bluuebunny/crossref_metadata_2025 huggingface dataset:
Lymphocytes activated by the epstein‐barr virus to produce immunoglobulin do not express CD23 or become immortalized
Authors: Azim Tasnim , Crawford Dorothy H.
Published: February 2007

Epstein‐Barr virus causes polyclonal activation and immortalization of a small percentage of peripheral blood B lymphocytes after in vitro infection. However, the susceptible B lymphocytes have not been identified. We have used the B lymphocyte activation antigen, CD23, as a marker for separating immortalized and non‐immortalized Epstein‐Barr virus‐infected B lymphocytes and have identified the polyclonally‐activated cells, using double staining for cytoplasmic immunoglobulin and viral antigens. The vast majority of cells expressing cytoplasmic immunoglobulin are negative for CD23 and for Epstein‐Barr virus nuclear antigen, and are non‐immortalized. Conversely, the CD23‐positive, immortalized population are positive for Epstein‐Barr virus nuclear antigen and negative for cytoplasmic immunoglobulin. These results define a diversity in the response of B lymphocytes to Epstein‐Barr virus infection and suggest separate pathways for terminal differentiation and immortalization. This diversity may be important in determining the outcome of Epstein‐Barr virus infection in humans.
Quantitative assays of epidermal growth factor receptor in human breast cancer: Cut‐off points of clinical relevance
Authors: Nicholson S. , Sainsbury J. R. C. , Needham G. K. , Chambers P. , Farndon J. R. , Harris A. L.
Published: February 2007

Epidermal growth factor receptor (EGFr) assays were performed by 3 different methods on 246 human primary breast carcinomas. Scatchard analyses of multipoint binding data on 19 of the first 209 tumours, performed by a displacement method, demonstrated that the majority of tumours exhibited 2 classes of binding site, the high‐affinity site with an affinity constant (KD) of mean 2 nmol/l (SD 1.3, range 0.44‐7 nmol/l), and a low‐affinity site, KD mean 9.5 nmol/l (range 6–15.5 nmol/l). Scatchard analysis of multipoint assays using increasing concentrations of 125I‐labelled EGF showed that saturation of the high‐affinity site occurred in the majority of tumours at a concentration of labelled EGF of 1 nM. Comparison of the KD values of the high‐affinity site obtained from displacement assays with those obtained by increasing labelled EGF showed that the KD was significantly higher (p = 0.0002) when measured by the latter method. There was no difference in binding capacity of the high‐affinity or low‐affinity sites by the 2 methods. A 2‐point assay with 1 nM labelled EGF (specific activity approx. 80–130 μCi/μg) correlated with quantitative values for the high‐affinity site from Scatchard analysis (p < 0.02). There was a strong inverse relationship between EGFr > 10 fmol/mg membrane protein (2‐point assay) and ER (dextran‐coated charcoal method), Chi‐squared 2 × 2 contingency table test = 34.027, p < 0.0001. Follow‐up data from 135 patients revealed a strong inverse relationship between EGFr > 10 fmol/mg membrane protein and oestrogen receptor (ER) status and a positive correlation with early recurrence and death. Our data describe a reproducible assay for EGFr and show that a cut‐off point at 10 fmol/mg allows clinically useful application.
TPA enhancement of the recovery of methotrexate and N‐phosphonacetyl L‐aspartate resistant mouse 3T6 cell clones is associated with transient alterations of cell cycle progression
Authors: Szallasi Arpad , Fox Margaret , Kinsella Anne R.
Published: February 2007

The effects of methotrexate (MTX) and N‐phosphonacetyl L‐aspartate (PALA) with and without 12‐O‐tetradecanoyl‐phorbol‐13‐acetate (TPA) have been tested on the cell‐cycle traverse of mouse 3T6 and Chinese hamster V79 cell lines. MTX, whether administered with or without TPA, had very little effect on the cell cycle of the V79 Chinese hamster cell line. However, low MTX concentrations produced a significant G1 accumulation in the mouse 3T6 cell line after 24 hr, and this was accentuated by TPA treatment. These findings parallel previous observations that TPA enhances the recovery of MTX‐ and PALA‐resistant mouse 3T6 cell clones but has little or no effect on drug‐resistant colony recovery in the V79 Chinese hamster cell line. The possibility that the increase in accumulation of cells in G1 might permit the rescue of an increased proportion of cells due to the release of purines and pyrimidines from dying cells is discussed. Such rescue should occur irrespective of whether or not the cell line has the ability to amplify its target genes.
Expression of differentiation antigens within human mammary tumours is related to response to endocrine therapy and survival
Authors: Baildam A. D. , Howell A. , Barnes Diana M. , Redford Judy , Healy Karen , Swindell R. , Sellwood R. A.
Published: February 2007

Human mammary tumours which are histologically well differentiated are more likely to synthesize receptors for estrogen (ER) and progesterone (PR) and to respond to systemic endocrine therapy. The aim of this study was to explore the relationship between differentiation, receptors and endocrine responsiveness in more detail by relating the expression of putative differentiation antigens within tumours to ER, PR and response to treatment. Sections of the primary tumours of 160 patients with advanced evaluable breast cancer were immunostained with 2 monoclonal antibodies (MAbs) (HMFGI and HMFG2) raised against putative differentiation antigens found on the membranes which surround the milk fat globule. Tumours were highly heterogeneous with respect to antigen expression. However, the number of cells which expressed the antigens was highly correlated with ER and PR concentrations and with response to endocrine therapy. In tumours where ⩾ 20% of cells expressed the antigen recognized by HMFGI, 73% responded to endocrine therapy; this was similar to the response predicted by ER (67%) and PR (73%). Expression of HMFGI was correlated with survival from the start of endocrine therapy (p < 0.0001) to the same degree as ER and PR. Patients with tumours which expressed ER, PR and HMFGI had the highest response rate (87%) and survival (median 49 months); the response in tumours which expressed none of these phenotypes was 13% and the median survival of these patients was 9 months. These results suggest that cells which express differentiation antigens also express ER and PR. Differentiated cells within mammary tumours may therefore be the target cells for systemic hormone, and also the source of factors which control tumour growth.
Recent trends in cancer incidence among Singapore Chinese
Authors: Lee H. P. , Duffy S. W. , Day N. E. , Shanmugaratnam K.
Published: February 2007

Since the inception of cancer registration in Singapore in 1968, the incidence rates of malignancies have been monitored among the 3 major ethnic groups–Chinese (77% of population), Malays (15%) and Indians (6%). Substantial changes in incidence at various sites were observed in the period 1968–1982, which seem to represent a shift from the pattern of cancer incidence in China towards that prevailing in the West. We now report on the Singapore Chinese experience, in which the following changes were notable: decreases in rates of cancers of the stomach and oesophagus and increases in rates of cancers of the lung, colon, rectum, skin (excluding melanoma), breast and ovary. For several sites, the secular changes differed among age groups; among women under 50 years of age breast cancer increased particularly sharply and lung cancer decreased. Environmental and personal factors, potentially responsible for the change, are discussed.
DNA blotting analysis of human retroviruses in cerebrospinal fluid of spastic paraparesis patients: The viruses are identical to human T‐cell leukemia virus type‐1 (HTLV‐1)
Authors: Imamura Jun , Tsujimoto Atsumi , Ohta Yoshihiro , Hirose Shozo , Shimotohno Kunitada , Miwa Masanao , Miyoshi Isao
Published: February 2007

The structure of the integrated provirus in cell lines established from the cerebrospinal fluid (CSF) of patients with human T‐cell leukemia virus type‐1 (HTLV‐1)‐associated myelopathy (HAM) was analyzed. The digestion patterns with 3 restriction endonucleases, Sac I, Eco RI and Pst I, of the proviruses integrated in T‐lymphoid cell lines derived from the CSF of 4 HAM patients were similar to those of HTLV‐1 from adult T‐cell leukemia (ATL) patients. Integrated proviruses in one of these cell lines derived from the CSF were further analyzed in detail with 2 more restriction enzymes, BamHI and Sma I. The results indicate that the retrovirus found in lymphocytes of the CSF from patients with HAM are very similar, if not identical, to HTLV‐I found in the leukemic lymphocytes of ATL patients.
Reproductive factors and risk of ovarian cancer: A prospective study
Authors: Kvåle Gunnar , Heuch Ivar , Nilssen Steinar , Beral Valerie
Published: February 2007

Associations between reproductive factors and risk of ovarian cancer were examined in a prospective study of 60,565 women in Norway. A total of 445 women were diagnosed as having ovarian cancer during follow‐up, from 1961 through 1980. The highest risk was observed among nulliparous women, and the risk decreased significantly with increasing parity. The estimated odds ratio for women with 5 or more births compared with one birth was 0.46, after adjustment for age, urban/rural place of residence and occupational class. Neither age at first or last birth, nor age at menarche or menopause, nor marital status, showed significant associations with ovarian cancer risk after adjustment for parity. The apparent protective effect of high parity was observed for epithelial as well as non‐epithelial cancers, and for the separate histological types of epithelial cancer except mucinous cystadenocarcinomas.
Cytomatrix reorganization in dimethyl sulfoxide‐induced “Qi” substate murine hepatic tumor cells
Authors: Ryan Michael P. , Higgins Paul J.
Published: February 2007

Cultured murine hepatic tumor (HT) cells respond to the polar solvent dimethylsulfoxide (DMSO) with specific alterations in morphology, proliferative kinetics, and biochemical properties. These include entrance into a quiescent “Qi” substate (characterized by accumulation of cells in GI phase and lowered cellular RNA content), enhanced production of liver‐specific proteins, and decreased expression of growth traits characteristic of the transformed phenotype. Entrance of HT cells into Qi was associated with increased monolayer compaction and a shift from an elaborate surface fibronectin (FN) network to a sparse and restricted distribution of FN fibers. This marked decrease in the extent and complexity of the cellular FN network, as a consequence of DMSO exposure, was reflected in a 90% decline in the amount of FN secreted into the culture medium. These data complement previous studies indicating that the accumulation and composition of liver cell matrix substances reflect altered patterns of hepatocyte‐specific gene expression. In the HT cell system, DMSO appears to act in a bifunctional manner, increasing the production of certain tissue‐specific proteins (e. g., albumin and alphafetoprotein) while decreasing the secretion and deposition of other cellular components (FN). DMSO may directly regulate expression of these proteins in HT cells or alter the pattern of cellular response to specific autocrine growth factors.
Photosensitization of differentiating friend erythroleukemic cells by hematoporphyrin derivative and the cholesterol effect
Authors: Lejbkowicz Flavio , Malik Zvi , Salzberg Samuel
Published: February 2007

The Friend erythroleukemia cell line was used to study the binding and biological properties of the photosensitizer hematoporphyrin derivative (HPD) on a differentiating system. In addition, the effect of cholesterol hemisuccinate (CHS) enrichment of cell membranes on HPD activity was tested on the same cell system. Differentiation of Friend erythroleukemia cells (FLC) was induced with dimethyl sulfoxide (DMSO) and resulted in a decreased cell volume and an increased rate of hemoglobin synthesis as a function of the duration of DMSO treatment. Differentiated cells seem to bind less porphyrin than their undifferentiated counterparts. Thus, cells treated for 6 days with DMSO bound 30–40% less dye than an identical number of untreated FLC. In contrast, a similar inhibition of both DNA and protein synthesis by photoactivated HPD was evident in either DMSO‐treated or untreated FLC. Enrichment of cell membranes with CHS led to the same degree of protection from the damaging activity of the photoactivated dye in both differentiated and undifferentiated FLC. The decreased binding of HPD to DMSO‐treated FLC is most likely a result of a reduction in cell volume of differentiated cells and is not related to an intrinsic property of the differentiation process.
Expression of Epstein‐Barr virus‐encoded proteins in nasopharyngeal carcinoma
Authors: Fåhraeus Robin , Fu Hu Li , Ernberg Ingemar , Finke Jurgen , Rowe Martin , Klein George , Falk Kerstin , Nilsson Ethel , Yadav Manmohan , Busson Pierre , Tursz Thomas , Kallin Bengt
Published: February 2007

Expression of the Epstein‐Barr virus (EBV) encoded nuclear antigens (EBNA 1 to 6) and membrane‐associated protein (LMP) was investigated by immunoblotting in 83 nasopharyngeal carcinoma (NPC) biopsies and 25 other tumor and normal tissue specimens from the head and neck region. Fifty‐eight of the 83 NPC biopsies were large enough to yield parallel data on virus DNA and viral expression. All 16 cases of clinically diagnosed and histologically confirmed NPCs from North Africa contained EBV DNA and expressed EBNA‐1. Of 31 clinically diagnosed NPCs from China, 29 contained EBV DNA and 25 of these expressed EBNA‐1. One control tissue biopsy from the oropharynx of NPC patients contained EBV DNA, but none expressed EBNA‐1. The latent membrane protein (LMP) was detected in 22/31 of the Chinese and in 10/16 of the North African NPC biopsies. None of the NPC biopsies or control tissues expressed detectable amounts of EBNA 2 or any of the other 4 nuclear antigens which are invariably expressed in EBV‐transformed B cells. A smaller number of tumors from Malaysia and East Africa exhibited a similar pattern of expression. EBV was rescued from a nude‐mouse‐passaged North African NPC tumor by co‐cultivation of the tumor cells with umbilical cord blood lymphocytes. The tumor expressed EBNA 1 and LMP, but not EBNA 2 or the other 4 EBNAs. The resulting LCLs expressed all 6 nuclear antigens, EBNA 1 to 6 and LMP. Our data suggest that expression of the EBV genome is regulated in a tissue‐specific fashion.
Effect of recombinant human tumor necrosis factor on tumor and spleen in mice
Authors: Knippel E. , Rychly J. , Schulze H. A. , Ringel B. , Krygier‐Stojalowska A.
Published: February 2007

The ability of recombinant human tumor necrosis factor (rH‐TNF‐α) to induce regression of sarcoma 180 in vivo was evaluated. The tumor was cured by TNF in the course of 4 weeks. TNF inhibited proliferation of sarcoma 180 cells in vitro, which suggests a direct effect of TNF on tumor cells in vivo. In parallel to the TNF effect on tumor growth, some cell parameters in spleen were investigated. Activation of splenic macrophages was enhanced in vitro. This result suggests that macrophages may participate in the host defense against the tumor. In the first phase of therapy, TNF did not affect the proliferation of splenocytes but increased the transition of G0 into G1 cells. Furthermore, TNF normalized the tumor‐induced increase of null cells in tumor‐bearing mice. All parameters investigated in spleen reached normal values at the time of tumor regression. Our results suggest that various mechanisms may be involved in TNF‐induced regression of sarcoma 180.
Effects of bilateral and unilateral vagotomy on gastric carcinogenesis induced by N‐methyl‐N′‐nitro‐N‐nitrosoguanidine in wistar rats
Authors: Tatsuta Masaharu , Iishi Hiroyasu , Yamamura Hisako , Baba Miyako , Taniguchi Haruo
Published: February 2007

After administration of N‐methyl‐N′‐nitro‐N‐nitrosoguanidine for 15 weeks, the effects of bilateral, anterior and posterior vagotomy on the incidence, number and location of gastric adenocarcinomas, gastric acid secretion and cell proliferation of the gastric mucosa were investigated in inbred Wistar rats. Bilateral or anterior vagotomy, but not posterior vagotomy, significantly increased the incidence and number of adenocarcinomas at experimental week 52. In sham‐operated control rats and rats subjected to bilateral vagotomy, there was no significant difference between the incidence or number of gastric tumors in the anterior and posterior walls. After anterior and posterior vagal denervation, however, there were significantly more gastric cancers on the denervated side than on the other. Bilateral and unilateral vagotomy resulted in significantly reduced gastric acid secretion by experimental weeks 25 and 52. Bilateral vagotomy significantly increased the labelling indices of both the fundic and antral mucosa at both times, but did not cause any significant difference between those of the anterior and posterior wall. Anterior or posterior vagotomy resulted in a significant increase in the labelling indices of both the fundic and antral mucosa on the denervated side. These findings indicate that the vagal nerve exerts a trophic action on the gastric mucosa, and that the promoting effect of vagotomy on gastric carcinogenesis may be related to its effect in increasing proliferation of cells in the antral mucosa.
Interferon‐gamma‐induced alterations of monocyte susceptibility to lysis by autologous lymphokine‐activated killer (LAK) cells
Authors: Djeu Julie Y. , Blanchard D. Kay
Published: February 2007

Interleukin‐2 (IL‐2)‐activated killer (LAK) cells specifically lyse human monocytes, which may account for some of the toxicity seen during LAK/IL‐2 immunotherapy of cancer patients. In an effort to protect autologous monocytes, we treated monolayer cultures of monocytes with various doses of recombinant human interferon‐gamma (IFN‐gamma) and assessed their sensitivity to LAK‐mediated lysis. IFN‐gamma lessens the sensitivity of monocytes to lysis in a dose‐dependent manner. Treatment of FMEX, an NK‐resistant melanoma tumor cell line, with IFN‐gamma did not affect its susceptibility to LAK lysis. Kinetic studies demonstrated that as little as 2 hr incubation with IFN‐gamma was sufficient for protection to occur, and that monocytes which were treated with IFN‐gamma for 2 hr, washed, and then cultured in medium alone retained their resistance to lysis for at least 4 days. Cold target inhibition studies showed that IFN‐treated and untreated monocytes could effectively compete with each other for binding sites on LAK cells. Finally, binding studies demonstrated that there was no significant difference between the number of conjugates formed using either IFN‐treated or untreated monocytes. This indicates that resistance to lysis induced by IFN treatment affects a post‐binding event and not an initial recognition signal.
Anti‐tumor surveillance of non‐contact‐inhibited transformed cell lines
Authors: Vanderslice W. Eric , Collins John Leslie
Published: February 2007

In order to determine if the correlated expression of transformation and tumorigenicity is affected by the agents used to induce transformants or by the immune status of the host used to test the tumorigenicity of transformants, we derived a series of cloned cell lines from foci of transformed cells induced by treatment of the contact‐inhibited mouse cell line B/C‐N7. ICI with the DNA demethylating agent 5‐azacytidine (5‐AZC) or the DNA demethylating and mutating agent benzo(a)pyrene dihydrodiol epoxide (BPDE). The transformed cell lines were injected into syngeneic nude and normal mice to determine their tumorigenicity. The results of this analysis showed that 93% of the transformants induced by 5‐AZC treatment grew as tumors when injected into nude mice. Of those lines capable of growing as tumors in nude mice, 86% were also tumorigenic when injected into normal mice. In contrast, only 64% of BPDE‐induced transformants grew as tumors in nude mice, and of those, only 44% were also tumorigenic in normal mice. The existence of non‐contact‐inhibited transformants that are tumorigenic only in nude mice indicates that host anti‐tumor immune surveillance mechanisms are operative in normal mice. Further, the difference in both the percentage of transformed cell lines that are tumorigenic and the percentage of tumorigenic transformants that are susceptible to immune surveillance when transformants are induced by BPDE as compared to 5‐AZC indicates that the transforming agent can affect both the correlation between the expression of transformation and tumorigenicity, and the interaction between the immune system and tumorigenic transformants.
Tumor‐selective cytotoxic effects of murine tumor necrosis factor (TNF) and interferon‐gamma (EN‐gamma) in organ culture of B16 melanoma cells and heart tissue
Authors: Mareel Marc , Dragonetti Christian , Tavernier Jan , Fiers Walter
Published: February 2007

Organotypically cultured, confronting pairs of B16B16 cell clusters and fragments of embryonic chick or mouse heart, as used for the study of invasion in vitro, were treated with murine TNF plus IFN‐gamma for 4 and 7 days. This treatment selectively killed the B16B16 cells and left the heart tlssue intact as assayed by histology and by plating confronting pairs and spent medium on tissue culture substrate. Using this organ culture assay, which more closely mimics the situation in vivo, we confirmed the tumor‐selective cytotoxic effects of combined treatment with TNF and IFN‐gamma as observed in separate cultures of malignant and non‐malignant cells on “artificial” substrate.
Carcinoid tumour cells in long‐term culture: Release of serotonin but not of tachykinins on stimulation with adrenoceptor agonists
Authors: Ahlman H. , Åhlund L. , Nilsson O. , Skolnik G. , Theodorsson E. , Dahlström A.
Published: February 2007

Tumour cells from a lymph‐node metastasis of a midgut carcinoid tumour, Immunoreactive for serotonin and substance P, were isolated and kept in culture for 2 months. The formation of large clusters or islets of tumour cells was paralleled by an increase in immunoreactive tachykinins {neuropeptide K and substance P} in the culture medium. The concentration of tachykinins declined subsequently despite good viability of the cells. Spontaneous release of serotonin into the culture medium was much greater than that of tachykinins, and remained stable throughout the study. These findings indicate different turnover rates and/or different storage sites for the peptides and the amine. In stimulation experiments, a dose‐dependent release of serotonin, but not of tachykinins, was induced by a β‐adrenoceptor aganist (isoprenaline), while stimulation of α‐adrenoceptors (noradrenaline) was not effective In releasing any of the substances. Pretreatment of the cultures with a β‐adrenoceptor antagonist {propranolol} or stimulations after calcium deprivation did not influence the isoprenaline‐induced release of serotonin. These findings may indicate a modification of genuine β‐adrenoceptors during culture.
abl oncogene expression in non‐Hodgkin lymphomas: Correlation to histological differentiation and clinical status
Authors: Greil R. , Gattringer C. , Fasching B. , Cleveland J. , Thaler J. , Radaskiewicz T. , Gastl G. , Huber C. , Rapp U. , Huber H.
Published: February 2007

Eight reactive lymphatic tissues, 166 cases of non‐Hodgkin lymphomas (NHL) and 11 cases of multiple myeloma were investigated for expression of the c‐abl protein using the polyclonal anti‐abl antibody 4411 and an indirect peroxidase technique. In selected cases the results were compared to those obtained with a second polyclonal and 2 monoclonal anti‐abl antibodies. In 7 cases, Northern blot analysis of abl‐mRNA was performed in parallel. In reactive lymphatic tissues, cells positive for the 4411 antibody were confined to the B‐cell areas, i. e., to the mantle zone and parts of the germinal center. In NHL, a positive staining of the cell membrane was predominantly detectable in lymphomas putatively originating in the germinal center or mantle zone (in particular in centrocytic NHL), independent of their proliferative activity. Clinically, 7 out of 8 abl‐positive cases of chronic lymphocytic leukemia (CLL) had a more aggressive course of disease, whereas “progressive disease” occurred in only 7 out of 19 c‐abl antigen‐negative cases. When the clinical status of 78 patients with NHL and II patients with multiple myeloma was related to c‐abl expression, c‐abl‐positivity was mostly confined to patients in advanced tumor stages [p<0.001 (NHL)].
A TaqI RFLP of the human TGFα gene is significantly associated with cutaneous malignant melanoma
Authors: Hayward Nicholas , Nancarrow Derek , Ellem Kay , Parsons Peter , Kidson Chev
Published: February 2007

A Taql restriction fragment length polymorphism (RFLP) of the human transforming growth factor alpha (hTGFα) locus was analyzed in DNA from 63 normal individuals, 34 malignant melanoma (MM) cell lines, and 18 melanoma biopsy specimens. The frequency of a 2.7‐kb allele (0.18) in MM cell lines was significantly higher P < 0.01) than in lymphoblastoid cell lines (LCLs) derived from unaffected controls (0.05). The frequency (0.14) in MM biopsies was similar to that in MM cell lines although, owing to the small numbers investigated, it was not significantly higher than in controls. In the case of 5 MM patients who were constitutionally heterozygous for alleles at the TGFα locus, no apparent losses of heterozygosity were observed in the corresponding tumour DNA. Thus, the constitutional presence of the 2.7‐kb allele may be a risk factor for melanoma.
Establishment and characterization of three transplantable EBV‐containing nasopharyngeal carcinomas
Authors: Busson P. , Ganem G. , Flores P. , Mugneret F. , Clausse B. , Caillou B. , Braham K. , Wakasugi H. , Lipinski M. , Tursz T.
Published: February 2007

Three transplantable nasopharyngeal carcinoma (NPC) tumors, designated C15, C17 and C18, have been obtained and characterized. C15, derived from a primary NPC tumor, has been propagated in nude mice for 30 passages. C17 and C18, derived from metastatic NPC tissue, have been passaged 10 times. Desmosomes, present in every case, provided confirmation of the epithelial origin of all 3 tumors. The Epstein‐Barr virus (EBV) genome is contained in C15, C18 and C17 tumor cells with 30, 12 and 3 copies, respectively. The Epstein‐ Barr virus nuclear antigen (EBNA) was stained by the classical anti‐complement immunofluorescence (ACIF) technique. Fluorescence intensity was strong in C15, moderate in C18, and hardly detectable in C17 cells. No expression of the EA and VCA antigens was detected. Flow cytometry analysis performed on monocellular suspensions showed the absence of detectable CR2 molecules (the EBV receptor on B lymphocytes) in all 3 tumors, and the constitutive expression of HLA class‐II antigens in C15 and C17 cells. IL‐1 activity was demonstrated in the supernatant of C15 and C17 cells cultivated in vitro for 3 days. These data confirm that the constitutive synthesis of MHC class‐II molecules and the release of IL‐1‐like activities are frequent features of NPC cells. These characteristics could be of importance in relation with the T‐cell infiltrate found in NPC primary tumors.
Development and characterization of a syngeneic monoclonal antibody to a rat mammary tumor metastasis‐associated mucin like cell‐surface antigen (gp580)
Authors: North Susan M. , Steck Peter A. , Spohn William H. , Nicolson Garth L.
Published: February 2007

A rat hybridoma producing IgM monoclonal antibody (MAb) GP21:56 was generated with specificity for a high‐molecularweight, mucin‐like glycoprotein (gp580) present on highly metastatic 13762NF rat mammary adenocarcinoma cells. The hybridoma was made by fusing rat Y3 Ag1.2.3 myeloma cells with spleen cells from a rat immunized i. d. with purified gp580. The gp580 appeared to be of low immunogenicity in syngeneic F344 rats because a total of 27 fusions were required to produce one hybridoma with specificity for this glycoprotein. Immunoblotting of purified gp580 after electrophoresis in 1% agarose and antibody‐binding assays using purified gp580 linked to microtiter plates confirmed that MAb GP21:56 bound specifically to gp580. Other MAbs made against breast mucins were negative for gp580 reactivity. Enzymelinked immunoabsorbent assays (ELISA) and radiolabelled antibody binding assays demonstrated that MAb GP21:56 bound to 13762NF adenocarcinoma cell lines and clones in relation to their spontaneous metastatic potentials; significantly more MAb GP21:56 bound to highly metastatic MTLn3 cells than to low metastatic MTC cells, and MAb GP21:56 showed little reactivity towards the majority of other cell lines tested, whether of rodent or of human origin. Kinetic binding studies indicated that MAb GP21:56 does not have a high affinity for gp580 but, once bound, it shows high avidity for this sialogalactoprotein. Localization studies using frozen tissue sections of 13762NF tumors indicated that MAb GP21:56 reacts with tumor cells grown in vivo in an analogous manner to in vitro cultured cells. Using immunoperoxidase techniques, less than 50% of the highly metastatic MTLn3 tumor cells were stained, whereas approximately 20% of the intermediate metastatic MTF7 and MTLn2 cells and < 10% of low metastatic MTC and MTPa cells were stained with MAb GP21:56. The cell‐to‐cell reactivity was heterogeneous and mainly associated with the tumor‐cell surface and extracellular matrix.
Differentiation of the human pancreatic adenocarcinoma cell line (Capan‐1) in culture and co‐culture with fibroblasts dome formation
Authors: Levrat J. H. , Palevody C. , Daumas M. , Ratovo G. , Hollande E.
Published: February 2007

This study was designed to investigate differentiation of human pancreatic duct carcinoma cells (Capan‐I) in vitro. Observations on live cells, and electron microscopic examination, together with enzymological and immunocytochemical methods, have demonstrated that these cells differentiate spontaneously at an early stage. The cells are seen to be joined by apical junctions. High ATPase activity can be detected in the basolateral membranes, and the cells secrete a gastric type mucin (MI) bearing acidic groups. During differentiation in culture, they form domes which are thought to be the morphological expression of trans‐epithelial transport of water and electrolytes. This particular structure is transitory, since after 6 days in culture all the cells lose their adhesivity, and form into floating cords. Co‐culture of Capan‐I cells and human, nude mice or chick embryo fibroblasts leads to a higher degree of differentiation of epithelial cells, reflected by the earlier appearance of numerous domes. In addition, the anchorage of Capan‐I cells to fibroblasts prevents retraction of the monolayer, and enables the domes to be maintained in the cultures for more than one month. These findings suggest that Capan‐I cells are able to carry out trans‐epithelial movement of water and electrolytes. It is suggested that excretion of ions (bicarbonate and/or chloride) is preserved after transformation of pancreatic duct cells. Mucins (MI) and the recently described VIP receptor sites are also thought to play a part in these exchange processes.
Proliferative and cytolytic potentials of purified human tumor‐infiltrating t lymphocytes. Impaired response to mitogen‐driven stimulation despite T‐cell receptor expression
Authors: Miescher S. , Stoeck M. , Qiao L. , Barras C. , Barrelet L. , von Fliedner V.
Published: February 2007

Using limiting dilution analysis (LDA) we have previously shown that in most instances, the frequency (F) of proliferative T lymphocyte precursors (PTL‐P) was strikingly reduced in tumor‐infiltrating lymphocytes (TIL). In this study involving 19 cases, we show that the impaired clonogenic potential of CD2+ TILs is primarily caused by an intrinsic defect rather than to suppressor T cells or to a direct effect of the tumor cells usually present in the culture system. This was demonstrated by experiments in which the F of PTL‐Ps was quantitated both in highly purified CD2+ TILs (using a cell‐sorter) and in non‐purified TIL suspensions (still containing tumor cells), which originated from the same biopsy specimen. The F of PTL‐Ps was virtually identical in either sorted or non‐sorted suspensions and the data from LDA were always consistent with the single‐hit Poisson model, indicating that no suppressor cells interfered with growth of CD2+ TIL. Stimulation of sorted CD2+ TIL in low‐density cultures by either phytohemagglutinin or anti‐CD3‐monoclonal antibody (MAb) indicated that the antigen‐dependent activation pathway was impaired, although structurally intact T‐cell receptor (TCR) complexes were apparently expressed, as assessed by immunofluorescence. The depressed proliferative response of CD2+ TIL could not be reversed in vitro when phorbol‐esters were used in combination with ionomycin, which bypass the TCR. Nevertheless, 180 clones obtained from 8 cases were analyzed for their cytolytic activity. The majority mediated specific lytic activity (against unknown antigens), as assessed by lectindependent cell cytotoxicity, whereas only 6% of them manifested lymphokine‐activated killing on appropriate targets.
Ovarian cancer incidence and mortality in denmark, 1943‐1982
Authors: Ewertz Marianne , Kjaer Susanne Krüger
Published: February 2007

Trends in ovarian cancer incidence and mortality were examined using data from the Danish Cancer Registry and national mortality statistics respectively. The study population comprised 17,956 incident cases diagnosed between 1943 and 1982 and 11,904 deaths between 1953 and 1982 due to cancer in the ovaries, Fallopian tube, and broad ligament. A significant 50% increase in incidence occurred from 1943 to 1972, whereafter a slight decrease was observed. This rise could be ascribed entirely to an increasing incidence among women born between 1863 and 1898. No change was seen in women born after 1900. Analysis of mortality confirmed the increasing ovarian cancer risk among women born during the last century, but indicated that the risk of dying from ovarian cancer decreased with time among women born after 1900. The observed trends were compatible with cohort‐specific changes in fertility in Danish women born between 1890 and 1934. The effect of age on ovarian cancer incidence, overall and by histologic type, agreed well with previous findings.
Purification and characterization of the epstein‐barr virus nuclear antigen 2 using monoclonal antipeptide antibodies
Authors: Dillner Joakim , Wendel‐Hansen Vidar , Kjellström Gunilla , Kallin Bengt , Rosén Anders
Published: February 2007

The Epstein‐Barr virus (EBV) nuclear antigen 2 (EBNA‐2) is the only one of the EBNA proteins to have been implicated as an EBV‐encoded transforming protein. More detailed studies of this protein have been hampered by the lack of EBNA‐2‐specific monoclonal antibodies (MAbs) and of purified protein. To overcome these problems, we isolated 5 hybridomas producing MAbs reactive with an 18 residue synthetic peptide corresponding to the carboxyterminus of EBNA‐2. Four of the 5 MAbs were specifically reactive with EBNA‐2 in its denatured form on immunoblots. The 5th antibody (IISE) was reactive with the native form of EBNA‐2. By using a one‐step immunoaffinity purification method with II5E cross‐linked to protein‐A‐Sepharose, we purified EBNA‐2 to homogeneity, i. e., more than 1,200‐fold, from Burkitt lymphoma cell extracts. A major 32‐kDa associated protein and a less abundant 17‐kDa protein were co‐purified with EBNA‐2. Immunoprecipitation with 115E from 35S‐methionine‐labelled cell extracts showed that the 32‐kDa protein co‐precipitated with EBNA‐2 from EBV‐positive cells, but was not detectable in immunoprecipitates of EBV‐negative cells. When the immunoprecipitates or the purified proteins were immunoblotted with EBV‐immune sera, only EBNA‐2 was reactive, indicating that the associated proteins are of cellular origin. Immunoprecipitation of cells labelled with 32P‐orthophosphate showed that EBNA‐2, but not the associated proteins, is a phosphoprotein. The expression level of EBNA‐2 varied between different EBV‐carrying cell lines, as measured by a 2‐site ELISA based on antibody II5E. In indirect immunofluorescence, the II5E MAb gave an EBNA‐2‐specific characteristic granular staining pattern. These characteristics of EBNA‐2 resemble those of other viral transforming proteins.
Melanoma antigen expression and metastatic ability of mutant B16 melanoma clones
Authors: Nozue Mutsumi , Sakiyama Hisako , Tsuchiya Kouji , Hirabayashi Yoshio , Taniguchi Masaru
Published: February 2007

The biological functions of murine melanoma‐associated antigens recognized by monoclonal antibodies (MAbs) (M562, M622 and M2590) were examined by using mutant clones which differed in their degree of expression of these antigens. Four clones of high expressors of 3 types of antigen (MEA group), 5 clones of low or non‐expressors of M562‐ and M622‐recognizing antigens (MEB group) and 4 clones of non‐expressor of GM3 recognized by M2590 (MEC group) were used. Attachment of these clones to components of extracellular matrix was different between the groups. Two clones of the MEA group showed the highest ability to adhere to laminin and type‐IV collagen, whereas the clones of the MEB and MEC groups significantly lost their ability to attach to laminin and type‐IV collagen. In experimental lung metastasis, metastasizing ability of MEA‐group cells was higher than that of MEB‐and MEC‐group cells. Our results suggest that these antigens play some functional role in metastasis mediated by increasing capacity for attachment to laminin and type‐IV collagen.
Polyamine‐directed preferential nutritional repletion of normal tissues in tumor‐bearing hosts
Authors: Nishioka Kenji , Grossie V. Bruce , Ajani Jaffer A. , Patenia Domitila , Chang Tai‐Hwa , Ota David M.
Published: February 2007

Our previous study demonstrated that total parenteral nutrition (TPN) increases erythrocyte (RBC) polyamines selectively in cancer patients but not in non‐cancer patients, suggesting that these changes may relate to tumor presence. We therefore studied the possible relationship between RBC polyamine levels and potential tumor growth induced by TPN. In addition, we attempted to control tumor growth during TPN with α‐difluoromethylornithine (DFMO), a suicide inhibitor of ornithine decarboxylase (ODC), in a fibrosarcoma‐bearing rat model. Rats in a control group received chow ad libitum for 3 weeks and their tumors grew exponentially. A restricted intake (RI) tumor‐bearing group received 8 g chow per day per rat; this produced malnourished rats in which tumor growth significantly slowed. The third group (RI → TPN) received the RI diet for 2 weeks and TPN for 1 week, which resulted in an increase in tumor growth. The last group (RI → TPN + DFMO) received a 2‐week RI regimen and 1‐week TPN plus DFMO regimen, which inhibited tumor growth to the level of the RI group due to the addition of DFMO (1 g/kg/day). Although the addition of TPN to the RI regimen markedly increased tumor ODC activity, as well as tumor putrescine and RBC putrescine levels, the addition of DFMO to the RI → TPN regimen entirely abolished these increases. Despite DFMO treatment, liver ODC activity in RI → TPN + DFMO group was unaffected. The plasma albumin level, an indicator of host nutrition, of the RI → TPN + DFMO group was significantly higher than that of the RI group. Liver, spleen, kidney and total body weights of the RI → TPN or RI → TPN + DFMO group were significantly higher than those of the RI group. These results indicate that TPN can enhance tumor growth in malnourished hosts and that the addition of DFMO to TPN can effectively control this TPN‐enhanced tumor growth, leading to preferential nutritional repletion of the host.
Molecular and cellular characterization of drug resistant hamster cell lines with alterations in ribonucleotide reductase
Authors: Tagger Aaron Y. , Wright Jim A.
Published: February 2007

Ribonucleotide reductase consists of 2 protein components frequently called M1 and M2. Hydroxyurea specifically inhibits DNA synthesis by interacting with the M2 protein and destroying a unique tyrosyl‐free radical. We have carried out a molecular and cellular characterization of 2 Chinese hamster ovary cell lines exhibiting either low (HNR‐AT) or relatively high (HR‐R2T) resistance to the cytotoxic effects of hydroxyurea. Both drug‐resistant lines have an increased level of ribonucleotide reductase activity. EPR measurements for tyrosyl‐free radical content and studies with M1‐specific antibodies indicated that the elevation in enzyme activity was entirely due to an increase in the M2 component. Studies with M1 cDNA showed that both drug‐resistant cell lines contained a wild‐type level of M1 mRNA and a wild‐type M1 gene copy number. Studies with M2 cDNA indicated that the 2 drug‐resistant lines possessed elevated levels of M2 message that could explain the observed increase in M2 component. The elevation of M2 mRNA in the most resistant line, HR‐R2T, was due to an increase in M2 gene copy number. The low resistant cell line, HNR‐AT, exhibited a wild‐type M2 gene copy number, indicating that the increase in M2 gene message occurred through a process other than gene amplification. Enzyme kinetic studies with partially purified preparations from both drug resistant lines showed reduced sensitivity to hydroxyurea and to the negative allosteric effector, dATP. In addition to hydroxyurea, HR‐R2T cells were also resistant to several other drugs whose site of action is the M2 component. Furthermore, HR‐R2T cells were not cross‐resistant to colchicine or puromycin, suggesting that hydroxyurea‐resistant cells do not share the multi‐drug resistance phenotype, which is frequently associated with cross‐resistance to these drugs.
Immunosuppressive activity of human neuroblastoma tumor gangliosides
Authors: Floutsis Grace , Ulsh Lisa , Ladisch Stephan
Published: February 2007

Gangliosides are shed in substantial amounts by some tumors, including human neuroblastoma, and these molecules modulate experimental tumor formation in vivo. We now demonstrate that neuroblastoma tumor gangliosides have potent immunoregulatory activity. Gangliosides of every one of 17 tumors studied were highly inhibitory for the normal in vitro human lymphoproliferative responses to the soluble antigen, tetanus toxoid; 30 nmol ganglioside/ml caused 43% to >99% inhibition and the mean concentration causing 50% inhibition was only 17.3 nmol/ml. Furthermore, gangliosides isolated from clinically more aggressive tumors (Stage III or IV) were up to twice as immunosuppressive as those of the generally less aggressive tumors (Stage I or II) (p<0.05). Taken together with the lack of immunosuppressive activity of normal plasma gangliosides, the potent activity of neuroblastoma gangliosides supports the hypothesis that one mechanism by which these shed molecules may act to enhance tumor formation in vivo is through abrogation of the host cellular immune response at the site of tumor formation.
Coffee, alcohol, smoking and cancer of the pancreas: A case‐control study
Authors: Clavel Françoise , Benhamou Ellen , Auquier Ariane , Tarayre Michèle , Flamant Robert
Published: February 2007

A hospital case control study on smoking, alcohol and coffee consumption as risk factors for pancreatic cancer, in which 161 cases were matched to 268 control patients, was conducted in France between 1982 and 1985. The results showed no association between tobacco or alcohol consumption and cancer of the pancreas, whereas coffee consumption was associated with an increased risk [OR of 2 or more cups per day vs. less: 2.27 (1.11–4.64) and 1.45 (0.82–2.55) among females and males respectively]. A dose‐response relationship was observed with coffee consumption in both sexes, stronger among females than among males: the linear increase estimates were 2.00 (1.22–3.29) and 1.32 (0.91–1.92) respectively. No interaction was found between coffee and tobacco, whereas the effect of coffee appeared to be limited to non‐drinkers of alcohol.
Chemical carcinogen epstein‐barr virus (ebv) synergism: Ebv genome amplification and site‐specific mutation during transformation
Authors: Henderson Earl E. , Franks Carol , Fronko Gerald
Published: February 2007

When treated with chemical carcinogens, peripheral blood lymphocytes (PBLs) from normal adults or patients with acquired immunodeficiency syndrome (AIDS) were more readily transformed than non‐treated PBLs into immortalized lymphoblastoid cell lines (LCLs) by the Epstein‐Barr virus (EBV, FF41‐I). Chemical carcinogens also enhanced spontaneous transformation in both PBL populations. Co‐cultivation of lethally ultraviolet (UV)‐irradiated uninfected PBLs with EBV‐infected PBLs resulted in a dose‐related enhancement of transformation, providing evidence that enhancement is in part mediated by carcinogen‐induced diffusible trans‐acting factors. Analysis of the EcoR1 J region of resident EBV genomes showed that LCLs established from carcinogen‐treated PBLs frequently had EBV genome amplification higher than that seen in controls. Carcinogen‐induced EBV genome amplification was shown to be dose‐related. The organization of the terminal region of the EBV genome was analyzed in LCLs derived from carcinogen‐treated PBLs and compared to that of FF4I‐1 and B95‐8. LCLs established from N‐methyl‐N′‐nitroso‐nitrosoguanidine (NNNG)‐and aflatoxin B1‐treated PBLs frequently had 2 circular forms of the EBV genome and several linear forms varying by numbers of terminal repeats (TRs) at the 3′ and 5′ end. This is in contrast to the single episomal circular and linear form of the EBV genome found in the parent FF41‐1 and single episomal circular form in control FF41‐1‐carrying LCLs. Linear forms of the EBV genome were only found in FF41‐1‐transformed LCLs derived from carcinogen‐treated PBLs and were associated with the production of unusually large amounts of infectious EBV. These results demonstrate that chemical carcinogen‐mediated enhancement of transformation is accompanied by quantitative and qualitative alterations in the physical structure, organization and expression of the EBV genome which may in turn be the result of a carcinogen‐induced cellular SOS response.
Cellular interactions determining the production of collagenase by a rat mammary carcinoma cell line
Authors: Lyons J. Guy , Siew Kenneth , O'Grady Robert L.
Published: February 2007

The cellular interactions regulating the production of collagenase by a cell line derived from a spontaneously arising rat mammary carcinoma have been studied. The cell line, BC1, was grown permanently under defined serum‐free conditions, so that the poorly characterized and variable effects of serum on collagenase expression were avoided. Two stable subpopulations of cells present in BC1 cultures were defined as epithelioid cells (“E‐cells”) and myoepithelioid cells (“M‐cells”). These subpopulations differed in their morphology, pattern of growth and susceptibility to detachment from culture vessels by trypsin. Seven clones of M‐cells and 7 clones of E‐cells, obtained by the limiting dilution technique, were used to determine the cellular source of collagenase and the interactions which led to its expression. M‐cells displayed an absolute dependence on a soluble factor produced by E‐cells for their survival in vitro. The presence of both cellular types in culture was necessary for collagenase secretion to occur, E‐cells being the major source of enzyme in mixed cultures. A soluble factor produced by M‐cells was largely, if not completely, responsible for the induction of collagenase secretion by E‐cells. Clones representative of both subpopulations were tumorigenic in syngeneic host animals. These results suggest that the phenotypic diversity which occurs within populations of neoplastic cells may give rise to subpopulations of cells which display a more aggressive phenotype in coexistence than in isolation.