bluuebunny/crossref_metadata_2025 huggingface dataset:
Cooperative Antitumor Effect of Multitargeted Kinase Inhibitor ZD6474 and Ionizing Radiation in Glioblastoma
Authors: Damiano Vincenzo , Melisi Davide , Bianco Cataldo , Raben David , Caputo Rosa , Fontanini Gabriella , Bianco Roberto , Ryan Anderson , Bianco A. Raffaele , De Placido Sabino , Ciardiello Fortunato , Tortora Giampaolo
Published: September 2005

Purpose: Glioblastoma multiforme is an aggressive disease in which vascular endothelial growth factor (VEGF) and the EGF receptor (EGFR) are implicated in tumor growth, relapse, and resistance to radiotherapy and chemotherapy. The VEGF receptors VEGFR-1 (flt-1) and VEGFR-2 (KDR), typically present on endothelial cells, have also been identified in human glioblastoma tissues and cell lines. In addition, EGFR is dysregulated in the majority of human glioblastomas and EGFR overexpression correlates with shorter survival. We have investigated the antitumor and antiangiogenic effect of ZD6474, an inhibitor of both VEGFR and EGFR signaling as a single agent and in combination with ionizing radiation.

Experimental Design: We have used ZD6474 and/or ionizing radiation in human glioblastoma cell lines D54 and U251 in vitro and in nude mice bearing established xenografts. The effects of treatment on tumor blood vessels and protein expression were evaluated by Western blot and immunohistochemistry.

Results: As single agents, ionizing radiation and ZD6474 caused a dose-dependent inhibition of soft agar growth in D54 and U251 cell lines, whereas a cooperative effect was obtained in combination. Treatment of mice bearing D54 xenografts with either ZD6474 or radiotherapy alone caused tumor growth inhibition that was reversible upon treatment cessation. A cooperative and long-lasting inhibition of tumor growth was obtained with ZD6474 in combination with concomitant radiotherapy. The antiproliferative effect was accompanied by inhibition of VEGF protein expression and inhibition of angiogenesis as measured by vessel counting.

Conclusion: This study shows the antitumor activity of ZD6474 in combination with ionizing radiation in glioblastoma both in vitro and in vivo, and provides a scientific rationale to evaluate ZD6474 alone or in combination with radiotherapy in patients affected by this disease.
High Expression of a New Marker PCA-1 in Human Prostate Carcinoma
Authors: Konishi Noboru , Nakamura Mitsutoshi , Ishida Eiwa , Shimada Keiji , Mitsui Eika , Yoshikawa Rintaro , Yamamoto Hiroshi , Tsujikawa Kazutake
Published: September 2005

Purpose: Identifying the genetic factors involved in prostate carcinogenesis is critical. Novel cancer-specific markers aid in early detection, in differentiating between cancer and nonmalignant disorders, and in monitoring clinical of prostate disease. We therefore examined differential gene displays in an attempt to identify genes that may be involved in prostate carcinogenesis.

Experimental Design: Applying fluorescent differential display analysis to human prostate carcinomas, we have identified and cloned several cDNA transcripts. Antisera were raised against synthetic peptides and used in Western blot and immunohistochemical analyses. The mRNAs were also analyzed by real-time reverse transcription-PCR. For functional analysis, we assessed methylmethane sulfonate (MMS)–induced toxicity in COS-7 cells after cDNA transfection.

Results: We identified a gene, designated prostate cancer antigen-1 (pca-1), which shows high mRNA expression in prostate carcinoma. Database analysis of the deduced amino acid sequence of PCA-1 indicated high similarity to Escherichia coli AlkB, a DNA alkylation damage repair enzyme. By immunohistochemical analysis, PCA-1 was expressed in a high number of both prostate carcinoma samples and in the atypical cells within high-grade prostatic intraepithelial neoplasias but not in benign prostatic hyperplasia or normal adjacent tissues. PCA-1-transfected COS-7 cells further showed resistance against MMS-induced cell death.

Conclusions: These findings suggest that PCA-1 could be a useful diagnostic marker. Furthermore, because this human counterpart of AlkB exhibits a protective function against alkylation damage in mammalian cells, PCA-1 may also serve as a therapeutic target molecule for prostate cancer.
Estrogen Receptor α and β are Prognostic Factors in Non–Small Cell Lung Cancer
Authors: Kawai Hideki , Ishii Akira , Washiya Kiyotada , Konno Toshiko , Kon Hiroto , Yamaya Chiharu , Ono Iwao , Minamiya Yoshihiro , Ogawa Junichi
Published: September 2005

Purpose: Estrogen receptor-α (ER-α) and -β (ER-β) play important roles in the carcinogenesis of breast tumors. Similarly, there have been several reports of ER expression in lung cancers, but the results have not been consistent, and the receptors' prognostic value remains unclear. Our goal was to investigate ER expression in non–small cell lung cancer (NSCLC) and to assess whether their expression correlates with prognosis.

Experimental Design: ER expression was examined using immunohistochemical methods with sections from 132 resected NSCLC specimens. Kaplan-Meier survival curves were analyzed to determine the significance of ER expression in the prognosis of NSCLC patients.

Results: ER-α was detected in the cytoplasm of 73% of the specimens analyzed, whereas ER-β was detected in the nucleus of 51%. ER-α expression correlated with poorer overall survival (P<0.001), as did the absence of ER-β expression (P = 0.048). Likewise, at histopathologic stage I, ER-α expression (P = 0.028) or the absence of ER-β (P = 0.037) correlated with a poorer prognosis, and ER-α(+)ER-β(−) patients had a significantly worse prognosis than ER-α(−)ER-β(+) patients (P = 0.00007). Multivariate Cox regression analysis revealed the absence of ER-β to be an independent factor predictive of poor disease outcome (hazard ratio, 1.9; 95% confidence interval, 1.1-3.4; P = 0.0264).

Conclusions: ER-α expression and the absence of ER-β expression are associated with a poorer prognosis among NSCLC patients. In particular, the absence of ER-β could serve as a marker identifying patients at high risk even at an early clinical stage.
Pseudolaric Acid B, a Novel Microtubule-Destabilizing Agent That Circumvents Multidrug Resistance Phenotype and Exhibits Antitumor Activity In vivo
Authors: Wong Vincent K.W. , Chiu Pauline , Chung Stephen S.M. , Chow Larry M.C. , Zhao Yun-Zhe , Yang Burton B. , Ko Ben C.B.
Published: September 2005

Purpose: Pseudolaric acid B (PAB) is the major bioactive constituent in the root bark of Pseudolarix kaempferi that has been used as an antifungal remedy in traditional Chinese medicine. Previous studies showed that PAB exhibited substantial cytotoxicity. The aims of this study were to elucidate the molecular target of PAB, to examine its mechanism of action, and to evaluate the efficacy of this compound in vivo.

Experimental Design: The effect of PAB on cell growth inhibition toward a panel of cancer cell lines was assayed. Cell cycle analysis, Western blotting, immunocytochemistry, and apoptosis analysis were carried out to examine the mechanism of action. Tubulin polymerization assays were conducted to examine the interaction between PAB and tubulin. A P-glycoprotein–overexpressing cell line was used to evaluate the efficacy of PAB toward multidrug-resistant phenotypes. In vivo efficacy of PAB was evaluated by the murine xenograft model.

Results: PAB induces cell cycle arrest at G2-M transition, leading to apoptosis. The drug disrupts cellular microtubule networks and inhibits the formation of mitotic spindles. Polymerization of purified bovine brain tubulin was dose-dependently inhibited by PAB. Furthermore, PAB circumvents the multidrug resistance mechanism, displaying notable potency also in P-glycoprotein–overexpressing cells. Finally, we showed that PAB is effective in inhibiting tumor growth in vivo.

Conclusions: We identified the microtubules as the molecular target of PAB. Furthermore, we showed that PAB circumvents P-glycoprotein overexpression-induced drug resistance and is effective in inhibiting tumor growth in vivo. Our work will facilitate the future development of PAB as a cancer therapeutic.
A Multicenter Phase II Trial of Thalidomide and Celecoxib for Patients with Relapsed and Refractory Multiple Myeloma
Authors: Prince H Miles , Mileshkin Linda , Roberts Andrew , Ganju Vinod , Underhill Craig , Catalano John , Bell Richard , Seymour John F. , Westerman David , Simmons Paul J. , Lillie Kate , Milner Alvin D. , Iulio Juliana Di , Zeldis Jerome B. , Ramsay Robert
Published: September 2005

Preclinical data indicates that cyclooxygenase-2 (COX-2) inhibition impairs plasma cell growth and potentially synergizes with thalidomide. We performed a trial in previously treated patients with myeloma using thalidomide up to a maximum dose of 800 mg/d with celecoxib (400 mg bid). Outcomes were compared with a prior trial of thalidomide. Sixty-six patients with median age of 67 (range, 43-85) received a median dose of thalidomide and celecoxib of 400 and 800 mg/d, respectively, with median durations of treatment of 27 and 13 weeks, respectively. The most common toxicities associated with premature discontinuation of celecoxib (n = 30 of 53, 57%) were fluid retention and deterioration of renal function. Overall response rate (RR) was 42% and with 20 months median follow-up; the actuarial median progression-free survival and overall survival were 6.8 and 21.4 months, respectively. Unlike our prior study, age >65 years was not predictive of inferior RR due to improvement in RR in older patients with the combination (37% versus 15%, P = 0.08). The RR was superior in patients who received a total dose of celecoxib exceeding 40 g in the first 8 weeks of therapy (62% versus 30%, P = 0.021). Progression-free survival and overall survival were also improved. Other predictors for inferior progression-free survival were age >65 years (P = 0.016) and elevated β2-microglobulin (P = 0.017). This study provides evidence that the addition of high-dose celecoxib adds to the antimyeloma activity of thalidomide but this comes with unacceptable toxicity. Future studies should use newer COX-2 inhibitors with thalidomide, or their respective derivatives.
Expression of Autocrine Motility Factor Correlates with the Angiogenic Phenotype of and Poor Prognosis for Human Gastric Cancer
Authors: Gong Weida , Jiang Yixing , Wang Liwei , Wei Daoyan , Yao James , Huang Suyun , Fang Shengyun , Xie Keping
Published: September 2005

Autocrine motility factor (AMF) is a cytokine known to regulate tumor cell motility. Recent studies have extended its role to many other aspects of cancer biology. In the present study, we examined the level of AMF expression and its relationship with vascular endothelial growth factor (VEGF) expression and the angiogenic phenotype in human gastric cancer and their effect on survival. The AMF and VEGF expression level and tumor microvessel density (MVD) status in archived tissue specimens from 86 resected gastric cancer cases were determined. AMF expression was significantly higher in both primary tumors and lymph node metastases than in adjacent normal gastric mucosa and normal gastric mucosa from individuals without gastric cancer. In univariate survival analyses, strong AMF expression was associated with inferior survival (P = 0.028). In a Cox proportional hazards model, strong AMF expression (P = 0.019) was independently prognostic of poor survival. Strong AMF expression in the lymph node metastases was associated with poor survival (P = 0.011). Furthermore, AMF expression in the primary tumors was directly correlated with VEGF expression and MVD status. We found the first clinical evidence that AMF expression is directly correlated with VEGF expression and MVD status and predicts clinical outcome in patients with gastric cancer, supporting the hypothesis that the AMF/AMF receptor pathway plays an important role in multiple aspects of cancer biology.
Combination of Imatinib Mesylate with Autologous Leukocyte-Derived Heat Shock Protein and Chronic Myelogenous Leukemia
Authors: Li Zihai , Qiao Yi , Liu Bei , Laska Elizabeth J. , Chakravarthi Priyamvadha , Kulko Judith M. , Bona Robert D. , Fang Min , Hegde Upendra , Moyo Victor , Tannenbaum Susan H. , Ménoret Antoine , Gaffney Judy , Glynn Laura , Runowicz Carolyn D. , Srivastava Pramod K.
Published: September 2005

Purpose: To test the feasibility, safety, immunogenicity, and clinical efficacy of an autologous vaccine of leukocyte-derived heat shock protein 70-peptide complexes (Hsp70PC), in conjunction with imatinib mesylate, in patients with chronic myeloid leukemia (CML) in chronic phase.

Experimental Design: Patients had cytogenetic or molecular evidence of disease, despite treatment with imatinib mesylate for all except one patient, at the beginning of study. Hsp70PCs were purified from the leukopheresed peripheral blood mononuclear cells and were administered in eight weekly intradermal injections at 50 μg/dose without adjuvant. Clinical responses were assessed by bone marrow analysis before and after vaccinations. An IFN-γ enzyme-linked immunospot assay was used to estimate the effect of treatment on natural killer cells and T cells against CML.

Results: Twenty patients were treated. The manufacturing of Hsp70PCs was successful and the administration was safe for all patients. Minimal or no side effects were reported. Clinical responses were seen in 13 of 20 patients as measured by cytogenetic analysis of bone marrow Philadelphia chromosome–positive cells in metaphases and/or, when possible, the level of Bcr/Abl transcript by PCR. Immunologic responses were observed in 9 of 16 patients analyzed, characterized by an increase in the frequency of CML-specific IFN-γ-producing cells and IFN-γ-secreting natural killer cells in the blood. A significant correlation between clinical responses and immunologic responses was observed.

Conclusions: Autologous Hsp70PC vaccination is feasible and safe. When combined with imatinib mesylate, it is associated with immunologic and possible clinical responses against CML in chronic phase.
Pulmonary Squamous Cell Carcinoma following Head and Neck Squamous Cell Carcinoma: Metastasis or Second Primary?
Authors: Geurts Tom W. , Nederlof Petra M. , van den Brekel Michiel W.M. , van't Veer Laura J. , de Jong Daphne , Hart August A.M. , van Zandwijk Nico , Klomp Houke , Balm Alfons J.M. , van Velthuysen Marie-Louise F.
Published: September 2005

Purpose: To distinguish a metastasis from a second primary tumor in patients with a history of head and neck squamous cell carcinoma and subsequent pulmonary squamous cell carcinoma.

Experimental Design: For 44 patients with a primary squamous cell carcinoma of the head and neck followed by a squamous cell carcinoma of the lung, clinical data, histology, and analysis of loss of heterozygosity (LOH) were used to differentiate metastases from second primary tumors.

Results: Clinical evaluation suggested 38 patients with metastases and 6 with second primaries. We developed a novel interpretation strategy based on biological insight and on our observation that multiple LOH on different chromosome arms are not independent. LOH analysis indicated metastatic disease in 19 cases and second primary squamous cell carcinoma in 24 cases. In one case, LOH analysis was inconclusive. For 25 patients, LOH supported the clinical scoring, and in 18 cases, it did not. These 18 discordant cases were all considered to be second primary tumors by LOH analysis.

Conclusions: A considerable number of squamous cell lung lesions (50% in this study), clinically interpreted as metastases, are suggested to be second primaries by LOH analysis. For these patients, a surgical approach with curative intent may be justified.
Targeting Matrilysin and Its Impact on Tumor Growth In vivo: The Potential Implications in Breast Cancer Therapy
Authors: Jiang Wen G. , Davies Gaynor , Martin Tracey A. , Parr Christian , Watkins Gareth , Mason Malcolm D. , Mokbel Kefah , Mansel Robert E.
Published: September 2005

Introduction: Matrilysin (MMP-7) is a metalloproteinase that is involved in the degradation of extracellular matrix, invasion, and tumor progression. The current study examined if targeting matrilysin using retroviral ribozyme transgenes may have an impact on breast cancer cells and may have clinical implications.

Experimental Design: Retroviral hammerhead ribozyme transgenes were designed to specifically target human matrilysin mRNA. The breast cancer cell MDA-MB-231 was transfected with either a retroviral matrilysin transgene or a control retroviral transgene. Stably transfected cells were tested for their invasiveness and migratory properties in vitro. The cells were also used in creating a tumor model in athymic nude mice in which the growth of tumors and levels of matrilysin were assessed. In addition, levels of both protein and mRNA of matrilysin were investigated in a cohort of human breast tumors.

Results: Expression of matrilysin in MDA-MB-231 was successfully eliminated by the retroviral hammerhead ribozyme transgene for matrilysin as revealed by reverse transcription-PCR. Matrilysin transgene–transduced cancer cells (MDA-MB-231ΔMatrilysin) exhibited a significantly lower degree of invasion (number of invading cells 16.0 ± 2.5) compared with wild type (MDA-MB-231WT; 26.2 ± 6.2, P < 0.05) or control transgene-transduced cancer cells (MDA-MB-231pRevTRE; 25.3 ± 4.2, P < 0.01). However, the rate of growth of the cells in vitro was not significantly affected. In the in vivo tumor model, MDA-MB-231ΔMatrilysin tumors, which had very low levels of immunoreactive matrilysin, grew at a significantly lower rate (0.24 ± 0.03 cm3, 4 weeks after inoculation) compared with the wild-type MDA-MB-231WT (1.46 ± 0.04 cm3) and MDA-MB-231pRevTRE (1.12 ± 1.0 cm3) tumors. In human breast tumors, breast cancer cells stained matrilysin at a significantly higher density, compared with normal mammary epithelium. The highest level of matrilysin was seen in high-grade tumors and that from patients with moderate and poor prognosis. Finally, high levels of matrilysin were significantly linked with a poor long-term survival (P = 0.0143).

Conclusion: Matrilysin, which is aberrantly expressed in human breast tumors, can be effectively eliminated from breast cancer cells by way of hammerhead ribozyme transgene. Elimination of matrilysin is associated with low invasiveness and slow tumor growth. Taken together, the study suggests that targeting matrilysin may have important therapeutic implications.
Enhanced Production of Interleukin 6 in Peripheral Blood Monocytes Stimulated with Mucins Secreted into the Bloodstream
Authors: Yokoigawa Norio , Takeuchi Noriko , Toda Munetoyo , Inoue Mizue , Kaibori Masaki , Yanagida Hidesuke , Tanaka Hironori , Ogura Tokuhiro , Takada Hideho , Okumura Tadayoshi , Kwon A-H , Kamiyama Yasuo , Nakada Hiroshi
Published: September 2005

Purpose: It has been reported that tumor progression is correlated with the serum level of interleukin 6 (IL-6). The purpose of this study was to investigate by what mechanism, other than production from tumor cell, the serum level of IL-6 is elevated in the tumor-bearing state.

Experimental Design: Monocytes from healthy donors were cultured in the presence of sera from colon cancer patients, and the activity to elevate IL-6 production was estimated. This activity of serum was also examined after various biochemical treatments.

Results: When monocytes from healthy donors were cultured in the presence of sera from patients with colon cancer, secretion of IL-6 from the cells was markedly elevated. Serum proteins were fractionated on Sepharose 4B and the activity to elevate IL-6 production was found in the excluded fractions. Sialyl Tn antigen was detected in these same fractions. By excluding some mucins from the serum, the inducing activity was reduced to 40% of the original level. Furthermore, we purified mucins from the conditioned medium of colon cancer cells. Production of IL-6 was effectively elevated by a small amount of purified mucins in a dose-dependent manner. When the inducing activity was examined in the presence of binding or competitive inhibitors to the scavenger receptor, the effect was remarkably reduced.

Conclusions: Mucins secreted from colon cancer cells into the bloodstream induce production of IL-6 in peripheral blood monocytes through the scavenger receptor, which may be responsible for the high level of serum IL-6 in colon cancer patients.
Genetic Classification of Lung Adenocarcinoma Based on Array-Based Comparative Genomic Hybridization Analysis: Its Association with Clinicopathologic Features
Authors: Shibata Tatsuhiro , Uryu Satomi , Kokubu Akiko , Hosoda Fumie , Ohki Misao , Sakiyama Tokuki , Matsuno Yoshihiro , Tsuchiya Ryosuke , Kanai Yae , Kondo Tadashi , Imoto Issei , Inazawa Johji , Hirohashi Setsuo
Published: September 2005

The array-based comparative genomic hybridization using microarrayed bacterial artificial chromosome clones allows high-resolution analysis of genome-wide copy number changes in tumors. To analyze the genetic alterations of primary lung adenocarcinoma in a high-throughput way, we used laser-capture microdissection of cancer cells and array comparative genomic hybridization focusing on 800 chromosomal loci containing cancer-related genes. We identified a large number of chromosomal numerical alterations, including frequent amplifications on 7p12, 11q13, 12q14-15, and 17q21, and two homozygous deletions on 9p21 and one on 8p23. Unsupervised hierarchical clustering analysis of multiple alterations revealed three subgroups of lung adenocarcinoma that were characterized by the accumulation of distinct genetic alterations and associated with smoking history and gender. The mutation status of the epidermal growth factor receptor (EGFR) gene was significantly associated with specific genetic alterations and supervised clustering analysis based on EGFR gene mutations elucidated a subgroup including all EGFR gene mutated tumors, which showed significantly shorter disease-free survival. Our results suggest that there exist multiple molecular carcinogenesis pathways in lung adenocarcinoma that may associate with smoking habits and gender, and that genetic cancer profiling will reveal previously uncharacterized genetic heterogeneity of cancer and be beneficial in estimating patient prognosis and discovering novel cancer-related genes including therapeutic targets.
Voltage-Gated Sodium Channel Expression and Potentiation of Human Breast Cancer Metastasis
Authors: Fraser Scott P. , Diss James K.J. , Chioni Athina-Myrto , Mycielska Maria E. , Pan Huiyan , Yamaci Rezan F. , Pani Filippo , Siwy Zuzanna , Krasowska Monika , Grzywna Zbigniew , Brackenbury William J. , Theodorou Dimis , Koyutürk Meral , Kaya Handan , Battaloglu Esra , De Bella Manuela Tamburo , Slade Martin J. , Tolhurst Robert , Palmieri Carlo , Jiang Jie , Latchman David S. , Coombes R. Charles , Djamgoz Mustafa B.A.
Published: September 2005

Purpose: Ion channel activity is involved in several basic cellular behaviors that are integral to metastasis (e.g., proliferation, motility, secretion, and invasion), although their contribution to cancer progression has largely been ignored. The purpose of this study was to investigate voltage-gated Na+ channel (VGSC) expression and its possible role in human breast cancer.

Experimental Design: Functional VGSC expression was investigated in human breast cancer cell lines by patch clamp recording. The contribution of VGSC activity to directional motility, endocytosis, and invasion was evaluated by in vitro assays. Subsequent identification of the VGSC α-subunit(s) expressed in vitro was achieved using reverse transcription-PCR, immunocytochemistry, and Western blot techniques and used to investigate VGSCα expression and its association with metastasis in vivo.

Results: VGSC expression was significantly up-regulated in metastatic human breast cancer cells and tissues, and VGSC activity potentiated cellular directional motility, endocytosis, and invasion. Reverse transcription-PCR revealed that Nav1.5, in its newly identified “neonatal” splice form, was specifically associated with strong metastatic potential in vitro and breast cancer progression in vivo. An antibody specific for this form confirmed up-regulation of neonatal Nav1.5 protein in breast cancer cells and tissues. Furthermore, a strong correlation was found between neonatal Nav1.5 expression and clinically assessed lymph node metastasis.

Conclusions: Up-regulation of neonatal Nav1.5 occurs as an integral part of the metastatic process in human breast cancer and could serve both as a novel marker of the metastatic phenotype and a therapeutic target.
Inhibition of Tumor Growth by RGD Peptide–Directed Delivery of Truncated Tissue Factor to the Tumor Vasculature
Authors: Kessler Torsten , Bieker Ralf , Padró Teresa , Schwöppe Christian , Persigehl Thorsten , Bremer Christoph , Kreuter Michael , Berdel Wolfgang E. , Mesters Rolf M.
Published: September 2005

Selective activation of blood coagulation in tumor vessels with subsequent tumor infarction is a promising anticancer strategy. To this end, a fusion protein consisting of the extracellular domain of tissue factor [truncated tissue factor (tTF)] was fused to the peptide GRGDSP selectively targeting αv-integrins on tumor endothelial cells. tTF-RGD retained its thrombogenic and integrin-binding activity in vitro. In vivo studies in mice bearing human adenocarcinomas (CCL185), melanoma (M21), and fibrosarcoma (HT1080) revealed that i.v. administration of tTF-RGD induced thrombotic occlusion of tumor vessels resulting in tumor growth retardation or regression in all three types of solid tumors. No apparent side effects, such as thrombosis, in other organs or other treatment-related toxicities were observed. Reduced tumor blood flow in tTF-RGD–treated animals as determined by contrast-enhanced magnetic resonance imaging underlines the proposed mechanism. In conclusion, we consider RGD peptide–directed delivery of tTF as alternative to previously used antibody fusion proteins. Small peptide-directed delivery of coaguligands does not cause immunologic side effects and those caused by accumulation in the reticuloendothelial system. This is the first report to describe the induction of selective thrombosis in tumor vessels by RGD peptide–directed delivery of tTF, which may be a promising strategy for the treatment of cancer.
Enhancement of Cisplatin Sensitivity of Cisplatin-Resistant Human Cervical Carcinoma Cells by Bryostatin 1
Authors: Mohanty Sanghamitra , Huang Jie , Basu Alakananda
Published: September 2005

Purpose: Bryostatin 1, a unique protein kinase C (PKC) activator, is already in the clinical trials. An understanding of complex regulation of PKC by bryostatin 1 is essential for effective use of bryostatin 1 in the clinic. We have previously shown that the ability of bryostatin 1 to enhance cisplatin sensitivity correlated with its ability to down-regulate PKCδ in HeLa cells. We have investigated how bryostatin 1 influences PKCδ regulation in cisplatin-resistant HeLa (HeLa/CP) cells, and if bryostatin 1 could be used to reverse cisplatin resistance.

Experimental Design: Phorbol 12,13-dibutyrate (PDBu), bryostatin 1, and small interfering RNA were used to manipulate PKC level/activation status. Cell death was monitored by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, Annexin V dye-binding assay, and analysis of hypodiploid peak in a flow cytometer.

Results: Bryostatin 1 elicited a biphasic concentration response on PKCδ down-regulation and cisplatin-induced cell death in HeLa/CP cells; the maximum effect was achieved with 1 nmol/L bryostatin 1. Down-regulation of PKCα increased with increasing concentrations of bryostatin 1. PDBu induced down-regulation of PKCα in HeLa and HeLa/CP cells but it had little effect on PKCδ down-regulation in HeLa/CP cells. However, both PDBu and bryostatin 1 enhanced the sensitivity of HeLa/CP cells to cisplatin. Knockdown of PKCδ by small interfering RNA inhibited cisplatin-induced apoptosis but knockdown of PKCα enhanced cisplatin-induced cell death.

Conclusions: These results suggest that although PKCδ acts as a proapoptotic protein, full-length PKCδ may inhibit cisplatin-induced cell death. Thus, persistent activation/down-regulation of PKCδ by bryostatin 1 was associated with cisplatin sensitization. Furthermore, PKCα acts as an antiapoptotic protein and down-regulation of PKCα by PDBu was associated with cellular sensitization to cisplatin.
Glioblastoma Patients Exhibit Circulating Tumor-Specific CD8+ T Cells
Authors: Tang Jie , Flomenberg Phyllis , Harshyne Larry , Kenyon Lawrence , Andrews David W.
Published: September 2005

Purpose: There is growing interest in developing cellular immune therapies for glioblastoma multiforme, but little is known about tumor-specific T-cell responses. A glioblastoma multiforme–specific T-cell assay was developed using monocyte-derived dendritic cells to present tumor antigens from the established glioblastoma multiforme cell line U118.

Experimental Design: Peripheral blood mononuclear cells (PBMC) and tumor cells were obtained from nine patients with newly diagnosed brain tumors: five glioblastoma multiforme, two oligodendroglioma, one ependymoma, and one astrocytoma. PBMCs were incubated overnight with autologous tumor cells or autologous dendritic cells loaded with a U118 cell lysate, and responses were detected by IFN-γ ELISPOT and cytokine flow cytometry assays.

Results: PBMCs from all glioblastoma multiforme patients exhibited IFN-γ responses to autologous tumor but not to HLA-mismatched U118 cells. Glioblastoma multiforme–specific IFN-γ responses were primarily mediated by CD8+ T cells and represented ∼2% of total CD8+ T cells. Additionally, all glioblastoma multiforme patients responded to autologous dendritic cells loaded with U118 lysate but not with low-grade astrocytoma cell lysates. PBMCs from four patients with other brain tumor types and one normal donor failed to respond to U118 lysate–loaded autologous dendritic cells. These data indicate that the IFN-γ responses to U118 lysate–loaded autologous dendritic cells are glioblastoma multiforme specific. Moreover, PBMCs stimulated 1 to 2 weeks with U118 lysate–loaded dendritic cells exhibited MHC class I–restricted cytotoxicity against autologous tumor cells.

Conclusions: Glioblastoma multiforme patients exhibit circulating tumor-specific CD8+ T cells that recognize shared tumor antigens from the glioblastoma multiforme cell line U118. These data show that glioblastoma multiformes are immunogenic and support the development of immunotherapy trials.
Generation of Rituximab Polymer May Cause Hyper-Cross-linking–Induced Apoptosis in Non-Hodgkin's Lymphomas
Authors: Zhang Nan , Khawli Leslie A. , Hu Peisheng , Epstein Alan L.
Published: September 2005

Purpose: Although Rituximab has produced significant tumor regressions in lymphoma patients, only 50% respond. Clinically, it has been shown that the major mechanism of action of Rituximab is antibody-dependent cytotoxicity requiring presentation by Fc-bearing cells. To improve the clinical efficacy of Rituximab for the treatment of CD20+ lymphomas, we now describe a new formulation of Rituximab, which, on direct binding to target, can induce apoptosis.

Methods: In this report, enhanced apoptosis was observed by treating CD20+ lymphoma cells with a new polymer formulation of Rituximab. The polymer was produced by formation of a peptide bond using the sugar moiety of dextran (MW 6,000) to generate a clinically relevant reagent for use in vivo.

Results: Comparison of Rituximab with a previously described dimer and the newly generated polymer shows that the polymer induced apoptosis more effectively in CD20+ cells as shown by the terminal deoxyribonucleotidyl transferase–mediated dUTP nick end labeling assay (Rituximab, 3%; dimer, 3%; polymer, 58%). Consistent with these results, the polymer produced marked regression in CD20+ lymphoma xenografts, whereas the dimer and monomer reagents showed little effect. In addition, we were able to show that the level of apoptosis induced in human lymphoma cell lines was in accordance with the extent of both surface CD20 clustering and caspase-3 activation.

Conclusions: These data suggest that hyper-cross-linking–induced apoptosis can be simulated by the use of a dextran polymer of Rituximab, which, when used in vivo, can directly kill CD20+ lymphoma cells and improve the clinical efficacy of this important therapeutic for human B-cell lymphomas.
New Monoclonal Antibodies to Mesothelin Useful for Immunohistochemistry, Fluorescence-Activated Cell Sorting, Western Blotting, and ELISA
Authors: Onda Masanori , Willingham Mark , Nagata Satoshi , Bera Tapan K. , Beers Richard , Ho Mitchell , Hassan Raffit , Kreitman Robert J. , Pastan Ira
Published: September 2005

Purpose: Mesothelin is a cell surface protein that is highly expressed in some malignant tumors, and is a promising target for immunotherapy. Recent data suggests that mesothelin is an adhesive protein and may have a role in the metastases of ovarian cancer. Although a few monoclonal antibodies (MAb) to mesothelin have been produced, they have limitations for the study of expression of native mesothelin because of their low affinity or reactivity only with denatured mesothelin protein. We have produced novel MAbs to mesothelin to help study mesothelin function and to develop improved diagnosis and immunotherapy of mesothelin-expressing tumors.

Experimental Design: Mesothelin-deficient mice were immunized with plasmid cDNA encoding mesothelin, and boosted with a mesothelin-rabbit IgG Fc fusion protein prior to cell fusion. Hybridomas were screened by an ELISA using plates coated with mesothelin-Fc protein.

Results: Seventeen hybridomas producing anti-mesothelin antibodies were established and shown to react with two epitopes on mesothelin. One group reacts with the same epitope as the low affinity antibody K1 that was originally used to identify mesothelin. The other is a new group that reacts with a new epitope. One antibody from each group was chosen for further study and shown to react strongly on ELISA, on immunohistochemistry, and by fluorescence-activated cell sorting on living cells.

Conclusion: Our two newly established MAbs, MN and MB, have different and useful properties compared with current antibodies used for the detection of mesothelin by immunohistochemistry, fluorescence-activated cell sorting, ELISA, and Western blotting.
Detection of Human Papillomavirus (HPV) 16-Specific CD4+ T-cell Immunity in Patients with Persistent HPV16-Induced Vulvar Intraepithelial Neoplasia in Relation to Clinical Impact of Imiquimod Treatment
Authors: van Poelgeest Mariëtte I.E. , van Seters Manon , van Beurden Marc , Kwappenberg Kitty M.C. , Heijmans-Antonissen Claudia , Drijfhout Jan W. , Melief Cornelis J.M. , Kenter Gemma G. , Helmerhorst Theo J.M. , Offringa Rienk , van der Burg Sjoerd H.
Published: September 2005

Purpose: Topical application of the immune response modifier imiquimod is an alternative approach for the treatment of human papillomavirus (HPV)–positive vulvar intraepithelial neoplasia (VIN) and aims at the immunologic eradication of HPV-infected cells. We have charted HPV16-specific immunity in 29 patients with high-grade VIN and examined its role in the clinical effect of imiquimod treatment.

Experimental Design: The magnitude and cytokine polarization of the HPV16 E2-, E6-, and E7-specific CD4+ T-cell response was charted in 20 of 29 patients by proliferation and cytokine bead array. The relation between HPV16-specific type 1 T-cell immunity and imiquimod treatment was examined in a group of 17 of 29 patients.

Results: HPV16-specific proliferative responses were found in 11 of the 20 patients. In eight of these patients, T-cell reactivity was associated with IFNγ production. Fifteen of the women treated with imiquimod were HPV16+, of whom eight displayed HPV16 E2- and E6-specific T-cell immunity before treatment. Imiquimod neither enhanced nor induced such immunity in any of the subjects. Objective clinical responses (complete remission or >75% regression) were observed in 11 of the 15 patients. Of these 11 responders, eight patients displayed HPV16-specific type 1 CD4+ T-cell immunity, whereas three lacked reactivity. Notably, the four patients without an objective clinical response also lacked HPV16-specific type 1 T-cell immunity.

Conclusions: HPV16-specific IFNγ-associated CD4+ T-cell immunity, although not essential for imiquimod-induced regression of VIN lesions, may increase the likelihood of a strong clinical response (P = 0.03).
Isolated Loss of PMS2 Expression in Colorectal Cancers: Frequency, Patient Age, and Familial Aggregation
Authors: Gill Sharlene , Lindor Noralane M. , Burgart Lawrence J. , Smalley Regenia , Leontovich Olga , French Amy J. , Goldberg Richard M. , Sargent Daniel J. , Jass Jeremy R. , Hopper John L. , Jenkins Mark A. , Young Joanne , Barker Melissa A. , Walsh Michael D. , Ruszkiewicz Andrew R. , Thibodeau Stephen N.
Published: September 2005

Purpose: Most colorectal cancers that have high levels of microsatellite instability (MSI-H) show loss of immunohistochemical expression of proteins that participate in the DNA mismatch repair process, most often involving MLH1 and MSH2. Less commonly, a third DNA mismatch repair protein, MSH6, may also be lost as the primary event. Rarely, tumors with MSI-H show normal expression of these three proteins. The genetic deficiency leading to the MSI-H phenotype in such cases is unknown. PMS2 is another member of the DNA mismatch repair complex. Its expression is generally lost in tumors with MLH1 loss of expression. Rarely, there is selective loss of PMS2 expression. We sought to describe the frequency and clinical correlates of selective loss of expression of PMS2 with the MSI-H tumor phenotype.

Experimental Design: Two thousand seven hundred nineteen colorectal cancers from both clinic- and research-based ascertainment were studied. Tumor MSI testing and immunohistochemistry for MLH1, MSH2, MSH6, and PMS2 were conducted. Medical records were abstracted for age at diagnosis, gender, colorectal cancer site, and family history.

Results: Five hundred thirty-five of the 2,719 tumors were MSI-H. Of these, 93% showed loss of expression of MLH1, MSH2, and/or MSH6. Thirty-eight showed normal expression for these proteins. PMS2 immunohistochemical staining was successful in 32 of 38 of these tumors. Of the 32, 23 showed selective loss of expression of PMS2. This was associated with young age of diagnosis and right-sided location but not with a striking family history of cancer.

Conclusions: Overall, 97% of the MSI-H tumors showed loss of expression for one or more of these four mismatch repair proteins. Selective loss of expression of PMS2 was present in 72% of cases in which colorectal cancers had an MSI-H phenotype but no alteration of expression of MLH1, MSH2, and MSH6. The underlying mechanism involved cannot be determined from this study but could involve point mutations in other DNA mismatch repair genes with retention of immunohistochemical expression, somatic inactivation of PMS2, or germ line mutation of PMS2.
Molecular Evidence Supporting Field Effect in Urothelial Carcinogenesis
Authors: Jones Timothy D. , Wang Mingsheng , Eble John N. , MacLennan Gregory T. , Lopez-Beltran Antonio , Zhang Shaobo , Cocco Amy , Cheng Liang
Published: September 2005

Purpose: Human urothelial carcinoma is thought to arise from a field change that affects the entire urothelium. Multifocality of urothelial carcinoma is a common finding at endoscopy and surgery. Whether these coexisting tumors arise independently or are derived from the same tumor clone is uncertain. Molecular analysis of microsatellite alterations and X-chromosome inactivation status in the cells from each coexisting tumor may further our understanding of urothelial carcinogenesis.

Experimental Design: We examined 58 tumors from 21 patients who underwent surgical excision for urothelial carcinoma. All patients had multiple separate foci of urothelial carcinoma (two to four) within the urinary tract. Genomic DNA samples were prepared from formalin-fixed, paraffin-embedded tissue sections using laser-capture microdissection. Loss of heterozygosity (LOH) assays for three microsatellite polymorphic markers on chromosome 9p21 (IFNA and D9S171), regions of putative tumor suppressor gene p16, and on chromosome 17p13 (TP53), the p53 tumor suppressor gene locus, were done. X-chromosome inactivation analysis was done on the urothelial tumors from 11 female patients.

Results: Seventeen of 21 (81%) cases showed allelic loss in one or more of the urothelial tumors in at least one of the three polymorphic markers analyzed. Concordant allelic loss patterns between each coexisting urothelial tumor were seen in only 3 of 21 (14%) cases. A concordant pattern of nonrandom X-chromosome inactivation in the multiple coexisting urothelial tumors was seen in only 3 of 11 female patients; of these 3 cases, only one displayed an identical allelic loss pattern in all of the tumors on LOH analysis.

Conclusion: LOH and X-chromosome inactivation assays show that the coexisting tumors in many cases of multifocal urothelial carcinoma have a unique clonal origin and arise from independently transformed progenitor urothelial cells, supporting the “field effect” theory for urothelial carcinogenesis.
The Role of Targeted Agents in Adjuvant Therapy for Non–Small Cell Lung Cancer
Authors: Kelly Karen
Published: September 2005

The recent survival benefit of adjuvant chemotherapy in early stage non–small cell lung cancer provides optimism for the future success of targeted therapy in this setting. It is important that we begin to explore molecularly targeted agents in the adjuvant arena, but how best to accomplish this in the face of these new findings presents a challenge. Criteria for selecting promising targeted therapies and optimal trial designs to evaluate them expeditiously in the adjuvant setting are clearly needed.
Tyrosine Kinase Inhibitors in Renal Cell Carcinoma
Authors: Potti Anil , George Daniel J.
Published: September 2005

Current standard treatments for patients with metastatic (stage IV) renal cell carcinoma involve both surgical removal of tumors and treatment with biological agents such as interleukin 2 and/or IFN-α. Unfortunately, such approaches are inadequate for most patients with stage IV disease; the result is a median time to progression of 2 to 4 months and an overall survival of 6 to 17 months. Standard chemotherapy has been uniformly disappointing in this disorder. It is clear that new therapies are needed to approach these patients. Recently, a greater understanding of cancer genetics has led to the successful development of novel therapeutics directed against targets linked to specific types of cancer. During the past decade, researchers have identified the von Hippel-Lindau (VHL) gene as an important tumor suppressor in clear cell carcinoma of the kidney. Elucidation of the VHL gene product (pVHL) and its regulation of hypoxia-inducible factor signaling have created a potential genetic basis for growth factor-targeted strategies in this disease. This review will focus on the potential growth factor targets in clear cell carcinoma, their relation to VHL and hypoxia-inducible factor, and the clinical challenges that face their development.
Vascular Targeting Agents as Cancer Therapeutics
Authors: Thorpe Philip E.
Published: September 2005

Vascular targeting agents (VTAs) for the treatment of cancer are designed to cause a rapid and selective shutdown of the blood vessels of tumors. Unlike antiangiogenic drugs that inhibit the formation of new vessels, VTAs occlude the pre-existing blood vessels of tumors to cause tumor cell death from ischemia and extensive hemorrhagic necrosis. Tumor selectivity is conferred by differences in the pathophysiology of tumor versus normal tissue vessels (e.g., increased proliferation and fragility, and up-regulated proteins). VTAs can kill indirectly the tumor cells that are resistant to conventional antiproliferative cancer therapies, i.e., cells in areas distant from blood vessels where drug penetration is poor, and hypoxia can lead to radiation and drug resistance. VTAs are expected to show the greatest therapeutic benefit as part of combined modality regimens. Preclinical studies have shown VTA-induced enhancement of the effects of conventional chemotherapeutic agents, radiation, hyperthermia, radioimmunotherapy, and antiangiogenic agents. There are broadly two types of VTAs, small molecules and ligand-based, which are grouped together, because they both cause acute vascular shutdown in tumors leading to massive necrosis. The small molecules include the microtubulin destabilizing drugs, combretastatin A-4 disodium phosphate, ZD6126, AVE8062, and Oxi 4503, and the flavonoid, DMXAA. Ligand-based VTAs use antibodies, peptides, or growth factors that bind selectively to tumor versus normal vessels to target tumors with agents that occlude blood vessels. The ligand-based VTAs include fusion proteins (e.g., vascular endothelial growth factor linked to the plant toxin gelonin), immunotoxins (e.g., monoclonal antibodies to endoglin conjugated to ricin A), antibodies linked to cytokines, liposomally encapsulated drugs, and gene therapy approaches. Combretastatin A-4 disodium phosphate, ZD6126, AVE8062, and DMXAA are undergoing clinical evaluation. Phase I monotherapy studies have shown that the agents are tolerated with some demonstration of single agent efficacy. Because efficacy is expected when the agents are used with conventional chemotherapeutic drugs or radiation, the results of Phase II combination studies are eagerly awaited.
A Phase I Dose-Escalation and Pharmacokinetic Study of Brostallicin (PNU-166196A), a Novel DNA Minor Groove Binder, in Adult Patients with Advanced Solid Tumors
Authors: Lockhart A. Craig , Howard Martin , Hande Kenneth R. , Roth Bruce J. , Berlin Jordan D. , Vreeland Franzanne , Campbell Angela , Fontana Erminia , Fiorentini Francesca , Fowst Camilla , Paty Victoria A. , Lankford Odessa , Rothenberg Mace L.
Published: September 2005

Purpose: This study was performed to determine the maximum tolerated dose, dose-limiting toxicities, and pharmacokinetics of brostallicin, a nonalkylating DNA minor groove binder and a synthetic derivative of distamycin A, given as a weekly i.v. infusion.

Experimental Design: Using an accelerated dose escalation design, patients with advanced solid tumor malignancies were treated with brostallicin administered as a 10-min i.v. infusion on days 1, 8, and 15 of a 28-day cycle. The starting dose of brostallicin was 0.3 mg/m2/week. To study the pharmacokinetic behavior of brostallicin, serial blood samples were obtained before and after the first and last infusions during cycle 1, and in cycles 2 and 4 in a limited number of patients.

Results: Fourteen patients received 32 complete cycles of brostallicin. Dose-limiting toxicity was febrile neutropenia and was observed in 3 of 5 patients treated at 4.8 mg/m2/week. The maximum tolerated dose and recommended Phase II dose was 2.4 mg/m2/week. The mean ± SD terminal half-life at the maximum tolerated dose was 4.6 ± 4.1 h. There was moderate distribution of brostallicin into tissues, and the clearance was ∼20% of the hepatic blood flow. The area under the concentration time curve0-∞ of brostallicin increased in a dose-linear fashion. No significant relationship was observed between any plasma pharmacokinetic parameter and clinical toxicities. There were no objective responses during the trial, but 5 patients had stable disease after two cycles of treatment.

Conclusions: The dose-limiting toxicity of weekly brostallicin was neutropenia. Systemic exposure increases linearly with dose. The recommended dose for Phase II studies is 2.4 mg/m2 on days 1, 8, and 15 of a 28-day cycle.