Serious cardiovascular side effects are reported from synthetic cyclooxygenase-2 (COX-2) selective nonsteroidal anti-inflammatory drugs, the most common medication for rheumatoid arthritis (RA) and osteoarthritis (OA). Natural products from herbal medicine are inspirational source of safe and effective remedy due to its distinguished chemical diversity. Nanomagnetic ligand fishing using enzyme-anchored-magnetic nanoparticles (MNPs) is an advanced selective bioseparation strategy based on macromolecular target-ligand binding, which can screen enzyme inhibitors from complex mixtures. "Snow lotus" herbs have been clinically applied as safe and effective treatment for arthritis throughout centuries in Asia. Some major chemicals from the herbs have been found with anti-COX-2 activities. It is therefore hypothesized that novel and safe COX-2 selective inhibitors can be separated from a most representative snow lotus herb via ligand fishing using COX-2-functionalized MNPs (COX-2-MNPs), and that the efficacy and safety of the screened COX-2 ligands can be verified by subsequent evaluation. Saussurea laniceps Hand.-Mazz. (SL), S. medusa Maxim. (SM) and S. involucrata (Kar. et Kir.) Sch.Bip. (SI) are three authenticated sources of "snow lotus" herbs. An ultra-high performance liquid chromatography hyphenated with diode array detector and quadrupole time of flight-mass spectrometry (UPLC-DAD-QTOF-MS) method was developed to analyze 49 herbal samples for species analysis and overall quality evaluation. With 25 simultaneously identified constituents, of which 12 were quantified, the chemical determination, four-dimensional principle component analysis (4D-PCA), and orthogonal hierarchical cluster analysis (2D-HCA) showed a distinctive bioactive component profile of SL from the other two species, and explained the therapeutic potency of SL. As a result, SL has been chosen as a model herb to screen for novel and safe COX-2 selective inhibitors. With systematic uniform experimental designs and statistical modeling, COX-2-MNPs with high magnetic moments and outstanding enzyme activity have been synthesized. Four COX-2-selective compounds, namely, chlorogenic acid, syringin, umbelliferone, and scopoletin, were separated from the herbal extract using fine-tuned fishing protocol and were identified by UPLC-DAD-QTOF-MS. All the four ligands were proved with evidently lower in vitro and in vivo cardiotoxicity than celecoxib, a known selective COX-2 inhibitor. Some of them exerted potent anti-inflammatory activities on cells, and their optimum combination ratios were investigated. Among the ligands, scopoletin showed most evident therapeutic potential in rats with adjuvant-induced arthritis and anterior cruciate ligament transection (ACLT)-induced OA, respectively, by alleviating clinical statuses, immune responses, and joint pathological features. An equal mixture of scopoletin and syringin brought possible synergistic remedial effects on rat OA. Molecular docking results explained the structure-specific enzyme-binding affinities of the ligands; the ligands' inhibition on COX-2 may involve direct interaction as well as upstream signaling pathways. In conclusion, promising candidates of COX-2 selective inibitors, e.g. scopoletin, have been screened and validated on a nanomagnetic ligand fishing platform using COX-2-MNPs from the extract of SL, a most representative snow lotus herb with distinctive chemical composition and outstanding therapeutic efficacies. The quality evaluation strategy of snow lotus herbs combining chemical determination and multidimensional chemometric analysis can be applied in other multi-original herbal medicines. The nanomagnetic ligand fishing platform of compound bio-separation and multi-model bio-evaluation should be equally valuable for uncovering other therapeutic chemicals in different natural sources.

Lau Kit-Man. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 144-164). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgement --- p.v / Declaration --- p.vi / Table of contents --- p.vii / List of Tables --- p.x / List of Figures --- p.xi / List of Abbreviations --- p.xv / Chapter Chapter One: --- General Introduction / Chapter 1.1 --- Tea and Ku-Ding-Cha --- p.1 / Chapter 1.2 --- Ligustrum robustum / Chapter 1.2.1 --- The plant --- p.4 / Chapter 1.2.2 --- Chemical constituents --- p.4 / Chapter 1.2.3 --- Pharmacological activities --- p.4 / Chapter 1.2.4 --- Toxicity --- p.5 / Chapter 1.3 --- Objectives and scope of the project --- p.7 / Chapter Chapter Two: --- Antioxidative effect / Chapter 2.1 --- Introduction / Chapter 2.1.1 --- Oxidants and antioxidants --- p.8 / Chapter 2.1.2 --- In vitro antioxidative tests / Chapter 2.1.2.1 --- PMS-NADH system --- p.19 / Chapter 2.1.2.2 --- Fe3+/ascorbate/H202 system --- p.19 / Chapter 2.1.2.3 --- Red-blood-cell hemolysis model --- p.20 / Chapter 2.2 --- Objectives --- p.22 / Chapter 2.3 --- Materials and Methods / Chapter 2.3.1 --- Materials / Chapter 2.3.1.1 --- Guizhou Ku-Ding-Cha --- p.23 / Chapter 2.3.1.2 --- Other tea leaves --- p.23 / Chapter 2.3.1.3 --- Animals --- p.23 / Chapter 2.3.1.4 --- Chemicals --- p.24 / Chapter 2.3.2 --- Methods / Chapter 2.3.2.1 --- Aqueous extraction of L. robustum and other tea leaves --- p.25 / Chapter 2.3.2.2 --- Ethanol extraction of L. robustum and fraction separations --- p.25 / Chapter 2.3.2.3 --- Activity-guided purification of L. robustum --- p.26 / Chapter 2.3.2.4 --- Assays for testing antioxidative effect / Chapter 2.3.2.4.1 --- PMS-NADH system --- p.28 / Chapter 2.3.2.4.2 --- Fe3+/ascorbate/H202 system --- p.28 / Chapter 2.3.2.4.3 --- Red-blood-cell hemolysis model --- p.29 / Chapter 2.3.2.5 --- Statistical analysis --- p.29 / Chapter 2.4 --- Results / Chapter 2.4.1 --- Ligustrum robustum and other tea leaves --- p.30 / Chapter 2.4.2 --- Ethanol extract of L. robustum --- p.48 / Chapter 2.4.3 --- Water-soluble and water-insoluble fractions --- p.52 / Chapter 2.4.4 --- "Fractions B1, B2 and B3" --- p.56 / Chapter 2.4.5 --- Sub-fractions B2-1 to B2-16 --- p.61 / Chapter 2.4.6 --- Pure compounds --- p.66 / Chapter 2.4.7 --- Changes in antioxidant effects --- p.72 / Chapter 2.5 --- Discussion / Chapter 2.5.1 --- Antioxidant potency of L. robustum --- p.76 / Chapter 2.5.2 --- Effects of extraction methods on antioxidant activities --- p.78 / Chapter 2.5.3 --- Active antioxidant components of L. robustum --- p.78 / Chapter 2.5.4 --- Structure-activity relationship of glycosides and flavonoid --- p.80 / Chapter 2.5.5 --- Antioxidant mechanism of L. robustum --- p.81 / Chapter 2.5.6 --- Prospects for further investigation --- p.82 / Chapter Chapter Three: --- Anti-inflammatory effect / Chapter 3.1 --- Introduction / Chapter 3.1.1 --- Mechanisms and mediators of inflammation --- p.83 / Chapter 3.1.2 --- In vivo anti-inflammatory assays / Chapter 3.1.2.1 --- Acetic acid-induced vascular permeability test --- p.94 / Chapter 3.1.2.2 --- Croton oil-induced ear edema test --- p.94 / Chapter 3.2 --- Objective --- p.96 / Chapter 3.3 --- Materials and Methods / Chapter 3.3.1 --- Materials / Chapter 3.3.1.1 --- Animals --- p.97 / Chapter 3.3.1.2 --- Chemicals --- p.97 / Chapter 3.3.2 --- Methods / Chapter 3.3.2.1 --- Assays for testing anti-inflammatory effect / Chapter 3.3.2.1.1 --- Acetic acid-induced vascular permeability test --- p.98 / Chapter 3.3.2.1.2 --- Croton oil-induced ear edema test --- p.98 / Chapter 3.3.2.2 --- Statistical analysis --- p.99 / Chapter 3.4 --- Results / Chapter 3.4.1 --- Acetic acid-induced vascular permeability test --- p.100 / Chapter 3.4.2 --- Croton oil-induced ear edema test --- p.100 / Chapter 3.5 --- Discussion --- p.103 / Chapter Chapter Four: --- Hepato-protective effect / Chapter 4.1 --- Introduction / Chapter 4.1.1 --- Liver structures and functions --- p.105 / Chapter 4.1.2 --- Carbon tetrachloride-induced liver injury --- p.112 / Chapter 4.1.2.1 --- Mechanisms --- p.112 / Chapter 4.1.2.2 --- Hepatic cytotoxicity --- p.112 / Chapter 4.1.2.3 --- Diagnostic methods / Chapter 4.1.2.3.1 --- Liver weight --- p.114 / Chapter 4.1.2.3.2 --- Lipid peroxidation --- p.114 / Chapter 4.1.2.3.3 --- Serum enzyme levels --- p.114 / Chapter 4.1.2.3.4 --- Histopathological observation --- p.115 / Chapter 4.2 --- Objectives --- p.116 / Chapter 4.3 --- Materials and Methods / Chapter 4.3.1 --- Materials / Chapter 4.3.1.1 --- Animals --- p.117 / Chapter 4.3.1.2 --- Chemicals --- p.117 / Chapter 4.3.2 --- Methods / Chapter 4.3.2.1 --- Carbon tetrachloride-induced acute liver injury --- p.118 / Chapter 4.3.2.2 --- Statistical analysis --- p.120 / Chapter 4.4 --- Results / Chapter 4.4.1 --- Preventive effect / Chapter 4.4.1.1 --- Liver weight --- p.121 / Chapter 4.4.1.2 --- Malondialdehyde content --- p.121 / Chapter 4.4.1.3 --- Serum aminotransferse levels --- p.121 / Chapter 4.4.1.4 --- Histopathological observations --- p.122 / Chapter 4.4.2 --- Curative effect / Chapter 4.4.2.1 --- Liver weight --- p.126 / Chapter 4.4.2.2 --- Malondialdehyde content --- p.126 / Chapter 4.4.2.3 --- Serum aminotransferse levels --- p.126 / Chapter 4.4.2.4 --- Histopathological observations --- p.126 / Chapter 4.5 --- Discussion --- p.130 / Chapter Chapter Five: --- Prospects for product development --- p.134 / Chapter Chapter Six: --- Conclusion --- p.136 / Appendices / Appendix A. Procedure for determining the activity of aspartate aminotransferase (AST) --- p.139 / Appendix B. Procedure for determining the activity of alanine aminotransferase (ALT) --- p.140 / Appendix C. Procedure for preparing a calibration curve for the measurement of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities --- p.141 / Appendix D. Procedure for tissue preparation for light microscopic study --- p.143 / References --- p.144

Lok Chui-Lin. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 142-157). / Abstracts in English and Chinese. / Statement --- p.I / Acknowledgement --- p.II / Abstract --- p.IV / Chinese Abstract (摘要） --- p.VI / Abbreviation --- p.VIII / Table of Contents --- p.XIII / List of Tables --- p.XVII / List of Figures --- p.XVIII / Chapter Chapter One : --- Literature Review --- p.1 / Chapter 1.1 --- The Schistosoma Species --- p.1 / Chapter 1.1.1 --- The Schistosoma Gene Discovery --- p.3 / Chapter 1.1.2 --- Schistosome Transcriptome --- p.4 / Chapter 1.2 --- Schistosomiasis --- p.4 / Chapter 1.2.1 --- Immunopathology of Schistosomiasis --- p.5 / Chapter 1.2.2 --- Diagnosis of Schistosomiasis --- p.7 / Chapter 1.2.3 --- Treatment and Control for Schistosomiasis --- p.7 / Chapter 1.2.4 --- Vaccine Development for Schistosomiasis --- p.8 / Chapter 1.3 --- "The Species, Schistosoma japonicum" --- p.9 / Chapter 1.3.1 --- The Life Cycle of Schistosoma japonicum --- p.10 / Chapter 1.3.1.1 --- "The Egg, Miracidium Phase of the Life Cycle" --- p.12 / Chapter 1.3.1.2 --- Developmental Cycle within Mollusc Host --- p.12 / Chapter 1.3.1.3 --- The Cercaria Phase of Life Cycle --- p.13 / Chapter 1.3.1.4 --- Adult Schistosome in Definitive Host --- p.14 / Chapter 1.4 --- Invasion by Schistosome Cercariae --- p.15 / Chapter 1.5 --- "The Anti-inflammatory Protein, Sml6" --- p.16 / Chapter 1.5.1 --- Discovery of Sm 16 --- p.16 / Chapter 1.5.2 --- Cloning and Expression of Gene-encoding Sm 16 --- p.17 / Chapter 1.5.3 --- Potential Anti-inflammatory Therapy using Sm 16 --- p.18 / Chapter 1.6 --- Innate Immunity and Adaptive Immunity --- p.18 / Chapter 1.6.1 --- Macrophage --- p.18 / Chapter 1.6.2 --- Major Histocompatiblity Complex (MHC) --- p.20 / Chapter 1.6.3 --- Adaptive Immunity to Parasites --- p.20 / Chapter 1.7 --- Inflammation --- p.21 / Chapter 1.7.1 --- Cells of the Inflammatory Process --- p.23 / Chapter 1.7.2 --- Cytokines --- p.24 / Chapter 1.7.2.1 --- Interleukin-1 (IL-1) System --- p.26 / Chapter 1.7.2.2 --- Interferon (IFN) System --- p.27 / Chapter 1.7.3 --- Anti-inflammatory Therapy --- p.28 / Chapter 1.8 --- Aim of Study --- p.29 / Chapter Chapter Two : --- Materials and Methods --- p.30 / Chapter 2.1 --- Materials --- p.30 / Chapter 2.1.1 --- "Cell Lines, Mouse Strain and Bacterial Strains" --- p.30 / Chapter 2.1.2 --- Plasmids --- p.31 / Chapter 2.1.3 --- Chemicals --- p.31 / Chapter 2.1.4 --- "Kits, Nucleic Acids and Reagents" --- p.34 / Chapter 2.1.5 --- Antibodies and Immunoglobins --- p.35 / Chapter 2.1.6 --- Cell Culture Reagents --- p.35 / Chapter 2.1.7 --- Solutions --- p.36 / Chapter 2.1.8 --- Solutions of Reaction Kits --- p.39 / Chapter 2.1.9 --- Enzymes --- p.41 / Chapter 2.1.10 --- Major Equipments and Materials --- p.41 / Chapter 2.1.11 --- Primers --- p.43 / Chapter 2.1.11.1 --- Sequencing and Sj 16 Gene-coding Specific Primers --- p.43 / Chapter 2.1.11.2 --- Primers for Cytokines --- p.43 / Chapter 2.2 --- Methods --- p.45 / Chapter 2.2.1 --- Amplification of Sjl6 cDNA from Schistosoma japonicum Cercariae --- p.45 / Chapter 2.2.1.1 --- Isolation of Cercariae total RNA by Guanidinium Thiocyanate - Cesium Chloride Ultracentrifugation --- p.45 / Chapter 2.2.1.2 --- Reverse Transcription - Polymerase Chain Reaction (RT-PCR) --- p.46 / Chapter 2.2.1.2.1 --- Reverse Transcription (RT) --- p.46 / Chapter 2.2.1.2.2 --- Polymerase Chain Reaction (PCR) --- p.46 / Chapter 2.2.2 --- Cloning and Subcloning of Sj 16 --- p.47 / Chapter 2.2.2.1 --- Preparation of DH5a Competent Cells --- p.47 / Chapter 2.2.2.2 --- Purification of Plasmid DNA --- p.48 / Chapter 2.2.2.3 --- Restriction Enzyme Digestion of DNA --- p.49 / Chapter 2.2.2.4 --- Purification of DNA Fragments from Agarose Gel --- p.50 / Chapter 2.2.2.5 --- Ligation of Purified DNA Fragments --- p.51 / Chapter 2.2.2.6 --- Transformation of Recombinant Plasmid --- p.52 / Chapter 2.2.2.7 --- Selection of Transformed Clones --- p.52 / Chapter 2.2.2.7.1 --- Screening by X-gal and IPTG : a-complementation --- p.52 / Chapter 2.2.2.7.2 --- Screening by Polymerase Chain Reaction --- p.53 / Chapter 2.2.2.8 --- Cycle Sequencing --- p.53 / Chapter 2.2.3 --- Expression of the rSj 16 in Eukaryotic System --- p.55 / Chapter 2.2.3.1 --- Transfection of pSecTag2B/Sj 16 Plasmid into Animal Cells --- p.55 / Chapter 2.2.3.2 --- PCR Screening of Transfected Cells --- p.56 / Chapter 2.2.3.3 --- Analysis of mRNA Transcript by RT-PCR --- p.56 / Chapter 2.2.3.4 --- Concentration of the Condition Medium --- p.57 / Chapter 2.2.3.5 --- Western Blot analysis of rSjl6 Expression --- p.58 / Chapter 2.2.4 --- Expression of rSjl6 in Bacterial System --- p.59 / Chapter 2.2.4.1 --- Transformation of pET30a+/Sjl6 Plasmid into BL21 --- p.59 / Chapter 2.2.4.2 --- Optimization of rSj 16 Expression --- p.60 / Chapter 2.2.4.3 --- Solubility of the rSjl6 --- p.60 / Chapter 2.2.4.4 --- Estimation of rSj 16 Concentration --- p.62 / Chapter 2.2.4.5 --- Western Blot Analysis of rSj 16 --- p.62 / Chapter 2.2.5 --- Recombinant Protein Purification --- p.63 / Chapter 2.2.5.1 --- Affinity Chromatography of Recombinant Protein --- p.63 / Chapter 2.2.5.2 --- Dialysis of Eluted Recombinant Protein in PBS --- p.64 / Chapter 2.2.5.3 --- Estimation of Recombinant Protein Concentration --- p.65 / Chapter 2.2.6 --- Demonstrate the Anti-inflammatory Activity of rSj 16 --- p.65 / Chapter 2.2.6.1 --- Thioglycollate Induced Macrophage Recruitment --- p.65 / Chapter 2.2.6.2 --- Cytospin and Hemacolor Staining of PECs --- p.66 / Chapter 2.2.6.3 --- FACS Analysis of PECs --- p.67 / Chapter 2.2.6.4 --- Isolation of total RNA by TRIZOL Reagent --- p.67 / Chapter 2.2.7 --- Immunogenicity and Antigenicity of rSjl6 --- p.68 / Chapter 2.2.7.1 --- Western Blot of rSjl6 with Schistosoma japonicum infected rabbit serum --- p.69 / Chapter 2.2.7.2 --- Preparation of Anti-Sj 16 Serum --- p.69 / Chapter 2.2.7.3 --- Western Blot of rSjl6 with immunized mice serum --- p.70 / Chapter 2.2.8 --- FACS analysis of MHC (I) Expression --- p.71 / Chapter 2.2.9 --- Anti-proliferative Assay using BrdU Kit --- p.72 / Chapter Chapter Three : --- Results --- p.73 / Chapter 3.1 --- Amplification of Sj 16 cDNA from Schistosoma japonicum Cercariae total RNA --- p.73 / Chapter 3.2 --- Construction of pBluescript II SK(-) / Sjl6 --- p.75 / Chapter 3.3 --- Analysis of Sj 16 Nucleotide and Amino Acid Sequence --- p.78 / Chapter 3.3.1 --- Blastn Search Analysis --- p.80 / Chapter 3.3.2 --- Blastx Search Analysis --- p.82 / Chapter 3.3.3 --- Structural Analysis --- p.84 / Chapter 3.4 --- Subcloning of Sjl6 cDNA into pET30a+ and pSecTag2B Expression Vector --- p.88 / Chapter 3.5 --- Expression of the rSj 16 --- p.92 / Chapter 3.5.1 --- Animal Cell Expression --- p.92 / Chapter 3.5.1.1 --- Analysis of mRNA Transcript by RT-PCR --- p.93 / Chapter 3.5.1.2 --- Western Blot of Condition Medium --- p.95 / Chapter 3.5.2 --- Bacterial Cell Expression --- p.97 / Chapter 3.5.2.1 --- Optimization of rSjl6 Expression --- p.97 / Chapter 3.5.2.2 --- Estimation of rSjl6 Concentration --- p.98 / Chapter 3.5.2.3 --- Solubility of rSj16 --- p.99 / Chapter 3.5.2.4 --- Western Blot Analysis of rSjl6 --- p.100 / Chapter 3.6 --- Purification of Recombinant Protein --- p.101 / Chapter 3.6.1 --- Purification of rSj16 --- p.101 / Chapter 3.6.2 --- Purification of rSjCa8 --- p.104 / Chapter 3.7 --- Anti-inflammatory Activity of rSj 16 --- p.107 / Chapter 3.7.1 --- Analysis of PECs in Thioglycollate Induced Inflammation --- p.107 / Chapter 3.7.2 --- Hemacolor Staining of PECs --- p.110 / Chapter 3.7.3 --- FACS Analysis of PECs --- p.110 / Chapter 3.7.4 --- RT-PCR of RNA Isolated from PECs --- p.115 / Chapter 3.8 --- Immunogenicity and Antigenicity of rSjl6 --- p.117 / Chapter 3.8.1 --- Immunogenicity of rSj 16 --- p.117 / Chapter 3.8.2 --- Antigenicity of rSj16 --- p.117 / Chapter 3.9 --- Inhibitory Effect of rSj 16 on rMuIFN-a4 Induced Up-regulation of MHC(I) Expression --- p.120 / Chapter 3.9.1 --- Time Course of rMuIFN-α4 Induced Up-regulation of MHC(I) Expression --- p.120 / Chapter 3.9.2 --- Inhibitory Effect of rSjl6 on rMuIFN-α4 Induced MHC (I) Up-regulation --- p.120 / Chapter 3.9.3 --- "Anti-proliferation Effect of rMuIFN-a4, rSj 16 and rSjCa 8" --- p.124 / Chapter 3.9.4 --- Effect of Signal Transduction Inhibitors on rMuIFN-a4 Induced MHC (I) Up-regulation --- p.126 / Chapter Chapter Four : --- Discussion and Conclusion --- p.129 / Chapter 4.1 --- Discussion --- p.129 / Chapter 4.1.1 --- Overview --- p.129 / Chapter 4.1.2 --- Molecular and Structural Analysis of rSj 16 --- p.130 / Chapter 4.1.3 --- Relationship between Sml6 and Sjl6 --- p.131 / Chapter 4.1.4 --- Anti-inflammatory Activity of rSj 16 --- p.132 / Chapter 4.1.5 --- Immunogenicity and Antigenicity of rSjl6 --- p.137 / Chapter 4.1.6 --- Inhibitory Effect of rSjl6 on rMuIFN-a4 Induced Up-regulation of MHC (I) Expression --- p.138 / Chapter 4.1.7 --- Relation between Sj 16 and the Innate Immune System --- p.139 / Chapter 4.1.8 --- Further Study and Significance --- p.140 / Chapter 4.2 --- Conclusion --- p.141 / References --- p.142

Thesis (M.S.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains viii, 51 p. : ill. Includes abstract. Includes bibliographical references (p. 39-42).

Thesis (M.S.)--West Virginia University, 2005. / Title from document title page. Document formatted into pages; contains viii, 59 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 33-38).

Thesis (M.S.)--University of Louisville, 1997. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Louisville, 1997. / Includes bibliographical references.

Thesis (Ph. D.)--University of Oklahoma. / Bibliography: leaves 168-181.

published_or_final_version / abstract / Medicine / Doctoral / Doctor of Philosophy

Our hypothesis is that the polyamine biosynthetic pathway, a pathway essential in many cellular functions, is modulated by NSAIDs and that this is, at least in part, how NSAID chemoprevention is mediated. An <i>in vitro </i>model of colorectal cancer was used: two cell lines one of which is COX positive and one COX negative to determine the effects of a range of selective and non-selective NSAIDs on various reactions within the polyamine pathway.  NSAIDs are cytotoxic to colorectal cancer cells regardless of their COX expression.  NSAID-mediated inhibition of cell growth is accompanied by inhibition of ODC activity, partial depletion of polyamine concentrations and up-regulation of polyamine catabolism. In order to investigate the importance of polyamine metabolism, a specific polyamine inhibitor α-difluoromethylornithine (DFMO) was used in combination with the NSAIDs.  DFMO <i>per se </i>is not toxic to cells and it does not enhance NSAID mediated toxicity.  DFMO in combination with the NSAIDs did cause increased catabolic activity and more sustained polyamine depletion than either alone, however no additional decrease in ODC activity was observed.  This suggests that NSAID toxicity is not enhanced by DFMO in this <i>in vitro </i>model. Analysis of the mode of death indicated that the NSAIDs caused apoptotic cell death, confirmed through biochemical and morphological studies and that the NSAIDs affected gene expression of key enzymes in the polyamine biosynthetic pathway. Our findings suggest that modulation of the polyamine pathway by NSAIDs is at least part of the mechanism of action involved in cancer chemoprevention. Therefore modulation of the polyamine pathway may be useful for design of new chemopreventative drugs.