HA-1077 observed a biphasic effect of Resveratrol on cell viability of ECV304 cells, since at high concentrations it has induced death cell, whereas at low concentrations it has not and also protected them from oxidative stress. In addition, Resveratrol at low doses modulated the secretion of NO and PGE2 by ECV304 cells and played an anti adhesion activity of neutrophils on PMA activated cells. Cell viability of bladder carcinoma cell line ECV304 was evalu ated by MTT assay and flow cytometry in the presence of different Resveratrol concentrations. ECV304 cells present some advantages for this study: they are a derivation from thehuman bladder carcinoma T24 cell line, produce some inflam matory mediators, appropriated for metabolism studies and are easily maintained in vitro culture. Our data show that, at low concentrations, Resveratrol decreases neither cell viability nor DNA content, and does not induce a significantly cell permeability. On the other hand, at highest concentrations tested, it was able to decrease the cell growth antimetabolites such as the DNA content and to increase the percentage of cells that present perme ability, i.e, signals of death cell. This biphasic effect of Resveratrol already has been demonstrated to other kind of cells, including nor mal and cancer cells.
In prostate cancer cells, the effect of Resveratrol PLK on DNA synthesis varied dramatically, depending on the concentration and the duration of treatment. Using an extended treatment it was observed a dual effect of Resveratrol on DNA syn thesis. At 5 10 M it caused a 2 to 3 fold increase in DNA synthesis, and at 15 M, it inhibited DNA synthesis. A second study reported that low doses of Resveratrol enhance cell proliferation, higher doses induce apoptosis and decrease mitotic activity in colon cancer cells and endothe lial cells. Together, our results clearly corroborate with other previous ones about the importance of concentration to diverse activities of Resveratrol. Moreover, we have added new informa tion about the effects of Resveratrol on bladder cancer cells since this polyphenol can induce or not these cells to die, depending on the dose used in a particular situation. In an effort to try to understand better the effects of low concentrations of Resveratrol on bladder carcinoma cell line ECV304 we have investigated its antioxidant role on these cells. Resveratrol at low abiraterone concentration was suited to play a protective effect on ECV304 cells from damage induced by oxida tive stress.
These conclusions were constructed from PI staining, DNA content, phophatidylserine exposure and DNA fragmentation assays. Interestingly, Resveratrol has induced release of nitric oxide from ECV304 cells. Reactive oxygen species have been regarded as toxic products of metabolism because of their damaging effects on structural and functional molecules that, eventually, result in apoptosis potential and uncontrolled proliferation. Although, Resveratrol has induced secretion of ROS from ECV304, it protected them from exogenous oxidative stress such as other natural antioxidants from vegetable foods that can counteract the effects of ROS. Our group has demonstrated previously that soy extracts are also apt to activate NO synthesis in ECV304 cells and to protect them against cell damage.