This thesis aims to develop a new and inexpensive synthetic route to the anti-cancer drug etoposide (6) via 4'-demethylpodophyllotoxin (4) or 4'-demethylepipodophyllotoxin (5) involving the oxidative coupling of a dibenzylbutanolide catalyzed by a cell-free extract (CFE) from plant cell culture. This step was studied in depth using the Catharanthus roseus CFE-catalyzed biotransformation of frans-2-(3,5-dimethoxy-4-hydroxybenzyl)-3-(3-hydroxy-4-methoxybenzyl)butanolide (58) to 1-(3,5-dimethoxy-4-hydroxyphenyl)-6-hydroxy-3-hydroxymethyl-7-methoxy-1,2,3,4-tetrahydro-2-naphthoic acid γ lactone (59) as a model. The optimum values of reaction pH, enzyme:substrate ratio and co-factonsubstrate ratio were determined. The butanolide 58 was synthesized by a route involving the Stobbe condensation of 3-benzyloxy-4-methoxybenzaldehyde with dimethylsuccinate to yield 2-(3-benzyloxy-4-methoxybenzylidene)butanedioic acid 1-methyl ester (69). Hydrogenation of 69 to 2-(3-benzyloxy-4-methoxybenzyl)butanedioic acid 1-methyl ester (70) followed by reductive lactonization afforded 3-(3-benzytoxy-4-methoxybenzyl)butanolide (71). Alkylation of 71 with 4-benzyloxy-a-bromo-3,5-dimethoxytoluene (72) gave frans-2-(4-benzyloxy-3,5-dimethoxybenzyl)-3-(3-benzyloxy-4-methoxybenzyl)butanolide (73) which was then converted to the butanolide 58 by catalytic hydrogenolysis. In order to investigate the effect of different aromatic substituents on the oxidative coupling of butanolides, C. roseus CFE-catalyzed biotransformations of frans-2-(3,5-dimethoxy-4-hydroxybenzyl)-3-(3,4-methylenedioxybenzyl)butanolide (74) and frans-2-(3,5-dimethoxy-4-hydroxybenzyl)-3-(3,4-dihydroxy-a-hydroxybenzyl)butanolide (94) were also performed. The biotransformation of 74 gave 2-(3,5-dimethoxy-4-hydroxybenzylidene)-3-(3,4-methylenedioxybenzyl)butanoiide (76) as the sole isolated product. A pathway involving oxidative demethylatton is proposed to account for the balance of the unrecovered material. The butanolide 94, a potential precursor to etoposide, was prepared from piperonal. The lithium anion of 1-bis(phenylthio)methyl-3,4-methylenedioxybenzene (97) and the bromide 72 were added consecutively to but-2-en-4-olide to afford frans-2-(4-benzyloxy-3,5-dimethoxybenzyl)-3-(3,4-methylenedioxy-α,α-bis(phenylthio)benzyl)butanolide (96). A synthetic sequence involving the oxidation of 96 to frans-2-(4-benzyloxy-3,5-dimethoxybenzyl)-3-(3,4-methylenedioxybenzoyl)-butanolide (100), reduction to frans-2-(4-benzyloxy-3,5-dimethoxybenzyl)-3-(α-hydroxy-3,4-methylenedioxybenzyl)butanolide (109) and cleavage of the methylenedioxy and benzyl protecting groups gave the catechol 94. Unfortunately, the CFE-catalyzed oxidation of 94, following treatment with sodium borohydride, yielded 4-(3,4-dihydroxyphenyl)-5,7-dimethoxy-6-hydroxy-2-hydroxymethyl-1,2,3,4-tetrahydro-2-naphthoic acid γ lactone (103) as the sole isolated product. [Formulas omitted] / Science, Faculty of / Chemistry, Department of / Graduate

No description available.

Background: ICG-001, an antagonist of CBP (CREB-binding protein), has been demonstrated to exert anti-tumor activity via the modulation of the Wnt signalling pathway. It has previously been demonstrated that miRNAs play an important role in ICG-001-mediated tumor suppression. In the present study, the role of miRNA-134 and 1-integrin in ICG-001-mediated anti-tumor activity in nasopharyngeal carcinoma (NPC) was examined. Methods: NPC cell lines including C666-1, HONE-1 and HK-1 were used in this study. RT-PCR and Western blot were used to study the expression of miRNA-134 and the protein expression of the target proteins, respectively. Confocal microscopy was used to analyse the subcellular localization of 1-integrin. In the functional studies, in vitro endothelial adhesion assay and in vivo nude mice model were used to evaluate the adhesion and migration of ICG-001-treated NPC cells in animals, respectively. Results: ICG-001 was found to up-regulate the expression of miRNA-134 and down-regulate 1-integrin in NPC cells. The effect was accompanied with the inhibition of the adhesion of NPC cells to lung endothelial cells. In addition, over-expression of miRNA-134 would down-regulate the expression of 1-integrin. Results from 1-integrin 3'UTR Renilla luciferase reporter assay confirmed that 1-integrin is a target of miRNA-134 in NPC cells. In the animal study, the ability of ICG-001-pretreated NPC cells or stable miRNA-134 expressing NPC cells to migrate to the mouse lung was greatly reduced. Conclusion: The CBP antagonist ICG-001 may further be developed as an anti-tumor agent for the treatment of nasopharyngeal carcinoma

No description available.

No description available.

Hung Sau Ling. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1994. / Includes bibliographical references (leaves 131-137). / Table of Contents --- p.1 / Acknowledgements --- p.V / Abbreviations --- p.VI / Aim of investigation --- p.IX / Abstract --- p.XI / Chapter Chapter 1 --- General Introduction --- p.1 / Chapter 1.1 --- Cancer Chemotherapy --- p.2 / Chapter 1.2 --- Plants as sources of useful drugs --- p.4 / Chapter 1.3 --- Potent antitumor compounds found in Goniothalamus giganteus --- p.7 / Chapter 1.4 --- Brief introduction of GONIOTRIOL --- p.8 / Chapter 1.5 --- The study on the antitumor activities of the antitumor compounds --- p.9 / Chapter 1.6 --- Biochemistry study of the anticancer agents --- p.10 / Chapter Chapter 2 --- Materials and Methods --- p.18 / Chapter 2.1 --- Materials --- p.19 / Chapter 2.1.1 --- Animals --- p.19 / Chapter 2.1.2 --- "Buffers, Culture Media and Chemicals" --- p.19 / Chapter 2.1.3 --- Cell lines --- p.20 / Chapter 2.1.4 --- Dye solutions --- p.21 / Chapter 2.1.5 --- Reagents and buffers for Agarose gel --- p.21 / Chapter 2.1.6 --- Synthetic goniotriol and its derivatives --- p.21 / Chapter 2.2 --- Methods --- p.23 / Chapter 2.2.1 --- Radioactive Precursor Incorporation Assays --- p.23 / Chapter 2.2.2 --- MTT assay --- p.24 / Chapter 2.2.3 --- Neutral Red assay --- p.24 / Chapter 2.2.4 --- Isolation and preparation of cells --- p.25 / Chapter 2.2.5 --- Assay for the solvent effect --- p.25 / Chapter 2.2.6 --- Assay for the in vitro antitumor activity THC88 on different cell lines --- p.27 / Chapter 2.2.7 --- Assay of the effect of THC86 on solid sarcoma Scl80 in vivo --- p.28 / Chapter 2.2.8 --- Assay of the effect of THC86 on peritoneal Scl80 in vivo --- p.28 / Chapter 2.2.9 --- Assay of the effect of THC89 on peritoneal EAT in vivo --- p.28 / Chapter 2.2.10 --- Assay of synthetic compound (THC89 and THC87) on the mitogenic activity of spleen lymphocytes --- p.29 / Chapter 2.2.11 --- Assay of synthetic compound (THC87) on the proliferation of murine bone marrow cells from compound- treated mice --- p.30 / Chapter 2.2.12 --- "Assay of synthetic compounds (Ml, P51 and P1) on nonmalignant cell-line" --- p.31 / Chapter 2.2.13 --- Assay of antitumor activity of synthetic compound (THC86)on PU5-1.8 --- p.31 / Chapter 2.2.14 --- Assay of the cytocidal effect of THC86 --- p.32 / Chapter 2.2.15 --- "Assay on the effect of THC86 on the synthesis of DNA, RNA and protein" --- p.32 / Chapter 2.2.16 --- Direct DNA cleavage by THC86 --- p.33 / Chapter 2.2.17 --- DNA fragmentation assay / Chapter 2.2.18 --- Assay of the effect of the synthetic compound (THC86) on different growth fraction of the cells / Chapter 2.2.19 --- Mitosis Study / Chapter 2.2.20 --- Assay for the stability of the synthetic compounds / Chapter Chapter 3 --- Structure / activity relationship of the synthetic compounds --- p.36 / Chapter 3.1 --- Results --- p.37 / Chapter 3.1.1 --- In vitro antitumor activity of the synthetic compounds --- p.37 / Chapter 3.2 --- Discussion --- p.45 / Chapter Chapter 4 --- Antitumor activities of the synthetic compounds --- p.63 / Chapter 4.1 --- Results --- p.64 / Chapter 4.1.1 --- Solvent effect in the screening process --- p.64 / Chapter 4.1.2 --- The effect of the synthetic compound (THC88) on different cell lines --- p.69 / Chapter 4.1.3 --- In vivo anti-tumor activities of the synthetic compounds --- p.71 / Chapter 4.1.3a --- Effect of THC86 on solid sarcoma Sc180 in vivo --- p.71 / Chapter 4.1.3b --- Effect of THC86 on peritoneal Scl80 in vivo --- p.71 / Chapter 4.1.3c --- Effect of THC89 on peritoneal EAT in vivo --- p.72 / Chapter 4.1.4 --- Cytotoxic effect of the tested compounds on normal cells --- p.77 / Chapter 4.1.4a --- Cytotoxic effect of THC89 on normal splenocytes in vitro --- p.77 / Chapter 4.1.4b --- Effect of THC87 on the proliferation of splenocytes --- p.77 / Chapter 4.1.4c --- Effect of THC87 on the proliferation of murine bone marrow cells --- p.78 / Chapter 4.1.4d --- Cytotoxic effect on non-malignant cell-line BALB/c 3T3/A31 --- p.78 / Chapter 4.2 --- Discussion --- p.85 / Chapter Chapter 5 --- The study on the antiproliferative mechanisms of the synthetic compounds --- p.88 / Chapter 5.1 --- Results --- p.89 / Chapter 5.1.1 --- "Effect of the synthetic compounds on Cell Growth, DNA, RNA and Protein" --- p.89 / Chapter 5.1.1a --- Effect of THC86 on PU5-1.8 (macrophage-like tumor) --- p.89 / Chapter 5.1.1b --- Cytocidal effect of THC86 on EAT --- p.89 / Chapter 5.1.1c --- "Effect of the synthetic compounds on synthesis of DNA, RNA and protein" --- p.90 / Chapter 5.1.2 --- Study of the synthetic compounds on the interactions of DNA --- p.101 / Chapter 5.1.2a --- DNA cleavage assay --- p.101 / Chapter 5.1.2b --- DNA fragmentation assay --- p.101 / Chapter 5.1.3 --- Effect of the synthetic compounds on different growth fraction of the cells --- p.104 / Chapter 5.1.4 --- Mitosis study of the synthetic compounds --- p.106 / Chapter 5.1.5 --- Investigation of the stability of the synthetic compounds in culture medium --- p.112 / Chapter 5.2 --- Discussion --- p.117 / Chapter Chapter 6 --- General Discussion --- p.122 / References --- p.131

Diss. (sammanfattning) Stockholm : Karol. inst., 2004. / Härtill 5 uppsatser.

Novel mitosenes substituted at the 6-position were synthesized for antineoplastic screening. More than 26 new compounds were made by two synthetic routes. A Nenitzescu-type synthesis provided ethyl 1-acetoxy-2,3-dihydro-5,8-dione-7-methoxy-1H-pyrrolo{1,2-a}indole-9-carboxylate. However, selective reduction of this ester could not be achieved satisfactorily. A more practical route via annelation of a commercially available indole was successful in completing the planned scheme of 6-substituted mitosene congeners. The third ring (pyrrolidine) was added by condensation of ethyl acrylate with ethyl 5-methoxyindole-2-carboxylate. After decarboxylation at position 2, the ketone at position 1 was reduced and acetylated. Then the carbon at the 9 position was introduced by Vilsmeier-Haack formylation and the quinone moiety was synthesized via a nitration, reduction, and oxidation sequence. Subsequently, the aldehyde was most satisfactorily reduced to an alcohol with sodium borohydride and the quinone was regenerated with Fremy's salt. 1-acetoxy-6-desmethyl-7-methoxymitosene was made by forming a carbamate at position 9 by treatment of the 9-alcohol with phenyl chloroformate and displacing the phenoxy group with ammonia. Other 1,6,7-substituted mitosene congeners were made using N-methylcarbamate formation via methyl isocyanate and the 9-alcohol. The 6-chloro and 6-bromo analogs were formed by treatment of the 6-H congener, 1-acetoxy-2,3-dihydro-5,8-dioxo-9-(hydroxymethyl)-7-methoxy-1H-pyrrolo{1,2-a}indole methylcarbamate, with the desired halogen in acetic acid and sodium acetate. The 7-methoxy group could be displaced by ammonia for the 6-bromo compound and by pyrrolidine for the 6-H compound to form respectively the 7-amino-6-bromo and 7-pyrrolidino-6-H 1-acetoxy-2,3-dihydro-5,8-dioxo-9-(hydroxymethyl)-1H-pyrrolo{1,2-a}indole methylcarbamates. The 6-methyl analog (1-acetoxy-7-methoxy-N-methyl-carbamoylmitosene) was made from a previously synthesized precursor. Attempted syntheses of the 6-azido and 6-amino analogs by displacing the 6-bromo substituent with sodium azide were met by gross rearrangement of the resulting adducts. Preliminary antitumor screening against P388 leukemia in mice showed these analogs to be too inactive for use as antineoplastic agents. The 6-methyl substituent was shown to be most potent in bacteriophage induction in E. coli for this series of 6-substituted mitosene analogs.

published_or_final_version / Dentistry / Doctoral / Doctor of Philosophy

published_or_final_version / abstract / Anatomy / Master / Master of Philosophy