Expression of survivin, an inhibitor of apoptosis protein, in tumors of the nervous system

Tetraploidy/aneuploidy and stem cells in cancer promotion: The role of chromosome passenger proteins

While polyploidy, a state of having fully duplicated sets of chromosomes per cell, has been described in normally developing bone marrow megakaryocytes or as an adaptive response in other cell types, aneuploidy is never detected in normal cells. Tetraploidy or aneuploidy can be induced by several signals and it is highly prevalent in different forms of cancers, suggesting a role for this cell cycle state in promoting cellular transformation. Investigations suggested that loss of heterozygosity of cancer-related genes in stem cells might contribute to genetic instability in progeny cells and to subsequent cancer development. Deregulated expression of chromosome passenger proteins, such as Aurora kinases or Survivin, is a hallmark of various cancers, and experimentally induced changes in these regulators can promote tetraploidy or aneuploidy and loss of heterozygosity. Our studies described an induction of tetraploidy/aneuploidy by a stable form of Aurora-B, leading to acquisition of transformation properties. It is intriguing to speculate that in some cancers, tetraploidy/aneuploidy induced by deregulated expression of a mitotic regulator represents a primary event that leads to unbalanced expression of a cluster of crucial genes and to cellular transformation.

Survivin: an inhibitor of apoptosis in pediatric cancer

Survivin is an inhibitor of apoptosis protein (IAP) expressed in a large number of adult malignancies. Its expression levels correlate with more aggressive disease and poor clinical outcome in many of these tumors. As its expression is restricted in normal adult differentiated tissues, it has become of great interest as both a tumor prognostic marker and as a potential biologic target for future anti-cancer therapies. Survivin expression and Survivin-based therapies have been examined in many of the more common pediatric malignancies. We present an overview of Survivin function and current research exploring its biologic and therapeutic roles in pediatric tumors.

The human survivin promoter: a novel transcriptional targeting strategy for treatment of glioma

Object

Malignant brain tumors have been proved to be resistant to standard treatments and therefore require new therapeutic strategies. Survivin, a recently described member of the inhibitor of apoptosis protein family, is overexpressed in several human brain tumors, primarily gliomas, but is downregulated in normal tissues. The authors hypothesized that the expression of tumor-specific survivin could be exploited for treatment of gliomas by targeting the tumors with gene therapy vectors.

Methods

Following confirmation of survivin expression in glioma cell lines, an adenoviral vector containing the survivin promoter and the reporter gene luciferase was tested in established and primary glioma cells, normal astrocytic cells, and normal human brain tissues. High levels of reporter gene expression were observed in established tumor and primary tumor cell lines and low levels of expression in astrocytes and normal human brain tissue. To test oncolytic potency, the authors constructed survivin promoter–based conditionally replicative adenoviruses (CRAds), composed of survivin promoter–regulated E1 gene expression and an RGD-4C capsid modification. These CRAds could efficiently replicate within and kill a variety of established glioma tumor cells, but were inactive in a normal human liver organ culture. Finally, survivin promoter–based CRAds significantly inhibited the growth of glioma xenografts in vivo.

Conclusions

Together these data indicate that the survivin promoter is a promising tumor-specific promoter for transcriptional targeting of adenovirus-based vectors and CRAds for malignant gliomas. The strategy of using survivin–CRAds may thus translate into an experimental therapeutic approach that can be used in human clinical trials.

Expression of cytoplasmic and nuclear Survivin in primary and secondary human glioblastoma

Clinically, human glioblastoma (GBM) may develop de novo or from a low-grade glioma (secondary GBM), and molecular alterations in the two pathways may differ. This study examined the status of Survivin expression and apoptosis in 30 primary and 26 secondary GBMs. Our results show that cytoplasmic Survivin positivity was significantly (P<0.001) more frequent in primary GBMs (83%) than that in secondary GBMs (46%). In addition, an inverse correlation of cytoplasmc Survivin positivity with GBM apoptotic index, and a positive association between cytoplasmic Survivin and size of the tumours were observed. These results suggest that cytoplasmic Survivin, via its antiapoptotic function, may be involved in the tumorigenesis of many primary GBMs, but only in a small fraction of secondary GBMs. Furthermore, the overall progression times from low-grade precursor lesions to secondary GBMs were significantly shorter (P<0.05) in cytoplasmic Survivin-positive cases (mean, 15.6 months) than those in Survivin-negative cases (mean, 23.8 moths), and the positive expression level of Survivin in cytoplasm was upregulated in most secondary GBMs when compared to matched pre-existing low-graded lesions. These results suggest that the increased accumulation of Survivin in the cytoplasm of more malignant glioma cells may prove to be a selective advantage, thus accelerating progression to a more aggressive phenotype.

Molecular neuro-oncology and the development of targeted therapeutic strategies for brain tumors. Part 5: apoptosis and cell cycle

Brain tumors are a diverse group of malignancies that remain refractory to conventional treatment approaches. Molecular neuro-oncology has now begun to clarify the transformed phenotype of brain tumors and identify oncogenic pathways that might be amenable to targeted therapy. Abnormalities of the apoptotic and cell cycle signaling pathways are key molecular features of many brain tumors and are currently under evaluation for potential therapeutic intervention. The apoptosis pathway has numerous targets for molecular therapeutic development, including p53, Bax, Bcl-2, cFLIP, effector caspases, growth factor receptors, phosphatidylinositol-3-kinase, Akt and apoptosis inhibitors. Current molecular treatment approaches include antisense techniques, gene therapy and small-molecule modulators and inhibitors. Potential targets of the cell cycle pathway include the cyclins, cyclin-dependent kinases, p53, retinoblastoma, E2F and the cyclin-dependent kinase inhibitors. Developmental molecular therapeutics for this pathway include adenoviral and gene therapy, small-peptide cyclin-dependent kinase modulators, proteasomal inhibitors and small-molecule cyclin-dependent kinase inhibitors. Several of these recently identified agents have begun evaluation in clinical trials. Further development of targeted therapies designed to modulate apoptosis and the cell cycle, and evaluation of these new agents in clinical trials, will be needed to improve survival and quality of life for patients with brain tumors.

Survivin expression and its relation with proliferation, apoptosis, and angiogenesis in brain gliomas

BACKGROUND

An unbalance of cell proliferation and cell apoptosis is an important mechanism in carcinogenesis, and angiogenesis also plays a crucial role in tumorigenesis. Recently, survivin has been identified as an important member of the inhibitor of apoptosis protein (IAP) family. Although it has been shown that survivin is highly expressed in gliomas, and is associated with tumorigenesis, progression, and poor prognosis of gliomas, as yet the relation of survivin expression with proliferation, apoptosis, and angiogenesis of gliomas it is still unclear.

METHODS

Eighty-three cases of brain glioma were chosen and protein expressions of survivin and proliferating cell nuclear antigen (PCNA) in glioma cells and Factor VIII-related antigen (FVIII-RAg) in vascular endothelial cells were investigated by immunohistochemistry. Apoptotic cells of brain glioma were screened by TdT-mediated dUTP nick end-labeling (TUNEL), and survivin immunoreactivity score (IRS), proliferative index (PI), apoptotic index (AI), overall daily growth (ODG), and microvessel density (MVD) in brain gliomas were measured.

RESULTS

The survivin IRS, PI, AI, ODG, and MVD of brain gliomas were 3.75 +/- 3.89, 28.39 +/- 19.49%, 1.00 +/- 0.80%, 12.19 +/- 10.21%, and 62.75 +/- 31.50, respectively, and all of them increased markedly with an increase in the pathologic grade of brain gliomas (P < 0.001 for all). PI, ODG, and MVD in the survivin-positive group were significantly higher than those in the survivin-negative group (P < 0.001 for all). PI, ODG, and MVD were positively correlated with survivin IRS (P < 0.001 for all). Although there was no significant difference between AI in the survivin-positive group or in the survivin-negative group (P = 0.108), AI was inversely correlated with survivin IRS (P = 0.005).

CONCLUSIONS

Survivin is overexpressed in brain gliomas, which may play an important role in malignant proliferation, antiapoptosis, and angiogenesis of brain gliomas.

Cell-specific DNA fragmentation may be attenuated by a survivin-dependent mechanism after traumatic brain injury in rats

Survivin attenuates apoptosis by inhibiting cleavage of some cell proteins by activated caspase-3. We recently discovered strong up-regulation of survivin, primarily in astrocytes and a sub-set of neurons, after traumatic brain injury (TBI) in rats. In this study we characterized co-expression of survivin with activated caspase-3 and downstream DNA fragmentation (TUNEL) in astrocytes and neurons after TBI. Western blot analysis revealed significant time-dependent increases in active caspase-3 between 5 and 14 days post-injury. No difference was observed between the proportion of survivin-positive and survivin-negative cells labeled with active caspase-3 at 5 or 7 days post-injury, as indicated by dual fluorescent immunostaining. Labeling of survivin-negative cells with TUNEL was, however, significantly greater than for survivin-positive cells, suggesting that expression of survivin may attenuate DNA cleavage and progression of apoptosis. A higher proportion of astrocytes than neurons accumulated active caspase-3. In contrast, co-localization with TUNEL was significantly higher for neurons than for astrocytes. These data suggest that survivin expression may attenuate DNA cleavage and cell death, and that this mechanism operates in a cell type-specific manner after TBI.

Survivin is a negative prognostic marker in medulloblastoma

Survivin is a member of the inhibitor of apoptosis protein family, which is over-expressed in many human cancers. Our aim was to analyse survivin expression in medulloblastoma, its association with aberrant activation of the WNT (wingless) pathway and to test the prognostic significance of survivin expression. We immuno histochemically analysed survivin expression and localization of beta-catenin, a downstream mediator of the WNT pathway, in 56 cases of medulloblastoma. Survivin was detected in the nuclei of tumour cells in all cases, but the proportion of positive nuclei varied from 0.5 to 31.3%. Survivin expression tended to be higher in medulloblastomas with an aberrant activation of the WNT pathway (nuclear localization of beta-catenin), but did not correlate with histological type, age group or dissemination via cerebrospinal fluid pathways. Survivin expression and dissemination status were two independent negative prognostic variables for the overall survival of patients with medulloblastoma. In conclusion, survivin is up-regulated in medulloblastomas. It is a negative prognostic marker and a potential therapeutic target.

Neuronal intranuclear inclusion disease in a horse

Neuronal intranuclear inclusion disease (NIID) is reported in a 16-year-old Pure Spanish breed female horse suffering from progressive ataxia and motor deficiencies. The neuropathological study revealed NIIs throughout the central nervous system, although mainly in the brain stem and spinal cord. This distribution did not correlate with neuron loss, which was marked in the hippocampus and moderate in the neocortex, particularly in the occipital cortex. As in humans, NIIs in the horse were hyaline autofluorescent inclusions composed of non-membrane-bound aggregates of filaments and fine granules. NIIs were stained with anti-ubiquitin and anti-clusterin antibodies. In addition, NIIs were stained with antibodies raised against subunits of the 19S and PA28, but not of the 20S, components of the proteasome. These observations indicate similarities between NIID in humans and horses, and suggest that clusterin and abnormal ubiquitin-proteasomal expression participate in NII formation.

No prognostic impact of survivin expression in glioblastoma

Survivin is a member of a novel protein family of inhibitors of apoptosis, and also plays a role as a potent regulator of mitosis. In semiquantitative Western blot analysis of glioblastomas, survivin expression was shown to be a prognostically significant factor. In the present study we investigated the immunohistochemical expression of survivin and its prognostic impact in a large glioblastoma series comprising 104 consecutive adult patients undergoing a first operation for glioblastoma. We analyzed survivin, Ki-67, and topoisomerase-II-alpha expression in paraffin-embedded tissue, and correlated patient age, Karnofsky performance score, vascular pattern and survivin-, Ki-67-, topoisomerase-II-alpha-, and apoptotic indices with patient outcome using univariate and multivariate survival analysis. Survivin was expressed in all glioblastoma samples, and was prominent in a fraction of nuclei of tumor cells and vascular cells. Further, survivin labeled spindle- and chromosomal material of mitotic figures. Faint cytoplasmic expression was also seen. The survivin index showed significant correlation with Ki-67 and Topo-II-alpha indices. On average, 58.85% of Ki-67 and 91.08% of survivin-expressing nuclei co-expressed Ki-67 and survivin. The survivin index did not correlate significantly with overall survival, whereas patient age, Karnofsky performance score, vascular pattern, and Ki-67 and topoisomerase-II-alpha indices were associated with patient outcome. In summary, in glioblastoma, survivin is expressed predominantly in proliferating tumor cell nuclei. In contrast to Ki-67 and topoisomerase-II-alpha, survivin expression does not influence patient outcome. So, in contrast to Ki-67, survivin does not seem to be useful as prognostic factor in the clinical setting.

Apoptotic markers for primary brain tumor prognosis

Molecular studies of brain tumors have provided insights into pathogenesis, yet it is unclear how important these markers are in predicting clinical outcome and response to treatment. Quantitation of apoptosis by various techniques and the expression of several apoptotic markers have been studied in brain tumors, seeking to refine the information gained from established prognostic variables, which traditionally dictate therapeutic approaches. In the present review we discuss the role of the most extensively examined molecules involved in the apoptotic procedure, such as bcl-2, bax, fas/fasL, survivin and p53, as well as the incidence of baseline apoptosis in various brain tumors, in relation to prognosis. Summarizing current evidence, increased apoptosis and p53 genetic alterations have been advanced as adverse prognosticators in various types of central nervous system neoplasms, while bcl-2 expression appears to be deprived of any predictive value in primary brain tumors. The prognostic significance of the remaining apoptosis-related molecules remains controversial or too limited to draw any firm conclusions. The lack of unanimity of results mostly based on single-center retrospective studies underscores the necessity for large prospective randomized clinical trials, to elucidate the role of these molecular markers as determinants of clinical decision-making and as potential correlates of a pathobiologically tailored and individualized treatment strategy.

Survivin, Survivin-2B, and Survivin-deItaEx3 expression in medulloblastoma: biologic markers of tumour morphology and clinical outcome

Survivin is an apoptotic inhibitor that is expressed at high levels in a variety of malignancies. Survivin has four known alternative splice forms (Survivin, Survivin-2B, Survivin-deltaEx3, and Survivin-3B), and the recent literature suggests that these splice variants have unique functions and subcellular localisation patterns. We evaluated 19 fresh-frozen paediatric medulloblastomas for the expression of three Survivin isoforms by quantitative PCR. Survivin was most highly expressed when compared with normal cerebellar tissue. We also investigated Survivin protein expression in 40 paraffin-embedded paediatric medulloblastoma tumours by immunohistochemistry. We found a statistically significant association between the percentage of Survivin-positive cells and histologic subtype, with the large-cell-anaplastic variant expressing Survivin at higher levels than the classic subtype. We also found a statistically significant relationship between the percent of Survivin-positive cells in the tumours and clinical outcome, with higher levels of Survivin correlating with a worse prognosis. In summary, our study demonstrates a role for Survivin as a marker of tumour morphology and clinical outcome in medulloblastoma. Survivin may be a promising future prognostic tool and potential biologic target in this malignancy.

Expression of MATH1, a marker of cerebellar granule cell progenitors, identifies different medulloblastoma sub-types

In order to look for genetic markers helpful for the biological risk stratification of medulloblastomas (MBs) we assayed by real-time PCR expression levels of the following genes: MATH1, encoding a critical transcription factor for the differentiation of cerebellar granular cells (CGCs); PEDF, that encodes a trophic factor for CGCs and is located in a region of frequent allelic imbalance in MBs; and BIRC5, encoding the antiapoptotic protein survivin, usually overexpressed in malignancies. Expression levels of TRKC, higher in MBs with a more favorable prognosis, were also studied. Twenty-three patients were considered: MATH1 expression was strong in 14/23 and undetectable in the others. PEDF was up-regulated in 8/23, TRKC in 9/23, and BIRC5 in 23/23. MATH1 expression was significantly correlated with adult age (p < 0.0001), tumor location in hemispheres rather than the vermis (p < 0.0004), and PEDF and TRKC up-regulation (p < 0.008 and p < 0.04, respectively). During development MATH1 is selectively expressed in the external germinal layer (EGL) of the cerebellum. Thus, MATH1 expression identifies a subgroup of MBs that derive from the EGL and arise during adult age into cerebellar hemispheres. MATH1 mRNA-positive MBs express high levels of PEDF and show a trend towards longer survival, in agreement with increased expression of TRKC. BIRC5 expression, which is strong in all MBs and absent in normal cerebellum, lacks any prognostic value but could be explored for selective targeting of therapeutic factors to MBs.

Upregulation of clusterin/apolipoprotein J in lactacystin-treated SH-SY5Y cells

Clusterin (apolipoprotein J) is a highly conserved, multifunctional, vertebrate glycoprotein. Several isoforms of clusterin have been described including the predominant secreted isoform (sCLU) and several nuclear isoforms (nCLU) associated with cell death. sCLU has been shown to bind a variety of partly unfolded, stressed proteins including those associated with Lewy bodies (LBs) in patients with Parkinson's disease (PD). The development of familial and sporadic PD has been associated with the ubiquitin-proteasome system (UPS) dysfunction and aberrant protein degradation. This suggests that failure of the UPS to degrade abnormal proteins may underlie nigral degeneration and LB formation in PD. The effects of toxin-mediated proteasomal impairment on changes in gene expression and cell viability were studied in differentiated SH-SY5Y cells. Clusterin expression was increased in cells exposed for 24 hr to the proteasomal inhibitor lactacystin (10 microM) as determined by gene microarray analysis. RT-PCR showed that sCLU, not nCLU, was the major clusterin isoform expressed in both control and lactacystin-treated cells. Western blot analysis identified statistically significant increases in sCLU in total cell lysates after 24 hr of lactacystin exposure and showed that sCLU fractionates with the endoplasmic reticulum. Time-course studies demonstrated that maximal decreases in proteasome activity (4 hr) preceded maximal increases in clusterin expression (24 hr). Together these data suggest that proteasome impairment results in the upregulation of sCLU in SH-SY5Y cells, supporting the hypothesis that the association of clusterin with LBs in PD may be related to UPS failure.

Association of apolipoprotein J-positive beta-amyloid plaques with dystrophic neurites in Alzheimer's disease brain

Apolipoprotein J (apoJ), also known as clusterin and SP-40,40, binds soluble beta-amyloid (Abeta and is up-regulated in the Alzheimer's disease (AD) brain. In the present study we classified apoJ-immunopositive Abeta deposits in AD temporal cortex, and found apoJ-immunoreactive plaques were often associated with dystrophic neurites. Quantitative immunohistochemical analysis of five AD brains showed that 29% of Abeta deposited in the parenchyma was associated with apoJ. Of Abeta deposits with apoJ immunopositivity, 71% were associated with phospho-tau-positive dystrophic neurites in the surrounding tissue. Conversely, 64% of phospho-tau-labeled neuritic deposits were labeled with apoJ. ApoJ was found at the core of these deposits, and co-localized with the amyloid staining agent thioflavine-S. To test the direct effects of apoJ on tau metabolism, we treated cells in culture with apoJ-containing conditioned media, and we injected apoJ-containing media into the rat hippocampus. Using both systems, we observed increases in levels of tau and phosphorylated tau. Our findings demonstrate that apoJ immunopositivity strongly correlates with the presence of amyloid and associated neuritic dystrophy in the neuropil of AD temporal cortex, and supports a model where extracellular apoJ facilitates the conversion of diffuse Abeta deposits into amyloid and enhances tau phosphorylation in neurites surrounding these of plaques.

Cell-specific upregulation of survivin after experimental traumatic brain injury in rats

In this study, we examined the expression and cellular localization of survivin and proliferating cell nuclear antigen (PCNA) after controlled cortical impact traumatic brain injury (TBI) in rats. There was a remarkable and sustained induction of survivin mRNA and protein in the ipsilateral cortex and hippocampus of rats after TBI, peaking at five days post injury. In contrast, both survivin mRNA and protein were virtually undetectable in craniotomy control animals. Concomitantly, expression of PCNA was also significantly enhanced in the ipsilateral cortex and hippocampus of these rats with similar temporal and spatial patterns. Immunohistochemistry revealed that survivin and PCNA were co-expressed in the same cells and had a focal distribution within the injured brain. Further analysis revealed a frequent co-localization of survivin and GFAP, an astrocytic marker, in both the ipsilateral cortex and hippocampus, while a much smaller subset of cells showed co-localization of survivin and NeuN, a mature neuronal marker. Neuronal localization of survivin was observed predominantly in the ipsilateral cortex and contralateral hippocampus after TBI. PCNA protein expression was detected in both astrocytes and neurons of the ipsilateral cortex and hippocampus after TBI. Collectively these data demonstrate that the anti-apoptotic protein survivin, previously characterized in cancer cells, is abundantly expressed in brain tissues of adult rats subjected to TBI. We found survivin expression in both astrocytes and a sub-set of neurons. In addition, the expression of survivin was co-incident with PCNA, a cell cycle protein. This suggests that survivin may be involved in regulation of neural cell proliferative responses after traumatic brain injury.

Survivin enhances radiation resistance in primary human glioblastoma cells via caspase-independent mechanisms

The observed radioresistance of human glioblastoma multiforme (GBM) poses a major challenge, which, if overcome, may lead to significant advances in the management of this patient population. There is accumulating evidence from correlative studies that Survivin expression is associated with increased malignant potential of human gliomas. The purpose of this study was to investigate whether Survivin plays a direct role in mediating radiation resistance in primary human glioma cell lines, and, if so, investigating the underlying mechanisms. Our panel of GBM cell lines included two that were relatively radiation resistant (GM20 and GM21) and two that were more radiation sensitive (GM22 and GM23), which demonstrated differential levels of Survivin expression between the two groups. Through the use of adenoviral vectors containing either dominant-negative (pAd-S(T34A)) or wild-type Suvrivin (pAd-S(WT)), we were able to inactivate or overexpress Survivin, respectively. Our findings suggest that Survivin plays a critical role in mediating radiation resistance in primary GBM cells, in part through suppression of apoptotic cell death via a caspase-independent manner. We have identified novel mechanisms by which Survivin may enhance tumor cell survival upon radiation exposure such as regulation of double-strand DNA break repair and tumor cell metabolism, which were most evident in the radiation-resistant cell lines. These differences in Survivin function both in radiation-resistant vs radiation-sensitive cell lines and in the presence vs absence of radiation exposure warrant further investigation and highlight potentially important mechanisms of radiation resistance in these tumors.

Clusterin solubility and aggregation in Creutzfeldt-Jakob disease

Prion protein (PrPC) is a glycolipid-anchored cell membrane syaloglycoprotein that localizes in presynaptic membranes. PrP has the property of aggregating into amyloid fibrils and being deposited in the brains in cases with transmissible encephalopathies (TSEs), when PrPC is converted into abnormal protease-resistant PrP (PrPRES). Clusterin is a heterodimeric glycoprotein, the expression of which is enhanced in astrocytes in association with punctate-type PrPRES deposits during TSE progression. In addition, clusterin co-localizes in PrPRES plaques in several human TSEs, including Creutzfeldt-Jakob disease (CJD). Clusterin is up-regulated in the cerebral cortex and cerebellum in CJD as revealed by DNA micro-array technology. Clusterin expression was examined in seven sporadic cases of CJD (codon 129 genotype, PrP type: 4 MM1, 1 MV1, 1 MV2, 1 VV2) and three age-matched controls by immunohistochemistry, Western blotting and solubility. In addition to small punctate clusterin deposition in the neuropil, single- and double-labeling immunohistochemistry disclosed clusterin localization in PrPRES plaques, which predominated in the cerebellum of cases MV1, MV2 and VV2. Moreover, clusterin in plaques, but not punctate clusterin deposits, was resistant to protease digestion, as revealed in tissue sections pre-incubated with proteinase K. Clusterin in CJD, but not clusterin in control brains, was partially resistant to protease digestion in Western blots of total brain homogenates immunostained with anti-clusterin antibodies, which were processed in parallel with Western blots to PrP, without and with pre-incubation with proteinase K. Protein aggregation was analyzed in brain homogenates subjected to several solvents. PrP was recovered in the deoxycholate fraction in control and CJD cases, but in the SDS fraction only in CJD, thus indicating differences in PrP solubility between CJD and controls. Clusterin was recovered in the cytosolic, deoxycholate and SDS fraction in both CJD and control cases, but only clusterin from CJD was recovered in the urea-soluble fraction and, especially, in the remaining pellet. These findings demonstrate the capacity of clusterin to form aggregates and interact with PrPRES aggregates. The implications of this property are not known, but it can be suggested that clusterin participates in PrP clustering and sequestration, thus modifying PrP toxicity in CJD.

Nuclear expression of Survivin in paediatric ependymomas and choroid plexus tumours correlates with morphologic tumour grade

Survivin is a gene that is widely expressed throughout the development of the normal mammalian embryo. Subcellular localisation of Survivin to both the nucleus and cytoplasm has suggested multiple functional roles, including inhibition of cell death, especially as demonstrated within a variety of malignant cell types, as well as regulation of the mitotic spindle checkpoint. The expression of Survivin has been associated with an adverse clinical outcome in a large number of malignancies. However, nuclear Survivin expression has been described as an independent variable of favourable prognosis in two large clinical studies of breast and gastric carcinomas. Reports of Survivin expression in normal postnatal, differentiated tissues have been restricted to cell types with high proliferative capacities, including vascular endothelium, endometrium, colonic epithelium, and activated lymphocytes. Prior to this report, expression within the normal human brain had not been characterised. Here, we analyse the expression of Survivin in human brain sections obtained from perinatal and paediatric autopsy cases. We report a strikingly high level of expression of Survivin within normal ependyma and choroid plexus (CP). Analysis of corresponding neoplastic tissue in paediatric ependymomas and CP tumours shows that expression of the nuclear form of Survivin correlates with morphologic tumour grade, with a loss of nuclear expression associated with progressive cytologic anaplasia. This pattern of expression supports a hypothesis that Survivin plays a functional role in normal ependymal growth and/or neural stem cell differentiation, and that abnormally low levels of expression of the nuclear form of this protein may be a marker of more aggressive disease and/or higher morphologic grade in ependymal and CP tumours.

Survivin, versatile modulation of cell division and apoptosis in cancer

Survivin is a member of the inhibitor of apoptosis (IAP) gene family that has attracted attention from several viewpoints of basic and translational research. Its cell cycle-regulated expression at mitosis and association with the mitotic apparatus have been of interest to cell biologists studying faithful segregation of sister chromatids and timely separation of daughter cells. Investigators interested in mechanisms of apoptosis have found survivin an evolving challenge: while survivin inhibits apoptosis in vitro and in vivo, this pathway may be more selective as compared to cytoprotection mediated by other IAPs. Finally, basic and translational researchers in cancer biology have converged on survivin as a pivotal cancer gene, not simply for its sharp expression in tumors and not in normal tissues, but also for the potential exploitation of this pathway in cancer diagnosis and therapy. The objective of the present contribution is to line up current evidence and emerging concepts on the multifaceted functions of survivin in cell death and cell division, and how this pathway is being pursued for novel cancer therapeutic strategies.

Survivin and apoptosis control

Survivin is a member of the inhibitor of apoptosis (TAP) gene family that exhibits differential expression in nearly all human cancers but not in most normal tissues. Recent progress identified a multifunctional survivin pathway positioned at the interface between mitotic progression and apoptosis inhibition, and required to preserve viability of dividing tumor cells (Altieri, 2001; Andersen and Thor, 2002; Jaattela, 1999). The unique properties of survivin have recently found concrete applications for cancer detection, diagnosis, and outcome prediction. In addition, targeting the survivin pathway may offer new therapeutic prospects to lower a general survival threshold in cancer cells. This chapter will focus on the current developments in the field of survivin and its role in apoptosis regulation and mitotic progression. Current perspectives on exploiting the survivin pathway for cancer diagnosis and treatment will be highlighted.

Survivin study: what is the next wave?

Survivin, a novel member of inhibitor of apoptosis (IAP) protein family, is aberrantly expressed in cancer but undetectable in normal, differentiated adult tissues. Current studies suggest that survivin is implicated in both control of apoptosis and regulation of cell division. However, due to some inconsistent observations on survivin subcellular localization, there is debate about survivin's function in regulating apoptosis, cell division, or both. This review will discuss concepts, experimental methods, and interesting results that unify the different notions about survivin localization and function or point out gaps of knowledge about controversial issues. The author also intends to review various aspects of survivin studies, which were not emphasized or sufficiently discussed in previous reviews on survivin, and update recent developments that may reveal new applications of disease-oriented therapeutics in the coming years.

Survivin-dependent angiogenesis in ischemic brain: molecular mechanisms of hypoxia-induced up-regulation

Approaches to regulating angiogenesis in the brain, which may diminish parenchymal damage after stroke, are lacking. Survivin, the inhibitor of apoptosis protein, is up-regulated in vitro in vascular endothelial cells by angiogenic factors, including vascular endothelial cell growth factor (VEGF). To evaluate the in vivo role of survivin in the brain in response to hypoxia/ischemia, we used a mouse model of stroke and show that 2 days after permanent middle cerebral artery occlusion, survivin is uniquely expressed by microvessels that form in the peri-infarct and infarct regions. The extent of vascularization of the infarct is dependent on expression of survivin, since vessel density is significantly reduced in mice with heterozygous deficiency of the survivin gene (survivin+/- mice), even though infarct sizes were not different. Hypoxia alone induces survivin expression in the brain, by cultured endothelial cells and by embryonic stem cells, but this response is at least partially independent of VEGF, hypoxia inducible factor 1alpha, or placental growth factor. Delineating the spatiotemporal pattern of expression of survivin after stroke, and the molecular mechanisms by which this is regulated, may provide novel approaches to therapeutically optimize angiogenesis in a variety of ischemic disorders.

Survivin gene expression in early-stage non-small cell lung cancer

Survivin is an inhibitor of apoptosis protein, overexpressed in most human malignancies and implicated in mitosis regulation and preservation of cell viability. In order to investigate the prevalence and clinical significance of survivin in early-stage non-small cell lung carcinoma (NSCLC), survivin mRNA levels and protein expression were evaluated, using quantitative real-time RT-PCR and immunohistochemistry, respectively, in a series of 83 patients with stage I (IA and IB) surgically resected NSCLC. Detectable survivin mRNA levels could be demonstrated in all non-neoplastic lung tissue samples and in the tumours analysed. Survivin mRNA levels were elevated in 80 carcinomas (96%) compared to normal lung (p = 0.008). Among all tumours, survivin transcripts were present at a higher level in squamous cell carcinomas (p = 0.0022). Cytoplasmic and nuclear immunoreactivity was found in 70% and 80% of tumours, respectively and both were present in 54%. Cytoplasmic immunoreactivity correlated with tumour stage (p = 0.019). Survivin expression levels did not correlate with patient survival. In one specimen, cytoplasmic and focal nuclear immunostaining was observed in dysplastic bronchial squamous metaplasia. These results document that survivin overexpression is almost always present in early-stage NSCLC, suggesting that this protein may play a role in lung tumourigenesis. This ubiquitous expression makes survivin an appealing new target for novel therapies in lung cancer. In addition, this study also documents that survivin overexpression could be exploited for diagnostic purposes and that quantitative real-time RT-PCR can be a useful tool for evaluating survivin activation in NSCLC.

Survivin in glioblastomas. Protein and messenger RNA expression and comparison with telomerase levels

CONTEXT

Survivin is a novel inhibitor of apoptosis that acts via a pathway independent of bcl-2. Little is known about its distribution in brain tumors or how it correlates with other biomarkers of malignancy, such as telomerase, an enzyme that plays a critical role in cellular immortalization and cancer biology.

OBJECTIVES

To assess survivin protein expression in gliomas and to compare expression with that of telomerase.

DESIGN

Immunohistochemical staining for survivin protein expression was performed using an antibody developed in our laboratory. Quantitative survivin messenger RNA (mRNA) levels were assessed by reverse transcriptase-polymerase chain reaction. In selected cases, survivin results were compared with quantitative telomerase values analyzed by polymerase chain reaction-based telomerase repeat amplification protocol (TRAP) assay. Twenty-five tumor tissue samples from 16 cases of glioblastoma multiforme (GBM; including multiple tissue samples in 6 patients), 2 grade II gliomas, 4 grade III gliomas, and 3 control temporal lobectomy specimens were studied.

RESULTS

Nuclear immunoreactivity for survivin protein and survivin mRNA were detectable in most glioma samples, regardless of grade. Glioblastoma multiforme demonstrated moderate protein expression and survivin mRNA levels compared to epithelial malignancies previously tested in our laboratory. Although the association of survivin mRNA with the levels of telomerase within the GBM cases did not reach statistical significance, most GBMs also expressed survivin. The quantitative score for survivin mRNA was higher in GBMs than in grade II and III gliomas (P =.02), after accounting for multiple specimens per patient.

CONCLUSIONS

Quantitative survivin mRNA analysis, but not immunohistochemistry, distinguished GBMs from lower grade gliomas. Mechanisms that promote both cell proliferation (telomerase expression) and cell survival (survivin expression) are often activated in GBMs.

Expression of survivin protein in human colorectal carcinogenesis

AIM: To identify the role of survivin in colorectal carcinogenesis and the relationship between Survivin and histological differentiation grade of colorectal carcinoma.

METHODS: Immunohistochemical staining of survivin by using the monoclonal antibody was performed by the standard streptavidin-peroxidase (SP) technique for the 188 paraffin sections which included 30 normal colorectal mucosas, 41 adenomas with low grade dysplasia, 30 adenomas with high grade dysplasia, and 87 colorectal carcinomas which were classified as high, middle and low differentiated subgroups which included 33, 28, 26 cases respectively.

RESULTS: Expression of survivin was observed in the cytoplasm of adenoma with dysplasia and colorectal carcinoma cells. No immunoreactivity of survivin was seen in normal mucosas. The positive rate of survivin increased in the transition from normal mucosas to adenomas with low grade dysplasia to high grade dysplasia/carcinomas (0.0%, 31.7%, 56.7% and 63.2% respectively). But the difference between high grade dysplasia and carcinomas had no statistical significance. Positive rate was not related to histological differentiation grade of colorectal carcinoma. Moreover, there was no correlation between histological differentiation grade of colorectal carcinoma and immunoreactive intensity of survivin.

CONCLUSION: The expression of survivin is the essential event in the early stage of colorectal carcinogenesis and plays an important role in the transition sequence and it is not related to histological differentiation grade of colorectal carcinoma. It thus may provide a new diagnostic and therapeutic target in colorectal cancer.

Expression of the inhibitor of apoptosis protein survivin in benign meningiomas

Survivin is a recently characterised inhibitor of apoptosis protein that has been implicated in the pathogenesis of several types of solid organ cancer. This study sought to describe the expression of survivin in a cohort of 90 benign meningiomas, together with the pattern of expression of other genes involved in the apoptotic process, namely bax and bcl2. Survivin expression was noted in 94% (85/90) of samples and was not correlated with the expression of either bax or bcl2 or with clinicopathological factors.

Expression of survivin protein in hepatocellular carcinoma tissues and its relationship with clinical pathological features and prognosis

AIM

To investigate the expression of survivin protein in human hepatocellular carcinoma (HCC) and its relationship with clinical features and prognosis of patients with HCC.

METHODS

The expression of survivin protein and the proliferation of tumor cells marked by PCNA in 48 cases of HCC were assessed by immunohistochemical method. TUNEL method was used to detect apoptosis.

RESULTS

The survivin protein was expressed in 31 of 48 cases of HCC (64.6%). Expression of survivin protein was significantly higher in those of Edmondson grade Ⅲ-Ⅳ than in those of grade Ⅰ-Ⅱ (88.0% vs 39.1%, P = 0.013). The ratio of proliferative index to apoptotic index was significantly higher in HCC with positive survivin expression than that with negative survivin expression (1.8 vs 1.1, P = 0.045). The survival rate of three years of patients with positive survivin expression was significantly lower than that of patients with negative survivin expression (70.6% vs 35.5%, P = 0.011).

CONCLUSION

The expression of survivin may play an important role in breaking the balance of proliferation and apoptosis of HCC cells and is closely associated with prognosis of patients with HCC.