Small molecule inhibitor of mitotic spindle bipolarity identified in a phenotype-based screen

Targeting Eg5 using Arry520 combats gastric cancer by inducing monopolar spindles

Eg5, also known as KIF11, is a motor protein essential for establishing a bipolar spindle and ensuring proper chromosome congression during mitosis. It is amplified in various human cancers and serves as a critical oncogene driving tumour progression. However, the role and clinical significance of Eg5 in gastric cancer has remained elusive. In this study, we showed that Eg5 is upregulation in gastric cancer tissues and is negatively associated with patient prognosis. The ablation of Eg5 inhibits the proliferation and migration of gastric cancer cells and suppresses tumour growth in xenograft mice. Mechanistically, Eg5 ablation induces the formation of monopolar spindle, leading to cell apoptosis and consequent inhibition of tumour growth. Furthermore, Arry520 is demonstrated as a potent Eg5 inhibitor which blocks tumour growth by increasing the formation of cell monopolar spindle and inducing apoptosis. Arry520 exhibits efficiently therapeutic effects on gastric cancer in tumour organoid models, cell-derived xenografts and patient-derived xenografts (PDX) in mice. Collectively, our findings provide evidence for the oncogenic properties of the mitotic protein Eg5 and identify Arry520 as a promising strategy to combat gastric cancer.

The Liebeskind-Srogl cross-coupling reaction towards the synthesis of biologically active compounds

In this review, we emphasize the significance of the Liebeskind-Srogl cross-coupling reaction, a palladium-catalyzed process involving the reaction between a thioester and a boronic acid. This reaction has emerged as a fundamental technique in synthetic methodologies aimed at the development of biologically active compounds. The Liebeskind-Srogl cross-coupling method has become an essential approach in chemistry, facilitating the diversification of complex structures that would be significantly more challenging to synthesize through alternative approaches. In this review, we aim to outline the numerous possibilities for preparing a wide range of derivatives, each with notable biological potential.

Synthesis of dihydropyrimidinones via urea-based multicomponent reactions

Multicomponent reactions (MCRs) have emerged as powerful tools in organic chemistry, enabling the rapid and efficient assembly of complex molecular architectures. Urea-based multicomponent reactions have gained significant attention due to their versatility and broad applicability. In this review, we highlight recent developments in this area, with a focus on dihydropyrimidinones, and provide an in-depth analysis of the diverse synthetic pathways and applications of urea-based MCRs, shedding light on their fundamental mechanisms, reaction conditions, and potential for green and sustainable synthesis.

A stress-responsive p38 signaling axis in choanoflagellates

Animal kinases regulate cellular responses to environmental stimuli, including cell differentiation, migration, survival, and response to stress, but the ancestry of these functions is poorly understood. Choanoflagellates, the closest living relatives of animals, encode homologs of diverse animal kinases and have emerged as model organisms for reconstructing animal origins. However, efforts to identify key kinase regulators in choanoflagellates have been constrained by the limitations of currently available genetic tools. Here, we report on a framework that combines small molecule-driven kinase discovery with targeted genetics to reveal kinase function in choanoflagellates. To study the physiological roles of choanoflagellate kinases, we established two high-throughput platforms to screen the model choanoflagellate Salpingoeca rosetta with a curated library of human kinase inhibitors. We identified 95 diverse kinase inhibitors that disrupt S. rosetta cell proliferation. By focusing on one inhibitor, sorafenib, we identified a p38 kinase as a regulator of the heat shock response in S. rosetta. This finding reveals a conserved p38 function between choanoflagellates, animals, and fungi. Moreover, this study demonstrates that existing kinase inhibitors can serve as powerful tools to examine the ancestral roles of kinases that regulate modern animal development.

Design, synthesis and biological evaluation of new class of pyrazoles-dihydropyrimidinone derivatives as bone anabolic agents

This study explores a series of twenty-four newly synthesized pyrzole-dihydropyrimidinone hybrids as potential bone anabolic agents. Initially, an alkaline phosphatase assay, a common marker of bone formation, was used to screen all compounds for their ability to stimulate osteogenic potential. Initial screening identified three promising candidates (5f, 5u and 5w) that were subsequently confirmed to be non-toxic to osteoblasts. Further investigation revealed that compound 5w displayed the most potent osteoanabolic effect, promoting osteoblast differentiation and upregulating mRNAs expression of osteogenic gene. Based on the promising in vitro and in vivo activity, structure-activity relationship (SAR) analysis revealed a furan ring on the dihydropyrimidinone unit and electron-donating groups on the N-phenyl ring of the pyrazole moiety to be crucial for osteogenic activity. Additionally, molecular docking, favorable pharmacokinetic properties and In silico ADME predictions suggest potential oral bioavailability. These findings establish the pyrazole-dihydropyrimidinone scaffold as a promising hit for developing a new class of orally active bone anabolic agents.

KIF11 Inhibition Induces Retinopathy Progression by Affecting Photoreceptor Cell Ciliogenesis and Cell Cycle Regulation in Development

Microcephaly with or without chorioretinopathy, lymphedema, or impaired intellectual development (MCLMR; OMIM 152950) is a rare autosomal dominant disorder, which is primarily characterized by defects in the central nervous system and retinal developmental anomalies. Kinesin-5 KIF11 has been discovered as a major causative gene for MCLMR. It has been well established that KIF11 is essential for microtubule organization, centrosome separation, and spindle assembly during mitosis. However, cellular and molecular mechanisms in the physiopathology of MCLMR remain largely unknown. In this study, KIF11-inhibition mouse models are generated, which reveal that chemical inhibition of KIF11 results in defects in retinal development, the formation of rosettes, photoreceptor ciliary alterations, and vision loss. Furthermore, it is demonstrated that KIF11 is essential for the formation, organization, and maintenance of primary cilia in photoreceptor cells, which further contributes to the organization of photoreceptor cells and the development of the retina. Using the developing mouse embryos as a model, it is revealed that KIF11 inhibition induces the formation of monopolar spindle and mitotic arrest, which further results in tetraploidy and apoptotic cell death. These findings uncover cellular mechanisms underlying the loss-of-function of KIF11 and retinopathy in MCLMR and further support the functions of KIF11 in development.

Green synthesis of new adamantane-containing dihydropyrimidine derivatives as potential anticancer agents

Despite significant progress in cancer treatment, cancer remains a major focus of research due to medication resistance and side effects. In this study, bioactive adamantane-containing dihydropyrimidine (DHPM) derivatives were synthesized through the multi-component Biginelli reaction of N-(adamant-1-yl)acetoacetamide, benzaldehyde derivatives, and thiourea in the presence of trifluoroacetic acid (TFA, 2 mol%) as catalyst under solvent free conditions. This method provides an effective and significantly improved modification of the original Biginelli reaction in terms of yield and reaction time. The synthesized DHPM derivatives were subjected to cytotoxicity screening against the A-549 human non-small cell lung cancer (NSCLC) cell line to evaluate their effects on cell growth inhibition. MTT cytotoxicity assay was used to determine IC50 values. Among the target analogs, IIb, IIj, IId, and IIg demonstrated the best activity with IC50 values of 1.03, 8.36, 10.38, and 16.04 μg mL-1, respectively. Additionally, we assessed the possible mechanisms for cell growth inhibition and induction of apoptotic cell death using the DAPI and Annexin V-FITC staining. The average percentages of apoptotic cells were 21.35%, 28.35%, 32.73, and 43.33% for IIg, IId, IIj, and IIb treatment groups, respectively. These results suggest that the synthesized adamantane-containing dihydropyrimidines can be considered as encouraging molecules for further drug development as anticancer agents.

QSAR, Antimicrobial, and Antiproliferative Study of (R/S)-2-Thioxo-3,4-dihydropyrimidine-5-carboxanilides

Owing to the significant contribution of three-dimensional (3D) field-based QSAR toward hit optimization and accurately predicting the activities of small molecules, herein, the 3D-QSAR, in vitro antimicrobial, molecular docking, and pharmacophore modeling studies of all the isolated (R/S)-2-thioxo-DHPM-5-carboxanilides exhibiting antimicrobial activity were carried out. The screening process was performed using 46 compounds, and the best-scoring model with the top statistical values was considered for bacterial and fungal targets Bacillus subtilis and Candida albicans. As a result of 3D-QSAR analysis, compound 4v-(S)- and 4v-(R)-isomers were found to be more potent compared to the standard drugs tetracycline and fluconazole, respectively. Furthermore, the enantiomerically pure isomers 4q, 4d', 4n, 4f', 4v, 4q', 4c, and 4p' were found to be more potent than tetracycline and fluconazole to inhibit the bacterial and fungal growth against B. subtilis, Salinivibrio proteolyticus, C. albicans, and Aspergillus niger, respectively. Molecular docking analysis shows that with the glide score of -10.261 kcal/mol, 4v-(R)-isomer was found to be more potent against the fungal target C. albicans and may target the 14-α demethylase than fluconazole. Furthermore, all compounds' antiproliferative activity results showed that 4o' exhibited GI50 values between 8.8 and 34 μM against six solid tumor cell lines. Following the greater potential of 4o' toward the HeLa cell line, its kinetics study and live cell imaging were carried out. These outcomes highlight the acceptance and safety as well as the potential of compounds as effective antiproliferative and antifungal agents.

Chemogenetic modulation of parathyroid hormone secretion alleviates osteoporosis in ovariectomized rats

Parathyroid hormone (PTH) is critical for regulating calcium and phosphate homeostasis, and its dysregulation contributes to osteoporosis. Current methods for precise control of PTH secretion are limited. This study explores chemogenetic tools to regulate PTH secretion in parathyroid chief cells via Gq/Gi signaling. In vitro, we found that activation of hM3Dq-expressing cells increased PTH release, while hM4Di inhibited it. In vivo, hM3Dq activation improved bone structure and reduced bone loss in an ovariectomized rat model. These findings suggest chemogenetics as a promising approach for modulating PTH and offering potential therapeutic strategies for bone health and related disorders.

Biological function and mechanism of NAT10 in cancer

N-acetyltransferase 10 (NAT10) is a nucleolar acetyltransferase with an acetylation catalytic function and can bind various protein and RNA molecules. As the N4-acetylcytidine (ac4C) "writer" enzyme, NAT10 is reportedly involved in a variety of physiological and pathological activities. Currently, the NAT10-related molecular mechanisms in various cancers are not fully understood. In this review, we first describe the cellular localization of NAT10 and then summarize its numerous biological functions. NAT10 is involved in various biological processes by mediating the acetylation of different proteins and RNAs. These biological functions are also associated with cancer progression and patient prognosis. We also review the mechanisms by which NAT10 plays roles in various cancer types. NAT10 can affect tumor cell proliferation, metastasis, and stress tolerance through its acetyltransferase properties. Further research into NAT10 functions and expression regulation in tumors will help explore its future potential in cancer diagnosis, treatment, and prognosis.

Mechanism and regulation of kinesin motors

Kinesins are a diverse superfamily of microtubule-based motors that perform fundamental roles in intracellular transport, cytoskeletal dynamics and cell division. These motors share a characteristic motor domain that powers unidirectional motility and force generation along microtubules, and they possess unique tail domains that recruit accessory proteins and facilitate oligomerization, regulation and cargo recognition. The location, direction and timing of kinesin-driven processes are tightly regulated by various cofactors, adaptors, microtubule tracks and microtubule-associated proteins. This Review focuses on recent structural and functional studies that reveal how members of the kinesin superfamily use the energy of ATP hydrolysis to transport cargoes, depolymerize microtubules and regulate microtubule dynamics. I also survey how accessory proteins and post-translational modifications regulate the autoinhibition, cargo binding and motility of some of the best-studied kinesins. Despite much progress, the mechanism and regulation of kinesins are still emerging, and unresolved questions can now be tackled using newly developed approaches in biophysics and structural biology.

Maternal ELL3 loss-of-function leads to oocyte aneuploidy and early miscarriage

Up to an estimated 10% of women experience miscarriage in their lifetimes. Embryonic aneuploidy is a leading cause for miscarriage, infertility and congenital defects. Here we identify variants of ELL3, a gene encoding a transcription elongation factor, in couples who experienced consecutive early miscarriages due to embryonic aneuploidy. Maternal ELL3 knockout leads to mouse oocyte aneuploidy, subfertility and miscellaneous embryonic defects. Mechanistically, we find that ELL3 localizes to the spindle during meiosis, and that ELL3 depletion in both mouse and human oocytes increases the incidence of meiotic spindle abnormality. ELL3 coordinates with TPX2 to ensure the proper function of the microtubule motor KIF11. Live imaging analysis shows that ELL3 is paramount for promoting spindle assembly and driving chromosome movement. Together, our findings implicate maternal ELL3 deficiency in causing oocyte aneuploidy and early miscarriage.

Decoding the Role of Kinesin Superfamily Proteins in Glioma Progression

Glioma is a highly aggressive and invasive brain tumor with limited treatment options, highlighting the need for novel therapeutic approaches. Kinesin superfamily proteins (KIFs) are a diverse group of motor proteins that play essential roles in cellular processes such as mitosis, intracellular transport, and signal transduction, all of which are crucial for tumorigenesis. This review focuses on the multifaceted role of KIFs in glioma, examining their clinical relevance, contribution to tumor progression, and potential as therapeutic targets. We discuss how KIFs influence key aspects of glioma biology, including cell proliferation, invasion, migration, and metastasis. Furthermore, we explore the regulation of the cell cycle and critical signaling pathways associated with glioma, such as PI3K-Akt, Wnt/β-catenin, and Hedgehog signaling by KIFs. The review also addresses the emerging interplay between KIFs and non-coding RNAs, including circular RNAs (circRNAs) and microRNAs (miRNAs), in glioma progression. Finally, we examine current therapeutic strategies targeting KIFs, including immunotherapy, chemotherapy, and small-molecule inhibitors, and their potential to improve treatment outcomes for glioma patients. By synthesizing these insights, this review underscores the significance of KIFs in glioma pathogenesis and their promise as novel therapeutic targets in the fight against glioma.

The Effects of Podophyllotoxin Derivatives on Noncancerous Diseases: A Systematic Review

Podophyllotoxin (PPT) is commonly used for genital warts due to its antimitotic properties and relatively good accessibility since it can be extracted from plants in low-economy countries. However, due to relatively high toxicity, it cannot be used in a systematic way (intravenously). Thus, there is a need to find or create an equally effective derivative of PPT that will be less toxic. Natural PPT is a suitable and promising scaffold for the synthesis of its derivatives. Many of them have been studied in clinical and preclinical models. In this systematic review, we comprehensively assess the medical applications of PPT derivatives, focusing on their advantages and limitations in non-cancerous diseases. Most of the existing research focuses on their applications in cancerous diseases, leaving non-cancerous uses underexplored. To do that, we systematically reviewed the literature using PubMed, Embase, and Cochrane databases from January 2013 to January 2025. In total, 5333 unique references were identified in the initial search, of which 44 were included in the quantitative synthesis. The assessment of the quality of eligible studies was undertaken using the PRISMA criteria. The risk of bias was assessed using a predefined checklist based on PRISMA guidelines. Each study was independently reviewed by two researchers to evaluate bias in study design, reporting, and outcomes. Our analysis highlights the broad therapeutic potential of PPT derivatives, particularly in antiviral applications, including HPV, Dengue, and SARS-CoV-2 infections. Apart from their well-known anti-genital warts activity, these compounds exhibit significant anti-inflammatory, antimitotic, analgesic, and radioprotective properties. For instance, derivatives such as cyclolignan SAU-22.107 show promise in antiviral therapies, while compounds like G-003M demonstrate radioprotective effects by mitigating radiation-induced damage. To build on this, our review highlights that PPT derivatives, apart from anti-genital warts potential, exhibit four key properties-anti-inflammatory, antimitotic, analgesic, and radioprotective-making them promising candidates not only for treating viral infections such as HPV, Dengue, and SARS-CoV-2 but also for expanding their therapeutic potential beyond cancerous diseases. In conclusion, while PPT derivatives hold great potential across various medical domains, their applications in non-cancerous diseases remain limited by the scarcity of dedicated research. Continued exploration of these compounds is essential to unlock their full therapeutic value.

Metal Ion Signaling in Biomedicine

Complex multicellular organisms are composed of distinct tissues involving specialized cells that can perform specific functions, making such life forms possible. Species are defined by their genomes, and differences between individuals within a given species directly result from variations in their genetic codes. While genetic alterations can give rise to disease-causing acquisitions of distinct cell identities, it is now well-established that biochemical imbalances within a cell can also lead to cellular dysfunction and diseases. Specifically, nongenetic chemical events orchestrate cell metabolism and transcriptional programs that govern functional cell identity. Thus, imbalances in cell signaling, which broadly defines the conversion of extracellular signals into intracellular biochemical changes, can also contribute to the acquisition of diseased cell states. Metal ions exhibit unique chemical properties that can be exploited by the cell. For instance, metal ions maintain the ionic balance within the cell, coordinate amino acid residues or nucleobases altering folding and function of biomolecules, or directly catalyze specific chemical reactions. Thus, metals are essential cell signaling effectors in normal physiology and disease. Deciphering metal ion signaling is a challenging endeavor that can illuminate pathways to be targeted for therapeutic intervention. Here, we review key cellular processes where metal ions play essential roles and describe how targeting metal ion signaling pathways has been instrumental to dissecting the biochemistry of the cell and how this has led to the development of effective therapeutic strategies.

Discovery of novel KSP-targeting PROTACs with potent antitumor effects in vitro and in vivo

Kinesin spindle protein (KSP) plays a crucial role during mitosis, making it an attractive target for cancer treatment. Herein, we report the design, synthesis, and evaluation of the first series of KSP degraders by using the utilization of the proteolysis-targeting chimera (PROTAC) technology. Compound 21 was identified as a potent KSP degrader with a DC50 (concentration causing 50 % of protein degradation) value of 114.8 nM and a Dmax (maximum degradation) of 90 % in the HCT-116 cells. Compound 21 showed strong antiproliferative activity against HCT-116 cells with an IC50 values of 10 nM. Mechanistic investigations revealed that 21 causes the cell arrest at the G2/M phase and subsequent cell apoptosis. In addition, 21 demonstrated more significant inhibition of tumor growth in an HCT-116 xenograft model compared to its parent compound 1. Our findings suggest that 21 may become the promising leads for further development.

Human REXO4 is Required for Cell Cycle Progression

Human REXO4 is a poorly characterized exonuclease that is overexpressed in human cancers. To better understand the function of REXO4 and its relationship to cellular proliferation, we have undertaken multidisciplinary approaches to characterize its cell cycle phase-dependent subcellular localization and the cis determinants required for this localization, its importance to cell cycle progression and cell viability, its protein-protein association network, and its activity. We show that the localization of REXO4 to the nucleolus in interphase depends on an N-terminal nucleolar localization sequence and that its localization to the perichromosomal layer of mitotic chromosomes is dependent on Ki67. Depletion of REXO4 led to a G1/S cell cycle arrest, and reduced cell viability. REXO4 associated with ribosome components and other proteins involved in rRNA metabolism. We propose a model where REXO4 is important for proper rRNA processing, which is required for ribosome biogenesis, cell cycle progression, and proliferation.

An "In Schizo" Evaluation System to Screen for Human Kinesin-5 Inhibitors

Kinesin-5 motor proteins are essential for mitotic spindle formation and maintenance, ensuring accurate chromosome segregation. Human kinesin-5 is highly expressed in various cancer cells but not in nonproliferative tissues; therefore, it is expected to be an attractive target for cancer chemotherapy, with fewer adverse side effects. Many inhibitors have been developed and subjected to clinical trials; however, they have not yet been commercially distributed because of their poor efficacy and frequent drug resistance. Establishing in vivo assay systems to easily monitor inhibitory activity is necessary and valuable to develop more effective inhibitors. Here, we report a procedure to evaluate the inhibitory activity against human kinesin-5 using a fission yeast-based system called "in schizo". Our approach could further be used to screen for inhibitors against kinesin-5 and other human cancer-related targets.

Precision in stereochemistry: the integral role of catalytic asymmetric Biginelli reaction in crafting enantiomerically pure dihydropyrimidinones

One well-known multicomponent reaction that is helpful in the synthesis of dihydropyrimidinones (DHPMs), important molecules in organic synthesis and medicinal chemistry, is the Biginelli reaction. Because of their wide range of biological activities, DHPMs are regarded as essential chemicals. A great deal of research has been done in the last few decades to find ways to produce enantiomerically pure DHPMs because of their notable and focused target-oriented biological activities. In this reaction, numerous structural variants and catalysts have been employed in a range of solvents to yield an enormous number of Biginelli-type compounds. In the present review, the available catalysts in the literature including ionic liquids, Lewis acids, and organocatalysts for the Biginelli reaction and synthesis of a large number of asymmetric compounds since 2003 are summarized.

Elraglusib Induces Cytotoxicity via Direct Microtubule Destabilization Independently of GSK3 Inhibition

SIGNIFICANCE

Elraglusib was designed as a GSK3 inhibitor and is currently in clinical trials for several cancers. We show conclusively that the target of elraglusib that leads to cytotoxicity is MTs and not GSK3. This has significant implications for ongoing clinical trials of the compound and will help in understanding off-target side effects, inform future clinical trial design, and facilitate the development of biomarkers to predict response.

DNA interaction of selected tetrahydropyrimidine and its effects against CCl4-induced hepatotoxicity in vivo: Part II

Tetrahydropyrimidine (compound A = methyl 4-[4'-(heptyloxy)-3'-methoxyphenyl]-1,6-dimethyl-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate) was chosen for in vivo studies after exhibiting noteworthy in vitro activity against the K562 and MDA-MB-231 cell lines, with IC50 values of 9.20 ± 0.14 µM and 12.76 ± 1.93 µM, respectively. According to experimental (fluorescence titration, viscosity, and differential scanning calorimetry) results, A interacts with DNA via the minor groove. In vivo, acute oral toxicity studies in Wistar albino rats proved no noticeable symptoms of either toxicity or death during the follow-up period. Genotoxic and antigenotoxic studies at three different concentrations of A (5, 10, and 20 mg/kg of body weight) in Wistar albino rats showed that the dose of 5 mg/kg body weight did not cause DNA damage and had a remarkable DNA protective activity against CCl4-induced DNA damage, with a percentage reduction of 78.7%. It is also important to note that, under the investigated concentrations of A, liver damage is not observed. Considering all experimental outcomes realized under various in vivo investigations (acute oral toxicity, genotoxicity, antigenotoxicity, and biochemical tests), compound A could be a promising candidate for further clinical testing.

Synthesis, in vitro anticancer activity, and pharmacokinetic profiling of the new tetrahydropyrimidines: Part I

Different vanillin-based aldehydes were used to synthesize novel tetrahydropyrimidines (THPMs) via conventional Biginelli reaction. The THPMs were tested against human normal cells (MRC-5) and cancer cell lines (HeLa, K562, and MDA-MB-231). With IC50 values of 10.65, 10.70, and 12.76 µM, compounds 4g, 4h, and 4i exerted the strongest cytotoxic effects against K562 cells. The best activity was achieved for 4g on MDA-MB-231 cells (IC50 = 9.20 ± 0.14 µM). The effects of compounds 4g, 4h, and 4i on the cell-cycle phase distribution of K562 cells were analyzed. Principal component analysis was carried out for the chemometrics analysis to comprehend the relationship between the anticancer activity of the THPMs, pharmacokinetic properties, and partition coefficients, as well as the relationship between the chromatographic behavior and retention parameters. The highest retention rates are found for molecules 4g, 4h, and 4i, which have the longest carbon chains, indicating that the length of the alkyl chain positively affects the molecule's anticancer activity but only if the number of carbon atoms is not higher than seven. Additionally, molecular docking analysis was performed to determine the preferred binding modes of the investigated ligands (4g, 4h, and 4i) with a DNA dodecamer and bovine serum albumin.

Kinesin-5/Cut7 C-terminal tail phosphorylation is essential for microtubule sliding force and bipolar mitotic spindle assembly

Kinesin-5 motors play an essential role during mitotic spindle assembly in many organisms1,2,3,4,5,6,7,8,9,10,11: they crosslink antiparallel spindle microtubules, step toward plus ends, and slide the microtubules apart.12,13,14,15,16,17 This activity separates the spindle poles and chromosomes. Kinesin-5s are not only plus-end-directed but can walk or be carried toward MT minus ends,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34 where they show enhanced localization.3,5,7,27,29,32 The kinesin-5 C-terminal tail interacts with and regulates the motor, affecting structure, motility, and sliding force of purified kinesin-535,36,37 along with motility and spindle assembly in cells.27,38,39 The tail contains phosphorylation sites, particularly in the conserved BimC box.6,7,40,41,42,43,44 Nine mitotic tail phosphorylation sites were identified in the kinesin-5 motor of the fission yeast Schizosaccharomyces pombe,45,46,47,48 suggesting that multi-site phosphorylation may regulate kinesin-5s. Here, we show that mutating all nine sites to either alanine or glutamate causes temperature-sensitive lethality due to a failure of bipolar spindle assembly. We characterize kinesin-5 localization and sliding force in the spindle based on Cut7-dependent microtubule minus-end protrusions in cells lacking kinesin-14 motors.39,49,50,51,52 Imaging and computational modeling show that Cut7p simultaneously moves toward the minus ends of protrusion MTs and the plus ends of spindle midzone MTs. Phosphorylation mutants show dramatic decreases in protrusions and sliding force. Comparison to a model of force to create protrusions suggests that tail truncation and phosphorylation mutants decrease Cut7p sliding force similarly to tail-truncated human Eg5.36 Our results show that C-terminal tail phosphorylation is required for kinesin-5/Cut7 sliding force and bipolar spindle assembly in fission yeast.

Design and synthesis of ferrocenyl 1,4-dihydropyridines and their evaluation as kinesin-5 inhibitors

Kinesin-5 inhibitors offer cancer cell-targeted approach, thus securing reduced systemic toxicity compared to other antimitotic agents. By modifying the 1,4-dihydropyridine-based kinesin-5 inhibitor CPUYL064 with a ferrocenyl moiety (Fc), we designed and prepared a series of organometallic hybrids that show high antiproliferative activity, with the best compounds exhibiting up to 19-fold increased activity. This enhanced activity can be attributed to the presence of the ferrocenyl moiety.

Regulation of p53 by the mitotic surveillance/stopwatch pathway: implications in neurodevelopment and cancer

The transcription factor p53 (encoded by TP53) plays diverse roles in human development and disease. While best known for its role in tumor suppression, p53 signaling also influences mammalian development by triggering cell fate decisions in response to a wide variety of stresses. After over 4 decades of study, a new pathway that triggers p53 activation in response to mitotic delays was recently identified. Termed the mitotic surveillance or mitotic stopwatch pathway, the USP28 and 53BP1 proteins activate p53 in response to delayed mitotic progression to control cell fate and promote genomic stability. In this Minireview, I discuss its identification, potential roles in neurodevelopmental disorders and cancer, as well as explore outstanding questions about its function, regulation and potential use as a biomarker for anti-mitotic therapies.

Spatiotemporal control of structure and dynamics in a polar active fluid

We apply optimal control theory to a model of a polar active fluid (the Toner-Tu model), with the objective of driving the system into particular emergent dynamical behaviors or programming switching between states on demand. We use the effective self-propulsion speed as the control parameter (i.e. the means of external actuation). We identify control protocols that achieve outcomes such as relocating asters to targeted positions, forcing propagating solitary waves to reorient to a particular direction, and switching between stationary asters and propagating fronts. We analyze the solutions to identify generic principles for controlling polar active fluids. Our findings have implications for achieving spatiotemporal control of active polar systems in experiments, particularly in vitro cytoskeletal systems. Additionally, this research paves the way for leveraging optimal control methods to engineer the structure and dynamics of active fluids more broadly.

One-pot synthesis of tetrahydropyrimidinecarboxamides enabling in vitro anticancer activity: a combinative study with clinically relevant brain-penetrant drugs

In this study, we describe a one-pot three-component synthesis of bioactive tetrahydopyrimidinecarboxamide derivatives employing lanthanum triflate as a catalyst. Out of the synthesized compounds, 4f had the most potent anti-cancer activity and impeded cell cycle progression effectively. Anti-cancer bioactivity was observed in 4f against liver, breast, and lung cancers as well as primary patient-derived glioblastoma cell lines. Compound 4f effectively inhibited the 3D neurosphere formation in primary patient-derived glioma stem cells. Specifically, 4f exhibited synergistic cytotoxicity with the EGFR inhibitor that is the clinical epidermal growth factor receptor inhibitor osimertinib. 4f does not exhibit anti-kinase activity and is cytostatic in nature, and further work is needed to understand the true molecular target of 4f and its derivatives. Through our current work, we establish a promising tetrahydopyrimidinecarboxamide-based lead compound with anti-cancer activity, which may exhibit potent anti-cancer activity in combination with specific clinically relevant small molecule kinase inhibitors.

Innovating cancer drug discovery with refined phenotypic screens

Before molecular pathways in cancer were known to a depth that could predict targets, drug development relied on phenotypic screening, where the effectiveness of candidate chemicals is judged from functional readouts without considering the mechanisms of action. The unraveling of tumor-specific pathways has brought targets for molecularly driven drug discovery, but precedents in the field have shown that awareness of pathways does not necessarily predict therapeutic efficacy, and many cancers still lack druggable targets. Phenotypic screening therefore retains a niche in drug development where a targeted approach is not informative. We analyze the unique advantages of phenotypic screens, and how technological advances have improved their discovery power. Notable advances include the use of larger biological panels and refined protocols that address the disease-relevance and increase data content with imaging and omic approaches.

Synthesis of novel fatty acid 3,4-dihydropyrimidin-2-(1H)-one and antitumoral activity against breast and gastric cancer cells

Monastrol is the best-known small compound from the dihydropyrimidinones/thiones (DHPMs) heterocycle family, a cell-permeable molecule recognized as an inhibitor of mitotic kinesin Eg5, that is over-expressed in tumor cells and is a very promising target for the development of new drugs for cancer. The lipophilic properties of the DHPMs have been demonstrated to be of pivotal importance in the design of new molecules. This work describes the synthesis and antitumoral activity of novel C5-substituted fatty-DHPMs against breast and gastric cancer cell lines. The compounds were synthesized via Biginelli multicomponent reaction from oleyl β-ketoester in good yields (40-72%) using a simple approach catalyzed by nontoxic and free-metal sulfamic acid. Among the compounds tested, the compound 10c, derived from 3-hydroxybenzaldehyde and urea, exhibited 77% cellular viability to normal cells (C2C12) and was selected to be evaluated against tumoral breast (MCF-7) and gastric (AGS) cell lines. The results obtained afforded an IC50 of breast cancer cells of 2.3 μM, qualifying the molecule as the most potent, and making it a promising compound for future experiments in vivo.

Measuring and modeling the dynamics of mitotic error correction

Error correction is central to many biological systems and is critical for protein function and cell health. During mitosis, error correction is required for the faithful inheritance of genetic material. When functioning properly, the mitotic spindle segregates an equal number of chromosomes to daughter cells with high fidelity. Over the course of spindle assembly, many initially erroneous attachments between kinetochores and microtubules are fixed through the process of error correction. Despite the importance of chromosome segregation errors in cancer and other diseases, there is a lack of methods to characterize the dynamics of error correction and how it can go wrong. Here, we present an experimental method and analysis framework to quantify chromosome segregation error correction in human tissue culture cells with live cell confocal imaging, timed premature anaphase, and automated counting of kinetochores after cell division. We find that errors decrease exponentially over time during spindle assembly. A coarse-grained model, in which errors are corrected in a chromosome-autonomous manner at a constant rate, can quantitatively explain both the measured error correction dynamics and the distribution of anaphase onset times. We further validated our model using perturbations that destabilized microtubules and changed the initial configuration of chromosomal attachments. Taken together, this work provides a quantitative framework for understanding the dynamics of mitotic error correction.

Binding patterns of inhibitors to different pockets of kinesin Eg5

The kinesin-5 family member, Eg5, plays very important role in the mitosis. As a mitotic protein, Eg5 is the target of various mitotic inhibitors. There are two targeting pockets in the motor domain of Eg5, which locates in the α2/L5/α3 region and the α4/α6 region respectively. We investigated the interactions between the different inhibitors and the two binding pockets of Eg5 by using all-atom molecular dynamics method. Combined the conformational analysis with the free-energy calculation, the binding patterns of inhibitors to the two binding pockets are shown. The α2/L5/α3 pocket can be divided into 4 regions. The structures and binding conformations of inhibitors in region 1 and 2 are highly conserved. The shape of α4/α6 pocket is alterable. The space of this pocket in ADP-binding state of Eg5 is larger than that in ADP·Pi-binding state due to the limitation of a hydrogen bond formed in the ADP·Pi-binding state. The results of this investigation provide the structural basis of the inhibitor-Eg5 interaction and offer a reference for the Eg5-targeted drug design.

Antiparallel microtubule bundling supports KIF15-driven mitotic spindle assembly

The spindle is a bipolar microtubule-based machine that is crucial for accurate chromosome segregation. Spindle bipolarity is generated by Eg5 (a kinesin-5), a conserved motor that drives spindle assembly by localizing to and sliding apart antiparallel microtubules. In the presence of Eg5 inhibitors (K5Is), KIF15 (a kinesin-12) can promote spindle assembly, resulting in K5I-resistant cells (KIRCs). However, KIF15 is a less potent motor than Eg5, suggesting that other factors may contribute to spindle formation in KIRCs. Protein Regulator of Cytokinesis 1 (PRC1) preferentially bundles antiparallel microtubules, and we previously showed that PRC1 promotes KIF15-microtubule binding, leading us to hypothesize that PRC1 may enhance KIF15 activity in KIRCs. Here, we demonstrate that: 1) loss of PRC1 in KIRCs decreases spindle bipolarity, 2) overexpression of PRC1 increases spindle formation efficiency in KIRCs, 3) overexpression of PRC1 protects K5I naïve cells against the K5I S-trityl-L-cysteine (STLC), and 4) PRC1 overexpression promotes the establishment of K5I resistance. These effects are not fully reproduced by a TPX2, a microtubule bundler with no known preference for microtubule orientation. These results suggest a model wherein PRC1-mediated bundling of microtubules creates a more favorable microtubule architecture for KIF15-driven mitotic spindle assembly in the context of Eg5 inhibition.

Monastrol suppresses invasion and metastasis in human colorectal cancer cells by targeting fascin independent of kinesin-Eg5 pathway

Rearrangement of the actin cytoskeleton is a prerequisite for carcinoma cells to develop cellular protrusions, which are required for migration, invasion, and metastasis. Fascin is a key protein involved in actin bundling and is expressed in aggressive and invasive carcinomas. Additionally, fascin appears to be involved in tubulin-binding and microtubule rearrangement. Pharmacophoric-based in silico screening was performed to identify compounds with better fascin inhibitory properties than migrastatin, a gold-standard fascin inhibitor. We hypothesized that monastrol displays anti-migratory and anti-invasive properties via fascin blocking in colorectal cancer cell lines. Biophysical (thermofluor and ligand titration followed by fluorescence spectroscopy), biochemical (NMR), and cellular assays (MTT, invasion of human tissue), as well as animal model studies (zebrafish invasion) were performed to characterize the inhibitory effect of monastrol on fascin activity. In silico analysis revealed that monastrol is a potential fascin-binding compound. Biophysical and biochemical assays demonstrated that monastrol binds to fascin and interferes with its actin-bundling activity. Cell culture studies, including a 3D human myoma disc model, showed that monastrol inhibited fascin-driven cytoplasmic protrusions as well as invasion. In silico, confocal microscopy, and immunoprecipitation assays demonstrated that monastrol disrupted fascin-tubulin interactions. These anti-invasive effects were confirmed in vivo. In silico confocal microscopy and immunoprecipitation assays were carried out to test whether monastrol disrupted the fascin-tubulin interaction. This study reports, for the first time, the in vitro and in vivo anti-invasive properties of monastrol in colorectal tumor cells. The number and types of interactions suggest potential binding of monastrol across actin and tubulin sites on fascin, which could be valuable for the development of antitumor therapies.

Coumarin as an Elite Scaffold in Anti-Breast Cancer Drug Development: Design Strategies, Mechanistic Insights, and Structure-Activity Relationships

Breast cancer is the most common cancer among women. Currently, it poses a significant threat to the healthcare system due to the emerging resistance and toxicity of available drug candidates in clinical practice, thus generating an urgent need for the development of new potent and safer anti-breast cancer drug candidates. Coumarin (chromone-2-one) is an elite ring system widely distributed among natural products and possesses a broad range of pharmacological properties. The unique distribution and pharmacological efficacy of coumarins attract natural product hunters, resulting in the identification of numerous natural coumarins from different natural sources in the last three decades, especially those with anti-breast cancer properties. Inspired by this, numerous synthetic derivatives based on coumarins have been developed by medicinal chemists all around the globe, showing promising anti-breast cancer efficacy. This review is primarily focused on the development of coumarin-inspired anti-breast cancer agents in the last three decades, especially highlighting design strategies, mechanistic insights, and their structure-activity relationship. Natural coumarins having anti-breast cancer efficacy are also briefly highlighted. This review will act as a guideline for researchers and medicinal chemists in designing optimum coumarin-based potent and safer anti-breast cancer agents.

Photosynthesis of C-1-Deuterated Aldehydes via Chlorine Radical-Mediated Selective Deuteration of the Formyl C-H Bond

C-1-deuterated aldehydes are essential building blocks in the synthesis of deuterated chemicals and pharmaceuticals. This has led chemists to devise mild methodologies for their efficient production. Ideally, hydrogen-deuterium exchange (HDE) is the most effective approach. However, the traditional HDE for creating C-1-deuterated aldehydes often requires a complex system involving multiple catalysts and/or ligands. In this study, we present a mild photocatalytic HDE of the formyl C-H bond with D2O. This process is facilitated by chlorine radicals that are generated in situ from low-cost FeCl3. This strategy demonstrated a broad reaction scope and high functional group tolerance, affording good yields and ≤99% D incorporation. To bridge the gap between research and industrial applications, we designed a new flow photoreactor equipped with a high-intensity light-emitting diode bucket, enabling the synthesis of C-1-deuterated aldehydes on a scale of 85 g. Finally, we successfully produced several important deuterated aldehydes that are integral to the synthesis of deuterated pharmaceuticals.

Revisiting Biginelli-like reactions: solvent effects, mechanisms, biological applications and correction of several literature reports

This study critically reevaluates reported Biginelli-like reactions using a Kamlet-Abboud-Taft-based solvent effect model. Surprisingly, structural misassignments were discovered in certain multicomponent reactions, leading to the identification of pseudo three-component derivatives instead of the expected MCR adducts. Attempts to replicate literature conditions failed, prompting reconsideration of the described MCRs and proposed mechanisms. Electrospray ionization (tandem) mass spectrometry, NMR, melting points, elemental analyses and single-crystal X-ray analysis exposed inaccuracies in reported MCRs and allowed for the proposition of a complete catalytic cycle. Biological investigations using both pure and "contaminated" derivatives revealed distinctive features in assessed bioassays. A new cellular action mechanism was unveiled for a one obtained pseudo three-component adduct, suggesting similarity with the known dihydropyrimidinone Monastrol as Eg5 inhibitors, disrupting mitosis by forming monoastral mitotic spindles. Docking studies and RMSD analyses supported this hypothesis. The findings described herein underscore the necessity for a critical reexamination and potential corrections of structural assignments in several reports. This work emphasizes the significance of rigorous characterization and critical evaluation in synthetic chemistry, urging a careful reassessment of reported synthesis and biological activities associated with these compounds.

Human kinesin-5 KIF11 drives the helical motion of anti-parallel and parallel microtubules around each other

During mitosis, motor proteins and microtubule-associated protein organize the spindle apparatus by cross-linking and sliding microtubules. Kinesin-5 plays a vital role in spindle formation and maintenance, potentially inducing twist in the spindle fibers. The off-axis power stroke of kinesin-5 could generate this twist, but its implications in microtubule organization remain unclear. Here, we investigate 3D microtubule-microtubule sliding mediated by the human kinesin-5, KIF11, and found that the motor caused right-handed helical motion of anti-parallel microtubules around each other. The sidestepping ratio increased with reduced ATP concentration, indicating that forward and sideways stepping of the motor are not strictly coupled. Further, the microtubule-microtubule distance (motor extension) during sliding decreased with increasing sliding velocity. Intriguingly, parallel microtubules cross-linked by KIF11 orbited without forward motion, with nearly full motor extension. Altering the length of the neck linker increased the forward velocity and pitch of microtubules in anti-parallel overlaps. Taken together, we suggest that helical motion and orbiting of microtubules, driven by KIF11, contributes to flexible and context-dependent filament organization, as well as torque regulation within the mitotic spindle.

Identifying and characterising promising small molecule inhibitors of kinesin spindle protein using ligand-based virtual screening, molecular docking, molecular dynamics and MM‑GBSA calculations

The kinesin spindle protein (Eg5) is a mitotic protein that plays an essential role in the formation of the bipolar spindles during the mitotic phase. Eg5 protein controls the segregation of the chromosomes in mitosis which renders it a vital target for cancer treatment. In this study our approach to identifying novel scaffold for Eg5 inhibitors is based on targeting the novel allosteric pocket (α4/α6/L11). Extensive computational techniques were applied using ligand-based virtual screening and molecular docking by two approaches, MOE and AutoDock, to screen a library of commercial compounds. We identified compound 8-(3-(1H-imidazol-1-ylpropylamino)-3-methyl-7-((naphthalen-3-yl)methyl)-1H-purine-2, 6 (3H,7H)-dione (compound 5) as a novel scaffold for Eg5 inhibitors. This compound inhibited cancer cell Eg5 ATPase at 2.37 ± 0.15 µM. The molecular dynamics simulations revealed that the identified compound formed stable interactions in the allosteric pocket (α4/α6/L11) of the receptor, indicating its potential as a novel Eg5 inhibitor.

Spastin regulates anaphase chromosome separation distance and microtubule-containing nuclear tunnels

Nuclear envelope reassembly during the final stages of each mitosis depends on disassembling spindle microtubules without disrupting chromosome separation. This process involves the transient recruitment of the ESCRT-III complex and spastin, a microtubule-severing AAA (ATPases associated with diverse cellular activities) mechanoenzyme, to late-anaphase chromosomes. However, dissecting mechanisms underlying these rapid processes, which can be completed within minutes, has been difficult. Here, we combine fast-acting chemical inhibitors with live-cell imaging and find that spindle microtubules, along with spastin activity, regulate the number and lifetimes of spastin foci at anaphase chromosomes. Unexpectedly, spastin inhibition impedes chromosome separation, but does not alter the anaphase localization dynamics of CHMP4B, an ESCRT-III protein, or increase γ-H2AX foci, a DNA damage marker. We show spastin inhibition increases the frequency of lamin-lined nuclear microtunnels that can include microtubules penetrating the nucleus. Our findings suggest failure to sever spindle microtubules impedes chromosome separation, yet reforming nuclear envelopes can topologically accommodate persistent microtubules ensuring nuclear DNA is not damaged or exposed to cytoplasm.

A green bio-organic catalyst (taurine) promoted one-pot synthesis of (R/S)-2-thioxo-3,4-dihydropyrimidine(TDHPM)-5-carboxanilides: chiral investigations using circular dichroism and validation by computational approaches

Owing to the massive importance of dihydropyrimidine (DHPMs) scaffolds in the pharmaceutical industry and other areas, we developed an effective and sustainable one-pot reaction protocol for the synthesis of (R/S)-2-thioxo-DHPM-5-carboxanilides via the Biginelli-type cyclo-condensation reaction of aryl aldehydes, thiourea and various acetoacetanilide derivatives in ethanol at 100 °C. In this protocol, taurine was used as a green and reusable bio-organic catalyst. Twenty-three novel derivatives of (R/S)-TDHPM-5-carboxanilides and their structures were confirmed by various spectroscopy techniques. The aforementioned compounds were synthesized via the formation of one asymmetric centre, one new C-C bond, and two new C-N bonds in the final product. All the newly synthesized compounds were obtained in their racemic form with up to 99% yield. In addition, the separation of the racemic mixture of all the newly synthesized compounds was carried out by chiral HPLC (Prep LC), which provided up to 99.99% purity. The absolute configuration of all the enantiomerically pure isomers was determined using a circular dichroism study and validated by a computational approach. With up to 99% yield of 4d, this one-pot synthetic approach can also be useful for large-scale industrial production. One of the separated isomers (4R)-(+)-4S developed as a single crystal, and it was found that this crystal structure was orthorhombic.

Cytotoxic monastrol derivatives as adjective inhibitors of drug-resistant Eg5: a molecular dynamics perspective

The mitotic kinesin Eg5 is a motor protein involved in the formation of bipolar spindle and cell division. Eg5 is overexpressed in various cancer cells and Eg5 targeting agents are promising candidates for cancer therapy. Subsequent to the discovery of monastrol as a small-molecule Eg5 modulator, numerous inhibitors/modulators have been reported from which a few entered clinical trials. Mutagenic investigations specified declined sensitivity of Eg5 allosteric site to monastrol due to the occurrence of drug-resistant mutations in some cell cultures. Accordingly, identification of tight binders to the mutant Eg5 allosteric site is an invaluable strategy to devise more efficient Eg5 modulators. We have previously synthesized a few dihydropyrimidinethione (DHPMT)-based 5-carboxamide monastrol derivatives (1-5) with higher cytotoxicities against AGS (IC50 9.90-98.48 µM) and MCF-7 (IC50 15.20-149.13 µM) cancer cell lines than monastrol. Within a current study, a structural insight was offered into the binding mechanism of intended derivatives inside the mutant Eg5 loop5/α2/α3 allosteric pocket. Molecular docking of the DHPMT R and S-enantiomers unraveled top-scored Eg5 complexes. Molecular dynamics (MD) simulations were carried out on 5 superior complexes as (R)-2/D130V-Eg5, (R)-4/D130V-Eg5, (R)-5/D130V-Eg5, (R)-5/L214I-Eg5, (R)-5/R119L-Eg5, and the control groups monastrol/D130V-Eg5, monastrol/L214I-Eg5, monastrol/R119L-Eg5. Free energy calculations were conducted through conformational sampling of MD-driven binding trajectories. Our results provided structural details on probable interaction mechanism of the cytotoxic DHPMTs that are difficult to address experimentally. The outputs of the current study propose new monastrol derivatives as probable resistance-overwhelming Eg5 modulators.

Loss-of-function of kinesin-5 KIF11 causes microcephaly, chorioretinopathy, and developmental disorders through chromosome instability and cell cycle arrest

Kinesin motors play a fundamental role in development by controlling intracellular transport, spindle assembly, and microtubule organization. In humans, patients carrying mutations in KIF11 suffer from an autosomal dominant inheritable disease called microcephaly with or without chorioretinopathy, lymphoedema, or mental retardation (MCLMR). While mitotic functions of KIF11 proteins have been well documented in centrosome separation and spindle assembly, cellular mechanisms underlying KIF11 dysfunction and MCLMR remain unclear. In this study, we generate KIF11-inhibition chick and zebrafish models and find that KIF11 inhibition results in microcephaly, chorioretinopathy, and severe developmental defects in vivo. Notably, loss-of-function of KIF11 causes the formation of monopolar spindle and chromosome misalignment, which finally contribute to cell cycle arrest, chromosome instability, and cell death. Our results demonstrate that KIF11 is crucial for spindle assembly, chromosome alignment, and cell cycle progression of progenitor stem cells, indicating a potential link between polyploidy and MCLMR. Our data have revealed that KIF11 inhibition cause microcephaly, chorioretinopathy, and development disorders through the formation of monopolar spindle, polyploid, and cell cycle arrest.

Sliding of antiparallel microtubules drives bipolarization of monoastral spindles

Time-lapse imaging with liquid crystal polarized light (LC-PolScope) and fluorescent speckle microscopy (FSM) enabled this study of spindle microtubules in monoastral spindles that were produced in crane-fly spermatocytes through flattening-induced centrosome displacement. Monoastral spindles are found in several other contexts: after laser ablation of one of a cell's two centrosomes (in the work of Khodjakov et al.), in Drosophila "urchin" mutants (in the works of Heck et al. and of Wilson et al.), in Sciara males (in the works of Fuge and of Metz), and in RNAi variants of Drosophila S2 cells (in the work of Goshima et al.). In all cases, just one pole has a centrosome (the astral pole); the other lacks a centrosome (the anastral pole). Thus, the question: How is the anastral half-spindle, lacking a centrosome, constructed? We learned that monoastral spindles are assembled in two phases: Phase I assembles the astral half-spindle composed of centrosomal microtubules, and Phase II assembles microtubules of the anastral half through extension of new microtubule polymerization outward from the spindle's equatorial mid-zone. That process uses plus ends of existing centrosomal microtubules as guiding templates to assemble anastral microtubules of opposite polarity. Anastral microtubules slide outward with their minus ends leading, thereby establishing proper bipolarity just like in normal biastral spindles that have two centrosomes.

C(sp2)-H selenylation of substituted benzo[4,5]imidazo[2,1-b]thiazoles using phenyliodine(iii)bis(trifluoroacetate) as a mediator

Herein, an expeditious metal-free regioselective C-H selenylation of substituted benzo[4,5]imidazo[2,1-b]thiazole derivatives was devised to synthesize structurally orchestrated selenoethers with good to excellent yields. This PIFA [bis(trifluoroacetoxy)iodobenzene]-mediated protocol operates under mild conditions and offers broad functional group tolerance. In-depth mechanistic investigation supports the involvement of radical pathways. Furthermore, the synthetic utility of this methodology is portrayed through gram-scale synthesis.

Dihydropyrimidine derivatives as MDM2 inhibitors

One of the chief pathways to regulate p53 levels is MDM2 protein, which negatively controls p53 by direct inhibition. Many cancers overproduce MDM2 protein to interrupt p53 functions. Therefore, impeding MDM2's binding to p53 can reactivate p53 in tumor cells may suggest an effective approach for tumor therapy. Here, some Monastrol derivatives were designed in silico as MDM2 inhibitors, and their initial cytotoxicity was evaluated in vitro on MFC-7 and MDA-MB-231 cells. A small library of Monastrol derivatives was created, and virtual screening (VS) was performed on them. The first-ranked compound, which was extracted from VS, and the other six compounds 5a-5f were selected to carry out the single-docking and docking with explicit waters. The compound with the best average results was then subjected to molecular dynamic (MD) simulation. Compounds 5a-5f were chemically synthesized and evaluated in vitro for their initial cytotoxicity on MFC-7 and MDA-MB-231 cells by MTT assay. The best compound was compound 5d with ΔGave  = -10.35 kcal/mol. MD simulation revealed a median potency in comparison with Nutlin-3a. The MTT assay confirmed the docking and MD experiments. 5d has an IC50 of 60.09 μM on MCF-7 cells. We attempted to use Monastrol scaffold as a potent inhibitor of MDM2 rather than an Eg5 inhibitor using in silico modification. The results obtained from the in silico and in vitro evaluations were noteworthy and warranted much more effort in the future.

High-throughput, microscopy-based screening and quantification of genetic elements

Synthetic biology relies on the screening and quantification of genetic components to assemble sophisticated gene circuits with specific functions. Microscopy is a powerful tool for characterizing complex cellular phenotypes with increasing spatial and temporal resolution to library screening of genetic elements. Microscopy-based assays are powerful tools for characterizing cellular phenotypes with spatial and temporal resolution and can be applied to large-scale samples for library screening of genetic elements. However, strategies for high-throughput microscopy experiments remain limited. Here, we present a high-throughput, microscopy-based platform that can simultaneously complete the preparation of an 8 × 12-well agarose pad plate, allowing for the screening of 96 independent strains or experimental conditions in a single experiment. Using this platform, we screened a library of natural intrinsic promoters from Pseudomonas aeruginosa and identified a small subset of robust promoters that drives stable levels of gene expression under varying growth conditions. Additionally, the platform allowed for single-cell measurement of genetic elements over time, enabling the identification of complex and dynamic phenotypes to map genotype in high throughput. We expected that the platform could be employed to accelerate the identification and characterization of genetic elements in various biological systems, as well as to understand the relationship between cellular phenotypes and internal states, including genotypes and gene expression programs.

Antibody drug conjugates beyond cytotoxic payloads

For many years, antibody drug conjugates (ADC) have teased with the promise of targeted payload delivery to diseased cells, embracing the targeting of the antibody to which a cytotoxic payload is conjugated. During the past decade this promise has started to be realised with the approval of more than a dozen ADCs for the treatment of various cancers. Of these ADCs, brentuximab vedotin really laid the foundations of a template for a successful ADC with lysosomal payload release from a cleavable dipeptide linker, measured DAR by conjugation to the Cys-Cys interchain bonds of the antibody and a cytotoxic payload. Using this ADC design model oncology has now expanded their repertoire of payloads to include non-cytotoxic compounds. These new payload classes have their origins in prior medicinal chemistry programmes aiming to design selective oral small molecule drugs. While this may not have been achieved, the resulting compounds provide excellent starting points for ADC programmes with some compounds amenable to immediate linker attachment while for others extensive SAR and structural information offer invaluable design insights. Many of these new oncology payload classes are of interest to other therapeutic areas facilitating rapid access to drug-linkers for exploration as non-oncology ADCs. Other therapeutic areas have also pursued unique payload classes with glucocorticoid receptor modulators (GRM) being the most clinically advanced in immunology. Here, ADC payloads come full circle, as oncology is now investigating GRM payloads for the treatment of cancer. This chapter aims to cover all these new ADC approaches while describing the medicinal chemistry origins of the new non-cytotoxic payloads.

Distinct regions of the kinesin-5 C-terminal tail are essential for mitotic spindle midzone localization and sliding force

Kinesin-5 motor proteins play essential roles during mitosis in most organisms. Their tetrameric structure and plus-end-directed motility allow them to bind to and move along antiparallel microtubules, thereby pushing spindle poles apart to assemble a bipolar spindle. Recent work has shown that the C-terminal tail is particularly important to kinesin-5 function: The tail affects motor domain structure, ATP hydrolysis, motility, clustering, and sliding force measured for purified motors, as well as motility, clustering, and spindle assembly in cells. Because previous work has focused on presence or absence of the entire tail, the functionally important regions of the tail remain to be identified. We have therefore characterized a series of kinesin-5/Cut7 tail truncation alleles in fission yeast. Partial truncation causes mitotic defects and temperature-sensitive growth, while further truncation that removes the conserved BimC motif is lethal. We compared the sliding force generated by cut7 mutants using a kinesin-14 mutant background in which some microtubules detach from the spindle poles and are pushed into the nuclear envelope. These Cut7-driven protrusions decreased as more of the tail was truncated, and the most severe truncations produced no observable protrusions. Our observations suggest that the C-terminal tail of Cut7p contributes to both sliding force and midzone localization. In the context of sequential tail truncation, the BimC motif and adjacent C-terminal amino acids are particularly important for sliding force. In addition, moderate tail truncation increases midzone localization, but further truncation of residues N-terminal to the BimC motif decreases midzone localization.

RAB11A and RAB11B control mitotic spindle function in intestinal epithelial progenitor cells

RAB11 small GTPases and associated recycling endosome have been localized to mitotic spindles and implicated in regulating mitosis. However, the physiological significance of such regulation has not been observed in mammalian tissues. We have used newly engineered mouse models to investigate intestinal epithelial renewal in the absence of single or double isoforms of RAB11 family members: Rab11a and Rab11b. Comparing with single knockouts, mice with compound ablation demonstrate a defective cell cycle entry and robust mitotic arrest followed by apoptosis, leading to a total penetrance of lethality within 3 days of gene ablation. Upon Rab11 deletion ex vivo, enteroids show abnormal mitotic spindle formation and cell death. Untargeted proteomic profiling of Rab11a and Rab11b immunoprecipitates has uncovered a shared interactome containing mitotic spindle microtubule regulators. Disrupting Rab11 alters kinesin motor KIF11 function and impairs bipolar spindle formation and cell division. These data demonstrate that RAB11A and RAB11B redundantly control mitotic spindle function and intestinal progenitor cell division, a mechanism that may be utilized to govern the homeostasis and renewal of other mammalian tissues.

Design, Synthesis, and Evaluation of Biological Activity of Ferrocene-Ispinesib Hybrids: Impact of a Ferrocenyl Group on the Antiproliferative and Kinesin Spindle Protein Inhibitory Activity

With the aim to combine more than one biologically-active component in a single molecule, derivatives of ispinesib and its (S) analogue were prepared that featured ferrocenyl moieties or bulky organic substituents. Inspired by the strong kinesin spindle protein (KSP) inhibitory activity of ispinesib, the compounds were investigated for their antiproliferative activity. Among these compounds, several derivatives demonstrated significantly higher antiproliferative activity than ispinesib with nanomolar IC50 values against cell lines. Further evaluation indicated that the antiproliferative activity is not directly correlated with their KSP inhibitory activity while docking suggested that several of the derivatives may bind in a manner similar to ispinesib. In order to investigate the mode of action further, cell cycle analysis and reactive oxygen species formation were investigated. The improved antiproliferative activity of the most active compounds may be assigned to synergic effects of various factors such as KSP inhibitory activity due to the ispinesib core and ability to generate ROS and induce mitotic arrest.