spindles

Phenytoin (5,5-Diphenylhydantoin) is a hydantoin derivative and a non-sedative antiepileptic agent with anticonvulsant activity. It potentially acts by promoting sodium efflux from neurons in the motor cortex, reducing post-tetanic potentiation at synapses. This prevents cortical seizure foci from spreading to adjacent areas and stabilizes the threshold against hyperexcitability. Additionally, it appears to reduce muscle spindle sensitivity to stretch, causing muscle relaxation.

Ciliobrevin D is a AAA+ ATPase motor cytoplasmic dynein inhibitor. Ciliobrevin D inhibits Hedgehog (Hh) signaling and primary cilia formation and it also inhibits dynein-dependent microtubule gliding and ATPase activity in vitro.

Indibulin (D 24851) is a synthetic small molecule with antimitotic and potential antineoplastic activities.Indibulin an orally applicable inhibitor of tubulin assembly, shows potent anticancer activity with a minimal neurotoxicity. Indibulin reduces inter-kinetochoric tension, produces aberrant spindles, activates mitotic checkpoint proteins Mad2 and BubR1, and induces mitotic arrest and apoptosis.

Dimethylenastron, an Eg5 inhibitor, arrests cells with monopolar spindles to which all chromosomes attach in a syntelic manner.

Solidagonic acid, by inhibiting HSET motor activity, promotes the conversion of abnormal monopolar spindles to bipolar configurations, effectively suppressing fission yeast cell death and facilitating the mitotic spindles' reversion from monopolar to bipolar morphology. Additionally, this compound demonstrates growth inhibitory effects on the seedlings of Lactuca sativa L. and Lolium multiflorum Lam [1] [2].

4SC-207 is a novel microtubule inhibitor , which shows strong anti-proliferative activity in a large panel of tumor cell lines with an average GI50 of 11 nM. In particular, 4SC-207 is active in multi-drug resistant cell lines, such as HCT-15 and ACHN, suggesting that it is a poor substrate for drug efflux pumps. 4SC-207 inhibits microtubule growth in vitro and in vivo and promotes, in a dose dependent manner, a mitotic delay/arrest, followed by apoptosis or aberrant divisions due to chromosome alignment defects and formation of multi-polar spindles. Furthermore, preliminary data from preclinical studies suggest low propensity towards bone marrow toxicities at concentrations that inhibit tumor growth in paclitaxel-resistant xenograft models. 4SC-207 may be a potential anti-cancer agent.

Microtubule stabilizing agent. Potent inhibitor of cellular proliferation in cancer cell lines (IC50 reported to be 3-30 nM, dependent on cell line used). Causes cells to arrest in the prometaphase of the cell cycle, prevents formation of bipolar spindle and increases kinetochore tension in preformed spindles. Pryor et al (2002) The microtubule stabilizing agent laulimalide does not bind in the taxoid site, kills cells resistant to PacT. and epothilones, and may not require its epoxide moiety for activity. Biochemistry. 41 9109 PMID:12119025 |Bennett et al (2012) Low-dose laulimalide represents a novel molecular probe for investigating microtubule organization. Cell Cycle. 11 3045 PMID:22871740 |Bennett et al (2010) Discovery and characterization of the laulimalide-microtubule binding mode by mass shift perturbation mapping. Chem.Biol. 17 725 PMID:20659685

AZD4877 is a synthetic kinesin spindle protein (KSP) inhibitor with potential antineoplastic activity. KSP inhibitor AZD4877 selectively inhibits microtubule motor protein KSP (also called kinesin-5 or Eg5), which may result in the inhibition of mitotic spindle assembly; activation of the spindle assembly checkpoint; induction of cell cycle arrest during the mitotic phase; and cell death in tumor cells that are actively dividing. Because KSP is not involved in postmitotic processes, such as neuronal transport, this agent may be less likely to cause the peripheral neuropathy often associated with the tubulin-targeting agents. Eg5 is essential for the formation of bipolar spindles and the proper segregation of sister chromatids during mitosis.

DAP-81 is a diaminopyrimidine derivative that targets PLKs, destabilizing kinetochore microtubules. Other spindle tubules are stabilized, resulting in monopolar mitotic spindles. In vitro, DAP-81 inhibits Plk1 at an IC50 of 0.9 nM. DAP-81 is currently in ongoing preclinical evaluations.

DAT-230 is a promising microtubule inhibitor that has great potential for the treatment of fibrosarcoma in vitro and in vivo. DAT-230 exhibited potent anti-proliferative activity against various cancer cells. DAT-230 -treatment in HT-1080 cells resulted in microtubule de-polymerization and G2/M phase arrest preceding apoptosis. Phosphor-cdc2 (thr14/tyr15) reduction, cyclin B1 accumulation and aberrant spindles denoted the cyclin B1-cdc2 complex active and M phase arrest in HT-1080 cells treated with DAT-230. Apoptosis induced by DAT-230 was related with the activation of caspase-9, caspase-3 and PARP cleavage, which were at the downstream of mitochondria.