Quick quantitative analysis of gene dosages associated with prognosis in neuroblastoma

17q Gain in Neuroblastoma: A Review of Clinical and Biological Implications

Neuroblastoma (NB) is the most frequent extracranial solid childhood tumor. Despite advances in the understanding and treatment of this disease, the prognosis in cases of high-risk NB is still poor. 17q gain has been shown to be the most frequent genomic alteration in NB. However, the significance of this remains unclear because of its high frequency and association with other genetic modifications, particularly segmental chromosomal aberrations, 1p and 11q deletions, and MYCN amplification, all of which are also associated with a poor clinical prognosis. This work reviewed the evidence on the clinical and biological significance of 17q gain. It strongly supports the significance of 17q gain in the development of NB and its importance as a clinically relevant marker. However, it is crucial to distinguish between whole and partial chromosome 17q gains. The most important breakpoints appear to be at 17q12 and 17q21. The former distinguishes between whole and partial chromosome 17q gain; the latter is a site of IGF2BP1 and NME1 genes that appear to be the main oncogenes responsible for the functional effects of 17q gain.

An Old Flame Never Dies: Survivin in Cancer and Cellular Senescence

Survivin (BIRC5) is highly expressed in the vast majority of human cancers and is associated with chemotherapy resistance, increased tumor recurrence and shortened patient survival, making it an attractive therapeutic target. Initially identified as an inhibitor of apoptosis protein, it also plays a major role in the regulation of cell division. As such, it acts as a subunit of the chromosomal passenger complex, composed of the mitotic kinase aurora B, borealin and inner centromere protein, and is essential for proper chromosome segregation and cytokinesis. For both biological functions, interaction of survivin's nuclear export signal with the nuclear export receptor chromosome region maintenance 1 is absolutely essential. The timely orchestration of survivin's wide protein interaction repertoire is further modulated by different posttranslational modifications occurring in a cell-cycle-dependent manner. Recent data furthermore indicate additional roles of survivin in the DNA damage response, contributing to therapy resistance, yet the underlying molecular details are still not completely resolved. This also holds true for a potential involvement of survivin in senescence regulation. An age-related accumulation of survivin probably contributes to the apoptosis resistance observed in aged as well as in senescent cells, while it might promote escape from therapy-induced senescence. This review seeks to integrate the current knowledge on survivin's diverse and complex biological functions. By linking the 'old' facts about survivin with recent findings in research areas such as DNA damage response and aging, we want to highlight survivin's crucial role in a variety of cellular processes.

Transcriptional regulation of the survivin gene

Survivin, a small member of the inhibitors of the apoptosis protein family, is highly deregulated in cancer. It is weakly expressed in normal tissues but very strongly expressed in malignant lesions. Survivin is involved in cell-cycle progression, especially in the G2/M transition, and has anti-apoptotic activity, which correlates with its strong expression in cases with a poor cancer treatment response and poor outcomes. Several therapies that target the survivin transcript or protein are currently being tested in clinical trials. However, focusing new therapies on the origins of survivin overexpression and targeting these upstream deregulations could be more effective. For this reason, it seems important to make an inventory of the transcriptional (de)regulation of survivin. This review will gather the important points concerning the regulation of survivin mRNA expression: structure of the survivin promoter, epigenetic modifications and genetic abnormalities, transcription factors, and signalling pathways that affect survivin mRNA expression.

The genetic and clinical significance of MYCN gain as detected by FISH in neuroblastoma

PURPOSE

MYCN amplification (MYCN-A) is a strong prognostic factor in neuroblastoma (NB). MYCN gain which is a low level of MYCN-A as determined by FISH. It is unclear whether the MYCN gain is the pre-status of MYCN-A. This study assessed the status of MYCN gene and chromosome 2p of MYCN-A, MYCN gain and no MYCN amplification using a single nucleotide polymorphism (SNP) array, and the clinical implication of MYCN gain in NB.

METHODS

The status of the MYCN gene was determined by FISH in 47 primary NB samples and the status of chromosome 2p in all cases was analyzed using an SNP array.

RESULTS

8 of the 47 cases analyzed using FISH showed MYCN-A, 7 cases showed MYCN gain and 32 cases showed no MYCN amplification. An SNP array analysis showed that only 2 of 8 cases with MYCN-A by FISH had both amplification of MYCN region and distal 2p gain and other 6 cases had amplification of the MYCN region without distal 2p gain. All 7 cases with MYCN gain by FISH had distal 2p gain without amplification of the MYCN region, and all 32 cases with no MYCN amplification by FISH demonstrated neither the amplification of the MYCN region nor the 2p gain. 5-year overall survival rate of patients with MYCN gain (n = 7, 71.4%) was not significant different from that of patients with no MYCN amplification (n = 32, 90.6%) by FISH (p = 0.11).

CONCLUSIONS

These results suggested that the MYCN gain detected by FISH represents the 2p gain, and the MYCN gain is not considered to represent the pre-status of MYCN amplification.

Risks and benefits of ending of mass screening for neuroblastoma at 6 months of age in Japan

PURPOSE

The mass screening (MS) for neuroblastoma (NB) at 6 months of age in Japan was discontinued in 2004. This study assessed the risks and benefits of MS based on an analysis of NB detected before or after discontinuation of MS in Japan.

METHODS

The clinical features and Brodeur's genetic type based on MYCN, DNA ploidy, and other genetic aberrations were assessed in 113 NB patients (20 cases after and 93 cases [55 MS cases] before the discontinuation of MS) older than 6 months treated at one institution since 1985.

RESULTS

The 20 patients with NBs detected after MS was discontinued ranged in age from 7 to 67 months, 12 patients were stage 4, and 11 patients would have been detected at 6 months of age if they had undergone MS. The Brodeur's genetic type of these 20 patients showed that 30% (6/20) were type 1 (low risk), 55% (11/20) were type 2A (intermediate risk), and 15% (3/20) were type 2B (high risk). Of 93 patients with NB detected before MS was discontinued, 60% (56/93) were type 1, 18% (17/93) were type 2A, and 22% (20/93) were type 2B. Among the type 2A patients, 82% (9/11) of the patients detected after MS was discontinued showed stage 4, whereas only 50% (9/18) of those diagnosed before MS was discontinued were stage 4. The genetic analysis using single nucleotide polymorphism (SNP) array for type 2A showed that the pattern of genetic aberration was equivalent in those detected either before or after MS was discontinued.

CONCLUSIONS

There was a decrease of type 1 and an increase of type 2A NB in patients after MS was discontinued in Japan. These results suggest that most of the type 1 detected by MS has regressed, and most of the type 2A detected by MS has appeared sporadically as advanced NB in patients older than 1 year.

Bcl-2 inhibitor HA14-1 and genistein together adeptly down regulated survival factors and activated cysteine proteases for apoptosis in human malignant neuroblastoma SK-N-BE2 and SH-SY5Y cells

Neuroblastoma is a pediatric extracranial tumor and a major cause of death in children under age 2. Conventional therapy shows inefficacy in most cases and thus development of new therapeutic strategies is urgently needed. We explored the efficacy of combination of the small molecule Bcl-2 inhibitor HA14-1 (HA) and the isoflavonoid genistein (GST) in human malignant neuroblastoma SK-N-BE2 and SH-SY5Y cells. Combination of 10 microM HA and 250 microM GST was optimal for SK-N-BE2 cells and combination of 5 microM HA and 100 microM GST was optimal for SH-SY5Y cells for induction of apoptosis. Phase-contrast microscopy and Wright staining showed morphological features of apoptosis. Cell cycle analysis and Annexin V-FITC/PI binding assay showed that combination of HA and GST was more effective in inducing apoptosis in both cell lines than either HA or GST alone. Western blotting showed that combination of HA and GST caused upregulation of Bax and down regulation of Bcl-2 resulting in increased Bax:Bcl-2 ratio and mitochondrial release of cytochrome c, Smac, and AIF. Down regulation of survival factors such as NF-kappaB, N-Myc, and survivin promoted apoptosis. Activation of caspase-8, calpain, and caspase-3 occurred in course of apoptosis. Increased calpain and caspase-3 activities were confirmed in the degradation of alpha-spectrin to 145 kD spectrin break down product (SBDP) and 120 kD SBDP, respectively. Thus, combination of HA and GST could serve as a promising therapeutic strategy for increasing apoptosis in different human malignant neuroblastoma cells.

Repression of BIRC5/survivin by FOXO3/FKHRL1 sensitizes human neuroblastoma cells to DNA damage-induced apoptosis

The phosphatidylinositol 3-kinase (PI3K)-protein kinase B (PKB) pathway regulates survival and chemotherapy resistance of neuronal cells, and its deregulation in neuroblastoma (NB) tumors predicts an adverse clinical outcome. Here, we show that inhibition of PI3K-PKB signaling in human NB cells induces nuclear translocation of FOXO3/FKHRL1, represses the prosurvival protein BIRC5/Survivin, and sensitizes to DNA-damaging agents. To specifically address whether FKHRL1 contributes to Survivin regulation, we introduced a 4-hydroxy-tamoxifen-regulated FKHRL1(A3)ERtm allele into NB cells. Conditional FKHRL1 activation repressed Survivin transcription and protein expression. Transgenic Survivin exerted a significant antiapoptotic effect and prevented the accumulation of Bim and Bax at mitochondria, the loss of mitochondrial membrane potential as well as the release of cytochrome c during FKHRL1-induced apoptosis. In concordance, Survivin knockdown by retroviral short hairpin RNA technology accelerated FKHRL1-induced apoptosis. Low-dose activation of FKHRL1 sensitized to the DNA-damaging agents doxorubicin and etoposide, whereas the overexpression of Survivin diminished FKHRL1 sensitization to these drugs. These results suggest that repression of Survivin by FKHRL1 facilitates FKHRL1-induced apoptosis and sensitizes to cell death induced by DNA-damaging agents, which supports the central role of PI3K-PKB-FKHRL1 signaling in drug resistance of human NB.

Clinical implications of a slight increase in the gene dosage of MYCN in neuroblastoma determined using quantitative PCR

INTRODUCTION

Recently, determining the MYCN status in neuroblastoma (NB) using the quantitative PCR (Q-PCR) and FISH instead of the Southern blotting (SB) has been recommended. In order to assess the implications of the gene dosage of MYCN in NB, the MYCN status was evaluated using Q-PCR on DNA extracted from small areas of NB specimens obtained using laser capture microdissection (LCM).

MATERIALS AND METHODS

MYCN gene dosages (MYCN/NAGK) were determined in 63 primary NB block samples, as well as in 243 microdissected tissues from 63 samples using Q-PCR. In 23 of 63 cases, the MYCN gene status was evaluated using FISH.

RESULTS

Nine block samples with the amplification of MYCN based on SB showed a remarkable increase of the MYCN gene dosage using Q-PCR. Twelve of 54 block samples with no amplification of MYCN based on SB showed a slight increase of the MYCN gene dosage (3.56 > or == MYCN/NAGK > 1.84), and 8 of these 12 cases were in the advanced stage. Among these 12 cases, 1 case had several LCM areas with a high copy number of MYCN and several LCM areas which showed no increase of MYCN gene. Another case showed a slight increase in the MYCN gene dosage (3.65 < or == MYCN/NAGK < or == 4.82) in all LCM areas. In addition, a large number of cells with the MYCN gain were found using FISH in the block sample. In 2 other cases of 12 cases, although no LCM areas showed an increased gene dosage of MYCN, a small number of cells with MYCN amplification were found using FISH were found in the block sample.

CONCLUSION

A slight increase in the gene dosage of MYCN detected by Q-PCR may indicate that the NB tissue contains a small number of cells with the MYCN amplification or a large number of cells with the MYCN gain, which are associated with the aggressive progression of NB.

Fast detection of MYCN copy number alterations in brain neuronal tumors by real-time PCR

Increased MYCN gene copy number is a characteristic property of neurogenic tumors. Fluorescence in situ hybridization (FISH) and array-based comparative genomic hybridization (array-CGH) are traditionally used to determine MYCN amplification for tumor stratification. A unique ability of real-time quantitative polymerase chain reaction (qPCR) to determine gene copy number, even within a small percent of observed tumor cells, and can be more appropriate. MYCN genomic copy number from 44 human brain tumors (22 medulloblastomas and 22 neurocytomas) was determined by means of FISH, array-CGH, and qPCR. By qPCR, with the original set of oligonucleotides, 17 out of 44 (38.6%) tumors were found to contain a 1.3- to 2.9-fold increase of MYCN defined as low-level gain. An absolute qPCR method was used to get high accuracy of results. Strong correlation was observed between the three methods: for medulloblastomas, r=1 (P<0.01) between FISH and array-CGH and r=0.92 (P<0.01) between qPCR and FISH/array-CGH. For neurocytomas, r=0.9 (P<0.01) between FISH and array-CGH and r=0.34/0.43 (P<0.01) between qPCR and FISH/array-CGH. Absolute qPCR assays possess high precision compared to other conventional methods and can be used for accurate and quickness detection of MYCN status (low-level gene gain and amplification).

The expression of BIRC5 is correlated with loss of specific chromosomal regions in breast carcinomas

Expression of BIRC5 (survivin), a member of the inhibitor of apoptosis protein (IAP) family, is elevated in fetal tissues and in various human cancers. Mechanisms up-regulating BIRC5 in cancer are poorly understood. Here, we show that overexpression of BIRC5 induces a high proliferation level in MCF-7 breast tumor cells. In a population of 191 breast carcinomas, BIRC5 expression is not affected by BIRC5 promoter polymorphism at -31, or BIRC5 gene copy number. However, a significant correlation was found between expression of demethylase (dMTase) and expression of BIRC5. In addition, among 13 chromosomal regions tested for allelic loss [loss of heterozygosity (LOH)], two regions close to D3S1478 and D6S264 were related to BIRC5 expression. In tumors with LOH at D3S1478 and/or D6S264, BIRC5 expression was significantly increased. These regions have been suggested to harbor tumor suppressor genes and/or common fragile sites that may play a role in increasing genetic instability. These results suggest that genes located near D3S1478 and D6S264 might work by inhibiting, directly or indirectly, BIRC5 expression and thus their loss leads to its up-regulation. In addition, BIRC5 expression may induce breast tumor proliferation by promoting genetic instability. This article contains Supplementary Material available at http://www.interscience.wiley.com/jpages/1045-2257/suppmat.

Erdheim-Chester disease: report of a case with PCR-based analysis of the expression of osteopontin and survivin in Xanthogranulomas following glucocorticoid treatment

Erdheim-Chester disease (ECD) is a form of non-Langerhans histiocytosis. In this report, we show a case of ECD presenting diabetes insipidus and multiple xanthogranulomas received glucocorticoid treatment over a year. During this period, xanthogranulomas improved in response to the glucocorticoid therapy. Furthermore, the expression of osteopontin in xanthogranulomatous tissues significantly decreased following the treatment. Our data show the expression of osteopontin in xanthogranulomatous tissues of ECD. Furthermore, the osteopontin mRNA decreased following glucocorticoid therapy with xanthogranuloma regression, suggesting that the expression level of osteopontin could be a marker of the disease activity of ECD.

Classification of neuroblastomas based on an analysis of the expression of genes related to prognosis

PURPOSE

To select the optimal treatment according to the grade of malignancy of neuroblastoma (NB), it is essential to accurately and rapidly identify genetic abnormalities associated with the prognosis. We have identified BIN1 and neuronatin beta as the novel prognosis-related genes for NBs. This study aims to assess the correlation between the combination of the expression level of prognosis-related genes and the outcome of NB.

METHODS

In 44 NB samples, the expression levels of TrkA, BIN1, and neuronatin beta were determined using quantitative reverse transcriptase-polymerase chain reaction; furthermore, the correlation between the expression of these genes' expression levels and the clinical progression of NB were assessed.

RESULTS

It was possible to classify 44 NBs into 4 groups regarding the grade of malignancy of NB. These 4 groups were all significantly associated with the clinical stages international NB staging system as well as the outcomes of the patients (P < .001, according to the trend test by Kruskal-Wallis exact test).

CONCLUSION

The combination of the expression levels of these genes using quantitative reverse transcriptase-polymerase chain reaction is indicated as the effective method to quickly and accurately evaluate the grade of malignancy of NBs.

Influence of 17q gain and promoter polymorphisms on mRNA expression of somatostatin receptor type 2 in neuroblastoma

BACKGROUND

Neuroblastoma, the most frequent solid extracranial tumor in children, is characterized by a wide spectrum of clinical behaviours. We previously reported that high expression of somatostatin receptor type-2 (sst2) mRNA is associated to increased overall and event free survival. Several genetic abnormalities are detected in neuroblastomas, frequently involving balanced and/or unbalanced gain on the long arm on chromosome 17, the same region containing sst2 gene.

METHODS

In this study we detected balanced and/or unbalanced 17q gain in 50 neuroblastomas. Since two polymorphisms in sst2 promoter (-57 C>G and -83 A>G) were previously described as responsible for an in vitro reduction of sst2 mRNA expression, promoter sequencing was also performed in the same samples. The results were compared to sst2 mRNA expression, measured by real-time RT-PCR.

RESULTS

The frequency of 17q gain (14/50 neuroblastomas) was significantly associated to sst2 mRNA over-expression (Fischer's exact test: p=0.0012). The sst2 expression was significant higher both in balance and unbalance 17q amplifications (ANOVA: p=0.04). Conversely, we found a reduction of sst2 mRNA in neuroblastomas with -57 C>G promoter polymorphism (ANOVA: p=0.03).

CONCLUSION

We highlighted that 17q gain and promoter polymorphisms can play a role into the regulation of sst2 expression in neuroblastomas.

Relationship of DDX1 and NAG gene amplification/overexpression to the prognosis of patients with MYCN-amplified neuroblastoma

PURPOSE

Amplification of the MYCN gene strongly correlates with advanced stage, rapid tumor progression and poor prognosis in neuroblastoma (NB). Several genes in the MYCN amplicon, including the DEAD box polypeptide 1 (DDX1) gene, and neuroblastoma-amplified gene (NAG gene), have been found to be frequently co-amplified with MYCN in NB. The aim of this study was to clarify the prognostic significance of the co-amplification or overexpression of DDX1 and NAG with MYCN.

PROCEDURE

The gene copy numbers and mRNA expression levels of MYCN, DDX1, and NAG in 113 primary NBs were determined by the real-time quantitative polymerase chain reaction or quantitative reverse transcriptase/polymerase chain reaction assay. The relationships between gene co-amplification/overexpression status and stage, age at diagnosis, and overall survival were analyzed.

RESULTS

For evaluating the frequency of DDX1 and NAG co-amplification, it proved appropriate to discriminate NBs with <40 copies of MYCN amplification from those with > or =40 copies of MYCN (DDX1, p = 0.00058; NAG, p = 0.0242, chi(2) for independence test). In patients with MYCN-amplified NB aged > or =18 months, those with tumor with enhanced DDX1 expression and low-NAG expression showed a significantly better outcome than those with low-DDX1 expression or enhanced NAG expression (p = 0.0245, log-rank test). None of the gene expression statuses had a significant relation to disease stage or survival for patients <18 months old. No relationship between any gene co-amplification status and disease stage, age at diagnosis, or overall survival was found.

CONCLUSIONS

Our findings suggest that there may be a subset of NB in which enhanced DDX1 and low-NAG expression consequent to DDX1 co-amplification without NAG amplification contributes to susceptibility to intensive therapy. A larger study using an age cut-off of 18 months will be required.

Rapid and accurate determination of MYCN copy number and 1p deletion in neuroblastoma by quantitative PCR

MYCN amplification and 1p36 deletion are adverse prognostic factors in neuroblastoma, and rapid accurate determination of MYCN amplification is essential for risk stratification. MYCN copy number and 1p36 deletion status were determined by fluorescence in situ hybridization (FISH) and real time PCR in a diagnostic pathology laboratory setting on 35 consecutive patients with neuroblastoma. The PCR technique was technically successful in all cases and results were generally available within 24 hr of biopsy. There was no discordance between FISH and PCR results. Real time PCR is a reliable, accurate, and simple technique that can be applied to small neuroblastoma biopsies allowing rapid diagnosis.

Biological diagnosis for neuroblastoma using the combination of highly sensitive analysis of prognostic factors

BACKGROUND/PURPOSE

To select the optimal treatment according to the degree of malignancy of neuroblastoma, it is essential to accurately and rapidly identify any genetic abnormalities associated with the prognosis. This study aims to assess the correlation between the combination of prognostic factors and the biologic findings of neuroblastoma using a highly sensitive analysis of prognostic factors.

METHODS

In 44 neuroblastoma primary samples, we determined the gene dosages of MYCN and Survivin (as the target of 17q gain) and the expression levels of MYCN, Survivin, and BIN1 using highly sensitive analysis (the quantitative polymerase chain reaction method); furthermore, we assessed the correlation between the combination of their prognostic factors and the biology of neuroblastoma.

RESULTS

The gene dosage of MYCN or Survivin was significantly associated with all known prognostic factors. The expression level of MYCN or Survivin was not significantly associated with any prognostic factors, whereas the expression level of BIN1 was significantly associated with 5 of 6 prognostic factors. Regarding the combination of MYCN amplification and 17q gain (the gene dosage of Survivin), and the low expression of BIN1, the rates of advanced stages (stage III or IV) were 100% for the cases with 3 factors, 63% for the cases with 2 factors, 42% for the cases with 1 factor, and 0% for the cases with null factor. Furthermore, the survival rates were 20% for the cases with 3 factors, 50% for the cases with 2 factors, 100% for the cases with 1 factor, and 100% for the cases with null factor.

CONCLUSION

The combination of gene dosages of MYCN and Survivin and the expression level of BIN1 using the quantitative polymerase chain reaction method was significantly correlated with the clinical stage and the patients' outcome. This combination of biologic factors may enhance the accuracy to the conventional criteria, but this would have to be shown in a much larger study that is adequately powered to detect such an advantage.

Cytoplasmic sequestration of cyclin D1 associated with cell cycle withdrawal of neuroblastoma cells

The regulation of D-type cyclin-dependent kinase activity is critical for neuronal differentiation and apoptosis. We recently showed that cyclin D1 is sequestered in the cytoplasm and that its nuclear localization induces apoptosis in postmitotic primary neurons. Here, we further investigated the role of the subcellular localization of cyclin D1 in cell cycle withdrawal during the differentiation of N1E-115 neuroblastoma cells. We show that cyclin D1 became predominantly cytoplasmic after differentiation. Targeting cyclin D1 expression to the nucleus induced phosphorylation of Rb and cdk2 kinase activity. Furthermore, cyclin D1 nuclear localization promoted differentiated N1E-115 cells to reenter the cell cycle, a process that was inhibited by p16(INK4a), a specific inhibitor of D-type cyclin activity. These results indicate that cytoplasmic sequestration of cyclin D1 plays a role in neuronal cell cycle withdrawal, and suggests that the abrogation of machinery involved in monitoring aberrant nuclear cyclin D1 activity contributes to neuronal tumorigenesis.

Downregulation of survivin by siRNA diminishes radioresistance of pancreatic cancer cells

BACKGROUND

Survivin is a member of the inhibitor of apoptosis protein family, which inhibits apoptosis and regulates cell division. Survivin is expressed by the majority of human cancers, including pancreatic adenocarcinoma. We have reported that its expression is correlated with shorter survival of pancreatic cancer patients, so regulation of this molecule could be a new strategy for fighting pancreatic cancer.

METHODS

In 3 pancreatic cancer cell lines (AsPC-1, SUIT-2, and Panc-1), survivin promoter activity was determined by the luciferase reporter assay, and survivin messenger RNA (mRNA) expression was examined by quantitative reverse transcriptase-polymerase chain reaction. The dose-dependent cytotoxity of radiation was also assessed, while caspase-3 activity and induction of DNA fragmentation were evaluated. Furthermore, the effect of silencing or nonsilencing short interfering RNA (siRNA) expression plasmids directed against the survivin gene on AsPC-1 cells, the most radioresistant cell line, was evaluated.

RESULTS

Pancreatic cancer cell lines expressed varying levels of survivin mRNA in association with transcriptional activity of the survivin promoter. Both survivin promoter activity and mRNA expression were correlated with tumor cell radiosensitivity. Radiation significantly increased survivin promoter activity and survivin mRNA expression in all cell lines. Radiation induced a significant increase in caspase-3 activity and DNA fragmentation in AsPC-1 cells. After silencing siRNA treatment of AsPC-1 cells (AS-S cells), there was a significant decrease in survivin mRNA expression and increase in caspase-3 activity, compared with the effect of nonsilencing scramble siRNA on AsPC-1 cells (AS-NS cells). AS-S cells were more radiosensitive than AS-NS cells. Radiation induced higher caspase-3 activity and more DNA fragmentation in AS-S cells, compared with AS-NS cells.

CONCLUSIONS

Survivin may play an important role as 1 of the radioresistance factors. Downregulation of survivin by siRNA can diminish the radioresistance of pancreatic cancer cells, so combined therapy with survivin inhibition and radiation may be useful for the treatment of pancreatic cancer.

Significance of survivin mRNA expression in prognosis of neuroblastoma

Neuroblastoma (NB) is the most common malignant solid tumor in childhood, and among all childhood malignancies is second in prevalence only to leukemia. In NB we need to both make an accurate diagnosis and rapidly analyze the expression of genetic prognostic factors such as MYCN, H-ras, and trkA. Moreover, it has recently become important to analyze the expression of survivin mRNA, a member of the inhibitor of apoptosis protein family. Expression of the survivin gene is related to tumorigenesis and inhibition of apoptosis in some malignant tumors. We investigated its expression by reverse transcription-polymerase chain reaction (RT-PCR) in NB cell lines (SK-N-SH, NB-39, and IMR-32), two normal blood cell samples, and 13 clinical NB tumor samples. All three NB cell lines had high levels of mRNA expression for this gene, but normal blood cells had no expression. We detected expression of survivin mRNA in 7 of the 13 NB tumor samples (54%). Two NB patients were in stage I disease, 6 in stage II, and 5 in stage IV(A). Quantitative analysis by RT-PCR revealed that the ratio between survivin mRNA and human glyceraldehyde-3-phosphate dehydrogenase (h-GAPDH) mRNA was very low in stages I and II (0-0.017). In contrast, in advanced NBs (stage IV(A)) the ratio was much higher (0-0.050). The prognoses of the three patients in the advanced stage who had high ratios of expression were poor. A high level of expression of survivin mRNA indicates a high grade of malignancy, high likelihood of recurrence, and poor prognosis.

VEGF-mediated survivin expression in neuroblastoma cells

BACKGROUND

Vascular endothelial growth factor (VEGF) up-regulates a number of cellular survival signals in endothelial cells. We hypothesize that VEGF will up-regulate survivin, a member of the IAP family of anti-apoptotic proteins, via the PI3K/Akt cell signaling pathway in human neuroblastoma cells.

MATERIALS AND METHODS

IMR-32 human neuroblastoma cells are cultured with VEGF at varying times and in escalating doses. A specific inhibitor of PI3-kinase, LY294002, is used to block Akt phosphorylation. Immunoblot is used to measure protein expression, and Hoechst staining is used to detect apoptosis.

RESULTS

Stimulation of IMR-32 neuroblastoma cells with VEGF results in an increase in survivin protein expression in both a dose- and a time-dependent fashion. Akt phosphorylation is also increased after stimulation with exogenous VEGF. Blockade of Akt phosphorylation with LY294002 abrogates the effects of VEGF upon survivin and phosphorylated Akt protein expression.

CONCLUSIONS

VEGF has been shown to up-regulate a number of survival signals in endothelial cells. We have found that exposure of human neuroblastoma cells to exogenous VEGF results in an increased expression of survivin protein and phosphorylated Akt, and inhibition of PI3-kinase abrogates those effects. It appears that VEGF is important for promotion of neuroblastoma cellular survival through the up-regulation of survival proteins, and not only through its angiogenic properties.

Lack of prognostic significance of survivin, survivin-deltaEx3, survivin-2B, galectin-3, bag-1, bax-alpha and MRP-1 mRNAs in breast cancer

The expression of transcripts for anti-apoptotic (survivin, survivin-deltaEx3, survivin-2B, galectin-3, bag-1 and bcl-2) and pro-apoptotic (bax-alpha) genes, and for multiple drug resistance related protein-1 (MRP-1) gene were investigated, using RT-PCR, in 106 breast tumour biopsies. Normal breast tissue was also analysed for comparative purposes. Overall, survivin, survivin-deltaEx3, survivin-2B, bcl-2, bag-1, galectin-3, bax-alpha and MRP-1 mRNAs were detected in 68, 54.7, 9.4, 78.4, 80.9, 98.9, 97.8 and 72.8%, respectively, of tumour specimens. Uniquely among the mRNAs analysed, the expression of bcl-2 correlated significantly with disease outcome, with bcl-2 expression indicative of favourable outcome in terms of both relapse-free survival and overall survival. This suggests that bcl-2 mRNA expression may be a key prognostic marker for breast cancer and that routine analysis of expression of this transcript should be considered. The results from this study suggest, however, that the expression of survivin, survivin-deltaEx3, survivin-2B, bag-1, galectin-3, bax-alpha and MRP-1 mRNAs cannot be considered as prognostic indicators of disease outcome for patients with breast cancer.

Clinical significance of a highly sensitive analysis for gene dosage and the expression level of MYCN in neuroblastoma

BACKGROUND

The amplification of the MYCN gene is one of the most powerful adverse prognosis factors in neuroblastoma, but the clinical significance of an enhanced expression of MYCN remains controversial. To reassess the clinical implications of MYCN amplification and expression in neuroblastoma, the status of amplification and the expression level of the MYCN gene of primary neuroblastoma samples were analyzed using highly sensitive analyses.

METHODS

Using a quantitative polymerase chain reaction (PCR) method (TaqMan), the gene dosages (MYCN/p53) of 66 primary neuroblastoma samples were determined. In all 66 samples, the status of MYCN amplification has been determined previously by the Southern blotting method. Of the 54 samples with a single copy of MYCN based on the Southern blotting method, 23 samples were analyzed for MYCN amplification using the fluorescence in situ hybridization (FISH) method. The expression levels (MYCN/GAPDH) of 56 samples were determined by a quantitative reverse transcriptase (RT)-PCR method.

RESULTS

Of the 54 samples with a single copy of MYCN based on the Southern blotting method, 46 samples showed MYCN gene dosages of less than 2.0, whereas the remaining 8 samples with dosages of more than 2.0 were tumors from patients with advanced-stage disease. The results of FISH supported the fact that these 8 samples contained a small number of MYCN-amplified cells. The cases of MYCN gene dosages of more than 2.0 were significantly associated with all other unfavorable prognostic factors (an age of >1 year at diagnosis [P <.0001], nonmass screening [P =.0003], advanced stage [P <.0001], diploid or tetraploid [P <.0001], and a Shimada unfavorable histology [P <.0001]). MYCN gene dosages of more than 2.0 were significantly associated with a high expression of MYCN (P =.0459). However, the expression level of MYCN was not significantly associated with any other prognostic factors.

CONCLUSIONS

Quantitative PCR may thus be a useful modality for performing a highly sensitive and accurate assessment of the amplification and expression levels of the MYCN gene. In particular, the combination of the quantitative PCR system and the FISH method is considered to be a highly effective method for evaluating the status of MYCN amplification. In this highly sensitive analysis, MYCN amplification (MYCN/p53 > or = 2.0) was reconfirmed to be a strongly unfavorable factor, whereas the expression level of MYCN does not appear to be an independently significant prognosis factor.

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.

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.

Dual expression of CD80 and CD86 produces a tumor vaccine superior to single expression of either molecule

A murine model for neuroblastoma, Neuro-2a (N2a), was used to establish a model tumor vaccine. An aggressive subclone of N2a and the less aggressive parental line were transfected with CD80, CD86, or both molecules and stable lines were established. The less aggressive N2a expressing either CD80 or CD86 induced anti-tumor immunity. In contrast, dual expression of CD80 and CD86 was required to initiate a protective anti-tumor immune response against the aggressive subclone. Control of tumor growth was dependent on CD8+ lymphocytes that infiltrated dual-expressing (CD80 and CD86) lesions. These tumor-infiltrating lymphocytes (TIL) exhibited a non-classical mechanism of tumor cell lysis that may require both the up-regulation of cell surface molecules on the tumor and the subsequent lytic activity normally associated with CD8+ TIL. Although Fas was up-regulated by the tumor in the presence of IFN-gamma, N2a and transfected N2a cell lines were not sensitive to Fas-mediated lysis.

High level amplification of N-MYC is not associated with adverse histology or outcome in primary retinoblastoma tumours

Twenty-five primary retinoblastoma tumours were analysed by real-time quantitative polymerase chain reaction to determine the genomic copy number of the N-MYC gene (2p24) relative to the copy number for REL, B2M, ALB, AF10 and MLL. Twenty-one of these tumours were shown by Comparative Genomic Hybridization to contain variable copy number increases of chromosomal material mapping to 2p. High level amplification (>30-fold) of N-MYC was found in three tumours, none of which showed adverse histological features and all patients are surviving at between 54 and 108 months post enucleation. Furthermore, the three tumours associated with metastasis and adverse patient outcome showed normal N-MYC copy number. Although high level amplification of N-MYC is an unfavourable prognostic indicator in neuroblastoma, these data show no evidence of a correlation between amplification of N-MYC and adverse outcome in retinoblastoma.

Quantification of MYCN, DDX1, and NAG gene copy number in neuroblastoma using a real-time quantitative PCR assay

Amplification of the proto-oncogene MYCN is a strong adverse prognostic factor in neuroblastoma patients in all tumor stages. The status of the MYCN gene has become an important factor in clinical decision making and therapy stratification. Consequently, fast and accurate assessment of MYCN gene copy number is of the utmost importance and the use of two independent methods to determine MYCN status is recommended. For these reasons we have developed and evaluated a real-time quantitative PCR (Q-PCR) assay as an alternative for time-consuming Southern blot analysis (SB), and as a second independent technique in parallel with fluorescence in situ hybridization (FISH) analysis. Advantages of Q-PCR are a large dynamic range of quantification, no requirement for post-PCR sample handling and the need for very small amounts of starting material. The accuracy of the assay was illustrated by measurement of MYCN single gene copy changes in DNA samples of two patients with 2p deletion and duplication, respectively. Two different detection chemistries i.e., a sequence specific TaqMan probe and a generic DNA binding dye SYBR Green I were evaluated and shown to yield similar results. Also, two different calculation methods for copy number determination were used i.e., the kinetic method and the comparative C(T) method, and shown to be equivalent. In total, 175 neuroblastoma samples with known MYCN status, as determined by FISH and/or SB, were examined. Q-PCR data were highly concordant with FISH and SB data. In addition to MYCN copy number evaluation, DDX1 and NAG gene copy numbers were determined using a similar Q-PCR strategy. Survival analysis pointed out that DDX1 and/or NAG amplification has no additional adverse effect on prognosis.

Induction of apoptosis in cancer: new therapeutic opportunities

Autonomous cell proliferation is one of the hallmarks of cancer cells, driven by activated growth-promoting oncogenes. However, deregulated activation of these oncogenes also triggers apoptosis via multiple pathways. Among them, the ARF-p53 pathway appears to play a major role in mediating oncogene-induced apoptosis. Consequently, suppression of apoptosis by inactivation of p53 and other tumor suppressors is central to tumor development. These findings have broad implications in understanding cancer genetics and therapy. They help define the roles for oncogenes and tumor suppressor genes in tumorigenesis. Furthermore, the notion that cancer cells often carry specific defects in apoptotic pathways but are inherently sensitive to apoptosis as a result of deregulated proliferation, offers numerous opportunities for manipulating apoptosis in directions of clinical application.

Evaluation of genetic heterogeneity in neuroblastoma

BACKGROUND AND METHODS

The prognosis in neuroblastoma, which is the most common solid tumor in children, tends to vary greatly, and many studies have demonstrated both clinical and biological factors to be closely correlated with the outcome. In order to select the optimal treatment according to the degree of malignancy of neuroblastoma, it is essential to accurately and rapidly identify any genetic heterogeneity associated with the prognosis. We assessed the status of some genetic abnormalities (MYCN amplification, deletion of the short arm of chromosome 1, DNA ploidy, and a gain of the chromosome 17q region) associated with the prognosis using several molecular biological methods.

RESULTS AND CONCLUSIONS

The combination of several molecular biological techniques is thus considered to be useful for elucidating the degree of malignancy of neuroblastoma. In particular, diagnostic analyses based on a combination of the fluorescence in situ hybridization (FISH) method and the quantitative polymerase chain reaction (PCR) method may be considered to be the most effective methods for quickly and accurately evaluating any aberrations in the gene dosages associated with the patients' outcomes.

Clinical and biologic characteristics for recurring neuroblastoma at mass screening cases in Japan

BACKGROUND

It is said that most cases detected by neuroblastoma mass screening at 6 months of age tend to have a favorable clinical course after a surgical resection either with or without mild chemotherapy. However, a few cases have an unfavorable outcome. In the current study, the authors analyzed the clinical and biologic characteristics for recurring neuroblastoma in mass screening cases.

METHODS

In 245 cases detected through mass screening in the Kyushu area in Japan, the clinical data and biologic features (N-myc status, DNA ploidy, Shimada histology, neuron-specific enolase (NSE), ferritin) were investigated, whereas, in particular, the data for recurring cases also were analyzed.

RESULTS

Of 245 cases, 28 tumors had one or more biologically unfavorable prognostic factors, and 6 patients experienced recurrence. Three of the six patients with recurring disease underwent a complete resection of the primary tumor, whereas three cases had undergone an incomplete resection of the tumor. Regarding the initial chemotherapy, three cases received mild chemotherapy, two cases received no chemotherapy, and one case had high-dose multidrug chemotherapy. Regarding biologic prognostic factors, four of six cases with recurring disease had one or more unfavorable factors, whereas two cases had no unfavorable factors. Regarding the outcome after recurrence, four cases are CR, one case has a stable residual tumor, and one case died of disease with N-myc amplification.

CONCLUSIONS

Most neuroblastomas detected by mass screening at 6 months of age have biologically favorable factors. However, approximately 10% of the cases had one or more unfavorable factors and thus might have a higher risk of recurrence than the patients with no unfavorable factors. Conversely, some cases with recurring disease had no unfavorable factors; however, the reason for this is still unclear. A long-term follow-up for mass screening cases is important, and it also might be necessary to research the established biologic factors and identify other new prognostic factors.