bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bcl-2 Overexpression Enhances Tumor-Specific T-Cell Survival
Authors: Charo Jehad , Finkelstein Steven E. , Grewal Navrose , Restifo Nicholas P. , Robbins Paul F. , Rosenberg Steven A. 
Published: September 2005

AbstractAlthough immunotherapy based on the adoptive transfer of tumor-specific T lymphocytes has been shown to result in dramatic clinical responses in some patients, the relatively low levels of engraftment and persistence of the adoptively transferred cells may limit these responses in many patients. In an attempt to develop strategies for prolonging the survival of adoptively transferred T cells, we have carried out studies in which T cells obtained from healthy donors as well as tumor-specific T cells were transduced with a retrovirus expressing the human Bcl-2 gene. Our results indicate that these transduced T cells overexpress Bcl-2, are resistant to death, and have a survival advantage following interleukin-2 withdrawal compared with control T cells transduced with a retrovirus expressing green fluorescent protein. Tumor-specific T cells overexpressing Bcl-2 maintained their ability to specifically recognize and respond to target cells. Furthermore, we show that adoptive immunotherapy of an established B16 tumor can be significantly enhanced by overexpressing Bcl-2 in melanoma-specific T-cell receptor transgenic T cells. Our data suggest that adoptive immunotherapy approaches to the treatment of cancer patients may be enhanced using Bcl-2-modified tumor-reactive T cells.
Mitotic Infidelity and Centrosome Duplication Errors in Cells Overexpressing Tripeptidyl-Peptidase II
Authors: Stavropoulou Vaia , Xie Jianjun , Henriksson Marie , Tomkinson Birgitta , Imreh Stefan , Masucci Maria G. 
Published: September 2005

AbstractThe oligopeptidase tripeptidyl-peptidase II (TPP II) is up-regulated Burkitt's lymphoma (BL) cells that overexpress the c-myc proto-oncogene and is required for their growth and survival. Here we show that overexpression of TPP II induces accelerated growth and resistance to apoptosis in human embryonic kidney 293 cells. This correlates with the appearance of multiple chromosomal aberrations, numerical and structural centrosome abnormalities, and multipolar cell divisions. Similar mitotic aberrations were also observed in a panel of BL lines and were suppressed, in parallel with TPP II down-regulation, upon reversion of BL-like characteristics in EBV-immortalized B lymphocytes carrying a tetracycline-regulated c-myc. Functional TPP II knockdown by small interfering RNA expression in BL cells caused the appearance of giant polynucleated cells that failed to complete cell division. Collectively, these data point to a role of TPP II in the regulation of centrosome homeostasis and mitotic fidelity suggesting that this enzyme may be a critical player in the induction and/or maintenance of genetic instability in malignant cells.
Up-regulation of Inhibitory Natural Killer Receptors CD94/NKG2A with Suppressed Intracellular Perforin Expression of Tumor-Infiltrating CD8+ T Lymphocytes in Human Cervical Carcinoma
Authors: Sheu Bor-Ching , Chiou Shin-Heng , Lin Ho-Hsiung , Chow Song-Nan , Huang Su-Cheng , Ho Hong-Nerng , Hsu Su-Ming 
Published: September 2005

AbstractInhibitory signals that govern the cytolytic functions of CD8+ T lymphocytes have been linked to the expression of natural killer cell receptors (NKRs) on CTLs. There is limited knowledge about the induction of inhibitory NKR (iNKR) expression in vivo. Up-regulation of iNKRs has been linked to the modulation of the virus- and/or tumor-specific immune responses in animal models. In the present study, we directly examined the expression of various NKRs on tumor-infiltrating lymphocytes (TILs) derived from human cervical cancer. We found that in human cervical cancer, the percentage expression of immunoglobulin-like NKR+CD8+ T lymphocytes were similar in gated CD8+-autologous TILs and peripheral blood mononuclear cells. On the contrary, cervical cancer–infiltrating CD8+ T lymphocytes expressed up-regulated C-type lectin NKRs CD94/NKG2A compared with either peripheral blood CD8+ T cells or normal cervix-infiltrating CD8+ T lymphocytes. Dual NKR coexpression analyses showed that CD94 and NKG2A were mainly expressed on CD56−CD161−CD8+ TILs within the cancer milieu. Immunohistochemical study showed that cervical cancer cells expressed abundant interleukin 15 (IL-15) and transforming growth factor-β (TGF-β). In kinetic coculture assay, cervical cancer cells can promote the expression of CD94/NKG2A on CD8+ T lymphocytes. The cancer-derived effects can be reversed by addition of rIL-15Rα/Fc and anti–TGF-β antibody. Functional analyses illustrated that intracellular perforin expression of CD8+ T cells was minimal upon up-regulation of CD94/NKG2A. Kinetic cytotoxicity assays showed that up-regulated expressions of CD94/NKG2A restrain CD8+ T lymphocyte cytotoxicity. Our study strongly indicated that cervical cancer cells could promote the expression of iNKRs via an IL-15– and possibly TGF-β–mediated mechanism and abrogate the antitumor cytotoxicity of TILs.
Chemoprevention of UV Light-Induced Skin Tumorigenesis by Inhibition of the Epidermal Growth Factor Receptor
Authors: El-Abaseri Taghrid B. , Fuhrman Jill , Trempus Carol , Shendrik Igor , Tennant Raymond W. , Hansen Laura A. 
Published: September 2005

Abstract
The epidermal growth factor receptor (EGFR) is activated in skin cells following UV irradiation, the primary cause of nonmelanoma skin cancer. The EGFR inhibitor AG1478 prevented the UV-induced activation of EGFR and of downstream signaling pathways through c-Jun NH2-terminal kinases, extracellular signal-regulated kinases, p38 kinase, and phosphatidylinositol 3-kinase in the skin. The extent to which the UV-induced activation of EGFR influences skin tumorigenesis was determined in genetically initiated v-rasHa transgenic Tg.AC mice, which have enhanced susceptibility to skin carcinogenesis. Topical treatment or i.p. injection of AG1478 before UV exposure blocked the UV-induced activation of EGFR in the skin and decreased skin tumorigenesis in Tg.AC mice. AG1478 treatment before each of several UV exposures decreased the number of papillomas arising and the growth of these tumors by ∼50% and 80%, respectively. Inhibition of EGFR suppressed proliferation, increased apoptotic cell death, and delayed the onset of epidermal hyperplasia following UV irradiation. Genetic ablation of Egfr similarly delayed epidermal hyperplasia in response to UV exposure. Thus, the UV-induced activation of EGFR promotes skin tumorigenesis by suppressing cell death, augmenting cell proliferation, and accelerating epidermal hyperplasia in response to UV. These results suggest that EGFR may be an appropriate target for the chemoprevention of UV-induced skin cancer.
Synergistic Antitumor Response of Interleukin 2 with Melphalan in Isolated Limb Perfusion in Soft Tissue Sarcoma–Bearing Rats
Authors: Hoving Saske , Brunstein Flavia , aan de Wiel-Ambagtsheer Gisela , van Tiel Sandra T. , de Boeck Gert , de Bruijn Ernst A. , Eggermont Alexander M.M. , ten Hagen Timo L.M. 
Published: September 2005

Abstract
The cytokine interleukin 2 (IL-2) is a mediator of immune cell activation with some antitumor activity, mainly in renal cell cancer and melanoma. We have previously shown that tumor necrosis factor (TNF)-α has strong synergistic antitumor activity in combination with chemotherapeutics in the isolated limb perfusion (ILP) setting based on a TNF-mediated enhanced tumor-selective uptake of the chemotherapeutic drug followed by a selective destruction of the tumor vasculature. IL-2 can cause vascular leakage and edema and for this reason we examined the antitumor activity of a combined treatment with IL-2 and melphalan in our well-established ILP in soft tissue sarcoma–bearing rats (BN175). ILP with either IL-2 or melphalan alone has no antitumor effect, but the combination of IL-2 and melphalan resulted in a strong synergistic tumor response, without any local or systemic toxicity. IL-2 enhanced significantly melphalan uptake in tumor tissue. No signs of significant vascular damage were detected to account for this observation, although the tumor sections of the IL-2– and IL-2 plus melphalan–treated animals revealed scattered extravasation of erythrocytes compared with the untreated animals. Clear differences were seen in the localization of ED-1 cells, with an even distribution in the sham, IL-2 and melphalan treatments, whereas in the IL-2 plus melphalan–treated tumors clustered ED-1 cells were found. Additionally, increased levels of TNF mRNA were found in tumors treated with IL-2 and IL-2 plus melphalan. These observations indicate a potentially important role for macrophages in the IL-2–based perfusion. The results in our study indicate that the novel combination of IL-2 and melphalan in ILP has synergistic antitumor activity and may be an alternative for ILP with TNF and melphalan.
Sensitivity of Undifferentiated, High-TCR Density CD8+ Cells to Methylene Groups Appended to Tumor Antigen Determines Their Differentiation or Death
Authors: Kawano Kouichiro , Efferson Clay L. , Peoples George E. , Carter Darrick , Tsuda Naotake , Murray James L. , Ioannides Constantin G. 
Published: September 2005

AbstractCD8+ cells expressing high numbers of TCR per cell (TCRhi) are considered important mediators of antitumor effects. To understand the relationship between TCR density and antigen affinity for TCR in the outcome of stimulation with antigen and differentiation of CTL recognizing tumor antigen, we analyzed perforin induction in ovarian tumor-associated lymphocytes in response to the smallest possible changes in the atomic forces of interaction between antigen and TCR. Stimulating undifferentiated, apoptosis-resistant CD8+ cells expressing high levels of E75-TCR (TCRhi) with variants of the CTL epitope E75, HER-2 (369-377), induced their stepwise differentiation, first to IFN-γ+ Perf− and to TCRhi IFN-γ+ Perf+ cells. Blocking caspase-9 activation at antigen stimulation also enhanced the generation of TCRhi Perfhi cells, demonstrating that TCR density dictated the pathway of death activated by stimulation with the same agonist. Expansion and differentiation of TCRhi Perf+ CTL required an agonist of optimal CH2 side chain length, which in this study was equal to two CH2 groups appended to E75 at the Gly4 position. Side chains one CH2 shorter or longer than optimal were either less stimulatory or induced death of TCRhi Perf+ cells. Differentiation of TCRhi CD8+ cells can be finely tuned by synthetic amino acids in the peptide, whose side chains induce small increments in the affinity of the antigen for TCR below the affinity which induce apoptosis.
The G Protein–Coupled Receptor S1P2 Regulates Rho/Rho Kinase Pathway to Inhibit Tumor Cell Migration
Authors: Lepley Denise , Paik Ji-Hye , Hla Timothy , Ferrer Fernando 
Published: September 2005

Abstract
Sphingosine 1-phosphate (S1P) is a lysophospholipid that exerts a variety of responses in cells such as proliferation, migration, and survival. These effects are mediated by G protein–coupled receptors on the cell surface (S1P1-5), which activate downstream signaling intermediates such as Rac and Rho GTPases. Mechanisms of S1P action in human glioblastoma cells are not well defined. S1P receptors (1–5) and S1P-metabolizing enzymes were expressed in three human glioblastoma cell lines. S1P had a profound and differential effect on glioblastoma cell migration. U87 cells treated with S1P showed a significant increase in migration, whereas U118 and U138 cell lines were strongly inhibited. S1P-mediated inhibition correlated with S1P2 receptor expression. FTY720-P, an S1P analogue that binds all S1P receptors except S1P2, did not inhibit glioblastoma cell migration. Overexpression of S1P2 further suppressed migration, and blockage of S1P2 mRNA expression by small interfering RNA reversed the inhibitory effect. Contrary to previous reports showing bimodal regulation of Rac activity and migration by S1P2 receptor stimulation, both Rac1 and RhoA GTPases were activated by S1P treatment in native cells and cells overexpressing S1P2. Treatment of U118 cells with the Rho-associated protein kinase (ROCK) inhibitor Y-27632 restored migration suggesting that ROCK-dependent mechanisms are important. Actin staining of S1P stimulated U118 cells overexpressing β-galactosidase resulted in pronounced stress fiber formation that was exacerbated by S1P2 overexpression, partially blocked by S1P1, or totally abolished by pretreatment with Y-27632. These data provide evidence of a novel mechanism of S1P inhibition of tumor cell migration via Rho kinase–dependent pathway.
Valproic Acid Alters Chromatin Structure by Regulation of Chromatin Modulation Proteins
Authors: Marchion Douglas C. , Bicaku Elona , Daud Adil I. , Sullivan Daniel M. , Munster Pamela N. 
Published: September 2005

Abstract
Histone acetylation and deacetylation are crucial in the regulation of gene expression. Dynamic changes in gene expression may affect chromatin structure and, consequently, the interaction of chromatin with regulatory factors. In this study, the effects of the antiseizure drug valproic acid (VPA) on the expression of genes that regulate the structure of chromatin and the access of macromolecules to the DNA were investigated. Exposure of breast cancer cells to VPA resulted in rapid dose-dependent hyperacetylation of the histones H3 and H4. VPA further induced a depletion of several members of the structural maintenance of chromatin (SMC) proteins, SMC-associated proteins, DNA methyltransferase, and heterochromatin proteins. Down-regulation of these proteins was associated with chromatin decondensation. The observed alterations of chromatin structure correlated with enhanced sensitivity of DNA to nucleases and increased interaction of DNA with intercalating agents. VPA-induced chromatin decondensation led to a sequence-specific potentiation of DNA-damaging agents in cell culture and xenograft models. Modulation of heterochromatin maintenance proteins was not a direct, but a downstream, effect of histone acetylation. The effects on the chromatin structure were reversible upon drug withdrawal, but obligatory for the potentiation of DNA-damaging agents. In addition to their antitumor activity as single agents, the chromatin decondensation induced by histone deacetylase inhibitors may enhance the efficacy of cytotoxic agents that act by targeting DNA. The proposed mechanism of action suggests an effect of drug sequencing on the antitumor activity of these drugs.
RNA Silencing of Checkpoint Regulators Sensitizesp53-Defective Prostate Cancer Cells to Chemotherapy while Sparing Normal Cells
Authors: Mukhopadhyay Utpal K. , Senderowicz Adrian M. , Ferbeyre Gerardo 
Published: September 2005

Abstractp53 is frequently mutated in patients with prostate cancer, especially in those with advanced disease. Therefore, the selective elimination of p53 mutant cells will likely have an impact in the treatment of prostate cancer. Because p53 has important roles in cell cycle checkpoints, it has been anticipated that modulation of checkpoint pathways should sensitize p53-defective cells to chemotherapy while sparing normal cells. To test this idea, we knocked down ataxia telangiectasia mutated (ATM) gene by RNA interference in prostate cancer cell lines and in normal human diploid fibroblasts IMR90. ATM knockdown in p53-defective PC3 prostate cancer cells accelerated their cell cycle transition, increased both E2F activity and proliferating cell nuclear antigen expression, and compromised cell cycle checkpoints, which are normally induced by DNA damage. Consequently, PC3 cells were sensitized to the killing effects of the DNA-damaging drug doxorubicin. Combining ATM knockdown with the Chk1 inhibitor UCN-01 further increased doxorubicin sensitivity in these cells. In contrast, the same strategy did not sensitize either IMR90 or LNCaP prostate cancer cells, both of which have normal p53. However, IMR90 and LNCaP cells became more sensitive to doxorubicin or doxorubicin plus UCN-01 when both p53 and ATM functions were suppressed. In addition, knockdown of the G2 checkpoint regulators ATR and Chk1 also sensitized PC3 cells to doxorubicin and increased the expression of the E2F target gene PCNA. Together, our data support the concept of selective elimination of p53 mutant cells by combining DNA damage with checkpoint inhibitors and suggest a novel mechanistic insight into how such treatment may selectively kill tumor cells.
Mouse Mammary Tumor Virus Infects Human Cells
Authors: Indik Stanislav , Günzburg Walter H. , Salmons Brian , Rouault Francoise 
Published: September 2005

Abstract
Mouse mammary tumor virus (MMTV) has long been speculated to be involved in human breast cancer and more recently in human primary biliary cirrhosis. Despite complete proviral sequences markedly homologous to MMTV being identified in human breast cancer tissue, no convincing evidence has been presented to date that MMTV can infect human cells. Using both wild-type and a genetically marked virus (MMTV-EGFP), we show here the successful infection of a number of different human cells by MMTV. Furthermore, infection of human cells is shown to be almost as efficient as the infection of murine mammary epithelial cells. Sequencing of PCR products from integrated proviruses reveals that reverse transcription and integration of the viral genome has occurred as expected. Furthermore, sequencing of two independent MMTV proviral integration sites reveal them to be present only in the human and not in the mouse genome. Infection requires an intact MMTV envelope protein and is blocked either by heat inactivation of the virus or by specific neutralizing anti-MMTV serum, ruling out a nonspecific mechanism of viral transfer. Thus, MMTV can infect human cells and this finding provides a possible explanation for the detection by others of MMTV sequences in human breast cancer patients.
Regulation of p38 Phosphorylation and Topoisomerase IIα Expression in the B-Cell Lymphoma Line Jiyoye by CD26/Dipeptidyl Peptidase IV Is Associated with EnhancedIn vitroandIn vivoSensitivity to Doxorubicin
Authors: Yamochi Toshiko , Yamochi Tadanori , Aytac Ugur , Sato Tsutomu , Sato Kazuya , Ohnuma Kei , McKee Kathryn S. , Morimoto Chikao , Dang Nam H. 
Published: September 2005

AbstractCD26 is a Mr 110,000 surface-bound glycoprotein with diverse functional properties, including having a key role in normal T-cell physiology and the development of certain cancers. In this article, we show that surface expression of CD26, especially its intrinsic dipeptidyl peptidase IV (DPPIV) enzyme activity, results in enhanced topoisomerase IIα level in the B-cell line Jiyoye and subsequent in vitro sensitivity to doxorubicin-induced apoptosis. In addition, we show that expression of CD26/DPPIV is associated with increased phosphorylation of p38 and its upstream regulators mitogen-activated protein kinase kinase 3/6 and apoptosis signal-regulating kinase 1 and that p38 signaling pathway plays a role in the regulation of topoisomerase IIα expression. Besides demonstrating that CD26 effect on topoisomerase IIα and doxorubicin sensitivity is applicable to cell lines of both B-cell and T-cell lineages, the potential clinical implication of our work lies with the fact that we now show for the first time that our in vitro results can be extended to a severe combined immunodeficient mouse model. Our findings that CD26 expression can be an in vivo marker of tumor sensitivity to doxorubicin treatment may lead to future treatment strategies targeting CD26/DPPIV for selected human cancers in the clinical setting. Our article thus characterizes the biochemical linkage among CD26, p38, and topoisomerase IIα while providing evidence that CD26-associated topoisomerase IIα expression results in greater in vitro and in vivo tumor sensitivity to the antineoplastic agent doxorubicin.
Akt Activation Suppresses Chk2-Mediated, Methylating Agent–Induced G2 Arrest and Protects from Temozolomide-Induced Mitotic Catastrophe and Cellular Senescence
Authors: Hirose Yuchi , Katayama Makoto , Mirzoeva Olga K. , Berger Mitchel S. , Pieper Russell O. 
Published: September 2005

Abstract
Pharmacologic inhibition of the DNA signal transducers Chk1 and p38 blocks G2 arrest and sensitizes glioblastoma cells to chemotherapeutic methylating agent–induced cytotoxicity. Because Akt pathway activation has been suggested to also block G2 arrest induced by DNA-damaging agents and because glioma cells frequently have high levels of Akt activation, we examined the contribution of the Akt pathway to methylating agent–induced G2 arrest and toxicity. U87MG human glioma cells containing an inducible Akt expression construct were incubated with inducing agent or vehicle, after which the cells were exposed to temozolomide and assayed for activation of the components of the G2 arrest pathway and survival. Temozolomide-treated control cells activated the DNA damage signal transducers Chk1, Chk2, and p38, leading to Cdc25C and Cdc2 inactivation, prolonged G2 arrest, and loss of clonagenicity by a combination of senescence and mitotic catastrophe. Temozolomide-treated cells induced to overexpress Akt, however, exhibited significantly less drug-induced Cdc25C/Cdc2 inactivation and less G2 arrest. Akt-mediated suppression of G2 arrest was associated not with alterations in Chk1 or p38 activation but rather with suppression of Chk2 activation and reduced recruitment of Chk2 to sites of damage in chromatin. Unlike bypass of the G2 checkpoint induced by pharmacologic inhibitors of Chk1 or p38, however, Akt-induced bypass of G2 arrest suppressed, rather than enhanced, temozolomide-induced senescence and mitotic catastrophe. These results show that whereas Akt activation suppresses temozolomide-induced Chk2 activation and G2 arrest, the overriding effect is protection from temozolomide-induced cytotoxicity. The Akt pathway therefore represents a new target for the sensitization of gliomas to chemotherapeutic methylating agents such as temozolomide.
Altered ErbB Receptor Signaling and Gene Expression in Cisplatin-Resistant Ovarian Cancer
Authors: Macleod Kenneth , Mullen Peter , Sewell Jane , Rabiasz Genevieve , Lawrie Sandra , Miller Eric , Smyth John F. , Langdon Simon P. 
Published: September 2005

AbstractThe majority of ovarian cancer patients are treated with platinum-based chemotherapy, but the emergence of resistance to such chemotherapy severely limits its overall effectiveness. We have shown that development of resistance to this treatment can modify cell signaling responses in a model system wherein cisplatin treatment has altered cell responsiveness to ligands of the erbB receptor family. A cisplatin-resistant ovarian carcinoma cell line PE01CDDP was derived from the parent PE01 line by exposure to increasing concentrations of cisplatin, eventually obtaining a 20-fold level of resistance. Whereas PE01 cells were growth stimulated by the erbB receptor-activating ligands, such as transforming growth factor-α (TGFα), NRG1α, and NRG1β, the PE01CDDP line was growth inhibited by TGFα and NRG1β but unaffected by NRG1α. TGFα increased apoptosis in PE01CDDP cells but decreased apoptosis in PE01 cells. Differences in extracellular signal-regulated kinase and phosphatidylinositol 3-kinase signaling were also found, which may be implicated in the altered cell response to ligands. Microarray analysis revealed 51 genes whose mRNA increased by at least 2-fold in PE01CDDP cells relative to PE01 (including FRA1, ETV4, MCM2, AXL, MT3, TRAP1, and FANCG), whereas 36 genes (including IGFBP3, TRAM1, and KRT4 and KRT19) decreased by a similar amount. Differential display reverse transcriptase-PCR identified altered mRNA expression for TCP1, SLP1, proliferating cell nuclear antigen, and ZXDA. Small interfering RNA inhibition of FRA1, TCP1, and MCM2 expression was associated with reduced growth and FRA1 inhibition with enhanced cisplatin sensitivity. Altered expression of these genes by cytotoxic exposure may provide survival advantages to cells including deregulation of signaling pathways, which may be critical in the development of drug resistance.