Octa-Substituted Anionic Porphyrins: Topoisomerase I Inhibition and Tumor Cell Apoptosis Induction

Nitrile-containing copper(ii) porphyrin coordination complexes for efficient anticancer activity and mechanism research

Synthesis and anticancer activity of nitrile-containing copper(ii) porphyrin coordination complexes.

Comparative in vitro Studies of the Topoisomerase I Inhibition and Anticancer Activities of Metallated N-Confused Porphyrins and Metallated Porphyrins

Using the original approach, a series of metallated N-confused porphyrins and metallated porphyrins have been synthesized and characterized. For all the synthesized porphyrins, in vitro studies of cytotoxic activity against K562, U937, HL-60, Jurkat, A549 and HeLa cancer cell lines, the ability to induce apoptosis and effects on the cell cycle as well as the kinetics of proliferative activity of porphyrins and their respective metallated complexes in real time have been developed. The inhibitory activity of metallated porphyrins against human topoisomerase I and the possible mechanism of inhibition have been carried out by modelling using molecular docking.

Neutral Porphyrin Derivative Exerts Anticancer Activity by Targeting Cellular Topoisomerase I (Top1) and Promotes Apoptotic Cell Death without Stabilizing Top1-DNA Cleavage Complexes

Camptothecin (CPT) selectively traps topoisomerase 1-DNA cleavable complexes (Top1cc) to promote anticancer activity. Here, we report the design and synthesis of a new class of neutral porphyrin derivative 5,10-bis(4-carboxyphenyl)-15, 20-bis(4-dimethylaminophenyl)porphyrin (compound 8) as a potent catalytic inhibitor of human Top1. In contrast to CPT, compound 8 reversibly binds with the free enzyme and inhibits the formation of Top1cc and promotes reversal of the preformed Top1cc with CPT. Compound 8 induced inhibition of Top1cc formation in live cells was substantiated by fluorescence recovery after photobleaching (FRAP) assays. We established that MCF7 cells treated with compound 8 trigger proteasome-mediated Top1 degradation, accumulate higher levels of reactive oxygen species (ROS), PARP1 cleavage, oxidative DNA fragmentation, and stimulate apoptotic cell death without stabilizing apoptotic Top1-DNA cleavage complexes. Finally, compound 8 shows anticancer activity by targeting cellular Top1 and preventing the enzyme from directly participating in the apoptotic process.

Diversity, isomer composition, and design of combinatorial libraries of tetrapyrrole macrocycles

Combinatorial libraries of substituted tetrapyrrole macrocycles, which can now be prepared via a variety of approaches, typically are rich in isomers. Terminology for describing such isomers (due to distinct patterns of peripheral substituents) is delineated in several illustrative examples. A hierarchical relationship exists of molecular formula, condensed formula(s) of substituents, set(s) of pyrrole collocates (conveying each pair of β-pyrrolic substituents), and isomers of substituted tetrapyrrole macrocycles. Isomers with identical pyrrole collocate sets can arise owing to distinct positions or orientations of the (homo- or hetero-substituted) pyrrolic units in a macrocycle. Consideration of a handful of virtual combinatorial libraries illustrates tradeoffs of library size, chemical richness, and isomeric content. As one example, octa-derivatization of a tetrapyrrole scaffold with eight reactants A–H affords 2,099,728 members (99.7% isomers, 82,251 pyrrole collocate sets, and 6,435 condensed formulas) whereas the reversible self-condensation of four pyrroles that bear the same eight entities (AB, CD, EF, GH) affords 538 members (93.5% isomers, 35 pyrrole collocate sets, and 35 condensed formulas). Derivatization affords all combinations and permutations whereas self-condensation of substituted pyrroles carries collocational restrictions. Understanding such tradeoffs and the structural origin of isomerism are important aspects in the design of tetrapyrrole combinatorial libraries.

Construction and transmembrane dissociation behavior of supramolecular assembly of quinolinocyclodextrin with porphyrin

Through the stoichiometric 2 : 1 coordination of Zn(2+) with 4-amino-N-(2-methylquinolin-8-yl)benzenesulfonamide-modified per-methyl-beta-cyclodextrin (MQAS-PMCD) and the strong inclusion complexation of permethyl-beta-cyclodextrin cavity with meso-tetrakis-(4-sulfonatophenyl)-porphyrin (TSPP), an environment-sensitive Zn(2+)/cyclodextrin/porphyrin triad supramolecular assembly was constructed, and its structure was fully characterized by UV/vis spectroscopy, fluorescence spectroscopy, powder X-ray diffraction (XRD), scanning tunneling microscopy (STM) and transmission electron microscopy (TEM). Fluorescence spectrometric studies showed that this supramolecular assembly was stable and barely emitted green fluorescence in water due to the energy transfer process, but gave the strong green fluorescence when changing to a hydrophobic environment due to the disruption of the assembly. Further studies on the cell staining experiments by means of fluorescence microscopy showed that this supramolecular assembly was disrupted to release the MQAS-PMCD/Zn(2+) and porphyrin components when interacting with the cell membrane. Subsequently, the released MQAS-PMCD/Zn(2+) complex remained in the cell membrane, while the porphyrin component entered the cells. This transmembrane dissociation property of the supramolecular assembly will enable its application in the delivery of biological and drug molecules containing the anionic porphyrin skeleton such as beta-octaphenyl-meso-tetra(4-carboxyl)-phenylporphyrin and so on.