Benserazide Perturbs Kif15‐kinesin Binding Protein Interaction with Prolonged Metaphase and Defects in Chromosomal Congression: A Study Based on in silico Modeling and Cell Culture

The Application of Kinesin Inhibitors in Medical Issues

Kinesins are a group of motor proteins in charge of several crucial functions in the cell. These proteins often bind to microtubules and perform their functions using the energy produced by ATP hydrolysis. One function of mitotic kinesin, a subclass of kinesin that is expressed during cell division at the mitotic phase, is to create the mitotic spindle. Uncontrolled cell growth is one trait of cancerous cells. Traditional anticancer medications still used in clinics include taxanes (paclitaxel) and vinca alkaloids (vincristine, vinblastine), which interfere with microtubule dynamics. However, because non-dividing cells like post-mitotic neurons contain microtubules, unwanted side effects like peripheral neuropathy are frequently found in patients taking these medications. More than ten members of the mitotic kinesin family play distinct or complementary roles during mitosis. The mitotic kinesin family's KSP, or Eg5, is regarded as its most dramatic target protein. The current work systematically reviews the use of kinesin inhibitors in the medical field. The challenges of KSP and the practical solutions are also examined, and the outcomes of the previous works are reported. The significant gaps and shortcomings of the related works are also highlighted, which can be an onset topic for future works.

Cytotoxic mechanism of tioconazole involves cell cycle arrest at mitosis through inhibition of microtubule assembly

Tioconazole is one of the drugs used to treat topical mycotic infections. It exhibited severe toxicity during systemic administration; however, the molecular mechanism behind the cytotoxic effect was not well established. We employed HeLa cells as a model to investigate the molecular mechanism of its toxicity and discovered that tioconazole inhibited HeLa cell growth through mitotic block (37%). At the half-maximal inhibitory concentration (≈ 15 μM) tioconazole apparently depolymerized microtubules and caused defects in chromosomal congression at the metaphase plate. Tioconazole induced apoptosis and significantly hindered the migration of HeLa cells. Tioconazole bound to goat brain tubulin (K _d, 28.3 ± 0.5 μM) and inhibited the assembly of microtubules in the in vitro assays. We report for the first time that tioconazole binds near to the colchicine site, based on the evidence from in vitro tubulin competition experiment and computational analysis. The conformation of tubulin dimer was found to be "curved" upon binding with tioconazole in the MD simulation. Tioconazole in combination with vinblastine synergistically inhibited the growth of HeLa cells and augmented the percentage of mitotic block by synergistically inhibiting the assembly of microtubules. Our study indicates that the systemic adverse effects of tioconazole are partly due to its effects on microtubules and cell cycle arrest. Since tioconazole is well tolerated at the topical level, it could be developed as a topical anticancer agent in combination with other systemic anticancer drugs.

GRAPHICAL ABSTRACT

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s10616-021-00516-w.

BAPST. A Combo of Common use drugs as metabolic therapy of cancer-a theoretical proposal

Advances in cancer therapy have yet to impact worldwide cancer mortality. Poor cancer drug affordability is one of the factors limiting mortality burden strikes. Up to now, cancer drug repurposing had no meet expectations concerning drug affordability. The three FDA-approved cancer drugs developed under repurposing -all-trans-retinoic acid, arsenic trioxide, and thalidomide- do not differ in price from other drugs developed under the classical model. Though additional factors affect the whole process from inception to commercialization, the repurposing of widely used, commercially available, and cheap drugs may help. This work reviews the concept of the malignant metabolic phenotype and its exploitation by simultaneously blocking key metabolic processes altered in cancer. We elaborate on a combination called BAPST, which stands for the following drugs and pathways they inhibit: Benserazide (glycolysis), Apomorphine (glutaminolysis), Pantoprazole (Fatty-acid synthesis), Simvastatin (mevalonate pathway), and Trimetazidine (Fatty-acid oxidation). Their respective primary indications are: • Parkinson's disease (benserazide and apomorphine). • Peptic ulcer disease (pantoprazole). • Hypercholesterolemia (simvastatin). • Ischemic heart disease (trimetazidine). When used for their primary indication, the literature review on each of these drugs shows they have a good safety profile and lack predicted pharmacokinetic interaction among them. Most importantly, the inhibitory enzymatic concentrations required for inhibiting their cancer targets enzymes are below the plasma concentrations observed when these drugs are used for their primary indication. Based on that, we propose that the regimen BAPTS merits preclinical testing.

Sertaconazole induced toxicity in HeLa cells through mitotic arrest and inhibition of microtubule assembly

Econazole, miconazole, and sertaconazole, the structurally related azoles with imidazole moiety, were evaluated for their cytotoxicity and their ability to bind to mammalian tubulin. Our results indicated that sertaconazole and econazole bound to goat brain tubulin with a dissociation constant of 9 and 19 μM respectively, while miconazole did not bind to goat brain tubulin. Econazole, miconazole, and sertaconazole inhibited the proliferation of HeLa cells with an IC₅₀ of 28, 98, and 38 μM respectively with sertaconazole alone inducing a mitotic block in the treated cells. Since sertaconazole bound to goat brain tubulin with higher affinity and blocked the cells at mitosis, we hypothesized that its cytotoxic mechanism might involve inhibition of tubulin and econazole which did not block the cells at mitosis may have additional targets than tubulin. Sertaconazole inhibited the polymerization of tubulin in HeLa cells and the in vitro assembled goat brain tubulin. Competitive tubulin-binding assay using colchicine and computational simulation studies showed that sertaconazole bound closer to the colchicine site and induced the tubulin dimer to adopt a "bent" conformation which is incompetent for the polymerization. Results from RT-PCR analysis of the A549 cells treated with sertaconazole indicated activation of apoptosis. Sertaconazole significantly inhibited the migration of HeLa cells and showed synergistic antiproliferative potential with vinblastine. Collectively, the results suggest that sertaconazole which is already in clinical practice could be useful as a topical chemotherapy agent for the treatment of skin cancers in combination with other systemic anticancer agents.

Eg5 targeting agents: From new anti-mitotic based inhibitor discovery to cancer therapy and resistance

Eg5, the product of Kif11 gene, also known as kinesin spindle protein, is a motor protein involved in the proper establishment of a bipolar mitotic spindle. Eg5 is one of the 45 different kinesins coded in the human genome of the kinesin motor protein superfamily. Over the last three decades Eg5 has attracted great interest as a promising new mitotic target. The identification of monastrol as specific inhibitor of the ATPase activity of the motor domain of Eg5 inhibiting the Eg5 microtubule motility in vitro and in cellulo sparked an intense interest in academia and industry to pursue the identification of novel small molecules that target Eg5 in order to be used in cancer chemotherapy based on the anti-mitotic strategy. Several Eg5 inhibitors entered clinical trials. Currently the field is faced with the problem that most of the inhibitors tested exhibited only limited efficacy. However, one Eg5 inhibitor, Arry-520 (clinical name filanesib), has demonstrated clinical efficacy in patients with multiple myeloma and is scheduled to enter phase III clinical trials. At the same time, new trends in Eg5 inhibitor research are emerging, including an increased interest in novel inhibitor binding sites and a focus on drug synergy with established antitumor agents to improve chemotherapeutic efficacy. This review presents an updated view of the structure and function of Eg5-inhibitor complexes, traces the possible development of resistance to Eg5 inhibitors and their potential therapeutic applications, and surveys the current challenges and future directions of this active field in drug discovery.