bluuebunny/crossref_metadata_2025_split huggingface dataset:
Internalization and intracellular processing of an anti B‐cell lymphoma monoclonal antibody, ll2
Authors: Shih Lisa B. , Lu Helen H.‐Z. , Xuan Hong , Goldenberg David M. 
Published: February 2007

AbstractThe successful clinical experience with antibody LL2 (an IgG2a, anti‐B‐cell lymphoma antibody) in radipimmunodetection and radioimmunotherapy suggests that this antibody may have potential as a carrier of cytotoxic agents. The internalization, cellular trafficking, and catabolism of this antibody in target human Burkitt lymphoma cells (Raji) were investigated. Internalization of intact antibody as well as of the F(ab')2 and Fab' fragments was detected by an FITC‐labeled anti‐mouse second antibody probe, and evaluated by fluorescence microscopy. Internalization of intact IgG (or the fragments) was observed as early as 5 min after incubation at 37°C. Initially, the internalized antibodies were present as micro‐particles inside the cell membrane, and were translocated to the lysosomal compartment within 2 hr. The anatomic location of the internalized antibody, before translocation to the lysosomal compartment, was deduced by comparing the fluorescence images obtained with the antibody to those obtained with fluorescent probes with known cellular distribution in a co‐internalization study. A Golgi‐like compartment was found to be involved in the translocation of the antibody. Cellular catabolism of the bound antibody was studied by using 125I‐labeled antibody on the target cells. At 21 h, 40% of the radioactivity was released into the supernatant as degraded fragments. The observation suggested that the antibody was degraded mainly in the lysosomes, since the degradation was significantly inhibited in the presence of lysosomal inhibitors such as ammonium chloride or leupeptin. Subcellular fractionation of Raji cells after the binding of 125I‐lbeled LL2 indicated that the antibody was translocated to lysosomes as evidenced by SDS‐PAGE. The rate of internalization (K) of LL2, and the re‐expression of the antigen were determined. The rapid Internalization of LL2 and the reexpression of the antigen suggest that this antibody may have potential as a therapeutic immunoconjugate, since it could deliver a higher accumulation of cytotoxic agents into lymphoma cells.
The scid mouse environment causes immunophenotypic changes in human immature T‐cell lines
Authors: Uittenbogaart Christel H. , Anisman Deborah J. , Tary‐Lehmann Magdalena , Vollger Leanne W. , Breit Timo M. , van Dongen Jacques J. M. , Saxon Andrew 
Published: February 2007

AbstractIn order to evaluate whether the SCID mouse can provide the microenvironment for the growth of human immature T‐cell leukemias and if in vivo growth alters their phenotype, we examined the behavior of 3 well‐characterized T‐cell acute lymphoblastic leukemia (T‐ALL)‐derived T‐cell lines which are at different stages of maturation (CEM, SUP‐T3 and MOLT‐4f) after transfer to non‐irradiated SCID mice. All 3 T‐cell lines engrafted and proliferated to form tumors in the mice and showed dissemination patterns in the SCID mouse comparable to those of T‐ALL in man: i.e., human cells were detectable by flow cytpmetry or were cultured from mouse bone marrow, spleen, liver or thymus. CEM, which is the most immature T‐cell line, readily formed tumors after injection of cells. The more mature T‐cell lines, SUP‐T3 and MOLT‐4f, required a longer time period, even after injection of higher cell numbers. Whereas no changes in the configuration of the rearranged T‐cell receptor genes were detected, striking phenotypic changes were observed in all 3 leukemias growing in the SCID mice after injection. SCID‐CEM cells showed an increase in the surface expression of CD3 and CDS and a decrease in the expression of CD1 and CD71 (transferrin‐receptor). SCID‐MOLT‐4f cells showed an increase in CD5 and CD5 expression and a decrease in CD45RA expression. SCID‐SUP‐T3 cells showed increased expression of CD5 and CD45RA. Apparently, the mouse environment caused changes in cell‐surface antigen expression on the T‐ALL‐derived T‐cell lines. Some immunophenotypic changes remained stable during subsequent growth in culture of SUP‐T3 cells, suggesting that maturation of the cell line occurred in vivo. The other cell lines, CEM and MOLT‐4f after undergoing in vivo‐induced changes, reverted to the original immunopheno‐type, suggesting transitory activation in vivo. These data point out the importance of stromal factors in defining growth and maturation of human leukemic cells in vivo, in SCID mice.
In vivo phenotypic characteristics of AKR T‐cell lymphomas with different leukemic potential: Possible role of α4β7 integrin in the progression towards the leukemic phenotype
Authors: Dolcetti R. , Frisan T. , Palmieri G. , Rizzo S. , Maestro R. , Santoni A. , Boiocchi M. 
Published: February 2007

AbstractThe present study was undertaken in order to determine whether the expression of specific surface molecules which mediate immune recognition as well as cell‐cell and cell‐matrix interactions is associated with the leukemic evolution of T‐cell lymphomas. To this end, we have investigated the in vivo phenotypic characteristics and the in vitro natural‐killer(NK)‐cell susceptibility of a group of MCF‐247‐induced AKR/J T‐cell lymphomas with different leukemic potential. We found that in the AKR/J model, the biological aggressiveness of leukemic cells is not dependent upon an escape from host immune surveillance as a consequence of an in vivo down‐regulation of H2‐Kk determinants or a resistance to NK lysis. Moreover, NK susceptibility of AKR/J lymphomas does not seem to correlate with the level of H2‐antigen expression. No obvious correlation was found between the leukemic phenotype and the amount of MEL‐14, LFA‐1, ICAM‐1, Pgp‐1/CD44 and THAM/CD26 antigen expression. An in vivo coordinated up‐regulation of α4 and β7 integrin chains, with the highest levels of expression detected in secondary sites of leukemic infiltration, was observed in the highly leukemic lymphoma NQ22 and, albeit to a lesser extent, in lymphomas with moderate leukemic potential. Conversely, non‐leukemic lymphomas were repeatedly α4‐and β7‐negative. These findings suggest that in the AKR/j system the expression of α4 β7 integrin may contribute to leukemic spreading of T‐cell lymphomas.
The role of protein kinase C isoenzymes in the growth inhibition caused by bryostatin 1 in human A549 lung and MCF‐7 breast carcinoma cells
Authors: Tanwell Caroline S , Gescher Andreas , Bradshaw Tracey D. , Pettit George R. 
Published: February 2007

AbstractBryostatin I is a natural product currently under clinical evaluation as an antitumor agent. Like the tumor‐promoting phorbol ester 12‐O‐tetradecanoylphorbol‐13 ‐acetate (TPA) it activates protein kinase C (PKC). Bryostatin I inhibits the growth of the human‐derived A549 lung and MCF‐7 adenocarci‐noma cell lines, but much more weakly than TPA. The hypotheses were tested that differences between cell lines in their response to bryostatin I are related to cellular PKC isotype content, and that differences between TPA and bryostatin I in their effects on cell growth are associated with differential abilities to modulate specific PKC isoenzymes. PKC isozyme profiles were studied by Western‐blot analysis in the cytosol, particulate and nuclear fractions of A549 and MCF‐7 cells. PKCs‐α, −ϵ and −ζ were detected in both cell types with predominant location in the cytosol. Separation of cytosolic PKC isoenzymes in A549 cells by hydroxylapatite column chromatography and determination of PKC activity in fractions yielded a major peak which contained PKC‐α. Exposure of cells to bryostatin I or TPA for 30 min caused the redistribution of PKCs‐α and −ϵ from the cytosol to the particulate and nuclear fractions in a concentration‐dependent fashion. PKC −ϵ was completely down‐regulated by exposure to 10 nM bryostatin I for 18 hr or to TPA for 24 hr. Down‐regulation of PKC‐α was partial at 10 nM and complete at I μM of either agent. Bryostatin I inhibited incorporation of [3H]‐labelled thymidine into cells only transiently, whereas TPA arrested growth for several days in A549 cells and irreversibly in MCF‐7 cells. A549 cells, in which PKC was depleted by exposure to phorbol ester for 9 weeks, were resistant towards bryostatin‐induced inhibition of DNA synthesis. The results suggest that the susceptibility of adenocarcinpma cells towards bryostatin‐induced growth delay are determined by cellular levels of PKCs‐α and/or −ϵ. However, differences between bryostatin I and TPA in their abilities to inhibit cell growth do not seem to be intrinsically related to differences in redistribution or down‐regulation of specific PKC isoenzymes.
TGF‐α can act as morphogen and/or mitogen in a colon‐cancer cell line
Authors: Liu Dan , Gagliardi Giuseppe , Nasim Mansoor M. , Alison Malcolm R. , Oates Tim , Lalani El‐Nasir , Stamp Gordon W. H. , Pignatelli Massimo 
Published: February 2007

AbstractTransforming growth factor alpha (TGF‐α) has multifunctional biological effects on a variety of mesenchymal and epithelial cells. It is a potent mitogen for a number of normal and transformed cell types, regulates extracellular matrix (ECM) production and promotes breast, kidney and lung morphogenesis. To clarify the role of ECM proteins in the morphogenetic and mitogenic effects of TGF‐α, we have used a human colon carcinoma cell line (SW1222) which expresses EGF receptor. Here we show, that TGF‐α at 1 ng/ml increases the proliferation of SW1222 cells, but only when they are cultured on plastic rather than collagen‐coated plates. Higher concentrations of TGF‐α (10ng/ml) did not increase cell proliferation but significantly enhanced the crypt‐like glandular differentiation when cells were grown in 3‐dimensional collagen gel (p = 0.027). These effects were accompanied by increased expression of α2β1 and α3β1 integrin molecules, which are receptors for extracellular matrix proteins, and by a statistically significant increase in binding of SW1222 cells to type‐1 collagen. The effects of TGF‐α both on binding to type‐1 collagen and on morphological differentiation in 3‐dimensional collagen gel were inhibited by monoclonal antibodies recognizing the α2β1 integrin. These data indicate that the morphogenetic or mitogenic activities of TGF‐α are critically dependent on cellular interactions with extracellular matrix proteins and are primarily mediated by the α2β1 integrin receptor. Inappropriate expression of this growth factor, seen in tumours whose cell‐matrix interactions are greatly impaired, could have deleterious effects on the maintenance of normal tissue architecture and growth control.
Genome amplification of human papillomavirus types 16 and 18 in cervical carcinomas is related to the retention of E1/E2 genes
Authors: Berumen Jaime , Casas Leonora , Segura Erika , Amezcua José L. , Garcia‐Carranca Alejandro 
Published: February 2007

AbstractThe level of amplification (copy number/cell) of HPV16 and HPV18 viral genomes and its correlation with the presence of E1/E2 genes were analyzed in a sample of 42 HPV16‐and 21 HPV18‐positive cervical carcinomas of different clinical stages and histological types. The viral copy number/cell was assessed by dot‐blot hybridization and the presence of E1/E2 genes by PCR and Southern blot. The copy number/cell was significantly lower in HPV18‐positive than in HPV16‐postive tumours (23 ∓ 8 and 457 ∓ 191 respectively). Nearly half of the HPV16s (43%) were distributed similarly to the HPV18s in the ranges of 50 or less copies, having its peak at the group of 1 to 10 copies, whereas the remaining HPV16s (57%) spread over the groups of 51 or more copies, with another peak at the group of 101 to 500. The E1/E2 region was absent in all tumours positive for HPV18 and present in 64% of those positive for HPV16. The HPV16 tumours negative for E1 /E2 had a much lower viral copy number (17 ∓ 12) than the positive ones (582 ∓ 212), thus resembling HPV18‐positive tumours. Viral copy number was negatively correlated with the clinical stage of the tumours and directly associated with the degree of histological differentiation. However, these correlations are primarily attributable to the presence or absence of an intact E1/E2 region.
Verapamil decreases P‐glycoprotein expression in multidrug‐resistant human leukemic cell lines
Authors: Muller Catherine , Bailly Jean‐Denis , Goubin Françoise , Laredo Judith , Jaffrézou Jean‐Pierre , Bordier Christine , Laurent Guy 
Published: February 2007

AbstractWe studied the effect of verapamil on Pgp expression (Pgp) in MDR human leukemia cell lines, K562/ADR and CEM VLB100. In the K562/ADR cell line, addition of verapamil to the culture medium (15μ M concentration) resulted in a 3‐fold decrease in Pgp expression after 72 hr exposure. The effect of verapamil was reversible, and Pgp expression reached the level of untreated controls 24 hr after discontinuation of verapamil. Similar results were obtained with the human vinblastine‐resistant cell line, CEM VLB100. On the contrary, no effect on Pgp expression was observed when the cells were treated with nifedipine or diltiazem (2 other calcium‐channel blockers), even at doses that inhibited cell proliferation. The level of Pgp mRNA in the presence of verapamil was measured by Northern blot and was also decreased 2‐fold (with the maximum reached within 24 hr), suggesting a transcriptional or post‐transcriptional mechanism for verapamil. We further established that the effect of verapamil on Pgp expression led to an increase in DNR and VLB accumulation and cytotoxicity. These results suggest that verapamil acts specifically on Pgp expression in these drug‐selected leukemic cells. The identification of a potentially novel mechanism of action may provide new insights as to how chemosensitization may be more effectively applied in vivo.
Production of IL‐10 by melanoma cells: Examination of its role in immunosuppression mediated by melanoma
Authors: Chen Qiyuan , Daniel Vincent , Maher Darryl W. , Hersey Peter 
Published: February 2007

AbstractPrevious studies have shown that IL‐10 may modulate immune responses towards the humoral arm by inhibiting production of cytokines involved in cell‐mediated responses. In the present studies, we found that mRNA to IL‐10 could be demonstrated in 66% of melanoma cell lines by PCR amplification of reverse‐transcribed mRNA and in supernatant of the cell lines by ELISA. Release into the supernatants increased approximately 2‐fold each day up to 3 days. The MW of 35S‐labelled IL‐10 secreted by melanoma cells was similar to that reported in previous studies. In the present studies we also examined whether IL‐10 may be responsible for some of the immunosuppressive effects of the melanoma cell supernatants observed in previous studies, by testing whether MAbs against IL‐10 could reverse the inhibitory effects of these supernatants. Recombinant IL‐10 and melanoma supernatants were found to inhibit production of TNF‐α, IFN‐γ, IL‐2 and mixed lymphocyte reactions but reversal of these effects of melanoma supernatants by MAbs against IL‐10 was only seen in the case of TNF‐α production. These results extend the range of cell types known to produce IL‐10 and indicate that malignancy of certain cell types may lead to unregulated production of IL‐10 that could have the potential to modulate immune responses against the tumor.
Retinoic acid up‐regulates nuclear retinoic acid receptor‐α expression in human neuroblastoma cells
Authors: Wuarin Laura , Chang Bieshia , Wada Randal , Sidell Neil 
Published: February 2007

AbstractRetinoic acid (RA) nuclear receptors (RARs) are thought to mediate the cellular and molecular effects of RA on a wide variety of tissues. In most cell types, RARα expression remains relatively constant following exposure to RA, while that of RARβ is rapidly induced. In this study, we show that in human neuroblastoma, a cell type exceptionally sensitive to RA‐induced differentiation, RARα as well as RARβ is markedly up‐regulated by RA treatment. This effect was consistent in all 5 neuroblastoma cell lines tested and was reflected in a 2‐to 5‐fold increase in receptor mRNA levels as assessed by Northern‐blot analysis. Using LA‐N‐5 human neuroblastoma cells, we found that receptor up‐regulation occurred in a time‐and dose‐dependent fashion with increases in both RARα and β mRNA detectable 1–2 hr after the addition of RA. These inductions were not abrogated by cycloheximide, indicating that protein synthesis was not required for the RA responses. Nuclear run‐off experiments combined with Northern‐blot analysis of RARα stability directly demonstrated that the up‐regulation of RARα mRNA levels reflected an increased rate of transcription without changes in message half‐life. These findings, showing direct activation by RA of RARα gene transcription in human neuroblastoma cells, suggest differences in the overall regulation of this receptor from that found in most other RA‐inducible tissue.
The LFA‐1/ICAM cell adhesion pathway is involved in tumor‐cell lysis mediated by bispecific monoclonal‐antibody‐targeted T lymphocytes
Authors: Ferrini Silvano , Sforzini Sabrina , Cambiaggi Anna , Poggi Alessandro , Meazza Raffaella , Canevari Silvana , Colnaghi Maria Ines , Moretta Lorenzo 
Published: February 2007

AbstractWe investigated the role of the LFA‐1 /ICAM, VLA‐4/VCAM‐1 and CD2/LFA‐3 adhesion pathways in the cytolysis of tumor cells mediated by an anti‐EGF‐R/anti‐CD3 bispecific monoclonal antibody (biMAb). The biMAb induced efficient lysis of EGF‐R+ tumor cells (A431, HT‐29, IGROV‐1 and MDA‐MB468) by cytotoxic T lymphocytes (CTL) cultured in IL‐2. Protreatment of effector cells by anti‐LFA‐1α (CDI 1a) and anti‐LFA‐1 β (CD 18) MAbs significantly inhibited cytolysis of all types of EGF‐R+ tumor cells, while anti‐CD2 and anti‐VLA‐4 MAbs were virtually ineffective. We investigated the expression of adhesion‐molecule counter‐receptors on tumor target cells by indirect immunofluorescence. HT‐29, A431 and MDA‐MB 468 tumor cells expressed an ICAM‐1+2−3−VCAM‐1−LFA‐3+ phenotype, while IGROV‐1 was ICAM‐1−2+3−VCAM‐1 −LFA‐3+. Pre‐treatment of A431, HT‐29 and MDA‐MB468 with anti‐ICAM‐1 MAb inhibited cytolysis, further supporting the functional involvement of the LFA‐1 /ICAM adhesion pathway in biMAb‐targeted tumor‐cell lysis. In addition, treatment of target cells with TNFα or IFN‐γ for 24 hr increased the expression of ICAM‐1 in HT‐29, A431 and MDA‐MB468 (ICAM‐2 was induced on IGROV‐1) and also enhanced the sensitivity of these target cells to biMAb‐targeted cytotoxicity. These data suggest that up‐regulation of ICAM‐molecule expression by inflammatory cytokines may increase susceptibility of tumor cells to biMAb‐targeted lysis. Anti‐LFA‐1 MAbs did not significantly inhibit the formation of conjugates between biMAb‐coated T lymphocytes and tumor cells. Co‐aggregation of LFA‐1 molecules with biMAb‐bound CD3 molecules resulted in a more sustained and prolonged increase in the intracellular concentration of. free Ca++ in CD8+ cultured CTL lines. These findings indicate that in T cells targeted by anti‐CD3/anti‐TAA biMAb LFA‐1 may act as a co‐receptor molecule which enhances signal transduction through the CD3/TCR complex.
Clofazimine alters the energy metabolism and inhibits the growth rate of a human lung‐cancer cell line in vitro and in vivo
Authors: Sri‐Pathmanathan Rohendra M. , Plumb Jane A. , Fearon Kenneth C. H. 
Published: February 2007

AbstractThe anti‐leprosy drug Clofazimine is known to inhibit respiratory function and hence energy metabolism in yeast and in transformed fibroblasts. The aim of this study was to examine the effect of Clofazimine on the energy metabolism of a chemoresistant human non‐small‐cell bronchial‐carcinoma cell line (WIL) and to determine whether this agent might inhibit the growth rate of this cell line in vitro and in vivo. Oxidative phosphorylation was estimated in vitro by measuring oxygen consumption polarographically and glycolysis was estimated from lactate production. In cells that had been pre‐treated with an ATP synthetase inhibitor (oligomycin), the addition of Clofazimine resulted in an increase in oxygen consumption similar to that observed with 2,4‐dinitrophenol, a classical inhibitor of oxidative phosphorylation. This inhibition of mitochondrial function was associated with an increase in lactate production. Cellular ATP levels were maintained, possibly indicating a compensatory increase in ATP production via glycolysis. Clofazimine was shown to have a direct cytotoxic effect in vitro with an ID50 of 10.2 μM‐When Clofazimine was administered to athymic mice bearing WIL as a subcutaneous xenograft, tumour growth rate was significantly reduced, so that after 3 weeks, tumour size was one third that of controls (p < 0.01). These results suggest that selective inhibition of tumour energy metabolism with agents such as Clofazimine is a potential novel approach to cancer treatment.
Differential induction of the two early genes c‐jun and c‐fos in weakly and strongly metastatic murine lymphoma cell lines
Authors: Rossi Dunicla , Fumagalli Stefano , Volpi Ludovica , Larizza Lidia 
Published: February 2007

AbstractInduction of the 2 early‐response genes c‐jun and c‐fos was investigated in the weakly metastatic T‐lymphoma Eb line and the related strongly metastatic lymphomacrophage ESb line to find possible correlations with their different in vitro and in vivo phenotypes. The response of c‐jun was elicited by the protein kinase‐C activators TPA and A23187 in ESb but not in Eb cells. A much lower response of c‐fos was also found in Eb than in ESb cells, in this case by means of scrum and the cAMP elevator forskolin. However, both TPA and the calcium ionophore A23187 were similarly effective in inducing fos‐mRNA in both cell lines. The uncoupling of c‐jun and c‐fos induction in Eb, but not in ESb cells, as well as the uncoupling of c‐fos response to different stimulators, point to a differential activation of these 2 early‐response genes by the main signal transduction pathways in the 2 cell types. The coordinate/uncoordinate availability of the fos/jun heterodimer may confer distinct regulatory patterns on different target genes in ESb/Eb cells. Activation of these genes may underlie the distinct differentiation phenotypes and in vivo behavior of Eb/ESb cells. © Wiley‐Liss, Inc.