Suicide gene therapy against cancer

El cáncer es una de las enfermedades con mayor mortalidad en todo el mundo, pero las terapias convencionales como la quimioterapia y la radioterapia no son eficaces en todos los casos y tienen amplios efectos secundarios. Para solventarlo se puede utilizar la terapia génica suicida, que consiste en inducir la muerte celular de las células cancerígenas mediante la introducción de un gen. Existen tres aproximaciones para el uso de esta terapia: la introducción de un gen codificante de un enzima generalmente bacteriano que activa un pro-fármaco, la introducción de un gen codificante de una toxina y la introducción de un gen pro-apoptótico. La expresión del gen se produce solamente en las células tumorales debido al uso de promotores tumor-específicos y vectores dirigidos. En estas tres aproximaciones se han desarrollado numerosos estudios con diversos sistemas llegando incluso a ensayos clínicos y productos aprobados para su uso en China (gendicina), viendo apoptosis de las células tumorales tanto in vitro como in vivo. Además, se han realizado mejoras en las técnicas mediante mutación de las enzimas y toxinas, modificación de los pro-fármacos y búsqueda de nuevas enzimas, toxinas o genes más activos, entre otros. A pesar de esto, se necesita seguir investigando en el campo para que la terapia sea totalmente dirigida y eficaz.Cancers are a large family of diseases with the highest mortality rate worldwide. Conventional therapies such as chemotherapy or radiotherapy are not efficient in all cases and have important side effects. To solve it, suicide gene therapy can be used. This therapy consists on inducing cell death of cancer cells due to the introduction of a gene. There are three types of this therapy: introduction of a gene encoding generally a bacterial enzyme that actives a prodrug, introduction of a gene encoding a toxin or introduction of a proapoptotic gene. The expression of the targeted gene in tumor cells is produced by using tumor-specific promoters and target vectors. Using those three gene suicide therapies many hallmarks in the field were reached, achieving successful clinical trials and products approved to be used in China (gendicine), achieving apoptosis of tumor cells in vitro and in vivo. Furthermore, several improvements on these techniques were developed due to the mutation of the enzymes and toxins, modification of prodrugs and search of new more active enzymes, toxins and genes, between others. Regardless, further research on this area is needed to guarantee the efficiency of this state-of-the-art therapy and its effectiveness

Generation of Calpain-3 knock-out porcine embryos by CRISPR-Cas9 electroporation and intracytoplasmic microinjection of oocytes before insemination

Limb girdle muscular dystrophy type R1 (LGMDR1) is an autosomal recessive myopathy described in humans resulting from a deficiency of calpain-3 protein (CAPN3). This disease lacks effective treatment and an appropriate model, so the generation of KO pigs by CRISPR-Cas9 offers a way to better understand disease ethology and to develop novel therapies. Microinjection is the main method described for gene editing by CRISPR-Cas9 in porcine embryo, but electroporation, which allows handling more embryos faster and easier, has also recently been reported. The objective of the current study was to optimize porcine oocyte electroporation to maximize embryo quality and mutation rate in order to efficiently generate LGMDR1 porcine models. We found that the efficiency of generating CAPN3 KO embryos was highest with 4 electroporation pulses and double sgRNA concentration than microinjection. Direct comparison between microinjection and electroporation demonstrated similar rates of embryo development and mutation parameters. The results of our study demonstrate that oocyte electroporation, an easier and faster method than microinjection, is comparable to standard approaches, paving the way for democratization of transgenesis in pigs

Production of Genetically Modified Porcine Embryos via Lipofection of Zona-Pellucida-Intact Oocytes Using the CRISPR/Cas9 System

Genetically modified pigs are very useful thanks to their applications in basic research, biomedicine, and meat production. There are different methods for producing them, including cloning and the microinjection or electroporation of oocytes and zygotes. Easier techniques are being developed, such as lipofection, which involves the encapsulation of the CRISPR/Cas9 system into vesicles that are introduced into cells. We compared the embryo development and mutation rates associated with different conditions of lipofection treatment with the electroporation technique in zona-pellucida-intact porcine oocytes. We found that the lipofection treatment, once optimized, was as effective as the electroporation technique in terms of the embryo development and mutation rates. In addition, an increment in the concentration in the media of the liposomes-CRISPR/Cas9 system complexes had a detrimental effect on the embryo development parameters, which could indicate a possible toxic effect. The achievement of generating mutant embryos via lipofection without removing the zona pellucida could open up a new, easy, and cheap way of producing genetically modified pigs.The generation of genetically modified pigs has an important impact thanks its applications in basic research, biomedicine, and meat production. Cloning was the first technique used for this production, although easier and cheaper methods were developed, such as the microinjection, electroporation, or lipofection of oocytes and zygotes. In this study, we analyzed the production of genetically modified embryos via lipofection of zona-pellucida-intact oocytes using Lipofectamine (TM) CRISPRMAX (TM) Cas9 in comparison with the electroporation method. Two factors were evaluated: (i) the increment in the concentration of the lipofectamine-ribonucleoprotein complexes (LRNPC) (5% vs. 10%) and (ii) the concentration of ribonucleoprotein within the complexes (1xRNP vs. 2xRNP). We found that the increment in the concentration of the LRNPC had a detrimental effect on embryo development and a subsequent effect on the number of mutant embryos. The 5% group had a similar mutant blastocyst rate to the electroporation method (5.52% and 6.38%, respectively, p > 0.05). The increment in the concentration of the ribonucleoprotein inside the complexes had no effect on the blastocyst rate and mutation rate, with the mutant blastocyst rate being similar in both the 1xRNP and 2xRNP lipofection groups and the electroporation group (1.75%, 3.60%, and 3.57%, respectively, p > 0.05). Here, we showed that it is possible to produce knock-out embryos via lipofection of zona-pellucida-intact porcine oocytes with similar efficiencies as with electroporation, although more optimization is needed, mainly in terms of the use of more efficient vesicles for encapsulation with different compositions

Production of Genetically Modified Porcine Embryos via Lipofection of Zona-Pellucida-Intact Oocytes Using the CRISPR/Cas9 System

The generation of genetically modified pigs has an important impact thanks its applications in basic research, biomedicine, and meat production. Cloning was the first technique used for this production, although easier and cheaper methods were developed, such as the microinjection, electroporation, or lipofection of oocytes and zygotes. In this study, we analyzed the production of genetically modified embryos via lipofection of zona-pellucida-intact oocytes using LipofectamineTM CRISPRMAXTM Cas9 in comparison with the electroporation method. Two factors were evaluated: (i) the increment in the concentration of the lipofectamine–ribonucleoprotein complexes (LRNPC) (5% vs. 10%) and (ii) the concentration of ribonucleoprotein within the complexes (1xRNP vs. 2xRNP). We found that the increment in the concentration of the LRNPC had a detrimental effect on embryo development and a subsequent effect on the number of mutant embryos. The 5% group had a similar mutant blastocyst rate to the electroporation method (5.52% and 6.38%, respectively, p > 0.05). The increment in the concentration of the ribonucleoprotein inside the complexes had no effect on the blastocyst rate and mutation rate, with the mutant blastocyst rate being similar in both the 1xRNP and 2xRNP lipofection groups and the electroporation group (1.75%, 3.60%, and 3.57%, respectively, p > 0.05). Here, we showed that it is possible to produce knock-out embryos via lipofection of zona-pellucida-intact porcine oocytes with similar efficiencies as with electroporation, although more optimization is needed, mainly in terms of the use of more efficient vesicles for encapsulation with different compositions

Production of genetically modified porcine embryos by lipofection of zona pellucida-intact oocytes using the CRISPR/Cas9 system

The generation of genetically modified pigs has an important impact thanks its applications in basic research, biomedicine, and meat production. Cloning was the first technique used for this production, although easier and cheaper methods were developed, such as the microinjection, electroporation, or lipofection of oocytes and zygotes. In this study, we analyzed the production of genetically modified embryos via lipofection of zona-pellucida-intact oocytes using LipofectamineTM CRISPRMAXTM Cas9 in comparison with the electroporation method. Two factors were evaluated: (i) the increment in the concentration of the lipofectamine–ribonucleoprotein complexes (LRNPC) (5% vs. 10%) and (ii) the concentration of ribonucleoprotein within the complexes (1xRNP vs. 2xRNP). We found that the increment in the concentration of the LRNPC had a detrimental effect on embryo development and a subsequent effect on the number of mutant embryos. The 5% group had a similar mutant blastocyst rate to the electroporation method (5.52% and 6.38%, respectively, p > 0.05). The increment in the concentration of the ribonucleoprotein inside the complexes had no effect on the blastocyst rate and mutation rate, with the mutant blastocyst rate being similar in both the 1xRNP and 2xRNP lipofection groups and the electroporation group (1.75%, 3.60%, and 3.57%, respectively, p > 0.05). Here, we showed that it is possible to produce knock-out embryos via lipofection of zona-pellucida-intact porcine oocytes with similar efficiencies as with electroporation, although more optimization is needed, mainly in terms of the use of more efficient vesicles for encapsulation with different compositions

Effect of aphidicolin, a reversible inhibitor of eukaryotic nuclear DNA replication, on the production of genetically modified porcine embryos by crispr/cas9.

©. This manuscript version is made available under the CC-BY 4.0 license http://creativecommons.org/licenses/by /4.0/ This document is the Published Manuscript version of a Published Work that appeared in final form in [International Journal of Molecular Sciences]. To access the final edited and published work see[https://doi.org/10.3390/ijms23042135

Oocyte electroporation prior to in vitro fertilization is an efficient method to generate single, double, and multiple knockout porcine embryos of interest in biomedicine and animal production

Genetically modified pigs play a critical role in mimicking human diseases, xenotransplantation, and the development of pigs resistant to viral diseases. The use of programmable endonucleases, including the CRISPR/Cas9 system, has revolutionized the generation of genetically modified pigs. This study evaluates the efficiency of electroporation of oocytes prior to fertilization in generating edited gene embryos for different models. For single gene editing, phospholipase C zeta (PLC ζ) and fused in sarcoma (FUS) genes were used, and the concentration of sgRNA and Cas9 complexes was optimized. The results showed that increasing the concentration resulted in higher mutation rates without affecting the blastocyst rate. Electroporation produced double knockouts for the TPC1/TPC2 genes with high efficiency (79 %). In addition, resistance to viral diseases such as PRRS and swine influenza was achieved by electroporation, allowing the generation of double knockout embryo pigs (63 %). The study also demonstrated the potential for multiple gene editing in a single step using electroporation, which is relevant for xenotransplantation. The technique resulted in the simultaneous mutation of 5 genes (GGTA1, B4GALNT2, pseudo B4GALNT2, CMAH and GHR). Overall, electroporation proved to be an efficient and versatile method to generate genetically modified embryonic pigs, offering significant advances in biomedical and agricultural research, xenotransplantation, and disease resistance. Electroporation led to the processing of numerous oocytes in a single session using less expensive equipment. We confirmed the generation of gene-edited porcine embryos for single, double, or quintuple genes simultaneously without altering embryo development to the blastocyst stage. The results provide valuable insights into the optimization of gene editing protocols for different models, opening new avenues for research and applications in this field.This research was funded by Fundación Séneca 22065/PI/22, Instituto de Salud Carlos III Proyectos de Desarrollo Tecnológico AES 2019 (DTS19/00061), Spanish Ministry of Science, Innovation and Universities: MICIN PID2020-113366RB-I00, MCIN/AEI/10.13039/501100011033/, FEDER Una manera de hacer Europa; Universidad de Murcia predoctoral fellowship R-496/2022

Generation of Calpain-3 knock-out porcine embryos by CRISPR-Cas9 electroporation and intracytoplasmic microinjection of oocytes before insemination.

©. This manuscript version is made available under the CC-BY4.0 license http://creativecommons.org/licenses/by /4.0/ This document is the Published version of a Published Work that appeared in final form in [Theriogenology]. To access the final edited and published work see[https://doi.org10.1016/j.theriogenology.2022.04.012