New MKLP-2 inhibitors in the paprotrain series: Design, synthesis and biological evaluations

Advancing Cancer Therapy: The Role of KIF20A as a Target for Inhibitor Development and Immunotherapy

The analysis begins with a detailed examination of the gene expression and protein structure of KIF20A, highlighting its interaction with critical cellular components that influence key processes such as Golgi membrane transport and mitotic spindle assembly. The primary focus is on the development of specific KIF20A inhibitors, detailing their roles and the challenges encountered in enhancing their efficacy, such as achieving specificity, overcoming tumor resistance, and optimizing delivery systems. Additionally, it delves into the prognostic value of KIF20A across multiple cancer types, emphasizing its role as a novel tumor-associated antigen, which lays the groundwork for the development of targeted peptide vaccines. The therapeutic efficacy of these vaccines as demonstrated in recent clinical trials is discussed. Future directions are proposed, including the integration of precision medicine strategies to personalize treatments and the use of combination therapies to improve outcomes. By concentrating on the significant potential of KIF20A as both a direct target for inhibitors and an antigen in cancer vaccines, this review sets a foundation for future research aimed at harnessing KIF20A for effective cancer treatment.

Maternal genetic variants in kinesin motor domains prematurely increase egg aneuploidy

The female reproductive lifespan depends on egg quality, particularly euploidy. Mistakes in meiosis leading to egg aneuploidy are common, but the genetic landscape causing this is not well understood due to limited phenotypic data. We identify genetic determinants of reproductive aging via egg aneuploidy using a biobank of maternal exomes linked with maternal age and embryonic aneuploidy data. We found 404 genes with variants enriched in individuals with high egg aneuploidy rates and implicate kinesin protein family genes in aneuploidy risk. Experimental perturbations showed that motor domain variants in these genes increase aneuploidy in mouse oocytes. A knock-in mouse model validated that a specific variant in kinesin KIF18A accelerates reproductive aging and diminishes fertility. These findings suggest potential non-invasive biomarkers for egg quality, aiding personalized fertility medicine.

One sentence summary

The study identifies novel genetic determinants of reproductive aging linked to egg aneuploidy by analyzing maternal exomes and demonstrates that variants in kinesin genes, specifically KIF18A , contribute to increased aneuploidy and accelerated reproductive aging, offering potential for personalized fertility medicine.

Green Halogenation of Indoles with Oxone-Halide

Oxidative functionalization of indoles is one of the most widely used approaches to exploit the synthetic utility of indoles. In continuation of our research interest in the green oxidation of indoles, we further explore the oxidation of indoles with oxone-halide and discover that the protecting group on the nitrogen of indoles plays a decisive role in controlling the pathways of indole oxidation with oxone-halide. An electron-withdrawing group on the nitrogen of indoles (N-EWG) enables C2 halogenation with stoichiometric halide, while C3 halogenation could be selectively achieved by using stoichiometric halide without dependence on the electronic property of the protecting group on the indole nitrogen. Different from our previous results obtained by using catalytic halide, these findings lead to the development of an environmentally friendly, efficient, and mild protocol for access to 2- or 3-haloindoles (chloro and bromo). As compared to the previous synthetic methods for 2-/3-haloindoles, our method exploits the in situ-generated reactive halogenating species from oxone-halide for halogenation of indoles and thus eliminates the use of stoichiometric halogenating agents and the production of toxic and hazardous organic byproducts derived from oxidants.

Indole-Acrylonitrile Derivatives as Potential Antitumor and Antimicrobial Agents-Synthesis, In Vitro and In Silico Studies

A series of 2-(1H-indol-2-yl)-3-acrylonitrile derivatives, 2a-x, 3, 4a-b, 5a-d, 6a-b, and 7, were synthesized as potential antitumor and antimicrobial agents. The structures of the prepared compounds were evaluated based on elemental analysis, IR, ¹H- and ¹³NMR, as well as MS spectra. X-ray crystal analysis of the representative 2-(1H-indol-2-yl)-3-acrylonitrile 2l showed that the acrylonitrile double bond was Z-configured. All compounds were screened at the National Cancer Institute (USA) for their activities against a panel of approximately 60 human tumor cell lines and the relationship between structure and in vitro antitumor activity is discussed. Compounds of interest 2l and 5a-d showed significant growth inhibition potency against various tumor cell lines with the mean midpoint GI₅₀ values of all tests in the range of 0.38-7.91 μM. The prominent compound with remarkable activity (GI₅₀ = 0.0244-5.06 μM) and high potency (TGI = 0.0866-0.938 μM) against some cell lines of leukemia (HL-60(TB)), non-small cell lung cancer (NCI-H522), colon cancer (COLO 205), CNS cancer (SF-539, SNB-75), ovarian cancer ((OVCAR-3), renal cancer (A498, RXF 393), and breast cancer (MDA-MB-468) was 3-[4-(dimethylamino)phenyl]-2-(1-methyl-1H-indol-2-yl)acrylonitrile (5c). Moreover, the selected 2-(1H-indol-2-yl)-3-acrylonitriles 2a-c and 2e-x were evaluated for their antibacterial and antifungal activities against Gram-positive and Gram-negative pathogens as well as Candida albicans. Among them, 2-(1H-indol-2-yl)-3-(1H-pyrrol-2-yl)acrylonitrile (2x) showed the most potent antimicrobial activity and therefore it can be considered as a lead structure for further development of antimicrobial agents. Finally, molecular docking studies as well as drug-likeness and ADME profile prediction were carried out.

An overview of cdc2-like kinase 1 (Clk1) inhibitors and their therapeutic indications

Over the past decade, Clk1 has been identified as a promising target for the treatment of various diseases, in which deregulated alternative splicing plays a role. First small molecules targeting Clk1 are in clinical trials for the treatment of solid cancer, where variants of oncogenic proteins derived from alternative splicing promote tumor progression. Since many infectious pathogens hi-jack the host cell's splicing machinery to ensure efficient replication, further indications in this area are under investigation, such as Influenza A, HIV-1 virus, and Trypanosoma infections, and more will likely be discovered in the future. In addition, Clk1 was found to contribute to the progression of Alzheimer's disease through causing an imbalance of tau splicing products. Interestingly, homozygous Clk1 knockout mice showed a rather mild phenotype, opposed to what might be expected in view of the profound role of Clk1 in alternative splicing. A major drawback of most Clk1 inhibitors is their insufficient selectivity; in particular, Dyrk kinases and haspin were frequently identified as off-targets, besides the other Clk isoforms. Only few inhibitors were shown to be selective over Dyrk1A and haspin, whereas no Clk1 inhibitor so far achieved selectivity over the Clk4 isoform. In this review, we carefully compiled all Clk1 inhibitors from the scientific literature and summarized their structure-activity relationships (SAR). In addition, we critically discuss the available selectivity data and describe the inhibitor's efficacy in cellular models, if reported. Thus, we provide a comprehensive overview on the current state of Clk1 drug discovery and highlight the most promising chemotypes.

The Impact of Nitrile-Specifier Proteins on Indolic Carbinol and Nitrile Formation in Homogenates of Arabidopsis thaliana

Glucosinolates, specialized metabolites of the Brassicales including Brassica crops and Arabidopsis thaliana, have attracted considerable interest as chemical defenses and health-promoting compounds. Their biological activities are mostly due to breakdown products formed upon mixing with co-occurring myrosinases and specifier proteins, which can result in multiple products with differing properties, even from a single glucosinolate. Whereas product profiles of aliphatic glucosinolates have frequently been reported, indole glucosinolate breakdown may result in complex mixtures, the analysis of which challenging. The aim of this study was to assess the breakdown of indole glucosinolates in A. thaliana root and rosette homogenates and to test the impact of nitrile-specifier proteins (NSPs) on product profiles. To develop a GC-MS-method for quantification of carbinols and nitriles derived from three prominent indole glucosinolates, we synthesized standards, established derivatization conditions, determined relative response factors and evaluated applicability of the method to plant homogenates. We show that carbinols are more dominant among the detected products in rosette than in root homogenates of wild-type and NSP1- or NSP3-deficient mutants. NSP1 is solely responsible for nitrile formation in rosette homogenates and is the major NSP for indolic nitrile formation in root homogenates, with no contribution from NSP3. These results will contribute to the understanding of the roles of NSPs in plants.

Inhibition of KIF20A suppresses the replication of influenza A virus by inhibiting viral entry

The influenza A virus (IAV) has caused several pandemics, and therefore there are many ongoing efforts to identify novel antiviral therapeutic strategies including vaccines and antiviral drugs. However, influenza viruses continuously undergo antigenic drift and shift, resulting in the emergence of mutated viruses. In turn, this decreases the efficiency of existing vaccines and antiviral drugs to control IAV infection. Therefore, this study sought to identify alternative therapeutic strategies targeting host cell factors rather than viruses to avoid infection by mutated viruses. Particularly, we investigated the role of KIF20A that is one of kinesin superfamily proteins in the replication of IAV. The KIF20A increased viral protein levels in IAV-infected cells by regulating the initial entry stage during viral infection. Furthermore, the KIF20A inhibitor significantly suppressed viral replication, which protected mice from morbidity and mortality. Therefore, our findings demonstrated that KIF20A is highly involved in the viral replication process and viral propagation both in vitro and in vivo, and could thus be used as a target for the development of novel antiviral drugs.

MKLP2 functions in early mitosis to ensure proper chromosome congression

Mitotic kinesin-like protein 2 (MKLP2) is a motor protein with a well-established function in promoting cytokinesis. However, our results with siRNAs targeting MKLP2 and small molecule inhibitors of MKLP2 (MKLP2i) suggested a function earlier in mitosis, prior to anaphase. In this study we provide direct evidence that MKLP2 facilitates chromosome congression in prometaphase. We employed live imaging to observe HeLa cells with fluorescently tagged histones treated with MKLP2i and discovered a pronounced chromosome congression defect. We show that MKLP2 facilitates error correction as inhibited cells had a significant increase in unstable, syntelic kinetochore-microtubule attachments. We find that the aberrant attachments are accompanied by elevated Aurora Kinase (A/B) activity and phosphorylation of the downstream target, pHEC1 (Ser 55). Lastly, we show that MKLP2 inhibition results in aneuploidy, confirming that MKLP2 safeguards cells against chromosomal instability.

The kinesin KIF20A promotes progression to castration-resistant prostate cancer through autocrine activation of the androgen receptor

Prostate cancer that recurs following androgen-deprivation therapy is termed castration-resistant, which is incurable and is marked by reactivation of androgen receptor (AR) signaling. KIF20A, a kinesin with unique structural features, is overexpressed in human castration-resistant prostate cancer (CRPC) compared to androgen-dependent PC and benign tissue. KIF20A has well-described roles in mitotic processes, but it has a less characterized function in vesicle fission and trafficking within Golgi-driven secretory pathways. Stable expression of KIF20A in androgen-dependent PC cells promoted progression to CRPC through the activation of AR signaling in vitro and in vivo. KIF20A expression resulted in the secretion of autocrine factors in the conditioned media that activated AR and caused castration-resistant proliferation of naïve androgen-dependent cells. Pharmacologic disruption of vesicle biogenesis blocked KIF20A-driven castration-resistant proliferation of androgen-dependent PC. KIF20A depletion or treatment with the KIF20A-specific inhibitor, paprotrain, reduced CRPC. These data are the first to establish KIF20A as a driver of CRPC progression through AR activation and as a promising therapeutic target against CRPC.

Contribution of Knoevenagel Condensation Products towards Development of Anticancer Agents: An Updated Review

Knoevenagel condensation is an entrenched, prevailing, prominent arsenal following greener principles in the generation of α, β-unsaturated ketones/carboxylic acids by involving carbonyl functionalities and active methylenes. This reaction has proved to be a major driving force in many multicomponent reactions indicating the prolific utility towards the development of biologically fascinating molecules. This eminent reaction was acclimatised on different pharmacophoric aldehydes (benzimidazole, β-carboline, phenanthrene, indole, imidazothiadiazole, pyrazole etc.) and active methylenes (oxindole, barbituric acid, Meldrum's acid, thiazolidinedione etc.) to generate the library of chemical compounds. Their potential was also explicit to understand the significance of functionalities involved, which thereby evoke further developments in drug discovery. Furthermore, most of these reaction products exhibited remarkable anticancer activity in nanomolar to micromolar ranges by targeting different cancer targets like DNA, microtubules, Topo-I/II, and kinases (PIM, PARP, NMP, p300/CBP) etc. This review underscores the efficiency of the Knoevenagel condensation explored in the past six-year to generate molecules of pharmacological interest, predominantly towards cancer. The present review also provides the aspects of structure-activity relationships, mode of action and docking study with possible interaction with the target protein.

Design, synthesis, and pharmacological profiling of cannabinoid 1 receptor allosteric modulators: Preclinical efficacy of C2-group GAT211 congeners for reducing intraocular pressure

Allosteric modulators of cannabinoid 1 receptor (CB1R) show translational promise over orthosteric ligands due to their potential to elicit therapeutic benefit without cannabimimetic side effects. The prototypic 2-phenylindole CB1R allosteric modulator, GAT211 (1), demonstrates preclinical efficacy in various disease models. The limited systematic structure-activity relationship (SAR) data at the C2 position of the indole ring within GAT211 invites the opportunity for further modifications to improve GAT211's pharmacological profile while serving to amplify and variegate this library of therapeutically attractive agents. These considerations prompted this focused SAR study in which we substituted the GAT211 C2-phenyl ring with heteroaromatic substituents. The synthesized GAT211 analogs were then evaluated in vitro as CB1R allosteric modulators in cAMP and β-arrestin2 assays with CP55,940 as the orthosteric ligand. Furan and thiophene rings (15c-f and 15m) were the best-tolerated substituents at the C2 position of GAT211 for engagement with human CB1R (hCB1R). The SAR around the novel ligands reported allowed direct experimental characterization of the interaction profile of that pharmacophore with its binding domain in functional, human CB1R, thus offering guidance for accessing subsequent-generation hCB1R allosteric modulators as potential therapeutics. The most potent analog, 15d, markedly promoted orthosteric ligand binding to hCB1R. Pharmacological profiling in the GTPγS and mouse vas deferens assays demonstrated that 15d behaves as a CB1R agonist-positive allosteric modulator (ago-PAM), as confirmed electrophysiologically in autoptic neurons. In vivo, 15d was efficacious as a topical agent that significantly reduced intraocular pressure (IOP) in the ocular normotensive murine model of glaucoma. Since elevated IOP is a decisive risk factor for glaucoma and attendant vision loss, our data support the proposition that the 2-phenylindole class of CB1R ago-PAMs has therapeutic potential for glaucoma and other diseases where potentiation of CB1R signaling may be therapeutic.

Inhibition of KIF20A by BKS0349 reduces endometriotic lesions in a xenograft mouse model

Several studies have suggested a possible etiological association between ovarian endometriosis and ovarian cancer. Evidence has shown that KIF20A overexpression might confer a malignant phenotype to ovarian tumors by promoting proliferation and inhibiting apoptosis. However, no data about the role of KIF20A in endometriosis have been described. In this study, the human endometrium (n = 4) was transfected by mCherry adenovirus and intraperitoneally implanted in mice. Subsequently, mice were divided in three groups (n = 8/group) that were treated with Vehicle, BKS0349 (KIF20A-antagonist) or cabergoline (dopamine receptor agonist) for 21 days. mCherry-labeled endometriotic lesions were monitored over time using the IVIS Imaging System. Mice were sacrificed 72 h after the last administration; proliferation was evaluated by immunohistochemistry and apoptosis by TUNEL. CCND1 gene expression (G1 phase-related gene) was measured by qRT-PCR. A significant reduction in mCherry-fluorescent signal was observed in the BKS0349 group after treatment ended (D24) compared with D0 (P-value = 0.0313). Moreover, the mCherry signal on D24 showed a significant decrease in the BKS0349 group compared with controls (P-value = 0.0303), along with significant size reduction of endometriotic lesions observed in the BKS0349 group compared with control on D24 (P-value = 0.0006). Functional studies showed a significant reduction in proliferating cells in the BKS0349-treated group compared with controls (P-value = 0.0082). In addition, CCND1 expression was decreased in the BKS0349 group compared with control (P-value = 0.049) at D24 and a significant increase in apoptotic cells among endometriotic lesions in BKS0349-treated mice was observed compared with control (P-value = 0.0317). Based on these findings, we concluded that BKS0349 induces apoptosis and inhibits cell proliferation, reducing endometriotic lesion size and suggesting KIF20A inhibition by BKS0349 as a novel therapeutic treatment for endometriosis.

Characterization of KIF20A as a prognostic biomarker and therapeutic target for different subtypes of breast cancer

The aim of the present study was to identify novel prognostic biomarkers and therapeutic targets for breast cancer; thus, genes that are frequently overexpressed in several types of breast cancer were screened. Kinesin family member 20A (KIF20A) was identified as a candidate molecule during this process. Immunohistochemical staining performed using tissue microarrays from 257 samples of different breast cancer subtypes revealed that KIF20A was expressed in 195 (75.9%) of these samples, whereas it was seldom expressed in normal breast tissue. KIF20A protein was expressed in all types of breast cancer observed. However, it was more frequently expressed in human epidermal growth factor receptor 2 (HER2)‑positive and triple‑negative breast cancer than in the luminal type. Moreover, KIF20A expression was significantly associated with the poor prognosis of patients with breast cancer. A multivariate analysis indicated that KIF20A expression was an independent prognostic factor for patients with breast cancer. The suppression of endogenous KIF20A expression using small interfering ribonucleic acids or via treatment with paprotrain, a selective inhibitor of KIF20A, significantly inhibited breast cancer cell growth through cell cycle arrest at the G2/M phase and subsequent mitotic cell death. These results suggest that KIF20A is a candidate prognostic biomarker and therapeutic target for different types of breast cancer.

FOXM1: a potential therapeutic target in human solid cancers

Introduction: FOXM1 is one of the most frequently overexpressed proteins in human solid cancers. Here, we discuss novel direct targets of FOXM1 as well as new pathways involving FOXM1, through which this protein exerts its oncogenic activity.Areas covered: We give a detailed review of FOXM1 transcriptional targets involved in 16 different types of human cancer as published in the literature in the last 5 years. We also discuss a novel positive feedback loop between FOXM1 and AKT - both well-established master regulators of cancer.Expert opinion: Despite the discovery of several FOXM1 inhibitors over the years (by our team and others), their therapeutic use is limited by their adverse off-target effects.Newly-discovered proteins regulated by FOXM1 present a promising alternative approach to target its pro-cancer activity. In addition, targeting regulating proteins that take part in the positive feedback loop between FOXM1/AKT has the double advantage of suppressing both, and can lead to developing novel anti-cancer drugs.

KIF20A, highly expressed in immature hematopoietic cells, supports the growth of HL60 cell line

A microtubule-associated motor protein, kinesin-like family member 20A (KIF20A; also called MKlp2) is required for cytokinesis and contributes to intracellular vesicular trafficking. KIF20A plays a critical role in the development of several cancers, but its role in blood cells and hematological malignancies have not been studied. In the present study, we focused on the role of KIF20A in hematopoietic cells and possible involvement in myeloid neoplasms. We found that human leukemia cell lines and normal bone marrow CD34-positive cells stimulated by growth factors, but not mature peripheral blood cells, exhibit high KIF20A expression. We further found that HL60 cells, which originally express a large amount of KIF20A, showed decreased KIF20A expression in parallel with both neutrophil-like and macrophage-like differentiation-induction. KIF20A-knockdown using a lentivirus shRNA transfection system led to partial cell cycle arrest at the G2/M phase and frequent appearance of multinucleated cells. Treatment with a KIF20A-selective inhibitor, paprotrain enhanced the multinuclearity of KIF20A-knockdown cell clones and suppressed growth. The present study contributes to our understanding of the role of KIF20A in blood cells and leukemia cells in particular.

The divergent mitotic kinesin MKLP2 exhibits atypical structure and mechanochemistry

MKLP2, a kinesin-6, has critical roles during the metaphase-anaphase transition and cytokinesis. Its motor domain contains conserved nucleotide binding motifs, but is divergent in sequence (~35% identity) and size (~40% larger) compared to other kinesins. Using cryo-electron microscopy and biophysical assays, we have undertaken a mechanochemical dissection of the microtubule-bound MKLP2 motor domain during its ATPase cycle, and show that many facets of its mechanism are distinct from other kinesins. While the MKLP2 neck-linker is directed towards the microtubule plus-end in an ATP-like state, it does not fully dock along the motor domain. Furthermore, the footprint of the MKLP2 motor domain on the MT surface is altered compared to motile kinesins, and enhanced by kinesin-6-specific sequences. The conformation of the highly extended loop6 insertion characteristic of kinesin-6s is nucleotide-independent and does not contact the MT surface. Our results emphasize the role of family-specific insertions in modulating kinesin motor function.

Cells constantly replicate to provide new cells for growing tissues, and to replace ageing or defective cells around the body. Each new cell needs a copy of the genetic material, and a cellular structure called the mitotic spindle makes sure that this material is shared correctly when a cell divides in two. The spindle is built from protein filaments called microtubules, and the protein filaments grow and shrink as the mitotic spindle carries out its role. Many of these changes in the spindle are driven by proteins called molecular motors, which break down energy-rich molecules of ATP to power them as they walk along the filaments.

Kinesins, for example, are molecular motors that can move along microtubules and there are over 40 different kinesins encoded in the human genome. More than half of the human kinesins are involved in cell division including one called MKLP2. Little is known about MKLP2 but some earlier findings had suggested that it would behave very differently compared to other kinesins.

Understanding how a kinesin motor works requires studying it in complex with its microtubule tracks. Atherton, Yu et al. have now used a technique called cryo-electron microscopy – which is uniquely suited to looking at large and complicated samples in three dimensions – to observe how the motor in MKLP2 changes shape as it works. This revealed that, while MKLP2 works in a fundamentally similar way to other kinesins, many aspects of its molecular mechanism are highly unusual. These include how it binds to the microtubule, how it interacts with ATP and how it generates force.

These findings show that there is much greater diversity in the molecular mechanisms of the kinesins involved in cell division than was previously thought. Several anticancer drugs target kinesins to stop cells dividing and so this diversity may make it easier to target only certain kinesins with drugs, which in turn would have fewer side effects. First, though, it will be important to find out how the unusual mechanism of MKLP2 coordinates and influences other components of the spindle to reveal a fuller picture of what happens when cells replicate.

Depsidones from Lichens as Natural Product Inhibitors of M-Phase Phosphoprotein 1, a Human Kinesin Required for Cytokinesis

M-Phase Phosphoprotein 1 (MPP1), a microtubule plus end directed kinesin, is required for the completion of cytokinesis. Previous studies have shown that MPP1 is upregulated in various types of bladder cancer. This article describes inhibitor screening leading to the identification of a new class of natural product inhibitors of MPP1. Two compounds with structural similarity, norlobaridone (1) and physodic acid (2), were found to inhibit MPP1. Physodic acid is not competitive with ATP, indicating the presence of an allosteric inhibitor-binding pocket. Initial drug-like property screening indicates that physodic acid is more soluble than norlobaridone and has more favorable lipophilicity. However, both suffer from high clearance in human microsomal stability assays mediated by the lability of the lactone ring as well as hydroxylation of the alkyl chains as shown by metabolite identification studies. In cell-based assays physodic acid is a weak inhibitor with EC50 values of about 30 μM in a range of tumor cell lines. The two depsidones identified and characterized here could be used for future improvement of their activity against MPP1 and will be useful chemical probes for studying this unique molecular motor in more depth.