The establishment of CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9) technology for eukaryotic gene editing opened up new avenues not only for the analysis of gene function but also for therapeutic interventions. While the original methodology allowed for targeted gene disruption, recent technological advancements yielded a rich assortment of tools to modify genes and gene expression in various ways. Currently, clinical applications of this technology fell short of expectations mainly due to problems with the efficient and safe delivery of CRISPR/Cas9 components to living organisms. The targeted in vivo delivery of therapeutic nucleic acids and proteins remain technically challenging and further limitations emerge, for instance, by unwanted off-target effects, immune reactions, toxicity, or rapid degradation of the transfer vehicles. One approach that might overcome many of these limitations employs extracellular vesicles as intercellular delivery devices. In this review, we first introduce the CRISPR/Cas9 system and its latest advancements, outline major applications, and summarize the current state of the art technology using exosomes or microvesicles for transporting CRISPR/Cas9 constituents into eukaryotic cells.

: Nanomedicine is a good alternative to traditional methods of cancer treatment, but does not solve all the limitations of oncology. Nanoparticles used in anticancer therapy can work as carriers of drugs, nucleic acids, imaging agents or they can sensitize cells to radiation. The present review focuses on the application of nanoparticles to treating cancer, as well as on its problems and limitations. Using nanoparticles as drug carriers, significant improvement in the efficiency of transport of compounds and their targeting directly to the tumour has been achieved; it also reduces the side effects of chemotherapeutic drugs on the body. However, nanoparticles do not significantly improve the effectiveness of the chemotherapeutic agent itself. Most nanodrugs can reduce toxicity of chemotherapy, but do not significantly affect the effectiveness of treatment. Nanodrugs should be developed that can be effective as an anti-metastatic treatment, e.g. by enhancing the ability of nanoparticles to transport chemotherapeutic loads to sentinel lymph nodes using the immune system, and developing chemotherapy in specific metastatic areas. Gene therapy, however, is the most modern method of treating cancer, the cause of cancer being tackled by altering genetic material. Other applications of nanoparticles for radiotherapy and diagnostics are discussed.

Gene therapy is a promising approach in cancer treatment; however, current methods have a number of limitations mainly due to the difficulty in delivering therapeutic nucleic acids to their sites of action. The application of non-viral carriers based on nanomaterials aims at protecting genetic material from degradation and enabling its effective intracellular transport. We proposed the use of silver nanoparticles (AgNPs) surface-modified with carbosilane dendrons as carriers of anticancer siRNA (siBcl-xl). Using gel electrophoresis, zeta potential and hydrodynamic diameter measurements, as well as transmission electron microscopy, we characterized AgNP:siRNA complexes and demonstrated the stability of nucleic acid in complexes in the presence of RNase. Hemolytic properties of free silver nanoparticles and complexes, their effect on lymphocyte proliferation and cytotoxic activity on HeLa cells were also examined. Confocal microscopy proved the effective cellular uptake of complexes, indicating the possible use of this type of silver nanoparticles as carriers of genetic material in gene therapy.

The fact that cancer is one of the leading causes of death requires researchers to create new systems of effective treatment for malignant tumors. One promising area is genetic therapy that uses small interfering RNA (siRNA). These molecules are capable of blocking mutant proteins in cells, but require specific systems that will deliver RNA to target cells and successfully release them into the cytoplasm. Dendronized and PEGylated silver nanoparticles as potential vectors for proapoptotic siRNA (siMCL-1) were used here. Using the methods of one-dimensional gel electrophoresis, the zeta potential, dynamic light scattering, and circular dichroism, stable siRNA and AgNP complexes were obtained. Data gathered using multicolor flow cytometry showed that AgNPs are able to deliver (up to 90%) siRNAs efficiently to some types of tumor cells, depending on the degree of PEGylation. Analysis of cell death showed that complexes of some AgNP variations with siMCL-1 lead to ~70% cell death in the populations that uptake these complexes due to apoptosis.