Conjugates of Modified Cryptophycins and RGD-Peptides Enter Target Cells by Endocytosis
摘要:
Tumor targeting anticancer drug conjugates that contain a tumor recognition motif (homing device) are of high current relevance. Cryptophycins, naturally occurring cytotoxic cyclo-depsipeptides, have been modified by total synthesis to provide analogues suitable for conjugation to peptide-based homing devices. An array of functionalized beta(2)-amino acids was synthesized and incorporated into cryptophycins. All analogues proved to be highly active in the cytotoxicity assay using the human cervix carcinoma cell line KB-3-1 and its multidrug-resistant subclone KB-V1. Conformational analysis of cryptophycin-52 and two synthetic analogues was performed by NMR and MD methods to obtain information on the influence of the unit C configuration on the overall conformation. An azide-functionalized cryptophycin was connected by CuAAC to an alkyne-containing fluorescently labeled cyclic RGD-peptide as the homing device for internalization studies. Confocal fluorescence microscopy proved integrin-mediated internalization by endocytosis and final lysosomal localization of the cryptophycin prodrug.
Antineoplastic Agents. 561. Total Synthesis of Respirantin<sup>1a</sup>
作者:George R. Pettit、Thomas H. Smith、Song Feng、John C. Knight、Rui Tan、Robin K. Pettit、Peter A. Hinrichs
DOI:10.1021/np0680735
日期:2007.7.1
Totalsynthesis of the 18-membered ring cyclodepsipeptide believed to be respirantin (1b) has been achieved. The key step in the synthesis is an intramolecular transesterification of the beta-ketoester alcohol 6 to afford the protected macrocycle 5. The synthetic product was shown to be identical to a natural product presumed to be respirantin (1b), and the absolute stereochemistry of six of the seven
Rapid Entry into the Cryptophycin Core via an Acyl-β-lactam Macrolactonization: Total Synthesis of Cryptophycin-24
作者:MariJean Eggen、Sajiv K. Nair、Gunda I. Georg
DOI:10.1021/ol010044s
日期:2001.6.1
[see structure]. An efficient, conciseapproach to the macrolide core of the cryptophycins, potent antimitotic agents, has been achieved. The reaction sequence features a novel macrolactonization utilizing a reactive acyl-beta-lactam intermediate that incorporates the beta-amino acid moiety within the 16-membered macrolide core. This highly modular approach, which allows for multiple alterations throughout
An endocyclic trans-amide linkage within the macrocyclic antitumor agent cryptophycin-52 was replaced by a 1,4-disubstituted 1H-1,2,3-triazole ring. Macrocyclisation of the triazole analogue was accomplished by macrolactamization as well as by Cu(I)-mediated "click"-cyclization. Compared to cryptophycin-52, in vitro cytotoxicity of "clicktophycin-52" against the multidrug resistant human cancer cell line KB-V1 is only slightly reduced.