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Anticancer Activity Of A Thymidine Quinoxaline Conjugate Is Modulated By Cytosolic Thymidine Pathways, Qiong Wei, Haijuan Liu, Honghao Zhou, Dejun Zhang, Zhiwei Zhang, Qibing Zhou

Medicinal Chemistry Publications

Background

High levels of thymidine kinase 1 (TK1) and thymidine phosphorylase (TYMP) are key molecular targets by thymidine therapeutics in cancer treatment. The dual roles of TYMP as a tumor growth factor and a key activation enzyme of anticancer metabolites resulted in a mixed outcome in cancer patients. In this study, we investigated the roles of TK1 and TYMP on a thymidine quinoxaline conjugate to evaluate an alternative to circumvent the contradictive role of TYMP.

Methods

TK1 and TYMP levels in multiple liver cell lines were assessed along with the cytotoxicity of the thymidine conjugate. Cellular accumulation of the thymidine …

6-Hydroxyflavone And Derivatives Exhibit Potent Anti-Inflammatory Activity Among Mono-, Di- And Polyhydroxylated Flavones In Kidney Mesangial Cells, Xing Wang, Zhiwei Wang, Preetpal Singh Sidhu, Umesh R. Desai, Qibing Zhou

Medicinal Chemistry Publications

Inflammatory responses by kidney mesangial cells play a critical role in the glomerulonephritis. The anti-inflammatory potential of nineteen mono-, di- and polyhydroxylated flavones including fisetin, quercetin, morin, tricetin, gossypetin, apigenin and myricetin were investigated on rat mesangial cells with lipopolysaccharide (LPS) as the inflammatory stimuli. 6-Hydroxyflavone and 4′,6-dihydroxyflavone exhibited high activity with IC50 in the range of 2.0 μM, a much better inhibition potential in comparison to the well-studied polyhydroxylated flavones. Interestingly, the anti-inflammatory activity was not due to direct quenching of NO radicals. Investigation on derivatives with methylation, acetylation or sulfation of 6-hydroxyl group revealed that 6-methoxyflavone was the …

Plasmin Regulation Through Allosteric, Sulfated, Small Molecules, Rami A. Al-Horani, Rajesh Karuturi, Domonique T. White, Umesh R. Desai

Medicinal Chemistry Publications

Plasmin, a key serine protease, plays a major role in clot lysis and extracellular matrix remodeling. Heparin, a natural polydisperse sulfated glycosaminoglycan, is known to allosterically modulate plasmin activity. No small allosteric inhibitor of plasmin has been discovered to date. We screened an in-house library of 55 sulfated, small glycosaminoglycan mimetics based on nine distinct scaffolds and varying number and positions of sulfate groups to discover several promising hits. Of these, a pentasulfated flavonoid-quinazolinone dimer 32 was found to be the most potent sulfated small inhibitor of plasmin (IC50 = 45 μM, efficacy = 100%). Michaelis-Menten kinetic studies revealed …

Structural Studies Of Aav2 Rep68 Reveal A Partially Structured Linker And Compact Domain Conformation, Faik N. Musayev, Francisco Zarate-Perez, Martino Bardelli, Clayton Bishop, Emil F. Saniev, R. Michael Linden, Els Henckaerts, Carlos R. Escalante

Medicinal Chemistry Publications

Adeno-associated virus (AAV) nonstructural proteins Rep78 and Rep68 carry out all DNA transactions that regulate the AAV life cycle. They share two multifunctional domains: an N-terminal origin binding/nicking domain (OBD) from the HUH superfamily and a SF3 helicase domain. A short linker of ~20 amino acids that is critical for oligomerization and function connects the two domains. Although X-ray structures of the AAV5 OBD and AAV2 helicase domains have been determined, information about the full-length protein and linker conformation is not known. This article presents the solution structure of AAV2 Rep68 using small-angle X-ray scattering (SAXS). We first determined the …

A Simple Method For Discovering Druggable, Specific Glycosaminoglycan-Protein Systems. Elucidation Of Key Principles From Heparin/Heparan Sulfate-Binding Proteins, Aurijit Sarkar, Umesh R. Desai

Medicinal Chemistry Publications

Glycosaminoglycans (GAGs) affect human physiology and pathology by modulating more than 500 proteins. GAG-protein interactions are generally assumed to be ionic and nonspecific, but specific interactions do exist. Here, we present a simple method to identify the GAG-binding site (GBS) on proteins that in turn helps predict high specific GAG–protein systems. Contrary to contemporary thinking, we found that the electrostatic potential at basic arginine and lysine residues neither identifies the GBS consistently, nor its specificity. GBSs are better identified by considering the potential at neutral hydrogen bond donors such as asparagine or glutamine sidechains. Our studies also reveal that an …