Targeting bcr-abl transcripts with siRNAs in an imatinib-resistant chronic myeloid leukemia patient: challenges and future directions

ETV6 gene aberrations in non-haematological malignancies: A review highlighting ETV6 associated fusion genes in solid tumors

ETV6 (translocation-Ets-leukemia virus) gene is a transcriptional repressor mainly involved in haematopoiesis and maintenance of vascular networks and has developed to be a major oncogene with the potential ability of forming fusion partners with many other genes with carcinogenic consequences. ETV6 fusions function primarily by constitutive activation of kinase activity of the fusion partners, modifications in the normal functions of ETV6 transcription factor, loss of function of ETV6 or the partner gene and activation of a proto-oncogene near the site of translocation. The role of ETV6 fusion gene in tumorigenesis has been well-documented and more variedly found in haematological malignancies. However, the role of the ETV6 oncogene in solid tumors has also risen to prominence due to an increasing number of cases being reported with this malignancy. Since, solid tumors can be well-targeted, the diagnosis of this genre of tumors based on ETV6 malignancy is of crucial importance for treatment. This review highlights the important ETV6 associated fusions in solid tumors along with critical insights as to existing and novel means of targeting it. A consolidation of novel therapies such as immune, gene, RNAi, stem cell therapy and protein degradation hitherto unused in the case of ETV6 solid tumor malignancies may open further therapeutic avenues.

Lipid nanoparticle-mediated siRNA delivery for safe targeting of human CML in vivo

Efficient and safe delivery of siRNA in vivo is the biggest roadblock to clinical translation of RNA interference (RNAi)-based therapeutics. To date, lipid nanoparticles (LNPs) have shown efficient delivery of siRNA to the liver; however, delivery to other organs, especially hematopoietic tissues still remains a challenge. We developed DLin-MC3-DMA lipid-based LNP-siRNA formulations for systemic delivery against a driver oncogene to target human chronic myeloid leukemia (CML) cells in vivo. A microfluidic mixing technology was used to obtain reproducible ionizable cationic LNPs loaded with siRNA molecules targeting the BCR-ABL fusion oncogene found in CML. We show a highly efficient and non-toxic delivery of siRNA in vitro and in vivo with nearly 100% uptake of LNP-siRNA formulations in bone marrow of a leukemic model. By targeting the BCR-ABL fusion oncogene, we show a reduction of leukemic burden in our myeloid leukemia mouse model and demonstrate reduced disease burden in mice treated with LNP-BCR-ABL siRNA as compared with LNP-CTRL siRNA. Our study provides proof-of-principle that fusion oncogene specific RNAi therapeutics can be exploited against leukemic cells and promise novel treatment options for leukemia patients.

Lipoplexes from Non-viral Cationic Vectors: DOTAP-DOPE Liposomes and Gemini Micelles

This chapter describes the topic of gene therapy based on colloidal drug delivery, as an alternative to the use of viral carriers. Non-viral vectors are promising transfection agents and do not suffer from limitations related to toxicity and immunogenic effects. In particular, lipid-based aggregates are generally considered biocompatible and versatile nanocarriers whose composition can be designed to include a cationic molecule which ensures strong interaction with nucleic acid. Herein the main issues related to complex formation and in vitro administration are illustrated with key examples, such as liposome-DNA plasmid (pDNA) association and micelles-siRNA complexes.

RNAi-mediated Control of Aflatoxins in Peanut: Method to Analyze Mycotoxin Production and Transgene Expression in the Peanut/Aspergillus Pathosystem

The Food and Agriculture Organization of the United Nations estimates that 25% of the food crops in the world are contaminated with aflatoxins. That represents 100 million tons of food being destroyed or diverted to non-human consumption each year. Aflatoxins are powerful carcinogens normally accumulated by the fungi Aspergillus flavus and A. parasiticus in cereals, nuts, root crops and other agricultural products. Silencing of five aflatoxin-synthesis genes by RNA interference (RNAi) in peanut plants was used to control aflatoxin accumulation following inoculation with A. flavus. Previously, no method existed to analyze the effectiveness of RNAi in individual peanut transgenic events, as these usually produce few seeds, and traditional methods of large field experiments under aflatoxin-conducive conditions were not an option. In the field, the probability of finding naturally contaminated seeds is often 1/100 to 1/1,000. In addition, aflatoxin contamination is not uniformly distributed. Our method uses few seeds per transgenic event, with small pieces processed for real-time PCR (RT-PCR) or small RNA sequencing, and for analysis of aflatoxin accumulation by ultra-performance liquid chromatography (UPLC). RNAi-expressing peanut lines 288-72 and 288-74, showed up to 100% reduction (p ≤ 0.01) in aflatoxin B1 and B2 compared to the control that accumulated up to 14,000 ng · g(-1) of aflatoxin B1 when inoculated with aflatoxigenic A. flavus. As reference, the maximum total of aflatoxins allowable for human consumption in the United States is 20 ng · g(-1). This protocol describes the application of RNAi-mediated control of aflatoxins in transgenic peanut seeds and methods for its evaluation. We believe that its application in breeding of peanut and other crops will bring rapid advancement in this important area of science, medicine and human nutrition, and will significantly contribute to the international effort to control aflatoxins, and potentially other mycotoxins in major food crops.