Spindle Protein Research Articles

First-in-human study of 4SC-205 (AEGIS), a novel oral inhibitor of Eg5 kinesin spindle protein.

2564 Background: 4SC-205 is a potent small molecule inhibitor of the kinesin spindle protein Eg5 with broad anti-tumour activity in vitro and in vivo. Currently, 4SC-205 is the only oral available ...

Nuclear Eg5 (kinesin spindle protein) expression predicts docetaxel response and prostate cancer aggressiveness.

Novel biomarkers predicting prostate cancer (PCa) aggressiveness and docetaxel therapy response of PCa patients are needed. In this study the correlation between nuclear Eg5-expression, PCa docetaxel response and PCa aggressiveness was assessed. Immunohistochemical staining for nuclear Eg5 was performed on 117 archival specimens from 110 PCa patients treated with docetaxel between 2004 and 2012. Samples were histologically categorized as positive/negative. Median follow-up time from diagnosis was 11.6 years. Nuclear Eg5-expression was significantly related to docetaxel response (p=0.036) in tissues acquired within three years before docetaxel initiation. Nuclear Eg5-expression was not related to Gleason-score (p=0.994). Survival of patients after docetaxel initiation did not differ based on nuclear Eg5-expression (p=0.540). Analyzing samples taken before hormonal therapy, overall survival and time to docetaxel use were significantly decreased in patients with nuclear Eg5-expressing tumors (p<0.01). Eg5-positive nuclei were found more frequently in T4-staged tumors (p=0.04), Gleason 8-10 tumors (p=0.08), and in metastasized tumors (p<0.01). Multivariate analyses indicated that nuclear Eg5-expression may be an independent parameter for tumor aggressiveness. Limitations of a retrospective analysis apply. In conclusion, nuclear Eg5-expression may be a predictive biomarker for docetaxel response in metastatic castrate-resistant PCa patients and a prognostic biomarker for hormone-naive PCa patients. Prospective validation studies are needed.

Optimization of diaryl amine derivatives as kinesin spindle protein inhibitors

Structure–activity relationship studies of diaryl amine-type KSP inhibitors were carried out. Diaryl amine derivatives with a pyridine ring or urea group were less active when compared with the parent carboline and carbazole derivatives. Optimization studies of a lactam-fused diphenylamine-type KSP inhibitor revealed that the aniline NH group and 3-CF3 phenyl group were indispensable for potent KSP inhibition. Modification with a seven-membered lactam-fused phenyl group and a 4-(trifluoromethyl)pyridin-2-yl group improved aqueous solubility while maintaining potent KSP inhibitory activity. From these studies, we identified novel diaryl amine-type KSP inhibitors with a favorable balance of potency and solubility.

Spindle and kinetochore-associated protein 1 is overexpressed in gastric cancer and modulates cell growth

Spindle and kinetochore-associated protein 1 (SKA1) is a microtubule-binding subcomplex of the outer kinetochore that is essential for proper chromosome segregation. SKA1 is required for timely anaphase onset during mitosis, when chromosomes undergo bipolar attachment on spindle microtubules leading to silencing of the spindle checkpoint. Recently, SKA1 has been highlighted as a biomarker in some types of cancers, however, the precise role of SKA1 in gastric cancer remains unknown. In order to investigate the role of SKA1 in gastric cancer, the expression levels of SKA1 were analyzed in 56 gastric cancer samples and 54 non-neoplastic samples by immunohistochemistry, and we found SKA1 was significantly overexpressed in gastric cancer tissues. Moreover, we employed lentivirus-mediated short hairpin RNA to knockdown SKA1 in the human gastric cancer cell line MGC80-3. Functional analysis indicated that SKA1 silencing significantly inhibited cell proliferation and colony formation, as determined by MTT and colony formation assays. The depletion of SKA1 in MGC80-3 cells also led to S phase cell cycle arrest. These results suggest that SKA1 could be used for gastric cancer early diagnosis as a biomarker. It is possible to enable a potential therapy based on targeting SKA1.

Kinesin spindle protein inhibitors with diaryl amine scaffolds: crystal packing analysis for improved aqueous solubility.

Diaryl amine derivatives have been designed and synthesized as novel kinesin spindle protein (KSP) inhibitors based on planar carbazole-type KSP inhibitors with poor aqueous solubility. The new generation of inhibitors was found to show comparable inhibitory activity and high selectivity for KSP, and this was accompanied with improved solubility. Kinetic analysis and molecular modeling studies suggested that these inhibitors work in an ATP-competitive manner via binding to the secondary allosteric site formed by α4 and α6 helices of KSP. Comparative structural investigations on a series of compounds revealed that the higher solubility of diaryl amine-type inhibitors was attributed to fewer van der Waals interactions in the crystal packing and the hydrogen-bond acceptor nitrogen of the aniline moiety for favorable solvation.

Delivery of kinesin spindle protein targeting siRNA in solid lipid nanoparticles to cellular models of tumor vasculature

The ideal siRNA delivery system should selectively deliver the construct to the target cell, avoid enzymatic degradation, and evade uptake by phagocytes. In the present study, we evaluated the importance of polyethylene glycol (PEG) on lipid-based carrier systems for encapsulating, and delivering, siRNA to tumor vessels using cellular models. Lipid nanoparticles containing different percentage of PEG were evaluated based on their physical chemical properties, density compared to water, siRNA encapsulation, toxicity, targeting efficiency and gene silencing in vitro. siRNA can be efficiently loaded into lipid nanoparticles (LNPs) when DOTAP is included in the formulation mixture. However, the total amount encapsulated decreased with increase in PEG content. In the presence of siRNA, the final formulations contained a mixed population of particles based on density. The major population which contains the majority of siRNA exhibited a density of 4% glucose, and the minor fraction associated with a decreased amount of siRNA had a density less than PBS. The inclusion of 10mol% PEG resulted in a greater amount of siRNA associated with the minor fraction. Finally, when kinesin spindle protein (KSP) siRNA was encapsulated in lipid nanoparticles containing a modest amount of PEG, the proliferation of endothelial cells was inhibited due to the efficient knock down of KSP mRNA. The presence of siRNA resulted in the formation of solid lipid nanoparticles when prepared using the thin film and hydration method. LNPs with a relatively modest amount of PEG can sufficiently encapsulate siRNA, improve cellular uptake and the efficiency of gene silencing.

Developments of Kinesin Spindle Protein Inhibitors as Antitumor Agents Based on the Five-membered Heterocycle Scaffolds

Kinesin spindle protein (KSP) plays an essential role in centrosome separation and formation of the bipolar mitotic spindle. Its exclusive involvement in the mitotic spindle of proliferating cells presents an opportunity for developing new anticancer agents with reduced side effects relative to antimitotics that target tubulin. Small molecule KSP inhibitors have demonstrated their potential as novel antimitotic agents. Several KSP inhibitors have progressed into clinical trials and many others are in preclinical developments. Recently, KSP inhibitors of wide structural diversity have appeared in literatures. This review will summarize the developments of KSP inhibitors based on the five-membered heterocycle scaffolds in recent 10 years. These small molecule KSP inhibitors were classified as dihydropyrazoles, dihydropyrroles, thiophenes, dihydrothiadiazoles, thiazoles and fused pyrroles, their structure-activity relationships were discussed.

Intracellular delivery of functionally active proteins using self-assembling pyridylthiourea-polyethylenimine

Intracellular delivery of functionally active proteins into cells is emerging as a novel strategy for research and therapeutic applications. Here, we present the properties of a self-assembling pyridylthiourea-modified polyethylenimine (πPEI), which interacts with proteins and promotes their delivery into the cytosol of mammalian cells. In aqueous medium at pH7.4, self-association of πPEI in the presence of green fluorescent proteins (GFP) leads to supramolecular protein-entrapped assemblies. These assemblies protect GFP from losing its fluorescence upon pH variation and assist delivery/translocation into the cytosol of mammalian cells via the endocytic pathway. The scope of application of this delivery system was extended to antibodies against intracellular targets as illustrated using a monoclonal antibody directed against the HPV-16 viral E6 oncoprotein and an antibody directed against the threonine-927 phosporylation site of the EG5 kinesin spindle protein. The πPEI-mediated delivery of native anti-E6 antibodies or anti-E6 antibodies equipped with a nuclear localization signal (NLS), led to regeneration of the p53 tumor suppression protein in E6-transformed CaSki cells. Delivery of functionally active anti-EG5 antibodies, with the same polymer, reduced HeLa cell viability and appeared to perturb, as expected, chromosome segregation during mitosis. Altogether, these results provide an easy to use delivery system for extending the scope of application of antibodies for epitope recognition within living cells and may provide novel opportunities for selective interference of cell function by a steric hindrance modality.

Bioengineered Bacterial Outer Membrane Vesicles as Cell-Specific Drug-Delivery Vehicles for Cancer Therapy

Advances in genetic engineering tools have contributed to the development of strategies for utilizing biologically derived vesicles as nanomedicines for achieving cell-specific drug delivery. Here, we describe bioengineered bacterial outer membrane vesicles (OMVs) with low immunogenicity that can target and kill cancer cells in a cell-specific manner by delivering small interfering RNA (siRNA) targeting kinesin spindle protein (KSP). A mutant Escherichia coli strain that exhibits reduced endotoxicity toward human cells was engineered to generate OMVs displaying a human epidermal growth factor receptor 2 (HER2)-specific affibody in the membrane as a targeting ligand. Systemic injection of siRNA-packaged OMVs caused targeted gene silencing and induced highly significant tumor growth regression in an animal model. Importantly, the modified OMVs were well tolerated and showed no evidence of nonspecific side effects. We propose that bioengineered OMVs have great potential as cell-specific drug-delivery vehicles for treating various cancers.

Simultaneous silencing of VEGF and KSP by siRNA cocktail inhibits proliferation and induces apoptosis of hepatocellular carcinoma Hep3B cells

BackgroundVascular endothelial growth factor (VEGF) is involved in the growth of new blood vessels that feed tumors and kinesin spindle protein (KSP) plays a critical role in mitosis involving in cell proliferation. Simultaneous silencing of VEGF and KSP, an attractive and viable approach in cancer, leads on restricting cancer progression. The purpose of this study is to examine the therapeutic potential of dual gene targeted siRNA cocktail on human hepatocellular carcinoma Hep3B cells.ResultsThe predesigned siRNAs could inhibit VEGF and KSP at mRNA level. siRNA cocktail showed a further downregulation on KSP mRNA and protein levels compared to KSP-siRNA or VEGF-siRNA, but not on VEGF expression. It also exhibited greater suppression on cell proliferation as well as cell migration or invasion capabilities and induction of apoptosis in Hep3B cells than single siRNA simultaneously. This could be explained by the significant downregulation of Cyclin D1, Bcl-2 and Survivin. However, no sigificant difference in the mRNA and protein levels of ANG2, involving inhibition of angiogenesis was found in HUVECs cultured with supernatant of Hep3B cells treated with siRNA cocktail, compared to that of VEGF-siRNA.ConclusionSilencing of VEGF and KSP plays a key role in inhibiting cell proliferation, migration, invasion and inducing apoptosis of Hep3B cells. Simultaneous silencing of VEGF and KSP using siRNA cocktail yields promising results for eradicating hepatocellular carcinoma cells, a new direction for liver cancer treatment.

ChemInform Abstract: Kinesin Spindle Protein (KSP) Inhibitors in Combination with Chemotherapeutic Agents for Cancer Therapy

AbstractReview: 134 refs.

Heterogeneity of outcome with single-agent carfilzomib: all relapsed/refractory myelomas are not created equal

Since the year 2000, there has been a continued improvement in survival outcomes for multiple myeloma (MM) patients,1 attributable to the clinical development and inclusion of novel agents in upfront therapy, and improvement in high-dose therapy administration.2 There has been a growing body of literature furthering the biological understanding of the disease. There is a clear recognition of both inter-patient and intra-patient genomic heterogeneity in multiple myeloma,3 although the academic community is still trying to comprehend specific phenotypic presentations such as primary plasma cell leukemia4 and extramedullary disease.5 Even with effective upfront therapeutic strategies, which seemingly help a greater proportion of MM patients achieve a ‘complete’ remission by biochemical and pathology criteria, relapses do occur sooner or later that require subsequent lines of therapy. There is a growing list of classes of novel agents that are disease-relevant and showing promise in early clinical investigations in the relapsed/refractory MM (RRMM) setting. These classes include histone deacytelase inhibitors, heat-shock protein inhibitors, kinesin spindle protein inhibitors, immune-therapeutics and ubiquitin-proteasome pathway targeting agents.6 We have witnessed the Food and Drug Administration approval of two novel agents in the past 12 months, namely carfilzomib and pomalidomide, in the RRMM setting. It is highly likely that several novel agents will acquire Food and Drug Administration approval for RRMM over the next 5 years. The challenges in this setting would then be to determine which class of drugs may be more suitable for an individual patient, whether it would be better to sequence or combine different drug classes, and whether or not it would be possible to achieve ‘functional cure’ by making RRMM a chronic disease for most patients.

New drugs and novel mechanisms of action in multiple myeloma in 2013: a report from the International Myeloma Working Group (IMWG).

Treatment in medical oncology is gradually shifting from the use of nonspecific chemotherapeutic agents toward an era of novel targeted therapy in which drugs and their combinations target specific aspects of the biology of tumor cells. Multiple myeloma (MM) has become one of the best examples in this regard, reflected in the identification of new pathogenic mechanisms, together with the development of novel drugs that are being explored from the preclinical setting to the early phases of clinical development. We review the biological rationale for the use of the most important new agents for treating MM and summarize their clinical activity in an increasingly busy field. First, we discuss data from already approved and active agents (including second- and third-generation proteasome inhibitors (PIs), immunomodulatory agents and alkylators). Next, we focus on agents with novel mechanisms of action, such as monoclonal antibodies (MoAbs), cell cycle-specific drugs, deacetylase inhibitors, agents acting on the unfolded protein response, signaling transduction pathway inhibitors and kinase inhibitors. Among this plethora of new agents or mechanisms, some are specially promising: anti-CD38 MoAb, such as daratumumab, are the first antibodies with clinical activity as single agents in MM. Moreover, the kinesin spindle protein inhibitor Arry-520 is effective in monotherapy as well as in combination with dexamethasone in heavily pretreated patients. Immunotherapy against MM is also being explored, and probably the most attractive example of this approach is the combination of the anti-CS1 MoAb elotuzumab with lenalidomide and dexamethasone, which has produced exciting results in the relapsed/refractory setting.

ARRY-520 Combined With Pomalidomide Displays Enhanced Anti-Tumor Activity In Preclinical Models Of Multiple Myeloma

Inhibitors of Kinesin Spindle Protein (KSP), a mitosis-specific motor protein, represent a novel class of targeted anti-cancer therapies that have demonstrated clinical activity in hematological cancers. Inhibition of KSP results in the formation of aberrant monopolar spindles, mitotic arrest, and rapid apoptosis through degradation of the survival protein Mcl-1. The majority of KSP-inhibitor sensitive cells are proliferating hematopoietic cells which are dependent on Mcl-1 for survival. ARRY-520, a highly selective KSP inhibitor, is currently in Phase 2 clinical studies in patients with relapsed and refractory multiple myeloma. To date, ARRY-520 has demonstrated a well-tolerated safety profile and clinical activity both alone and in combination with bortezomib, dexamethasone, or carfilzomib in heavily pretreated patients. Updated clinical data will be disclosed at this meeting in separate abstracts. While prior preclinical studies have shown that ARRY-520 is additive or synergistic when combined with bortezomib in several in vivo models of multiple myeloma, the combinability of ARRY-520 with other myeloma standards of care, such as immunomodulatory drugs (IMiD), has not been thoroughly investigated. In the present studies, we have evaluated the combination utility of ARRY-520 and pomalidomide, an IMiD recently approved by the FDA, in preclinical models of multiple myeloma. Our findings show that the combination of ARRY-520 (12.5 mg/kg, IP, D1, 2) with pomalidomide (10 mg/kg, IP, QD) is significantly more active than either monotherapy alone in several in vivo models of multiple myeloma. In particular, complete responses and cures were observed in two models. In the RPMI-8226 model, a 100% cure rate was observed with the combination regimen as compared to a 0% cure rate for either monotherapy (cure is defined as no palpable tumor 100 days from study initiation). Likewise, in the JJN3 model a 100% complete response rate was observed with the combination regimen versus a 0% complete response rate for either monotherapy (complete response is defined as no palpable tumor for 2 consecutive tumor measurements). Notably, similar combination efficacy was also observed in the RPMI-8226 model at full and significantly reduced doses of both ARRY-520 and pomalidomide, supporting a synergistic interaction between these drugs. Characterization of the mechanism underlying the anti-tumor activity of this combination is currently being explored. The combination regimen was well tolerated causing no significant enhancement of body weight loss (not exceeding 10% for any group). Additionally, hematology analysis showed that the combination regimen caused no significant increase in thrombocytopenia or leukopenia. Consistent with clinical findings, both single agent ARRY-520 and pomalidomide caused neutropenia while the combination of these drugs moderately enhanced these effects. Pharmacokinetic studies confirmed that administration of pomalidomide with ARRY-520 does not alter the exposure of either compound, suggesting that the mechanism of enhanced anti-tumor activity is dependent upon pharmacodynamic rather than pharmacokinetic effects. Taken together, these findings show that the novel combination of ARRY-520 and pomalidomide is a well-tolerated and synergistic preclinical regimen that warrants investigation in future clinical trials in patients with multiple myeloma. Disclosures:Humphries:Array BioPharma: Employment. Anderson:Array BioPharma: Employment. Williams:Array BioPharma: Employment. Rieger:Array BioPharma: Employment. Tunquist:Array BioPharma: Employment. Walker:Array BioPharma: Employment.

Phase 1 Study Of The Novel Kinesin Spindle Protein Inhibitor ARRY-520 + Carfilzomib (Car) In Patients With Relapsed and/Or Refractory Multiple Myeloma (RRMM)

Phase 1 Study Of The Novel Kinesin Spindle Protein Inhibitor ARRY-520 + Carfilzomib (Car) In Patients With Relapsed and/Or Refractory Multiple Myeloma (RRMM)

The Novel Human Double Minute (HDM)-2 Inhibitor DS-5272 Is Active Both Alone, and In Combination With Other Novel Agents, Against Multiple Myeloma

BackgroundThe ubiquitin-proteasome pathway is now a validated target for myeloma therapy given the regulatory approvals of proteasome inhibitors such as bortezomib and carfilzomib. Another logical set of targets are the E3 ligases, whose role is to facilitate the protein poly-ubiquitination typically needed for recognition by the constitutive or immunoproteasome prior to proteolysis. One of the more attractive such targets is HDM-2, the E3 ligase best known for its role in turnover of the p53 tumor suppressor, in part because p53 deletion or mutation is less common in myeloma than in solid tumors, and because it has been possible to develop agents targeting the HDM-2 p53 binding pocket. MethodsActivity of the specific HDM-2 inhibitor DS-5272 (Daiichi-Sankyo) was evaluated using a panel of p53 wild-type (wt) and mutant (mut) myeloma cell lines and also against primary patient samples. Studies were performed with DS-5272 both alone, and also in combination regimens with novel agents. Tetrazolium dye-based assays were employed to determine cell viability, Annexin V staining was used to examine apoptosis, and quantitative PCR and Western blotting were used to study selected transcripts and gene products, respectively. This study was supported in part by the M. D. Anderson Cancer Center SPORE in Multiple Myeloma. ResultsDS-5272 induced potent cytotoxicity in wt p53 MM1.S, H929, and MOLP-8 myeloma cell lines, with a median inhibitory concentration (IC50) in the single micromolar range, which was reproduced in studies of primary CD138+ plasma cells but not CD138- cells from myeloma patients. This cytotoxicity was both time- and concentration-dependent, and DS-5272 was more potent than the prototypical HDM-2 inhibitors, Nutlin-3a and MI-219. A dependence of DS-5272 activity on wt p53 was demonstrated by the much lower IC50 in the wt p53 than mut p53 cell lines, and the finding that suppression of p53 with a shRNA, as well as mutation of p53 with a sequence-specific zinc finger nuclease, significantly increased the IC50. Notably, DS-5272 remained active in the presence of conditioned media from stromal cells, or key myeloma cytokines such as IL-6. The reduced viability after exposure to DS-5272 was due at least in part to activation of type I cell death, as determined by increased staining for Annexin V, activation of caspases 9 and 3, and cleavage of PARP. Other downstream effects included induction of transcription of p21, Bax, HDM-2, NOXA, and PUMA. These proteins, as well as p27 and p53 were induced, while the abundance of Survivin, CHK1, Aurora A and B, PLK1, and KIF11 was reduced. Consistent with these latter effects, DS-5272 induced some accumulation of cells at the G2/M phase, and the appearance of cells with a disordered spindle. Suppression of KIF11 (kinesin spindle protein (KSP; Eg5)), which is responsible for centromere separation and bipolar spindle formation, seemed to occur through the binding of p21 to the cell cycle genes homology region (CHR) within the KIF11 promoter. Finally, combinations of DS-5272 with the specific KIF11 inhibitor Ispinesib produced enhanced G2/M arrest, as well as a synergistic reduction in cell viability with increased levels of apoptosis. ConclusionDS-5272 is a potent and novel agent with activity against multiple myeloma, and is active both alone and in rationally designed combination regimens with other drugs. These findings provide a rationale for the clinical translation of HDM-2 inhibitors as monotherapy, and possibly with other agents such as the KSP inhibitor ARRY-520, which is also active against myeloma, for patients with wt p53 relapsed and/or refractory myeloma. Disclosures:Cai:Daiichi-Sankyo Pharma Development: Employment, Equity Ownership. Seki:Daiichi Sankyo Co., Ltd.: Employment, Equity Ownership. Tse:Daiichi-Sankyo Pharma Development: Employment, Equity Ownership.

Expression of somatostatin receptors, angiogenesis and proliferation markers in pituitary adenomas: an immunohistochemical study with diagnostic and therapeutic implications

Pituitary adenomas are common intracranial neoplasms that generate symptoms as a result of either mass effect or the increased production of pituitary hormones. Although mostly benign, these tumours can be associated with considerable morbidity. We investigated a panel of immunohistochemical preparations to identify potential therapeutic targets and surrogate markers of clinical outcome. Tumour tissue from 25 patients was evaluated for immunohistochemical expression of somatostatin receptors 1‒5, von Willebrand-factor (vWF), interleukin-8 (IL-8), vascular endothelial growth factor receptor 2 (VEGFR-2), kinesin spindle protein (Eg5) and MIB-1 (Ki-67), and its relationship with clinical features was analysed. The proliferation marker MIB-1 (Ki-67) was the only marker predictive of adenoma recurrence. Of note, 67% of all relapses were associated with tumours showing luteinising hormone expression. All pituitary adenomas showed variable somatostatin receptor, IL-8, Eg5, vWF and VEGFR-2 expression; a relationship between these parameters and clinical outcome could not be demonstrated in this cohort. This study validates MIB-1 (Ki-67) as a reliable marker of tumour recurrence in pituitary adenomas. Considering the consistently increased expression of Eg5, IL-8, VEGFR-2, somatostatin receptors and vWF in these tumours, further investigation as potential therapeutic targets is warranted.

Radmis, a Novel Mitotic Spindle Protein that Functions in Cell Division of Neural Progenitors

Developmental dynamics of neural stem/progenitor cells (NSPCs) are crucial for embryonic and adult neurogenesis, but its regulatory factors are not fully understood. By differential subtractive screening with NSPCs versus their differentiated progenies, we identified the radmis (radial fiber and mitotic spindle)/ckap2l gene, a novel microtubule-associated protein (MAP) enriched in NSPCs. Radmis is a putative substrate for the E3-ubiquitin ligase, anaphase promoting complex/cyclosome (APC/C), and is degraded via the KEN box. Radmis was highly expressed in regions of active neurogenesis throughout life, and its distribution was dynamically regulated during NSPC division. In embryonic and perinatal brains, radmis localized to bipolar mitotic spindles and radial fibers (basal processes) of dividing NSPCs. As central nervous system development proceeded, radmis expression was lost in most brain regions, except for several neurogenic regions. In adult brain, radmis expression persisted in the mitotic spindles of both slowly-dividing stem cells and rapid amplifying progenitors. Overexpression of radmis in vitro induced hyper-stabilization of microtubules, severe defects in mitotic spindle formation, and mitotic arrest. In vivo gain-of-function using in utero electroporation revealed that radmis directed a reduction in NSPC proliferation and a concomitant increase in cell cycle exit, causing a reduction in the Tbr2-positive basal progenitor population and shrinkage of the embryonic subventricular zone. Besides, radmis loss-of-function by shRNAs induced the multipolar mitotic spindle structure, accompanied with the catastrophe of chromosome segregation including the long chromosome bridge between two separating daughter nuclei. These findings uncover the indispensable role of radmis in mitotic spindle formation and cell-cycle progression of NSPCs.

Gene expression and reproductive abilities of male Drosophila melanogaster subjected to ELF–EMF exposure

Extremely low frequency electromagnetic field (ELF–EMF) exposure is attracting increased attention as a possible disease-inducing factor. The in vivo effects of short-term and long-term ELF–EMF exposure on male Drosophila melanogaster were studied using transcriptomic analysis for preliminary screening and QRT-PCR for further verification.Transcriptomic analysis indicated that 439 genes were up-regulated and 874 genes were down-regulated following short-term exposures and that 514 genes were up-regulated and 1206 genes were down-regulated following long-term exposures (expression >2- or <0.5-fold, respectively). In addition, there are 238 up-regulated genes and 598 down-regulated genes in the intersection of short-term and long-term exposure (expression >2- or <0.5-fold). The DEGs (differentially expressed genes) in D. melanogaster following short-term exposures were involved in metabolic processes, cytoskeletal organization, mitotic spindle organization, cell death, protein modification and proteolysis. Long-term exposure let to changes in expression of genes involved in metabolic processes, response to stress, mitotic spindle organization, aging, cell death and cellular respiration. In the intersection of short-term and long-term exposure, a series of DEGs were related to apoptosis, aging, immunological stress and reproduction.To check the ELF–EMF effects on reproduction, some experiments on male reproduction ability were performed. Their results indicated that short-term ELF–EMF exposure may decrease the reproductive ability of males, but long-term exposures had no effect on reproductive ability. Down-regulation of ark gene in the exposed males suggests that the decrease in reproductive capacity may be induced by the effects of ELF–EMF exposure on spermatogenesis through the caspase pathway. QRT-PCR analysis confirmed that jra, ark and decay genes were down regulated in males exposed for 1 Generation (1G) and 72h, which suggests that apoptosis may be inhibited in vivo. ELF–EMF exposure may have accelerated cell senescence, as suggested by the down-regulation of both cat and jra genes and the up-regulation of hsp22 gene. Up-regulation of totA and hsp22 genes during exposure suggests that exposed flies might induce an in vivo immune response to counter the adverse effects encountered during ELF–EMF exposure. Down-regulation of cat genes suggests that the partial oxidative protection system might be restrained, especially during short-term exposures. This study demonstrates the bioeffects of ELF–EMF exposure and provides evidence for understanding the in vivo mechanisms of ELF–EMF exposure on male D. melanogaster.

Synthesis, biological evaluation and molecular docking studies of flavone and isoflavone derivatives as a novel class of KSP (kinesin spindle protein) inhibitors

The kinesin spindle protein (KSP) is involved in the formation of bipolar mitotic spindle during cell division and it becomes a new target to overcome the neurotoxicity of MTs inhibitors. A series of flavone and isoflavone derivatives (1a–7c) have been designed, synthesized and evaluated as potential KSP inhibitors. Among them, 2c displayed the most potent inhibitory activity in vitro, which inhibited the growth of MCF-7 and Hela cell lines with IC50 values of 4.8 and 4.3 μM, respectively, and also exhibited significant KSP inhibitory activity (IC50 = 0.023 μM). The new compounds can induce irregular monoastral spindles, the characteristic phenotype for KSP inhibiting agents. Docking simulation was further performed to determine the probable binding model.