefixation with alcohol) and composition of the stain solution. Protocols are given for analysis of fixed cells, tissue samples, live cells (for subsequent sorting and culture), archival paraffin-embedded tissue, and apoptotic cells.

Simultaneous analysis of cell surface antigens and DNA content by flow cytometry

Cells obtained from the blood or bone marrow of patients with haematological malignancies can both be stained with fluorescent labelled monoclonal antibodies to determine an immunophenotype and permeabilized with 30% ethanol then stained with propidium iodide for simultaneous DNA analysis. In the technique described here, no evidence of selective depletion of the malignant cell population was demonstrated and decreases in the mean fluorescence intensity of the surface markers were insufficient to affect the sensitivity of flow cytometric analysis. The combined method is simple and robust enough to allow incorporation of DNA analysis into routine immunophenotyping of leukaemia and lymphoma cells.

Statins stimulate in vitro membrane FasL expression and lymphocyte apoptosis through RhoA/ROCK pathway in murine melanoma cells

The capacity of FasL molecules expressed on melanoma cells to induce lymphocyte apoptosis contributes to either antitumor immune response or escape depending on their expression level. Little is known, however, about the mechanisms regulating FasL protein expression. Using the murine B16F10 melanoma model weakly positive for FasL, we demonstrated that in vitro treatment with statins, inhibitors of 3-hydroxy-3-methylgutaryl CoA reductase, enhances membrane FasL expression. C3 exotoxin and the geranylgeranyl transferase I inhibitor GGTI-298, but not the farnesyl transferase inhibitor FTI-277, mimic this effect. The capacity of GGTI-298 and C3 exotoxin to inhibit RhoA activity prompted us to investigate the implication of RhoA in FasL expression. Inhibition of RhoA expression by small interfering RNA (siRNA) increased membrane FasL expression, whereas overexpression of constitutively active RhoA following transfection of RhoAV14 plasmid decreased it. Moreover, the inhibition of a RhoA downstream effector p160ROCK also induced this FasL overexpression. We conclude that the RhoA/ROCK pathway negatively regulates membrane FasL expression in these melanoma cells. Furthermore, we have shown that B16F10 cells, through the RhoA/ROCK pathway, promote in vitro apoptosis of Fas-sensitive A20 lymphoma cells. Our results suggest that RhoA/ROCK inhibition could be an interesting target to control FasL expression and lymphocyte apoptosis induced by melanoma cells.

Modification of Kolmogorov-Smirnov test for DNA content data analysis through distribution alignment

The Kolmogorov-Smirnov (K-S) test is a statistical method often used for comparing two distributions. In high-throughput screening (HTS) studies, such distributions usually arise from the phenotype of independent cell populations. However, the K-S test has been criticized for being overly sensitive in applications, and it often detects a statistically significant difference that is not biologically meaningful. One major reason is that there is a common phenomenon in HTS studies that systematic drifting exists among the distributions due to reasons such as instrument variation, plate edge effect, accidental difference in sample handling, etc. In particular, in high-content cellular imaging experiments, the location shift could be dramatic since some compounds themselves are fluorescent. This oversensitivity of the K-S test is particularly overpowered in cellular assays where the sample sizes are very big (usually several thousands). In this paper, a modified K-S test is proposed to deal with the nonspecific location-shift problem in HTS studies. Specifically, we propose that the distributions are "normalized" by density curve alignment before the K-S test is conducted. In applications to simulation data and real experimental data, the results show that the proposed method has improved specificity.

Base excision repair of ionizing radiation-induced DNA damage in G1 and G2 cell cycle phases

BACKGROUND

Major genomic surveillance mechanisms regulated in response to DNA damage exist at the G1/S and G2/M checkpoints. It is presumed that these delays provide time for the repair of damaged DNA. Cells have developed multiple DNA repair pathways to protect themselves from different types of DNA damage. Oxidative DNA damage is processed by the base excision repair (BER) pathway. Little is known about the BER of ionizing radiation-induced DNA damage and putative heterogeneity of BER in the cell cycle context. We measured the activities of three BER enzymes throughout the cell cycle to investigate the cell cycle-specific repair of ionizing radiation-induced DNA damage. We further examined BER activities in G2 arrested human cells after exposure to ionizing radiation.

RESULTS

Using an in vitro incision assay involving radiolabeled oligonucleotides with specific DNA lesions, we examined the activities of several BER enzymes in the whole cell extracts prepared from synchronized human HeLa cells irradiated in G1 and G2 phase of the cell cycle. The activities of human endonuclease III (hNTH1), a glycosylase/lyase that removes several damaged bases from DNA including dihydrouracil (DHU), 8-oxoguanine-DNA glycosylase (hOGG1) that recognizes 7,8-dihydro-8-oxo-2'-deoxyguanosine (8-oxoG) lesion and apurinic/apyrimidinic endonuclease (hAPE1) that acts on abasic sites including synthetic analog furan were examined.

CONCLUSION

Overall the repair activities of hNTH1 and hAPE1 were higher in the G1 compared to G2 phase of the cell cycle. The percent cleavages of oligonucleotide substrate with furan were greater than substrate with DHU in both G1 and G2 phases. The irradiation of cells enhanced the cleavage of substrates with furan and DHU only in G1 phase. The activity of hOGG1 was much lower and did not vary within the cell cycle. These results demonstrate the cell cycle phase dependence on the BER of ionizing radiation-induced DNA damage. Interestingly no evidence of enhanced BER activities was found in irradiated cells arrested in G2 phase.

Mixture-model classification in DNA content analysis

DNA abundance provides important information about cell physiology and proliferation activity. In a typical in vitro cellular assay, the distribution of the DNA content within a sample is comprised of cell debris, G0/G1-, S-, and G2/M-phase cells. In some circumstances, there may be a collection of cells that contain more than two copies of DNA. The primary focus of DNA content analysis is to deconvolute the overlapping mixtures of the cellular components, and subsequently to investigate whether a given treatment has perturbed the mixing proportions of the sample components. We propose a restricted mixture model that is parameterized to incorporate the available biological information. A likelihood ratio (LR) test is developed to test for changes in the mixing proportions between two cell populations. The proposed mixture model is applied to both simulated and real experimental data. The model fitting is compared with unrestricted models; the statistical inference on proportion change is compared between the proposed LR test and the Kolmogorov-Smirnov test, which is frequently used to test for differences in DNA content distribution. The proposed mixture model outperforms the existing approaches in the estimation of the mixing proportions and gives biologically interpretable results; the proposed LR test demonstrates improved sensitivity and specificity for detecting changes in the mixing proportions.

Synthesis and characterization of a metal complex containing naringin and Cu, and its antioxidant, antimicrobial, antiinflammatory and tumor cell cytotoxicity

The antioxidant activity of flavonoids is believed to increase when they are coordinated with transition metal ions. However, the literature on this subject is contradictory and the outcome seems to largely depend on the experimental conditions. In order to understand the contribution of the metal coordination and the type of interaction between a flavonoid and the metal ion, in this study a new metal complex of Cu (II) with naringin was synthesized and characterized by FT-IR, UV-VIS, mass spectrometry (ESI-MS/MS), elemental analysis and 1H-NMR. The results of these analyses indicate that the complex has a Cu (II) ion coordinated via positions 4 and 5 of the flavonoid. The antioxidant, anti-inflammatory and antimicrobial activities of this complex were studied and compared with the activity of free naringin. The Naringin-Cu (II) complex 1 showed higher antioxidant, anti-inflammatory and tumor cell cytotoxicity activities than free naringin without reducing cell viability.

Synthesis and characterization of a metal complex containing naringin and Cu, and its antioxidant, antimicrobial, antiinflammatory and tumor cell cytotoxicity

The antioxidant activity of flavonoids is believed to increase when they are coordinated with transition metal ions. However, the literature on this subject is contradictory and the outcome seems to largely depend on the experimental conditions. In order to understand the contribution of the metal coordination and the type of interaction between a flavonoid and the metal ion, in this study a new metal complex of Cu (II) with naringin was synthesized and characterized by FT-IR, UV-VIS, mass spectrometry (ESI-MS/MS), elemental analysis and 1H-NMR. The results of these analyses indicate that the complex has a Cu (II) ion coordinated via positions 4 and 5 of the flavonoid. The antioxidant, anti-inflammatory and antimicrobial activities of this complex were studied and compared with the activity of free naringin. The Naringin-Cu (II) complex 1 showed higher antioxidant, anti-inflammatory and tumor cell cytotoxicity activities than free naringin without reducing cell viability.

Cell cycle effect on the activity of deoxynucleoside analogue metabolising enzymes

Deoxynucleoside analogues (dNAs) are cytotoxic towards both replicating and indolent malignancies. The impact of fluctuations in the metabolism of dNAs in relation to cell cycle could have strong implications regarding the activity of dNAs. Deoxycytidine kinase (dCK) and deoxyguanosine kinase (dGK) are important enzymes for phosphorylation/activation of dNAs. These drugs can be dephosphorylated/deactivated by 5'-nucleotidases (5'-NTs) and elevated activities of 5'-NTs and decreased dCK and/or dGK activities represent resistance mechanisms towards dNAs. The activities of dCK, dGK, and three 5'-NTs were investigated in four human leukemic cell lines in relationship to cell cycle progression and cytotoxicity of dNAs. Synchronization of cell cultures to arrest in G0/G1 by serum-deprivation was performed followed by serum-supplementation for cell cycle progression. The activities of dCK and dGK increased up to 3-fold in CEM, HL60, and MOLT-4 cells as they started to proliferate, while the activity of cytosolic nucleotidase I was reduced in proliferating cells. CEM, HL60, and MOLT-4 cells were also more sensitive to cladribine, cytarabine, 9-beta-D-arabinofuranosylguanine and clofarabine than K562 cells which demonstrated lower levels and less alteration of these enzymes and were least susceptible to the cytotoxic effects of most dNAs. The results suggest that, in the cell lines studied, the proliferation process is associated with a general shift in the direction of activation of dNAs by inducing activities of dCK/dGK and reducing the activity of cN-I which is favourable for the cytotoxic effects of cladribine, cytarabine and, 9-beta-D-arabinofuranosylguanine. These results emphasize the importance of cellular proliferation and dNA metabolism by both phosphorylation and dephosphorylation for susceptibility to dNAs. It underscores the need to understand the mechanisms of action and resistance to dNAs in order to increase efficacy of dNAs treatment by new rational.

Inhibition of phosphatidylinositol-3-OH kinase/Akt signaling impairs DNA repair in glioblastoma cells following ionizing radiation

Radiation therapy is a mainstay in the treatment of glioblastomas, but these tumors are often associated with radioresistance. Activation of the phosphatidylinositol-3-OH kinase (PI3K)/Akt pathway, which occurs frequently in glioblastomas due to inactivation of the tumor suppressor phosphatase and tensin homologue (PTEN), correlates with radioresistance. To directly test the link between Akt activation and radioresistance, we utilized PTEN-deficient U251 glioblastoma cells engineered to inducibly restore PTEN upon exposure to doxycycline. These cells showed high basal levels of Akt activation (i.e. high levels of phospho-Akt), but induction of PTEN led to substantially decreased phospho-Akt and was associated with radiosensitization. To investigate whether the PTEN-induced radiosensitization was attributable to impaired sensing versus repair of DNA damage, we assessed levels of gamma-H2AX after ionizing radiation in U251 cells induced for PTEN. Initial post-radiation levels of gamma-H2AX foci were not decreased in PTEN-induced cells; however, the resolution of these foci was significantly delayed. In contrast to these results, induction of phosphatase-dead PTEN showed no appreciable effect. Finally, exposure of cells to the PI3K inhibitor LY294002 did not decrease the occurrence of gamma-H2AX foci after irradiation but did markedly delay their resolution. These results together support a direct link between Akt activation, repair of DNA damage, and radioresistance in glioblastoma. Targeting the PI3K/Akt pathway may modulate DNA repair to improve the efficacy of radiation therapy.

Q-FIHC: quantification of fluorescence immunohistochemistry to analyse p63 isoforms and cell cycle phases in human limbal stem cells

Fluorescence microscopy has long been used for qualitative characterization of various parameters such as subcellular distribution of proteins, lipids, nucleic acids, and ions. However, quantification of these parameters is complicated by a variety of optical, biological, and physical factors. In the last decade, the progress achieved with powerful softwares and digital image processing systems has facilitated the development of fluorescence immunohistochemistry (FIHC) into a widely used quantitative assay (quantitative-FIHC or Q-FIHC). We describe here a rapid and sensitive Q-FIHC assay based on the use of a laser scanning confocal microscope and advanced image analysis softwares (Zeiss semi automatic LSM 510 and fully automatic Axiovision 4.4) for the detection and quantification of fluorescent intensity in human corneal tissues and cells obtained from small clinical samples. We have used this methodology to characterize and quantify the gene expression profile of p63 and its DeltaNalpha isoform, specific markers of human limbal stem cells. The validity of this method was evaluated through comparative studies with conventional approaches suggesting no significant differences and providing an alternative technique to traditional methods. Since Q-FIHC requires at least 20-fold less cells than traditional techniques, we have adopted it as the main quality control for our limbal cultures destined to clinical application.

TIMP-1 gene deficiency increases tumour cell sensitivity to chemotherapy-induced apoptosis

Tissue inhibitor of metalloproteinases-1 (TIMP-1) is one of four inhibitors of the matrix metalloproteinases, which are capable of degrading most components of the extracellular matrix. However, in recent years, TIMP-1 has been recognised as a multifunctional protein, playing a complex role in cancer. In this regard, several studies have demonstrated an antiapoptotic effect of TIMP-1 in a number of different cell types. Since chemotherapy works by inducing apoptosis in cancer cells, we raised the hypothesis that TIMP-1 promotes resistance against chemotherapeutic drugs. In order to investigate this hypothesis, we have established TIMP-1 gene-deficient and TIMP-1 wild-type fibrosarcoma cells from mouse lung tissue. We have characterised these cells with regard to TIMP-1 genotype, TIMP-1 expression, malignant transformation and sensitivity to chemotherapy-induced apoptosis. We show that TIMP-1 gene deficiency increases the response to chemotherapy considerably, confirming that TIMP-1 protects the cells from apoptosis. This is to our knowledge the first study investigating TIMP-1 and chemotherapy-induced apoptosis employing a powerful model system comprising TIMP-1 gene-deficient cells and their genetically identical wild-type controls. For future studies, this cell system can be used to uncover the mechanisms and signalling pathways involved in the TIMP-1-mediated inhibition of apoptosis as well as to investigate the possibility of using TIMP-1 inhibitors to optimise the effect of conventional chemotherapy.

The cytogenetic relationship between primary and recurrent meningiomas points to the need for new treatment strategies in cases at high risk of relapse

PURPOSE

Recurrence is the major factor influencing the clinical outcome of meningioma patients although the exact relationship between primary and recurrent tumors still needs to be clarified. The aim of the present study is to analyze the cytogenetic relationship between primary and subsequent recurrent meningiomas developed within the same individual.

EXPERIMENTAL DESIGN

Multicolor interphase fluorescence in situ hybridization was done for the identification of numerical abnormalities of 12 chromosomes in single-cell suspensions from 59 tumor samples corresponding to 25 recurrent meningioma patients. In 47 of these tumors, the distribution of different tumor cell clones was also analyzed in paraffin-embedded tissue sections. In parallel, 132 nonrecurrent cases were also studied.

RESULTS

Most recurrent meningiomas showed complex cytogenetic aberrations associated with two or more tumor cell clones in the first tumor analyzed. Interestingly, in most individuals (74%), exactly the same tumor cell clones identified in the initial lesion were also detected in the subsequent recurrent tumor samples. In the recurrent tumor samples of the remaining cases (26%), we observed tumor cell clones related to those detected in the initial lesion but which had acquired one or more additional chromosome aberrations associated with either the emergence of new clones with more complex karyotypes or the disappearance of the most representative clones from the primary lesions. Multivariate analysis of prognostic factors showed that the Maillo et al. prognostic score, based on age of patient, tumor grade, and monosomy 14, together with tumor size was the best combination of independent variables for predicting tumor recurrence at diagnosis.

CONCLUSION

Overall, our results indicate that the development of recurrent meningiomas after complete tumor resection is usually due to regrowth of the primary tumor and rarely to the emergence of an unrelated meningioma, underlining the need for alternative treatment strategies in cases at high risk of relapse, particularly those with a high Maillo et al. prognostic score and larger tumors.

Flow cytometric DNA index, G-band karyotyping, and comparative genomic hybridization in detection of high hyperdiploidy in childhood acute lymphoblastic leukemia

High hyperdiploid acute lymphoblastic leukemia in children is related to a good outcome. Because these patients may be stratified to a low-intensity treatment, we have investigated the sensitivity of flow cytometry (FCM), G-band karyotyping (GBK), and high-resolution comparative genomic hybridization (HR-CGH) in detecting high hyperdiploid leukemic clones. Twenty-six girls and 34 boys with acute lymphoblastic leukemia diagnosed in 1998 to 1999 were analyzed by FCM, GBK, and HR-CGH. The correlations between DNA indices obtained by FCM, GBK, and HR-CGH were significant (rs=0.61 to 0.77; P<0.001 for all comparisons). However, in 4 of 18 patients, high hyperdiploidy was overlooked by GBK or HR-CGH, and even when FCM was applied, 2 of 18 patients with high hyperdiploidy by GBK and/or HR-CGH were classified as nonhigh hyperdiploid. If high hyperdiploid subclones were included, FCM could detect all high hyperdiploid patients found by either GBK or HR-CGH, but would then in addition classify 15% to 20% of the remaining patients as high hyperdiploid. Thus, both GBK and HR-CGH overlook patients with high hyperdiploidy, and FCM only detects all high hyperdiploid patients if small high hyperdiploid clones are included. In addition, FCM detects patients with high hyperdiploid subclones, not detected by either GBK or HR-CGH, and the challenge remains to determine the prognosis of patients with such high hyperdiploid subclones.