Interrelationship between Protein Phosphatase-2A and Cytoskeletal Architecture during the Endothelial Cell Response to Soluble Products Produced by Human Head and Neck Cancer

Tumor neovascularization is necessary for the progressive development of all solid tumors, including head and neck squamous cell carcinomas (HNSCCs). The angiogenic process includes increased endothelial cell motility. Our prior studies have shown the importance of protein phos-phatase-2A (PP-2A) in restricting endothelial cell motility. Because motility is regulated by the polymerization/depolymerization of the cellular cytoskeleton, the present study defined the interrelationship between PP-2A and the cytoskeleton during endothelial cell responses to HNSCC-derived angiogenic factors. PP-2A was shown to colocalize with microtubules of unstimulated endothelial cells. However, exposure to HNSCC-derived products resulted in a more diffuse distribution of PP-2A staining and a loss of filamentous tubulin. The feasibility of pharmacologically preventing this cytoskeletal disorganization as a means of blocking tumor-induced angiogenesis was tested. This was accomplished by use of 1α,25-dihydroxyvitamin D3[1,25 (OH)2D3] and all- trans-retinoic acid to indirectly stimulate PP-2A activity through their capacity to elevated intracellular levels of the second messenger ceramide. Pretreatment of endothelial cells with either 1,25(OH)2D3or retinoic acid prevented the cytoskeletal disorganization that otherwise occurs in endothelial cells on exposure to HNSCC-derived products. These studies support the feasibility of using elevation of PP-2A to prevent the mor-phogenic component of the angiogenic process that is stimulated by HNSCC-derived factors.

Morphological differences between circulating tumor cells from prostate cancer patients and cultured prostate cancer cells

Circulating tumor cell (CTC) enumeration promises to be an important predictor of clinical outcome for a range of cancers. Established CTC enumeration methods primarily rely on affinity capture of cell surface antigens, and have been criticized for underestimation of CTC numbers due to antigenic bias. Emerging CTC capture strategies typically distinguish these cells based on their assumed biomechanical characteristics, which are often validated using cultured cancer cells. In this study, we developed a software tool to investigate the morphological properties of CTCs from patients with castrate resistant prostate cancer and cultured prostate cancer cells in order to establish whether the latter is an appropriate model for the former. We isolated both CTCs and cultured cancer cells from whole blood using the CellSearch® system and examined various cytomorphological characteristics. In contrast with cultured cancer cells, CTCs enriched by CellSearch® system were found to have significantly smaller size, larger nuclear-cytoplasmic ratio, and more elongated shape. These CTCs were also found to exhibit significantly more variability than cultured cancer cells in nuclear-cytoplasmic ratio and shape profile.

Expression of multidrug resistance (MDR) proteins andin vitrodrug resistance in acute leukemias

The expression of the multidrug resistance (MDR) proteins may influence the outcome of treatment in patients with acute leukemia. The aim of this study was to determine the IC50 of cytotoxic drugs (cytosine arabinoside, ara-C and daunorubicin, dnr) using the in vitro 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)2H-tetrazolium, inner salt (MTS) assay method. A total of 82 newly diagnosed acute leukemia cases (43 adult myeloid leukaemia, AML cases and 39 acute lymphoblastic leukaemia, ALL cases) and 16 relapsed cases (8 AML cases and 8 ALL cases) were studied. The MTS assay was performed using two cytotoxic drugs, dnr and ara-C. Cells were incubated with different concentrations of drugs for 4 days and the IC50 was extrapolated from the viability curve. In newly diagnosed cases, we found that childhood ALL samples showed higher IC50 values of dnr (0.040 +/- 2.320) compared to adult AML samples (0.021 +/- 0.158). In contrast, newly diagnosed adult AML samples showed higher IC50 values of ara-C (0.157 +/- 0.529) compared to childhood ALL samples (0.100 +/- 2.350). In relapsed cases, two samples of childhood ALL showed IC50 values of dnr (0.910 +/- 1.760) and ara-C (1.310 +/- 2.390), which was higher compared to childhood AML samples (0.129 +/- 0.214 and 0.210 +/- 0.003, respectively). However, there was no correlation between IC50 values of these drugs tested with clinical outcome. In conclusion, we found that MTS assay is an easy, rapid and non laborious method to study in vitro drug resistance in acute leukaemia cases.

Phenotypic changes associated with exogenous expression of p16INK4a in human glioma cells

The tumor suppressor p16/CDKN2A/INK4a gene is frequently mutated, mostly by homozygous deletions in high-grade gliomas. Although the p16 protein suppresses cell proliferation primarily through inhibition of cell-cycle progression at the G1 phase, other phenotypic changes in glioma cells associated with p16INK4a alterations have not been fully described. To determine the roles of p16 alterations in glioma formation, we have established ecdysone-driven inducible p16 expression in the human glioblastoma cell line CL-4, which were derived from p16-null U87MG cells. Here we show that exogenous p16 expression in CL-4 cells results in morphological changes, with large and flattened cytoplasm, which are associated with increased formation of cytoplasmic actin-stress fibers and vinculin accumulation in the focal adhesion contacts. Adhesion of CL-4 cells to extracellular matrix proteins, such as laminin, fibronectin, and type IV collagen, significantly increased upon exogenous p16 expression, which correlated with increased expression of integrin alpha5 and alphav. Expression of a small GTP-binding protein, Rac, also decreased. Following epidermal growth factor stimulation, phosphorylation of MAP kinases ERK1 and 2 and induction of an early immediate gene product, c-Fos, were significantly reduced in CL-4 cells with p16 expression. These results suggest that the tumor suppressor p16 may exert its antitumor effects through modulation of multiple aspects of glioblastoma phenotypes, including proliferation, invasiveness, and responsiveness to extracellular growth stimuli.

Ultrastructural changes in tumor cells treated with liposomal forms of anticancer drugs

AIM

To determine the main ultrastructural changes in MCF-7 sublines sensitive and resistant to cytotoxic action of anticancer drugs, resulting from the treatment with conventional and liposomal forms of cisplatin and doxorubicin.

METHODS

Electron microscopy, light microscopy, MTT-test.

RESULTS

It has been shown that the phenomenon of drug resistance is associated with complication of ultrastructural organization of cells and more high differentiation by the main cytomorphologic characteristics which promote their resistance to cytotoxic action of anticancer preparations. Cytoarchitectonics of all resistant cells possesses common patterns and doesn't depend on the particular drugs toward which the resistance has been developed. It has been shown that the cells of the parental form MCF-7 line are more sensitive to cytotoxic action of doxorubicin than to cisplatin. Liposomal forms of anticancer drugs used at the same concentrations that the conventional ones, especially that of doxorubicin, caused more expressed alterations in ultrastructural organization of cells of all studied sublines with dominance of apoptotic processes.

CONCLUSION

Evaluating an effect of equal concentrations of cisplatin and doxorubicin in conventional and liposomal forms, one may conclude on higher cytotoxic action of doxorubicin vs. cisplatin that is expressed in a wider spectrum of ultrastructural changes of cell architectonics in different sublines of MCF-7 cells and higher rate of apoptosis.

Annulate Lamellae in a Large Cell Lung Carcinoma Cell Line with High Expression of Tyrosine Kinase Receptor and Proto-Oncogenes

The morphology, karyotype, in vitro growth properties, and expression of tyrosine kinase receptors and proto-oncogenes are reported for a newly established large cell undifferentiated lung carcinoma cell line (RVH-6849). The results were analyzed concomitantly with those for two well-established cell lines from an adenocarcinoma of the lung (A549) and a squamous cell carcinoma (A431). All three cell lines demonstrated common ultrastructural features of epithelial cells, but only RVH-6849 had frequent aggregates of centrioles and annulate lamellae (AL) and was polyploid, having five to seven copies of chromosome 7 by karyotype analysis. All three cell lines expressed transforming growth factor alpha (TGF-alpha), epidermal growth factor receptor (EGFR), c-erb B-2, and c-met genes. RVH-6849 cells, however, expressed the most messenger RNA (mRNA) for TGF-alpha, c-erb B-2, and c-met. Only EGFR mRNA was expressed more in the other two cell lines, especially in A431 cells. AL represent an exaggerated form of the nuclear membrane-pore complex that is found in actively proliferating cells such as germ and some neoplastic cells. AL are suspected to be involved in the deposition or processing of mRNA: The enhanced coexpression of AL and mRNAs of three tyrosine kinase-containing receptors in RVH-6849 cells may represent such a relationship.

Ro60 and La ribonucleoproteins become self-aggregated by cell stress

Ro and La antigens are of clinical interest in subacute cutaneous lupus erythematosus because skin lesions appear after UV irradiation, which induces the translocation of intracellular Ro and La ribonucleoproteins and trigger autoantibody production. Present studies address the question whether cellular stressors modify molecular characteristics and distribution of Ro60 and La proteins. To accomplish our goal HEp-2 cells were stressed by heat and UV irradiation and Ro and La expression was studied by indirect immunofluorescence and Western blot and crossed-immunoprecipitation using monoclonal anti-Ro/La or anti-HSP70 linked to CNBr-Sepharose 4B. Results of present studies confirm that Ro60 and La were located in the nuclei of non stressed cells; however under stress, both ribonucleoproteins were redistributed within cytoplasm and nucleoplasm, interestingly the stress induces self aggregation of both ribonucleoproteins, as demonstrated the Western blot assays. Ro and La proteins interact with the cytoskeleton protein via HSP70. In conclusion, the cell stress redistributes Ro and La proteins whiting nucleo-cytoplasmic compartments. This redistribution is accompanied by self aggregation of Ro and La which became associated with HSP70. Finally, the cell stress is an important factor for antigenic redistribution.

Comprehensive genetic characterization of CLL: a study on 506 cases analysed with chromosome banding analysis, interphase FISH, IgVH status and immunophenotyping

In CLL data from chromosome banding analysis (CBA) have been scarce due to the low proliferative activity of CLL cells in vitro. We improved the cultivation technique using an immunostimulatory CpG-oligonucleotide DSP30 and IL-2. A total of 506 CLL samples were analysed with CBA and interphase FISH using probes for the detection of trisomy 12, IgH rearrangements and deletions of 6q21, 11q22.3 (ATM), 13q14 (D13S25 and D13S319) and 17p13 (TP53). A total of 500 of 506 (98.8%) cases were successfully stimulated for metaphase generation and are subject to this study. Aberrations were detected in 415 of 500 (83.0%) cases by CBA and in 392 of 500 (78.4%) cases by FISH. CBA detected 832 abnormalities and FISH only 502. Therefore, CBA offers important information in addition to FISH. (1) CLL is characterized mainly by genomic imbalances and reciprocal translocations are rare. (2) A subgroup with complex aberrant karyotype (16.4%) is identified which is associated with an unmutated IgV(H) status and CD38 expression (P=0.034 and 0.02, respectively). (3) Additional abnormalities are detectable providing new biological insights into different CLL subclasses revealing a much more heterogeneous pattern of cytogenetic abnormalities as assumed so far based on FISH data only. Therefore, prospective clinical trials should evaluate the prognostic impact of newly available CBA data.

Variable pressure and environmental scanning electron microscopy: imaging of biological samples

The use of elevated gas pressures in the sample chamber of a scanning electron microscope (i.e., variable pressure SEM, or VPSEM) together with specialized electron detectors create imaging conditions that allow biological samples to be examined without any preparation. Specific operating conditions of elevated pressures combined with sample cooling (usually restricted to the environmental SEM range) can allow hydrated samples to be maintained in a pristine state for long periods of time. Dynamic processes also can be easily observed. A wider range of detector options and imaging parameters introduce greater complexity to the VPSEM operation than is present in routine SEM. The current instrumentation with field emission electron sources has nanometer-scale beam resolution (approx 1 nm) and low-voltage beam capability (0.1 kV). However, under the more extreme variable pressure conditions, useful biological sample information can be achieved by skilled operators at image resolutions to 2 to 4 nm and with primary electron beam voltages down to 1.0 kV. Imaging relating to electron charge behavior in some biological samples, generally referred to as charge contrast imaging, provides information unique to this VPSEM and environmental SEM that closely relates to luminescence imaged by confocal microscopy.

Artificially introduced aneuploid chromosomes assume a conserved position in colon cancer cells

Background

Chromosomal aneuploidy is a defining feature of carcinomas. For instance, in colon cancer, an additional copy of Chromosome 7 is not only observed in early pre-malignant polyps, but is faithfully maintained throughout progression to metastasis. These copy number changes show a positive correlation with average transcript levels of resident genes. An independent line of research has also established that specific chromosomes occupy a well conserved 3D position within the interphase nucleus.

Methodology/Principal Findings

We investigated whether cancer-specific aneuploid chromosomes assume a 3D-position similar to that of its endogenous homologues, which would suggest a possible correlation with transcriptional activity. Using 3D-FISH and confocal laser scanning microscopy, we show that Chromosomes 7, 18, or 19 introduced via microcell-mediated chromosome transfer into the parental diploid colon cancer cell line DLD-1 maintain their conserved position in the interphase nucleus.

Conclusions

Our data is therefore consistent with the model that each chromosome has an associated zip code (possibly gene density) that determines its nuclear localization. Whether the nuclear localization determines or is determined by the transcriptional activity of resident genes has yet to be ascertained.

Regulation and characterization of the polarity of cells embedded in a reconstructed basement matrix using a three-dimensional micro-culture system

Three cell lines, that is, the human breast cancer cell line (MCF-7) and the human mammary epithelial cell line (S-1) and its malignant form (T4-2) were embedded in a reconstituted basement membrane (Matrigel) that had 20-nL pyramid-shaped silicon microstructures. The proliferative behavior of the MCF-7 cells was dependent on the surrounding conditions (2-D, collagen gel, or Matrigel), whereas the respiratory activity of a single cell (F(c)) was almost identical under different culture conditions. The F(c) value changed with cellular polarity. The F(c) value for the S-1 cells was observed to decrease slightly, whereas that of the T4-2 cells increased 2 days after cultivation in the microstructures within the Matrigel. However, when the T4-2 cells were cultured in the presence of tyrphostin AG 1478 (T4-2 tyr) to inhibit epidermal growth factor (EGF) signaling, the F(c) value decreased slightly and remained almost constant for an additional 1 week; this was similar to the behavior of the S-1 cells. Further, fluorescence images showed that the T4-2 tyr cells formed polar structures that were similar to those formed by the S-1 cells whereas the T4-2 cells did not form such structures. These results indicate that cellular polarity can be assessed by measuring cellular respiratory activity.

Evaluation of particulate systems supporting tumor cell fractions in a preventive vaccination against intracranial rat glioma

Object

Irradiated autologous tumor cells are commonly used as a source of antigens in antiglioma vaccinations to activate the immune system. As cell number is often a limiting factor in these cells’ preparation, the aim of the present study was to find a means that can lower the amount of cells required. Among strategies currently developed, adjuvant particulate systems offer a promising means to improve the antitumor immune response. In this study, the authors were interested in evaluating the role of particulate systems containing biodegradable microspheres that carry tumor cell fractions on their surfaces in the induction of a protective immunity in the 9L/Fischer 344 rat glioma model. The efficiency of these particulate systems was compared to that of irradiated 9L cells.

Methods

Particulate systems composed of poly(d,l-lactide-co-glycolide) (PLGA) microspheres that support 9L cell fractions on their surfaces (cell lysates or plasma membranes) or irradiated 9L cells alone were injected subcutaneously into the flanks of syngeneic Fischer 344 rats. Eighteen days later, the rats were intracranially injected with nonirradiated 9L cells. A study of survival in these animals and an analysis of the resulting immune response were then conducted.

For the same amount of protein (50 μg) injected, irradiated 9L cells provided long-term survival in 30% of animals, whereas 9L plasma membranes adsorbed onto PLGA microspheres provided long-term survival in 10% of animals and cell lysates adsorbed onto microspheres provided long-term survival in 0%. Accordingly, particulate systems induced a lower T helper cell Type 1 (Th1) peripheral immune response than irradiated 9L cells. However, greater secretion of Th1 cytokines was observed when particulate systems were used than when cell fractions separated from microspheres were used, indicating the adjuvant property of these particulate systems.

Conclusions

Particulate systems have adjuvant properties but are still less efficient than irradiated whole tumor cells for vaccinations. Encapsulation of an activating molecule in the microsphere will be the next developmental step in the search for efficient antiglioma vaccinations.

CLN3P, the Batten's disease protein, is a novel palmitoyl-protein Delta-9 desaturase

OBJECTIVE

Batten's disease, one of the most common recessively inherited, untreatable, neurodegenerative diseases of humans, is characterized by progressive neuronal loss and intraneuronal proteolipid storage. Although the gene for the disorder was cloned more than a decade ago, the function of the encoded protein, CLN3P, has not been defined thus far.

METHODS

Sequence analysis using the Pfam server identified a low stringency match to a fatty acid desaturase domain in the N-terminal sequence of CLN3P. We developed a fatty acid desaturase assay based on measurement of desaturase products by gas chromatography/mass spectrometry.

RESULTS

We show that CLN3P is a novel palmitoyl-protein Delta-9 desaturase, which converts membrane-associated palmitoylated proteins to their respective palmitoleated derivatives. We have further demonstrated that this palmitoyl-protein Delta-9 desaturase activity is deficient in cln3(-/-) mouse pancreas and is completely ablated in neuroblastoma cells by RNA inhibition.

INTERPRETATION

We propose that palmitoyl-protein desaturation defines a new mechanism of proteolipid modification, and that deficiency of this process leads to the signs and symptoms of Batten's disease.

Cationic long-chain ceramide LCL-30 induces cell death by mitochondrial targeting in SW403 cells

Ceramides are sphingolipid second messengers that are involved in the mediation of cell death. There is accumulating evidence that mitochondria play a central role in ceramide-derived toxicity. We designed a novel cationic long-chain ceramide [omega-pyridinium bromide D-erythro-C16-ceramide (LCL-30)] targeting negatively charged mitochondria. Our results show that LCL-30 is highly cytotoxic to SW403 cells (and other cancer cell lines) and preferentially accumulates in mitochondria, resulting in a decrease of the mitochondrial membrane potential, release of mitochondrial cytochrome c, and activation of caspase-3 and caspase-9. Ultrastructural analyses support the concept of mitochondrial selectivity. Interestingly, levels of endogenous mitochondrial C16-ceramide decreased by more than half, whereas levels of sphingosine-1-phosphate increased dramatically and selectively in mitochondria after administration of LCL-30, suggesting the presence of a mitochondrial sphingosine kinase. Of note, intracellular long-chain ceramide levels and sphingosine-1-phosphate remained unaffected in the cytosolic and extramitochondrial (nuclei/cellular membranes) cellular fractions. Furthermore, a synergistic effect of cotreatment of LCL-30 and doxorubicin was observed, which was not related to alterations in endogenous ceramide levels. Cationic long-chain pyridinium ceramides might be promising new drugs for cancer therapy through their mitochondrial preference.

Independent motile microplast formation correlates with glioma cell invasiveness

Diffuse brain invasion contributes to the poor prognosis for patients with gliomas. Analyzing glioma cell migration in vitro, we have demonstrated the spontaneous shedding of anucleate cell fragments that separate from glioma cell bodies and maintain viability from hours to days. Unlike previously described cell fragments that are released from cells as diffusible vectors, glioma cell fragments are independently motile. We used computerized time-lapse microscopy to characterize the formation of these independent motile microplasts (IMMPs) in human cell cultures derived from the most highly invasive glial tumor, glioblastoma. IMMPs were larger than previously described cell fragments, ranging in size from approximately 2% to nearly half of the area of their parent cells. Complex cell-like behaviors-including establishment of polarity, extension of lamellipodia and filopodia, and change in direction of movement-remained intact in IMMPs. The average direction and velocity of the IMMPs were indistinguishable from those of their parent cells. IMMPs formed at a significantly higher rate in glioma cell lines rendered more invasive by overexpression of invasion-related genes than in vector-transfected controls. The correlation with cell invasiveness indicates that IMMP formation may be related to the cell-invasive phenotype. Further investigation will determine whether IMMPs represent a novel addition to the growing list of viable cell fragments with biological relevance.

Morphology of mitochondrial permeability transition: morphometric volumetry in apoptotic cells

Here we report on the mitochondrial permeability transition (MPT), which refers to the morphology of mitochondria whose inner membrane has lost its selective permeability. In all types of apoptotic cells so far examined, we found outer mitochondrial membranes that had been ruptured. These mitochondria present a swollen matrix covered by an inner membrane herniating into the cytoplasm through the breached outer membrane. Similarly ruptured outer mitochondrial membranes have been reported in studies on mitochondrial fractions induced to undergo MPT, carried out by others. Our observations were made on five types of rat tissue cells and six different cultured cell lines in the early stages of apoptosis. Samples from the cell lines HL-60, HeLa, WEHI-164, and a special batch of PC-12 cells were subjected to various apoptogenic agents and analyzed morphometrically. Nonapoptotic companion cells with unaltered nuclear structure (CUNS) were also analyzed. The mitochondrial volume in microm(3) and the volume fraction of the cytoplasm occupied by mitochondria in cells with typical nuclear signs of apoptosis and also in CUNS were evaluated. The volume of the mitochondria with ruptured membrane represents at least 69% (47-89%) of the total mitochondrial volume of the apoptotic cells. Thus, a considerable fraction of the cellular mitochondrial mass is or was in the state of permeability transition and probably involved in enhancement of the apoptotic program. In all samples, a fraction of the cells with normal nuclei possessed mitochondria with breached outer membranes as described above. In these cells, MPT occurred before the appearance of the typical nuclear phenotype of the apoptotic cells.

Chromosomal radiosensitivity and low penetrance predisposition to cancer

This mini-review summarises studies in this Institute on the sensitivity of cells of patients with common cancers to the chromosome-damaging effects of ionising radiation, in the context of related studies. Using the 90th percentile of healthy controls (n >200) as the cut-off point between a normal and a sensitive response, 40% of patients with breast cancer (n = 166) were sensitive when cells were irradiated in the G2 phase of the cell cycle. Smaller studies showed that patients with colorectal, head and neck (at < 45 years) and childhood cancers also exhibited degrees of enhanced sensitivity, whereas cervical and lung cancer cases did not. Cells from breast and head and neck cases irradiated in G(0) also showed increased sensitivity. We propose that such elevated sensitivity is a marker of low penetrance predisposition to cancer. The strongest support for this hypothesis was our demonstration of the Mendelian heritability of chromosomal radiosensitivity in 95 family members of breast cancer cases. Challenges for the future include more heritability studies, identification of the underlying genetic determinants, assessment of the associated cancer risk (spontaneous and radiogenic) and population screening for cancer prevention strategies.

Spectral karyotyping indicates complex rearrangements in lung adenocarcinoma of nonsmokers

Adenocarcinoma (AdC) of the lung represents a common histologic subtype of non-small cell lung cancer. While there is a rising incidence of AdC in nonsmoking women, information on the cytogenetic changes involved has been minimal to date. In the present study, spectral karyotyping analysis uncovered the genome-wide chromosomal aberrations in two AdC tumors derived from women who were lifelong nonsmokers. Simple and complex structural rearrangements were indicated. A ploidy status of hypertetraploidy was suggested in both cases, with recurring derivative translocations involving chromosome arms 3q, 8q, 12q, 15q, 22q, and Xq.

Apoptosis in Hep2 cells treated with etoposide and colchicine

When malignant cells undergo apoptosis, they exhibit many distinct patterns of behavior, with blebbing being one of the most spectacular and mysterious features. Despite huge advancements in our understanding of cell death, the mechanisms of apoptosis associated blebbing have not been elucidated. In order to verify the putative involvement of actin and tubulin in this process, Hep2 cells were treated with a combination of etoposide (10 microg/ml) and colchicine (0.2 microg/ml) for 24 h. Blebbing was analyzed using immunofluorescence staining of actin and tubulin, and the course of apoptosis was followed by time-lapse videomicroscopy, immunofluorescence detection of caspase-3 and cytokeratin fragment 18. The results indicate that microfilaments (actin) and not microtubules (tubulin) are involved in blebbing of Hep2 cells. Furthermore, despite the different mechanisms by which both chemicals act, their combined effects are not additive, but rather eliminate each other.

Using the atomic force microscope to observe and study the ultrastructure of the living BIU-87 cells of the human bladder cancer

In this study, the ultrastructure of living BIU-87 cells of human bladder cancer was mapped using atomic force microscopy to reveal the dynamic change of single cancerous cell division. Simultaneously, the feasibility and functional reliability of the atomic force microscope (AFM) were established and a laboratory model using AFM to study living cancerous cells was created. In this experiment, BIU-87 cells of human bladder cancer were cultured by conventional methods and grown in gelatin-treated dishes. A thermostat was used for preserving the cell's living temperature. Scanning of these cells using AFM was carried out in physiologic condition. The AFM images of the ultrastructure of living BIU-87 cells as well as those of the cell's membrane and cytoskeleton were very clear. The dynamic phenomenon of single cell division was observed. It was concluded that the AFM was able to observe and depict the ultrastructure of living cells of human bladder cancer directly and in real time. This experimental model is expected to play an important role in elucidating the cancerous mechanism of bladder normal cells at the atomic or nanometer level.

[Morphological and cytochemical properties of the human glioblastoma T98G cells during the monolayer culture]

The study was carried out with the aim of determination of morphological and cytochemical properties of human glioblastoma T98G cells in monolayer culture. Using light microscopic and immunocytochemical techniques, the glioblastoma cell line studied was shown to have low susceptibility to the effects of environmental factors and changes in culture conditions as well as high proliferative activity. All T98G cells were demonstrated to have positive nuclear reaction for p53 protein. An ability of T98G cells for spontaneous caspase 3-mediated apoptosis was shown using the antibodies against activated caspase 3. The data obtained suggest that glioblastoma T98G cell line could be used as a convenient model for testing the capacity of natural substances and of pharmaceutical agents that are being developed for the selective induction of caspase 3-mediated apoptosis.

Internalization of beta-amyloid causes downregulation of apolipoprotein E mRNA expression in neuroblastoma cells

Apolipoprotein (apo) E, like beta-amyloid (Abeta), is a key component of the senile plaques that characterize Alzheimer's disease (AD). Understanding how apoE participates in the formation of senile plaques is necessary to clarify the pathogenesis of AD; however, the mechanism remains unknown. In this study, we investigated the changes of cellular apoE and its mRNA level induced by addition of extracellular Abeta to neuroblastoma cells. The presence of > or = 1.0 micromol/L of Abeta induced a decrease of apoE mRNA expression and an increase in the immunofluorescence reactivity for intracellular apoE. Both Abeta and apoE were observed by electron-microscopy to be localized within lysosomes. The levels of intracellular apoE and its mRNA returned to the steady state time-dependently. These changes were attenuated by treatments with heparinase I or receptor-associated protein. These findings suggest that the internalized Abeta, along with cellular apoE, induces downregulation of apoE mRNA via a pathway possibly mediated by apoE receptors and heparin sulfate proteoglycans. A disorder of this physiological response could be linked to the development of AD.

Expression of HNFs and C/EBP alpha is correlated with immunocytochemical differentiation of cell lines derived from human hepatocellular carcinomas, hepatoblastomas and immortalized hepatocytes

Objective assessment of the differentiation grade of hepatocellular carcinomas (HCCs) is important for evaluation of the pathological diagnosis, prognosis and therapeutic treatment. Differentiation of hepatocytes is reflected by their expression of hepatic functional proteins in the mouse embryo, and liver-enriched transcription factors (LETFs) have been shown to regulate hepatic functional genes strictly. Previous reports demonstrated that the level of LETF expression is altered in HCC or preneoplastic nodules compared with noncancerous tissues. Therefore, LETF expression levels might be useful as a measure of HCC maturation. In this study, to clarify the correlation between the expression of LETFs and the differentiation grade of HCCs, we performed a quantitative analysis of the mRNA expressions of HNFs and C/EBP alpha using real-time reverse-transcription PCR and immunocytochemical analysis for hepatic functional proteins in twelve cell lines. Furthermore, we examined orthotopic transplantations of the HCC cell lines in C.B-17/Icrj-scid/scid mice and characterized the histologic and cytologic differentiation of the tumors that developed. Our results showed that comprehensive expressions of HNF-3beta, HNF-4 alpha, HNF-1 alpha, and C/EBP alpha were specific to HCCs with well-differentiated function and morphology. Furthermore, among these four transcription factors, HNF-4 alpha and HNF-1 alpha expressions showed synchronism and had a close relation with HCC differentiation. These in vitro results were confirmed in tumors developed in SCID mice in vivo. These findings suggested that HNF-4 alpha and HNF-1 alpha are useful markers to assess the degree of HCC differentiation, which we suggest could be evaluated objectively by the quantitative analysis of HNFs and C/EBP alpha in HCCs.

Role of PKC-delta activity in glutathione-depleted neuroblastoma cells

Protein kinases C (PKCs) are a family of isoenzymes sensitive to oxidative modifications and involved in the transduction signal pathways that regulate cell growth. As such, they can act as cellular sensors able to intercept intracellular redox changes and promote the primary adaptive cell response. In this study, we have demonstrated that PKC isoforms are specifically influenced by the amount of intracellular glutathione (GSH). The greatest GSH depletion is associated with a maximal reactive oxygen species (ROS) production and accompanied by an increase in the activity of the delta isoform and a concomitant inactivation of alpha. ROS generation induced early morphological changes in GSH-depleted neuroblastoma cells characterized, at the intracellular level, by the modulation of PKC-delta activity that was involved in the pathway leading to apoptosis. When cells were pretreated with rottlerin, their survival was improved by the ability of this compound to inhibit the activity of PKC-delta and to counteract ROS production. These results define a novel role of PKC-delta in the cell signaling pathway triggered by GSH loss normally associated with many neurodegenerative diseases and clinically employed in the treatment of neuroblastoma.

Sphingosylphosphorylcholine regulates keratin network architecture and visco-elastic properties of human cancer cells

Sphingosylphosphorylcholine (SPC) is a naturally occurring bioactive lipid that is present in high density lipoproteins (HDL) particles and found at increased levels in blood and malignant ascites of patients with ovarian cancer. Here, we show that incubation of human epithelial tumour cells with SPC induces a perinuclear reorganization of intact keratin 8-18 filaments. This effect is specific for SPC, largely independent of F-actin and microtubules, and is accompanied by keratin phosphorylation. In vivo visco-elastic probing of single cancer cells demonstrates that SPC increases cellular elasticity. Accordingly, SPC stimulates migration of cells through size-limited pores in a more potent manner than lysophosphatidic acid (LPA). LPA induces actin stress fibre formation, but does not reorganize keratins in cancer cells and hence increases cellular stiffness. We propose that reorganization of keratin by SPC may facilitate biological phenomena that require a high degree of elasticity, such as squeezing of cells through membranous pores during metastasis.

Visualization of early events in tumor formation of eGFP-transfected rat colon cancer cells in liver

Colon cancer preferentially metastasizes to the liver. To determine cellular backgrounds of this preference, we generated an enhanced green fluorescent protein (eGFP)-expressing rat adenocarcinoma cell line (CC531s) that forms metastases in rat liver after administration to the portal vein. Intravital videomicroscopy (IVVM) was used to visualize early events in the development of tumors in livers of live animals from the time of injection of the cancer cells up to 4 days afterward. Based on information obtained with IVVM, tissue areas were selected for further analysis using confocal laser scanning microscopy (CLSM), electron microscopy (EM), and electron tomography. It was shown that initial arrest of colon cancer cells in sinusoids of the liver was due to size restriction. Adhesion of cancer cells to endothelial cells was never found. Instead, endothelial cells retracted rapidly and interactions were observed only between cancer cells and hepatocytes. Tumors developed exclusively intravascularly during the first 4 days. In conclusion, initial steps in the classic metastatic cascade such as adhesion to endothelium and extravasation are not essential for colon cancer metastasis in liver.

Membrane type I matrix metalloproteinase usurps tumor growth control imposed by the three-dimensional extracellular matrix

Cancer cells are able to proliferate at accelerated rates within the confines of a three-dimensional (3D) extracellular matrix (ECM) that is rich in type I collagen. The mechanisms used by tumor cells to circumvent endogenous antigrowth signals have yet to be clearly defined. We find that the matrix metalloproteinase, MT1-MMP, confers tumor cells with a distinct 3D growth advantage in vitro and in vivo. The replicative advantage conferred by MT1-MMP requires pericellular proteolysis of the ECM, as proliferation is fully suppressed when tumor cells are suspended in 3D gels of protease-resistant collagen. In the absence of proteolysis, tumor cells embedded in physiologically relevant ECM matrices are trapped in a compact, spherical configuration and unable to undergo changes in cell shape or cytoskeletal reorganization required for 3D growth. These observations identify MT1-MMP as a tumor-derived growth factor that regulates proliferation by controlling cell geometry within the confines of the 3D ECM.

Asymmetric localization of flotillins/reggies in preassembled platforms confers inherent polarity to hematopoietic cells

Hematopoietic cells have long been defined as round, nonpolar cells that show uniform distribution of cell surface-associated molecules. However, recent analyses of the immunological synapse and the importance of lipid microdomains in signaling have shed new light on the aspect of lymphocyte polarization during the activation processes, but none of the molecules implicated so far in either the activation process or the microdomain residency are known to have a preferential localization in nonactivated cells. Chemical crosslinking and fluorescence resonance energy transfer methods have allowed the visualization of certain glycosylphosphatidylinositol-anchored proteins in lipid rafts but so far no microdomain resident protein has been shown to exist as visible stable platforms in the membrane. We report here that two lipid microdomain resident proteins, flotillins/reggies, form preassembled platforms in hematopoietic cells. These platforms recruit signaling molecules upon activation through lipid rafts. The preassembled platforms significantly differ from the canonical cholesterol-dependent "lipid rafts," as they are resistant to cholesterol-disrupting agents. Most evidence for the functional relevance of microdomains in living cells remains indirect. Using laser scanning confocal microscopy, we show that these proteins exist as stable, microscopically patent domains localizing asymmetrically to one pole of the cell. We present evidence that the asymmetric concentration of these microdomain resident proteins is built up during cytokinesis.

Proliferation, migration, and invasion of human glioma cells exposed to fractionated radiotherapy in vitro

Radiotherapy is a well established treatment for malignant gliomas. This study describes the migration, proliferation, and invasion behaviour of two human glioma cell lines (GaMg and U-87 Mg) grown as multicellular tumour spheroids after radiotherapy. Migration and proliferation studies were performed using conventional and accelerated fractionation up to 60 Gy and 59.4 Gy, respectively. A dose-dependent growth and migratory response to irradiation independent of the type of fractionation was observed. A coculture system in which tumour spheroids were confronted with foetal rat brain aggregates was used for invasion studies. Marked invasion of the glioma spheroids into the brain aggregates occurred with or without radiotherapy. For the GaMg cells, flow cytometric DNA histograms after treatment with 10 Gy and 40 Gy showed an accumulation of cells in the G2/M phase of the cell cycle. Radiotherapy inhibits tumour cell growth and migration, but the invasiveness of the remaining tumour cells seems to be unaffected.

Testing the "Go or Grow" hypothesis in human medulloblastoma cell lines in two and three dimensions

OBJECTIVE

The "Go or Grow" hypothesis proposes that cell division and cell migration are temporally exclusive events and that tumor cells defer cell division to migrate. The purpose of this study was to assess the Go or Grow hypothesis using medulloblastoma cell lines in directional migration and invasion assays in monolayer and three-dimensional cultures.

METHODS

Time-lapse videomicroscopy was used to continually monitor the directional migration, invasion, and mitosis of individual cells. The mitotic activity observed by time-lapse videomicroscopy was compared with staining for the proliferating cell nuclear antigen Ki-67.

RESULTS

A positive correlation exists between the migratory/invasive and mitotic activities of the four medulloblastoma cell lines studied. Within individual cell lines, however, migration and invasion distances are not influenced by the number of cell divisions. Time-lapse videomicroscopy and Ki-67 staining revealed similar trends in mitotic activity between migrating and nonmigrating cells within cell lines. Analysis of cell velocities before, after, and between cell divisions revealed an increase in cell velocity after cell divisions.

CONCLUSION

In the models studied, four medulloblastoma cell lines do not defer cell proliferation for migration across an uncoated surface or invasion of a Type I collagen matrix, contrary to the Go or Grow hypothesis. Migrating and invading cells continue to proliferate and migrate/invade a cell line-dependent distance irrespective of the number of divisions that take place. These findings emphasize the need to evaluate the effect of future therapies on both biological events and, if possible, to identify intracellular signaling proteins that negatively regulate medulloblastoma migration/invasion and proliferation.

Lovastatin, a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, induces apoptosis and differentiation in human anaplastic thyroid carcinoma cells

Although only 1% of differentiated thyroid cancers transform into anaplastic thyroid cancer, this disease is always fatal. Differentiation therapy may provide a new therapeutic approach to increasing the survival rate in such patients. 3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors are reported to promote cellular apoptosis and differentiation in many cancer cells; these effects are unrelated to lipid reduction. Recently, we found that TNFalpha induces cytomorphological differentiation in anaplastic thyroid cancer cells and increases thyroglobulin expression; however, TNF is cytotoxic for normal human tissue. The aim of this study was to determine whether lovastatin, an HMG-CoA reductase inhibitor, could induce apoptosis and differentiation in anaplastic thyroid cancer cells. Anaplastic thyroid cancer cells were treated with lovastatin, then examined for cellular apoptosis and cytomorphological differentiation by DNA fragmentation, phosphatidylserine externalization/flow cytometry, and electron microscopy. Thyroglobulin levels in the culture medium were also measured. Our results showed that at a higher dose (50 micro M), lovastatin induced apoptosis of anaplastic thyroid cancer cells, whereas at a lower dose (25 micro M), it promoted 3-dimensional cytomorphological differentiation. It also induced increased secretion of thyroglobulin by anaplastic cancer cells. Our results show that lovastatin not only induces apoptosis, but also promotes redifferentiation in anaplastic thyroid cancer cells, and suggest that it and other HMG-CoA reductase inhibitors merit further investigation as differentiation therapy for the treatment of anaplastic thyroid cancer.

Taccalonolides E and A: Plant-derived steroids with microtubule-stabilizing activity

During the course of a mechanism-based screening program designed to identify new microtubule-disrupting agents from natural products, we identified a crude extract from Tacca chantrieri that initiated Taxol-like microtubule bundling. Bioassay-directed purification of the extract yielded the highly oxygenated steroids taccalonolides E and A. The taccalonolides caused an increased density of cellular microtubules in interphase cells and the formation of thick bundles of microtubules similar to the effects of Taxol. Mitotic cells exhibited abnormal mitotic spindles containing three or more spindle poles. The taccalonolides were evaluated for antiproliferative effects in drug-sensitive and multidrug-resistant cell lines. The data indicate that taccalonolide E is slightly more potent than taccalonolide A in drug-sensitive cell lines and that both taccalonolides are effective inhibitors of cell proliferation. Both taccalonolides are poorer substrates for transport by P-glycoprotein than Taxol. The ability of the taccalonolides to circumvent mutations in the Taxol-binding region of beta-tubulin was examined using the PTX 10, PTX 22, and 1A9/A8 cell lines. The data suggest little cross-resistance of taccalonolide A as compared with Taxol, however, the data from the PTX 22 cell line indicate a 12-fold resistance to taccalonolide E, suggesting a potential overlap of binding sites. Characteristic of agents that disrupt microtubules, the taccalonolides caused G(2)-M accumulation, Bcl-2 phosphorylation, and initiation of apoptosis. The taccalonolides represent a novel class of plant-derived microtubule-stabilizers that differ structurally and biologically from other classes of microtubule-stabilizers.

Characterization of E-cadherin endocytosis in isolated MCF-7 and chinese hamster ovary cells: the initial fate of unbound E-cadherin

The endocytosis of E-cadherin has recently emerged as an important determinant of cadherin function with the potential to participate in remodeling adhesive contacts. In this study we focused on the initial fate of E-cadherin when it predominantly exists free on the cell surface prior to adhesive binding or incorporation into junctions. Surface-labeling techniques were used to define the endocytic itinerary of E-cadherin in MCF-7 cells and in Chinese hamster ovary cells stably expressing human E-cadherin. We found that in this experimental system E-cadherin entered a transferrin-negative compartment before transport to the early endosomal compartment, where it merged with classical clathrin-mediated uptake pathways. E-cadherin endocytosis was inhibited by mutant dynamin, but not by an Eps15 mutant that effectively blocked transferrin internalization. Furthermore, sustained signaling by the ARF6 GTPase appeared to trap endocytosed E-cadherin in large peripheral structures. We conclude that in isolated cells unbound E-cadherin on the cell surface is predominantly endocytosed by a clathrin-independent pathway resembling macropinocytotic internalization, which then fuses with the early endosomal system. Taken with earlier reports, this suggests the possibility that multiple pathways exist for E-cadherin entry into cells that are likely to reflect cell context and regulation.

Progesterone induces cellular differentiation in MDA-MB-231 breast cancer cells transfected with progesterone receptor complementary DNA

Progesterone is an important regulator of growth and differentiation in breast tissues. In this study, the effect of progesterone on cell differentiation was evaluated in the estrogen receptor-negative and progesterone receptor (PR)-negative MDA-MB-231 cell line which was transfected with PR-complementary DNA. Morphological changes were analyzed at the ultrastructural level by scanning and transmission electron microscopy. Progesterone-treated PR-transfected cells exhibited a more protracted and well spread morphology with an increase in organelles such as mitochondria and rough endoplasmic reticulum as compared to the rounded form of control vehicle (0.1% ethanol)-treated PR-transfected cells. Vehicle and progesterone-treated MDA-MB-231 cells transfected with the pSG5 plasmid (transfection control cells) had similar rounded morphology as control vehicle-treated PR-transfected cells. Immunofluorescence staining revealed that expression of E-cadherin, a differentiation marker, was more prominent in progesterone-treated cells. Expression of keratin and vimentin but not beta-catenin was up-regulated in progesterone treated cells when evaluated by immunoblotting. As signal transducers and activators of transcription (STAT) molecules have been implicated in mammary differentiation, we analyzed the expression of Stat 1, 3, 5a, and 5b proteins and found a significant up-regulation of the Stat 5b protein in progesterone-treated cells. We have provided in vitro evidence of the close association of PR with differentiation in breast cancer. It is likely that the Stat 5b protein may play a major role in progesterone-induced differentiation in breast cancer cells.

Transfection of MS-36 melanoma cells with gef gene inhibits proliferation and induces modulation of the cell cycle

The gef gene, found in Escherichia coli DNA, encodes a small (50 amino acids) protein which is related to cell-killing functions. We used the MS-36 melanoma cell line as an experimental model to examine the usefulness of the gef gene as a new strategy for cancer therapy. We transfected MS-36 cells using the pMAMneo vector, and induced gef gene expression with dexamethasone. This decreased the proliferation rate of MS-36TG by as much as 85% in comparison with MS-36 parental cells. The decrease in cell growth was accompanied with significant modifications of the cell cycle and morphology. The G1-phase gradually disappeared, with accumulation in the S-phase. However, studies with annexin V-FITC and 7-aminoactinomycin D failed to demonstrate induction of apoptosis. Morphological changes were an increase in cell size and the number of filopodia, and especially the appearance of pore-like alterations in the cell membrane which were not seen in parental cells. Our results demonstrate that the gef gene, a system independent of the administration of a prodrug, significantly reduces the proliferation of MS-36 cells. This gene may therefore be considered a new candidate for cancer gene therapy.

Same serial section correlative light and energy-filtered transmission electron microscopy

Correlative imaging of a specific cell with both the light microscope and the electron microscope has proved to be a difficult task, requiring enormous amounts of patience and technical skill. We describe a technique with a high rate of success, which can be used to identify a particular cell in the light microscope and then to embed and thin-section it for electron microscopy. The technique also includes a method to obtain many uninterrupted, thin serial sections for imaging by conventional or energy-filtered transmission electron microscopy, to obtain images for 3D analysis of detail at the suborganelle level.

AML1/MTG8 oncogene suppression by small interfering RNAs supports myeloid differentiation of t(8;21)-positive leukemic cells

The translocation t(8;21) yields the leukemic fusion gene AML1/MTG8 and is associated with 10%-15% of all de novo cases of acute myeloid leukemia. We demonstrate the efficient and specific suppression of AML1/MTG8 by small interfering RNAs (siRNAs) in the human leukemic cell lines Kasumi-1 and SKNO-1. siRNAs targeted against the fusion site of the AML1/MTG8 mRNA reduce the levels of AML1/MTG8 without affecting the amount of wild-type AML1. These data argue against a transitive RNA interference mechanism potentially induced by siRNAs in such leukemic cells. Depletion of AML1/MTG8 correlates with an increased susceptibility of both Kasumi-1 and SKNO-1 cells to tumor growth factor beta(1) (TGF beta(1))/vitamin D(3)-induced differentiation, leading to increased expression of CD11b, macrophage colony-stimulating factor (M-CSF) receptor, and C/EBP alpha (CAAT/enhancer binding protein). Moreover, siRNA-mediated AML1/MTG8 suppression results in changes in cell shape and, in combination with TGF beta(1)/vitamin D(3), severely reduces clonogenicity of Kasumi-1 cells. These results suggest an important role for AML1/MTG8 in preventing differentiation, thereby propagating leukemic blast cells. Therefore, siRNAs are promising tools for a functional analysis of AML1/MTG8 and may be used in a molecularly defined therapeutic approach for t(8;21)-positive leukemia.

Heterotypic interactions between transferrin receptor and transferrin receptor 2

Cellular iron uptake in most tissues occurs via endocytosis of diferric transferrin (Tf) bound to the transferrin receptor (TfR). Recently, a second transferrin receptor, transferrin receptor 2 (TfR2), has been identified and shown to play a critical role in iron metabolism. TfR2 is capable of Tf-mediated iron uptake and mutations in this gene result in a rare form of hereditary hemochromatosis unrelated to the hereditary hemochromatosis protein, HFE. Unlike TfR, TfR2 expression is not controlled by cellular iron concentrations and little information is currently available regarding the role of TfR2 in cellular iron homeostasis. To investigate the relationship between TfR and TfR2, we performed a series of in vivo and in vitro experiments using antibodies generated to each receptor. Western blots demonstrate that TfR2 protein is expressed strongest in erythroid/myeloid cell lines. Metabolic labeling studies indicate that TfR2 protein levels are approximately 20-fold lower than TfR in these cells. TfR and TfR2 have similar cellular localizations in K562 cells and coimmunoprecipitate to only a very limited extent. Western analysis of the receptors under nonreducing conditions reveals that they can form heterodimers.

Trisomy 15 as the sole abnormality in myelodysplastic syndromes: case report and review of the literature

Trisomy 15 as the sole autosomal anomaly is uncommon in hematological malignancies but could be preferentially associated with myelodysplasia. We report a 61-year-old man who developed pancytopenia following two courses of chemotherapy for chronic lymphoid leukemia. Cytogenetic studies at diagnosis of pancytopenia with R banding showed a 47,XY, + 15[3]/45,X[3]/46,XY[14] karyotype. A review of the 53 cases of myelodysplastic syndromes (MDS) and myeloid related disorders associated with trisomy 15 reported in the literature showed that 18 of the 31 men also lost the Y chromosome in the trisomic 15 cell line. Their mean age was significantly higher than that of males who had not lost the Y chromosome (p < 0.05). The main feature of the patient reported here is the presence of two abnormal cell lines, one having lost the Y chromosome, the other having gained a chromosome 15. Therefore, the two events occurred independently, the loss of the Y chromosome being possibly due to aging and the trisomy 15 to the hematologic disorder.

Genomic abnormalities acquired in the blastic transformation of splenic marginal zone B-cell lymphoma

Among 20 cases of typical splenic marginal zone lymphoma (SMZL), two cases had blastic transformation. The genetic mechanisms underlying the morphologic transformation were investigated by comparing genetic changes in initial and blastic phases. A complex karyotype including trisomy of 3q and genomic gain of 17q22-q24 was seen in both cases at diagnosis. However, the extra copy of 3q was lost during the transformation process in both tumors. Additionally, the Karpas 1718 cell line, which was derived from a patient with transformed SMZL and carried a trisomy of 3q, also evidenced the spontaneous loss of the extra 3q during the culturing process. Other acquired abnormalities observed exclusively in the transformation phase included amplification and/or translocation of bands 7p22-q22 and 19p13. These findings suggest that the loss of + 3q and the acquisition of other genomic imbalances may represent unique markers for the transformation process of SMZL. We hypothesize that the trisomy of 3q may correlate with the indolent nature of SMZL, and that the loss of this acquired abnormality leads to or accompanies the development of blastic tumors.

Nuclear localization of cyclin B1 regulates DNA damage-induced apoptosis

Some cells undergo apoptosis in response to DNA damage, whereas others do not. To understand the biochemical pathways controlling this differential response, we have studied the intracellular localization of cyclin B1 in cell types sensitive or resistant to apoptosis induced by DNA damage. We found that cyclin B1 protein accumulates in the nucleus of cells that are sensitive to gamma radiation-induced apoptosis (thymocytes, lymphoid cell lines), but remains cytoplasmic in apoptosis-resistant cells (primary and transformed fibroblasts). Treatment of both cell types with leptomycin B, an inhibitor of CRM1-dependent cyclin B1 nuclear export, induces apoptosis. Furthermore, ectopic expression of cyclin B1-5xE, a protein that preferentially localizes to the nucleus, is sufficient to trigger apoptosis. Conversely, expression of cyclin B1-5xA, a predominantly cytoplasmic protein, fails to induce apoptosis. This suggests that nuclear accumulation is necessary for cyclin B1-dependent apoptosis. Our observations are consistent with the idea that localization of cyclin B1 is among the factors determining the cellular decision to undergo apoptosis in response to DNA damage.

Identification of 6-methylsulfinylhexyl isothiocyanate as an apoptosis-inducing component in wasabi

The ethanol extract from Japanese horseradish wasabi was found to inhibit cell proliferation in human monoblastic leukemia U937 cells by inducing apoptotic cell death. Separation by methods including silica gel chromatography and preparative HPLC gave an active compound, which was identified as 6-methylsulfinylhexyl isothiocyanate (6-HITC). Several lines of evidence indicated that 6-HITC induced apoptosis in U937 cells and human stomach cancer MKN45 cells. Thus, 6-HITC is potentially useful as a natural anti-cancer agent.

[Effects of aminophylline on proliferation and apoptosis in Raji lympho-blastoid cell line]

The aim of this study was to investigate whether and how phosphodiesterase (PDE) inhibitors modulate the proliferation, cell cycle and apoptosis in lymphoma cells. The effects of aminophylline (AM), a non-specific PDE inhibitor, on Raji cells were explored in vitro. MTT assay, light and transmission electron microscopy and annexin V staining were used to observe cell proliferation, morphologic changes and apoptosis rate in AM-treated cells, and FCM and RT-PCR techniques were adopted to detect the effect on cell cycle, the expression of cyclin B1 and Bcl-2 and mitochondrial transmembrane potential in AM-treated cells. The results showed that AM inhibited the growth of Raji cells in a concentration-dependent manner. Morphologic observations showed apoptosis changes in AM-treated cells, including cytoplamic shrinkage, cytoplasmic bubbling, karyopyknosis and nuclear fragmentation. FCM and RT-PCR detection showed that AM intervention increased the fraction of annexin V(+) cells, reduced the value of mitochondrial transmembrane potential, induced S phase arrest, and down-regulated the expression of Bcl-2 at both mRNA and protein level and cyclin B1 protein in a concentration-dependent manner. It is concluded that PDE inhibitor aminophylline may induce Raji cell growth inhibition, S phase arrest, apoptosis via down-regulation of Bcl-2 and reduction of mitochondrial transmembrane potential.

Chromosomal alterations in osteosarcoma cell lines revealed by comparative genomic hybridization and multicolor karyotyping

We characterized the chromosomal alterations in eight osteosarcoma cell lines (OST, HOS, U-2 OS, ZK-58, MG-63, SJSA-1, Saos-2, and MNNG) by comparative genomic hybridization (CGH); gains and losses of DNA sequences were defined as chromosomal regions with a fluorescence ratio, wherein all of the 95% confidence interval was above 1.25 and below 0.75, respectively. In four of 8 cell lines, multicolor karyotyping (MK) was added. CGH revealed the average number of aberrations per cell line was 20.8 (range: 10-31); the average numbers of gains and losses were 11.1 and 9.6, respectively. The frequent gains were identified on 1p21 approximately q24, 1q25-q31, 7p21, 7q31, 8q23 approximately q24, and 14q21; frequent losses were at 18q21 approximately q22, 18q12, 19p, and 3p12 approximately p14. High-level gains were observed on 8q23 approximately q24, 5p, and 1p21 approximately p22. MK revealed the most common translocations in the four cell lines were t(8;9), t(1;3), t(3;5), t(1;13), t(2;6), t(3; 17), t(1;15), t(10;20), and t(6;20). Chromosomes 1, 3, 8, 9, and 20 were most frequently involved in translocation events. The concordance rate of aberrations in CGH and translocations in MK was 76%. MK was useful to identify the chromosomal alterations and as a supplement to the CGH results in three of four chromosomes.

Camptothecin analogues and vinblastine in the treatment of renal cell carcinoma: an in vivo study using a human orthotopic renal cancer xenograft

To perform a series of in vivo cytotoxicity studies using a variety of doses of the comptothecin analogues 9-Aminocamptothecin (9-AC) and Irinotecan (CPT-11) with a human RCC xenograft tumor line (DU11983m). Using the subrenal capsule assay (80 nude mice) (NM-SRCA), 9-AC was evaluated at both low and high dosage levels (0.75 mg/kg and 1.25 mg/kg oral x10 doses over 12 days). Following an initial assessment of acute tumor inhibition, the study was extended to a survival assay with some cohorts receiving retreatment boluses on a once or twice weekly basis. CPT-11 was assessed at a dose of 100 mg/kg x3 over 9 days with weekly retreatment and two cohorts received 9-AC combined with Vinblastine (2.7 mg/kg) and Vinblastine alone, respectively. Tumor inhibition: tumor growth inhibition was significant (over 80%) with all cohorts receiving any camptothecin analogue and was virtually complete (>99% tumor inhibition) at the high dose 9-AC (1.25 mg/kg). Vinblastine alone achieved only moderate cytotoxic effect (46%) and induced the largest recorded cohort weight loss (toxicity). Survival analysis: the low and high dose 9-AC single agent cohorts were not significantly different; however, the CPT-11 cohort experienced maximal survival benefit. (P = 0.003) and the addition of Vinblastine did not enhance this survival advantage among the 9-AC cohorts. Control and single agent Vinblastine cohorts had the poorest survival with the treated group still surviving longer (P = 0.02). At 35 days after final assessment of acute tumor inhibition, all animals in both the control and Vinblastine alone cohorts were dead. None of the animals in any of the other cohorts (all of which had experienced a greater than 80% tumor inhibition) had died. No deaths occurred due to surgery or treatment toxicity and all deaths were deemed tumor related. CPT-11 and 9-AC produced a marked survival advantage in an orthotopic model of human advanced renal carcinoma and are identified as agents for further clinical assessment.

[Investigation of apoptosis mechanism of arsenic trioxide on oral squamous cell carcinoma]

OBJECTIVE

To probe the possible mechanism of growth-inhibitory and apoptosis of oral squamous cell carcinoma by arsenic trioxide.

METHODS

The induction of apoptosis in two tongue squamous carcinoma cells treated by arsenic trioxide was investigated. The morphology changes of the cells was observed under electron microscope. The mitochondrial transmembrane potential was detected using rhodamine 123 and flow cytometry. The cell cycle was detected by flow cytometry, and p16, p53, BCL-2, Caspase-3, and PARP changes were examined by western blot.

RESULTS

1. The antiproliferative effect on the oral squamous carcinoma cells by arsenic trioxide was carried out through two ways: induction of apoptosis and toxicity damage. 2. Activation of the caspase-3 and PARP, while no changes of p16, p53, BCL-2 occurred. 3. Mitochondrial transmembrane potential collapse and G(2)-M stagnation were correlated with apoptosis of oral squamous cell carcinoma.

CONCLUSIONS

1. Tubulins and mitochondria may be the chief action position of arsenic trioxide, which is the start-up factors of mechanism. 2. Activation of the caspase-3 proteolytic pathway may be one of the pivotal ways of apoptosis procedure induced by arsenic trioxide.

Fibroblast growth factor-inducible 14 mediates multiple pathways of TWEAK-induced cell death

TWEAK, a TNF family member, is produced by IFN-gamma-stimulated monocytes and induces multiple pathways of cell death, including caspase-dependent apoptosis, cathepsin B-dependent necrosis, and endogenous TNF-alpha-mediated cell death, in a cell type-specific manner. However, the TWEAK receptor(s) that mediates these multiple death pathways remains to be identified. Recently, fibroblast growth factor-inducible 14 (Fn14) has been identified to be a TWEAK receptor, which was responsible for TWEAK-induced proliferation of endothelial cells and angiogenesis. Because Fn14 lacks the cytoplasmic death domain, it remains unclear whether Fn14 can also mediate the TWEAK-induced cell death. In this study, we demonstrated that TWEAK could induce apoptotic cell death in Fn14 transfectants. A pan-caspase inhibitor, benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone, rather sensitized the Fn14 transfectants to TWEAK-induced cell death by necrosis via reactive oxygen intermediates and cathepsin B-dependent pathway. By using newly generated agonistic anti-Fn14 mAbs, we also observed that Fn14 is constitutively expressed on the cell surface of all TWEAK-sensitive tumor cell lines, and can transmit the multiple death signals. Moreover, an anti-Fn14 mAb that blocks TWEAK-Fn14 interaction could totally abrogate TWEAK binding and TWEAK-induced cell death in all TWEAK-sensitive tumor cell lines. These results revealed that the multiple pathways of TWEAK-induced cell death are solely mediated by Fn14.

XIB4035, a novel nonpeptidyl small molecule agonist for GFRalpha-1

We investigated the agonistic activities of N(4)-(7-chloro-2-[(E)-2-(2-chloro-phenyl)-vinyl]-quinolin-4-yl)-N(1),N(1)-diethyl-pentane-1,4-diamine (XIB4035), at the glial cell line-derived neurotrophic factor (GDNF) family receptoralpha-1(GFRalpha-1) in Neuro-2A cells, a mouse neuroblastoma cell line which is a suitable model for investigating functions mediated through GFRalpha-1. XIB4035 concentration-dependently inhibited [(125)I]GDNF binding in Neuro-2A cells with an IC(50) of 10.4 microM. GDNF induced autophosphorylation of Ret protein, and promoted neurite outgrowth in Neuro-2A cells. XIB4035, like GDNF, induced Ret autophosphorylation in the Neuro-2A cells. Moreover, XIB4035 promoted neurite outgrowth in a concentration-dependent manner. These results show that XIB4035 may act as an agonist at GFRalpha-1 receptor complex, and mimic neurotrophic effects of GDNF in Neuro-2A cells. This is an interesting finding showing that a nonpeptidyl small molecule is capable of inducing activation of a receptor that normally bind a relatively large protein ligand such as GDNF.