Much of our early work used in cells from individuals with inherited diseases with defective DNA repair and replication genes and with a predisposition for cancer. In addition, we have used this information used these principles that we obtained to generate immortalized cell lines in different stages neoplastic progression to study cancer progression and other inherited diseases such as cystic fibrosis, fragile-X syndrome, and xeroderma pigmentosum, and Fanconi anemia. We have also developed sequence specific gene targeting strategy based on cell-mediated specific modifications of genomic DNA small DNA fragments (SDFs).
This strategy, small fragment homologous replacement (SFHR), was applied to cystic fibrosis (CF) and sickle cell disease (SCD) as well as other inherited diseases. Recent studies have involved the isolation and modification of hematopoietic stem cells as well as the development and characterization of induced pluripotent stem cells (embryonic and induced) as a cell and gene therapy for diseases such as CF and SCD. Studies on the development and differentiation of pluripotent cells for the treatment of endocrine (e.g., thyroid and parathyroid, breast, and pancreas) and hematopoietic disease are an ongoing interest of the laboratory.
Studies to define SFHR and have led to a new paradigm for viewing homologous replacement in human cells. This research has broadened the understanding the mechanistic underpinnings of homologous replacement in human somatic cells. This work has also led us to pursue investigations into the development of transgenic large animal models of disease.
Studies have also focused on non-viral delivery systems ranging from liposomes, polyamidoamines, polyethyleneimines, microinjection, and electroporation for in vitro, in vivo and ex vivo DNA delivery. These studies are critical for identifying viable alternatives to the virally-based approaches for therapeutically delivering DNA into cells and tissue.
Cancer Gene Therapy
Studies to evaluate the role of connexins in “bystander killing” observed with suicide genes have been undertaken in human epithelial cells and in brain tumor cells. As an outgrowth of this work, connexin genes in both transformed and non-transformed cells have been studied to characterize the role of intercellular communication in modulating neoplastic progression. Cell lines will also be developed from tissue samples head and neck cancers (e.g., endocrine, salivary, squamous) to evaluate the molecular genetic features of specific tumor types and their sensitivity to therapeutic agents.
Development of Breast Cancer Therapeutic Strategies
Studies have begun to develop a combined therapy based on the killing of hypoxic cells using suicide gene and shRNA inhibition of VEGF. These systems will be evaluated in vitro and in vivo for their ability to enhance the effectiveness of tumor cell killing. In addition, poly (ADP-ribose) polymerase inhibitor (PARPi) sensitivity and resistance in BRCA2 mutant mammary cells is being evaluated in primary and tumor-derived mammary epithelial cells as well as somatic cell derived iPS cells.
Epithelial Cell and Molecular Biology/Cell Transformation
The generation and characterization of immortalized cell lines for human genetic disorders and cancer is ongoing. The cells lines are tools to investigate biological pathways associated with various diseases and to develop therapeutic strategies. The cell lines developed in my laboratory have been used internationally to elucidate the cellular and genetic mechanisms that underlie human airway epithelial cell biology and disease pathology, genetic disorders, and cancer biology.
Stem Cell-Based Tissue Repair
Studies have been undertaken to evaluate the patient-specific therapeutic potential of adult and pluripotent (embryonic and induced) stem cells. In addition, induced pluripotent stem (iPS) cells from CF and SCD individuals have been generated. Enrichment and the determinants for multilineage differentiation are now under investigation. These studies are of particularly relevant for the repair of organ damage caused by a chronic (genetic or non-genetic), an acute traumatic episode, or therapeutic surgery for tumor removal.
Meet Our Team
R Geoffrey Sargent, PhD
Michael J Yezzi, PhD
Staff Research Associate
Albert C Lee, BA
Post-graduate Research Assistant
Lindsay A Juarez, BS
Post-graduate Research Assistant