High Eg5 expression predicts poor prognosis in breast cancer

The mesenchymal morphology of cells expressing the EML4-ALK V3 oncogene is dependent on phosphorylation of Eg5 by NEK7

Echinoderm microtubule-associated protein-like 4 (EML4)-anaplastic lymphoma kinase (ALK) oncogenic fusion proteins are found in approximately 5% of non-small cell lung cancers. Different EML4-ALK fusion variants exist with variant 3 (V3) being associated with a significantly higher risk than other common variants, such as variant 1 (V1). Patients with V3 respond less well to targeted ALK inhibitors, have accelerated rates of metastasis, and have poorer overall survival. A pathway has been described downstream of EML4-ALK V3 that is independent of ALK catalytic activity but dependent on the NEK9 and NEK7 kinases. It has been proposed that assembly of an EML4-ALK V3-NEK9-NEK7 complex on microtubules leads to cells developing a mesenchymal-like morphology and exhibiting enhanced migration. However, downstream targets of this complex remain unknown. Here, we show that the microtubule-based kinesin, Eg5, is recruited to interphase microtubules in cells expressing EML4-ALK V3, whereas chemical inhibition of Eg5 reverses the mesenchymal morphology of cells. Furthermore, we show that depletion of NEK7 interferes with Eg5 recruitment to microtubules in cells expressing EML4-ALK V3 and cell length is reduced, but this is reversed by coexpression of a phosphomimetic mutant of Eg5, in a site, S1033, phosphorylated by NEK7. Intriguingly, we also found that expression of Eg5-S1033D led to cells expressing EML4-ALK V1 adopting a more mesenchymal-like morphology. Together, we propose that Eg5 acts as a substrate of NEK7 in cells expressing EML4-ALK V3 and Eg5 phosphorylation promotes the mesenchymal morphology typical of these cells.

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

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

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.

TRAF4 Inhibits the Apoptosis and Promotes the Proliferation of Breast Cancer Cells by Inhibiting the Ubiquitination of Spindle Assembly-Associated Protein Eg5

Tumor necrosis factor receptor associated factor 4 (TRAF4) is a RING domain E3 ubiquitin ligase that mediates the ubiquitination of various proteins and plays an important role in driving tumor progression. By studying the relationship between TRAF4 and Eg5, a member of the kinesin family that plays a critical role in spindle assembly, we demonstrated that TRAF4 regulated Eg5 ubiquitination and contributed to Eg5-mediated breast cancer proliferation and inhibited breast cancer apoptosis. TRAF4 and Eg5 were both highly expressed in breast cancer and their protein level was positively correlated. Relying on its Zinc fingers domain, TRAF4 interacted with Eg5 in the cytoplasm of breast cancer cells. TRAF4 was a mitosis-related protein, and by up-regulating the protein level of Eg5 TRAF4 participated in spindle assembly. Loss of TRAF4 resulted in monopolar spindles formation, but loss of function could be rescued by Eg5. Relying on its RING domain, TRAF4 up-regulated Eg5 protein levels by inhibition of Eg5 ubiquitination, thus stabilizing Eg5 protein level during mitosis. Furthermore, we found that Smurf2, a TRAF4-targeted ubiquitination substrate, mediated the regulation of Eg5 ubiquitination by TRAF4. TRAF4 inhibited the interaction between Smurf2 and Eg5, and down-regulated the protein level of Smurf2 by promoting its ubiquitination, thereby inhibited the Smurf2-catalyzed ubiquitination of Eg5 and up-regulated Eg5 protein levels. We also demonstrate that TRAF4 plays an important role in promoting cell proliferation and in inhibiting cell apoptosis induced by Eg5. In summary, our study suggests a new direction for investigating the role of TRAF4 in driving breast cancer progression.

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.

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.

Inhibitor library screening identifies ispinesib as a new potential chemotherapeutic agent for pancreatic cancers

Screening custom‐made libraries of inhibitors may reveal novel drugs for treating pancreatic cancer. In this manner, we identified ispinesib as a candidate and attempted to determine its clinical efficacy and the biological significance of its functional target Eg5 in pancreatic cancer. One hundred compounds in our library were screened for candidate drugs using cell cytotoxicity assays. Ispinesib was found to mediate effective antitumor effects in pancreatic cancer. The clinical significance of the expression of the ispinesib target Eg5 was investigated in 165 pancreatic cancer patients by immunohistochemical staining and in Eg5‐positive pancreatic cancer patient‐derived xenograft (PDX) mouse models. Patients with Eg5‐positive tumors experienced significantly poorer clinical outcomes than those not expressing Eg5 (overall survival; P < .01, recurrence‐free survival; P < .01). Ispinesib or Eg5 inhibition with specific siRNA significantly suppressed cell proliferation and induced apoptosis in pancreatic cancer cell lines. Mechanistically, ispinesib acted by inducing incomplete mitosis with nuclear disruption, resulting in multinucleated monoastral spindle cells. In the PDX mouse model, ispinesib dramatically reduced tumor growth relative to vehicle control (652.2 mm³ vs 18.1 mm³ in mean tumor volume, P < .01 by ANOVA; 545 mg vs 28 mg in tumor weight, P < .01, by ANOVA). Ispinesib, identified by inhibitor library screening, could be a promising novel therapeutic agent for pancreatic cancer. The expression of its target Eg5 is associated with poorer postoperative prognosis and is important for the clinical efficacy of ispinesib in pancreatic cancer.

Eg5 as a Prognostic Biomarker and Potential Therapeutic Target for Hepatocellular Carcinoma

BACKGROUND

The kinesin Eg5, a mitosis-associated protein, is overexpressed in many cancers. Here we explored the clinical significance of Eg5 in hepatocellular carcinoma (HCC).

METHODS

HCC tissues from surgical resection were collected. Total RNA was prepared from tumorous and nontumorous parts. Eg5 expression levels were correlated with overall survival (OS) and disease-free survival (DFS). In vitro efficacy of LGI-147, a specific Eg5 inhibitor, was tested in HCC cell lines. In vivo efficacy of Eg5 inhibition was investigated in a xenograft model.

RESULTS

A total of 108 HCC samples were included. The patients were divided into three tertile groups with high, medium, and low Eg5 expression levels. OS of patients with low Eg5 expression was better than that of patients with medium and high Eg5 expression (median, 155.6 vs. 75.3 vs. 57.7 months, p = 0.002). DFS of patients with low Eg5 expression was also better than that of patients with medium and high Eg5 expression (median, 126.3 vs. 46.2 vs. 39.4 months, p = 0.001). In multivariate analyses, the associations between Eg5 expression and OS (p < 0.001) or DFS remained (p < 0.001). LGI-147 reduced cell growth via cell cycle arrest and apoptosis and induced accumulation of abnormal mitotic cells. In the xenograft model, the tumor growth rate under LGI-147 treatment was significantly slower than under the control.

CONCLUSION

High Eg5 expression was associated with poor HCC prognosis. In vitro and in vivo evidence suggests that Eg5 may be a reasonable therapeutic target for HCC.

Future prospects for mitosis-targeted antitumor therapies

Dysregulation of cell cycle progression is a hallmark of cancer cells. In recent years, efforts have been devoted to the development of new therapies that target proteins involved in cell cycle regulation and mitosis. Novel targeted antimitotic drugs include inhibitors of aurora kinase family, polo-like kinase 1, Mps1, Eg5, CENP-5 and the APC/cyclosome complex. While certain new inhibitors reached the clinical trial stage, most were discontinued due to negative results. However, these therapies should not be readily dismissed. Based on recent advances concerning their mechanisms of action, new strategies could be devised to increase their efficacy and promote further clinical trials. Here we discuss three main lines of action to empower these therapeutic approaches: increasing cell death signals during mitotic arrest, targeting senescent cells and facilitating antitumor immune response through immunogenic cell death (ICD).

Identification of grade-related genes and construction of a robust genomic-clinicopathologic nomogram for predicting recurrence of bladder cancer

BACKGROUND

Bladder cancer (BC) is a common tumor in the urinary system with a high recurrence rate. The individualized treatment and follow-up after surgery is the key to a successful outcome. Currently, the surveillance strategies are mainly depending on tumor stage and grade. Previous evidence has proved that tumor grade was a significant and independent risk factor of BC recurrence. Exploring the grade-related genes may provide us a new approach to predict prognosis and guide the post-operative treatment in BC patients.

METHODS

In this study, the weighted gene co-expression network analysis was applied to identify the hub gene module correlated with BC grade using GSE71576. After constructing a protein-protein interaction (PPI) network with the hub genes inside the hub gene module, we identified some potential core genes. TCGA and another independent dataset were used for further validation.

RESULTS

The results revealed that the expression of AURKA, CCNA2, CCNB1, KIF11, TTK, BUB1B, BUB1, and CDK1 were significantly higher in high-grade BC, showing a strong ability to distinguish BC grade. The expression levels of the 8 genes in normal, paracancerous, tumorous, and recurrent bladder tissues were progressively increased. By conducting survival analysis, we proved their prognostic value in predicting the recurrence of BC. Eventually, we constructed a prognostic nomogram by combining the 8-core-gene panel with clinicopathologic features, which had shown great performance in predicting the recurrence of BC.

CONCLUSION

We identified 8 core genes that revealed a significant correlation with the tumor grade as well as the recurrence of BC. Finally, we proved the value of a novel prognostic nomogram for predicting the relapse-free survival of BC patients after surgery, which could guide their treatment and follow-up.

New pharmacological findings linked to biphenyl DHPMs, kinesin Eg5 ligands: anticancer and antioxidant effects

Background: Dihydropyrimidin-2-thiones (DHPMs) are a class of heterocyclic compound which have been intensively investigated mainly due to their anticancer activity as kinesin Eg5 inhibitors. Materials & methods: A library of N1 aryl substituted DHPMs were tested against glioma and bladder cancer cell lines. Quantitative structure-activity relationship (QSAR) investigation was performed in order to identify key elements of DHPMs linked with their antiproliferative effect. The toxicity of most active compounds was investigated using Caenorhabditis elegans as the model. Results & conclusion: DHPMs 9, 13 and 17 have been identified as having improved activity against glioma and bladder cell lines as compared with monastrol. Flow cytometry investigations showed that the new compounds induce cell cycle arrest in phase G₂/M and cell death by apoptosis. In addition, compound 13 was able to modulate the reactive oxygen species production in vivo in C. elegans. The biphenyl dihydropyrimidinthiones provided a safety profile in C. elegans.

High methionyl-tRNA synthetase expression predicts poor prognosis in patients with breast cancer

Aims

Methionyl–tRNA synthetase (MARS) is known to play a critical role in initiating translation and protection against cellular damages in vivo. The aim of this study was to clarify the role of MARS in breast cancer (BC) progression.

Methods

The expressions of MARS messenger RNA (mRNA) and protein in human BC tissues and adjacent non-cancerous tissues were detected by quantitative real-time PCR, western blot and immunohistochemistry. The prognostic potential of MARS in patients with BC was assessed by univariate and multivariate survival analyses. The association between the MARS expression and BC progression was further evaluated by the bioinformatics database of UALCAN, Gene Expression Profiling Interactive Analysis (GEPIA) and Gene Expression Database of Normal and Tumor Tissues (GENT). The role of MARS in the proliferation, migration and epithelial-to-mesenchymal transition (EMT) of human breast cancer cell line (MCF-7 cells) was investigated after siRNA transfection.

Results

The expression level of MARS mRNA in the fresh BC tissues was significantly higher than that in the adjacent tissues. Immunohistochemistry showed that the expression level of MARS was closely associated with the clinicopathologial parameters of patients with BC, including the HER-2 status, Ki-67 status, molecular classification, tumour grade, N stage and tumour, node, metastasis (TNM) stage, and this finding was further confirmed by UALCAN database. The Kaplan-Meier analysis showed that high MARS expression and TNM stage were predictors of poor prognosis of patients with BC. The proliferation, migration and EMT capabilities of MCF-7 cells were significantly suppressed after MARS knockdown. An overview of UALCAN, GEPIA and GENT results suggested that MARS may be an oncogene of BC, as well as a potential therapeutic target of this malignant tumour.

Conclusions

High expression level of MARS in the human BC tissues was significantly associated with the unfavourable prognosis of patients with BC, suggesting that MARS may serve as a potential prognostic marker for the clinical diagnosis and prognostic prediction of BC.

Suppression of KIF22 Inhibits Cell Proliferation and Xenograft Tumor Growth in Tongue Squamous Cell Carcinoma

Background

Oral carcinoma is the sixth most common cancer and is a serious public health problem, and tongue squamous cell carcinoma (TSCC) is the most common type of oral carcinoma. Kinesin family member 22 (KIF22), also called as kinesin-like DNA binding protein (KID), is a microtubule-based motor protein and binds to both microtubules and chromosomes, transporting organelles, protein, and mRNA. This research aimed at investigating the prognostic significance of KIF22 in TSCC. Patients and Methods. This retrospective research collected 82 paired tissues with TSCC. KIF22 protein expression level was detected by immunohistochemical staining. Suppression of KIF22 with shRNA in CAL-27 and SCC-15 cells was to observe cell proliferation in vitro and xenograft tumor growth in vivo.

Results

In TSCC tissues, the protein expression level of KIF22 was increased and correlated with tumor stage, clinical stage, and lymphatic metastasis (P=0.013, P=0.013, P=0.013,

Conclusion

KIF22 might play an important role in the progression of TSCC and could serve as a therapeutic target for TSCC.

Kinesin Eg5 Targeting Inhibitors as a New Strategy for Gastric Adenocarcinoma Treatment

The Kinesins are proteins involved in several biological processes such as mitosis, intracellular transport, and microtubule movement. The mitotic process is allowed by the correct formation of the mitotic spindle which consists of microtubules originating from the spindle poles. In recent years, kinesin Eg5 inhibitors were studied as new chemotherapeutic drugs, due to the lack of side effects and resistance mechanisms. The aim of this work was to investigate the molecular signaling underlying the administration of novel kinesis Eg5 inhibitors in an in vitro model of gastric adenocarcinoma. Data obtained from analogues of K858 led us to select compounds 2 and 41, due to their lower IC₅₀ values. The ability of kinesin inhibitors to induce apoptosis was investigated by evaluating Bax and Caspase-3 protein expression, evidencing that compound 41 and K858 markedly raise Bax expression, while only compounds 2 and 41 co-administrated with K858 trigger Caspase-3 activation. The inhibition of mitotic spindle was measured by β-tubulin immunofluorescence analysis revealing monopolar spindles formation in gastric cancer cells treated with compounds 2, 41, and K858. Nitric Oxide Synthase (NOS-2) and Matrix Metalloproteinase 9 (MMP-9) expression levels were measured finding a NOS-2-mediated downregulation of MMP-9 when compound 41 and K858 are co-administered. However, this is in contrast to what was reported by migration assay in which both novel compounds and K858 in monotherapy markedly reduce cell migration. This work remarks the importance of understanding and exploring the biological effects of different novel Eg5 kinesin inhibitors administered in monotherapy and in combination with K858 as potential strategy to counteract gastric cancer.

Suppression of KIF22 Inhibits Cell Proliferation and Xenograft Tumor Growth in Colon Cancer

Background: Kinesin family member 22 (KIF22) is known as a regulator of cell mitosis and cellular vesicle transport. The alterations of KIF22 are associated with a series of tumors; however, its possible role in the progression of colon cancer is still unclear. Materials and Methods: This retrospective research collected 82 paired tissues with colon cancer. KIF22 protein and mRNA expression levels were detected by immunohistochemistry assays and Immunoblot assays, respectively. Short hairpin RNA (shRNA) plasmids were used to suppress the expression of KIF22 in HCT116 and HT29 cells, and the silencing efficiencies of shRNA plasmids targeted KIF22 were detected by quantitative PCR assays and immunoblot assays. In addition, 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assays and xenograft tumor growth assays were performed to observe cell proliferation in vitro and in vivo. Results: In human colon cancer tissues, the expression level of KIF22 was increased and correlated with clinical pathological features, including tumor stage and clinical stage (p = 0.034, and p = 0.015, respectively). Suppression of KIF22 inhibited cell proliferation and xenograft tumor growth. Conclusion: KIF22 might play an important role in the regulation of cell proliferation in colon cancer and might therefore serve as a promising therapeutic target.

High kinesin family member 11 expression predicts poor prognosis in patients with clear cell renal cell carcinoma

Aims

Kinesin family member 11 (Kif11) is a member of the kinesin family motor proteins, which is associated with spindle formation and tumour genesis. In this study, we investigated the relationship between Kif11 expression and clear cell renal cell carcinoma (CCRCC) development.

Methods

The relationship between Kif11 expression and CCRCC development was analysed by quantitative real-time (qRT)-PCR analyses, and tissue immunohistochemistry. The prognostic significance of Kif11 expression was explored by univariable and multivariable survival analyses of 143 included patients. Furthermore, SB743921 was used as a specific Kif11 inhibitor to treat 786-O cells with the epithelial to mesenchymal transition (EMT) process analysed by qRT-PCR, and cell survival rates analysed with Annexin V-FITC/PI staining followed by flow cytometric analyses. Disease-free survival curves of Kif11 with different cancers and the relationships between Kif11 and the von Hippel-Lindau disease tumour suppressor gene (VHL), and proliferating cell nuclear antigen (PCNA) in kidney cancer were further analysed using the GEPIA database.

Results

The levels of Kif11 mRNA were significantly higher in CCRCC tissues compared with corresponding non-cancerous tissues. The results of immunohistochemistry demonstrated that the expression of Kif11 protein was significantly associated with clinicopathologial parameters, including nuclear grade and TNM stage. The Kaplan-Meier survival curve indicated that high Kif11 expression, nuclear grade and TNM stage were independent factors to predict poor prognosis in patients with CCRCC. In addition, inhibition of Kif11 expression by SB743921 suppressed cell proliferation, migration and the EMT process with increased apoptosis rate.

Conclusions

These results combined with bioinformation analyses suggest that high Kif11 expression was associated with unfavourable prognosis in CCRCC and could be used as a potential prognostic marker in the clinical diagnosis of CCRCC.

The balance of forces generated by kinesins controls spindle polarity and chromosomal heterogeneity in tetraploid cells

Chromosomal instability, one of the most prominent features of tumour cells, causes aneuploidy. Tetraploidy is thought to be an intermediate on the path to aneuploidy, but the mechanistic relationship between the two states is poorly understood. Here, we show that spindle polarity (e.g., bipolarity or multipolarity) in tetraploid cells depends on the level of functional phospho-Eg5, a mitotic kinesin, localised at the spindle. Multipolar spindles are formed in cells with high levels of phospho-Eg5. This process is suppressed by inhibition of Eg5 or expression of a non-phosphorylatable Eg5 mutant, as well as by changing the balance between opposing forces required for centrosome separation. Tetraploid cells with high levels of functional Eg5 give rise to a heterogeneous aneuploid population via multipolar division, whereas those with low levels of functional Eg5 continue to undergo bipolar division and remain tetraploid. Furthermore, Eg5 expression levels correlate with ploidy status in tumour specimens. We provide a novel explanation for the tetraploid intermediate model: spindle polarity and subsequent tetraploid cell behaviour are determined by the balance of forces generated by mitotic kinesins at the spindle.

Downregulation of TBC1 Domain Family Member 24 (BC1D24) Inhibits Breast Carcinoma Growth via IGF1R/PI3K/AKT Pathway

BACKGROUND TBC1 domain family member 24 (TBC1D24) pathogenic mutations affect its binding to ARF6 and then result in severe impairment of neuronal development. However, there are no reports about the expression and function of TBC1D24 in cancer. The aim of the present study was to evaluate the effect of proliferation, migration, and invasion after silencing TBC1D24 expression in breast cancer MCF-7 cells, and to elucidate the potential mechanism of TBC1D24 in breast cancer. MATERIAL AND METHODS The expression of TBC1D24 in breast cancer tissues and the adjacent non-tumor tissues was determined by S-P immunohistochemistry. The malignant behavior, including proliferation, migration, and invasion ability, was determined after silencing TBC1D24 in breast cancer MCF-7 cells. The expression of IGF1R was determined after silencing TBC1D24. The expression of TBC1D24 and IGF1R was detected after transfecting miR-30a mimics or inhibitors. The effect of TBC1D24 on MCF-7 cells growth in vivo was evaluated by a tumor xenograft study. RESULTS TBC1D24 expression was elevated and was associated with poor outcome in breast carcinoma. TBC1D24 high expression was significantly correlated with unfavorable OS and RFS for breast cancer patients (p<0.05). Silencing TBC1D24 inhibited the proliferation, migration, and invasion ability of MCF-7 cells. TBC1D24 and IGF1R expression were decreased when transfected with miR-30a mimics. However, TBC1D24 and IGF1R expression were increased when transfected with miR-30a inhibitors (p<0.05). Knockdown of TBC1D24 inhibited the expression of IGF1R, PI3K, and p-AKT (p<0.05). Knockdown of TBC1D24 abolished tumorigenicity of MCF-7 cells. The average volume and weight of tumors was lower after silencing TBC1D24 expression (P<0.05). CONCLUSIONS Silencing TBC1D24 inhibited MCF-7 cells growth in vitro and in vivo. TBC1D24 promoted breast carcinoma growth through the IGF1R/PI3K/AKT pathway. TBC1D24 is a potential therapeutic target for breast cancer.

Ubiquitin E3 Ligase MARCH7 promotes proliferation and invasion of cervical cancer cells through VAV2-RAC1-CDC42 pathway

Ubiquitin E3 Ligase MARCH7 is involved in T cell proliferation and neuronal development. In our previous study, we demonstrated MARCH7 promoted malignant behavior of ovarian cancer via the nuclear factor (NF)-κB and Wnt/β-catenin signaling pathway. However, the expression and function of MARCH7 in cervical cancer remains unknown. The present study aimed to unravel the expression and function of MARCH7 in cervical cancer to elucidate its potential role in the diagnosis and pathogenesis of cervical cancer. Results indicated that the expression of MARCH7 was abnormally high in cervical cancer tissues than normal cervical tissues. However, silencing the expression of MARCH7 in HeLa cells resulted in decreased cell proliferation and invasion. Mechanistic investigations revealed that MARCH7 interacted with VAV2. Silencing the expression of MARCH7 in HeLa cells inhibited the VAV2-RAC1-CDC42 signaling pathway. Overall, the results of the present study identified MARCH7 as a candidate oncogene in cervical cancer, and a potential target for cervical cancer therapy.

Eg5 orchestrates porcine oocyte maturational progression by maintaining meiotic organelle arrangement

Background

Kinesin superfamily proteins are microtubule-based molecular motors essential for the intracellular transport of various cargos, including organelles, proteins, and RNAs. However, their exact roles during mammalian oocyte meiosis have not been fully clarified.

Results

Herein, we investigated the critical events during porcine oocyte meiotic maturation with the treatment of Eg5-specific inhibitor monastrol. We found that Eg5 inhibition resulted in oocyte meiotic failure by displaying the poor expansion of cumulus cells and reduced rate of polar body extrusion. In the meantime, the spindle assembly and chromosome alignment were compromised, accompanied by the decreased level of acetylated α-tubulin, indicative of less stable microtubules. Impaired actin dynamics and mitochondria integrity were also observed in Eg5-inhibited oocytes. Additionally, inhibition of Eg5 caused the abnormal distribution of cortical granules and ovastacin, a cortical granule component, potentially leading to the fertilization failure.

Conclusions

Our findings reveal that Eg5 possesses an important function in porcine oocyte meiotic progression by regulating the organelle dynamics and arrangement.

ALG3 Is Activated by Heat Shock Factor 2 and Promotes Breast Cancer Growth

BACKGROUND Previous research found that ALG3 is associated with cervical cancer, but the role of ALG3 in breast cancer was still unknown. MATERIAL AND METHODS The expression of ALG3 in breast carcinoma tissues was determined by immunochemistry. The ability of cellular proliferation, migration, and invasion was determined by CCK-8 assay, wound healing migration assay, and cell invasion assays, respectively. The binding between HSF2 and promoter of ALG3 was determined by ChIP assay. RESULTS There was an increased expression of ALG3 in breast cancer tissues compared to normal breast tissues (p<0.05). High expression of ALG3 was significantly correlated with poor OS (p<0.05). ALG3 expression was significantly increased in cancer samples with advanced stages (stage III/IV) compared with those in the early stages of disease (stage I/II) (p<0.05). The staining intensity of ALG3 was significantly correlated to the tumor grade (grades 2-3 versus 1, p<0.05). Silencing ALG3 or HSF2 inhibited the proliferation, migration, and invasion abilities of MCF-7 cells. Silencing ALG3 retarded the growth of MCF-7 cells in vivo. CONCLUSIONS Silencing ALG3 inhibited MCF-7 cells growth in vitro and in vivo. HSF2 activated ALG3 and promoted the growth of breast carcinoma.

Asp1 Bifunctional Activity Modulates Spindle Function via Controlling Cellular Inositol Pyrophosphate Levels in Schizosaccharomyces pombe

The generation of two daughter cells with the same genetic information requires error-free chromosome segregation during mitosis. Chromosome transmission fidelity is dependent on spindle structure/function, which requires Asp1 in the fission yeast Schizosaccharomyces pombe Asp1 belongs to the diphosphoinositol pentakisphosphate kinase (PPIP5K)/Vip1 family which generates high-energy inositol pyrophosphate (IPP) molecules. Here, we show that Asp1 is a bifunctional enzyme in vivo: Asp1 kinase generates specific IPPs which are the substrates of the Asp1 pyrophosphatase. Intracellular levels of these IPPs directly correlate with microtubule stability: pyrophosphatase loss-of-function mutants raised Asp1-made IPP levels 2-fold, thus increasing microtubule stability, while overexpression of the pyrophosphatase decreased microtubule stability. Absence of Asp1-generated IPPs resulted in an aberrant, increased spindle association of the S. pombe kinesin-5 family member Cut7, which led to spindle collapse. Thus, chromosome transmission is controlled via intracellular IPP levels. Intriguingly, identification of the mitochondrion-associated Met10 protein as the first pyrophosphatase inhibitor revealed that IPPs also regulate mitochondrial distribution.

SPP1 promotes ovarian cancer progression via Integrin β1/FAK/AKT signaling pathway

OBJECTIVES

Ovarian cancer is one of the most lethal malignant tumors in women. Secreted phosphoprotein 1 (SPP1) plays an important role in some cancer types. Therefore, the role of SPP1 in ovarian cancer was determined and the potential mechanism was elucidated.

MATERIALS AND METHODS

The expression of SPP1 in ovarian cancer was determined by immunohistochemistry in ovarian cancer tissues and normal ovarian tissues. Cellular proliferation, migration, and invasion were determined by cell counting kit-8 assay, wound healing assay, and Matrigel invasion assay in SKOV3 and A2780 cells. The protein expression of SPP1, integrin subunit β1 (Integrin β1), focal adhesion kinase (FAK), and phosphorylation protein kinase B (p-AKT) was detected by Western blotting in SKOV3 cells after silencing SPP1. The expression of SPP1 was determined in SKOV3 cells after transfecting with miR-181a mimics or inhibitors. The growth of SKOV3 cells in vivo was determined in a nude mouse model of ovarian cancer after silencing SPP1.

RESULTS

The expression of SPP1 was higher in epithelial ovarian cancer tissues than in normal ovarian tissues. Silencing SPP1 decreased the cell proliferation, migration, and invasion. Ectopic expression of SPP1 increased the cell proliferation, migration, and invasion. Silencing SPP1 prevented ovarian cancer growth in mice. Silencing SPP1 inhibited Integrin β1/FAK/AKT pathway. In agreement, ectopically expressed SPP1 activated Integrin β1/FAK/AKT pathway. Also, SPP1 was regulated by miR-181a.

CONCLUSION

SPP1 is a biomarker for the prognosis of ovarian cancer. It is also oncogenic and a potential target for ovarian cancer therapy.