bluuebunny/crossref_metadata_2025 huggingface dataset:
A monoclonal antibody cibr17 recognizes a myoepithelium‐specific antigen in human mammary gland
Authors: Dempsey Peter J. , de Kretser Theonne A. , Brown Robert W. , Whitehead Robert H. , Jose David G.
Published: February 2007

A murine monoclonal antibody (MAb) CIBr17, raised against the human breast carcinoma cell line PMC42, reacts specifically with myoepithelial cells in normal human breast. This IgGI antibody recognizes a ∼ 110kDa glycoprotein that is expressed on the cell surface and junctional membranes of PMC42 mono‐layer cultures. The CIBr17 antigen is present in two major glycosylated forms with approximate pls of 5.2 and 5.5 respectively in PMC42 cells. The tissue specificity of CIBr17 was assessed on frozen sections of PLP‐fixed tissues by means of a 4‐layer immunoperoxidase technique. CIBr 17 has reacted with a variety of epithelium‐derived tissues and some smooth muscle cells. Within many epithelial tissues, CIBr17 has demonstrated specific staining of particular epithelial cell types. Within normal breast and most benign breast lesions, antibody CIBr17 stained only myoepithelial cells. No staining of luminal epithelium, basement membranes or stromal elements was observed. In sclerosing adenosis, CIBr17 stained areas of pronounced myoepithelial differentiation, while in duct epitheliosis variable staining of proliferating cells was observed. In breast carcinomas, CIBr17 demonstrated variable antigen expression. In most tumors, CIBr17 either did not stain any tumor cells or stained only a small number of tumor cells spread randomly throughout the tumor. In several ductal carcinomas, however, CIBr17 stained the majority of tumor cells.
Products of cells cultured from gliomas. IV. Extracellular matrix proteins of gliomas
Authors: McKeever Paul E. , Fligiel Suzanne E. G. , Varani James , Hudson Jerry L. , Smith David , Castle R. Lynn , McCoy J. Philip
Published: February 2007

Five primary and 3 established human glioma cell lines were cultured with ascorbate and examined for expression of extracellular matrix components. All lines except C6 expressed collagen as assessed by silver impregnation, immunofluorescence and lectin staining and expressed laminin and fibronectin. None expressed a lectin marker for endothelial cells. Both epithelial and mesenchymal collagens were expressed. While extracellular components of glioma lines resembled those of fibroblasts more closely than other cell types, subtle differences between gliomas and fibroblasts were present. These included more laminin and collagen type‐IV antigenic reactivity and more 11–12 nm diameter extracellular fibrils from individual gliomas, and slight differences in spectra of low‐molecular‐weight extracellular proteins assessed by gel elec‐trophoresis. One primary and two established glioma lines analysed for DNA content were aneuploid in contrast to diploid fibroblasts. Simultaneous expression of mesenchymal and epithelial markers suggests a dual differentiation potential of glioma cells. Results do not support an endothelial origin for cells cultured from gliomas.
Suppression of tumorigenicity by the cell‐cycle‐dependent control of cellular differentiation and proliferation
Authors: Wille John J. , Scott Robert E.
Published: February 2007

The experiments described in this report were designed to determine if suppression of tumorigenicity can be mediated by cell‐cycle‐dependent mechanisms that control cellular differentiation and/or proliferation in mesenchymal stem cells of the 3T3 T type. These cells were employed because they possess distinct, well‐characterized cell‐cycle‐dependent mechanisms to control both cellular differentiation and proliferation. To achieve our goal we developed by non‐mutagenic procedures 23 clonal variants of 3T3 T stem cells that expressed one of 4 distinct phenotypes for the regulation of cellular differentiation and proliferation. Six clones expressed combined defects in the control of differentiation and proliferation; 6 expressed intact mechanisms to control proliferation but defects in the control of differentiation; and 3 expressed intact mechanisms to control differentiation but defects in the control of proliferation. Finally, 8 clones expressed no detectable phenotypic defects in the control of either differentiation or proliferation. Once isolated and characterized, each of these clones was assayed for its tumorigenic potential. The results establish that clones which express combined defects in the control of differentiation and proliferation are highly tumorigenic. By contrast, tumorigenicity is markedly suppressed in clones that maintain the ability to control their proliferation or their differentiation. Furthermore, clones that maintained the ability to control both proliferation and differentiation showed no evidence of tumorigenicity. These data are interpreted to suggest that stringently regulated control of cellular differentiation and/or proliferation can act as a cancer suppressor mechanism.
A radiobiological comparison of human tumor soft‐agar clonogenic assays
Authors: West Catharine M. L. , Sutherland Robert M.
Published: February 2007

Radiation survival curves have been generated for 3 human tumor cell lines as a means of comparing and evaluating the validity of human tumor soft‐agar clonogenic assays. The assays investigated were the Hamburger‐Salmon, Courtenay‐Mills, Courtenay‐Mills plus additions, soft agar (no additions), and soft agar plus additions. The additions were formulated to supplement the media used in soft agar assays of primary ovarian and cervical carcinoma specimens. Supplementing the media with additions led to a 2‐ to 3‐fold increase in PE of CaSki cells but had no effect on the PEs of ME180 and OWI cells. Radiation survival curves were similar in all assays for CaSki and OWI but differed for ME180 cells. For ME180 cells, the Courtenay‐Mills and soft agar assays plus additions produced the most radioresistant curves (Do = 2.2 Gy); the cells were more responsive when assayed by the Hamburger‐Salmon method (Do = 1.5 Gy), and the soft agar and Courtenay‐Mills assays gave the most radiosensitive curves (Do = 1.2 Gy). These results demonstrate that the PE of human tumor cell lines may be increased with no effect on radiation survival; radiation survival may be altered without changes in PE and neither may be altered by applying modifications and supplements to existing clonogenic assays.
Augmentation of B16 melanoma lung colony formation in C57BL/6 mice having marked granulocytosis
Authors: Ishikawa Makoto , Koga Yutaka , Hosokawa Masuo , Kobayashi Hiroshi
Published: February 2007

The effect that polymorphonuclear leukocytes (PMN) may have on the metastatic colonization of tumor cells is controversial: some laboratories have reported that PMN can inhibit metastasis whereas others have shown an augmentation effect. We have exploited our finding that a particular fibrosarcoma (BMT‐II) transplanted subcutaneously into syngeneic C57BL/6 mice induces a progressive increase in the number of circulating PMN, to re‐examine this question. We used such “granulocytosis‐positive” mice as recipients of B16 melanoma cells to examine the influence of significant granulocytosis on the level of lung tumor colonies. The number of B16 melanoma lung colonies detected after intravenous (i.v.) injection was significantly higher in BMT‐II tumor‐bearing mice with granulocytosis than in control (non‐tumor‐bearing) mice. Retention of 125IUdR‐labelled B16 cells 24 hr after the i.v. injection was 3 to 10 times greater in mice with granulocytosis than in controls. Either simultaneous injection, or preinjection of PMN with B16 cells, increased the lung‐colonizing capacity of B16 melanoma cells. These results suggest that abnormally increased numbers of PMN in the peripheral blood, particularly in the lung circulation, can enhance the ability of tumor cells to colonize or metastasize.
Cancer incidence in Murcia, Spain, in 1982: First results from a population‐based cancer registry
Authors: Navarro Carmen , Perez‐Flores Domingo , Coleman Michel P.
Published: February 2007

This report presents the first findings of the Murcia Cancer Registry, a population‐based cancer registry set up in May 1981 in the Murcia region of southeast Spain (955,487 inhabitants). Descriptive epidemiological methods have been applied to study cancer incidence in 1982. The validity of cancer registration has been assessed for both completeness and accuracy. Altogether 1,987 cases were registered in 1982, the crude (all‐ages) annual incidence rates per 100,000 being 238 in males and 179 in females. Excluding non‐melanoma skin cancer, which seems to be incompletely registered, age‐standardized rates for Murcia are very similar to those of other registries in Spain in males, but lower in females. The risk was higher in males than in females for all sites and for the great majority of specific sites, especially larynx, oesophagus and bladder. The age‐standardized rate for cancer of the larynx was 26 times higher in men than in women. Lung cancer was the most common cancer in males: the risk was 8 times that in females. Lung cancer rates were higher, in both males and females, than in other Spanish registries. Cancer of the larynx was the second most common site in males when either truncated rates (35–64 years) or cumulative incidence rates up to 64 years of age were used. The age‐standardized rate (18 per 100,000) supports previous studies suggesting that the risk for this cancer in Spain and other Mediterranean countries is very high. The lung/larynx rate ratio in men was two. Cancer of the breast is the most common cancer among women, as in other registries in Spain and in most other countries. The age‐standardized rate (29.4 per 100,000) is lower than breast cancer rates elsewhere in Spain. This difference may be partly explained by incompleteness of ascertainment in Murcia. The incidence rate for cancer of the cervix uteri was 4.9 per 100,000, excluding carcinoma in situ. Despite the limitations of the data, cervical cancer incidence in Murcia is likely to be similar to that in other regions of Spain.
Characteristics of a cell line established from a patient with multiple osteosarcoma, appearing 13 years after treatment for bilateral retinoblastoma
Authors: Fodstad Øystein , Brøgger Anton , Bruland Øyvind , Solheim Oyvin P. , Nesland Jahn M. , Pihl Alexander
Published: February 2007

An osteosarcoma cell line, OHS, was established from a patient with multiple skeletal manifestations of osteosarcoma, developing after bilateral retinoblastoma. The tumor cells expressed sarcoma‐associated antigens and showed rapid growth in monolayers and as multicellular spheroids. They formed distinct colonies in soft agar, and subcutaneous tumors in nude mice. Morphological studies indicated that OHS cells had retained important characteristics of the cells of origin. No deletion of the retinoblastoma genes on chromosome 13q 14 could be demonstrated with the banding techniques used. However, cytogenetic studies revealed double minute chromosomes, as evidence of gene amplification, as well as translocations involving chromosomes 1,6,11 and 13. The OHS line can be used to study the genetic basis of tumor initiation and growth, and to elucidate factors predisposing for second primary cancers in retinoblastoma patients.
Studies in healthy human T‐cell‐leukemia lymphoma virus (HTLV‐I) carriers from the Caribbean
Authors: Matutes E. , Dalgleish A. G. , Weiss R. A. , Joseph A. P. , Catovsky D.
Published: February 2007

Six healthy relatives of 3 adult T‐cell leukemia lymphoma (ATLL) patients and 6 members of a Caribbean family immigrant to the UK have been investigated for the presence of HTLV‐I and expression of interleukin 2 (IL‐2) receptors. Serum antibodies to HTLV‐I were detected in all but 4 samples. Four to 10% of circulating cells from 3/4 seropositive donors studied displayed IL‐2 receptors (anti‐Tac+) and were shown to be convoluted lymphocytes by light microscopy morphology and immunoelectronmicroscopy. After 5 to 28 days in culture, cells from 4 seropositive donors reacted with monoclonal antibodies (MAbs) against the HTLV‐I core proteins, p19 and p24, and released retrovirus particles. Similar experiments with blood from 3 seronegative donors from the same families and 4 normal controls proved negative. Our findings indicate that seropositive individuals harbour the virus in a population of T‐lymphocytes which may then acquire receptors for IL‐2. These individuals are at risk of developing ATLL.
The epithelial cell surface antigen 17–1A, a target for antibody‐mediated tumor therapy: Its biochemical nature, tissue distribution and recognition by different monoclonal antibodies
Authors: Göitlinger Heinrich G. , Funke Ilona , Johnson Judith P. , Gokel Josef M. , Riethmüller Gert
Published: February 2007

The antigen defined by MAb 17–1A, raised against colorectal cancer cells and currently used in immuno‐therapy trials, is a 37 kDa protein containing N‐linked glycans as demonstrated by inhibition of glycosylation with tunicamycin. The 17–1A antigen (17–1A Ag) is broadly distributed in normal epithelial tissues and is also found in various types of carcinoma. Quantitative differences in expression between normal and malignant tissues were only apparent in gastric carcinomas. After immunizing mice with fresh colon carcinoma tissue, 4 MAbs were obtained that showed the same tissue reaction pattern as MAb 17–1A and recognized the 17–1A Ag as judged from precipitation and immunoblotting experiments. MAbs M72 and M74 reacted with an anti‐idiotypic serum directed against the original MAb 17–1A and were able to block 17–1A binding. In contrast, M77 and M79 are directed against a different epitope. This makes them potentially interesting for passive immunotherapy in regimens involving a combination of MAbs.
Enhancement of experimental metastasis by pretreatment of tumour cells with hydroxyurea
Authors: McMillan T. J. , Rao J. , Hart I. R.
Published: February 2007

The effect of treatment with hydroxyurea (HU), on subsequent experimental metastasis formation by cells of 3 murine melanoma lines has been examined. In vitro treatment of B16‐F1, B16‐F10and K‐1735‐clone 19 cells with 0.1 mM or 0.3mM HU, followed by a period of recovery in drug‐free medium, resulted in a significant increase in the number of lung nodules formed in syngeneic mice following i.v. injection of the cells. The maximum effect obtained was observed when cells were injected 6 hr after removal of HU and it occurred in spite of the cytotoxicity of the doses used. Six hours after release from treatment with 0.3 mM HU cells were synchronized in the G2 phase of the cell cycle but the consequent increase in cell volume was not responsible for increased metastasis through enhancement of tumour‐cell arrest, since lodgement of 51Cr‐labelled, HU‐treated cells was no greater than that of control cells. The results obtained suggest that the chemotherapeutic agent HU may facilitate tumour progression via a direct action on neoplastic cells.
Expression of protooncogenes in murine osteosarcomas
Authors: Schön A. , Michiels L. , Janowski M. , Merregaert J. , Erfle V.
Published: February 2007

The expression of 7 protooncogenes (c‐sis, c‐abl, c‐mos, c‐bas, c‐Ki‐ras, c‐fos, c‐myc) was examined in transplants and established cell lines from spontaneous and radiation‐induced murine osteosarcomas. The transplant tumors were compared with different tissues, particularly skeletal tissue (sternum), and the osteosarcoma cell lines with fibroblast lines from the same mouse strains. C‐sis was expressed above the level of controls in 2 osteosarcomas (TV, Os5). Three osteosarcomas showed over‐expression of c‐abl (TVK, DOS, Os5), c‐bas (DOS, Os5 and V893) and c‐fos (TVK, DOS, Os5), and 4 osteosarcomas showed over‐expression of c‐Ki‐ras (TVK, DOS, Os5, Os16) and c‐myc (TVK, DOS, TV, Os5). C‐mos expression was not observed under the conditions used. One cell line (Os5) showed an altered transcript (1 kb transcript of c‐fos). Apart from the relatively frequent increase in expression of the c‐myc and c‐ras‐family, there was no indication that any particular protooncogene or combination of protooncogenes was associated with murine osteosarcomas.
Gut‐associated lymphoid tissue and 1,2‐dimethylhydrazine intestinal tumors in the rat: An histological and immunoenzymatic study
Authors: Martin M. S. , Hammann A. , Martin F.
Published: February 2007

The association between chemically‐induced intestinal carcinoma and gut lymphoid patches was studied in 20 male Sprague‐Dawley rats 7 months after the first of 16 weekly injections of 1,2 dimethylhydrazine (DMH). The lymphoid patches of DMH‐treated rats and of 14 untreated control animals were systematically studied histologically on sections of “swiss‐rolled” whole intestine. It was found that 78% of the small‐intestine carcinomas and 73% of the colorectal carcinomas were associated with intestinal lymphoid patches. Furthermore, misplaced and often atypical glandular crypts were often found in the parafollicular or interfollicular areas of lymphoid patches, in treated as well as in control animals. These glands could be the origin of the lymphoid‐patch‐associated carcinoma. Immunohistological staining with monoclonal antibodies (MAbs) against T‐lymphocyte antigens or anti‐IgM serum labelling B lymphocytes clearly localized early carcinoma and atypical glands in the T‐dependent, interfollicular and parafollicular area of lymphoid follicles. An MAb directed against la‐antigen stained some well‐differentiated carcinomas and some atypical glands found in control rats. On the other hand, lymphoid patches, when not invaded by a carcinoma, were not modified in their number, size, morphology or cellular composition in DMH‐treated rats as compared to control animals.
Post‐exposure treatment with monoclonal antibodies in a retrovirus system: Failure to protect cats against feline leukemia virus infection with virus neutralizing monoclonal antibodies
Authors: Weijer Kees , Uytdehaag Fons G. C. M. , Jarrett Oswald , Litz Hans , Osterhaus Albert D. M. E.
Published: February 2007

We have attempted to protect kittens against oronasal infection with FeLV (strain A/Glasgow‐I) by treatment with a mixture of two virus‐neutralizing (VN) MAbs (IgGI, K) directed against the same epitope of the viral glycoprotein gp70. Ten SPF 9‐week‐old kittens were infected on day 0 with 106 ffu FeLV and subsequently inoculated i.m. with MAbs every 2 days over a 20‐day period at different times after infection. The results clearly show that no protection was achieved. It is unlikely that the amount of VN antibodies, the mode and route of their application or the infectious dose of FeLV used can account for the failure to protect cats against infection. Other possibilities which may explain the lack of protective effect are that (i) the restricted epitope specificity of the MAb preparation used may have led to selection of neutralization‐resistant virus mutants, or that (ii) other mechanisms than virus neutralization (complement‐mediated lysis, antibody‐dependent cell cytotoxicity), that may be involved in protection, function less efficiently with MAb. However, in the light of our finding that an early anti‐idiotypic response is observed in all cats following administration of the MAb preparation, the rapid clearance of anti‐FeLV MAb from the circulation is a more likely explanation. The data presented support our hypothesis that by administration of MAb—as compared to polyclonal antibody—a more vigorous anti‐idiotypic response is elicited due to the presentation of only a limited set of idiotopes. This potential drawback of rapid clearance of MAbs as a consequence of an anti‐idiotypic response might be overcome by the use of mixtures of MAbs resulting in a more heterogeneous set of idiotypic determinants.
Molecular expression of epitopes recognized by monoclonal antibodies HMFG‐1 and HMFG‐2 in human breast cancers: Diversity, variability and relationship to prognostic factors
Authors: Turnbull J. E. , Baildam A. D. , Barnes Diana M. , Howell A.
Published: February 2007

Epitopes recognised by the monoclonal antibodies HMFG‐1 and HMFG‐2 are found on glycoprotein components in human breast cancers. This study used immunobiotting techniques to ascertain their molecular diversity, assess their relationship to known prognostic factors, and investigate their expression in sequential samples of breast tumours from individual patients. Both epitopes were expressed on components of a wide variety of molecular weights (HMFG‐1, 130 to 450kDa; HMFG‐2,90 to 450kDa). The HMFG‐2 epitope was expressed more frequently on components of <200kDa (p < 0.0001). Progesterone receptors (PR), small tumour size and low histological grade correlated significantly with HMFG components ⩾300kDa. Higher staining intensity was associated with increased likelihood of PR positivity. Paired sequential samples were taken, with a median interval of 8 days, from 38 patients, 23 of whom were administered tamoxifen. In the majority of tumours profiles of expression of components carrying the epitopes were identical in both samples (HMFG‐1, 30/38; HMFG‐2, 22/38). Overall the results suggested that there was no consistent relationship between the differences observed and tamoxifen administration. We conclude that expression of the HMFG‐1 and HMFG‐2 epitopes is relatively constant in most tumours, but variable (and possibly subject to modulation) in others, and that their expression, particularly on high molecular weight components, is related to factors associated with good prognosis (PR, small size, low grade), and may be of independent prognostic value.
Radiosensitization of human tumor cells by alpha‐difluoromethylornithine
Authors: Courdi A. , Milano G. , Bouclier M. , Lalanne C. M.
Published: February 2007

The effect of polyamine depletion on the radiosensitivity of a human tumor cell line was investigated. CAL 18 A cells, derived from a breast carcinoma, were incubated with alpha‐difluoromethylornithine (DFMO)—a specific and irreversible inhibitor of ornithine decarboxylase (ODC)—at a 1 mM or 10‐mw concentration for either 1 hr or 24 hr and irradiated thereafter. Survival curves of exponentially growing cells revealed a moderate but significant enhancement of radiosensitivity as compared to untreated irradiated cells. Maximum radiosensitization was observed at a concentration of 10 mw after I hr incubation. Plateauphase cells were used to study the effect of polyamine inhibition on repair of radiation‐induced potentially lethal damage (PLD). DFMO enhanced the radiation response and significantly inhibited PLD repair in these cells. Measurement of ODC indicated that this enzyme was markedly inactivated upon brief incubation of CAL 18 A cells with DFMO, reflecting a depletion of polyamine synthesis. These results extend findings that have demonstrated enhancement of drug‐induced cytotoxicity, and raise the possibility of clinical use of this substance for potentiation of radiation response.
Low frequency of NK‐cell progenitors and development of suppressor cells in IL‐2‐dependent cultures of spleen cells from low NK‐reactive SJL/J mice
Authors: Migliorati Graziella , Herberman Ronald B. , Riccardi Carlo
Published: February 2007

Studies were performed to determine the basis for low NK activity in the spleens of SJL/J mice. In contrast to substantial boosting by IL‐2 or IFN of NK activity of spleen cells from high NK‐reactive strains of mice, no detectable effect of these citokines on SJL spleen cells was seen. When SJL spleen cells were cultured for 7 days in the presence of IL‐2, the frequency of proliferating cells was comparable to that of other strains of mice. However, the SJL spleen cells showed a frequency of NK‐cell progenitors which was at least 50 times lower than that of the CBA/J spleen cells. In addition to having no detectable effector‐cell activity, the cultures of SJL spleen cells contained suppressor cells which were able to inhibit the NK activity of spleen cells from other strains of mice. These suppressor cells did not adhere to plastic or nylon wool and were found in low‐density fractions after Percoll density gradient centrifugation. The cultured SJL spleen cells had a high percentage of cells capable of binding to NK‐susceptible target cells, which was similar to that seen in lytic cultures from other strains of mice. Thus, the suppressor activity may be attributable to competitive inhibition of the interaction of effector cells with target cells. Although several of the characteristics of suppressor cells were similar to those of cultured effector cells; they may not represent inactive or pre‐NK cells since their progenitors were Thyl+ and Asialo GM whereas the progenitors of cultured effector cells in high NK strains were Thy I−. and GM. The ability to eliminate the progenitors of the suppressor cells by pretreatment of spleen cells with anti‐Thyl plus C' also suggested that the low or undetectable NK activity of the cultured SJL cells is not attributable to suppression but may be due to an inherent deficit of NK cells.
Chromosomal study demonstrating the clonal evolution and metastatic origin of a metachronous colorectal carcinoma
Authors: Muleris Martine , Salmon Rémy Jacques , Dutrillaux Bernard
Published: February 2007

Detailed cytogenetic studies were performed on 3 samples of a metachronous rectal carcinoma. Two samples were obtained from the primary tumor, and one from a secondary growth which arose 10 months after surgical removal of the primary. All 149 R‐banded metaphases analysed were abnormal and most likely derived from the same modified karyotype: 45, XY,−1, −18, +20, der(6) t(l;6) (q21.100; q22.3), i(17q). These data are consistent with our previous findings that the loss of chromosome 18 and of the short arm of chromosome 17 may be the primary chromosomal changes associated with carcinoma of the large bowel. From all the karyotypes observed, a typical clonal evolution could be reconstructed, indicating that the second tumor was indeed metastatic from the first one, based on similar chromosome markers. An identical secondary chromosomal anomaly, i.e. gain of chromosome 8 or X, occurred independently twice in two different cell populations during the evolution of this tumor.
Effect of tunicamycin on synthesis and secretion of carcinoembryonic antigen by human colonic adenocarcinoma cells
Authors: Miura Soichiro , Kim Young S.
Published: February 2007

The effect of the glycosylation inhibitor, tunicamycin, on synthesis and secretion of the membrane‐associated glycoprotein carcinoembryonic antigen (CEA), was studied in the LSI74T human colon cancer cell line. Tunicamycin treatment inhibited total cellular glycoprotein synthesis but did not affect CEA levels of cellular homogenate, membrane or cytosol fractions as determined by enzyme immunoassay. Control cells metabolically labelled with 3H‐glucosamine, 3H‐leucine or 35S‐cysteine exhibited membranous and extracellular (i.e. secreted) CEA with an MW of 200 kDa as judged by SDS‐gel electrophoresis following immuno‐precipitation. However, in the tunicamycin‐treated cells several forms of CEA with lower MWs and representing molecules with decreased glycosylation could be detected in addition to the original CEA molecule of 200 kDa present in control cells. The rates of synthesis, secretion and turnover of the lower‐molecular‐weight forms of poorly glycosylated CEA that appear after tunicamycin treatment are similar to those of CEA in control cells. These data suggest that the carbohydrate portion of the CEA molecule is not essential in synthesis, incorporation into the membrane, and secretion of CEA by colon cancer cells in vitro.
Induction of thymic lymphosarcomas in C57BL/6 mice after inoculation of weakly oncògenic viruses associated with a sub‐leukemogenic radiation exposure (1.75 GY × 2)
Authors: Galiay M. , Leorand E. , Aster‐Gin T. , Rollet C. , Guillemain B. , Duplan J. F.
Published: February 2007

B‐ecotropic retroviruses arise frequently in old or irradiated C57BL/6 mice as a consequence of a genetic recombination between endogenous eco‐ and xenotropic retroviruses. They are weakly oncogenic and express a very low tropism for thymic cells. However, their activation by X‐rays and the subsequent insertion of new proviral sequences in the cell genome of in vivo‐ and in vitro‐passaged tumors suggest that they might play a role in radioleukemogenesis. To study this possibility, a cloned B‐ecotropic virus (1223) was injected into C57BL/6 mice subjected to a subleuke‐mogenenic irradiation which induses only 7% of thymic lymphosarcomas (TL). When it was injected prior to or after irradiation, 1223 induced respectively 31 % and 19% of TL. The incidence of TL in the different groups closely correlated with virus expression in hemato‐poietic tissues during the preleukemic period. Thus, irradiation seems to amplify bone marrow (BM) and thymic cell populations) which play a decisive role in viral expression. A recombinant provirus (presumably the injected 1223) was detected in the genomic DNA of all tumors tested irrespective of the inductive protocol. BM restoration, which does not inhibit TL produced by highly oncogenic passaged viruses, but prevents the development of TL induced by 4 doses of 1.75 Gy, also provided strong protection in the present experiments. The present data support the hypothesis whereby weakly oncogenic B‐ecotropic viruses similar to those activated by radiation might be involved in the development of TL.
Effect of some proliferative and environmental factors on the toxicity of mitomycin C to tumor cells in vitro
Authors: Rockwell Sara
Published: February 2007

Mitomycin C (MC) was more toxic to EMT6 mouse mammary tumor cells in vitro under hypoxia than under aerobic conditions. This was evidenced both in survival curves defining the toxicity of treatment with a constant dose of MC given for different periods of time and in survival curves defining the effect of a 1‐hr treatment with different concentrations of MC. Cultures preincubated for different periods from 1 to 6 hr in hypoxia all had similar MC sensitivities. In contrast, cultures preincubated in hypoxia for 4 hr then “reoxygenated” before MC treatment had the same sensitivities as cultures which had never been hypoxic. This shows that the oxygenation at the time of MC exposure, rather than the preincubation protocol, was the parameter determing cell sensitivity. Exponentially‐growing (proliferating) and plateau‐phase (quiescent) cultures had similar MC survival curves; neither type of culture repaired potentially lethal damage when held for up to 24 hr in HBSS after MC treatment. The sensitivity of the cells increased as the pH of the culture medium was decreased to low values (pH 7.0–6.0), but extracellular pH had no significant effect on the cytotoxicity of MC over the physiologic range (7.0–7.4). These data suggest that differences in the metabolic characteristics of cells that are hypoxic and aerobic during MC treatment, rather than perturbations of the cell proliferation patterns, the PLDR capacity of the cells, or the extracellular pH during the hypoxic incubation, are responsible for the different sensitivities of aerobic and hypoxic cells to MC in vitro.
Red blood cell polyamine levels and host toxicity during continuous alpha‐difluoromethylornithine infusion
Authors: Ota David M. , Grossie V. Bruce , Ajani Jaffer A. , Stephens L. Clifton , Nishioka Kenji
Published: February 2007

The dose effects of continuous alpha‐difluoromethylornithine (DFMO) infusion on red blood cell (RBC) polyamine levels, host toxicity and tumor growth were determined. Male rats with and without a transplantable methylcholanthrene‐induced sarcoma received intravenously either 0.45% NaCI or DFMO at 500 mg, 1,000 mg, or 2,000 mg/kg body wt/day for 6 or 12 days. Dose‐related inhibition of tumor growth was noted after the 12‐day treatment. There were no changes in host carcass weight, food intake, plasma albumin, hematocrit or white blood cell counts. Platelet supression was associated with the 1,000‐ and 2,000‐mg doses with the 12‐day treatment. Morphometry of the small intestine revealed mild but significant shortening of villi in the duodenum and jejunum at the 2,000‐mg dose, but none of the animals developed diarrhea. The 500‐mg DFMO dose reduced the rate of tumor growth without inducing platelet suppression or altering intestinal morphology. A decrease in RBC putrescine levels was noted at all doses. RBC spermidine levels increased with the 500‐mg dose. RBC spermine levels were higher at all doses compared with controls. These results suggest that thrombocytopenia is the major dose‐limiting side‐effect of continuous DFMO infusion but does not occur at a dose of 500 mg/kg body wt/day.
IL‐2‐ and IL‐2‐R‐ independent proliferation of T‐cell lines from adult T‐cell leukemia/lymphoma patients
Authors: Katoh Taiji , Harada Takayuki , Morkawa Shigeru , Wakutani Tadao
Published: February 2007

Human T‐cell leukemia/lymphoma virus 1 (HTLV‐1) is known to be associated with adult T‐cell leukemia/lymphoma (ATL) as an etiological agent. The mechanism of leukemogenesis by HTLV, however, is still obscure. Two hypotheses have been proposed concerning abnormalities in 1L‐2 production and its receptor (Tac antigen) expression based on the experimental observations of 1L‐2‐dependent ATL cell lines. In this study, we examine these hypotheses by using 3 leukemic T‐cell lines from 3 Japanese patients with ATL. These cell lines were cultivated and established without addition of 1L‐2 to the culture medium. Cell‐surface phenotype analysis by immunofluorescence with monoclonal antibodies (MAbs) and 1L‐2 binding assays revealed that one of the ATL cell lines, HPB‐ATL‐2, expresses only a minimal amount of 1L‐2 receptor (1L‐2‐R) on the cell surface and binds less radiolabelled human recombinant 1L‐2 than the other highly Tac‐positive cell lines. Expression of Tac antigen in all ATL cell lines was not affected by 1L‐2, anti‐Tac MAb or the tumor‐promoter phorbol ester in the culture medium. The culture supernatant from these cell lines showed no 1L‐2 activity toward Con‐A‐stimulated human peripheral blood lymphocytes, and their growth was not affected by additional 1L‐2 in cultures. 1L‐2‐independent growth and constitutive expression of its receptors on the cell surface were evident in our ATL cell lines. However, dense expression of 1L‐2 receptors was not essential for stimulation of leukemic proliferation of T cells by HTLV‐I. Trans‐activation of the PX″ gene product of HTLV‐I for activation of 1L‐2‐R gene might not be coincidentally associated with stimulation for cell proliferation.
Organ specificity of metastatic tumor colonization is related to organ‐selective growth properties of malignant cells
Authors: Nicolson Garth L. , Dulski Kim M.
Published: February 2007

In cancers such as malignant melanoma, tumor spread or metastasis occurs preferentially to certain organ sites. Mouse B16 melanoma cell sublines that have been selected sequentially in vivo for enhanced blood‐borne colonization of lung, brain, or ovary were tested for their survival and growth stimulation in vitro by soluble factors released from suspensions of mouse lung, brain, liver, ovary or kidney tissues. In general, the growth rate of lung‐colonizing B16 cells was stimulated by high concentrations of lung‐tissue‐derived factors significantly more than by factors from the other tissues, whereas the growth rate of ovary‐colonizing B16 cells was stimulated by ovary or lung‐tissue‐derived factors significantly more than by factors from the other tissues. In contrast, the growth of brain‐colonizing B16 cells was not stimulated by factors released from brain tissue. When it occurred, stimulation of B16 cell growth by factors released from mouse organ tissues was dose‐dependent. Liver tissue factors, and at high concentrations kidney tissue factors, inhibited cell growth of the B16 sublines, an inhibition correlating with the low potential of B16 cells to colonize liver and kidney in vivo. In addition to preferential target‐organ cell adhesion found previously with B16 sublines (Nicolson et al., 1985a), the present results suggest that metastasis to specific organ sites is also dependent on the survival and growth of B16 cells affected by soluble organ‐derived factors.
Molecular and immunological evidence of B‐cell commitment in “null” acute lymphoblastic leukaemia
Authors: Foa R. , Migone N. , Basso G. , Cattoretti G. , Pizzolo G. , Lauria F. , Casorati G. , Giubellino M. C. , Capuzzo F. , Cantu‐Rajnqldi A. , Lusso P. , Carbonara A. O. , Gavosto F.
Published: February 2007

The DMA configuration of the immunoglobulin (Ig) heavy and light chain genes and the expression of B‐ cell‐related markers were evaluated in 13 cases of non‐ T, non‐B, non‐common (“null”) acute lymphoblastic leukaemia (ALL). A rearrangement of the Ig heavy‐ chain gene was found in all cases studied; in 5 of these a structural reorganization of the K or Λ light chain gene was also demonstrated. Leukaemic cells from 10 of the 13 cases analysed showed one or more B‐cell antigens, the expression of which followed a sequential order of presentation (OKB2, B4, BA‐1, B1). The B‐cell commitment was confirmed by means of a sensitive immunoperoxidase assay which revealed a weak expression of the common ALL (cALL) antigen in 7/10 cases tested, which were all cALL‐negative by conventional immunofluorescence techniques. These findings suggest that in “null” ALL the neoplastic cells show molecular and immunological evidence of B‐cell differentiation and that most cases may indeed be characterized by “early” cALL with a very low density expression of the cALL antigen. This was further documented in one case in which the expression of the cALL antigen (and of other B‐cell markers) could be induced after exposure to 12‐O‐tetradecanoylphorbol‐ 13‐acetate (TPA). The presence in a few cases of myeloid features, particularly when the cALL antigen could not be demonstrated by the immunoperoxidase assay, suggests that the leukaemic process may sometimes involve a very early progenitor cell capable of both lymphoid and myeloid phenotypic differentiation. The heterogeneity of “null” ALL documented by this study may help to explain the variable clinical course and prognosis of these patients.
Thyroid function and the incidence of breast cancer in Hawaiian, British and Japanese women
Authors: Thomas B. S. , Bulbrook R. D. , Goodman Madeleine J. , Russell M. J. , Quinlan Michelle , Hayward J. L. , Takatani O.
Published: February 2007

Serum‐free thyroxine (FT4) concentrations are lower in Hawaiian and Hawaiian Caucasian women than in Hawaiian Japanese, Hawaiian Filipino, Hawaiian Chinese, and English and Japanese mainland women. There is a high inverse correlation between FT4 and risk of breast cancer in these ethnic groups. Thyroid‐ stimulating hormone (TSH) concentrations, which are inversely correlated with FT4, generally show the same relationship.
Long‐term use of oral contraceptives and risk of invasive cervical cancer
Authors: Brinton Louise A. , Huggins George R. , Lehman Herman F. , Mallin Katherine , Savitz David A. , Trapido Edward , Rosenthal Jeanne , Hoover Robert
Published: February 2007

To evaluate the relationship between use of oral contraceptives and risk of invasive cervical cancer, a case‐control study involving 479 patients and 789 population controls was undertaken in 5 geographic regions of the US. Initially, the relationship was obscured by confounding variables, particularly the interval since last Pap smear. Control for this variable as well as for sexual and sociodemographic factors revealed an RR of 1.5 overall, with long‐term users (5 or more years) being at a 2‐fold higher risk than non‐users. Pill associations prevailed for both adenocarcinomas and squamous‐cell tumors, and risks were highest for those using pills containing high estrogen potencies. In addition, there was some evidence that pill associations were most pronounced among women who had never used barrier methods of contraception or who had histories of genital infections, suggesting that oral contraceptives may act as co‐carcinogens with transmisible agents. Our findings provide further evidence that long‐term use of oral contraceptives may have a carcinogenic effect on cervical epithelium, but emphasize the need for careful evaluation of confounding influences.
Growth of human mammary carcinoma cells from biopsy specimens in serum‐free medium on extracellular matrix
Authors: Biran S. , Vlodavsky I. , Fuks Z. , Lijovetzky G. , Horowitz A. T.
Published: February 2007

A method developed for the initiation and maintenance in primary culture of human normal mammary epithelial cells was adopted for the growth of epithelial cells from 45 primary human breast tumors. The cells were grown on a naturally produced extracellular matrix (ECM) or on regular tissue culture plastic in a serum‐free medium containing growth supplements and high‐density lipoprotein (HDL). Successful enzymatic dissociation of the tumor biopsy into organoid structures and cell aggregates was crucial for subsequent cell attachment and growth. Fifty‐five percent of the biopsy specimens were successfully dissociated and 87% of these gave rise to actively dividing epithelial cells forming monolayer cultures. In contrast, only 21% of the biopsies which were not optimally dissociated yielded growing cultures. Variations in sample size, duration of enzymatic digestion, and tumor composition affected the outcome of tumor dissociation. Omission of serum from the culture medium prevented the growth of fibroblasts, while plating on ECM greatly improved and in some cases was essential for cell attachment and subsequent outgrowth. The epithelial nature of the cells was verified by their cuboidal and closely apposed morphology and positive staining with antikeratin antibodies. The growth and subculture requirements and the expression of the B38.1 tumor marker were compared in human mammary epithelial cells derived from solid tumors, pleural effusion and normal breast tissue.
Identification and localization of urokinase‐type plasminogen activator in human NK‐cells
Authors: Carpén O. , Saksela O. , Saksela E.
Published: February 2007

We have studied the presence of plasminogen activators in large granular lymphocytes and other peripheral blood cells. After immunofluorescence staining with polyclonal antiserum against urokinase‐ type plasminogen activator, the majority of LGLs showed granular staining which was located in Golgi‐ derived vesicles. LGLs were negative for tissue‐type activator. The presence of only urokinase‐type PA in LGLs was also confirmed by determining the molecular weight of the intracellular activator and by immunoblotting the antigen from solubilized cell preparations. Monocytes and granulocytes were more intensely stained with anti‐u‐PA than LGLs. In LGL/ K562 cell conjugates the fluorescence was often located close to the contact area and the vesicular fluorescence polarized during conjugate formation. Inhibitors of PA and other serine proteinases are known to abolish NK‐cell activity. We now show that they affect a later stage than programming for lysis in the cytotoxic action, suggesting a role for u‐PA or other serine proteases in the lethal‐hit stage of NK activity.
Cytomorphologic evaluation of the neoplastic potential of 28 cell culture lines by a panel of diagnostic cytopathologists
Authors: Boone Charles W. , Sanford Katherine K. , Frost John K. , Mantel Nathan , Gill Gary W. , Jones Gary M.
Published: February 2007

A panel of 7 diagnostic cytopathologists, i.e., physicians trained to diagnose the malignant potential of human cells in Papanicolaou‐stained smears, was asked to evaluate two sets of microscope slides of stained coverslip preparations of 28 cell culture lines, 15 of which were neoplastic. Slide Set I consisted of 13 pairs of cell lines, one member of each pair being non‐ tumorigenic and the other tumorigenic; the lines were of mouse (9 pairs), rat (3 pairs), and human (1 pair) origin. Slide Set II contained 4 human lines: one lung cancer, one melanoma, and two fibroblast lines. Of a total of 114 diagnostic decisions by the panel, 88 were correct (66/86, 77%) in choosing which member of a pair was neoplastic and 22 were correct (22/28, 79%) in choosing whether a given individual human line was or was not neoplastic. Two members of the panel were correct more frequently, with 16/17 (94%) correct diagnoses, each. Five nuclear morphologic criteria of malignancy used by cytopathologists were prominent in the tumorigenic lines: altered chromatin pattern characterized by increasing size of chromatin granules and chromatin clumping, sharp angularity of large nucleolar and/or chromocenter borders with spicule formation (pointed projection), irregular parachromatin clearing (increase in the clarity of the clear spaces between chromatin threads, granules, and clumps), uneven thickness of chromatin at the nuclear border, and variability in nuclear size and shape from cell to cell. These markers of neoplastic transformation, when added to those previously reported, should increase overall accuracy in the diagnosis of neoplastic transformation of mammalian cells in culture.
Tar yields of cigarettes and the risk of oesophageal cancer
Authors: La Vecchia Carlo , Liati Paola , Decarli Adriano , Negrello Ivano , Franceschi Silvia
Published: February 2007

The relationship between cigarettes with varying tar yields and the risk of oesophageal cancer was evaluated using data from a hospital‐based case‐control study conducted in Northern Italy on 129 histologically confirmed cases and 426 controls with acute, non‐ neoplastic or digestive diseases unrelated to tobacco or alcohol consumption. Compared with never‐smokers, the relative risks of developing cancer of the oesophagus were 2.9 for subjects who smoked mainly middle‐ or low‐tar (< 22 mg) cigarettes and 8.9 for those smoking high‐tar cigarettes (⩾ 22 mg).

The difference between the two categories was evident among ever‐smokers and only current smokers, was not explained by adjustment for the major covariates of interest (social class, alcohol consumption and dietary indicators), and persisted when allowance was made for duration of smoking and number of cigarettes smoked per day by means of multiple regression analysis. The present findings suggest that the relation between tar deliveries of cigarettes and risk may be even more marked for oesophageal than for lung cancer. Further, they have important public health implications, in consideration of the current relatively high tar yields of Italian cigarettes, particularly in a few areas of north‐eastern Italy where death certification rates from cancer of the oesophagus are among the highest in Europe. Nonetheless, in this study, smokers of prevalently low‐ to mid‐tar cigarettes still did experience a significantly higher oesophageal cancer risk than life‐long non‐smokers.