Direct gene transfer with DNA-liposome complexes in melanoma: expression, biologic activity, and lack of toxicity in humans.

Abstract

Direct gene transfer offers the potential to introduce DNA encoding therapeutic proteins to treat human disease. Previously, gene transfer in humans has been achieved by a cell-mediated ex vivo approach in which cells from the blood or tissue of patients are genetically modified in the laboratory and subsequently returned to the patient. To determine the feasibility and safety of directly transferring genes into humans, a clinical study was performed. The gene encoding a foreign major histocompatibility complex protein, HLA-B7, was introduced into HLA-B7-negative patients with advanced melanoma by injection of DNA-liposome complexes in an effort to demonstrate gene transfer, document recombinant gene expression, and determine the safety and potential toxicity of this therapy. Six courses of treatment were completed without complications in five HLA-B7-negative patients with stage IV melanoma. Plasmid DNA was detected within biopsies of treated tumor nodules 3-7 days after injection but was not found in the serum at any time by using the polymerase chain reaction. Recombinant HLA-B7 protein was demonstrated in tumor biopsy tissue in all five patients by immunochemistry, and immune responses to HLA-B7 and autologous tumors could be detected. No antibodies to DNA were detected in any patient. One patient demonstrated regression of injected nodules on two independent treatments, which was accompanied by regression at distant sites. These studies demonstrate the feasibility, safety, and therapeutic potential of direct gene transfer in humans.

Liposome-mediated gene transfer into human basal cell carcinoma

“…It was shown that DNA or DNA lipoplexes can mediate gene transfer into tissues and facilitate gene expression locally at higher concentrations. 17,18,28 The expression of IFNs can, in the case of BCC, be achieved locally and may help to avoid systemic effects. Because these studies were performed in immunodeficient recipients, the mechanism was presumably nonimmune.…”

“…Nonviral gene delivery, and subsequent uptake by cells in vivo, has been described and proven to be a valid methodological approach. 17,18 The advantage of a nonviral gene transfer is that the different components are stored stably for long periods of time and do not represent a significant biological hazard. This approach can potentially also be applied to other skin diseases.…”

“…Different amounts of plasmid DNA or DNA lipoplexes were injected intratumorally, and CAT activity was determined. Cationic liposome-mediated gene transfer has been used previously to transduce numerous primary animal and tumor cells successfully, 18,19 but this method has not been evaluated in BCC. The inclusion of DMRIE/DOPE, which allows formation of DNA lipoplexes, increased detectable CAT activity 60-fold ( Figure 2a).…”

“…BCC is an acquired disease related to sun exposure and is accessible for both injectable and topical gene delivery, thus representing an excellent target of study. Successful transfer and expression of genes by injection into human skin tumors such as melanoma have previously been reported, [17][18][19] but this approach has not been well-explored for BCC. Potentially, delivery of appropriate genes into BCC could be used to achieve sustained protein expression locally, thus offering an alternative to surgery or multiple injections of recombinant IFN-␣2.…”

Co-polymer of histidine and lysine markedly enhances transfection efficiency of liposomes

“…Cationic liposomes are the most commonly used nonviral delivery system for delivery of plasmids into cells in vitro [1][2][3] and in vivo. [4][5][6] A significant problem associated with cationic liposomes is their low in vivo transfection efficiency, 7,8 possibly due to inactivation of the liposomes by serum. 9,10 Despite this limitation, cationic liposome carriers have several major advantages such as relative ease of large-scale production and minimal toxicity.…”