Cancer gene therapy by IL-12 gene delivery using liposomal bubbles and tumoral ultrasound exposure
ABSTRACT Interleukin-12 (IL-12) gene therapy is expected to be effective against cancers because it primes the immune system for cancer cells. In this therapy, it is important to induce IL-12 gene expression in the tumor tissue. Sonoporation is an attractive technique for developing non-invasive and non-viral gene delivery systems, but simple sonoporation using only ultrasound is not an effective cancer gene therapy because of the low efficiency of gene delivery. We addressed this problem by combining ultrasound and novel ultrasound-sensitive liposomes (Bubble liposomes) which contain the ultrasound imaging gas perfluoropropane. Our previous work showed that this is an effective gene delivery system, and that Bubble liposome collapse (cavitation) is induced by ultrasound exposure. In this study, we assessed the utility of this system in cancer gene therapy using IL-12 corded plasmid DNA. The combination of Bubble liposomes and ultrasound dramatically suppressed tumor growth. This therapeutic effect was T-cell dependent, requiring mainly CD8(+) T lymphocytes in the effector phase, as confirmed by a mouse in vivo depletion assay. In addition, migration of CD8(+) T cells was observed in the mice, indicating that the combination of Bubble liposomes and ultrasound is a good non-viral vector system in IL-12 cancer gene therapy.
- SourceAvailable from: Ine Lentacker
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- "To solve this problem, several papers report on the so-called nanobubbles  , also named 'bubble liposomes' , which are smaller than 1 μm, combining the benefits of a liposome (small size, long circulation time) with ultrasound responsiveness. These small bubbles are generally prepared by sonicating liposomes in the presence of fluorinated gases. "
ABSTRACT: Time and space controlled drug delivery still remains a huge challenge in medicine. A novel approach that could offer a solution is ultrasound guided drug delivery. “Ultrasonic drug delivery” is often based on the use of small gas bubbles (so-called microbubbles) that oscillate and cavitate upon exposure to ultrasound waves. Some microbubbles are FDA approved contrast agents for ultrasound imaging and are nowadays widely investigated as promising drug carriers. Indeed, it has been observed that upon exposure to ultrasound waves, microbubbles may (a) release the encapsulated drugs and (b) simultaneously change the structure of the cell membranes in contact with the microbubbles which may facilitate drug entrance into cells. This review aims to highlight (a) major factors known so far which affect ultrasonic drug delivery (like the structure of the microbubbles, acoustic settings, etc.) and (b) summarizes the recent preclinical progress in this field together with a number of promising new concepts and applications.Journal of Controlled Release 12/2012; 164(3):248-55. DOI:10.1016/j.jconrel.2012.08.014 · 7.26 Impact Factor
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- "For example, the transgene expression of luciferase plasmid in the posterior heart after US-mediated transfection peaked at Day 4 but dropped to less than one tenth of the peak value at Day 14 . In one case, the half period of luciferase expression after gene transfection with bubble liposomes and US in mice was only 0.54 days and the luciferase activity was less than 1% at Day 7 . Previous research has shown that cationic polymers such as polyethylenimine (PEI) could enhance the efficiency (and potentially also the expression duration) of both in vitro and in vivo gene transfection. "
ABSTRACT: Ultrasound (US) irradiation has been found to facilitate the inward transport of genetic materials across cell membranes (sonoporation). However, its transfection efficiency is generally low, and the expression duration of transfected gene is short. Polyethylenimine (PEI), a cationic polymer, has been shown to aggregate plasmid DNA and facilitate its internalization. The purpose of this study is to determine whether PEI can also prolong the expression duration after US-mediated transfection. A mixture of pCMViLUC and 22-kDa linear PEI was transfected to cultured cells or mouse muscle by exposure to 1-MHz pulsed US. The duration of expression was assessed periodically following US treatment. As expected, strong expression of luciferase could be found 30days after the treatment of DNA-PEI complex with US exposure, both in vitro and in vivo. However, without US, only very low transfection level could be obtained in vivo. The DNA/PEI complex showed protective effect against digestion of DNase I enzymes as compared with groups without PEI or to which PEI was added following the mixing of plasmid DNA with DNase I. PEI enhanced the US transfection efficiency by increasing both the intracellular uptake of plasmid DNA and the percentage of transfected cells. Most of the DNA uptake occurred at 3h after US exposure, suggesting that endocytosis took place. Moreover, the PEI-facilitated US gene transfection depended on the ratio of PEI and DNA (N/P ratio), which was different for in-vitro and in-vivo conditions. This system could be applied in future human gene therapies.Journal of Controlled Release 03/2012; 160(1):64-71. DOI:10.1016/j.jconrel.2012.03.007 · 7.26 Impact Factor
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- "Liposomes have been known as drug, antigen, and gene delivery carriers     . To solve the above-mentioned issues of microbubbles, we previously developed polyethylene glycol-(PEG-) modified liposomes entrapping echo contrast, bubble liposomes (BL), which can function as a novel gene delivery tool by applying them with US exposure      . "
ABSTRACT: Recently, we have developed novel polyethylene glycol modified liposomes (bubble liposomes; BL) entrapping an ultrasound (US) imaging gas, which can work as a gene delivery tool with US exposure. In this study, we investigated the usefulness of US-mediated gene transfer systems with BL into synoviocytes in vitro and joint synovium in vivo. Highly efficient gene transfer could be achieved in the cultured primary synoviocytes transfected with the combination of BL and US exposure, compared to treatment with plasmid DNA (pDNA) alone, pDNA plus BL, or pDNA plus US. When BL was injected into the knee joints of mice, and US exposure was applied transcutaneously to the injection site, highly efficient gene expression could be observed in the knee joint transfected with the combination of BL and US exposure, compared to treatment with pDNA alone, pDNA plus BL, or pDNA plus US. The localized and prolonged gene expression was also shown by an in vivo luciferase imaging system. Thus, this local gene delivery system into joint synovium using the combination of BL and US exposure may be an effective means for gene therapy in joint disorders.04/2011; 2011(2090-3014):203986. DOI:10.1155/2011/203986