Quantitative analysis of the effect of tubulin isotype expression on sensitivity of cancer cell lines to a set of novel colchicine derivatives (original) (raw)
Related papers
Interactions of long-chain homologues of colchicine with tubulin
European journal of medicinal chemistry, 2016
Several colchicine analogues in which the N-acetyl residue has been replaced by aliphatic, straight-chain acyl moieties, have been synthesized. These compounds show high cytotoxic activity at the nanomolar level against the tumoral cell lines HT-29, MCF-7 and A549. Some of them exhibit activities in the picomolar range against the HT-29 line and are thus two to three orders of magnitude more cytotoxic than colchicine. In this specific cell line, the activities were found to be closely related to the length of the acyl carbon chain, an increase in the latter giving rise to an increase in the cytotoxicity with a maximum in the range of 10-12 carbon atoms, followed by a decrease in activity with still longer chains. Some of the compounds inhibit microtubule assembly and induce the formation of abnormal polymers and present in most cases better apparent affinity constants than colchicine. In addition, at IC50 concentrations the analogues block the cell cycle of A549 cells in the G2/M ph...
Antimitotic activity of colchicine and the structural basis for its interaction with tubulin
Medicinal Research Reviews, 2008
In this review, an attempt has been made to throw light on the mechanism of action of colchicine and its different analogs as anti-cancer agents. Colchicine interacts with tubulin and perturbs the assembly dynamics of microtubules. Though its use has been limited because of its toxicity, colchicine can still be used as a lead compound for the generation of potent anti-cancer drugs. Colchicine binds to tubulin in a poorly reversible manner with high activation energy. The binding interaction is favored entropically. In contrast, binding of its simple analogs AC or DAAC is enthalpically favored and commences with comparatively low activation energy. Colchicine–tubulin interaction, which is normally pH dependent, has been found to be independent of pH in the presence of microtubule-associated proteins, salts or upon cleavage of carboxy termini of tubulin. Biphasic kinetics of colchicines–tubulin interaction has been explained in light of the variation in the residues around the drug-binding site on β-tubulin. Using the crystal structure of the tubulin–DAMAcolchicine complex, a detailed discussion on the pharmacophore concept that explains the variation of affinity for different colchicine site inhibitors (CSI) has been discussed. © 2007 Wiley Periodicals, Inc. Med Res Rev, 28, No. 1, 155–183, 2008
Cells, 2018
Specific modifications of colchicine followed by synthesis of its analogues have been tested in vitro with the objective of lowering colchicine toxicity. Our previous studies have clearly shown the anticancer potential of double-modified colchicine derivatives in C-7 and C-10 positions. Here, a series of novel triple-modified colchicine derivatives is reported. They have been obtained following a four-step strategy. In vitro cytotoxicity of these compounds has been evaluated against four human tumor cell lines (A549, MCF-7, LoVo, and LoVo/DX). Additionally, the mode of binding of the synthesized compounds was evaluated in silico using molecular docking to a 3D structure of β-tubulin based on crystallographic data from the Protein Data Bank and homology methodology. Binding free energy estimates, binding poses, and MlogP values of the compounds were obtained. All triple-modified colchicine derivatives were shown to be active at nanomolar concentrations against three of the investigated cancer cell lines (A549, MCF-7, LoVo). Four of them also showed higher potency against tumor cells over normal cells as confirmed by their high selectivity index values. A vast majority of the synthesized derivatives exhibited several times higher cytotoxicity than colchicine, doxorubicin, and cisplatin.
Characterization of the Colchicine Binding Site on Avian Tubulin Isotype βVI
Biochemistry, 2010
Tubulin, the basic component of microtubules, is present in most eukaryotic cells as multiple gene products, called isotypes. The major tubulin isotypes are highly conserved in terms of structure and drug binding capabilities. The tubulin isotype βVI, however, is significantly divergent from the other isotypes in sequence, assembly properties and function. It is the major β-tubulin isotype of hematopoietic tissue and forms the microtubules of platelet marginal bands. The interaction of the major tubulin isotypes βI, βII, βIII and βIV with antimicrotubule drugs has been widely studied, but little is known about the drug binding properties of tubulin isotype βVI. In this investigation, we characterized the activity of various colchicine-site ligands with tubulin isolated from Gallus gallus erythrocytes (CeTb), which is ~95% βVI. Colchicine binding is thought to be a universal property of higher eukaryotic tubulin; however, we were unable to detect colchicine binding to CeTb under any experimental conditions. Podophyllotoxin and nocodazole, other colchicine-site ligands with divergent structures, were able to inhibit paclitaxel-induced CeTb assembly. Surprisingly, the colchicine isomer allocolchicine also inhibited CeTb assembly and displayed measurable, moderate affinity for CeTb (Ka = 0.18 × 10 5 M −1 vs. 5.0 × 10 5 M −1 for bovine brain tubulin). Since allocolchicine and colchicine differ in their C ring structures, the two C-ring colchicine analogues were also tested for CeTb binding. Kinetic experiments indicate that thiocolchicine and chlorocolchicine bind to CeTb, but very slowly and with low affinity. Molecular modeling of CeTb identified five divergent amino acid residues within 6 Å of the colchicine binding site compared to βI, βII, and βIV; three of these amino acids are also altered in βIII-tubulin. Interestingly, the altered amino acids are in the vicinity of the A ring region of the colchicine binding site rather than the C ring region. We propose that the amino acid differences in the binding site constrict the A ring binding domain in CeTb, which interferes with the positioning of the trimethoxyphenyl A ring and prevents C ring binding site interactions from efficiently occurring. Allocolchicine is able to accommodate the altered binding mode because of its smaller ring size and more flexible C ring substituents. The sequence of the colchicine binding domain of CeTb βVI-isotype is almost identical to that of it human hematopoietic counterpart. Thus, through analysis of the interactions of ligands with CeTb, it may be possible to discover colchicine site ligands that specifically target tubulin in human hematopoietic cells. ., sbane@binghamton.edu. SUPPORTING INFORMATION AVAILABLE The inhibition of paclitaxel induced CeTb assembly by allocolchicine, an illustration of three dimensional alignment of tubulin-bound colchicine and podophyllotoxin, and sequence alignment of chicken erythrocyte βVI and human β1 tubulin. This material is available free of charge via the internet at
Molecular Cancer Therapeutics, 2008
Tubulin is a validated target for antitumor drugs. However, the effectiveness of these microtubule-interacting agents is limited by the fact that they are substrates for drug efflux pumps (P-glycoprotein) and/or by the acquisition of point mutations in tubulin residues important for drug-tubulin binding. To bypass these resistance systems, we have identified and characterized a novel synthetic imidazole derivative IRC-083927, which inhibits the tubulin polymerization by a binding to the colchicine site. IRC-083927 inhibits in vitro cell growth of human cancer cell lines in the low nanomolar range. More interesting, it remains highly active against cell lines resistant to microtubule-interacting agents (taxanes, Vinca alkaloids, or epothilones). Such resistances are due to the presence of efflux pumps (NCI-H69/LX4 resistant to navelbine and paclitaxel) and/or the presence of mutations on β-tubulin and on α-tubulin and β-tubulin (A549.EpoB40/A549.EpoB480 resistant to epothilone B or p...