Prognostic significance of an apoptotic index and apoptosis/proliferation ratio for patients with high-grade astrocytomas

Clearance of apoptotic cells by neutrophils in inflammation and cancer

When a cell dies of apoptosis, it is eliminated either by neighbouring cells or by attracted professional phagocytes. Although it was generally believed that neutrophils also have the ability to perform efferocytosis, their contribution to the clearance of apoptotic cells was considered less important compared with macrophages. Therefore, this ability of neutrophils remained unexplored for a long time. Over the past decade, it has been shown that during inflammation, neutrophils contribute significantly to the clearance of apoptotic neutrophils that accumulate in large numbers at the site of tissue damage. This "neutrophil cannibalism" is accompanied by inhibition of pro-inflammatory activities of these cells, such as respiratory burst and formation of neutrophil extracellular traps (NETs). Furthermore, efferocytosing neutrophils secrete anti-inflammatory mediators and mitogens including hepatocyte growth factor (HGF), fibroblast growth factor 2 (FGF2), vascular endothelial growth factors (VEGF), and transforming growth factor beta (TGFβ). Thus, efferocytosis by neutrophils is involved in resolution of inflammation. Recent research indicates that it plays also a role in cancer. Many different solid tumours contain aggregates of dead tumour cells that have undergone spontaneous apoptosis. Their extent correlates with poor clinical outcome in most cancer types. These clusters of apoptotic tumour cells are strongly infiltrated by tumour-associated neutrophils (TANs) that acquired an anti-inflammatory and pro-resolving polarization state. This review summarizes the potential consequences discussed in the current literature. Although the picture of the role of efferocytosis by neutrophils in inflammation and cancer is becoming clearer, many questions are still unexplored.

Perivascular Stromal Cells Instruct Glioblastoma Invasion, Proliferation, and Therapeutic Response within an Engineered Brain Perivascular Niche Model

Glioblastoma (GBM) tumor cells are found in the perivascular niche microenvironment and are believed to associate closely with the brain microvasculature. However, it is largely unknown how the resident cells of the perivascular niche, such as endothelial cells, pericytes, and astrocytes, influence GBM tumor cell behavior and disease progression. A 3D in vitro model of the brain perivascular niche developed by encapsulating brain-derived endothelial cells, pericytes, and astrocytes in a gelatin hydrogel is described. It is shown that brain perivascular stromal cells, namely pericytes and astrocytes, contribute to vascular architecture and maturation. Cocultures of patient-derived GBM tumor cells with brain microvascular cells are used to identify a role for pericytes and astrocytes in establishing a perivascular niche environment that modulates GBM cell invasion, proliferation, and therapeutic response. Engineered models provide unique insight regarding the spatial patterning of GBM cell phenotypes in response to a multicellular model of the perivascular niche. Critically, it is shown that engineered perivascular models provide an important resource to evaluate mechanisms by which intercellular interactions modulate GBM tumor cell behavior, drug response, and provide a framework to consider patient-specific disease phenotypes.

Prognostic role of Ki-67 in glioblastomas excluding contribution from non-neoplastic cells

Survival of glioblastoma patients varies and prognostic markers are important in the clinical setting. With digital pathology and improved immunohistochemical multiplexing becoming a part of daily diagnostics, we investigated the prognostic value of the Ki-67 labelling index (LI) in glioblastomas more precisely than previously by excluding proliferation in non-tumor cells from the analysis. We investigated the Ki-67 LI in a well-annotated population-based glioblastoma patient cohort (178 IDH-wildtype, 3 IDH-mutated). Ki-67 was identified in full tumor sections with automated digital image analysis and the contribution from non-tumor cells was excluded using quantitative double-immunohistochemistry. For comparison of the Ki-67 LI between WHO grades (II-IV), 9 IDH-mutated diffuse astrocytomas and 9 IDH-mutated anaplastic astrocytomas were stained. Median Ki-67 LI increased with increasing WHO grade (median 2.7%, 6.4% and 27.5%). There was no difference in median Ki-67 LI between IDH-mutated and IDH-wildtype glioblastomas (p = 0.9) and Ki-67 LI was not associated with survival in glioblastomas in neither univariate (p = 0.9) nor multivariate analysis including MGMT promoter methylation status and excluding IDH-mutated glioblastomas (p = 0.2). Ki-67 may be of value in the differential diagnostic setting, but it must not be over-interpreted in the clinico-pathological context.

Proliferation to Apoptosis Tumor Cell Ratio as a Biomarker to Improve Clinical Management of Pre-Malignant and Symptomatic Plasma Cell Neoplasms

Proliferation and apoptosis of neoplastic cells are prognostic biomarkers in plasma cell neoplasms (PCNs). The prognostic capacity of proliferation to apoptosis ratio (Ratio-PA) in the era of immunomodulatory treatments is re-evaluated in 316 gammopathy of undetermined significance (MGUS), 57 smoldering multiple myeloma (SMM), and 266 multiple myeloma (MM) patients. Ratio-PA of 0.77 ± 0.12, 1.94 ± 0.52, and 11.2 ± 0.7 (p < 0.0001) were observed in MGUS, SMM, and MM patients. Ten-year overall survival (10y-OS) rates for patients with low/high Ratio-PA were 93.5%/77.3% p < 0.0001) for MGUS, 82.5%/64.7% (p < 0.05) for SMM, and 62.3%/47.0% (p < 0.05) for MM. For patients with low, intermediate, and high risk, 10y-OS for low/high Ratio-PA were 95.5%/72.9% (p < 0.0001), 74.2%/50.4% (p < 0.0001), and 35.3%/20.0% (p = 0.836), respectively. Ratio-PA was an independent prognostic factor for OS (HR = 2.119, p < 0.0001, Harrell-C-statistic = 0.7440 ± 0.0194) when co-analyzed with sex, age, and standard risk. In patients with Ratio-PA^high, only first-line therapy with VRd/VTd, but not PAD/VCD, coupled with ASCT was associated with high 10y-OS (82.7%). Tumor cell Ratio-PA estimated at diagnosis offers a prognostic biomarker that complements standard risk stratification and helps to guide the clinical management of pre-malignant and symptomatic PCNs. Every effort should be made to provide first-line therapies including VTd or VRd associated with ASCT to patients with Ratio-PA^high at higher risk of progression and death.

A Priori Activation of Apoptosis Pathways of Tumor (AAAPT) technology: Development of targeted apoptosis initiators for cancer treatment

Cancer cells develop tactics to circumvent the interventions by desensitizing themselves to interventions. Amongst many, the principle routes of desensitization include a) activation of survival pathways (e.g. NF-kB, PARP) and b) downregulation of cell death pathways (e.g. CD95/CD95L). As a result, it requires high therapeutic dose to achieve tumor regression which, in turn damages normal cells through the collateral effects. Methods are needed to sensitize the low and non-responsive resistant tumor cells including cancer stem cells (CSCs) in order to evoke a better response from the current treatments. Current treatments including chemotherapy can induce cell death only in bulk cancer cells sparing CSCs and cancer resistant cells (CRCs) which are shown to be responsible for high recurrence of disease and low patient survival. Here, we report several novel tumor targeted sensitizers derived from the natural Vitamin E analogue (AMP-001-003). The drug design is based on a novel concept "A priori activation of apoptosis pathways of tumor technology (AAAPT) which is designed to activate specific cell death pathways and inhibit survival pathways simultaneously and selectively in cancer cells sparing normal cells. Our results indicate that AMP-001-003 sensitize various types of cancer cells including MDA-MB-231 (triple negative breast cancer), PC3 (prostate cancer) and A543 (lung cancer) cells resulting in reducing the IC-50 of doxorubicin in vitro when used as a combination. At higher doses, AMP-001 acts as an anti-tumor agent on its own. The synergy between AMP-001 and doxorubicin could pave a new pathway to use AAAPT leading molecules as neoadjuvant to chemotherapy to achieve better efficacy and reduced off-target toxicity compared to the current treatments.

Diffuse leptomeningeal glioneuronal tumor in a Chinese adult: a novel case report and review of literature

Diffuse leptomeningeal glioneuronal tumor (DLGNT) is a rare glioma tumor classified by the World Health Organization as a central nervous system tumor in 2016. DLGNT is most common in children and adolescents but is rare in adults. A 25-year-old male patient was admitted due to recurrent seizures. Head magnetic resonance imaging revealed lesions in the right temporal lobe, which were considered to be intracranial tumors with variable properties. The patient was admitted for surgical treatment. After admission, it was confirmed that seizures were associated with right temporal lobe lesions. Right temporal epileptogenic focus resection was performed by craniotomy. Immunohistochemistry revealed that tumor cells were reactive for oligodendrocyte transcription factor 2, synaptophysin, S100 proteins, and α-thalassemia mental retardation X-linked; and partially reactive for neuronal nuclei, glial fibrillary acidic protein, and nestin. The vascular wall was reactive for vimentin, CD34, CD31, and smooth muscle actin. Ki-67 was 4%. Molecular detection demonstrated 1p36 deletion, O⁶-methylguanine-DNA-methyltransferase methylation, and positive v-raf murine sarcoma viral oncogene homolog B mutation. DLGNT. The patient recovered well after surgery and received 54 Gy/27f radiotherapy without neurological dysfunction and seizures. In this study, onset age, tumor site, tumor increment coefficient, molecular detection, treatment methods, and prognosis of 54 patients were summarized from 19 studies. DLGNT patients are characterized by more singular tumor site, smaller volume, lower increment coefficient, and longer stable disease period. Patients with DLGNT may also have a longer stable condition in cases of molecular detection of 1p/19q deletion, or BRAF fusion.

Histopathologic quantification of viable tumor versus treatment effect in surgically resected recurrent glioblastoma

PURPOSE

The prognostic impact of the histopathologic features of recurrent glioblastoma surgical specimens is unknown. We sought to determine whether key histopathologic characteristics in glioblastoma tumors resected after chemoradiotherapy are associated with overall survival (OS).

METHODS

The following characteristics were quantified in recurrent glioblastoma specimens at our institution: extent of viable tumor (accounting for % of specimen comprised of tumor and tumor cellularity), mitoses per 10 high-power fields (0, 1-10, > 10), Ki-67 proliferative index (0-100%), hyalinization (0-6; none to extensive), rarefaction (0-6), hemosiderin (0-6), and % of specimen comprised of geographic necrosis (0-100%; converted to 0-6 scale). Variables associated with OS in univariate analysis, as well as age, eastern cooperative oncology group performance status (ECOG PS), extent of repeat resection, time from initial diagnosis to repeat surgery, and O⁶-methylguanine-DNA methyltransferase promoter methylation, were included in a multivariable Cox proportional hazards model.

RESULTS

37 specimens were assessed. In a multivariate model, high Ki-67 proliferative index was the only histopathologic characteristic associated with worse OS following repeat surgery for glioblastoma (hazard ratio (HR) 1.3, 95% CI 1.1-1.5, p = 0.003). Shorter time interval from initial diagnosis to repeat surgery (HR 1.11, 95% CI 1.02-1.21, p = 0.016) and ECOG PS ≥ 2 (HR 4.19, 95% CI 1.72-10.21, p = 0.002) were also independently associated with inferior OS.

CONCLUSION

In patients with glioblastoma undergoing repeat resection following chemoradiotherapy, high Ki-67 index in the recurrent specimen, short time to recurrence, and poor PS are independently associated with worse OS. Histopathologic quantification of viable tumor versus therapy-related changes has limited prognostic influence.

Nanoparticle design considerations for molecular imaging of apoptosis: Diagnostic, prognostic, and therapeutic value

The present review analyzes various approaches for the design and synthesis of different nanoparticles for imaging and therapy. Nanoparticles for computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET) and optical imaging are discussed. The influence of nanoparticle size, shape, surface charge, composition, surface functionalization, active targeting and other factors on imaging and therapeutic efficacy is analyzed. Cyto- and genotoxicity of nanoparticles are also discussed. Special attention in the review is paid to the imaging of apoptotic tissues and cells in different diseases.

Coating independent cytotoxicity of citrate- and PEG-coated silver nanoparticles on a human hepatoma cell line

The antibacterial potential of silver nanoparticles (AgNPs) resulted in their increasing incorporation into consumer, industrial and biomedical products. Therefore, human and environmental exposure to AgNPs (either as an engineered product or a contaminant) supports the emergent research on the features conferring them different toxicity profiles. In this study, 30nm AgNPs coated with citrate or poly(ethylene glycol) (PEG) were used to assess the influence of coating on the effects produced on a human hepatoma cell line (HepG2), namely in terms of viability, apoptosis, apoptotic related genes, cell cycle and cyclins gene expression. Both types of coated AgNPs decreased cell proliferation and viability with a similar toxicity profile. At the concentrations used (11 and 5μg/mL corresponding to IC50 and ~IC10 levels, respectively) the amount of cells undergoing apoptosis was not significant and the apoptotic related genes BCL2 (anti-apoptotic gene) and BAX (pro-apoptotic gene) were both downregulated. Moreover, both AgNPs affected HepG2 cell cycle progression at the higher concentration (11μg/mL) by increasing the percentage of cells in S (synthesis phase) and G2 (Gap 2 phase) phases. Considering the cell-cycle related genes, the expression of cyclin B1 and cyclin E1 genes were decreased. Thus, this work has shown that citrate- and PEG-coated AgNPs impact on HepG2 apoptotic gene expression, cell cycle dynamics and cyclin regulation in a similar way. More research is needed to determine the properties that confer AgNPs at lower toxicity, since their use has proved helpful in several industrial and biomedical contexts.

Glioblastoma Multiforme in Three Baboons (Papio spp.)

Glioblastoma multiforme is the most malignant astrocytic neoplasm and the most common brain neoplasm of humans. Spontaneous neoplasms of the brain are rare in nonhuman primates. This report describes three glioblastomas in adult captive-reared baboons. The animals exhibited a range of clinical signs, including depression, weight loss, weakness, and blindness. All three neoplasms were located in the cerebrum, with extension into the pons in one case. Histologically, the tumors were similar and were characterized by cellular pleomorphism, multinucleated cells, areas of necrosis, microvascular proliferation (glomeruloid bodies), and palisading of neoplastic cells around blood vessels and areas of necrosis. Two baboons exhibited gemistocytic differentiation, and in one baboon, the neoplastic cells were predominantly spindle shaped with a fascicular growth pattern. Immunohistochemical staining for glial fibrillary acidic protein, vimentin, and S-100 protein was positive, whereas immunostaining for synaptophysin and chromogranin A was negative. Positive staining for the cell proliferation marker Ki67 ranged from 8.2% to 13.9%. Terminal deoxynucleotidyl transferase mediated dVTPnick end labeling (TUNEL) staining ranged from 1.8% to 5.7%. These baboon glioblastomas share many features with those of humans.

The effect of silver nanoparticles (AgNPs) on proliferation and apoptosis of in ovo cultured glioblastoma multiforme (GBM) cells

Recently, it has been shown that silver nanoparticles (AgNPs) provide a unique approach to the treatment of tumors, especially those of neuroepithelial origin. Thus, the aim of this study was to evaluate the impact of AgNPs on proliferation and activation of the intrinsic apoptotic pathway of glioblastoma multiforme (GBM) cells cultured in an in ovo model. Human GBM cells, line U-87, were placed on chicken embryo chorioallantoic membrane. After 8 days, the tumors were divided into three groups: control (non-treated), treated with colloidal AgNPs (40 μg/ml), and placebo (tumors supplemented with vehicle only). At the end of the experiment, all tumors were isolated. Assessment of cell proliferation and cell apoptosis was estimated by histological, immunohistochemical, and Western blot analyses. The results show that AgNPs can influence GBM growth. AgNPs inhibit proliferation of GBM cells and seem to have proapoptotic properties. Although there were statistically significant differences between control and AgNP groups in the AI and the levels of active caspase 9 and active caspase 3, the level of these proteins in GBM cells treated with AgNPs seems to be on the border between the spontaneous apoptosis and the induced. Our results indicate that the antiproliferative properties of silver nanoparticles overwhelm proapoptotic ones. Further research focused on the cytotoxic effect of AgNPs on tumor and normal cells should be conducted.

The impact of TP53 and RAS mutations on cerebellar glioblastomas

Cerebellar glioblastoma (cGBM) is a rare, inadequately characterized disease, without detailed information on its molecular basis. This is the first report analyzing both TP53 and RAS alterations in cGBM. TP53 mutations were detected in more than half of the samples from our cohort, mainly in hotspot codons. There were no activating mutations in hotspot codons 12/13 and 61 of KRAS and HRAS genes in cGBM samples but we detected alterations in other parts of exons 2 and 3 of these genes, including premature induction of STOP codon. This mutation was present in 3 out of 5 patients. High incidence of RAS mutations, as well as significantly longer survival of cGBM patients compared to those with supratentorial GBM suggest that cGBM may have different mechanisms of occurrence. Our results suggest that inactivation of TP53 and RAS may play an important role in the progression of cerebellar GBM.

Chemosensitization of IκBα-overexpressing glioblastoma towards anti-cancer agents

Mode of action of 5-FU and curcumin nanoconjugates in U87-IκBα cells.

Cancer stem cells in solid tumors: is 'evading apoptosis' a hallmark of cancer?

Conventional wisdom has long held that once a cancer cell has developed it will inevitably progress to clinical disease. Updating this paradigm, it has more recently become apparent that the tumor interacts with its microenvironment and that some environmental bottlenecks, such as the angiogenic switch, must be overcome for the tumor to progress. In parallel, attraction has been drawn to the concept that there is a minority population of cells - the cancer stem cells - bestowed with the exclusive ability to self-renew and regenerate the tumor. With therapeutic targeting issues at stake, much attention has shifted to the identification of cancer stem cells, the thinking being that the remaining non-stem population, already fated to die, will play a negligible role in tumor development. In fact, the newly appreciated importance of intercellular interactions in cancer development also extends in a unique and unexpected way to interactions between the stem and non-stem compartments of the tumor. Here we discuss recent findings drawn from a hybrid mathematical-cellular automaton model that simulates growth of a heterogeneous solid tumor comprised of cancer stem cells and non-stem cancer cells. The model shows how the introduction of cell fate heterogeneity paradoxically influences the tumor growth dynamic in response to apoptosis, to reveal yet another bottleneck to tumor progression potentially exploitable for disease control.

Targeting apoptosis pathways in glioblastoma

The treatment of glioblastoma remains a major challenge for clinicians since these highly aggressive brain tumors are relatively resistant towards radio- and chemotherapy. The pathways that control apoptosis are altered in glioblastoma cells leading to resistance towards apoptotic stimuli in general. In this review we describe the alterations affecting the p53 pathway, the BCL-2 protein family, the inhibitor of apoptosis proteins and several growth factor pathways involved in the regulation of programmed cell death and define possible targets for new therapies within these apoptotic pathways in glioblastomas. Moreover, we review strategies to target death receptor pathways, most notably to render the glioblastoma cells more susceptible towards this approach without enhancing toxicity in general. Most of the strategies targeting apoptosis in glioblastomas presented here are in a pre-clinical stage of development, however, they all share the ultimative goal to improve the outcome for glioblastoma patients.

Comparison of ACINUS, caspase-3, and TUNEL as apoptotic markers in determination of tumor growth rates of clinically localized prostate cancer using image analysis

BACKGROUND

The balance between apoptotic and proliferative processes determines the enlargement of a tumor. Accurate measurement of apoptotic and proliferative rates from diagnostic prostate biopsies would allow calculation of tumor growth rates in a population-based prostate cancer (CaP) study. Automated image analysis may be used if proliferation and apoptotic biomarkers provide clearly resolved immunostained images.

METHODS

Clinical CaP aggressiveness was assigned as low, intermediate or high using clinical criteria for 46 research subjects with newly diagnosed CaP. Diagnostic biopsy sections from the research subjects were dual-labeled for proliferation biomarker, Ki-67 and apoptotic biomarker, apoptotic chromatin condensation inducer in the nucleus (ACINUS). Apoptotic biomarkers, caspase-3 and terminal deoxyribonucleotidyltransferase mediated dUTP-biotin nick end labeling (TUNEL) were labeled separately. Images from immunostained sections were analyzed using automated image analysis and tumor growth rates computed. Association between clinical CaP aggressiveness and tumor growth rates was explored.

RESULTS

Sixteen subjects had high, 17 had intermediate, and 13 had low clinical CaP aggressiveness. Positive immunostaining was localized to the nucleus for Ki-67, ACINUS, and TUNEL. A statistically significant linear trend across clinical CaP aggressiveness categories was found when tumor growth rates were calculated using ACINUS (P = 0.046). Logistic regression and ROC plots generated showed ACINUS (AUC = 0.677, P = 0.048) and caspase-3 (AUC = 0.694, P = 0.038) to be better predictors than TUNEL (AUC = 0.669, P = 0.110).

CONCLUSIONS

ACINUS met the criteria for automated image analysis and for calculation of apoptotic rate. Tumor growth rates determined using automated image analysis should be evaluated for clinical prediction of CaP aggressiveness, treatment response, recurrence, and mortality.

Expression of cellular adhesion molecule 'OPCML' is down-regulated in gliomas and other brain tumours

The four GPI-anchored cell adhesion molecules that exemplify the IgLON family are most highly expressed in the nervous system and associate to form up to six different heterodimeric 'Diglons' that can modify cell adhesion and inhibit axon migration. Recently, two members, OPCML and LSAMP, were identified as putative tumour suppressor genes in ovarian and renal carcinomas respectively. In this study, we investigated OPCML expression in nonneoplastic brain tissue and 35 brain tumours (18 glioblastoma multiformes, five anaplastic gliomas, five meningiomas, six metastases and one medulloblastoma) and four glioma cell lines using quantitative reverse transcriptase polymerase chain reaction (RT-PCR). OPCML was highly expressed in cerebellum, less so in cerebral cortex, frontal lobe and meninges and was significantly reduced or absent in 83% of brain tumours and all cell lines compared with nonneoplastic whole brain. Two OPCML splice variants have been identified in humans, termed alpha1 and alpha2, but the latter has not been demonstrated in human neural tissues. Using PCR with specific primers, nonneoplastic brain and 3/6 of tested brain tumours expressed both splice variants, whereas the remaining brain tumours only expressed the alpha2 variant. Hypermethylation of the alpha1 OPCML promoter, associated with down-regulation of expression in ovarian tumours, did not correlate with expression levels in the subset of brain tumours tested, implying transcription of OPCML from an alternative promoter or a different mechanism of down-regulation. This study demonstrates that OPCML down-regulation occurs in the majority of brain tumours tested, warranting further investigation of OPCML and other IgLONs in the development and progression of brain tumours.

Immunohistochemical expression of peripheral benzodiazepine receptors in human astrocytomas and its correlation with grade of malignancy, proliferation, apoptosis and survival

Peripheral benzodiazepine receptors (PBR) are widely distributed in peripheral tissues, astrocytes, and microglia of the brain. They are involved in apoptosis, proliferation, and many other processes, such as steroidogenesis in adrenal glands, male and female gonads, biological adaptation to stress, etc. It has been established that the expression of PBR in astrocytomas is higher than in the normal brain. The goal of this study was to explore the correlation of the immunohistochemical expression of PBR in astrocytomas with the grade of malignancy and rates of apoptosis, proliferation and survival. In 130 cases of astrocytomas (25 grade I, 25 grade II, 20 grade III, 60 grade IV), paraffin sections were stained immunohistochemically for PBR and MIB-1(Ki-67). TUNEL assay was used for evaluation of apoptosis. It was found that the intensity and extent of staining for PBR had a strong direct correlation with the grade of malignancy of the tumor, along with proliferative and apoptotic indices. The highest expression of PBR was in glioblastomas grade IV, especially around areas of necrosis. There was a strong negative correlation between PBR expression and survival. The results of this study may be applied in the pathological diagnosis of astrocytomas as an additional clue in establishing tumor grade; they may be used in the imaging of astrocytomas, both for diagnosis and follow-up, by the application of positron emission tomography scanning with PBR specific ligands. Targeting of PBR in high-grade gliomas may be a promising approach, achieving more specific anti-tumor effect.

T-cell apoptosis in human glioblastoma multiforme: Implications for immunotherapy

We used immunohistochemistry and flow cytometry to assess apoptosis in human glioblastoma multiforme (GBM). Our immunohistochemical study revealed apoptosis of glioma cells expressing glial fibrillary acidic protein and of CD3(+) T cells infiltrating GBM. To quantify and phenotype the apoptotic T cells, we performed flow cytometry on lymphocytes separated from GBM. The cells were stained with annexin-V-FLUOS/propidium iodide to identify apoptosis. We found that high proportions of both the CD4(+) and CD8(+) T cells were apoptotic. In particular, we found that T cells expressing Fas ligand (Fas-L, CD95L) were eight times more vulnerable to apoptosis than those not expressing Fas-L, which suggests that the T-cell apoptosis is induced by overactivation of the T-cell receptor, possibly in the absence of appropriate costimulation. Our results have implications for the design of immunotherapies for GBM.

Role of MIB1 in predicting survival in patients with glioblastomas

BACKGROUND

Histologic immunomarkers of cell cycle proteins have been utilized for prognosis in high-grade astrocytic tumors. One such marker, MIB1, an antibody immunoreactive throughout the cell cycle, is predictive of more aggressive disease and poorer prognosis in astrocytomas. An independent role of MIB1 analysis for survival prediction and clinical management within histologic grades has not been clearly proven.

METHODS

This study retrospectively evaluated MIB1 reactivity in tissue samples from 116 patients with glioblastomas on initial medical presentation. Clinical variables considered included gender, age, Karnofsky Performance Scores (KPS), extent of surgical resection, adjuvant radiation and survival.

RESULTS

Univariate and multivariate analyses were used to correlate these variables with MIB1 staining. MIB1 staining does not predict overall survival or response to adjuvant therapy as an independent risk factor.

CONCLUSION

MIB1 labeling does not predict patient survival as an independent variable and does not predict response to additional therapies. Patient survival with glioblastoma was predicted by KPS, age, extent of resection and use of adjuvant radiotherapy.

Gene expression profile of glioblastoma multiforme invasive phenotype points to new therapeutic targets

The invasive phenotype of glioblastoma multiforme (GBM) is a hallmark of malignant process, yet molecular mechanisms that dictate this locally invasive behavior remain poorly understood. Gene expression profiles of human glioma cells were assessed from laser capture-microdissected GBM cells collected from paired patient tumor cores and white matter-invading cell populations. Changes in gene expression in invading GBM cells were validated by quantitative reverse transcription polymerase chain reaction (QRT-PCR) and immunohistochemistry in an independent sample set. QRT-PCR confirmed the differential expression in 19 of 21 genes tested. Immunohistochemical analyses of autotaxin (ATX), ephrin B3, B-cell lymphoma-w (BCLW), and protein tyrosine kinase 2 beta showed them to be expressed in invasive glioma cells. The known GBM markers, insulin-like growth factor binding protein 2 and vimentin, were robustly expressed in the tumor core. A glioma invasion tissue microarray confirmed the expression of ATX and BCLW in invasive cells of tumors of various grades. GBM phenotypic and genotypic heterogeneity is well documented. In this study, we show an additional layer of complexity: transcriptional differences between cells of tumor core and invasive cells located in the brain parenchyma. Gene products supporting invasion may be novel targets for manipulation of brain tumor behavior with consequences on treatment outcome.

Apoptosis in gliomas: molecular mechanisms and therapeutic implications

Understanding apoptosis is often considered a key to understand the genesis of tumors and to devise innovative strategies for their treatment. Similar to other types of cancer, essential pathways regulating apoptosis are also disrupted in malignant gliomas, notably the cell cycle control mechanisms regulated by the p53 and retinoblastoma (RB) proteins and their homologs. Moreover, cultured glioma cells appear not to activate the extrinsic death receptor-dependent apoptotic pathway in response to irradiation or cytotoxic drugs. A preferential expression of antiapoptotic rather than proapoptotic BCL-2 family proteins and high level expression of inhibitor-of-apoptosis proteins (IAP) may be responsible for the failure of glioma cells to activate caspases in response to apoptotic stimuli. Although apoptosis does occur spontaneously in malignant gliomas in vivo, there is little evidence that the current modes of non-surgical treatment, radiotherapy and chemotherapy, mediate their effects via induction of apoptosis, with the possible exception of anaplastic oligodendrogliomas which often show striking tumor regression on neuroimaging. Yet, the induction of apoptosis plays a conceptual role in the majority of novel experimental approaches to malignant glioma which are currently evaluated in cell culture and preclinical rodent models.

Heat stress induces different forms of cell death in sea anemones and their endosymbiotic algae depending on temperature and duration

Bleaching of reef building corals and other symbiotic cnidarians due to the loss of their dinoflagellate algal symbionts (=zooxanthellae), and/or their photosynthetic pigments, is a common sign of environmental stress. Mass bleaching events are becoming an increasingly important cause of mortality and reef degradation on a global scale, linked by many to global climate change. However, the cellular mechanisms of stress-induced bleaching remain largely unresolved. In this study, the frequency of apoptosis-like and necrosis-like cell death was determined in the symbiotic sea anemone Aiptasia sp. using criteria that had previously been validated for this symbiosis as indicators of programmed cell death (PCD) and necrosis. Results indicate that PCD and necrosis occur simultaneously in both host tissues and zooxanthellae subject to environmentally relevant doses of heat stress. Frequency of PCD in the anemone endoderm increased within minutes of treatment. Peak rates of apoptosis-like cell death in the host were coincident with the timing of loss of zooxanthellae during bleaching. The proportion of apoptosis-like host cells subsequently declined while cell necrosis increased. In the zooxanthellae, both apoptosis-like and necrosis-like activity increased throughout the duration of the experiment (6 days), dependent on temperature dose. A stress-mediated PCD pathway is an important part of the thermal stress response in the sea anemone symbiosis and this study suggests that PCD may play different roles in different components of the symbiosis during bleaching.

Secreted Protein Acidic, Rich in Cysteine (SPARC), Mediates Cellular Survival of Gliomas through AKT Activation

Secreted protein acidic, rich in cysteine (SPARC), is an extracellular matrix protein expressed in many advanced cancers, including malignant gliomas. We and others have previously shown that human glioma cell lines engineered to overexpress SPARC adopt an invasive phenotype. We now show that SPARC expression increases cell survival under stress initiated by serum withdrawal through a decrease in apoptosis. Phosphatidylinositol 3-OH kinase/AKT is a potent pro-survival pathway that contributes to the malignancy of gliomas. Cells expressing SPARC display increased AKT activation with decreased caspase 3/7 activity. Exogenous SPARC rapidly induces AKT phosphorylation, an effect that is blocked by a neutralizing SPARC antibody. Furthermore, AKT activation is essential for the anti-apoptotic effects of SPARC as the decreased apoptosis and caspase activity associated with SPARC expression can be blocked with dominant-negative AKT or a specific AKT inhibitor. As tumor cells face stressful microenvironments particularly during the process of invasion, these results suggest that SPARC functions, in part, to promote tumor progression by enabling tumor cells to survive under stressful conditions.

Opposite role of Bax and BCL-2 in the anti-tumoral responses of the immune system

Background

The relative role of anti apoptotic (i.e. Bcl-2) or pro-apoptotic (e.g. Bax) proteins in tumor progression is still not completely understood.

Methods

The rat glioma cell line A15A5 was stably transfected with human Bcl-2 and Bax transgenes and the viability of theses cell lines was analyzed in vitro and in vivo.

Results

In vitro, the transfected cell lines (huBax A15A5 and huBcl-2 A15A5) exhibited different sensitivities toward apoptotic stimuli. huBax A15A5 cells were more sensitive and huBcl-2 A15A5 cells more resistant to apoptosis than mock-transfected A15A5 cells (pCMV A15A5). However, in vivo, in syngenic rat BDIX, these cell lines behaved differently, as no tumor growth was observed with huBax A15A5 cells while huBcl-2 A15A5 cells formed large tumors. The immune system appeared to be involved in the rejection of huBax A15A5 cells since i) huBax A15A5 cells were tumorogenic in nude mice, ii) an accumulation of CD8+ T-lymphocytes was observed at the site of injection of huBax A15A5 cells and iii) BDIX rats, which had received huBax A15A5 cells developed an immune protection against pCMV A15A5 and huBcl-2 A15A5 cells.

Conclusions

We show that the expression of Bax and Bcl-2 controls the sensitivity of the cancer cells toward the immune system. This sensitization is most likely to be due to an increase in immune induced cell death and/or the amplification of an anti tumour immune response

Expression of the pro-apoptotic protein ARTS in astrocytic tumors

BACKGROUND

Apoptosis (i.e., programmed cell death) plays a major role in the development of astrocytic tumors, which are the most common tumors of the central nervous system. ARTS, a proapoptotic protein that is localized in the mitochondria, promotes apoptosis by functioning as an XIAP antagonist and a caspase activator.

METHODS

To investigate the role of ARTS in astrocytoma, the authors examined protein expression and apoptotic activity in 72 astrocytic tumors, which included low-grade astrocytomas, anaplastic astrocytomas, and glioblastomas.

RESULTS

Whereas normal astrocytes did not express the ARTS protein, astrocytoma cells strongly expressed ARTS, and the expression of this protein increased with increasing tumor grade. Furthermore, increased levels of ARTS were significantly associated with higher rates of apoptosis (as measured using the terminal deoxynucleotidyltransferase-mediated deoxyuridine triphosphate nick end-labeling [TUNEL] assay as well as an immunohistochemical staining assay for active caspase-3) in these tumors. Levels of two other apoptosis-related proteins, p53 and Bcl-2, also were examined using immunohistochemical methods; ARTS expression was found to be positively correlated with expression of the former and negatively correlated with expression of the latter, which is known to possess antiapoptotic activity.

CONCLUSIONS

The results of the current study suggest that ARTS levels reliably reflect the ability of cells to undergo apoptosis, which serves as a defense mechanism against the development and progression of astrocytoma. Furthermore, ARTS expression, when taken into consideration in combination with tumor grade, was the only independent predictor of survival identified in the current analysis. Thus, the authors conclude that ARTS may possess utility as a prognostic marker, as well as a therapeutic tool, for patients with astrocytoma.