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Journal of Medicinal Chemistry Oct 2020A new class of pyrrolo[2',3':3,4]cyclohepta[1,2-][1,2]oxazoles was synthesized for the treatment of hyperproliferative pathologies, including neoplasms. The new...
A new class of pyrrolo[2',3':3,4]cyclohepta[1,2-][1,2]oxazoles was synthesized for the treatment of hyperproliferative pathologies, including neoplasms. The new compounds were screened in the 60 human cancer cell lines of the NCI drug screen and showed potent activity with GI values reaching the nanomolar level, with mean graph midpoints of 0.08-0.41 μM. All compounds were further tested on six lymphoma cell lines, and eight showed potent growth inhibitory effects with IC values lower than 500 nM. Mechanism of action studies showed the ability of the new [1,2]oxazoles to arrest cells in the G2/M phase in a concentration dependent manner and to induce apoptosis through the mitochondrial pathway. The most active compounds inhibited tubulin polymerization, with IC values of 1.9-8.2 μM, and appeared to bind to the colchicine site. The G2/M arrest was accompanied by apoptosis, mitochondrial depolarization, generation of reactive oxygen species, and PARP cleavage.
Topics: Antimitotic Agents; Antineoplastic Agents; Apoptosis; Cell Proliferation; Cells, Cultured; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; G2 Phase Cell Cycle Checkpoints; HeLa Cells; Humans; Mitosis; Models, Molecular; Molecular Structure; Oxazoles; Structure-Activity Relationship
PubMed: 32986419
DOI: 10.1021/acs.jmedchem.0c01315 -
Bioorganic & Medicinal Chemistry Oct 2018The role and the importance of the sulfonate moiety in phenyl 4-(2-oxo-3-alkylimidazolidin-1-yl)benzenesulfonates (PAIB-SOs) were assessed using its bioisosteric...
The role and the importance of the sulfonate moiety in phenyl 4-(2-oxo-3-alkylimidazolidin-1-yl)benzenesulfonates (PAIB-SOs) were assessed using its bioisosteric sulfonamide equivalent leading to new cytochrome P450 1A1 (CYP1A1)-activated prodrugs designated as 4-(3-alkyl-2-oxoimidazolidin-1-yl)-N-phenylbenzenesulfonamides (PAIB-SAs). PAIB-SAs are active in the submicromolar to low micromolar range showing selectivity toward CYP1A1-expressing MCF7 cells as compared to cells devoid of CYP1A1 activity such as MDA-MB-231 and HaCaT cells. The most potent, PAIB-SA 13, bearing a trimethoxyphenyl group on ring B blocks the cell cycle progression in G2/M phase, disrupts the microtubule dynamics and is biotransformed by CYP1A1 into CEU-638, its potent antimicrotuble counterpart. Structure-activity relationships related to PAIB-SOs and PAIB-SAs evidenced that PAIB-SOs and PAIB-SAs are true bioisosteric equivalents fully and selectively activatable by CYP1A-expressing cells into potent antimitotics.
Topics: Antimitotic Agents; Antineoplastic Agents; Breast Neoplasms; Cell Proliferation; Cells, Cultured; Cytochrome P-450 CYP1A1; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Female; Humans; Molecular Structure; Prodrugs; Structure-Activity Relationship
PubMed: 30201525
DOI: 10.1016/j.bmc.2018.09.001 -
Scientific Reports Jun 2018Both classic and newer antimitotics commonly induce a prolonged mitotic arrest in cell culture. During arrest, cells predominantly undergo one of two fates: cell death...
Both classic and newer antimitotics commonly induce a prolonged mitotic arrest in cell culture. During arrest, cells predominantly undergo one of two fates: cell death by apoptosis, or mitotic slippage and survival. To refine this binary description, a quantitative understanding of these cell responses is needed. Herein, we propose a quantitative description of the kinetics of colon carcinoma RKO cell fates in response to different antimitotics, using data from the single cell experiments of Gascoigne and Taylor (2008). The mathematical model is calibrated using the in vitro experiments of Gascoigne and Taylor (2008). We show that the time-dependent probability of cell death or slippage is universally identical for monastrol, nocodazole and two different doses of AZ138, but significantly different for taxol. Death and slippage responses across drugs can be characterized by Gamma distributions. We demonstrate numerically that these rates increase with prolonged mitotic arrest. Our model demonstrates that RKO cells exhibit a triphasic response - first, remain in mitosis, then undergo fast and slow transition, respectively- dependent on the length of mitotic arrest and irrespective of cell fate, drug type or dose.
Topics: Antimitotic Agents; Apoptosis; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Survival; Colonic Neoplasms; Humans; Mitosis
PubMed: 29895957
DOI: 10.1038/s41598-018-27267-7 -
Cancer Letters Jan 2019Current microtubule-targeting agents (MTAs) remain amongst the most important antimitotic drugs used against a broad range of malignancies. By perturbing spindle... (Review)
Review
Current microtubule-targeting agents (MTAs) remain amongst the most important antimitotic drugs used against a broad range of malignancies. By perturbing spindle assembly, MTAs activate the spindle assembly checkpoint (SAC), which induces mitotic arrest and subsequent apoptosis. However, besides toxic side effects and resistance, mitotic slippage and failure in triggering apoptosis in various cancer cells are limiting factors of MTAs efficacy. Alternative strategies to target mitosis without affecting microtubules have, thus, led to the identification of small molecules, such as those that target spindle Kinesins, Aurora and Polo-like kinases. Unfortunately, these so-called second-generation of antimitotics, encompassing mitotic blockers and mitotic drivers, have failed in clinical trials. Our recent understanding regarding the mechanisms of cell death during a mitotic arrest pointed out apoptosis as the main variable, providing an opportunity to control the cell fates and influence the effectiveness of antimitotics. Here, we provide an overview on the second-generation of antimitotics, and discuss possible strategies that exploit SAC activity, mitotic slippage/exit and apoptosis induction, in order to improve the efficacy of anticancer strategies that target mitosis.
Topics: Animals; Antimitotic Agents; Antineoplastic Agents; Humans; Mitosis; Neoplasms
PubMed: 30312726
DOI: 10.1016/j.canlet.2018.10.005 -
Bioorganic & Medicinal Chemistry Feb 2015Microtubules are polar cytoskeletal filaments assembled from head-to-tail and comprised of lateral associations of α/β-tubulin heterodimers that play key role in... (Review)
Review
Microtubules are polar cytoskeletal filaments assembled from head-to-tail and comprised of lateral associations of α/β-tubulin heterodimers that play key role in various cellular processes. Because of their vital role in mitosis and various other cellular processes, microtubules have been attractive targets for several disease conditions and especially for cancer. Antitubulin is the most successful class of antimitotic agents in cancer chemotherapeutics. The target recognition of antimitotic agents as a ligand is not much explored so far. However, 3,4,5-trimethoxyphenyl fragment has been much highlighted and discussed in such type of interactions. In this review, some of the most important naturally occurring antimitotic agents and their interactions with microtubules are discussed with a special emphasis on the role of 3,4,5-trimethoxyphenyl unit. At last, some emerging naturally occurring antimitotic agents have also been tabulated.
Topics: Animals; Anisoles; Antimitotic Agents; Humans; Microtubules; Molecular Structure; Structure-Activity Relationship; Tubulin; Tubulin Modulators
PubMed: 25564377
DOI: 10.1016/j.bmc.2014.12.027 -
Microbial Pathogenesis Sep 2017Zinc oxide nanoparticles synthesized through eco-friendly approach has gained importance among researchers due to its broad applications. In the present work, hexagonal...
Zinc oxide nanoparticles synthesized through eco-friendly approach has gained importance among researchers due to its broad applications. In the present work, hexagonal wurtzite shape nanoparticles (below 100 nm size) were obtained using aqueous leaf extract of Cochlospermum religiosum which was confirmed through X-Ray diffraction (XRD) analysis. The synthesized ZnO-NPs showed an absorption peak at 305 nm which is one of the characteristic features of ZnO-NPs.The bio-fabricated ZnO-NPs were of high purity with an average size of ∼76 nm analyzed through Dynamic Light Scattering (DLS) analysis supporting the findings of XRD. The SEM images confirmed the same with agglomeration of smaller nanoparticles. The composition of aqueous leaf extract and ZnO-NPs was explored with Fourier Transform Infrared Spectroscopy (FT-IR). The plant extract as well as bio-fabricated ZnO-NPs offered significant inhibition against Gram-positive (B. subtilis and Staph. aureus) and Gram-negative (P. aeruginosa and E. coli) bacteria. The minimum inhibitory concentration (MIC) of bio-fabricated ZnO-NPs and plant extract was found between 4.8 and 625 μg/ml against test pathogens, which was authenticated with live and dead cell analysis. Apart from antibacterial potentiality, antimitotic activity was also observed with a mitotic index of 75.42% (ID 0.40 μg mL) and 61.41% (ID 0.58 μg mL) in ZnO-NPs and plant extract, respectively. The results affirm that plant extract and its mediated ZnO-NPs possess biological properties.
Topics: Allium; Anti-Bacterial Agents; Antimitotic Agents; Bixaceae; Cell Proliferation; Gram-Negative Bacteria; Gram-Positive Bacteria; Microbial Sensitivity Tests; Microscopy, Electron, Scanning; Nanoparticles; Plant Cells; Plant Extracts; Plant Leaves; X-Ray Diffraction; Zinc Oxide
PubMed: 28778822
DOI: 10.1016/j.micpath.2017.07.051 -
Chemical Biology & Drug Design Mar 2011In the present study, Autodock 4.0 was employed to discover potential carbonic anhydrase IX inhibitors that are able to interfere with microtubule dynamics by binding to...
In the present study, Autodock 4.0 was employed to discover potential carbonic anhydrase IX inhibitors that are able to interfere with microtubule dynamics by binding to the Colchicine binding site of tubulin. Modifications at position 2' of estrone were made to include moieties that are known to improve the antimitotic activity of estradiol analogs. 2-ethyl-3-O-sulphamoyl-estra-1,3,5(10),15-tetraen-3-ol-17-one estronem (C9) and 2-ethyl-3-O-sulphamoyl-estra-1,3,5(10)16-tetraene (C12) were synthesized and tested in vitro. Growth studies were conducted utilizing spectrophotometrical analysis with crystal violet as DNA stain. Compounds C9 and C12 were cytotoxic in MCF-7 and MDA-MB-231 tumorigenic and metastatic breast cancer cells, SNO non-keratinizing squamous epithelium cancer cells and HeLa cells after 48 h exposure. Compounds C9 inhibited cell proliferation to 50% of the vehicle-treated controls from 110 to 160 nm and C12 at concentrations ranging from 180 to 220 nm. Confocal microscopy revealed abnormal spindle morphology in mitotic cells. Cell cycle analysis showed an increase in the number of cells in the G(2) /M fraction after 24 h and an increase in the number of cell in the sub-G(1) fraction after 48 h, indicating that the compounds are antimitotic and able to induce apoptosis.
Topics: Antigens, Neoplasm; Antimitotic Agents; Binding Sites; Breast Neoplasms; Carbonic Anhydrase II; Carbonic Anhydrase IX; Carbonic Anhydrase Inhibitors; Carbonic Anhydrases; Cell Division; Cell Line, Tumor; Colchicine; Computer Simulation; Drug Design; Estrone; Female; G2 Phase; Humans; Software; Tubulin
PubMed: 21244635
DOI: 10.1111/j.1747-0285.2010.01064.x -
MBio Oct 2022The fungus Rhizopus microsporus harbors a bacterial endosymbiont () for the production of the antimitotic toxin rhizoxin. Although rhizoxin is the causative agent of...
The fungus Rhizopus microsporus harbors a bacterial endosymbiont () for the production of the antimitotic toxin rhizoxin. Although rhizoxin is the causative agent of rice seedling blight, the toxinogenic bacterial-fungal alliance is, not restricted to the plant disease. It has been detected in numerous environmental isolates from geographically distinct sites covering all five continents, thus raising questions regarding the ecological role of rhizoxin beyond rice seedling blight. Here, we show that rhizoxin serves the fungal host in fending off protozoan and metazoan predators. Fluorescence microscopy and coculture experiments with the fungivorous amoeba revealed that ingestion of R. microsporus spores is toxic to . This amoebicidal effect is caused by the dominant bacterial rhizoxin congener rhizoxin S2, which is also lethal toward the model nematode Caenorhabditis elegans. By combining stereomicroscopy, automated image analysis, and quantification of nematode movement, we show that the fungivorous nematode Aphelenchus avenae actively feeds on R. microsporus that is lacking endosymbionts, whereas worms coincubated with symbiotic R. microsporus are significantly less lively. This study uncovers an unexpected ecological role of rhizoxin as shield against micropredators. This finding suggests that predators may function as an evolutionary driving force to maintain toxin-producing endosymbionts in nonpathogenic fungi. The soil community is a complex system characterized by predator-prey interactions. Fungi have developed effective strategies to defend themselves against predators. Understanding these strategies is of critical importance for ecology, medicine, and biotechnology. In this study, we shed light on the defense mechanisms of the phytopathogenic - symbiosis that has spread worldwide. We report an unexpected role of rhizoxin, a secondary metabolite produced by the bacterium residing within the hyphae of R. microsporus. We show that this bacterial secondary metabolite is utilized by the fungal host to successfully fend off fungivorous protozoan and metazoan predators and thus identified a fundamentally new function of this infamous cytotoxic compound. This endosymbiont-dependent predator defense illustrates an unusual strategy employed by fungi that has broader implications, since it may serve as a model for understanding how animal predation acts as an evolutionary driving force to maintain endosymbionts in nonpathogenic fungi.
Topics: Animals; Burkholderia; Antimitotic Agents; Macrolides; Symbiosis; Oryza; Toxins, Biological; Seedlings; Soil
PubMed: 36005392
DOI: 10.1128/mbio.01440-22 -
Pharmacology & Therapeutics May 2017Mutations in cancer cells frequently result in cell cycle alterations that lead to unrestricted growth compared to normal cells. Considering this phenomenon, many drugs... (Review)
Review
Mutations in cancer cells frequently result in cell cycle alterations that lead to unrestricted growth compared to normal cells. Considering this phenomenon, many drugs have been developed to inhibit different cell-cycle phases. Mitotic phase targeting disturbs mitosis in tumor cells, triggers the spindle assembly checkpoint and frequently results in cell death. The first anti-mitotics to enter clinical trials aimed to target tubulin. Although these drugs improved the treatment of certain cancers, and many anti-microtubule compounds are already approved for clinical use, severe adverse events such as neuropathies were observed. Since then, efforts have been focused on the development of drugs that also target kinases, motor proteins and multi-protein complexes involved in mitosis. In this review, we summarize the major proteins involved in the mitotic phase that can also be targeted for cancer treatment. Finally, we address the activity of anti-mitotic drugs tested in clinical trials in recent years.
Topics: Animals; Antimitotic Agents; Antineoplastic Agents; Drug Design; Humans; Mitosis; Molecular Targeted Therapy; Mutation; Neoplasms
PubMed: 28174095
DOI: 10.1016/j.pharmthera.2017.02.007 -
BioDrugs : Clinical Immunotherapeutics,... 2007Basic research that has focused on achieving a mechanistic understanding of mitosis has provided unprecedented molecular and biochemical insights into this highly... (Review)
Review
Basic research that has focused on achieving a mechanistic understanding of mitosis has provided unprecedented molecular and biochemical insights into this highly complex phase of the cell cycle. The discovery process has uncovered an ever-expanding list of novel proteins that orchestrate and coordinate spindle formation and chromosome dynamics during mitosis. That many of these proteins appear to function solely in mitosis makes them ideal targets for the development of mitosis-specific cancer drugs. The clinical successes seen with anti-microtubule drugs such as taxanes and the vinca alkaloids have also encouraged the development of drugs that specifically target mitosis. Drugs that selectively inhibit mitotic kinesins involved in spindle and kinetochore functions, as well as kinases that regulate these activities, are currently in various stages of clinical trials. Our increased understanding of mitosis has also revealed that this process is targeted by inhibitors of farnesyl transferase, histone deacetylase, and Hsp90. Although these drugs were originally designed to block cell proliferation by inhibiting signaling pathways and altering gene expression, it is clear now that these drugs can also directly interfere with the mitotic process. The increased attention to mitosis as a chemotherapeutic target has also raised an important issue regarding the cellular determinants that specify drug sensitivity. One likely contribution is the mitotic checkpoint, a failsafe mechanism that delays mitotic exit so that cells whose chromosomes are not properly attached to the spindle have extra time to correct their errors. As the biochemical activity of the mitotic checkpoint is finite, cells cannot indefinitely sustain the delay, as in cases where cells are treated with anti-mitotic drugs. When the mitotic checkpoint activity is eventually lost, cells will exit mitosis and become aneuploid. While many of the aneuploid cells may die because of massive chromosome imbalance, survivors that continue to proliferate will no doubt be selected. This is clearly an undesirable outcome, thus efforts to obtain fundamental insights into why some cells that arrest in mitosis die without exiting mitosis will be exceedingly important in enhancing our understanding of the drug sensitivity of cancer cells.
Topics: Animals; Antimitotic Agents; Farnesyltranstransferase; HSP90 Heat-Shock Proteins; Humans; Kinesins; Kinetochores; Microtubules; Mitosis; Neoplasms; Protein Kinase Inhibitors
PubMed: 17628120
DOI: 10.2165/00063030-200721040-00003