Viral Vectors, Engineered Cells and the CRISPR Revolution.

Over the past few decades the ability to edit human cells has revolutionized modern biology and medicine. With advances in genome editing methodologies, gene delivery and cell-based therapeutics targeted at treatment of genetic disease have become a reality that will become more and more essential in clinical practice. Modifying specific mutations in eukaryotic cells using CRISPR-Cas systems derived from prokaryotic immune systems has allowed for precision in correcting various disease mutations. Furthermore, delivery of genetic payloads by employing viral tropism has become a crucial and effective mechanism for delivering genes and gene editing systems into cells. Lastly, cells modified ex vivo have tremendous potential and have shown effective in studying and treating a myriad of diseases. This chapter seeks to highlight and review important progress in the realm of the editing of human cells using CRISPR-Cas systems, the use of viruses as vectors for gene therapy, and the application of engineered cells to study and treat disease.

Bcl-2 inhibitor and apigenin worked synergistically in human malignant neuroblastoma cell lines and increased apoptosis with activation of extrinsic and intrinsic pathways.

Neuroblastoma is the most common extracranial solid tumor in infants and young children. Current treatments are not always effective and new therapies are needed. We examined efficacy of combination of the small molecule Bcl-2 inhibitor HA14-1 (HA) and the dietary isoflavonoid apigenin (APG) in human malignant neuroblastoma cells. Dose-response studies indicated that treatment with HA and APG for 24 h synergistically reduced cell viability in human malignant neuroblastoma SK-N-DZ, SH-SY5Y, and IMR32 cells. For further studies, we selected SK-N-DZ cells that showed the highest sensitivity following treatment with 2.5 microM HA, 100 microM APG, or combination (2.5 microM HA+100 microM APG). Wright staining showed increase in morphological features of apoptosis. Cell cycle distribution and Annexin V assay showed that combination therapy caused more apoptosis than either treatment alone. Western blotting revealed that combination therapy downregulated angiogenic factors and also induced extrinsic pathway of apoptosis with activation of caspase-8 for Bid cleavage to tBid. Alterations in Bax and Bcl-2 levels resulted in an increase in Bax:Bcl-2 ratio to activate intrinsic pathway of apoptosis with mitochondrial release of cytochrome c into the cytosol and activation of proteases. Increases in calpain and caspase-3 activities generated 145 kD spectrin break down product (SBDP) and 120 kD SBDP, respectively. Results showed that combination of HA and APG could be used for downregulation of angiogenic factors and activation of extrinsic and intrinsic pathways of apoptosis in malignant neuroblastoma cells.