Minicircle DNA: The Future for DNA-Based Vectors?

Almeida, Ana Margarida; Queiroz, João A.; Sousa, Fani; Sousa, Ângela

doi:10.1016/j.tibtech.2020.04.008

Cited by 30 publications

(24 citation statements)

References 15 publications

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“…However, there are some reports that gene silencing of CMV promoter-driven transgenes has been demonstrated to be associated with DNA methylation [ 35 , 36 , 37 , 38 ]. This transcriptional silencing of CMV promoter could occur after a certain period from 7 days to 49 days post-transduction, which varied between different cell types [ 22 , 39 , 40 ]. Therefore, to further develop our gene replacement therapy for RDEB treatment, employment of a human promoter sequence to control COL7A1 expression may help to minimize the risk of immunogenic and/or oncogenic events, and avoid any other unexpected effects from a CMV promoter.…”

Section: Discussionmentioning

confidence: 99%

“…Furthermore, keratinocytes are more accessible than the deep dermal fibroblasts, which makes them easier to treat and to be obtained from patients. In fact, they are the target in most skin topical treatments studies [ 40 ]. However, as we mention above, there is still an urgent demand for developing a DNA delivery vector that has large payload capacity and highly efficient transfection of both dermal keratinocytes and epidermal fibroblasts.…”

Section: Discussionmentioning

confidence: 99%

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Development of Minicircle Vectors Encoding COL7A1 Gene with Human Promoters for Non-Viral Gene Therapy for Recessive Dystrophic Epidermolysis Bullosa

Wang

Alshehri

Manzanares

et al. 2021

IJMS

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Recessive dystrophic epidermolysis bullosa (RDEB) is a rare autosomal inherited skin disorder caused by mutations in the COL7A1 gene that encodes type VII collagen (C7). The development of an efficient gene replacement strategy for RDEB is mainly hindered by the lack of vectors able to encapsulate and transfect the large cDNA size of this gene. To address this problem, our group has opted to use polymeric-based non-viral delivery systems and minicircle DNA. With this approach, safety is improved by avoiding the usage of viruses, the absence of bacterial backbone, and the replacement of the control viral cytomegalovirus (CMV) promoter of the gene with human promoters. All the promoters showed impressive C7 expression in RDEB skin cells, with eukaryotic translation elongation factor 1 α (EF1α) promoter producing higher C7 expression levels than CMV following minicircle induction, and COL7A1 tissue-specific promoter (C7P) generating C7 levels similar to normal human epidermal keratinocytes. The improved system developed here has a high potential for use as a non-viral topical treatment to restore C7 in RDEB patients efficiently and safely, and to be adapted to other genetic conditions.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Development of Minicircle Vectors Encoding COL7A1 Gene with Human Promoters for Non-Viral Gene Therapy for Recessive Dystrophic Epidermolysis Bullosa

Wang

Alshehri

Manzanares

et al. 2021

IJMS

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“…The protein was introduced as a transgene within a minicircle. Minicircles are plasmids that are void of the bacterial backbone, leading to a smaller size with less immunogenicity and higher rate of transfection [4,5]. They have been studied mostly in the field of gene therapy.…”

Section: Introductionmentioning

confidence: 99%

Cancer Detection Using an Artificial Secretable MicroRNA Found in Blood and Urine

et al. 2022

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Biomarkers can potentially help in the detection and prognosis of diseases such as cancer, its recurrence, predicting response to therapy, and monitoring of response during and/or after treatment. Endogenous tumor blood biomarkers suffer from low concentrations that are not distinguishable from background noise and, if identified, the localization of the biomarker production site is not known. The use of exogenously introduced or artificial biomarkers can eliminate these issues. In this study, we show that cancer cells can be made to produce an artificial secreted microRNA (Sec-miR) that can be detected in media from cells in culture, and from both blood and urine in living mice. In culture, we show that chaining a number of Sec-miR sequences in a plasmid and transfecting cells with the plasmids could increase Sec-miR secretion as the number of sequences increases. Tumor induction in mice with a stably transfected HeLa cell line shows the presence and significant increase in the Sec-miR with time and tumor growth in plasma (p < 0.001, R2 = 0.5542). The relative half-life of the Sec-miR was seen to be 1.2 h in the plasma of living mice and was seen to appear in urine within 12 h. The transgene for the Sec-miR within a minicircle was introduced via the tail-vein into subcutaneous tumor-bearing mice. As the tumor growth increased with time, further in vivo transfection of the Sec-miR minicircles showed an increase in Sec-miR in both plasma and urine (R2 = 0.4546). This study demonstrated that an exogenous Sec-miR biomarker would allow for early tumor detection using in vitro diagnostics techniques.

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“…Among the different DNA vaccines, minicircle DNA (mcDNA) is an innovative and promising DNA molecule. The absence of prokaryotic sequences on the mcDNA overcome some key limitations of the traditional plasmid DNA [ 5 ]. E6 and E7 viral oncoproteins are suitable targets for the formulation of therapeutic vaccines, since they are overexpressed in HPV-infected cells at early stages [ 1 ].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Characterization of Mannosylated Formulations to Deliver a Minicircle DNA Vaccine

Serra

Eusébio²,

Neves³

et al. 2021

Pharmaceutics

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DNA vaccines still represent an emergent area of research, giving rise to continuous progress towards several biomedicine demands. The formulation of delivery systems to specifically target mannose receptors, which are overexpressed on antigen presenting cells (APCs), is considered a suitable strategy to improve the DNA vaccine immunogenicity. The present study developed binary and ternary carriers, based on polyethylenimine (PEI), octa-arginine peptide (R8), and mannose ligands, to specifically deliver a minicircle DNA (mcDNA) vaccine to APCs. Systems were prepared at various nitrogen to phosphate group (N/P) ratios and characterized in terms of their morphology, size, surface charge, and complexation capacity. In vitro studies were conducted to assess the biocompatibility, cell internalization ability, and gene expression of formulated carriers. The high charge density and condensing capacity of both PEI and R8 enhance the interaction with the mcDNA, leading to the formation of smaller particles. The addition of PEI polymer to the R8-mannose/mcDNA binary system reduces the size and increases the zeta potential and system stability. Confocal microscopy studies confirmed intracellular localization of targeting systems, resulting in sustained mcDNA uptake. Furthermore, the efficiency of in vitro transfection can be influenced by the presence of R8-mannose, with great implications for gene expression. R8-mannose/PEI/mcDNA ternary systems can be considered valuable tools to instigate further research, aiming for advances in the DNA vaccine field.

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Minicircle DNA: The Future for DNA-Based Vectors?

Cited by 30 publications

References 15 publications

Development of Minicircle Vectors Encoding COL7A1 Gene with Human Promoters for Non-Viral Gene Therapy for Recessive Dystrophic Epidermolysis Bullosa

Development of Minicircle Vectors Encoding COL7A1 Gene with Human Promoters for Non-Viral Gene Therapy for Recessive Dystrophic Epidermolysis Bullosa

Cancer Detection Using an Artificial Secretable MicroRNA Found in Blood and Urine

Synthesis and Characterization of Mannosylated Formulations to Deliver a Minicircle DNA Vaccine

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