ABSTRACT
Akt activation assists tumor cell survival and promotes resistance to chemotherapy. Here we show that constitutively active Akt (CA-Akt) cells are highly sensitized to cell death induced by nutrient and growth factor deprivation, whereas dominant-negative Akt (DN-Akt) cells have a high rate of survival. The content of autophagosomes in starved CA-Akt cells was high, while DN-Akt cells expressed autophagic vacuoles constitutively, independently of nutrition conditions. Thus Akt down-regulation and downstream events can induce autophagosomes which were not directly determinants of cell death. Biochemical analysis in Akt-mutated cells show that (i) Akt and mTOR proteins were degraded more rapidly than the housekeeping proteins, (ii) mTOR phosphorylation at position Thr(2446) was relatively high in DN-Akt and low in CA-Akt cells, induced by starvation in mock cells only, which suggests reduced autoregulation of these pathways in Akt-mutated cells, (iii) both protein synthesis and protein degradation were significantly higher in starved CA-Akt cells than in starved DN-Akt cells or mock cells. In conclusion, constitutively active Akt, unable to control synthesis and wasting of proteins, accelerates the death of starved cells.
Subject(s)
Apoptosis , Proto-Oncogene Proteins c-akt/metabolism , Autophagy , Cell Line , Cell Survival , Culture Media, Serum-Free , Humans , Mutation , Protein Biosynthesis , Protein Kinases/metabolism , Proteins/metabolism , Proto-Oncogene Proteins c-akt/genetics , TOR Serine-Threonine Kinases , Vacuoles/metabolismABSTRACT
In modern industrial societies the attention to public health, especially in relation to food habits, is increasing day by day. Considering this, it's no wonder that wine, the voluptuary drink that best represents human history, is the most interesting compound. The main and best known wine effects on the human body are caused by alcohol, but several other active compounds are present in wine. Above all, resveratrol is able to neutralize free radicals, which can damage DNA and may lead to cancer onset. In this study, we have indagated resveratrol anticancer action, analyzing its effects on both cell cycle and growing of human lymphoma B (DHL-4) cells. MTT colorimetric test, tripan blue dye exclusion assay, and cell cycle analysis showed that resveratrol has a dose-dependent antiproliferative and antiapoptotic action on DHL-4 cells. These results confirm resveratrol's potential therapeutic role on tumors.
