Ultrasound-Targeted Microbubble Destruction to Deliver siRNA Cancer Therapy

Carson, Andrew R.; McTiernan, Charles F.; Lavery, Lawrence A.; Grata, Michelle; Leng, Xiaoping; Wang, Jianjun; Chen, Xucai; Villanueva, Flordeliza S.

doi:10.1158/0008-5472.can-11-4079

Cited by 145 publications

(125 citation statements)

References 41 publications

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“…Studies using microbubbles driven by ultrasound in the megahertz frequency range have shown initial success in delivering therapeutic payloads in in vitro (6-10) and animal models (11)(12)(13). The delivery efficiency, however, remains inferior to that demonstrated via viral methods (4), in large part due to an incomplete physical, mechanistic understanding of the manner in which acoustic cavitation alters endothelial membrane permeability.…”

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confidence: 99%

Biophysical insight into mechanisms of sonoporation

Helfield

Chen

Watkins

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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This study presents a unique approach to understanding the biophysical mechanisms of ultrasound-triggered cell membrane disruption (i.e., sonoporation). We report direct correlations between ultrasound-stimulated encapsulated microbubble oscillation physics and the resulting cellular membrane permeability by simultaneous microscopy of these two processes over their intrinsic physical timescales (microseconds for microbubble dynamics and seconds to minutes for local macromolecule uptake and cell membrane reorganization). We show that there exists a microbubble oscillation-induced shear-stress threshold, on the order of kilopascals, beyond which endothelial cellular membrane permeability increases. The shear-stress threshold exhibits an inverse squareroot relation to the number of oscillation cycles and an approximately linear dependence on ultrasound frequency from 0.5 to 2 MHz. Further, via real-time 3D confocal microscopy measurements, our data provide evidence that a sonoporation event directly results in the immediate generation of membrane pores through both apical and basal cell membrane layers that reseal along their lateral area (resealing time of ∼<2 min). Finally, we demonstrate the potential for sonoporation to indirectly initiate prolonged, intercellular gaps between adjacent, confluent cells (∼>30-60 min). This real-time microscopic approach has provided insight into both the physical, cavitation-based mechanisms of sonoporation and the biophysical, cell-membrane-based mechanisms by which microbubble acoustic behaviors cause acute and sustained enhancement of cellular and vascular permeability.ultrasound therapy | microbubble contrast agent | endothelial membrane | gene delivery | sonoporation D elivery vehicles for therapeutic nucleic acids (e.g., siRNA, mRNA, plasmids, oligonucleotides), including nanoparticles or viruses, are intended to increase the local effectiveness of the therapeutic within a target tissue while reducing off-target effects. A major barrier to the successful delivery of molecular therapeutics in this manner is the endothelial cell membrane. Viral vectors, although able to efficiently deliver genetic material to target cells via their intracellular trafficking machinery, may elicit specific inflammatory and nonspecific antiviral immune responses (1, 2). As an alternative, nonviral vectors--for example, localized needle injection of naked therapeutic nucleic acids or lipofection--use physical forces or compounds, respectively, to deliver a genetic payload into a cell and are generally less toxic and immunogenic than viral vectors (3). However, direct needle injection into the target poses challenges in achieving homogeneous tissue distribution of the payload (4), and clinical implementation is limited by the impractical requirements of repetitive needle injections into sites which may be difficult to access. Systemically injected liposomes face the endothelial barrier, are vulnerable to intravascular destruction and/or renal excretion (depending on size), and, when endocytosed b...

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confidence: 99%

Biophysical insight into mechanisms of sonoporation

Helfield

Chen

Watkins

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

213

177

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“…9 The acoustic radiation force on the MB has been proposed to deliver biological agents such as stem cells for vascular therapy. 10 The ability of US in the presence of MB to accelerate thrombolysis shows the potential for US therapy for myocardial infarction, stroke, and microvascular repair.…”

Section: Introductionmentioning

confidence: 99%

Ultra-fast bright field and fluorescence imaging of the dynamics of micrometer-sized objects

Chen

Wang

Versluis

et al. 2013

Review of Scientific Instruments

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High speed imaging has application in a wide area of industry and scientific research. In medical research, high speed imaging has the potential to reveal insight into mechanisms of action of various therapeutic interventions. Examples include ultrasound assisted thrombolysis, drug delivery, and gene therapy. Visual observation of the ultrasound, microbubble, and biological cell interaction may help the understanding of the dynamic behavior of microbubbles and may eventually lead to better design of such delivery systems. We present the development of a high speed bright field and fluorescence imaging system that incorporates external mechanical waves such as ultrasound. Through collaborative design and contract manufacturing, a high speed imaging system has been successfully developed at the University of Pittsburgh Medical Center. We named the system "UPMC Cam," to refer to the integrated imaging system that includes the multi-frame camera and its unique software control, the customized modular microscope, the customized laser delivery system, its auxiliary ultrasound generator, and the combined ultrasound and optical imaging chamber for in vitro and in vivo observations. This system is capable of imaging microscopic bright field and fluorescence movies at 25 × 10 6 frames per second for 128 frames, with a frame size of 920 × 616 pixels. Example images of microbubble under ultrasound are shown to demonstrate the potential application of the system.

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“…[3] There have been a number of recent studies demonstrating the potential of ultrasound as a means of promoting siRNA delivery both in vitro and in vivo. [4,5] Ultrasound mediated delivery can be significantly enhanced through the use of gas microbubbles that provide a means of encapsulating and improving tissue penetration and uptake of various therapeutics, including siRNA. For example, Carson et al used microbubbles for inhibition of endothelial growth factor (EGF) receptor signaling, an established strategy for treating numerous types of cancer.…”

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confidence: 99%

“…Their results indicated that tumor growth could be decelerated, arrested or even reversed in EGFR-treated mice. [4] Florinas et al similarly showed that microbubbles loaded with PEI (polyethylamine) encapsulating siRNA could induce knockdown of vascular EGF in vitro and decelerate tumor growth in vivo in a mouse model. [6] A further advantage of this approach is that the timescales for treatment are significantly reduced compared to passive delivery methods.…”

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confidence: 99%

Ultrasound‐Enhanced siRNA Delivery Using Magnetic Nanoparticle‐Loaded Chitosan‐Deoxycholic Acid Nanodroplets

Lee

Crake

Teo

et al. 2017

Adv Healthcare Materials

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Small interfering RNA (siRNA) has significant therapeutic potential but its clinical translation has been severely inhibited by a lack of effective delivery strategies. Previous work has demonstrated that perfluorocarbon nanodroplets loaded with magnetic nanoparticles can facilitate the intracellular delivery of a conventional chemotherapeutic drug. The aim of this study is to determine whether a similar agent can provide a means of delivering siRNA, enabling efficient transfection without degradation of the molecule. Chitosandeoxycholic acid nanoparticles containing perfluoropentane and iron oxide (d 0 = 7.5 ± 0.35 nm) with a mean hydrodynamic diameter of 257.6 ± 10.9 nm are produced. siRNA (AllStars Hs cell death siRNA) is electrostatically bound to the particle surface and delivery to lung cancer cells and breast cancer cells is investigated with and without ultrasound exposure (500 kHz, 1 MPa peakto-peak focal pressure, 40 cycles per burst, 1 kHz pulse repetition frequency, 10 s duration). The results show that siRNA functionality is not impaired by the treatment protocol and that the nanodroplets are able to successfully promote siRNA uptake, leading to significant apoptosis (52.4%) 72 h after ultrasound treatment.

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Ultrasound-Targeted Microbubble Destruction to Deliver siRNA Cancer Therapy

Cited by 145 publications

References 41 publications

Biophysical insight into mechanisms of sonoporation

Biophysical insight into mechanisms of sonoporation

Ultra-fast bright field and fluorescence imaging of the dynamics of micrometer-sized objects

Ultrasound‐Enhanced siRNA Delivery Using Magnetic Nanoparticle‐Loaded Chitosan‐Deoxycholic Acid Nanodroplets

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