Recycling the cell cycle: cyclins revisited

OSBPL2 compound heterozygous variants cause dyschromatosis, ichthyosis, deafness and atopic disease syndrome

PURPOSE

In this study, we identified and diagnosed a novel inherited condition called Dyschromatosis, Ichthyosis, Deafness, and Atopic Disease (DIDA) syndrome. We present a series of studies to clarify the pathogenic variants and specific mechanism.

METHODS

Exome sequencing and Sanger sequencing was conducted in affected and unaffected family members. A variety of human and cell studies were performed to explore the pathogenic process of keratosis.

RESULTS

Our finding indicated that DIDA syndrome was caused by compound heterozygous variants in the oxysterol-binding protein-related protein 2 (OSBPL2) gene. Furthermore, our findings revealed a direct interaction between OSBPL2 and Phosphoinositide phospholipase C-beta-3 (PLCB3), a key player in hyperkeratosis. OSBPL2 effectively inhibits the ubiquitylation of PLCB3, thereby stabilizing PLCB3. Conversely, OSBPL2 variants lead to enhanced ubiquitination and subsequent degradation of PLCB3, leading to epidermal hyperkeratosis, characterized by aberrant proliferation and delayed terminal differentiation of keratinocytes.

CONCLUSIONS

Our study not only unveiled the association between OSBPL2 variants and the newly identified DIDA syndrome but also shed light on the underlying mechanism.

Role of microRNA-363 during tumor progression and invasion

Recent progresses in diagnostic and therapeutic methods have significantly improved prognosis in cancer patients. However, cancer is still considered as one of the main causes of human deaths in the world. Late diagnosis in advanced tumor stages can reduce the effectiveness of treatment methods and increase mortality rate of cancer patients. Therefore, investigating the molecular mechanisms of tumor progression can help to introduce the early diagnostic markers in these patients. MicroRNA (miRNAs) has an important role in regulation of pathophysiological cellular processes. Due to their high stability in body fluids, they are always used as the non-invasive markers in cancer patients. Since, miR-363 deregulation has been reported in a wide range of cancers, we discussed the role of miR-363 during tumor progression and metastasis. It has been reported that miR-363 has mainly a tumor suppressor function through the regulation of transcription factors, apoptosis, cell cycle, and structural proteins. MiR-363 also affected the tumor progression via regulation of various signaling pathways such as WNT, MAPK, TGF-β, NOTCH, and PI3K/AKT. Therefore, miR-363 can be introduced as a probable therapeutic target as well as a non-invasive diagnostic marker in cancer patients.

Weakened APC/C activity at mitotic exit drives cancer vulnerability to KIF18A inhibition

The efficacy of current antimitotic cancer drugs is limited by toxicity in highly proliferative healthy tissues. A cancer-specific dependency on the microtubule motor protein KIF18A therefore makes it an attractive therapeutic target. Not all cancers require KIF18A, however, and the determinants underlying this distinction remain unclear. Here, we show that KIF18A inhibition drives a modest and widespread increase in spindle assembly checkpoint (SAC) signaling from kinetochores which can result in lethal mitotic delays. Whether cells arrest in mitosis depends on the robustness of the metaphase-to-anaphase transition, and cells predisposed with weak basal anaphase-promoting complex/cyclosome (APC/C) activity and/or persistent SAC signaling through metaphase are uniquely sensitive to KIF18A inhibition. KIF18A-dependent cancer cells exhibit hallmarks of this SAC:APC/C imbalance, including a long metaphase-to-anaphase transition, and slow mitosis overall. Together, our data reveal vulnerabilities in the cell division apparatus of cancer cells that can be exploited for therapeutic benefit.

Cell cycle plasticity underlies fractional resistance to palbociclib in ER+/HER2- breast tumor cells

The CDK4/6 inhibitor palbociclib blocks cell cycle progression in Estrogen receptor-positive, human epidermal growth factor 2 receptor-negative (ER+/HER2-) breast tumor cells. Despite the drug's success in improving patient outcomes, a small percentage of tumor cells continues to divide in the presence of palbociclib-a phenomenon we refer to as fractional resistance. It is critical to understand the cellular mechanisms underlying fractional resistance because the precise percentage of resistant cells in patient tissue is a strong predictor of clinical outcomes. Here, we hypothesize that fractional resistance arises from cell-to-cell differences in core cell cycle regulators that allow a subset of cells to escape CDK4/6 inhibitor therapy. We used multiplex, single-cell imaging to identify fractionally resistant cells in both cultured and primary breast tumor samples resected from patients. Resistant cells showed premature accumulation of multiple G1 regulators including E2F1, retinoblastoma protein, and CDK2, as well as enhanced sensitivity to pharmacological inhibition of CDK2 activity. Using trajectory inference approaches, we show how plasticity among cell cycle regulators gives rise to alternate cell cycle "paths" that allow individual tumor cells to escape palbociclib treatment. Understanding drivers of cell cycle plasticity, and how to eliminate resistant cell cycle paths, could lead to improved cancer therapies targeting fractionally resistant cells to improve patient outcomes.

CDK4/6 inhibitor-induced bone marrow micronuclei might be caused by cell cycle arrest during erythropoiesis

BACKGROUND

A micronucleus test is generally used to evaluate the genotoxic potential of chemicals. Exaggerated erythropoiesis, as occurs following bleeding, may induce an unexpected increase in micronucleus frequency. This false positive result would be typical in a genotoxicity study due to the enhanced progression of the cell cycle that restores decreased blood cells. The cyclin-dependent kinase (CDK) family is known to play an essential role in preventing genomic instability. Conversely, a selective CDK4/6 inhibitor PD0332991, clinically named Palbociclib, is reported to have genotoxic potential, shown by positive results in both in vitro and in vivo micronucleus studies. To clarify the mechanism by which cell cycle arrest induced by a CDK4/6 inhibitor increases micronucleus frequency, we investigated the positive results of the bone marrow micronucleus test conducted with PD0332991.

RESULTS

Rats treated with PD0332991 exhibited increased micronucleus frequency in an in vivo bone marrow micronucleus test whereas it was not increased by treatment in human lymphoblastoid TK6 cells. In addition, all other genotoxicity tests including the Ames test and the comet assay showed negative results with PD0332991. Interestingly, PD0332991 treatment led to an increase in erythrocyte size in rats and affected the size distribution of erythrocytes, including the micronucleus. The mean corpuscular volume of reticulocytes (MCVr) in the PD0332991 treatment group was significantly increased compared to that of the vehicle control (83.8 fL in the PD0332991, and 71.6 fL in the vehicle control.). Further, the average micronucleated erythrocytes (MNE) size of the PD0332991 group and vehicle control was 8.2 and 7.3 µm, respectively. In the histogram, the vehicle control showed a monomodal distribution with a peak near 7.3 µm. In contrast, the PD0332991 group showed a bimodal distribution with peaks around 7.5 and 8.5 µm. Micronucleated erythrocytes in the PD0332991 group were significantly larger than those in the vehicle control. These results suggest that the increase in micronucleus frequency induced by the CDK4/6 inhibitor is not due to genotoxicity, but is attributable to disturbance of the cell cycle, differentiation, and enucleation of erythroblasts.

CONCLUSIONS

It was suggested that the positive outcome of the in vivo bone marrow micronucleus test resulting from treatment with PD0332991 could not be attributed to its genotoxicity. Further studies to clarify the mechanism of action can contribute to the development of drug candidate compounds lacking intrinsic genotoxic effects.

Triaging between post-translational modification of cell cycle regulators and their therapeutics in neurodegenerative diseases

Neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, and Huntington's disease, present challenges in healthcare because of their complicated etiologies and absence of healing remedies. Lately, the emerging role of post-translational modifications (PTMs), in the context of cell cycle regulators, has garnered big interest as a potential avenue for therapeutic intervention. The review explores the problematic panorama of PTMs on cell cycle regulators and their implications in neurodegenerative diseases. We delve into the dynamic phosphorylation, acetylation, ubiquitination, SUMOylation, Glycation, and Neddylation that modulate the key cell cycle regulators, consisting of cyclins, cyclin-dependent kinases (CDKs), and their inhibitors. The dysregulation of these PTMs is related to aberrant cell cycle in neurons, which is one of the factors involved in neurodegenerative pathologies. Moreover, the effect of exogenous activation of CDKs and CDK inhibitors through PTMs on the signaling cascade was studied in postmitotic conditions of NDDs. Furthermore, the therapeutic implications of CDK inhibitors and associated alteration in PTMs were discussed. Lastly, we explored the putative mechanism of PTMs to restore normal neuronal function that might reverse NDDs.

Ginsenoside Rg3: A Review of its Anticancer Mechanisms and Potential Therapeutic Applications

BACKGROUND

Traditional Chinese Medicine (TCM) has a long history of treating various diseases and is increasingly being recognized as a complementary therapy for cancer. A promising natural compound extracted from the Chinese herb ginseng is ginsenoside Rg3, which has demonstrated significant anticancer effects. It has been tested in a variety of cancers and tumors and has proven to be effective in suppressing cancer.

OBJECTIVES

This work covers various aspects of the role of ginsenoside Rg3 in cancer treatment, including its biological functions, key pathways, epigenetics, and potential for combination therapies, all of which have been extensively researched and elucidated. The study aims to provide a reference for future research on ginsenoside Rg3 as an anticancer agent and a support for the potential application of ginsenoside Rg3 in cancer treatment.

KLF14 activates the JNK-signaling pathway to induce S-phase arrest in cervical cancer cells

Objective

To explore the role of Krüppel-like factor 14 (KLF14) and its underlying mechanism(s) of action in cell-cycle regulation in cervical cancer.

Methods

Lentiviral infection was used to construct KLF14, KLF14 zinc-finger structural mutations, and empty vector controls in SiHa and HeLa cervical cancer cells. The effect of KLF14 on cervical cancer cell cycle was detected by flow cytometry. The effect of KLF14 on the expression of cyclin-dependent kinase 2 (CDK2), cyclin A2 (CCNA2), and MAPK signalling pathway-related molecules was detected by fluorescence quantitative RT-PCR (qRT-PCR) and western blot. Cervical cancer cells were treated with JNK-pathway inhibitors/agonists before we assessed changes in the cell cycle and the expression of the CDK2, CCNA2, and p-JNK/JNK. Subcutaneous xenograft studies to explore the effects of KLF14 on cervical cancer cell proliferation in vivo, and western blotting was implemented to measure the expression of CCNA2, CDK2, and the activation levels of the MAPK-signaling pathway proteins in tumours.

Results

The proportion of cells in the S phase was increased in the KLF14-overexpressing group compared with the control group (P<0.001); CDK2, CCNA2, and p-JNK/JNK expression levels were elevated in the KLF14-overexpressing group relative to the control group (all P<0.05). When JNK-pathway activation was inhibited/promoted, the proportion of cells in the S phase was reduced/increased (P<0.05) and CDK2 and CCNA2 expression levels were reduced/decreased, respectively (all P<0.05). Vivo experiments revealed that KLF14 inhibited cervical cancer cell proliferation (P<0.01) and that p-JNK/JNK, CDK2, and CCNA2 expression levels were augmented in tumours in the overexpression group (P<0.01).

Conclusion

KLF14 induced S-phase arrest in cervical cancer cells and inhibited the proliferation of cervical cancer cells in vivo; the induction of S-phase arrest was related to its zinc-finger structure. KLF14 also activated the JNK pathway to induce S-phase arrest and promote the expression of CDK2 and CCNA2. In summary, KLF14 activates the JNK-signaling pathway to induce S-phase arrest in cervical cancer cells.

Interplay between zinc and cell proliferation and implications for the growth of livestock

Zinc (Zn) plays a critical role in the growth of livestock, which depends on cell proliferation. In addition to modifying the growth associated with its effects on food intake, mitogenic hormones, signal transduction and gene transcription, Zn also regulates body weight gain through mediating cell proliferation. Zn deficiency in animals leads to growth inhibition, along with an arrest of cell cycle progression at G0/G1 and S phase due to depression in the expression of cyclin D/E and DNA synthesis. Therefore, in the present study, the interplay between Zn and cell proliferation and implications for the growth of livestock were reviewed, in which Zn regulates cell proliferation in several ways, especially cell cycle progression at the G0/G1 phase DNA synthesis and mitosis. During the cell cycle, the Zn transporters and major Zn binding proteins such as metallothioneins are altered with the requirements of cellular Zn level and nuclear translocation of Zn. In addition, calcium signaling, MAPK pathway and PI3K/Akt cascades are also involved in the process of Zn-interfering cell proliferation. The evidence collected over the last decade highlights the necessity of Zn for normal cell proliferation, which suggests Zn supplementation should be considered for the growth and health of poultry.

Phytochemical screening of Prunus avium for its antioxidative and anti-mutagenic potential against DMBA-induced hepatocarcinogenesis

Scope

Prunus avium fruit is the richer source of phenolics known to exert anticancer and anti-invasive activities. The study aimed at elucidating antiproliferative and chemo-preventive potential of sweet cherries (P. avium) against the in vivo hepatocarcinoma model.

Methods and results

The quantification of ultrasound-assisted extract (UAE) of P. avium depicted anthocyanins, ferulic acid, gallic acid, quercetin, syringic acid and p- and m-coumaric acids as major phytochemicals. The hepatocarcinoma (HCC) was induced in rats through intraperitoneal administration of DMBA (20 mg/kg B.W) once a week for the period of eight weeks. The intragastric administration of P. avium UAE, as cotreatment (500 mg/Kg B.W) to treatment group, significantly (p < 0.01) attenuated the raised serum alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA), alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH) as well as total oxidative stress (TOS) and enhanced total antioxidant capacity TAOC in contrast to diseased rats. Moreover, microscopic examination of hepatic tissues confirmed the pleomorphism, nests of neoplastic hepatocytes and necrosis in HCC-bearing rats as compared to extract-fed rats, where these necrotic changes were suppressed. Besides, qRT-PCR analysis of hepatic tissues demonstrated the higher mRNA expression of CHEK1, CHEK2 and P21/CDKN1α genes, while downexpression of ATM gene in extract fed rats, further denoting the anti-mutagenic potential.

Conclusion

Consequently, the polyphenol-rich sweet cherries UAE exhibited antiproliferative and chemo-preventive potential by reducing tumor biomarkers, serum transaminases and oxidative stress, as well as enhancing antioxidant status. It further upregulated the downstream targets of ATM signaling cascade.

Functions and regulatory mechanisms of resting hematopoietic stem cells: a promising targeted therapeutic strategy

Hematopoietic stem cells (HSCs) are the common and essential precursors of all blood cells, including immune cells, and they are responsible for the lifelong maintenance and damage repair of blood tissue homeostasis. The vast majority (> 95%) of HSCs are in a resting state under physiological conditions and are only activated to play a functional role under stress conditions. This resting state affects their long-term survival and is also closely related to the lifelong maintenance of hematopoietic function; however, abnormal changes may also be an important factor leading to the decline of immune function in the body and the occurrence of diseases in various systems. While the importance of resting HSCs has attracted increasing research attention, our current understanding of this topic remains insufficient, and the direction of clinical targeted treatments is unclear. Here, we describe the functions of HSCs, analyze the regulatory mechanisms that affect their resting state, and discuss the relationship between resting HSCs and different diseases, with a view to providing guidance for the future clinical implementation of related targeted treatments.

In Vitro Pro-Apoptotic and Anti-Migratory Effects of Marantodes pumilum (syn. Labisia pumila) Extracts on Human Prostate Cancer Cell Lines: Bioguided Isolation of 5-Henicosene-1-yl-resorcinol

This study aims to evaluate the in vitro cytotoxic and anti-migratory effects of Marantodes pumilum Blume Kuntze plant extracts on prostate cancer cells, identify the active compound/s, and characterize their mechanism of action. The crude methanolic extract was partitioned into n-hexane (MPh), chloroform (MPc), and aqueous (MPa) extracts. Antiproliferative fractions (IC50 < 30 μg/mL based on SRB staining of LNCaP and PC3 cell lines) were further fractionated. Active compound/s were identified using spectroscopic methods. In vitro mechanistic studies on PC3 cells included: annexin V-FITC staining, mitochondrial membrane potential (MMP) depolarization measurements, the activity of caspases 3 and 7, nuclear DNA fragmentation, cell cycle analysis, modulation of Bax, Bcl-2, Smac/Diablo, Alox-5, VEGF-A, CXCR4, and CXCL12 mRNA gene expression via RT-PCR, 2D migration (scratch assay), and 3D invasion (Boyden chamber). MPc extract was the most active, inducing cell death (p < 0.05) via apoptosis, as evidenced by nuclear DNA fragmentation and an increase in MMP depolarization (p < 0.05) as well as the activation of caspases 3/7 (MPc p < 0.01) in both PC3 and LNCaP cell lines. In addition, MPc upregulated Bax and Smac/DIABLO, downregulated Bcl-2 (p < 0.05), and inhibited ALOX-5 mRNA gene expression (p < 0.001). MPc was not cytotoxic against normal human fibroblast cells (HDFa) at the tested concentrations. Moreover, MPc inhibited migration and invasion of PC3 cells (p < 0.01). These effects were accompanied by the downregulation of both VEGF-A and CXCL-12 gene expressions (p < 0.001). A monounsaturated 5-alkyl resorcinol was isolated as the active compound in the MPc extract and identified as 5-henicosene-1-yl-resorcinol.

The inhibition and recovery mechanisms of the diatom Phaeodactylum tricornutum in response to high light stress - A study combining physiological and transcriptional analysis

By combining physiological/biochemical and transcriptional analysis, the inhibition and recovery mechanisms of Phaeodactylum tricornutum in response to extreme high light stress (1300 μmol photons · m^-2  · s^-1 ) were elucidated. The population growth was inhibited in the first 24 h and started to recover from 48 h. At 24 h, photoinhibition was exhibited as the changes of PSII photosynthetic parameters and decrease in cellular pigments, corresponding to the downregulation of genes encoding light-harvesting complex and pigments synthesis. Changes in those photosynthetic parameters and genes were kept until 96 h, indicating that the decrease of light absorption abilities might be one strategy for photoacclimation. In the meanwhile, we observed elevated cellular ROS levels, dead cells proportions, and upregulation of genes encoding antioxidant materials and proteasome pathway at 24 h. Those stress-related parameters and genes recovered to the controls at 96 h, indicating a stable intracellular environment after photoacclimation. Finally, genes involving carbon metabolisms were upregulated from 24 to 96 h, which ensured the energy supply for keeping high base and nucleotide excision repair abilities, leading to the recovery of cell cycle progression. We concluded that P. tricornutum could overcome photoinhibition by decreasing light-harvesting abilities, enhancing carbon metabolisms, activating anti-oxidative functions, and elevating repair abilities. The parameters of light harvesting, carbon metabolisms, and repair processes were responsible for the recovery phase, which could be considered long-term adaptive strategies for diatoms under high light stress.

Cyclins and cyclin-dependent kinases: from biology to tumorigenesis and therapeutic opportunities

The discussion on cell proliferation cannot be continued without taking a look at the cell cycle regulatory machinery. Cyclin-dependent kinases (CDKs), cyclins, and CDK inhibitors (CKIs) are valuable members of this system and their equilibrium guarantees the proper progression of the cell cycle. As expected, any dysregulation in the expression or function of these components can provide a platform for excessive cell proliferation leading to tumorigenesis. The high frequency of CDK abnormalities in human cancers, together with their druggable structure has raised the possibility that perhaps designing a series of inhibitors targeting CDKs might be advantageous for restricting the survival of tumor cells; however, their application has faced a serious concern, since these groups of serine-threonine kinases possess non-canonical functions as well. In the present review, we aimed to take a look at the biology of CDKs and then magnify their contribution to tumorigenesis. Then, by arguing the bright and dark aspects of CDK inhibition in the treatment of human cancers, we intend to reach a consensus on the application of these inhibitors in clinical settings.

MicroRNA-148a Controls Epidermal and Hair Follicle Stem/Progenitor Cells by Modulating the Activities of ROCK1 and ELF5

Skin and hair development is regulated by complex programs of gene activation and silencing and microRNA-dependent modulation of gene expression to maintain normal skin and hair follicle development, homeostasis, and cycling. In this study, we show that miR-148a, through its gene targets, plays an important role in regulating skin homeostasis and hair follicle cycling. RNA and protein analysis of miR-148a and its gene targets were analyzed using a combination of in vitro and in vivo experiments. We show that the expression of miR-148a markedly increases during telogen (bulge and hair germ stem cell compartments). Administration of antisense miR-148a inhibitor into mouse skin during the telogen phases of the postnatal hair cycle results in accelerated anagen development and altered stem cell activity in the skin. We also show that miR-148a can regulate colony-forming abilities of hair follicle bulge stem cells as well as control keratinocyte proliferation/differentiation processes. RNA and protein analysis revealed that miR-148a may control these processes by regulating the expression of Rock1 and Elf5 in vitro and in vivo. These data provide an important foundation for further analyses of miR-148a as a crucial regulator of these genes target in the skin and hair follicles and its importance in maintaining stem/progenitor cell functions during normal tissue homeostasis and regeneration.

Inferring cell cycle phases from a partially temporal network of protein interactions

The temporal organization of biological systems is key for understanding them, but current methods for identifying this organization are often ad hoc and require prior knowledge. We present Phasik, a method that automatically identifies this multiscale organization by combining time series data (protein or gene expression) and interaction data (protein-protein interaction network). Phasik builds a (partially) temporal network and uses clustering to infer temporal phases. We demonstrate the method's effectiveness by recovering well-known phases and sub-phases of the cell cycle of budding yeast and phase arrests of mutants. We also show its general applicability using temporal gene expression data from circadian rhythms in wild-type and mutant mouse models. We systematically test Phasik's robustness and investigate the effect of having only partial temporal information. As time-resolved, multiomics datasets become more common, this method will allow the study of temporal regulation in lesser-known biological contexts, such as development, metabolism, and disease.

Medicinal chemistry perspective of pyrido[2,3-d]pyrimidines as anticancer agents

Cancer is a major cause of deaths across the globe due to chemoresistance and lack of selective chemotherapy. Pyrido[2,3-d]pyrimidine is an emerging scaffold in medicinal chemistry having a broad spectrum of activities, including antitumor, antibacterial, CNS depressive, anticonvulsant, and antipyretic activities. In this study, we have covered different cancer targets, including tyrosine kinase, extracellular regulated protein kinases - ABL kinase, phosphatidylinositol-3 kinase, mammalian target of rapamycin, p38 mitogen-activated protein kinases, BCR-ABL, dihydrofolate reductase, cyclin-dependent kinase, phosphodiesterase, KRAS and fibroblast growth factor receptors, their signaling pathways, mechanism of action and structure-activity relationship of pyrido[2,3-d]pyrimidine derivatives as inhibitors of the above-mentioned targets. This review will represent the complete medicinal and pharmacological profile of pyrido[2,3-d]pyrimidines as anticancer agents, and will help scientists to design new selective, effective and safe anticancer agents.

Maternal mRNA deadenylation and allocation via Rbm14 condensates facilitate vertebrate blastula development

Early embryonic development depends on proper utilization and clearance of maternal transcriptomes. How these processes are spatiotemporally regulated remains unclear. Here we show that nuclear RNA-binding protein Rbm14 and maternal mRNAs co-phase separate into cytoplasmic condensates to facilitate vertebrate blastula-to-gastrula development. In zebrafish, Rbm14 condensates were highly abundant in blastomeres and markedly reduced after prominent activation of zygotic transcription. They concentrated at spindle poles by associating with centrosomal γ-tubulin puncta and displayed mainly asymmetric divisions with a global symmetry across embryonic midline in 8- and 16-cell embryos. Their formation was dose-dependently stimulated by m6 A, but repressed by m5 C modification of the maternal mRNA. Furthermore, deadenylase Parn co-phase separated with these condensates, and this was required for deadenylation of the mRNAs in early blastomeres. Depletion of Rbm14 impaired embryonic cell differentiations and full activations of the zygotic genome in both zebrafish and mouse and resulted in developmental arrest at the blastula stage. Our results suggest that cytoplasmic Rbm14 condensate formation regulates early embryogenesis by facilitating deadenylation, protection, and mitotic allocation of m6 A-modified maternal mRNAs, and by releasing the poly(A)-less transcripts upon regulated disassembly to allow their re-polyadenylation and translation or clearance.

HN1 Is Enriched in the S-Phase, Phosphorylated in Mitosis, and Contributes to Cyclin B1 Degradation in Prostate Cancer Cells

HN1 has previously been shown as overexpressed in various cancers. In Prostate cancer, it regulates AR signaling and centrosome-related functions. Previously, in two different studies, HN1 expression has been observed as inversely correlated with Cyclin B1. However, HN1 interacting partners and the role of HN1 interactions in cell cycle pathways have not been completely elucidated. Therefore, we used Prostate cancer cell lines again and utilized both transient and stable inducible overexpression systems to delineate the role of HN1 in the cell cycle. HN1 characterization was performed using treatments of kinase inhibitors, western blotting, flow cytometry, immunofluorescence, cellular fractionation, and immunoprecipitation approaches. Our findings suggest that HN1 overexpression before mitosis (post-G2), using both transient and stable expression systems, leads to S-phase accumulation and causes early mitotic exit after post-G2 overexpression. Mechanistically, HN1 interacted with Cyclin B1 and increased its degradation via ubiquitination through stabilized Cdh1, which is a co-factor of the APC/C complex. Stably HN1-expressing cells exhibited a reduced Cdt1 loading onto chromatin, demonstrating an exit from a G1 to S phenotype. We found HN1 and Cdh1 interaction as a new regulator of the Cyclin B1/CDK1 axis in mitotic regulation which can be explored further to dissect the roles of HN1 in the cell cycle.

Cell cycle related long non-coding RNAs as the critical regulators of breast cancer progression and metastasis

Cell cycle is one of the main cellular mechanisms involved in tumor progression. Almost all of the active molecular pathways in tumor cells directly or indirectly target the cell cycle progression. Therefore, it is necessary to assess the molecular mechanisms involved in cell cycle regulation in tumor cells. Since, early diagnosis has pivotal role in better cancer management and treatment, it is required to introduce the non-invasive diagnostic markers. Long non-coding RNAs (LncRNAs) have higher stability in body fluids in comparison with mRNAs. Therefore, they can be used as efficient non-invasive markers for the early detection of breast cancer (BCa). In the present review we have summarized all of the reported lncRNAs involved in cell cycle regulation in BCa. It has been reported that lncRNAs mainly affect the cell cycle in G1/S transition through the CCND1/CDK4-6 complex. Present review paves the way of introducing the cell cycle related lncRNAs as efficient markers for the early detection of BCa.

Keeping development on time: Insights into post-transcriptional mechanisms driving oscillatory gene expression during vertebrate segmentation

Biological time keeping, or the duration and tempo at which biological processes occur, is a phenomenon that drives dynamic molecular and morphological changes that manifest throughout many facets of life. In some cases, the molecular mechanisms regulating the timing of biological transitions are driven by genetic oscillations, or periodic increases and decreases in expression of genes described collectively as a "molecular clock." In vertebrate animals, molecular clocks play a crucial role in fundamental patterning and cell differentiation processes throughout development. For example, during early vertebrate embryogenesis, the segmentation clock regulates the patterning of the embryonic mesoderm into segmented blocks of tissue called somites, which later give rise to axial skeletal muscle and vertebrae. Segmentation clock oscillations are characterized by rapid cycles of mRNA and protein expression. For segmentation clock oscillations to persist, the transcript and protein molecules of clock genes must be short-lived. Faithful, rhythmic, genetic oscillations are sustained by precise regulation at many levels, including post-transcriptional regulation, and such mechanisms are essential for proper vertebrate development. This article is categorized under: RNA Export and Localization > RNA Localization RNA Turnover and Surveillance > Regulation of RNA Stability Translation > Regulation.

Chemopreventive and therapeutic properties of anthocyanins in breast cancer: A comprehensive review

Anthocyanins have received the attention of the scientific community because of their antioxidant, antimetastatic, and cancer-inhibitory properties. The aim of this review is to comprehensively summarize the possible mechanisms by which anthocyanins exhibit anticarcinogenic properties in breast cancer (BC) cell lines and animal models. Anthocyanins inhibit proinflammatory, signal transducer and activator of transcription 3, and nuclear factor kappa-light-chain-enhancer of activated B cell pathways and increase the activities of detoxification enzymes. In addition, downregulation of metalloproteinases by anthocyanins inhibits tumor invasion and metastatic processes in experimental systems. Anthocyanins mediate anticancer and angiogenic effects by modifying multiple receptor families. Furthermore, inhibition of cell-cycle upstream polo-like kinase signaling, the chromosomal replication checkpoint, and ataxia telangiectasia mutated signaling may contribute to the anticarcinogenic effects of anthocyanins. Finally, anthocyanins induce mitochondrial-mediated apoptosis and downregulate the phosphatidylinositol-3-kinase/AKT/mTOR pathway. In conclusion, anthocyanins have been shown to exert potential antitumor effects against breast carcinogenesis in vitro and in vivo, providing insights into the use of anthocyanins as a natural chemopreventive intervention in BC.

Genome-Wide Identification, Expression Profiling, and Characterization of Cyclin-like Genes Reveal Their Role in the Fertility of the Diamondback Moth

Simple Summary

Cyclin genes are known as cell cycle regulators and play a significant role in the fertility of different organisms, including mice and insects. Until now, no study has been performed on the complete identification of the cyclin genes in insects. Here, we identified 21 cyclin genes in the diamondback moth (DBM) genome through a comprehensive genome-wide analysis and evaluated the gene structure, genomic location, and evolutionary relationship. Cis-regulatory elements and potential miRNA targeting the cyclin genes were also assessed. By analyzing the transcriptomic and RT-qPCR based expression profiling at different stages and tissues, we found that the majority of the cyclin genes were significantly expressed in the reproductive tissues. Moreover, RNAi-mediated characterization of PxCyc B1 showed its role in female fertility. The current study provides a basis for further evaluation of the cyclin genes, which may be used as a potential target for pest management programs.

Abstract

Cyclin-like genes are primarily considered as cell cycle regulators and have shown to be crucial for insect growth, development, reproduction, and fertility. However, no research has been performed on the cyclin-like genes in the diamondback moth (Plutella xylostella). Here, we identified the 21 cyclin genes in the genome of P. xylostella and clustered them into four groups. Most cyclin genes showed a well-maintained gene structure and motif distribution within the same group. The putative promoter regions of cyclin genes contained several transcription binding factors related to reproduction, along with growth and development. Furthermore, 16 miRNAs were identified targeting the 13 cyclin genes. Transcriptome and quantitative real-time PCR (qRT-PCR)-based expression profiling of cyclin-like genes at different stages and tissues were evaluated, revealing that 16 out of 21 cyclin genes were highly expressed in reproductive tissues of adult females and males. The Cyclin B1 gene (PxCyc B1) was only expressed in the ovary of the adult female and selected for the subsequent analysis. RNAi-mediated suppression of PxCyc B1 interrupted the external genitalia and length of the ovariole of female adults. Furthermore, the egg-laying capacity and hatching rate were also significantly decreased by suppressing the PxCyc B1, indicating the importance of cyclin genes in the reproduction and fertility of P. xylostella. The current study explained the detailed genome-wide analysis of cyclin-like genes in P. xylostella, which provided a basis for subsequent research to assess the roles of cyclin genes in reproduction, and the cyclin gene may be considered an effective target site to control this pest.

Deoxypodophyllotoxin Induces ROS-Mediated Apoptosis by Modulating the PI3K/AKT and p38 MAPK-Dependent Signaling in Oral Squamous Cell Carcinoma

Deoxypodophyllotoxin (DPT), a naturally occurring flavonolignan, possesses several pharmacological properties, including anticancer property. However, the mechanisms underlying DPT mode of action in oral squamous cell carcinoma (OSCC) remain unknown. This study aimed to investigate the anticancer effects of DPT on OSCC and the underlying mechanisms. Results of the MTT assay revealed that DPT significantly reduced the cell viability in a time- and dose-dependent manner. Flow cytometry analysis revealed that DPT induces apoptosis in OSCC cells in a dose-dependent manner. Moreover, DPT enhanced the production of mitochondrial reactive oxygen species (ROS) in OSCC cells. Mechanistically, DPT induced apoptosis in OSCC cells by suppressing the PI3K/AKT signaling pathway while activating the p38 MAPK signaling to regulate the expression of apoptotic proteins. Treatment with SC79, an AKT activator, reversed the effects of DPT on AKT signaling in OSCC cells. Taken together, these results provide the basis for the use of DPT in combination with conventional chemotherapy for the treatment of oral cancer.

Heparanase modulates the prognosis and development of BRAF V600E-mutant colorectal cancer by regulating AKT/p27Kip1/Cyclin E2 pathway

BRAF V600E-mutant colorectal cancer (CRC) is a rare subtype of colorectal cancer with poor prognosis. Compelling evidence indicates that the heparanase (HPSE) gene has multiple functions in cancer, however, its role in BRAF V600E-mutant CRC remains elusive. Differentially expressed genes between BRAF V600E-mutant and wild-type patients were explored by analyzing public data from The Cancer Genome Atlas and the Gene Expression Omnibus. Clinical samples of 172 patients with BRAF V600E-mutant CRC diagnosed at Zhongshan Hospital Fudan University were collected. Overall survival was analyzed using Kaplan-Meier curves and Cox regression models. Cell models and xenografts were utilized to investigate the effect of HPSE on tumor proliferation. HPSE was significantly highly expressed in the BRAF V600E-mutant group. High HPSE expression level was independently associated with inferior survival in the BRAF V600E-mutant cohort. HPSE knockdown impeded tumor proliferation of BRAF V600E-mutant CRC cells in vitro and in vivo. Mechanistically, HPSE silencing arrested cell cycle in G0/G1 phase by downregulating Cyclin E2 expression via the AKT/p27Kip1 pathway. These findings support a role for HPSE in promoting BRAF V600E-mutant CRC progression, which suggests it holds great promise as a prognostic biomarker and a potential therapeutic target for the aggressive CRC subtype.

Objective assessment of adrenocortical carcinoma driver genes and their correlation with tumor pyruvate kinase M2

Glandular cancers have a significant share of the total cancer patients all over the world. In the case of adrenocortical carcinomas (ACCs), although the benign form is more frequent and common, the malignant form provides a very less percentage of patients with five or more than five years of survival rate. There are gene alterations that are involved as a crucial factor behind the occurrence of ACCs. Out of these, the most prominent genetic alterations (PRKAR-1A, CTNNB1, ZNRF3, TP53, CCNE1 and TERF2 genes) are linked with a glycolytic enzyme pyruvate kinase M2 (PKM2), which converts phosphoenolpyruvate (PEP) to pyruvate in the glycolytic pathway. The involvementof PKM2 renders a cumulative effect through different pathways that may result in the onset of ACCs. Thus, this review aims to establish a link between ACCs, alterations of specific genes and PKM2.

PPP4C facilitates homologous recombination DNA repair by dephosphorylating PLK1 during early embryo development

Mammalian early embryo cells have complex DNA repair mechanisms to maintain genomic integrity, and homologous recombination (HR) plays the main role in response to double-strand DNA breaks (DSBs) in these cells. Polo-like kinase 1 (PLK1) participates in the HR process and its overexpression has been shown to occur in a variety of human cancers. Nevertheless, the regulatory mechanism of PLK1 remains poorly understood, especially during the S and G2 phase. Here, we show that protein phosphatase 4 catalytic subunit (PPP4C) deletion causes severe female subfertility due to accumulation of DNA damage in oocytes and early embryos. PPP4C dephosphorylated PLK1 at the S137 site, negatively regulating its activity in the DSB response in early embryonic cells. Depletion of PPP4C induced sustained activity of PLK1 when cells exhibited DNA lesions that inhibited CHK2 and upregulated the activation of CDK1, resulting in inefficient loading of the essential HR factor RAD51. On the other hand, when inhibiting PLK1 in the S phase, DNA end resection was restricted. These results demonstrate that PPP4C orchestrates the switch between high-PLK1 and low-PLK1 periods, which couple the checkpoint to HR.

Regulated interaction of ID2 with the anaphase-promoting complex links progression through mitosis with reactivation of cell-type-specific transcription

Tissue-specific transcriptional activity is silenced in mitotic cells but it remains unclear whether the mitotic regulatory machinery interacts with tissue-specific transcriptional programs. We show that such cross-talk involves the controlled interaction between core subunits of the anaphase-promoting complex (APC) and the ID2 substrate. The N-terminus of ID2 is independently and structurally compatible with a pocket composed of core APC/C subunits that may optimally orient ID2 onto the APCCDH1 complex. Phosphorylation of serine-5 by CDK1 prevented the association of ID2 with core APC, impaired ubiquitylation and stabilized ID2 protein at the mitosis-G1 transition leading to inhibition of basic Helix-Loop-Helix (bHLH)-mediated transcription. The serine-5 phospho-mimetic mutant of ID2 that inefficiently bound core APC remained stable during mitosis, delayed exit from mitosis and reloading of bHLH transcription factors on chromatin. It also locked cells into a "mitotic stem cell" transcriptional state resembling the pluripotent program of embryonic stem cells. The substrates of APCCDH1 SKP2 and Cyclin B1 share with ID2 the phosphorylation-dependent, D-box-independent interaction with core APC. These results reveal a new layer of control of the mechanism by which substrates are recognized by APC.

Effect of Sperm 26S Proteasome on Embryo Formation and Development in In Vitro Fertilization

The aim of this study was to evaluate the effects of sperm proteasome activity on fertilization outcome and embryo development after IVF. Following density gradient centrifugation for IVF purpose, the spermatozoa of 84 infertile patients with tubal factor were evaluated by luciferase enzymatic activity to assess the proteasome quantity. The mean age of patients was 33.8 years, and the mean concentration of human spermatozoa 26S proteasome was 674.53 ng/ml. After IVF, the embryos were scored for morphology. The spermatozoa proteasome activity was both positively correlated with fertilization rate in vitro (P = 0.0003) and 2PN rate (P = 0.0007). Compared to low fertilization rate group, the high fertilization rate group showed a significantly higher level of spermatozoa proteasome activity (P = 0.002). In conclusion, sperm proteasome activity provides additional data on sperm functional capacity in terms of fertilization during IVF.

2-Methoxy-5((3,4,5-trimethosyphenyl) seleninyl) phenol causes G2/M cell cycle arrest and apoptosis in NSCLC cells through mitochondrial apoptotic pathway and MDM2 inhibition

Nonsmall cell lung cancer (NSCLC) is one of the most common malignancies and needs novel and effective chemotherapy. In this study, our purpose is to explore the anticancer effects of 2-methoxy-5((3,4,5-trimethosyphenyl) seleninyl) phenol (SQ) on human NSCLC (A549 and H460) cells. We found that SQ suppressed the proliferation of NSCLC cells in time- and dose-dependent manners, and blocked the cells at G2/M phase, which was relevant to microtubule depolymerization. Additionally, SQ induced A549 and H460 cell apoptosis by activating the mitochondrial apoptotic pathway. Further, we demonstrated that SQ enhanced the generation of reactive oxygen species (ROS), and pretreatment with N-acetyl- L-cysteine (NAC) attenuated SQ-induced cell apoptosis. Meanwhile, SQ mediated-ROS generation caused DNA damage in A549 and H460 cells. Our data also revealed that SQ-induced apoptosis was correlated with the inhibition of mouse double minute 2 (MDM2) in A549 and H460 cells. In summary, our research indicates that the novel compound SQ has great potential for therapeutic treatment of NSCLC in future.

multiFLEX-LF: A Computational Approach to Quantify the Modification Stoichiometries in Label-Free Proteomics Data Sets

In liquid-chromatography-tandem-mass-spectrometry-based proteomics, information about the presence and stoichiometry of protein modifications is not readily available. To overcome this problem, we developed multiFLEX-LF, a computational tool that builds upon FLEXIQuant, which detects modified peptide precursors and quantifies their modification extent by monitoring the differences between observed and expected intensities of the unmodified precursors. multiFLEX-LF relies on robust linear regression to calculate the modification extent of a given precursor relative to a within-study reference. multiFLEX-LF can analyze entire label-free discovery proteomics data sets in a precursor-centric manner without preselecting a protein of interest. To analyze modification dynamics and coregulated modifications, we hierarchically clustered the precursors of all proteins based on their computed relative modification scores. We applied multiFLEX-LF to a data-independent-acquisition-based data set acquired using the anaphase-promoting complex/cyclosome (APC/C) isolated at various time points during mitosis. The clustering of the precursors allows for identifying varying modification dynamics and ordering the modification events. Overall, multiFLEX-LF enables the fast identification of potentially differentially modified peptide precursors and the quantification of their differential modification extent in large data sets using a personal computer. Additionally, multiFLEX-LF can drive the large-scale investigation of the modification dynamics of peptide precursors in time-series and case-control studies. multiFLEX-LF is available at https://gitlab.com/SteenOmicsLab/multiflex-lf.

MiR-597-5p suppresses the progression of hepatocellular carcinoma via targeting transcriptional enhancer associate domain transcription factor 1 (TEAD1)

Hepatocellular carcinoma (HCC) is the most common primary liver cancer with high incidence and mortality. MiR-597-5p is downregulated in tumor tissues of HCC compared with non-tumor tissues. However, its role in HCC is still unknown. This study aims to assess the function of miR-597-5p in HCC development and investigate the underlying mechanism. To perform gain- and loss-of-function studies, SK-HEP-1 cells and Huh-7 cells were transfected with miR-597-5p mimics and inhibitor, respectively. MiR-597-5p markedly reduced the cell viability and the expression of Ki-67 in HCC cells. MiR-597-5p also repressed the cell cycle progression of HCC cells and the protein levels of cyclin D1 and CDK2. Moreover, miR597-5p inhibited the migration and invasion of HCC cells and decreased MMP2 and MMP9 levels. Transcriptional enhancer associate domain transcription factor 1 (TEAD1) was identified as a target of miR-597-5p by luciferase reporter assay. TEAD1 and its downstream target genes, CTGF and CYR61, were downregulated by miR-597-5p in HCC cells. Furthermore, miR-597-5p was demonstrated to function in HCC progression by targeting TEAD1 via TEAD1 expression gain and loss. Our study demonstrates that miR-597-5p represses the proliferation, migration, and invasion of HCC cells through targeting TEAD1, which provides a therapeutic target for HCC treatment.

Circular RNAs in cell cycle regulation: Mechanisms to clinical significance

Circular RNAs (circRNAs), a type of non‐coding RNA, are single‐stranded circularized molecules characterized by high abundance, evolutionary conservation and cell development‐ and tissue‐specific expression. A large body of studies has found that circRNAs exert a wide variety of functions in diverse biological processes, including cell cycle. The cell cycle is controlled by the coordinated activation and deactivation of cell cycle regulators. CircRNAs exert mutifunctional roles by regulating gene expression via various mechanisms. However, the functional relevance of circRNAs and cell cycle regulation largely remains to be elucidated. Herein, we briefly describe the biogenesis and mechanistic models of circRNAs and summarize their functions and mechanisms in the regulation of critical cell cycle modulators, including cyclins, cyclin‐dependent kinases and cyclin‐dependent kinase inhibitors. Moreover, we highlight the participation of circRNAs in cell cycle‐related signalling pathways and the clinical value of circRNAs as promising biomarkers or therapeutic targets in diseases related to cell cycle disorder.

Aromatic hydrocarbon receptors in mitochondrial biogenesis and function

Mitochondria are ubiquitous membrane-bound organelles that not only play a key role in maintaining cellular energy homeostasis and metabolism but also in signaling and apoptosis. Aryl hydrocarbons receptors (AhRs) are ligand-activated transcription factors that recognize a wide variety of xenobiotics, including polyaromatic hydrocarbons and dioxins, and activate diverse detoxification pathways. These receptors are also activated by natural dietary compounds and endogenous metabolites. In addition, AhRs can modulate the expression of a diverse array of genes related to mitochondrial biogenesis and function. The aim of the present review is to analyze scientific data available on the AhR signaling pathway and its interaction with the intracellular signaling pathways involved in mitochondrial functions, especially those related to cell cycle progression and apoptosis. Various evidence have reported the crosstalk between the AhR signaling pathway and the nuclear factor κB (NF-κB), tyrosine kinase receptor signaling and mitogen-activated protein kinases (MAPKs). The AhR signaling pathway seems to promote cell cycle progression in the absence of exogenous ligands, whereas the presence of exogenous ligands induces cell cycle arrest. However, its effects on apoptosis are controversial since activation or overexpression of AhR has been observed to induce or inhibit apoptosis depending on the cell type. Regarding the mitochondria, although activation by endogenous ligands is related to mitochondrial dysfunction, the effects of endogenous ligands are not well understood but point towards antiapoptotic effects and inducers of mitochondrial biogenesis.

Discovery and Validation of a Compound to Target Ewing's Sarcoma

Ewing’s sarcoma, characterized by pathognomonic t (11; 22) (q24; q12) and related chromosomal ETS family translocations, is a rare aggressive cancer of bone and soft tissue. Current protocols that include cytotoxic chemotherapeutic agents effectively treat localized disease; however, these aggressive therapies may result in treatment-related morbidities including second-site cancers in survivors. Moreover, the five-year survival rate in patients with relapsed, recurrent, or metastatic disease is less than 30%, despite intensive therapy with these cytotoxic agents. By using high-throughput phenotypic screening of small molecule libraries, we identified a previously uncharacterized compound (ML111) that inhibited in vitro proliferation of six established Ewing’s sarcoma cell lines with nanomolar potency. Proteomic studies show that ML111 treatment induced prometaphase arrest followed by rapid caspase-dependent apoptotic cell death in Ewing’s sarcoma cell lines. ML111, delivered via methoxypoly(ethylene glycol)-polycaprolactone copolymer nanoparticles, induced dose-dependent inhibition of Ewing’s sarcoma tumor growth in a murine xenograft model and invoked prometaphase arrest in vivo, consistent with in vitro data. These results suggest that ML111 represents a promising new drug lead for further preclinical studies and is a potential clinical development for the treatment of Ewing’s sarcoma.

Influence of Ce3+ Substitution on Antimicrobial and Antibiofilm Properties of ZnCexFe2-xO4 Nanoparticles (X = 0.0, 0.02, 0.04, 0.06, and 0.08) Conjugated with Ebselen and Its Role Subsidised with γ-Radiation in Mitigating Human TNBC and Colorectal Adenocarcinoma Proliferation In Vitro

Cancers are a major challenge to health worldwide. Spinel ferrites have attracted attention due to their broad theranostic applications. This study aimed at investigating the antimicrobial, antibiofilm, and anticancer activities of ebselen (Eb) and cerium-nanoparticles (Ce-NPs) in the form of ZnCexFe2-XO4 on human breast and colon cancer cell lines. Bioassays of the cytotoxic concentrations of Eb and ZnCexFe2-XO4, oxidative stress and inflammatory milieu, autophagy, apoptosis, related signalling effectors, the distribution of cells through the cell-cycle phases, and the percentage of cells with apoptosis were evaluated in cancer cell lines. Additionally, the antimicrobial and antibiofilm potential have been investigated against different pathogenic microbes. The ZOI, and MIC results indicated that ZnCexFe2-XO4; X = 0.06 specimen reduced the activity of a wide range of bacteria and unicellular fungi at low concentration including P. aeruginosa (9.5 mm; 6.250 µg/mL), S. aureus (13.2 mm; 0.390 µg/mL), and Candida albicans (13.5 mm; 0.195 µg/mL). Reaction mechanism determination indicated that after ZnCexFe2-xO4; X = 0.06 treatment, morphological differences in S.aureus were apparent with complete lysis of bacterial cells, a concomitant decrease in the viable number, and the growth of biofilm was inhibited. The combination of Eb with ZFO or ZnCexFe2-XO4 with γ-radiation exposure showed marked anti-proliferative efficacy in both cell lines, through modulating the oxidant/antioxidant machinery imbalance, restoring the fine-tuning of redox status, and promoting an anti-inflammatory milieu to prevent cancer progression, which may be a valuable therapeutic approach to cancer therapy and as a promising antimicrobial agent to reduce the pathogenic potential of the invading microbes.

Antitumorigenic effect of insect-derived peptide poecilocorisin-1 in human skin cancer cells through regulation of Sp1 transcription factor

Malignant melanoma is highly resistant to conventional treatments and is one of the most aggressive types of skin cancers. Conventional cancer treatments are limited due to drug resistance, tumor selectivity, and solubility. Therefore, new treatments with fewer side effects and excellent effects should be developed. In previous studies, we have analyzed antimicrobial peptides (AMPs), which showed antibacterial and anti-inflammatory effects in insects, and some AMPs also exhibited anticancer efficacy. Anticancer peptides (ACPs) are known to have fewer side effects and high anticancer efficacy. In this study, the insect-derived peptide poecilocorisin-1 (PCC-1) did not induce toxicity in the human epithelial cell line HaCaT, but its potential as an anticancer agent was confirmed through specific effects of antiproliferation, apoptosis, and cell cycle arrest in two melanoma cell lines, SK-MEL-28 and G361. Additionally, we discovered a novel anticancer mechanism of insect-derived peptides in melanoma through the regulation of transcription factor Sp1 protein, which is overexpressed in cancer, apoptosis, and cell cycle-related proteins. Taken together, this study aims to clarify the anticancer efficacy and safety of insect-derived peptides and to present their potential as future therapeutic agents.

Rapid initiation of cell cycle reentry processes protects neurons from amyloid-β toxicity

Neurons are postmitotic cells. Reactivation of the cell cycle by neurons has been reported in Alzheimer's disease (AD) brains and models. This gave rise to the hypothesis that reentering the cell cycle renders neurons vulnerable and thus contributes to AD pathogenesis. Here, we use the fluorescent ubiquitination-based cell cycle indicator (FUCCI) technology to monitor the cell cycle in live neurons. We found transient, self-limited cell cycle reentry activity in naive neurons, suggesting that their postmitotic state is a dynamic process. Furthermore, we observed a diverse response to oligomeric amyloid-β (oAβ) challenge; neurons without cell cycle reentry activity would undergo cell death without activating the FUCCI reporter, while neurons undergoing cell cycle reentry activity at the time of the oAβ challenge could maintain and increase FUCCI reporter signal and evade cell death. Accordingly, we observed marked neuronal FUCCI positivity in the brains of human mutant Aβ precursor protein transgenic (APP23) mice together with increased neuronal expression of the endogenous cell cycle control protein geminin in the brains of 3-mo-old APP23 mice and human AD brains. Taken together, our data challenge the current view on cell cycle in neurons and AD, suggesting that pathways active during early cell cycle reentry in neurons protect from Aβ toxicity.

d-Serine Mediates Cellular Proliferation for Kidney Remodeling

Background

d-serine, a long-term undetected enantiomer of serine, is a biomarker that reflects kidney function and disease activity. The physiologic functions of d-serine are unclear.

Methods

The dynamics of d-serine were assessed by measuring d-serine in human samples of living kidney donors using two-dimensional high-performance liquid chromatography, and by autoradiographic studies in mice. The effects of d-serine on the kidney were examined by gene expression profiling and metabolic studies using unilateral nephrectomy mice, and genetically modified cells.

Results

Unilateral nephrectomy in human living kidney donors decreases urinary excretion and thus increases the blood level of d-serine. d-serine is quickly and dominantly distributed to the kidney on injection in mice, suggesting the kidney is a main target organ. Treatment of d-serine at a low dose promotes the enlargement of remnant kidney in mouse model. Mechanistically, d-serine activates the cell cycle for tissue remodeling through an mTOR-related pathway.

Conclusions

d-serine is a physiologic molecule that promotes kidney remodeling. Besides its function as a biomarker, d-serine has a physiologic activity that influences kidney function.

Are There Biomimetic Lessons from Genetic Regulatory Networks for Developing a Lunar Industrial Ecology?

We examine the prospect for employing a bio-inspired architecture for a lunar industrial ecology based on genetic regulatory networks. The lunar industrial ecology resembles a metabolic system in that it comprises multiple chemical processes interlinked through waste recycling. Initially, we examine lessons from factory organisation which have evolved into a bio-inspired concept, the reconfigurable holonic architecture. We then examine genetic regulatory networks and their application in the biological cell cycle. There are numerous subtleties that would be challenging to implement in a lunar industrial ecology but much of the essence of biological circuitry (as implemented in synthetic biology, for example) is captured by traditional electrical engineering design with emphasis on feedforward and feedback loops to implement robustness.

Antiproliferative and Oxidative Damage Protection Activities of Endophytic Fungi Aspergillus fumigatus and Chaetomium globosum from Moringa oleifera Lam

The current study was conducted to evaluate the antiproliferative and oxidative damage protection potential of endophytic fungi Aspergillus fumigatus and Chaetomium globosum isolated from Moringa oleifera. The chloroformic extract (CE) of both the fungi showed dose dependent antiproliferative activity against human prostate adenocarcinoma (PC-3) cell line with (IC₅₀) value of 0.055 mg/ml and 0.008 mg/ml, respectively. Further, CE of both the fungi was studied for their ability to induce apoptosis in PC-3 cell line. Various deformities in the cancerous cells treated with CE of both the fungi have been observed by confocal microscopy which indicates the cell death by apoptosis. Further apoptosis inducing ability of CE of both the fungi was observed using various flow cytometric studies. The chloroformic extract of both the fungi showed slight increase in the level of reactive oxygen species to induce apoptosis. It also showed arrest of cancerous cells at G0/G1 phase of cell cycle to induce apoptosis. The externalization of phosphatidylserine (PS) to induce apoptosis was also observed when analysed using Annexin V-FITC/PI double staining assay where the CE of A. fumigatus and C. globosum showed the total apoptosis of 94.2% and 90.3%, respectively, at the highest tested concentration of GI₇₀. The CE of both the fungi further showed the protective behaviour for plasmid DNA pBR322, when tested for their effect against the oxidative stress caused by the Fenton's reagent. Thus, the studies demonstrated a good antiproliferative and oxidative damage protection potential of the endophytic fungi.

Cell cycle control during early embryogenesis

Understanding the mechanisms of embryonic cell cycles is a central goal of developmental biology, as the regulation of the cell cycle must be closely coordinated with other events during early embryogenesis. Quantitative imaging approaches have recently begun to reveal how the cell cycle oscillator is controlled in space and time, and how it is integrated with mechanical signals to drive morphogenesis. Here, we discuss how the Drosophila embryo has served as an excellent model for addressing the molecular and physical mechanisms of embryonic cell cycles, with comparisons to other model systems to highlight conserved and species-specific mechanisms. We describe how the rapid cleavage divisions characteristic of most metazoan embryos require chemical waves and cytoplasmic flows to coordinate morphogenesis across the large expanse of the embryo. We also outline how, in the late cleavage divisions, the cell cycle is inter-regulated with the activation of gene expression to ensure a reliable maternal-to-zygotic transition. Finally, we discuss how precise transcriptional regulation of the timing of mitosis ensures that tissue morphogenesis and cell proliferation are tightly controlled during gastrulation.

The Influence of Cell Cycle Regulation on Chemotherapy

Cell cycle regulation is orchestrated by a complex network of interactions between proteins, enzymes, cytokines, and cell cycle signaling pathways, and is vital for cell proliferation, growth, and repair. The occurrence, development, and metastasis of tumors are closely related to the cell cycle. Cell cycle regulation can be synergistic with chemotherapy in two aspects: inhibition or promotion. The sensitivity of tumor cells to chemotherapeutic drugs can be improved with the cooperation of cell cycle regulation strategies. This review presented the mechanism of the commonly used chemotherapeutic drugs and the effect of the cell cycle on tumorigenesis and development, and the interaction between chemotherapy and cell cycle regulation in cancer treatment was briefly introduced. The current collaborative strategies of chemotherapy and cell cycle regulation are discussed in detail. Finally, we outline the challenges and perspectives about the improvement of combination strategies for cancer therapy.

lncRNA MALAT1 participates in metformin inhibiting the proliferation of breast cancer cell

In recent years, the repurposing of conventional and chemotherapeutic drugs is recognized as an alternative strategy for health care. The main purpose of this study is to strengthen the application of non‐oncological drug metformin on breast cancer treatment in the perspective of epigenetics. In the present study, metformin was found to inhibit cell proliferation, promote apoptosis and induce cell cycle arrest in breast cancer cells at a dose‐dependent manner. In addition, metformin treatment elevated acH3K9 abundance and decreased acH3K18 level. The expression of lncRNA MALAT1, HOTAIR, DICER1‐AS1, LINC01121 and TUG1 was up‐regulated by metformin treatment. In metformin‐treated cells, MALAT1 knock‐down increased the Bax/Bcl2 ratio and enhanced p21 but decreased cyclin B1 expression. The expression of Beclin1, VDAC1, LC3‐II, CHOP and Bip was promoted in the cells received combinatorial treatment of metformin and MALAT1 knock‐down. The reduced phosphorylation of c‐Myc was further decreased in the metformin‐treated cells in combination with MALAT1 knock‐down than metformin treatment alone. Taken together, these results provide a promising repurposed strategy for metformin on cancer treatment by modulating epigenetic modifiers.

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

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

Mind the replication gap

Unlike bacteria, mammalian cells need to complete DNA replication before segregating their chromosomes for the maintenance of genome integrity. Thus, cells have evolved efficient pathways to restore stalled and/or collapsed replication forks during S-phase, and when necessary, also to delay cell cycle progression to ensure replication completion. However, strong evidence shows that cells can proceed to mitosis with incompletely replicated DNA when under mild replication stress (RS) conditions. Consequently, the incompletely replicated genomic gaps form, predominantly at common fragile site regions, where the converging fork-like DNA structures accumulate. These branched structures pose a severe threat to the faithful disjunction of chromosomes as they physically interlink the partially duplicated sister chromatids. In this review, we provide an overview discussing how cells respond and deal with the under-replicated DNA structures that escape from the S/G2 surveillance system. We also focus on recent research of a mitotic break-induced replication pathway (also known as mitotic DNA repair synthesis), which has been proposed to operate during prophase in an attempt to finish DNA synthesis at the under-replicated genomic regions. Finally, we discuss recent data on how mild RS may cause chromosome instability and mutations that accelerate cancer genome evolution.

Regulation of tissue regeneration by the circadian clock

Circadian rhythms are regulated by a highly conserved transcriptional/translational feedback loop that maintains approximately 24-hr periodicity from cellular to organismal levels. Much research effort is being devoted to understanding how the outputs of the master clock affect peripheral oscillators, and in turn, numerous biological processes. Recent studies have revealed roles for circadian timing in the regulation of numerous cellular behaviours in support of complex tissue regeneration. One such role involves the interaction between the circadian clockwork and the cell cycle. The molecular mechanisms that control the cell cycle create a system of regulation that allows for high fidelity DNA synthesis, mitosis and apoptosis. In recent years, it has become clear that clock gene products are required for proper DNA synthesis and cell cycle progression, and conversely, elements of the cell cycle cascade feedback to influence molecular circadian timing mechanisms. It is through this crosstalk that the circadian system orchestrates stem cell proliferation, niche exit and control of the signalling pathways that govern differentiation and self-renewal. In this review, we discuss the evidence for circadian control of tissue homeostasis and repair and suggest new avenues for research.