ABSTRACT
A series of new 3,5-diaryl isoxazoline/isoxazole linked 2,3-dihydro quinazolinone hybrids with different linker architectures have been designed and synthesized. These compounds have been evaluated for their anticancer activity. One of the compounds 4c amongst this series has shown promising anticancer activity. Further some detailed biological assays relating to the cell cycle aspects and tubulin depolymerization activity have been examined with a view to understand the mechanism of action of this conjugate.
Subject(s)
Antineoplastic Agents/pharmacology , Isoxazoles/pharmacology , Quinazolinones/pharmacology , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/chemistry , Cell Cycle/drug effects , Cell Line, Tumor , Cell Proliferation/drug effects , Dose-Response Relationship, Drug , Drug Screening Assays, Antitumor , Humans , Isoxazoles/chemical synthesis , Isoxazoles/chemistry , Molecular Structure , Quinazolinones/chemical synthesis , Quinazolinones/chemistry , StereoisomerismABSTRACT
A series of new cinnamido-pyrrolo[2,1-c][1,4]benzodiazepine conjugates (4a-d and 5a-d) and their dimers (6a-d) have been designed, synthesized and evaluated for their biological activity. The anticancer screening of compound 4a by the NCI exhibited significant GI50 values ranging from 68 to 732 nM against 53 of 59 human cancer cell lines tested. Compounds 5a-d and 6a-d have also shown remarkable cytotoxic activity with GI50 values <0.1 microM concentrations in a large number of cell lines. Interestingly, compounds 5b and 6b have been identified as a new class of inhibitors of tubulin polymerization and their action has been rationalized by the cell cycle arrest in G0 and G2/M phase.
Subject(s)
Antimitotic Agents/chemical synthesis , Antimitotic Agents/pharmacology , Benzodiazepines/chemical synthesis , Benzodiazepines/pharmacology , Antimitotic Agents/chemistry , Apoptosis/drug effects , Benzodiazepines/chemistry , Cell Cycle/drug effects , Cell Line, Tumor , Cell Nucleus/drug effects , Cell Nucleus/metabolism , Humans , Inhibitory Concentration 50 , Protein Multimerization/drug effects , Protein Structure, Quaternary , Tubulin/chemistry , Tubulin/metabolismABSTRACT
C2-Fluoro substituted DC-81, and its dimers that comprise of two C2-fluoro substituted DC-81 subunits tethered to their C8-position through simple alkane spacers as well as piperazine moiety side-armed with symmetrical alkyloxy spacers have been designed and synthesized. These fluoro substituted pyrrolo[2,1-c][1,4]benzodiazepines have shown remarkable DNA-binding ability and most of them possess promising anticancer activity, having GI(50) values in micromolar to nanomolar concentration range. DNA thermal denaturation studies show that some of these compounds (14a-c and 15) increase the DeltaT(m) values in the range of 28.9-38 degrees C, and this is further confirmed by the restriction endonuclease studies. This study illustrates the importance of introducing fluoro substitution at the C2-position apart from the incorporation of a piperazine ring in between the alkyloxy linker for enhancement of the DNA-binding ability in comparison to DSB-120 and SJG-136 (DeltaT(m)=10.2 and 25.7 degrees C). Moreover, the variations in the DNA-binding ability with respect to fluoro substitution in this class of dimers has been investigated by molecular modeling studies. Some representative C2-fluoro substituted dimers (8a and 14a) have also exhibited significant anticancer activity in the 60 cancer cell line assay of the National Cancer Institute (NCI).
