bluuebunny/crossref_metadata_2025 huggingface dataset:
Radiofrequency Thermal Ablation of Hepatocellular Carcinoma Liver Nodules Can Activate and Enhance Tumor-Specific T-Cell Responses
Authors: Zerbini Alessandro , Pilli Massimo , Penna Amalia , Pelosi Guido , Schianchi Claudia , Molinari Atim , Schivazappa Simona , Zibera Carlo , Fagnoni Francesco F. , Ferrari Carlo , Missale Gabriele
Published: January 2006

Radiofrequency thermal ablation (RFA) destroys tumoral tissue generating a local necrosis followed by marked inflammatory response with a dense T-cell infiltrate. In this study, we tested whether hepatocellular carcinoma thermal ablation can induce or enhance T-cell responses specific for hepatocellular carcinoma–associated antigens. Peripheral blood mononuclear cells derived from 20 patients with hepatocellular carcinoma were stimulated before and a month after RFA treatment with autologous hepatocellular carcinoma–derived protein lysates obtained before and immediately after RFA treatment. The effect of thermal ablation on memory T-cell responses to recall antigens [tetanus toxoid, protein purified derivative (PPD), Escherichia coli] was also assessed. T-cell reactivity was analyzed in an IFN-γ enzyme-linked immunospot assay and by intracellular IFN-γ staining. Treatment was followed by a significant increase of patients responsive either to tumor antigens derived from both the untreated hepatocellular carcinoma tissue (P < 0.05) and the necrotic tumor (P < 0.01) and by a higher frequency of circulating tumor-specific T cells. T-cell responses to recall antigens were also significantly augmented. Phenotypic analysis of circulating T and natural killer cells showed an increased expression of activation and cytotoxic surface markers. However, tumor-specific T-cell responses were not associated with protection from hepatocellular carcinoma relapse. Evidence of tumor immune escape was provided in one patient by the evidence that a new nodule of hepatocellular carcinoma recurrence was not recognized by T cells obtained at the time of RFA. In conclusion, RFA treatment generates the local conditions for activating the tumor-specific T-cell response. Although this effect is not sufficient for controlling hepatocellular carcinoma, it may represent the basis for the development of an adjuvant immunotherapy in patients undergoing RFA for primary and secondary liver tumors. (Cancer Res 2006; 66(2): 1139-46)
Tumor Cells Transduced with the MHC Class II Transactivator and CD80 Activate Tumor-Specific CD4+ T Cells Whether or Not They Are Silenced for Invariant Chain
Authors: Thompson James A. , Dissanayake Samudra K. , Ksander Bruce R. , Knutson Keith L. , Disis Mary L. , Ostrand-Rosenberg Suzanne
Published: January 2006

The specificity and potency of the immune system make immunotherapy a potential strategy for the treatment of cancer. To exploit this potential, we have developed cell-based cancer vaccines consisting of tumor cells expressing syngeneic MHC class II and costimulatory molecules. The vaccines mediate tumor regression in mice and activate human CD4+ T cells in vitro. Previous vaccines were generated by transducing MHC II negative tumor cells with a single HLA-DR allele. Because expression of multiple MHC II alleles would facilitate presentation of a broader repertoire of tumor antigens, we have now transduced tumor cells with the MHC class II transactivator (CIITA), a regulatory gene that coordinately increases expression of all MHC II alleles. Previous studies in mice indicated that coexpression of the MHC II accessory molecule invariant chain (Ii) inhibited presentation of endogenously synthesized tumor antigens and reduced vaccine efficacy. To determine if Ii expression affects presentation of MHC class II–restricted endogenously synthesized tumor antigens in human tumor cells, HLA-DR-MCF10 breast cancer cells were transduced with the CIITA, CD80 costimulatory molecule gene, and with or without small interfering RNAs (siRNA) specific for Ii. Ii expression is silenced >95% in CIITA/CD80/siRNA transductants; down-regulation of Ii does not affect HLA-DR expression or stability; and Ii+ and Ii− transductants activate human CD4+ T cells to DRB1*0701-restricted HER-2/neu epitopes. Therefore, tumor cells transduced with the CIITA, CD80, and with or without Ii siRNA present endogenously synthesized tumor antigens and are potential vaccines for activating tumor-specific CD4+ T cells. (Cancer Res 2006; 66(2): 1147-54)
Effect of Adenovirus-Mediated Heat Shock Protein Expression and Oncolysis in Combination with Low-Dose Cyclophosphamide Treatment on Antitumor Immune Responses
Authors: Di Paolo Nelson C. , Tuve Sebastian , Ni Shaoheng , Hellström Karl Erik , Hellström Ingegerd , Lieber André
Published: January 2006

Heat shock proteins such as gp96 have the ability to chaperone peptides and activate antigen-presenting cells. In this study, we tested whether adenovirus-mediated overexpression of secreted or membrane-associated forms of gp96 in tumor cells would stimulate an antitumor immune response. Studies were carried out in C57Bl/6 mice bearing aggressively growing s.c. tumors derived from syngeneic TC-1 cells, a cell line that expresses HPV16 E6 and E7 proteins. We found that secreted gp96 can induce protective and therapeutic antitumor immune responses. Our data also indicate that the antitumor effect of sgp96 expression seems to be limited by the induction of suppressive regulatory T cells (Treg). TC-1 tumor transplantation increased the number of splenic and tumor-infiltrating Tregs. Importantly, treatment of mice with low-dose cyclophosphamide decreased the number of Tregs and enhanced the immunostimulatory effect of sgp96 expression. We also tested whether an oncolytic vector (Ad.IR-E1A/TRAIL), that is able to induce tumor cell apoptosis and, potentially, release cryptic tumor epitopes in immunogenic form, could stimulate antitumor immune responses. Although tumor cells infected ex vivo with Ad.IR-E1A/TRAIL had no antitumor effect when used as a vaccine alone, the additional treatment with low-dose cyclophosphamide resulted in the elimination of pre-established tumors. This study gives a rationale for testing approaches that suppress Tregs in combination with oncolytic or immunostimulatory vectors. (Cancer Res 2006; 66(2): 960-9)
Targeting Cell-Impermeable Prodrug Activation to Tumor Microenvironment Eradicates Multiple Drug-Resistant Neoplasms
Authors: Wu Wenyuan , Luo Yunping , Sun Chengzao , Liu Yuan , Kuo Paul , Varga Janos , Xiang Rong , Reisfeld Ralph , Janda Kim D. , Edgington Thomas S. , Liu Cheng
Published: January 2006

The tumor microenvironment is notably enriched with a broad spectrum of proteases. The proteolytic specificities of peptide substrates provide modular chemical tools for the rational design of cell-impermeable prodrugs that are specifically activated by proteases extracellularly in the tumor microenvironment. Targeting cell-impermeable prodrug activation to tumor microenvironment will significantly reduce drug toxicity to normal tissues. The activated prodrug attacks both tumor and stroma cells through a “bystander effect” without selectively deleting target-producing cells, therefore further minimizing resistance and toxicity. Here, we showed that legumain, the only asparaginyl endopeptidase of the mammalian genome, is highly expressed by neoplastic, stromal, and endothelial cells in solid tumors. Legumain is present extracellularly in the tumor microenvironment, associated with matrix as well as cell surfaces and functional locally in the reduced pH of the tumor microenvironment. A novel legumain-activated, cell-impermeable doxorubicin prodrug LEG-3 was designed to be activated exclusively in the tumor microenvironment. Upon administration, there is a profound increase of the end-product doxorubicin in nuclei of cells in tumors but little in other tissues. This tumor microenvironment–activated prodrug completely arrested growth of a variety of neoplasms, including multidrug-resistant tumor in vivo and significantly extended survival without evidence of myelosuppression or cardiac toxicity. The tumor microenvironment–activated prodrug design can be extended to other proteases and chemotherapeutic compounds and provides new potentials for the rational development of more effective functionally targeted cancer therapeutics. (Cancer Res 2006; 66(2): 970-80)
Induction of Metastasis by S100P in a Rat Mammary Model and Its Association with Poor Survival of Breast Cancer Patients
Authors: Wang Guozheng , Platt-Higgins Angela , Carroll Joe , de Silva Rudland Suzete , Winstanley John , Barraclough Roger , Rudland Philip S.
Published: January 2006

S100P, an EF-hand calcium-binding protein, has been reported to be associated with the progression of many types of cancers. Transfection of an expression vector for S100P into a benign, nonmetastatic rat mammary cell line causes a 4- to 6-fold increase in its level in all four transformant cell clones. When the resultant transformant cell lines are introduced in turn into the mammary fat pads of syngeneic Furth-Wistar rats, there is a significant 3-fold increase in local muscle invasion and a significant induction of metastasis in 64% to 75% of tumor-bearing animals. In a group of 303 breast cancer patients followed for up to 20 years, antibodies to S100P immunocytochemically stain 161 primary tumors. Survival of patients with S100P-positive carcinomas is significantly worse by about 7-fold than for those with negatively stained carcinomas. There is also a significant association between the class level of immunocytochemical staining of the carcinoma cells and decreased patient survival. Positive staining for S100P is significantly associated with that for two other metastasis-inducing proteins, S100A4 and osteopontin. Patients with tumors that stained positively for both S100P and S100A4 have a significantly reduced survival of 1.1% over patients with either S100 protein alone. Multivariate regression analysis identifies S100P, S100A4, and osteopontin as the most significant independent indicators of death in this group of patients. These results suggest that stratification of patients into groups according to expression of multiple metastasis-inducing proteins may lead to a more accurate prediction of patient survival. (Cancer Res 2006; 66(2): 1199-207)
Protein Kinase C δ Overexpressing Transgenic Mice Are Resistant to Chemically but not to UV Radiation–Induced Development of Squamous Cell Carcinomas: A Possible Link to Specific Cytokines and Cyclooxygenase-2
Authors: Aziz Moammir H. , Wheeler Deric L. , Bhamb Bhushan , Verma Ajit K.
Published: January 2006

Protein kinase C δ (PKCδ), a Ca2+-independent, phospholipid-dependent serine/threonine kinase, is among the novel PKCs (δ, ε, and η) expressed in mouse epidermis. We reported that FVB/N transgenic mice that overexpress (∼8-fold) PKCδ protein in basal epidermal cells and cells of the hair follicle are resistant to the development of both skin papillomas and squamous cell carcinoma (SCC) elicited by 7,12-dimethylbenz(a)anthracene initiation and 12-O-tetradecanoylphorbol-13-acetate (TPA) promotion protocol. We now present that PKCδ overexpression in transgenic mice failed to suppress the induction of SCC developed by repeated exposures to UV radiation (UVR), the environmental carcinogen linked to the development of human SCC. Both TPA and UVR treatment of wild-type mice (a) increased the expression of proliferating cell nuclear antigen (PCNA) and apoptosis; (b) stimulated the expression of cytokines tumor necrosis factor-α (TNF-α), granulocyte macrophage colony-stimulating factor (GM-CSF), and granulocyte CSF (G-CSF); and (c) increased cyclooxygenase-2 (COX-2) expression and expression of phosphorylated Akt (p-Akt), p38, extracellular signal-regulated kinase-1 (ERK1), and ERK2. PKCδ overexpression in transgenic mice enhanced TPA-induced but not UVR-induced apoptosis and suppressed TPA-stimulated but not UVR-stimulated levels of cell PCNA, cytokines (TNF-α, G-CSF, and GM-CSF), and the expression of COX-2, p-Akt, and p38. The results indicate that UVR-mediated signal transduction pathway to the induction of SCC does not seem to be sensitive to PKCδ overexpression. The proapoptotic activity of PKCδ coupled with its ability to suppress TPA-induced expression of proinflammatory cytokines, COX-2 expression, and the phosphorylation of Akt and p38 may play roles in the suppression of TPA-promoted development of SCC. (Cancer Res 2006; 66(2): 713-22)
Oncogenic BRAF Is Required for Tumor Growth and Maintenance in Melanoma Models
Authors: Hoeflich Klaus P. , Gray Daniel C. , Eby Michael T. , Tien Janet Y. , Wong Leo , Bower Janeko , Gogineni Alvin , Zha Jiping , Cole Mary J. , Stern Howard M. , Murray Lesley J. , Davis David P. , Seshagiri Somasekar
Published: January 2006

The usual paradigm for developing kinase inhibitors in oncology is to use a high-affinity proof-of-concept inhibitor with acceptable metabolic properties for key target validation experiments. This approach requires substantial medicinal chemistry and can be confounded by drug toxicity and off-target activities of the test molecule. As a better alternative, we have developed inducible short-hairpin RNA xenograft models to examine the in vivo efficacy of inhibiting oncogenic BRAF. Our results show that tumor regression resulting from BRAF suppression is inducible, reversible, and tightly regulated in these models. Analysis of regressing tumors showed the primary mechanism of action for BRAF to be increased tumor cell proliferation and survival. In a metastatic melanoma model, conditional BRAF suppression slowed systemic tumor growth as determined by in vivo bioluminescence imaging. Taken together, gain-of-function BRAF signaling is strongly associated with in vivo tumorigenicity, confirming BRAF as an important target for small-molecule and RNA interference–based therapeutics. (Cancer Res 2006; 66(2): 999-1006)
Differential Gene Expression Analysis Reveals Generation of an Autocrine Loop by a Mutant Epidermal Growth Factor Receptor in Glioma Cells
Authors: Ramnarain Deepti B. , Park Seongmi , Lee Diana Y. , Hatanpaa Kimmo J. , Scoggin Shane O. , Otu Hasan , Libermann Towia A. , Raisanen Jack M. , Ashfaq Raheela , Wong Eric T. , Wu Julian , Elliott Robert , Habib Amyn A.
Published: January 2006

The epidermal growth factor receptor (EGFR) gene is commonly amplified and rearranged in glioblastoma multiforme leading to overexpression of wild-type and mutant EGFRs. Expression of wild-type EGFR ligands, such as transforming growth factor-α (TGF-α) or heparin-binding EGF (HB-EGF), is also often increased in gliomas resulting in an autocrine loop that contributes to the growth autonomy of glioma cells. Glioblastoma multiformes express a characteristic EGFR mutant (EGFRvIII, de 2-7) that does not bind ligand, signals constitutively, and is more tumorigenic than the wild-type receptor. However, the downstream signals that mediate this increased tumorigenicity are not well understood. We hypothesized that signals induced specifically by EGFRvIII and not the wild-type receptor are more likely to mediate its increased tumorigenic activity and examined the gene expression profiles resulting from inducible expression of comparable levels of either wild-type EGFR or EGFRvIII in a U251-MG glioma cell line. Expression of EGFRvIII resulted in specific up-regulation of a small group of genes. Remarkably, all these genes, which include TGFA, HB-EGF, EPHA2, IL8, MAP4K4, FOSL1, EMP1, and DUSP6, influence signaling pathways known to play a key role in oncogenesis and function in interconnected networks. Increased expression of EGFRvIII-induced genes was validated by real-time PCR. The mutant receptor does not bind ligand, and EGFRvIII-induced expression of TGF-α and HB-EGF suggests that EGFRvIII plays a role in generating an autocrine loop using the wild-type EGFR in glioma. It also raises the possibility that EGFRvIII may signal, at least in part, through the wild-type receptor. Indeed, we show that inhibiting the activity of HB-EGF, a potent mitogen, with neutralizing antibodies reduces cell proliferation induced by expression of EGFRvIII. This suggests that the EGFRvIII-HB-EGF-wild-type EGFR autocrine loop plays an important role in signal transduction by EGFRvIII in glioma cells. We also show by immunohistochemistry that HB-EGF expression correlates with the presence of EGFRvIII in glioblastoma multiforme. Thus, our study provides a new insight into oncogenic signaling by EGFRvIII and improves our understanding of how autocrine loops are generated in glioma. (Cancer Res 2006; 66(2): 867-74)
Vaccine with β-Defensin 2–Transduced Leukemic Cells Activates Innate and Adaptive Immunity to Elicit Potent Antileukemia Responses
Authors: Ma Xiao-Tong , Xu Bin , An Li-Li , Dong Cheng-Ya , Lin Yong-Min , Shi Yang , Wu Ke-Fu
Published: January 2006

Murine β-defensin 2 (MBD2) is a small antimicrobial peptide of the innate immune system. Recent study showed that MBD2 could not only recruit immature dendritic cells but also activate them by Toll-like receptor 4 and thus may provide a critical link between the innate immune system and the adaptive immune response. In this report, we examined the antileukemia activity of MBD2 in a murine model of acute lymphoid leukemia (ALL) L1210. L1210 cells were engineered to secrete biologically functional MBD2. MBD2-modified L1210 (L1210-MBD2) showed significantly reduced leukemogenecity, resulting in a 80% rate of complete leukemia rejection. Inoculation of mice with L1210-MBD2 induced enhanced CTL and natural killer (NK) activity and augmented interleukin-12 and IFN-γ production. All the recovered mice from the inoculation showed a protective immunity to the following challenge with parental L1210 cells and generate leukemia-specific memory CTL. Vaccines with irradiated L1210-MBD2 cells could cure 50% leukemia-bearing mice. Depletion of CD8+ T cells but not CD4+ T cells completely abrogated the antileukemia activity of MBD2. Interestingly, NK cells were also required for the MBD2-mediated antileukemia response, although ALL generally display a high degree of resistance to NK-mediated lysis. Our results suggest that MBD2 can activate both innate and adaptive immunity to generate potent antileukemia response, and MBD2 immunotherapy warrants further evaluation as a potential treatment for ALL. (Cancer Res 2006; 66(2): 1169-76)
Expression of a Fibroblast Growth Factor–Binding Protein during the Development of Adenocarcinoma of the Pancreas and Colon
Authors: Tassi Elena , Henke Ralf T. , Bowden Emma T. , Swift Matthew R. , Kodack David P. , Kuo Angera H. , Maitra Anirban , Wellstein Anton
Published: January 2006

The activity of growth factors is crucial for tumor progression. We previously characterized a secreted fibroblast growth factor–binding protein (FGF-BP1) as a chaperone molecule, which enhances the biological functions of FGFs by releasing FGFs from the extracellular matrix. Here, we characterize the frequency and pattern of FGF-BP1 expression during the malignant progression of pancreas and colorectal carcinoma. For this, we generated monoclonal antibodies that detect FGF-BP1 protein in formalin-fixed, paraffin-embedded tissues and applied in situ hybridization to detect FGF-BP1 mRNA in adjacent tissue sections. FGF-BP1 protein and mRNA were found up-regulated (>70% positive) in parallel (r = 0.70, P < 0.0001) in colon adenoma (n = 9) as well as primary (n = 46) and metastatic (n = 71) colorectal cancers relative to normal colon epithelia (all P < 0.0001, versus normal). Similarly, pancreatitis (n = 17), pancreatic intraepithelial neoplasia (n = 80), and pancreatic adenocarcinoma (n = 67) showed a significant up-regulation of FGF-BP1 compared with normal pancreas (n = 42; all P < 0.0001, relative to normal). Furthermore, the biological activity of FGF-BP1 is neutralized by one of the antibodies, suggesting the potential for antibody-based therapeutic targeting. We propose that the up-regulation of the secreted FGF-BP1 protein during initiation of pancreas and colon neoplasia could make this protein a possible serum marker indicating the presence of high-risk premalignant lesions. (Cancer Res 2006; 66(2): 1191-8)
TC1 (C8orf4) Enhances the Wnt/β-Catenin Pathway by Relieving Antagonistic Activity of Chibby
Authors: Jung Yusun , Bang Seunghyun , Choi Kyungho , Kim Eunsoon , Kim Youngmi , Kim Jungtae , Park Juhee , Koo Hyunlyoung , Moon Randall T. , Song Kyuyoung , Lee Inchul
Published: January 2006

The Wnt/β-catenin pathway has been implicated in human cancers. Here, we show that TC1 (C8orf4), a small protein present in vertebrates, functions as a positive regulator of the pathway. TC1 interacts with Chibby (Cby) and thereby enhances the signaling pathway by relieving the antagonistic function of Cby on the β-catenin–mediated transcription. Upon coexpression in mammalian cells, TC1 redistributes from nucleolus to nuclear speckles, where it colocalizes with Cby. TC1 up-regulates the expression of β-catenin target genes that are implicated in invasiveness and aggressive behavior of cancers, such as metalloproteinases, laminin γ2, and others. Our data indicate that TC1 is a novel upstream regulator of the Wnt/β-catenin pathway that enhances aggressive behavior of cancers. (Cancer Res 2006; 66(2): 723-8)
HIV-1 Vpr Induces DNA Double-Strand Breaks
Authors: Tachiwana Hiroaki , Shimura Mari , Nakai-Murakami Chikako , Tokunaga Kenzo , Takizawa Yoshimasa , Sata Tetsutaro , Kurumizaka Hitoshi , Ishizaka Yukihito
Published: January 2006

Recent observations imply that HIV-1 infection induces chromosomal DNA damage responses. However, the precise molecular mechanism and biological relevance are not fully understood. Here, we report that HIV-1 infection causes double-strand breaks in chromosomal DNA. We further found that Vpr, an accessory gene product of HIV-1, is a major factor responsible for HIV-1–induced double-strand breaks. The purified Vpr protein promotes double-strand breaks when incubated with isolated nuclei, although it does not exhibit endonuclease activity in vitro. A carboxyl-terminally truncated Vpr mutant that is defective in DNA-binding activity is less capable of Vpr-dependent double-strand break formation in isolated nuclei. The data suggest that double-strand breaks induced by Vpr depend on its DNA-binding activity and that Vpr may recruit unknown nuclear factor(s) with positive endonuclease activity to chromosomal DNA. This is the first direct evidence that Vpr induces double-strand breaks in HIV-1–infected cells. We discuss the possible roles of Vpr-induced DNA damage in HIV-1 infection and the involvement of Vpr in further acquired immunodeficiency syndrome–related tumor development. (Cancer Res 2006; 66(2): 627-31)
Comparison of Metabolic Pathways between Cancer Cells and Stromal Cells in Colorectal Carcinomas: a Metabolic Survival Role for Tumor-Associated Stroma
Authors: Koukourakis Michael I. , Giatromanolaki Alexandra , Harris Adrian L. , Sivridis Efthimios
Published: January 2006

Understanding tumor metabolism is important for the development of anticancer therapies. Immunohistochemical evaluation of colorectal adenocarcinomas showed that cancer cells share common enzyme/transporter activities suggestive of an anaerobic metabolism [high lactate dehydrogenase 5 (LDH5)/hypoxia-inducible factor αs (HIFαs)] with high ability for glucose absorption and lactate extrusion [high glucose transporter 1 (GLUT1)/monocarboxylate transporter (MCT1)]. The tumor-associated fibroblasts expressed proteins involved in lactate absorption (high MCT1/MCT2), lactate oxidation (high LDH1 and low HIFαs/LDH5), and reduced glucose absorption (low GLUT1). The expression profile of the tumor-associated endothelium indicated aerobic metabolism (high LDH1 and low HIFαs/LDH5), high glucose absorption (high GLUT1), and resistance to lactate intake (lack of MCT1). It is suggested that the newly formed stroma and vasculature express complementary metabolic pathways, buffering and recycling products of anaerobic metabolism to sustain cancer cell survival. Tumors survive and grow because they are capable of organizing the regional fibroblasts and endothelial cells into a harmoniously collaborating metabolic domain. (Cancer Res 2006; 66(2): 632-7)
Radiation-Induced Changes in Gene Expression Involve Recruitment of Existing Messenger RNAs to and away from Polysomes
Authors: Lü Xing , de la Peña Lorena , Barker Christopher , Camphausen Kevin , Tofilon Philip J.
Published: January 2006

Although ionizing radiation has been shown to influence gene transcription, little is known about the effects of radiation on gene translational efficiency. To obtain a genome-wide perspective of the effects of radiation on gene translation, microarray analysis was done on polysome-bound RNA isolated from irradiated human brain tumor cells; to allow for a comparison with the effects of radiation on transcription, microarray analysis was also done using total RNA. The number of genes whose translational activity was modified by radiation was ∼10-fold greater than those whose transcription was affected. The radiation-induced change in a gene's translational activity was shown to involve the recruitment of existing mRNAs to and away from polysomes. Moreover, the change in a gene's translational activity after irradiation correlated with changes in the level of its corresponding protein. These data suggest that radiation modifies gene expression primarily at the level of translation. In contrast to transcriptional changes, there was considerable overlap in the genes affected at the translational level among brain tumor cell lines and normal astrocytes. Thus, the radiation-induced translational control of a subset of mRNAs seems to be a fundamental component of cellular radioresponse. (Cancer Res 2006; 66(2): 1052-61)
CpG Island Methylation and Expression of the Secreted Frizzled-Related Protein Gene Family in Chronic Lymphocytic Leukemia
Authors: Liu Te-Hui , Raval Aparna , Chen Shih-Shih , Matkovic Jennifer J. , Byrd John C. , Plass Christoph
Published: January 2006

B-cell chronic lymphocytic leukemia (CLL) is characterized by a clonal accumulation of mature neoplastic B cells indicating disruption of apoptosis. Restriction Landmark Genome Scanning was done to identify novel target genes silenced by CpG island methylation in CLL. Secreted frizzled-related protein 4 (SFRP4), a negative regulator of the Wnt signaling pathway, was found to be frequently methylated in CLL samples. Wnt signaling has been shown to control normal apoptotic behavior and is required for normal B-cell development whereas aberrant activation of this pathway has been observed in CLL. We show aberrant DNA methylation and silencing of SFRP4, as well as of additional SFRP family members, in primary CLL samples. Induction of their expression in a dose-dependent manner following treatment with a demethylating agent, 5-aza-2′-deoxycytidine, was shown. Of the five SFRP family members studied in detail, SFRP1 was hypermethylated and down-regulated in all CLL patient samples studied, suggesting that this epigenetic event is a critical step during leukemogenesis. Our results suggest that silencing of SFRPs by CpG island methylation is one possible mechanism contributing to aberrant activation of Wnt signaling pathway in CLL. (Cancer Res 2006; (66)2: 653-8)
The Role of Protein Kinase C-Alpha in Hematologic Malignancies
Authors: Lahn Michael , Sundell Karen , Köhler Gabriele
Published: January 2006

In recent years advances in histopathological and molecular understanding of hematologic malignancies have led to the development of drugs which selectively target proteins associated with hematologic tumorigenesis. One such targeted agent is the antisense oligonucleotide aprinocarsen, which specifically inhibits the signaling protein, protein kinase C-α (PKC-α). Although PKC-α has been associated with tumorigenesis, its role and expression levels in patients with hematologic malignancies are not well understood. We here review studies investigating the expression and role of PKC-α in hematologic malignancies. Such a review may offer new insights on how to develop strategies in identifying patients that might best benefit from PKC-α inhibition.
High-Dose Idarubicin, Busulphan and Melphalan for Autologous Stem Cell Transplantation in Multiple Myeloma Responsive to DAV Chemotherapy: Comparison with a Historical Control
Authors: Capria Saveria , Petrucci Maria Teresa , Pulsoni Alessandro , Ribersani Michela , Baldacci Erminia , de Propris Maria Stefania , Meloni Giovanna
Published: January 2006

Since 1997, 32 newly diagnosed multiple myeloma patients responsive to DAV chemotherapy were autografted with idarubicin-intensified busulphan-melphalan (ida-bu-mel). Main endpoints of the study were transplant-related toxicity, overall survival (OS) and progression-free survival (PFS). The results were compared with a historical control group of 38 patients treated with the ‘standard’ bu-mel regimen. Concerning time to engraftment, no significant difference was observed between the two groups, while toxicity was significantly higher in the intensive conditioning group, regarding grade IV mucositis, duration of profound neutropenia, incidence of infections and platelet requirement. Five-year OS and PFS are 73 versus 78% and 37 versus 48% for the intensive and standard regimen, respectively (p value not significant). The ida-bu-mel schedule appears to be a feasible and effective regimen for newly diagnosed multiple myeloma patients; nevertheless, no apparent benefit in OS and PFS arises from the comparison with a historical control treated with standard bu-mel, which is better tolerated and at least equally effective.
Dose-Dense CHOP plus Rituximab (R-CHOP14) for the Treatment of Elderly Patients with High-Risk Diffuse Large B Cell Lymphoma: A Pilot Study
Authors: Rigacci Luigi , Nassi Luca , Alterini Renato , Carrai Valentina , Longo Giovanni , Bernardi Franco , Martini Varesco , Bosi Alberto
Published: January 2006

Background: Aggressive non-Hodgkin’s lymphomas (NHL) require intensive therapies which seemed impracticable in elderly patients. Dose reduction and therapy attenuation reduced treatment-related toxicity, but also decreased therapeutic efficacy. In elderly patients too, the achievement of complete remission is the most important prognostic factor affecting outcome. Therefore, we have treated elderly patients with a dose-intensified protocol. Aim of the study was to verify the feasibility of this scheme in a subset of patients with high-risk aggressive lymphomas. Methods: Between June 2002 and June 2004, 26 patients over the age of 60 years with a diagnosis of aggressive NHL and an intermediate-high or high International Prognostic Index were treated with biweekly CHOP plus rituximab with the support of granulocyte colony-stimulating factors (G-CSF). Results: Seventeen patients (65%) regularly kept the interval between cycles. Haematological and extrahaematological toxicities were moderate in all the patients. Twenty (77%) patients achieved complete remissions, 6 (23%) partial remissions with an overall response rate of 100%. After a median follow-up of 23 months, the overall survival was 79%; after a median follow-up of 17 months, the disease-free survival was 70%. Conclusion: These results confirm that a dose-dense CHOP programme can be administered safely and effectively in a subset of elderly patients with high-risk aggressive NHL. The addition of rituximab could increase the response rate without adding toxicity.
Recombinant Urate Oxidase (Rasburicase) for the Prevention and Treatment of Tumor Lysis Syndrome in Patients with Hematologic Malignancies
Authors: Wang Lin-Yen , Shih Lee-Yung , Chang Hung , Jou Shiann-Tarng , Lin Kai-Hsin , Yeh Ting-Chi , Lin Sheng-Fung , Liang Der-Cherng
Published: January 2006

In this multicenter, nonrandomized, open-label clinical trial conducted from July 2003 to July 2004, recombinant urate oxidase (rasburicase) was administered to patients at risk for tumor lysis syndrome before or during the initiation of chemotherapy. Forty-five patients were enrolled, including 18 children (10 with acute lymphoblastic leukemia, 6 with high-grade lymphoma, and 2 with acute myeloid leukemia) and 27 adults (8 with acute lymphoblastic leukemia, 4 with high-grade lymphoma, 9 with multiple myeloma, and 6 with acute myeloid leukemia). The age ranged from 3 to 98 years, with a median age of 7 years in children and 59.3 years in adults. There were 14 males and 4 females in the pediatric group and 18 males and 9 females in the adult group. Rasburicase 0.2 mg/kg was administered intravenously once a day for 2–6 days, for a median of 3 days in children and of 4 days in adults. After 3 days of treatment, the median uric acid levels in the 18 children decreased from 10.5 mg/dl (range 8–18.6) to 0.5 mg/dl (range 0.0–1.7). Similarly, in the 27 adults, the median levels decreased from 10.8 mg/dl (range 8–24.4) to 0.5 mg/dl (range 0.0–1.6). No significant changes were observed in serum potassium, calcium, and phosphorus concentrations. None of the patients required dialysis for acute renal failure. Rasburicase was very well tolerated, with only 1 adult having grade 1 vomiting. We conclude that rasburicase is safe and highly effective for preventing the complications of tumor lysis syndrome in patients with hematologic malignancies.
Splenectomy for Chronic Idiopathic Thrombocytopenic Purpura in Children: A Single Center Study in China
Authors: Wang Tingting , Xu Maoqiang , Ji Linxiang , Yang Renchi
Published: January 2006

The management of chronic and refractory idiopathic thrombocytopenic purpura (ITP) in children is controversial. We conducted a retrospective review of our single center experience in China between 1990 and 2003 with splenectomy for chronic ITP in children in order to determine the initial and long-term hematological response, morbidity, mortality, predictors of response to splenectomy and the therapy in children who failed splenectomy. Of 65 children analyzed, the overall immediate clinical response to splenectomy was 89.2%. The median postsplenectomy follow-up time was 52 months (8–124). During follow-up, 9 children (13.8%) relapsed within a median time of 6 months (2–58). The overall morbidity was 1.5% and perioperative mortality was zero. During follow-up, 1 child died of intracranial hemorrhage (ICH) and 1 died of overwhelming postsplenectomy infection (OPSI). The platelet count at day 7 after splenectomy was a predictor of a sustained response to splenectomy but no preoperative parameters were predictors of the response to splenectomy. Of the 15 children who failed splenectomy, excluding the one who died of ICH, only 2 children intermittently required corticosteroids and IVIG. Splenectomy is a potential therapy to provide long-term control of disease in children with chronic ITP and is associated with low morbidity and mortality. The risk of fulminant sepsis remains an omnipresent concern. Antipneumococcal vaccination and antibiotic prophylaxis should be recommended and children should receive timely and adequate antibiotics for bacteria infection to lessen the problem of OPSI.
Histone Deacetylase Inhibitor Depsipeptide (FK228) Induces Apoptosis in Leukemic Cells by Facilitating Mitochondrial Translocation of Bax, Which Is Enhanced by the Proteasome Inhibitor Bortezomib
Authors: Sutheesophon Krittaya , Kobayashi Yukiko , Takatoku Masa-aki , Ozawa Keiya , Kano Yasuhiko , Ishii Hideshi , Furukawa Yusuke
Published: January 2006

Histone deacetylase (HDAC) inhibitors are promising candidates for molecular-targeted therapy for leukemia. In this study, we investigated the mechanisms of cytotoxic effects of depsipeptide (FK228), one of the most effective HDAC inhibitors against leukemia, using human myeloid leukemic cell lines HL-60 and K562. We found that FK228 activated caspase-9 and a subsequent caspase cascade by perturbing the mitochondrial membrane to release cytochrome c, which was almost completely blocked by overexpression of Bcl-2. The mitochondrial damage was caused by the translocation of Bax but not other pro-apoptotic Bcl-2 family proteins to the mitochondria. FK228 did not affect the interaction between Bax and Bax adaptor proteins such as 14-3-3Θ and Ku70. FK228-induced apoptosis and mitochondrial translocation of Bax were markedly enhanced by the proteasome inhibitor bortezomib. The synergistic action of FK228 and bortezomib was at least partly mediated through conformational changes in Bax, which facilitate its translocation to the mitochondria. These results suggest that the combination of HDAC inhibitors and proteasome inhibitors is useful in the treatment of leukemia especially in the context of molecular-targeted therapy. The status of Bcl-2 and Bax may influence the sensitivity of tumors to this combination and thus can be a target of further therapeutic intervention.
Diastolic Dysfunction and Pulmonary Hypertension in Sickle Cell Anemia: Is There a Role for L-Carnitine Treatment?
Authors: El-Beshlawy A. , Abd El Raouf E. , Mostafa F. , Talaat M. , Isma’eel H. , Aoun E. , Hoffbrand A.V. , Taher A.
Published: January 2006

Clinical manifestations of cardiovascular abnormalities in patients with sickle cell (SC) anemia are well documented. Many variables were assessed in our study before and after administration of L-carnitine to randomly selected 37 SC disease (SCD) children for a period of 6 months. Variables such as weight, height, serum ferritin levels, units of blood transfused and the number of veno-occlusive crises all showed significant improvement after the 6 months of therapy with L-carnitine. Our study also showed that cardiac diastolic function and pulmonary hypertention are common in pediatric SCD patients. These two disorders showed some improvement after L-carnitine administration. Therefore, L-carnitine deserves a rigorous large-scale randomized clinical trial to evaluate its potential benefits as treatment for SCD patients with cardiac complications.
Trisomy 8 in Prefibrotic Early Stages of Chronic Idiopathic Myelofibrosis: A Fluorescence in situ Study of Bone Marrow Biopsies
Authors: Thiele J. , Varus E. , Kvasnicka H.M. , Wickenhauser C.
Published: January 2006

Repeatedly performed bone marrow biopsies were studied in 30 patients with chronic idiopathic myelofibrosis (CIMF) by fluorescence in situ hybridization to detect and quantify trisomy 8 anomaly during the evolution of disease. For the establishment of threshold values we used negative and positive control specimens. At least 500 cells were evaluated in each specimen and only nuclei with three distinctive signals were regarded as positive. According to the controls, 27 patients revealed false-positive signals ranging from 0 to 1.2% (0.88 ± 1.12). On the other hand, 3 patients showed an incidence of more than 6.5% (up to 10.1%) in the initial prefibrotic as well as advanced fibro-osteosclerotic stages of CIMF. In conclusion, trisomy 8 has been demonstrated already in the prodromal stages of CIMF and therefore is not limited to classical fibro-osteosclerotic manifestations.
Development of Thalassaemic Iron Overload Cardiomyopathy despite Low Liver Iron Levels and Meticulous Compliance to Desferrioxamine
Authors: Anderson Lisa J. , Westwood Mark A. , Prescott Emma , Walker J. Malcolm , Pennell Dudley J. , Wonke Beatrix
Published: January 2006

It is believed that myocardial iron deposition and the resultant cardiomyopathy only occur in the presence of severe liver iron overload. Using cardiovascular magnetic resonance, it is now possible to assess myocardial and liver iron levels as well as cardiac function in the same scan, allowing this supposition to be examined. We describe a patient with progressive myocardial iron deposition and the development of early iron overload cardiomyopathy despite excellent compliance to standard subcutaneous desferrioxamine, minimal liver iron and well-controlled serum ferritin levels. These indirect markers remained far below the thresholds conventionally believed to be associated with increased cardiac risk.
Continuous Complete Hematological and Cytogenetic Remission with Molecular Minimal Residual Disease 9 Years after Discontinuation of Interferon-α in a Patient with Philadelphia Chromosome-Positive Chronic Myeloid Leukemia
Authors: Verbeek W. , König H. , Boehm J. , Kohl D. , Lange C. , Heuer T. , Scheibenbogen C. , Reis H.-E. , Hochhaus A. , Graeven U.
Published: January 2006

Interferon-α has been used as standard therapy for patients with Philadelphia-positive chronic myeloid leukemia (CML) for more than 20 years. Recently randomized trials have shown a superiority of the tyrosine kinase inhibitor imatinib in respect to its efficacy to induce complete hematological and cytogenetic remissions and more importantly in overall survival. Although follow-up is much shorter for imatinib than for interferon-α, this data changed the treatment algorithms in this disease. At the end of the era of interferon-α as a single-drug first-line treatment for most patients we present a case report which exemplifies a rare but exciting property of interferon-α in CML: the induction of complete hematological and cytogenetic remissions which can persist over years after discontinuation of the drug. Hence, the enrollment of CML patients in clinical trials which explore a combination treatment of imatinib and interferon-α is warranted.
Fulminant Vasculitis: A Rare Fatal Complication of Lymphoma
Authors: Leshem Eyal , Davidovitz Yaron , Meltzer Eyal , Fefer Paul , Ofek Efrat , Sidi Yechezkel
Published: January 2006

Vasculitis is rarely associated with lymphoma; however, most cases associated with lymphoma are cutaneous. Systemic vasculitis in association with lymphoma is usually an indolent and non-fatal complication. Two patients presented to our department with fulminant vasculitis with a fatal course and were later diagnosed with lymphoma. A search of the literature for systemic fulminant vasculitis in association with lymphoma disclosed eight case reports. We suggest that lymphoma should be considered as a possible etiology in patients with fulminant systemic vasculitis. The therapeutic implications of such an association are discussed.
Protein-Tyrosine Phosphorylation in Bacillus subtilis
Authors: Mijakovic Ivan , Petranovic Dina , Bottini Nunzio , Deutscher Josef , Ruhdal Jensen Peter
Published: January 2006

In recent years bacterial protein-tyrosine kinases have been found to phosphorylate a growing number of protein substrates, including RNA polymerase sigma factors, UDP-glucose dehydrogenases and single-stranded DNA-binding proteins. The activity of these protein substrates was affected by tyrosine phosphorylation, indicating that this post-translational modification could regulate physiological processes ranging from stress response and exopolysaccharide synthesis to DNA metabolism. Some interesting work in this field was done in Bacillus subtilis, and we here present the current state of knowledge on protein-tyrosine phosphorylation in this gram-positive model organism. With its two kinases, two kinase modulators, three phosphatases and at least four different tyrosine-phosphorylated substrates, B. subtilis is the bacterium with the highest number of presently known participants in the global network of protein-tyrosine phosphorylation. We discuss the approaches currently used to chart this network: ranging from studies of substrate specificity and the physiological role of tyrosine phosphorylation of individual enzymes to the global approaches at the level of systems biology.
Polyphasic Activity Patterns in Small Mammals
Authors: Halle Stefan
Published: January 2006

Cathemeral species are routinely active during the day, the night and at twilight. For the majority of species it is advantageous to specialize on the environmental conditions of a particular phase of the 24-hour day, so this rather uncommon type of activity must be a consequence of specific constraints. Good examples are the polyphasic activity patterns found in some small mammals. In shrews, with small body size and extremely high metabolic rate, polyphasic activity represents a simple short-term hunger cycle. In voles the short-term rhythm is triggered by an additional endogenous ultradian clock that interacts with the common circadian system, which probably is functionally related to endosymbiont digestion of cellulose-rich food. The activity bouts of individuals are synchronized on the population level to spread predation risk. As cathemeral species, voles are not specifically adapted to particular light conditions, but they are also not restricted to a particular activity phase. Therefore, the benefits from flexible responses in activity timing to environmental challenges may compensate for the disadvantages of not being specialized.
Eye Morphology in Cathemeral Lemurids and Other Mammals
Authors: Christopher Kirk E.
Published: January 2006

The visual systems of cathemeral mammals are subject to selection pressures that are not encountered by strictly diurnal or nocturnal species. In particular, the cathemeral eye and retina must be able to function effectively across a broad range of ambient light intensities. This paper provides a review of the current state of knowledge regarding the visual anatomy of cathemeral primates, and presents an analysis of the influence of cathemerality on eye morphology in the genusEulemur. Due to the mutual antagonism between most adaptations for increased visual acuity and sensitivity, cathemeral lemurs are expected to resemble other cathemeral mammals in having eye morphologies that are intermediate between those of diurnal and nocturnal close relatives. However, if lemurs only recently adopted cathemeral activity patterns, then cathemeral lemurids would be expected to demonstrate eye morphologies more comparable to those of nocturnal strepsirrhines. Both predictions were tested through a comparative study of relative cornea size in mammals. Intact eyes were collected from 147 specimens of 55 primate species, and relative corneal dimensions were compared to measurements taken from a large sample of non-primate mammals. These data reveal that the five extant species of the cathemeral genusEulemurhave relative cornea sizes intermediate between those of diurnal and nocturnal strepsirrhines. Moreover, allEulemurspecies have relative cornea sizes that are comparable to those of cathemeral non-primate mammals and significantly smaller than those of nocturnal mammals. These results suggest thatEulemurspecies resemble other cathemeral mammals in having eyes that are adapted to function under variable environmental light levels. These results also suggest that cathemerality is a relatively ancient adaptation inEulemurthat was present in the last common ancestor of the genus (ca. 8–12 MYA).
Why Be Diurnal? Or, Why Not Be Cathemeral?
Authors: Hill R.A.
Published: January 2006

As a behavioural strategy, cathemerality is thought to confer considerable advantages by allowing animals to extend activity flexibly into either the diurnal or nocturnal phase in response to the prevailing ecological conditions. Factors such as temperature, access to food sources and minimising the risk of predation are all thought to be important in promoting cathemerality, although previous studies have produced inconsistent results. This paper adopts a different approach by first asking whether an obligate diurnal species, the chacma baboon(Papio hamadryas ursinus), exhibits seasonal variation in behavioural flexibility in response to annual cycles of day length. While short day lengths are an important constraint on the activity of the baboons at De Hoop Nature Reserve, South Africa, long summer days permit considerable flexibility in thermoregulatory response, diet selection and patterns of habitat choice. Given that baboons adapt flexibly in response to a relaxation of time constraints, the question thus arises as to why diurnal and nocturnal primates do not adopt cathemeral activity patterns when time is constrained? For baboons, the costs of predation appear to prohibit exploitation of the nocturnal phase and it is likely that such constraints are true of most primates. It thus follows that Madagascar’s predatory environment must in some way permit or select for a cathemeral lifestyle. The importance of the predation by fossa(Cryptoprocta ferox)on the evolution of cathemerality is discussed.