Origin, migration and fate of newly generated neurons in the adult rodent piriform cortex

Newly generated neurons are continuously added to the olfactory epithelium and olfactory bulbs of adult mammals. Studies also report newly generated neurons in the piriform cortex, the primary cortical projection site of the olfactory bulbs. The current study used BrdU-injection paradigms, and in vivo and in vitro DiI tracing methods to address three fundamental issues of these cells: their origin, migratory route and fate. The results show that 1 day after a BrdU-injection, BrdU/DCX double-labeled cells appear deep to the ventricular subependyma, within the white matter. Such cells appear further ventral and caudal in the ensuing days, first appearing in the rostral piriform cortex of mice at 2 days after the BrdU-injection, and at 4 days in the rat. In the caudal piriform cortex, BrdU/DCX labeled cells first appear at 4 days after the injection in mice and 7 days in rats. The time it takes for these cells to appear in the piriform cortex and the temporal distribution pattern suggest that they migrate from outside this region. DiI tracing methods confirmed a migratory route to the piriform cortex from the ventricular subependyma. The presence of BrdU/NeuN labeled cells as early as 7 days after a BrdU injection in mice and 10 days in the rat and lasting as long as 41 days indicates that some of these cells have extended survival durations in the adult piriform cortex.

Histone Acetyltransferase hALP and Nuclear Membrane Protein hsSUN1 Function in De-condensation of Mitotic Chromosomes

Replicated mammalian chromosomes condense to segregate during anaphase, and they de-condense at the conclusion of mitosis. Currently, it is not understood what the factors and events are that specify de-condensation. Here, we demonstrate that chromosome de-condensation needs the function of an inner nuclear membrane (INM) protein hsSUN1 and a membrane-associated histone acetyltransferase (HAT), hALP. We propose that nascently reforming nuclear envelope employs hsSUN1 and hALP to acetylate histones for de-compacting DNA at the end of mitosis.

A heterozygous mutation disrupting the SPAG16 gene results in biochemical instability of central apparatus components of the human sperm axoneme

The SPAG16 gene encodes two major transcripts, one for the 71-kDa SPAG16L, which is the orthologue of the Chlamydomonas rheinhardtii central apparatus protein PF20, and a smaller transcript, which codes for the 35-kDa SPAG16S nuclear protein that represents the C-terminus (exons 11-16) of SPAG16L. We have previously reported that a targeted mutation in exon 11 of the Spag16 gene impairs spermatogenesis and prevents transmission of the mutant allele in chimeric mice. In the present report, we describe a heterozygous mutation in exon 13 of the SPAG16 gene, which causes a frame shift and premature stop codon, affording the opportunity to compare mutations with similar impacts on SPAG16L and SPAG16S for male reproductive function in mice and men. We studied two male heterozygotes for the SPAG16 mutation, both of which were fertile. Freezing-boiling of isolated sperm from both affected males resulted in the loss of the SPAG16L protein, SPAG6, another central apparatus protein that interacts with SPAG16L, and the 28-kDa fragment of SPAG17, which associates with SPAG6. These proteins were also lost after freezing-boiling cycles of sperm extracts from mice that were heterozygous for an inactivating mutation (exons 2 and 3) in Spag16. Our findings suggest that a heterozygous mutation that affects both SPAG16L and SPAG16S does not cause male infertility in man, but is associated with reduced stability of the interacting proteins of the central apparatus in response to a thermal challenge, a phenotype shared by the sperm of mice heterozygous for a mutation that affects SPAG16L.

Induction of autophagy does not affect human rhinovirus type 2 production

Induction of autophagy has been shown to be beneficial for the replication of poliovirus, a phenomenon that might also apply for other picornaviruses. We demonstrate that de novo synthesis of human rhinovirus type 2 (HRV2), an HRV of the minor receptor group, is unaffected by tamoxifen, rapamycin, and 3-methyladenine (3-MA), drugs either stimulating (tamoxifen and rapamycin) or inhibiting (3-MA) autophagic processes. Furthermore, LC3-positive vesicles (i.e., autophagosomes) are not induced upon infection. Therefore, multiplication of this particular picornavirus is not dependent on autophagy.

Survivin and its prognostic significance in pediatric acute B-cell precursor lymphoblastic leukemia

BACKGROUND AND OBJECTIVES

Impaired apoptosis, mediated by members of the inhibitor of apoptosis proteins (IAP) family such as survivin, is thought to contribute to leukemic cell survival. In contrast to low expression of survivin in normal differentiated adult tissues, very high levels of survivin have been described in a number of different tumors. Overexpression of survivin was found to correlate with poor prognosis in a variety of cancers including hematologic malignancies. To date, however, there is no information available on the prognostic role of survivin in pediatric precursor B-cell acute lymphocytic leukemia (BCP-ALL), the most frequent malignancy in childhood.

DESIGN AND METHODS

In a retrospective study including 66 pediatric patients we analyzed the impact of survivin protein levels on outcome in BCP-ALL.

RESULTS

Survivin overexpression, with an up to ten-fold increase of the normal level, was detected in 65% of the leukemic samples in contrast to negligible expression in non-malignant hematopoietic cells. Despite considerable variety of expression levels in ALL cells, there was no association of survivin levels with established risk factors. However, patients suffering relapse of disease or death had significantly higher survivin expression than those with a favorable outcome. Overexpression of survivin is a significant prognostic marker for 3 year relapse free, event-free and overall survival, again independent of the established prognostic factors in ALL, such as age and leukocyte count at diagnosis as assessed in multivariate analysis.

INTERPRETATION AND CONCLUSIONS

Overexpression of survivin in BCP-ALL identifies patients with a high risk of early relapse. Upon confirmation in a prospective analysis, survivin expression may, in the future, serve to further refine treatment stratification with intensification of therapy in those patients prone to relapse.

Forced expression of survivin-2B abrogates mitotic cells and induces mitochondria-dependent apoptosis by blockade of tubulin polymerization and modulation of Bcl-2, Bax, and survivin

It has been previously shown that both survivin and the survivin splice variant survivin-2B are localized in mitochondria. Whereas the mechanism involved in blockade of mitochondria-mediated apoptosis by survivin has been extensively studied, the role of survivin-2B in regulation of apoptosis has not been well defined. In the present study, we report that in addition to mitochondria, survivin-2B is also localized in the microtubule organization center (MTOC) and, in contrast to other survivin isoforms (i.e. survivin and survivin-DeltaEx3), behaves as a proapoptotic molecule. We show that forced expression of survivin-2B blocks tubulin polymerization, ablates mitotic cells, and induces mitochondria-dependent apoptosis. The mitochondria-mediated apoptosis induced by survivin-2B was indicated by Smac release from mitochondria, activation of caspases 9 and 3, and loss of mitochondrial potential, while caspase-8 remained inactive. Further analysis of the mechanism for the mitochondria-associated events of apoptosis induced by forced expression of survivin-2B revealed down-regulation of the pro-survival factor Bcl-2 and up-regulation of the pro-apoptotic factor Bax in mitochondria, while the apoptosis-inducing factor (AIF) remains unchanged. Our studies further showed that taxol (paclitaxel) treatment of cancer cells not only up-regulates survivin but also down-regulates survivin-2B and that forced expression of survivin-2B sensitizes cells to taxol-induced cell growth inhibition and cell death, while silencing of endogenous survivin-2B transcripts by survivin-2B-specific siRNA made cells resistant to taxol treatment. These findings advance our current knowledge about survivin-2B and may help to develop novel approaches for cancer treatment.

The NMDAR subunit NR3A interacts with microtubule-associated protein 1S in the brain

When screening a brain cDNA library, we found that the N-methyl-D-aspartate receptor subunit NR3A binds to microtubule-associated protein (MAP) 1S/chromosome 19 open reading frame 5 (C19ORF5). The interaction was confirmed in vitro and in vivo, and binding of MAP1S was localized to the membrane-proximal part of the NR3A C-terminus. MAP1S belongs to the same family as MAP1A and MAP1B, and was found to be abundant in both postnatal and adult rat brain. In hippocampal neurons the distribution-pattern of MAP1S resembled that of beta-tubulin III, but a fraction of the protein colocalized with synaptic markers synapsin and postsynaptic density protein 95 (PSD95), in beta-tubulin III-negative filopodia-like protrusions. There was coexistance between MAP1S and NR3A immunoreactivity in neurite shafts and occasionally in filopodia-like processes. MAP1S potentially links NR3A to the cytoskeleton, and may stabilize NR3A-containing receptors at the synapse and regulate their movement between synaptic and extrasynaptic sites.

Localization of EB1, IFT polypeptides, and kinesin-2 in Chlamydomonas flagellar axonemes via immunogold scanning electron microscopy

Intraflagellar transport (IFT) refers to the bi-directional movement of particles and associated cargo along the axonemes of eukaryotic flagella and cilia. To provide a new perspective on the morphology of IFT particles, their association with the axoneme, and their composition, we have used immunogold localization coupled to detection via scanning electron microscopy. Here we co-localize in the Chlamydomonas flagellar axoneme polypeptides labeled with specific antibodies. Chlamydomonas EB1 localizes to the distal tip of the axoneme, as expected from previous immunofluorescent data (Pedersen et al. Curr Biol2003;13(22):1969-1974), thus demonstrating the utility of this approach. Using antibodies to IFT-related polypeptides, particles can be identified associated with the axoneme that fall into one of two classes: The first class is composed of IFT particles labeled with polyclonal antibodies to kinesin-2 and monoclonal antibodies to either IFT139 (an IFT complex A polypeptide) or IFT172 (a complex B polypeptide). The second class is comprised of particles that label with antibodies to IFT139 alone; thus, discrete particles are present associated with the axoneme that are composed only of complex A polypeptides. When IFT particles were purified by sucrose gradient ultracentrifugation, they appeared as more or less spherical aggregates of varying dimensions labeled with antibodies to IFT139 and to the motor protein kinesin-2. By contrast, isolated IFT particles that were labeled with IFT172 antibodies were not labeled with kinesin-2 antibodies. The data are discussed in terms of the total polypeptide composition of an IFT particle and the interaction of the particles with the motors that power IFT.

Comparison of Digestion Protocols for Microgram Quantities of Enriched Protein Samples

Standard biochemical techniques that are used for protein enrichments, such as affinity isolation and density gradient centrifugation, frequently yield high-nanogram to low-microgram quantities at a significant expenditure of resources and time. The characterization of selected protein enrichments by the "shotgun" mass spectrometry approach is often compromised by the lack of effective and efficient in-solution proteolysis protocols specifically tailored for these small quantities of proteins. This study compares the results of five different digestion protocols that were applied to 2.5 mug portions of protein isolates from two disparate sources: Rhodopseudomonas palustris 70S ribosomal proteins, and Bos taurus microtubule-associated proteins (MAPs). Proteolytic peptides produced according to each protocol in each type of protein isolate were analyzed by one-dimensional liquid chromatography-tandem mass spectrometry (LC-MS/MS). The effectiveness of each digestion protocol was assessed on the basis of three parameters: number of peptide identifications, number of protein identifications, and sequence coverage. The two protocols using a solvent containing 80% acetonitrile (CH3CN) for trypsin digestions performed as well as, and in some instances better than, protocols employing other solvents and chaotropes in both types of protein isolates. A primary advantage of the 80% CH3CN protocol is that it requires fewer sample manipulation steps.

Inhibition of Stat3 activation and tumor growth suppression of non-small cell lung cancer by G-quartet oligonucleotides

Lung cancer is the leading cause of cancer mortality in the United States. Despite advances made over the past decades, the overall survival of patients with lung cancer remains dismal. Here we report novel G-quartet oligodeoxynucleotides (GQ-ODN) that were designed to selectively target signal transducer and activator of transcription 3 (Stat3), in the treatment of human non-small cell lung cancer (NSCLC). The objective of this study was to evaluate the effects of two novel GQ-ODN STAT3 inhibitors, T40214 and T40231, on NSCLC bearing nude mice. NSCLC bearing nude mice were assigned to 5 groups, which were treated by vehicle, control ODN, T40214, T40231, and Paclitaxel, respectively. Tumors were measured, isolated and analyzed using Western blotting, immuno-histochemistry, RPA and TUNEL. Results show that GQ-ODN T40214 and T40231 significantly suppress the growth of NSCLC tumors in nude mice by selectively inhibiting the activation of Stat3 and its downstream proteins Bcl-2, Bcl-xL, Mcl-1, survivin, VEGF, Cyclin D1 and c-myc; thereby, promoting apoptosis and reducing angiogenesis and cell proliferation. These findings validate Stat3 as an important molecular target for NSCLC therapy and demonstrate the efficacy of GQ-ODN in inhibiting Stat3 phosphorylation.

Survivin is a downstream target and effector of sulindac-sensitive oncogenic Stat3 signalling in head and neck cancer

Sulindac exerts its antitumorigenic effects in oral squamous cell carcinoma (SCC) cells by modulating survivin in a Stat3-dependent manner. Immunohistochemistry was used to detect the protein levels of phosphorylated-tyrosine Stat3 (p-tyr Stat3) and survivin in SCC tissues. Western blot, reverse transcriptase polymerase chain reaction, Annexin-V and cell proliferation assays were used to determine p-tyr Stat3 and survivin protein and mRNA expression, and cell viability following treatment with cyclooxygenase (COX) inhibitors, Stat3 siRNA, or the forced expression of Stat3 or survivin. Immunohistochemical analysis revealed an overexpression of p-tyr Stat3 in T1 SCCs. The importance of constitutive Stat3 activation in tumourigenesis was confirmed by siRNA inhibition of Stat3, resulting in cell growth inhibition and apoptosis, via a downregulation of survivin mRNA and protein expression. The forced expression of survivin partially reversed these effects of Stat3 inhibition. Sulindac, but not other COX inhibitors, downregulated Stat3, which correlated to an inhibition of cell proliferation, survival and survivin expression. Transfection of constitutively active Stat3 restored survivin expression and partially rescued SCC cells from sulindac-induced antitumorigenic effects. These data indicate that survivin is a downstream target and effector of oncogenic Stat3 signalling in SCC, which is targeted by sulindac in a COX-2-independent manner.

Reactive changes of retinal astrocytes and Müller glial cells in kainate-induced neuroexcitotoxicity

The aim of this study was to investigate reactive changes of astrocytes and Müller glial cells in rats subjected to kainate treatment, which leads to neuronal degeneration in the ganglion cell layer and the inner border of the inner nuclear layer as confirmed by labelling with Fluoro-Jade B, a marker for degenerating neurons and fibres. Both the astrocytes and the Müller glial cells reacted vigorously to kainate injection as shown by their up-regulated expression of nestin, glial fibrillary acidic protein and glutamine synthetase. A major finding was the induced expression of nestin together with glial fibrillary acidic protein beginning at 1 day post-injection of kainate. The marked nestin expression appeared to be most intense at 1 day and was sustained till 2 weeks as compared with the untreated/normal retina. Western blotting analysis confirmed a marked increase in expression of nestin, glial fibrillary acidic protein and glutamine synthetase as compared with untreated/normal retina. Double labelling study revealed that astrocytes and Müller glial cells expressed the radial glia marker nestin, and incorporated bromodeoxyuridine to re-enter into their cell cycle. The induced expression of these proteins in astrocytes and Müller glial cells indicated an induction of gliotic responses and de-differentiation that may be associated with regenerative efforts after kainate-induced injury. Indeed, with the acquisition of an immature molecular profile as manifested by the induced expression of brain lipid-binding protein and doublecortin in astrocytes and Müller glial cells, the potential of these cells to de-differentiate in retinal neurodegeneration is greatly amplified.

Cytoplasmic dynein and LIS1 are required for microtubule advance during growth cone remodeling and fast axonal outgrowth

Recent evidence has implicated dynein and its regulatory factors dynactin and LIS1 in neuronal and non-neuronal cell migration. In the current study we sought to test whether effects on neuronal cell motility might reflect, in part, a role for these proteins in the growth cone. In chick sensory neurons subjected to acute laminin treatment dynein, dynactin, and LIS1 were mobilized strikingly and rapidly to the leading edge of the growth cone, where they were seen to be associated with microtubules converging into the laminin-induced axonal outgrowths. To interfere acutely with LIS1 and dynein function and to minimize secondary phenotypic effects, we injected antibodies to these proteins just before axon initiation. Antibody to both proteins produced an almost complete block of laminin-induced growth cone remodeling and the underlying reorganization of microtubules. Penetration of microtubules into the peripheral zone of differentiating axonal growth cones was decreased dramatically by antibody injection, as judged by live analysis of enhanced green fluorescent protein-tubulin and the microtubule tip-associated EB3 (end-binding protein 3). Dynein and LIS1 inhibition had no detectable effect on microtubule assembly but reduced the ability of microtubules to resist retrograde actin flow. In hippocampal neurons dynein, dynactin, and LIS1 were enriched in axonal growth cones at stage 3, and both growth cone organization and axon elongation were altered by LIS1 RNA interference. Together, our data indicate that dynein and LIS1 play a surprisingly prominent role in microtubule advance during growth cone remodeling associated with axonogenesis. These data may explain, in part, the role of these proteins in brain developmental disease and support an important role in diverse aspects of neuronal differentiation and nervous system development.

Effective killing of the human pathogen Candida albicans by a specific inhibitor of non-essential mitotic kinesin Kip1p

Kinesins from the bipolar (Kinesin-5) family are conserved in eukaryotic organisms and play critical roles during the earliest stages of mitosis to mediate spindle pole body separation and formation of a bipolar mitotic spindle. To date, genes encoding bipolar kinesins have been reported to be essential in all organisms studied. We report the characterization of CaKip1p, the sole member of this family in the human pathogenic yeast Candida albicans. C. albicans Kip1p appears to localize to the mitotic spindle and loss of CaKip1p function interferes with normal progression through mitosis. Inducible excision of CaKIP1 revealed phenotypes unique to C. albicans, including viable homozygous Cakip1 mutants and an aberrant spindle morphology in which multiple spindle poles accumulate in close proximity to each other. Expression of the C. albicans Kip1 motor domain in Escherichia coli produced a protein with microtubule-stimulated ATPase activity that was inhibited by an aminobenzothiazole (ABT) compound in an ATP-competitive fashion. This inhibition results in ‘rigor-like’, tight association with microtubules in vitro. Upon treatment of C. albicans cells with the ABT compound, cells were killed, and terminal phenotype analysis revealed an aberrant spindle morphology similar to that induced by loss of the CaKIP1 gene. The ABT compound discovered is the first example of a fungal spindle inhibitor targeted to a mitotic kinesin. Our results also show that the non-essential nature and implementation of the bipolar motor in C. albicans differs from that seen in other organisms, and suggest that inhibitors of a non-essential mitotic kinesin may offer promise as cidal agents for antifungal drug discovery.

Radiotherapy response in oral squamous carcinoma cell lines: evaluation of apoptotic proteins as prognostic factors

BACKGROUND

In this study, we investigated the importance of apoptosis for cell death after radiotherapy, and whether the expression of pro- and anti-apoptotic proteins has any correlation to the radiosensitivity.

METHODS

Three oral squamous cell carcinoma cell lines, UT-SCC-2, UT-SCC-9 and UT-SCC-24A, were subjected to radiotherapy. After irradiation, viable and dead cells were counted to determine radiation sensitivity and apoptosis was analyzed by measurement of caspase-3 activity. The expressions of pro- and anti-apoptotic proteins were assessed using western blot analyses.

RESULTS AND CONCLUSION

After irradiation, apoptotic morphology and caspase-3 activity were only detected in cell lines exhibiting high or moderate radiosensitivity. Western blot analysis indicates that survivin, epidermal growth factor receptor, cyclooxygenase-2, and Bcl-x(L) are critical components in irradiation resistance of the investigated cell lines. Moreover, our results suggest that apoptotic cell death and the balance between pro- and anti-apoptotic proteins are of importance for the outcome of radiotherapy.

NuSAP is degraded by APC/C-Cdh1 and its overexpression results in mitotic arrest dependent of its microtubules' affinity

Microtubule associated proteins are involved in regulation of microtubule dynamics. Its mutation and dysregulation result in severe consequences such as mitotic block and apoptosis. NuSAP has been reported as a microtubule associated protein, depletion of which by RNAi results in spindle deficiency and cytokinesis failure. However, its role in regulation of cell cycle and how NuSAP protein is controlled during cell cycle progression still remains unclear. Here we show that NuSAP can be ubiquitinated and degraded by APC/C-hCdh1 E3 ligase. Evolutionally conserved KEN box functions as the degron of NuSAP. Overexpression of NuSAP induces mitotic arrest and the microtubule associated domain and nuclear localization are both required for NuSAP to induce mitotic arrest. Furthermore, overexpression of NuSAP results in cells accumulation with microtubule bundling and spindle deficiency. Thus, our results give evidence for the first time that NuSAP protein level is tightly regulated by the APC/C ubiquitin ligase complex and NuSAP induces mitotic arrest dependent of its microtubule affinity.

The novel proangiogenic effect of hydrogen sulfide is dependent on Akt phosphorylation

OBJECTIVE

Hydrogen sulfide (H(2)S) has been reported to be a gasotransmitter which regulates cardiovascular homeostasis. The present study aims to examine the hypothesis that hydrogen sulfide is able to promote angiogenesis.

METHODS

Angiogenesis was assessed using in vitro parameters (i.e. endothelial cell proliferation, adhesion, transwell migration assay, scratched wound healing and formation of tube-like structure) and in vivo by assessing neovascularization in mice. Phosphorylation of Akt was measured using Western blot analysis.

RESULTS

Exogenously administered NaHS (H(2)S donor) concentration-dependently (10-20 micromol/l) increased cell growth, migration, scratched wound healing and tube-like structure formation in cultured endothelial cells. These effects of NaHS on endothelial wound healing and tube-like structure formation were prevented by either the phosphatidylinositol 3-kinase (PI3K) inhibitor LY 294002 (5 micromol/l) or transfection of a dominant-negative mutant of Akt. NaHS increased Akt phosphorylation and this effect was also blocked by either LY 294002 or wortmannin (25 nmol/l). NaHS did not significantly alter the levels of vascular endothelial growth factor, mRNA expression of fibroblast growth factor and angiopoietin-1, or nitric oxide metabolites. NaHS treatment (10 and 50 micromol kg(-1) day(-1)) significantly promoted neovascularization in vivo in mice.

CONCLUSION

The present study reports a novel proangiogenic role of H(2)S which is dependent on activation of Akt.

Microtubule-associated protein 1B binds glyceraldehyde-3-phosphate dehydrogenase

Microtubule-associated protein 1B, MAP1B, is a major cytoskeletal protein during brain development and one of the largest brain MAPs associated with microtubules and microfilaments. Here, we identified several proteins that bind to MAP1B via immunoprecipitation with a MAP1B-specific antibody, by one and two-dimensional gel electrophoresis and subsequent mass spectrometry identification of precipitated proteins. In addition to tubulin and actin, a variety of proteins were identified. Among these proteins were glyceraldehyde-3-phosphate dehydrogenase (GAPDH), heat shock protein 8, dihydropyrimidinase related proteins 2 and 3, protein-L-isoaspartate O-methyltransferase, beta-spectrin, and clathrin protein MKIAA0034, linking either directly or indirectly to MAP1B. In particular, GAPDH, a key glycolytic enzyme, was bound in large quantity to the heavy chain of MAP1B in adult brain tissue. In vitro binding studies confirmed a direct binding of GAPDH to MAP1B. In PC12 cells, GAPDH was found in cytoplasm and nuclei and partially co-localized with MAP1B. It disappeared from the cytoplasm under oxidative stress or after a disruption of cytoskeletal elements after colcemid or cytochalasin exposure. GAPDH may be essential in the local energy provision of cytoskeletal structures and MAP1B may help to keep this key enzyme close to the cytoskeleton.

Survivin expression is associated with bladder cancer presence, stage, progression, and mortality

BACKGROUND

The purpose was to compare the differential expression of Survivin in normal bladder tissue, bladder transitional cell carcinoma (TCC) of different stages, and to determine whether expression of Survivin is associated with TCC clinical outcomes.

METHODS

Immunohistochemical staining for Survivin was carried out on archival bladder specimens from 9 normal controls and 222 consecutive patients who underwent radical cystectomy and bilateral lymphadenectomy. Lymph node tissue involved with TCC from 50 of the 222 cystectomy patients was also evaluated.

RESULTS

Survivin was expressed in none of the normal bladder specimens, 64% of the cystectomy specimens, and 94% of the malignant lymph nodes. Multivariable analyses performed in the cystectomy patients revealed that Survivin expression was associated with disease recurrence (P = .040), disease-specific mortality (P = .037), and all-cause mortality (P = .044).

CONCLUSIONS

The findings of the study provide a rationale for further evaluation of Survivin and its downstream signaling pathways in bladder cancer and raise the potential for Survivin-targeted therapy for bladder cancer.

Correlation of quantitative MRI and neuropathology in epilepsy surgical resection specimens--T2 correlates with neuronal tissue in gray matter

Newer MRI methods can detect cerebral abnormalities not identified on routine imaging in patients with focal epilepsy. Correlation of MRI with histopathology is necessary to understand the basis of MRI abnormalities and subsequently predict histopathology from in vivo MRI. The aim of this study was to determine if particular quantitative MR parameters were associated with particular histological features.

Nine patients with temporal lobe epilepsy were imaged at 1.5 T using standard presurgical volumetric and quantifiable sequences: magnetization transfer and FFT2. The resected temporal lobe was registered with the volumetric MRI data according to our previously described method to permit correlation of the modalities. Stereologically measured neuronal densities and field fraction of GFAP, MAP2, synaptophysin and NeuN immunohistochemistry were obtained. Analyses were performed in the middle temporal gyrus and compared with quantitative MRI data from the equivalent regions.

There was a significant Spearman Rho negative correlation between NeuN field fraction and the T2 value in gray matter (correlation coefficient − 0.72, p = 0.028). There were no significant correlations between any neuropathological and MR measures in white matter.

These preliminary findings suggest that T2 in gray matter is sensitive to the proportion of neuronal tissue. Novel quantitative MRI measures acquired with higher field strength magnets, and so with superior signal to noise ratios, may generate data that correlate with histopathological measures. This will enable better identification and delineation of the structural causes of refractory focal epilepsy, and will be of particular benefit in patients in whom current optimal MRI does not identify a relevant abnormality.

Expression of anaplastic lymphoma kinase, tyrosine-phosphorylated STAT3, and associated factors in pediatric anaplastic large cell lymphoma: A report from the children's oncology group

In anaplastic large cell lymphoma (ALCL), anaplastic lymphoma kinase (ALK) activates (phosphorylates) signal transducer and activator of transcription 3 (STAT3) with subsequent cytoplasmic expression, in some cases, of survivin and tissue inhibitor of metalloprotease 1 (TIMP1). These are inhibitors of apoptosis and negative prognostic factors. CD56 is also a negative prognostic marker in ALCL. We assayed 40 cases of predominantly ALK+ pediatric ALCL for pSTAT3, survivin, TIMP1, and CD56 using immunohistochemical analysis. The patients were derived from a Pediatric Oncology Group treatment protocol that showed 72% event-free survival at 4 years for ALCL. The results show that in advanced-stage pediatric ALCL, although most tumors express ALK and a majority show activated STAT3, cytoplasmic localization of survivin and TIMP1 is not frequent, nor is expression of CD56. This may help, in part, explain the relatively good prognosis of pediatric ALCL.

Expression patterns of inhibitor of apoptosis proteins in malignant pleural mesothelioma

Inhibitor of apoptosis proteins (IAPs) comprise a family of structurally similar proteins, five of which are widely studied in the context of cancer: IAP-1/MIHC/cIAP2, IAP-2/MIHB/cIAP1, livin/ML-IAP/KIAP, survivin, and XIAP/MIHA/hILP. IAPs are overexpressed by most neoplasms, promote tumour cell survival after a wide variety of apoptotic stimuli, and frequently have gene and/or protein expression patterns associated with a relatively poor prognosis. However, many IAPs are also expressed by normal tissues, can facilitate apoptotic cell death, and have expression patterns associated with a relatively favourable prognosis in some cases. The result is that the precise role(s) of IAPs in human tumours is not exactly known. It has been previously reported that IAP-1 is overexpressed in malignant pleural mesothelioma (MPM) and is responsible for a large degree of the resistance of cultured MPM cells to cisplatin. Given the high homology of IAP family members, it is likely that other IAPs will be important in MPM. In the present study, the gene and protein expression patterns of IAP-1, IAP-2, survivin, livin, and XIAP have been determined in MPM cell lines (n=9) and a large number of MPM tumours using high-density oligonucleotide microarrays (n=40) and an MPM tissue array (n=66). Human tumours were linked to clinical data and it was found that IAP-1 and survivin mRNA expression patterns were associated with a relatively shorter patient survival, while those of XIAP and livin were associated with a relatively longer patient survival. Abundant protein for all IAPs was also detected in MPM tumours, where they were expressed primarily in the cytoplasm. Only IAP-1 and livin protein was expressed in the nucleus of MPM tumours. These results provide the rationale for additional study of this gene family in MPM and cancer in general.

Inhibitor of apoptosis proteins are regulated by tumour necrosis factor-alpha in malignant pleural mesothelioma

Inhibitor of apoptosis proteins (IAPs) are overexpressed by most neoplasms and promote tumour cell survival after a wide variety of apoptotic stimuli elicited via intrinsic (ie mitochondrial) and extrinsic (ie death receptor) pathways. It has previously been reported that one of these proteins, IAP-1(MIHC/cIAP2), is overexpressed in malignant pleural mesothelioma (MPM) and is responsible for a large degree of the resistance of cultured MPM cells to cisplatin. Subsequent analysis in a larger number of human tumours revealed that additional IAPs (eg IAP-2/MIHB/cIAP1, livin/ML-IAP/KIAP, survivin, and XIAP/MIHA/hILP) are also overexpressed in MPM and, with the exception of IAP-2, have expression patterns that correlate with prognosis. In the present study, potential regulatory mechanisms of IAP genes in MPM were investigated and it was found that tumour necrosis factor-alpha (TNF-alpha) can increase mRNA and protein levels of IAP-1, IAP-2, and XIAP, but not livin or survivin in MPM cell lines (n=4). It was also found that IAP gene expression levels are increased concomitantly with translocation to the nucleus of the TNF-responsive transcription factor NF-kappaB. Co-incubation of MPM cells with TNF-alpha and pyrrolidine dithiocarbamate (PDTC), an NF-kappaB inhibitor, prevented TNF-mediated up-regulation of IAP gene expression levels. In survival studies, TNF-alpha was not toxic to MPM cells at any concentration examined. However, MPM cells exposed to TNF-alpha were twice as resistant to cisplatin in dose response survival assays compared with unstimulated controls and were found to have a significantly greater fraction of surviving cells at multiple cisplatin concentrations (p<0.0087). Finally, it was found that levels of circulating TNF-alpha were statistically significantly (p=0.031) (median 312.5 pg/ml) higher in MPM patients (n=6) prior to surgical tumour debulking compared with those after surgery (median 0 pg/ml). These results when combined with previous observations by our laboratory and others strongly suggest that IAPs act synergistically with TNF family members to promote survival of MPM tumour cells after exposure to cisplatin and possibly other chemotherapeutic drugs.

Sulindac induces apoptosis and inhibits tumor growth in vivo in head and neck squamous cell carcinoma

Sulindac has antineoplastic effects on various cancer cell lines; consequently, we assessed sulindac's effects on laryngeal squamous cell carcinoma (SCC) cells in vitro and in vivo. In vitro, SCC (HEP-2) cells treated with various cyclooxygenase inhibitors or transfected with constitutively active signal transducer and activator of transcription 3 (Stat3) or survivin vectors were analyzed using Western blot analysis, annexin V assay, and cell proliferation assay. In parallel, nude mice injected subcutaneously with HEP-2 cells were either treated intraperitoneally with sulindac or left untreated, and analyzed for tumor weight, survivin expression, and tyrosine-phosphorylated Stat3 expression. In vitro studies confirmed the selective antiproliferative and proapoptotic effects of sulindac, which also downregulated Stat3 and survivin protein expression. Stat3 or survivin forced expression partially rescued the antiproliferative effects of sulindac. In vivo studies showed significant repression of HEP-2 xenograft growth in sulindactreated mice versus controls, with near-complete resolution at 10 days. Additionally, tumor specimens treated with sulindac showed downregulation of phosphorylated tyrosine-705 Stat3 and survivin expression. Taken together, our data suggest, for the first time, a specific inhibitory effect of sulindac on tumor growth and survivin expression in laryngeal cancer, both in vitro and in vivo, in a Stat3-dependent manner, suggesting a novel therapeutic approach to head and neck cancer.

Dynamic intracellular survivin in oral squamous cell carcinoma: underlying molecular mechanism and potential as an early prognostic marker

Survivin functions as an apoptosis inhibitor and a regulator of cell division in many tumours. The intracellular localization of survivin in tumours has been suggested as a prognostic marker. However, current reports are inconsistent and the underlying molecular mechanisms are not understood. The present study has examined the localization and prognostic value of nuclear and cytoplasmic survivin in the pre-therapeutic biopsies from 71 oral and oropharyngeal squamous carcinoma (OSCC) patients. Statistical analysis indicated that preferential nuclear versus cytoplasmic survivin correlated with favourable versus unfavourable disease outcome. Uni- and multi-variate analysis showed that in contrast to total survivin expression, the difference between nuclear and cytoplasmic survivin was a strong predictor for relapse-free survival (p=0.0003). As a potential underlying molecular mechanism, it is shown in OSCC cell lines that predominantly cytoplasmic survivin mediates protection against chemo- and radio-therapy-induced apoptosis. Importantly, the cytoplasmic localization of survivin is regulated by its nuclear export signal (NES), and export-deficient nuclear survivin is not cytoprotective. This study suggests that the difference between cytoplasmic and nuclear survivin is an indicator for survivin activity in tumour cells. Thus, this difference may serve as a predictive marker of outcome in OSCC patients undergoing multi-modality therapy. The pharmacogenetic interference with survivin's cytoplasmic localization is also to be pursued as a potential therapeutic strategy.