ABSTRACT
Most patients with advanced breast cancer develop osteolytic bone metastases, which have numerous complications. Because current therapies are not curative, new treatments are needed. Conditionally replicating adenoviruses (CRAds) are anticancer agents designed to infect and lyse tumor cells. However, in spite of their promise as selective cancer therapeutics, replicating adenoviruses have shown limited efficacy in the clinical setting. We hypothesized that a CRAd armed with osteoprotegerin (OPG) would eradicate bone metastases of breast cancer both directly, by oncolysis, and indirectly, by inhibiting osteoclastic bone resorption, and thus reducing the tumor burden. We constructed an armed CRAd (Ad5-Δ24-sOPG-Fc-RGD) by replacing viral E3B genes with a fusion of the ligand-binding domains of OPG and the Fc portion of human IgG1. Conditional replication was conferred by a 24-base pair deletion within E1A (Δ24), which prevents the binding of E1A to the retinoblastoma tumor suppressor/cell cycle regulator protein and limits replication in normal cells. Enhanced infection of cells expressing low levels of the primary Ad5 receptor was conferred by incorporating an arginine-glycine-aspartic acid (RGD) peptide sequence into the fiber knob to mediate binding to α(v) integrins. After characterization of the armed CRAd, we demonstrated that infection of breast cancer cells by Ad5-Δ24-sOPG-Fc-RGD both killed the infected cells by oncolysis and inhibited the formation of osteoclasts in an in vitro co-culture model. In a murine model of osteolytic bone metastases of breast cancer, the CRAd armed with shortened OPG (sOPG)-Fc reduced tumor burden in the bone and inhibited osteoclast formation more effectively than an unarmed CRAd.
Subject(s)
Adenoviridae/genetics , Bone Neoplasms/secondary , Breast Neoplasms/therapy , Osteoprotegerin/genetics , Animals , Bone Neoplasms/pathology , Breast Neoplasms/genetics , Breast Neoplasms/pathology , Carrier Proteins/genetics , Carrier Proteins/metabolism , Cell Line, Tumor , Female , Humans , Mice , Osteoprotegerin/metabolism , Tumor Burden/genetics , Virus ReplicationABSTRACT
Angiogenesis, or neovascularization, is known to play an important role in the neoplastic progression leading to metastasis. CD31 or Factor VIII-related antigen (F VIII RAg) immunohistochemistry is widely used in experimental studies for quantifying tumor neovascularization in immunocompromised animal models implanted with transformed human cell lines. Quantification, however, can be affected by variations in the methodology used to measure vascularization including antibody selection, antigen retrieval (AR) pretreatment, and evaluation techniques. To examine this further, we investigated the microvessel density (MVD) and the intensity of microvascular staining among five different human tumor xenografts and a mouse syngeneic tumor using anti-CD31 and F VIII RAg immunohistochemical staining. Different AR methods also were evaluated. Maximal retrieval of CD31 was achieved using 0.5 M Tris (pH 10) buffer, while maximum retrieval of F VIII RAg was achieved using 0.05% pepsin treatment of tissue sections. For each optimized retrieval condition, anti-CD31 highlighted small vessels better than F VIII RAg. Furthermore, the MVD of CD31 was significantly greater than that of F VIII RAg decorated vessels (p<0.001). The choice of antibody and AR method has a significant affect on immunohistochemical findings when studying angiogenesis. One also must use caution when comparing studies in the literature that use different techniques and reagents.
Subject(s)
Immunohistochemistry/methods , Neoplasms/blood supply , Neoplasms/pathology , Neovascularization, Pathologic/metabolism , Transplantation, Heterologous , Animals , Antibodies , Cell Line, Tumor , Factor VIII/chemistry , Factor VIII/immunology , Female , Humans , Mice , Mice, Inbred BALB C , Microvessels/chemistry , Microvessels/pathology , Neovascularization, Pathologic/immunology , Neovascularization, Pathologic/pathology , Platelet Endothelial Cell Adhesion Molecule-1/chemistry , Platelet Endothelial Cell Adhesion Molecule-1/immunologyABSTRACT
Malignant glioma continues to be a major target for gene therapy and virotherapy due to its aggressive growth and the current lack of effective treatment. However, these approaches have been hampered by inefficient infection of glioma cells by viral vectors,particularly vectors derived from serotype 5 adenoviruses (Ad5). This results from limited cell surface expression of the primary adenovirus receptor, coxsackie-adenovirus-receptor (CAR), on tumor cells. To circumvent this problem, Ad fiber pseudotyping,the genetic replacement of either the entire fiber or fiber knob domain with its structural counterpart from another human Ad serotype that recognizes a cellular receptor other than CAR, has been shown to enhance Ad infectivity in a variety of tumor types,including human glioma. Here, we have extended the paradigm of genetic pseudotyping to include fiber domains from non-human or"xenotype" Ads for infectivity enhancement of human glioma cell populations. In this study, we evaluated the gene transfer efficiency of a panel of Ad vectors which express one of five different "xenotype"fiber knob domains, including those derived from murine,ovine, porcine and canine species, in both human glioma cell lines as well as primary glioma tumor cells from patients. Adenovirus vectors displaying either canine Ad or porcine Ad fiber elements had the highest gene transfer to both glioma cell lines and primary tumor cells. The correlation between the viral infectivity of modified adenovirus vectors and expression of human CAR and CD46(an adenovirus type B receptor) on the surfaces of tumor cells was also analyzed. Taken together, human adenovirus vectors modified with "xenotype" fiber elements could be excellent candidates to target human glioma.
Subject(s)
Adenoviridae/metabolism , Brain Neoplasms/metabolism , Glioma/metabolism , Animals , Cell Line, Tumor , Constitutive Androstane Receptor , Cytomegalovirus/metabolism , Gene Transfer Techniques , Genetic Therapy/methods , Genetic Vectors , Humans , Membrane Cofactor Protein/metabolism , Mice , Receptors, Cytoplasmic and Nuclear/metabolism , Transcription Factors/metabolism , Viruses/metabolismABSTRACT
This study sought to determine if weekly X-ray exposure affected breast cancer cell metastasis to bone and to also evaluate the use of bioluminescent imaging (BLI) and microSPECT for detection of metastatic bone lesions. Five week old nude mice were randomly assigned to the CT exposed (n = 7) and no CT exposure (n = 6) treatment groups. Mice received an intracardiac injection of MDA-MB-435 human breast cancer cells transduced with luciferase, or a sham injection (saline). The CT exposed group of mice received CT irradiation once a week for 5 weeks. All mice underwent weekly BLI and select mice received Tc-99m-MDP followed by microSPECT imaging after 5 weeks. Pathological evaluation and histomorphometry were used to assess the affect of CT X-rays on bone metastasis and to evaluate BLI. BLI results found no significant difference in metastasis between animals that received CT and those that did not (P > 0.05); however, histomorphometry of the knee joints revealed a significant increase (P = 0.029) in tumor area of the leg bones in mice that received CT exposure (60% +/- 7%) compared to animals that did not receive CT scans (33% +/- 8%). Compared to histological analysis, BLI of the leg and spine was determined to have excellent sensitivity (100%), good specificity (80-90%) and accuracy (90-96%), a positive predictive value of 81-93% and a 100% negative predictive value. Thus, multi-modality imaging techniques can be very useful for monitoring bone metastasis, however microCT X-rays should be used judiciously in order to limit irradiation that may stimulate increased metastasis to specific regions of the skeleton. MicroSPECT imaging did not detect metastatic lesions in the legs of these young nude mice.
Subject(s)
Bone Neoplasms/diagnostic imaging , Mammary Neoplasms, Experimental/pathology , Animals , Bone Neoplasms/secondary , Bone and Bones/pathology , Cell Line, Tumor , Female , Humans , Luminescence , Mice , Mice, Nude , Neoplasm Transplantation , Organ Specificity , Predictive Value of Tests , Random Allocation , Tomography, Emission-Computed, Single-Photon/methods , Tomography, X-Ray Computed/adverse effects , Tomography, X-Ray Computed/methods , Transplantation, HeterologousABSTRACT
Oncolytic viruses represent a novel cancer treatment strategy. Despite their promising preclinical data, however, corresponding clinical trials have disappointed. To aid preclinical analyses, we hypothesized that three-dimensional tumor cell clusters or spheroids might provide an assay system superior to conventional monolayer cell cultures. Spheroids show viral infection, replication and oncolytic patterns distinct from conventional monolayer assays. Therefore, viral tumor penetration and oncolysis measurements may be improved with such three-dimensional models. Also, preclinical analyses of oncolytic viruses frequently measure mitochondrial activity, but more accurate measures of oncolysis might involve quantitation of intracellular protein release. Therefore, we measured luciferase released from luciferase-expressing spheroids and found unique patterns that maintained consistency with various viruses and doses. The relative variations between viruses and doses may represent temporal differences in oncolysis dynamics. Analysis of five recombinant replicative adenoviruses with promise for clinical application showed that Ad5/3-Delta24 produced the most luciferase release 1 week after infection and achieved the earliest and highest peak luciferase release level. Ad5/3-Delta24 also effected the earliest subtotal spheroid cell death. These findings closely parallel monolayer oncolysis assays with these agents. Therefore, the luciferase-expressing tumor spheroid assay represents a promising three-dimensional model for preclinical analysis of replicative oncolytic agents.
Subject(s)
Adenoviridae/physiology , Biological Assay , Luciferases/analysis , Oncolytic Viruses/physiology , Virus Replication , Adenoviridae/genetics , Humans , Luciferases/genetics , Oncolytic Viruses/genetics , Spheroids, Cellular/virology , Tumor Cells, CulturedABSTRACT
This review begins with an introduction to the malignant bone tumor, osteosarcoma [OS] and then moves to a discussion of the commonly used vectors for gene transfer. We first briefly highlight non-viral vectors including polymeric and liposomal delivery systems but concentrate predominantly on the 5 leading viral vectors used in cancer gene therapy, specifically retroviruses, adeno-associated viruses, herpes viruses and lentiviruses with the most detailed analysis reserved for adenoviruses. The 3 main strategies for gene therapy in osteosarcoma are next summarized. As part of this review, the several prodrug-converting enzymes utilized in OS suicide gene therapy are examined. The text then turns to a discussion of adenovirus-mediated gene transfer and the need for tumor targeting via transductional or transcriptional approaches. Because of practical problems with use of replication-incompetent viruses in achieving complete tumor kill in vivo, virotherapy utilizing replication competent viruses has come to the fore. This topic is, thus, next reviewed which allows for a natural transition to a discussion of armed therapeutic viruses many of which are conditionally replicating adenoviruses carrying transgenes with established anti-tumor efficacy. We recognize that several other issues have arisen which hamper progress in the field of cancer gene therapy. We, therefore, review viral-induced toxicity in the host and vector delivery issues which have been found to potentially influence safety. We end with a brief perspective including commenting on animal models used in examining delivery strategies for osteosarcoma gene therapy. The challenges remaining are touched upon most especially the need to deal with pulmonary metastatic disease from OS.
Subject(s)
Bone Neoplasms/therapy , Genetic Therapy/methods , Osteosarcoma/therapy , Genes, Transgenic, Suicide , Genetic Therapy/adverse effects , Genetic Vectors , Humans , Mutation , Oncolytic Virotherapy , Safety , Viruses/geneticsABSTRACT
This is the second part of a two-part review presenting an overview of the molecular findings associated with both benign and malignant chondroid neoplasms. The first part presented a brief review of modern methods in molecular pathology, along with a review of the cytogenetic and molecular genetic findings in benign chondroid neoplasms. This second part reviews the cytogenetic and molecular genetic findings in malignant chondroid neoplasms. Clinical aspects of the various lesions are briefly discussed, and each tumor is illustrated with representative radiographic and pathologic images.
Subject(s)
Bone Neoplasms/genetics , Bone Neoplasms/pathology , Chondrosarcoma/genetics , Chondrosarcoma/pathology , Bone Neoplasms/classification , Chondrosarcoma/classification , HumansABSTRACT
This two-part review presents an overview of the molecular findings associated with both benign and malignant chondroid neoplasms. This first part presents a brief review of methods in molecular pathology along with a review of the cytogenetic and molecular genetic findings in benign chondroid neoplasms. Clinical aspects of the various lesions are briefly discussed, and each tumor is illustrated with representative radiographic and pathologic images. Malignant chondroid neoplasms will be considered in the second part of this review.
Subject(s)
Bone Neoplasms/genetics , Bone Neoplasms/metabolism , Chondroma/genetics , Chondroma/metabolism , Genetic Testing/methods , Biomarkers/metabolism , Bone Neoplasms/diagnosis , Chondroma/diagnosis , Genetic Predisposition to Disease/genetics , HumansABSTRACT
Whereas virotherapy has emerged as a novel and promising approach for neoplastic diseases, appropriate model systems have hampered preclinical evaluation of candidate conditionally replicative adenovirus agents (CRAds) with respect to liver toxicity. This is due to the inability of human viral agents to cross species. We have recently shown the human liver tissue slice model to be a facile means to validate adenoviral replication. On this basis, we sought to determine whether our ex vivo liver tissue slice model could be used to assess CRAd-mediated liver toxicity. We analyzed and compared the toxicity of a conditionally replicative adenovirus (AdDelta24) to that of a replication incompetent adenovirus (Adnull [E1-]) in mouse and human liver tissue slices. To accomplish this, we examined the hepatic apoptosis expression profile by DNA microarray analyses, and compared these results to extracellular release of aminotransferase enzymes, along with direct evidence of apoptosis by caspase-3 immunhistochemical staining and TUNEL assays. Human and mouse liver tissue slices demonstrated a marked increase in extracellular release of aminotransferase enzymes on infection with AdDelta24 compared to Adnull. AdDelta24-mediated liver toxicity was further demonstrated by apoptosis induction, as detected by caspase-3 immunohistochemical staining, TUNEL assay and microarray analysis. In conclusion, concordance of CRAd-mediated apoptosis in both the human and the mouse liver tissue slice models was demonstrated, despite the limited replication ability of CRAds in mouse liver slices. The results of this study, defining the CRAd-mediated apoptosis gene expression profiles in human and mouse liver, may lay a foundation for preclinical liver toxicity analysis of CRAd agents.
Subject(s)
Adenoviridae/genetics , Apoptosis , Genetic Vectors , Liver Neoplasms/virology , Liver/virology , Virus Replication , Animals , Biological Assay , Down-Regulation , Gene Deletion , Humans , Liver/cytology , Mice , Microarray Analysis , Models, Biological , Reverse Transcriptase Polymerase Chain Reaction , Up-RegulationABSTRACT
The full realization of conditionally replicative adenoviruses (CRAds) for cancer therapy has been hampered by the limited knowledge of CRAd function in vivo and particularly in an immunocompetent host. To address this issue, we previously proposed a canine adenovirus type 2 (CAV2)-based CRAd for clinical evaluation in canine patients with osteosarcoma (OS). In this study, we evaluated infectivity-enhancement strategies to establish the foundation for designing a potent CAV2 CRAd with effective transduction capacity in dog osteosarcoma cells. The results indicate that the native CAV2 fiber-knob can mediate increased binding, and consequently gene transfer, in both canine osteosarcoma immortalized and primary cell lines relative to previously reported Ad5 infectivity-enhancement strategies. Gene delivery was further enhanced by incorporating a polylysine polypeptide onto the carboxy terminus of the CAV2 knob. This vector demonstrated improved gene delivery in osteosarcoma xenograft tumors. These data provide the rationale for generation of infectivity-enhanced syngeneic CAV2 CRAds for clinical evaluation in a dog osteosarcoma model.
Subject(s)
Dog Diseases/therapy , Genetic Therapy/methods , Oncolytic Virotherapy/methods , Osteosarcoma/therapy , Transduction, Genetic/methods , Adenoviridae/genetics , Adenoviridae Infections/virology , Animals , Caveolin 2/genetics , Cell Line, Tumor , Dog Diseases/virology , Dogs , Flow Cytometry , Genetic Vectors/administration & dosage , Genetic Vectors/genetics , Humans , Mice , Mice, Nude , Microscopy, Fluorescence , Models, Animal , Neoplasm Transplantation , Osteosarcoma/veterinary , Osteosarcoma/virology , Recombinant Proteins/administration & dosage , Recombinant Proteins/genetics , Transplantation, Heterologous , Virus ReplicationABSTRACT
Calcium entry into myocytes drives contraction of the embryonic heart. To prepare for the next contraction, myocytes must extrude calcium from intracellular space via the Na+/Ca2+ exchanger (NCX1) or sequester it into the sarcoplasmic reticulum, via the sarcoplasmic reticulum Ca2+-ATPase2 (SERCA2). In mammals, defective calcium extrusion correlates with increased intracellular calcium levels and may be relevant to heart failure and sarcoplasmic dysfunction in adults. We report here that mutation of the cardiac-specific NCX1 (NCX1h) gene causes embryonic lethal cardiac arrhythmia in zebrafish tremblor (tre) embryos. The tre ventricle is nearly silent, whereas the atrium manifests a variety of arrhythmias including fibrillation. Calcium extrusion defects in tre mutants correlate with severe disruptions in sarcomere assembly, whereas mutations in the L-type calcium channel that abort calcium entry do not produce this phenotype. Knockdown of SERCA2 activity by morpholino-mediated translational inhibition or pharmacological inhibition causes embryonic lethality due to defects in cardiac contractility and morphology but, in contrast to tre mutation, does not produce arrhythmia. Analysis of intracellular calcium levels indicates that homozygous tre embryos develop calcium overload, which may contribute to the degeneration of cardiac function in this mutant. Thus, the inhibition of NCX1h versus SERCA2 activity differentially affects the pathophysiology of rhythm in the developing heart and suggests that relative levels of NCX1 and SERCA2 function are essential for normal development.
Subject(s)
Calcium/metabolism , Heart/embryology , Heart/physiopathology , Morphogenesis/physiology , Myocardial Contraction/physiology , Zebrafish/embryology , Amino Acid Sequence , Animals , Calcium/pharmacology , Calcium-Transporting ATPases/genetics , Calcium-Transporting ATPases/metabolism , Heart/drug effects , Humans , Microscopy, Electron, Transmission , Molecular Sequence Data , Mutation/genetics , Sarcoplasmic Reticulum Calcium-Transporting ATPases , Sequence Alignment , Sequence Homology, Amino Acid , Sodium-Calcium Exchanger/chemistry , Sodium-Calcium Exchanger/genetics , Sodium-Calcium Exchanger/metabolismABSTRACT
Conditionally replicating adenoviruses (CRADs) take advantage of tumor-specific characteristics for preferential replication and subsequent oncolysis of cancer cells. The antitumor effect is determined by the capability to infect tumor cells. Here, we used RGDCRADcox-2R, which features the cyclooxygenase-2 promoter for replication control and an integrin binding RGD-4C motif for enhanced infectivity of ovarian cancer cells. RGDCRADcox-2R replicated in and killed human ovarian cancer cells effectively, while the replication in nonmalignant cells was low. Importantly, the therapeutic efficacy, as evaluated in an orthotopic model of peritoneally disseminated ovarian cancer, was significantly improved and toxicity was lower than with a wild-type virus. Thus, this CRAD could be tested for treatment of ovarian cancer in humans.
Subject(s)
Adenocarcinoma/therapy , Adenoviruses, Human/genetics , Genetic Therapy/methods , Genetic Vectors/administration & dosage , Isoenzymes/genetics , Ovarian Neoplasms/therapy , Promoter Regions, Genetic , Prostaglandin-Endoperoxide Synthases/genetics , Animals , Cell Death , Cell Line, Tumor , Cyclooxygenase 2 , Female , Humans , Membrane Proteins , Mice , Mice, SCID , Models, Animal , Virus ReplicationABSTRACT
Single chain antibodies (scFv) represent powerful interventional agents for the achievement of targeted therapeutics. The practical utility of these agents have been limited, however, by difficulties related to production of recombinant scFv and the achievement of effective and sustained levels of scFv in situ. To circumvent these limitations, we have developed an approach to express scFv in vivo. An anti-erbB2 scFv was engineered for secretion by eukaryotic cells. The secreted scFv could bind to its target and specifically suppress cell growth of erbB2-positive cells in vitro. Adenoviral vectors expressing the cDNA for the secretory scFv likewise could induce target cells to produce an anti-tumor anti-erbB2 scFv. In vivo gene transfer via the anti-erbB2 scFv encoding adenovirus also showed anti-tumor effects. Thus, by virtue of engineering a secreted version of the anti-tumor anti-erbB-2 scFv, and in vivo expression via adenoviral vector, effective concentrations of scFv were achieved. In vivo gene transfer clearly represents a powerful means to realize effective scFv-based approaches. This method will likely have applicability for a range of disorders amenable to targeted therapeutic approaches.
Subject(s)
Adenoviridae/genetics , Antibodies, Monoclonal/genetics , Genetic Therapy/methods , Genetic Vectors , Receptor, ErbB-2/immunology , Animals , Antibodies, Monoclonal/blood , Female , Gene Targeting/methods , Humans , Mice , Mice, Nude , Neoplasm Transplantation , Ovarian Neoplasms/prevention & control , Transfection , Tumor Cells, CulturedABSTRACT
The sugar alpha-L-fucose is overexpressed in many human malignancies, especially on specific glycoproteins, glycolipids, certain mucins, and putative cell adhesion ligands found on cancer cell surfaces. Many of these molecules are known or suspected mediators of cell-cell adhesion, cell signaling, motility, or invasion. As knowledge of fucose metabolism evolves and specific mechanisms of its distribution and incorporation are more exactly documented, modulation of fucose expression in cancer is becoming increasingly more feasible. The authors propose that cancer cell surface alpha-L-fucose is a logical target for selective therapeutic ablation. Reduction of fucose content on the surfaces of malignant cells should effectively cripple the cells' physiologic functions by altering or dysregulating cell-cell or cell-matrix interactions, critical for maintaining the malignant phenotype. Significant therapeutic benefits might include modulation of adhesion abnormalities in the cancer cells, reduction of cancer cell motility or invasiveness, reexposure to immune surveillance, or a combination of these events.
Subject(s)
Antigens, Surface/metabolism , Biomarkers, Tumor/metabolism , Fucose/metabolism , Neoplasms/metabolism , Biological Transport , Cell Adhesion Molecules/metabolism , Cell Membrane/metabolism , Fucose/analysis , Genetic Therapy , Glycoproteins/metabolism , Humans , Ligands , Mucins/metabolism , Neoplasms/therapyABSTRACT
The adenovirus (Ad) is a useful vector for cancer gene therapy due to its unparalleled gene transfer efficiency to dividing and quiescent cells. Primary cancer cells, however, often have highly variable or low levels of the requisite coxsackie-adenovirus receptor (CAR). Also, assessment of gene transfer and vector persistence has been logistically difficult in human clinical trials. We describe here two novel bicistronic adenoviral (Ad) vectors, AdTKSSTR and RGDTKSSTR, which contain the herpes simplex virus thymidine kinase gene (TK) for molecular chemotherapy and bystander effect. In addition, the viruses contain the human somatostatin receptor subtype-2 gene (SSTR2), the expression of which can be noninvasively imaged. We enhanced the infectivity of RGDTKSSTR by genetically incorporating the RGD-4C motif into the HI-loop of the fiber. This allows the virus to circumvent CAR deficiency by binding to alpha(v)beta(3) and alpha(v)beta(5) integrins, which are highly expressed on most ovarian cancers. The expanded tropism of RGDTKSSTR results in increased infectivity of purified primary ovarian cancer cells and allows enhanced gene transfer in the presence of malignant ascites containing anti-Ad antibodies. RGDTKSSTR may be a useful agent for treating ovarian cancer in clinical trials.
Subject(s)
Adenoviridae/genetics , Adenoviridae/physiology , Diagnostic Imaging/methods , Gene Expression , Genetic Therapy/methods , Ovarian Neoplasms/genetics , Ovarian Neoplasms/therapy , Ascites/genetics , Ascites/metabolism , Ascites/pathology , Ascites/virology , Cell Survival/drug effects , Coxsackie and Adenovirus Receptor-Like Membrane Protein , DNA, Recombinant/genetics , Female , Ganciclovir/pharmacology , Genetic Vectors/genetics , Gentian Violet , HeLa Cells , Humans , Mutagenesis, Insertional , Ovarian Neoplasms/pathology , Ovarian Neoplasms/virology , RNA, Messenger/genetics , RNA, Messenger/metabolism , Receptors, Somatostatin/genetics , Receptors, Virus/metabolism , Reverse Transcriptase Polymerase Chain Reaction , Thymidine Kinase/genetics , Tumor Cells, CulturedABSTRACT
Ovarian carcinoma is a leading cause of cancer death in women. Though advances in conventional therapies have been achieved, long-term survival rates for most patients diagnosed with ovarian cancer are still low. Therefore, novel molecular therapeutic strategies such as gene therapy are being intensively pursued. Such approaches are based on the enormous progress that has been achieved in the elucidation of the molecular foundations of ovarian cancer. In this regard transcriptional control elements (promoters) of genes frequently upregulated or specifically expressed in tumors can be applied in a heterologous context to drive expression of therapeutic genes in targeted gene therapy strategies. This review discusses transcriptional targeting strategies in ovarian cancer gene therapy and gives an overview of tumor-specific promoters (TSPs) that have been applied for this purpose.
Subject(s)
Genetic Therapy/methods , Ovarian Neoplasms/genetics , Ovarian Neoplasms/therapy , Transcription, Genetic/genetics , Animals , Female , Humans , Promoter Regions, GeneticABSTRACT
The Internet has revolutionized the computer and communications world. It has grown to become a worldwide mechanism for information exchange without regard for geographic boundaries. The tremendous growth in this wealth of information poses several questions regarding the utility of this powerful tool in pathology practice and education. This article reviews the advantages and disadvantages of using the Internet in pathology resident education, in general, and how it has impacted the repertoire of educational opportunities at our own institution. The various Internet resources of educational value for pathology trainees are outlined. Basic Internet concepts are also elucidated.
Subject(s)
Computer-Assisted Instruction/methods , Internet/trends , Internship and Residency/methods , Pathology, Clinical/education , HumansABSTRACT
PURPOSE: Relapse remains a significant problem in patients with metastatic osteosarcoma. The response to carboplatin of patients with newly diagnosed metastatic or unresectable osteosarcoma was assessed in an upfront phase II window, which was followed-up by surgery and intensive multiagent chemotherapy. PATIENTS AND METHODS: Thirty-seven patients, ages 3 to 23 years with histologically confirmed diagnoses of osteosarcoma, were treated between January 1992 and November 1994 with carboplatin 1,000 mg/m2 per dose administered as a 48-hour continuous infusion. Two courses were administered in 3-week intervals, depending on marrow recovery. After radiographic reevaluation, patients underwent surgical removal of tumor (if feasible) and then 40 weeks of chemotherapy with high-dose methotrexate, ifosfamide, doxorubicin, and cisplatin. RESULTS: One of the 37 evaluable patients demonstrated a partial response to carboplatin; there were no complete responses. Patients were additionally analyzed by the response of pulmonary metastases to therapy and the extent of tumor necrosis of the primary lesion. By these criteria, 8 of 37 (22%) of patients showed a response at one or more sites, whereas 20 of 37 (54%) had unequivocal disease progression. Severe myelosuppression was the major toxicity. The projected 3-year event-free and overall survival rates were 23.9% and 31.9%, respectively. Only 1 of 17 patients with unresectable disease or distant bone metastases remains alive, in contrast to 6 of 17 patients with the lung as their only metastatic site and two of three patients with resected regional bone metastases. CONCLUSIONS: Continuous-infusion carboplatin demonstrated limited activity as an upfront agent in patients with metastatic osteosarcoma at diagnosis, even at doses that result in severe and prolonged myelosuppression. Patients with isolated pulmonary metastases or resectable bone metastases have a longer median survival time and greater chance of long-term survival than do patients with unresectable bone disease, for whom the prognosis remains dismal.
Subject(s)
Antineoplastic Agents/administration & dosage , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Bone Neoplasms/drug therapy , Carboplatin/administration & dosage , Osteosarcoma/drug therapy , Adolescent , Adult , Antineoplastic Agents/adverse effects , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Bone Neoplasms/secondary , Bone Neoplasms/surgery , Carboplatin/adverse effects , Child , Child, Preschool , Cisplatin/administration & dosage , Cisplatin/adverse effects , Combined Modality Therapy , Doxorubicin/administration & dosage , Doxorubicin/adverse effects , Drug Administration Schedule , Female , Humans , Ifosfamide/administration & dosage , Ifosfamide/adverse effects , Infusions, Intravenous , Male , Methotrexate/administration & dosage , Methotrexate/adverse effects , Osteosarcoma/secondary , Osteosarcoma/surgery , Preoperative Care , Survival Rate , Treatment OutcomeSubject(s)
Sarcoma, Ewing/pathology , Soft Tissue Neoplasms/pathology , Toes , Adolescent , Diagnosis, Differential , Female , HumansABSTRACT
Aggressive osteoblastoma is a rare bone-forming neoplasm composed of prominent epithelioid cells that demonstrate locally invasive growth with a high rate of recurrence but no metastatic potential. Clinical, radiographic and pathologic features of mandibular aggressive osteoblastoma in a 21-year-old African-American male and a 12-year-old Caucasian female are presented. Both tumors were resected with wide surgical margins and neither patient had adjuvant radiation or chemotherapy. The patients showed no evidence of local recurrence or distant spread either clinically or radiographically after two years of follow-up. These tumors were composed of solid sheets of pleomorphic epithelioid cells, eosinophilic amorphous osteoid with foci of calcification, which closely simulated amyloid. Differentiation of this tumor from histologically similar calcifying epithelial odontogenic tumor and low-grade osteosarcoma proved difficult. Immunohistochemical study with osteocalcin confirmed the osteoblastic nature of these epithelioid cells.