Diss. (sammanfattning) Uppsala : Univ., 2002. / Härtill 4 uppsatser.

This dissertation focuses on chemical and biological evaluation of diazeniumdiolate based nitrogen oxide releasing prodrugs. Three projects are described. i. Synthesis and biological evaluation of a series of new nitroxyl (HNO) releasing non-steroidal antiinflammatory drugs (NSAIDs) and comparison to related nitric oxide (NO) releasing NSAIDs A series of HNO releasing isopropylamine-based diazeniumdiolate adducts of NSAIDs and the NO releasing diethylamine diazeniumdiolate counterpart were synthesized. The aspirin derivatives were evaluated for antiinflammatory, cardioprotective and anticancer effects. Both prodrugs demonstrated similar antiinflammatory properties to aspirin but significantly lower gastrointestinal ulceration, which is a common side effect of aspirin. The HNO adduct also improved cardiac contractility. The chemotherapeutic potential of the prodrugs was assessed in vitro and in vivo. Both the prodrugs inhibited growth of cultured carcinoma cells without inducing cytotoxicity towards non-tumorogenic cell lines. The higher cytotoxicity of the HNO adduct was in part due to increased production of reactive nitrogen and oxygen species leading to oxidative damage to DNA, inhibition of glyceraldehydes-3-phosphate dehydrogenase and upregulation of signaling pathways leading to caspase-3 mediated induction of apoptosis. The NO adduct is a promising candidate for reduction of metastasis by increasing E-cadherin levels, which influences cellular adhesion. Both derivatives showed significantly reduced angiogenesis in cultured cells and tumor volume in nude mice. ii. Synthesis and characterization of primary amine based cyclic amine diazeniumdiolates and comparison to their acetoxy methyl ester derivatives. A series of HNO releasing cyclic amine diazeniumdiolates were synthesized to expand upon the few examples of primary amine diazeniumdiolates. An ester derivative of cyclopentylamine NONOate was also synthesized, to increase decomposition half-life and to improve HNO production and better cellular uptake. This modification increased its cytotoxicity compared to ionic NONOates. iii. Evaluation of mechanism of action of JS-K. JS-K (O²-(2,4-dinitrophenyl)-1-[(4-ethoxycarbonyl)-piperazin-1-yl]-diazeniumdiolate) has previously been found to be highly cytotoxic in many cancer cell lines compared to ionic diazeniumdiolates. Thus, the role of NO in cytotoxicity of JS-K was explored. A low intracellular NO flux in combination with a lack of any effect on cyclic guanosine monophosphate (cGMP) dependent pathway suggests that NO is not directly responsible for the cytotoxicity of JS-K.

Diss. (sammanfattning) Uppsala : Univ., 2003. / Härtill 4 uppsatser.

Diss. (sammanfattning) Göteborg : Göteborgs universitet , 2008. / Härtill 5 uppsatser.

Thesis (Ph. D.)--Ohio State University, 2006. / Available online via OhioLINK's ETD Center; full text release delayed at author's request until 2007 Mar 3

Thesis (Ph.D.) - University of Queensland, 2006. / Includes bibliography.

Thesis (Ph. D.)--School of Pharmacy. University of Missouri--Kansas City, 2004. / "A dissertation in pharmacology and pharmaceutical sciences." Advisor: Orisa J. Igwe. Typescript. Vita. Title from "catalog record" of the print edition Description based on contents viewed Feb. 27, 2006. Includes bibliographical references (leaves 166-180). Online version of the print edition.

Thesis (M.S. in Cancer Biology)--Vanderbilt University, Aug. 2007. / Title from title screen. Includes bibliographical references.

Colorectal cancer (CRC) is a common disease with significant morbidity and mortality. In spite of significant advances in understanding the molecular signaling in this disorder, unanswered questions remain. Cyclooxygenase-2 (COX-2) and β-catenin have established roles in colorectal carcinogenesis, with both being upregulated early in the disease course. The role of peroxisome proliferator-activated receptor γ (PPARγ) is less clear, but has been shown to be downregulated in colon cancer models. Butyrate, a short chain fatty acid, produced by colon microbiota and transported into the colonocyte by transporter proteins, appears to be important in early carcinogenesis. The butyrate concentration is reduced in CRC and so are its transporters. Interleukin-17 (IL-17) plays a role in colitis-associated colorectal cancer (CAC), but its function in sporadic CRC is less clear. Similarly, Protein kinase C (PKC) has proven involvement in many solid tumours, including CRC, but its exact mechanistic role is still speculative. AIM: To investigate the role and possible signaling pathways of the major role players, β-catenin, COX-2 and PPARγ in early CRC. Further, to elucidate the mechanistic pathways of butyrate and its transporters, IL-17 and PKC in CRC. METHOD: Informed consent was obtained for all patients. Patients were recruited in various disease categories, including normal, irritable bowel syndrome (IBS), inflammatory bowel disease (IBD) and CRC. Colon biopsy specimens were obtained during colonoscopy and used for immunohistochemistry (IHC) and gene expression analysis of the above genes by quantitative polymerase chain reaction (qPCR). RESULTS: β-catenin mRNA and protein expression was increased in CRC and the IBD groups compared to the normal group, while it was reduced in the IBS groups. COX-2 mRNA expression showed a steady increase from normal, through IBS, IBD and CRC groups to a statistically significant degree. The COX-2 protein expression, however, did not match the mRNA expression with increased COX-2 protein expression in normal and IBS groups and reduced expression in IBD and CRC groups. PPARγ mRNA expression was unchanged in IBD and CRC groups, but significantly increased in the IBS group compared to normal. Butyrate transporter, SLC16A1 mRNA was significantly reduced in CRC, but also in the IBS groups, which was unexpected. In the IBD group, SLC16A1 mRNA was unchanged in Crohn’s disease (CD) but significantly reduced in ulcerative colitis (UC). Similarly, SLC5A8 mRNA expression was significantly reduced in the CRC as well as the IBS groups. In the IBD groups, SLC5A8 was unchanged in UC but significantly increased in CD. IL-17 mRNA expression was significantly reduced in CRC and IBS groups, but unchanged in the IBD groups. PKCε mRNA was significantly increased in CRC as expected. In the IBD groups, PKCε mRNA was unchanged in CD but significantly increased in UC. In the IBS groups, PKCε mRNA in constipation –IBS (C-IBS) was significantly reduced, but unchanged in diarrhoea – IBS (D-IBS). CONCLUSIONS: β-catenin mRNA and protein expression was increased in CRC and the CRC promoting IBD groups. COX-2 protein expression was incongruent with the COX-2 mRNA expression and this may reflect homeostatic control mechanisms. High COX-2 mRNA expression in CRC and CRC promoting IBD groups may be a secondary phenomenon reflecting the inflammatory milieu, rather than a true carcinogenesis-related event. PPARγ does not appear to play a central role in early colon carcinogenesis, in spite of available literature suggesting otherwise. Butyrate transporters showed inconsistent results and for now no firm conclusions can be drawn from this. IL-17 may play a role in CAC as confirmed in this and other studies, but its role in sporadic CRC is tenuous and requires further investigation. Likewise for PKCε, upregulation is associated with increased tumourigenecity as shown in this study, however, the mechanistic pathway(s) involved is still speculative and requires further study.

Chronic kidney disease is defined as the appearance of kidney functional or structural injury. Cyclooxygenase and prostaglandin E2 have been implicated in the pathogenesis of diabetic nephropathy, the leading cause of chronic kidney disease. Beneficial in certain settings, inhibition of the cyclooxygenase pathway can however be detrimental in patients with compromised cardiac or renal function. Moreover, the quest for new therapies to treat diabetic nephropathy is hampered by the lack of appropriate rodent models. This doctoral thesis is a culmination of three studies, the first to determine the role of the prostaglandin E2 EP1 receptor in diabetic nephropathy, the second to elucidate the vascular prostaglandin E2 EP4 receptor’s role in hypertension and lastly to establish and characterise a novel mouse model of diabetic nephropathy. The goal being to uncover new therapeutic avenues for the treatment of CKD, its causes and/or complications.