Long-term toxicity study of rAd5-hTERTC27 in SD rats and Cynomolgus monkeys by intravenous injection.

rAd5-hTERTC27, a replication-defective adenovirus vector carrying hTERTC27, has been proposed for possible use against hepatocellular carcinoma (HCC). In this study, we investigated the long-term toxicity of rAd5-hTERTC27 in SD rats and Cynomolgus monkeys. rAd5-hTERTC27 was administered intravenously once a week for 13 weeks followed by a one-month recovery period. As of 4 months, all animals displayed overall good health. Anti-adenoviral antibodies emerged in a dose-independent manner. The levels of complement components, C3 and C4, in the rAd5-hTERTC27 middle-dose and high-dose groups and C4 in the rAd5-EGFP group increased significantly after the 2nd treatment in monkeys. Slight-mild pathological changes of the liver occurred only in the rAd5-hTERTC27 high-dose group (2/16) in rats and not in any other group in either rats or monkeys. With the increase of the dose, the incidence of lymphocyte depletion in the spleen of rats and reactive hyperplasia of the splenic corpuscle in monkeys increased. However, the changes in the liver and spleen were reversible. Given the above data, intravenous administration of rAd5-hTERTC27 (up to 4×10(10)VP/kg in rats and 0.9×10(10)VP/kg in monkeys) appears to be well-tolerated, providing support for its potentially safe use in clinical trials for the treatment of HCC.

OX26/CTX-conjugated PEGylated liposome as a dual-targeting gene delivery system for brain glioma.

BACKGROUND: The successful gene delivery into the brain is a major challenge due to the presence of the blood-brain barrier (BBB). In order to transport plasmid DNA across the BBB and target the brain glioma, the PEGylated liposomes (PLs) modified with OX26 and chlorotoxin (CTX) were developed as a dual-targeting gene delivery system, and the therapeutic efficacy of OX26/CTX-PL/pC27 against glioma was evaluated using in vitro and in vivo experimental models. METHODS: The PEGylated liposome complexes were prepared by the reverse phase evaporation method, and their physicochemical properties were examined. The transfection efficiency, intracellular distribution, in vitro effects of OX26/CTX-PL/pC27 were determined on C6, F98 and HEK293T cell lines. The dual-targeting therapeutic efficacy of OX26/CTX-PL/pC27 against glioma were assessed using the BMVECs/C6 cells co-culture model and the rat orthotopic glioma model. RESULTS: The OX26/CTX-PL/pDNA complexes exhibited a subglobose shape, and possessed notably low toxicities to HEK293T and C6 cells post 4 h incubation. In the in vitro transfection experiment, gene expressions of hTERTC27 from C6 and F98 cells were significantly improved by OX26 and CTX modification. Our in vitro results also showed that OX26 endowed the PLs with the transport ability across the BBB. Using the BMVECs/C6 cells co-culture model, the viability of C6 cells was decreased to 46.0% after OX26/CTX-PL/pC27 transfection. The OX26/CTX-PL/pC27 complexes exhibited enhanced therapeutic effects on C6 cells. Moreover, the dual-targeting therapeutic effects were further conformed with diminished tumor volumes (18.81 ± 6.15 mm³) and extended median survival time (46 days) in C6 glioma-bearing rats. Immunohistochemical analysis revealed the therapeutic effects derived from enhanced hTERTC27 expression in the tumor site. CONCLUSIONS: The PEGylated liposomes modified with OX26 and CTX are able to significantly promote cell transfection, increase the transport of plasmid DNA across the BBB and afterwards target the brain glioma cells in vitro and in vivo, exhibit the most significant therapeutic efficacy. The ligand OX26 plays a critical role in transporting the lipoplexes across the BBB, and CTX acts as a major role in targeting brain glioma cells. The results would encourage further developments for non-invasive targeting therapy of brain gliomas by intravenous injection.

Preclinical safety evaluation of rAd5-hTERTC27 by intravenous injection.

The safety of rAd5-hTERTC27, a replication defective adenovirus vector carrying hTERTC27 for possible use against hepatocellular carcinoma (HCC) was assessed. In single-dose evaluations, intravenous dose levels of up to 2×10(11)VP/kg in rats and 9×10(10)VP/kg in monkeys were well tolerated with no abnormal changes in general signs, body weight and food consumption, and no significant differences in biochemical parameters, urinalysis, ECG, and systemic necropsy observations between the rAd5 groups and solvent control group except that slight hematological change was observed. No hemolytic effect using rabbit blood, local perivasculitis following intravenous injection in rabbits or systemic anaphylaxis in guinea pigs following intravenous dosing was seen. No effects on the central nervous system of mice occurred following intravenous dosing with the exception of an increase in sleep duration at the dose of 1.2×10(11)VP/kg (p<0.05) but not at lower doses of 2×10(10) and 6×10(10)VP/kg in the hypnotic synergism test. These results demonstrate that administration of rAd5-hTERTC27 was well tolerated in an initial set of safety studies as part of an evaluation to allow human trials for the treatment of HCC.