[Development of site specific gene delivery system with sonoporation]

Sonodelivery in Skeletal Muscle: Current Approaches and Future Potential

There are currently multiple approaches to facilitate gene therapy via intramuscular gene delivery, such as electroporation, viral delivery, or direct DNA injection with or without polymeric carriers. Each of these methods has benefits, but each method also has shortcomings preventing it from being established as the ideal technique. A promising method, ultrasound-mediated gene delivery (or sonodelivery) is inexpensive, widely available, reusable, minimally invasive, and safe. Hurdles to utilizing sonodelivery include choosing from a large variety of conditions, which are often dependent on the equipment and/or research group, and moderate transfection efficiencies when compared to some other gene delivery methods. In this review, we provide a comprehensive look at the breadth of sonodelivery techniques for intramuscular gene delivery and suggest future directions for this continuously evolving field.

Ultrasound activates ataxia telangiectasia mutated- and rad3-related (ATR)-checkpoint kinase 1 (Chk1) pathway in human leukemia Jurkat cells

Low-intensity ultrasound (US) has been shown to induce death of cancer cells; however, the underlying mechanism remains unclarified. Here, we provide novel evidence that the inhibition of checkpoint kinase 1 (Chk1) by a selective inhibitor or small interfering RNA (siRNA) enhances US-induced apoptosis in Jurkat cells. Jurkat cells showed insignificant lysis immediately after US at any applied intensity, whereas approximately 70% of the cells were γH2AX-positive 30min after US at 0.4W/cm(2). Regarding DNA damage response (DDR), Chk1, known as a target of ataxia telangiectasia mutated (ATM) and rad3-related (ATR), was phosphorylated in cells after US exposure. An ATM inhibitor showed nearly no effect on Chk1 phosphorylation, whereas chemicals showing the ATR inhibitory effect markedly abrogated the phosphorylation, indicating that Chk1 phosphorylation is preferentially more dependent on ATR than on ATM in cells exposed to US. The pharmacological inhibition of Chk1 promoted caspase-3 cleavage and increased the percentage of cells in SubG1 after US exposure. siRNA targeting Chk1 abrogated approximately 55% of Chk1 expression and also promoted apoptosis, suggesting that Chk1 plays anti-apoptotic roles in response to US. These findings revealed, for the first time, that US activates Chk1 dependently on ATR and the activated Chk1 is involved in apoptosis of cells exposed to US. Moreover, we propose that Chk1 may be a promising target in US-aided therapy.

Sonoporation delivery of interleukin-27 gene therapy efficiently reduces prostate tumor cell growth in vivo

We have examined the potential of a novel cytokine, interleukin-27 (IL-27), for gene therapy of prostate cancer. IL-27 is the most recently characterized member of the family of heterodimeric IL-12-related cytokines and has shown promise in halting tumor growth and mediating tumor regression in several cancer models. In the present study, we examined the efficacy of a new mode of gene delivery to prostate tumors: low-frequency ultrasound irradiation or "sonoporation." We also examined the potential of IL-27 gene delivery by sonoporation to treat and reduce the growth of prostate cancer in vivo. We used three models of immune-competent prostate adenocarcinoma and characterized the tumor-growth reduction, gene-profile expression, and effector cellular profiles. Our results suggest that IL-27 can be effective in reducing tumor growth and can help enhance accumulation of effector cells in prostate tumors in vivo. These results are promising, because they are potentially relevant to developing novel therapies that can be translated by using the novel and effective sonoporation gene-therapy delivery strategy.