Huntington’s disease (HD) is a monogenic disorder, caused by mutations in the HTT gene which result in expansion of CAG triplets. The product of the mutated gene is misfolded huntingtin protein that forms aggregates leading to impairment of neuronal function, neurodegeneration, motor abnormalities and cognitive deficits. No effective cure is currently available for HD. Here we studied effects of genistein (trihydroxyisoflavone) on a HD cellular model consisting of HEK-293 cells transfected with a plasmid bearing mutated HTT gene. Both level of mutated huntingtin and number of aggregates were significantly decreased in genistein-treated HD cell model. This led to increased viability of the cells. Autophagy was up-regulated while inhibition of lysosomal functions by chloroquine impaired the genistein-mediated degradation of the mutated huntingtin aggregates. Hence, we conclude that through stimulating autophagy, genistein removes the major pathogenic factor of HD. Prolonged induction of autophagy was suspected previously to be risky for patients due to putative adverse effects; however, genistein has been demonstrated recently to be safe and suitable for long-term therapies even at doses as high as 150 mg/kg/day. Therefore, results presented in this report provide a basis for the use of genistein in further studies on development of the potential treatment of HD.

Purpose Isothiocyanates (ITCs) are compounds derived from Brassica plants with documented anticancer activity. Molecular mechanisms of their selective activity against cancer cells are still underexplored. In this work, the impact of ITC on DNA replication and damage was compared between PC-3 prostate cancer cells and HDFa normal fibroblasts as well as PNT2 prostate epithelial cells. Methods Cells were treated with sulforaphane or phenethyl isothiocyanate. [³H]thymidine incorporation and the level of histone γH2A.X were estimated as indicators of DNA replication and double-strand breaks (DSB), respectively. Levels of HDAC3, CtIP, and p-RPA were investigated by immunoblotting. Comet assay was performed to visualize DNA damage. Results ITCs inhibited DNA replication in all tested cell lines, and this activity was independent of reactive oxygen species of mitochondrial origin. It was followed by DSB which were more pronounced in cancer than noncancerous cells. This difference was independent of HDAC activity which was decreased in both cell lines when treated with ITCs. On the other hand, it correlated with faster removal of DSB, and thus, transient activation of repair proteins in normal cells, while in PC-3 prostate cancer, cell DNA repair was significantly less effective. Conclusion DNA damage induced by ITCs is a consequence of the block in DNA replication which is observed in both, cancer and normal cells. Selective antiproliferative activity of ITCs towards cancer cells results from less efficient DNA repair in cancer cells relative to normal cells.

Derivatives of usnic acid (UA), a secondary metabolite from lichens, were synthesized to improve its anticancer activity and selectivity. Recently we reported the synthesis and activity of an UA isoxazole derivative, named 2b, against cancer cells of different origins. Herein, the molecular mechanisms underlying its activity and efficacy in vivo were tested. The viability of breast cancer or normal cells has been tested using an MTT assay. Cell and organelle morphology was analyzed using light, electron and fluorescence microscopy. Gene expression was evaluated by RNAseq and protein levels were evaluated by Western blotting. In vivo anticancer activity was evaluated in a mice xenograft model. We found that 2b induced massive vacuolization which originated from the endoplasmic reticulum (ER). ER stress markers were upregulated both at the mRNA and protein levels. ER stress was caused by the release of Ca²⁺ ions from the ER by IP3R channels which was mediated, at least partly, by phospholipase C (PLC)-synthetized 1,4,5-inositol triphosphate (IP3). ER stress led to cell death with features of apoptosis and paraptosis. When applied to nude mice with xenografted breast cancer cells, 2b stopped tumour growth. In mice treated with 2b, vacuolization was observed in tumour cells, but not in other organs. This study shows that the antiproliferative activity of 2b relates to the induction of ER stress in cancer, not in healthy, cells and it leads to breast cancer cell death in vitro and in vivo.