Histopathological evaluation of apoptosis in cancer

Antiproliferative and Proapoptotic Effects of Labisia pumila Ethanol Extract and Its Active Fraction in Human Melanoma HM3KO Cells

The present study was to determine the anticancer potential of Labisia pumila in in vitro models. Results from the study revealed that ethanol extract of L. pumila was more cytotoxic against HM3KO cells while having reduced effects on nonmalignant cells as compared to aqueous and hexane extracts. Thus, ethanol extract was selected to be further separated by using the bioassay-guided fractionation method to give an active fraction, SF2Lp. Results obtained from the flow cytometry analysis showed that SF2Lp was able to arrest the HM3KO cell cycle at the G1 phase, while morphological findings from AO-EB nuclear staining assays along with the Apoptotic Index confirmed the induction of apoptosis by SF2Lp in HM3KO cells. Results from the mechanistic study further revealed that SF2Lp treatment was able to concurrently increase the expression level of p53 and pro-apoptotic protein Bax and also reduce the expression level of anti-apoptotic protein BCl-2 in HM3KO cells, directly contributing to the increase in Bax/Bcl-2 ratio. These findings, therefore, suggested that L. pumila was able to inhibit HM3KO cell growth possibly by arresting the cell cycle at G1 phase and inducing apoptosis in HM3KO cells via the up- and down-regulation of Bax/Bcl-2 protein, mediated through a p53-dependent pathway.

COMPARISON OF SPARSE CODING AND KERNEL METHODS FOR HISTOPATHOLOGICAL CLASSIFICATION OF GLIOBASTOMA MULTIFORME

This paper compares performance of redundant representation and sparse coding against classical kernel methods for classifying histological sections. Sparse coding has been proven to be an effective technique for restoration, and has recently been extended to classification. The main issue with classification of histology sections is inherent heterogeneity as a result of technical and biological variations. Technical variations originate from sample preparation, fixation, and staining from multiple laboratories, where biological variations originate from tissue content. Image patches are represented with invariant features at local and global scales, where local refers to responses measured with Laplacian of Gaussians, and global refers to measurements in the color space. Experiments are designed to learn dictionaries, through sparse coding, and to train classifiers through kernel methods with normal, necorotic, apoptotic, and tumor with with characteristics of high cellularity. Two different kernel methods of support vector machine (SVM) and kernel discriminant analysis (KDA) are used for comparative analysis. Preliminary investigation on histological samples of Glioblastoma multiforme (GBM) indicates that kernel methods perform as good if not better than sparse coding with redundant representation.

[Effect of low doses of x-ray irradiation on the liver detoxication system in rats with transplanted Guerin's carcinoma]

The activity of detoxication enzymes in liver microsomal fraction of preliminary radiation-exposed rats was investigated. It was shown that preliminary organism exposure to radiation reduced cytochrome P450 and glutathione-S-transferase activity in liver microsomal fraction in the latent and logarithmic phases of oncogenesis compared with the unirradiated rats with tumor. Low level of cytochrome P450 activity can be caused by transition of microsomal cytochrome P450 in P420 inactive form. The preliminary radiation does not influence the enzyme activity of liver cytochrome P450 and glutathione-S-transferase on terminal stages of Guerin's carcinoma growth.

Apoptosis-related deregulation of proteolytic activities and high serum levels of circulating nucleosomes and DNA in blood correlate with breast cancer progression

Background

As cell-free circulating DNA exists predominantly as mono- and oligonucleosomes, the focus of the current study was to examine the interplay of circulating nucleosomes, DNA, proteases and caspases in blood of patients with benign and malignant breast diseases.

Methods

The concentrations of cell-free DNA and nucleosomes as well as the protease and caspase activities were measured in serum of patients with benign breast disease (n = 20), primary breast cancer (M0, n = 31), metastatic breast cancer (M1, n = 32), and healthy individuals (n = 28) by PicoGreen, Cell Death Detection ELISA, Protease Fluorescent Detection Kit and Caspase-Glo^®3/7 Assay, respectively.

Results

Patients with benign and malignant tumors had significantly higher levels of circulating nucleic acids in their blood than healthy individuals (p = 0.001, p = 0.0001), whereas these levels could not discriminate between benign and malignant lesions. Our analyses of all serum samples revealed significant correlations of circulating nucleosome with DNA concentrations (p = 0.001), nucleosome concentrations with caspase activities (p = 0.008), and caspase with protease activities (p = 0.0001). High serum levels of protease and caspase activities associated with advanced tumor stages (p = 0.009). Patients with lymph node-positive breast cancer had significantly higher nucleosome levels in their blood than node-negative patients (p = 0.004). The presence of distant metastases associated with a significant increase in serum nucleosome (p = 0.01) and DNA levels (p = 0.04), and protease activities (p = 0.008).

Conclusion

Our findings demonstrate that high circulating nucleic acid concentrations in blood are no indicators of a malignant breast tumor. However, the observed changes in apoptosis-related deregulation of proteolytic activities along with the elevated serum levels of nucleosomes and DNA in blood are linked to breast cancer progression.

Novel oligomeric proanthocyanidin derivatives interact with membrane androgen sites and induce regression of hormone-independent prostate cancer

Prostate cancer is the most common malignancy among men in Western societies, and current therapeutic approaches are evolving to manage growth, recurrence, and mortality neoplasia. Membrane androgen receptors (mARs) have been characterized in human prostate cancer, being preferentially expressed in tumor rather than benign gland areas. Furthermore, mAR agonists (protein-conjugated testosterone) decrease in vitro prostate cancer cell growth and induce apoptosis, whereas in vivo they regress growth of tumor xenografts alone or in combination with taxane drugs. In this respect, targeting mARs might be a novel therapeutic approach in prostate cancer. In our search for new small-molecule ligands of mAR, we report that flavanol dimers B1-B4 (oligomeric procyanidins) decrease in vitro growth of the androgen-sensitive (LnCaP) and androgen-resistant (DU145) human prostate cancer cell lines in the following order: B3 = B4 > B2 ≫ B1 (LnCaP) and B2 ≫ B3 = B4 ≫ B1 (DU145). Some of these analogs were previously shown to trigger signaling cascades similar to testosterone-bovine serum albumin (BSA) conjugate. Galloylation does not confer an additional advantage; however, oleylation increases the dimers' antiproliferative potency by a factor of 100. In addition, we report that B2, oleylated or not, displaces testosterone from mARs with an IC(50) value at the nanomolar range and induces DU145 tumor xenograft regression by 50% (testosterone-BSA 40%). In this respect, oleylated B2 is a potent small-molecule agonist of mAR and could be a novel therapeutic agent for advanced prostate cancer, especially when taking into account the absence of androgenic actions and (liver) toxicity.

The enigmatic roles of caspases in tumor development

One function ascribed to apoptosis is the suicidal destruction of potentially harmful cells, such as cancerous cells. Hence, their growth depends on evasion of apoptosis, which is considered as one of the hallmarks of cancer. Apoptosis is ultimately carried out by the sequential activation of initiator and executioner caspases, which constitute a family of intracellular proteases involved in dismantling the cell in an ordered fashion. In cancer, therefore, one would anticipate caspases to be frequently rendered inactive, either by gene silencing or by somatic mutations. From clinical data, however, there is little evidence that caspase genes are impaired in cancer. Executioner caspases have only rarely been found mutated or silenced, and also initiator caspases are only affected in particular types of cancer. There is experimental evidence from transgenic mice that certain initiator caspases, such as caspase-8 and -2, might act as tumor suppressors. Loss of the initiator caspase of the intrinsic apoptotic pathway, caspase-9, however, did not promote cellular transformation. These data seem to question a general tumor-suppressive role of caspases. We discuss several possible ways how tumor cells might evade the need for alterations of caspase genes. First, alternative splicing in tumor cells might generate caspase variants that counteract apoptosis. Second, in tumor cells caspases might be kept in check by cellular caspase inhibitors such as c-FLIP or XIAP. Third, pathways upstream of caspase activation might be disrupted in tumor cells. Finally, caspase-independent cell death mechanisms might abrogate the selection pressure for caspase inactivation during tumor development. These scenarios, however, are hardly compatible with the considerable frequency of spontaneous apoptosis occurring in several cancer types. Therefore, alternative concepts might come into play, such as compensatory proliferation. Herein, apoptosis and/or non-apoptotic functions of caspases may even promote tumor development. Moreover, experimental evidence suggests that caspases might play non-apoptotic roles in processes that are crucial for tumorigenesis, such as cell proliferation, migration, or invasion. We thus propose a model wherein caspases are preserved in tumor cells due to their functional contributions to development and progression of tumors.

In vitro modulation of Bcl-2 levels in small cell lung cancer cells: effects on cell viability

Small cell lung cancer (SCLC) is an aggressive disease, representing 15% of all cases of lung cancer, has high metastatic potential and low prognosis that urgently demands the development of novel therapeutic approaches. One of the proposed approaches has been the down-regulation of BCL2, with poorly clarified and controversial therapeutic value regarding SCLC. The use of anti-BCL2 small interfering RNA (siRNA) in SCLC has never been reported. The aim of the present study was to select and test the in vitro efficacy of anti-BCL2 siRNA sequences against the protein and mRNA levels of SCLC cells, and their effects on cytotoxicity and chemosensitization. Two anti-BCL2 siRNAs and the anti-BCL2 G3139 oligodeoxynucleotide (ODN) were evaluated in SCLC cells by the simultaneous determination of Bcl-2 and viability using a flow cytometry method recently developed by us in addition to Western blot, real-time reverse-transcription PCR, and cell growth after single and combined treatment with cisplatin. In contrast to previous reports about the use of ODN, a heterogeneous and up to 80% sequence-specific Bcl-2 protein knockdown was observed in the SW2, H2171 and H69 SCLC cell lines, although without significant sequence-specific reduction of cell viability, cell growth, or sensitization to cisplatin. Our results question previous data generated with antisense ODN and supporting the present concept of the therapeutic interest in BCL2 silencing per se in SCLC, and support the growing notion of the necessity of a multitargeting molecular approach for the treatment of cancer.

Phyllanthus spp. induces selective growth inhibition of PC-3 and MeWo human cancer cells through modulation of cell cycle and induction of apoptosis

BACKGROUND

Phyllanthus is a traditional medicinal plant that has been used in the treatment of many diseases including hepatitis and diabetes. The main aim of the present work was to investigate the potential cytotoxic effects of aqueous and methanolic extracts of four Phyllanthus species (P.amarus, P.niruri, P.urinaria and P.watsonii) against skin melanoma and prostate cancer cells.

METHODOLOGY/PRINCIPAL FINDINGS

Phyllanthus plant appears to possess cytotoxic properties with half-maximal inhibitory concentration (IC(50)) values of 150-300 µg/ml for aqueous extract and 50-150 µg/ml for methanolic extract that were determined using the MTS reduction assay. In comparison, the plant extracts did not show any significant cytotoxicity on normal human skin (CCD-1127Sk) and prostate (RWPE-1) cells. The extracts appeared to act by causing the formation of a clear "ladder" fragmentation of apoptotic DNA on agarose gel, displayed TUNEL-positive cells with an elevation of caspase-3 and -7 activities. The Lactate Dehydrogenase (LDH) level was lower than 15% in Phyllanthus treated-cancer cells. These indicate that Phyllanthus extracts have the ability to induce apoptosis with minimal necrotic effects. Furthermore, cell cycle analysis revealed that Phyllanthus induced a Go/G1-phase arrest on PC-3 cells and a S-phase arrest on MeWo cells and these were accompanied by accumulation of cells in the Sub-G1 (apoptosis) phase. The cytotoxic properties may be due to the presence of polyphenol compounds such as ellagitannins, gallotannins, flavonoids and phenolic acids found both in the water and methanol extract of the plants.

CONCLUSIONS/SIGNIFICANCE

Phyllanthus plant exerts its growth inhibition effect in a selective manner towards cancer cells through the modulation of cell cycle and induction of apoptosis via caspases activation in melanoma and prostate cancer cells. Hence, Phyllanthus may be sourced for the development of a potent apoptosis-inducing anticancer agent.

Malignant mixed Mullerian tumors of the uterus: histopathological evaluation of cell cycle and apoptotic regulatory proteins

Aim

The aim of our study was to evaluate survival outcomes in malignant mixed Mullerian tumors (MMMT) of the uterus with respect to the role of cell cycle and apoptotic regulatory proteins in the carcinomatous and sarcomatous components.

Methods

23 cases of uterine MMMT identified from the Saskatchewan Cancer Agency (1970-1999) were evaluated. Immunohistochemical expression of Bad, Mcl-1, bcl-x, bak, mdm2, bax, p16, p21, p53, p27, EMA, Bcl-2, Ki67 and PCNA was correlated with clinico-pathological data including survival outcomes.

Results

Histopathological examination confirmed malignant epithelial component with homologous (12 cases) and heterologous (11 cases) sarcomatous elements. P53 was strongly expressed (70-95%) in 15 cases and negative in 5 cases. The average survival in the p53+ve cases was 3.56 years as opposed to 8.94 years in p53-ve cases. Overexpression of p16 and Mcl-1 were observed in patients with longer survival outcomes (> 2 years). P16 and p21 were overexpressed in the carcinomatous and sarcomatous elements respectively. Cyclin-D1 was focally expressed only in the carcinomatous elements.

Conclusions

Our study supports that a) cell cycle and apoptotic regulatory protein dysregulation is an important pathway for tumorigenesis and b) p53 is an important immunoprognostic marker in MMMT of the uterus.

Polymorphisms in the CASPASE Genes and Survival in Patients With Early-Stage Non–Small-Cell Lung Cancer

Purpose

This study was conducted to determine the impact of potentially functional polymorphisms in the CASPASE (CASP) genes on the survival of early-stage non–small-cell lung cancer (NSCLC) patients.

Patients and Methods

Four hundred eleven consecutive patients with surgically resected NSCLC were enrolled. Nine potentially functional polymorphisms in the CASP3, CASP7, CASP8, CASP9, and CASP10 genes were investigated. The genotype and haplotype associations with overall survival (OS) and disease-free survival (DFS) were analyzed.

Results

Patients with the rs2227310 GG genotype had a significantly decreased OS and DFS compared with patients with the CC + CG genotype (adjusted hazard ratio [aHR] for OS, 1.67; 95% CI, 1.19 to 2.35; P = .003; aHR for DFS, 1.62; 95% CI, 1.19 to 2.22; P = .002). The rs4645981C>T genotype also had a significant effect on OS and DFS (under a recessive model; aHR for OS, 2.00; 95% CI, 1.04 to 3.85; P = .04; aHR for DFS, 2.76; 95% CI, 1.58 to 4.80; P = .0003). When the rs2227310 and rs4645981 genotypes were combined, patients with one or two bad genotypes had worse OS and DFS compared with those who had zero bad genotypes (aHR for OS, 1.75; 95% CI, 1.25 to 2.45; P = .001; aHR for DFS, 1.66; 95% CI, 1.23 to 2.26; P = .001).

Conclusion

The CASP7 rs2227310 and CASP9 rs4645981 polymorphisms may affect survival in early-stage NSCLC. The analysis of these polymorphisms can help identify patients at high risk for a poor disease outcome.

Intrinsic anticarcinogenic effects of Piper sarmentosum ethanolic extract on a human hepatoma cell line

Background

Piper sarmentosum, locally known as kaduk is belonging to the family of Piperaceae. It is our interest to evaluate their effect on human hepatoma cell line (HepG2) for the potential of anticarcinogenic activity.

Results

The anticarcinogenic activity of an ethanolic extract from Piper sarmentosum in HepG2 and non-malignant Chang's liver cell lines has been previously determined using (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide) (MTT) assays, where the IC₅₀ value was used as a parameter for cytotoxicity. The ethanolic extract that showed anticarcinogenic properties in HepG2 cells had an IC₅₀ of 12.5 μg mL^-1, while IC₅₀ values in the non-malignant Chang's liver cell line were greater than 30 μg mL^-1. Apoptotic morphological changes in HepG2 cells were observed using an inverted microscope and showed chromatin condensation, cell shrinkage and apoptotic bodies following May-Grunwald-Giemsa's staining. The percentage of apoptotic cells in the overall population (apoptotic index) showed a continuously significant increase (p < 0.05) in 12.5 μg mL^-1 ethanolic extract-treated cells at 24, 48 and 72 hours compared to controls (untreated cells). Following acridine orange and ethidium bromide staining, treatment with 10, 12 and 14 μg mL^-1 of ethanolic extracts caused typical apoptotic morphological changes in HepG2 cells. Molecular analysis of DNA fragmentation was used to examine intrinsic apoptosis induced by the ethanolic extracts. These results showed a typical intrinsic apoptotic characterisation, which included fragmentation of nuclear DNA in ethanolic extract-treated HepG2 cells. However, the non-malignant Chang's liver cell line produced no DNA fragmentation. In addition, the DNA genome was similarly intact for both the untreated non-malignant Chang's liver and HepG2 cell lines.

Conclusion

Therefore, our results suggest that the ethanolic extract from P. sarmentosum induced anticarcinogenic activity through an intrinsic apoptosis pathway in HepG2 cells in vitro.

Chemotherapy synergizes with radioimmunotherapy targeting La autoantigen in tumors

BACKGROUND

To date, inefficient delivery of therapeutic doses of radionuclides to solid tumors limits the clinical utility of radioimmunotherapy. We aim to test the therapeutic utility of Yttrium-90 ((90)Y)-radio-conjugates of a monoclonal antibody, which we showed previously to bind specifically to the abundant intracellular La ribonucleoprotein revealed in dead tumor cells after DNA-damaging treatment.

METHODOLOGY/PRINCIPAL FINDINGS

Immunoconjugates of the DAB4 clone of the La-specific monoclonal antibody, APOMAB, were prepared using the metal chelator, 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA), and then radiolabeled with (90)Y. Mice bearing established subcutaneous tumors were treated with (90)Y-DOTA-DAB4 alone or after chemotherapy. Non-radiosensitizing cyclophosphamide/etoposide chemotherapy was used for the syngeneic EL4 lymphoma model. Radiosensitizing cisplatin/gemcitabine chemotherapy was used for the syngeneic Lewis Lung carcinoma (LL2) model, and for the xenograft models of LNCaP prostatic carcinoma and Panc-1 pancreatic carcinoma. We demonstrate the safety, specificity, and efficacy of (90)Y-DOTA-DAB4-radioimmunotherapy alone or combined with chemotherapy. EL4 lymphoma-bearing mice either were cured at higher doses of radioimmunotherapy alone or lower doses of radioimmunotherapy in synergy with chemotherapy. Radioimmunotherapy alone was less effective in chemo- and radio-resistant carcinoma models. However, radioimmunotherapy synergized with radiosensitizing chemotherapy to retard significantly tumor regrowth and so prolong the survival of mice bearing LL2, LNCaP, or Panc-1 subcutaneous tumor implants.

CONCLUSIONS/SIGNIFICANCE

We report proof-of-concept data supporting a unique form of radioimmunotherapy, which delivers bystander killing to viable cancer cells after targeting the universal cancer antigen, La, created by DNA-damaging treatment in neighboring dead cancer cells. Subsequently we propose that DAB4-targeted ionizing radiation induces additional cycles of tumor cell death, which further augments DAB4 binding to produce a tumor-lethal 'genotoxic chain reaction'. Clinically, this approach may be useful as consolidation treatment after a drug-induced cell death among (small-volume) metastatic deposits, the commonest cause of cancer death. This article is part II of a two-part series providing proof-of-concept for the diagnostic and therapeutic use of the DAB4 clone of the La-specific monoclonal antibody, APOMAB.

APOMAB, a La-specific monoclonal antibody, detects the apoptotic tumor response to life-prolonging and DNA-damaging chemotherapy

Background

Antineoplastic therapy may impair the survival of malignant cells to produce cell death. Consequently, direct measurement of tumor cell death in vivo is a highly desirable component of therapy response monitoring. We have previously shown that APOMAB® representing the DAB4 clone of a La/SSB-specific murine monoclonal autoantibody is a malignant cell-death ligand, which accumulates preferentially in tumors in an antigen-specific and dose-dependent manner after DNA-damaging chemotherapy. Here, we aim to image tumor uptake of APOMAB® (DAB4) and to define its biological correlates.

Methodology/Principal Findings

Brisk tumor cell apoptosis is induced in the syngeneic EL4 lymphoma model after treatment of tumor-bearing mice with DNA-damaging cyclophosphamide/etoposide chemotherapy. Tumor and normal organ accumulation of Indium 111 (¹¹¹In)-labeled La-specific DAB4 mAb as whole IgG or IgG fragments was quantified by whole-body static imaging and organ assay in tumor-bearing mice. Immunohistochemical measurements of tumor caspase-3 activation and PARP-1 cleavage, which are indicators of early and late apoptosis, respectively, were correlated with tumor accumulation of DAB4. Increased tumor accumulation of DAB4 was associated directly with both the extent of chemotherapy-induced tumor cell death and DAB4 binding per dead tumor cell. Tumor DAB4 accumulation correlated with cumulative caspase-3 activation and PARP-1 cleavage as tumor biomarkers of apoptosis and was directly related to the extended median survival time of tumor-bearing mice.

Conclusions/Significance

Radiolabeled La-specific monoclonal antibody, DAB4, detected dead tumor cells after chemotherapy, rather than chemosensitive normal tissues of gut and bone marrow. DAB4 identified late apoptotic tumor cells in vivo. Hence, radiolabeled DAB4 may usefully image responses to human carcinoma therapy because DAB4 would capture the protracted cell death of carcinoma. We believe that the ability of radiolabeled DAB4 to rapidly assess the apoptotic tumor response and, consequently, to potentially predict extended survival justifies its future clinical development as a radioimmunoscintigraphic agent.

This article is part I of a two-part series providing proof-of-concept for the the diagnostic and therapeutic use of a La-specific monoclonal antibody, the DAB4 clone of which is represented by the registered trademark, APOMAB®.

Proliferation and apoptosis of tumour cells before and after neoadjuvant therapy for high-grade extremity sarcomas: divergent associations with tumour response and prognosis

AIMS

To evaluate proliferation and apoptosis in high-grade sarcomas of the extremities before and after preoperative radio-hyperthermo-chemotherapy (RHC) and to determine the relationship between these parameters and treatment outcomes.

METHODS AND RESULTS

Pre- and post-RHC specimens of 41 soft tissue and bone tumours were immunohistochemically stained for minichromosome maintenance protein (MCM) 2 and caspase 3 as proliferation and apoptosis markers, respectively, based on a preliminary study comparing them with conventional markers. Indices were calculated as a percentage of positive cells by counting tumour cells in the most frequently labelled areas. MCM2, caspase 3 and MCM2/caspase 3 (growth) indices were 45.3 +/- 21.9%, 4.1 +/- 7.1% and 82.9 +/- 104.5, respectively, in pre-RHC specimens and 35.4 +/- 30.8%, 39.2 +/- 34.6% and 5.3 +/- 11.7, respectively, in post-RHC specimens. Response scores showed positive correlation with pre-RHC MCM2 and post-RHC caspase 3 indices, inverse correlation with post-RHC MCM2 and post-RHC growth indices and no correlation with prognosis. Multivariate analysis revealed high pre-RHC MCM2 and high post-RHC growth indices as significant unfavourable prognostic factors.

CONCLUSIONS

High proliferative activity in untreated sarcoma may predict good response to neoadjuvant therapy, but poor prognosis, whereas a high growth index, i.e. high proliferation:apoptosis ratio in a post-neoadjuvant therapy tumour specimen may indicate poor response and poor prognosis.

Vincristine and lomustine induce apoptosis and p21(WAF1) up-regulation in medulloblastoma and normal human epithelial and fibroblast cells

Medulloblastomas arise in the cerebellum and are the most common pediatric primary malignant brain tumors. Currently, medulloblastoma patients are best treated with surgical removal of the tumor, adjuvant radiation therapy and chemotherapy. The chemotherapeutic agents that showed efficiency against medulloblastomas include lomustine and vincristine. However, the effects of these drugs on medulloblastomas as well as on other cell types is still not well defined. In the present report we present evidence that the cytotoxic effect of these drugs is not specific for medulloblastoma cells but includes also normal fibroblast and epithelial cells. We have also shown that vincristine and lomustine trigger apoptosis in all these cells through the mitochondrial pathway via decrease in the level of the anti-apoptosis proteins Bcl-2 and Bcl-xl, respectively. Intriguingly, the proportion of apoptotic cells induced in medulloblastoma and normal epithelial and fibroblastic cells was similar. In addition, vincristine induced low proportion of necrosis in medulloblastoma and normal fibroblast cells. Interestingly, while vincristine induced cell cycle delay in G2/M phase in normal as well as medulloblastoma cells, lomustine effect on the cell cycle was specific for medulloblastoma cells. Furthermore, we have shown that vincristine and lomustine up-regulated p21 protein level in a p53-independent manner. These results shed more light on the biological effects of vincristine and lomustine and show that lomustine is a more specific and potent anti-medulloblastoma agent.

Polymorphisms in the survivin gene and the risk of lung cancer

BACKGROUND

Survivin is an apoptosis inhibitor and plays an important role in the development and progression of cancer. Polymorphisms in the survivin gene may influence survivin production or activity, thereby modulating susceptibility to lung cancer. To test this hypothesis, we investigated the association between survivin polymorphisms and the risk of lung cancer in a Korean population.

METHODS

We first screened for polymorphisms in the survivin gene by direct sequencing of genomic DNA samples from 27 healthy Koreans. We selected identified SNPs based on their frequency, linkage disequilibrium status and haplotype tagging status, and then genotyped the selected SNPs in 582 lung cancer patients and 582 healthy controls who were frequency matched for age and gender.

RESULTS

We identified 8 single nucleotide polymorphisms (SNPs): 6 known SNPs [-644T>C, -625G>C, -31C>G, 9194A>G (K129E), 9386T>C and 9809T>C] and 2 novel SNPs (9974C>T and 10347G>A). Among the SNPs studied, only the -31C>G genotype distribution was significantly different between the cases and controls (P=0.04). Individuals with at least one -31G allele were at a significantly decreased risk of lung cancer compared to those individuals with the -31CC genotype [adjusted odds ratio (OR)=0.74, 95% confidence interval (CI)=0.57-0.96, P=0.02]. When the lung cancer cases were categorized by tumor histology, the -31G allele was associated with a significantly decreased risk of adenocarcinoma (adjusted OR=0.59, 95% CI=0.41-0.84, P=0.003). Consistent with the results of the genotyping analysis, the -625G/-31G/9194A/9809T haplotype carrying the -31G allele was associated with a significantly decreased risk of adenocarcinoma (adjusted OR=0.56, 95% CI=0.40-0.77, P=0.0004). The promoter assay revealed the -31G allele to have a significantly lower promoter activity than the -31C allele.

CONCLUSION

These results suggest that the survivin -31C>G polymorphism influences survivin expression, thus contributing to the genetic susceptibility to lung cancer.

Zerumbone induced apoptosis in liver cancer cells via modulation of Bax/Bcl-2 ratio

BACKGROUND

Zerumbone is a cytotoxic component isolated from Zingiber zerumbet Smith, a herbal plant which is also known as lempoyang. This new anticancer bioactive compound from Z. zerumbet was investigated for its activity and mechanism in human liver cancer cell lines.

RESULTS

Zerumbone significantly showed an antiproliferative activity upon HepG2 cells with an IC50 of 3.45 +/- 0.026 microg/ml. Zerumbone was also found to inhibit the proliferation of non-malignant Chang Liver and MDBK cell lines. However the IC50 obtained was higher compared to the IC50 for HepG2 cells (> 10 microg/ml). The extent of DNA fragmentation was evaluated by the Tdt-mediated dUTP nick end labelling assay which showed that, zerumbone significantly increased apoptosis in HepG2 cells in a time-course manner. In detail, the apoptotic process triggered by zerumbone involved the up-regulation of pro-apoptotic Bax protein and the suppression of anti-apoptotic Bcl-2 protein expression. The changes that occurred in the levels of this antagonistic proteins Bax/Bcl-2, was independent of p53 since zerumbone did not affect the levels of p53 although this protein exists in a functional form. Western blotting analysis for Bax protein was further confirmed qualitatively with an immunoassay that showed the distribution of Bax protein in zerumbone-treated cells.

CONCLUSION

Therefore, zerumbone was found to induce the apoptotic process in HepG2 cells through the up and down regulation of Bax/Bcl-2 protein independently of functional p53 activity.

Glioma cells suppress hypoxia-induced endothelial cell apoptosis and promote the angiogenic process

The hypoxic microenvironment of solid tumors is associated with malignant progression and it renders tumors more resistant to cancer therapies. Endothelial cell damage may occur following hypoxic conditions and lead to dysfunction; however, endothelial cells in tumors survive hypoxic conditions providing nutrients and oxygen to facilitate tumor growth. In this study, we investigated the effects of tumor-conditioned medium on hypoxia-induced changes in endothelial cell growth, migration and survival. Tumor conditioned medium collected from U87 human glioblastoma cells were applied to endothelial cultures in normoxia or hypoxia conditions. Hypoxia caused a reduction in clonogenic cell survival response and an increase of the sub-G1 phase of the cell cycle in endothelial cells. Cell migration was measured by spheroid and wound-induced migration assays and hypoxia compared with normoxia significantly increased the number of migrating endothelial cells. Nuclear staining with Hoechst 33258 and caspase-9 and -3 activation in endothelial cells show that hypoxia-induced apoptosis involves caspase-dependent mechanism. Exposure to hypoxia caused an increase in gene expression of VEGF and VEGFR2 and activities of MMP-2 and MMP-9. Furthermore, hypoxia induced an increase in capillary-like structure formation in endothelial cells seeded into Matrigel. Tumor conditioned medium enhanced survival and rescued endothelial cells from apoptosis induced by hypoxia. These molecular changes in endothelial cells could, in part, contribute to the angiogenic response that occurs during hypoxia-induced angiogenesis in glial tumors.

Expression of survivin and XIAP for DMBA-induced hamster buccal pouch squamous cell carcinogenesis is associated with p53 accumulation

Apoptosis (programmed cell death) is regulated by a number of inhibitory or stimulatory factors. One such family of antiapoptotic proteins is the inhibitors of apoptosis proteins (IAPs), of which survivin and X chromosome-linked IAP (XIAP) are members. The expression of survivin and XIAP, as well as their association with p53, in chemically-induced experimental oral carcinogenesis is not completely understood. The objective of the present study was, therefore, to investigate the protein expression of these two IAP family members and their relationship with p53 status, in 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch squamous cell carcinogenesis. Immunohistochemical analysis of survivin, XIAP and p53 protein expression was performed in DMBA-induced pouch squamous cell carcinogenesis. Fifty outbred, young (6 weeks), male Syrian golden hamsters (Mesocricatus auratus) were randomly divided into three experimental groups (each group consisting of 10 animals treated with DMBA for 3-, 7- or 14-weeks), and two control groups (with 10 animals in each). The pouches of the three experimental groups were painted bilaterally with a 0.5% DMBA solution three times a week. The treatment protocol for animals in one of the control groups was identical with only mineral oil applied, while the other control group remained untreated throughout the experiment. Survivin staining could not be detected by immunohistochemistry in any of the untreated or mineral oil treated hamster pouch-tissue specimens. Cytoplasmic staining of survivin proteins was apparent in the entire epithelial layer (excluding the keratinized layer) in all 3-week DMBA treated pouch-tissue analyzed. In addition, cytoplasmic survivin staining was observed in all specimens of 7- and 14-week DMBA treated pouch-tissue. XIAP positivity was confined to the outermost keratinized layer of the pouch-tissue from control animals and those treated with DMBA for 3-weeks. However, XIAP staining was detected in the whole epithelial layer (except the basal layer) in 7- and 14-week DMBA treated pouch-tissue. p53 was not detected in any untreated and mineral oil treated pouch-tissue, whereas nuclear p53 staining was observed for all 3-, 7- and 14-week DMBA treated pouch-tissue. The results of this study demonstrate the association between survivin/XIAP and p53 expression in this experimental model system for oral carcinogenesis, although their exact interactions remain to be clarified. Moreover, our findings suggest that the DMBA-induced hamster buccal pouch mucosa may serve as an appropriate experimental model for investigation of potential novel therapeutic tools for oral squamous-cell carcinomas.

Extent, relationship and prognostic significance of apoptosis and cell proliferation in synovial sarcoma

AIMS

To analyse the extent, relationship and clinical significance of apoptosis and cell proliferation in synovial sarcoma.

METHODS

Apoptosis was detected by TUNEL, and expression of Ki-67, Bcl-2, Bax and p53 was examined immunohistochemically in 72 synovial sarcomas. Their relation and correlation with clinicopathological parameters and survival rate were analysed.

RESULTS

The average values of apoptosis index (AI) and Ki-67 labelling index (LI) were 0.76% and 28.30%, respectively. Both AI and Ki-67 LI in large-volume, high-grade and advanced-stage synovial sarcomas were significantly higher than those in small-volume, low-grade and early-stage ones (P<0.05 for all). And there was a linear relationship between AI and Ki-67 LI (r=0.751, P<0.001). All examined synovial sarcomas were positive for Bcl-2 and Bax, and only 20.8% cases showed expression of p53 protein. The expressions of Bcl-2, Bax and p53 were also significantly correlated with AI (P=0.005, P=0.002, P=0.037, respectively). In addition, patients with high AI (>0.76%) had poor prognosis (log-rank test; P=0.007).

CONCLUSIONS

Alterations in apoptosis and cell proliferation activity might be responsible for the pathogenesis and behaviour of synovial sarcoma. Increased rate of apoptosis in synovial sarcoma was considered to be an indicator of poor prognosis. In addition, apoptosis in synovial sarcoma may be controlled by multiple apoptosis-regulating mechanisms, including the Bcl-2 family and p53 protein.

Polymorphisms in the caspase-8 gene and the risk of lung cancer

Caspase-8 (CASP-8) is an initiator CASP in the cell death receptor-mediated apoptotic pathway, and plays an important role in the development of cancer. Polymorphisms and their haplotypes in the CASP-8 gene can result in alterations in CASP-8 expression and/or activity, thereby modulating the susceptibility to lung cancer. To test this hypothesis, we examined the association of -678_-673delAGTAAG (-678del) and IVS12-19G-->A polymorphisms and their haplotypes with the risk of lung cancer in a Korean population. The CASP-8 genotypes were determined in 432 lung cancer patients and 432 healthy age- and gender-matched control subjects. The distributions of the CASP-8 -678del and IVS12-19G-->A genotypes were not significantly different between the overall lung cancer cases and the controls. When the cases were categorized by tumor histology, however, the IVS12-19 AA genotype and the combined IVS12-19 GA + AA genotype were associated with a significantly decreased risk of small cell carcinoma (SmCC) compared with the IVS12-19 GG genotype [adjusted odds ratio (OR) = 0.14, 95% confidence interval (CI) = 0.03-0.64, P = 0.01; and adjusted OR = 0.56, 95% CI = 0.33-0.96, P = 0.03, respectively]. Consistent with the genotyping analyses, the -678del-/IVS12-19A haplotype containing 94% of the IVS12-19A allele in the study population was associated with a significantly decreased risk of SmCC compared with the -678del-/IVS12-19G (adjusted OR = 0.58, 95% CI = 0.36-0.93, P = 0.023, and Pc = 0.046). These findings suggest that the CASP-8 gene may contribute to an inherited predisposition to SmCC of the lung.

The regression of a canine Langerhans cell tumour is associated with increased expression of IL-2, TNF-alpha, IFN-gamma and iNOS mRNA

Canine cutaneous histiocytoma is a benign epidermal neoplasm of Langerhans cell origin, which usually displays spontaneous regression. Based on the degree of lymphocytic infiltration, 30 histiocytomas were classified into four groups representing different stages of tumour regression. To elucidate further the mechanisms of the antitumour immune response CD3+, CD21+, CD4+, CD8+ and myeloid/histiocyte antigen+ inflammatory cells were differentiated by immunohistochemistry and quantified. In addition, the number of apoptotic cells was detected using the TdT-mediated biotin-dUTP nick-end labelling (TUNEL) method. Furthermore, the expression of interleukin- (IL-2), IL-12(p40), tumour necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma), IL-10 and transforming growth factor-beta (TGF-beta) as well as inducible nitric oxid synthase (iNOS) mRNA was determined by reverse transcription-polymerase chain reaction (RT-PCR). Phenotyping of inflammatory cells revealed a significantly increased infiltration of all lymphocyte subsets and myeloid/histiocytic cells with the onset of tumour regression. The latter was significantly correlated to up-regulation of IL-2, TNF-alpha, IFN-gamma and iNOS mRNA expression. Expression of remaining cytokines and percentage of apoptotic cells showed no group-specific changes. The results indicate an initial infiltration of CD4+ T cells followed by increased expression of Th1 cytokines and recruitment of antitumour effector cells as the principal mechanism for tumour regression. Canine cutaneous histiocytoma is a unique example for an effective immune response in a naturally occurring neoplasm derived from epidermal Langerhans cells and might represent a valuable animal model to investigate tumour immunity.

Apoptosis in epithelial ovarian tumours Prognostic significance of clinical and histopathologic factors and its association with the immunohistochemical expression of apoptotic regulatory proteins (p53, bcl-2 and bax)

OBJECTIVE

The objective was to establish the importance of apoptosis-related genes and the apoptotic index (AI) as prognostic factors in patients with epithelial ovarian tumours.

MATERIAL AND METHODS

Tumour specimens from 130 epithelial ovarian tumours were examined for expression of p53, bcl-2 and bax proteins. The apoptotic index was evaluated by modified terminal deoxynucleotide-transferase-mediated digoxigenin triphosphate-biotin nick end-labelling (TUNEL) methods and by haematoxylin-eosin (H-E) staining. Other clinical and histopathological variables were also analysed. Statistical analyses were performed using the SPSS 10.0 package.

RESULTS

The apoptotic index detected by H-E and enzymatic assay was high in the majority of carcinomas (serous, endometrioid and clear cell (p=0.001). In the univariate survival analysis, high apoptotic index, high p53 and low bcl-2 expression, significantly correlated with shorter survival and shorter disease-free periods (p<0.01). In multivariate analysis the age (p=0.026; CI: 1.035-1.066 and p=0.011; CI: 1.835-2.077), FIGO stage (p=0.017; CI: 1.385-4.514 and p=0.024; CI: 1.217-1.940), p53 expression (p=0.03; CI: 1.017-1.627 and p=0.02; CI: 1.050-2.350) and apoptotic index (p=0.019; CI: 1.375-1.750 and p=0.019; CI: 1.442-2.085) were revealed to be independent prognostic factors for survival and recurrence, respectively.

CONCLUSIONS

Our results indicate that the apoptotic index and p53 nuclear accumulation are independent predictive factors of recurrence and short survival. Our data also suggest different patterns of alterations for the various tumour types.

Irregularly shaped inclusion cysts display increased expression of Ki67, Fas, Fas ligand, and procaspase-3 but relatively little active caspase-3

Human ovarian cancers are thought to arise from sequestered ovarian surface epithelial (OSE) cells that line the wall of inclusion cysts. Nevertheless, the early events toward neoplasia are not well understood. In this study, immunoreactivity for apoptotic proteins in human OSE of control and tumor ovarian sections was examined. Ki67, a marker for cell proliferation, was generally absent in the flat-to-cuboidal OSE cells on the ovarian surface and in regularly shaped inclusion cysts. Fas, Fas ligand, and caspase-3, components of the apoptotic pathway, were also largely absent. Ki67, Fas, Fas ligand, and procaspase-3 expression, though not active caspase-3 expression, was more frequently observed in epithelial cells lining irregularly shaped inclusion cysts, particularly in the columnar and Müllerian-like OSE cell types that resembled ovarian tumor OSE cells. Immunoreactivity for these factors as well as active caspase-3 was found frequently in ovarian tumors. We postulate that the appearance of the Fas system and its related proteins in sequestered columnar OSE cells of irregularly shaped inclusion cysts may contribute to balance cell growth with cell death, although little active caspase-3 expression was observed. Further studies are required to identify whether inhibition of apoptosis in inclusion cysts is an early event in ovarian carcinogenesis.

Increased occurrence of caspase-dependent apoptosis in unfavorable neuroblastomas

Neuroblastoma frequently shows spontaneous regression in which two distinct types of programmed cell death, ie, caspase-dependent apoptosis and H-Ras-mediated autophagic degeneration, have been suggested to play a key role. The current study was conducted to determine which of these cell suicide pathways predominated in this tumor regression. Periodic acid-Schiff (PAS) staining and immunostaining for H-Ras and for the full-length and cleaved forms of caspase-3, poly (ADP-ribose) polymerase (PARP), and lamin A were carried out on 55 archival tumor specimens. The incidence of caspase-dependent apoptosis in each tumor was quantified by cleaved lamin A staining and compared with clinicopathologic prognostic factors. Although a recent report has shown that neuroblastic cells undergoing autophagic degeneration were readily detectable by PAS and H-Ras staining, we could not confirm this result in any of our samples with the exception of one tumor. Instead, many of our neuroblastoma samples showed nonspecific PAS and Ras staining in areas of necrosis, suggesting that autophagic "degeneration" indeed corresponds to coagulation necrosis or oncosis. Unexpectedly, the incidence of caspase-dependent apoptosis was significantly correlated with indicators of a poor prognosis in these tumors, including Shimada's unfavorable histology, MYCN amplification, and a higher mitosis-karyorrhexis index, but not with factors related to tumor regression such as clinical stage and mass screening. These results indicate that neither caspase-dependent apoptosis nor autophagic "degeneration" may be involved in spontaneous neuroblastoma regression. This suggests that other mechanisms, perhaps such as tumor maturation, may be responsible for this phenomenon.

Abnormalities of cell structures in tumors: apoptosis in tumors

A conceptual shift has occurred in recent years from considering cancer as simply a disease of deregulated cell proliferation to a view that incorporates the aberrant control of apoptosis into the equation. Apoptosis is an organized, genetically programmed cell death process by which multicellular organisms specifically destroy, dismantle and dispose of cells. In cancer cells, this tightly controlled process is suppressed by genetic lesions, allowing cancer cells to survive beyond their normal life span even in hostile environments that are prone to hypoxia and lack many trophic factor supports. In the last two decades, cancer researchers have made great strides in our understanding of the underlying molecular mechanism of apoptosis in chemoresistance generation and tumorigenesis. This tremendous increase in our knowledge of apoptosis in tumors has greatly impacted our perspective on carcinogenesis. Key regulators of apoptosis such as members of the Inhibitors of Apoptosis family and Bcl-2 family have been shown to play a pivotal role in allowing most cancer cells to escape apoptosis. The identification of specific targets involved in the suppression of apoptosis in cancer cells has facilitated the design and development of therapeutic strategies based on rational molecular approaches that aim to modulate apoptotic pathways. Many promising apoptosis-dependent strategies have been translated into clinical trials in the continued assessment of regimens that can effectively eradicate cancers.

p12CDK2-AP1 gene therapy strategy inhibits tumor growth in an in vivo mouse model of head and neck cancer

PURPOSE

To test the potential of p12(CDK2-AP1) (p12), a cell cycle regulator and cyclin-dependent kinase-2-associating protein commonly down-regulated in head and neck squamous cell carcinoma ( approximately 70%), as a gene therapy in inhibiting head and neck squamous cell carcinoma growth in vivo.

EXPERIMENTAL DESIGN

We addressed the effect of p12 expression on tumor growth by using a well-established squamous cell carcinoma VII/SF floor of mouth xenograft mouse model. The effect of therapy on tumor growth was determined for: (a) no treatment, (b) PBS, (c) vehicle (1,2-dioleoyloxy-3-trimethylammonium propane:cholesterol liposomes / 5% dextrose), (d) empty vector controls, and (e) p12-encoding vector experimental groups.

RESULTS

p12 gene therapy significantly induced antitumor effects as compared with controls, including (a) size and weight of p12-treated tumors decreased by 51% to 72% compared with all controls (P < 0.02), (b) tumor growth rate post-therapy was inhibited by 55% to 64% compared with empty vector controls (P < 0.0001), and (c) p12 expression was higher in p12-treated than controls (P < 0.002) by two-tailed t test analyses. Mechanistically, p12 treatment affected cell turnover kinetics as assessed by apoptotic and cell proliferation indices. p12 therapy significantly increased terminal nucleotidyl transferase-mediated nick end labeling (P < 0.05) and morphology-based apoptotic indices (P < 0.05) as well as significantly decreased Ki-67 cell proliferation indices (P < 0.001) compared with controls, resulting in a net cell turnover reduction in p12-treated tumors.

CONCLUSIONS

We show that this novel therapeutic modality can significantly induce antitumor responses in vivo. These results support a role for p12 as a novel tumor growth suppressor gene therapy and suggest that optimization and/or combination with current therapies may hold considerable promise in preparation for clinical trials.

Activation and relocalization of caspase 3 during the apoptotic cascade of human mesothelioma cells

Apoptosis plays an important role in cancer biology. We investigated the expression of caspases 3 and 8 in malignant mesothelioma and malignant mesothelioma cell lines and putative changes in their ultrastructural expression prior and after exposure to epirubicin. Further studies were conducted to compare these changes to the localization and expression of the bcl-2 group of proteins bcl-X, bax and mcl-1, and Fas-Fas ligand in the same cells. In the histological samples, caspase 3 and 8 immunoreactivity was seen in 27/37 (73%) and 16/37 (43%) of the mesotheliomas. The immunostaining was cytoplasmic diffuse, granular, and occasionally nuclear. All six mesothelioma cell lines expressed caspases 3 and 8 by immunoblotting. After exposure to epirubicin the extent of apoptosis was increased in all cell lines investigated, being weakest in the most resistant M38K cell line. Immunoelectron microscopy revealed immunogold labeling for caspases 3 and 8 in the mitochondria with the accumulation of caspase 3 in the apoptotic bodies, while the mitochondrial localization of the bcl-2 proteins appeared to be very stable. Fas receptor could be detected by flow cytometry, whereas the most resistant cell line (M38K) lacked Fas ligand when assessed by RT-PCR. These results suggest the importance of caspase 3 during the apoptotic process of mesothelioma cells and indicate that epirubicin-induced apoptosis is independent of the mitochondrial pathway.

Glioma cells under hypoxic conditions block the brain microvascular endothelial cell death induced by serum starvation

Angiogenesis is one of essential components for the growth of neoplasms, including malignant gliomas. However, tumor vascularization is often poorly organized and marginally functional due to tumor structural abnormalities, inducing regional or temporal hypoxic conditions and nutritional shortages in tumor tissues. We investigated how during angiogenesis migrating endothelial cells survive in these hypoxic and reduced nutritional conditions. Human brain microvascular endothelial cells (HBMECs) underwent apoptosis and necrosis after serum withdrawal. This endothelial cell death was blocked by recombinant VEGF protein or the culture medium of U251 glioma cells exposed to hypoxia (H-CM). Hypoxic treatment increased vascular endothelial growth factor (VEGF) and tumor necrosis factor alpha (TNF-alpha) expression in U251 glioma cells. H-CM activated nuclear factor-kappaB (NFkappaB) protein and increased the gene expression of antiapoptotic factors including Bcl-2, Bcl-X(L), survivin and X-chromosome-linked inhibitor of apoptosis protein (XIAP) in endothelial cells. The survival activity of H-CM for endothelial cells was abolished by two kinds of VEGF inhibitors {Cyclopeptidic VEGF inhibitor and a VEGF receptor tyrosine kinase inhibitor (4-[(4'-chloro-2'-fluoro) phenylamino]-6, 7-dimethoxyquinazoline)} or NFkappaB inhibitors (ALLN and BAY 11-7082). These VEGF inhibitors did not block the activation of NFkappaB induced by H-CM in endothelial cells. On the contrary, TNF-alpha antagonist WP9QY enhanced the survival activity of H-CM for endothelial cells and blocked NFkappaB activation induced by H-CM under serum-starved conditions. Taken together, our data suggest that both the secretion of VEGF from glioma cells and activation of NFkappaB in endothelial cells induced by TNF-alpha are necessary for endothelial cell survival as they increase the expression of antiapoptotic genes in endothelial cells under conditions of serum starvation. These pathways may be one of the mechanisms by which angiogenesis is maintained in glioma tissues.

Clinical significance of apoptotic index in non-small cell lung cancer: correlation with p53, mdm2, pRb and p21WAF1/CIP1 protein expression

PURPOSE

The aim of this study was to assess the prognostic relevance of apoptotic index (AI), considered alone or together with expression of several proteins controlling G1 check point (p53, mdm2, pRb and p21WAF1/CIP1) in non-small cell lung cancer (NSCLC) patients.

METHODS

Study group included 50 NSCLC patients who underwent curative pulmonary resection. Apoptosis was detected with the use of TUNEL technique and AI was defined as the number of apoptotic cells per 1,000 tumor cells. The expression of p53, mdm2, pRb and p21WAF1/CIP1 was assessed immunohistochemically.

RESULTS

The mean and median AI calculated for all 50 patients was 14 and 9, respectively. Patients with lower (<14) and higher (> or =14) AI constituted 35 (70%) and 15 (30%) of cases, respectively. AI was not correlated with patient clinical characteristics, and expression of p53, pRb and p21WAF1/CIP1 . However, lower AI was correlated with over-expression of mdm2 protein (P=0.04). Median survival for patients with lower and higher AI was 43 months and 22 months, respectively, and 5-year survival probability-60 and 25%, respectively (P=0.03). In multivariate analysis, the only variable associated with shortened survival was AI (P=0.03, HR=2.9, 95% CI 1.95-3.86).

CONCLUSIONS

These results suggest that AI correlates with mdm2 protein expression and influences survival in NSCLC.

Prognostic significance of apoptosis in medulloblastoma

Since apoptosis is a major contributor to cell loss in medulloblastoma, either spontaneous or induced by radiation and chemotherapy, the apoptotic rate in resection specimens could have prognostic significance. We analysed the apoptotic rate in 58 medulloblastoma resection specimens using an antibody against cleaved caspase 3, a specific marker of apoptotic cell death, and tested its possible prognostic significance. The apoptotic rate varied considerably among medulloblastomas (0.1-25.9%, median 1.1%). Apoptotic cells were relatively evenly distributed in 39 cases, while in 19 cases, an uneven distribution with foci of an increased number of apoptotic cells and their clustering was observed. Clusters of apoptotic cells were found around necrotic areas, while necrotic cells were caspase 3 negative. The apoptotic rate was higher in medulloblastomas with CSF dissemination, tended to be higher in desmoplastic medulloblastomas, but there was no association with age group and sex. In the univariate analysis of overall survival, the apoptotic rate had no prognostic value. The variation in apoptotic rate among medulloblastomas is very likely predominantly associated with variations in tumour microenvironment, as supported by apoptotic cell clustering and rimming around necrotic areas. The apoptotic rate in medulloblastoma resection specimens does not seem to be of prognostic value.

Survivin expression is regulated by an epigenetic mechanism for DMBA-induced hamster buccal-pouch squamous-cell carcinomas

Apoptosis, also known as programmed cell death, is regulated by a number of inhibitory or stimulatory factors. In addition to the pro- and anti-apoptotic Bcl-2 family proteins, there is also a family of inhibitors of apoptosis protein (IAP). Survivin, a member of this IAP family, is selectively upregulated in most tumours. The objective of the present study was, therefore, to investigate the protein and mRNA expression of survivin, as well as the methylation status of the CpG sites in exon 1 of the survivin gene for 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal-pouch squamous-cell carcinomas. Immunohistochemical analysis for protein expression, RT-PCR for mRNA expression, and a PCR-based methylation assay were performed on 26 samples of hamster buccal pouches. The total study population was assigned into either one experimental group (15-week DMBA treatment; n=13) or two control groups (untreated: n=6; mineral-oil treated n=7). Cytoplasmic staining of survivin protein and mRNA were detected in all of the hamster buccal-pouch tissue specimens treated with DMBA, whereas neither survivin protein nor survivin mRNA were noted for all of the untreated and mineral oil-treated hamster buccal-pouch tissue specimens. Furthermore, all the untreated and mineral-oil treated samples had a survivin-methylated allele, whereas the DMBA-treated cancerous tissues showed no evidence of survivin methylation. The results suggest that survivin may play an important role in DMBA-induced hamster buccal-pouch carcinomas, and that the gene expression may be modulated by an epigenetic mechanism.

Death-associated protein kinase (DAP kinase) alteration in soft tissue leiomyosarcoma: Promoter methylation or homozygous deletion is associated with a loss of DAP kinase expression

The death-associated protein kinase (DAP kinase) was initially identified as a positive mediator of programmed cell death induced by interferon-gamma. To investigate the potential role and the alteration of the DAP kinase gene in soft tissue leiomyosarcoma (LMS), we first searched for homozygous deletion and promoter hypermethylation in 45 LMSs for which genomic DNA was available, using differential PCR and methylation-specific PCR, respectively. Promoter methylation was recognized in 10 of 45 cases (22%), and homozygous deletion was detected in 3 of 45 cases (7%). p53 mutation was detected in 11 of 45 LMS cases (24%). Cases with DAP kinase alteration or p53 mutation showed a close correlation with high French Federation of Cancer Centers grade or with poor prognosis (P = 0.0244, P = 0.0491, respectively). Next, to determine that DAP kinase promoter methylation or homozygous deletion is involved in the down-regulation of DAP kinase expression, we examined the expression of DAP kinase protein by immunohistochemistry. Decreased expression of DAP kinase protein was recognized in 13 of 45 LMS cases (29%). Seven of 13 cases (54%) with decreased expression of DAP kinase protein revealed promoter methylation or homozygous deletion of DAP kinase, and the methylation status or homozygous deletion of its gene showed a close correlation with decreased DAP kinase expression (P = 0.0300). In conclusion, although DAP kinase alteration was relatively rare, DAP kinase alteration and/or p53 mutation may associate with tumor progression in soft-tissue LMSs. Furthermore, although further detailed analyses are necessary, promoter methylation or homozygous deletion status of DAP kinase may present a major alternative mechanism of a loss of or decrease in DAP kinase expression.

Neoadjuvant radiochemotherapy of oral cavity and oropharyngeal cancer: evaluation of tumor response by CT differs from histopathologic response assessment in a significant fraction of patients

BACKGROUND

Our aim was to compare and assess the predictive value of CT and histopathologic grading of tumor regression at primary tumor sites in patients with squamous cell carcinoma of the oral cavity and oropharynx after neoadjuvant (preoperative) radiochemotherapy (RCT).

METHODS

We investigated 55 patients with carcinomas of the oral cavity and oropharynx who underwent RCT before curative surgery. Two blinded observers measured RCT-induced reduction of tumor volume in pretherapeutic and posttherapeutic CT scans. Volume changes were compared with histopathologic findings obtained at surgery.

RESULTS

Histopathologic response evaluation revealed 31 complete remissions, 12 cases of partial response, and 12 nonresponders. We performed a logistic regression analysis to evaluate whether measured volume reduction could predict the likelihood of belonging to a certain response group. Taken together, we found 35 correct, 12 false-negative, and seven false-positive predictions.

CONCLUSIONS

The extent of remission as assessed by CT scans 4 to 5 weeks after completion of neoadjuvant RCT leads to false predictions in a significant percentage of patients.

Nucleosomes Bind Fibroblast Growth Factor-2 for Increased Angiogenesis In vitro and In vivo

Solid tumors often display sites of necrosis near regions of angiogenesis in vivo. As tumor cell necrosis would result in the release of nucleosomes into the extracellular environment, we explored the potential role of nucleosomes in the promotion of angiogenesis. Data indicate that nucleosomes acted similar to heparin and bound to several heparin-binding, proangiogenic factors [i.e., fibroblast growth factor (FGF)-1, FGF-2, vascular endothelial growth factor, and transforming growth factor-β1]. Nucleosomes modestly enhanced FGF-2 growth of human umbilical vein endothelial cells when grown in restricted media as well as increased human umbilical vein endothelial cell migration and primitive blood vessel tube formation in vitro. On s.c. injection in mice, nucleosomes aided FGF-2 in promoting angiogenesis. These results suggest that nucleosomes released from dying tumor cells aid in the formation of blood vessels and may provide a novel means by which tumor cells increase angiogenesis.

Proliferation to apoptosis ratio as a prognostic marker in adenocarcinoma of uterine cervix

OBJECTIVES

To determine the Mitotic Index (MI), Apoptotic Index (AI), the ratio of the two indices (MI/AI) in normal endocervical glands, adenocarcinoma in situ (AIS) and invasive adenocarcinoma of cervix, and to evaluate the relationship among these indices with various clinicopathological features.

METHODS

The MI, AI and MI/AI ratio in cervical adenocarcinoma were evaluated based on: (1) cell morphology in hematoxylin and eosin-stained sections; (2) immunohistochemical study for Ki67 antigen and terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL). Eighty cases of invasive adenocarcinoma and eighteen cases of adenocarcinoma in situ (AIS) adjacent to invasive adenocarcinoma were included. Adjacent normal endocervical epithelium in 26 cases of adenocarcinoma was included as control.

RESULTS

The MI, AI and MI/AI in normal endocervical glands, AIS and invasive carcinomas showed statistically significant differences (P<0.001). A significant positive correlation was found between AI and MI, as assessed by morphological features (P<0.001) and immunohistochemistry (P=0.006). The MI/AI ratio, determined by morphology, significantly correlated with staging (P=0.023) and survival (P=0.0045). Multivariate survival analysis showed that both MI/AI ratio determined by morphology (P<0.001) and stage of tumor (P=0.03) had independent prognostic value in invasive adenocarcinoma.

CONCLUSIONS

Tumor proliferation significantly correlated with apoptotic activity in cervical adenocarcinoma. The MI/AI ratio was an independent prognostic factor associated with patient survival. Histological determination of MI/AI ratio proved to be an economical and potentially useful adjunct in predicting clinical outcome of patients with cervical adenocarcinoma.

Expression of survivin and X chromosome-linked inhibitor of apoptosis protein in ameloblastomas

To clarify the role of apoptosis in oncogenesis and cytodifferentiation of odontogenic epithelium, expression of survivin and X chromosome-linked inhibitor of apoptosis protein (XIAP), inhibitor of apoptosis protein (IAP) family proteins, was examined in tooth germs and in benign and malignant ameloblastomas by means of immunohistochemistry and reverse-transcription polymerase chain reaction. Immunoreactivity for survivin and XIAP was detected in developing and neoplastic odontogenic epithelium. In tooth germs, survivin expression was evident in inner enamel epithelium. Follicular, plexiform and metastasizing ameloblastomas showed survivin reactivity chiefly in neoplastic cells neighboring the basement membrane, and most neoplastic cells in basal cell and desmoplastic ameloblastomas and ameloblastic carcinomas were positive for survivin. Survivin mRNA levels were slightly higher in ameloblastomas than in tooth germs, suggesting that elevation of survivin expression might be involved in oncogenesis of odontogenic epithelium. Immunoreactivity for XIAP was detected in most odontogenic epithelial cells in tooth germs and in benign and malignant ameloblastomas, and XIAP mRNA levels were significantly higher in follicular ameloblastomas than in plexiform ameloblastomas. The expression of survivin and XIAP in odontogenic tissues suggests that these IAP family proteins contribute to the biological properties of ameloblastomas, such as cell survival, proliferation, differentiation and tissue structuring, as well as to cellular regulation during tooth development.

Expression of the pro-apoptotic protein ARTS in astrocytic tumors

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Apoptosis, Proliferation, and Expression of p53 and bcl-2 in Endocervical Glandular Intraepithelial Lesions and Invasive Endocervical Adenocarcinoma

We evaluated apoptosis, proliferation, and p53 and bcl-2 expression in a spectrum of intraepithelial and invasive endocervical glandular lesions currently recognized by the World Health Organization as adenocarcinoma in situ, lesions with atypia "less than adenocarcinoma in situ" (endocervical glandular dysplasia and endocervical glandular atypia), and invasive adenocarcinoma. Aside from nuclear atypia, increased mitotic activity and apoptosis are consistent and closely correlated morphologic features of endocervical adenocarcinoma in situ. Apoptotic bodies and mitotic figures were counted in 32 examples of normal endocervical glands, 35 of endocervical glandular atypia, 30 of endocervical glandular dysplasia, 34 of adenocarcinoma in situ, and 30 of invasive adenocarcinoma. These results were correlated with immunohistochemical staining for MIB1, bcl-2, and p53 performed on 20 examples of each. Mitotic counts, p53 expression, and bcl-2 expression all increased significantly and in proportion to the degree of atypia in the spectrum of endocervical lesions. Apoptotic body counts and MIB1 expression also increased significantly with increasing atypia, but showed higher levels in adenocarcinoma in situ than in invasive adenocarcinoma. Apoptosis correlates with proliferation as measured by mitotic counts and MIB1, and also with p53 and bcl-2 expression. Apoptosis appears to be an important mechanism in the pathogenesis of endocervical glandular lesions and may be useful as an aid in their evaluation and diagnosis.

p53, cellular proliferation, and apoptosis-related factors in thymic neuroendocrine tumors

Thymic neuroendocrine tumors are biologically aggressive neoplasms with extensive local invasion and high mortality. Although various markers of cellular proliferation and apoptosis have correlated with degrees of tumor differentiation in pulmonary neuroendocrine neoplasms, they have not been systematically studied in thymic neuroendocrine tumors. We immunostained 21 cases of thymic neuroendocrine tumors for p53, MIB-1, and the apoptosis-related markers Bcl-2, Bcl-x, and Bax. By histological classification the cases were low-grade (nine cases), intermediate-grade (eight cases), and high-grade (four cases) thymic neuroendocrine tumors. p53 was expressed in five cases: 1/9 low grade, 3/8 intermediate grade, and 2/4 high grade. The mean cellular proliferation (MIB-1) was 7.1% (range 2-12%) in low-grade thymic neuroendocrine tumors, 6.1% (range 2-15%) in intermediate-grade thymic neuroendocrine tumors, and 34.2% (range 2-80%) in high-grade thymic neuroendocrine tumors. Bcl-2 was expressed in 16 cases: 7/9 low grade, 5/8 intermediate grade, and 4/4 high grade. Bcl-x was expressed in 16 cases: 7/9 low grade, 6/8 intermediate grade, and 3/4 high grade. Bax was expressed in 13 cases: 5/9 low grade, 4/8 intermediate grade, and 4/4 high grade. The presence of mutant p53 in the tumor was associated with a statistically significant decreased mean survival (P<0.05). In contrast, either by positive or negative staining or by the score technique (staining intensity x percentage of cells staining), the presence of Bcl-x was associated with an increased mean survival (P<0.05). Finally, a Bcl-x : Bax ratio >or=1 was also associated with an increased mean survival, as compared to a Bcl-x : Bax ratio >or=1 (P<0.05). Our study shows that p53 expression and certain apoptosis markers correlate with survival. The expression of these markers may account for differences in biological behavior.

The combination of calmodulin antagonists and interferon-gamma induces apoptosis through caspase-dependent and -independent pathways in cholangiocarcinoma cells

Calmodulin (CaM) antagonists have been shown to inhibit tumor cell invasion and metastasis and to induce apoptosis in various tumor models, but the molecular mechanism of CaM antagonist-mediated apoptosis is poorly understood. Here, we demonstrate that interferon (IFN)-gamma induces susceptibility to CaM antagonist-mediated apoptosis in human cholangiocarcinoma cells weakly expressing Fas (Fas-low cells). During CaM antagonist-mediated apoptosis in IFN-gamma-pretreated Fas-low cells, cleavage of caspases-8, -9, and -3 and Bid, release of cytochrome c from the mitochondria and an increase in the free cytosolic calcium concentration were observed. CaM antagonists also caused depolarization of the mitochondrial membrane independent of caspase activation. Although a broad-range caspase inhibitor partially blocked CaM antagonist-mediated apoptosis, the neutralizing Fas antibody had no effect, suggesting that CaM antagonist-mediated apoptosis does not require interaction between CaM antagonists and surface Fas. CaM antagonists induce apoptosis via mechanisms other than inhibition of CaM-dependent protein kinase II and calcineurin, as their inhibitors, KN93 and cyclosporine A, had no effect on apoptosis. Taken together, these results indicate that CaM antagonists induce apoptosis in both caspase-dependent and -independent manners, and that susceptibility to CaM antagonists is modulated by IFN-gamma. The combination of IFN-gamma and CaM antagonists, including tamoxifen, may be a potential therapeutic modality for cholangiocarcinoma and possibly other malignancies.