This thesis describes the synthesis and biochemical evaluation of a variety of cyclophellitol based activity-based probes and inhibitors targeting various endo- and exo-acting retaining... Show moreThis thesis describes the synthesis and biochemical evaluation of a variety of cyclophellitol based activity-based probes and inhibitors targeting various endo- and exo-acting retaining glycosidases. In the last two decades a variety of probes and inhibitors for (hemi)cellulose degrading enzymes have been developed. However, at the onset of the work described in this thesis the focus has been mainly on cellulases, xylanases, xyloglucanases and glycanases. Chapter 2 describes the design and synthesis of a first generation of inhibitors and probes for β-mannanases. The general scaffold is composed of a β-1,4-linked mannobioside featuring either an epoxide or an aziridine warhead. All synthesized probes feature a linker attached to the nonreducing end and are condensed with either biotin or Cy5. Biochemical evaluation in an Aspergillus niger secretome revealed the utility of these compounds but also the limitations. The probes react efficiently with some endo-β-mannanases yet lack reactivity with others. Chapter 3 describes the design and synthesis of a second generation of β-mannanase probes and inhibitors designed to overcome the limitations of the first generation by changing the general scaffold. In this chapter two conceptually distinct ABP scaffolds are presented: a β-1,4-linked mannotriose and a β-1,4-linked manno-gluco configured scaffold. The second generation Cy5 probes are evaluated in Aspergillus niger secretomes and compared to the first generation. Chapter 4 describes studies towards the design and synthesis of inhibitors and ABPS for both α-N-acetylglucosaminidase and α-Nacetylgalactosaminidase. The chapter introduces an orthogonally protected ribose building block as common intermediate from which both mannoseand talose configured cyclohexenes are synthesized. Furthermore it describes a late state stereoselective C-2 inversion with an azide to install a 20 nitrogen atom at C-2. Chapter 5 presents a summary and suggestions forfuture research. Show less
Boer, C. de; Armstrong, Z.W.B; Lit, V.A.J.; Barash, U.; Ruijgrok, G.; Boyango, I.; ... ; Wu, L. 2022
Heparan sulfate proteoglycans (HSPGs) mediate essential interactions throughout the extracellular matrix (ECM), providing signals that regulate cellular growth and development. Altered HSPG... Show moreHeparan sulfate proteoglycans (HSPGs) mediate essential interactions throughout the extracellular matrix (ECM), providing signals that regulate cellular growth and development. Altered HSPG composition during tumorigenesis strongly aids cancer progression. Heparanase (HPSE) is the principal enzyme responsible for extracellular heparan sulfate catabolism and is markedly up-regulated in aggressive cancers. HPSE overactivity degrades HSPGs within the ECM, facilitating metastatic dissemination and releasing mitogens that drive cellular proliferation. Reducing extracellular HPSE activity reduces cancer growth, but few effective inhibitors are known, and none are clinically approved. Inspired by the natural glycosidase inhibitor cyclophellitol, we developed nanomolar mechanism-based, irreversible HPSE inhibitors that are effective within physiological environments. Application of cyclophellitol-derived HPSE inhibitors reduces cancer aggression in cellulo and significantly ameliorates murine metastasis. Mechanism-based irreversible HPSE inhibition is an unexplored anticancer strategy. We demonstrate the feasibility of such compounds to control pathological HPSE-driven malignancies. Show less
