Exosome-Liposome Hybrid Nanoparticles Deliver CRISPR/Cas9 System in MSCs

Linkage between endosomal escape of LNP-mRNA and loading into EVs for transport to other cells

RNA-based therapeutics hold great promise for treating diseases and lipid nanoparticles (LNPs) represent the most advanced platform for RNA delivery. However, the fate of the LNP-mRNA after endosome-engulfing and escape from the autophagy-lysosomal pathway remains unclear. To investigate this, mRNA (encoding human erythropoietin) was delivered to cells using LNPs, which shows, for the first time, a link between LNP-mRNA endocytosis and its packaging into extracellular vesicles (endo-EVs: secreted after the endocytosis of LNP-mRNA). Endosomal escape of LNP-mRNA is dependent on the molar ratio between ionizable lipids and mRNA nucleotides. Our results show that fractions of ionizable lipids and mRNA (1:1 molar ratio of hEPO mRNA nucleotides:ionizable lipids) of endocytosed LNPs were detected in endo-EVs. Importantly, these EVs can protect the exogenous mRNA during in vivo delivery to produce human protein in mice, detected in plasma and organs. Compared to LNPs, endo-EVs cause lower expression of inflammatory cytokines.

Exosomes as Carriers for Antitumor Therapy

Exosomes are bilayer vesicles with particle sizes between 50 and 150 nm. Owing to their bilayer membrane structure, cell-to-cell communication, and good absorbability, exosomes are increasingly used as carriers for drug delivery through phospholipid membrane structures to lesion sites with enhanced targeting. Exosome sources and drug-loading methods are important factors affecting their use as drug carriers. There are various ways to pack species in exosomes, and researchers are constantly seeking new and improved approaches. In both in vivo and in vitro evaluations, exosomal vectors have achieved good antitumor efficacies. Despite the importance of exosomes as drug delivery systems with accurate targeting ability and biocompatibility, improvements are needed to facilitate their widespread clinical use. This review focuses on the preparation of exosomes as carriers and their utilization in antitumor research.

The Role of Exosomes in Pancreatic Cancer

Pancreatic cancer remains one of the deadliest cancers in the world, as a consequence of late diagnosis, early metastasis and limited response to chemotherapy, under which conditions the potential mechanism of pancreatic cancer progression requires further study. Exosomes are membrane vesicles which are important in the progression, metastasis and chemoresistance in pancreatic cancer. Additionally, they have been verified to be potential as biomarkers, targets and drug carriers for pancreatic cancer treatment. Thus, studying the role of exosomes in pancreatic cancer is significant. This paper focuses on the role of exosomes in the proliferation, metastasis and chemoresistance, as well as their potential applications for pancreatic cancer.

Disruption of splicing-regulatory elements using CRISPR/Cas9 to rescue spinal muscular atrophy in human iPSCs and mice

We here report a genome-editing strategy to correct spinal muscular atrophy (SMA). Rather than directly targeting the pathogenic exonic mutations, our strategy employed Cas9 and guide-sgRNA for the targeted disruption of intronic splicing-regulatory elements. We disrupted intronic splicing silencers (ISSs, including ISS-N1 and ISS + 100) of survival motor neuron (SMN) 2, a key modifier gene of SMA, to enhance exon 7 inclusion and full-length SMN expression in SMA iPSCs. Survival of splicing-corrected iPSC-derived motor neurons was rescued with SMN restoration. Furthermore, co-injection of Cas9 mRNA from Streptococcus pyogenes (SpCas9) or Cas9 from Staphylococcus aureus (SaCas9) alongside their corresponding sgRNAs targeting ISS-N1 into zygotes rescued 56% and 100% of severe SMA transgenic mice (Smn^−/−, SMN2^tg/−). The median survival of the resulting mice was extended to >400 days. Collectively, our study provides proof-of-principle for a new strategy to therapeutically intervene in SMA and other RNA-splicing-related diseases.

Friend or Foe? Evidence Indicates Endogenous Exosomes Can Deliver Functional gRNA and Cas9 Protein

The clustered regularly interspaced short palindromic repeats (CRISPR)/associated nuclease (Cas) system is an efficient gene editing tool. In this study, it is found that both single guide RNA (gRNA) and Cas9 protein could be exported from the CRISPR/Cas9-expressing cells by endogenous exosomes independently. Further experiments demonstrate that these naturally produced endogenous exosomes could be used as a vehicle to deliver the functional Cas9 and hepatitis B virus (HBV)-specific gRNA to cut HBV DNA transfected in HuH7 cells or human papilloma virus (HPV)-specific gRNA to cut the integrated HPV DNA in HeLa cells, respectively. In conclusion, this study indicates the potential of endogenous exosomes as a safe and effective delivery vehicle of the functional gRNA and Cas9 protein. Meanwhile, the endogenous exosomes-mediated delivery of gene editing activity to adjacent and distant cells or tissues may further complicate the off-target and safety concerns about the CRISPR/Cas9 system.

Macrophage-derived exosome-mimetic hybrid vesicles for tumor targeted drug delivery

Extracellular vesicles (EVs) are phospholipid and protein constructs which are continuously secreted by cells in the form of smaller (30-200 nm) and larger (micron size) particles. While all of these vesicles are called as EVs, the smaller size are normally called as exosomes. Small EVs (sEVs) have now been explored as a potential candidate in therapeutics delivery owing to their endogenous functionality, intrinsic targeting property, and ability to cooperate with a host defense mechanism. Considering these potentials, we hypothesize that immune cell-derived sEVs can mimic immune cell to target cancer. However, different sEVs isolation technique reported poor yield and loss of functional properties. To solve this problem, herein we hybridized sEVs with synthetic liposome to engineer vesicles with size less than 200 nm to mimic the size of exosome and named as hybrid exosome (HE). To achieve this goal, sEVs from mouse macrophage was hybridized with synthetic liposome to engineer HE. The fluorescence-based experiment confirmed the successful hybridization process yielding HE with the size of 177 ± 21 nm. Major protein analysis from Blot techniques reveal the presence of EV marker proteins CD81, CD63, and CD9. Differential cellular interaction of HE was observed when treated with normal and cancerous cells thereby supporting our hypothesis. Moreover, a water-soluble doxorubicin was loaded in HE. Drug-loaded HE showed enhanced toxicity against cancer cells and pH-sensitive drug release in acidic condition, benefiting drug delivery to acidic cancer environment. These results suggest that the engineered HE would be an exciting platform for tumor-targeted drug delivery. STATEMENT OF SIGNIFICANCE: Extracellular vesicles (EVs) are phospholipid and protein constructs which are continuously secreted by cells in the human body. These vesicles can efficiently deliver their parental biomolecules to the recipient cells and assist in intracellular communication without a direct cell-to-cell contact. Moreover, they have the ability to perform some of the molecular task similar to that of its parent cells. For example, exosome derived from immune cells can seek for diseased and/or inflammatory cells by reading the cell surface proteins. However, different EVs isolation techniques reported poor yield and loss of functional properties. Therefore, to overcome this limitation, we herein propose to re-engineer immuno-exosome with a synthetic liposome as a refined biomimetic nanostructure for the delivery of doxorubicin (clinical drug) for breast cancer treatment.

Biomaterials as vectors for the delivery of CRISPR-Cas9

The emergence of the CRISPR-Cas9 gene editing system has brought much hope and excitement to the field of gene therapy and the larger scientific community. However, in order for CRISPR-based therapies to be translated to the clinical setting, there is an urgent need to develop optimized vectors for their delivery. The delivery vector is a crucial determinant of the therapeutic efficacy of gene editing and should be designed to accommodate various factors including the form of the payload, the physiological environment, and the potential immune responses. Recently, biomaterials have become an attractive option for the delivery of Cas9 due to their tunability, biocompatibility and increasing efficacy at drug delivery. Biomaterials offer a unique solution for creating tailored vectors to meet the demands of various applications that cannot be easily met by other delivery methods. In this review, we will discuss the various biomaterial systems that have been used to deliver Cas9 in its plasmid, mRNA and protein forms. In addition, the functions of these materials will be reviewed to understand their roles in Cas9 delivery. Finally, the immune challenges associated with Cas9 and the delivery materials will be discussed as an understanding of the immune responses along with the functions of biomaterials will ultimately guide the field in designing new delivery systems for the clinical applications of CRISPR-Cas9.

Calcium chloride enhances the delivery of exosomes

Exosomes might have an unimproved potential to serve as effective delivery vehicles. However, when exosomes are developed for therapeutic applications, a method to enhance their delivery is important. This study aimed to evaluate wheather calcium chloride (CaCl₂) or other chloride compounds could enhance exosome delivery to various cells without causing toxicity. Exosomes were purified from human serum by using the ExoQuick exosome precipitation kit. Isolated exosomes were mixed with CaCl₂ at concentrations ranging from 100 μM to 1 mM, and then washed using Amicon filter for treating the cells. The delivery efficiency of exosomes and the viability of the cells [HEK 293 (human kidney cells) and H9C2 (rat cardiomyocytes)] were evaluated. Cellular uptake of exosomes was observed using a confocal microscope based on PKH26 labeling of exosomes. CaCl₂ increased the delivery of exosomes in a dose- and treatment time-dependent manner. In HEK 293 cells, a CaCl₂ concentration of 400 μM and exposure time of 12 h increased the delivery of exosomes by >20 times compared with controls. In H9C2 cells, a CaCl₂ concentration of 400 μM and exposure time of >24 h increased the delivery of exosomes by >400 times compared with controls. The viability of both cell lines was maintained up to a CaCl₂ concentration of 1 mM. However, cobalt chloride, cupric chloride, and magnesium chloride did not change the delivery of exosomes in both cell lines. These results suggest that the use of CaCl₂ treatment might be a useful method for enhancing the delivery of exosomes.

Interplay of Darwinian Selection, Lamarckian Induction and Microvesicle Transfer on Drug Resistance in Cancer

Development of drug resistance in cancer has major implications for patients’ outcome. It is related to processes involved in the decrease of drug efficacy, which are strongly influenced by intratumor heterogeneity and changes in the microenvironment. Heterogeneity arises, to a large extent, from genetic mutations analogously to Darwinian evolution, when selection of tumor cells results from the adaptation to the microenvironment, but could also emerge as a consequence of epigenetic mutations driven by stochastic events. An important exogenous source of alterations is the action of chemotherapeutic agents, which not only affects the signalling pathways but also the interactions among cells. In this work we provide experimental evidence from in vitro assays and put forward a mathematical kinetic transport model to describe the dynamics displayed by a system of non-small-cell lung carcinoma cells (NCI-H460) which, depending on the effect of a chemotherapeutic agent (doxorubicin), exhibits a complex interplay between Darwinian selection, Lamarckian induction and the nonlocal transfer of extracellular microvesicles. The role played by all of these processes to multidrug resistance in cancer is elucidated and quantified.

CRISPR/Cas9 Delivery Mediated with Hydroxyl-Rich Nanosystems for Gene Editing in Aorta

A CRISPR/Cas9 system has emerged as a powerful tool for gene editing to treat genetic mutation related diseases. Due to the complete endothelial barrier, effective delivery of the CRISPR/Cas9 system to vasculatures remains a challenge for in vivo gene editing of genetic vascular diseases especially in aorta. Herein, it is reported that CHO-PGEA (cholesterol (CHO)-terminated ethanolamine-aminated poly(glycidyl methacrylate)) with rich hydroxyl groups can deliver a plasmid based pCas9-sgFbn1 system for the knockout of exon 10 in Fbn1 gene. This is the first report of a polycation-mediated CRISPR/Cas9 system for gene editing in aorta of adult mice. CHO-PGEA/pCas9-sgFbn1 nanosystems can effectively contribute to the knockout of exon 10 in Fbn1 in vascular smooth muscle cells in vitro, which leads to the change of the phosphorylation of Smad2/3 and the increased expression of two downstream signals of Fbn1: Mmp-2 and Ctgf. For in vivo application, the aortic enrichment of CHO-PGEA/Cas9-sgFbn1 is achieved by administering a pressor dose of angiotensin II (Ang II). The effects of the pCas9-sgFbn1 system targeting Fbn1 demonstrate an increase in the expression of Mmp-2 and Ctgf in aorta. Thus, the combination of CHO-PGEA/pCas9-sgFbn1 nanosystems with Ang II infusion can provide the possibility for in vivo gene editing in aorta.

Mesenchymal Stem Cell (MSC)-Derived Extracellular Vesicles: Potential Therapeutics as MSC Trophic Mediators in Regenerative Medicine

Mesenchymal stem cells (MSCs) are pluripotent progenitor cells with the capabilities of self-renewing, differentiating into multiple lineages, and achieving trophic effects during tissue repair. MSCs can secrete extracellular vesicles (EVs) including exosomes and microvesicles, which mediate their trophic effects on other cells. Carrying a variety of intracellular molecules of MSCs including lipids, proteins, RNA (mRNA and noncoding RNA), and DNA, EVs deliver them into other cells to regulate tissue regeneration process. The therapeutic effects of MSC-derived EVs have been observed in a number of animal disease models. In this review, we focus on the current state and future directions of MSC-derived EVs in regenerative medicine. Anat Rec, 2019. © 2019 Wiley Periodicals, Inc.

A CRISPR/Cas9 based polymeric nanoparticles to treat/inhibit microbial infections

The latest breakthrough towards the adequate and decisive methods of gene editing tools provided by CRISPR/Cas9 (Clustered Regularly Interspaced Short Palindromic Repeat/CRISPR Associated System), has been repurposed into a tool for genetically engineering eukaryotic cells and now considered as the major innovation in gene-related disorders. Nanotechnology has provided an alternate way to overcome the conventional problems where methods to deliver therapeutic agents have failed. The use of nanotechnology has the potential to safe-side the CRISPR/Cas9 components delivery by using customized polymeric nanoparticles for safety and efficacy. The pairing of two (CRISPR/Cas9 and nanotechnology) has the potential for opening new avenues in therapeutic use. In this review, we will discuss the most recent advances in developing nanoparticle-based CRISPR/Cas9 gene editing cargo delivery with a focus on several polymeric nanoparticles including fabrication proposals to combat microbial infections.

Extracellular Vesicles: Delivery Vehicles of Myokines

Movement and regular physical activity are two important factors that help the human body prevent, reduce and treat different chronic diseases such as obesity, type 2 diabetes, heart diseases, hypertension, sarcopenia, cachexia and cancer. During exercise, several tissues release molecules into the blood stream, and are able to mediate beneficial effects throughout the whole body. In particular, contracting skeletal muscle cells have the capacity to communicate with other organs through the release of humoral factors that play an important role in the mechanisms of adaptation to physical exercise. These muscle-derived factors, today recognized as myokines, act as endocrine and paracrine hormones. Moreover, exercise may stimulate the release of small membranous vesicles into circulation, whose composition is influenced by the same exercise. Combining the two hypotheses, these molecules related to exercise, named exer-kines, might be secreted from muscle cells inside small vesicles (nanovesicles). These could act as messengers in tissue cross talk during physical exercise. Thanks to their ability to deliver useful molecules (such as proteins and miRNA) in both physiological and pathological conditions, extracellular vesicles can be thought of as promising candidates for potential therapeutic and diagnostic applications for several diseases.

Near-infrared upconversion-activated CRISPR-Cas9 system: A remote-controlled gene editing platform

As an RNA-guided nuclease, CRISPR-Cas9 offers facile and promising solutions to mediate genome modification with respect to versatility and high precision. However, spatiotemporal manipulation of CRISPR-Cas9 delivery remains a daunting challenge for robust effectuation of gene editing both in vitro and in vivo. Here, we designed a near-infrared (NIR) light-responsive nanocarrier of CRISPR-Cas9 for cancer therapeutics based on upconversion nanoparticles (UCNPs). The UCNPs served as "nanotransducers" that can convert NIR light (980 nm) into local ultraviolet light for the cleavage of photosensitive molecules, thereby resulting in on-demand release of CRISPR-Cas9. In addition, by preparing a single guide RNA targeting a tumor gene (polo-like kinase-1), our strategies have successfully inhibited the proliferation of tumor cell via NIR light-activated gene editing both in vitro and in vivo. Overall, this exogenously controlled method presents enormous potential for targeted gene editing in deep tissues and treatment of a myriad of diseases.

Harnessing Exosomes for the Development of Brain Drug Delivery Systems

Brain drug delivery is one of the most important bottlenecks in the development of drugs for the central nervous system. Cumulative evidence has emerged that extracellular vesicles (EVs) play a key role in intercellular communication. Exosomes, a subgroup of EVs, have received the most attention due to their capability in mediating the horizontal transfer of their bioactive inclusions to neighboring and distant cells, and thus specifically regulating the physiological and pathological functions of the recipient cells. This native and unique signaling mechanism confers exosomes with great potential to be developed into an effective, precise, and safe drug delivery system. Here, we provide an overview into the challenges of brain drug delivery and the function of exosomes in the brain under physiological and pathological conditions, and discuss how these natural vesicles could be harnessed for brain drug delivery and for the therapy of brain diseases.

Embryonic Stem Cells-Derived Exosomes Endowed with Targeting Properties as Chemotherapeutics Delivery Vehicles for Glioblastoma Therapy

Exosomes are nanosized membrane vesicles (30-100 nm) that can easily penetrate the blood-brain barrier, safely deliver therapeutic drugs, and be modified with target ligands. Embryonic stem cells (ESCs) provide abundant exosome sources for clinical application due to their almost unlimited self-renewal. Previous studies show that exosomes secreted by ESCs (ESC-exos) have antitumor properties. However, it is not known whether ESC-exos inhibit glioblastoma (GBM) growth. In this study, the anti-GBM effect of ESC-exos is confirmed and then c(RGDyK)-modified and paclitaxel (PTX)-loaded ESC-exos, named cRGD-Exo-PTX are prepared. It is then investigated whether the engineered exosomes deliver more efficiently to GBM cells versus free drug alone and drug-loaded ESC-exos using an in vitro GBM model and in vivo subcutaneous and orthotopic xenografts model. The results show that cRGD-Exo-PTX significantly improves the curative effects of PTX in GBM via enhanced targeting. These data indicate that ESC-exos are potentially powerful therapeutic carriers for GBM and could have utility in many other diseases.

Exploiting Exosomes in Cancer Liquid Biopsies and Drug Delivery

Exosomes are cell-derived nanovesicles that transfer molecular cargo from donor to recipient cells and mediate intercellular communication. Advancement in elucidating the biological capabilities and functionalities of exosomes has revealed the striking roles of exosomes as conveyors of bioactive molecules across the biological barriers. Tumor-derived exosomes hold great promise to serve as a liquid biopsy tool for cancer diagnosis and prognosis, as large quantities of exosomes are excreted by tumor cells continuously into the circulation, carrying the molecular cargo (DNA, RNA, proteins) reflective of the genetic and signaling alterations in tumor cells. Two inherent characteristics of exosomes offer important opportunities for drug delivery: their superb transcellular permeability and biocompatibility. Exosomes are uniquely capable of encapsulating a variety of payloads and deliver them to the target tissues. This review discusses the potential of tumor-derived exosomes in cancer liquid biopsies as well as the underlying mechanisms. Furthermore, the recent progress of developing exosomes as highly versatile and efficient drug carriers is also summarized.

Non-Viral Delivery To Enable Genome Editing

Genome-editing technologies such as zinc-finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENS), and the clustered regularly interspaced short palindromic repeat (CRISPR)-associated protein system have revolutionized biological research. Each biotechnology consists of a DNA-binding protein that can be programmed to recognize and initiate double-strand breaks (DSBs) for site-specific gene modification. These technologies have the potential to be harnessed to cure diseases caused by aberrant gene expression. To be successful therapeutically, their functionality depends on their safe and efficient delivery into the cell nucleus. This review discusses the challenges in the delivery of genome-editing tools, and highlights recent innovations in non-viral delivery that have potential to overcome these limitations and advance the translation of genome editing towards patient care.

Suppressing the NHEJ pathway by DNA-PKcs inhibitor NU7026 prevents degradation of HBV cccDNA cleaved by CRISPR/Cas9

Chronic hepatitis B is a severe liver disease caused by hepatitis B virus (HBV) infection. Covalently closed circular DNA (cccDNA), a super-spiralized, double-stranded form of the HBV genome, is the major determinant of viral persistence. CRISPR/Cas9 nucleases have been recently shown to introduce double-stranded DNA breaks into HBV cccDNA. The inflicted damage results predominantly in erroneous repair of cccDNA by non-homologous end-joining (NHEJ). NHEJ has been suggested to enhance anti-HBV activity of CRISPR/Cas9 and increase cccDNA mutation. In this study, we assessed anti-HBV activity of CRISPR/Cas9 and cccDNA repair outcomes in an altered NHEJ/HR environment. NU7026, a strong inhibitor of NHEJ, prevented CRISPR/Cas9-mediated degradation of cccDNA and resulted in frequent on-target deletions. We conclude that CRISPR/Cas9 is a highly effective tool to degrade cccDNA and first demonstrate that inhibiting NHEJ impairs cccDNA degradation.

Design strategies and application progress of therapeutic exosomes

Exosomes have great potential to be drug delivery vehicles due to their natural material transportation properties, intrinsic long-term circulatory capability, and excellent biocompatibility, which are suitable for delivering a variety of chemicals, proteins, nucleic acids, and gene therapeutic agents. However, an effective method of loading specific protein agents into exosomes for absorption by target cells is still lacking. The application potential of exosome is still limited. In this review, we discussed the methods for loading specific treating molecules (proteins, nucleic acids and small chemicals) into exosomes, the design strategies for cell and tissue targeting, and the factors for exosome formation. This review can be used as a reference for further research as well as for the development of therapeutic exosomes.

In Vitro and in Vivo RNA Inhibition by CD9-HuR Functionalized Exosomes Encapsulated with miRNA or CRISPR/dCas9

In vitro and in vivo delivery of RNAs of interest holds promise for gene therapy. Recently, exosomes are considered as a kind of rational vehicle for RNA delivery, especially miRNA and/or siRNA, while the loading efficiency is limited. In this study, we engineered the exosomes for RNA loading by constructing a fusion protein in which the exosomal membrane protein CD9 was fused with RNA binding protein, while the RNA of interest either natively harbors or is engineered to have the elements for the binding. By proof-of-principle experiments, we here fused CD9 with HuR, an RNA binding protein interacting with miR-155 with a relatively high affinity. In the exosome packaging cells, the fused CD9-HuR successfully enriched miR-155 into exosomes when miR-155 was excessively expressed. Moreover, miR-155 encapsulated in the exosomes in turn could be efficiently delivered into the recipient cells and recognized the endogenous targets. In addition, we also revealed that the CD9-HuR exosomes could enrich the functional miRNA inhibitor or CRISPR/dCas9 when the RNAs were engineered to have the AU rich elements. Taken together, we here have established a novel strategy for enhanced RNA cargo encapsulation into engineered exosomes, which in turn functions in the recipient cells.

Exosome Biochemistry and Advanced Nanotechnology for Next-Generation Theranostic Platforms

Recent marked technological advances in the field of exosome nanotechnology have provided unprecedented opportunities to bloom the developments of exosome-related biology, chemistry, pathology, and therapeutics, which have laid a solid basis for scientific community to design exosome-based nanotheranostic platforms. The unique structural/compositional/morphological characteristics of exosomes as natural nanocarriers, as well as their fascinating physicochemical/biochemical properties, which underpin their special physiopathological roles, have triggered the concept that these cell-derived nanovesicles with intrinsic biological functions can be highly competent for the establishment of next-generation nanomedicine. Herein, efforts are made to give a comprehensive overview on the recent advances of exosome nanotechnology based on the representative examples of the current state of the art of exosome-based research, ranging from their formation, biological function, preparation, and characterization to their extensive nanomedical applications. It is highly expected that the better and clearer elucidation of the fundamental principles for advanced nanotechnology in constructing exosome-based theranostic nanoplatforms, as well as integrating the intrinsic advantages of exosomes as endogenous cell-derived nanocarriers with the advanced design methodology of traditional nanomedicine, will help to unlock the innate powers of exosomes for the establishment of next-generation theranostic nanoplatforms.

Latest advances in extracellular vesicles: from bench to bedside

Extracellular vesicles (EVs) are small membraned vesicles and approximately 50-150 nm in diameter. Almost all of the type of cells releases the EVs and circulates in the body fluids. EVs contain multiple functional components, such as mRNAs, microRNAs (miRNAs), DNAs, and proteins, which can be transferred to the recipient cells, resulting in phenotypic changes. Recently, EV research has focused on their potential as a drug delivery vehicle and in targeted therapy against specific molecules. Moreover, some surface proteins are specific to particular diseases, and therefore, EVs also have promise as biomarkers. In this concise review, we summarize the latest research focused on EVs, which have the potential to become a promising drug delivery method, biomarker, and new therapeutic target for improving the outcomes of cancer patients.

Delivery of an Artificial Transcription Regulator dCas9-VPR by Extracellular Vesicles for Therapeutic Gene Activation

The CRISPR/Cas system has been developed as a potent tool for genome engineering and transcription regulation. However, the efficiency of the delivery of the system into cells, particularly for therapeutic in vivo applications, remains a major bottleneck. Extracellular vesicles (EVs), released by eukaryotic cells, can mediate the transfer of various molecules, including nucleic acids and proteins. We show the packaging and delivery of the CRISPR/Cas system via EVs to the target cells, combining the advantages of both technological platforms. A genome editing with designed extracellular vesicles (GEDEX) system generated by the producer cells can transfer the designed transcriptional regulator dCas9-VPR complexed with appropriate targeting gRNAs enabling activation of gene transcription. We show functional delivery in mammalian cells as well in the animals. The therapeutic efficiency of in vivo delivery of dCas9-VPR/sgRNA GEDEX is demonstrated in a mouse model of liver damage counteracted by upregulation of the endogenous hepatocyte growth factor, demonstrating the potential for therapeutic applications.

Delivery systems of CRISPR/Cas9-based cancer gene therapy

CRISPR/Cas9 (Clustered Regularly Interspaced Short Palindromic Repeats) is today one of the most reliable method for gene-editing, supporting previous gene therapies technologies such as TALEN, Meganucleases and ZFNs. There is a growing up number of manuscripts reporting several successful gene-edited cancer cell lines, but the real challenge is to translate this technique to the clinical practice. While treatments for diseases based on a single gene mutation is closer, being possible to target and repair the mutant allele in a selective way generating specific guide RNAs (gRNAs), many steps need to be done to apply CRISPR to face cancer. In this review, we want to give a general overview to the recent advancements in the delivery systems of the CRISPR/Cas9 machinery in cancer therapy.

Delivery of CRISPR/Cas9 by Novel Strategies for Gene Therapy

Precise editing of the genome of a living body is a goal pursued by scientists in many fields. In recent years, CRISPR (clustered regularly interspaced short palindromic repeat)/Cas (CRISPR-associated) genome-editing systems have become a revolutionary toolbox for gene editing across various species. However, the low transfection efficiency of the CRISPR/Cas9 system to mammalian cells in vitro and in vivo is a big obstacle hindering wide and deep application. In this review, recently developed delivery strategies for various CRISPR/Cas9 formulations and their applications in treating gene-related diseases are briefly summarized. This review should inspire others to explore more efficient strategies for CRISPR system delivery and gene therapy.

A Promising Biocompatible Platform: Lipid-Based and Bio-Inspired Smart Drug Delivery Systems for Cancer Therapy

Designing new drug delivery systems (DDSs) for safer cancer therapy during pre-clinical and clinical applications still constitutes a considerable challenge, despite advances made in related fields. Lipid-based drug delivery systems (LBDDSs) have emerged as biocompatible candidates that overcome many biological obstacles. In particular, a combination of the merits of lipid carriers and functional polymers has maximized drug delivery efficiency. Functionalization of LBDDSs enables the accumulation of anti-cancer drugs at target destinations, which means they are more effective at controlled drug release in tumor microenvironments (TMEs). This review highlights the various types of ligands used to achieve tumor-specific delivery and discusses the strategies used to achieve the effective release of drugs in TMEs and not into healthy tissues. Moreover, innovative recent designs of LBDDSs are also described. These smart systems offer great potential for more advanced cancer therapies that address the challenges posed in this research area.

Exosomes at a glance - common nominators for cancer hallmarks and novel diagnosis tools

Cancer represents a heterogeneous disease with multiple levels of regulation and a dynamic environment that sustains the evolution of the malignant mass. This dynamic is in part sustained by a class of extracellular vesicles termed exosomes that are able to imprint the pathological state by incorporating differential cargos in order to facilitate cell-to-cell communication. Exosomes are stable within the extracellular medium and function as shuttles secreted by healthy or pathological cells, being further taken by the accepting cell with direct effects on its phenotype. The exosomal trafficking is deeply involved in multiple levels of cancer development with roles in all cancer hallmarks. Nowadays, studies are constantly exploring the ability of exosomes to sustain the malignant progression in order to attack this pathological trafficking and impair the ability of the tumor mass to expand within the organisms. As important, the circulatory characteristics of exosomes represent a steady advantage regarding the possibility of using them as minimally invasive diagnosis tools, where cancer patients' present modified exosomal profiles compared to the healthy ones. This last characteristic, as novel diagnosis tools, has the advantage of a possible rapid transition within the clinic, compared to the studies that evaluate the therapeutic meaning.