Myricetin inhibits matrix metalloproteinase 2 protein expression and enzyme activity in colorectal carcinoma cells

Colorectal carcinoma is a leading cause of human mortality due to its high metastatic ability. Because the activation of matrix metalloproteinases (MMP) is a key factor in the metastatic process, agents with the ability to inhibit MMP activity have potential in the treatment of colorectal carcinoma. In the present study, among 36 flavonoids examined, myricetin was found to be the most potent inhibitor of MMP-2 enzyme activity in COLO 205 cells (IC50 = 7.82 micromol/L). Myricetin inhibition of MMP-2 enzyme activity was also found in the human colorectal carcinoma cell lines COLO 320HSR, COLO 320DM, HT 29, and COLO 205-X (IC50 = 11.18, 11.56, 13.25, and 23.51 micromol/L, respectively). In contrast, no inhibitory effect of MMP-2 protein expression or enzyme activity was observed in myricitrin (myricetin-3-rhamnoside)-treated cells. In 12-O-tetradecanoylphorbol-13-acetate (TPA)-stimulated COLO 205 cells, an increase in MMP-2 protein expression and enzyme activity, as well as of protein kinase C (PKC) alpha protein translocation, extracellular signal-regulated kinase (ERK) 1/2 protein phosphorylation, and c-Jun protein expression was observed. ERK inhibitor (PD98059) and PKC inhibitors (GF-109203X and H-7), but not p38 inhibitor (SB203580) or c-jun-NH2-kinase inhibitor (SP600125), significantly inhibited TPA-induced MMP-2 protein expression, with reduced ERK phosphorylation and c-Jun protein expression. Addition of myricetin but not myricitrin suppressed TPA-induced MMP-2 protein expression in COLO 205 cells by blocking the TPA-induced events, including translocation of PKCalpha from cytosol to membrane, phosphorylation of ERK1/2 protein, and induction of c-Jun protein expression. Addition of PD98059 or GF-109203X significantly enhanced the inhibitory effect of myricetin on MMP-2 enzyme activity induced by TPA. Furthermore, myricetin, but not myricitrin, suppressed TPA-induced invasion of COLO 205 cells in an in vitro invasion assay using Engelbreth-Holm-Swarm sarcoma tumor extract Matrigel-coated Transwells. Results of the present study indicate that myricetin significantly blocked both endogenous and TPA-induced MMP-2 enzyme activity by inhibiting its protein expression and enzyme activity. The blockade involved suppression of PKC translocation, ERK phosphorylation, and c-Jun protein expression.     

Heme oxygenase-1 inhibits the proliferation of pancreatic stellate cells by repression of the extracellular signal-regulated kinase1/2 pathway

Activation of pancreatic stellate cells (PSCs) is the key process in the development of pancreatic fibrosis, a common feature of chronic pancreatitis and pancreatic cancer. In recent studies, curcumin has been shown to inhibit PSC proliferation via an extracellular signal-regulated kinase (ERK)1/2-dependent mechanism. In addition, curcumin is a potent inducer of the cytoprotective enzyme heme oxygenase-1 (HO-1) in other cell types. Therefore, the aims of this study were to 1) characterize the effect of curcumin on HO-1 gene expression in PSCs, 2) explore whether HO-1 induction contributes to the inhibitory effect of curcumin on PSC proliferation, and 3) clarify the involvement of the mitogen-activated protein kinase (MAPK) family in this context. Cultured rat PSCs were incubated with curcumin and assessed for HO-1 up-regulation by Northern blot analysis, immunoblotting, and activity assays. The effect of HO-1 on platelet-derived growth factor (PDGF)-induced PSC proliferation and MAPK activation was determined by immunoblotting, cell proliferation assays, and cell count analyses. Curcumin induced HO-1 gene expression in PSCs in a time- and dose-dependent manner and inhibited PDGF-mediated ERK1/2 phosphorylation and PSC proliferation. These effects were blocked by treatment of PSCs with tin protoporphyrin IX, an HO inhibitor, or transfection of HO-1 small interfering RNA. Our data provide evidence that HO-1 induction contributes to the inhibitory effect of curcumin on PSC proliferation. Therefore, therapeutic up-regulation of HO-1 could represent a mode for inhibition of PSC proliferation and thus may provide a novel strategy in the prevention of pancreatic fibrosis.     

Differential activation of heme oxygenase-1 by chalcones and rosolic acid in endothelial cells

The induction of heme oxygenase-1 (HO-1) is widely recognized as an effective cellular strategy to counteract a variety of stressful events. We have shown that curcumin and caffeic acid phenethyl ester, two naturally occurring phytochemicals that possess antioxidant, anti-inflammatory, and anticarcinogenic activities, induce HO-1 in many cell types. This suggests that stimulation of HO-1 could partly underlie the beneficial effects exerted by these plant-derived constituents. Here we examined the ability of additional plant constituents to up-regulate heme oxygenase activity and HO-1 in aortic endothelial cells. Incubation of endothelial cells with a series of polyphenolic chalcones (5-50 microM) resulted in increased heme oxygenase activity; interestingly, the chemical structure dictated the pattern of heme oxygenase induction, which was unique to each particular compound employed. We also found that rosolic acid, a constituent isolated from the rhizome of Plantago asiatica L. dramatically increased HO-1 in a concentration- and time-dependent manner. Severe cytotoxicity was observed after prolonged exposure (24 or 48 h) of cells to curcumin and caffeic acid phenethyl ester, whereas 2'-hydroxychalcone and rosolic acid did not affect cell viability. By using different mitogen-activated protein kinase inhibitors, we determined that the extracellular signal-regulated kinase, p38, and c-Jun NH(2)-terminal protein kinase pathways play only a minor role in the induction of HO-1 by rosolic acid and 2'-hydroxychalcone. On the other hand, increased intra- and extracellular thiols markedly reduced the rise in heme oxygenase activity elicited by rosolic acid. Thus, this study identified novel plant constituents that highly induce HO-1 in endothelial cells and investigated some of the mechanisms involved in this effect.     

Heme oxygenase-1 alleviates mouse hepatic failure through suppression of adaptive immune responses

Heme oxygenase-1 (HO-1) has protective effects on liver damage induced by noxious stimuli. The mechanism of action of HO-1 is not well understood. In the present study, we investigate the effect of HO-1 in a model of fulminant hepatic failure induced by Propionibacterium acnes and lipopolysaccharide (LPS). The expression of HO-1 mRNA and protein in the liver was increased after repeated administration of the HO-1 inducer cobalt protoporphyrin IX. We found that HO-1 protected mice from acute liver damage induced by P. acnes/LPS and prolonged survival. On the contrary, administration of the HO-1 inhibitor zinc protoporphyrin IX increased liver damage induced by P. acnes/LPS. Subsequently, to investigate the underlying mechanisms of HO-1 in the acute liver injury model, we primed mice with P. acnes only. We found that the expression of HO-1 mRNA and protein in dendritic cells (DCs) was increased after the administration of cobalt protoporphyrin IX. HO-1 decreased the mature markers major histocompatibility complex II and CD80 on liver DCs. The expression of CCR7, CCL2, and CCL22 mRNA, which are expressed by mature DCs, was also reduced. These liver DCs could not efficiently stimulate CD4+ T cell activation and proliferation. Consequently, HO-1 inhibited the activation, proliferation, and T helper 1 polarization of liver-infiltrating CD4+ T cells and reduced the production of serum alanine aminotransferase and proinflammatory cytokines such as interferon-γ and tumor necrosis factor-α. Taken together, our data suggest that HO-1 alleviates P. acnes/LPS-induced fulminant hepatic failure, probably by inhibiting DC-induced adaptive responses.     

人参皂甙Rg3对乳腺癌细胞(MCF-7)表达金属蛋白酶2、9(MMP-2,MMP-9)的影响

目的为了研究人参皂甙Rg3对乳腺癌细胞(MCF-7)细胞分泌的基质金属蛋白酶(MMP-2,MMP-9)表达的影响。方法免疫组化法测定了用人参皂甙Rg3前后MCF-7细胞基质金属蛋白酶(MMP-2,MMP-9)的表达。结果分析表明人参皂甙Rg3能减少MCF-7细胞基质金属蛋白酶(MMP-2,MMP-9)表达。结论人参皂甙Rg3能抑制基质金属蛋白酶MMP-2、MMP-9的分泌。     

Heme oxygenase-1 and carbon monoxide suppress autoimmune neuroinflammation

Heme oxygenase-1 (HO-1, encoded by HMOX1) dampens inflammatory reactions via the catabolism of heme into CO, Fe, and biliverdin. We report that expression of HO-1 dictates the pathologic outcome of experimental autoimmune encephalomyelitis (EAE), a model of multiple sclerosis (MS). Induction of EAE in Hmox1(-/- )C57BL/6 mice led to enhanced CNS demyelination, paralysis, and mortality, as compared with Hmox1(+/+) mice. Induction of HO-1 by cobalt protoporphyrin IX (CoPPIX) administration after EAE onset reversed paralysis in C57BL/6 and SJL/J mice and disease relapse in SJL/J mice. These effects were not observed using zinc protoporphyrin IX, which does not induce HO-1. CoPPIX protection was abrogated in Hmox1(-/-) C57BL/6 mice, indicating that CoPPIX acts via HO-1 to suppress EAE progression. The protective effect of HO-1 was associated with inhibition of MHC class II expression by APCs and inhibition of Th and CD8 T cell accumulation, proliferation, and effector function within the CNS. Exogenous CO mimicked these effects, suggesting that CO contributes to the protective action of HO-1. In conclusion, HO-1 or exposure to its end product CO counters autoimmune neuroinflammation and thus might be used therapeutically to treat MS.     

Intracellular uptake and behavior of two types zinc protoporphyrin (ZnPP) micelles, SMA-ZnPP and PEG-ZnPP as anticancer agents; unique intracellular disintegration of SMA micelles

SMA-ZnPP and PEG-ZnPP are micellar drugs, encapsulating zinc protoporphyrin IX (ZnPP) with styrene maleic acid copolymer (SMA) and covalent conjugate of ZnPP with polyethylene glycol (PEG) respectively. Their intracellular uptake rate and subcellular localization were investigated. We found SMA-ZnPP showed higher and more efficient (about 2.5 times) intracellular uptake rate than PEG-ZnPP, although both SMA-ZnPP and PEG-ZnPP micelles were localized at endoplasmic reticulum (ER) and inhibited the target enzyme heme oxygenase 1 (HO-1) similarly. Both micellar ZnPP were taken up into the tumor cells by endocytosis. Furthermore SMA-ZnPP and PEG-ZnPP were examined for their drug releasing mechanisms. Liberation of ZnPP from the SMA micelle appears to depend on cellular amphiphilic components such as lecithin, while that for PEG-ZnPP depends on hydrolytic cleavage. These results indicate that these micelle formulations make water insoluble ZnPP to water soluble practical anticancer agents.     

血红素氧合酶1修饰骨髓间充质干细胞多点注射梗死灶周围对梗死后心肌结构重塑的影响

背景：研究表明血红素氧合酶1的过表达有抗炎症反应的作用,将血红素氧合酶1修饰的骨髓间充质干细胞（HO-1-BMSCs）移植入梗死心脏周围是否可调节基质金属蛋白酶/组织金属蛋白酶抑制剂的比例而明显改善梗死心肌重构呢？目的：观察血红素氧合酶1修饰的骨髓间充质干细胞移植对心肌梗死后心肌胶原的调节及心肌重塑的逆转作用。方法：利用血红素氧合酶1腺病毒转染体外培养扩增的骨髓间充质干细胞。结扎大鼠左前降支动脉制造心肌梗死模型,1h后,分别将HO-1-BMSCs、BMSCs多点注射到大鼠心脏梗死区四周,对照组注射等量磷酸盐缓冲液。结果与结论：Adv-hHO-1转染BMSCs后获稳定表达;hHO-1-mRNA仅在HO-1-BMSCs移植组表达;与对照组相比,HO-1-BMSCs移植组基质金属蛋白酶2/9的表达显著减少（P〈0.05）,Null-BMSCs组基质金属蛋白酶2/9的表达虽然减少,但差异无显著性意义（P〉0.05）;与对照组相比,细胞移植组金属蛋白酶组织抑制剂2/3的表达显著增加,尤以HO-1-BMSCs组明显（P〈0.05）;但金属蛋白酶组织抑制剂1无明显变化（P〉0.05）。金属蛋白酶组织抑制剂2/基质金属蛋白酶2和金属蛋白酶组织抑制剂3/基质金属蛋白酶9的比例在细胞移植的心脏中明显上升。与对照组比较,细胞移植组心室中的胶原蛋白沉积减少,心室腔内径显著缩小。结果表明血红素氧合酶1修饰的骨髓间充质干细胞移植可使基质金属蛋白酶/组织金属蛋白酶抑制剂的比例正常化,并逆转心肌细胞外基质的重构。     

Carbon monoxide generated by heme oxygenase 1 suppresses endothelial cell apoptosis

Heme oxygenase 1 (HO-1) inhibits apoptosis by regulating cellular prooxidant iron. We now show that there is an additional mechanism by which HO-1 inhibits apoptosis, namely by generating the gaseous molecule carbon monoxide (CO). Overexpression of HO-1, or induction of HO-1 expression by heme, protects endothelial cells (ECs) from apoptosis. When HO-1 enzymatic activity is blocked by tin protoporphyrin (SnPPIX) or the action of CO is inhibited by hemoglobin (Hb), HO-1 no longer prevents EC apoptosis while these reagents do not affect the antiapoptotic action of bcl-2. Exposure of ECs to exogenous CO, under inhibition of HO-1 activity by SnPPIX, substitutes HO-1 in preventing EC apoptosis. The mechanism of action of HO-1/CO is dependent on the activation of the p38 mitogen-activated protein kinase (MAPK) signaling transduction pathway. Expression of HO-1 or exposure of ECs to exogenous CO enhanced p38 MAPK activation by TNF-alpha. Specific inhibition of p38 MAPK activation by the pyridinyl imidazol SB203580 or through overexpression of a p38 MAPK dominant negative mutant abrogated the antiapoptotic effect of HO-1. Taken together, these data demonstrate that the antiapoptotic effect of HO-1 in ECs is mediated by CO and more specifically via the activation of p38 MAPK by CO.     

Puerarin protects human umbilical vein endothelial cells against high glucose-induced apoptosis by upregulating heme oxygenase-1 and inhibiting calpain activation

The aim of this study was to investigate whether puerarin protects against high glucose (HG)-induced apoptosis by suppressing calpain activation in human umbilical vein endothelial cells (HUVECs). HUVECs were exposed to normal glucose (NG) (5.5 mm) or HG (33 mm) for 48 h; then, apoptosis and caspase-3 activity were determined. The expression of heme oxygenase-1 (HO-1) mRNA was evaluated by RT-PCR analysis. The activation of calpain and HO activity were also assessed. Compared with the NG group, exposure of HUVECs to HG for 48 h resulted in significant increases in calpain and caspase-3 activity as well as apoptosis, which were prevented by co-incubation with puerarin (1-100 μm) in a concentration-dependent manner. HO-1 mRNA expression and HO activity were decreased in HUVECs treated with HG for 48 h. Compared with the group exposed to HG alone, co-incubation of HUVECs with puerarin and HG induced increases in HO-1 mRNA expression and HO activity. The HO-1 inhibitor protoporphyrin IX zinc (II) abolished the inhibitory effect of puerarin on HG-induced calpain and caspase-3 activation, as well as apoptosis. The data show that puerarin protects against HG-induced endothelial cell apoptosis by a mechanism involving upregulation of HO-1 expression and inhibition of calpain activity.     

Differential effects of heme oxygenase isoforms on heme mediation of endothelial intracellular adhesion molecule 1 expression.

Heme oxygenase (HO), by catabolizing heme to bile pigments, down-regulates cellular hemoprotein, hemoglobin, and heme; the latter generates pro-oxidant products, including free radicals. Two HO isozymes, the products of distinct genes, have been described; HO-1 is the inducible isoform, whereas HO-2 is suggested to be constitutively expressed. We studied the inducing effect of several metal compounds (CoCl(2), stannic mesoporphyrin, and heme) on HO activity. Additionally, we studied HO-1 expression in experimental models of adhesion molecule expression produced by heme in endothelial cells, and the relationship of HO-1 expression to the induced adhesion molecules. Flow cytometry analysis showed that heme induces intracellular adhesion molecule 1 (ICAM-1) expression in a concentration (10-100 microM)- and time (1-24 h)-dependent fashion in human umbilical vein endothelial cells. Pretreatment with stannic mesoporphyrin, an inhibitor of HO activity, caused a 2-fold increase in heme-induced ICAM-1 expression. In contrast, HO induction by CoCl(2) decreased heme-induced ICAM-1 expression by 33%. To examine the contribution of HO-1 and HO-2 to endothelial HO activity, specific antisense oligonucleotides (ODNs) of each isoform were tested for their specificity to inhibit HO activity in cells exposed to heme. Endothelial cells exposed to heme elicited increased HO activity, which was prevented (70%) by HO-1 antisense ODNs. HO-2 antisense ODN inhibited heme-induced HO activity by 21%. Addition of HO-1 antisense ODNs prevented heme degradation and resulted in elevation of microsomal heme. Western blot analysis showed that HO-1 antisense ODNs selectively inhibited HO-1 protein and failed to inhibit HO-2 protein. Incubation of endothelial cells with HO-1 antisense enhanced heme-dependent increase of ICAM-1. In contrast, addition of HO-2 antisense to endothelial cells failed to increase adhesion molecules. The role of glutathione, an important antioxidant, was examined on heme-induced ICAM-1 expression. Endothelial cells pretreated with a glutathione precursor, N-acetylcysteine, or glutathione ester, showed a decrease in heme-induced ICAM-1 expression of 37 and 44%, respectively, suggesting that the mechanism of ICAM-1 induction by heme may be partly dependent on the levels of antioxidant. It is possible that amelioration of the heme-induced oxidative stress and expression of ICAM-I is due, in part, to the induction of HO-1 activity. Regulation of HO activity in this manner may have clinical applications.     

The heme oxygenase inducer hemin protects against cardiac dysfunction and ventricular fibrillation in ischaemic/reperfused rat hearts: role of connexin 43

Cardiac expression of cytoprotective gene heme oxygenase-1 (HO-1) is modulated by ischaemia and reperfusion (I/R). We therefore hypothesized that pretreatment with hemin, an inductor of HO-1, would precondition the heart against post-ischaemic dysfunction and ventricular fibrillation (VF). Male Wistar rats were given either hemin or HO enzyme inhibitor zinc protoporphyrin IX (ZnPP IX). Isolated hearts were subjected to 30 min global ischaemia followed by 120 min of reperfusion or were aerobically perfused in a time-matched non-ischaemic protocol. Control animals received no pretreatment. Compared to non-perfused controls, pretreatment with hemin increased HO-1 mRNA 13-fold (p<0.001) and HO-1 protein 3.5-fold (p相似文献   

Induction of heme oxygenase-1 inhibits the monocyte transmigration induced by mildly oxidized LDL.

Heme catabolic processes produce the antioxidants biliverdin and bilirubin, as well as the potent prooxidant free iron. Since these products have opposing effects on oxidative stress, it is not clear whether heme catabolism promotes or inhibits inflammatory processes, including atherosclerotic lesion formation. Heme oxygenase (HO) catalyzes the rate-limiting step of heme catabolism. We used cocultures of human aortic endothelial cells and smooth muscle cells to examine the possible role of HO in early atherosclerosis. Heme oxygenase-1 (HO-1), the inducible isoform of HO, was highly induced by mildly oxidized LDL, and augmented induction was observed with hemin pretreatment. This augmented HO-1 induction resulted in the reduction of monocyte chemotaxis in response to LDL oxidation. Conversely, inhibition of HO by a specific inhibitor, Sn-protoporphyrin IX, enhanced chemotaxis. Furthermore, pretreatment with biliverdin or bilirubin, the products of HO, reduced chemotaxis. Oxidized phospholipids in the mildly oxidized LDL appear to be responsible for HO-1 induction, since oxidized but not native arachidonic acid-containing phospholipids also induced HO-1. These results suggest that HO-1 induced by mildly oxidized LDL may protect against the induction of inflammatory responses in artery wall cells through the production of the antioxidants biliverdin and bilirubin.     

Heme oxygenase type 2 plays a role in formalin-induced nociception

Although much attention has been focused in recent years on nitric oxide synthase (NOS) as an enzyme intimately involved in many types of nociceptive signaling, the enzyme heme oxygenase (HO) has received little attention. Yet, HO produces gaseous second messenger molecule CO which, like NO, has proven to be an important neurotransmitter in the CNS. In these studies we provide detailed evidence that HO activity is critical to formalin-induced licking behavior in mice. The HO inhibitor tin protoporphyrin (Sn-P) dose-dependently reduced formalin-stimulated licking behavior in both phases of the formalin assay. This apparent analgesic effect was unlikely due to the non-specific effects of this agent as Sn-P did not alter rotarod performance, and the blood-brain barrier impermeant HO inhibitor zinc protoporphyrin (Zn-P) had little effect on licking times. We also hypothesized that heme oxygenase type 2 (HO-2) was the specific isoform of HO involved in nociception. Mice with a targeted disruption of the HO-2 gene were found to have greatly reduced licking times. Furthermore, Sn-P did not further reduce licking times when administered to HO-2 knockout animals. Taken together our evidence indicates that HO plays an important role in nociceptive signaling related to inflammatory-type pain, and that HO-2 is the isozyme mediating this nociception.     

Heme oxygenase 1 mediates the immunomodulatory and antiapoptotic effects of interleukin 13 gene therapy in vivo and in vitro

This study analyzes mechanisms by which interleukin 13 (IL-13) affects "infectious tolerance" in rat recipients of cardiac allografts, with emphasis on interactions between intragraft Ad-IL-13 gene transfer and systemic infusion of regulatory cells. Although exogenous viral IL-13 was modestly effective on its own, adjunctive Ad-IL-13 gene therapy and adoptive transfer of suboptimal dose of regulatory T cells exerted synergistic effects, as evidenced by long-term cardiac allograft survival in test recipients. Local IL-13 induction (determined by enzyme-linked immunosorbent assay and immunohistology) diminished intragraft apoptosis, and upregulated antiapoptotic A20 and antioxidant heme oxygenase 1 (HO-1). Ad-IL-13 plus regulatory cells synergistically diminished the frequency of cells positive by TUNEL (TdT [terminal deoxynucleotidyltransferase]-mediated dUTP nick-end labeling) assay, and enhanced cytoprotective gene expression. These findings correlated with in vitro studies in which Ad-IL-13 decreased tumor necrosis factor alpha (TNF-alpha)-mediated cytotoxicity, conferred resistance to apoptosis, and increased HO-1/A20 expression in human umbilical vein endothelial cell (HUVEC) cultures. However, inhibition of HO-1 after treatment with tin protoporphyrin reversed the immunomodulatory/antiapoptotic effects of Ad-IL-13 both in vivo (infectious transplantation tolerance), and in vitro (HUVECs). Thus, by decreasing apoptosis/TNF-alpha-mediated cytotoxicity, and by facilitating induction of antiapoptotic/antioxidant molecules in HUVECs, this study documents the cytoprotective function of Ad-IL-13 in vitro, and points toward in vivo synergy between Ad-IL-13 and regulatory cells in the infectious transplantation tolerance pathway. Results of HO-1 neutralization studies suggest that HO-1 represents one of the putative IL-13 downstream effectors.