bluuebunny/crossref_metadata_2025 huggingface dataset:
Myeloperoxidase Is a Key Regulator of Oxidative Stress–Mediated Apoptosis in Myeloid Leukemic Cells
Authors: Nakazato Tomonori , Sagawa Morihiko , Yamato Kenji , Xian Mingji , Yamamoto Takehiro , Suematsu Makoto , Ikeda Yasuo , Kizaki Masahiro
Published: September 2007

Purpose: We reported previously that reactive oxygen species (ROS) are key mediators of apoptosis induced by a polyphenol, (−)-epigallocatechin-3-gallate (EGCG), in myeloid leukemic cells. This study aimed to further examine the mechanism of ROS-mediated apoptosis induced by EGCG and its relationship to the heme enzyme myeloperoxidase (MPO).

Experimental Design: We established stably transfected K562 cells expressing wild-type and mutant MPO. Then, sensitivity against EGCG and other ROS-inducing agent was examined and further investigated the detailed molecular mechanism of ROS-inducing apoptosis in MPO-positive leukemic cells.

Results: EGCG rapidly induced apoptosis in MPO-positive leukemia cells. Preincubation of myeloid leukemic cells with the MPO-specific inhibitor, 4-aminobenzoic acid hydrazide, and the heme biosynthesis inhibitor, succinylacetone, resulted in inhibition of the intracellular MPO activity, ROS production, and induction of apoptosis following addition of EGCG. Overexpression of MPO sensitized EGCG-resistant K562 cells to apoptosis induced by EGCG. In contrast, an enzymatically inactive MPO mutant–expressing K562 cell could not respond to EGCG, suggesting that MPO is important for determining the sensitivity to EGCG-induced oxidative stress. Hypochlorous acid scavengers and the hydroxyl radical (·OH) scavenger inhibited EGCG-induced apoptosis in myeloid leukemic cells. The fluorescence intensity of both aminophenyl fluorescein– and hydroxyphenyl fluorescein–loaded myeloid leukemic cells significantly increased on stimulation with EGCG, indicating that EGCG generated highly toxic ROS in myeloid leukemic cells.

Conclusions: These results indicated that highly toxic ROS such as ·OH generated via the hydrogen peroxide/MPO/halide system induce apoptosis and that ROS may be the direct mediators of EGCG-induced apoptosis in MPO-positive leukemic cells.
Activation of the Interleukin-6/STAT3 Antiapoptotic Pathway in Esophageal Cells by Bile Acids and Low pH: Relevance to Barrett's Esophagus
Authors: Dvorak Katerina , Chavarria Melissa , Payne Claire M. , Ramsey Lois , Crowley-Weber Cara , Dvorakova Barbora , Dvorak Bohuslav , Bernstein Harris , Holubec Hana , Sampliner Richard E. , Bernstein Carol , Prasad Anil , Green Sylvan B. , Garewal Harinder
Published: September 2007

Objectives: The molecular factors contributing to the development of Barrett's esophagus (BE) are unclear. Our previous studies showed that BE tissues secrete interleukin-6 (IL-6) and express proteins associated with IL-6 signaling, including IL-6 receptor, activated signal transducer and activators of transcription 3 (STAT3), and antiapoptotic proteins Bcl-xL and Mcl-1. Here, we test the hypothesis that bile acids and gastric acids, two components of refluxate associated with gastresophageal reflux disease, activate the IL-6/STAT3 pathway.

Materials and Methods: Immunohistochemistry was used to assess levels of phosphorylated STAT3 in esophageal tissue samples from BE patients with different grades of dysplasia. Seg-1 esophageal adenocarcinoma cells were evaluated for STAT3 activation and IL-6 and Bcl-xL expression by molecular biology techniques, including Western blot, reverse transcription–PCR, and ELISA after exposure to control media (pH 7.4), media supplemented with a 0.1 mmol/L bile acid cocktail with media at pH 4 or media at pH 4 with bile acid cocktail.

Results: Immunohistochemical analysis showed that activated, phosphorylated STAT3 is expressed in nuclei of dysplastic BE and cancer tissues. Treatment of Seg-1 cells with media containing bile acid cocktail and acidified to pH 4 resulted in increased activation of STAT3, IL-6 secretion, and increased expression of Bcl-xL. Inhibition of the STAT3 pathway using STAT3 small interfering RNA or Janus-activated kinase inhibitor resulted in increased apoptosis.

Conclusions: The IL-6/STAT3 antiapoptotic pathway is induced by short exposure to bile acid cocktail and low pH. This alteration, if persistent in vivo, may underlie the development of dysplastic BE and tumor progression.
Low-Dose Paclitaxel Prior to Intratumoral Dendritic Cell Vaccine Modulates Intratumoral Cytokine Network and Lung Cancer Growth
Authors: Zhong Hua , Han Baohui , Tourkova Irina L. , Lokshin Anna , Rosenbloom Alan , Shurin Michael R. , Shurin Galina V.
Published: September 2007

Purpose: The main goal of this study was to provide the “proof-of-principle” that low-dose paclitaxel is able to change the tumor microenvironment and improve the outcome of intratumoral dendritic cell vaccine in a murine lung cancer model.

Experimental Design: We evaluated the antitumor potential and changes in the intratumoral milieu of a combination of low-dose chemotherapy and dendritic cell vaccine in the Lewis lung carcinoma model in vivo.

Results: The low-dose paclitaxel, which induced apoptosis in ∼10% of tumor cells, was not toxic to bone marrow cells and dendritic cells and stimulated dendritic cell maturation and function in vitro. Although tumor cells inhibited dendritic cell differentiation in vitro, this immunosuppressive effect was abrogated by the pretreatment of tumor cells with low-dose paclitaxel. Based on these data, we next tested whether pretreatment of tumor-bearing mice with low-dose paclitaxel in vivo would improve the antitumor potential of dendritic cell vaccine administered intratumorally. Significant inhibition of tumor growth in mice treated with low-dose paclitaxel plus intratumoral dendritic cell vaccine, associated with increased tumor infiltration by CD4+ and CD8+ T cells and elevated tumor-specific IFN-γ production by draining lymph node cells, was revealed. Using a novel intratumoral microdialysis technique and Luminex technology for collecting and characterizing soluble factors released within the tumor bed for several days in live freely moving animals, we showed that low-dose paclitaxel altered the cytokine network at the tumor site.

Conclusions: Our data indicate that low-dose chemotherapy before intratumoral delivery of dendritic cells might be associated with beneficial alterations of the intratumoral microenvironment and thus support antitumor immunity.
Phase I Trial of MS-275, a Histone Deacetylase Inhibitor, Administered Weekly in Refractory Solid Tumors and Lymphoid Malignancies
Authors: Kummar Shivaani , Gutierrez Martin , Gardner Erin R. , Donovan Erin , Hwang Kyunghwa , Chung Eun Joo , Lee Min-Jung , Maynard Kim , Kalnitskiy Mikhail , Chen Alice , Melillo Giovanni , Ryan Qin C. , Conley Barbara , Figg William D. , Trepel Jane B. , Zwiebel James , Doroshow James H. , Murgo Anthony J.
Published: September 2007

Purpose: MS-275 is a histone deacetylase inhibitor that has shown potent and unique anticancer activity in preclinical models. The aims of this phase I trial were to determine the dose-limiting toxicities and maximum tolerated dose of oral MS-275 in humans administered with food on a once weekly schedule and to study the pharmacokinetics of oral MS-275.

Experimental Design: Patients with refractory solid tumors and lymphoid malignancies were treated with oral MS-275 on a once weekly schedule for 4 weeks of a 6-week cycle. Samples for pharmacokinetic and pharmacodynamic analyses were collected during cycle 1. Protein acetylation in subpopulations of peripheral blood mononuclear cells was measured using a multivariable flow cytometry assay.

Results: A total of 22 patients were enrolled, and 19 were considered evaluable for toxicity. The maximum tolerated dose was 6 mg/m2. No National Cancer Institute Common Toxicity Criteria grade 4 toxicities were observed. Dose-limiting grade 3 toxicities were reversible and consisted of hypophosphatemia, hyponatremia, and hypoalbuminemia. Non–dose-limiting grade 3 myelosuppression was also observed. The mean terminal half-life of MS-275 was 33.9 ± 26.2 and the Tmax ranged from 0.5 to 24 h. Although there was considerable interpatient variability in pharmacokinetics, the area under the plasma concentration versus time curve increased linearly with dose.

Conclusions: MS-275 is well tolerated at a dose of 6 mg/m2 administered weekly with food for 4 weeks every 6 weeks. Drug exposure increases linearly with dose, and protein acetylation increased in all the subpopulations of peripheral blood mononuclear cells following MS-275 administration.
Cytotoxic T-Lymphocyte–Associated Antigen-4
Authors: Hodi F. Stephen
Published: September 2007

Previously, the development of immune-based therapies has primarily focused on vaccines and cytokines, yielding benefit in a small percentage of patients. Recent advances in our understanding of the function of costimulatory molecules have revitalized enthusiasm in the development of immune therapies for cancer. This family of proteins possesses properties involved in both lymphocyte activation and immune-inhibitory functions. The costimulatory molecule with the greatest translation into the clinic thus far is CTL-associated antigen-4 (CTLA-4). CTLA-4 engagement leads to T-cell inhibition by two principle mechanisms. The first involves competitive binding with CD28 for B7 on the antigen-presenting cell. The second is direct intracellular inhibitory signals mediated by the CTLA-4 cytoplasmic tail. Numerous clinical trials testing the blockade of CTLA-4 signaling with fully human monoclonal antibodies have treated a variety of cancers, with the most experience in the treatment of metastatic melanoma. Significant antitumor activity as well as potential autoimmune-related toxicities have been observed. Further clinical investigation with CTLA-4 blockade, planned clinical trials testing manipulation of other costimulatory molecules, and continued improvement in understanding of costimulatory pathways present a new era of immune therapies for cancer patients.
Improved Tumor Targeting and Decreased Normal Tissue Accumulation through Extracorporeal Affinity Adsorption in a Two-Step Pretargeting Strategy
Authors: Mårtensson Linda , Nilsson Rune , Ohlsson Tomas , Sjögren Hans-Olov , Strand Sven-Erik , Tennvall Jan
Published: September 2007

Purpose: Evaluation of the possibilities of reducing the accumulation of radiolabeled streptavidin in radiosensitive organs by extracorporeal affinity adsorption (ECAT).

Experimental Design: Rats were injected with biotinylated antibody and subjected to removal of the antibodies from the circulation by ECAT 24 h after injection (avidin column). Animals were then injected with 111In-1,4,7,10-tetra-azacylododecane N,N′,N″,N‴-tetraacetic acid (DOTA)-streptavidin. In a third step, animals were subjected to a second ECAT 8 h after injection to remove the DOTA-streptavidin from the circulation (biotin column). Biodistribution and tumor targeting of DOTA-streptavidin 24 h after injection was determined.

Results: Elimination of biotinylated antibody by ECAT before injection of DOTA-streptavidin increased the tumor targeting by 50%. In addition, the levels of DOTA-streptavidin in liver and lymph nodes were reduced by 60%, which implied a 4.3- and 3.8-fold increase of tumor-to-liver and tumor-to-lymph node ratios, respectively. By doing a second ECAT to remove DOTA-streptavidin from the circulation, accumulation in normal tissues was reduced. However, this latter ECAT also reduced tumor accumulation by 25% (mostly corresponding to radioactivity in the circulation).

Conclusions: ECAT was efficient as a means of removing biotinylated antibodies and would probably also be efficient for the clearance of streptavidin-conjugated antibodies. Conversely, the use of ECAT for removal of radiolabeled streptavidin seems not to offer any advantage.
The La Autoantigen Is a Malignancy-Associated Cell Death Target That Is Induced by DNA-Damaging Drugs
Authors: Al-Ejeh Fares , Darby Jocelyn M. , Brown Michael P.
Published: September 2007

Purpose: To evaluate the La autoantigen as a target for specific monoclonal antibody (mAb) binding in dead cancer cells after use of DNA-damaging chemotherapy.

Experimental Design: In vitro studies of La-specific 3B9 mAb binding to malignant and normal primary cells with and without cytotoxic drug treatment were done using immunoblotting and flow cytometry. Chromatin-binding studies and immunofluorescence detection of γH2AX as a marker of DNA double-stranded breaks together with 3B9 binding assays were done to measure DNA damage responses. Incorporation of a transglutaminase 2 (TG2) substrate and TG2 inhibition were studied to measure protein cross-linking in dead cells.

Results: La was overexpressed in human cancer cell lines with respect to normal primary cells. Within 3 h of the DNA-damaging stimulus, La became chromatin bound when it colocalized with γH2AX. Later, after the stimulus produced cell death, La-specific 3B9 mAb bound specifically and preferentially in the cytoplasm of dead cancer cells. Moreover, 3B9 binding to dead cancer cells increased with increasing DNA damage. Both La and 3B9 became cross-linked in dead cancer cells via TG2 activity.

Conclusion: La autoantigen represents a promising cancer cell death target to determine chemotherapy response because its expression was selectively induced in dead cancer cells after DNA-damaging chemotherapy.
Brief Overview of Preclinical and Clinical Studies in the Development of Intraperitoneal Radioimmunotherapy for Ovarian Cancer
Authors: Meredith Ruby F. , Buchsbaum Donald J. , Alvarez Ronald D. , LoBuglio Albert F.
Published: September 2007

Due to the generally slow and incomplete transit of i.p. infused agents into the circulation, treating disease confined to the peritoneal cavity with chemotherapy, biologics, and/or radionuclides provides a pharmacologic advantage. A higher i.p. concentration can be achieved than could be tolerated by systemic administration. An advantage of i.p. versus i.v. administration for localization of radiolabeled antibodies to small peritoneal surface disease has been shown in animal model and human biopsy studies (1, 2). A recent phase III Gynecologic Oncology Group chemotherapy trial has confirmed a survival advantage for i.p. delivery among women undergoing initial therapy for advanced ovarian cancer (3). Although the therapy was more difficult to tolerate such that 60% of patients randomized to the i.p. arm did not complete the entire regimen, there was a 16-month survival advantage. I.p. radionuclide therapy has been used in treatment of ovarian cancer for more than three decades, but side effects have been problematic in non–tumor-targeted 32P therapy (4). Efforts to improve specificity have used a number of antigens expressed on ovarian cancer cells as targets for selective delivery of radionuclide-conjugates. Mouse models and cell culture have been prominent for preclinical study of agents and strategies in the development of i.p. targeted radionuclide therapy for ovarian cancer. Animal studies, which have directed clinical trials, have shown clear improvement in survival with various modifications including combination chemotherapy, pretargeting, and combination of antibodies over simply delivery of a radiolabeled antibody via i.p. route.
Intraoperative Avidination for Radionuclide Therapy: A Prospective New Development to Accelerate Radiotherapy in Breast Cancer
Authors: Paganelli Giovanni , Ferrari Mahila , Ravasi Laura , Cremonesi Marta , De Cicco Concetta , Galimberti Viviana , Sivolapenko Gregory , Luini Alberto , De Santis Rita , Travaini Laura Lavinia , Fiorenza Maurizio , Chinol Marco , Papi Stefano , Zanna Claudio , Carminati Paolo , Veronesi Umberto
Published: September 2007

Purpose: In a continuous effort to seek for anticancer treatments with minimal side effects, we aim at proving the feasibility of the Intraoperative Avidination for Radionuclide Therapy, a new procedure for partial breast irradiation.

Experimental Design: To assess doses of 90Y-DOTA-biotin to target (i.e., breast tumor bed) and nontarget organs, we did simulation studies with 111In-DOTA-biotin in 10 candidates for conservative breast surgery. Immediately after quadrantectomy, patients were injected with 100-mg avidin in the tumor bed. On the following day, patients were given 111In-DOTA-biotin (∼111 MBq) i.v. after appropriate chase of biotinylated albumin (20 mg) to remove circulating avidin. Biokinetic studies were done by measuring radioactivity in scheduled blood samples, 48-h urine collection, and through scintigraphic images. The medical internal radiation dose formalism (OLINDA code) enabled dosimetry assessment in target and nontarget organs.

Results: Images showed early and long-lasting radioactive biotin uptake in the operated breast. Rapid blood clearance (<1% at 12 h) and urine excretion (>75% at 24 h) were observed. Absorbed doses, expressed as mean ± SD in Gy/GBq, were as low as 0.15 ± 0.05 in lungs, 0.10 ± 0.02 in heart, 0.06 ± 0.02 in red marrow, 1.30 ± 0.50 in kidneys, 1.50 ± 0.30 in urinary bladder, and 0.06 ± 0.02 in total body, whereas in the targeted area, they increased to 5.5 ± 1.1 Gy/GBq (50% ISOROI) and 4.8 ± 1.0 Gy/GBq (30% ISOROI).

Conclusion: Our preliminary results suggest that Intraoperative Avidination for Radionuclide Therapy is a simple and feasible procedure that may improve breast cancer patients' postsurgical management by shortening radiotherapy duration.
A Phase I Study of 90Yttrium-Ibritumomab-Tiuxetan in Children and Adolescents with Relapsed/Refractory CD20-Positive Non–Hodgkin's Lymphoma: A Children's Oncology Group Study
Authors: Cooney-Qualter Erin , Krailo Mark , Angiolillo Anne , Fawwaz Rashid A. , Wiseman Gregory , Harrison Lauren , Kohl Virginia , Adamson Peter C. , Ayello Janet , vande Ven Carmella , Perkins Sherrie L. , Cairo Mitchell S.
Published: September 2007

Purpose: The prognosis for children with recurrent CD20+ non–Hodgkin's lymphoma is dismal. A radiolabeled anti-CD20 antibody, 90yttrium-ibritumomab-tiuxetan (90Y-IT), is Food and Drug Administration approved for adults with recurrent indolent CD20+ B cell–non–Hodgkin's lymphoma. There is no data on the safety and feasibility of 90Y-IT in refractory childhood CD20+ lymphoma.

Experimental Design: Children and adolescents with refractory/relapsed CD20+ lymphoma were eligible for this phase I radioimmunotherapy study. Patients (n = 5) received rituximab (250 mg/m2 i.v.) on days 0 and 7 and indium-111 ibritumomab-tiuxetan (5 mCi i.v.) on day 0. Dosimetry studies were done on days 0, 1, 3, and 6. Immediately after rituximab on day 7, patients received 90Y-IT if dosimetry studies showed <2000 cGy exposure to all solid organs and <300 cGy to marrow, as well as 0.4 mCi/kg in patients with good marrow reserve (n = 3) and 0.1 mCi/kg in patients with poor marrow reserve (after bone marrow transplant; n = 2).

Results: No patients experienced nonhematologic or hematologic dose-limiting toxicity. Human antimurine antibody/human antichimeric antibody incidence was 0%. One patient experienced grade II infusion–related chills associated with rituximab. The following are the means of organ radiation exposure (cGy): kidneys 341 (112-515), liver 345 (83-798), lungs 309 (155-519), marrow 46 (20-78), spleen 565 (161-816), and total body 42 (14-68).

Conclusions: Based on these findings, an expanded investigator-initiated limited institutional phase II study has been designed to further evaluate the safety, tolerability, and response rate with 90Y-IT dose stratification based on marrow reserve.
Combination Treatment with TRA-8 Anti–Death Receptor 5 Antibody and CPT-11 Induces Tumor Regression in an Orthotopic Model of Pancreatic Cancer
Authors: DeRosier Leo Christopher , Buchsbaum Donald J. , Oliver Patsy G. , Huang Zhi-Qiang , Sellers Jeffrey C. , Grizzle William E. , Wang Wenquan , Zhou Tong , Zinn Kurt R. , Long Joshua W. , Vickers Selwyn M.
Published: September 2007

Purpose: Evaluate the response of human pancreatic cancer cell lines and orthotopic tumors to TRA-8, an agonistic antibody to death receptor 5, in combination with irinotecan (CPT-11).

Experimental Design: MIA PaCa-2 and S2VP10 cells were treated with TRA-8 and/or CPT 11. Cell viability was determined by ATP assay. JC-1 mitochondrial depolarization and Annexin V assays confirmed cell death by apoptosis. Immunoblotting was used to evaluate protein changes. MIA PaCa-2 cells were injected into the pancreas of severe combined immunodeficient mice. Mice underwent abdominal ultrasound to quantitate tumor size before and after treatment with twice weekly injections of 200 μg TRA-8 and/or 25 mg/kg CPT-11 for one or two treatment cycles, each lasting 2 weeks.

Results: MIA PaCa-2 cells were more sensitive to TRA-8 and showed additive cytotoxicity, whereas S2VP10 cells showed synergistic cytotoxicity when treated with TRA-8 and CPT-11. Cell death occurred via apoptosis with increased cleavage of caspase-3, caspase-8, and caspase-9 and proapoptotic proteins Bid and poly(ADP)ribose polymerase after combination treatment compared with either agent alone. XIAP and Bcl-XL inhibitors of apoptosis were down-regulated. After a single cycle of in vivo combination therapy, tumor sizes had diminished significantly (P < 0.001) at 8 days posttreatment compared with no treatment, CPT-11, and TRA-8; and there was a 50-day increase in survival with combination treatment over untreated controls (P = 0.0002), 30 days over TRA-8, and a 36-day increase over CPT-11 monotherapy (P = 0.0003). With two cycles of TRA-8/CPT-11 treatment, mean survival time increased significantly (P < 0.001) to 169 days versus untreated controls, TRA-8 or CPT-11 (76, 121, or 108 days, respectively).

Conclusions: Combination TRA-8 and CPT-11 therapy produced enhanced cytotoxicity and survival in the MIA PaCa-2 orthotopic model of pancreatic cancer.
Phase I to III Trials of Anti–B Cell Therapy in Non–Hodgkin's Lymphoma
Authors: Martin Peter , Furman Richard R. , Coleman Morton , Leonard John P.
Published: September 2007

Led by the anti-CD20 antibody rituximab, therapeutic monoclonal antibodies have dramatically altered the treatment of patients with non–Hodgkin's lymphoma. As the understanding of the biology of this novel therapy improves, so does the potential for further progress. There are currently four monoclonal antibodies approved by the Food and Drug Administration for the treatment of B-cell malignancies and dozens more are in various stages of development. The indications for the currently available antibodies, both labeled and unlabeled, are being expanded to include first-line treatment, maintenance strategies, and combinations with chemotherapy. Newer agents are being engineered to target novel antigens, and to interact more specifically with the host immune system. These promising therapeutics face a significant challenge in evaluation and integration in the post-rituximab world.
Bispecific Antibody Pretargeting of Radionuclides for Immuno–Single-Photon Emission Computed Tomography and Immuno–Positron Emission Tomography Molecular Imaging: An Update
Authors: Sharkey Robert M. , Karacay Habibe , McBride William J. , Rossi Edmund A. , Chang Chien-Hsing , Goldenberg David M.
Published: September 2007

Molecular imaging is intended to localize disease based on distinct molecular/functional characteristics. Much of today's interest in molecular imaging is attributed to the increased acceptance and role of 18F-flurodeoxyglucose (18F-FDG) imaging in a variety of tumors. The clinical acceptance of 18F-FDG has stimulated research for other positron emission tomography (PET) agents with improved specificity to aid in tumor detection and assessment. In this regard, a number of highly specific antibodies have been described for different cancers. Although scintigraphic imaging with antibodies in the past was helpful in patient management, most antibody-based imaging products have not been able to compete successfully with the sensitivity afforded by 18F-FDG-PET, especially when used in combination with computed tomography. Recently, however, significant advances have been made in reengineering antibodies to improve their targeting properties. Herein, we describe progress being made in using a bispecific antibody pretargeting method for immuno–single-photon emission computed tomography and immunoPET applications, as contrasted to directly radiolabeled antibodies. This approach not only significantly enhances tumor/nontumor ratios but also provides high signal intensity in the tumor, making it possible to visualize micrometastases of colonic cancer as small as 0.1 to 0.2 mm in diameter using an anti–carcinoembryonic antigen bispecific antibody, whereas FDG failed to localize these lesions in a nude mouse model. Early detection of micrometastatic non–Hodgkin's lymphoma is also possible using an anti-CD20–based bispecific antibody pretargeting procedure. Thus, this bispecific antibody pretargeting procedure may contribute to tumor detection and could also contribute to the detection of other diseases having distinct antigen targets and suitably specific antibodies.
Review: Monoclonal Antibodies to the Vascular Endothelial Growth Factor Receptor-2 in Cancer Therapy
Authors: Youssoufian Hagop , Hicklin Daniel J. , Rowinsky Eric K.
Published: September 2007

Angiogenesis is a fundamental mechanism of cancer growth and invasion. Current translational approaches are using both small-molecule inhibitors and antibodies that modulate various steps of these processes, and several such compounds have already received regulatory approval for the therapy of specific indications in cancer. Among the many molecular targets involved in the control of angiogenesis, the vascular endothelial growth factor receptor-2 (VEGFR-2; or kinase insert domain-containing receptor) is attractive as shown in part by the efficacy of small-molecule inhibitors directed to this receptor. Two small-molecule inhibitors that target VEGFR-2 have recently been granted approval for the treatment of renal cell cancer and gastrointestinal stromal tumors. The development of antibodies that can selectively block VEGFR-2 could potentially result in improved potency or tolerability. Here, we discuss the role of VEGFR-2 in cancer and ongoing efforts to develop highly specific monoclonal antibodies for cancer therapy.
IMC-A12, a Human IgG1 Monoclonal Antibody to the Insulin-Like Growth Factor I Receptor
Authors: Rowinsky Eric K. , Youssoufian Hagop , Tonra James R. , Solomon Phillip , Burtrum Douglas , Ludwig Dale L.
Published: September 2007

Targeted monoclonal antibody therapy is an important strategy in cancer therapeutics. Among the most promising characteristics of therapeutic targets are those that modulate the growth and survival of malignant neoplasms and their sensitivity to anticancer therapies. The insulin-like growth factor-I receptor (IGF-IR) is overexpressed in many types of solid and hematopoietic malignancies, and has been implicated as a principal cause of heightened proliferative and survival signaling. IGF-IR has also been shown to confer resistance to cytotoxic, hormonal, and targeted therapies, suggesting that therapeutics targeting IGF-IR may be effective against a broad range of malignancies. IMC-A12 (ImClone Systems Incorporated), a fully human monoclonal IgG1 antibody that binds with high affinity to the IGF-IR, inhibits ligand-dependent receptor activation and downstream signaling. IMC-A12 also mediates robust internalization and degradation of the IGF-IR. In human tumor xenograft models, IGF-IR blockade by IMC-A12 results in rapid and profound growth inhibition of cancers of the breast, lung, colon, and pancreas, and many other neoplasms. Although promising single-agent activity has been observed, the most impressive effects of targeting the IGF-IR with IMC-A12 have been noted when this agent was combined with cytotoxic agents or other targeted therapeutics. The results with IMC-A12 to date suggest that it may be an effective therapeutic in a diverse array of oncologic indications.
Overexpression of KIAA0101 Predicts High Stage, Early Tumor Recurrence, and Poor Prognosis of Hepatocellular Carcinoma
Authors: Yuan Ray-Hwang , Jeng Yung-Ming , Pan Hung-Wei , Hu Fu-Chang , Lai Po-Lin , Lee Po-Huang , Hsu Hey-Chi
Published: September 2007

Purpose: KIAA0101 is a proliferating cell nuclear antigen–associated factor and involved in cell proliferation. This study is to elucidate its role in the progression, early tumor recurrence (ETR), and prognosis of hepatocellular carcinoma (HCC).

Experimental Design: KIAA0101 mRNA was measured by reverse transcription-PCR in 216 resected, unifocal, primary HCCs and its protein in 164 cases by immunohistochemistry.

Results: KIAA0101 mRNA was overexpressed in 131 (61%) HCCs, and protein was detected in 105 (64%). KIAA0101 mRNA overexpression correlated with higher tumor grade (P = 0.0001), higher tumor stage with vascular invasion and various extents of intrahepatic spread (P = 1 × 10−8), ETR (P = 1.8 × 10−6), and lower 5-year survival (P = 0.0026). Multivariate analysis confirmed that KIAA0101 overexpression was an independent risk factor associated with high-grade tumor (P = 0.0001), high-stage tumor (P < 0.0001), and ETR (P = 0.0052) and thus contributed to poor prognosis. KIAA0101 protein–positive tumor cells accumulated at the borders of tumor macrotrabeculae and were more abundant in tumor thrombi than in the main tumors. Hence, KIAA0101 may contribute to growth advantage and resistance to hypoxic insult. In this series, p53 mutation was detected in 93 of 184 (51%) HCCs. In both p53-mutated and non–p53-mutated HCCs, KIAA0101 overexpression correlated with higher vascular invasion (stages IIIA to IV; all Ps < 0.0001) and, accordingly, led to lower 5-year survival rates (P = 0.011 and 0.029, respectively).

Conclusion: KIAA0101 correlates with enhanced metastatic potential and is a significant prognostic factor of HCC.
CD74: A New Candidate Target for the Immunotherapy of B-Cell Neoplasms
Authors: Stein Rhona , Mattes M. Jules , Cardillo Thomas M. , Hansen Hans J. , Chang Chien-Hsing , Burton Jack , Govindan Serengulam , Goldenberg David M.
Published: September 2007

CD74 is an integral membrane protein that functions as a MHC class II chaperone. Moreover, it has recently been shown to have a role as an accessory-signaling molecule and has been implicated in malignant B-cell proliferation and survival. These biological functions combined with expression of CD74 on malignant B cells and limited expression on normal tissues implicate CD74 as a potential therapeutic target. The anti-CD74 monoclonal antibody LL1 has been humanized (hLL1 milatuzumab or IMMU-115) and can provide the basis for novel therapeutic approaches to B-cell malignancies, particularly because this antibody shows rapid internalization into CD74+ malignant cells. This article reviews the preclinical evaluations of LL1, its humanized form, and isotope, drug, and toxin conjugates. These studies show that unconjugated hLL1 and conjugates of hLL1 constructs with radioisotopes, doxorubicin, and frog RNase have high antitumor activity in non–Hodgkin's lymphoma and multiple myeloma in vitro and in tumor xenograft models. Single-dose studies of hLL1 in monkeys showed no adverse effects but did decrease circulating B and T lymphocytes and natural killer cells. When evaluated in combination with rituximab, either equivalent or improved efficacy, compared with either antibody alone, was observed. CD74 is a new candidate target for the immunotherapy of neoplasms expressing this antigen, which can be exploited using either a naked antibody or conjugated to isotopes, drugs, or toxins.
Targeted Agents: The Rules of Combination
Authors: Kwak Eunice L. , Clark Jeffrey W. , Chabner Bruce
Published: September 2007

The success of molecularly targeted agents (MTA) in the treatment of cancer has led to the investigation of their use in combination with other MTAs and with conventional chemotherapies. An overview of the MTAs that have emerged as Food and Drug Administration–approved drugs is presented, along with a framework for the consideration of how MTAs can best be combined to maximize therapeutic effect.
Kaempferol induces apoptosis in glioblastoma cells through oxidative stress
Authors: Sharma Vivek , Joseph Christy , Ghosh Soumya , Agarwal Anindita , Mishra Manoj Kumar , Sen Ellora
Published: September 2007

Despite recent advances in understanding molecular mechanisms involved in glioblastoma progression, the prognosis of the most malignant brain tumor continues to be dismal. Because the flavonoid kaempferol is known to suppress growth of a number of human malignancies, we investigated the effect of kaempferol on human glioblastoma cells. Kaempferol induced apoptosis in glioma cells by elevating intracellular oxidative stress. Heightened oxidative stress was characterized by an increased generation of reactive oxygen species (ROS) accompanied by a decrease in oxidant-scavenging agents such as superoxide dismutase (SOD-1) and thioredoxin (TRX-1). Knockdown of SOD-1 and TRX-1 expression by small interfering RNA (siRNA) increased ROS generation and sensitivity of glioma cells to kaempferol-induced apoptosis. Signs of apoptosis included decreased expression of Bcl-2 and altered mitochondrial membrane potential with elevated active caspase-3 and cleaved poly(ADP-ribose) polymerase expression. Plasma membrane potential and membrane fluidity were altered in kaempferol-treated cells. Kaempferol suppressed the expression of proinflammatory cytokine interleukin-6 and chemokines interleukin-8, monocyte chemoattractant protein-1, and regulated on activation, normal T-cell expressed and secreted. Kaempferol inhibited glioma cell migration in a ROS-dependent manner. Importantly, kaempferol potentiated the toxic effect of chemotherapeutic agent doxorubicin by amplifying ROS toxicity and decreasing the efflux of doxorubicin. Because the toxic effect of both kaempferol and doxorubicin was amplified when used in combination, this study raises the possibility of combinatorial therapy whose basis constitutes enhancing redox perturbation as a strategy to kill glioma cells. [Mol Cancer Ther 2007;6(9):2544–53]
Involvement of specific matrix metalloproteinases during tumor necrosis factor/IFNγ–based cancer therapy in mice
Authors: Van Roy Maarten , Van Lint Philippe , Van Laere Ineke , Wielockx Ben , Wilson Carole , López-Otin Carlos , Shapiro Stephen , Libert Claude
Published: September 2007

The potent antitumor activity of tumor necrosis factor (TNF) in combination with IFN-γ can only be applied in local regimens due to their strong proinflammatory properties. It has been shown that the broad-spectrum matrix metalloproteinase (MMP) inhibitor BB-94 protects against TNF/IFNγ-induced toxicity without blocking the antitumor effect. Here, we tried to explain this protective role of BB-94 and sought to assign roles to specific MMPs in TNF/IFNγ-induced toxicity. By studying the expression of MMP genes in different organs and in the tumor, we observed that the expression levels of MMP-7, MMP-8, MMP-9, and MMP-12 and tissue inhibitor of metalloproteinase-4 are clearly up-regulated in the liver during therapy. MMP-8 and MMP-9 are also up-regulated in the lung and kidney, respectively. In the tumor, most MMP genes are expressed, but only MMP-3 is up-regulated during TNF/IFNγ treatment. Using MMP-deficient or double-deficient mice, we have shown a mediating role for MMP-3 during TNF/IFNγ treatment in tumor-free and B16BL6 melanoma-bearing mice. By contrast, MMP-12 seemed to have some protective role in both models. However, because most phenotypes were not extremely outspoken, we have to conclude, based on the set of MMP-deficient mice we have studied, that inhibition of a single MMP will probably not increase the therapeutic value of TNF/IFNγ, but that rather, broad-spectrum MMP inhibitors will be required. [Mol Cancer Ther 2007;6(9):2563–71]
Apoptosis-inducing antitumor efficacy of hexokinase II inhibitor in hepatocellular carcinoma
Authors: Kim Won , Yoon Jung-Hwan , Jeong Jae-Min , Cheon Gi-Jeong , Lee Tae-Sup , Yang Jong-In , Park Su-Cheol , Lee Hyo-Suk
Published: September 2007

Hypoxia stimulates hepatocellular carcinoma (HCC) cell growth via hexokinase (HK) II induction, and alternatively, HK II inhibition induces apoptosis by activating mitochondrial signaling. This study was to investigate whether the induction of HK II by hypoxia is associated with enhanced mitochondrial stability and to confirm the apoptosis-inducing efficacy of HK II inhibitor in an in vivo model of HCC. Mitochondrial stability was examined by treating isolated mitochondria with deoxycholate, a permeability-enhancing agent. Alteration of permeability transition pore complex composition was analyzed by immunoprecipitation and immunoblotting. An in vivo model of HCC was established in C3H mice i.d. implanted with MH134 cells. The antitumor efficacy of i.p. given 3-bromopyruvate (3-BrPA), a HK II inhibitor, was evaluated by measuring tumor volumes and quantifying apoptosis using terminal deoxynucleotidyl transferase–mediated dUTP nick end labeling staining and 99mTc-hydrazinonicotinamide-Annexin V scans. Hypoxia enhanced mitochondrial stability, and this was inhibited by 3-BrPA treatment. In particular, HK II levels in permeability transition pore complex immunoprecipitates were reduced after 3-BrPA treatment. In mice treated with 3-BrPA, mean tumor volumes and tumor volume growth were found to be significantly reduced. Moreover, percentages of terminal deoxynucleotidyl transferase–mediated dUTP nick end labeling–positive cells were significantly increased in 3-BrPA–treated mice, and this apoptosis-inducing efficacy was reflected in vivo by 99mTc-hydrazinonicotinamide-Annexin V imaging. Our results show that hypoxia enhances mitochondrial stability via HK II induction and that HK II inhibitor treatment exhibits an in vivo antitumor effect by inducing apoptosis. Therefore, HK II inhibitors may be therapeutically useful for the treatment of advanced infiltrative hypovascular HCCs, which are growing in a hypoxic environment. [Mol Cancer Ther 2007;6(9):2554–62]
Gambogic acid inhibits the catalytic activity of human topoisomerase IIα by binding to its ATPase domain
Authors: Qin Yuxin , Meng Linghua , Hu Chaoxin , Duan Wenhu , Zuo Zhili , Lin Liping , Zhang Xiongwen , Ding Jian
Published: September 2007

This study is intended to characterize the cellular target of gambogic acid (GA), a natural product isolated from the gamboge resin of Garcinia hurburyi tree, which possesses potent in vitro and in vivo antitumor activities. The antiproliferative activity of GA was further confirmed here in a panel of human tumor cells and multidrug-resistant cells. We found that GA significantly inhibited the catalytic activity of topoisomerase (Topo) II and, to a comparatively less extent, of Topo I, without trapping and stabilizing covalent topoisomerase-DNA cleavage complexes. Down-regulation of Topo IIα but not Topo I and Topo IIβ, reduced GA-induced apoptosis and the phosphorylation of c-Jun, and restored cell proliferation upon GA treatment. Moreover, GA antagonized etoposide-induced DNA damage and abrogated the antiproliferative activity of etoposide, whereas it did not affect camptothecin-induced DNA damage. By dissecting the actions of GA on the individual steps of Topo IIα catalytic cycle, we found that GA inhibited DNA cleavage and ATP hydrolysis. Moreover, GA directly bound to the ATPase domain of Topo IIα, and may share common binding sites with ATP. The results reported here show that GA exerts its antiproliferative effect by inhibiting the catalytic activity Topo IIα. They also indicate that GA inhibits Topo IIα-mediated DNA cleavage and modulate the activity of Topo II poisons, which provide rationale for further clinical evaluation of GA. [Mol Cancer Ther 2007;6(9):2429–40]
The novel melphalan prodrug J1 inhibits neuroblastoma growthin vitroandin vivo
Authors: Wickström Malin , Johnsen John Inge , Ponthan Frida , Segerström Lova , Sveinbjörnsson Baldur , Lindskog Magnus , Lövborg Henrik , Viktorsson Kristina , Lewensohn Rolf , Kogner Per , Larsson Rolf , Gullbo Joachim
Published: September 2007

Neuroblastoma is the most common extracranial solid tumor of childhood. The activity of J1 (l-melphalanyl-p-l-fluorophenylalanine ethyl ester), an enzymatically activated melphalan prodrug, was evaluated in neuroblastoma models in vitro and in vivo. Seven neuroblastoma cell lines with various levels of drug resistance were screened for cytotoxicity of J1 alone or in combination with standard cytotoxic drugs, using a fluorometric cytotoxicity assay. J1 displayed high cytotoxic activity in vitro against all neuroblastoma cell lines, with IC50 values in the submicromolar range, significantly more potent than melphalan. The cytotoxicity of J1, but not melphalan, could be significantly inhibited by the aminopeptidase inhibitor bestatin. J1 induced caspase-3 cleavage and apoptotic morphology, had additive effects in combination with doxorubicin, cyclophosphamide, carboplatin, and vincristine, and synergistically killed otherwise drug-resistant cells when combined with etoposide. Athymic rats and mice carrying neuroblastoma xenografts [SH-SY5Y, SK-N-BE(2)] were treated with equimolar doses of melphalan, J1, or no drug, and effects on tumor growth and tissue morphology were analyzed. Tumor growth in vivo was significantly inhibited by J1 compared with untreated controls. Compared with melphalan, J1 more effectively inhibited the growth of mice with SH-SY5Y xenografts, was associated with higher caspase-3 activation, fewer proliferating tumor cells, and significantly decreased mean vascular density. In conclusion, the melphalan prodrug J1 is highly active in models of neuroblastoma in vitro and in vivo, encouraging further clinical development in this patient group. [Mol Cancer Ther 2007;6(9):2409–17]
Characterization of novel inhibitors of histone acetyltransferases
Authors: Eliseeva Elena D. , Valkov Vassil , Jung Manfred , Jung Mira O.
Published: September 2007

Modification of proteins by histone acetyltransferases (HAT) or histone deacetylases plays an important role in the control of gene expression, and its dysregulation has been linked to malignant transformation and other diseases. Although histone deacetylase inhibitors have been extensively studied and several are currently in clinical trials, there is little information available on inhibitors of HATs (HATi). Starting from the natural product lead HATi anacardic acid, a series of 28 analogues was synthesized and investigated for HAT-inhibitory properties and effects on cancer cell growth. The compounds inhibited up to 95% HAT activity in vitro, and there was a clear correlation between their inhibitory potency and cytotoxicity toward a broad panel of cancer cells. Interestingly, all tested compounds were relatively nontoxic to nonmalignant human cell lines. Western blot analysis of MCF7 breast carcinoma cells treated with HATi showed significant reduction in acetylation levels of histone H4. To directly show effect of the new compounds on HAT activity in vivo, MCF7 cells were cotransfected with the p21 promoter fused to firefly luciferase and a full-length p300 acetyltransferase, and luciferase activity was determined following treatment with HATi. Significant inhibition of p300 activity was detected after treatment with all tested compounds except one. Effects of the new HATi on protein acetylation and HAT activity in vivo make them a suitable tool for discovery of molecular targets of HATs and, potentially, for development of new anticancer therapeutics. [Mol Cancer Ther 2007;6(9):2391–8]
Enterolactone induces apoptosis in human prostate carcinoma LNCaP cells via a mitochondrial-mediated, caspase-dependent pathway
Authors: Chen Li-Hua , Fang Jing , Li Huaixing , Demark-Wahnefried Wendy , Lin Xu
Published: September 2007

The mammalian lignan enterolactone is a major metabolite of plant-based lignans that has been shown to inhibit the growth and development of prostate cancer. However, little is known about the mechanistic basis for its anticancer activity. In this study, we report that enterolactone selectively suppresses the growth of LNCaP prostate cancer cells by triggering apoptosis. Mechanistic studies showed that enterolactone-induced apoptosis was characterized by a dose-dependent loss of mitochondrial membrane potential, release of cytochrome c and cleavage of procaspase-3 and poly(ADP-ribose)-polymerase (PARP). Caspase dependence was indicated by the ability of the pan-caspase inhibitor z-VAD-fmk to attenuate enterolactone-mediated apoptosis. Mechanistic studies suggested roles for Akt, GSK-3β, MDM2, and p53 in enterolactone-dependent apoptosis. Our findings encourage further studies of enterolactone as a promising chemopreventive agent against prostate cancer. [Mol Cancer Ther 2007;6(9):2581–90]
Structural modulation of reactivity/activity in design of improved benzothiophene selective estrogen receptor modulators: induction of chemopreventive mechanisms
Authors: Yu Bolan , Dietz Birgit M. , Dunlap Tareisha , Kastrati Irida , Lantvit Daniel D. , Overk Cassia R. , Yao Ping , Qin Zhihui , Bolton Judy L. , Thatcher Gregory R.J.
Published: September 2007

The benzothiophene selective estrogen receptor modulators (SERM) raloxifene and arzoxifene are in clinical use and clinical trials for chemoprevention of breast cancer and other indications. These SERMs are “oxidatively labile” and therefore have potential to activate antioxidant responsive element (ARE) transcription of genes for cytoprotective phase II enzymes such as NAD(P)H-dependent quinone oxidoreductase 1 (NQO1). To study this possible mechanism of cancer chemoprevention, a family of benzothiophene SERMs was developed with modulated redox activity, including arzoxifene and its metabolite desmethylarzoxifene (DMA). The relative antioxidant activity of these SERMs was assayed and correlated with induction of NQO1 in murine and human liver cells. DMA was found to induce NQO1 and to activate ARE more strongly than other SERMs, including raloxifene and 4-hydroxytamoxifen. Livers from female, juvenile rats treated for 3 days with estradiol and/or with the benzothiophene SERMs arzoxifene, DMA, and F-DMA showed substantial induction of NQO1 by the benzothiophene SERMs. No persuasive evidence in this assay or in MCF-7 breast cancer cells was obtained of a major role for the estrogen receptor in induction of NQO1 by the benzothiophene SERMs. These results suggest that arzoxifene might provide chemopreventive benefits over raloxifene and other SERMs via metabolism to DMA and stimulation of ARE-mediated induction of phase II enzymes. The correlation of SERM structure with antioxidant activity and NQO1 induction also suggests that oxidative bioactivation of SERMs may be modulated to enhance chemopreventive activity. [Mol Cancer Ther 2007;6(9):2418–28]
Effect of Renal Failure on Peak Troponin Ic Level in Patients with Acute Myocardial Infarction
Authors: Mekontso Dessap Armand , Lellouche Nicolas , Audard Vincent , Roudot-Thoraval Françoise , Champagne Stéphane , Lim Pascal , Garot Jerome , Gueret Pascal , Dubois-Randé Jean-Luc
Published: September 2007

Objectives: Peak troponin Ic (cTnI) level could be influenced by renal function. We evaluated the effect of moderate to severe renal failure on peak cTnI level during acute myocardial infarction (AMI). Methods: One hundred and twenty-five consecutive patients admitted to the coronary care unit of a university hospital in France for primary angioplasty during AMI were retrospectively studied. Results: The correlations between peak cTnI level, peak creatine phosphokinase (CK) level, peak cTnI/peak CK ratio and creatinine clearance (CrCl) were assessed. The peak cTnI/peak CK ratio was considered in order to standardize the peak cTnI level with the extent of myocardial necrosis. There was no significant correlation between CrCl and peak CK (r = 0.01, p = 0.95), peak cTnI (r = –0.08, p = 0.38) or the peak cTnI/peak CK ratio (r = –0.14, p = 0.13). There was a trend towards higher peak cTnI in patients with moderate to severe renal failure. The peak cTnI/peak CK ratio did not significantly differ among patients according to CrCl stratification, whereas the ratio of log-transformed values was significantly higher in patients with moderate to severe renal failure. Conclusion: In patients with AMI, the peak cTnI level seemed to be influenced by renal function.