No description available.

No description available.

No description available.

Une série de soixante deux molécules basées sur le motof 8-hydroxyquinoléine a été synthétisée pour évaluer les effets de changements structuraux sur l'activité antitumorale et comprendre les mécanismes d'action mises en jeu. L'étude a été réalisée sur un large panel de lignées cellulaires cancéreuses dont des gliomes, des carcinomes et des mélanomes. Des expériences in vivo impliquant des xénogreffes sur des souris transgéniques ont été réalisées pour confirmer les effets anticancéreux observés in vitro. De plus, une étude complète sur la cible biologique a été réalisée a été menée sur les récepteurs PPAR, la voie des caspases, l'activité ptotéosomique et l'assemblage des tubulines. Les analogues basés sur la 8-hydroxyquinoléine peuvent représenter une voie thérapeutique nouvelle et inédite dans le traitement anticancéreux avec des mécanismes d'action impliquant les thiols de certaines protéines / A series of sixty two molecules based on 8-hydroxyquinoline were synthesized to evaluate the effects of structural changes on antitumor activity and understand their mechanism of action. The studies were performed on a wide variety of cancer cell lines within glioma, carcinoma and melanoma models. In vivo experiments on mice brain wenagrafted by glioblastoma cells had been proceed to confirmate in vitro anti-cancer effects. Moreover a complete investigation about the biological target have been realised on PPAR receptors, caspase pathway, proteosomal activity and tubulin assembly. The described analogues could represent new promising anti-cancer candidates with specific action mechanisms, targeting accessible thiols from specific proteins and inducing potent anticancer effects.

Several types of insect cuticle contain enzymes catalyzing the formation ofof adducts between N-acetyldopamine (NADA) and N-acetylhistidine (NAH). Two such adducts, NAH-NADA-I and NAH NADA-II, have been isolated and their structures determined. In one of the adducts the link connecting the two residues occurs between the I-position (ß-position) in the NADA side chain and the 1-N atom (τ-N) in the imidazole ring of histidine. Diphenoloxidase activity alone is not sufficient for formation of this adduct, whereas extracts containing both diphenoloxidase and o-quinone-p-quinone methide isomerase activities catalyze the coupling reaction. The adduct consists of a mixture of two diastereomers and they are presumably formed by spontaneous reaction between enzymatically produced NADA-p-quinone methide and N-acetylhistidine. The other adduct has been identified as a ring addition product of N-acetylhistidine and NADA. In contrast to the former adduct it can be formed by incubation of the two substrates with mushroom tyrosinase alone. An adduct between N-acetylhistidine and the benzodioxan-type NADA-dimer is produced in vitro, when the N-acetylhistidine-NADA adduct is incubated with NADA and locust cuticle containing a 1,2-dehydro-NADA generating enzyme system. Trimeric NADA-polymerization products of the substituted benzodioxan-type have been obtained from in vivo sclerotized locust cuticle, confirming the ability of cuticle to produce NADA-oligomers. The results indicate that some insect cuticles contain enzymes promoting linkage of oxidized NADA to histidine residues. It is suggested that histidine residues in the cuticular proteins can serve as acceptors for oxidized NADA and that further addition of NADA-residues to the phenolic groups of bound NADA can occur, resulting in formation of protein-linked NADA-oligomers. The coupling reactions identified may be an important step in natural cuticular sclerotization.

The development of reversible and irreversible inhibitors of steroid sulfatase (STS) and protein tyrosine phosphatase 1B (PTP1B) is reported herein. STS belongs to to the aryl sulfatase family of enzymes that have roles in diverse processes such as hormone regulation, cellular degradation, bone and cartilage development, intracellular communication, and signalling pathways. STS catalyzes the desulfation of sulfated steroids which are the storage forms of many steroids such as the female hormone estrone. Its crucial role in the regulation of estrogen levels has made it a therapeutic target for the treatment of estrogen-dependent cancers. Estrone sulfate derivatives bearing 2- and 4-mono- and difluoromethyl substitutions were examined as quinone methide-generating suicide inhibitors of STS with the goal of developing these small molecules as activity-based probes for proteomic profiling of sulfatases. Kinetic studies suggest that inhibition by the monofluoro derivatives is a result of a quinone methide intermediate that reacts with active-site nucleophiles. However, the main inhibition pathway of the 4-difluoromethyl derivative involved an unexpected process in which initially formed quinone methide diffuses from the active site and decomposes to an aldehyde in solution which then acts as a potent, almost irreversible STS inhibitor. This is the first example where this class of inactivator functions by in situ generation of an aldehyde. 6- and 8-mono- and difluoromethyl coumarin derivatives were also examined as quinone methide-generating suicide inhibitors of STS. The 6-monofluoromethyl derivative acted as a classic suicide inhibitor. The partition ratio of this compound was found to be very large indicating that this class of compounds is not likely suitable as an activity-based probe for proteomic profiling of sulfatases. Boronic acids derived from steroid and coumarin platforms were also examined as STS inhibitors with the goal of improving our understanding of substrate binding specificity of STS. Inhibition constants in the high nanomolar to low micromolar range were observed for the steroidal derivatives. The coumarin derivatives were poor inhibitors. These results suggest that the boronic acid moiety must be attached to a platform very closely resembling a natural substrate in order for it to impart a beneficial effect on binding affinity compared to its phenolic analog. The mode of inhibition observed was reversible and kinetic properties corresponding to the mechanism for slow-binding inhibitors were not observed. PTP1B catalyzes the dephosphorylation of phosphotyrosine residues in the insulin receptor kinase and is a key enzyme in the down regulation of insulin signaling. Inhibitors of PTP1B are considered to have potential as therapeutics for treating type II diabetes mellitus. The difluoromethylenesulfonic (DFMS) acid group, one of the best monoanionic phosphotyrosine mimics reported in the literature, was examined as a phosphotyrosine (pTyr) mimic in a non-peptidyl platform for PTP1B inhibition. The DFMS-bearing inhibitor was found to be an approximately 1000-fold poorer inhibitor than its phosphorus analogue. It was also found that the fluorines in the DFMS inhibitor contributed little to inhibitory potency. In addition, [sulfonamido(difluoromethyl)]-phenylalanine (F2Smp) was examined as a neutral pTyr mimic in commonly used hexapeptide and tripeptide platforms. F2Smp was found to be a poor pTyr mimic. These inhibition studies also revealed that the tripeptide platform is not suitable for assessing pTyr mimics for PTP1B inhibition. Taken together, the kinetic data on the inhibition of STS and PTP1B provide valuable information relevant for future design of inhibitors of these two therapeutic targets.

The development of reversible and irreversible inhibitors of steroid sulfatase (STS) and protein tyrosine phosphatase 1B (PTP1B) is reported herein. STS belongs to to the aryl sulfatase family of enzymes that have roles in diverse processes such as hormone regulation, cellular degradation, bone and cartilage development, intracellular communication, and signalling pathways. STS catalyzes the desulfation of sulfated steroids which are the storage forms of many steroids such as the female hormone estrone. Its crucial role in the regulation of estrogen levels has made it a therapeutic target for the treatment of estrogen-dependent cancers. Estrone sulfate derivatives bearing 2- and 4-mono- and difluoromethyl substitutions were examined as quinone methide-generating suicide inhibitors of STS with the goal of developing these small molecules as activity-based probes for proteomic profiling of sulfatases. Kinetic studies suggest that inhibition by the monofluoro derivatives is a result of a quinone methide intermediate that reacts with active-site nucleophiles. However, the main inhibition pathway of the 4-difluoromethyl derivative involved an unexpected process in which initially formed quinone methide diffuses from the active site and decomposes to an aldehyde in solution which then acts as a potent, almost irreversible STS inhibitor. This is the first example where this class of inactivator functions by in situ generation of an aldehyde. 6- and 8-mono- and difluoromethyl coumarin derivatives were also examined as quinone methide-generating suicide inhibitors of STS. The 6-monofluoromethyl derivative acted as a classic suicide inhibitor. The partition ratio of this compound was found to be very large indicating that this class of compounds is not likely suitable as an activity-based probe for proteomic profiling of sulfatases. Boronic acids derived from steroid and coumarin platforms were also examined as STS inhibitors with the goal of improving our understanding of substrate binding specificity of STS. Inhibition constants in the high nanomolar to low micromolar range were observed for the steroidal derivatives. The coumarin derivatives were poor inhibitors. These results suggest that the boronic acid moiety must be attached to a platform very closely resembling a natural substrate in order for it to impart a beneficial effect on binding affinity compared to its phenolic analog. The mode of inhibition observed was reversible and kinetic properties corresponding to the mechanism for slow-binding inhibitors were not observed. PTP1B catalyzes the dephosphorylation of phosphotyrosine residues in the insulin receptor kinase and is a key enzyme in the down regulation of insulin signaling. Inhibitors of PTP1B are considered to have potential as therapeutics for treating type II diabetes mellitus. The difluoromethylenesulfonic (DFMS) acid group, one of the best monoanionic phosphotyrosine mimics reported in the literature, was examined as a phosphotyrosine (pTyr) mimic in a non-peptidyl platform for PTP1B inhibition. The DFMS-bearing inhibitor was found to be an approximately 1000-fold poorer inhibitor than its phosphorus analogue. It was also found that the fluorines in the DFMS inhibitor contributed little to inhibitory potency. In addition, [sulfonamido(difluoromethyl)]-phenylalanine (F2Smp) was examined as a neutral pTyr mimic in commonly used hexapeptide and tripeptide platforms. F2Smp was found to be a poor pTyr mimic. These inhibition studies also revealed that the tripeptide platform is not suitable for assessing pTyr mimics for PTP1B inhibition. Taken together, the kinetic data on the inhibition of STS and PTP1B provide valuable information relevant for future design of inhibitors of these two therapeutic targets.

京都大学 / 新制・論文博士 / 博士(人間健康科学) / 乙第13562号 / 論人健博第12号 / 新制||人健||8(附属図書館) / (主査)教授 高桑 徹也, 教授 藤井 康友, 教授 長尾 美紀 / 学位規則第4条第2項該当 / Doctor of Human Health Sciences / Kyoto University / DFAM

No description available.

No description available.