PKR-IN-C16

PKR-IN-C16 suppresses proliferation of HCC cells in a dose-dependent manner in vitro. Transcript levels of vascular endothelial growth factor-A and factor-B, platelet-derived growth factor-A and factor-B, fibroblast growth factor-2, epidermal growth factor, and hepatocyte growth factor, which are angiogenesis-related growth factors, are significantly decreased by PKR-IN-C16 in vitro. PKR-IN-C16 blockes tumor cell growth and angiogenesis via a decrease in mRNA levels of several growth factors.^[2]

In vitro cell viability is quantified with the MTS assay. Huh7 cells treated with several concentrations (500–3000  nM) of the PKR inhibitor are seeded in 96-well plates at 2 × 10³ cells per well. At each time point, cells are treated with MTS reagent and incubated for 120 min. Absorbance at 450 nm is recorded. Cells treated with DMSO are used as controls. The wells are photographed under the microscope.

Inflammation is induced by unilateral striatal injection of quinolinic acid (QA) in 10-week-old normotensive rats. The highest dose of C16 (600 μg/kg; C16-2) in QA rats reduces expression of the active catalytic domain of the PKR vs. that in vehicle-injected QA rats. A robust increase of IL-1b levels on the contralateral side of QA rats is prevented by C16-2 (97% inhibition). Macroscopic and microscopic observation of cerebral tissue revealed that tissue integrity is more preserved with C16-2 treatment than its vehicle in QA rats. Furthermore, C16-2 treatment decreases by 47% the neuronal loss and by 37% the number of positive cleaved caspase-3 neurons induced by QA injection. In conclusion, C16 prevents not only the PKR-induced neuronal loss but also the inflammatory response in this acute excitotoxic in vivo model, highlighting its promising neuroprotective properties to rescue acute brain lesions.^[1]