Survivin: an inhibitor of apoptosis in pediatric cancer

Prognostic significance of survivin expression in pediatric ewing sarcoma

Survivin is an inhibitor of apoptosis protein that inhibits caspases and blocks cell death. It is undetectable in most normal adult tissues. High survivin expression has been detected in various tumors and has been correlated with therapy resistance and poor outcome. We conducted this study to examine survivin expression in pediatric Ewing sarcoma (ES) and evaluate its role in predicting clinical outcome. Formalin-fixed paraffin-embedded tumor tissues from 108 pediatric ES patients were examined by immunostaining with survivin rabbit monoclonal antibodies. Survivin was detected in tumor tissues of 72 (66.7%) patients. High expression (≥50%) was detected in 18 (16.7%) patients. High survivin expression was shown to be a significant univariate parameter for poorer overall (OS) and event free survival (EFS) with p value 0.033, and 0.037 respectively. It was confirmed as an independent factor in multivariate analysis for OS (p: 0.041; HR: 1.97 with 95% CI of 1.03-3.79) and EFS (p: 0.049; HR: 1.86 with 95% CI of 1.00-3.46). These results suggest that high survivin expression identifies a group of patients with poor prognosis and this may help to refine risk adapted treatment; however, this needs to be confirmed in prospective studies.

The role of survivin in the pathogenesis of endometriosis

INTRODUCTION

Endometriosis is a common, estrogen-dependent condition, defined as the presence of endometrial-like tissue outside of the uterus, associated with often chronic and inflammatory reaction. The association of endometriosis with cancer is unclear, although endometriosis and cancer present some molecular similarities. Survinin, encoded by the BIRC5 gene, is a protein that controls cell division, inhibits apoptosis and promotes angiogenesis. Here we aimed to summarize and to discuss the main findings of studies that addressed the involvement of survivin in the pathogenesis of endometriosis.

EVIDENCE ACQUISITION

We conducted a comprehensive retrieval from electronic databases, included the MEDLINE, EMBASE, with no restrictions to time span. We used the search terms endometriosis and survivin or BIRC5 and collected all relevant studies to explore the association between endometriosis and surviving expression.

EVIDENCE SYNTHESIS

A total of 21 studies included in the systematic review, comprising sample collected from 1263 women with endometriosis. Results showed the involvement of more than 60 genes and proteins evaluated in eutopic, ectopic, endometrial and ovarian endometriosis, as well as in several gynecological conditions compared to healthy controls.

CONCLUSIONS

The studies provided the basis for the involvement of survivin in the pathogenesis of the disease by several and independent pathways.

Toward early cancer detection: Focus on biosensing systems and biosensors for an anti-apoptotic protein survivin and survivin mRNA

The development of biosensors for cancer biomarkers has recently been expanding rapidly, offering promising biomedical applications of these sensors as highly sensitive, selective, and inexpensive bioanalytical tools that can provide alternative methodology to that afforded by the advanced hyphenated-instrumental techniques. In this review, we focus particularly on the detection of a member of the inhibitor of apoptosis proteins (IAP) family, protein survivin (Sur), a ubiquitous re-organizer of the cell life cycle with the ability to inhibit the apoptosis and induce an enhanced proliferation leading to the unimpeded cancer growth and metastasis. Herein, we critically evaluate the progress in the development of novel biosensing systems and biosensors for the detection of two survivin (Sur) biomarkers: the Sur protein and its messenger RNA (Sur mRNA), including immunosensors, electrochemical piezo- and impedance-sensors, electrochemi-luminescence biosensors, genosensors based on oligonucleotide molecular beacons (MBs) with fluorescent or electrochemical transduction, as well as the microfluidic and related analytical platforms based on solution chemistry. The in-situ applications of survivin biomarkers' detection technologies to equip nanocarriers of the controlled drug delivery systems with MB-based fluorescence imaging capability, apoptosis control, and mitigation of the acquired drug resistance are also presented and critically evaluated. Finally, we turn the attention to the application of biosensors for the analysis of Sur biomarkers in exosomes and circulating tumor cells for a non-invasive liquid biopsy. The prospect of a widespread screening for early cancers, based on inexpensive point-of-care testing using biosensors and multiplex biosensor arrays, as a means of reducing the high cancer fatality rate, is discussed.

Survivin rs9904341 polymorphism significantly increased the risk of cancer: evidence from an updated meta-analysis of case-control studies

AIMS

Survivin, a member of inhibitor of apoptosis protein family, is involved in the regulation of cell cycle and apoptosis. Several studies inspected the association between survivin polymorphisms and the risk of various cancers, but the findings remain controversial. We conducted a meta-analysis intending to certify the association between survivin polymorphisms and cancer risk.

METHODS

All analyses were achieved using RevMan 5.3 software and STATA 14.1 software. Eligible studies were collected by comprehensive literature searching Web of Science, PubMed, Scopus, and Google scholar databases. Pooled estimates of odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the overall impact of survivin polymorphisms on cancer risk.

RESULTS

The overall analysis indicates that survivin rs9904341 polymorphism significantly increased the risk of cancer in homozygous codominant (OR 1.41, 95% CI 1.19-1.68, p = 0.0001, CC vs GG), dominant (OR 1.22, 95% CI 1.07-1.40, p = 0.003, CG+CC vs GG), recessive (OR 1.34, 95% CI 1.18-1.52, p < 0.0001, CC vs CG+GG), and allele (OR 1.20, 95% CI 1.09-1.31, p = 0.0001, C vs G) inheritance models tested. Stratified based on ethnicity revealed that rs9904341 variant significantly increased the risk of cancer in the Asian population. The findings did not support an association between rs1042489, rs2071214, rs8073069, and rs17878467 polymorphisms and risk of cancer.

CONCLUSIONS

The current study suggests that the survivin rs9904341 polymorphism may be associated with the risk of cancer either overall or in the Asian population. However, further larger and well-designed studies are warranted to evaluate this association in detail.

Hairpin-Hairpin Molecular Beacon Interactions for Detection of Survivin mRNA in Malignant SW480 Cells

Cancer biomarkers offer unique prospects for the development of cancer diagnostics and therapy. One of such biomarkers, protein survivin (Sur), exhibits strong antiapoptotic and proliferation-enhancing properties and is heavily expressed in multiple cancers. Thus, it can be utilized to provide new modalities for modulating the cell-growth rate, essential for effective cancer treatment. Herein, we have focused on the development of a new survivin-based cancer detection platform for colorectal cancer cells SW480 using a turn-on fluorescence oligonucleotide molecular beacon (MB) probe, encoded to recognize Sur messenger RNA (mRNA). Contrary to the expectations, we have found that both the complementary target oligonucleotide strands as well as the single- and double-mismatch targets, instead of exhibiting the anticipated simple random conformations, preferentially formed secondary structure motifs by folding into small-loop hairpin structures. Such a conformation may interfere with, or even undermine, the biorecognition process. To gain better understanding of the interactions involved, we have replaced the classical Tyagi-Kramer model of interactions between a straight target oligonucleotide strand and a hairpin MB with a new model to account for the hairpin-hairpin interactions as the biorecognition principle. A detailed mechanism of these interactions has been proposed. Furthermore, in experimental work, we have demonstrated an efficient transfection of malignant SW480 cells with SurMB probes containing a fluorophore Joe (SurMB-Joe) using liposomal nanocarriers. The green emission from SurMB-Joe in transfected cancer cells, due to the hybridization of the SurMB-Joe loop with Sur mRNA hairpin target, corroborates Sur overexpression. On the other hand, healthy human-colon epithelial cells CCD 841 CoN show only negligible expression of survivin mRNA. These experiments provide the proof-of-concept for distinguishing between the cancer and normal cells by the proposed hairpin-hairpin interaction method. The single nucleotide polymorphism sensitivity and a low detection limit of 26 nM (S/N = 3σ) for complementary targets have been achieved.

Survivin as a novel target protein for reducing the proliferation of cancer cells

Survivin, also known as baculoviral inhibitor of apoptosis repeat-containing 5, is a novel member of the inhibitor of apoptosis protein family. Survivin is highly expressed in tumors and embryonic tissues and is associated with tumor cell differentiation, proliferation, invasion and metastasis; however, survivin is expressed at low levels in normal terminally differentiated adult tissues. Meanwhile, the expression level of survivin is also a negative prognostic factor for patients with cancer. These unique characteristics of survivin make it an exciting potential therapeutic target for cancer treatment. This review will discuss the biological characteristics of survivin and its potential use as a treatment target to reduce cancer cell proliferation.

Synergistic Antitumour Properties of viscumTT in Alveolar Rhabdomyosarcoma

Aqueous mistletoe extracts from the European mistletoe (Viscum album) contain mainly mistletoe lectins and viscotoxins as cytotoxic compounds. Lipophilic triterpene acids, which do not occur in conventional mistletoe preparations, were solubilised with β-cyclodextrins. The combination of an aqueous extract (viscum) and a triterpene-containing extract (TT) recreated a whole mistletoe extract (viscumTT). These extracts were tested on rhabdomyosarcoma in vitro, ex vivo, and in vivo with regard to anticancer effects. Viscum and viscumTT inhibited cell proliferation and induced apoptosis effectively in a dose-dependent manner in vitro and ex vivo, whereas TT showed only moderate inhibitory effects. viscumTT proved to be more effective than the single extracts and displayed a synergistic effect in vitro and a stronger effect in vivo. viscumTT induced apoptosis via the extrinsic and intrinsic pathways, evidenced by the loss of mitochondrial membrane potential and activation of CASP8 and CASP9. CASP10 inhibitor inhibited apoptosis effectively, emphasising the importance of CASP10 in viscumTT-induced apoptosis. Additionally, viscumTT changed the ratio of apoptosis-associated proteins by downregulation of antiapoptotic proteins such as XIAP and BIRC5, thus shifting the balance towards apoptosis. viscumTT effectively reduced tumour volume in patient-derived xenografts in vivo and may be considered a promising substance for rhabdomyosarcoma therapy.

The DNA methyltransferase inhibitor zebularine exerts antitumor effects and reveals BATF2 as a poor prognostic marker for childhood medulloblastoma

Medulloblastoma (MB) is the most common solid tumor among pediatric patients and corresponds to 20 % of all pediatric intracranial tumors in this age group. Its treatment currently involves significant side effects. Epigenetic changes such as DNA methylation may contribute to its development and progression. DNA methyltransferase (DNMT) inhibitors have shown promising anticancer effects. The agent Zebularine acts as an inhibitor of DNA methylation and shows low toxicity and high efficacy, being a promising adjuvant agent for anti-cancer chemotherapy. Several studies have reported its effects on different types of tumors; however, there are no studies reporting its effects on MB. We analyzed its potential anticancer effects in four pediatric MB cell lines. The treatment inhibited proliferation and clonogenicity, increased the apoptosis rate and the number of cells in the S phase (p < 0.05), as well as the expression of p53, p21, and Bax, and decreased cyclin A, Survivin and Bcl-2 proteins. In addition, the combination of zebularine with the chemotherapeutic agents vincristine and cisplatin resulted in synergism and antagonism, respectively. Zebularine also modulated the activation of the SHH pathway, reducing SMO and GLI1 levels and one of its targets, PTCH1, without changing SUFU levels. A microarray analysis revealed different pathways modulated by the drug, including the Toll-Like Receptor pathway and high levels of the BATF2 gene. The low expression of this gene was associated with a worse prognosis in MB. Taken together, these data suggest that Zebularine may be a potential drug for further in vivo studies of MB treatment.

Survivin as a therapeutic target in Sonic hedgehog-driven medulloblastoma

Medulloblastoma (MB) is a highly malignant brain tumor that occurs primarily in children. Although surgery, radiation and high-dose chemotherapy have led to increased survival, many MB patients still die from their disease, and patients who survive suffer severe long-term side effects as a consequence of treatment. Thus, more effective and less toxic therapies for MB are critically important. Development of such therapies depends in part on identification of genes that are necessary for growth and survival of tumor cells. Survivin is an inhibitor of apoptosis protein that regulates cell cycle progression and resistance to apoptosis, is frequently expressed in human MB and when expressed at high levels predicts poor clinical outcome. Therefore, we hypothesized that Survivin may have a critical role in growth and survival of MB cells and that targeting it may enhance MB therapy. Here we show that Survivin is overexpressed in tumors from patched (Ptch) mutant mice, a model of Sonic hedgehog (SHH)-driven MB. Genetic deletion of survivin in Ptch mutant tumor cells significantly inhibits proliferation and causes cell cycle arrest. Treatment with small-molecule antagonists of Survivin impairs proliferation and survival of both murine and human MB cells. Finally, Survivin antagonists impede growth of MB cells in vivo. These studies highlight the importance of Survivin in SHH-driven MB, and suggest that it may represent a novel therapeutic target in patients with this disease.

A phase I study of EZN-3042, a novel survivin messenger ribonucleic acid (mRNA) antagonist, administered in combination with chemotherapy in children with relapsed acute lymphoblastic leukemia (ALL): a report from the therapeutic advances in childhood leukemia and lymphoma (TACL) consortium

To address the therapeutic challenges in childhood relapsed ALL, a phase 1 study combining a survivin mRNA antagonist, EZN-3042, with reinduction chemotherapy was developed for pediatric patients with second or greater bone marrow relapses of B-lymphoblastic leukemia. EZN-3042 was administered as a single agent on days -5 and -2 and then in combination with a 4-drug reinduction platform on days 8, 15, 22, and 29. Toxicity and the biological activity of EZN-3042 were assessed. Six patients were enrolled at dose level 1 (EZN-3042 2.5 mg/kg/dose). Two dose-limiting toxicities were observed: 1 patient developed a grade 3 γ-glutamyl transferase elevation and another patient developed a grade 3 gastrointestinal bleeding. Downmodulation of survivin mRNA and protein were assessed after single-agent dosing and decreased expression was observed in 2 of 5 patients with sufficient material for analysis. Although some biological activity was observed, the combination of EZN-3042 with intensive reinduction chemotherapy was not tolerated at a dose that led to consistent downregulation of survivin expression. The trial was terminated following the completion of dose level 1, after further clinical development of this agent was halted.

Wnt inhibition leads to improved chemosensitivity in paediatric acute lymphoblastic leukaemia

While childhood acute lymphoblastic leukaemia (ALL) is now highly curable, the dismal prognosis for children who relapse warrants novel therapeutic approaches. Previously, using an integrated genomic analysis of matched diagnosis-relapse paired samples, we identified overactivation of the Wnt pathway as a possible mechanism of recurrence. To validate these findings and document whether Wnt inhibition may sensitize cells to chemotherapy, we analysed the expression of activated β-catenin (and its downstream target BIRC5) using multiparameter phosphoflow cytometry and tested the efficacy of a recently developed Wnt inhibitor, iCRT14, in ALL cell lines and patient samples. We observed increased activation of β-catenin at relapse in 6/10 patients. Furthermore, treatment of leukaemic cell lines with iCRT14 led to significant downregulation of Wnt target genes and combination with traditional chemotherapeutic drugs resulted in a synergistic decrease in viability as well as a significant increase in apoptotic cell death. Finally, pre-treatment of purified blasts from patients with relapsed leukaemia with the Wnt inhibitor followed by exposure to prednisolone, restored chemosensitivity in these cells. Our results demonstrate that overactivation of the Wnt pathway may contribute to chemoresistance in relapsed childhood ALL and that Wnt-inhibition may be a promising therapeutic approach.

Survivin beyond physiology: orchestration of multistep carcinogenesis and therapeutic potentials

Survivin, a member of the inhibitor of apoptosis protein family, has been associated with protection from cell apoptosis and regulation of mitosis. Survivin exhibits low to undetectable expression in most finally differentiated adult tissues but is abundantly over-expressed in almost all cancers. The aberrant high expression of survivin in cancers is associated with advanced disease, increased rate of tumor recurrence, abbreviated overall survival and resistance to chemo- and radio- therapy. Survivin touches nearly every aspect of cancer and is involved in the initiation, maintenance and development of tumor. Therefore, its significance in cancer dictates the pursuit for anti-survivin cancer therapies.

Reevesioside F induces potent and efficient anti-proliferative and apoptotic activities through Na⁺/K⁺-ATPase α3 subunit-involved mitochondrial stress and amplification of caspase cascades

Reevesioside F, isolated from Reevesia formosana, induced anti-proliferative activity that was highly correlated with the expression of Na⁺/K⁺-ATPase α₃ subunit in several cell lines, including human leukemia HL-60 and Jurkat cells, and some other cell lines. Knockdown of α₃ subunit significantly inhibited cell apoptosis suggesting a crucial role of the α₃ subunit. Reevesioside F induced a rapid down-regulation of survivin protein, followed by release of cytochrome c from mitochondria and loss of mitochondrial membrane potential (ΔΨm). Further examination demonstrated the mitochondrial damage in leukemic cells through Mcl-1 down-regulation, Noxa up-regulation and an increase of the formation of truncated Bid, tBim and a 23-kDa cleaved Bcl-2 fragment. Furthermore, reevesioside F induced an increase of mitochondria-associated acetyl α-tubulin that may also contribute to apoptosis. The caspase cascade was profoundly activated by reevesioside F. Notably, the specific caspase-3 inhibitor z-DEVD-fmk significantly blunted reevesioside F-induced loss of ΔΨm and apoptosis, suggesting that caspase-3 activation may further amplify mitochondrial damage and apoptotic signaling cascade. In spite of being a cardiac glycoside, reevesioside F did not increase the intracellular Ca²⁺ levels. Moreover, CGP-37157 which blocked Na⁺/Ca²⁺ exchanger on plasma membrane and mitochondria did not modify reevesioside F-mediated effect. In summary, the data suggest that reevesioside F induces apoptosis through the down-regulation of survivin and Mcl-1, and the formation of pro-apoptotic fragments from Bcl-2 family members. The loss of ΔΨm and mitochondrial damage are responsible for the activation of caspases. Moreover, the amplification of caspase-3-mediated signaling pathway contributes largely to the execution of apoptosis in leukemic cells.

Histone deacetylase inhibition induces apoptosis and autophagy in human neuroblastoma cells

Neuroblastoma (NB) is the most common solid extracranial tumor in children. Here we showed that trichostatin A, a histone deacetylase inhibitor (HDACi), decreases cell viability in three NB cell lines of different phenotypes. The treatment leads to G2/M-phase arrest, apoptosis and autophagy. Autophagy induction accompanies apoptosis in the most proliferative, N-Myc overexpressing cells. In contrast, autophagy precedes apoptosis and acts as a protective mechanism in the less proliferative, non-N-Myc overexpressing cells. Therefore, the autophagy induction is a relevant event in the NB response to HDACis, and it should be considered in the design of new treatments for this malignancy.

Targeted BIRC5 silencing using YM155 causes cell death in neuroblastoma cells with low ABCB1 expression

The BIRC5 (Survivin) gene is located at chromosome 17q in the region that is frequently gained in high risk neuroblastoma. BIRC5 is strongly over expressed in neuroblastoma tumour samples, which correlates to a poor prognosis. We recently validated BIRC5 as a potential therapeutic target by showing that targeted knock down with shRNA's triggers an apoptotic response through mitotic catastrophe. We now tested YM155, a novel small molecule selective BIRC5 suppressant that is currently in phase I/II clinical trials. Drug response curves showed IC50 values in the low nM range (median: 35 nM, range: 0.5-> 10,000 nM) in a panel of 23 neuroblastoma cell lines and four TIC-lines, which resulted from an apoptotic response. Nine out of 23 cell lines were relatively resistant to YM155 with IC50 values > 200 nM, although in the same cells shRNA mediated knock down of BIRC5 caused massive apoptosis. Analysis of differentially expressed genes between five most sensitive and five most resistant cell lines using Affymetrix mRNA expression data revealed ABCB1 (MDR1) as the most predictive gene for resistance to YM155. Inhibition of the multi-drug resistance pump ABCB1 with cyclosporine or knockdown with shRNA prior to treatment with YM155 demonstrated that cell lines with ABCB1 expression became 27-695 times more sensitive to YM155 treatment. We conclude that most neuroblastoma cell lines are sensitive to YM155 in the low nM range and that resistant cells can be sensitised by ABCB1 inhibitors. Therefore YM155 is a promising novel compound for treatment of neuroblastoma with low ABCB1 expression.

Knockdown of survivin (BIRC5) causes apoptosis in neuroblastoma via mitotic catastrophe

BIRC5 (survivin) is one of the genes located on chromosome arm 17q in the region that is often gained in neuroblastoma. BIRC5 is a protein in the intrinsic apoptotic pathway that interacts with XIAP and DIABLO leading to caspase-3 and caspase-9 inactivation. BIRC5 is also involved in stabilizing the microtubule-kinetochore dynamics. Based on the Affymetrix mRNA expression data, we here show that BIRC5 expression is strongly upregulated in neuroblastoma compared with normal tissues, adult malignancies, and non-malignant fetal adrenal neuroblasts. The over-expression of BIRC5 correlates with an unfavorable prognosis independent of the presence of 17q gain. Silencing of BIRC5 in neuroblastoma cell lines by various antisense molecules resulted in massive apoptosis as measured by PARP cleavage and FACS analysis. As both the intrinsic apoptotic pathway and the chromosomal passenger complex can be therapeutically targeted, we investigated in which of them BIRC5 exerted its essential anti-apoptotic role. Immunofluorescence analysis of neuroblastoma cells after BIRC5 silencing showed formation of multinucleated cells indicating mitotic catastrophe, which leads to apoptosis via P53 and CASP2. We show that BIRC5 silencing indeed resulted in activation of P53 and we could rescue apoptosis by CASP2 inhibition. We conclude that BIRC5 stabilizes the microtubules in the chromosomal passenger complex in neuroblastoma and that the apoptotic response results from mitotic catastrophe, which makes BIRC5 an interesting target for therapy.

Endogenous knockdown of survivin improves chemotherapeutic response in ALL models

Although the cure rate of newly diagnosed acute lymphoblastic leukemia (ALL) has improved over the past four decades, the outcome for patients who relapse remains poor. New therapies are needed for these patients. Our previous global gene expression analysis in a series of paired diagnosis-relapse pediatric patient samples revealed that the antiapoptotic gene survivin was consistently upregulated upon disease relapse. In this study, we demonstrate a link between survivin expression and drug resistance and test the efficacy of a novel antisense agent in promoting apoptosis when combined with chemotherapy. Gene-silencing experiments targeting survivin mRNA using either short-hairpin RNA (shRNA) or a locked antisense oligonucleotide (LNA-ON) specifically reduced gene expression and induced apoptosis in leukemia cell lines. When used in combination with chemotherapy, the survivin shRNA and LNA-ON potentiated the chemotherapeutic antileukemia effect. Moreover, in a mouse primary xenograft model of relapse ALL, the survivin LNA-ON decreased survivin expression in a subset of animals, and produced a statistically significant decrease in tumor progression. Taken together, these findings suggest that targeting endogenous levels of survivin mRNA by LNA-ON methods may augment the response to standard chemotherapy by sensitizing otherwise resistant tumor cells to chemotherapy.

Overexpression of survivin initiates hematologic malignancies in vivo

Survivin is an inhibitor of apoptosis protein family member that has an essential role in cellular proliferation as a component of the chromosome passenger complex. Survivin is highly expressed in embryos and in proliferating adult tissues, but it is not expressed in most differentiated cells. During tumorigenesis, however, survivin expression is dramatically upregulated. Although many studies have shown that survivin is required for cancer cells, the extent to which survivin contributes to the initiation of tumors is unknown. Here we show that transgenic mice that overexpress survivin in hematopoietic cells are at an increased risk of hematologic tumors. In examining how survivin might contribute to tumorigenesis, we observed that hematopoietic cells engineered to overexpress survivin are less susceptible to apoptosis. We conclude that survivin may promote tumorigenesis by imparting a survival advantage to cells that acquire additional genetic lesions.

Enhanced tumor suppression in vitro and in vivo by co-expression of survivin-specific siRNA and wild-type p53 protein

The development of malignant prostate cancer involves multiple genetic alterations. For example, alterations in both survivin and p53 are reported to have crucial roles in prostate cancer progression. However, little is known regarding the interrelationships between p53 and survivin in prostate cancer. Our data demonstrate that the expression of survivin is inversely correlated with that of wtp53 protein (r(s)=0.548) in prostate cancer and in normal prostate tissues. We have developed a therapeutic strategy, in which two antitumor factors, small interfering RNA-survivin and p53 protein, are co-expressed from the same plasmid, and have examined their effects on the growth of PC3, an androgen-independent prostate cancer cell line. When p53 was expressed along with a survivin-specific short hairpin RNA (shRNA), tumor cell proliferation was significantly suppressed and apoptosis occurred. In addition, this combination also abrogated the expression of downstream target molecules such as cyclin-dependent kinase 4 and c-Myc, while enhancing the expression of GRIM19. These changes in gene expression occurred distinctly in the presence of survivin-shRNA/wtp53 compared with control or single treatment groups. Intratumoral injection of the co-expressed construct inhibited the growth and survival of tumor xenografts in a nude mouse model. These studies revealed evidence of an interaction between p53 and survivin proteins plus a complex signaling network operating downstream of the wtp53-survivin pathway that actively controls tumor cell proliferation, survival and apoptosis.

Mice lacking dystrophin or alpha sarcoglycan spontaneously develop embryonal rhabdomyosarcoma with cancer-associated p53 mutations and alternatively spliced or mutant Mdm2 transcripts

Altered expression of proteins in the dystrophin-associated glycoprotein complex results in muscular dystrophy and has more recently been implicated in a number of forms of cancer. Here we show that loss of either of two members of this complex, dystrophin in mdx mice or alpha sarcoglycan in Sgca(-/-) mice, results in the spontaneous development of muscle-derived embryonal rhabdomyosarcoma (RMS) after 1 year of age. Many mdx and Sgca(-/-) tumors showed increased expression of insulin-like growth factor 2, retinoblastoma protein, and phosphorylated Akt and decreased expression of phosphatase and tensin homolog gene, much as is found in a human RMS. Further, all mdx and Sgca(-/-) RMS analyzed had increased expression of p53 and murine double minute (mdm)2 protein and contained missense p53 mutations previously identified in human cancers. The mdx RMS also contained missense mutations in Mdm2 or alternatively spliced Mdm2 transcripts that lacked an exon encoding a portion of the p53-binding domain. No Pax3:Fkhr or Pax7:Fkhr translocation mRNA products were evident in any tumor. Expression of natively glycosylated alpha dystroglycan and alpha sarcoglycan was reduced in mdx RMS, whereas dystrophin expression was absent in almost all human RMS, both for embryonal and alveolar RMS subtypes. These studies show that absence of members of the dystrophin-associated glycoprotein complex constitutes a permissive environment for spontaneous development of embryonal RMS associated with mutation of p53 and mutation or altered splicing of Mdm2.

Tumor antigen precursor protein profiles of adult and pediatric brain tumors identify potential targets for immunotherapy

OBJECTIVES

We evaluated and compared tumor antigen precursor protein (TAPP) profiles in adult and pediatric brain tumors of 31 genes related to tumor associated antigens (TAA) for possible use in immunotherapy. Antigens were selected based on their potential to stimulate T cell responses against tumors of neuroectodermal origin.

METHODS

Thirty-seven brain tumor specimens from 11 adult and 26 pediatric patients were analyzed by quantitative real-time PCR for the relative expression of 31 TAPP mRNAs. The age range of adults (4F:7M) was 27-77 years (median 51.5 +/- 14.5 years) and for pediatrics (12F:14M) was 0.9-19 years (median 8.3 +/- 5.5 years). Histological diagnoses consisted of 16 glioblastomas, 4 low grade astrocytomas, 10 juvenile pilocytic astrocytomas, and 7 ependymomas.

RESULTS

The adult gliomas expressed 94% (29 of 31) of the TAPP mRNAs evaluated compared with pediatric brain tumors that expressed 55-74% of the TAPP mRNAs, dependent on tumor histological subtype. Four types of TAPP expression patterns were observed: (1) equal expression among adult and pediatric cases, (2) greater expression in adult than pediatric cases, (3) expression restricted to adult GBM and (4) a random distribution. The pediatric brain tumors lacked expression of some genes associated with engendering tumor survival, such as hTert and Survivin.

CONCLUSIONS

The potential TAA targets identified from the TAPP profiles of 31 genes associated with adult and pediatric brain tumors may help investigators select specific target antigens for developing dendritic cell- or peptide-based vaccines or T cell-based immunotherapeutic approaches against brain tumors.

Initial Patient Characteristics Can Predict Pattern and Risk of Relapse in Localized Rhabdomyosarcoma

Purpose

Evaluation of primary tumor-, treatment-, and patient-related factors predicting relapse pattern, risk, and survival after relapse with the aim to design a risk-adapted, tumor-directed surveillance program for patients with localized rhabdomyosarcoma (RMS).

Patients and Methods

One thousand one hundred sixty-four patients with nonmetastatic RMS achieved complete remission at the end of multimodal therapy in the consecutive trials of the Cooperative Weichteilsarkom Studiengruppe (CWS)-81, CWS-86, CWS-91, and CWS-96 between 1980 and 2002 (median follow-up, 5 years). Three hundred thirty-seven of these individuals developed either locoregional, metastatic, or combined relapses. Predictive factors for relapse, its pattern, and postrelapse survival were analyzed.

Results

Age, histology, tumor size, tumor site, postsurgical stage, and omission of radiotherapy were identified as factors associated with an increased relapse risk in multivariate analyses. Relapse rates did not differ among the CWS trials. Median time to relapse was 1.43 years from first diagnosis (range, 0.13 to 13.5 years). There were 217 locoregional, 72 metastatic, and 48 combined recurrences. Only two patients developed metastases more than 4 years after diagnosis, and both had combined recurrences. Five-year postrelapse survival was 24%. Patient subsets with consistent relapse pattern, risk, and postrelapse survival rates were identified on the basis of histologic subtype and tumor size.

Conclusion

Initial patient and tumor characteristics predict pattern and risk of relapse and also correlate with postrelapse survival probabilities. In localized RMS, tumor-directed follow-up should focus on the primary site. Screening for metastatic relapse may not be necessary more than 4 years after diagnosis. The identification of subgroups with distinctive pattern and risk of relapse may be used to develop risk-adapted, tumor-directed guidance for detection of recurrent disease in localized RMS.