interleukin-8 and thymoquinone

Gestational diabetes mellitus (GDM) not only has short-term side effects on offspring but also has an increased risk of developing chronic diseases in adulthood. The thymus gland is a vital organ of immune system and thymoquinone (TQ) has an immunomodulatory effect. This study aimed to investigate the long-term adverse effects of GDM on offspring's thymus gland and the ameliorating effect of TQ. Pregnant rats were divided into four groups: C-group, T-group, GD-group, and GD + T-group. Offspring of all groups were subdivided into two subgroups, one sacrificed on day 21 and the other on day 42. The thymus of the offspring in the GD-group at both time points revealed a significant decrease in thymic weight, superoxide dismutase (SOD), and reduced glutathione (GSH) levels with a significant increase in malondialdehyde (MDA), interleukin-8 (IL-8), and tumor necrosis factor-alpha (TNF-α) levels. Moreover, there were microscopic degenerative changes, a significant decrease in C/M ratio, CD3, CD4, and CD8 immune expression, and a significant increase in activated caspase-3 immune expression. Interestingly, TQ administration revealed a significant increase in thymic weight, thymic SOD and GSH, C/M ratio, and CD3, CD4, and CD8 immune expression with a significant decrease in MDA, IL-8, TNF-α and activated caspase-3. For the first time, this study has shown that GDM causes long-term oxidative stress, apoptosis, and inflammation in offspring's thymus and these changes could be attenuated by TQ.

Topics: Animals; Caspase 3; Diabetes, Gestational; Female; Humans; Interleukin-8; Pregnancy; Rats; Superoxide Dismutase; Thymus Gland; Tumor Necrosis Factor-alpha

Medulloblastoma (MB) is the most common malignant brain tumor of childhood. The transcription factor NF-κB is overexpressed in human MB and is a critical factor for MB tumor growth. NF-κB is known to regulate the expression of interleukin-8 (IL-8), the chemokine that enhances cancer cell growth and resistance to chemotherapy. We have recently shown that thymoquinone (TQ) suppresses growth of hepatocellular carcinoma cells in part by inhibiting NF-κB signaling. Here we sought to extend these studies in MB cells and show that TQ suppresses growth of MB cells in a dose- and time-dependent manner, causes G2M cell cycle arrest, and induces apoptosis. TQ significantly increased generation of reactive oxygen species (ROS), while pretreatment of MB cells with the ROS scavenger N-acetylcysteine (NAC) abrogated TQ-induced cell death and apoptosis, suggesting that TQ-induced cell death and apoptosis are oxidative stress-mediated. TQ inhibitory effects were associated with inhibition of NF-κB and altered expression of its downstream effectors IL-8 and its receptors, the anti-apoptotic Bcl-2, Bcl-xL, X-IAP, and FLIP, as well as the pro-apoptotic TRAIL-R1, caspase-8, caspase-9, Bcl-xS, and cytochrome c. TQ-triggered apoptosis was substantiated by up-regulation of the executioner caspase-3 and caspase-7, as well as cleavage of the death substrate poly(ADP-ribose)polymerase. Interestingly, pretreatment of MB cells with NAC or the pan-caspase inhibitor zVAD-fmk abrogated TQ-induced apoptosis, loss of cyclin B1 and NF-κB activity, suggesting that these TQ-mediated effects are oxidative stress- and caspase-dependent. These findings reveal that TQ induces both extrinsic and intrinsic pathways of apoptosis in MB cells, and suggest its potential usefulness in the treatment of MB.

Topics: Apoptosis; Benzoquinones; Caspases; Cell Line, Tumor; Gene Expression Regulation, Neoplastic; Humans; Interleukin-8; Medulloblastoma; Neoplasm Proteins; NF-kappa B; Oxidative Stress; Signal Transduction

Tumor necrosis factor-α (TNF-α) is a pro-inflammatory cytokine produced by monocytes/macrophage that plays a pathological role in rheumatoid arthritis (RA). In this study, we investigate the effect of thymoquinone (TQ), a phytochemical found in Nigella sativa, in regulating TNF-α-induced RA synovial fibroblast (RA-FLS) activation. Treatment with TQ (1-5μM) had no marked effect on the viability of human RA-FLS. Pre-treatment of TQ inhibited TNF-α-induced interleukin-6 (IL-6) and IL-8 production and ICAM-1, VCAM-1, and cadherin-11 (Cad-11) expression in RA-FLS (p<0.01). Evaluation of the signaling events showed that TQ inhibited TNF-α-induced phospho-p38 and phospho-JNK expression, but had no inhibitory effect on NF-κB pathway, in RA-FLS (p<0.05; n=4). Interestingly, we observed that selective down-regulation of TNF-α-induced phospho-p38 and phospho-JNK activation by TQ is elicited through inhibition of apoptosis-regulated signaling kinase 1 (ASK1). Furthermore, TNF-α selectively induced phosphorylation of ASK1 at Thr845 residue in RA-FLS, which was inhibited by TQ pretreatment in a dose dependent manner (p<0.01). Pre-treatment of RA-FLS with ASK1 inhibitor (TC ASK10), blocked TNF-α induced expression of ICAM-1, VCAM-1, and Cad-11. Our results suggest that TNF-α-induced ASK1-p38/JNK pathway is an important mediator of cytokine synthesis and enhanced expression of adhesion molecule in RA-FLS and TQ, by selectively inhibiting this pathway, may have a potential therapeutic value in regulating tissue destruction observed in RA.

Topics: Anti-Inflammatory Agents; Arthritis, Rheumatoid; Benzoquinones; Cell Adhesion; Cell Adhesion Molecules; Cells, Cultured; Dose-Response Relationship, Drug; Enzyme Activation; Extracellular Signal-Regulated MAP Kinases; Fibroblasts; Humans; Inflammation Mediators; Interleukin-6; Interleukin-8; MAP Kinase Kinase Kinase 5; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Signal Transduction; Synovial Membrane; Tumor Necrosis Factor-alpha

Hepatocellular carcinoma (HCC) is the fourth most common solid tumor worldwide. The chemokine interleukin-8 (IL-8) is overexpressed in HCC and is a potential target for therapy. Although the transcription factor NF-κB regulates IL-8 expression, and while thymoquinone (TQ; the most bioactive constituent of black seed oil) inhibits NF-κB activity, the precise mechanisms by which TQ regulates IL-8 and cancer cell growth remain to be clarified. Here, we report that TQ inhibited growth of HCC cells in a dose- and time-dependent manner, caused G2M cell cycle arrest, and stimulated apoptosis. Apoptosis was substantiated by activation of caspase-3 and -9, as well as cleavage of poly(ADP-ribose)polymerase. TQ treatments inhibited expression of NF-κB and suppressed IL-8 and its receptors. TQ treatments caused increased levels of reactive oxygen species (ROS) and mRNAs of oxidative stress-related genes, NQO1 and HO-1. Pretreatment of HepG2 cells with N-acetylcysteine, a scavenger of ROS, prevented TQ-induced cell death. TQ treatment stimulated mRNA expression of pro-apoptotic Bcl-xS and TRAIL death receptors, and inhibited expression of the anti-apoptotic gene Bcl-2. TQ enhanced TRAIL-induced death of HepG2 cells, in part by up-regulating TRAIL death receptors, inhibiting NF-κB and IL-8 and stimulating apoptosis. Altogether, these findings provide insights into the pleiotropic molecular mechanisms of TQ-dependent suppression of HCC cell growth and underscore potential of this compound as anti-HCC drug.

Topics: Apoptosis; bcl-X Protein; Benzoquinones; Carcinoma, Hepatocellular; Caspase 3; Caspase 9; Cell Line, Tumor; Cell Proliferation; G2 Phase Cell Cycle Checkpoints; Hep G2 Cells; Humans; Interleukin-8; Liver Neoplasms; M Phase Cell Cycle Checkpoints; NF-kappa B; Oxidative Stress; Poly(ADP-ribose) Polymerases; Proto-Oncogene Proteins c-bcl-2; Reactive Oxygen Species; Receptors, TNF-Related Apoptosis-Inducing Ligand