leukotriene-b4 and Carcinoma--Squamous-Cell

Alcohol drinking is a known risk factor for oral cancer in humans. However, previous animal studies on the promoting effect of ethanol on oral carcinogenesis were inconclusive. It is necessary to develop an animal model with which the molecular mechanism of ethanol-related oral carcinogenesis may be elucidated to develop effective prevention strategies. In this study, mice were first treated with 4-nitroquinoline-1-oxide (4NQO, 100 μg/mL in drinking water) for 8 weeks and then given water or ethanol (8%) as the sole drink for another 16 weeks. During the experiment, 8% ethanol was well tolerated by mice. The incidence of squamous cell carcinoma (SCC) increased from 20% (8/41) to 43% (17/40; P < 0.05). Expression of 5-lipoxygenase (5-Lox) and cyclooxygenase 2 (Cox-2) was increased in dysplasia and SCC of 4NQO-treated tongues and further enhanced by ethanol. Using this mouse model, we further showed that fewer cancers were induced in Alox5(-/-) mice, as were cell proliferation, inflammation, and angiogenesis in the tongue, as compared with Alox5(+/+) mice. Interestingly, Cox-2 expression was induced by ethanol in knockout mice, whereas 5-Lox and leukotriene A4 hydrolase (LTA4H) expression and leukotriene B4 (LTB4) biosynthesis were dramatically reduced. Moreover, ethanol enhanced expression and nuclear localization of 5-Lox and stimulated LTB4 biosynthesis in human tongue SCC cells (SCC-15 and SCC-4) in vitro. In conclusion, this study clearly showed that ethanol promoted 4NQO-induced oral carcinogenesis, at least in part, through further activation of the 5-Lox pathway of arachidonic acid metabolism.

Topics: 4-Nitroquinoline-1-oxide; Animals; Anti-Infective Agents, Local; Arachidonate 5-Lipoxygenase; Arachidonic Acid; Blotting, Western; Carcinogens; Carcinoma, Squamous Cell; Cells, Cultured; Cocarcinogenesis; Cyclooxygenase 2; Drinking Water; Epoxide Hydrolases; Ethanol; Humans; Immunoenzyme Techniques; Leukotriene B4; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Mouth Neoplasms; Signal Transduction; Tongue Neoplasms

To evaluate the chemopreventive effects of boswellic acid and curcumin on 7,12-dimethyl benzanthracene(DMBA)-induced oral carcinogenesis in the hamster cheek pouch model.. Male Syrian golden hamsters (6 - 8 weeks old, 80 - 130 g in weight) were randomly divided into seven groups, with group A serving as the untreated negative control. The left cheek pouch of the remaining hamsters was topically treated with 0.5% DMBA in mineral oil three times a week for 6 weeks. They were then randomized to six groups with group B serving as a positive control and receiving no further treatment. Groups C-G were treated topically with 5, 10 mg/L boswellic acid, 5, 10 µmol/L curcumin, or the combination of 5 mg/L boswellic acid and 5 µmol/L curcumin three times per week for 18 weeks. The animals were injected with bromodeoxyuridine intraperitoneally at 50 mg/kg 2 h prior to killing. At the 25 th week all the hamsters were sacrificed and cheek pouch tissue was harvested. One half of the tissue was snap frozen in liquid nitrogen for analysis of arachidonic acid metabolites, and the other half was fixed in 10% phosphate-buffered saline(PBS)-buffered formalin for histopathological examination.. Six-weeks of DMBA followed by 18-weeks of topical application of boswellic acid and curcumin, both boswellic acid (5, 10 mg/L) and curcumin (5, 10 µmol/L) significantly inhibited the incidence from 93.8% to 73.9% (P > 0.05), numbers from 2.19 ± 0.98 to 1.13 ± 0.81 (P < 0.01) and size of visible tumors. Microscopically the incidence of squamous cell carcinoma and BrdU index were also significantly suppressed by boswellic acid and curcumin.. Both boswellic acid and curcumin were effective in preventing oral carcinogenesis in DMBA-induced hamster cheek pouch model.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Animals; Antineoplastic Agents; Bromodeoxyuridine; Carcinogenesis; Carcinogens; Carcinoma, Squamous Cell; Cheek; Cricetinae; Curcumin; Hyperplasia; Leukotriene B4; Male; Mesocricetus; Mouth Neoplasms; Precancerous Conditions; Random Allocation; Triterpenes

Arachidonic acid (AA) is the major precursor of several classes of signal molecules and the alteration of its metabolism is involved in human carcinogenesis. For instance, 5-lipoxygenase (5-LOX) converts AA to hydroxyeicosatetraenoic acids or leukotrienes (LTs), which are able to enhance proliferation, increase survival and suppress the apoptosis of human cells. To determine the potential use of 5-LOX inhibitors in the prevention of esophageal cancer, we first analyzed the 5-LOX expression in esophageal tissue samples using immunohistochemistry and then examined the effect of the 5-LOX inhibitors AA861 and REV5901 on cell viability and apoptosis in esophageal cancer cell lines. 5-LOX expression was present in 79% (127/161) of esophageal cancer but in only 13% (4/32) of normal esophageal mucosa. 5-LOX was also expressed in all the eight esophageal cancer cell lines. Moreover, 5-LOX inhibitors caused a dose- and time-dependent reduction of cell viability, which was due to the induction of apoptosis and associated with LTB4 suppression. Our data also showed that both LTB4, a product of 5-LOX and LTB4 receptor antagonist U-75302 were able to prevent AA861 and REV5901 on induction of apoptosis. The present study demonstrated that 5-LOX protein expression is increased in esophageal cancer and that 5-LOX inhibitors can induce esophageal cancer cells to undergo apoptosis, suggesting that 5-LOX may be an effective target in the prevention of esophageal cancer.

Topics: Adenocarcinoma; Apoptosis; Arachidonate 15-Lipoxygenase; Arachidonate 5-Lipoxygenase; Benzoquinones; Carcinoma, Squamous Cell; Cell Differentiation; Cell Survival; Esophageal Neoplasms; Esophagus; Fatty Alcohols; Female; Glycols; Humans; Immunoenzyme Techniques; Leukotriene B4; Lipoxygenase Inhibitors; Lymphatic Metastasis; Male; Middle Aged; Receptors, Leukotriene B4; Tumor Cells, Cultured

A murine model (C3H mice) of squamous cell carcinoma (SCCVII) has been used to investigate the role of arachidonic acid (AA) metabolites in head and neck cancer. Inhibition of tumor growth by cyclooxygenase (COX) and lipoxygenase (LOX) inhibitors of AA metabolism has been associated with changes in levels of AA metabolites in tumor tissues and inflammatory cell infiltrates. To characterize this model further, the effects of exogenous AA metabolites on tumor growth in vitro and in vivo were investigated.. Following subcutaneous inoculation with SCCVII tumor cells, control (16 mice) and treatment (24 mice) groups were injected with peritumoral vehicle or AA metabolite. Peritumoral injections of prostaglandin E2 (PGE2), leukotriene B4 (LTB4), and 12-hydroxyeicosatetraenoic acid (12-HETE) were performed for 16-21 days, and final excised tumor weights were measured. In vitro production of PGE2 and LTB4 was assayed in 2-5 day cultures of SCCVII. Exogenous PGE2 effects on tumor cell growth was assessed with the MTT assay in vitro.. Tumor growth was significantly inhibited (p =.03) following peritumoral injection of PGE2. Final tumor weights were not affected by LTB4 or 12-HETE. Tumor inhibition by PGE2 was associated with increased tumor tissue levels of LTB4 (p =.04). In vitro, SCCVII produced minimal amounts of PGE2 and LTB4, and PGE2 had minimal effect on growth.. In this model, tumor inhibition by exogenous PGE2 is primarily mediated by affecting host-tumor interactions, although there may be some direct effect on tumor cells. Changes in tumor tissue levels of LTB4 following peritumoral PGE2 administration may be attributable to negative feedback inhibition of the COX pathway with shunting into the LOX pathway. SCCVII cells are probably not a significant source of prostaglandins and leukotrienes in vivo. These data provide insight into the mechanism of action of inhibitors of AA metabolism on tumor growth.

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; Animals; Arachidonic Acids; Carcinoma, Squamous Cell; Cell Division; Cells, Cultured; Dinoprostone; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Female; Head and Neck Neoplasms; Injections, Intralesional; Leukotriene B4; Mice; Mice, Inbred C3H; Reference Values

Topics: Arachidonic Acid; Carcinoma, Squamous Cell; Cell Line; Dinoprostone; Epithelial Cells; Head and Neck Neoplasms; Humans; Hydroxyeicosatetraenoic Acids; Keratinocytes; Leukotriene B4; Mucous Membrane; Palatine Tonsil; Precancerous Conditions; Reference Values; Trachea; Tumor Cells, Cultured

Topics: Adult; Aged; Arachidonic Acids; Carcinoma, Squamous Cell; Dinoprostone; Female; Head and Neck Neoplasms; Humans; Hydroxyeicosatetraenoic Acids; Leukotriene B4; Male; Middle Aged; Neoplasm Staging; Reference Values; Saliva

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; Adenocarcinoma; Calcimycin; Carcinoma, Small Cell; Carcinoma, Squamous Cell; Cell Communication; Cell Line; Coculture Techniques; Erythrocytes; Humans; Hydroxyeicosatetraenoic Acids; Leukotriene B4; Lung Neoplasms; Models, Biological; Neutrophils; Phospholipases A; Phospholipases A2; Tumor Cells, Cultured

To determine the role of metabolites of arachidonic acid in the growth of squamous cell carcinomas of the head and neck.. Investigation of the effect of a cyclooxygenase inhibitor, piroxicam, on the growth of squamous cell carcinoma in a murine model.. C3H/HeJ mice bearing squamous cell carcinoma (SCCVII) were treated with piroxicam (0.08 mg/d, orally) for 30 days beginning 1 day before tumor inoculation.. Decrease in tumor volumes and tumor growth rates.. Significant inhibition of tumor growth (P = .002) and final tumor weight (P = .0007) was noted in the group receiving piroxicam therapy. Prostaglandin E2 levels in the tumor tissue were unrelated to treatment or tumor size. Increased levels of leukotriene B4 were observed in the piroxicam-treated group (P = .03), and larger tumors were associated with decreased leukotriene B4 levels (P = .0001).. Cyclooxygenase inhibitors may be effective in the treatment of some squamous cell carcinomas. The therapeutic effect of cyclooxygenase inhibitors may result from shunting into the lipoxygenase pathway of arachidonic acid metabolism.

Topics: Animals; Arachidonic Acid; Carcinoma, Squamous Cell; Dinoprostone; Female; Head and Neck Neoplasms; Leukotriene B4; Mice; Mice, Inbred C3H; Piroxicam

To characterize the presence and production of various phospholipid metabolites by head and neck squamous cell carcinoma (HNSCC) and squamous cell carcinoma cell lines in vitro and in vivo.. The HNSCC tumor homogenates and supernatants of HNSCC tumor cultures and established squamous cell carcinoma cell lines were assayed for prostaglandin E2 (PGE2), leukotriene B4 (LTB4), and platelet activating factor (PAF). In vitro experiments were carried out under baseline conditions or with exposure to several known immunomodulators (epidermal growth factor, bacterial lipopolysaccharide, and interleukin 1).. The HNSCC tumor tissue was obtained from primary tumor or cervical lymph node metastasis of surgical resections.. Prostaglandin E2, LTB4, and PAF were measured in tumor homogenates and cell culture supernatants using standardized radioimmunoassay kits.. All tumor homogenates (eight of eight) contained detectable levels of PGE2 (range, 324 to 2258 pg/g of tumor tissue) and LTB4 (range, 790 to 41,900 pg/g of tumor tissue); PAF was detected in six of eight homogenates (range, 7362 to 40,788 pg/g of tumor tissue). All of the short-term primary HNSCC tumor cultures and squamous carcinoma lines produced PGE2 (range, 90 to 1160 pg/10(6) cells), and half of the cultures produced LTB4 (range, 100 to 1700 pg/10(6) cells); none of the cultures or cell lines produced detectable levels of PAF. Interleukin 1 significantly enhanced production of PGE2 by tumor cultures (P < .02). Characterization of tumor cultures with a fibroblast antibody marker, BR2, revealed that 26% to 64% of tumor culture cells were fibroblasts.. Prostaglandin E2, LTB4, and PAF are present in the tumor microenvironment, where they may be involved in the local immunosuppression phenomenon seen in HNSCC. Both PGE2 and LTB4 were produced in vitro by tumor cultures and squamous cell carcinoma cell lines; PAF was not produced by tumor cultures in vitro and therefore may be a product of local immune cells in HNSCC in vivo. Interleukin 1 and PGE2 may interact in immunoregulation in the HNSCC tumor microenvironment.

Topics: Aged; Analysis of Variance; Animals; Carcinoma, Squamous Cell; Dinoprostone; Epidermal Growth Factor; Evaluation Studies as Topic; Fibroblasts; Head and Neck Neoplasms; Humans; Immune Tolerance; Interleukin-1; Leukotriene B4; Lipopolysaccharides; Middle Aged; Neoplasm Staging; Phenotype; Platelet Activating Factor; Radioimmunoassay; Regression Analysis; Tumor Cells, Cultured

Alterations in the production of arachidonic acid metabolites by squamous epithelium of the upper aerodigestive tract may play a role in the pathogenesis of squamous cell carcinoma of the head and neck. The levels of cyclooxygenase and lipoxygenase metabolites of arachidonic acid metabolism were measured by radioimmunoassay in the saliva of 51 patients with squamous cell carcinoma of the head and neck and compared with a control group of 27 patients with no history of cancer. Levels of leukotriene B4 were significantly increased in cancer patients (p = 0.02), whereas there were no significant differences in levels of prostaglandin E2 or 15-hydroxy-eicosatetranoic acid. Levels of metabolites did not correlate with a history of tobacco use and did not change in a consistent manner after surgery. The significance of arachidonic acid metabolites in the saliva of patients with squamous cell carcinoma of the head and neck is unknown.

Topics: Adult; Aged; Arachidonic Acid; Carcinoma, Squamous Cell; Case-Control Studies; Dinoprostone; Female; Head and Neck Neoplasms; Humans; Hydroxyeicosatetraenoic Acids; Leukotriene B4; Male; Middle Aged; Neoplasm Staging; Prognosis; Saliva

SC-41930, 7-[3-(4-acetyl-3-methoxy-2-propylphenoxy)-propoxyl]-3, 4-dihydro-8-propyl-2H-1-benzopyran-2-carboxylic acid, a potent leukotriene-B4 (LTB4) receptor antagonist, inhibits in vivo 12-hydroxyeicosatetraenoic acid (12-HETE)-induced neutrophil infiltration, suggesting a potential 12-HETE receptor antagonist effect, as well. Since 12-HETE is assumed to have a pathophysiological role in inflammatory skin diseases, and epidermal cells possess high affinity binding sites for 12(S)-HETE, we studied the effect of SC-41930 on 12(S)-HETE binding to the human epidermal cell line, SCL-II. SC-41930 antagonized the 12(S)-HETE binding to SCL-II cells with a Ki of 480 nM. This Ki value is similar to that obtained for the inhibition of LTB4 binding to human neutrophils. Our results show that SC-41930, in addition to its LTB4 receptor antagonist effect, exhibits 12-HETE receptor antagonist effect as well, and therefore may be of benefit in skin diseases with elevated 12-HETE levels.

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; Benzopyrans; Carcinoma, Squamous Cell; Epidermis; Humans; Hydroxyeicosatetraenoic Acids; Leukotriene B4; Neutrophils; Receptors, Immunologic; Receptors, Leukotriene B4; Tumor Cells, Cultured

The quantitation of leukotriene B4 (LTB4) in induced squamous cell carcinoma (SCC) of the Syrian hamster cheek pouch and histologically proven human oral SCC was investigated by a combination of reverse phase-high performance liquid chromatography (RP-HPLC) and radioimmunoassay (RIA). Healthy tissue obtained from these same patients and animals treated with vehicle alone were used as controls. From both animal and human studies our results show a 10 to 30 fold increase in the levels of LTB4 found in tumour compared to control tissue. Furthermore, this dihydroxy acid was not detected in the mucosal tissue of normal subjects undergoing routine surgery. Since LTB4 is a potent inflammatory mediator and modulator of immune responses, its presence at biologically active concentrations in human squamous cell carcinoma suggests a possible role in the pathogenesis of head and neck cancer.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Adult; Aged; Aged, 80 and over; Animals; Biomarkers, Tumor; Carcinoma, Squamous Cell; Cricetinae; Female; Humans; Leukotriene B4; Male; Mesocricetus; Middle Aged; Mouth Mucosa; Mouth Neoplasms

Topics: Animals; Carcinoma, Squamous Cell; Cricetinae; Head and Neck Neoplasms; Humans; Leukotriene B4; Mesocricetus

We identified leukotriene B4 (LTB4)/12-hydroxyeicosatetraenoic acid (12-HETE) binding sites in a squamous cell cancer-derived human epidermal cell line. Analysis of the binding data revealed a single class of binding sites with a dissociation constant of 0.16 microM and a Bmax of 3.8 x 10(6) sites per cell. Competitive binding assays with various eicosanoids at 37 degrees C showed nearly equal binding of 12(S)-HETE, 12(R)-HETE and LTB4. 5(S)-HETE and LTB4-analogs bound with lesser affinity. Specific LTB4 binding at 37 degrees C could also be demonstrated in freshly isolated normal human keratinocytes. Since lipoxygenase-derived eicosanoids are thought to play an important role in hyperproliferative and inflammatory skin diseases, the identification of LTB4/12-HETE binding sites in keratinocytes could have implications for the development of new drugs controlling these disease processes.

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; Binding Sites; Binding, Competitive; Carcinoma, Squamous Cell; Cell Line; Epidermis; Humans; Hydroxyeicosatetraenoic Acids; Isomerism; Leukotriene B4