Oxidative stress induces mitotic arrest by inhibiting Aurora A-involved mitotic spindle formation

Navigating the redox landscape: reactive oxygen species in regulation of cell cycle

Objectives: To advance our knowledge of disease mechanisms and therapeutic options, understanding cell cycle regulation is critical. Recent research has highlighted the importance of reactive oxygen species (ROS) in cell cycle regulation. Although excessive ROS levels can lead to age-related pathologies, ROS also play an essential role in normal cellular functions. Many cell cycle regulatory proteins are affected by their redox status, but the precise mechanisms and conditions under which ROS promote or inhibit cell proliferation are not fully understood.Methods: This review presents data from the scientific literature and publicly available databases on changes in redox state during the cell cycle and their effects on key regulatory proteins.Results: We identified redox-sensitive targets within the cell cycle machinery and analysed different effects of ROS (type, concentration, duration of exposure) on cell cycle phases. For example, moderate levels of ROS can promote cell proliferation by activating signalling pathways involved in cell cycle progression, whereas excessive ROS levels can induce DNA damage and trigger cell cycle arrest or cell death.Discussion: Our findings encourage future research focused on identifying redox-sensitive targets in the cell cycle machinery, potentially leading to new treatments for diseases with dysregulated cell proliferation.

Green-synthesized copper oxide nanoparticles induce apoptosis and up-regulate HOTAIR and HOTTIP in pancreatic cancer cells

Aim: Cu2O nanoparticles were synthesized using an extract from S. latifolium algae (SLCu2O NPs). Their effect on PANC-1 cells and the expression of two drug resistance-related lncRNAs were evaluated in comparison with Arsenic trioxide.Materials & methods: SLCu2O NPs were characterized using XRD, SEM, and TEM microscopies. The effects of SLCu2O NPs on cell cytotoxicity, cell cycle, and apoptosis, and expression of two drug resistance-related lncRNAs were examined using MTT assay, flow cytometry, and real-time PCR, respectively.Results: SLCu2O NPs demonstrated anti-cancer properties against PANC-1 cells comparable to Arsenic trioxide, and the expression of lncRNAs increased upon treatment with them.Conclusion: SLCu2O NPs demonstrate anti-cancer properties against PANC-1 cells; however, using gene silencing strategies along with SLCu2O NPs is suggested.

Oxidative Metabolism as a Cause of Lipid Peroxidation in the Execution of Ferroptosis

Ferroptosis is a type of nonapoptotic cell death that is characteristically caused by phospholipid peroxidation promoted by radical reactions involving iron. Researchers have identified many of the protein factors that are encoded by genes that promote ferroptosis. Glutathione peroxidase 4 (GPX4) is a key enzyme that protects phospholipids from peroxidation and suppresses ferroptosis in a glutathione-dependent manner. Thus, the dysregulation of genes involved in cysteine and/or glutathione metabolism is closely associated with ferroptosis. From the perspective of cell dynamics, actively proliferating cells are more prone to ferroptosis than quiescent cells, which suggests that radical species generated during oxygen-involved metabolism are responsible for lipid peroxidation. Herein, we discuss the initial events involved in ferroptosis that dominantly occur in the process of energy metabolism, in association with cysteine deficiency. Accordingly, dysregulation of the tricarboxylic acid cycle coupled with the respiratory chain in mitochondria are the main subjects here, and this suggests that mitochondria are the likely source of both radical electrons and free iron. Since not only carbohydrates, but also amino acids, especially glutamate, are major substrates for central metabolism, dealing with nitrogen derived from amino groups also contributes to lipid peroxidation and is a subject of this discussion.

Uptake, translocation, and metabolism of organophosphate esters (OPEs) in plants and health perspective for human: A review

Plant uptake, accumulation, and transformation of organophosphate esters (OPEs) play vital roles in their geochemical cycles and exposure risks. Here we reviewed the recent research advances in OPEs in plants. The mean OPE concentrations based on dry/wet/lipid weight varied in 4.80-3,620/0.287-26.8/12,000-315,000 ng g-1 in field plants, and generally showed positive correlations with those in plant habitats. OPEs with short-chain substituents and high hydrophilicity, particularly the commonly used chlorinated OPEs, showed dominance in most plant samples, whereas some tree barks, fruits, seeds, and roots demonstrated dominance of hydrophobic OPEs. Both hydrophilic and hydrophobic OPEs can enter plants via root and foliar uptake, and the former pathway is mainly passively mediated by various membrane proteins. After entry, different OPEs undergo diverse subcellular distributions and acropetal/basipetal/intergenerational translocations, depending on their physicochemical properties. Hydrophilic OPEs mainly exist in cell sap and show strong transferability, hydrophobic OPEs demonstrate dominant distributions in cell wall and limited migrations owing to the interception of Casparian strips and cell wall. Additionally, plant species, transpiration capacity, growth stages, commensal microorganisms, and habitats also affect OPE uptake and transfer in plants. OPE metabolites derived from various Phase I transformations and Phase II conjugations are increasingly identified in plants, and hydrolysis and hydroxylation are the most common metabolic processes. The metabolisms and products of OPEs are closely associated with their structures and degradation resistance and plant species. In contrast, plant-derived food consumption contributes considerably to the total dietary intakes of OPEs by human, particularly the cereals, and merits specifical attention. Based on the current research limitations, we proposed the research perspectives regarding OPEs in plants, with the emphases on their behavior and fate in field plants, interactions with plant-related microorganisms, multiple uptake pathways and mechanisms, and comprehensive screening analysis and risk evaluation.

Piperine improves the quality of porcine oocytes by reducing oxidative stress

Oxidative stress caused by light and high temperature arises during in vitro maturation (IVM), resulting in low-quality embryos compared with those obtained in vivo. To overcome this problem, we investigated the influence of piperine (PIP) treatment during maturation of porcine oocytes on subsequent embryo development in vitro. Porcine oocytes were cultured in IVM medium supplemented with 0, 50, 100, 200, or 400 μM PIP. After parthenogenetic activation, the blastocyst (BL) formation was significantly higher and the apoptosis rate was significantly lower using 200 μM PIP-treated oocytes (200 PIP). In the 200 PIP group, the level of reactive oxygen species at the metaphase II stage was decreased, accompanied by an increased level of glutathione and increased expression of antioxidant processes (Nrf2, CAT, HO-1, SOD1, and SOD2). Consistently, chromosome misalignment and aberrant spindle organization were alleviated and phosphorylated p44/42 mitogen-activated protein kinase activity was increased in the 200 PIP group. Expression of development-related (CDX2, NANOG, POU5F1, and SOX2), anti-apoptotic (BCL2L1 and BIRC5), and pro-apoptotic (BAK, FAS, and CASP3) processes was altered in the 200 PIP group. Ultimately, embryo development was improved in the 200 PIP group following somatic cell nuclear transfer. These findings suggest that PIP improves the quality of porcine oocytes by reducing oxidative stress, which inevitably arises via IVM. In-depth mechanistic studies of porcine oocytes will improve the efficiencies of assisted reproductive technologies.

Aurora kinase B disruption suppresses pathological retinal angiogenesis by affecting cell cycle progression

PURPOSE

The detrimental effects of pathological angiogenesis on the visual function are indisputable. Within a prominent role in chromosome segregation and tumor progression, aurora kinase B (AURKB) assumes a prominent role. However, its role in pathological retinal angiogenesis remains unclear. This study explores this latent mechanism.

METHODS

To inhibit AURKB expression, we designed specific small interfering RNAs targeting AURKB and transfected them into vascular endothelial cells. Barasertib was selected as the AURKB inhibitor. The anti-angiogenic effects of both AURKB siRNA and barasertib were assessed in vitro by cell proliferation, transwell migration, and tube formation. To evaluate the angiogentic effects of AURKB in vivo, neonatal mice were exposed to 75% oxygen followed by normoxic repositioning to establish an oxygen-induced retinopathy (OIR) model. Subsequently, phosphate-buffered saline and barasertib were administered into OIR mice via intravitreal injection. The effects of AURKB on cell cycle proteins were determined by western blot analysis.

RESULTS

We found that AURKB was overexpressed during pathological angiogenesis. AURKB siRNA and barasertib significantly inhibited endothelial cell proliferation, migration, and tube formation in vitro. Furthermore, AURKB inhibition attenuated retinal angiogenesis in the OIR model. A possible mechanism is the disruption of cell cycle by AURKB inhibition.

CONCLUSION

In conclusion, AURKB significantly influenced pathological retinal angiogenesis, thereby presenting a promising therapeutic target in ocular neovascular diseases.

Chitosan/alginate nanogel potentiate berberine uptake and enhance oxidative stress mediated apoptotic cell death in HepG2 cells

Biopolymer-based nanoscale drug delivery systems have become a promising approach to overcome the limitations associated with conventional chemotherapeutics used for cancer treatment. Herein, we reported to develop a hydrophilic nanogel (NG) composed of Chitosan (Chi) and sodium alginate (Alg) using the ion gelation method for delivering Berberine hydrochloride (BBR), an alkaloid obtained from Berberis aristata roots. The use of different nanocarriers for BBR delivery has been reported previously, but the bioavailability of these carriers was limited due to phagocytic uptake and poor systemic delivery. The developed NG showed enhanced stability and efficient entrapment of BBR ∼92 %, resulting in a significant increase in bioavailability. The pH-dependent release behavior demonstrated sustained and effective release of ∼86 %, ∼74 % and, ∼53 % BBR at pH 5.5, 6.6, and 7.4 respectively after 72h, indicating its potential as a drug carrier. Additionally, the cellular uptake of BBR was significantly higher ∼19 % in the BBR-NG (25 μM) than in bulk BBR (100 μM), leading to enhanced ROS generation, mitochondrial depolarisation, and inhibition of cell proliferation and colony formation in HepG2 cells. In summary, the results suggest that the Chi/Alg biopolymer-based nano-formulation could be an effective approach for delivering BBR and enhancing its cellular uptake, efficacy, and cytotoxicity.

Quantification of cellular phototoxicity of organelle stains by the dynamics of microtubule polymerization

Being able to quantify the phototoxicity of dyes and drugs in live cells allows biologists to better understand cell responses to exogenous stimuli during imaging. This capability further helps to design fluorescent labels with lower phototoxicity and drugs with better efficacy. Conventional ways to evaluate cellular phototoxicity rely on late-stage measurements of individual or different populations of cells. Here, we developed a quantitative method using intracellular microtubule polymerization as a rapid and sensitive marker to quantify early-stage phototoxicity. Implementing this method, we assessed the photosensitization induced by organelle dyes illuminated with different excitation wavelengths. Notably, fluorescent markers targeting mitochondria, nuclei, and endoplasmic reticulum exhibited diverse levels of phototoxicity. Furthermore, leveraging a real-time precision opto-control technology allowed us to evaluate the synergistic effect of light and dyes on specific organelles. Studies in hypoxia revealed enhanced phototoxicity of Mito-Tracker Red CMXRos that is not correlated with the generation of reactive oxygen species but a different deleterious pathway in low oxygen conditions.

Teaser

Microtubule dynamics in live cells allow quantification of cellular phototoxicity of fluorescent dyes in various conditions.

Pentagamavunone-1 inhibits aggressive breast cancer cell proliferation through mitotic catastrophe and ROS-mediated activities: in vitro and in vivo studies

Pentagamavunone-1 (PGV-1), an analog of curcumin, has been studied for its cytotoxic effects in 4T1, MCF7, MCF7/HER2, and T47D breast cancer cells. Its antiproliferative effect is partly mediated through G2/M arrest; however, its molecular mechanism during cell cycle progression remains unknown. In this study, we aimed to determine whether PGV-1 has any anticancer effects on highly aggressive breast cancer cells, with a focus on cell cycle regulatory activity, reactive oxygen species (ROS) generation, and their mediated effects on cancer cells. MDA-MB-231 (triple-negative) and HCC1954 (overexpressed HER2) immortalized human breast cancer cells were used in the study. PGV-1 exhibited cytotoxic activity with an irreversible antiproliferative impact on treated cells and had good selectivity when tested in fibroblast cells. Oral PGV-1 administration suppressed tumor growth in a cell-derived xenograft mouse model. PGV-1 induced the phosphorylation of Aurora A kinase and PLK1 in MDA-MB-231 cells, while PLK1 and cyclin B1 phosphorylation were enhanced in the PGV-1-treated HCC1954 cells during prometaphase arrest. Intracellular ROS production was substantially higher upon PGV-1 treatment following mitotic arrest, and this activity caused impairment of mitochondrial respiration, induced senescence, and subsequently triggered early-to-late apoptosis. Collectively, these results suggest that the molecular mechanism of PGV-1 involves the regulation of mitotic kinases to cause cell cycle arrest and the enhancement of ROS production to impair mitochondrial activity and induce cellular senescence. The therapeutic activities demonstrated by PGV-1 in this study show its potential as an appealing candidate for chemotherapy in breast cancer treatment.

Physiological mechanism of action and partial separation of herbicide-active compounds from the Diaporthe sp. extract on Amaranthus tricolor L

Thirteen fungi that produce compounds with herbicidal activities were isolated, identified, and extracted under the assumption that the mechanism of action occurs during seed exposure to the extract. The extracts from all the fungal strains considerably decreased the growth parameters of Amaranthus tricolor L. The EC010 strain extracts showed the greatest effect. Through ITS region gene sequencing methods, the isolated EC010 was identified as a genus of Diaporthe. The results showed a significant (p < 0.05) inhibitory effect of 91.25% on germination and a decrease in shoot and root length by 91.28% and 95.30%, respectively. The mycelium of Diaporthe sp. was extracted using sequential extraction techniques for the partial separation of the herbicidal fraction. According to the bioassay activities, the EtOAc fraction showed the highest inhibitory activity. The osmotic stress of the A. tricolor seeds was studied. Although the extract increased the accumulation of proline and soluble protein, the treated seeds showed lower imbibition. While the activity of α-amylase was dramatically decreased after treatment. A cytogenetic assay in the treated Allium cepa L. root revealed a decrease in the mitotic index, an altered mitotic phase index, and a promotion of mitotic abnormalities. Accordingly, the Diaporthe sp. may serve as a potential herbicidal compound resource.

Ferulic Acid Enhances Oocyte Maturation and the Subsequent Development of Bovine Oocytes

Improving the quality of oocytes matured in vitro is integral to enhancing the efficacy of in vitro embryo production. Oxidative stress is one of the primary causes of quality decline in oocytes matured in vitro. In this study, ferulic acid (FA), a natural antioxidant found in plant cell walls, was investigated to evaluate its impact on bovine oocyte maturation and subsequent embryonic development. Bovine cumulus-oocyte complexes (COCs) were treated with different concentrations of FA (0, 2.5, 5, 10, 20 μM) during in vitro maturation (IVM). Compared to the control group, supplementation with 5 μM FA significantly enhanced the maturation rates of bovine oocytes and the expansion of the cumulus cells area, as well as the subsequent cleavage and blastocyst formation rates after in vitro fertilization (IVF) and somatic cell nuclear transfer (SCNT). Furthermore, FA supplementation was observed to effectively decrease the levels of ROS in bovine oocytes and improve their mitochondrial function. Our experiments demonstrate that FA can maintain the levels of antioxidants (GSH, SOD, CAT) in oocytes, thereby alleviating the oxidative stress induced by H2O2. RT-qPCR results revealed that, after FA treatment, the relative mRNA expression levels of genes related to oocyte maturation (GDF-9 and BMP-15), cumulus cell expansion (HAS2, PTX3, CX37, and CX43), and embryo pluripotency (OCT4, SOX2, and CDX2) were significantly increased. In conclusion, these findings demonstrate that FA supplementation during bovine oocyte IVM can enhance oocyte quality and the developmental potential of subsequent embryos.

Development and Validation of a Novel Diagnostic Nomogram Model Using Serum Oxidative Stress Markers and AURKA for Prediction of Nasopharyngeal Carcinoma

Purpose

The mortality rate of nasopharyngeal carcinoma (NPC) remains high due to the absence of quick and accurate diagnostic approaches at its early stage. Our aim is to evaluate the diagnostic value of the elevated expression of Aurora kinase A (AURKA) and the oxidative stress markers (such as glutathione, superoxide dismutase and malondialdehyde) in serum of NPC patients and to establish a nomogram model for predicting NPC on the ground of these biomarkers.

Patients and Methods

Serum samples from 93 NPC patients and 94 healthy subjects were collected. Enzyme-linked immunosorbent assay (ELISA) was adopted to determine the AURKA level, while oxidative stress markers were measured by commercially available appropriate kits. Logistic regression was used for NPC predictor identification and nomogram construction. The training and validation cohorts (3:1) were randomly split up from the participants. Receiver operating characteristic (ROC) curves, calibration curves, and decision curve analyses (DCAs) were performed to validate the nomogram.

Results

AURKA and malondialdehyde (MDA) levels were significantly high in the NPC population compared to the healthy controls (P < 0.0001). The nomogram resulted in an area under the curve (AUC) of 0.897 (95% confidence interval: 0.848-0.947) in the training set and AUC of 0.770 (0.628-0.912) in the validation set. The predicted probability and the actual probability matched well in the nomogram (P > 0.05). DCAs showed good results too.

Conclusion

Serum levels of AURKA, SOD, and MDA have diagnostic values in NPC. The nomogram based on the identified biomarkers is favorable for NPC prediction.

A mitotic NADPH upsurge promotes chromosome segregation and tumour progression in aneuploid cancer cells

Redox metabolites have been observed to fluctuate through the cell cycle in cancer cells, but the functional impacts of such metabolic oscillations remain unknown. Here, we uncover a mitosis-specific nicotinamide adenine dinucleotide phosphate (NADPH) upsurge that is essential for tumour progression. Specifically, NADPH is produced by glucose 6-phosphate dehydrogenase (G6PD) upon mitotic entry, which neutralizes elevated reactive oxygen species (ROS) and prevents ROS-mediated inactivation of mitotic kinases and chromosome missegregation. Mitotic activation of G6PD depends on the phosphorylation of its co-chaperone protein BAG3 at threonine 285, which results in dissociation of inhibitory BAG3. Blocking BAG3T285 phosphorylation induces tumour suppression. A mitotic NADPH upsurge is present in aneuploid cancer cells with high levels of ROS, while nearly unobservable in near-diploid cancer cells. High BAG3T285 phosphorylation is associated with worse prognosis in a cohort of patients with microsatellite-stable colorectal cancer. Our study reveals that aneuploid cancer cells with high levels of ROS depend on a G6PD-mediated NADPH upsurge in mitosis to protect them from ROS-induced chromosome missegregation.

Aneugenic and clastogenic alterations in the DBA/IJ mouse model of rheumatoid arthritis treated with rituximab, an anti-CD20 antibody

Rheumatoid arthritis (RA), an autoimmune disorder in which the immune system attacks healthy cells, is associated with elevated risk of lymphoma. Rituximab, a treatment for non-Hodgkin's lymphoma, has been approved as a treatment for RA. We studied the effects of rituximab on chromosomal stability in collagen-induced arthritis DBA/1J animal models. Micronucleus levels were increased in the mouse models, mainly due to chromosome loss, as detected by fluorescence in situ hybridization; rituximab-treated arthritic mice had significantly less micronucleus formation. Serum 8-hydroxydeoxyguanosine, a DNA oxidative stress marker, was increased in the mice models but reduced following rituximab administration.

The promotion action of AURKA on post-ischemic angiogenesis in diabetes-related limb ischemia

Background

Diabetes-related limb ischemia is a challenge for lower extremity amputation. Aurora Kinase A (AURKA) is an essential serine/threonine kinase for mitosis, while its role in limb ischemia remains unclear.

Method

Human microvascular endothelial cells (HMEC-1) were cultured in high glucose (HG, 25 mmol/L d-glucose) and no additional growth factors (ND) medium to mimic diabetes and low growth factors deprivation as in vitro model. Diabetic C57BL/6 mice were induced by streptozotocin (STZ) administration. After seven days, ischemia was surgically performed by left unilateral femoral artery ligation on diabetic mice. The vector of adenovirus was utilized to overexpress AURKA in vitro and in vivo.

Results

In our study, HG and ND-mediated downregulation of AURKA impaired the cell cycle progression, proliferation, migration, and tube formation ability of HMEC-1, which were rescued by overexpressed AURKA. Increased expression of vascular endothelial growth factor A (VEGFA) induced by overexpressed AURKA were likely regulatory molecules that coordinate these events. Mice with AURKA overexpression exhibited improved angiogenesis in response to VEGF in Matrigel plug assay, with increased capillary density and hemoglobin content. In diabetic limb ischemia mice, AURKA overexpression rescued blood perfusion and motor deficits, accompanied by the recovery of gastrocnemius muscles observed by H&E staining and positive Desmin staining. Moreover, AURKA overexpression rescued diabetes-related impairment of angiogenesis, arteriogenesis, and functional recovery in the ischemic limb. Signal pathway results revealed that VEGFR2/PI3K/AKT pathway might be involved in AURKA triggered angiogenesis procedure. In addition, AURKA overexpression impeded oxidative stress and subsequent following lipid peroxidation both in vitro and in vivo, indicating another protective mechanism of AURKA function in diabetic limb ischemia. The changes in lipid peroxidation biomarkers (lipid ROS, GPX4, SLC7A11, ALOX5, and ASLC4) in in vitro and in vivo were suggestive of the possible involvement of ferroptosis and interaction between AUKRA and ferroptosis in diabetic limb ischemia, which need further investigation.

Conclusions

These results implicated a potent role of AURKA in diabetes-related impairment of ischemia-mediated angiogenesis and implied a potential therapeutic target for ischemic diseases of diabetes.

Aurora Kinase A Regulation by Cysteine Oxidative Modification

Aurora kinase A (AURKA), which is a member of serine/threonine kinase family, plays a critical role in regulating mitosis. AURKA has drawn much attention as its dysregulation is critically associated with various cancers, leading to the development of AURKA inhibitors, a new class of anticancer drugs. As the spatiotemporal activity of AURKA critically depends on diverse intra- and inter-molecular factors, including its interaction with various protein cofactors and post-translational modifications, each of these pathways should be exploited for the development of a novel class of AURKA inhibitors other than ATP-competitive inhibitors. Several lines of evidence have recently shown that redox-active molecules can modify the cysteine residues located on the kinase domain of AURKA, thereby regulating its activity. In this review, we present the current understanding of how oxidative modifications of cysteine residues of AURKA, induced by redox-active molecules, structurally and functionally regulate AURKA and discuss their implications in the discovery of novel AURKA inhibitors.

Inhibition of insulin-like growth factor-1 receptor enhances eribulin-induced DNA damage in colorectal cancer

Microtubule targeting agents (MTAs) such as taxanes are broadly used for the treatment of patients with cancer. Although MTAs are not effective for treatment of colorectal cancer (CRC), preclinical studies suggest that a subset of patients with CRC, especially those with cancers harboring the BRAF mutation, could benefit from such agents. However, two MTAs, eribulin (Eri) and vinorelbine, have shown limited clinical efficacy. Here, we report that insulin-like growth factor 1 receptor (IGF-1R) signaling is involved in Eri resistance. Using CRC cell lines, we showed that Eri induces activation and subsequent translocation of IGF-1R to the nucleus. When the activation and/or nuclear translocation of IGF-1R was inhibited, Eri induced DNA damage and enhanced G2 /M arrest. In a xenograft model using the Eri-resistant SW480 cell line, the combination of Eri and the IGF-1R inhibitor linsitinib suppressed tumor growth more efficiently than either single agent. Thus, our results indicated that combination dosing with Eri and an IGF-1R inhibitor could overcome Eri resistance and offer a therapeutic opportunity in CRC.

Bisimidazolium Salt Glycosyltransferase Inhibitors Suppress Hepatocellular Carcinoma Progression In Vitro and In Vivo

Hepatocellular carcinoma is a leading cause of cancer death, and the disease progression has been related to glycophenotype modifications. Previously synthesized bisimidazolium salts (C20 and C22) have been shown to selectively inhibit the activity of glycosyltransferases in cultured cancer cell homogenates. The current study investigated the anticancer effects of C20/C22 and the possible pathways through which these effects are achieved. The therapeutic value of C20/C22 in terms of inhibiting cancer cell proliferation, metastasis, and angiogenesis, as well as inducing apoptosis, were examined with hepatic cancer cell line HepG2 and a xenograft mouse model. C20/C22 treatment downregulated the synthesis of SLex and Ley sugar epitopes and suppressed selectin-mediated cancer cell metastasis. C20/C22 inhibited HepG2 proliferation, induced cell-cycle arrest, increased intracellular ROS level, led to ER stress, and eventually induced apoptosis through the intrinsic pathway. Furthermore, C20/C22 upregulated the expressions of death receptors DR4 and DR5, substantially increasing the sensitivity of HepG2 to TRAIL-triggered apoptosis. In vivo, C20/C22 effectively inhibited tumor growth and angiogenesis in the xenograft mouse model without adverse effects on major organs. In summary, C20 and C22 are new promising anti-hepatic cancer agents with multiple mechanisms in controlling cancer cell growth, metastasis, and apoptosis, and they merit further development into anticancer drugs.

Effects of aneuploidy on cell behaviour and function

Aneuploidy, a genomic alternation characterized by deviations in the copy number of chromosomes, affects organisms from early development through to aging. Although it is a main cause of human pregnancy loss and a hallmark of cancer, how aneuploidy affects cellular function has been elusive. The last two decades have seen rapid advances in the understanding of the causes and consequences of aneuploidy at the molecular and cellular levels. These studies have uncovered effects of aneuploidy that can be beneficial or detrimental to cells and organisms in an environmental context-dependent and karyotype-dependent manner. Aneuploidy also imposes general stress on cells that stems from an imbalanced genome and, consequently, also an imbalanced proteome. These insights provide the fundamental framework for understanding the impact of aneuploidy in genome evolution, human pathogenesis and drug resistance.

Gene Expression Analysis Reveals Key Genes and Signalings Associated with the Prognosis of Prostate Cancer

It is urgent to identify novel biomarkers for prostate cancer (PCa) prognosis and to understand the mechanisms regulating the tumorigenesis for PCa treatment. In this study, GSE17951 and TCGA were used to identify the differentially expressed genes (DEGs). Our study demonstrated that 1533 genes with increased expression and 2301 genes with decreased expression in PCa. Bioinformatics analysis data indicated that these up-regulated genes had an association with the modulation of mitotic nuclear division, sister chromatid cohesion, cell division, and cell cycle. Additionally, our results revealed downregulated genes took part in modulating extracellular matrix organization, angiogenesis, signal transduction, and Ras signaling pathway. Hub upregulated and downregulated PPI networks were identified by protein-protein interaction (PPI) network analysis and MCODE analysis. Of note, 12 cell cycle regulators, comprising CCNB1, CCNB2, PLK1, TTK, AURKA, CDC20, BUB1, PTTG1, CDC45, CDC25C, CCNA2, and BUB1B, were demonstrated to function crucially in PCa development. By detecting their expression in PCa cell lines, we confirmed that these cell cycle regulator expressions were heightened in PCa cells. GEPIA databases analysis showed that higher expression of these cell cycle regulators was correlated to shorter disease-free survival (DFS) time in PCa samples. Our findings collectively suggested targeting cell cycle pathways may offer novel prognosis and treatment biomarkers for PCa.

Aurora A kinase activation: Different means to different ends

Aurora A is a serine/threonine kinase essential for mitotic entry and spindle assembly. Recent molecular studies have revealed the existence of multiple, distinct mechanisms of Aurora A activation, each occurring at specific subcellular locations, optimized for cellular context, and primed by signaling events including phosphorylation and oxidation.

Melatonin Promotes In Vitro Maturation of Vitrified-Warmed Mouse Germinal Vesicle Oocytes, Potentially by Reducing Oxidative Stress through the Nrf2 Pathway

Simple Summary

Cryopreservation of oocytes can cause high oxidative stress, reduce the quality of vitrified-warmed oocytes, and seriously hinder the application of oocyte cryopreservation technology in production and medicine. In this work, we found for the first time that melatonin can exert antioxidant effects through receptors and regulate the Nrf2 antioxidant pathway to respond to oxidative stress of vitrified-warmed oocytes, thereby improving both oocyte quality and the potential for subsequent development. The results illustrated the molecular mechanism of melatonin’s antioxidant effect in vitrified-warmed oocytes and provided a theoretical basis for the application of melatonin in the cryopreservation of oocytes. These findings are of great significance for the further application of oocyte cryopreservation technology to production and assisted reproduction in the future.

Abstract

Previously it was reported that melatonin could mitigate oxidative stress caused by oocyte cryopreservation; however, the underlying molecular mechanisms which cause this remain unclear. The objective was to explore whether melatonin could reduce oxidative stress during in vitro maturation of vitrified-warmed mouse germinal vesicle (GV) oocytes through the Nrf2 signaling pathway or its receptors. During in vitro maturation of vitrified-warmed mouse GV oocytes, there were decreases (p < 0.05) in the development rates of metaphase I (MI) oocytes and metaphase II (MII) and spindle morphology grades; increases (p < 0.05) in the reactive oxygen species (ROS) levels; and decreases (p < 0.05) in expressions of Nrf2 signaling pathway-related genes (Nrf2, SOD1) and proteins (Nrf2, HO-1). However, adding 10⁻⁷ mol/L melatonin to both the warming solution and maturation solutions improved (p < 0.05) these indicators. When the Nrf2 protein was specifically inhibited by Brusatol, melatonin did not increase development rates, spindle morphology grades, genes, or protein expressions, nor did it reduce vitrification-induced intracellular oxidative stress in GV oocytes during in vitro maturation. In addition, when melatonin receptors were inhibited by luzindole, the ability of melatonin to scavenge intracellular ROS was decreased, and the expressions of genes (Nrf2, SOD1) and proteins (Nrf2, HO-1) were not restored to control levels. Therefore, we concluded that 10⁻⁷ mol/L melatonin acted on the Nrf2 signaling pathway through its receptors to regulate the expression of genes (Nrf2, SOD1) and proteins (Nrf2, HO-1), and mitigate intracellular oxidative stress, thereby enhancing in vitro development of vitrified-warmed mouse GV oocytes.

NEIL3 Prevents Senescence in Hepatocellular Carcinoma by Repairing Oxidative Lesions at Telomeres during Mitosis

Patients with hepatocellular carcinoma (HCC) suffer from few treatment options and poor survival rates. Here we report that endonuclease VIII-like protein 3 (NEIL3) is overexpressed in HCC and correlates with poor survival. All six HCC cell lines investigated were dependent on NEIL3 catalytic activity for survival and prevention of senescence, while NEIL3 was dispensable for nontransformed cells. NEIL3-depleted HCC cell lines accumulated oxidative DNA lesions specifically at telomeres, resulting in telomere dysfunctional foci and 53BP1 foci formation. Following oxidative DNA damage during mitosis, NEIL3 relocated to telomeres and recruited apurinic endonuclease 1 (APE1), indicating activation of base excision repair. META-FISH revealed that NEIL3, but not NEIL1 or NEIL2, is required to initiate APE1 and polymerase beta (POLB)-dependent base excision repair at oxidized telomeres. Repeated exposure of NEIL3-depleted cells to oxidizing damage induced chromatin bridges and damaged telomeres. These results demonstrate a novel function for NEIL3 in repair of oxidative DNA damage at telomeres in mitosis, which is important to prevent senescence of HCC cells. Furthermore, these data suggest that NEIL3 could be a target for therapeutic intervention for HCC. SIGNIFICANCE: This study describes compartmentalization of base excision repair during mitosis that is dependent on NEIL3, APE1, and POLB to repair oxidative damage accumulating at telomeres in hepatocellular carcinoma.

APC/C CDH1 ubiquitinates IDH2 contributing to ROS increase in mitosis

NADPH is a cofactor used by reactive oxygen species (ROS) scavenging enzymes to block ROS produced in cells. Recently, it was shown that in cancer cells, ROS progressively increases in tune to cell cycle leading to a peak in mitosis. Loss of IDH2 is known to cause severe oxidative stress in cell and mouse models as ROS increases in mitochondria. Therefore, we hypothesized that IDH2, a major NADPH-producing enzyme in mitochondria is ubiquitinated for ROS to increase in mitosis. To test this hypothesis, in cancer cells we examined IDH2 ubiquitination in mitosis and measured the ROS produced. We found that IDH2 is ubiquitinated in mitosis and on inhibiting anaphase-promoting complex/Cyclosome (APC/C) IDH2 was stabilized. Further, we observed that overexpressing APC/C coactivator CDH1 decreased IDH2, whereas depleting CDH1 decreased IDH2 ubiquitination. To understand the link between IDH2 ubiquitination and ROS produced in mitosis, we show that overexpressing mitochondria-targeted-IDH1 decreased ROS by increasing NADPH in IDH2 ubiquitinated cells. We conclude that APC/C CDH1 ubiquitinates IDH2, a major NADPH-producing enzyme in mitochondria contributing to ROS increase in mitosis. Based on our results, we suggest that mitosis can be a therapeutic window in mutant IDH2-linked pathologies.

Antitumor activity of a novel Aurora A/B kinases inhibitor TY-011 against gastric cancer by inducing DNA damage

TY-011, a novel Aurora A/B kinases inhibitor, was found in our previous study to exhibit prominent inhibitory effects on growth of gastric cancer, both in vitro and in vivo. To clarify the mechanisms of TY-011 in inhibiting proliferation of gastric cancer cells, the effects of TY-011 on mitosis, cell cycle, apoptosis and cellular DNA were checked in the present study. Our results showed that TY-011 treatment induced aberrant mitosis, G2/M phase arrest and apoptosis. Importantly, TY-011 induced evident DNA damage in MGC-803 and MKN-45 human gastric cancer cells, which was further characterized as DNA double-strand break. Furthermore, cells treated with TY-011 appeared to generate multiple spindle fibers emanating from several spindle poles, leading to poly-merotelic kinetochore. These results suggested that TY-011 induced abnormal microtubule-kinetochores attachment and thus DNA damage, apoptosis and finally inhibition of cell proliferation of human gastric cancer cells.

The Phosphorylation Status of Drp1-Ser637 by PKA in Mitochondrial Fission Modulates Mitophagy via PINK1/Parkin to Exert Multipolar Spindles Assembly during Mitosis

Mitochondrial fission and fusion cycles are integrated with cell cycle progression. Here we first re-visited how mitochondrial ETC inhibition disturbed mitosis progression, resulting in multipolar spindles formation in HeLa cells. Inhibitors of ETC complex I (rotenone, ROT) and complex III (antimycin A, AA) decreased the phosphorylation of Plk1 T210 and Aurora A T288 in the mitotic phase (M-phase), especially ROT, affecting the dynamic phosphorylation status of fission protein dynamin-related protein 1 (Drp1) and the Ser637/Ser616 ratio. We then tested whether specific Drp1 inhibitors, Mdivi-1 or Dynasore, affected the dynamic phosphorylation status of Drp1. Similar to the effects of ROT and AA, our results showed that Mdivi-1 but not Dynasore influenced the dynamic phosphorylation status of Ser637 and Ser616 in Drp1, which converged with mitotic kinases (Cdk1, Plk1, Aurora A) and centrosome-associated proteins to significantly accelerate mitotic defects. Moreover, our data also indicated that evoking mito-Drp1-Ser637 by protein kinase A (PKA) rather than Drp1-Ser616 by Cdk1/Cyclin B resulted in mitochondrial fission via the PINK1/Parkin pathway to promote more efficient mitophagy and simultaneously caused multipolar spindles. Collectively, this study is the first to uncover that mito-Drp1-Ser637 by PKA, but not Drp1-Ser616, drives mitophagy to exert multipolar spindles formation during M-phase.

Induction of microtubule hyper stabilization and robust G2 /M arrest by N-4-CN in human breast carcinoma MDA-MB-231 cells

AIM

Elucidation of the antiproliferative efficacy and mechanism of action of a design-optimized noscapine analog, N-4-CN.

METHODS

Cell viability was studied using an MTT assay. The drug-tubulin interactions were investigated using spectrofluorometry. The architectural defects, hyper stabilization, and recovery competence of cellular microtubules were studied using immunofluorescence microscopy. DCF-DH and rhodamine 123 were used as probes to to examine the levels of reactive oxygen species and the loss of mitochondrial membrane potential, respectively. Flow cytometry revealed the cell cycle progression pattern of the drug-treated cells.

KEY FINDINGS

Among the cell lines tested, N-4-CN showed the strongest inhibition of the viability of the triple-negative breast cancer (TNBC) cell line MDA-MB-231(IC₅₀ , 2.7 ± 0.1 µmol/L) and weakest inhibition of the noncancerous epithelial cell line, VERO (IC₅₀ , 60.2 ± 3 µmol/L). It perturbed tertiary structure of tubulin and stabilized colchicine binding to the protein. In cells, N-4-CN hyperstabilized the microtubules, and prevented the recovery of cold-depolymerized microtubules. Its multitude of effects on tubulin and microtubules facilitated cell cycle arrest and subsequent cell death that were complemented by elevated levels of reactive oxygen species (ROS).

SIGNIFICANCE

Owing to its ability to perturb a well-defined cancer drug target, tubulin, and to promote ROS-facilitated apoptosis, N-4-CN could be investigated further as a potential therapeutic against many neoplasms, including TNBC.

African Swine Fever Virus Structural Protein p17 Inhibits Cell Proliferation through ER Stress-ROS Mediated Cell Cycle Arrest

African swine fever virus (ASFV) is a highly pathogenic large DNA virus that causes African swine fever (ASF) in domestic pigs and wild boars. The p17 protein, encoded by the D117L gene, is a major transmembrane protein of the capsid and the inner lipid envelope. The aim of this study was to investigate the effects of p17 on cell proliferation and the underlying mechanisms of action. The effects of p17 on cell proliferation, cell cycle, apoptosis, oxidative stress, and endoplasmic reticulum (ER) stress have been examined in 293T, PK15, and PAM cells, respectively. The results showed that p17 reduced cell proliferation by causing cell cycle arrest at G2/M phase. Further, p17-induced oxidative stress and increased the level of intracellular reactive oxygen species (ROS). Decreasing the level of ROS partially reversed the cell cycle arrest and prevented the decrease of cell proliferation induced by p17 protein. In addition, p17-induced ER stress, and alleviating ER stress decreased the production of ROS and prevented the decrease of cell proliferation induced by p17. Taken together, this study suggests that p17 can inhibit cell proliferation through ER stress and ROS-mediated cell cycle arrest, which might implicate the involvement of p17 in ASF pathogenesis.

Are redox changes a critical switch for mitotic progression?

Cell-cycle dependent redox changes result in increased protein oxidation in mitotic cells. We show that oxidative modifications of a conserved cysteine residue within Aurora A kinase (AURKA) can promote its activation during mitosis. Targeting redox-sensitive cysteine residues within AURKA may lead to the development of novel anti-cancer agents with improved clinical efficacy.

Redox priming promotes Aurora A activation during mitosis

Cell cycle-dependent redox changes can mediate transient covalent modifications of cysteine thiols to modulate the activities of regulatory kinases and phosphatases. Our previously reported finding that protein cysteine oxidation is increased during mitosis relative to other cell cycle phases suggests that redox modifications could play prominent roles in regulating mitotic processes. The Aurora family of kinases and their downstream targets are key components of the cellular machinery that ensures the proper execution of mitosis and the accurate segregation of chromosomes to daughter cells. In this study, x-ray crystal structures of the Aurora A kinase domain delineate redox-sensitive cysteine residues that, upon covalent modification, can allosterically regulate kinase activity and oligomerization state. We showed in both Xenopus laevis egg extracts and mammalian cells that a conserved cysteine residue within the Aurora A activation loop is crucial for Aurora A activation by autophosphorylation. We further showed that covalent disulfide adducts of this residue promote autophosphorylation of the Aurora A kinase domain. These findings reveal a potential mechanistic link between Aurora A activation and changes in the intracellular redox state during mitosis and provide insights into how novel small-molecule inhibitors may be developed to target specific subpopulations of Aurora A.

Aurora A regulation by reversible cysteine oxidation reveals evolutionarily conserved redox control of Ser/Thr protein kinase activity

Reactive oxygen species (ROS) are physiological mediators of cellular signaling and play potentially damaging roles in human diseases. In this study, we found that the catalytic activity of the Ser/Thr kinase Aurora A was inhibited by the oxidation of a conserved cysteine residue (Cys290) that lies adjacent to Thr288, a critical phosphorylation site in the activation segment. Cys is present at the equivalent position in ~100 human Ser/Thr kinases, a residue that we found was important not only for the activity of human Aurora A but also for that of fission yeast MAPK-activated kinase (Srk1) and PKA (Pka1). Moreover, the presence of this conserved Cys predicted biochemical redox sensitivity among a cohort of human CAMK, AGC, and AGC-like kinases. Thus, we predict that redox modulation of the conserved Cys290 of Aurora A may be an underappreciated regulatory mechanism that is widespread in eukaryotic Ser/Thr kinases. Given the key biological roles of these enzymes, these findings have implications for understanding physiological and pathological responses to ROS and highlight the importance of protein kinase regulation through multivalent modification of the activation segment.

Aurora kinase mRNA expression is reduced with increasing gestational age and in severe early onset fetal growth restriction

INTRODUCTION

Oxidative damage and biochemical ageing are implicated in placental dysfunction and potentially fetal death. Cellular senescence may play a role in the pathophysiology of fetal growth restriction (FGR) and preeclampsia (PE). Aurora kinases (AURKA, B and C) are important regulators of cellular division in mitosis and meiosis with implications in cellular senescence. We aimed to investigate whether aurora kinase expression is altered with placental dysfunction or placental ageing.

METHODS

Placenta and blood was obtained across gestation from pregnancies complicated by PE, FGR or both PE and FGR, as well as gestation-matched control samples. Expression of AURKA, B and C mRNA was examined using real time qPCR in both the placenta and maternal circulation.

RESULTS

Placental aurora kinase expression decreased as gestation progressed: AURKA and AURKB were significantly reduced at 37-40 weeks, whereas AURKC was significantly reduced at 34-37 weeks, when compared to <34 weeks. In the maternal circulation, the mRNA level of AURKB was significantly reduced at >40 weeks compared to <34 weeks gestation. A significant reduction in AURKC was seen in FGR pregnancies <34 weeks compared to gestation-matched controls.

CONCLUSION

Placental AURK expression is reduced with increased gestation. Circulating AURKB mRNA reduces at >40 weeks gestation, when compared to <34 weeks. AURKC is significantly reduced in placentas from pregnancies complicated by severe early onset (<34 weeks) FGR compared with gestation-matched controls. The functional role of aurora kinase in the placenta and in gestational age warrants further investigation.

AURKA Enhances Autophagy of Adipose Derived Stem Cells to Promote Diabetic Wound Repair via Targeting FOXO3a

AURKA regulates apoptosis and autophagy in a diverse range of diseases and exhibits promising clinical efficacy; however, the role of AURKA in regulating adipose-derived stem cells (ADSCs) and repairing diabetic wound remains unclear. Here, we showed that ADSCs subjected to high glucose stress displayed an obvious induction of AURKA and FOXO3a, and a significant increase in autophagy and apoptosis. AURKA was confirmed to regulate autophagy through FOXO3a. AURKA-mediated autophagy inhibited high-glucose-induced apoptosis of ADSCs. Furthermore, co-immunoprecipitation and chromatin immunoprecipitation assays were employed to investigate the interaction of AURKA and FOXO3a. FOXO3a bound to its own promoter and transactivated its own expression. AURKA was found to interact with FOXO3a to regulate FOXO3a activity. In diabetic mice, ADSCs overexpressing AURKA led to a decrease of apoptosis of ADSCs and promoted wound healing in the skin. Taken together, our data suggest that transcriptional regulation of FOXO3a by high-glucose-mediated AURKA is necessary for ADSCs autophagy. Our data reveal a potential therapeutic strategy for targeting AURKA involved in high-glucose-induced anti-apoptotic autophagy in ADSCs.

Covalent Aurora A regulation by the metabolic integrator coenzyme A

Aurora A kinase is a master mitotic regulator whose functions are controlled by several regulatory interactions and post-translational modifications. It is frequently dysregulated in cancer, making Aurora A inhibition a very attractive antitumor target. However, recently uncovered links between Aurora A, cellular metabolism and redox regulation are not well understood. In this study, we report a novel mechanism of Aurora A regulation in the cellular response to oxidative stress through CoAlation. A combination of biochemical, biophysical, crystallographic and cell biology approaches revealed a new and, to our knowledge, unique mode of Aurora A inhibition by CoA, involving selective binding of the ADP moiety of CoA to the ATP binding pocket and covalent modification of Cys290 in the activation loop by the thiol group of the pantetheine tail. We provide evidence that covalent CoA modification (CoAlation) of Aurora A is specific, and that it can be induced by oxidative stress in human cells. Oxidising agents, such as diamide, hydrogen peroxide and menadione were found to induce Thr 288 phosphorylation and DTT-dependent dimerization of Aurora A. Moreover, microinjection of CoA into fertilized mouse embryos disrupts bipolar spindle formation and the alignment of chromosomes, consistent with Aurora A inhibition. Altogether, our data reveal CoA as a new, rather selective, inhibitor of Aurora A, which locks this kinase in an inactive state via a "dual anchor" mechanism of inhibition that might also operate in cellular response to oxidative stress. Finally and most importantly, we believe that these novel findings provide a new rationale for developing effective and irreversible inhibitors of Aurora A, and perhaps other protein kinases containing appropriately conserved Cys residues.

Overexpression of iASPP is required for autophagy in response to oxidative stress in choriocarcinoma

Background

Gestational trophoblastic disease (GTD) is a heterogeneous group of diseases developed from trophoblasts. ASPP (Ankyrin-repeat, SH3-domain and proline-rich region containing protein) family proteins, ASPP1 and ASPP2, have been reported to be dysregulated in GTD. They modulate p53 activities and are responsible for multiple cellular processes. Nevertheless, the functional role of the ASPP family inhibitory member, iASPP, is not well characterized in GTD.

Methods

To study the functional role of iASPP in GTD, trophoblastic tissues from normal placentas, hydatidiform mole (HM) and choriocarcinoma were used for immunohistochemistry, whereas siRNAs were used to manipulate iASPP expression in choriocarcinoma cell lines and study the subsequent molecular changes.

Results

We demonstrated that iASPP was overexpressed in both HM and choriocarcinoma when compared to normal placenta. Progressive increase in iASPP expression from HM to choriocarcinoma suggests that iASPP may be related to the development of trophoblastic malignancy. High iASPP expression in HM was also significantly associated with a high expression of autophagy-related protein LC3. Interestingly, iASPP silencing retarded the growth of choriocarcinoma through senescence instead of induction of apoptosis. LC3 expression decreased once iASPP was knocked down, suggesting a downregulation on autophagy. This may be due to iASPP downregulation rendered decrease in Atg5 expression and concomitantly hindered autophagy in choriocarcinoma cells. Autophagy inhibition per se had no effect on the growth of choriocarcinoma cells but increased the susceptibility of choriocarcinoma cells to oxidative stress, implying a protective role of iASPP against oxidative stress through autophagy in choriocarcinoma.

Conclusions

iASPP regulates growth and the cellular responses towards oxidative stress in choriocarcinoma cells. Its overexpression is advantageous to the pathogenesis of GTD. (266 words).

Co-Operation between Aneuploidy and Metabolic Changes in Driving Tumorigenesis

Alterations from the normal set of chromosomes are extremely common as cells progress toward tumourigenesis. Similarly, we expect to see disruption of normal cellular metabolism, particularly in the use of glucose. In this review, we discuss the connections between these two processes: how chromosomal aberrations lead to metabolic disruption, and vice versa. Both processes typically result in the production of elevated levels of reactive oxygen species, so we particularly focus on their role in mediating oncogenic changes.

Insufficiency of melatonin in follicular fluid is a reversible cause for advanced maternal age-related aneuploidy in oocytes

Age-related decline in female fertility is a common feature that occurs in the fourth decade of women as a result of a reduction in both oocyte quality and quantity [1]. However, strategies to prevent the deterioration of maternal aged oocytes and relevant mechanisms are still underexplored. Here, we find that the reduced abundance of melatonin in the follicular fluid highly correlates with the advanced maternal age-related aneuploidy. Of note, we show that exposure of oocytes from aged mice both in vitro and in vivo to exogenous melatonin not only eliminates the accumulated reactive oxygen species-induced DNA damage and apoptosis, but also suppresses the occurrence of aneuploidy caused by spindle/chromosome defect that is frequently observed in aged oocytes. Importantly, we reveal that melatonin supplementation reverses the defective phenotypes in aged oocytes through a Sirt1/Sod2-dependent mechanism. Inhibition of Sirt1 activity abolishes the melatonin-mediated improvement of aged oocyte quality. Together our findings provide evidence that supplementation of melatonin is a feasible way to protect oocytes from advanced maternal age-related meiotic defects and aneuploidy, demonstrating the potential for improving the quality of oocytes from aged women and the efficiency of assisted reproductive technology.

•

Melatonin abundance in the follicular fluid declines with age in the mouse.

•

In vitro treatment of aged oocytes with melatonin eliminates the excessive ROS and reduces the occurrence of aneuploidy.

•

In vivo administration of advanced-age mice with melatonin protects oocytes from spindle/chromosome defects and aneuploidy.

•

Melatonin supplementation reverses the meiotic defects in aged oocytes through activation of Sirt1/Sod2 pathway.

The impact of aneuploidy on cellular homeostasis

Genomic instability is a common feature of tumours that has a wide range of disruptive effects on cellular homeostasis. In this review we briefly discuss how instability comes about, then focus on the impact of gain or loss of DNA (aneuploidy) on oxidative stress. We discuss several mechanisms that lead from aneuploidy to the production of reactive oxygen species, including the effects on protein complex stoichiometry, endoplasmic reticulum stress and metabolic disruption. Each of these are involved in positive feedback loops that amplify relatively minor genetic changes into major cellular disruption or cell death, depending on the capacity of the cell to induce antioxidants or processes such as mitophagy that can moderate the disruption. Finally we examine the direct effects of reactive oxygen species on mitosis and how oxidative stress can compromise centrosome number, cytoskeletal integrity and signalling processes that are vital for mitotic fidelity.

ROS and Oxidative Stress Are Elevated in Mitosis during Asynchronous Cell Cycle Progression and Are Exacerbated by Mitotic Arrest

Although elevated levels of reactive oxygen species (ROS) have been observed in cancer cells and cancer cells aberrantly proliferate, it is not known whether the level of reactive oxygen species and the accumulation of oxidative damage to macromolecules vary across the cell cycle. Here, we measure the prevalence of reactive oxygen species and of biomolecule oxidation across the cell cycle in freely cycling cancer cells. We report that reactive oxygen species vary during the cell cycle and peak in mitosis, resulting in mitotic accumulation of oxidized protein cysteine residues. Prolonged mitotic arrest further increased the levels of ROS and the abundance of oxidatively damaged biomolecules, including cysteine-sulfenic-acid-containing proteins and 8-oxoguanine. These finding suggest that mitotic arrest agents may enhance the effects of ROS-dependent anticancer therapies.

Investigation of the effect of gestational diabetes on fetal cardiac tissue in streptozotocin ınduced in rats

PURPOSE

To investigate the cause of congenital anomalies resulted from gestational diabetes on fetal cardiac tissue in experimental animal study model.

METHODS

Totally 12 female Wistar albino rats were divided into two groups, each consisting of 6 rats. Streptozotocin (60 mg/kg) was administered intraperitoneally to the study group by dissolving in citrate solution. The rats with a blood glucose level of 200 mg/dL and above were considered to be diabetic rats. Total antioxidant status (TAS), total oxidative stress (TOS) and oxidative stress index (OSI) values were calculated in the cardiac tissues and maternal serum samples of the fetuses delivered by cesarean section after the mating process. The cardiac tissues were also subjected to histopathological examination.

RESULTS

TOS and OSI values in fetal cardiac tissues of the diabetic rats were found to be significantly higher than that of the control group (p=0.026 and p=0.005). Histopathological examination revealed that the mitotic index was lower and the cell organization was found to be damaged in the fetuses of the study group rats.

CONCLUSION

Increased levels of free oxygen radicals considered to be due to hyperglycemia may cause congenital anomalies, especially during organogenesis period, by disrupting cell homeostasis and adversely affecting mitosis.