15-hydroxy-5-8-11-13-eicosatetraenoic-acid and Lung-Neoplasms

15-Lipoxygenase-2 (15-LOX-2) and 15(S)-hydroxyeicosatetraenoic acid (15(S)-HETE) have been considered as latent mediators of diverse biological processes including cancer. However, their functions in lung adenocarcinoma (LAC) are unclear. In this study, we aimed to determine whether 15-LOX-2/15(S)-HETE is involved in the proliferation and migration of A549 cells and to identify the signaling pathways that participate in this process. We used immunohistochemistry to identify the expression levels of 15-LOX-2 in lung cancer tissue samples. The effects of 15(S)-HETE on the proliferation and migration of A549 cells under hypoxic conditions were assessed by cell viability assays, immunofluorescence, western blotting, scratch wound assays and transwell assays. We found that the expression of 15-LOX-2 was significantly up-regulated in LAC tissue samples compared with adjacent normal tissue samples. The content of 15(S)-HETE in A549 cells was increased under hypoxic conditions. Moreover, 15(S)-HETE could stimulate the expression of PCNA, cyclin A and cyclin D. In addition, siRNA of 15-LOX-2 inhibited the proliferation and migration of A549 cells in vitro. Our data also provide novel evidence demonstrating that the STAT3 pathway participates in the 15(S)-HETE-induced proliferation and migration of A549 cells. This study may provide a greater understanding of LAC metastasis and shed new light on the mechanisms by which the 15(S)-HETE/STAT3 pathway is related to this disease.

Topics: A549 Cells; Adenocarcinoma; Arachidonate 15-Lipoxygenase; Cell Hypoxia; Cell Movement; Cell Proliferation; Cell Survival; Humans; Hydroxyeicosatetraenoic Acids; Lung Neoplasms; Neoplasm Metastasis; RNA Interference; Signal Transduction; STAT3 Transcription Factor

12/15-Lipoxygenase (12/15-LOX) is a non-haeme iron-containing dioxygenase that forms 12(S)-hydroxyeicosatetraenoic acid (12(S)-HETE) or 15(S)-HETE. Several biological mediators including cytokines, growth factors and lipid metabolites released during tumour cell-endothelial cell adhesion are associated with malignant tumour progression. Here we found that HETEs released from the host organ played a critical role in tumour metastasis. Intravenous injection of B16F10 melanoma cells caused lung nodule formation, which was markedly attenuated in 12/15-LOX null mice. Co-injection of melanoma cells with 12(S)-HETE increased the lung homing activity of B16F10 melanoma cells. In vitro studies showed that 12(S)-HETE and 15(S)-HETE treatment resulted in a concentration-dependent increase of adhesion of B16F10 cells on collagen or fibronectin. The melanoma cell adhesion was then evaluated in pulmonary primary cell culture isolated from wild-type (WT) and 12/15-LOX knockout (KO) mice. It was found that the adhesion of melanoma cells on the epithelial cells isolated from 12/15-LOX null mice was reduced in comparison with those isolated from WT mice. Treatment of 12(S)-HETE increased the pFAK in melanoma cells adhering on collagen-coated slide. The enhancement of adherence elicited by 12(S)-HETE in B16F10 cells could be antagonised by focal adhesion kinase (FAK) inhibitor 14 (FAK inhibitor) or PD98059 (extracellular signal-regulated kinase (ERK) inhibitor). 12(S)-HETE increased the phosphorylation of FAK and ERK in adhering melanoma cells. The FAK phosphorylation induced by 12(S)-HETE was further inhibited by PD98059, indicating that FAK is the downstream target of ERK. The adhesion and lung metastasis of human melanoma cells of C32 in NOD/SCID mice were also potentiated by co-treatment with 12(S)-HETE. These results demonstrate that 12(S)-HETE/15(S)-HETE activates ERK and FAK signalling pathways, thereby upregulates the adhesion and metastatic potential of melanoma cells. The endogenous release of 12(S)-HETE/15(S)-HETE in the host organ may affect the metastatic potential of melanoma.

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; Animals; Arachidonate 12-Lipoxygenase; Arachidonate 15-Lipoxygenase; Blotting, Western; Cell Adhesion; Cell Line, Tumor; Collagen; Disease Progression; Epithelial Cells; Extracellular Signal-Regulated MAP Kinases; Fibronectins; Focal Adhesion Protein-Tyrosine Kinases; Humans; Hydroxyeicosatetraenoic Acids; Lung Neoplasms; Melanoma, Experimental; Mice; Mice, Inbred C57BL; Mice, Inbred NOD; Mice, Knockout; Mice, SCID; Signal Transduction; Transplantation, Heterologous; Tumor Cells, Cultured

Pioglitazone (PGZ), a synthetic peroxisome proliferator-activated receptor gamma (PPARγ) ligand, is known to have anti-tumor activity by inducing tumor cell apoptosis. However, it is unknown whether it can be used to prevent smoking carcinogen-induced lung tumor development. We induced mouse lung tumors using smoking carcinogen 4- methylnitrosamino-l-3-pyridyl-butanone (NNK). PGZ was given at two early stages before the tumor formation. The role and the functional mechanism of PGZ were investigated in the development of mouse pulmonary tumors. The tumor development was monitored and PPARγ activity and endogenous PPARγ ligands 15(S)-HETE, 13(S)-HODE were determined. The application of PGZ before alveolar hyperplasia formation (Group NPa) and at the early phase of alveolar hyperplasia formation (Group NPb) significantly prevented the lung tumor development especially in Group NPb mice (all p < 0.05). PGZ not only prevented the NNK-mediated reduction of endogenous ligands 15(S)-HETE and 13(S)-HODE, but also increased 13(S)-HODE level in Group NPb mice. PPARγ transcriptional activity was increased in NNKstimulated lung tissues when PGZ was given. The in vivo results were confirmed in the human lung cancer cells, which showed that PGZ induced lung cancer cell apoptosis through up-regulating nuclear PPARγ expression, inducing PPARγ transcriptional activity and increasing the levels of PPARγ ligands in NNK-treated cells. The early application of PGZ is able to prevent NNK-induced lung tumor development through maintaining the level of endogenous PPARγ ligands 15(S)-HETE and 13(S)-HODE and activation of PPARγ.

Topics: Animals; Anticarcinogenic Agents; Apoptosis; Cell Line, Tumor; Cell Proliferation; Cell Transformation, Neoplastic; Gene Expression Regulation, Neoplastic; Humans; Hydroxyeicosatetraenoic Acids; Hyperplasia; Ligands; Linoleic Acids; Lung Neoplasms; Mice; Nitrosamines; Pioglitazone; PPAR gamma; Pulmonary Alveoli; Smoking; Thiazolidinediones; Time Factors; Transcription, Genetic

Peroxisome proliferator-activated receptor (PPAR)-α and PPARγ participate in cell proliferation and apoptosis. Few studies have simultaneously investigated both PPARα and PPARγ in lung cancers in vivo. The roles of PPARα and -γ were investigated in the development of pulmonary tumors induced in the adult A/J mouse by treatment with 4-(methylnitrosamino)-l-(3-pyridyl)-lbutanone (NNK). Compared with the normal lung tissues, PPARγ expression was much higher in the NNK-induced lung tumor tissues. However, PPARγ transcriptional activity, and the levels of two major endogenous PPARγ ligands, 13-hydroxyoctadecadienoic acid and 15-hydroxyeicosatetraenoic acid, were significantly lower in the NNK-treated lung tissues. The ligand changes in mice were confirmed in human lung cancer tissues. Along with the alteration of PPARγ and its endogenous ligands, the level of PPARα and its activity were increased in the NNK-induced mouse lung tumors. Treatment of mice with the synthetic PPARγ ligand, pioglitazone, significantly inhibited the formation of mouse lung tumors induced by NNK. Our study demonstrated that the reduction of endogenous PPARγ ligands and increased PPARα occurred before the formation of lung tumors, indicating that the molecular changes play a role in lung carcinogenesis. The results suggest that the enhancement of PPARγ activity with its ligands, and the suppression of PPARα with its inhibitors, may prevent the formation of lung tumors, as well as accelerate the therapy of lung cancer. Our findings may also reveal the possibility of using the level of endogenous PPARγ ligands and the activities of PPARγ or PPARα as tumor markers for lung cancer.

Topics: Animals; Carcinoma, Non-Small-Cell Lung; Disease Progression; Female; Gene Expression Regulation, Neoplastic; Humans; Hydroxyeicosatetraenoic Acids; Ligands; Linoleic Acids; Lipid Metabolism; Lung Neoplasms; Male; Mice; Nitrosamines; Pioglitazone; PPAR alpha; PPAR gamma; Precancerous Conditions; Retinoid X Receptor alpha; Signal Transduction; Thiazolidinediones; Transcription, Genetic

15-S-Hydroxyeicosatetraenoic acid (15(S)-HETE) and 13-S-hydroxyoctadecadienoic acid (13(S)-HODE), both of which are metabolites of 15-lipoxygenases (15-LOXs), are endogenous ligands for peroxisome proliferator-activated receptor gamma (PPARgamma). The activation of PPARgamma inhibits cell growth and induces apoptosis in some cancers. The role of 15(S)-HETE) and 13(S)-HODE in the development of lung cancer is not clear.. 15-LOXs, 15(S)-HETE and 13(S)-HODE were monitored during the development of mouse lung tumours induced by the tobacco smoke carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and the levels of these markers were determined in 54 human non-small cell lung cancers.. 15-LOXs, 15(S)-HETE and 13(S)-HODE levels were significantly reduced in human lung cancer tissue compared with non-tumour lung tissue (p=0.011 and p=0.022, respectively). In mouse experiments, 15(S)-HETE and 13(S)-HODE started to reduce at 26 and 30 weeks, respectively, after NNK treatment. The time frame of 15(S)-HETE reduction was in line with the decrease in 12/15-LOX mRNA and protein. A significant difference in the number of tumours in NNK-treated mice and controls was not observed until week 34 (p<0.05) and week 38 (p<0.01). The reduction in 12/15-LOX and 15(S)-HETE therefore predated the appearance of lung tumour. Furthermore, PPARgamma activity was decreased in NNK-treated mouse lungs compared with the control, and the decreased PPARgamma activity occurred at the same time points as the reduction in 12/15-LOX and 15(S)-HETE.. These findings indicate that the reduction in 15-LOX, 15(S)-HETE and 13(S)-HODE results in the decreased PPARgamma activity seen in lung tumours and contributes to the development of lung tumours induced by tobacco smoking.

Topics: Animals; Arachidonate 15-Lipoxygenase; Biomarkers, Tumor; Carcinoma, Non-Small-Cell Lung; Cell Transformation, Neoplastic; Disease Models, Animal; Disease Progression; Female; Humans; Hydroxyeicosatetraenoic Acids; Linoleic Acids; Lung; Lung Neoplasms; Mice; Mice, Inbred A; Neoplasm Proteins; Nitrosamines; PPAR gamma

Emerging preclinical data suggests that tea possess anticarcinogenic and antimutagenic properties. We therefore hypothesize that white tea extract (WTE) is capable of favorably modulating apoptosis, a mechanism associated with lung tumorigenesis. We examined the effects of physiologically relevant doses of WTE on the induction of apoptosis in non-small cell lung cancer cell lines A549 (adenocarcinoma) and H520 (squamous cell carcinoma) cells. We further characterized the molecular mechanisms responsible for WTE-induced apoptosis, including the induction of peroxisome proliferator-activated receptor-gamma (PPAR-gamma) and the 15-lipoxygenase (15-LOX) signaling pathways. We found that WTE was effective in inducing apoptosis in both A549 and H520 cells, and inhibition of PPAR-gamma with GW9662 partially reversed WTE-induced apoptosis. We further show that WTE increased PPAR-gamma activation and mRNA expression, concomitantly increased 15(S)-hydroxy-eicosatetraenoic acid release, and upregulated 15-LOX-1 and 15-LOX-2 mRNA expression by A549 cells. Inhibition of 15-LOX with nordihydroguaiaretic acid (NGDA), as well as caffeic acid, abrogated WTE-induced PPAR-gamma activation and upregulation of PPAR-gamma mRNA expression in A549 cells. WTE also induced cyclin-dependent kinase inhibitor 1A mRNA expression and activated caspase-3. Inhibition of caspase-3 abrogated WTE-induced apoptosis. Our findings indicate that WTE is capable of inducing apoptosis in non-small cell lung cancer cell lines. The induction of apoptosis seems to be mediated, in part, through the upregulation of the PPAR-gamma and 15-LOX signaling pathways, with enhanced activation of caspase-3. Our findings support the future investigation of WTE as an antineoplastic and chemopreventive agent for lung cancer.

Topics: Anilides; Apoptosis; Arachidonate 15-Lipoxygenase; Carcinoma, Non-Small-Cell Lung; Catechin; Drug Evaluation, Preclinical; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Neoplastic; Hormone Antagonists; Humans; Hydroxyeicosatetraenoic Acids; Lung Neoplasms; Plant Extracts; PPAR gamma; Tea; Tumor Cells, Cultured

The influence of inhibitors of different lipoxygenases (LOX) on the growth of human tumor cells with different profiles of synthesized eicosanoids was studied. The studied LOX inhibitors had virtually no influence on the growth of A549 cells actively synthesizing cyclooxygenase and lipoxygenase metabolites of arachidonic acid (AA). The inhibitor of 12-LOX, baicalein, significantly inhibited proliferation in cultures of A431 epidermoid carcinoma cells with a characteristic domination of the major lipoxygenase metabolite of AA, 12-hydroxyeicosatetraenoic acid (12-HETE), in the profile of synthesized eicosanoids and reduced to 70% the incorporation of [3H]thymidine into DNA. Treatment of these cultures with 12-HETE virtually restored the growth potential of the tumor cells. The findings suggest that the lipoxygenase metabolite of AA, 12-HETE, is a growth-limiting factor for tumor cells of definite type.

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; Adenocarcinoma; Arachidonate Lipoxygenases; Arachidonic Acid; Carcinoma, Squamous Cell; Cell Proliferation; Flavanones; Humans; Hydroxyeicosatetraenoic Acids; Lung Neoplasms; Nitrobenzenes; Salicylamides; Sulfonamides; Tumor Cells, Cultured; Umbelliferones

The proinflammatory cytokine IL-4 is secreted in large amounts during allergic inflammatory response in asthma and plays a pivotal role in the airway inflammation. IL-4 has been shown to up-regulate 15-lipoxygenase and produce 15(S)-hydroxyeicosatetraenoic acid (15(S)-HETE) in A549 cells via the Janus kinase/STAT6 pathway under coactivation of CREB binding protein/p300. IL-4 has also been shown to up-regulate peroxisome proliferator-activated receptor gamma (PPARgamma) nuclear receptors in macrophages and A549 cells. In this study we demonstrate that 15(S)-HETE binds to PPARgamma nuclear receptors and induces apoptosis in A549 cells. Moreover, pretreatment of cells with nordihydroguaiaretic acid, a 15-lipoxygenase inhibitor, prevented PPARgamma activation and apoptosis. The latter was accomplished by the interaction of the 15(S)-HETE/PPARgamma complex with the adapter protein Fas-associating protein with death domain and caspase-8, as shown by transfection of Fas-associating protein with death domain dominant negative vector and cleavage of caspase 8 to active subunits p41/42 and p18. Whereas IL-4 and PPARgamma ligands failed to induce cleavage of Bid and release of cytochrome c from mitochondria, they caused translocation of the proapoptotic protein Bax from cytoplasm to mitochondria with a concomitant decrease in the Bcl-x(L) level. We therefore believe that in unstimulated cells Bcl-x(L) and Bax form a heterodimer, in which Bcl-x(L) dominates and prevents the induction of apoptosis, whereas in IL-4-stimulated cells the 15(S)-HETE/PPARgamma complex down-regulates Bcl-x(L), and the resulting overweight of Bax commits the cell to apoptosis via caspase-3. However, this pathway does not rule out the direct caspase-8-mediated activation of caspase-3. In conclusion, IL-4-induced apoptosis may contribute to severe loss of alveolar structures and infiltration of eosinophils, mononuclear phagocytes, etc., into the lung tissue of chronic asthma patients.

Topics: Adaptor Proteins, Signal Transducing; Adenocarcinoma; Apoptosis; bcl-2-Associated X Protein; bcl-X Protein; BH3 Interacting Domain Death Agonist Protein; Binding Sites; Carrier Proteins; Caspase 8; Caspase 9; Caspases; DNA-Binding Proteins; Down-Regulation; Fas-Associated Death Domain Protein; Humans; Hydrolysis; Hydroxyeicosatetraenoic Acids; Interleukin-4; Ligands; Lung Neoplasms; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Receptors, Cytoplasmic and Nuclear; Signal Transduction; Transcription Factors; Tumor Cells, Cultured; Up-Regulation

Bronchitis, asthma, and cystic fibrosis, marked by inflammation and mucus hypersecretion, can be caused or exacerbated by airway pathogens or irritants including acrolein, an aldehyde present in tobacco smoke. To determine whether acrolein and inflammatory mediators alter mucin gene expression, steady-state mRNA levels of two airway mucins, MUC5AC and MUC5B, were measured (by RT-PCR) in human lung carcinoma cells (NCI-H292). MUC5AC mRNA levels increased after >/=0.01 nM acrolein, 10 microM prostaglandin E2 or 15-hydroxyeicosatetraenoic acid, 1.0 nM tumor necrosis factor-alpha (TNF-alpha), or 10 nM phorbol 12-myristate 13-acetate (a protein kinase C activator). In contrast, MUC5B mRNA levels, although easily detected, were unaffected by these agonists, suggesting that irritants and associated inflammatory mediators increase mucin biosynthesis by inducing MUC5AC message levels, whereas MUC5B is constitutively expressed. When transcription was inhibited, TNF-alpha exposure increased MUC5AC message half-life compared with control level, suggesting that transcript stabilization is a major mechanism controlling increased MUC5AC message levels. Together, these findings imply that irritants like acrolein can directly and indirectly (via inflammatory mediators) increase airway mucin transcripts in epithelial cells.

Topics: Acrolein; Carcinoma, Mucoepidermoid; Dinoprostone; Gene Expression Regulation; Humans; Hydroxyeicosatetraenoic Acids; Inflammation; Kinetics; Lung Neoplasms; Mucin 5AC; Mucin-5B; Mucins; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Tetradecanoylphorbol Acetate; Transcription, Genetic; Tumor Cells, Cultured; Tumor Necrosis Factor-alpha

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; Arachidonic Acid; Humans; Hydroxyeicosatetraenoic Acids; Lung Neoplasms; Neoplasm Metastasis

It is known that change in the arachidonic acid metabolism plays an important role in the development of tumors. This study was undertaken to understand the relationship of changes in lipoxygenase, cyclooxygenase and ornithine decarboxylase (ODC) to the inhibitory effect of vitamin E on urethane-induced lung tumorigenesis in mice. We analyzed the inhibitory effect of vitamin E on ornithine decarboxylase, cyclooxygenase and lipoxygenase activities at a promotion phase of lung tumorigenesis in mice. An increase in the ODC of urethane treated-mice and no significant change in the ODC of VE-treated mice were observed. An increase in the production of PGE2 and all HETES tested in the lungs of the urethane-treated mice was observed at week 8 after injection (promotion phase), showing a significant difference compared to the control group. Excessive vitamin E feeding during the initiation or promotion phases inhibited the increase in PGE2 and HETES produced by urethane treatment. These results suggest that the suppression of prostagrandin metabolism and ODC may be associated with the inhibitory effect of vitamin E against urethane-induced lung tumorigenesis.

Topics: Animals; Arachidonic Acid; Cyclooxygenase Inhibitors; Dinoprostone; Enzyme Inhibitors; Hydroxyeicosatetraenoic Acids; Lipoxygenase Inhibitors; Lung Neoplasms; Male; Mice; Ornithine Decarboxylase Inhibitors; Urethane; Vitamin E

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; Arachidonic Acid; Carbon Radioisotopes; Humans; Hydroxyeicosatetraenoic Acids; Lung Neoplasms; Neoplasm Metastasis