Celecoxib, a COX-2 inhibitor, synergistically potentiates the anti-inflammatory activity of docosahexaenoic acid in macrophage cell line.

BACKGROUND: The anti-inflammatory properties of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and non-steroidal anti-inflammatory drugs overlap in many ways. The aim of this study was to examine the individual and synergetic anti-inflammatory effects of celecoxib, EPA and DHA in RAW-264.7 cell line. METHODOLOGY: The cells were exposed to EPA, DHA, celecoxib, rosiglitazone, GW9662 alone or their combination, and stimulated with 5 µg/mL lipopolysaccharide (LPS). Nitric oxide (NO), tumor necrosis factor-α (TNF-α), interleukin (IL)-6 and prostaglandin-E2 (PGE2) levels were estimated in the medium using enzyme-linked immunosorbent assays. The cyclooxygenase-2 (COX-2) and inducible Nitric Oxide Synthase (iNOS) expression were analyzed in the cell lysate by immunoblotting. Peroxisome proliferator-activated receptor γ (PPARγ) and nuclear factor-κB (NF-κB) transcription factor activation assays were performed in the nuclear extract. RESULTS: Combined treatment of DHA (50 µM) and celecoxib (20 µM) significantly inhibited LPS induced synthesis of NO, TNF-α, IL-6 and PGE2 levels in the cells, compared to the individual treatments. In addition, DHA and celecoxib diminished the COX-2 and iNOS expression in the cells. This was associated with increased PPARγ activity, supressed NF-κB activity in the nucleus. We determined whether GW9662, a specific PPARγ inhibitor, could abolish the anti-inflammatory effect of DHA and celecoxib. GW9662 has abolished the DHA and celecoxib induced PPARγ activation, but did not alter the NF-κB mediated anti-inflammatory effects induced by celecoxib and DHA. Interestingly, EPA did not exhibit any inhibitory effect on these parameters. CONCLUSION: Our results suggest that DHA and celecoxib exhibit anti-inflammatory effect through inhibition of NF-κB, independent of PPARγ. Co-administration of celecoxib and DHA would be promising approach for the treatment of inflammatory diseases.

Distinct roles of different forms of vitamin E in DHA-induced apoptosis in triple-negative breast cancer cells.

SCOPE: Docosahexaenoic acid (DHA) has been shown to exhibit anticancer actions in vitro and in vivo in a variety of cancers. Here, we investigated the role for DHA in inducing apoptosis in triple-negative breast cancer (TNBC) and studied the mechanisms of action. METHODS AND RESULTS: DHA induces apoptosis as detected by Annexin V-FITC/PI assay as well as induces cleavage of caspase-8 and -9, endoplasmic reticulum stress (ERS), and elevated levels of death receptor-5 (DR5) protein expression as detected by western blot assays. Chemical inhibitors of caspase-8 and -9 and small interfering RNAs (siRNAs) show DHA to induce ERS/CHOP/DR5-mediated caspase-8 and -9 dependent apoptosis. Furthermore, DHA induces elevated cellular levels of reactive oxygen species (ROS) and antioxidant; RRR-α-tocopherol (αT) blocked DHA-induced apoptotic events. In contrast to the antagonistic impact of αT, gamma-tocotrienol (γT3) was demonstrated to cooperate with DHA in inducing apoptotic events in TNBC cells. CONCLUSION: Data, for the first time, demonstrate that DHA induces apoptosis in TNBC cells via activation of ERS/CHOP/DR5-mediated caspase-8 and -9 dependent pro-apoptotic events, and that different forms of vitamin E exhibit distinct effects on DHA-induced apoptosis; namely, inhibition by αT and enhancement by γT3.

Fenretinide promotes functional recovery and tissue protection after spinal cord contusion injury in mice.

The inflammatory response is thought to contribute to secondary damage after spinal cord injury (SCI). Polyunsaturated fatty acids (PUFAs) play an important role in the onset and resolution of inflammation. Arachidonic acid (AA), an omega-6 PUFA, contributes to the initiation of inflammatory responses, whereas docosahexaenoic acid (DHA), an omega-3 PUFA, has antiinflammatory effects. Therefore, decreasing AA and increasing DHA levels after SCI might be expected to attenuate inflammation after SCI and promote tissue protection and functional recovery. We show here that daily oral administration of fenretinide after spinal cord contusion injury led to a significant decrease in AA and an increase in DHA levels in plasma and injured spinal cord tissue. This was accompanied by a significant reduction in tissue damage and improvement in locomotor recovery. Fenretinide also reduced the expression of proinflammatory genes and the levels of oxidative stress markers after SCI. In addition, in vitro studies demonstrated that fenretinide reduced TNF-alpha (tumor necrosis factor-alpha) expression by reactive microglia. These results demonstrate that fenretinide treatment after SCI can reduce inflammation and tissue damage in the spinal cord and improve locomotor recovery. These beneficial effects may be mediated via the ability of fenretinide to modulate PUFA homeostasis. Since fenretinide is currently in clinical trials for the treatment of cancers, this drug might be a good candidate for the treatment of acute SCI in humans.