Inhibition of angiogenesis by nonsteroidal anti-inflammatory drugs: insight into mechanisms and implications for cancer growth and ulcer healing

Gastroprotective activity of violacein isolated from Chromobacterium violaceum on indomethacin-induced gastric lesions in rats: investigation of potential mechanisms of action

Chromobacterium violaceum, Gram-negative bacteria species found in tropical regions of the world, produces a distinct deep violet-colored pigment called violacein. In the present study, we investigated whether violacein can promote a gastroprotective effect and verified the possible mechanisms involved in this action. For this study, an indomethacin-induced gastric ulcer rat model was used. The roles of biomolecules such as MPO, PGE₂, pro- and anti-inflammatory cytokines, growth factors, caspase-3, NO, K⁺ATP channels, and α₂-receptors were investigated. Violacein exhibited significant gastroprotective effect against indomethacin-induced lesions, while pretreatment with L-NAME and glibenclamide (but not with NEM or yohimbine) was able to reverse this action. Pretreatment with violacein also restored cNOS level to normal and led to attenuation of enhanced apoptosis and gastric microvascular permeability. Our results suggest that violacein provides a significant gastroprotective effect in an indomethacin-induced ulcer model through the maintenance of some vital protein molecules, and this effect appears to be mediated, at least in part, by endogenous prostaglandins, NOS, K⁺ATP channel opening, and inhibition of apoptosis and gastric microvascular permeability.

NSAID use and anastomotic leaks following elective colorectal surgery: a matched case-control study

INTRODUCTION

Non-steroidal anti-inflammatory drugs (NSAIDs) decrease postoperative pain and opioid consumption. The objective of the study was to determine if postoperative NSAIDs were associated with anastomotic leaks following elective colorectal surgery.

MATERIALS AND METHODS

We used a matched nested case-control study design. Using a prospectively collected database, we identified all patients having elective colorectal surgery between January 2001 and June 2012. Cases and matched controls were identified based on the occurrence of a postoperative anastomotic leak. The primary and secondary exposure variables were, respectively, use of any NSAID and use of ketorolac specifically. Conditional logistic regression was used to determine the unadjusted and adjusted odds ratio.

RESULTS

A total of 262 patients were included (65.6 % inflammatory bowel disease, 34.4 % cancer). Use of any NSAID was associated with a non-significant increase in anastomotic leaks (odds ratio (OR) 1.81, 95 % confidence interval (CI) 0.98-3.37, p = 0.06). Use of ketorolac was associated with a significant increase in anastomotic leaks (OR 2.09, 95 % CI 1.12-3.89, p = 0.021). There was no significant association between anastomotic leaks and cumulative NSAID dose.

CONCLUSION

These data suggest that there may be an association between NSAIDs and risk of anastomotic leaks after colorectal surgery. Further research is needed to better elucidate this relationship to clarify the implications for patients.

Inhibition of protein phosphatase 2A enhances cytotoxicity and accessibility of chemotherapeutic drugs to hepatocellular carcinomas

Hepatocellular carcinoma (HCC) is one of the most common and therapeutically challenging malignancies worldwide. For patients ineligible for "curative resection" or liver transplantation, chemotherapy is an important minimally effective option. Strategies for chemosensitization are urgently needed. Here, we report that LB-100, a serine/threonine protein phosphatase 2A (PP2A) inhibitor, enhances the cytotoxicity of chemotherapy for HCC in vitro and in vivo. We found that LB-100 significantly enhanced inhibition of HCC by doxorubicin and cisplatin in vitro and in vivo in a PP2A-dependent way, while having little inhibitory activity when used alone. LB-100 promoted vascular endothelial growth factor secretion and vasculogenic mimicry, associated with increased microvessel density and blood perfusion of tumor cell xenografts. LB-100 also enhanced paracellular endothelial permeability to Evans Blue dye and doxorubicin in vivo and in vitro, presumably by altering vascular endothelial-cadherin contact between cells. Changes in permeability and perfusion were accompanied by increased accumulation of doxorubicin in HCC xenografts but not in normal liver tissue. In conclusion, LB-100 enhances chemotherapy by interfering with DNA damage-induced defense mechanisms and by increasing angiogenesis and drug penetration into tumor cells. The induction of angiogenesis and vascular permeability of tumor xenografts by inhibition of PP2A may be a novel approach for enhancing the cytotoxic treatment of HCC and potentially other cancers.

Nuclear adenomatous polyposis coli suppresses colitis-associated tumorigenesis in mice

Mutation of tumor suppressor adenomatous polyposis coli (APC) initiates most colorectal cancers and chronic colitis increases risk. APC is a nucleo-cytoplasmic shuttling protein, best known for antagonizing Wnt signaling by forming a cytoplasmic complex that marks β-catenin for degradation. Using our unique mouse model with compromised nuclear Apc import (Apc(mNLS)), we show that Apc(mNLS/mNLS) mice have increased susceptibility to tumorigenesis induced with azoxymethane (AOM) and dextran sodium sulfate (DSS). The AOM-DSS-induced colon adenoma histopathology, proliferation, apoptosis, stem cell number and β-catenin and Kras mutation spectra were similar in Apc(mNLS/mNLS) and Apc(+/+) mice. However, AOM-DSS-treated Apc(mNLS/mNLS) mice showed more weight loss, more lymphoid follicles and edema, and increased colon shortening than treated Apc(+/+) mice, indicating a colitis predisposition. To test this directly, we induced acute colitis with a 7 day DSS treatment followed by 5 days of recovery. Compared with Apc(+/+) mice, DSS-treated Apc(mNLS/mNLS) mice developed more severe colitis based on clinical grade and histopathology. Apc(mNLS/mNLS) mice also had higher lymphocytic infiltration and reduced expression of stem cell markers, suggesting an increased propensity for chronic inflammation. Moreover, colons from DSS-treated Apc(mNLS/mNLS) mice showed fewer goblet cells and reduced Muc2 expression. Even in untreated Apc(mNLS/mNLS) mice, there were significantly fewer goblet cells in jejuna, and a modest decrease in colonocyte Muc2 expression compared with Apc(+/+) mice. Colonocytes from untreated Apc(mNLS/mNLS) mice also showed increased expression of inflammatory mediators cyclooxygenase-2 (Cox-2) and macrophage inflammatory protein-2 (MIP-2). These findings reveal novel functions for nuclear Apc in goblet cell differentiation and protection against inflammation-induced colon tumorigenesis.

The effect of celecoxib administration on the healing and neovascularization of colonic anastomosis in rats

BACKGROUND

The aim of this experimental study was to investigate whether the perioperative administration of the selective cyclooxygenase-2 inhibitor celecoxib affects the angiogenetic process and the healing of colonic anastomoses.

METHODS

Seventy-two male Wistar rats underwent colonic resection and anastomosis. Celecoxib (10 mg/kg/day-celecoxib group) or placebo (control group) was administered perioperatively. Rats of both groups were sacrificed on either the third or the seventh postoperative day and bursting pressures of the anastomoses were measured. Gelatine-degrading matrix metalloproteinases (MMPs) were identified with gelatine zymography, and proMMP-2 and vascular endothelial growth factor (VEGF) levels from both anastomotic site and tissue adjacent to the anastomosis were evaluated. Histologic evaluation of microvessels was performed by immunohistochemistry using an anti-CD34 monoclonal antibody.

RESULTS

Celecoxib did not significantly decrease anastomotic bursting pressures. Gelatin zymography revealed the presence of MMP-2, proMMP-2, and proMMP-9. MMP concentration was higher at the anastomotic tissue as compared with tissue distant to the anastomosis. Celecoxib resulted in a significant reduction in proMMP-2 levels at the anastomosis at both third and seventh postoperative day. VEGF levels from the anastomotic tissue were also found lower in the celecoxib group. Histological examination showed a celecoxib-induced reduction of newly formed CD34-stained vessels.

CONCLUSIONS

Although the perioperative administration of celecoxib resulted in suppression of angiogenesis in the newly formed anastomoses, bursting pressures remained unaffected and subsequently safety was not compromised.

Enhancement of the physical stability of amorphous indomethacin by mixing it with octaacetylmaltose. inter and intra molecular studies

PURPOSE

To demonstrate a very effective and easy way of stabilization of amorphous indomethacin (IMC) by preparing binary mixtures with octaacetylmaltose (acMAL). In order to understand the origin of increased stability of amorphous system inter- and intramolecular interactions between IMC and acMAL were studied.

METHODS

The amorphous IMC, acMAL and binary mixtures (IMC-acMAL) with different weight ratios were analyzed by using Dielectric Spectroscopy (DS), Differential Scanning Calorimetry (DSC), Raman Spectroscopy, X-ray Diffraction (XRD), Infrared Spectroscopy (FTIR) and Quantitative Structure-Activity Relationship (QSAR).

RESULTS

Our studies have revealed that indomethacin mixed with acetylated saccharide forms homogeneous mixture. Interestingly, even a small amount of modified maltose prevents from recrystallization of amorphous indomethacin. FTIR measurements and QSAR calculations have shown that octaacetylmaltose significantly affects the concentration of indomethacin dimers. Moreover, with increasing the amount of acMAL in the amorphous solid dispersion molecular interactions between matrix and API become more dominant than IMC-IMC ones. Structural investigations with the use of X-ray diffraction technique have demonstrated that binary mixture of indomethacin with acMAL does not recrystallize upon storage at room temperature for more than 1.5 year. Finally, it was shown that acMAL can be used to improve solubility of IMC.

CONCLUSIONS

Acetylated derivative of maltose might be very effective agent to improve physical stability of amorphous indomethacin as well as to enhance its solubility. Intermolecular interactions between modified carbohydrate and IMC are likely to be responsible for increased stability effect in the glassy state.

NFAT2 regulates COX-2 expression and modulates the integrin repertoire in endothelial cells at the crossroads of angiogenesis and inflammation

The mechanisms controlling the switch between the pro-angiogenic and pro-inflammatory states of endothelial cells are still poorly understood. In this paper, we show that: (a) COX-2 expression induced by VEGF-A is NFAT2-dependent; and (b) the integrin profile in endothelial cells induced by the pro-angiogenic VEGF-A is distinct from that brought on by the inflammatory cytokine TNF-α. Two groups of integrin subunits specifically upregulated over time by both cytokines were identified using RT-PCR and Western Immunoblotting. The first group included α4, α5, α6, and β5 subunits that were upregulated by VEGF-A; the second group consisted of αV and β3 induced by TNF-α. Both cytokines significantly enhanced the expression of β1 and modulated α2 mRNA. In contrast to TNF-α, VEGF-A induction of integrin subunits depended on the activation of the calcineurin/NFAT pathway. Both calcineurin inhibitors (cyclosporineA and 11R-VIVIT) and downregulation of NFAT2 with specific siRNA decreased induction of integrin subunits. This process of induction could be increased by upregulation of NFAT2 by pBJ5-NFAT2 transfection. This suggests that NFAT2 mediates VEGF-induced upregulation of integrin subunit synthesis by providing a constant supply of newly synthesized "refreshed" mature integrin receptors, particularly α2β1, α5β1, α4β1, α6β1 and αVβ5, which are involved at different stages of angiogenesis.

Key role of endothelial importin-α in VEGF expression and gastric angiogenesis: novel insight into aging gastropathy

Recent in vivo studies demonstrated that aging gastric mucosa has impaired angiogenesis and reduced expression of vascular endothelial growth factor (VEGF). Angiogenesis is triggered by hypoxia and VEGF gene activation, and the latter requires transport of transcription factor(s) into endothelial cell nuclei. We focused on gastric mucosal endothelial cells (GMEC), which are key targets and effectors of gastric angiogenesis, and determined whether and to what extent importin-α, a nuclear transport protein, regulates VEGF gene activation and gastric angiogenesis and the possible role of importin-α in aging gastropathy. GMEC were isolated from rats 3 and 24 mo of age, young (YGEC) and aging (AGEC), respectively. We examined in these cells 1) in vitro angiogenesis, 2) expression of VEGF and importin-α, 3) nuclear transport of hypoxia-inducible factor (HIF)-1α by importin-α, 4) binding of HIF-1α to the VEGF gene promoter, and 5) effects of importin-α silencing in YGEC and its upregulation in AGEC on angiogenesis and VEGF expression. AGEC exhibited significantly impaired in vitro angiogenesis by fourfold and decreased expression of VEGF, importin-α, and nuclear HIF-1α by 1.4-fold, 1.6-fold, and 2.9-fold, respectively, vs. YGEC. Upregulation of importin-α in AGEC significantly reversed all these abnormalities. In YGEC, knockdown of importins-α1 and -α3 significantly reduced in vitro angiogenesis by 93% and 73% and VEGF expression by 48% and 52%, respectively. The above findings demonstrate that importin-α is a novel and critical regulator of gastric angiogenesis. Its reduced expression in AGEC is the key mechanism for impaired angiogenesis and reduced VEGF.

Quality of healing of gastric ulcers: Natural products beyond acid suppression

Gastric ulcer is a chronic disease featured with unexpected complications, including bleeding, stenosis and perforation, as well as a high incidence of recurrence. Clinical treatments for gastric ulcer have allowed the rapid development of potent anti-ulcer drugs during the last several decades. Gastric ulcer healing is successful with conventional treatments including H₂-receptor antagonists, and proton pump inhibitors (PPIs) have been essential for ulcer healing and prevention of complications. Additionally, Helicobacter pylori eradication therapy is effective in reducing ulcer recurrence and leads to physiological changes in the gastric mucosa which affect the ulcer healing process. However, in spite of these advancements, some patients have suffered from recurrence or intractability in spite of continuous anti-ulcer therapy. A new concept of the quality of ulcer healing (QOUH) was initiated that considers the reconstruction of the mucosal structure and its function for preventing ulcer recurrence. Although several gastroprotection provided these achievements of the QOUH, which PPI or other acid suppressants did not accomplish, we found that gastroprotection that originated from natural products, such as a newer formulation from either Artemisia or S-allyl cysteine from garlic, were very effective in the QOUH, as well as improving clinical symptoms with fewer side effects. In this review, we will introduce the importance of the QOUH in ulcer healing and the achievements from natural products.

Celecoxib: a novel treatment for lung cancer

Lung cancer is by far the leading cause of cancer-related deaths. Overall survival is poor and has not improved substantially over the last 50 years. Therefore, it is clear that novel and more effective treatments are needed to improve the outcome of therapy. Recent attention has been drawn to the role of cyclooxygenase (COX)-2 in the pathogenesis of cancer, and it has been considered as an attractive target for therapeutic and chemopreventive strategies in lung cancer patients. Celecoxib (Celebrex), Pfizer), a selective COX-2 inhibitor and potent anti-inflammatory agent, has been approved for the treatment of osteoarthritis and rheumatoid arthritis. This orally administered agent is generally well tolerated and has almost no gastrointestinal or renal toxicity. Phase II clinical trials suggest that COX-2 inhibition by celecoxib would enhance response to cytotoxic chemotherapy or radiation therapy through interference with cellular proliferation and tumor angiogenic processes, promotion of apoptosis and immune surveillance, or other possible mechanisms. Celecoxib has shown promising antitumor efficacy in lung cancer and a large variety of solid tumors that rely on COX-2-related mechanisms for growth and survival. This article reviews the profile of celecoxib and evidence supporting its role in the therapy of lung cancer.

Topical pluronic F-127 gel application enhances cutaneous wound healing in rats

Pluronic F-127 gel is used as vehicle for various topical applications. In the present study, effects of topical application of pluronic F-127 gel were evaluated in cutaneous wound healing in Wistar rats. Normal saline solution and pluronic F-127 gel (25%) were applied topically on open excision wounds for 14 days. Photography, determination of percentage wound contraction, and collection of granulation tissue were done on days 3, 7, 11 and 14 post-wounding. Topical application of gel (once daily) significantly increased the wound closure on days 11 and 14. The gel application increased the expressions of vascular endothelial growth factor (VEGF) and transforming growth factor-beta1 (TGF-β₁) on days 3 and 7. Histopathologically, more leukocyte infiltration followed by well formed granulation tissue with marked fibroblast proliferation was evident in the gel-treated group, as compared to the saline-treated control group. Immunohistochemistry of CD31 on day 7 revealed significant higher microvessel density in gel-treated wounds. Picrosirius staining demonstrated higher collagen fraction in gel-treated wounds. Thus, from the results, it could be concluded that pluronic F-127 gel has a mild inflammatory nature and enhanced the healing by stimulating expression of VEGF and TGF-β₁.

Growth inhibitory effect of KYKZL-1 on Hep G2 cells via inhibition of AA metabolites and caspase-3 pathway and cell cycle arrest

KYKZL-1, a newly synthesized compound with COX/5-LOX dual inhibition, was subjected to the inhibitory activity test on Hep G2 growth. We found that KYKZL-1 inhibited the growth of Hep G2 cells via inducing apoptosis. Further studies showed that KYKZL-1 activated caspase-3 through cytochrome c release from mitochondria and down regulation of Bcl-2/Bax ratio and reduced the high level of COX-2 and 5-LOX. As shown in its anti-inflammatory effect, KYKZL-1 also exhibited inhibitory effect on the PGE2 and LTB4 production in Hep G2 cells. Accordingly, exogenous addition of PGE2 or LTB4 reversed the decreases in cell viability. In addition, KYKZL-1 caused cell cycle arrest at the S-G2 checkpoint via the activation of p21(CIP1) protein and down-regulation of cyclin A expression. These data indicate that the growth inhibitory effect of KYKZL-1 is associated with inhibition of AA metabolites and caspase-3 pathway and cell cycle arrest. Combined with our previous findings, KYKZL-1 exhibiting COX/5-LOX inhibition may be a promising potential agent not only for inflammation control but also for cancer prevention/therapy with an enhanced gastric safety profile.

MEK inhibition reduces glial scar formation and promotes the recovery of sensorimotor function in rats following spinal cord injury

The aim of this study was to investigate the effect of U0126 on the formation of glial scars following spinal cord injury (SCI) in a rat model. Ninety adult female Sprague-Dawley rats were divided randomly into sham injury (group I), SCI (group II) and U0126 treatment (group III) groups, and functional outcome was observed during the 4 weeks following the injury. The P1 and N1 latencies and P1-N1 amplitudes of somatosensory-evoked potentials (SEPs) were collected one day prior to surgery, on the day of surgery and 14 and 28 days postoperatively. The expression levels of glial fibrillary acidic protein (GFAP) and vimentin (Vim) were assessed 14 and 28 days post-injury. Treatment with U0126 significantly increased locomotor function from the second week until 4 weeks post-SCI. At 14 and 28 days subsequent to the injury, the number of cells that were positive for GFAP expression in the U0126-treated group was significantly reduced and the GFAP-positive cells were observed to be smaller, with a reduced prominence and pale staining. Moreover, the area of glial scarring was smaller compared with that of the SCI controls. Inhibitors of MEK may reduce glial scar formation by suppressing the proliferation of astrocytes, and may improve hindlimb motor function.

Protease-activated receptor 2 signalling pathways: a role in pain processing

INTRODUCTION

Pain is a complex biological phenomenon that includes intricate neurophysiological, behavioural, psychosocial and affective components. Despite decades of pain research, many patients continue suffering from chronic pain that may be refractory to current medical regimens. Accumulating evidence has indicated an important role of protease-activated receptor 2 (PAR2) in the pathogenesis of pain, including inflammation, neuropathic and cancer pain.

AREAS COVERED

In this review, the role of the PAR2 signalling pathway in pain processes, basic mechanism of PAR2 activation and expression of PAR2 in the nervous system is covered. Furthermore, intracellular signalling pathways that are activated by PAR2 are also described.

EXPERT OPINION

The role of PAR2 in pain processing is becoming increasingly clear, and although causal implication remains to be established, PAR2 activation has been observed in several disease model systems. Since PAR2 is activated after nerve injury as well as by trypsin and related serine proteases, and PAR2 plays an important role in pain development and maintenance, exploring PAR2 and its corresponding signalling pathways will provide unfathomable knowledge in understanding the molecular basis of pain. This will also help to identify new targets for pharmacological intervention; however, in the context of potential PAR2-directed therapies, several aspects should be clarified.

Anthropometric, medical history and lifestyle risk factors for myeloproliferative neoplasms in the Iowa Women's Health Study cohort

Classical myeloproliferative neoplasms (MPNs) are composed of essential thrombocythemia (ET), polycythemia vera (PV) and myelofibrosis (MF), the etiology of which is largely unknown. We investigated the role of anthropometric, medical and lifestyle factors with risk of MPN in a prospective cohort of 27,370 women aged 55-69 years at enrollment. After >250,000 person-years of follow-up, 257 cases of MPN were identified (172 ET, 64 PV, 21 MF). Risk factor profiles were mostly unique for the two most common types, ET and PV. ET was associated with energy balance factors including body mass index (RR = 1.52 for >29.3 vs. <23.4 kg/m(2) ; p-trend = 0.042), physical activity (RR = 0.66 for high vs. low; p-trend = 0.04) and adult onset diabetes (RR = 1.82; p = 0.009), while PV was not. PV was associated with current smoking (RR = 2.83; p-trend = 0.016), while ET was not. Regular use of aspirin was associated with lower risk of ET (RR = 0.68; p = 0.017). These results broadly held in multivariate models. Our results suggest distinct etiologies for these MPN subtypes and raise mechanistic hypotheses related to obesity-related inflammatory pathways for ET and smoking-related carcinogenic pathways for PV. Regular aspirin use may lower risk for ET.

The involvement of endoplasmic reticulum stress in the suppression of colorectal tumorigenesis by tolfenamic acid

The nonsteroidal anti-inflammatory drug tolfenamic acid has been shown to suppress cancer cell growth and tumorigenesis in different cancer models. However, the underlying mechanism by which tolfenamic acid exerts its antitumorigenic effect remains unclear. Previous data from our group and others indicate that tolfenamic acid alters expression of apoptosis- and cell-cycle arrest-related genes in colorectal cancer cells. Here, we show that tolfenamic acid markedly reduced the number of polyps and tumor load in APC(min)(/+) mice, accompanied with cyclin D1 downregulation in vitro and in vivo. Mechanistically, tolfenamic acid promotes endoplasmic reticulum (ER) stress, resulting in activation of the unfolded protein response (UPR) signaling pathway, of which PERK-mediated phosphorylation of eukaryotic translation initiation factor 2α (eIF2α) induces the repression of cyclin D1 translation. Moreover, the PERK-eIF2α-ATF4 branch of the UPR pathway plays a role in tolfenamic acid-induced apoptosis in colorectal cancer cells, as silencing ATF4 attenuates tolfenamic acid-induced apoptosis. Taken together, these results suggest ER stress is involved in tolfenamic acid-induced inhibition of colorectal cancer cell growth, which could contribute to antitumorigenesis in a mouse model.

An imbalance between VEGF and endostatin underlies impaired angiogenesis in gastric mucosa of aging rats

Gastric mucosa of aging individuals exhibits increased susceptibility to injury and delayed healing. Our previous studies in young rats showed that healing of mucosal injury depends on and is critically dependent on VEGF and angiogenesis. Since angiogenesis in aging gastric mucosa has not been examined before, in this study we examined the extent to which angiogenesis is impaired in gastric mucosa of aging vs. young rats and determined the underlying mechanisms with a focus on mucosal expression of VEGF (proangiogenic factor) and endostatin (antiangiogenic factor). Aging rats had significantly impaired gastric angiogenesis by ~12-fold, 5-fold, 4-fold, and 3-fold, respectively (vs. young rats; all P < 0.001) at 24, 48, 72, and 120 h following ethanol-induced gastric injury and reduced and delayed healing of mucosal erosions. In gastric mucosa of aging (vs. young) rats at baseline, VEGF expression was significantly reduced, whereas endostatin levels were significantly increased (P < 0.05 and P < 0.01, respectively). In contrast to young rats, gastric mucosal VEGF levels did not increase following ethanol-induced injury in aging rats. MMP-9 enzyme activity was significantly higher in gastric mucosa of aging vs. young rats both at baseline (2.7-fold) and 24 h (3.8-fold) after ethanol injury (both P < 0.001). Since endostatin is generated from collagen XVIII by MMP-9, this finding can explain the mechanism of increased endostatin expression in aging gastric mucosa. The above findings demonstrate that reduced VEGF and increased endostatin result in the impaired angiogenesis and delayed injury healing in gastric mucosa of aging rats.

Aberrant, ectopic expression of VEGF and VEGF receptors 1 and 2 in malignant colonic epithelial cells. Implications for these cells growth via an autocrine mechanism

Vascular endothelial growth factor A (referred to as VEGF) is implicated in colon cancer growth. Currently, the main accepted mechanism by which VEGF promotes colon cancer growth is via the stimulation of angiogenesis, which was originally postulated by late Judah Folkman. However, the cellular source of VEGF in colon cancer tissue; and, the expression of VEGF and its receptors VEGF-R1 and VEGF-R2 in colon cancer cells are not fully known and are subjects of controversy.

MATERIAL AND METHODS

We examined and quantified expression of VEGF, VEGF-R1 and VEGF-R2 in three different human colonic tissue arrays containing sections of adenocarcinoma (n=43) and normal mucosa (n = 41). In human colon cancer cell lines HCT116 and HT29 and normal colon cell lines NCM356 and NCM460, we examined expression of VEGF, VEGF-R1 and VEGF-R2 mRNA and protein, VEGF production and secretion into the culture medium; and, the effect of a potent, selective inhibitor of VEGF receptors, AL-993, on cell proliferation.

RESULTS

Human colorectal cancer specimens had strong expression of VEGF in cancer cells and also expressed VEGF-R1 and VEGF-R2.In vitro studies showed that human colon cancer cell lines, HCT116 and HT29, but not normal colonic cell lines, express VEGF, VEGF-R1 and VEGF-R2 and secrete VEGF into the medium up to a concentration 2000 pg/ml within 48 h. Furthermore, we showed that inhibition of VEGF receptors using a specific VEGF-R inhibitor significantly reduced proliferation (by >50%) of cultured colon cancer cell lines.

CONCLUSIONS

Our findings support the contention that VEGF generated by colon cancer cells stimulates their growth directly through an autocrine mechanism that is independent of its primary function in the induction of angiogenesis.

Cyclooxygenase-2-prostaglandin E2-eicosanoid receptor inflammatory axis: a key player in Kaposi's sarcoma-associated herpes virus associated malignancies

The role of cyclooxygenase-2 (COX-2), its lipid metabolite prostaglandin E2 (PGE2), and Eicosanoid (EP) receptors (EP; 1-4) underlying the proinflammatory mechanistic aspects of Burkitt's lymphoma, nasopharyngeal carcinoma, cervical cancer, prostate cancer, colon cancer, and Kaposi's sarcoma (KS) is an active area of investigation. The tumorigenic potential of COX-2 and PGE2 through EP receptors forms the mechanistic context underlying the chemotherapeutic potential of nonsteroidal anti-inflammatory drugs (NSAIDs). Although role of the COX-2 is described in several viral associated malignancies, the biological significance of the COX-2/PGE2/EP receptor inflammatory axis is extensively studied only in Kaposi's sarcoma-associated herpes virus (KSHV/HHV-8) associated malignancies such as KS, a multifocal endothelial cell tumor and primary effusion lymphoma (PEL), a B cell-proliferative disorder. The purpose of this review is to summarize the salient findings delineating the molecular mechanisms downstream of COX-2 involving PGE2 secretion and its autocrine and paracrine interactions with EP receptors (EP1-4), COX-2/PGE2/EP receptor signaling regulating KSHV pathogenesis and latency. KSHV infection induces COX-2, PGE2 secretion, and EP receptor activation. The resulting signal cascades modulate the expression of KSHV latency genes (latency associated nuclear antigen-1 [LANA-1] and viral-Fas (TNFRSF6)-associated via death domain like interferon converting enzyme-like- inhibitory protein [vFLIP]). vFLIP was also shown to be crucial for the maintenance of COX-2 activation. The mutually interdependent interactions between viral proteins (LANA-1/vFLIP) and COX-2/PGE2/EP receptors was shown to play key roles in the biological mechanisms involved in KS and PEL pathogenesis such as blockage of apoptosis, cell cycle regulation, transformation, proliferation, angiogenesis, adhesion, invasion, and immune-suppression. Understanding the COX-2/PGE2/EP axis is very important to develop new safer and specific therapeutic modalities for KS and PEL. In addition to COX-2 being a therapeutic target, EP receptors represent ideal targets for pharmacologic agents as PGE2 analogues and their blockers/antagonists possess antineoplastic activity, without the reported gastrointestinal and cardiovascular toxicity observed with few a NSAIDs.

The proapoptotic effect of traditional and novel nonsteroidal anti-inflammatory drugs in mammalian and yeast cells

Nonsteroidal anti-inflammatory drugs (NSAIDs) have long been used to treat pain, fever, and inflammation. However, mounting evidence shows that NSAIDs, such as aspirin, have very promising antineoplastic properties. The chemopreventive, antiproliferative behaviour of NSAIDs has been associated with both their inactivation of cyclooxygenases (COX) and their ability to induce apoptosis via pathways that are largely COX-independent. In this review, the various proapoptotic pathways induced by traditional and novel NSAIDs such as phospho-NSAIDs, hydrogen sulfide-releasing NSAIDs and nitric oxide-releasing NSAIDs in mammalian cell lines are discussed, as well as the proapoptotic effects of NSAIDs on budding yeast which retains the hallmarks of mammalian apoptosis. The significance of these mechanisms in terms of the role of NSAIDs in effective cancer prevention is considered.

Has the time come for metronomics in low-income and middle-income countries?

In 2008, 72% of cancer deaths occurred in low-income and middle-income countries, where, although there is a lower incidence of cancer than in high-income countries, survival rates are also low. Many patients are sent home to die, and an even larger number of patients do not have access to treatment facilities. New constraint-adapted therapeutic strategies are therefore urgently needed. Metronomic chemotherapy--the chronic administration of chemotherapy at low, minimally toxic doses on a frequent schedule of administration, with no prolonged drug-free breaks--has recently emerged as a potential strategy to control advanced or refractory cancer and represents an alternative for patients with cancer living in developing countries. This low-cost, well-tolerated, and easy to access strategy is an attractive therapeutic option in resource-limited countries. Moreover, combined with drug repositioning, additional anticancer effects can be achieved, ultimately resulting in improved cancer control while maintaining minimum cost of treatment. In this Personal View, we will briefly review the rationale behind the combination of metronomic chemotherapy and drug repositioning-an approach we term metronomics. We assess the clinical experience obtained with this kind of anticancer treatment and describe potential new developments in countries with limited resources. We also highlight the need for adapted clinical study endpoints and innovative models of collaboration between for-profit and non-profit organisations, to address the growing problem of cancer in resource-limited countries.

Influence of levamisole and other angiogenesis inhibitors on angiogenesis and endothelial cell morphology in vitro

Angiogenesis, the formation of new blood vessels from existing vessels is required for many physiological processes and for growth of solid tumors. Initiated by hypoxia, angiogenesis involves binding of angiogenic factors to endothelial cell (EC) receptors and activation of cellular signaling, differentiation, migration, proliferation, interconnection and canalization of ECs, remodeling of the extracellular matrix and stabilization of newly formed vessels. Experimentally, these processes can be studied by several in vitro and in vivo assays focusing on different steps in the process. In vitro, ECs form networks of capillary-like tubes when propagated for three days in coculture with fibroblasts. The tube formation is dependent on vascular endothelial growth factor (VEGF) and omission of VEGF from the culture medium results in the formation of clusters of undifferentiated ECs. Addition of angiogenesis inhibitors to the coculture system disrupts endothelial network formation and influences EC morphology in two distinct ways. Treatment with antibodies to VEGF, soluble VEGF receptor, the VEGF receptor tyrosine kinase inhibitor SU5614, protein tyrosine phosphatase inhibitor (PTPI) IV or levamisole results in the formation of EC clusters of variable size. This cluster morphology is a result of inhibited EC differentiation and levamisole can be inferred to influence and block VEGF signaling. Treatment with platelet factor 4, thrombospondin, rapamycin, suramin, TNP-470, salubrinal, PTPI I, PTPI II, clodronate, NSC87877 or non-steriodal anti-inflammatory drugs (NSAIDs) results in the formation of short cords of ECs, which suggests that these inhibitors have an influence on later steps in the angiogenic process, such as EC proliferation and migration. A humanized antibody to VEGF is one of a few angiogenesis inhibitors used clinically for treatment of cancer. Levamisole is approved for clinical treatment of cancer and is interesting with respect to anti-angiogenic activity in vivo since it inhibits ECs in vitro with a morphology resembling that obtained with antibodies to VEGF.

Concurrent targeting of eicosanoid receptor 1/eicosanoid receptor 4 receptors and COX-2 induces synergistic apoptosis in Kaposi's sarcoma-associated herpesvirus and Epstein-Barr virus associated non-Hodgkin lymphoma cell lines

The effective antitumorigenic potential of nonsteroidal anti-inflammatory drugs (NSAIDs) and eicosonoid (EP; EP1-4) receptor antagonists prompted us to test their efficacy in Kaposi's sarcoma-associated herpesvirus (KSHV) and Epstein-Barr virus (EBV) related lymphomas. Our study demonstrated that (1) EP1-4 receptor protein levels vary among the various non-Hodgkin's lymphoma (NHL) cell lines tested (BCBL-1:KSHV+/EBV-;BC-3: KSHV+/EBV-; Akata/EBV+: KSHV-/EBV+; and JSC-1 cells: KSHV+/EBV + cells); (2) 5.0 μM of EP1 antagonist (SC-51322) had a significant antiproliferative effect on BCBL-1, BC-3, Akata/EBV+, and JSC-1 cells; (3) 50.0 μM of EP2 antagonist (AH6809) was required to induce a significant antiproliferative effect on BCBL-1, Akata/EBV+, and JSC-1 cells; (4) 5.0 μM of EP4 antagonist (GW 627368X) had a significant antiproliferative effect on BC-3, Akata/EBV+, and JSC-1 cells; (5) COX-2 selective inhibitor celecoxib (5.0 μM) had significant antiproliferative effects on BCBL-1, BC-3, Akata/EBV+, and JSC-1 cells; and (6) a combination of 1.0 μM each of celecoxib, SC-51322 and GW 627368X could potentiate the proapoptotic properties of celecoxib or vice-versa. Overall, our studies identified the synergistic antiproliferative effect of NSAIDs and EP receptor blockers on KSHV and EBV related B cell malignancies.

Xylitol inhibits in vitro and in vivo angiogenesis by suppressing the NF-κB and Akt signaling pathways

Angiogenesis is an important process involved in tumor growth and metastasis. Many studies have investigated the use of natural compounds such as angiogenic inhibitors. Xylitol is a 5-carbon sugar alcohol and is an artificial sweetener that has been used in chewing gums to prevent tooth decay. Xylitol has been also known to inhibit inflammatory cytokine expression induced by lipopolysaccharide (LPS). Since angiogenesis and inflammation share a common signaling pathway, we investigated the role of xylitol in angiogenesis. Xylitol inhibited the migration, invasion and tube formation of human umbilical vein endothelial cells (HUVECs). Xylitol also inhibited in vivo angiogenesis in a mouse Matrigel plug assay. Furthermore, mRNA expression of vascular endothelial growth factor (VEGF), VEGFR-II (KDR), basic fibroblast growth factor (bFGF), bFGFR-II, matrix metalloproteinase-2 (MMP-2) and MMP-9 of HUVECs decreased following treatment with xylitol. These anti-angiogenic effects of xylitol are exerted through inhibition of NF-κB and Akt activation. Taken together, these results suggest that xylitol acts as a beneficial angiogenesis inhibitor.

Surgery and stress promote cancer metastasis: new outlooks on perioperative mediating mechanisms and immune involvement

Surgery for the removal of a primary tumor presents an opportunity to eradicate cancer or arrest its progression, but is also believed to promote the outbreak of pre-existing micrometastases and the initiation of new metastases. These deleterious effects of surgery are mediated through various mechanisms, including psychological and physiological neuroendocrine and paracrine stress responses elicited by surgery. In this review we (i) describe the many risk factors that arise during the perioperative period, acting synergistically to make this short timeframe critical for determining long-term cancer recurrence, (ii) present newly identified potent immunocyte populations that can destroy autologous tumor cells that were traditionally considered immune-resistant, thus invigorating the notion of immune-surveillance against cancer metastasis, (iii) describe in vivo evidence in cancer patients that support a role for anti-cancer immunity, (iv) indicate neuroendocrine and paracrine mediating mechanisms of stress- and surgery-induced promotion of cancer progression, focusing on the prominent role of catecholamines and prostaglandins through their impact on anti-cancer immunity, and through direct effects on the malignant tissue and its surrounding, (v) discuss the impact of different anesthetic approaches and other intra-operative procedures on immunity and cancer progression, and (vi) suggest prophylactic measures against the immunosuppressive and cancer promoting effects of surgery.

Effect of systemic celecoxib on human meningioma after intracranial transplantation into nude mice

BACKGROUND

Meningiomas are mostly benign, but they may have a notorious tendency to recur when total resection is not possible. Systemic chemotherapeutical treatment has been largely disappointing. The treatment of meningiomas with the cyclooxygenase-2 (COX-2) inhibitor celecoxib showed inhibitory-growth effects in vitro and in vivo after subcutaneous transplantation into mouse. So far, celecoxib has never been tested in an orthotopic model of meningioma. In this work, we tested the effects of celecoxib on the growth of human benign meningiomas after transplantation into the prefrontal cortex of nude mice after confirming the inhibitory in vitro effect on these cells.

METHODS

Primary cell cultures were stereotactically implanted into mice and were treated with 0, 750, or 1,500 ppm celecoxib for 3 months. The mice were then killed and blood was analyzed for celecoxib concentration. The mice brains were histologically processed for measurement of tumor volume, COX-2 expression, proliferation index (PI), intratumoral microvessel density (iMVD), and vascular endothelial growth factor (VEGF) expression.

RESULTS

Treatment with celecoxib had no effect on tumor volume, despite the fact that we found a dose-dependent inhibitory effect on cell cultures and there was a sufficiently high celecoxib concentration in blood plasma and brain tissue. Additionally, celecoxib had neither an effect on COX-2 and VEGF expression nor on the PI and iMVD.

CONCLUSIONS

Our findings suggest that celecoxib may not be effective on meningioma growth in clinical settings. In general, these results may indicate that the effect of treatment on brain tumors should not only be tested in a heterotopic environment but also in the orthotopic location of these tumors.

Synthesis and antiangiogenic activity of N-alkylated levamisole derivatives

Inhibition of angiogenesis is a promising addition to current cancer treatment strategies. Neutralization of vascular endothelial growth factor by monoclonal antibodies is clinically effective but may cause side effects due to thrombosis. Low molecular weight angiogenesis inhibitors are currently less effective than antibody treatment and are also associated with serious side effects. The discovery of new chemotypes with efficient antiangiogenic activity is therefore of pertinent interest. (S)-levamisole hydrochloride, an anthelminthic drug approved for human use and with a known clinical profile, was recently shown to be an inhibitor of angiogenesis in vitro and exhibited tumor growth inhibition in mice. Here we describe the synthesis and in vitro evaluation of a series of N-alkylated analogues of levamisole with the aim of characterizing structure-activity relationships with regard to inhibition of angiogenesis. N-methyllevamisole and p-bromolevamisole proved more effective than the parent compound, (S)-levamisole hydrochloride, with respect to inhibition of angiogenesis and induction of undifferentiated cluster morphology in human umbilical vein endothelial cells grown in co-culture with normal human dermal fibroblasts. Interestingly, the cluster morphology caused by N-methyllevamisole was different than the clusters observed for levamisole, and a third "cord-like" morphology resembling that of the known drug suramin was observed for an aniline-containing derivative. New chemotypes exhibiting antiangiogenic effects in vitro are thus described, and further investigation of their underlying mechanism of action is warranted.

Interrelationship and expression profiling of cyclooxygenase and angiogenic factors in Indian patients with multiple myeloma

Multiple myeloma (MM) is classically illustrated by a desynchronized cytokine system with rise in inflammatory cytokines. There are recent reports which emphasized the potential role of angiogenesis in the development of MM. Role of cyclooxygenase 2 (COX-2) is well documented in the pathogenesis of solid tumors, but little is known about its occurrence and function in hematologic neoplasms. Involvement of neoangiogenesis is reported in the progression of MM, and angiopoietins probably contribute to this progression by enhancing neovascularization. Circulatory and mRNA levels of angiogenic factors and cyclooxygenase were determined in 125 subjects (75 MM patients and 50 healthy controls) by using enzyme-linked immunosorbent assay and quantitative PCR. We observed significant increase for angiogenic factors (Ang-1, Ang-2, hepatocyte growth factor, and vascular endothelial growth factor) and cyclooxygenase at circulatory level, as well as at mRNA level, as compared to healthy controls except insignificant increase for Ang-1 at circulatory level. We have also observed the significant positive correlation of all angiogenic factors with cyclooxygenase. The strong association found between angiogenic factors and COX-2 in this study may lead to the development of combination therapeutic strategy to treat MM. Therefore, targeting COX-2 by using its effective inhibitors demonstrating antiangiogenic and antitumor effects could be used as a new therapeutic approach for treatment of MM.

Betaine inhibits in vitro and in vivo angiogenesis through suppression of the NF-κB and Akt signaling pathways

Angiogenesis is defined as the formation of new blood vessels form existing vessels surrounding a tumor. The process of angiogenesis is an important step for tumor growth and metastasis, as is inflammation. Thus, angiogenesis inhibitors that suppress inflammation have been studied as an anticancer treatment. Recently, many research groups have investigated the anti-angiogenic activity of natural compounds since some have been demonstrated to have anticancer properties. Among many natural compounds, we focused on betaine, which is known to suppress inflammation. Betaine, trimethylglycine (TMG), was first discovered in the juice of sugar beets and was later shown to be present in wheat, shellfish and spinach. In Southeast Asia, betaine is used in traditional oriental medicine for the treatment of hepatic disorders. Here, we report the anti-angiogenic action of betaine. Betaine inhibited in vitro angiogenic cascade, tube formation, migration and invasion of human umbilical vein endothelial cells (HUVECs). Betaine also inhibited in vivo angiogenesis in the mouse Matrigel plug assay. The mRNA expression levels of basic fibroblast growth factor (bFGF), matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) in HUVECs were decreased by betaine treatment. In addition, betaine suppressed NF-κB and Akt activation.

Predictive role of plasma vascular endothelial growth factor for the effect of celecoxib in advanced non-small cell lung cancer treated with chemotherapy

AIM OF THE STUDY

The primary purpose of this study is to investigate if pretreatment plasma levels of vascular endothelial growth factor (VEGF) are predictive of the effect of celecoxib on survival in advanced non-small cell lung cancer (NSCLC) treated with palliative chemotherapy. A secondary objective is to describe the course of plasma VEGF levels during and after treatment with cytotoxic chemotherapy combined with celecoxib or placebo.

METHODS

In a previously published double-blind multicenter phase III trial, 316 patients with NSCLC stage IIIB or IV and World Health Organisation (WHO) performance status 0-2 were randomised to receive celecoxib 400mg b.i.d. or placebo in combination with two-drug platinum-based chemotherapy. Chemotherapy cycle length was three weeks and planned duration of chemotherapy was four cycles. Celecoxib was given for a maximum of one year but was stopped earlier in case of disease progression or prohibitive toxicity. In a subset of patients, plasma VEGF levels were examined at onset of treatment and at 6, 12 and 20 weeks.

RESULTS

VEGF levels at start of treatment were obtained in 107 patients at four study sites. The median value was 70 pg/ml. Mean values declined during the first 12 weeks and then increased at 20 weeks. A subpopulation treatment effect pattern plot (STEPP) analysis showed an inverse relationship between initial plasma VEGF and the impact of celecoxib on survival with zero effect at 200 pg/ml. The effect on survival by celecoxib in the whole subset of patients was positive (hazard ratio (HR)=0.64 [confidence interval (CI) 0.43-0.95], p=0.028).

CONCLUSION

Low pretreatment plasma levels of VEGF appear to be predictive of a positive effect of celecoxib on survival.

Gallic Acid Enriched Fraction of Phyllanthus emblica Potentiates Indomethacin-Induced Gastric Ulcer Healing via e-NOS-Dependent Pathway

The healing activity of gallic acid enriched ethanolic extract (GAE) of Phyllanthus emblica fruits (amla) against the indomethacin-induced gastric ulceration in mice was investigated. The activity was correlated with the ability of GAE to alter the cyclooxygenase- (COX-) dependent healing pathways. Histology of the stomach tissues revealed maximum ulceration on the 3rd day after indomethacin (18 mg/kg, single dose) administration that was associated with significant increase in inflammatory factors, namely, mucosal myeloperoxidase (MPO) activity and inducible nitric oxide synthase (i-NOS) expression. Proangiogenic parameters such as the levels of prostaglandin (PG) E₂, vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), von Willebrand Factor VIII, and endothelial NOS (e-NOS) were downregulated by indomethacin. Treatment with GAE (5 mg/kg/day) and omeprazole (3 mg/kg/day) for 3 days led to effective healing of the acute ulceration, while GAE could reverse the indomethacin-induced proinflammatory changes of the designated biochemical parameters. The ulcer healing activity of GAE was, however, compromised by coadministration of the nonspecific NOS inhibitor, N-nitro-L-arginine methyl ester (L-NAME), but not the i-NOS-specific inhibitor, L-N6-(1-iminoethyl) lysine hydrochloride (L-NIL). Taken together, these results suggested that the GAE treatment accelerates ulcer healing by inducing PGE₂ synthesis and augmenting e-NOS/i-NOS ratio.

COX inhibitors Indomethacin and Sulindac derivatives as antiproliferative agents: synthesis, biological evaluation, and mechanism investigation

Cyclooxygenase (COX) inhibitors Indomethacin and its structural analogs Sulindac exhibit cell growth inhibition and apoptosis inducing activities in various cancer cell lines via COX independent mechanisms. In this study, the molecular structures of Indomethacin and Sulindac were used as starting scaffolds to design novel analogs and their effects on the proliferation of human cancer cells were evaluated. Compared to Indomethacin and Sulindac inhibiting cancer cell proliferation with IC(50)s of more than 1 mM, the derivatives displayed significantly increased activities. Especially, one of the Indomethacin analogs inhibited the growth of a series of cancer cell lines with IC(50)s around 0.5 μM-3 μM. Mechanistic investigation revealed that the new analog was in fact a tubulin inhibitor, although the parental compound Indomethacin did not show any tubulin inhibitory activity. Tubulin polymerization assay indicated this compound inhibited tubulin assembly at high concentrations, but promoted this process at low concentrations which is a very unique mechanism. The binding mode of this compound in tubulin was predicted using the molecular docking simulation.

Igf2bp1 is required for full induction of Ptgs2 mRNA in colonic mesenchymal stem cells in mice

BACKGROUND & AIMS

Prostaglandin-endoperoxide synthase (Ptgs)2 is an enzyme involved in prostaglandin production during the response to mucosal damage. Its expression is regulated, in part, by messenger RNA (mRNA)-binding proteins that control the stability of Ptgs2 mRNA. We used a precise system of colonic injury and repair to identify Ptgs2 mRNA-binding proteins.

METHODS

We used endoscopy-guided mucosal excision to create focal injury sites in colons of mice. Wound beds from wild-type, Ptgs2(-/-), Ptgs2(+/-), and Myd88(-/-) mice were analyzed at 2-day intervals after injury for aspects of repair and Ptgs2 expression. We used cultured colonic mesenchymal stem cells (cMSCs) that express Ptgs2 to identify and analyze molecules that regulate Ptgs2 expression.

RESULTS

Ptgs2(-/-) mice had defects in wound repair, validating the biopsy technique as a system to study the regulation of Ptgs2. Ptgs2(+/-) mice had similar defects in wound healing, so full induction of Ptgs2 is required for wound repair. In wild-type mice, levels of Ptgs2 mRNA increased significantly in the wound bed 2 and 4 days after injury; the highest levels of Ptgs2 were observed in cMSCs. In a functional short hairpin RNA knockdown screen, we identified Igf2bp1, a VICKZ (Vg1 RNA binding protein, Insulin-like growth factor II mRNA binding protein 1, Coding region determinant-binding protein, KH domain containing protein overexpressed in cancer, and Zipcode-binding protein-1) mRNA-binding protein, as a regulator of Ptgs2 expression in cMSCs. Igf2bp1 also interacted physically with Ptgs2 mRNA. Igf2bp1 expression was induced exclusively in wound-bed cMSCs, and full induction of Ptgs2 and Igf2bp1 during repair required Myd88.

CONCLUSIONS

We identified Igf2bp1 as a regulator of Ptgs2 mRNA in mice. Igf2bp1 is required for full induction of Ptgs2 mRNA in cMSCs.

Ellagic acid facilitates indomethacin-induced gastric ulcer healing via COX-2 up-regulation

The mechanism of indomethacin-induced gastric ulcer healing by ellagic acid (EA) in experimental mice model is described in our study. Ulcer index (UI) and myeloperoxidase (MPO) activity of the stomach tissues showed maximum ulceration on the third day after indomethacin (18 mg/kg, single dose) administration. Preliminary observation of UI and MPO activity suggests that EA possesses ulcer-healing activity. Other anti-ulcer parameters such as the levels of prostaglandin E(2), cyclooxygenase (COX) 1 and 2 enzymes, anti-inflammatory cytokines [interleukin (IL)-4 and -5], pro-angiogenic factors, e.g. vascular endothelial growth factor, hepatocyte growth factor (HGF), and endothelial growth factor (EGF) were down-regulated by indomethacin. EA (7 mg/kg/day) treatment for 3 days shifted the indomethacin-induced pro-inflammatory biochemical parameters to the healing side. These activities were correlated with the ability of EA to alter the COX-2-dependent healing pathways. The ulcer-healing activity of EA was, however, compromised by pre-administration of the specific COX-2 inhibitor, celecoxib, and NS-398. Taken together, these results suggested that the EA treatment accelerates ulcer healing by inducing IL-4, EGF/HGF levels and enhances COX-2 expression.

Gene expression profile of coronary artery cells treated with nonsteroidal anti-inflammatory drugs reveals off-target effects

Nonsteroidal anti-inflammatory drugs (NSAIDs) have come under scrutiny because of the gastrointestinal, renal, and cardiovascular toxicity associated with prolonged use of these drugs. The purpose of this study was to identify molecular targets for NSAIDs related to cellular toxicity with a view to optimize drug efficacy in the clinic. Coronary artery smooth muscle cells and endothelial cells were treated with low (clinically achievable) and high (typically used in preclinical studies) concentrations of celecoxib, NS398, and ibuprofen for 24 hours. NSAIDs-induced gene expression changes were evaluated by microarray analysis and validated by real-time reverse-transcription polymerase chain reaction and western blotting. The functional significance of differentially expressed genes was evaluated by Ingenuity Pathway Analysis. At high concentrations, NSAIDs altered the expression of genes regulating cell proliferation and cell death. NSAIDs also altered genes associated with cardiovascular functions including inflammation, thrombosis, fibrinolysis, coronary artery disease, and hypertension. The gene expression was most impacted by ibuprofen, celecoxib, and NS398, in that order. This study revealed that NSAIDs altered expression of an array of genes associated with cardiovascular events and emphasizes the potential for fingerprinting drugs in preclinical studies to assess the potential drug toxicity and to optimize the drug efficacy in clinical settings.

Risk of anastomotic leakage with non-steroidal anti-inflammatory drugs in colorectal surgery

BACKGROUND

With the implementation of multimodal analgesia regimens in fast-track surgery programmes, non-steroidal anti-inflammatory drugs (NSAIDs) are being prescribed routinely. However, doubts have been raised concerning the safety of NSAIDs in terms of anastomotic healing.

METHODS

Data on patients who had undergone primary colorectal anastomosis at two teaching hospitals between January 2008 and December 2010 were analysed retrospectively. Exact use of NSAIDs was recorded. Rates of anastomotic leakage were compared between groups and corrected for known risk factors in both univariable and multivariable analyses.

RESULTS

A total of 795 patients were divided into four groups according to NSAID use: no NSAIDs (471 patients), use of non-selective NSAIDs (201), use of selective cyclo-oxygenase (COX) 2 inhibitors (79), and use of both selective and non-selective NSAIDs (44). The overall leak rate was 9.9 per cent (10.0 per cent for right colonic, 8.7 per cent for left colonic and 12.4 per cent for rectal anastomoses). Known risk factors such as smoking and use of steroids were not significantly associated with anastomotic leakage. Stapled anastomosis was identified as an independent predictor of leakage in multivariable analysis (odds ratio (OR) 2.22, 95 per cent confidence interval 1.30 to 3.80; P = 0.003). Patients on NSAIDs had higher anastomotic leakage rates than those not on NSAIDs (13.2 versus 7.6 per cent; OR 1.84, 1.13 to 2.98; P = 0.010). This effect was mainly due to non-selective NSAIDs (14.5 per cent; OR 2.13, 1.24 to 3.65; P = 0.006), not selective COX-2 inhibitors (9 per cent; OR 1.16, 0.49 to 2.75; P = 0.741). The overall mortality rate was 4.2 per cent, with no significant difference between groups (P = 0.438).

CONCLUSION

Non-selective NSAIDs may be associated with anastomotic leakage.

Clinical pharmacology of nonsteroidal anti-inflammatory drugs in dogs

OBJECTIVES

To discuss the clinical pharmacology of currently licensed veterinary NSAIDs and to review gastrointestinal and renal adverse effects as well as drug-drug interactions that have been reported with these drugs. To review the use of NSAIDs in the peri-operative setting and their use in patients with osteoarthritis. To further review the reported effects of NSAIDs on canine articular cartilage and liver as well as the clinical relevance of a washout period.

DATABASES USED

PubMed, CAB abstracts and Google Scholar using dog, dogs, nonsteroidal anti-inflammatory drugs and NSAID(s) as keywords.

CONCLUSIONS

A good understanding of the mechanisms by which NSAIDs elicit their analgesic effect is essential in order to minimize adverse effects and drug-drug interactions. Cyclooxygenase (COX) is present in at least two active isoforms in the body and is the primary pharmacologic target of NSAIDs. Inhibition of COX is associated with the analgesic effects of NSAIDs. COX is present in the gastrointestinal tract and kidneys, along with other areas of the body, and is also the likely reason for many adverse effects including gastrointestinal and renal adverse effects. The newer veterinary approved NSAIDs have a lower frequency of gastrointestinal adverse effects in dogs compared to drugs such as aspirin, ketoprofen and flunixin, which may be due to differential effects on the COX isoforms. There are currently no published reports demonstrating that the newer NSAIDs are associated with fewer renal or hepatic adverse effects in dogs. NSAIDs remain the cornerstone of oral therapy for osteoarthritis unless contraindicated by intolerance, concurrent therapies or underlying medical conditions. NSAIDs are also effective and frequently used for the management of post-operative pain.

Anti-inflammatory effect of pelubiprofen, 2-[4-(oxocyclohexylidenemethyl)-phenyl]propionic acid, mediated by dual suppression of COX activity and LPS-induced inflammatory gene expression via NF-κB inactivation

Pelubiprofen is a non-steroidal anti-inflammatory drugs (NSAIDs) that is related both structurally and pharmacologically to ibuprofen. Anti-inflammatory properties of ibuprofen are due to its ability to both decrease prostaglandin synthesis by inhibiting the activities of cyclooxygenases (COXs) and IκB kinase-β (IKK-β). However, the exact mechanisms that accounts for the anti-inflammatory effects of pelubiprofen are not reported. In this study, we investigated the molecular mechanisms how pelubiprofen modulates the inflammatory mediators in LPS-induced macrophages and carrageenan-induced acute inflammatory rat model. Pelubiprofen potently diminished PGE(2) productions through inhibition of COX enzyme activity (IC(50) values for COX-1 and COX-2 are 10.66 ± 0.99 and 2.88 ± 1.01 µM, respectively), but also reduced the expressions of COX-2, inducible nitric oxide (iNOS), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and IL-6 at transcriptional level in LPS-induced RAW 264.7 cells. In addition, pelubiprofen attenuated the LPS-induced transcription activity and the DNA binding activity of NF-κB, which was accompanied by a parallel reduction of degradation and phosphorylation of inhibitory kappa B-α (IκB-α) and consequently by decreased nuclear translocation of NF-κB. Furthermore, pelubipofen inhibited the LPS-induced phosphorylation of IKK-β and transforming growth factor-β activated kinase-1 (TAK1). In acute inflammatory rat model, pretreatment with pelubiprofen inhibited carrageenan-induce edema, neutrophil migration, PGE(2) production, and p65, a subunit of NF-κB, nuclear translocation in inflamed paw. Taken together, our data indicated that pelubiprofen is involved in the dual inhibition of COX activity and TAK1-IKK-NF-κB pathway, revealing molecular basis for the anti-inflammatory properties of pelubiprofen.

Molecular mechanism of indomethacin-induced gastropathy

The probable cross talk among large numbers of inflammatory and angiogenic parameters in indomethacin (IND)-induced gastropathy and the associated signaling mechanism were studied in a mouse model. A single dose of IND (18 mg/kg, po) produced robust gastric ulceration in mice without any mortality, which peaked on the third day, but started healing from the fifth day onward. The ulceration was associated with increased myeloperoxidase activity and expression of proinflammatory (TNF-α, adhesion molecules, COX-2) and antiangiogenic (endostatin) parameters. The levels of proangiogenic factors such as COX-1, prostaglandin E, VEGF, and von Willebrand factor VIII were downregulated by IND. Our results revealed that although the maximal and minimal levels of these parameters were attained sequentially at different time points, TNF-α upregulation was the primary event to initiate and induce gastric ulceration. IND also activated NF-κB and all the MAP kinases, but only the inhibitors of TNF-α, NF-κB, and JNK MAP kinase could abrogate the IND-induced damages. Further TNF-α inhibition also reduced the IND-mediated activation of NF-κB and JNK MAP kinase. All this evidence strongly suggests that mitigation of TNF-α may offer a potential solution to IND-mediated gastropathy.

MIF produced by bone marrow-derived macrophages contributes to teratoma progression after embryonic stem cell transplantation

Although stem cell therapy holds promise as a potential treatment in a number of diseases, the tumorigenicity of embryonic stem cells (ESC) and induced pluripotent stem cells remains a major obstacle. In vitro predifferentiation of ESCs can help prevent the risk of teratoma formation, yet proliferating neural progenitors can generate tumors, especially in the presence of immunosuppressive therapy. In this study, we investigated the effects of the microenvironment on stem cell growth and teratoma development using undifferentiated ESCs. Syngeneic ESC transplantation triggered an inflammatory response that involved the recruitment of bone marrow (BM)-derived macrophages. These macrophages differentiated into an M2 or angiogenic phenotype that expressed multiple angiogenic growth factors and proteinases, such as macrophage migration inhibitory factor (MIF), VEGF, and matrix metalloproteinase 9, creating a microenvironment that supported the initiation of teratoma development. Genetic deletion of MIF from the host but not from ESCs specifically reduced angiogenesis and teratoma growth, and MIF inhibition effectively reduced teratoma development after ESC transplantation. Together, our findings show that syngeneic ESC transplantation provokes an inflammatory response that involves the rapid recruitment and activation of BM-derived macrophages, which may be a crucial driving force in the initiation and progression of teratomas.

Curcumin heals indomethacin-induced gastric ulceration by stimulation of angiogenesis and restitution of collagen fibers via VEGF and MMP-2 mediated signaling

AIM

We examined the molecular mechanism of curcumin in a preventive and therapeutic model of indomethacin-induced gastric ulceration with regard to angiogenic processes.

RESULTS

Disrupted blood vessels, reduced collagen matrices, and significant (60%) injury to mucosal cells were observed during ulceration. In addition, ulcerated tissues exhibited decreased matrix metalloproteinase (MMP)-2 and vascular endothelial growth factor (VEGF) expression in blood vessels. Interestingly, curcumin blocked ulceration by induction of collagenization and angiogenesis in gastric tissues via upregulation of MMP-2, membrane type (MT) 1-MMP, VEGF, and transforming growth factor (TGF)-β at protein and messenger ribonucleic acid (mRNA) levels. To examine the angiogenic properties of curcumin, we employed a chorioallantoic membrane model and Matrigel assay. During healing, curcumin promoted collagenization and angiogenesis as well as enhanced MMP-2 activity via positive MT1-MMP regulation and negative tissue inhibitor of metalloproteinase-2 regulation.

INNOVATION

Our study demonstrates that curcumin-mediated healing is associated with increased MMP-2, TGF-β, and VEGF expression and that it plays a pivotal role as an angiogenic modulator by stimulating vascular sprout formation and collagen fiber restoration in ulcerated tissues.

CONCLUSION

We conclude that curcumin remodels gastric tissues by restoring the collagen architecture and accelerating angiogenesis.