Novel Method for Inducing Tissue Repair
The healing of open wounds or replacement of lost tissue following injury, reconstructive surgery, transplantation or loss of blood supply requires the formation of new blood vessels as well as the growth of organized tissue. At present there are no reproducible procedures to speed up tissue growth, which requires formation of extracellular matrix and collagens by activated fibroblasts, and to induce new blood vessel formation. Recombinant tissue growth factors have been utilized for this purpose with limited success due to their short half-life in vivo, limited penetration into deeper tissue regions, and difficulty in application directly to naturally healing tissue.
Wistar scientists have constructed replication-defective recombinant adenoviruses which express platelet-derived growth factor B (PDGF-B), vascular endothelial growth factor (VEGF) as well as other growth factors. Clinical trials of these vectors to enhance wound healing in diabetic ulcers have been planned; additional applications of the technology, including the use of the vectors in tissue engineering are in development.
Method of Producing a Stem Cell-Like Melanocyte
Wistar scientists have invented a method of producing a dedifferentiated melanocyte, a premelanoma stem cell-like cell, by activating specific intracellular targets and selecting for a stem cell-like melanocyte capable of proliferating under stem cell growth conditions. These dedifferentiated melanocytes increase expression of neural crest-related genes and exhibit a decrease in pigmentation-related genes, compared to untreated controls. Stem cell-like melanocytes are capable of further differentiation into various cell types, assuming neuronal, smooth muscle cell, oligodendrocyte, melanocyte, or chondrocyte phenotypes. Wistar scientists have defined an oncogenic role for Notch signaling in melanocytes and highlight the potential for Notch inhibition to be used as a therapeutic approach for the treatment of melanoma.
Three-Dimensional System to Measure Lymphocyte Migration
There is a need for model systems that can be used to identify clinically relevant behaviors of cytotoxic T lymphocytes (CTL), including tumor cell lysis and active migration, as well as systems that can be used to identify chemokines and tumor antigens that influence active migration of CTL towards tumor cells. Traditionally, CTL are raised and studied in two-dimensional mixed lymphocyte tumor cell culture (MLTC) that includes either (1) long-term cultured tumor cells to stimulate peripheral blood mononuclear cells (PBMC) for CTL induction or (2) disaggregated tumor tissue with tumor infiltrating lymphocytes (TIL) where both types of cultures are two dimensional and are grown directly on plastic surfaces. Studies in melanoma and colon cancer patients have shown that characterization of CTL responses using such two-dimensional cultures do not reflect the CTL’s in vivo behavior and specifically, CTL-exerted anti-tumoral activity.
Wistar scientists have developed a three-dimensional reconstruct model containing solid layers of collagen, tumor cells and CTL that closely mimic the condition of patients in vivo, preserving in vivo semi-phenotypic and functional characteristics of the cells. This model closely mimics CTL behavior in cancer patients and allows the detection of CTL migration and identification of tumor antigens and cytokines/chemokines involved in CTL migration.
Multipotent Adult Stem Cells from Human Hair Follicles
Scientists at The Wistar Institute and the University of Pennsylvania have developed a novel strategy for isolating, growing, and differentiating broadly multipotent adult stem cells from human hair follicles. Adult stem cells, like embryonic stem cells, can differentiate into multiple types of function-dedicated daughter cells, such as nerve or muscle cells. However, most adult stem cells are restricted to producing cell types from only one tissue type (lineage). Researchers at Wistar, in collaboration with researchers at the University of Pennsylvania isolated a unique adult stem cell from human hair follicles, which is capable of producing daughter cells of multiple tissue lineages. The human hair follicle stem cell is a rare, but permanent, inhabitant of the skin follicular microenvironment, and exhibits features that are characteristic of highly-adaptable embryonic stem cells. This technology allows hair follicle stem cells to be collected, maintained in renewable culture, and stimulated to produce daughter cells of multiple classes, including functional skin cells, muscle cells, and nerve cells.
Monoclonal Antibodies Against Wilms' tumor (WT1)
Scientists at The Wistar Institute have created monoclonal antibodies that react with the Wilms' tumor (WT1) protein. These antibodies can be used diagnostically in a variety of malignancies that over-express the WT1 protein. In particular, they can be used for distinguishing mesotheliomas from other tumors or nonmalignant conditions that affect the pleura. In addition, the antibodies may be used to monitor disease activity in acute leukemias.
The wt1 gene was originally identified as a candidate tumor suppressor gene by researchers investigating the causes of Wilms' tumor, a childhood kidney tumor. The gene codes for the WT1 protein, which has the structural features of a DNA-binding transcription factor. The WT1 protein has been shown to be over-expressed in a variety of tumors.
Three monoclonal antibodies have been developed, designated 6F-H2, 6F-H7, 6F-H17, and the isotype for each is IgG1.
The hybridomas producing these antibodies resulted from the fusion of spleen cells from mice immunized with a peptide comprising the N-terminal 173 amino acids of the WT1 protein and cells of the myeloma fusion partner P3x63AG8/653. This N-terminal region of the WT1 protein has little sequence homology to any other known protein. The resulting antibodies do not cross react with other transcription factors containing the zinc finger motif. Consequently, these monoclonal antibodies are more specific than either polyclonal or monoclonal antibodies to WT1 that have been produced by other researchers.
Monoclonal Antibodies that Bind to Nerve Growth Factor Receptor (NGFR)(ME20.4 and ME82.11)
Nerve growth factor is important for regulation of development of sympathetic and sensory neurons and other neural crest-derived cell types. MAbs ME20.4 and ME82.11 bind to the low affinity NGFR of human origin. Using these MAbs, we have carefully defined the biochemical nature of the NGF receptor and its distribution among normal and transformed neural crest tissues.
Reference: Ross, et al., Characterization of nerve growth factor receptor inneural crest tumors using monoclonal antibodies, Proc. Natl. Acad. Sci. 81: 6681-6685, 1984
Monoclonal Antibodies Against bFGF
Wistar scientists have developed two MAbs (designated 8 and 11) against bFGF (basic fibroblast growth factor), which is a major mitogen for cells of various embryological origin. It is important for development, tissue regeneration, cancer, and inflammatory diseases. Its detection is highest in activated tissues. In certain cancer such as melanomas, bFGF is an autocrine growth factor. Neutralization of its activity leads to cessation of growth.
Reference: Mark Nesbit, Heike KE Nesbit, Jean Bennett, Thomas Andl, Mei-Yu Hsu, Emma Dejesus, Michelle McBrian, Abha R. Gupta, Stephen L. Eck, Meenhard Herlyn (1999) "Basic fibroblast growth factor induces a transformed phenotype in normal human melanocytes" Oncogene Vol 18, 6469-6476
Monoclonal Antibody A32 Against MEL-CAM/MUC18
Cell surface melanoma-associated antigens can mediate cell-cell or cell-substrate adhesion, signal transduction, proteolysis, or immune recognition and play a key role in determining invasive and metastatic competence of the tumor cells. MAb A32 binds to endothelial and melanoma cells and detects a 113 Kd cell surface adhesion receptor of the immunoglobulin supergene family. The Mel-CAM/MUC18 antigen is a cell surface molecule involved in heterotypic adhesion. The ligand for Mel-CAM/MUC18 has not yet been identified. Its characterization will be important for endothelial cell adhesion during inflammation.
Monoclonal Antibody 452 Against Aminopeptidase N (CD13)
Anti-Human Tenascin Monoclonal Antibodies 300-1, 300-3, 300-2, 302-1, 302-9
Monoclonal Antibody SAP for the Detection of the ß3 Subunitof the Vitronectin Receptor