Impaired angiogenesis and tumor development by inhibition of the mitotic kinesin Eg5

CpG methylation changes associated with hyperglycemia in type 1 diabetes occur at angiogenic glomerular and retinal gene loci

Chronic hyperglycemia is a major risk factor for glomerular or retinal microangiopathy and cardiovascular complications of type 1 diabetes (T1D). At the interface of genetics and environment, dynamic epigenetic changes associated with hyperglycemia may unravel some of the mechanisms contributing to these T1D complications. In this study, blood samples were collected from 112 young patients at T1D diagnosis and 3 years later in average. Whole genome-wide bisulfite sequencing was used to measure blood DNA methylation changes of about 28 million CpGs at single base resolution over this time. Chronic hyperglycemia was estimated every 3-4 months by HbA1c measurement. Linear regressions with adjustment to age, sex, treatment duration, blood proportions and batch effects were employed to characterize the relationships between the dynamic changes of DNA methylation and average HbA1c levels. We identified that longitudinal DNA methylation changes at 815 CpGs (with suggestive p-value threshold of 1e-4) were associated with average HbA1c. Most of them (> 98%) were located outside of the promoter regions and were enriched in CpG island shores and multiple immune cell type specific accessible chromatin regions. Among the 36 more strongly associated loci (p-value < 5e-6), 16 were harbouring genes or non-coding sequences involved in angiogenesis regulation, glomerular and retinal vascularization or development, or coronary disease. Our findings support the identification of new genomic sites where CpG methylation associated with hyperglycemia may contribute to long-term complications of T1D, shedding light on potential mechanisms for further exploration.

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.

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.

Targeting the EGFR and Spindle Assembly Checkpoint Pathways in Oral Cancer: A Plausible Alliance to Enhance Cell Death

Background/Objectives: Head and neck cancer (HNC) is among the most common cancer types globally, with its incidence expected to increase significantly in the coming years. Oral squamous cell carcinoma (OSCC), the predominant subtype, exhibits significant heterogeneity and resistance to treatment. Current therapies, including surgery, radiation, and chemotherapy, often result in poor outcomes for advanced stages. Cetuximab, an EGFR inhibitor, is widely used but faces limitations. This study explores the combined inhibition of EGFR and mitotic proteins to enhance treatment efficacy. Methods: We analyzed the effects of co-treating OSCC cells with small molecules targeting MPS-1 (BAY1217389), Aurora-B (Barasertib), or KSP (Ispinesib), alongside Cetuximab. The rationale is based on targeting EGFR-mediated survival pathways and the mitotic checkpoint, addressing multiple cell cycle phases and reducing resistance. Results: Our findings indicate that inhibiting MPS-1, Aurora-B, or KSP enhances Cetuximab's therapeutic potential, promoting increased cancer cell death. Additionally, we examined EGFR, MPS-1, Aurora-B, and KSP expression in OSCC patient samples, revealing their clinicopathologic significance. Conclusions: This combinatorial approach suggests a promising strategy to improve treatment outcomes in OSCC.

Eg5 and Diseases: From the Well-Known Role in Cancer to the Less-Known Activity in Noncancerous Pathological Conditions

Eg5 is a protein encoded by KIF11 gene and is primarily involved in correct mitotic cell division. It is also involved in nonmitotic processes such as polypeptide synthesis, protein transport, and angiogenesis. The scientific literature sheds light on the ubiquitous functions of KIF11 and its involvement in the onset and progression of different pathologies. This review focuses attention on two main points: (1) the correlation between Eg5 and cancer and (2) the involvement of Eg5 in noncancerous conditions. Regarding the first point, several tumors revealed an overexpression of this kinesin, thus pushing to look for new Eg5 inhibitors for clinical practice. In addition, the evaluation of Eg5 expression represents a crucial step, as its overexpression could predict a poor prognosis for cancer patients. Referring to the second point, in specific pathological conditions, the reduced activity of Eg5 can be one of the causes of pathological onset. This is the case of Alzheimer's disease (AD), in which Aβ and Tau work as Eg5 inhibitors, or in acquired immune deficiency syndrome (AIDS), in which Tat-mediated Eg5 determines the loss of CD4+ T-lymphocytes. Reduced Eg5 activity, due to mutations of KIF11 gene, is also responsible for pathological conditions such as microcephaly with or without chorioretinopathy, lymphedema, or intellectual disability (MCLRI) and familial exudative vitreous retinopathy (FEVR). In conclusion, this review highlights the double impact that overexpression or loss of function of Eg5 could have in the onset and progression of different pathological situations. This emphasizes, on one hand, a possible role of Eg5 as a potential biomarker and new target in cancer and, on the other hand, the promotion of Eg5 expression/activity as a new therapeutic strategy in different noncancerous diseases.

Coupling Kinesin Spindle Protein and Aurora B Inhibition with Apoptosis Induction Enhances Oral Cancer Cell Killing

Many proteins regulating mitosis have emerged as targets for cancer therapy, including the kinesin spindle protein (KSP) and Aurora kinase B (AurB). KSP is crucial for proper spindle pole separation during mitosis, while AurB plays roles in chromosome segregation and cytokinesis. Agents targeting KSP and AurB selectively affect dividing cells and have shown significant activity in vitro. However, these drugs, despite advancing to clinical trials, often yield unsatisfactory outcomes as monotherapy, likely due to variable responses driven by cyclin B degradation and apoptosis signal accumulation networks. Accumulated data suggest that combining emerging antimitotics with various cytostatic drugs can enhance tumor-killing effects compared to monotherapy. Here, we investigated the impact of inhibiting anti-apoptotic signals with the BH3-mimetic Navitoclax in oral cancer cells treated with the selective KSP inhibitor, Ispinesib, or AurB inhibitor, Barasertib, aiming to potentiate cell death. The combination of BH3-mimetics with both KSP and AurB inhibitors synergistically induced substantial cell death, primarily through apoptosis. A mechanistic analysis underlying this synergistic activity, undertaken by live-cell imaging, is presented. Our data underscore the importance of combining BH3-mimetics with antimitotics in clinical trials to maximize their effectiveness.

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.

Phenotype-Based Genetic Analysis Reveals Missing Heritability of KIF11-Related Retinopathy: Clinical and Genetic Findings

The purpose of this study was to detect the missing heritability of patients with KIF11-related retinopathy and to describe their clinical and genetic characteristics. We enrolled 10 individuals from 7 unrelated families harboring a pathogenic monoallelic variant in KIF11. All subjects underwent ophthalmic assessment and extraocular phenotype evaluations, as well as comprehensive molecular genetic analyses using next-generation sequencing. Minigene assays were performed to observe the effects of one novel deep intron variant (DIV) and one novel synonymous variant on pre-mRNA splicing. We detected 6 novel different disease-causing variants of KIF11 in the seven pedigrees. Co-segregation analysis and ultra-deep sequencing results indicated that 5 variants arose de novo in 5 families (71%). Functional validation revealed that the synonymous variant leads to an exon skip, while the DIV causes a pseudoexon (PE) inclusion. The patients presented with high variations in their phenotype, and two families exhibited incomplete penetrance. Ocular manifestations and characteristic facial features were observed in all patients, as well as microcephaly in seven patients, intellectual disability in five patients, and lymphedema in one patient. The key retinal features for KIF11-related retinopathy were retinal folds, tractional retinal detachment, and chorioretinal dysplasia. All seven probands had more severe visual detects than other affected family members. Our findings widen the genetic spectrum of KIF11 variants. DIV explained rare unresolved cases with KIF11-related retinopathy. The patients displayed a variable phenotype expressivity and incomplete penetrance, indicating the importance of genetic analysis for patients with KIF11-related retinopathy.

High expression of KIF20A in bladder cancer as a potential prognostic target for poor survival of renal cell carcinoma

Urinary system tumors are malignant tumors, including renal cancer and bladder cancer. however, molecular target of them remains unclear. GSE14762 and GSE53757 were downloaded from GEO database to screen differentially expressed genes (DEGs). Weighted gene co-expression network analysis was performed. Gene Ontology (GO) and Kyoto encyclopedia of genes and genomes were used for enrichment analysis. Gene ontology and Kyoto encyclopedia of genes and genomes analyses were performed on whole genome, as formulated by gene set enrichment analysis. Survival analysis was also performed. Comparative toxicogenomics database was used to identify diseases most associated with hub genes. A total of 1517 DEGs were identified. DEGs were mainly enriched in cancer pathway, HIF-1 signaling pathway, organic acid metabolism, glyoxylate and dicarboxylate metabolism, and protein homodimerization activity. Ten hub genes (TPX2, ASPM, NUSAP1, RAD51AP1, CCNA2, TTK, PBK, MELK, DTL, kinesin family member 20A [KIF20A]) were obtained, which were up-regulated in tumor tissue. The expression of KIF20A was related with the overall survival of renal and bladder cancer. KIF20A was up-regulated in the tumor tissue, and might worsen the overall survival of bladder and kidney cancer. KIF20A could be a novel biomarker of bladder and kidney cancer.

Kinesin Eg5 Selective Inhibition by Newly Synthesized Molecules as an Alternative Approach to Counteract Breast Cancer Progression: An In Vitro Study

Breast cancer (BC) is one of the most diagnosed cancers in women. Recently, a promising target for BC treatment was found in kinesin Eg5, a mitotic motor protein that allows bipolar spindle formation and cell replication. Thus, the aim of this work was to evaluate the effects of novel thiadiazoline-based Eg5 inhibitors, analogs of K858, in an in vitro model of BC (MCF7 cell line). Compounds 2 and 41 were selected for their better profile as they reduce MCF7 viability at lower concentrations and with minimal effect on non-tumoral cells with respect to K858. Compounds 2 and 41 counteract MCF7 migration by negatively modulating the NF-kB/MMP-9 pathway. The expression of HIF-1α and VEGF appeared also reduced by 2 and 41 administration, thus preventing the recruitment of the molecular cascade involved in angiogenesis promotion. In addition, 2 provokes an increased caspase-3 activation thus triggering the MCF7 apoptotic event, while 41 and K858 seem to induce the necrosis axis, as disclosed by the increased expression of PARP. These results allow us to argue that 2 and 41 are able to simultaneously intervene on pivotal molecular signaling involved in breast cancer progression, leading to the assumption that Eg5 inhibition can represent a valid approach to counteract BC progression.

Cancer-Induced Metabolic Rewiring of Tumor Endothelial Cells

Simple Summary

Angiogenesis, the formation of new blood vessels from preexisting ones, is a complex and demanding biological process that plays an important role in physiological, as well as pathological conditions, including cancer. During tumor growth, the induction of angiogenesis allows tumor cells to grow, invade, and metastasize. Recent evidence supports endothelial cell metabolism as a critical regulator of angiogenesis. However, whether and how tumor endothelial cells rewire their metabolism in cancer remains elusive. In this review, we discussed the metabolic signatures of tumor endothelial cells and their symbiotic, competitive, and mechanical metabolic interactions with tumor cells. We also discussed the recent works that may provide a rationale for attractive metabolic targets and strategies for developing specific therapies against tumor angiogenesis.

Abstract

Cancer is a leading cause of death worldwide. If left untreated, tumors tend to grow and spread uncontrolled until the patient dies. To support this growth, cancer cells need large amounts of nutrients and growth factors that are supplied and distributed to the tumor tissue by the vascular system. The aberrant tumor vasculature shows deep morphological, molecular, and metabolic differences compared to the blood vessels belonging to the non-malignant tissues (also referred as normal). A better understanding of the metabolic mechanisms driving the differences between normal and tumor vasculature will allow the designing of new drugs with a higher specificity of action and fewer side effects to target tumors and improve a patient’s life expectancy. In this review, we aim to summarize the main features of tumor endothelial cells (TECs) and shed light on the critical metabolic pathways that characterize these cells. A better understanding of such mechanisms will help to design innovative therapeutic strategies in healthy and diseased angiogenesis.

The kinesin Eg5 inhibitor K858 exerts antiproliferative and proapoptotic effects and attenuates the invasive potential of head and neck squamous carcinoma cells

Our group recently demonstrated that K858, an inhibitor of motor kinesin Eg5, has important antiproliferative and apoptotic effects on breast cancer, prostatic cancer, melanoma and glioblastoma cells. Since high levels of kinesin Eg5 expression have been correlated with a poor prognosis in laryngeal carcinoma, we decided to test the anticancer activity of K858 toward this tumor, which belongs to the group of head and neck squamous cell carcinomas (HNSCCs). These cancers are characterized by low responsiveness to therapy. The effects of K858 on the proliferation and assembly of mitotic spindles of three human HNSCC cell lines were studied using cytotoxicity assays and immunofluorescence for tubulin. The effect of K858 on the cell cycle was analyzed by FACS. The expression levels of cyclin B1 and several markers of apoptosis and invasion were studied by Western blot. Finally, the negative regulation of the malignant phenotype by K858 was evaluated by an invasion assay. K858 inhibited cell replication by rendering cells incapable of developing normal bipolar mitotic spindles. At the same time, K858 blocked the cell cycle in the G2 phase and induced the accumulation of cytoplasmic cyclin B and, eventually, apoptosis. Additionally, K858 inhibited cell migration and attenuated the malignant phenotype. The data described confirm that kinesin Eg5 is an interesting target for new anticancer strategies and suggest that this compound may be a powerful tool for an alternative therapeutic approach to HNSCCs.

KIF11 as a potential cancer prognostic marker promotes tumorigenesis in children with Wilms tumor

Emerging evidence suggests that KIF11 could play a pivotal role in cancer cell proliferation; however, its biological functions and molecular mechanisms in Wilms tumor (WT) cells are largely unknown. The aim of this study was to evaluate the clinical significance and therapeutic potential of KIF11 proteins in WT. KIF11 expression in WT tissues and adjacent nontumor tissues was determined using qRT-PCR, Western blotting, immunohistochemistry (IHC) and bioinformatics. The function of KIF11 protein was determined by its correlation with tumor cell growth, angiogenesis, and apoptosis using IHC and lentiviral vector-mediated KIF11 depletion. KIF11 expression was upregulated in WT tissues and was associated with WT clinical outcomes. Tumor KIF11 expression was significantly associated with the Ki67 proliferation index. CCK-8, flow-cytometric analysis, and Western blotting revealed that KIF11 knockdown significantly inhibited WT cell growth. Functional studies have indicated that increased KIF11 expression is significantly correlated with vascular endothelial growth factor (VEGF) expression and intratumoral microvessel density. We further confirmed that downregulated expression of KIF11 promoted cell apoptosis and significantly increased Bcl-2 and Bax expression. Our findings demonstrate that KIF11 plays a role in promoting the development of human WT and can serve as a potential molecular marker for the treatment of WT.

Negative Modulation of the Angiogenic Cascade Induced by Allosteric Kinesin Eg5 Inhibitors in a Gastric Adenocarcinoma In Vitro Model

Eg5 is a kinesin essential in bipolar spindle formation, overexpressed in tumours, thus representing a new target in cancer therapy. We aimed at evaluating the anti-cancer activity of Eg5 thiadiazoline inhibitors 2 and 41 on gastric adenocarcinoma cells (AGS), focusing on the modulation of angiogenic signalling. Docking studies confirmed a similar interaction with Eg5 to that of the parent compound K858. Thiadiazolines were also tested in combination with Hesperidin (HSD). Cell cycle analysis reveals a reduction of G1 and S phase percentages when 41 is administered as well as HSD in combination with K858. Western blot reveals Eg5 inhibitors capability to reduce PI3K, p-AKT/Akt and p-Erk/Erk expressions; p-Akt/Akt ratio is even more decreased in HSD+2 sample than the p-Erk/Erk ratio in HSD+41 or K858. VEGF expression is reduced when HSD+2 and HSD+41 are administered with respect to compounds alone, after 72 h. ANGPT2 gene expression increases in cells treated with 41 and HSD+2 compared to K858. The wound-healing assay highlights a reduction in the cut in HSD+2 sample compared to 2 and HSD. Thus, Eg5 inhibitors appear to modulate angiogenic signalling by controlling VEGF activity even better if combined with HSD. Overall, Eg5 inhibitors can represent a promising starting point to develop innovative anti-cancer strategies.

Development and physiological functions of the lymphatic system: insights from human genetic studies of primary lymphedema

Primary lymphedema is a long-term (chronic) condition characterized by tissue lymph retention and swelling that can affect any part of the body, although it usually develops in the arms or legs. Due to the relevant contribution of the lymphatic system to human physiology, while this review mainly focuses on the clinical and physiological aspects related to the regulation of fluid homeostasis and edema, clinicians need to know that the impact of lymphatic dysfunction with a genetic origin can be wide ranging. Lymphatic dysfunction can affect immune function so leading to infection; it can influence cancer development and spread, and it can determine fat transport so impacting on nutrition and obesity. Genetic studies and the development of imaging techniques for the assessment of lymphatic function have enabled the recognition of primary lymphedema as a heterogenic condition in terms of genetic causes and disease mechanisms. In this review, the known biological functions of several genes crucial to the development and function of the lymphatic system are used as a basis for understanding normal lymphatic biology. The disease conditions originating from mutations in these genes are discussed together with a detailed clinical description of the phenotype and the up-to-date knowledge in terms of disease mechanisms acquired from in vitro and in vivo research models.

Exploratory comparisons between different anti-mitotics in clinically-used drug combination in triple negative breast cancer

Triple-negative breast cancer (TNBC) constitutes a very aggressive type of breast cancer with few options of cytotoxic chemotherapy available for them. A chemotherapy regimen comprising of doxorubicin hydrochloride and cyclophosphamide, followed by paclitaxel, known as AC-T, is approved for usage as an adjuvant treatment for this type of breast cancer. In this study we aimed to elucidate the role of KIF11 in TNBC progression throughout its inhibition by two synthetic small molecules containing the DHPM core (dihydropyrimidin-2(1H)-ones or -thiones), with the hypothesis that these inhibitors could be an interesting option of antimitotic drug used alone or as adjuvant therapy in association with AC. For this purpose, we evaluated the efficacy of DHPMs used as monotherapy or in combination with doxorubicin and cyclophosphamide, in Balbc-nude mice bearing breast cancer induced by MDA-MB-231, having AC-T as positive control. Our data provide extensive evidence to demonstrate that KIF11 inhibitors showed pronounced antitumor activity, acting in key points of tumorigenesis and cancer progression in in vivo xenograft model of triple negative breast cancer, like down-regulation of KIF11 and ALDH1-A1. Moreover, they didn’t show the classic peripheral neuropathy characterized by impaired mobility, as it is common with paclitaxel use. These results suggest that the use of a MAP inhibitor in breast cancer regimen treatment could be a promising strategy to keep antitumoral activity reducing the side effects.

Identification of a novel mutation in KIF11 with functional analysis in a cohort of 516 familial patients with exudative vitreoretinopathy

Purpose

To identify a novel mutation in KIF11 with clinical and functional analysis among 516 familial patients with exudative vitreoretinopathy (FEVR).

Methods

Next-generation sequencing was performed on 516 patients with FEVR between January 2015 and October 2017. Clinical data were collected from patient charts, including sex, age at presentation, visual acuity if available, axial length, stage, and systemic clinical findings. Protein and mRNA levels were detected with western blotting and real-time quantitative PCR, respectively. Mass spectrometry was used to analyze the interacting protein of KIF11.

Results

In total, 304 of 516 patients were identified with at least one mutation in FEVR causative genes. Mutations in KIF11 were identified in 14.47% of all carriers. The novel mutation p. H718L accounted for the greatest proportion (12/44; 27.30%) among all mutations in KIF11. Fundus presentations in these 12 individuals varied from the avascular zone of the peripheral retina to total retinal detachment. The p. H718L mutation can reduce the proliferation of human retinal endothelial cells (HRECs) compared to the wild type. The mRNA level of vascular endothelial growth factor-α, transforming growth factor-α, metalloproteinase-1, and angiopoietin-like 4 were depressed in the KIF11 (p. H718L) groups under hypoxia stimuli. Mass spectrometry results demonstrated that eukaryotic elongation factor 2 (EEF2) was an interacting protein of KIF11 and that the p. H718L mutation can attenuate the binding activity.

Conclusions

Patients with the most frequent KIF11 mutation p. H718L showed typical FEVR presentations in this cohort. The mutation in KIF11 likely plays a role in the proliferation of HRECs, and the p. H718L mutation can reduce the proliferation.

A mouse model for kinesin family member 11 (Kif11)-associated familial exudative vitreoretinopathy

During mitosis, Kif11, a kinesin motor protein, promotes bipolar spindle formation and chromosome movement, and during interphase, Kif11 mediates diverse trafficking processes in the cytoplasm. In humans, inactivating mutations in KIF11 are associated with (1) retinal hypovascularization with or without microcephaly and (2) multi-organ syndromes characterized by variable combinations of lymphedema, chorioretinal dysplasia, microcephaly and/or mental retardation. To explore the pathogenic basis of KIF11-associated retinal vascular disease, we generated a Kif11 conditional knockout (CKO) mouse and investigated the consequences of early postnatal inactivation of Kif11 in vascular endothelial cells (ECs). The principal finding is that postnatal EC-specific loss of Kif11 leads to severely stunted growth of the retinal vasculature, mildly stunted growth of the cerebellar vasculature and little or no effect on the vasculature elsewhere in the central nervous system (CNS). Thus, in mice, Kif11 function in early postnatal CNS ECs is most significant in the two CNS regions-the retina and cerebellum-that exhibit the most rapid rate of postnatal growth, which may sensitize ECs to impaired mitotic spindle function. Several lines of evidence indicate that these phenotypes are not caused by reduced beta-catenin signaling in ECs, despite the close resemblance of the Kif11 CKO phenotype to that caused by EC-specific reductions in beta-catenin signaling. Based on prior work, defective beta-catenin signaling had been the only known mechanism responsible for monogenic human disorders of retinal hypovascularization. The present study implies that retinal hypovascularization can arise from a second and mechanistically distinct cause.

The chorioallantoic membrane as a bio-barrier model for the evaluation of nanoscale drug delivery systems for tumour therapy

In 2010, the European Parliament and the European Union adopted a directive on the protection of animals used for scientific purposes. The directive aims to protect animals in scientific research, with the final goal of complete replacement of procedures on live animals for scientific and educational purposes as soon as it is scientifically viable. Furthermore, the directive announces the implementation of the 3Rs principle: "When choosing methods, the principles of replacement, reduction and refinement should be implemented through a strict hierarchy of the requirement to use alternative methods." The visibility, accessibility, and the rapid growth of the chorioallantoic membrane (CAM) offers a clear advantage for various manipulations and for the simulation of different Bio-Barriers according to the 3R principle. The extensive vascularisation on the CAM provides an excellent substrate for the cultivation of tumour cells or tumour xenografts which could be used for the therapeutic evaluation of nanoscale drug delivery systems. The tumour can be targeted either by topical application, intratumoural injection or i.v. injection. Different application sites and biological barriers can be examined within a single model.

Mechanisms by Which Kinesin-5 Motors Perform Their Multiple Intracellular Functions

Bipolar kinesin-5 motor proteins perform multiple intracellular functions, mainly during mitotic cell division. Their specialized structural characteristics enable these motors to perform their essential functions by crosslinking and sliding apart antiparallel microtubules (MTs). In this review, we discuss the specialized structural features of kinesin-5 motors, and the mechanisms by which these features relate to kinesin-5 functions and motile properties. In addition, we discuss the multiple roles of the kinesin-5 motors in dividing as well as in non-dividing cells, and examine their roles in pathogenetic conditions. We describe the recently discovered bidirectional motility in fungi kinesin-5 motors, and discuss its possible physiological relevance. Finally, we also focus on the multiple mechanisms of regulation of these unique motor proteins.

Retinal Features of Family Members With Familial Exudative Vitreoretinopathy Caused By Mutations in KIF11 Gene

Purpose

To determine the clinical characteristics of patients and family members with familial exudative vitreoretinopathy (FEVR) caused by mutations in the KIF11 gene.

Methods

Twenty-one patients from 10 FEVR families with mutations in the KIF11 gene were studied. The retinal and systemic features were examined. The genetic analyses performed included Sanger sequencing of the KIF11 gene, whole exome sequencing, as well as array comparative genomic hybridization (CGH) analysis and multiple ligation probe assay (MLPA).

Results

Sequence analysis revealed seven different KIF11 mutations. Array CGH with MLPA revealed two different exon deletions. All probands had advanced FEVR with retinal detachments (RDs) and microcephaly with or without developmental disabilities. Patients with bilateral RDs were more frequently associated with developmental disabilities (P = 0.023). Multimodal imaging of the family members revealed that six of nine patients without RDs (66%) had varying degrees of chorioretinopathy. The retinal folds in FEVR patients were associated with severe retinal avascularization. However, funduscopic changes in the peripheral retina were unremarkable in family members without RDs. A score representing the peripheral vascular anomalies determined from the fluorescein angiograms was lower than that of control eyes of patients with mutations of the Wnt signaling genes (P = 0.0029).

Conclusions

The probands with KIF11 mutations were associated with severe ocular and systemic pathologies, whereas affected family members showed highly variable clinical manifestations. Peripheral vascular anomalies can often be unremarkable in eyes without RDs.

Translational Relevance

These findings highlight more diverse mechanisms that underlie the pathological changes in patients with FEVR.

Genotype Phenotype Correlation and Variability in Microcephaly Associated With Chorioretinopathy or Familial Exudative Vitreoretinopathy

Purpose

The purpose of this study was to analyze the natural history and phenotypic overlap of patients with microcephaly and a chorioretinopathy or familial exudative vitreoretinopathy (FEVR) ocular phenotype caused by mutations in KIF11, TUBGCP4, or TUBGCP6.

Methods

Patients diagnosed with congenital microcephaly and chorioretinopathy or FEVR were included. Molecular investigations consisted of targeted genetic sequencing. Data from medical records, ophthalmologic examination and imaging, electroretinography, and visual fields were analyzed for systemic and ophthalmic features and evidence of posterior segment disease progression.

Results

Twelve patients from 9 families were included and had a median of 8 years of follow-up. Nine patients had KIF11 variants, two had heterozygous TUBGCP6 variants, and one had heterozygous variants in TUBGCP4. All patients had reduced visual function and multiple individuals and families showed features of both chorioretinopathy and FEVR. Progression of posterior segment disease was highly variable, with some degree of increased atrophy of the macula or peripheral retina or increased vitreoretinal traction observed in 9 of 12 patients.

Conclusions

Microcephaly due to mutations in KIF11, TUBGCP4, or TUBGCP6 can be associated with retinal disease on a spectrum from chorioretinal atrophy to FEVR-like posterior segment changes. Visually significant disease progression can occur and patients should be monitored closely by a team experienced in ophthalmic genetics.

Taxanes in cancer treatment: Activity, chemoresistance and its overcoming

Since 1984, when paclitaxel was approved by the FDA for the treatment of advanced ovarian carcinoma, taxanes have been widely used as microtubule-targeting antitumor agents. However, their historic classification as antimitotics does not describe all their functions. Indeed, taxanes act in a complex manner, altering multiple cellular oncogenic processes including mitosis, angiogenesis, apoptosis, inflammatory response, and ROS production. On the one hand, identification of the diverse effects of taxanes on oncogenic signaling pathways provides opportunities to apply these cytotoxic drugs in a more rational manner. On the other hand, this may facilitate the development of novel treatment modalities to surmount anticancer drug resistance. In the latter respect, chemoresistance remains a major impediment which limits the efficacy of antitumor chemotherapy. Taxanes have shown impact on key molecular mechanisms including disruption of mitotic spindle, mitosis slippage and inhibition of angiogenesis. Furthermore, there is an emerging contribution of cellular processes including autophagy, oxidative stress, epigenetic alterations and microRNAs deregulation to the acquisition of taxane resistance. Hence, these two lines of findings are currently promoting a more rational and efficacious taxane application as well as development of novel molecular strategies to enhance the efficacy of taxane-based cancer treatment while overcoming drug resistance. This review provides a general and comprehensive picture on the use of taxanes in cancer treatment. In particular, we describe the history of application of taxanes in anticancer therapeutics, the synthesis of the different drugs belonging to this class of cytotoxic compounds, their features and the differences between them. We further dissect the molecular mechanisms of action of taxanes and the molecular basis underlying the onset of taxane resistance. We further delineate the possible modalities to overcome chemoresistance to taxanes, such as increasing drug solubility, delivery and pharmacokinetics, overcoming microtubule alterations or mitotic slippage, inhibiting drug efflux pumps or drug metabolism, targeting redox metabolism, immune response, and other cellular functions.

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

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

Identification of KIF15 as a potential therapeutic target and prognostic factor for glioma

Glioma is the most commonly diagnosed primary intracranial malignant tumor with rapid growth, easy recurrence and thus poor prognosis. In the present study, the role of kinesin‑12 (KIF15) in glioma was revealed. Immunohistochemical staining and western blot analysis were used to detect the protein expression. An MTT assay was performed to evaluate cell proliferation. Flow cytometric analysis was utilized to assess cell apoptosis and the cell cycle. A mouse xenograft model was constructed for in vivo study. The results indicated that KIF15 was significantly upregulated in glioma tumor tissues and positively correlated with pathological staging, recurrence risk and poor prognosis. Silencing of KIF15 could inhibit cell proliferation and stemness of glioma cells, arrest cells in the G2 phase and induce cell apoptosis. The in vivo study verified the inhibitory effect of KIF15 knockdown on tumor growth. The mechanism study demonstrated the regulation of apoptosis‑ and cycle‑related proteins in the KIF15 KD‑induced inhibition of glioma. KIF15 was revealed to function as a tumor promoter in the development and progression of glioma. KIF15 also served as a prognostic indicator for glioma and may be a therapeutic target for glioma therapy.

Role of a Kinesin Motor in Cancer Cell Mechanics

Molecular motors play important roles in force generation, migration, and intracellular trafficking. Changes in specific motor activities are altered in numerous diseases. KIF20A, a motor protein of the kinesin-6 family, is overexpressed in bladder cancer, and KIF20A levels correlate negatively with clinical outcomes. We report here a new role for the KIF20A kinesin motor protein in intracellular mechanics. Using optical tweezers to probe intracellular mechanics and surface AFM to probe cortical mechanics, we first confirm that bladder urothelial cells soften with an increasing cancer grade. We then show that inhibiting KIF20A makes the intracellular environment softer for both high- and low-grade bladder cancer cells. Upon inhibition of KIF20A, cortical stiffness also decreases in lower grade cells, while it surprisingly increases in higher grade malignant cells. Changes in cortical stiffness correlate with the interaction of KIF20A with myosin IIA. Moreover, KIF20A inhibition negatively regulates bladder cancer cell motility irrespective of the underlying substrate stiffness. Our results reveal a central role for a microtubule motor in cell mechanics and migration in the context of bladder cancer.

Clinical and Molecular Characterization of Familial Exudative Vitreoretinopathy Associated With Microcephaly

PURPOSE

Familial exudative vitreoretinopathy (FEVR) is a rare finding in patients with genetic forms of microcephaly. This study documents the detailed phenotype and expands the range of genetic heterogeneity.

DESIGN

Retrospective case series.

METHODS

Twelve patients (10 families) with a diagnosis of FEVR and microcephaly were ascertained from pediatric genetic eye clinics and underwent full clinical assessment including retinal imaging. Molecular investigations included candidate gene Sanger sequencing, whole-exome sequencing (WES), and whole-genome sequencing (WGS).

RESULTS

All patients had reduced vision and nystagmus. Six were legally blind. Two probands carried bi-allelic LRP5 variants, both presenting with bilateral retinal folds. A novel homozygous splice variant, and 2 missense variants were identified. Subsequent bone density measurement identified osteoporosis in one proband. Four families had heterozygous KIF11 variants. Two probands had a retinal fold in one eye and chorioretinal atrophy in the other; the other 2 had bilateral retinal folds. Four heterozygous variants were found, including 2 large deletions not identified on Sanger sequencing or WES. Finally, a family of 2 children with learning difficulties, abnormal peripheral retinal vasculogenesis, and rod-cone dystrophy were investigated. They were found to have bi-allelic splicing variants in TUBGCP6. Three families remain unsolved following WES and WGS.

CONCLUSIONS

Molecular diagnosis has been achieved in 7 of 10 families investigated, including a previously unrecognized association with LRP5. WGS enabled molecular diagnosis in 3 families after prior negative Sanger sequencing of the causative gene. This has enabled patient-specific care with targeted investigations and accurate family counseling.

Redox-Responsive Nanoparticle-Mediated Systemic RNAi for Effective Cancer Therapy

Biodegradable polymeric nanoparticles (NPs) have demonstrated significant potential to improve the systemic delivery of RNA interference (RNAi) therapeutics, such as small interfering RNA (siRNA), for cancer therapy. However, the slow and inefficient siRNA release inside tumor cells generally observed for most biodegradable polymeric NPs may result in compromised gene silencing efficacy. Herein, a biodegradable and redox-responsive NP platform, composed of a solid poly(disulfide amide) (PDSA)/cationic lipid core and a lipid-poly(ethylene glycol) (lipid-PEG) shell for systemic siRNA delivery to tumor cells, is developed. This newly generated NP platform can efficiently encapsulate siRNA under extracellular environments and can respond to the highly concentrated glutathione (GSH) in the cytoplasm to induce fast intracellular siRNA release. By screening a library of PDSA polymers with different structures and chain lengths, the optimized NP platform shows the unique features of i) long blood circulation, ii) high tumor accumulation, iii) fast GSH-triggered intracellular siRNA release, and iv) exceptionally effective gene silencing. Together with the facile polymer synthesis technique and robust NP formulation enabling scale-up, this new redox-responsive NP platform may become an effective tool for RNAi-based cancer therapy.

Overexpression of kinesin family member 20A is associated with unfavorable clinical outcome and tumor progression in epithelial ovarian cancer

Background

KIF20A plays an indispensable role in cytokinesis regulation, which is important for tumor proliferation and growth. Recently, the oncogenic role of KIF20A has been well documented in several cancers. However, its clinical role in epithelial ovarian cancer (EOC) remains not reported yet. We investigated its expression and its role in promoting invasion and chemoresistance in EOC cells.

Patients and methods

KIF20A transcription and translation levels were investigated in normal ovarian epithelial cell, ovarian cancer cells, and 10 pairs of fresh EOC tissues and adjacent normal ovarian tissues by real-time quantitative polymerase chain reaction and Western blots. Moreover, KIF20A protein level was also examined by immunohistochemistry in 150 EOC tissues. The correlation between KIF20A expression and clinical variables was analyzed by statistical methods. We also used wound healing assay, transwell assay MTT, and Annexin V/PI to explore KIF20A functions.

Results

KIF20A expression was obviously elevated at both mRNA and protein levels in EOC cell lines and clinical cancer tissues compared with normal ovarian epithelial cell and adjacent normal ovarian tissues. KIF20A protein expression was highly correlated with International Federation of Gynecology and Obstetrics stage (P=0.008), lymph node metastasis (P=0.002), intraperitoneal metastasis (P<0.001), vital status at last follow-up (P<0.001), intraperitoneal recurrence (P=0.030), tumor recurrence (P=0.005), drug resistance (P=0.013), and ascites with tumor cells (P<0.001). KIF20A overexpression was closely related to poorer overall survival and disease progression-free survival. Furthermore, Cox regression analysis revealed that KIF20A can act as an independent hazard indicator for predicting clinical outcomes in EOC patients. Interestingly, KIF20A overexpression promoted invasion and metastasis of EOC cells and also confers resistance to cisplatin.

Conclusion

Our findings indicated that KIF20A overexpression predicts unfavorable clinical outcome, revealing that KIF20A holds a promising potential to serve as a useful prognostic biomarker for EOC patients.

Detection and quantification of a KIF11 mosaicism in a subject presenting familial exudative vitreoretinopathy with microcephaly

Familial exudative vitreoretinopathy (FEVR) is an inherited retinal disorder, which is primarily characterized by abnormal development of retinal vasculature. In this study, we reported a subject presenting the clinical features of FEVR as well as microcephaly. Screening of the KIF11 gene in this patient revealed a novel heterozygous protein-truncating variant (c.2717del, p.(L906*), NM_004523.3). Segregation analysis in the unaffected parents using Sanger sequencing suggested the variant to be present in a mosaic state in the unaffected mother. KIF11 exon 19 which harbors the variant was amplified from the proband and her father, as well as three different tissues of the mother, followed by amplicon-based deep sequencing. This analysis revealed that the variant is present in different tissues of the mother at various rates, i.e. in blood (16.9%), saliva (20.7%), or skin biopsy-derived fibroblast cells (6.6%). These data demonstrate the importance of deep sequencing in unaffected parents upon detection of a genetic defect in isolated cases to detect possible mosaicisms, enabling a  more reliable recurrence risk assessment and thereby improve genetic counseling.

A Novel Mutation of KIF11 in a Child with 22q11.2 Deletion Syndrome Associated with MCLMR

Microcephaly with or without chorioretinopathy, lymphedema, or mental retardation (MCLMR; OMIM 152950) is a rare autosomal dominantly inherited syndrome. Mutations in the kinesin family member 11 (KIF11) gene have been associated with this condition. Here, we report a de novo novel heterozygous missense mutation in exon 12 of the KIF11 gene [c.1402T>G; p.(Leu468Val)] in a boy with 22q11.2 microdeletion syndrome. His major features were microcephaly, ventricular septal defect, congenital lymphedema of the feet, and distinct facial appearance including upslanting palpebral fissures, a broad nose with rounded tip, anteverted nares, long philtrum with a thin upper lip, pointed chin, and prominent ears. His right eye was enucleated due to subretinal hemorrhage and retinal detachment at age 3 months. Lacunae of chorioretinal atrophy and the pale optic disc were present in the left eye. He also had a de novo 1.6-Mb microdeletion in the Di George/VCFS region of chromosome 22q11.2 in SNP array, which was confirmed by FISH analysis. In this study, for the first time, we describe the co-occurrence of a KIF11 mutation and 22q11.2 deletion syndrome in a patient with MCLMR.

S-trityl-L-cysteine, a novel Eg5 inhibitor, is a potent chemotherapeutic strategy in neuroblastoma

Eg5 is a member of the kinesin-5 family. It is involved in the formation of the bipolar spindle and serves a crucial role in mitosis; meaning that mitotic activation may serve as a chemotherapeutic strategy. However, the anticancer activity of Eg5 inhibitors in neuroblastoma remains uncharacterized. In the present study, the expression of Eg5 was examined in clinical tissue samples and neuroblastoma cell lines, SK-N-SH, SH-SY5Y and SK-N-BE2. Additionally, the antitumor activity of the Eg5 inhibitor, S-trityl-L-cysteine (STLC), was confirmed in vitro. STLC could mediate cell apoptosis, as well as cell cycle arrest, in a dose-dependent manner, which may contribute toward its antitumor activity. STLC-mediated apoptosis and cell cycle arrest were triggered by activation of the mitogen-activated protein kinase and nuclear factor kB signaling pathways. These results suggested that STLC may have potential in the in vivo treatment of neuroblastoma.

Familial Exudative Vitreoretinopathy: Pathophysiology, Diagnosis, and Management

Familial exudative vitreoretinopathy (FEVR) is a heritable vitreoretinopathy characterized by anomalous retinal vascular development. The principal feature of the disease is an avascular peripheral retina. This in turn can cause further pathological changes including neovascularization, exudation, hemorrhage, and retinal detachment. The biological basis of the disease is thought to be from defects in the Wnt signaling pathway. Many gene mutations have been implicated, and these can be inherited in an autosomal dominant (most common), autosomal recessive, and X-linked recessive fashion. Examination with wide-field fluorescein angiography is essential and can identify the disease in its earlier stages, enabling timely treatment, in addition to helping identify asymptomatic family members. The current treatment paradigm involves laser photocoagulation of the avascular peripheral retina for neovascular sequelae and vitreoretinal surgery for progressive retinal detachment. Further studies are underway to better characterize this complex vitreoretinopathy.

KIF20A expression as a prognostic indicator and its possible involvement in the proliferation of ovarian clear‑cell carcinoma cells

Kinesin family member 20A (KIF20A), which is involved in cytokinesis and intracellular transportation, has been recently reported to be upregulated in several malignancies and may contribute to chemotherapeutic resistance. We examined the distribution and expression of KIF20A in clear‑cell carcinoma (CCC) of the ovary to elucidate its clinical significance and molecular mechanism. Paraffin sections from ovarian CCC tissues (N=43) were immunostained with KIF20A antibody, and the staining intensities were semi‑quantitatively evaluated. Furthermore, we investigated whether silencing of KIF20A contributes to the proliferation‑inhibitory potential using CCC cells. During the observational period, 18 patients (41.9%) developed recurrence. The median time to recurrence was 11.5 months. Patients in the high KIF20A expression group showed poorer progression‑free survival (PFS) and overall survival (OS) than those in the low expression group (P=0.0443 and P=0.0478, respectively). In multivariable analyses, KIF20A expression was also a significantly independent indicator of PFS and a marginally significant indicator of OS [PFS: HR (high vs. low), 5.488; 95% CI, 1.410‑24.772 (P=0.0136); OS: HR, 2.835; 95% CI, 0.854‑11.035, (P=0.0897)]. In in vitro studies, the ovarian CCC cell proliferation was significantly decreased by KIF20A silencing or in the presence of KIF20A inhibitor in CCC cells. Cell cycle G2/M arrest and a higher apoptosis‑induced fraction were more frequently observed in si‑KIF20A‑transfected CCC cells than in the control cells. Although the present study was preliminary, these data indicate the possible involvement of KIF20A in the proliferation of CCC, suggesting that targeting this molecule may contribute to reversing the malignant potential consequently affecting the oncologic outcome of CCC patients.

Eg5 inhibitor YL001 induces mitotic arrest and inhibits tumor proliferation

Eg5 is a kinesin spindle protein that controls chromosomal segregation in mitosis and is thus a critical drug target for cancer therapy. We report the discovery of a potent, selective inhibitor of Eg5 designated YL001. YL001 was obtained through shape similarity based virtual screening, and it bears a 1,5-disubstituted tetrazole scaffold. YL001 exhibits favorable bioactivity in a variety of cancer cell lines, including taxol-resistant ovarian cancer and 6TG-resistant breast cancer cell lines. This compound inhibits tumor growth by 60% and significantly prolongs median survival time by more than 50% in a xenograft mouse model. YL001 blocks the ATPase activity of Eg5 and causes mitotic failure, ultimately resulting in apoptosis of cancer cells through activation of the caspase-3 pathway. Our findings demonstrate that YL001 is a potent antitumor agent that may be developed for cancer therapeutics.

Tracking cellular and molecular changes in a species-specific manner during experimental tumor progression in vivo

Hepatoblastoma (HBL) is a pediatric liver cancer with defined molecular alterations driving its progression. Here, we describe an animal model for HBL on the chick chorioallantoic membrane (CAM), which recapitulates relevant features of HBL in patients. Expression of classic tumor-associated proteins such as β-catenin, EpCAM and CK19 was maintained in acini-like organized tumors on CAM, as was synthesis of AFP, a tumor marker used for monitoring patient response. RNA sequencing revealed an unexpected molecular evolution of HBL cells on the CAM, with significant deregulation of more than 6,000 genes including more than half of all HOX genes. Bioinformatic analysis distinguish between tumor cell-expressed genes and chick genes, thereby shedding new light on the complex interactions taking place during HBL progression. Importantly, human tumor suppressive ribosomal genes were downregulated after implantation, whereas mitochondrial genes encoding for anti-apoptotic peptides were strongly induced in vivo. Meprin-1α expression was increased during evolution of CAM tumors and confirmed by immunohistochemistry. Cisplatin, a commonly used chemotherapeutic agent for HBL, showed significant anti-tumoral effects. Our results broaden the understanding of the molecular adaptation process of human cancer cells to the microenvironment and might help to elaborate novel therapeutic concepts for the treatment of this pediatric liver tumor.

Biological outcome and mapping of total factor cascades in response to HIF induction during regenerative angiogenesis

Hypoxia Inducible Factor (HIF) is the main transcription factor that mediates cell response to hypoxia. Howeverthe complex factor cascades induced by HIF during regenerative angiogenesis are currently incompletely mapped and the biological outcome mediated by chronic HIF induction during vessel regeneration are not well known. Here, we investigated the biological impact of HIF induction on vascular regeneration and identified the differentially regulated genes during regeneration, HIF induction and hypoxic regeneration. The use of the fin zebrafish regeneration model revealed that exposure to HIF inducer (cobalt chloride) prevents vessel differentiation by maintaining their vascular plexuses in an immature state. The regenerated fins are easily breakable, lacking completely endochondral ossification. Gene expression arrays combined to gene functional enrichment analysis revealed that regenerative process and HIF induction shared the regulation of common genes mainly involved in DNA replication and proteasome complex. HIF induction during regeneration affected the expression of exclusive genes involved in cell differentiation and communication, consistent with the observed immature vascular plexuses of the regenerated fins during HIF induction. The use of morpholino (MO) knockdown strategy revealed that the expression of some of these genes such as tubulin and col10a1 are required for fin regeneration. Taken together, this study revealed the impact of HIF induction on regenerative angiogenesis and provided a framework to develop a gene network leading to regenerative process during HIF expression.

High Eg5 expression predicts poor prognosis in breast cancer

Eg5 is a motor protein belonging to the kinesin-5 family and has been suggested to exert important function in tumors. In this study, we determined the mRNA and protein expression levels of Eg5 in cancerous and non-cancerous breast tissue by quantitative real-time polymerase chain reaction (qRT-PCR) and tissue microarray immunohistochemistry analysis (TMA-IHC) respectively. The results of 20 fresh-frozen BC samples demonstrated that Eg5 mRNA levels were significantly higher in BC tissues compared with corresponding non-cancerous tissue (p = 0.0009). TMA-IHC analysis in 127 BC tissues revealed that Eg5 expression obviously correlated with clinicopathologial parameters, including tumor grade (p = 0.004), ER status (p = 0.030), Ki67 status (p = 0.005), molecular classification (p = 0.026), N stage (p = 0.015), and TNM stage (p = 0.001). Kaplan-Meier survival curve indicated that high Eg5 expression (p = 0.012), Ki67 status (p = 0.014) and TNM stage (p = 0.026) were independent factors to predict poor prognosis for patients with breast cancer. Our data suggest that Eg5 is not only overexpressed in BC, it may be also served as a potential prognostic marker.

Eg5 Overexpression Is Predictive of Poor Prognosis in Hepatocellular Carcinoma Patients

Eg5 (kinesin spindle protein) plays an essential role in mitosis. Inhibition of Eg5 function results in cell cycle arrest at mitosis, which leads to cell death. To date, Eg5 expression and its prognostic significance have not been studied in hepatocellular carcinoma (HCC). In this study, 26 freshly frozen HCC tissue samples and matched peritumoral tissue samples were evaluated with a one-step qPCR test and immunohistochemical (IHC) analysis was conducted on 156 HCC samples to investigate the relationships among Eg5 expression, clinicopathological factors, and prognosis. Eg5 mRNA and protein expression levels were significantly higher in HCC tissues relative to matched noncancerous tissues (p < 0.05). High Eg5 protein expression was significantly related to liver cirrhosis (p = 0.038) and TNM stage (p = 0.008). Kaplan-Meier survival and Cox regression analyses revealed that Eg5 overexpression (p = 0.001), liver cirrhosis (p = 0.009), and TNM stage (p = 0.025) were independent prognostic factors for overall survival. These findings indicate that Eg5 expression can be used as a biomarker of poor prognosis and as a novel therapeutic target for HCC.

Kif4 regulates the expression of VEGFR1 through the PI3K/Akt signaling pathway in RAW264.7 monocytes/macrophages

Kinesin superfamily protein 4 (Kif4), a microtubule-based motor protein, has been shown to participate in a number of critical cellular processes, such as cell division, the intracellular transport of membranous vesicles and signal transduction. However, whether KIF4 regulates vascular endothelial growth factor (VEGF) receptor 1 (VEGFR1) expression remains unknown. Thus, in this study, in order to examine the effects of Kif4 on the expression of VEGFR1 in RAW264.7 monocytes/macrophages, Kif4 was silenced using siRNA. RT-qPCR, western blot analysis and ELISA were used to assess the expression of Kif4 and VEGFR1 up- and downstream signaling molecules, including VEGF-A, VEGFR1, soluble form of VEGFR1 (sVEGFR1), phosphorylated (p-)Akt and Akt. The silencing Kif4 inhibited the mRNA expression of VEGF (P<0.01) and p-Akt (P<0.05); however, the level of VEGF-A was increased (P<0.05) compared with the negative control siRNA-transfected group. The silencing of Kif4 decreased the VEGFR1 mRNA (P<0.05), VEGFR1 protein and sVEGFR1 levels in the cell supernatant (P<0.01). Following the application of insulin-like growth factor-1 (100 ng/ml), the specific agonist of PI3K/Akt in the Kif4 siRNA-transfected group, the VEGFR1 mRNA levels (P<0.001), the VEGFR1 protein levels and the sVEGFR1 (P<0.01) levels significantly increased; however, the levels of VEGF in the cell supernatant were decreased (P<0.05). Taken together, these findings suggest that Kif4 regulates the expression of VEGFR1 in RAW264.7 cells and that the PI3K/Akt pathway is involved in this process.

Overexpression of Kinesin Family Member 20A Correlates with Disease Progression and Poor Prognosis in Human Nasopharyngeal Cancer: A Retrospective Analysis of 105 Patients

BACKGROUND

Numerous studies have shown Kinesin family member 20A (KIF20A) may play a critical role in the development and progression of cancer. However, the clinical value of KIF20A in nasopharyngeal carcinoma (NPC) is unknown. Here, we investigated the expression pattern of KIF20A in NPC and its correlation with clinicopathological features of patients.

METHODS

Real-time PCR and Western blotting were used to quantify KIF20A expression in NPC cell lines and clinical specimens compared with normal controls. KIF20A protein expression was also examined in archived paraffin embedded tumor samples from 105 patients with pathologically confirmed NPC by immunohistochemistry (IHC). Statistical analyses were applied to assess the associations between KIF20A expression and the clinicopathological features and survival outcomes. Effects on migration and invasion were assessed by wound healing and transwell invasion assays after KIF20A silencing.

RESULTS

KIF20A was significantly overexpressed at both the mRNA and protein levels in NPC cell lines and human tumor tissues. 45/105 (42.9%) of NPC specimens expressed high levels of KIF20A among the KIF20A detectable cases. Statistical analysis revealed that high KIF20A expression was significantly associated with gender (P = 0.046), clinical stage (P<0.001), T category (P = 0.022), N category (P<0.001), distant metastasis (P = 0.001) and vital status (P = 0.001). Moreover, Higher KIF20A expression patients had shorter overall survival (OS) and progression-free survival (PFS) (P = 0.001 and P = 0.001; log-rank test). In multivariate analysis, KIF20A was an independent prognostic factor for OS and PFS in the entire cohort (P = 0.033, P = 0.008). Knock down of KIF20A expression significantly suppressed NPC cell's migration and invasion.

CONCLUSIONS

KIF20A is overexpressed and may serve as an independent prognostic biomarker in NPC. Targeting KIF20A reduces migration and invasion of NPC cells.

High Expression of KIF20A Is Associated with Poor Overall Survival and Tumor Progression in Early-Stage Cervical Squamous Cell Carcinoma

Background

The kinesin family member 20a (KIF20A) protein has been implicated in the development and progression of many human cancers; however, its precise function and role in cervical cancer remain largely unclear. This study aimed to investigate the expression profile and prognostic value of KIF20A in patients with early-stage cervical squamous cell carcinoma.

Methods

We examined the mRNA and protein levels of KIF20A in eight cervical cancer cell lines and eight paired cervical cancer samples, compared with normal cervical epithelial cells and adjacent normal cervical tissues, respectively. Immunohistochemistry was performed to detect the expression of KIF20A in paraffin-embedded specimens from 169 early-stage cervical squamous cell carcinoma patients. Statistical analyses were applied to analyze the association between KIF20A expression and clinical variables, as well with patient survival.

Results

The mRNA and protein expression levels of KIF20A were significantly elevated in cervical cancer cell lines and lesions compared with normal cells and corresponding normal tissues (P < 0.05). Immunohistochemistry analysis in 169 cervical cancer cases revealed that increased KIF20A expression was strongly associated with human papillomavirus (HPV) infection (P = 0.008), clinical stage (P = 0.001), tumor recurrence (P = 0.016), vital status (P < 0.001), the property of the surgical margin (P = 0.032), the lymphovascular space involvement (P = 0.014), and pelvic lymph node metastasis (P = 0.001). The overall survival and disease-free survival of patients with high levels of KIF20A expression were significantly poorer than those with low KIF20A expression. KIF20A was an independent survival prognostic factor, as evidenced by univariate and multivariate analysis.

Conclusions

Our results illustrate that elevated KIF20A expression correlates with HPV infection, clinical stage, tumor recurrence, lymphovascular space involvement, pelvic lymph node metastasis, and poor outcome in early-stage cervical squamous cell carcinoma patients. KIF20A aberrant expression is a novel independent unfavorable prognostic factor and may present a potential therapeutic target for cervical cancer.

The mitotic kinesin KIF11 is a driver of invasion, proliferation, and self-renewal in glioblastoma

The proliferative and invasive nature of malignant cancers drives lethality. In glioblastoma, these two processes are presumed mutually exclusive and hence termed "go or grow." We identified a molecular target that shuttles between these disparate cellular processes-the molecular motor KIF11. Inhibition of KIF11 with a highly specific small-molecule inhibitor stopped the growth of the more treatment-resistant glioblastoma tumor-initiating cells (TICs, or cancer stem cells) as well as non-TICs and impeded tumor initiation and self-renewal of the TIC population. Targeting KIF11 also hit the other arm of the "go or grow" cell fate decision by reducing glioma cell invasion. Administration of a KIF11 inhibitor to mice bearing orthotopic glioblastoma prolonged their survival. In its role as a shared molecular regulator of cell growth and motility across intratumoral heterogeneity, KIF11 is a compelling therapeutic target for glioblastoma.

Identification of novel KIF11 mutations in patients with familial exudative vitreoretinopathy and a phenotypic analysis

KIF11 gene mutations cause a rare autosomal dominant inheritable disease called microcephaly with or without chorioretinopathy, lymphedema, or mental retardation (MCLMR). Recently, such mutations were also found to be associated with familial exudative vitreoretinopathy (FEVR). Here, we report 7 novel KIF11 mutations identified by targeted gene capture in a cohort of 142 probands with FEVR who were diagnosed in our clinic between March 2015 and November 2015. These mutations were: p.L171V, c.790-2A>C, p.Q525*, p.Q842*, p.S936*, p.L983fs and p.R1025G. Phenotypic analysis revealed that all of the affected probands had advanced FEVR (stage 4 or above). Three had microcephaly, and one had chorioretinopathy, which indicated a phenotypic overlap with MCLMR. Two mutations were also found in the families of the affected probands. One parent with a p.R1025G mutation had an avascular peripheral retina and abnormal looping vessels. However, one parent with p.L983fs had normal retina, which indicated incomplete penetration of the genotype. Our results further confirmed that KIF11 is causative of FEVR in an autosomal dominant manner. We also suggest the examination of MCLMR-like features, such as microcephaly, chorioretinopathy, for patients with FEVR and wide-field fundus photography for patients with MCLMR in future practice.

Paclitaxel targets FOXM1 to regulate KIF20A in mitotic catastrophe and breast cancer paclitaxel resistance

FOXM1 has been implicated in taxane resistance, but the molecular mechanism involved remains elusive. In here, we show that FOXM1 depletion can sensitize breast cancer cells and mouse embryonic fibroblasts into entering paclitaxel-induced senescence, with the loss of clonogenic ability, and the induction of senescence-associated β-galactosidase activity and flat cell morphology. We also demonstrate that FOXM1 regulates the expression of the microtubulin-associated kinesin KIF20A at the transcriptional level directly through a Forkhead response element (FHRE) in its promoter. Similar to FOXM1, KIF20A expression is downregulated by paclitaxel in the sensitive MCF-7 breast cancer cells and deregulated in the paclitaxel-resistant MCF-7Tax(R) cells. KIF20A depletion also renders MCF-7 and MCF-7Tax(R) cells more sensitive to paclitaxel-induced cellular senescence. Crucially, resembling paclitaxel treatment, silencing of FOXM1 and KIF20A similarly promotes abnormal mitotic spindle morphology and chromosome alignment, which have been shown to induce mitotic catastrophe-dependent senescence. The physiological relevance of the regulation of KIF20A by FOXM1 is further highlighted by the strong and significant correlations between FOXM1 and KIF20A expression in breast cancer patient samples. Statistical analysis reveals that both FOXM1 and KIF20A protein and mRNA expression significantly associates with poor survival, consistent with a role of FOXM1 and KIF20A in paclitaxel action and resistance. Collectively, our findings suggest that paclitaxel targets the FOXM1-KIF20A axis to drive abnormal mitotic spindle formation and mitotic catastrophe and that deregulated FOXM1 and KIF20A expression may confer paclitaxel resistance. These findings provide insights into the underlying mechanisms of paclitaxel resistance and have implications for the development of predictive biomarkers and novel chemotherapeutic strategies for paclitaxel resistance.

No evidence of locus heterogeneity in familial microcephaly with or without chorioretinopathy, lymphedema, or mental retardation syndrome

BACKGROUND

Microcephaly with or without chorioretinopathy, lymphedema, or mental retardation syndrome (MCLMR) is a rare autosomal dominant disorder with variable expressivity. It is characterized by mild-to-severe microcephaly, often associated with intellectual disability, ocular defects and lymphedema. It can be sporadic or inherited. Eighty-seven patients have been described to carry a mutation in KIF11, which encodes a homotetrameric motor kinesin, EG5.

METHODS

We tested 23 unreported MCLMR index patients for KIF11. We also reviewed the clinical phenotypes of all our patients as well as of those described in previously published studies.

RESULTS

We identified 14 mutations, 12 of which are novel. We detected mutations in 12 affected individuals, from 6 out of 6 familial cases, and in 8 out of 17 sporadic patients. Phenotypic evaluation of patients (our 26 + 61 earlier published = 87) revealed microcephaly in 91%, eye anomalies in 72%, intellectual disability in 67% and lymphedema in 47% of the patients. Unaffected carriers were rare (4 out of 87: 5%). Family history is not a requisite for diagnosis; 31% (16 out of 52) were de novo cases.

CONCLUSIONS

All inherited cases, and 50% of sporadic cases of MCLMR are due to germline KIF11 mutations. It is possible that mosaic KIF11 mutations cause the remainder of sporadic cases, which the methods employed here were not designed to detect. On the other hand, some of them might have another mimicking disorder and genetic defect, as microcephaly is highly heterogeneous. In aggregate, KIF11 mutations likely cause the majority, if not all, of MCLMR.

Emerging microtubule targets in glioma therapy

Major advances in the genomics and epigenomics of diffuse gliomas and glioblastoma to date have not been translated into effective therapy, necessitating pursuit of alternative treatment approaches for these therapeutically challenging tumors. Current knowledge of microtubules in cancer and the development of new microtubule-based treatment strategies for high-grade gliomas are the topic in this review article. Discussed are cellular, molecular, and pharmacologic aspects of the microtubule cytoskeleton underlying mitosis and interactions with other cellular partners involved in cell cycle progression, directional cell migration, and tumor invasion. Special focus is placed on (1) the aberrant overexpression of βIII-tubulin, a survival factor associated with hypoxic tumor microenvironment and dynamic instability of microtubules; (2) the ectopic overexpression of γ-tubulin, which in addition to its conventional role as a microtubule-nucleating protein has recently emerged as a transcription factor interacting with oncogenes and kinases; (3) the microtubule-severing ATPase spastin and its emerging role in cell motility of glioblastoma cells; and (4) the modulating role of posttranslational modifications of tubulin in the context of interaction of microtubules with motor proteins. Specific antineoplastic strategies discussed include downregulation of targeted molecules aimed at achieving a sensitization effect on currently used mainstay therapies. The potential role of new classes of tubulin-binding agents and ATPase inhibitors is also examined. Understanding the cellular and molecular mechanisms underpinning the distinct behaviors of microtubules in glioma tumorigenesis and drug resistance is key to the discovery of novel molecular targets that will fundamentally change the prognostic outlook of patients with diffuse high-grade gliomas.