15d-PGJ2 inhibits NF-?B and AP-1-mediated MMP-9 expression and invasion of breast cancer cell by means of a heme oxygenase-1-dependent mechanism.
ABSTRACT: Activation of peroxisome proliferator-activated receptor ? (PPAR?) serves as a key factor in the proliferation and invasion of breast cancer cells and is a potential therapeutic target for breast cancer. However, the mechanisms underlying this effect remain largely unknown. Heme oxygenase-1 (HO-1) is induced and overexpressed in various cancers and is associated with features of tumor aggressiveness. Recent studies have shown that HO-1 is a major downstream target of PPAR?. In this study, we investigated the effects of induction of HO-1 by PPAR? on TPAinduced MMP-9 expression and cell invasion using MCF-7 breast cancer cells. TPA treatment increased NF-?B /AP-1 DNA binding as well as MMP-9 expression. These effects were significantly blocked by 15d-PGJ2, a natural PPAR? ligand. 15d-PGJ2 induced HO-1 expression in a dose-dependent manner. Interestingly, HO-1 siRNA significantly attenuated the inhibition of TPA-induced MMP-9 protein expression and cell invasion by 15d-PGJ2. These results suggest that 15d-PGJ2 inhibits TPA-induced MMP- 9 expression and invasion of MCF-7 cells by means of a heme oxygenase-1-dependent mechanism. Therefore, PPAR?/HO-1 signaling- pathway inhibition may be beneficial for prevention and treatment of breast cancer. [BMB Reports 2020; 53(4): 212-217].
Project description:HO-1 (haem oxygenase 1) is an essential antioxidant enzyme in the cell that exerts its effects through removal of pro-oxidant haem groups and the formation of antioxidant molecules and carbon monoxide. The electrophilic cyclopentenone 15d-PGJ2 (15-deoxy-Delta(12,14)-prostaglandin J2) induces the expression of HO-1 protein through the covalent modification of protein thiols. It has been shown that specific thiol residues of the redox-sensor Keap1 (Kelch-like ECH-associated protein 1) are modified by 15d-PGJ2, leading to activation of the transcription factor Nrf-2 (nuclear factor-erythroid 2 p45 subunit-related factor 2) and up-regulation of genes under control of the electrophile-response element, including HO-1. However, 15d-PGJ2 has also been shown to modify other proteins which comprise the electrophile-responsive proteome. Since 15d-PGJ2 has been shown to localize to the mitochondria in endothelial cells, we hypothesized that mitochondrial protein modification may also be important in Keap1/Nrf-2 signal transduction, leading to HO-1 up-regulation. In order to determine the role of mitochondrial protein thiol modification in HO-1 induction, we used the mitochondrial-targeted thiol-reactive compound IBTP [(4-iodobutyl)triphenylphosphonium]. IBTP had no effect on basal HO-1 levels, but effectively blocked HO-1 induction by a variety of reagents including haemin, iodoacetamide and 15d-PGJ2. Mechanistically, IBTP did not prevent the covalent modification of Keap1 by 15d-PGJ2. However, IBTP prevented the 15d-PGJ2-dependent increases in HO-1 mRNA and protein. Furthermore, IBTP prevented the nuclear accumulation of Nrf-2, suggesting cross-talk between mitochondria and antioxidant-response signal transduction. This effect was independent of reactive oxygen species formation or mitochondrial membrane potential. In addition, IBTP significantly enhanced the toxicity of high concentrations of 15d-PGJ2, suggesting that loss of mitochondrial control of HO-1 leads to increased susceptibility to electrophilic stress in endothelial cells. The implications for these studies in understanding the balance between cytoprotection and cytotoxicity in the context of diseases such as atherosclerosis is discussed.
Project description:MMP-1 expression is detected in fluid shear stress (20 dyn/cm(2))-activated and osteoarthritic human chondrocytes, however, the precise mechanisms underlying shear-induced MMP-1 synthesis remain unknown. Using primary chondrocytes and T/C-28a2 chondrocytic cells as model systems, we report that prolonged application of high fluid shear to human chondrocytes induced the synthesis of cyclooxygenase-2 (COX-2), interleukin-1? (IL-1?) and fibroblast growth factor-2 (FGF-2), which led to a marked increase in MMP-1 expression. IL-1?, COX-2-dependent PGE2 activated the PI3-K/AKT and p38 signaling pathways, which were in turn responsible for MMP-1 synthesis via NF-?B- and c-Jun-transactivating pathways. Prolonged shear stress exposure (>12 h) induced 15-Deoxy-?(12,14)-prostaglandin J2 (15d-PGJ2) synthesis. Although 15d-PGJ2 suppressed PI3-K/AKT and p38 signaling pathways, it stimulated MMP-1 expression via activating heme oxygenase 1 (HO-1). The critical role of COX-2 in regulating MMP-1 expression in articular cartilage in vivo was demonstrated using COX-2(+/-) transgenic mice in the absence or presence of rofecoxib oral administration. These findings provide novel insights for developing therapeutic strategies to combat OA.
Project description:Prototypical electrophiles such as the lipid 15-deoxy-Delta12,14-prostaglandin J2 (15d-PGJ2) are well recognized for their therapeutic potential. Electrophiles modify signalling proteins in both the cytosol and mitochondrion, which results in diverse cellular responses, including cytoprotective effects and, at high doses, cell death. These findings led us to the hypothesis that targeting electrophiles to specific compartments in the cell could fine-tune their biological effects. To examine this, we synthesized a novel mitochondrially targeted analogue of 15d-PGJ2 (mito-15d-PGJ2) and tested its effects on redox cell signalling. Mito-15d-PGJ2 caused profound defects in mitochondrial bioenergetics and mitochondrial membrane depolarization when compared with 15d-PGJ2. We also found that mito-15d-PGJ2 modified different members of the electrophile-responsive proteome, was more potent at initiating intrinsic apoptotic cell death and was less effective than 15d-PGJ2 at up-regulating the expression of HO-1 (haem oxygenase-1) and glutathione. These results demonstrate the feasibility of modulating the biological effects of electrophiles by targeting the pharmacophore to mitochondria.
Project description:Urinary obstruction is associated with inflammation and oxidative stress, leading to renal dysfunction. Previous studies have shown that 15-deoxy-?12,14-prostaglandin J2 (15d-PGJ2) has both antioxidant and anti-inflammatory effects. Using a unilateral ureteral obstruction (UUO) mouse model, we examined the effects of 15d-PGJ2 on oxidative stress and inflammation in the kidney. Mice were subjected to UUO for 3 days and treated with 15d-PGJ2. Protein and RNA expression were examined using immunoblotting and qPCR. 15d-PGJ2 increased NF-E2-related nuclear factor erythroid-2 (Nrf2) protein expression in response to UUO, and heme oxygenase 1 (HO-1), a downstream target of Nrf2, was induced by 15d-PGJ2. Additionally, 15d-PGJ2 prevented protein carbonylation, a UUO-induced oxidative stress marker. Inflammation, measured by nuclear NF-?B, F4/80, and MCP-1, was increased in response to UUO and further increased by 15d-PGJ2. Renal injury was aggravated by 15d-PGJ2 treatment as measured by kidney injury molecule-1 (KIM-1) and cortical caspase 3 content. No effect of 15d-PGJ2 was observed on renal function in mice subjected to UUO. This study illustrates differentiated functioning of 15d-PGJ2 on inflammation and oxidative stress in response to obstructive nephropathy. High concentrations of 15d-PGJ2 protects against oxidative stress during 3-day UUO in mice; however, it aggravates the associated inflammation.
Project description:Background:Abnormal upregulation of prostaglandin E2 (PGE2) is considered to be a key oncogenic event in the development and progression of inflammation-associated human colon cancer. It has been reported that 15-hydroxyprostaglandin dehydrogenase (15-PGDH), an enzyme catabolizing PGE2, is ubiquitously downregulated in human colon cancer. 15-Deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2), a peroxisome proliferator-activated receptor γ ligand, has been shown to have anticarcinogenic activities. In this study, we investigate the effect of 15d-PGJ2 on expression of 15-PGDH in human colon cancer HCT116 cells. Methods:HCT116 cells were treated with 15d-PGJ2 analysis. The expression of 15-PGDH in the treated cells was measured by Western blot analysis and RT-PCR. In addition, the cells were subjected to a 15-PGDH activity assay. To determine which transcription factor(s) and signaling pathway(s) are involved in 15d-PGJ2-induced 15-PGDH expression, we performed a cDNA microarray analysis of 15d-PGJ2-treated cells. The DNA binding activity of AP-1 was measured by an electrophoretic mobility shift assay. To determine whether the AP-1 plays an important role in the 15d-PGJ2-induced 15-PGDH expression, the cells were transfected with siRNA of c-Jun, a major subunit of AP-1. To elucidate the upstream signaling pathways involved in AP-1 activation by 15d-PGJ2, we examined its effect on phosphorylation of Akt by Western blot analysis in the presence or absence of kinase inhibitor. Results:15d-PGJ2 (10 μM) significantly upregulated 15-PGDH expression at the mRNA and protein levels in HCT-116 cells. 15-PGDH activity was also elevated by 15d-PGJ2. We observed that genes encoding C/EBP delta, FOS-like antigen 1, c-Jun, and heme oxygenase-1 (HO-1) were most highly induced in the HCT116 cells following 15d-PGJ2 treatment. 15d-PGJ2 increased the DNA binding activity of AP-1. Moreover, transfection with specific siRNA against c-Jun significantly reduced 15-PGDH expression induced by 15d-PGJ2. 15d-PGJ2 activates Akt and a pharmacological inhibitor of Akt, LY294002, abrogated 15d-PGJ2-induced 15-PGDH expression. We also observed that an inhibitor of HO-1, zinc protoporphyrin IX, also abrogated upregulation of 15-PGDH and down-regulation of cyclooxygenase-2 expression induced by 15d-PGJ2. Conclusions:These finding suggest that 15d-PGJ2 upregulates the expression of 15-PGDH through AP-1 activation in colon cancer HCT116 cells.
Project description:PPAR? belongs to the peroxisome proliferator-activated receptor (PPAR) family of nuclear receptors. Upon activation by an agonist, PPAR? controls a variety of physiological processes via regulation of its target genes. 15-Deoxy-?12,14-prostaglandin J2 (15d-PGJ2) is a cyclopentenone prostaglandin that features an electrophilic, ?,?-unsaturated ketone (an enone) in the cyclopentenone ring. Many of 15d-PGJ2's biological effects result from covalent interaction between C9 and the thiol group of a catalytic cysteine (Cys) in target proteins. In this study, we investigated whether 15d-PGJ2 activates PPAR? by forming a covalent adduct. Our data show that 15d-PGJ2 activates PPAR?'s transcriptional activity through formation of a covalent adduct between its endocyclic enone at C9 and Cys249 in the receptor's ligand-binding domain. As expected, no adduct formation was seen following a Cys-to-Ser mutation at residue 249 (C249S) of PPAR? or with a PGD2/PGJ2 analogue that lacks the electrophilic C9. Furthermore, the PPAR? C249S mutation weakened induction of the receptor's DNA binding activity by 15d-PGJ2, which highlights the biological significance of our findings. Calculated chemical properties as well as data from molecular orbital calculations, reactive molecular dynamics simulations, and intrinsic reaction coordinate modeling also supported the selectivity of 15d-PGJ2's C9 toward PPAR?'s Cys thiol. In summary, our results provide the molecular, chemical, and structural basis of 15d-PGJ2-mediated PPAR? activation, designating 15d-PGJ2 as the first covalent PPAR? ligand to be identified.
Project description:An endogenous anticancer agent, 15-deoxy -?12,14-prostaglandin J2 (15d-PGJ2) induces apoptosis in the chemoresistant renal cell carcinoma (RCC). Peroxisome proliferator-activated receptor-? (PPAR?) is a nuclear receptor for 15d-PGJ2, and mediates the cytotoxicity of 15d-PGJ2 in many cancerous cells. However, 15d-PGJ2 induces apoptosis independently of PPAR? in human RCC cell line such as Caki-2. In the present study, we found that 15d-PGJ2 ameliorated the chemoresistance to one of anthracycline antibiotics, doxorubicin, in Caki-2 cells. Doxorubicin alone exhibited weak cytotoxicity at the concentrations effective for other cancer cells such as Hela cells. In addition, it did not activate caspase 3. However, the cytotoxicity of doxorubicin was increased remarkably and accompanied with the caspase- 3 activation in the presence of 15d-PGJ2. Doxorubicin alone damaged plasma membrane, and the combined application of 15d-PGJ2 with doxorubicin increased the membrane permeability slightly. PPAR? was involved in neither the anti-tumor activity nor the synergistic effect of 15d-PGJ2. 15d-PGJ2 induces apoptosis in Caki-2 cells via suppressing the phosphoinositide 3-kinase (PI3K)-Akt pathway. The effect of PI3K inhibitor on the cytotoxicity of doxorubicin was additive, but not synergistic. Although the PI3K inhibitor mimicked the cytotoxicity of 15d-PGJ2, it might not be involved in the synergism between 15d-PGJ2 and doxorubicin. In conclusion, 15d-PGJ2 enhanced the chemosensitivity of doxorubicin via the pathway independent of PPAR? and PI3K.
Project description:Docosahexaenoic acid (DHA) is an omega-3 fatty acid that is considered to have applications in cancer prevention and treatment. The beneficial effects of DHA against cancer metastasis are well established; however, the mechanisms underlying these effects in breast cancer are not clear. Cell invasion is critical for neoplastic metastasis, and involves the degradation of the extracellular matrix by matrix metalloproteinase (MMP)-9. The present study investigated the inhibitory effect of DHA on MMP-9 expression and cell invasion induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) in the MCF-7 breast cancer cell line. DHA inhibited the TPA-induced activation of mitogen-activated protein kinase (MAPK) and the transcription of nuclear factor (NF)-?B, but did not inhibit the transcription of activator protein-1. DHA increased the activity of peroxisome proliferator-activated receptor (PPAR)-?, an effect that was reversed by the application of the PPAR-? antagonist GW9662. In addition, combined treatment with GW9662 and DHA increased NF-?B-related protein expression. These results indicate that DHA regulates MMP-9 expression and cell invasion via modulation of the MAPK signaling pathway and PPAR-?/NF-?B activity. This suggests that DHA could be a potential therapeutic agent for the prevention of breast cancer metastasis.
Project description:15-Deoxy-?-12,14-prostaglandin J2 (15d-PGJ2), a natural peroxisome proliferator-activated receptor-? (PPAR-?) agonist, has been explored in some detail over the last 20 years. By triggering the PPAR-? signalling pathway, it plays many roles and exerts antitumour, anti-inflammatory, antioxidation, antifibrosis, and antiangiogenesis effects. Although many synthetic PPAR-? receptor agonists have been developed, as an endogenous product of PPAR-? receptors, 15d-PGJ2 has beneficial characteristics including rapid expression and the ability to contribute to a natural defence mechanism. In this review, we discuss the latest advances in our knowledge of the biological role of 15d-PGJ2 mediated through PPAR-?. It is important to understand its structure, synthesis, and functional mechanisms to develop preventive agents and limit the progression of associated diseases.
Project description:AIM: Peroxisome proliferator-activated receptor-gamma (PPAR-gamma) has a wide range of biological functions, including anti-inflammation. In this study, we investigated the inhibitory effects of PPAR-gamma on transforming growth factor beta1 (TGF-beta1)-induced interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) expression in renal tubular epithelial cells (HK-2). METHODS: HK-2 cells were pretreated with 15d-PGJ2 or troglitazone (TGL) and then treated with TGF-beta1. Expression of MCP-1 and IL-8 was measured using real-time PCR and ELISA. RESULTS: Treatment with 5 ng/mL TGF-beta1 for 24 h increased both MCP-1 and IL-8 mRNA and protein levels in HK-2 cells. Both 15d-PGJ2 at 2.5 and 5 micromol/L and TGL at 2.5 micromol/L exhibited inhibitory effects on TGF-beta1-induced MCP-1 expression. Additionally, 15d-PGJ2 at 2.5 and 5 micromol/L and TGL at 2.5 micromol/L inhibited TGF-beta1-induced expression of IL-8. CONCLUSION: PPAR-gamma agonists (15d-PGJ2 and TGL) could inhibit the TGF-beta1-induced expression of chemokines in HK-2 cells. Our results suggest that PPAR-gamma agonists have the potential to be used as a treatment regimen to reduce inflammation in renal tubulointerstitial disease.