Ketoprofen S(+) enantiomer inhibits prostaglandin production and cell growth in 3T6 fibroblast cultures

12(S)-hydroxyheptadeca-5Z,8E,10E-trienoic acid (12-HHT) induces cell growth and improves barrier function through BLT2 interaction in intestinal epithelial Caco-2 cell cultures

12(S)-hydroxyheptadeca-5Z,8E,10E-trienoic acid (12-HHT) is an unusual product of the cyclooxygenase pathway that is an endogenous ligand of the low-affinity receptor for leukotriene 4 (LTB₄), BLT2. Recent findings suggested that BLT2 possibly plays an important role in the healing of intestinal lesions and the regulation of barrier function. Here, we studied the role of 12-HHT on intestinal epithelial cell growth and the paracellular permeability of intestinal epithelium using Caco-2 cell cultures as experimental model. Our results demonstrated that 12-HHT stimulates intestinal epithelial Caco-2 cell growth through 12-HHT-BLT2-p38-PKC axis and improves paracellular permeability in differentiated Caco-2 cell cultures through the regulation of tight junction elements such as myosin light chain phosphorylation through 12-HHT-BLT2-p38-PKC-MYPT1 axis. Thus, 12-HHT-BLT2 interaction can be involved in intestinal epithelial cell growth and consequently in the epithelium regeneration/repair processes, together with an interesting improvement on the paracellular permeability. These effects appoint that 12-HHT/BLT2 axis may be a suitable strategy for treating wound healing epithelium and barrier-disrupted intestinal processes.

Chrysin Suppresses HT-29 Cell Death Induced by Diclofenac through Apoptosis and Oxidative Damage

BACKGROUND

Diclofenac (Dic) was shown to increase in reactive oxygen species (ROS) levels thereby resulting oxidative stress and apoptotic cell death in colon cancer. The antioxidants can prevent and repair oxidative damage caused by ROS. The aim of this study was to assess the effect of chrysin (Chr) on Dic-induced toxicity in HT-29 and molecular mechanisms underlying its effect.

METHODS

Cell proliferation and cytotoxicity assays were carried out by WST-1 and LDH leakage assay, apoptotic index was calculated by TUNEL Assay, antioxidant parameters were studied by measurement of ROS, LPO and TAS levels and catalase activity, expression of caspase-3 protein levels were analyzed by immunohistochemical staining, mRNA levels of apoptotic and anti-apoptotic genes were studied by qRT-PCR.

RESULTS

The cellular processes of Dic-triggered cell death was associated with increase in ROS, malondialdehyde levels and lactate dehydrogenase release, decrease in total antioxidant and catalase activity while pretreatment with Chr reversed these effects. The expression level of p53, cas-3, cas-8, Bax and cytochrome c increased in Dic-exposed group while they were reduced by Chr.

CONCLUSION

The use of antioxidant nutritional supplements, and in particular of Chr, may reduce the efficacy of Dic in inducing apoptosis of colon cancer cells.

Chiral Derivatives of Xanthones: Investigation of the Effect of Enantioselectivity on Inhibition of Cyclooxygenases (COX-1 and COX-2) and Binding Interaction with Human Serum Albumin

Searching of new enantiomerically pure chiral derivatives of xanthones (CDXs) with potential pharmacological properties, particularly those with anti-inflammatory activity, has remained an area of interest of our group. Herein, we describe in silico studies and in vitro inhibitory assays of cyclooxygenases (COX-1 and COX-2) for different enantiomeric pairs of CDXs. The evaluation of the inhibitory activities was performed by using the COX Inhibitor Screening Assay Kit. Docking simulations between the small molecules (CDXs; known ligands and decoys) and the enzyme targets were undertaken with AutoDock Vina embedded in PyRx—Virtual Screening Tool software. All the CDXs evaluated exhibited COX-1 and COX-2 inhibition potential as predicted. Considering that the (S)-(−)-enantiomer of the nonsteroidal anti-inflammatory drug ketoprofen preferentially binds to albumin, resulting in lower free plasma concentration than (R)-(+)-enantiomer, protein binding affinity for CDXs was also evaluated by spectrofluorimetry as well as in in silico. For some CDXs enantioselectivity was observed.

Subcutaneous administration of ketoprofen delays Ehrlich solid tumor growth in mice

Ketoprofen, a nonsteroidal anti-inflammatory drug (NSAID) has proven to exert anti-inflammatory, anti-proliferative and anti-angiogenic activities in both neoplastic and non-neoplastic conditions. We investigated the effects of this compound on tumor development in Swiss mice previously inoculated with Ehrlich tumor cells. To carry out this study the solid tumor was obtained from cells of the ascites fluid of Ehrlich tumor re-suspended in physiological saline to give 2.5x106cells in 0.05mL. After tumor inoculation, the animals were separated into two groups (n = 10). The animals treated with ketoprofen 0.1µg/100µL/animal were injected intraperitoneally at intervals of 24h for 10 consecutive days. Animals from the control group received saline. At the end of the experiment the mice were killed and the tumor removed. We analyzed tumor growth, histomorphological and immunohistochemical characteristics for CDC47 (cellular proliferation marker) and for CD31 (blood vessel marker). Animals treated with the ketoprofen 0.1µg/100µL/animal showed lower tumor growth. The treatment did not significantly influence the size of the areas of cancer, inflammation, necrosis and hemorrhage. Moreover, lower rates of tumor cell proliferation were observed in animals treated with ketoprofen compared with the untreated control group. The participation of ketoprofen in controlling tumor malignant cell proliferation would open prospects for its use in clinical and antineoplasic therapy.

Differential cell growth/apoptosis behavior of 13-hydroxyoctadecadienoic acid enantiomers in a colorectal cancer cell line

Cyclooxygenases (COXs) and lipoxygenases (LOXs) are important enzymes that metabolize arachidonic and linoleic acids. Various metabolites generated by the arachidonic acid cascade regulate cell proliferation, apoptosis, differentiation, and senescence. Hydroxyoctadecadienoic acids (HODEs) are synthesized from linoleic acid, giving two enantiomeric forms for each metabolite. The aim was to investigate the effect of 13-HODE enantiomers on nondifferentiated Caco-2 cell growth/apoptosis. Our results indicate that 13(S)-HODE decreases cell growth and DNA synthesis of nondifferentiated Caco-2 cells cultured with 10% fetal bovine serum (FBS). Moreover, 13(S)-HODE showed an apoptotic effect that was reduced in the presence of a specific peroxisome proliferator-activated receptor-γ (PPARγ) antagonist. In addition, we observed that 13(S)-HODE but not 13(R)-HODE is a ligand to PPARγ, confirming the implication of this nuclear receptor in 13(S)-HODE actions. In contrast, 13(R)-HODE increases cell growth and DNA synthesis in the absence of FBS. 13(R)-HODE interaction with BLT receptors activates ERK and CREB signaling pathways, as well as PGE2 synthesis. These results suggest that the proliferative effect of 13(R)-HODE could be due, at least in part, to COX pathway activation. Thus both enantiomers use different receptors and have contrary effects. We also found these differential effects of 9-HODE enantiomers on cell growth/apoptosis. Therefore, the balance between (R)-HODEs and (S)-HODEs in the intestinal epithelium could be important to its cell growth/apoptosis homeostasis.

Role of arachidonic acid metabolites on the control of non-differentiated intestinal epithelial cell growth

Increasingly evidence indicates that enzymes, receptors and metabolites of the arachidonic acid (AA) cascade play a role in intestinal epithelial cell proliferation and colorectal tumorigenesis. However, the information available does not provide a complete picture and contains a number of discrepancies. For this reason it might be appropriate a thorough study into the impacts of the AA cascade on intestinal epithelial cell growth. Our data show that non-differentiated Caco-2 cells cultured with 10% fetal bovine serum (FBS) synthesize appreciable amounts of prostaglandin E2 (PGE2), leukotriene B4 (LTB4) and 5-, 12 and 15-hydroxyeicosatetraenoic acid (HETE) but not LTD4, 20-HETE and epoxyeicosatrienoic acids. We also found that inhibitors of PGE2, LTB4 and 5-, 12-, 15-HETE synthesis as well as receptor antagonists of PGE2 and LTB4 blocked Caco-2 cell growth and DNA synthesis induced by 10% FBS without cytotoxic or apoptotic activity. Interestingly, PGE2, LTB4 and 5-, 12- and 15-HETE at concentrations reached in 10% FBS Caco-2 cultures (1-10nM) were able to induce Caco-2 cell growth and DNA synthesis. This was due to the interaction of PGE2 with EP1 and EP4 receptors and LTB4 and HETEs with BLT1 and BLT2 receptors. Moreover, we provide evidence that PGE2 stimulates several cell signaling pathways such as ERK, P38α, CREB and GSKβ/β-catenin involved in the regulation of Caco-2 growth. Finally, we provide evidence that the mitogenic effects of LTB4 and HETEs can be dependent, at least in part, on PGE2 synthesis.

Epoxyeicosatrienoic acids induce growth inhibition and calpain/caspase-12 dependent apoptosis in PDGF cultured 3T6 fibroblast

Previous studies have demonstrated that arachidonic acid (AA) metabolites released by the cyclooxygenase pathway is involved in serum-induced 3T6 fibroblast cycle progression and proliferation. However, these results also suggest that other AA cascade pathways might be involved. Recently, we also described the role of hydroxyeicosatetraenoic acids, which are produced by cytochrome P450 monooxygenases (CYP), in 3T6 fibroblast growth. AA can be also metabolized by the epoxygenase activity of CYP-producing epoxyeicosatrienoic acids (EETs). Finally, the cytosolic epoxide hydrolases catalyze the hydration of the EETs, transforming them into dihydroxyeicosatetraenoic acids (DHETEs). In this work, we have studied the role of the EETs/DHETEs on 3T6 fibroblasts growth. Our results show that PDGF stimulates 3T6 fibroblast proliferation and [3H]thymidine incorporation, while the addition of 5,6-EET, 8,9-EET, 11,12-EET or 14,15-EET (0.1-1 microM) inhibit these processes. Furthermore, 5,6-DHETE and 11,12-DHETE (0.1-1 microM) also inhibit cell proliferation and DNA synthesis. Interestingly, this growth inhibition was correlated with an induction of apoptosis. Thus, we observed that in the presence of PDGF, EETs or DHETEs (0.1-1 microM) induce phosphatidylserine externalization (as measured by annexin V-binding) and DNA fragmentation (as quantified using a TUNEL assay). Our results show that calpain, as well as caspase-12 and caspase-3, are involved in these events. Therefore, EETs and DHETEs have anti-proliferative and pro-apoptotic effects on PDGF-stimulated 3T6 fibroblasts.

Hydroxyeicosatetraenoic acids released through the cytochrome P-450 pathway regulate 3T6 fibroblast growth

Eicosanoids participate in the regulation of cellular proliferation. Thus, we observed that prostaglandin E(2) interaction with membrane receptors is involved in the control of 3T6 fibroblast growth induced by serum. However, our results suggested that another arachidonic acid pathway might be implicated in these events. Our results show that 3T6 fibroblasts synthesized hydroxyeicosatetraenoic acids (HETEs) such as 12-HETE through the cytochrome P-450 (CYP450) pathway. However, 3T6 fibroblasts did not produce leukotriene B(4) (LTB(4)), and lipoxygenase inhibitors and LT antagonists failed to inhibit 3T6 fibroblast growth induced by FBS. In contrast, we observed that CYP450 inhibitors such as SKF-525A, 17-octadecynoic acid, 1-aminobenzotriazole, and 6-(2-propargyloxyphenyl)hexanoic acid reduced 12(S)-HETE levels, 3T6 fibroblast growth, and DNA synthesis induced by FBS. The impairment of DNA synthesis and 3T6 fibroblast growth induced by SKF-525A were reversed by exogenous addition of HETEs. Moreover, we report that 5-HETE, 12(S)-HETE, and 15(S)-HETE are mitogenic on 3T6 fibroblast in the absence of another growth factor, and this effect was dependent on the activation of the phosphatidylinositol-3-kinase pathway. In conclusion, our results show that HETEs, probably produced by CYP450, are involved in the control of 3T6 fibroblast growth.

Cyclic loading alters biomechanical properties and secretion of PGE2 and NO from tendon explants

BACKGROUND

Tendon overuse injuries are a common occurrence; accounting for a large proportion of occupational and athletic injuries. The concept examined in this study is the role of load-induced intrinsic inflammation to the mechanism of these injuries. This study examined the influence of cyclical loading on the mechanical properties, cell viability, and inflammatory mediators of cultured tendon explants.

METHODS

Chicken digital flexor tendon explants were isolated and separated into no-load (24 h rest), moderate load (0.25-3.0 MPa, 1 Hz, 4 h, 20 h rest), and aggressive load (0.25-12.0 MPa, 1 Hz, 24 h) treatment groups. Tissue loading was carried out with a pneumatic device under load-control. The loading regimens for each explant treatment group started at a uniform time point (day 3 from isolation, t = 0 h). Medium was collected at t = 24 and t = 48 h and analyzed for the inflammatory mediators prostaglandin E(2) and nitric oxide. Viability was evaluated at t = 48 h.

FINDINGS

Biomechanical data revealed a significantly (P < 0.05) lower strength in the aggressively loaded specimens compared to the moderately loaded samples. Prostaglandin E(2) concentrations of aggressively loaded samples showed significantly higher values compared to moderately loaded samples at t = 48 h. Nitric oxide concentrations were greater in the moderately loaded samples relative to the no-load group at t = 24 h. Viability was not found to differ among the groups.

INTERPRETATION

Alterations in cyclical loading of tendon may cause a change in fibroblast-mediated inflammatory mediator production in tendon. This response is of clinical significance as it may have a role in the pathology of tendon overuse injuries.

Role of Ca2+-independent phospholipase A2 and cytochrome P-450 in store-operated calcium entry in 3T6 fibroblasts

Store-operated calcium (SOC) channels and capacitative Ca2+ entry play a key role in cellular functions, but their mechanism of activation remains unclear. Here, we show that thapsigargin induces [3H] arachidonic acid (AA) release, 45Ca2+ influx and a subsequent enhancement of intracellular calcium concentration ([Ca2+]i. Thapsigargin-induced elevation of [Ca2+]i was inhibited by cytochrome P-450 inhibitors and by cytochrome P-450 epoxygenase inhibitor and was reverted by 11,12 EET addition. However, cyclooxygenase and lipoxygenase inhibitors have no effect. Moreover, we observed that four EETs were able to induce 45Ca2+ influx. Finally, we reported that the effect of 11,12 EET on 45Ca2+ influx was sensible to receptor-operated Ca2+ channel blockers (NiCl2, LaCl3) but not to voltage-dependent Ca2+ channel blocker as verapamil. Thus, AA released by Ca2+-independent phospholipase A2 and AA metabolism through cytochrome P-450 pathway may be crucial molecular determinant in thapsigargin activation of SOC channels and store-operated Ca2+ entry pathway in 3T6 fibroblasts. Moreover, EETs, the main cytochrome P-450 epoxygenase metabolites of AA, are involved in thapsigargin-stimulated Ca2+ influx. In summary, our results suggest that EETs are components of calcium influx factor(s).

Different in vitro activity of flurbiprofen and its enantiomers on human articular cartilage

The 2-arylpropionic acid derivatives or 'profens' are an important group of non-steroidal anti-inflammatory drugs that have been used for the symptomatic treatment of various forms of arthritis. These compounds are chiral and the majority of them are still marketed as racemate although it is known that the (S)- form is the principal effective in the cyclooxygenase inhibition. However, recent findings suggest that certain pharmacological effect of 2-arylpropionic acids cannot be attributed exclusively to the (S)-(+) enantiomer. To obtain further insights into the pharmacological effect of profens, the present study investigated the influence of racemic and pure enantiomers of flurbiprofen on the production of nitric oxide and glycosaminoglycans, key molecules involved in cartilage destruction. The culture of human articular cartilage stimulated by interleukin-1beta (IL-1beta), which plays an important role in the degradation of cartilage, has been established, as a profit experimental model, for reproducing the mechanisms involved in the pathophysiology of arthritic diseases. Our results show that mainly (S)-(+)-flurbiprofen decreases, at therapeutically concentrations, the IL-1beta induced cartilage destruction.

Calcium-independent phospholipase A2 through arachidonic acid mobilization is involved in Caco-2 cell growth

Several studies indicate that phospholipase A(2) (PLA(2)) expression and/or activation account for the high levels of arachidonic acid (AA) detected in cancer and, together with the elevated expression of cyclooxygenase-2, lead to cell proliferation and tumor formation. Using Caco-2 cells, a human colorectal carcinoma cell, we studied the role of high-molecular-weight PLA(2)s, cytosolic PLA(2) (cPLA(2)), and calcium-independent PLA(2) (iPLA(2)) in the AA cascade and in cell growth. Treatment with an antisense oligonucleotide against cPLA(2)alpha decreased [(3)H]AA release induced by ionophore A23187 or by a phorbol ester but did not affect the release of [(3)H]AA, [(3)H]thymidine incorporation, or Caco-2 growth induced by fetal calf serum (FCS). However, these parameters were significantly modified by iPLA(2) inhibitors and by an antisense oligonucleotide against iPLA(2)beta. Our results show that iPLA(2) was involved in AA release and the subsequent prostaglandin production induced by serum. Moreover, these data indicate that iPLA(2) may be involved in the signaling pathways involved in the control of Caco-2 proliferation.

Role of EP(1) and EP(4) PGE(2) subtype receptors in serum-induced 3T6 fibroblast cycle progression and proliferation

Recent studies have suggested that prostaglandin E(2) (PGE(2)) subtype receptors (EP) are involved in cellular proliferation and tumor development. We studied the role of EP(1) and EP(4) PGE(2) subtype receptor antagonists AH-6809 and AH-23848B, respectively, in serum-induced 3T6 fibroblast proliferation. This was significantly reduced in a dose-dependent manner (IC(50) approximately 100 and approximately 30 microM, respectively) to an almost complete inhibition, without any cytotoxic effect. However, the effect of each antagonist on 3T6 cell cycle progression clearly differed. Whereas the EP(1) antagonist increased the G(0)/G(1) population, the EP(4) antagonist brought about an accumulation of cells in early S phase. These effects were associated with a decrease in cyclin D and E levels in AH-6809-treated 3T6 cells and lower cyclin A levels in AH-23848B-treated fibroblasts with respect to control cells. The G(0)/G(1) accumulation caused by AH-6809 seems to be intracellular Ca(2+) concentration ([Ca(2+)](i)) dependent, because a 6-h 1 microM thapsigargin treatment allowed G(0)/G(1)-arrested cells to enter S phase. Similarly, treatment with 20 microM forskolin for 6 h allowed S-phase and G(2)/M progression of AH-23848B-treated cells. This study shows that the inhibitory effect of the EP(1) and EP(4) antagonists on serum-induced 3T6 fibroblast growth is due to their effect at various levels of the cell cycle machinery, suggesting that PGE(2) interaction with its different subtype receptors regulates progression through the cell cycle by modulating cAMP and [Ca(2+)](i).

The effect of high molecular phospholipase A2 inhibitors on 3T6 fibroblast proliferation

Recently, we suggested that arachidonic acid and/or its cyclooxygenase pathway metabolites may be involved in regulating 3T6 fibroblast proliferation. In the present study we evaluate the role of high-molecular phospholipase A2 (PLA2) enzymes in the 3T6 fibroblast growth. Our results demonstrate that the cytosolic PLA2 inhibitor, arachidonyl trifluoromethylketone and the cytosolic calcium-independent PLA2 (iPLA2) inhibitor, bromoenol lactone, decrease arachidonic acid release and prostaglandin E2 production in 3T6 fibroblast cultures stimulated by fetal calf serum. These effects were correlated with the impairment of 3T6 fibroblast proliferation and DNA synthesis at the S/G2 boundary, which prolongs the S phase. These data suggest a role of iPLA2 in the control of 3T6 fibroblast growth.

Cyclooxygenase-independent inhibition of smooth muscle cell mitogenesis by ibuprofen

The aryl-propionic acid derivative, ketoprofen, has been shown to inhibit fibroblast growth by a cylooxygenase-dependent mechanism [Sánchez, T., Moreno, J.J., 1999. S(+) enantiomer inhibits prostaglandin production and cell growth in 3T6 fibroblast cultures. Eur. J. Pharmacol. 370, 63-67]. The present study demonstrates that ibuprofen, another aryl-propionic acid derivative, inhibited platelet-derived growth factor-BB (20 ng/ml)-induced mitogenesis of cultured bovine coronary artery smooth muscle cells in a stereo-independent manner. In addition, pretreatment of the cells with indomethacin (3 microM) did not affect the inhibitory effects of ibuprofen enantiomers on smooth muscle cell mitogenesis. Thus, aryl-propionic acid-type cyclooxygenase inhibitors can inhibit cell proliferation by both, cyclooxygenase-dependent and -independent ways.