mobic and Hypoxia

T7 peptide is considered as an antiangiogenic polypeptide. The presents study aimed to further detect the antiangiogenic mechanisms of T7 peptide and determine whether combining T7 peptide and meloxicam (COX-2/PGE2 specific inhibitor) could offer a better therapy to combat hepatocellular carcinoma (HCC). T7 peptide suppressed the proliferation, migration, tube formation, and promoted the apoptosis of endothelial cells under both normoxic and hypoxic conditions via integrin α3β1 and αvβ3 pathways. Cell proliferation, migration, apoptosis, or tube formation ability were detected, and the expression of integrin-associated regulatory proteins was detected. The anti-tumor activity of T7 peptide, meloxicam, and their combination were evaluated in HCC tumor models established in mice. T7 peptide suppressed the proliferation, migration, tube formation, and promoted the apoptosis of endothelial cells under both normoxic and hypoxic conditions via integrin α3β1 and αvβ3 pathways. Meloxicam enhanced the activity of T7 peptide under hypoxic condition. T7 peptide partly inhibited COX-2 expression via integrin α3β1 not αvβ3-dependent pathways under hypoxic condition. T7 peptide regulated apoptosis associated protein through MAPK-dependent and -independent pathways under hypoxic condition. The MAPK pathway was activated by the COX-2/PGE2 axis under hypoxic condition. The combination of T7 and meloxicam showed a stronger anti-tumor effect against HCC tumors in mice. The data highlight that meloxicam enhanced the antiangiogenic activity of T7 peptide

Topics: Animals; Apoptosis; Carcinoma, Hepatocellular; Cell Line, Tumor; Cell Proliferation; Collagen Type IV; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Dinoprostone; Drug Combinations; Endothelial Cells; Humans; Hypoxia; Integrins; Liver Neoplasms; Meloxicam; Mice; Neovascularization, Pathologic; Peptide Fragments; Random Allocation; RNA, Small Interfering; Xenograft Model Antitumor Assays

Hypoxia-induced up-regulation of vascular endothelial growth factor (VEGF) expression is a critical event leading to tumor neovascularization. Hypoxia stimulates hypoxia-inducible factor-1alpha (HIF-1alpha), a transcriptional activator of VEGF. Cyclooxygenase (COX)-2, an inducible enzyme that catalyzes the formation of prostaglandins (PGs) from arachidonic acid, is also induced by hypoxia. We reported previously that COX-2 inhibition prevents hypoxic up-regulation of VEGF in human prostate cancer cells and that prostaglandin E(2) (PGE(2)) restores hypoxic effects on VEGF. We hypothesized that PGE(2) mediates hypoxic effects on VEGF by modulating HIF-1alpha expression. Addition of PGE(2) to PC-3ML human prostate cancer cells had no effect on HIF-1alpha mRNA levels. However, PGE(2) significantly increased HIF-1alpha protein levels, particularly in the nucleus. This effect of PGE(2) largely results from the promotion of HIF-1alpha translocation from the cytosol to the nucleus. PGE(2) addition to PC-3 ML cells transfected with a GFP-HIF-1alpha vector induced a time-dependent nuclear accumulation of the HIF-1alpha protein. Two selective COX-2 inhibitors, meloxicam and NS398, decreased HIF-1alpha levels and nuclear localization, under both normoxic and hypoxic conditions. Of several prostaglandins tested, only PGE(2) reversed the effects of a COX-2 inhibitor in hypoxic cells. Finally, PGE(2) effects on HIF-1alpha were specifically inhibited by PD98059 (a MAPK inhibitor). These data demonstrate that PGE(2) production via COX-2-catalyzed pathway plays a critical role in HIF-1alpha regulation by hypoxia and imply that COX-2 inhibitors can prevent hypoxic induction of HIF-mediated gene transcription in cancer cells.

Topics: Active Transport, Cell Nucleus; Arachidonic Acid; Catalysis; Cell Nucleus; Culture Media, Serum-Free; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Cyclooxygenase Inhibitors; Cytosol; Dinoprostone; Endothelial Growth Factors; Enzyme Inhibitors; Flavonoids; Green Fluorescent Proteins; Humans; Hypoxia; Hypoxia-Inducible Factor 1, alpha Subunit; Immunoblotting; Intercellular Signaling Peptides and Proteins; Isoenzymes; Luminescent Proteins; Lymphokines; Male; MAP Kinase Signaling System; Meloxicam; Membrane Proteins; Nitrobenzenes; Phosphatidylinositol 3-Kinases; Prostaglandin-Endoperoxide Synthases; Prostaglandins; Prostatic Neoplasms; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Sulfonamides; Thiazines; Thiazoles; Time Factors; Transcription Factors; Transcription, Genetic; Transfection; Tumor Cells, Cultured; Up-Regulation; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors