bluuebunny/crossref_metadata_2025 huggingface dataset:
Expression of a monoclonal antibody‐defined liver‐associated antigen in normal rat hepatocytes and hepatocellular carcinoma cells
Authors: Holmes C. H. , Gunn Barbara , Austin E. B. , Embleton M. J. , Baldwin R. W.
Published: February 2007

In order to examine changes in the expression of normal cellular antigens during hepatocarcinogenesis, we have developed and characterized a monoclonal antibody detecting an antigen which is particularly associated with adult rat hepatocytes. The antibody showed no reactivity with a range of freshly‐prepared normal syngeneic adult rat cell types, but showed strong reactivity with hepatocytes derived from several rat strains in antibody binding tests. Immunoperoxidase staining of sections of normal rat liver showed that the antigen was distributed throughout hepatocytes within the liver, but did not stain cells other than hepatocytes. The antigen detected by this monoclonal antibody was not detectable on a number of transplanted and primary dimethylaminoazobenzene‐induced hepatomas. Preliminary data indicated that this monoclonal antibody may be suitable for use in flow cytofluorimetric sorting of mixed populations of normal and tumour cells, allowing the investigation of cell phenotypes during hepatocarcinogenesis.
Augmentation of metastasis formation by thioglycollate‐elicited macrophages
Authors: Gorelik E. , Wiltrout R. H. , Brunda M. J. , Holden H. T. , Herberman R. B.
Published: February 2007

Inoculation of thioglycollate‐elicited peritoneal exudate cells (PEC) into C57BL/6 mice reduced the rate of lung clearance of several intravenously (i.v.) injected murine tumor cells, and increased by up to 100‐fold the number of artificially‐induced metastatic lung nodules produced by the i.v. injection of B16 melanoma or Lewis lung carcinoma (3LL) tumor cells. Maximum effects were observed when PEC were injected either before, or shortly after, tumor cells. Modulation of lung clearance or metastasis formation was observed only with PEC and not with a variety of other cells, such as splenocytes, thymocytes, P815 mastocytoma cells, or several macrophage‐like cell lines (PU5‐1.8 and IC‐21). Lysates of PEC were as efficient in reducing lung clearance and augmenting metastasis formation as were intact viable PEC. Lysates of other cell types, including P815 and the macrophage‐like cell lines, were unable to produce these effects. PEC populations, enriched for macrophages by adherence to plastic or by percoll density gradient sedimentation, also increased the number of B16‐induced artificial metastasis, implicating the macrophage as the cell responsible for these observations.
Tumorigenicity of human bk papovavirus plaque isolates, wild‐type and plaque morphology mutant, in hamsters
Authors: Watanabe Sumie , Kotake Setsuko , Nozawa Akemi , Uchida Seijiro , Muto Takeshi
Published: February 2007

The polyoncogenic prototype human papovavirus BKV (Gardner's strain) produced clear, small and large plaques. Two small‐plaque isolates (wt‐500 and wt‐502), as well as a large‐plaque‐forming isolate (wt‐501), induced frequent brain tumors and occasional osteosarcomas (but no insulinomas) in hamsters. The large‐plaque former (wt‐501) was more tumorigenic than the two small‐plaque isolates. One small (pm‐522) and one large turbid plaque mutant (pm‐525), which had been rescued from hamster tumor cell lines and have small deletion near the origin of DNA replication, induced frequent brain tumors and insulinomas. Mutant 522 was about five times more tumorigenic than wt‐501. These results support the hypothesis that the polyoncogenicity of prototype BKV is accounted for by the presence of BKV mutants.
Disease‐related lymphocyte cytotoxicity in rats bearing transitional cell carcinoma of bladder. effect of immunomodulators
Authors: Moroz Chaya , Madgar Igael , Twig Shoshana , Lindner Arie , Many Moshe
Published: February 2007

Blood lymphocytes from rats bearing transitional cell carcinoma (TCC) of the bladder were studied for their cytotoxicity in vitro against xenogeneic YAC‐1 target and against syngeneic TCC cells. Control lymphocytes were obtained from age and sex‐matched syngeneic rats. The following differences were observed: (I) lymphocytes from TCC‐bearing rats were cytotoxic to syngeneic TCC target cells whereas those from control rats were not; (2) lymphocytes from TCC‐bearing and control rats were cytotoxic to NK sensitive YAC‐I cells; however, NK cells from TCC‐bearing rats were more adherent to nylon wool‐columns than NK cells from control rats. The adherent and non‐adherent cells from TCC‐bearing rats were both cytotoxic to syngeneic TCC target cells. Levamisole treatment of effector cells from TCC‐bearing rats did not affect the NK activity, yet it increased the cytotoxicity of non‐adherent cells on TCC target cells. Treatment of the adherent cells with poly‐l:poly‐C increased slightly their NK activity on YAC‐I cells and their anti‐TCC cytotoxicity. However, a marked increase in the cytotoxicity by both adherent and non‐adherent cell fractions was observed on TCC target cells pretreated with poly‐l:poly‐C. A disease‐related cytotoxicity of lymphocytes from rats bearing TCC has been observed. Treatment of TCC target cells with poly‐l:poly‐C increased their susceptibility to lysis by the activated effector cells.
Suppressor macrophages in tumor‐bearing mice. Inconsistency between in vivo and in vitro findings?
Authors: Forni Guido , Giovarelli Mirella , Lanfrancone Luisa , Varesio Luigi
Published: February 2007

The growth of a spontaneous adenocarcinoma (ADK‐It) of BALB/c mice (H‐2d, Mlsb) induces progressive hyporesponsiveness of spleen cells stimulated with PHA or irradiated leukocytes from DBA/2 strain (H‐2d, Mlsa) in mixed leukocyte culture. This hyporesponsiveness is due to the suppressor activity of macrophage‐like cells, since it is abrogated by passage over nylon‐wool columns, pretreatment with carrageenans, or carbonyl iron and magnet. BALB/c mice bearing >20 mm mean diameter ADK‐It tumors, and displaying a drastic impairment of T lymphocyte reactivity in vitro, were challenged with the P815 mastocytoma of the DBA/2 strain. These mice rejected increasing numbers of P815 cells to the same extent as normal BALB/c mice. The reactivity towards P815 is abrogated by 450 rad, and can be reconstituted by the adoptive transfer of 2 × 107 normal T lymphocytes in either normal or ADK‐It bearing BALB/c mice. These data show that a discrepancy exists between the capacity of T lymphocytes from ADK‐It bearing mice to react against DBA/2 cells tested in vitro or in vivo, and indicates that great caution should be exercised in predicting the responsiveness of the immune system on the basis of in vitro data on the suppressor activity of macrophages.
Growth control and cell spreading: Differential response in preneoplastic and in metastatic cell variants
Authors: Raz Avraham , Ben‐Ze'ev Avri
Published: February 2007

Growth control and sensitivity to changes in cell shape were studied in anchorage‐dependent mouse fibroblasts (diploid fibroblasts, 3T3 and 3T6), in DNA tumor‐virustransformed mouse fibroblasts (SVPy 3T3), in four B16 melanoma and five uv‐2237 fibrosarcoma cell variants that exhibit distinct metastatic properties. Differential adhesive conditions were established by precoating the plastic plates with poly (2‐hydroxyethylmethacrylate) that allowed an accurate and reproducible control of cell shape, from flat to spherical. Mouse fibroblasts that form a continuum between rigorously controlled cells to fully anchorage‐independent cells, display a direct correlation between degree of growth control and sensitivity to changes in cell spreading. In contrast, there is no apparent direct correlation between sensitivity of growth control to changes in cellular configuration and the metastatic potential of tumor cells.
Interaction of Epstein‐Barr virus with leukaemic B cells in vitro. II. Cell line establishment from prolymphocytic leukaemia and from Waldenström's macroglobulinaemia
Authors: Finerty S. , Rickinson A. B. , Epstein M. A. , Platts‐Mills T. A. E.
Published: February 2007

Leukaemic B‐cell populations were prepared from six patients with high‐count prolymphocytic leukaemia (PLL) as well as from one patient with Waldenström's macroglobulinaemia (WM) in frankly leukaemic phase, and their response to in vitro Epstein‐Barr (EB) virus infection was monitored in terms of expression of the virus‐associated nuclear antigen EBNA and of virus‐induced transformation to continuous cell lines. The individual leukaemic populations, tested on several occasions, gave reproducibly different responses one from another which were not obviously related to differences either of surface immunoglobulin phenotype or of immunoglobulin secretor status in vivo. After infection, four out of six PLL populations showed either transient or a more persistent expression of EBNA, always involving a minority of the cells, with no evidence of any virus‐induced transformation up to six weeks. In contrast, two out of six PLL samples as well as the WM sample rapidly gave rise to EBNA‐positive cell lines which, on the evidence both of restricted immunoglobulin class expression and of abnormal marker chromosomes, were clearly derived from the leukaemic cells. Further comparative studies of such leukaemic B‐cell populations may help to define host cell components necessary for the triggering of EB‐virus‐induced cellular transformation.
Expression on cultured human tumour cells of placental trophoblast membrane antigens and placental alkaline phosphatase defined by monoclonal antibodies
Authors: McLaughlin P. J. , Cheng M. H. , Slade M. B. , Johnson P. M.
Published: February 2007

The cellular reactivity of six monoclonal antibodies (McAbs) produced to isolated human placental syncytiotrophoblast microvillous plasma membranes has been examined using a variety of normal and malignant cell types. Two McAbs reacted with antigenic determinants common to most normal human cells. Two other McAbs (H310 and H316) reacted predominantly with normal placental trophoblast and with lymphocytic cells, as well as with most transformed or neoplastic cultured cell lines. Two further McAbs (H315 and H317) identified foetal differentiation antigens expressed only on the membranes of normal placental trophoblast and of certain tumor cell lines. H317 has been shown to be specific for the heatstable L‐phenylalanine‐inhibitable placental‐type alkaline phosphatase isoenzyme. These latter McAbs (H315 and H317) may prove useful in monitoring of some human cancers.
Chromosomes of human hepatoma cell lines
Authors: Simon Daniela , Aden David P. , Knowles Barbara B.
Published: February 2007

The karyotypes of three human hepatoma cell lines Hep G2, Hep 3B and PLC/PRF/5 were investigated by G‐ and C‐banding techniques. In addition to ploidy changes, typical for most carcinoma cell lines, certain markers were found that remained stable throughout passage of these cultures. Chromosome I is involved in multiple translocations, resulting in at least three copies of the chromosome I heterochromatin region in each cell line. Inversion in the 9qh region is also seen. In addition, each of the cell lines consistently contains trisomy of 17q. The rearrangements of chromosome I are most striking in the Hep 3B and PLC/PRF/5 cell lines, which are derived from human hepatocellular carcinomas and contain integrated copies of the hepatitis B viral genome. These two cell lines are characterized by the presence of at least five copies of the I (p13←q21) region that result from multiple deletions and/or translocations; by consistent trisomy and polymorphism of the 9qh region; and by trisomy of chromosome 10 (also involved in rearrangements). The Hep G2 and Hep 38 cell lines behave functionally as highly differentiated liver parenchymal cells and are karyologically distinguishable from PLC/PRF/5 both by the presence of trisomy of 6 (pter←q14) and by the finding that one of the homologues of chromosome 15 is 15q+.
Immunochemical demonstration of an ovarian cancer‐associated urinary peptide
Authors: Stenman Ulf‐Håkan , Huhtala Marja‐Liisa , Koistinen Riitta , Seppälä Markku
Published: February 2007

Immunization with a peptide fraction from ovarian cancer urine resulted in an antiserum that reacts with a 6,000‐dalton (6K) peptide. In urine from some patients with advanced gynaecological cancer, the concentration of 6K peptide was high enough to be detected by immunodiffusion. By radioimmunoassay the levels in normal serum could be determined. The concentration in serum was 5–20 μg/1 and that in urine 5–50 μg/1. Elevated levels were observed in urine from 5 out of 8 patients with ovarian cancer, 10 out of 14 patients with cervical cancer and 9 out of 14 patients with endometrial cancer. The highest level observed was 12,000 μg/1. High concentrations of the 6K peptide (100–300 μg/1) were observed in amniotic fluid from 14–16 weeks of pregnancy. Some tumor extracts also had a high concentration of the 6K peptide. No immunological relationship was observed between the peptide and known tumor‐associated antigens or serum proteins. These results suggest that the peptide is a new oncodevelopmental peptide which may have significance as a tumor marker.
Direct cytolysis by partially‐purified preparations of immune interferon
Authors: Tyring Stephen , Klimpel Gary R. , Fleischmann W. Robert , Baron Samuel
Published: February 2007

Mouse IFNγ preparations purified 30‐fold were found to have direct cytolytic activity against a number of tumor and normal cells. Cell killing was determined using a sensitive, rapid and accurate assay which employed very low numbers of cells and very small quantities of interferon. The cytolytic activity of IFNγ on 11 murine tumor cell lines was investigated. A 20‐fold difference was found between the most sensitive cell type, P‐388 lymphoma, versus the most resistant cell type, C127v leukemia. A number of normal mouse cells was also found to have low to intermediate sensitivity to the cytolytic action of IFNγ. Human IFNγ was also shown to have cytolytic activity which, like mouse IFNγ, was relatively species‐specific. Direct cytolysis was not found to be a characteristic of IFN‐α/β. Different mechanisms of action for the antiviral and cytolytic activities of IFNγ are indicated because the cytolytic titer of IFNγ did not parallel its antiviral titer on most cell types and increasing the cell number produced a decrease in the cytolytic titer and an increase in the antiviral titer. High concentrations of IFNγ (i.e., 2,900 units/ml) resulted in complete lysis of cells within 24 h, while lower concentrations (i.e., 700 units/ml) resulted in a reversible inhibition of cell growth during this time period. Evidence that the cytolytic substance in the IFNγ preparation was IFNγ include the following: (1) both antiviral and anticellular activities copurified through a 30‐fold purification; and both activities were (2) relatively speciesspecific; (3) sensitive to heat; (4) inactivated by low pH and (5) neutralized by antibodies to IFNγ. Therefore, we propose the possibility that direct cytolysis is yet another of IFNγ's distinctive antivities.
Identification of the RPMI 8226 retrovirus and its dissemination as a significant contaminant of some widely used human and marmoset cell lines
Authors: Popovič M. , Kalyanaraman V. S. , Reitz M. S. , Sarngadharan M. G.
Published: February 2007

A retrovirus designated RPMI 8226V, isolated in 1973 from the human myeloma cell line RPMI 8226 has been characterized by competition radioimmunoassay (RIA) for the major viral structural protein and by nucleic acid hybridization analysis using cDNA of the virus. The virus is highly related to the squirrel monkey type D retrovirus, SMRV. In the homologous RIA using rabbit anti‐RPMI 8226V and 125I‐labelled p36 of RPMI 8226V, RPMI 8226V and SMRV exhibited competition of 81% and 73% respectively. Similarly, in the homologous system for SMRV p36, these viruses competed 98 and 100%. Reagents made from the type D retrovirus, Mason Pfizer Monkey Virus (MPMV), known to be related but distinct from SMRV, were used in assays designed to detect interspecies determinants of type D retroviruses. In assays using goat anti‐MPMVp26 vs SMRV 125I‐p36, RPMI 8226V, SMRV and MPMV competed to the same extent (93%). Hybridization analysis of RPMI 8226V cDNA showed significant homology to cellular RNA and DNA of mink, bat, and human cells infected with RPMI 8226V and to DNA of SMRV infected cells but not to uninfected cells or cells infected with other viruses. These results taken together clearly indicate that RPMI 8226V and SMRV are very closely related to each other. The finding of a type D retrovirus in this human myeloma cell line that had been used in EBV studies (the usual source of EBV being the marmoset cell line B95‐8) prompted a survey of RPMI 8226V in some human and marmoset cell lines. The assays included the RIA for p36, nucleic acid hybridization using cDNA of RPMI 8226V, reverse transcriptase analysis, and electronmicroscopy (EM). The results clearly show that in addition to RPMI 8226, human Burkitt lymphoma cells BJAB/B‐95‐8/K which were supertransformed by EBV from B‐95‐8/K marmoset cells as well as marmoset cell lines [(B‐95‐8/K and B‐95‐8/N) obtained from Stockholm and Uppsala, Sweden] were positive for the RPMI 8226V. Similar lines obtained elsewhere were negative. The results obtained clearly indicate that RPMI 8226V is a serious laboratory contamination in some widely used human cell lines. The possible impact of this viral contamination for some virological and cell biological studies is discussed.
Mammary tumor induction in inbred mouse strains with urethane is not accompanied by changes in expression of B‐ and C‐type retroviral structural proteins
Authors: Imai Shunsuke , Morimoto Junji , Tsubura Yoshihiko , Hilgers Jo
Published: February 2007

Urethane administrated in the drinking water of breeding female mice of five inbred strains (DDf, KF, C3Hf, ddY and C57BL) leads to a higher incidence of mammary tumors at an extremely early age in four of these strains (DDf, KF, C3Hf and ddY). In the case of the DDf strain the tumors are adenoacanthomas, but in the case of the other strains adenocarcinomas are also observed. The effect of urethane in the drinking water on expression of endogenous retroviral structural proteins of the B and C type (MTV and MuLV) was studied in the milk by an immunodiffusion test and in organ extracts by radioimmunoassays (for MTVp27, MTVgp52 and MuLVp30). Organs tested include salivary glands, thymus and spleen from female and male animals. In addition, prostate and seminal vesicles were tested in male animals and uterus and mammary glands in females. Mammary tumors induced by urethane were also tested. Urethane does not induce or enhance endogenous retroviral antigen expression, either in these organs or in the mammary gland, one of the target organs for tumorigenesis by this agent.
Vitamin A levels in human bladder cancer
Authors: Mahmoud Lotfy Abdel Naby , Robinson William A.
Published: February 2007

The following studies were undertaken to determine the levels of serum carotene and vitamin A (retinol) in Egyptian patients with intestinal, urinary, hepatosplenic schistosomiasis, and bladder cancer. These studies have shown that both serum carotene and serum retinol levels are significantly reduced in patients with bladder cancer when compared to controls. These data, when viewed in light of previous animal studies noted, raise the question as to whether vitamin A administration can be beneficial in the prevention and/or treatment of human bladder cancer, particularly that associated with schistosomiasis.
Neoplastic transformation of human cells in culture associated with deficient repair of light‐induced chromosomal DNA damage
Authors: Parshad Ram , Sanford Katherine K. , Jones Gary M. , Tarone Robert E.
Published: February 2007

Two lines of normal human skin fibroblasts and five derivative lines transformed in culture to neoplastic cells by chemical carcinogens were compared with respect to chromatid breakage produced by exposure to low‐intensity fluorescent light (cool‐white, 4.6 W/m2) during pre‐S, S, and late S‐G2 periods of the cell cycle. Five additional normal human cell lines and a line derived from a lung adenocarcinoma were also examined for chromatid damage following light exposure during pre‐S and late S‐G2. On the assumption that each chromatid (half chromosome) contains a single continuous DNA double helix, chromatid breaks seen in the first post‐treatment metaphase must represent unrepaired DNA doublestrand breaks. The frequency of chromatid breaks induced by pre‐S light exposure in the neoplastic cell is not significantly different from that in the normal cells. However, addition of caffeine, an inhibitor of DNA repair, to the culture medium following light exposure significantly increases the frequency of chromatid breaks in the neoplastic but not in the normal cells. One possible explanation for these observations is that the normal cells, known to have effective excision repair, remove the DNA damage, whereas the neoplastic cells, presumably deficient in excision repair, handle the damage during S by a caffeinesensitive mechanism. Furthermore, the neoplastic but not the normal cells, show significant increases in chromatid breaks when exposed during S or late S‐G2The chromatid damage produced by late S‐G2 exposure can be completely prevented by addition of mannitol, a scavenger of free hydroxyl radicals. Addition of caffeine to the culture medium during late S‐G2 light exposure has no effect on the frequency of chromatid breaks in the neoplastic cells but signincantly increases chromatid breakage in the normal cells. These results suggest that the normal cells repair the late S‐G2 light‐induced damage by a caffeine‐sensitive repair mechanism that is absent or deficient in the neoplastic cells. It thus appears that neoplastic cells are deficient in mechanisms for repair of DNA damage induced by light both during pre‐S and late S‐G2periods of the cell cycle.
Interferon and natural killer activity in multiple myeloma. Lack of correlation between interferon‐induced enhancement of natural killer activity and clinical response to human interferon‐α
Authors: Einhorn Stefan , Ahre Anders , Blomgren Henric , Johansson Bo , Mellstedt Håkan , Strander Hans
Published: February 2007

Natural killer (NK) activity of peripheral lymphocytes was measured in 39 patients with multiple myeloma prior to and during interferon (IFN) therapy. NK activity increased in a majority of patients following the first injection of IFN and remained at an increased level during I year of therapy. Lower doses of IFN seemed to induce a greater increase in NK activity than higher doses. No correlations could be observed between the response of the tumors to IFN therapy and pretreatment levels of NK activity, IFN‐induced enhancement of NK activity in vitro or IFN‐induced enhancement of NK activity in vivo.
Acquisition of tolerance to the antiproliferative activity of interferon by X‐ray transformed C3H/10T1/2 cells under prolonged treatment with interferon
Authors: Brouty‐Boyé Danièle
Published: February 2007

X‐ray‐transformed C3H/10T1/2 cells serially passaged in the presence of highly purified mouse interferon appeared to acquire progressively a tolerance to the inhibitory effect of interferon on cell proliferation. In contrast, these cells did not appear to develop a tolerance to the antiviral activity of interferon. These results suggest the possibility that these two effects of interferon are mediated by different mechanisms.
Translocation t(8;22) in peripheral lymphocytes and established lymphoid cell lines from a patient with Hodgkin's disease followed by acute lymphatic leukemia
Authors: Fonatsch Christa , Burrichter Heinz , Schaadt Michael , Kirchner Hartmut H. , Diehl Volker
Published: February 2007

Cytogenetic studies on primary material and established cell lines of a patient with B‐cell non‐Hodgkin Lymphoma with leukemic presentation as secondary malignancy after Hodgkin's disease clearly revealed correspondent marker chromosomes in both culture systems. A translocation t(8;22) which has been described in some cases of non‐endemic Burkitt's lymphoma as a variant of the translocation t(8;14) was found in all metaphases of the cell lines and in most of the cells of the primary material. In addition, structural aberrations involving chromosomes 1, 2, 3 and 11, as well as numerical deviations concerning chromosomes 2, 4, 7 and Y, could be observed. The cytogenetical findings are discussed in relation to clinical, immunological and cytochemical data.
Variation in selectivity of tumor cell cytolysis by murine macrophages, macrophage‐like cell lines and NK cells
Authors: Wiltrout Robert H. , Brunda Michael J. , Holden Howard T.
Published: February 2007

Several murine tumor‐cell lines were tested by isotope release assays for their susceptibility to lysis by either activated peritoneal macrophages (apMPh), macrophage‐like (MPh‐like) cell lines, or natural killer (NK) cells. The qualitative selectivity of tumor‐cell lysis by these different effector cells was quite disparate. The rank order of target cell susceptibility to lysis by apMPh in 24 h assay was L5178Y > P815 ≌ RL♂ > YAC‐1 ≌ MBL‐2. This was seen regardless of whether peritoneal MPh (pMPh) were activated by LPS or poly I:C. Two MPh‐like cell lines, PU‐5R and FC‐1, had a pattern of cytotoxic activity against these target cells that closely paralleled that associated with apMPh, although levels of reactivity differed quantitatively among the effector cells. In contrast, the MPh‐like cell line RAW‐264 expressed a qualitatively different pattern of target‐cell selectivity, preferentially lysing MBL‐2, which was relatively refractory to lysis by other MPh‐like cell likes or apMPh in the 24 h cytolytic assay. When spontaneous or interferon (IFN)‐augmented NK activity was measured against the same panel of target cells, the pattern of selectivity was qualitatively different from that observed for apMPh. The consistent rank order of susceptibility to lysis by NK cells was YAC‐1 > RL♂1 > P815 ≌ L5178Y ≌ MBL‐2. The characteristic patterns of target‐cell selectivity for apMPh or NK cells were the same for all of the strains of mice tested. From the different selectivity patterns of apMPh and NK cells, it is concluded that lysis of target cells is not based solely on inherent sensitivity to cytolysis. Instead, selectivity of lysis is probably due to variations in expression of target‐cell structure recognized by each type of effector cell, and/or in susceptibility to the lytic mechanism(s) of the various effector populations.
High‐ and low‐leukemogenic variants of the radiation leukemia virus (RadLV) differ in ability to induce tumor‐specific immune suppression
Authors: Yefenof Eitan , Zilcha David
Published: February 2007

Adult C57BL/6 mice inoculated intrathymically (i.t.) with the highly leukemogenic variant of the radiation leukemia virus (A‐RadLV) develop suppressor cells capable of specifically abrogating a potential anti‐tumor cytotoxic response in vitro. Suppressor cells were generated directly by the virus, independently of an initiation of a leukemogenic process. Inoculation of C57BL/6 animals with the low leukemogenic D‐RadLV variant did not result in suppressor cell generation. It is proposed that induction of tumor‐specific immune suppression by A‐RadLV is essential for tumor progression, and the leukemogenic activity of D‐RadLV is attributed to its inability to recruit suppressor cells.
Combinational chemotherapy of L1210 and L1210/ARA‐C leukemia with 5‐AZA‐2′‐deoxycytidine and β‐2′‐deoxythioguanosine
Authors: Momparler Richard L. , Momparler Louise F. , Samson Johanne
Published: February 2007

The in vitro and in vivo antineoplastic activity of 5‐AZA‐2'‐deoxycytidine (5‐AZA‐CdR) and β‐2‐deoxythioguanosine (TGdR) on L1210 an L1210/ARA‐C (resistant to cytosine arabinoside) leukemic cells was investigated. 5‐AZA‐CdR was a very potent cytotoxic agent against the L1210 leukemic cells. This analogue was inactive against L1210/ARA‐C leukemic cells because these cells lack deoxycytidine kinase, the enzyme that converts 5‐AZA‐CdR to its active nucleotide form. TGdR was a potent cytotoxic agent to both L1210 and L1210/ARA‐C leukemic cells. In mice which were injected simultaneously with both L1210 and L1210/ARA‐C leukemic cells, the drug combination of 5‐AZA‐CdR plus TGdR had a very potent antineoplastic activity and producet long‐term survivors. Either agent alone did not produce any long‐term survivors in the mice with L1210 and L1210/ARA‐C leukemia. This experimental model indicates that 5‐AZA‐CdR plus TGdR is an interesting drug combination for the treatment of leukemia with drug‐resistant cells.
Neoplastic transformation of rabbit cells by murine sarcoma viruses
Authors: Rhim J. S. , Bedigian H. G. , Fox R. R.
Published: February 2007

Neoplastic transformation of rabbit cells by Kirsten murine sarcoma virus (Ki‐MSV), the Ki‐MSV pseudotype of baboon endogenous virus (Ki‐MSV[BaEV]) and the Moloney‐MSV pseudotype of feline leukemia virus (M‐MSV[FeLV]) is reported. Rabbit cells can be readily transformed by Ki‐MSV, Ki‐MSV(BaEV) and M‐MSV(FeLV). Rabbit cells transformed by Ki‐MSV and M‐MSV(FeLV) were found to be virus producers, whereas those transformed by Ki‐MSV(BaEV) were nonproducers (NP). The NP cells were obtained by simply infection rabbit cells with Ki‐MSV(BaEV) and subculturing the infected cells. Although the morphologically altered NP cells did not produce infectious virus or murine leukemia virus antigen, they did contain a rescuable MSV genome. All of the transformed cells formed colonies in soft agar, grew to high saturation densities and produced tumors when transplanted into nude mice. The Ki‐MSV and M‐MSV(FeLV)‐transformed cells produced tumors in newborn WH/J rabbits, thus providing an important tool for studying tumor immunity in the rabbit.
Environmental and genetic factors determine the level of NK activity of nude mice and affect their suitability as models for experimental metastasis
Authors: Hanna N. , Davis T. W. , Fidler I. J.
Published: February 2007

In these studies we have evaluated the effects of age, genetic background, and housing conditions on the NK‐cell activity of nude mice measured in vitro and resistance to tumor metastasis in vivo. BALB/cAnN nude mice exhibited lower levels of NK‐cell‐mediated cytotoxicity than age‐matched N:NIH(S) nude mice maintained under similar housing conditions. The stronger response of N:NIH(S) nude mice was observed also after experimental activation of NK cells by Corynebacterium parvum. Nude mice maintained under barrier conditions have weaker NK‐cell activity than mice maintained under conventional conditions. The incidence of experimental pulmonary metastases of allogeneic tumors injected into nude mice was inversely correlated with the levels of NK‐cell‐mediated cytotoxicity. Thus, 3‐week‐old BALB/cAnN nude mice raised under barrier conditions were more sensitive to development of experimental metastasis than age‐matched N:NIH(S) nude mice maintained under barrier conditions or nude mice of either strain maintained under conventional conditions. In both strains, however, the relative differences in metastatic potential among the tumor cell lines observed in syngeneic recipients were maintained. We conclude that young BALB/cAnN nude mice raised under barrier conditions may provide a valuable in vivo model for studying metastasis of neoplasms.
Epstein‐Barr virus strain‐specific differences in transformed cell lines demonstrated in growth characteristics, induction of viral antigens and ADCC susceptibility
Authors: Sairenji Takeshi , Jones Wendy , Spiro Robert C. , Reisert Patricia S. , Humphreys Robert E.
Published: February 2007

Paired lymphoid cell lines were established by transformation with both B95‐8 (B) and QIMR‐WIL (Q) EBV strains, of cells either from cord blood or from peripheral blood or spleens of patients with leukemias or lymphomas. The morphologies of the transformed cell clumps differed consistently between B‐transformed lines (B‐lines) and Q‐transformed lines (Q‐lines) even after 1 year in culture. When the B‐ and Q‐lines were compared for superinfection with P3HR‐1 EBV, B‐lines had a higher frequency of EA induction than did the Q‐lines. The shape of dose‐response curves for superinfection indicated that a much higher multiplicity of infection by P3HR‐1 EBV was required for EA expression in Q‐lines than in B‐lines. This difference in superinfection was independent of the EBV receptor concentration on the two types of lines and reflected apparent control of the level of EA induction by the resident EBV genome of the transformed line. Transforming EBV could be rescued by P3HR‐1 EBV superinfection of both B‐ and Q‐lines originating from cells of patients with Hodgkin's disease and hairy cell leukemia but not from cord blood. The cord blood lines transformed with virus produced spontaneously from these B‐ or Q‐lines, showed that the cell lines contained antigen‐determining information of the resident genome in the original B‐ or Q‐lines, respectively. Superinfected B‐lines were more susceptible to ADCC with anti‐EBV‐positive sera than were superinfected Q‐lines. These experiments demonstrate that distinct biology. differences exist in paired cell lines transformed by different EBV strains.
Human melanoma cells can be killed in vitro by an immunotoxin specific for melanoma‐associated antigen p97
Authors: Casellas P. , Brown J. P. , Gros O. , Gros P. , Hellström I. , Jansen F. K. , Poncelet P. , Roncucci R. , Vidal H. , Hellstrom K. E.
Published: February 2007

Conjugates (immunotoxins) comprising ricin A‐chain and monoclonal antibody 96.5, which is specific for human melanoma‐associated antigen p97, inhibited protein synthesis and colony formation of cultured human melanoma cells that expressed more than 80,000 molecules of p97 per cell. Cells expressing fewer than 5,000 molecules of p97 were not killed. The presence of 10 mM ammonium chloride significantly increased the efficiency of the immunotoxin, tumor cells expressing high levels of p97 being killed at immunotoxin concentrations as low as 10−10 M.
Natural cytotoxic cells against solid tumors in mice. IV. Natural cytotoxic (NC) cells are not activated natural killer (NK) cells
Authors: Lattime Edmund C. , Pecoraro Gene , Stutman Osias
Published: February 2007

Natural cell‐mediated cytotoxicity (NCMC), measured against a variety of tumors, is mediated by at least two sub‐populations of effector cells: natural cytotoxic (NC) and natural killer (NK). The studies described in this report show that target lysis by NC cells requires a prolonged (18‐ to 24 h) assay period, whereas NC‐susceptible targets can be lysed in short‐term (4 h) [3H]‐proline assays using allo‐sensitized CTL or mitogen‐activated cytotoxic populations. NC cells are not “activated” during the long‐term assay as indicated by: (1) demonstrating that lysis of NC‐susceptible targets in long‐term (20 h) 51Cr assays is still the function of a Qa‐5 effector cell (NC) and (2) the fact that preincubation of the NC effector cell with susceptible targets for 18 h did not result in the activation of an NK‐like population (kinetics of target lysis were comparable to those noted with fresh NC cell preparations). We show that NC cell activity is preserved in both the beige mutant and the PL/J mouse strains, both of which exhibit low NK cell activity, even in long‐term assays. These combined studies support the view that NC and NK cell activities are the function of distinct cell types and not the property of a single cell class under different states of activation.
Discordant Epstein‐Barr virus nuclear antigen (EBNA) antibody patterns in nasopharyngeal carcinoma
Authors: Hewetson John F. , Levine Paul H. , Neubauer Russell H. , Rabin Harvey
Published: February 2007

Epstein‐Barr virus nuclear antigen (EBNA) preparations from three sources were tested with sera from normal individuals and patients with Hodgkin's disease, breast carcinoma, Burkitt's lymphoma, and American and Chinese nasopharyngeal carcinoma. Individual sera with discordant antibody patterns were noted in all groups. Sera from both NPC groups gave significantly higher anti‐EBNA titers on cell lines converted with P3HR‐1 or B95‐8 virus compared with anti‐EBNA titers on Raji cells. Anti‐EBNA titers of Chinese NPC sera showed no correlation among the three EBNA sources, while all other groups had highly correlated titers. Cross‐absorption experiments present evidence for more than one antigenic determinant on EBNA. These results suggest an additional parameter for distinguishing Chinese NPC from other EBV‐related disorders.
Effect of interleukin 2 on cytotoxic effectors: I. short‐term culture of the cytotoxic effectors and the in vivo anti‐tumor activity of the cultured effectors isolated from tumor site
Authors: Ting Chou‐Chik , Yang Stringner S.
Published: February 2007

The effects of interleukin 2 (IL2) on the in vitro and in vivo activity of cytotoxic T cells have been studied. IL2 was produced by W/Fu rat spleen cells cultured with concanavalin A. The IL2 thus prepared gave an optimal T‐cell growth‐promoting effect at a concentration of 5–20% equivalents of the original preparation. In the primary, syngeneic mixed lymphocyte/tumor cell cultures (MLTC) against FBL‐3 tumor cells, the addition of IL2 failed to generate a cytotoxic response. However, the cytotoxic response could be generated in MLTC by addition of exogenous macrophages. On the other hand, IL2 could maintain the growth of preformed cytotoxic T cells for 3 to 5 weeks. These cytotoxic T cells were generated either by in vitro sensitization (MLC or MLTC) or by in vivo sensitization of B6 mice against a syngeneic tumor FBL‐3. In short‐term cultures, augmentation of the cytotoxic activity was seen after 10 days' culturing with IL2. The antigenic specificity of the cytotoxic reaction was altered after 28–35 days in culture, and the effectors broadly reactive. When growing a nonadherent population of lymphocytes isolated from FBL‐3 ascites tumor, supplementation with IL2 selectively promoted the growth of a T‐cell population, resulting in the elimination of the contaminating tumor cells. These purified T cells were highly cytotoxic for FBL‐3 cells in vitro and also possessed strong in vivo anti‐tumor activity against FBL‐3 cells in the adoptive transfer experiments. The present study demonstrates that short‐term culture (2–3 weeks) in IL2 promotes the growth of T cells and augments their cytotoxic activity with the appropriate antigenic specificity. IL2 also promoted the selective growth of T cells isolated from tumor site and these T cells showed augmented in vitro and in vivo anti‐tumor activity.
Cytogenetic changes during tumor progression towards invasion, metastasis and immune escape in the Eb/ESb model system
Authors: Dzarlieva R. , Schirrmacher V. , Fusenig N. F.
Published: February 2007

Related tumor lines which represent different stages in their progression towards metastatic capacity were investigated and compared at the chromosomal level. The parental low‐metastatic tumor line (L5178Y/Eb) was derived from a long‐term transplanted, chemically induced T‐cell lymphoma of the DBA/2 mouse. The cytogenetic analysis included this Eb line, a spontaneous high metastatic variant thereof which expressed a distinct tumor‐associated transplantation antigen (ESb TATA+), and an immunoresistant TATA‐negative variant of the latter (ESb TATA−). All three cell lines were characterized by a near‐diploid chromosome count and by some common chromosomal markers derived from Nos. 6, 13 and 16 Large‐scale chromosomal rearrangments resulted in the formation of eight marker chromosomes in Eb cells, 16 in ESb TATA+ cells and 18 in ESb TATA− cells. Tumor progression in this system showed a tendency to monosomies, which could bring the corresponding genes to a hemizygous state and possibly to a release from repression. Chromosome 15 was trisomic in Eb cells, monosomic in ESb TATA+ cells and hardly detectable in ESb TATA− cells. The Ig heavy‐chain gene‐carrying region of both chromosomes No. 12 was found in translocation with chromosomes Nos. 5, 13 and 14 (Eb cells) and with Nos. 1 and 17 (ESb cells). ESb TATA− cells differed from ESb TATA+ cells at four different chromosomes (Nos. 5, 8, 14 and 15).
Adenovirus‐12 genes undetectable in human retinoblastoma
Authors: Mak S. , Mak I. , Gallie B. L. , Godbout R. , Phillips R. A.
Published: February 2007

Retinoblastoma is a rare eye tumor found predominantly in young children. Intra‐ocular injection of adenovirus‐12 (Ad‐12) into newborn recipients induces in rats and in baboons tumors morphologically similar to human retinoblastoma tumors. In addition, Ad‐12 DNA can transform human embryonic retinal cells and the transformed cells form retinoblastoma‐like tumors in nude mice. These observations have led to the suggestion that Ad‐12 may also be involved in the induction of human retinoblastoma tumors. To test this possibility, DNA and RNA were isolated from six human tumors. Analysis of RNA and DNA by blotting with labelled Ad‐12 failed to reveal viral sequences in human retinoblastoma.
Histologic features of bladder cancer in Boston, USA, Manchester, UK, and Nagoya, Japan
Authors: Morrison Alan S. , Proppe Karl H. , Verhoek Wendy G. , Aoki Kunio , Leck Ian , Ohno Yoshiyuki , Obata Koji
Published: February 2007

Histologic characteristics of bladder cancer in Boston, USA, Manchester, UK, and Nagoya, Japan, were evaluated. In each of these areas broadly‐based series of cases were assembled during a collaborative case‐control study. The present analysis was based on 589 cases in Boston, 484 cases in Manchester, and 241 cases in Nagoya. A single pathologist reviewed a slide of the primary tumor without reference to identifying information or other data. The primary histologic type of nearly all tumors was transitional‐cell, and there was little variation in the proportion of transitional‐cell tumors among the study areas. Nor was there much variation in the distribution of histologic grade, the proportion of tumors showing submucosal invasion, or the proportion of tumors with a papillary surface. Age at diagnosis was strongly correlated with histologic grade. The proportion of grade III (most malignant) tumors was about twice as high among patients 80 years of age and over as among those aged less than 50. An apparent association between age and submucosal invasion was explained in large part by the relationships of histologic grade to submucosal invasion and to age. Other histologic features had only weak and inconsistent relations with age. None of the features evaluated showed consistent associations with history of cigarettesmoking or with sex.
Cloning of human solid tumors in soft agar
Authors: Kern David H. , Campbell Mary Ann , Cochran Alistair J. , Burk Martyn W. , Morton Donald L.
Published: February 2007

Of 1,014 human solid tumors of various histologic types, 690 (68%) showed evidence of colony formation within 2 to 4 weeks. Tumors which grew particularly well were colon carcinoma (104/175), melanoma (134/155), lung carcinoma (62/85), breast cancer (100/140), ovarian carcinoma (50/67), and sarcoma (72/122). Histologic examination indicated that the colony‐forming cells retained functional and morphologic features similar to those of the original tumor. Plating efficiencies varied between 0.01% and 0.2%, and the numbers of colonies observed formed a direct linear correlation with the number of cells plated. Recovery of viable tumor cells was increased when enzymatic tumor dissociation was used rather than a mechanical method. A simplified, supplemented medium resulted in improved cloning efficiencies when compared to previously reported methods (Hamburger and Salmon, 1977 b).
Effect of epidermal growth factor on clonogenic growth of primary human tumor cells
Authors: Pathak Meera A. , Matrisian Lynn M. , Magun Bruce E. , Salmon Sydney E.
Published: February 2007

The effect of EGF on the soft agar colony‐forming ability of fresh human tumor cells was assessed in 40 specimens obtained from various types of carcinoma including those of the breast, endometrium, ovary, and other sites. Cells from four established human tumor cell lines (three breast and one endometrial) were also included in this study. The results showed that addition of EGF at a concentration of 50 ng/ml resulted in a 50% higher cloning efficiency in soft agar in 40% of the samples of fresh human tumors. When cells from tumor cell lines were plated in semi‐solid medium containing EGF, the number of colonies formed was at least twice as high as controls. Cells from fresh tumor biopsies were assayed for EGF receptors to determine whether the correlation between the proliferative response in EGF‐supplemented semi‐solid medium as compared to control could be related to the number of EGF receptors present on the cells. Specific receptors for EGF were detected by using radioiodinated EGF in early‐passage cell cultures from some of the tumors tested for clonogenicity. The number of receptors ranged from 0.3 to 3.27 × 105 per cell. Cells from two melanoma specimens possessed less than 0.3 × 103 EGF receptors per cell. We found no correlation between the number of EGF receptor on a cell surface and the mitogenic effect of EGF on the same tumor cells grown in semi‐solid medium.
Autoinduction of differentiation in wehi‐3B leukemia cells
Authors: Metcalf Donald , Nicola Nicos A.
Published: February 2007

Cells of the differentiation‐responsive mouse myelomonocytic leukemia cell line WEHI‐3B D+ form colonies in agar exhibiting a low frequency of spontaneous differentiation mainly in the macrophage pathway. Compared with undifferentiated colonies, spontaneously differentiating colonies have a reduced content of clonogenic cells and surviving clonogenic cells tend themselves to form differentiating colonies, both being characteristics of differentiated colonies induced by the regulator, granulocyte colony‐stimulating factor, G‐CSF. Colony crowding increased the frequency of spontaneously differentiating colonies and WEHI‐3B D+ colony cells were shown to release material able to induce differentiation in WEHI‐3B D+ colonies. Cells from spontaneously differentiating D+ colonies were not hyperresponsive to the induction of differentiation by G‐CSF and did not release larger amounts of differentiation‐inducing material than did cells from undifferentiated colonies. Cells of the differentiation‐unresponsive WEHI‐3B D− line produced similar amounts of differentiation‐inducing material to those produced by D+ cells. Apparently spontaneous differentiation in WEHI‐3B D+ colonies seems most likely to be due to exposure of the colony‐forming cell or its ancestors to a differentiation‐inducing factor of WEHI‐3B origin prior to culture in agar, the genetic program initiating differentiation being inherited by the progeny of the exposed cell.