Keratinocyte Gene Transfer and Gene Therapy

Abstract

Gene therapy has moved beyond the pre-clinical stage to the treatment of a variety of inherited and acquired diseases. For such therapy to be successful, genes must be efficiently delivered to target cells and gene products must be expressed for prolonged periods of time without toxic effects to the host. This may be achieved by means of an in vivo strategy where genes are transferred directly into a host cell, or by means of an ex vivo approach through which cells are removed, cultured, targeted for gene delivery, and grafted back to the host. Several obstacles continue to delay safe and effective clinical application of gene therapy in a variety of target cells. The limited survival of transplanted cells, transient expression of transferred genes, and difficulties in targeting stem cells are technical issues requiring further investigation.Epidermal and oral keratinocytes are potential vehicles for gene therapy. Several features of these tissues can be utilized to achieve delivery of therapeutic gene products for local or systemic delivery. These qualities include: (1) the presence of stem cells; (2) the cell-, strata-, and site-specific regulation of keratinocyte gene expression; (3) tissue accessibility; and (4) secretory capacity. Such features can be exploited by the use of gene therapy strategies to facilitate: (1) identification, enrichment, and targeting of stem cells to ensure the continued presence of the transferred gene; (2) high-level and persistent transgene expression using keratinocyte-specific promoters; (3) tissue access needed for culture and grafting for ex vivo therapy and direct in vivo gene transfer; (4) secretion of transgene product for local or systemic delivery; and (5) monitoring of genetically modified tissue and removal if treatment termination is required. Optimal gene therapy strategies are being tested in a variety of tissues to treat dominant and recessive genetic disorders as well as acquired diseases such as neoplasia and infectious disease. This experience provides a basis for the application of such clinical studies to a spectrum of diseases effecting epidermal and oral keratinocytes. Gene therapy is in an early stage yet holds great promise for its ultimate clinical application.

Long-Term Culture of Human Gingival Keratinocyte Progenitor Cells by Down-regulation of 14-3-3σ

“…For this reason, we were interested in procedures to isolate, expand, and propagate gingival keratinocyte progenitor cells as stable populations in culture to create a continuous source for the biological characterization of this stem cell compartment as well as for the potential clinical use in treatments targeting the gingival epithelium and for testing the safety of new drugs or oral hygiene products (1).…”

Pharmacological Retention of Oral Mucosa Progenitor/Stem Cells

“…Others have shown the importance of adult stem cells in gene therapy (Garlick and Fenjves, 1996) and regenerative medicine (Mooney and Vandenburgh, 2008) requiring the isolation and/or identification and amplification of a progenitor/stem cell population. Investigators have successfully created tagged or genetically modified long-term oral keratinocyte cell lines for investigational use (Kirschner et al, 2006;Kim et al, 2007); however, the modified cells do not pass the regulatory guidelines of the Food and Drug Administration (FDA) because of their questionable safety.…”

A Study of the Expression of Functional Human Coagulation Factor IX in Keratinocytes Using a Nonviral Vector Regulated by K14 Promoter

“…Hemophilia B is a genetic disease widely prevalent throughout the world, and ex vivo gene therapy could be an alternative approach to challenge such genetically caused systemic diseases [40]. There are a number of evidences that support the application of epidermal keratinocytes as bioreactors for the production and systemic release of proteins [2,4].…”