Role of calcium-induced mitochondrial hydroperoxide in induction of apoptosis of RBL2H3 cells with eicosapentaenoic acid treatment

EPA plays multiple roles in regulating lipid accumulation of grass carp Ctenopharyngodon idella adipose tissue in vitro and in vivo

This study was conducted to assess the effect of eicosapentaenoic acid (20:5n-3, EPA) on lipid accumulation in grass carp Ctenopharyngodon idella adipose tissue both in vitro and in vivo. EPA was observed to inhibit the adipocyte viability in a time and dose-dependent manner. EPA was also found to induce reactive oxygen species accumulation in vitro. The mRNA levels of caspase 3a and caspase 3b, as well as the activity of Caspase 3 increased significantly in vitro and in vivo, whereas the value of B cell leukemia 2-Bcl-2 associated X protein decreased significantly. Besides, the pro-apoptotic effect was relieved by α-tocopherol. Dietary 0.52% EPA had no apparent effect on intraperitoneal fat index. Moreover, EPA promoted the hydrolytic gene expressions in vitro and in vivo, including adipose triglyceride lipase and hormone sensitive lipase-a. Meanwhile, the lipogenic gene expressions of liver X receptor α, sterol regulatory element binding protein-1c and fatty-acid synthase were down-regulated by EPA in vitro and in vivo. However, EPA also acted to promote the marker gene expressions of adipogenesis, including peroxisome proliferator-activated receptor γ and lipoprotein lipase in vitro and in vivo. Contents of EPA increased significantly in the treatment groups in vitro and in vivo. These results support that EPA affects multiple aspects of lipid metabolism, including hydrolysis, lipogenesis, adipogenesis and apoptosis. However, it barely functioned in decreasing the lipid accumulation of Ctenopharyngodon idella under the current culture conditions.

Effects of the polyunsaturated fatty acids, EPA and DHA, on hematological malignancies: a systematic review

Omega-3 polyunsaturated fatty acids (PUFAs) have well established anti-cancer properties. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are among this biologically active family of macromolecules for which various anti-cancer effects have been explained. These PUFAs have a high safety profile and can induce apoptosis and inhibit growth of cancer cells both in vitro and in vivo, following a partially selective manner. They also increase the efficacy of chemotherapeutic agents by increasing the sensitivity of different cell lines to specific anti-neoplastic drugs. Various mechanisms have been proposed for the anti-cancer effects of these omega-3 PUFAs; however, the exact mechanisms still remain unknown. While numerous studies have investigated the effects of DHA and EPA on solid tumors and the responsible mechanisms, there is no consensus regarding the effects and mechanisms of action of these two FAs in hematological malignancies. Here, we performed a systematic review of the beneficial effects of EPA and DHA on hematological cell lines as well as the findings of related in vivo studies and clinical trials. We summarize the key underlying mechanisms and the therapeutic potential of these PUFAs in the treatment of hematological cancers. Differential expression of apoptosis-regulating genes and Glutathione peroxidase 4 (Gp-x4), varying abilities of different cancerous and healthy cells to metabolize EPA into its more active metabolites and to uptake PUFAS are among the major factors that determine the sensitivity of cells to DHA and EPA. Considering the abundance of data on the safety of these FAs and their proven anti-cancer effects in hematological cell lines and the lack of related human studies, further research is warranted to find ways of exploiting the anticancer effects of DHA and EPA in clinical settings both in isolation and in combination with other therapeutic regimens.

Digitoxin and its analogs as novel cancer therapeutics

A growing body of evidence indicates that digitoxin cardiac glycoside is a promising anticancer agent when used at therapeutic concentrations. Digitoxin has a prolonged half-life and a well-established clinical profile. New scientific avenues have shown that manipulating the chemical structure of the saccharide moiety of digitoxin leads to synthetic analogs with increased cytotoxic activity. However, the anticancer mechanism of digitoxin or synthetic analogs is still subject to study while concerns about digitoxin's cardiotoxicity preclude its clinical application in cancer therapeutics. This review focuses on digitoxin and its analogs, and their cytotoxicity against cancer cells. Moreover, a new perspective on the pharmacological aspects of digitoxin and its analogs is provided to emphasize new research directions for developing potent chemotherapeutic drugs.

Reactive oxygen species are key mediators of the nitric oxide apoptotic pathway in anterior pituitary cells

We previously showed that long-term exposure of anterior pituitary cells to nitric oxide (NO) induces apoptosis. The intracellular signals underlying this effect remained unclear. In this study, we searched for possible mechanisms involved in the early stages of the NO apoptotic cascade. Caspase 3 was activated by NO with no apparent disruption of mitochondrial membrane potential. NO caused a rapid increase of reactive oxygen species (ROS), and this increase seems to be dependent of mitochondrial electron transport chain. The antioxidant N-acetyl-cysteine avoided ROS increase, prevented the NO-induced caspase 3 activation, and reduced the NO apoptotic effect. Catalase was inactivated by NO, while glutathione peroxidase (GPx) activity and reduced glutathione (GSH) were not modified at first, but increased at later times of NO exposure. The increase of GSH level is important for the scavenging of the NO-induced ROS overproduction. Our results indicate that ROS have an essential role as a trigger of the NO apoptotic cascade in anterior pituitary cells. The permanent inhibition of catalase may strengthen the oxidative damage induced by NO. GPx activity and GSH level augment in response to the oxidative damage, though this increase seems not to be enough to rescue the cells from the NO effect.

Mitochondrial membrane dynamics, cristae remodelling and apoptosis

Mitochondria form a highly dynamic reticular network in living cells, and undergo continuous fusion/fission events and changes in ultrastructural architecture. Although significant progress has been made in elucidating the molecular events underlying these processes, their relevance to normal cell function remains largely unexplored. Emerging evidence, however, suggests an important role for mitochondrial dynamics in cellular apoptosis. The mitochondria is at the core of the intrinsic apoptosis pathway, and provides a reservoir for protein factors that induce caspase activation and chromosome fragmentation. Additionally, mitochondria modulate Ca2+ homeostasis and are a source of various metabolites, including reactive oxygen species, that have the potential to function as second messengers in response to apoptotic stimuli. One of the mitochondrial factors required for activation of caspases in most intrinsic apoptotic pathways, cytochrome c, is largely sequestered within the intracristae compartment, and must migrate into the boundary intermembrane space in order to allow passage across the outer membrane to the cytosol. Recent evidence argues that inner mitochondrial membrane dynamics regulate this process. Here, we review the contribution of mitochondrial dynamics to the intrinsic apoptosis pathway, with emphasis on the inner membrane.