RNAi therapeutics are promising therapeutic tools that have sparked the interest of many researchers. In an effort to provide a safe alternative to PEI, we have designed a series of new guanidinium- and morpholino-functionalized biocompatible and biodegradable polycarbonate vectors. The impact of different functions (morpholino-, guanidinium-, hydrophobic groups) of the architecture (linear homopolymer to dumbbell-shape) and of the molecular weight of these copolymers on their capacity to form polyplexes and to decrease the expression of two epigenetic regulators of gene expression, HDAC7 and HDAC5, was evaluated. The use of one of these polymers combining morpholine and guanidine functions at the ratio >1 and hydrophobic trimethylene carbonate groups showed a significant decrease of mRNA and protein level in HeLa cells, similar to PEI. These results highlight the potential of polycarbonate vectors for future in vivo application as an anticancer therapy.

Guanidine and morpholine functionalized aliphatic polycarbonate polymers able to efficiently deliver histone deacetylase 5 (HDAC5) siRNA into the cytoplasm of cancer cells in vitro leading to a decrease of cell proliferation were previously developed. To allow these biodegradable and biocompatible polyplex nanoparticles to overcome the extracellular barriers and be effective in vivo after an intravenous injection, polyethylene glycol chains (PEG 750 Hemocompatibility tests showed no effect of these polyplexes on hemolysis and coagulation. In vivo biodistribution in mice was performed and showed a better siRNA accumulation at the tumor site for PEGylated polyplexes. However, cellular uptake in protein-rich conditions showed that PEGylated polyplex lost their ability to interact with biological membranes and enter into cells, showing the importance to perform in vitro investigations in physiological conditions closed to in vivo situation. In vitro, the efficiency of PEGylated nanoparticles decreases compared to non-PEGylated particles, leading to the loss of the antiproliferative effect on cancer cells.

No abstract

The US FDA approval of broad-spectrum histone deacetylase (HDAC) inhibitors has firmly laid the cancer community to explore HDAC inhibition as a therapeutic approach for cancer treatment. Hitting one HDAC member could yield clinical benefit but this required a complete understanding of the functions of the different HDAC members. Here we explored the consequences of specific HDAC5 inhibition in cancer cells. We demonstrated that HDAC5 inhibition induces an iron-dependent reactive oxygen species (ROS) production, ultimately leading to apoptotic cell death as well as mechanisms of mitochondria quality control (mitophagy and mitobiogenesis). Interestingly, adaptation of HDAC5-depleted cells to oxidative stress passes through reprogramming of metabolic pathways towards glucose and glutamine. Therefore, interference with both glucose and glutamine supply in HDAC5-inhibited cancer cells significantly increases apoptotic cell death and reduces tumour growth in vivo; providing insight into a valuable clinical strategy combining the selective inhibition of HDAC5 with various inhibitors of metabolism as a new therapy to kill cancer cells.

Small interfering RNA (siRNA) inducing gene silencing has great potential to treat many human diseases. To ensure effective siRNA delivery, it must be complexed with an appropriate vector, generally nanoparticles. The nanoparticulate complex requires an optimal physiochemical characterization and the complexation efficiency has to be precisely determined. The methods usually used to measure complexation in gel electrophoresis and RiboGreen fluorescence-based assay. However, those approaches are not automated and present some drawbacks such as the low throughput and the use of carcinogenic reagents. The aim of this study is to develop a new simple and fast method to accurately quantify the complexation efficiency. In this study, capillary electrophoresis (CE) was used to determine the siRNA complexation with cationic liposomes. The short-end injection mode applied enabled siRNA detection in less than 5 min. Moreover, the CE technique offers many advantages compared with the other classical methods. It is automated, does not require sample preparation and expensive reagents. Moreover, no mutagenic risk is associated with the CE approach since no carcinogenic product is used. Finally, this methodology can also be extended for the characterization of other types of nanoparticles encapsulating siRNA, such as cationic polymeric nanoparticles.

No abstract

Hospital stay and mortality are increased in patients having a 'triple low' of low blood pressure, low bispectral index, and low minimum alveolar concentration of volatile anesthesia.

No abstract