Intravenous Delivery of Liposome‐mediated Nonviral DNA Is Less Toxic than Intraperitoneal Delivery in Mice

Abstract

Suicide gene therapy has been shown to be an effective means of destroying pancreatic cancer cells. Liposomes have been described as having better efficacy in gene delivery, and an advantage of using liposomes as gene carriers is that they can be used repeatedly in vivo. The objective of this study is to compare the effect of gene delivery routes and to determine whether systemic delivery of the rat insulin promoter (RIP)-directed suicide gene construct would permit cell-specific gene delivery in vivo. Severe combined immunodeficient (SCID) mice were injected with liposome-RIP-TK (thymidine kinase) complex by either the intraperitoneal or the intravenous route. Twenty-four hours post gene delivery, mice received ganciclovir (GCV) treatment twice daily for 14 days. Mice were sacrificed at various time points. Complete necropsy and serum chemistry analysis were performed. Islet morphology was determined using hematoxylin and eosin (H&E) staining. Serum glucose and insulin levels were also determined. To determine the toxic effect on pancreatic islet cells, immunostaining of insulin-producing and glucagon-producing cells was carried out at each time point. H&E staining indicated that both intravenous and intraperitoneal liposome-RIP-TK gene expression had no effect in normal endocrine islet cells. Both gene-delivery routes in mice resulted in normal glycemia and serum insulin levels. The endocrine islets were intact, with a normal distribution pattern of insulin-producing beta cells and glucagon-secreting alpha cells. However, serum chemistry analysis revealed significantly elevated levels of liver enzymes; suggesting that possible liver damage had occurred with the intraperitoneal gene delivery of liposome-pRIP-TK. Intravenous liposome-mediated gene delivery had no effect on liver enzyme levels. Liposome-mediated gene delivery via intravenous injection was less toxic than intraperitoneal delivery. This gene-delivery route requires fewer liposome-DNA complexes and maintains normal liver function. Thus, intravenous delivery of gene therapy would be superior to intraperitoneal administration of gene therapy in mice.

Enhanced Cytotoxicity of RIPTK Gene Therapy of Pancreatic Cancer via PDX-1 Co-Delivery

“…Our previous studies have also demonstrated that rat insulin promoter (RIP) directed lacZ-reporter gene was express in PDX-1 producing cells such as PANC-1 cell, whereas a low expression level was detected in cell lines that produce low levels of PDX-1 proteins such as MIA PaCa2 cells. A significant cytotoxic effect of RIPTK-mediated gene therapy on PDX-1-positive cells was also found in the studies from our laboratory [26,30,45]. These studies indicate that PDX-1 protein is a crucial activator for RIP-directed gene therapy [26,30,46,47].…”

“…Our group has been using the rat insulin promoter to treat insulinoma and human pancreatic cancer cell line [26,30,45,47]. Our results have shown that RIPTK/GCV gene therapy with liposomal delivery system is not only able to ablate insulinoma and PANC-1 cancer cells in SCID mice, but also leads to normal glycemic controls in animal models although beta cells were not affected in these studies.…”

“…However, not every pancreatic cancer cell line expresses adequate levels of PDX-1 proteins [26,42,45]. To enhance the RIP-directed gene expression in those cells with minimal levels of endogenous PDX-1 protein expression, we introduced exogenous PDX-1 proteins using liposome transfection method.…”

PDX-1 Acts as a Potential Molecular Target for Treatment of Human Pancreatic Cancer

“…66 The low immunogenicity potential allows for repeated injections which are necessary to achieve maximum and longterm gene expression in vivo. 52 This strategy has previously been used in a clinical trial of primary and disseminated human lung cancers by multiple monthly systemic treatments of a tumor suppressor gene using the same liposome vector as used in this study.…”

Functional analysis of the role of glutathione peroxidase (GPx) in the ROS signaling pathway, hyphal branching and the regulation of ganoderic acid biosynthesis in Ganoderma lucidum

“…Oxidants stimulate the generation of Ca 2+ signals in part through the activation of calcium channels in both mammalian cells and in plants, and these signals activate a series of biological and physiological processes (Foreman et al, 2003;Wang et al, 2005). Nox-generated ROS activates Ca 2+ signaling in G. lucidum (Mu et al, 2014).…”