Aminopurvalanol A

M-phase regulation of the recruitment of mRNAs onto polysomes using the CDK1/cyclin B inhibitor aminopurvalanol.[Pubmed:12821124]

Biochem Biophys Res Commun. 2003 Jul 11;306(4):880-6.

Translation under the control of the universal cell cycle regulator CDK1/cyclin B was investigated during the first cell cycle in sea urchin embryos. The CDK1/cyclin B inhibitor Aminopurvalanol Arrested embryos at the G2/M transition. Polysomal mRNAs were purified from control and arrested embryos, and screened for specific mRNA recruitment or release at M-phase by subtractive hybridization. The polysomal repartition of clones issued from this screen was analyzed. Three specific mRNAs were selectively recruited onto polysomes at M-phase. Conversely, two other specific mRNAs were released from polysomes. The isolation of these translationally regulated mRNAs gives now important tools for insights into the regulation of protein synthesis by the cell cycle regulator CDK1-cyclin B.

Intracellular targets of cyclin-dependent kinase inhibitors: identification by affinity chromatography using immobilised inhibitors.[Pubmed:10873834]

Chem Biol. 2000 Jun;7(6):411-22.

BACKGROUND: Chemical inhibitors of cyclin-dependent kinases (CDKs) have great therapeutic potential against various proliferative and neurodegenerative disorders. Olomoucine, a 2,6,9-trisubstituted purine, has been optimized for activity against CDK1/cyclin B by combinatorial and medicinal chemistry efforts to yield the purvalanol inhibitors. Although many studies support the action of purvalanols against CDKs, the actual intracellular targets of 2,6, 9-trisubstituted purines remain unverified. RESULTS: To address this issue, purvalanol B (95. ) and an N6-methylated, CDK-inactive derivative (95M. ) were immobilized on an agarose matrix. Extracts from a diverse collection of cell types and organisms were screened for proteins binding purvalanol B. In addition to validating CDKs as intracellular targets, a variety of unexpected protein kinases were recovered from the 95. matrix. Casein kinase 1 (CK1) was identified as a principal 95. matrix binding protein in Plasmodium falciparum, Leishmania mexicana, Toxoplasma gondii and Trypanosoma cruzi. Purvalanol compounds also inhibit the proliferation of these parasites, suggesting that CK1 is a valuable target for further screening with 2,6,9-trisubstituted purine libraries. CONCLUSIONS: That a simple batchwise affinity chromatography approach using two purine derivatives facilitated isolation of a small set of highly purified kinases suggests that this could be a general method for identifying intracellular targets relevant to a particular class of ligands. This method allows a close correlation to be established between the pattern of proteins bound to a small family of related compounds and the pattern of cellular responses to these compounds.

Synthesis and application of functionally diverse 2,6,9-trisubstituted purine libraries as CDK inhibitors.[Pubmed:10375538]

Chem Biol. 1999 Jun;6(6):361-75.

BACKGROUND: Purines constitute a structural class of protein ligands involved in mediating an astonishing array of metabolic processes and signal pathways in all living organisms. Synthesis of purine derivatives targeting specific purine-binding proteins in vivo could lead to versatile lead compounds for use as biological probes or drug candidates. RESULTS: We synthesized several libraries of 2,6, 9-trisubstituted purines using both solution- and solid-phase chemistry, and screened the compounds for inhibition of cyclin-dependent kinase (CDK) activity and human leukemic cell growth. Lead compounds were optimized by iterative synthesis based on structure-activity relationships (SARs), as well as analysis of several CDK-inhibitor cocrystal structures, to afford several interesting compounds including one of the most potent CDK inhibitors known to date. Unexpectedly, some compounds with similar CDK inhibitory activity arrested cellular proliferation at distinctly different phases of the cell cycle and another inhibitor directly induced apoptosis, bypassing cell-cycle arrest. Some of these compounds selectively inhibited growth of cells derived from specific tumors. CONCLUSIONS: 2,6,9-Trisubstituted purines have various and potent biological activities, despite high concentrations of competing endogenous purine ligands in living cells. Purine libraries constitute a versatile source of small molecules that affect distinct biochemical pathways mediating different cellular functions.