Stearoyl CoA Desaturase-1 Silencing in Glioblastoma Cells: Phospholipid Remodeling and Cytotoxicity Enhanced upon Autophagy Inhibition

Modulation of lipid metabolism is a well-established cancer hallmark, and SCD1 has been recognized as a key enzyme in promoting cancer cell growth, including in glioblastoma (GBM), the deadliest brain tumor and a paradigm of cancer resistance. The central goal of this work was to identify, by MS, the phospholipidome alterations resulting from the silencing of SCD1 in human GBM cells, in order to implement an innovative therapy to fight GBM cell resistance. With this purpose, RNAi technology was employed, and low serum-containing medium was used to mimic nutrient deficiency conditions, at which SCD1 is overexpressed. Besides the expected increase in the saturated to unsaturated fatty acid ratio in SCD1 silenced-GBM cells, a striking increase in polyunsaturated chains, particularly in phosphatidylethanolamine and cardiolipin species, was noticed and tentatively correlated with an increase in autophagy (evidenced by the increase in LC3BII/I ratio). The contribution of autophagy to mitigate the impact of SCD1 silencing on GBM cell viability and growth, whose modest inhibition could be correlated with the maintenance of energetically associated mitochondria, was evidenced by using autophagy inhibitors. In conclusion, SCD1 silencing could constitute an important tool to halt GBM resistance to the available treatments, especially when coupled with a mitochondria disrupter chemotherapeutic.

Progress on ocular siRNA gene-silencing therapy and drug delivery systems

Age-related macular degeneration (AMD) and glaucoma are global ocular diseases with high blindness rate. RNA interference (RNAi) is being increasingly used in the treatment of these disorders with siRNA drugs, bevasiranib, AGN211745 and PF-04523655 for AMD, and SYL040012 and QPI-1007 for glaucoma. Administration routes and vectors of gene drugs affect their therapeutic effect. Compared with the non-viral vectors, viral vectors have limited payload capacity and potential immunogenicity. This review summarizes the progress of the ocular siRNA gene-silencing therapy by focusing on siRNA drugs for AMD and glaucoma already used in clinical research, the main routes of drug delivery and the non-viral vectors for siRNA drugs.

Current and innovative emerging therapies for porphyrias with hepatic involvement

Porphyrias are rare inherited disorders caused by specific enzyme dysfunctions in the haem synthesis pathway, which result in abnormal accumulation of specific pathway intermediates. The symptoms depend upon the chemical characteristics of these substances. Porphyrins are photoreactive and cause photocutaneous lesions on sunlight-exposed areas, whereas accumulation of porphyrin precursors is related to acute neurovisceral attacks. Current therapies are suboptimal and mostly address symptoms rather than underlying disease mechanisms. Advances in the understanding of the molecular bases and pathogenesis of porphyrias have paved the way for the development of new therapeutic strategies. In this Clinical Trial Watch we summarise the basic principles of these emerging approaches and what is currently known about their application to porphyrias of hepatic origin or with hepatic involvement.

RNA interference technology used for the study of aquatic virus infections

Aquaculture is one of the most important economic activities in Asia and is presently the fastest growing sector of food production in the world. Explosive increases in global fish farming have been accompanied by an increase in viral diseases. Viral infections are responsible for huge economic losses in fish farming, and control of these viral diseases in aquaculture remains a serious challenge. Recent advances in biotechnology have had a significant impact on disease reduction in aquaculture. RNAi is one of the most important technological breakthroughs in modern biology, allowing us to directly observe the effects of the loss of specific genes in living systems. RNA interference technology has emerged as a powerful tool for manipulating gene expression in the laboratory. This technology represents a new therapeutic approach for treating aquatic diseases, including viral infections. RNAi technology is based on a naturally occurring post-transcriptional gene silencing process mediated by the formation of dsRNA. RNAi has been proven widely effective for gene knockdown in mammalian cultured cells, but its utility in fish remains unexplored. This review aims to highlight the RNAi technology that has made significant contributions toward the improvement of aquatic animal health and will also summarize the current status and future strategies concerning the therapeutic applications of RNAi to combat viral disease in aquacultured organisms.