Tenofovir alafenamide (TAF) is a new drug from the nucleotide reverse transcriptase inhibitor group approved for the treatment of chronic Hepatitis B in 2016. With this study, we aimed to test whether possible cellular toxicity can be reduced by controlled drug release as a result of loading with chitosan nanoparticles (CHS). We investigated the genotoxic and mitotoxic effects of 45 µM TAF-loaded CHS and TAF-only on HepG2 cells by micronucleus (MN), comet assay, determination of mtDNA quantification, mitochondrial membrane potential (ΔΨm), and ROS levels. Additionally, we compared the samples by RNAseq analyses to reveal the transcriptional responses to each regimen. In terms of genotoxic tests, although MN and comet were found higher in all experimental treatment conditions, the encapsulation of CHS reduced the genotoxicity of TAF. MtDNA level was found to be lower in the TAF treatment, whereas it was higher in CHS and CHS-TAF treatments. The TAF-loaded CHS and TAF treatments had an impaired ΔΨm value. Cellular ROS levels were higher in all treatment conditions. According to the analyses of gene expression patterns; CHS-only changed the expression of relatively few genes (187 genes), while TAF changed the expression of the 1974 genes and TAF-loaded CHS changed the expression of 734 genes. Considering the gene expression numbers, CHS encapsulation of TAF significantly reduced the number of genes that were differentially expressed by TAF-only. Overall, we observed that TAF has genotoxic and mitotoxic effects on HepG2 cells, and upon encapsulation with CHS, its genotoxic and mitotoxic effects were decreased.
Keywords: Word; controlled drug release; cytotoxicity; genotoxicity; mitochondrial toxicity; pharmaceutical toxicology; tenofovir alafenamide.