Image-guided Gene Therapy Research Articles

Near-Infrared II Fluorescence Imaging and Image-Guided siRNA Therapy of Atherosclerosis.

Targeting Ca2+/calmodulin-dependent protein kinase γ (CaMKIIγ) in macrophages using RNAi nanotechnology represents an innovative and promising strategy in the diagnosis and treatment of atherosclerosis. Nevertheless, it remains elusive because of the current challenges associated with the systemic delivery of siRNA nanoparticle (NP) to atheromatous plaques and the complexity of atherosclerotic plaques. Here, we demonstrate the potential of a thienothiadiazole-based near-infrared-II (NIR-II) organic aggregation-induced emission (AIE) platform encapsulated with the Camk2g siRNA to effectively target CaMKIIγ in macrophages for dynamic imaging and image-guided gene therapy of atherosclerosis. The nanoparticles effectively decreased CaMKIIγ expression and increased the expression of the efferocytosis receptor MerTK in plaque macrophages, leading to a reduction in the necrotic core area of the lesion in an aortic plaque model. Our theranostic approach highlights the substantial promise of near-infrared II (NIR-II) AIEgens for imaging and image-guided therapy of atherosclerosis.

Lanthanide-based β-Tricalcium Phosphate Upconversion Nanoparticles as an Effective Theranostic Nonviral Vectors for Image-Guided Gene Therapy.

Lanthanide-based beta-tricalcium phosphate (β-TCP) upconversion nanoparticles are exploited as a non-viral vector for imaging guided-gene therapy by virtue of their unique optical properties and multi-modality imaging ability, high transfection efficiency, high biocompatibility, dispersibility, simplicity of synthesis and surface modification. Ytterbium and thulium-doped β-TCP nanoparticles (βTCPYbTm) are synthesized via co-precipitation method, coated with polyethylenimine (PEI) and functionalized with a nuclear-targeting peptide (TAT). Further, in vitro studies revealed that the nanotheranostic carriers are able to transfect cells with the plasmid eGFP at a high efficiency, with approximately 60% of total cells producing the fluorescent green protein. The optimized protocol developed comprises the most efficient βTCPYbTm/PEI configuration, the amount and the order of assembly of βTCPYbTm:PEI, TAT, plasmid DNA and the culturing conditions. With having excellent dispersibility and high chemical affinity toward nucleic acid, calcium ions released from βTCPYbTm:PEI nanoparticles can participate in delivering nucleic acids and other therapeutic molecules, overcoming the nuclear barriers and improving the transfection efficacy. Equally important, the feasibility of the upconversion multifunctional nanovector to serve as an effective contrast agent for imaging modality, capable of converting low-energy light to higher-energy photons via a multi-photons mechanism, endowing greater unique luminescent properties, was successfully demonstrated.

Development of Theranostic Cationic Liposomes Designed for Image-Guided Delivery of Nucleic Acid.

Cationic liposomes have been considered as potential vectors for gene delivery thanks to their ability to transfect cells with high efficiency. Recently, the combination of diagnostic agent and therapeutic agents in the same particle to form a theranostic system has been reported. Magnetic liposomes are one of these examples. Due to the magnetic nanoparticles encapsulated in the liposomes, they can act as a drug delivery system and, at the same time, a magnetic resonance imaging contrast enhancement agent or hyperthermia. In this work, nucleic acid delivery systems based on magnetic cationic liposomes (MCLs) were developed. Two different techniques, reverse phase evaporation and cosolvent sonication, were employed for liposome preparation. Both strategies produced MCLs of less than 200 nm with highly positive charge. Enhancement of their transverse and longitudinal relaxivities r2 and r1 was obtained with both kinds of magnetic liposomes compared to free magnetic nanoparticles. Moreover, these MCLs showed high capacity to form complexes and transfect CT-26 cells using the antibiotic-free pFAR4-luc plasmid. The transfection enhancement with magnetofection was also carried out in CT26 cells. These results suggested that our MCLs could be a promising candidate for image-guided gene therapy.

PH-Responsive Degradable Dextran-Quantum Dot Nanohybrids for Enhanced Gene Delivery.

It is of great significance to develop biocompatible and degradable gene carriers with stimuli-enhanced gene therapy and imaging function. In this work, low-cytotoxic polycation PGEA (ethanolamine-functionalized poly(glycidyl methacrylate))-functionalized dextran-quantum dot (QD) nanohybrids (DQ-PGEA) were proposed as safe and efficient gene carriers via a facile and feasible method. The highly water-soluble dextran gives the carrier good stability, biocompatibility, and abundant modification sites, while QDs allow fluorescence (FL) imaging. Taking advantage of the pH-responsive self-destruction characteristic introduced by Schiff base linkages, DQ-PGEA nanohybrids could not only result in enhanced gene release but also contribute to the elimination of the carriers. Reduced (nondegradable) DQ-PGEA-R nanohybrids were also synthesized as counterparts to reveal the superiority of the responsive DQ-PGEA carriers. The effectiveness of the as-prepared gene delivery systems was verified adopting the antioncogene p53 in the mouse model of breast cancer. As expected, DQ-PGEA nanohybrids demonstrated a superior gene transfection performance and antitumor inhibition compared with their counterparts. Meanwhile, the gene delivery processes could be tracked in real time to visualize the therapeutic processes and realize FL imaging-guided gene therapy. The current multifunctional stimuli-responsive nanoplatforms with the self-destruction feature are intriguing candidates to achieve enhanced gene therapy for tumor treatment.

A 89Zr-labeled lipoplex nanosystem for image-guided gene delivery: design, evaluation of stability and in vivo behavior.

BackgroundWith the advances in radiopharmaceutical research, the development of image-guided therapy has become a major interest. While the development of theranostic nanotherapeutics is frequently associated with cancer chemotherapy, phototherapy and radiotherapy, there is little information available on the in vivo monitoring of gene delivery systems and the application of image-guided approach in gene therapy. The goal of this work was to determine the in vivo behavior of DNA delivery nanosystems - based on cationic gemini surfactants – designed for image-guided gene therapy. We tested the feasibility of monitoring tumor accumulation of gene delivery nanoparticles by positron emission tomography.MethodsTo be able to conjugate radiotracers to the nanoparticles, a deferoxamine-modified gemini surfactant was synthesized, DNA-containing lipoplex nanoparticles were formulated, and radiolabeled with Zirconium-89 (89Zr). The pharmacokinetics and biodistribution of 89Zr labeled surfactant and 89Zr labeled nanoparticles were monitored in mice by microPET/CT imaging and ex vivo gamma counting.ResultsModification of the nanoparticles with deferoxamine did not alter their physicochemical properties. The radiolabeled nanoparticles (labeling efficiency of 95±3%) were stable in PBS and serum. The biological half-life of the 89Zr labeled nanoparticles was significantly higher compared to 89Zr labeled surfactant. As expected, the nanoparticles had significantly higher liver accumulation than the radiolabeled surfactant alone and lower kidney accumulation. Tumor uptake was detected at 2 hours post injection and decreased throughout the 3-day monitoring.ConclusionWe propose that radiolabeling DNA delivery lipoplex nanosystems is a promising approach for the design and optimization of image-guided nanomedicines, especially in the context of cancer gene therapy.

Engineering Persistent Luminescence Nanoparticles for Biological Applications: From Biosensing/Bioimaging to Theranostics.

Persistent luminescence nanoparticles (PLNPs) are unique optical materials emitting long-lasting luminescence after ceasing excitation. Such a unique optical feature allows luminescence detection without constant external illumination to avoid the interferences of autofluorescence and scattering light from biological fluids and tissues. Besides, near-infrared (NIR) PLNPs have advantages of deep penetration and the reactivation of the persistent luminescence (PL) by red or NIR light. These features make the application of NIR-emitting PLNPs in long-term bioimaging no longer limited by the lifetime of PL. To take full advantage of PLNPs for biological applications, the versatile strategies for bridging PLNPs and biological system become increasingly significant for the design of PLNPs-based nanoprobes. In this Account, we summarize our systematic achievements in the biological applications of PLNPs from biosensing/bioimaging to theranostics with emphasizing the engineering strategies for fabricating specific PLNPs-based nanoprobes. We take surface engineering and manipulating energy transfer as the major principles to design various PLNPs-based nanoprobes based on the nature of interactions between nanoprobes and targets. We have developed target-induced formation or interruption of fluorescence resonance energy transfer systems for autofluorescence-free biosensing and imaging of cancer biomarkers. We have decorated single or dual targeting ligands on PLNPs for tumor-targeted imaging, and integrated other modal imaging agents into PLNPs for multimodal imaging. We have also employed specific functionalization for various biomedical applications including chemotherapy, photodynamic therapy, photothermal therapy, stem cells tracking and PL imaging-guided gene therapy. Besides, we have modified PLNPs with multiple functional units to achieve challenging metastatic tumor theranostics. The proposed design principle and comprehensive strategies show great potential in guiding the design of PLNPs nanoprobes and promoting further development of PLNPs in the fields of biological science and medicine. We conclude this Account by outlining the future directions to further promote the practical application of PLNPs. The novel protocols for the synthesis of small-size, monodisperse, and water-soluble PLNPs with high NIR PL intensity and superlong afterglow are the vibrant directions for the biomedical applications of PLNPs. In-depth theories and evidence on luminescence mechanism of PLNPs are highly desired for further improvement of their luminescence performance. Furthermore, other irradiations without tissue penetrating depth limit, such as X-ray, are encouraged for use in energy storage and re-excitation of PLNPs, enabling imaging in deep tissue in vivo and integrating other X-ray sensitized theranostic techniques such as computed tomography imaging and radiotherapy. Last but not least, PLNPs-based nanoprobes and the brand new hybrids of PLNPs with other nanomaterials show a bright prospect for accurate diagnosis and efficient treatment of diseases besides tumors.

SPION loaded poly(L-lysine)/hyaluronic acid micelles as MR contrast agent and gene delivery vehicle for cancer theranostics

In this work we evaluated the ability of a SPION (Superparamagnetic iron oxide nanoparticle) loaded micelle system to safely and efficiently transfer foreign DNA into cells with the help of poly(L-lysine) (PLL) as DNA-carrier. Average particle size of PLL coated hyaluronic acid (HA) loaded SPION (PLL-HA-SPION) micelle was approximately 200 nm in size with spherical morphology. PLL-HA-SPION micelle was found to be nontoxic to the NIH3T3 (murine fibroblast cells) and the in vitro uptake was also tested in CT-26 (murine colon cancer cells) by prussian blue staining. Agarose gel retardation study showed the efficient binding of PLL-HA-SPION micelle with plasmid DNA (pLuc). The formed PLL-HA-SPION/pLuc complex could be efficiently transfected into CT-26 cell line. Finally, MR imaging was also used to check uptake property of SPION loaded in PLL-HA-SPION/DNA complex in vitro. The result showed that the PLL-HA-SPION micelle can be applied to MR imagingguided gene therapy in vivo and it is also advantageous for using this system for the magnetic hyperthermia based cancer therapy.

Asymmetrically functionalized β-cyclodextrin-based star copolymers for integrated gene delivery and magnetic resonance imaging contrast enhancement

We report on the synthesis of star copolymers possessing dual functions of gene delivery vectors and magnetic resonance (MR) imaging contrast enhancement. Starting from asymmetrically functionalized β-cyclodextrin (β-CD) comprising 7 azide moieties and 14 α-bromopropionate functionalities at the upper and lower rim of a rigid toroidal β-CD core, (DOTA-Gd)7-CD-(PDMA)14 star copolymers were synthesized via atom transfer radical polymerization (ATRP) of N,N-dimethylaminoethyl methacrylate (DMA) and subsequent click reaction with an alkynyl-functionalized gadolinium (Gd3+) complex, DOTA-Gd, where DOTA is 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid. The obtained Janus-type star copolymers, (DOTA-Gd)7-CD-(PDMA)14, could completely complex with anionic plasmid DNA (pDNA) via electrostatic interactions at N/P ratios equal to or higher than 2 and exhibit optimal in vitro transfection efficiency at an N/P ratio of 8. In addition, in vitro MR imaging experiments demonstrated considerably enhanced T1 relaxivity (r1 ∼ 10.9 s−1 mM−1) for the star copolymer compared to that of commercially available small molecular MR imaging contrast agents (2.4–3.2 s−1 mM−1). The star-type topology of asymmetrically functionalized β-CD based copolymers in combination with the integrated design of diagnostic and therapeutic functions augurs well for their potential applications in the field of image-guided gene therapy.

Synthesis and characterization of magnetic nanoparticle-embedded multi-functional polymeric micelles for MRI-guided gene delivery

Superparamagnetic iron oxide nanoparticle (SPION)-based diagnostic properties with accompanying therapeutics such as drugs or genes have been explored for improvement of their therapeutic efficacy. Positively charged SPION-loaded polymersomes was prepared to deliver genes to the target sites; this process was concomitantly monitored by magnetic resonance imaging (MRI). The surface characteristics and morphology were respectively measured by dynamic light scattering and transmission electron microscopy. The complex between the polymer and the pDNA was confirmed by a gel retardation assay. The transfection efficiency and cytotoxicity in vitro were tested by treating of the CT-26 colon cancer cell line with luciferase-expressing plasmids/SPION complex. MRI was also used to check the detectability of SPION in vitro and in vivo. A SPION-loaded polymersome carrying genetic materials was delivered and then accumulated in the tumor site of the murine colon cancer xenograft model after intravenous injection, possibly through a passive targeting mechanism. The accumulation was monitored using clinical MRI. This result indicates that the SPION-loaded polymersome can be applied to MR imageguided gene therapy. Open image in new window

Superparamagnetic Iron Oxide Nanoparticles-Loaded Polymersome-Mediated Gene Delivery Guided by Enhanced Magnetic Resonance Signal

Positively charged superparamagnetic iron oxide nanoparticle (SPION)-loaded polymersome was prepared in order to deliver genes to the target sites, which was monitored by magnetic resonance imaging (MRI), concomitantly. The transfection efficiency in vitro was tested by treating CT-26 colon cancer cell line with luciferase-expressing plasmids/SPION complex. MRI was also used to check the detectability of SPION in vitro and in vivo. SPION-loaded polymersome, carrying genetic materials, was delivered and then accumulated at the tumor site of the murine colon cancer xenograft model after intravenous injection, possibly through a passive targeting mechanism. Clinical MRI monitored this accumulation. This result indicates that the SPION-loaded polymersomecan be applied to MR image-guided gene therapy.

Eradication of Therapy-resistant Human Prostate Tumors Using an Ultrasound-guided Site-specific Cancer Terminator Virus Delivery Approach

Intratumoral injections of a replication-incompetent adenovirus (Ad) expressing melanoma differentiation-associated gene-7/interleukin-24 (Ad.mda-7), a secreted cytokine displaying cancer-selective, apoptosis-inducing properties, profoundly inhibits prostate cancer (PC) growth in immune-incompetent animals. In contrast, Ad.mda-7 is ineffective in PCs overexpressing antiapoptotic proteins such as Bcl-2 or Bcl-x(L). However, intratumoral injections of a conditionally replication-competent Ad (CRCA) in which expression of the adenoviral E1A gene is driven by the cancer-specific promoter of progression-elevated gene-3 (PEG-3) and which simultaneously expresses mda-7/interleukin (IL)-24 in the E3 region of the Ad (Ad.PEG-E1A-mda-7), a cancer terminator virus (CTV), is highly active in these cells. A major challenge for gene therapy is systemic delivery of nucleic acids directly into an affected tissue. Ultrasound (US) contrast agents (microbubbles-MBs) are viable candidates for gene delivery/therapy. Here, we show that MB/Ad.mda-7 complexes targeted to DU-145 cells using US dramatically reduced tumor burden in xenografted nude mice. Additionally, US-guided MB/CTV delivery completely eradicated not only targeted DU-145/Bcl-x(L)-therapy-resistant tumors, but also nontargeted distant tumors (established in the opposite flank), thereby implementing a cure. These findings highlight potential therapeutic applications of this novel image-guided gene therapy technology for advanced PC patients with metastatic disease.

Imaging-Guided Gene Therapy of Experimental Gliomas

To further develop gene therapy for patients with glioblastomas, an experimental gene therapy protocol was established comprising a series of imaging parameters for (i) noninvasive assessment of viable target tissue followed by (ii) targeted application of herpes simplex virus type 1 (HSV-1) amplicon vectors and (iii) quantification of treatment effects by imaging. We show that viable target tissue amenable for application of gene therapy vectors can be identified by multitracer positron emission tomography (PET) using 2-(18)F-fluoro-2-deoxy-D-glucose, methyl-(11)C-L-methionine, or 3'-deoxy-3'-(18)F-fluoro-L-thymidine ([(18)F]FLT). Targeted application of HSV-1 amplicon vectors containing two therapeutic genes with synergistic antitumor activity (Escherichia coli cytosine deaminase, cd, and mutated HSV-1 thymidine kinase, tk39, fused to green fluorescent protein gene, gfp) leads to an overall response rate of 68%, with 18% complete responses and 50% partial responses. Most importantly, we show that the "tissue dose" of HSV-1 amplicon vector-mediated gene expression can be noninvasively assessed by 9-[4-(18)F-fluoro-3-(hydroxymethyl)butyl]guanine ([(18)F]FHBG) PET. Therapeutic effects could be monitored by PET with significant differences in [(18)F]FLT accumulation in all positive control tumors and 72% in vivo transduced tumors (P = 0.01) as early as 4 days after prodrug therapy. For all stably and in vivo transduced tumors, cdIREStk39gfp gene expression as measured by [(18)F]FHBG-PET correlated with therapeutic efficiency as measured by [(18)F]FLT-PET. These data indicate that imaging-guided vector application with determination of tissue dose of vector-mediated gene expression and correlation to induced therapeutic effect using multimodal imaging is feasible. This strategy will help in the development of safe and efficient gene therapy protocols for clinical application.

Imaging-guided gene therapy of gliomas

Imaging-guided gene therapy of gliomas

Molecular imaging-guided gene therapy of experimental gliomas

Background: The combination of transgenes encoding prodrug-activating enzymes serves synergistic anti-tumor activity (e.g. E. coli cytosine deaminase (cd) and HSV-1 thymidine kinase (tk)). We used positron emission tomography (PET) and magnetic resonance imaging (MRI) for imaging-guided targeted application of universal HSV-1 amplicon vectors and assessment of therapeutic efficiency.