Griseofulvin stabilizes microtubule dynamics, activates p53 and inhibits the proliferation of MCF-7 cells synergistically with vinblastine (original) (raw)
Related papers
Proceedings of the National Academy of Sciences, 2005
The antifungal drug griseofulvin inhibits mitosis strongly in fungal cells and weakly in mammalian cells by affecting mitotic spindle microtubule (MT) function. Griseofulvin also blocks cell-cycle progression at G 2 /M and induces apoptosis in human tumor cell lines. Despite extensive study, the mechanism by which the drug inhibits mitosis in human cells remains unclear. Here, we analyzed the ability of griseofulvin to inhibit cell proliferation and mitosis and to affect MT polymerization and organization in HeLa cells together with its ability to affect MT polymerization and dynamic instability in vitro . Griseofulvin inhibited cell-cycle progression at prometaphase/anaphase of mitosis in parallel with its ability to inhibit cell proliferation. At its mitotic IC 50 of 20 μM, spindles in blocked cells displayed nearly normal quantities of MTs and MT organization similar to spindles blocked by more powerful MT-targeted drugs. Similar to previously published data, we found that very h...
Synthesis and Characterization of Griseofulvin Derivatives as Microtubule-Stabilizing Agents
ChemistrySelect, 2022
Microtubules have been an attractive target of cancer drug discovery due to their highly dynamic nature during mitosis. Griseofulvin, a natural antifungal compound, is known to interfere with microtubule dynamics. In the present study, we prepared and analyzed twenty-seven novel griseofulvin derivatives. Three of these compounds had GI50 values <10 μM (5.74 to 9.7 μM) in breast cancer cell line CAL-51. The most promising compound ((2S,6’R)-4’-(benzhydrylamino)-7-chloro-4,6-dimethoxy-6’-methyl-3H-spiro[benzofuran-2,1’-cyclohexan]-3’-ene-2’,3-dione), was characterized as a microtubule-stabilizing agent with a GI50 value of 5.74±1.43 μM compared to 10.79±3.06 μM GI50 for parental griseofulvin. It also inhibited the proliferation of other cancer cell lines, including KB-3-1 and HCT116, with GI50 values of 1.19±0.34 μM and 2.48±0.40 μM, respectively. Treatment of cancer cells with it resulted in aberrant mitosis causing G2/M arrest. Finally, we show that this compound increased the expression of p53 protein and induced apoptotic cell death.
Mechanism of Action of Antitumor Drugs that Interact with Microtubules and Tubulin
Current Medicinal Chemistry-Anti-Cancer Agents, 2012
Microtubules, major structural components in cells, are the target of a large and diverse group of natural product anticancer drugs. Given the success of this class of drugs in cancer treatment, it can be argued that microtubules represent the single best cancer target identified to date. Microtubules are highly dynamic assemblies of the protein tubulin. They readily polymerize and depolymerize in cells, and they undergo two interesting kinds of dynamics called dynamic instability and treadmilling. These dynamic behaviors are crucial to mitosis, the process of chromosomal division to form new cells. Microtubule dynamics are highly regulated during the cell cycle by endogenous cellular regulators. In addition, many antitumor drugs and natural compounds alter the polymerization dynamics of microtubules, blocking mitosis, and consequently, inducing cell death by apoptosis. These drugs include several that inhibit microtubule polymerization at high drug concentrations, namely, the Vinca alkaloids, cryptophycins, halichondrins, estramustine, and colchicine. Another group of these compounds stimulates microtubule polymerization and stabilizes microtubules at high concentrations. These include Taxol™, Taxotere™, eleutherobins, epothilones, laulimalide, sarcodictyins, and discodermolide. Importantly, considerable evidence indicates that, at lower concentrations, these drugs have a common mechanism of action; they suppress the dynamics of microtubules without appreciably changing the mass of microtubules in the cell. The drugs bind to diverse sites on tubulin and at different positions within the microtubule, and they have diverse effects on microtubule dynamics. However, by their common mechanism of suppression microtubule dynamics, they all block mitosis at the metaphase/anaphase transition, and induce cell death. I. MICROTUBULES AS TARGETS FOR ANTI-CANCER DRUGS Microtubules are major dynamic structural components in cells. They are important in the development and maintenance of cell shape, in cell reproduction and division, in cell signaling, and in cellular movement [1]. Microtubules are the target of a diverse group of anticancer drugs, most of which are derived from natural products. Given the success of this class of drugs, the mitotic inhibitors, it can be argued that microtubules represent the single best cancer target identified to date [2] [3]. Microtubules are highly dynamic polymers of heterodimers of α and β tubulin, arranged parallel to a cylindrical axis to form tubes of 25 nm diameter that may be many µm long. Polymerization of microtubules occurs by a nucleation-elongation mechanism in which the formation of a short microtubule 'nucleus' is followed by elongation of the microtubule at its ends by the reversible, noncovalent addition of tubulin dimers. Microtubules are not simple equilibrium polymers. They exhibit complex polymerization dynamics that use energy provided by the hydrolysis of GTP, and these dynamics are crucial to their cellular functions. A large number of chemically diverse substances bind to
Microtubule assembly dynamics: An attractive target for anticancer drugs
IUBMB Life, 2008
Microtubules, composed of ab tubulin dimers, are dynamic polymers of eukaryotic cells. They play important roles in various cellular functions including mitosis. Microtubules exhibit differential dynamic behaviors during different phases of the cell cycle. Inhibition of the microtubule assembly dynamics causes cell cycle arrest leading to apoptosis; thus, qualifying them as important drug targets for treating several diseases including cancer, neuronal, fungal, and parasitic diseases. Although several microtubuletargeted drugs are successfully being used in cancer chemotherapy, the development of resistance against these drugs and their inherent toxicities warrant the development of new agents with improved efficacy. Several antimicrotubule agents are currently being evaluated for their possible uses in cancer chemotherapy. Benomyl, griseofulvin, and sulfonamides have been used as antifungal and antibacterial drugs. Recent reports have shown that these drugs have potent antitumor potential. These agents are shown to inhibit proliferation of different types of tumor cells and induce apoptosis by targeting microtubule assembly dynamics. However, unlike vincas and taxanes, which inhibit cancer cell proliferation in nanomolar concentration range, these agents act in micromolar range and are considered to have limited toxicities. Here, we suggest that these drugs may have a significant use in cancer chemotherapy when used in combination with other anticancer drugs.
Molecules
Tubulin isotypes are known to regulate microtubule stability and dynamics, as well as to play a role in the development of resistance to microtubule-targeted cancer drugs. Griseofulvin is known to disrupt cell microtubule dynamics and cause cell death in cancer cells through binding to tubulin protein at the taxol site. However, the detailed binding mode involved molecular interactions, and binding affinities with different human β-tubulin isotypes are not well understood. Here, the binding affinities of human β-tubulin isotypes with griseofulvin and its derivatives were investigated using molecular docking, molecular dynamics simulation, and binding energy calculations. Multiple sequence analysis shows that the amino acid sequences are different in the griseofulvin binding pocket of βI isotypes. However, no differences were observed at the griseofulvin binding pocket of other β-tubulin isotypes. Our molecular docking results show the favorable interaction and significant affinity o...
Biochemical Pharmacology, 2009
15-deoxi-Δ 12,14 -prostaglandin J 2 (15d-PGJ 2 ) is known to play an important role in the pathophysiology of carcinogenesis, however the molecular mechanisms underlying these effects are not yet fully understood. Recently, we have shown that 15d-PGJ 2 is a potent inducer of breast cancer cell death and that this effect is associated with a disruption of the microtubule cytoskeletal network. Here, we show that treatment of the MCF-7 breast cancer cell line with 15d-PGJ 2 induces an accumulation of cells in the G 2 /M compartment of the cell cycle and a marked disruption of the microtubule network. 15d-PGJ 2 treatment causes mitotic abnormalities that consist of failure to form a stable metaphase plate, incapacity to progress through anaphase, and failure to complete cytokinesis. 15d-PGJ 2 binds to tubulin through the formation of a covalent adduct with at least four cysteine residues in and -tubulin, as detected by hybrid triple-quadrupole mass spectrometry analysis. Overall, these results support the hypothesis that microtubule disruption and mitotic arrest, as a consequence of the binding of 15d-PGJ 2 to tubulin, can represent one important pathway leading to breast cancer cell death.
Molecular cancer therapeutics, 2003
Discodermolide is a new microtubule-targeted drug in Phase I clinical trials that inhibits tumor growth and induces G(2)-M cell cycle arrest. It is effective against paclitaxel-resistant cell lines and acts synergistically in combination with paclitaxel. Suppression of microtubule dynamics by microtubule-targeted drugs has been hypothesized to be responsible for their ability to inhibit mitotic progression and cell proliferation. To determine whether discodermolide blocks mitosis by an effect on microtubule dynamics, we analyzed the effects of discodermolide on microtubule dynamics in living A549 human lung cancer cells during interphase at concentrations that block mitosis and inhibit cell proliferation. We found that discodermolide (7-166 nM) significantly suppressed microtubule dynamic instability. At the IC(50) for proliferation (7 nM discodermolide, 72 h), overall dynamicity was reduced by 23%. The principal parameters of dynamic instability suppressed by discodermolide were th...
Cancer Research, 2004
Discodermolide is a new microtubule-targeted antimitotic drug in Phase I clinical trials that, like paclitaxel, stabilizes microtubule dynamics and enhances microtubule polymer mass in vitro and in cells. Despite their apparently similar binding sites on microtubules, discodermolide acts synergistically with paclitaxel to inhibit proliferation of A549 human lung cancer cells (L. Martello et al., Clin. Cancer Res., 6: 1978 -1987. To understand their synergy, we examined the effects of the two drugs singly and in combination in A549 cells and found that, surprisingly, their antiproliferative synergy is related to their ability to synergistically inhibit microtubule dynamic instability and mitosis. The combination of discodermolide and paclitaxel at their antiproliferative IC 50 s (7 nM for discodermolide and 2 nM for paclitaxel) altered all of the parameters of dynamic instability synergistically except the time-based rescue frequency. For example, together the drugs inhibited overall microtubule dynamicity by 71%, but each drug individually inhibited dynamicity by only 24%, giving a combination index (CI) of 0.23. Discodermolide and paclitaxel also synergistically blocked cell cycle progression at G 2 -M (41, 9.6, and 16% for both drugs together, for discodermolide alone, and for paclitaxel alone, respectively; CI ؍ 0.59), and they synergistically enhanced apoptosis (CI ؍ 0.85). Microtubules are unique receptors for drugs. The results suggest that ligands that bind to large numbers of binding sites on an individual microtubule can interact in a poorly understood manner to synergistically suppress microtubule dynamic instability and inhibit both mitosis and cell proliferation, with important consequences for combination clinical therapy with microtubule-targeted drugs.