Recurrent glioblastoma multiforme (GBM), insensitive against most therapeutic interventions, has low

Recurrent glioblastoma multiforme (GBM), insensitive against most therapeutic interventions, has low response and survival rates. cancers. Despite all treatments including neurosurgical resection followed by postoperative radiotherapy, the overall survival instances of individuals are unsatisfactory (Walker CC-401 cost et al 1978). Consequently our aim is to use the potential for temozolomide (TMZ) to treat GBM by improving drugs potency. The combination of the oral administration of TMZ with radiotherapy led CC-401 cost to longer survival instances (Combs et al 2005) by delaying tumor progression. Including simple oral application increased the interest in using TMZ to treat GBM (Osoba et al 2000). The action of TMZ (8-carbamoyl-3-methylimidazo [5,1-d]-1,2,3,5-tetrazin-4(3H)-one) has been extensively studied, primarily in leukemia and lymphoma cells. TMZ is rapidly resorbed after oral software and spontaneously decomposes in aqueous remedy at physiological pH to the cytotoxic methylating agent 5-(3-methyltriazen-1-y1)imidazole-4-carboxamide (MTIC) (Tsang et al 1990). The cytotoxicity of TMZ appears to be mediated primarily through adduction of methyl organizations to O6 positions of guanine (O6mG) CC-401 cost in genomic DNA (Denny et al 1994) followed by recognition of this adduct from the mismatch restoration system (MMR), which mispairs with thymine during the next cycle of DNA replication. The half-life of TMZ (Riccardi et al 2003) in plasma and non-target-gene-specific alkylating mode of action can result in undesired adverse reactions which then hamper the restorative outcome efficiency. For this reason fresh TMZ-derivatives were designed. The use of the peptide-based nuclear localization sequence (NLS) (Braun et al 2002; Heckl et al 2002), which leads to an active nuclear focusing on, could minimize existing handicaps. Because of their higher molecular mass and their physico-chemical characteristics the transport across the cellular membrane of TMZ-NLS peptide conjugates is still poor. Consequently a carrier molecule is needed, which can C after the transmembrane passage into the cytoplasm C discharge its TMZ-NLS-Cys cargo so that a sufficient concentration of pharmacologically active molecules can reach their target site in the nucleus. With this context several viral (Tabin et al 1982; Seymour 1992; Advani et al 2002; Conlon and Flotte 2004; Palmer and Ng 2005) and non-viral (Bangham and Papahadjopoulos 1966; Derossi et al 1996; Storm and Crommelin 1997; Vives et al 1997; Bourne et al 2000; Merdan et al 2002) well-documented transport vehicles were designed by different laboratories. They are able to facilitate the Rabbit Polyclonal to MRC1 cellular transport of molecules with improper physico-chemical properties for the transmembrane passage. Our considerations for improving the transport of TMZ into the cell nucleus led to a search for suitable ligation modes of TMZ having a nuclear address peptide (a) which in turn is connected to carrier molecules (b) (Table 1). Table 1 Schematic pattern of the TMZ-NLS and transport-peptides modules (modular schemata of the TMZ-BioShuttle) Open in a separate window The table depicts the transmembrane transport module (lower part of the table) and the nuclear localization sequence (NLS) connected with the revised dienophile component tetracyclo-[5.4.21,7.O2,6.O8,11]3,5-dioxo-4-aza-9,12-trideca-diene (TCT) via the ?-amino coupling of the lysine (top part of the table). A brief comment is required here for a better understanding of the following paragraphs. In chemistry the meaning of ligation reaction is the basis of Diels-Alder chemistry, on which we focus here, in contrast that in molecular biology, in which it means the ligase-catalized connection of nucleic acids in the 3-hydoxy group and the 5-phosphate terminus. This 1st ligation (a) should permit a multi-modular connection of practical peptides and formation of higher peptide chain lengths compared to the different developing techniques. It should also achieve a higher functional variability concerning the coupled peptides or substances in relation to mono-modular peptides generated by simple solid phase peptide synthesis or by recombinant chemistry. However the fast and selective covalent linkage of biologically active molecules under physiological conditions still represents a great challenge in the chemical praxis. For this reason, such a ligation reaction should meet the following criteria: (1) quick course of the reaction, (2) self-employed of solvent properties, (3) no part reaction with other practical groups present in the molecule, (4) no unique coupling-reagents, (5) an economical procedure,.