Cell Cycle Control: A System of Interlinking Oscillators

Sumo-regulatory SENP2 controls the homeostatic squamous mitosis-differentiation checkpoint

Squamous or epidermoid cancer arises in stratified epithelia but also is frequent in the non-epidermoid epithelium of the lung by unclear mechanisms. A poorly studied mitotic checkpoint drives epithelial cells bearing irreparable genetic damage into epidermoid differentiation. We performed an RNA-sequencing gene search to target unknown regulators of this response and selected the SUMO regulatory protein SENP2. Alterations of SENP2 expression have been associated with some types of cancer. We found the protein to be strongly localised to mitotic spindles of freshly isolated human epidermal cells. Primary cells rapidly differentiated after silencing SENP2 with specific shRNAs. Loss of SENP2 produced in synchronised epithelial cells delays in mitotic entry and exit and defects in chromosomal alignment. The results altogether strongly argue for an essential role of SENP2 in the mitotic spindle and hence in controlling differentiation. In addition, the expression of SENP2 displayed an inverse correlation with the immuno-checkpoint biomarker PD-L1 in a pilot collection of aggressive lung carcinomas. Consistently, metastatic head and neck cancer cells that do not respond to the mitosis-differentiation checkpoint were resistant to depletion of SENP2. Our results identify SENP2 as a novel regulator of the epithelial mitosis-differentiation checkpoint and a potential biomarker in epithelial cancer.

Securinine inhibits carcinogenesis in gastric cancer by targeting AURKA-β-catenin/Akt/STAT3 and the cell cycle pathway

BACKGROUND

Gastric cancer (GC) is difficult to treat with currently available treatments. Securinine (SCR) has a lengthy history of use in the treatment of disorders of the nervous system, and its anticancer potential has been gaining attention in recent years. The aim of this study was to explore the repressive effect of SCR on GC and its fundamental mechanism.

METHODS

The efficacy of SCR in GC cells was detected by MTT assays. Colony formation, flow cytometry and Transwell assays were used to assess the changes in the proliferation, apoptosis, cell cycle distribution, migration and invasion of GC cells after treatment. AGS (human gastric carcinoma cell)-derived xenografts were used to observe the effect of SCR on tumor growth in vivo. The molecular mechanism of action of SCR in GC was explored via RNA sequencing, bioinformatics analysis, Western blotting, molecular docking, and immunohistochemistry.

RESULTS

SCR was first discovered to inhibit the proliferation, migration, and invasion of GC cells while initiating apoptosis and cell cycle arrest in vitro. It was also established that SCR has excellent anticancer effects in vivo. Interestingly, AURKA acts as a crucial target of SCR, and AURKA expression can be blocked by SCR. Moreover, this study revealed that SCR suppresses the cell cycle and the β-catenin/Akt/STAT3 pathways, which were previously reported to be regulated by AURKA.

CONCLUSION

SCR exerts a notable anticancer effect on GC by targeting AURKA and blocking the cell cycle and β-catenin/Akt/STAT3 pathway. Thus, SCR is a promising pharmacological option for the treatment of GC.

Biological role and expression of translationally controlled tumor protein (TCTP) in tumorigenesis and development and its potential for targeted tumor therapy

Translationally controlled tumor protein (TCTP), also known as histamine-releasing factor (HRF) or fortilin, is a highly conserved protein found in various species. To date, multiple studies have demonstrated the crucial role of TCTP in a wide range of cellular pathophysiological processes, including cell proliferation and survival, cell cycle regulation, cell death, as well as cell migration and movement, all of which are major pathogenic mechanisms of tumorigenesis and development. This review aims to provide an in-depth analysis of the functional role of TCTP in tumor initiation and progression, with a particular focus on cell proliferation, cell death, and cell migration. It will highlight the expression and pathological implications of TCTP in various tumor types, summarizing the current prevailing therapeutic strategies that target TCTP.

Influence of Human Bone Marrow Mesenchymal Stem Cells Secretome from Acute Myeloid Leukemia Patients on the Proliferation and Death of K562 and K562-Lucena Leukemia Cell Lineages

Leukemias are among the most prevalent types of cancer worldwide. Bone marrow mesenchymal stem cells (MSCs) participate in the development of a suitable niche for hematopoietic stem cells, and are involved in the development of diseases such as leukemias, to a yet unknown extent. Here we described the effect of secretome of bone marrow MSCs obtained from healthy donors and from patients with acute myeloid leukemia (AML) on leukemic cell lineages, sensitive (K562) or resistant (K562-Lucena) to chemotherapy drugs. Cell proliferation, viability and death were evaluated, together with cell cycle, cytokine production and gene expression of ABC transporters and cyclins. The secretome of healthy MSCs decreased proliferation and viability of both K562 and K562-Lucena cells; moreover, an increase in apoptosis and necrosis rates was observed, together with the activation of caspase 3/7, cell cycle arrest in G0/G1 phase and changes in expression of several ABC proteins and cyclins D1 and D2. These effects were not observed using the secretome of MSCs derived from AML patients. In conclusion, the secretome of healthy MSCs have the capacity to inhibit the development of leukemia cells, at least in the studied conditions. However, MSCs from AML patients seem to have lost this capacity, and could therefore contribute to the development of leukemia.

An update of predictive biomarkers related to WEE1 inhibition in cancer therapy

PURPOSE

WEE1 is a crucial kinase involved in the regulation of G2/M checkpoint within the cell cycle. This article aims to comprehensively review the existing knowledge on the implication of WEE1 as a therapeutic target in tumor progression and drug resistance. Furthermore, we summarize the current predictive biomarkers employed to treat cancer with WEE1 inhibitors.

METHODS

A systematic review of the literature was conducted to analyze the association between WEE1 inhibition and cancer progression, including tumor advancement and drug resistance. Special attention was paid to the identification and utilization of predictive biomarkers related to therapeutic response to WEE1 inhibitors.

RESULTS

The review highlights the intricate involvement of WEE1 in tumor progression and drug resistance. It synthesizes the current knowledge on predictive biomarkers employed in WEE1 inhibitor treatments, offering insights into their prognostic significance. Notably, the article elucidates the potential for precision medicine by understanding these biomarkers in the context of tumor treatment outcomes.

CONCLUSION

WEE1 plays a pivotal role in tumor progression and is a promising therapeutic target. Distinguishing patients that would benefit from WEE1 inhibition will be a major direction of future research.

A co-formulation of interferons alpha2b and gamma distinctively targets cell cycle in the glioblastoma-derived cell line U-87MG

BACKGROUND

HeberFERON is a co-formulation of α2b and γ interferons, based on their synergism, which has shown its clinical superiority over individual interferons in basal cell carcinomas. In glioblastoma (GBM), HeberFERON has displayed promising preclinical and clinical results. This led us to design a microarray experiment aimed at identifying the molecular mechanisms involved in the distinctive effect of HeberFERON compared to the individual interferons in U-87MG model.

METHODS

Transcriptional expression profiling including a control (untreated) and three groups receiving α2b-interferon, γ-interferon and HeberFERON was performed using an Illumina HT-12 microarray platform. Unsupervised methods for gene and sample grouping, identification of differentially expressed genes, functional enrichment and network analysis computational biology methods were applied to identify distinctive transcription patterns of HeberFERON. Validation of most representative genes was performed by qPCR. For the cell cycle analysis of cells treated with HeberFERON for 24 h, 48 and 72 h we used flow cytometry.

RESULTS

The three treatments show different behavior based on the gene expression profiles. The enrichment analysis identified several mitotic cell cycle related events, in particular from prometaphase to anaphase, which are exclusively targeted by HeberFERON. The FOXM1 transcription factor network that is involved in several cell cycle phases and is highly expressed in GBMs, is significantly down regulated. Flow cytometry experiments corroborated the action of HeberFERON on the cell cycle in a dose and time dependent manner with a clear cellular arrest as of 24 h post-treatment. Despite the fact that p53 was not down-regulated, several genes involved in its regulatory activity were functionally enriched. Network analysis also revealed a strong relationship of p53 with genes targeted by HeberFERON. We propose a mechanistic model to explain this distinctive action, based on the simultaneous activation of PKR and ATF3, p53 phosphorylation changes, as well as its reduced MDM2 mediated ubiquitination and export from the nucleus to the cytoplasm. PLK1, AURKB, BIRC5 and CCNB1 genes, all regulated by FOXM1, also play central roles in this model. These and other interactions could explain a G2/M arrest and the effect of HeberFERON on the proliferation of U-87MG.

CONCLUSIONS

We proposed molecular mechanisms underlying the distinctive behavior of HeberFERON compared to the treatments with the individual interferons in U-87MG model, where cell cycle related events were highly relevant.

Bisphenol A exposure inhibits vascular smooth muscle cell responses: Involvement of proliferation, migration, and invasion

Previous studies have associated bisphenol A (BPA) with malignant tumor formation, infertility, and atherosclerosis in vitro and in vivo. However, the precise mechanisms through which BPA affects the cardiovascular system under normal conditions remain unclear. Therefore, this study investigated the biological mechanisms through which BPA affects the responses of aortic vascular smooth muscle cells (VSMCs). BPA treatment inhibited the proliferative activity of VSMCs and induced G₂/M-phase cell cycle arrest via stimulation of the ATM-CHK2-Cdc25C-p21^WAF1-Cdc2 cascade in VSMCs. Furthermore, BPA treatment upregulated the phosphorylation of mitogen-activated protein kinase (MAPK) pathways such as ERK, JNK, and p38 MAPK in VSMCs. However, the phosphorylation level of AKT was down-regulated by BPA treatment. Additionally, the phosphorylation of ERK, JNK, and p38 MAPK was suppressed when the cells were treated with their respective inhibitors (U0126, SP600125, and SB203580). BPA suppressed MMP-9 activity by reducing the binding activity of AP-1, Sp-1, and NF-κB, thus inhibiting the invasive and migratory ability of VSMCs. These data demonstrate that BPA interferes with the proliferation, migration, and invasion capacities of VSMCs. Therefore, our findings suggest that overexposure to BPA can lead to cardiovascular damage due to dysregulated VSMC responses.

Malignant growth of arsenic-transformed cells depends on activated Akt induced by reactive oxygen species

Arsenic is an identified carcinogen for humans.In this study, chronic exposure of human hepatocyte L-02 to low-doses of inorganic arsenic caused cell malignant proliferation. Meanwhile, compared with normal L-02 cells, arsenic-transformed malignant cells, L-02-As displayed more ROS and significantly higher Cyclin D1 expression as well as aerobic glycolysis. Moreover, Akt activation is followed by the upregulation of Cyclin D1 and HK2 expression in L-02-As cells, since inhibition of Akt activity by Ly294002 attenuated the colony formation in soft agar and decreased the levels of Cyclin D1 and HK2. In addition, scavenging of ROS by NAC resulted in a decreased expression of phospho-Akt, HK2 and Cyclin D1, and attenuates the ability of anchorage-independent growth ofL-02-As cells, suggested that ROS mediated the Akt activation in L-02-As cells. In summary, our results demonstrated that ROS contributes to the malignant phenotype of arsenic-transformed human hepatocyte L-02-As via the activation of Akt pathway.

Drugging Hijacked Kinase Pathways in Pediatric Oncology: Opportunities and Current Scenario

Childhood cancer is considered rare, corresponding to ~3% of all malignant neoplasms in the human population. The World Health Organization (WHO) reports a universal occurrence of more than 15 cases per 100,000 inhabitants around the globe, and despite improvements in diagnosis, treatment and supportive care, one child dies of cancer every 3 min. Consequently, more efficient, selective and affordable therapeutics are still needed in order to improve outcomes and avoid long-term sequelae. Alterations in kinases' functionality is a trademark of cancer and the concept of exploiting them as drug targets has burgeoned in academia and in the pharmaceutical industry of the 21st century. Consequently, an increasing plethora of inhibitors has emerged. In the present study, the expression patterns of a selected group of kinases (including tyrosine receptors, members of the PI3K/AKT/mTOR and MAPK pathways, coordinators of cell cycle progression, and chromosome segregation) and their correlation with clinical outcomes in pediatric solid tumors were accessed through the R2: Genomics Analysis and Visualization Platform and by a thorough search of published literature. To further illustrate the importance of kinase dysregulation in the pathophysiology of pediatric cancer, we analyzed the vulnerability of different cancer cell lines against their inhibition through the Cancer Dependency Map portal, and performed a search for kinase-targeted compounds with approval and clinical applicability through the CanSAR knowledgebase. Finally, we provide a detailed literature review of a considerable set of small molecules that mitigate kinase activity under experimental testing and clinical trials for the treatment of pediatric tumors, while discuss critical challenges that must be overcome before translation into clinical options, including the absence of compounds designed specifically for childhood tumors which often show differential mutational burdens, intrinsic and acquired resistance, lack of selectivity and adverse effects on a growing organism.

Repurposed benzydamine targeting CDK2 suppresses the growth of esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of the leading causes of cancer death worldwide. It is urgent to develop new drugs to improve the prognosis of ESCC patients. Here, we found benzydamine, a locally acting non-steroidal anti-inflammatory drug, had potent cytotoxic effect on ESCC cells. Benzydamine could suppress ESCC proliferation in vivo and in vitro. In terms of mechanism, CDK2 was identified as a target of benzydamine by molecular docking, pull-down assay and in vitro kinase assay. Specifically, benzydamine inhibited the growth of ESCC cells by inhibiting CDK2 activity and affecting downstream phosphorylation of MCM2, c-Myc and Rb, resulting in cell cycle arrest. Our study illustrates that benzydamine inhibits the growth of ESCC cells by downregulating the CDK2 pathway.

Abnormal expression of cortical cell cycle regulators underlying anxiety and depressive-like behavior in mice exposed to chronic stress

Background

The cell cycle is a critical mechanism for proper cellular growth, development and viability. The p16^INK4a and p21^Waf1/Cip1 are important regulators of the cell cycle progression in response to internal and external stimuli (e.g., stress). Accumulating evidence indicates that the prefrontal cortex (PFC) is particularly vulnerable to stress, where stress induces, among others, molecular and morphological alterations, reflecting behavioral changes. Here, we investigated if the p16^INK4a and p21^Waf1/Cip1 expression are associated with behavioral outcomes.

Methods

Prefrontal cortex mRNA and protein levels of p16^INK4A and p21^Waf1/Cip1 of mice (six independent groups of C57BL/6J, eight mice/group, 50% female) exposed from 0 to 35 days of chronic restraint stress (CRS) were quantified by qPCR and Western Blot, respectively. Correlation analyses were used to investigate the associations between cyclin-dependent kinase inhibitors (CKIs) expression and anxiety- and depression-like behaviors.

Results

Our results showed that the PFC activated the cell cycle regulation pathways mediated by both CKIs p16^INK4A and p21^Waf1/Cip1 in mice exposed to CRS, with overall decreased mRNA expression and increased protein expression. Moreover, correlation analysis revealed that mRNA and protein levels are statistically significant correlated with anxiety and depressive-like behavior showing a greater effect in males than females.

Conclusion

Our present study extends the existing literature providing evidence that PFC cells respond to chronic stress exposure by overexpressing CKIs. Furthermore, our findings indicated that abnormal expression of p16^INK4A and p21^Waf1/Cip1 may significantly contribute to non-adaptive behavioral responses.

Genome-scale RNA interference profiling of Trypanosoma brucei cell cycle progression defects

Trypanosomatids, which include major pathogens of humans and livestock, are flagellated protozoa for which cell cycle controls and the underlying mechanisms are not completely understood. Here, we describe a genome-wide RNA-interference library screen for cell cycle defects in Trypanosoma brucei. We induced massive parallel knockdown, sorted the perturbed population using high-throughput flow cytometry, deep-sequenced RNAi-targets from each stage and digitally reconstructed cell cycle profiles at a genomic scale; also enabling data visualisation using an online tool ( https://tryp-cycle.pages.dev/ ). Analysis of several hundred genes that impact cell cycle progression reveals >100 flagellar component knockdowns linked to genome endoreduplication, evidence for metabolic control of the G₁-S transition, surface antigen regulatory mRNA-binding protein knockdowns linked to G₂M accumulation, and a putative nucleoredoxin required for both mitochondrial genome segregation and for mitosis. The outputs provide comprehensive functional genomic evidence for the known and novel machineries, pathways and regulators that coordinate trypanosome cell cycle progression.

Temporal changes in cyclinD-CDK4/CDK6 and cyclinE-CDK2 pathways: implications for the mechanism of deficient decidualization in an immune-based mouse model of unexplained recurrent spontaneous abortion

BACKGROUND

Deficient endometrial decidualization has been associated with URSA. However, the underlying mechanism is poorly understood. This study aimed to investigate the temporal cytokine changes and the involvement of CyclinD-CDK4/6 and CyclinE-CDK2 pathways in the regulation of the G1 phase of the cell cycle during decidualization in a murine model of URSA.

METHODS

Serum and decidual tissues of mice were collected from GD4 to GD8. The embryo resorption and abortion rates were observed on GD8 and the decidual tissue status was assessed. In addition, PRL, Cyclin D, CDK6, CDK4, Cyclin E, CDK2 expression in mice were measured.

RESULTS

URSA mice showed high embryo resorption rate and PRL, Cyclin D, Cyclin E CDK2, CDK4, CDK6 down-regulation during decidualization. The hyperactivated Cyclin D-CDK4/CDK6 and cyclin E/CDK2 pathways inhibit the decidualization process and leading to deficient decidualization.

CONCLUSION

Insufficient decidualization is an important mechanism of URSA. which is related to the decrease of Cyclin D、Cyclin E、 CDK2、CDK4 and CDK6 in decidualization process of URSA.

Cell Cycle Progression Influences Biofilm Formation in Saccharomyces cerevisiae 1308

Biofilm-immobilized continuous fermentation is a novel fermentation strategy that has been utilized in ethanol fermentation. Continuous fermentation contributes to the self-proliferation of Saccharomyces cerevisiae biofilms. Previously, we successfully described the cell cycle differences between biofilm-immobilized fermentation and calcium alginate-immobilized fermentation. In the present study, we investigated the relationship between biofilm formation and the cell cycle. We knocked down CLN3, SIC1, and ACE2 and found that Δcln3 and Δsic1 exhibited a predominance of G₂/M phase cells, increased biofilm formation, and significantly increased extracellular polysaccharide formation and expression of genes in the FLO gene family during immobilisation fermentation. Δace2 exhibited a contrasting performance. These findings suggest that the increase in the proportion of cells in the G₂/M phase of the cell cycle facilitates biofilm formation and that the cell cycle influences biofilm formation by regulating cell adhesion and polysaccharide formation. This opens new avenues for basic research and may also help to provide new ideas for biofilm prevention and optimization. IMPORTANCE Immobilised fermentation can be achieved using biofilm resistance, resulting in improved fermentation efficiency and yield. The link between the cell cycle and biofilms deserves further study since reports are lacking in this area. This study showed that the ability of Saccharomyces cerevisiae to produce biofilm differed when cell cycle progression was altered. Further studies suggested that cell cycle regulatory genes influenced biofilm formation by regulating cell adhesion and polysaccharide formation. Findings related to cell cycle regulation of biofilm formation set the stage for biofilm in Saccharomyces cerevisiae and provide a theoretical basis for the development of a new method to improve biofilm-based industrial fermentation.

The exon 12-containing LHX6 isoforms promote cervical cancer cell proliferation by regulating the MAPK signaling pathway

LIM homeobox 6 (LHX6) has been reported to be downregulated and inhibits cell proliferation in various cancers. Alternative splicing of LHX6 leads to six annotated isoforms, which can be found in the NCBI database. However, the expression patterns and potential roles of these isoforms remain poorly characterized in cervical cancer. Here, we demonstrated that the LHX6 isoforms containing exon 12 (LHX6^EX(+12) group) and isoforms lacking exon 12 (LHX6^EX(-12) group) were differentially expressed in cervical tissue by qRT-PCR. The mRNA expression level of LHX6^EX(+12) group was higher than that of LHX6^EX(-12) group in cervical cancer tissue. Knockdown of LHX6^EX(+12) group and all LHX6 isoforms (LHX6^All group) inhibited cell growth, increased cell apoptosis, and induced cell cycle arrest from G0/G1 phase to S phase in vitro. Consistently, overexpression of the LHX6^EX(+12) group promoted cervical cancer cell proliferation in vitro. In contrast, no significant differences in cell proliferation were found between LHX6^EX(-12) isoform knockdown group and its control. RNA-sequencing suggested that the LHX6^EX(+12) isoform group might exert its cancer-promoting effects in cervical cancer via regulating MAPK signaling pathway. Downregulation of the LHX6^EX(+12) group significantly suppressed the phosphorylation of MRK, ERK, JNK, and P38 at the protein level. We also identified some unique biological processes and signaling pathways in which each isoform group might be involved. In summary, our results indicated that LHX6^EX(+12) isoform group was the dominant oncogenic type of LHX6 in cervical cancer, which may be a new biomarker and a potential precise therapeutic target for cervical cancer in the future.

LncRNA TARID induces cell proliferation through cell cycle pathway associated with coronary artery disease

BACKGROUND/AIM

Long non-coding RNA TARID (lncRNA TARID) can activate the tumor suppressor TCF21 in tumorigenesis by inducing promoter demethylation. However, the impact on lncRNA TARID and its variants of coronary artery disease (CAD) are poorly understood.

METHODS

We performed a case-control study enrolling 949 cases and 892 controls to assess genotype. Five variants were genotyped by TaqMan assay. 20 cases and 20 controls were used to evaluate the expression of lncRNA TARID. The cell proliferation rate was evaluated by CCK-8. The RT-qPCR and cell cycle analysis were applied to examine cell proliferation-related mRNA and cell distribution.

RESULTS

This study indicated that rs2327433 GG genotype was associated with CAD risk adjusting for traditional risk factors (OR = 2.74, 95%CI: 1.10-6.83, P = 0.03). Our results analyses revealed that the genotype of rs2327433 was related to the proportion of CAD patients with left anterior descending artery disease and left circumflex artery disease (P = 0.025 and P = 0.025, respectively). The results showed that the minor allele frequency of rs2327433 was significantly correlated with the severity of the disease (P = 0.029). The eQTL analysis showed that rs2327433 may affect the transcription factors TCF21 regulated by lncRNA TARID. We found that TARID silencing regulated cell proliferation and altered cell cycle progression by induced upregulation of CDK1 and PCNA.

CONCLUSIONS

SNP rs2327433 in lncRNA TARID was associated with CAD risk and the severity of CAD in the Chinese Han population. Furthermore, SNP rs2327433 may affect the expression of atherosclerosis-related transcription factor TCF21 regulated by lncRNA TARID. Finally, our study provided a new lncRNA-dictated regulatory mechanism participating in cell proliferation.

CPE Regulates Proliferation and Apoptosis of Primary Myocardial Cells Mediated by Ischemia and Hypoxia Injury

Objective

To observe the effect of carboxypeptidase E (CPE) on the ischemia and hypoxia (I/H) injury of primary cardiomyocytes.

Methods

Quantitative real-time polymerase chain reaction (qRT-PCR) technology was used to detect the expression of CPE in sham and myocardial infarction (MI) rat heart tissue, and the plasmid was transferred into primary cardiomyocytes by transfection technology. The apoptosis rate of cardiomyocytes was detected by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) staining, Annexin V-PI staining, and Cell Counting Kit-8 (CCK-8) assay. In addition, Caspase kit and qRT-PCR technology were used to detect the expression of apoptosis-related factors. The cell proliferation was detected by 5-ethynyl-2'-deoxyuridine (EdU) staining, flow cytometry, and qRT-PCR technology. In addition, Western blotting (WB) and qRT-PCR techniques were used to detect the Wnt/β-catenin pathway.

Results

First, we found that the expression of CPE in the marginal zone of MI was obviously reduced. Overexpression of CPE in primary cardiomyocytes can effectively inhibit ischemia/hypoxia (I/H)-induced apoptosis and decreased cell activity. In addition, CPE can promote cell proliferation and relieve the inhibitory effect of I/H on cardiomyocytes. At the same time, CPE can promote the expression of β-catenin and c-myc.

Conclusion

Overexpression of CPE in primary cardiomyocytes can effectively alleviate the decreased cell activity, increased apoptosis, and decreased proliferation caused by I/H and regulated by Wnt/β-catenin pathway.

Fumonisin B1 Inhibits Cell Proliferation and Decreases Barrier Function of Swine Umbilical Vein Endothelial Cells

The fumonisins are a group of common mycotoxins found around the world that mainly contaminate maize. As environmental toxins, they pose a threat to human and animal health. Fumonisin B₁ (FB₁) is the most widely distributed and the most toxic. FB₁ can cause pulmonary edema in pigs. However, the current toxicity mechanism of fumonisins is still in the exploratory stage, which may be related to sphingolipid metabolism. Our study is designed to investigate the effect of FB₁ on the cell proliferation and barrier function of swine umbilical vein endothelial cells (SUVECs). We show that FB₁ can inhibit the cell viability of SUVECs. FB₁ prevents cells from entering the S phase from the G1 phase by regulating the expression of the cell cycle-related genes cyclin B1, cyclin D1, cyclin E1, Cdc25c, and the cyclin-dependent kinase-4 (CDK-4). This results in an inhibition of cell proliferation. In addition, FB₁ can also change the cell morphology, increase paracellular permeability, destroy tight junctions and the cytoskeleton, and reduce the expression of tight junction-related genes claudin 1, occludin, and ZO-1. This indicates that FB₁ can cause cell barrier dysfunction of SUVECs and promote the weakening or even destruction of the connections between endothelial cells. In turn, this leads to increased blood vessel permeability and promotes exudation. Our findings suggest that FB₁ induces toxicity in SUVECs by affecting cell proliferation and disrupting the barrier function.

Integration of Transcriptome and Methylome Highlights the Roles of Cell Cycle and Hippo Signaling Pathway in Flatfish Sexual Size Dimorphism

Sexual size dimorphism (SSD) is the difference in segments or body size between sexes prevalent in various species. Understanding the genetic architecture of SSD has remained a significant challenge owing to the complexity of growth mechanisms and the sexual influences among species. The Chinese tongue sole (Cynoglossus semilaevis), which exhibits a female-biased SSD and sex reversal from female to pseudomale, is an ideal model for exploring SSD mechanism at the molecular level. The present study aimed to integrate transcriptome and methylome analysis to unravel the genetic and epigenetic changes in female, male, and pseudomale C. semilaevis. The somatotropic and reproductive tissues (brain, liver, gonad, and muscle) transcriptomes were characterized by RNA-seq technology. Transcriptomic analysis unravelled numerous differentially expressed genes (DEGs) involved in cell growth and death-related pathways. The gonad and muscle methylomes were further employed for screening differentially methylated genes (DMGs). Relatively higher DNA methylation levels were observed in the male and pseudomale individuals. In detail, hypermethylation of the chromosome W was pronounced in the pseudomale group than in the female group. Furthermore, weighted gene co-expression network analysis showed that turquoise and brown modules positively and negatively correlated with the female-biased SSD, respectively. A combined analysis of the module genes and DMGs revealed the female-biased mRNA transcripts and hypomethylated levels in the upstream and downstream regions across the cell cycle-related genes. Moreover, the male and pseudomale-biased gene expression in the hippo signaling pathway were positively correlated with their hypermethylation levels in the gene body. These findings implied that the activation of the cell cycle and the inhibition of the hippo signaling pathway were implicated in C. semilaevis female-biased SSD. In addition, the dynamic expression pattern of the epigenetic regulatory factors, including dnmt1, dnmt3a, dnmt3b, and uhrf1, among the different sexes correspond with their distinct DNA methylation levels. Herein, we provide valuable clues for understanding female-biased SSD in C. semilaevis.

Long Noncoding RNAs PTPRG Antisense RNA 1 Targets Cyclin D1 to Facilitate Cell Proliferation in Lung Adenocarcinoma

Background: Numerous studies have recorded the function of long noncoding RNAs (lncRNAs) in cancer development, including lung adenocarcinoma (LUAD). Previous studies have reported the crucial role of lncRNA PTPRG antisense RNA 1 (PTPRG-AS1) in various cancers. However, the role of PTPRG-AS1 in LUAD remains unknown. Materials and Methods: Real-time quantitative polymerase chain reaction (RT-qPCR) was applied for detecting PTPRG-AS1 expression in LUAD cell lines. Functional assays and in vivo experiments explored cell proliferation, whereas flow cytometry analysis was used to detect cell cycle. In addition, fluorescent in situ hybridization (FISH) and subcellular fractionation assay measured the localization of PTPRG-AS1 in LUAD cells. RNA pulldown, luciferase reporter, and RNA immunoprecipitation (RIP) assays were used to investigate the interaction of PTPRG-AS1/miR-124-3p/cyclin D1 (CCND1) axis. Results: PTPRG-AS1 expression was notably high in LUAD cell lines. PTPRG-AS1 knockdown suppressed cell proliferation and cycle as well as the level of CCND1. Moreover, miR-124-3p was the mutual target of PTPRG-AS1 and CCND1. In addition, PTPRG-AS1 sponged miR-124-3p to upregulate CCND1 in LUAD cells. Moreover, miR-124-3p depletion reversed the suppression of PTPRG-AS1 silence on LUAD cell behaviors, but then CCND1 knockdown countervailed the promoting influence of downregulated miR-124-3p. Conclusions: PTPRG-AS1 propels cell proliferation and cell cycle of LUAD by targeting miR-124-3p/CCND1 axis.

Quantitative differences between cyclin-dependent kinases underlie the unique functions of CDK1 in human cells

One of the most intriguing features of cell-cycle control is that, although there are multiple cyclin-dependent kinases (CDKs) in higher eukaryotes, a single CDK is responsible for both G₁-S and G₂-M in yeasts. By leveraging a rapid conditional silencing system in human cell lines, we confirm that CDK1 assumes the role of G₁-S CDK in the absence of CDK2. Unexpectedly, CDK1 deficiency does not prevent mitotic entry. Nonetheless, inadequate phosphorylation of mitotic substrates by noncanonical cyclin B-CDK2 complexes does not allow progression beyond metaphase and underscores deleterious late mitotic events, including the uncoupling of anaphase A and B and cytokinesis. Elevation of CDK2 to a level similar to CDK1 overcomes the mitotic defects caused by CDK1 deficiency, indicating that the relatively low concentration of CDK2 accounts for the defective anaphase. Collectively, these results reveal that the difference between G₂-M and G₁-S CDKs in human cells is essentially quantitative.

Wee1 Kinase: A Potential Target to Overcome Tumor Resistance to Therapy

During the cell cycle, DNA suffers several lesions that need to be repaired prior to entry into mitosis to preserve genome integrity in daughter cells. Toward this aim, cells have developed complex enzymatic machinery, the so-called DNA damage response (DDR), which is able to repair DNA, temporarily stopping the cell cycle to provide more time to repair, or if the damage is too severe, inducing apoptosis. This DDR mechanism is considered the main source of resistance to DNA-damaging therapeutic treatments in oncology. Recently, cancer stem cells (CSCs), which are a small subset of tumor cells, were identified as tumor-initiating cells. CSCs possess self-renewal potential and persistent tumorigenic capacity, allowing for tumor re-growth and relapse. Compared with cancer cells, CSCs are more resistant to therapeutic treatments. Wee1 is the principal gatekeeper for both G2/M and S-phase checkpoints, where it plays a key role in cell cycle regulation and DNA damage repair. From this perspective, Wee1 inhibition might increase the effectiveness of DNA-damaging treatments, such as radiotherapy, forcing tumor cells and CSCs to enter into mitosis, even with damaged DNA, leading to mitotic catastrophe and subsequent cell death.

Downregulation of microRNA-6125 promotes colorectal cancer growth through YTHDF2-dependent recognition of N6-methyladenosine-modified GSK3β

BACKGROUND

MicroRNAs (miRNAs), the key regulator of gene expression, and N6-methyladenosine (m6A) RNA modification play a significant role in tumour progression. However, regulation of m6A-modified mRNAs by miRNAs in colorectal cancer (CRC), and its effect on progression of CRC, remains to be investigated.

METHODS

Expression of miR-6125 and YTH Domain-Containing Family Protein 2 (YTHDF2) was detected by western blotting and immunohistochemistry. The effects of miR-6125 and YTHDF2 on proliferative capacity of CRC cells were analysed using soft agar, ATP, CCK8 and EdU assays, and in animal experiments.

RESULTS

MiR-6125 expression was downregulated markedly in CRC, and expression correlated negatively with tumour size and prognosis. MiR-6125 targeted the 3'-UTR of YTHDF2 and downregulated the YTHDF2 protein, thereby increasing the stability of m6A-modified glycogen synthase kinase 3 beta (GSK3β) mRNA. Increased GSK3β protein levels inhibited the expression of Wnt/β-catenin/Cyclin D1 pathway-related proteins, leading to G0-G1 phase arrest and ultimately inhibiting the proliferation of CRC cells.

CONCLUSIONS

MiR-6125 regulates YTHDF2 and thus plays a critical role in regulating the Wnt/β-catenin pathway, thereby affecting the growth of CRC. Collectively, these results suggest that miR-6125 and YTHDF2 are potential targets for treatment of CRC.

Chemotherapy resistance in epithelial ovarian cancer: Mechanisms and emerging treatments

Ovarian cancer (OC) remains a fatal malignancy because most patients experience recurrent disease, which is resistant to chemotherapy. The outcomes for patients with platinum-resistant OC are poor, response rates to further chemotherapy are low and median survival is lower than 12 months. The complexity of platinum-resistant OC, which comprises a heterogeneous spectrum of diseases, is indeed far from being completely understood. Therefore, comprehending tumors' biological behaviour to identify reliable biomarkers, which may predict responses to therapies, is a demanding challenge to improve OC management. In the age of precision medicine, efforts to overcome platinum resistance in OC represent a dynamic and vast field in which innovative drugs and clinical trials rapidly develop. This review will present the exceptional biochemical environment implicated in OC and highlights mechanisms of chemoresistance. Furthermore, innovative molecules and new therapeutic opportunities are presented, along with currently available therapies and ongoing clinical trials.

Cyclin-dependent kinase (CDK) inhibitors in solid tumors: a review of clinical trials

Cyclin-dependent kinases (CDKs) play a key regulating role in the cell cycle, which is almost universally altered in cancer, leading to sustained proliferation. Early pan-CDK inhibitors showed poor results in clinical trials for solid malignancies, as the lack of selectivity produced significant toxicity. The production of more selective inhibitors led to significant developments in cancer therapy, as CDK4/6 inhibitors in combination with endocrine therapy changed the landscape of the treatment of hormone-receptor positive (HR +) metastatic breast cancer. Recently, Trilaciclib demonstrated benefits regarding hematological toxicity compared to placebo when administered in combination with chemotherapy in small cell lung cancer. Newer agents, such as SY-5609, a selective CDK7 inhibitor, have also shown promising results in early clinical trials. In this paper, we review the data from clinical trials of CDK inhibitors in solid tumors, either as a monotherapy or in combination with other agents, with an emphasis on novel agents and potential new indications for this drug class.

The Mammalian Family of Katanin Microtubule-Severing Enzymes

The katanin family of microtubule-severing enzymes is critical for cytoskeletal rearrangements that affect key cellular processes like division, migration, signaling, and homeostasis. In humans, aberrant expression, or dysfunction of the katanins, is linked to developmental, proliferative, and neurodegenerative disorders. Here, we review current knowledge on the mammalian family of katanins, including an overview of evolutionary conservation, functional domain organization, and the mechanisms that regulate katanin activity. We assess the function of katanins in dividing and non-dividing cells and how their dysregulation promotes impaired ciliary signaling and defects in developmental programs (corticogenesis, gametogenesis, and neurodevelopment) and contributes to neurodegeneration and cancer. We conclude with perspectives on future katanin research that will advance our understanding of this exciting and dynamic class of disease-associated enzymes.

Molecular mechanisms and associated cell signalling pathways underlying the anticancer properties of phytochemical compounds from Aloe species (Review)

Naturally occurring components from various species of Aloe have been used as traditional folk medicine since the ancient times. Over the last few decades, the therapeutic effects of extracts and phytochemical compounds obtained from Aloe vera have been proven in preclinical and clinical studies. Recently, compounds from other Aloe species apart from Aloe vera have been investigated for the treatment of different diseases, with a particular focus on cancer. In the present review, the effects of phytochemical compounds obtained from different Aloe species are discussed, with a specific focus on the effects on cell signalling in cancer and normal cells, and their selectivity and efficacy. This information will be useful for the application of Aloe-derived compounds as therapeutic agents, either alone or in combination with other standard drugs for cancer treatment.

When Good Kinases Go Rogue: GSK3, p38 MAPK and CDKs as Therapeutic Targets for Alzheimer's and Huntington's Disease

Alzheimer's disease (AD) is a mostly sporadic brain disorder characterized by cognitive decline resulting from selective neurodegeneration in the hippocampus and cerebral cortex whereas Huntington's disease (HD) is a monogenic inherited disorder characterized by motor abnormalities and psychiatric disturbances resulting from selective neurodegeneration in the striatum. Although there have been numerous clinical trials for these diseases, they have been unsuccessful. Research conducted over the past three decades by a large number of laboratories has demonstrated that abnormal actions of common kinases play a key role in the pathogenesis of both AD and HD as well as several other neurodegenerative diseases. Prominent among these kinases are glycogen synthase kinase (GSK3), p38 mitogen-activated protein kinase (MAPK) and some of the cyclin-dependent kinases (CDKs). After a brief summary of the molecular and cell biology of AD and HD this review covers what is known about the role of these three groups of kinases in the brain and in the pathogenesis of the two neurodegenerative disorders. The potential of targeting GSK3, p38 MAPK and CDKS as effective therapeutics is also discussed as is a brief discussion on the utilization of recently developed drugs that simultaneously target two or all three of these groups of kinases. Multi-kinase inhibitors either by themselves or in combination with strategies currently being used such as immunotherapy or secretase inhibitors for AD and knockdown for HD could represent a more effective therapeutic approach for these fatal neurodegenerative diseases.

Cell cycle dependence on the mevalonate pathway: Role of cholesterol and non-sterol isoprenoids

The mevalonate pathway is responsible for the synthesis of isoprenoids, including sterols and other metabolites that are essential for diverse biological functions. Cholesterol, the main sterol in mammals, and non-sterol isoprenoids are in high demand by rapidly dividing cells. As evidence of its importance, many cell signaling pathways converge on the mevalonate pathway and these include those involved in proliferation, tumor-promotion, and tumor-suppression. As well as being a fundamental building block of cell membranes, cholesterol plays a key role in maintaining their lipid organization and biophysical properties, and it is crucial for the function of proteins located in the plasma membrane. Importantly, cholesterol and other mevalonate derivatives are essential for cell cycle progression, and their deficiency blocks different steps in the cycle. Furthermore, the accumulation of non-isoprenoid mevalonate derivatives can cause DNA replication stress. Identification of the mechanisms underlying the effects of cholesterol and other mevalonate derivatives on cell cycle progression may be useful in the search for new inhibitors, or the repurposing of preexisting cholesterol biosynthesis inhibitors to target cancer cell division. In this review, we discuss the dependence of cell division on an active mevalonate pathway and the role of different mevalonate derivatives in cell cycle progression.

CDK4/6 Inhibitors in Melanoma: A Comprehensive Review

Historically, metastatic melanoma was considered a highly lethal disease. However, recent advances in drug development have allowed a significative improvement in prognosis. In particular, BRAF/MEK inhibitors and anti-PD1 antibodies have completely revolutionized the management of this disease. Nonetheless, not all patients derive a benefit or a durable benefit from these therapies. To overtake this challenges, new clinically active compounds are being tested in the context of clinical trials. CDK4/6 inhibitors are drugs already available in clinical practice and preliminary evidence showed a promising activity also in melanoma. Herein we review the available literature to depict a comprehensive landscape about CDK4/6 inhibitors in melanoma. We present the molecular and genetic background that might justify the usage of these drugs, the preclinical evidence, the clinical available data, and the most promising ongoing clinical trials.

The Involvement of Ubiquitination Machinery in Cell Cycle Regulation and Cancer Progression

The cell cycle is a collection of events by which cellular components such as genetic materials and cytoplasmic components are accurately divided into two daughter cells. The cell cycle transition is primarily driven by the activation of cyclin-dependent kinases (CDKs), which activities are regulated by the ubiquitin-mediated proteolysis of key regulators such as cyclins, CDK inhibitors (CKIs), other kinases and phosphatases. Thus, the ubiquitin-proteasome system (UPS) plays a pivotal role in the regulation of the cell cycle progression via recognition, interaction, and ubiquitination or deubiquitination of key proteins. The illegitimate degradation of tumor suppressor or abnormally high accumulation of oncoproteins often results in deregulation of cell proliferation, genomic instability, and cancer occurrence. In this review, we demonstrate the diversity and complexity of the regulation of UPS machinery of the cell cycle. A profound understanding of the ubiquitination machinery will provide new insights into the regulation of the cell cycle transition, cancer treatment, and the development of anti-cancer drugs.

Iridin Induces G2/M Phase Cell Cycle Arrest and Extrinsic Apoptotic Cell Death through PI3K/AKT Signaling Pathway in AGS Gastric Cancer Cells

Iridin is a natural flavonoid found in Belamcanda chinensis documented for its broad spectrum of biological activities like antioxidant, antitumor, and antiproliferative effects. In the present study, we have investigated the antitumor potential of iridin in AGS gastric cancer cells. Iridin treatment decreases AGS cell growth and promotes G2/M phase cell cycle arrest by attenuating the expression of Cdc25C, CDK1, and Cyclin B1 proteins. Iridin-treatment also triggered apoptotic cell death in AGS cells, which was verified by cleaved Caspase-3 (Cl- Caspase-3) and poly ADP-ribose polymerase (PARP) protein expression. Further apoptotic cell death was confirmed by increased apoptotic cell death fraction shown in allophycocyanin (APC)/Annexin V and propidium iodide staining. Iridin also increased the expression of extrinsic apoptotic pathway proteins like Fas, FasL, and cleaved Caspase-8 in AGS cells. On the contrary, iridin-treated AGS cells did not show variations in proteins related to an intrinsic apoptotic pathway such as Bax and Bcl-xL. Besides, Iridin showed inhibition of PI3K/AKT signaling pathways by downregulation of (p-PI3K, p-AKT) proteins in AGS cells. In conclusion, these data suggest that iridin has anticancer potential by inhibiting PI3K/AKT pathway. It could be a basis for further drug design in gastric cancer treatment.

Long non-coding RNA DICER1-AS1-low expression in arsenic-treated A549 cells inhibits cell proliferation by regulating the cell cycle pathway

Arsenic, an environmental pollution with diverse toxicities, incurs public health problems. Arsenic trioxide could inhibit cell proliferation in vitro experiments, but the underlying mechanisms are not fully known. LncRNAs are also involved in the arsenic-induced toxicological responses. In our study, we found that the expression of lncRNA DICER1-AS1 was significantly inhibited by sodium arsenite in a dose-dependent manner. DICER1-AS1 silencing decreased the A549 cell proliferation and inhibited cell cycle progression. Importantly, DICER1-AS1 silencing induced upregulation of p21 and downregulation of Cyclin A2, Cyclin E2, CDK1 and PCNA. In conclusion, our study provided a new lncRNA-dictated regulatory mechanism participating in arsenic-induced inhibition of cell proliferation.

Oscillating waves of Fox, Cyclin and CDK gene expression indicate unique spatiotemporal control of cell cycling during nervous system development in onychophorans

Forkhead box (Fox) genes code for a class of transcription factors with many different fundamental functions in animal development including cell cycle control. Other important factors of cell cycle control are Cyclins and Cyclin-dependent kinases (CDKs). Here we report on the oscillating expression of three Fox genes, FoxM, FoxN14 (jumeaux) and FoxN23 (Checkpoint suppressor like-1), Cyclins and CDKs in an onychophoran, a representative of a relatively small group of animals that are closely related to the arthropods. Expression of these genes is in the form of several waves that start as dot-like domains in the center of each segment and then transform into concentric rings that run towards the periphery of the segments. This oscillating gene expression, however, occurs exclusively along the anterior-posterior body axis in the tissue ventral to the base of the appendages, a region where the central nervous system and the enigmatic ventral and preventral organs of the onychophoran develop. We suggest that the oscillating gene expression and the resulting waves of expression we report are likely correlated with cell cycle control during the development of the onychophoran nervous system. This intriguing patterning appears to be unique for onychophorans as it is not found in any of the arthropods we also investigated in this study, and is likely correlated with the slow embryonic development of onychophorans compared to arthropods.

Mycoplasma synoviae induces serum amyloid A upregulation and promotes chicken synovial fibroblast cell proliferation

Mycoplasma synoviae (MS) infection causes infectious synovitis and arthritis with hyperplasia of synovial cells in the chicken joint. However, its mechanism is unknown. We used primary chicken synovial fibroblast (CSF) as the research object to study the role of MS in the proliferation of MS-infected CSF and determine the mechanisms involved. Using integrated transcriptomic and proteomic analyses of the interaction between CSF and MS, we screened a proliferation-regulated factor, serum amyloid A (SAA), that may regulate proliferation of MS-infected CSF. SAA appears to be associated with MS-induced CSF proliferation. To study the role of SAA in MS-induced CSF proliferation, a eukaryotic expression vector overexpressing SAA and a small interfering RNA (siRNA) targeting Saa were constructed to manipulate the expression of SAA. Cell proliferation and apoptosis were detected via cell counting kit-8 (CCK-8), 5-Ethynyl-2'-deoxyuridine (EdU), or terminal deoxyribonucleotidyl transferase-mediated dUTP nick-dnd labeling (TUNEL) assays, respectively. Western blot analysis was used to examine the protein expression level of SAA, cyclin E1, and cyclin-dependent kinase 2 (CDK2). In vitro, MS significantly promoted the proliferation of CSF and increased the production of SAA. Overexpression of SAA accelerated the proliferative ability of CSF, whereas knockdown of SAA depressed the proliferative ability of CSF. A TUNEL assay indicated that MS did not induce apoptosis. Silencing of SAA suppressed the expression of cyclin E1 and CDK2. These results suggest that MS may upregulate the expression of SAA, accelerate the cell cycle, and promote proliferation of CSF.

Clinical Candidates Targeting the ATR-CHK1-WEE1 Axis in Cancer

Selective killing of cancer cells while sparing healthy ones is the principle of the perfect cancer treatment and the primary aim of many oncologists, molecular biologists, and medicinal chemists. To achieve this goal, it is crucial to understand the molecular mechanisms that distinguish cancer cells from healthy ones. Accordingly, several clinical candidates that use particular mutations in cell-cycle progressions have been developed to kill cancer cells. As the majority of cancer cells have defects in G1 control, targeting the subsequent intra‑S or G2/M checkpoints has also been extensively pursued. This review focuses on clinical candidates that target the kinases involved in intra‑S and G2/M checkpoints, namely, ATR, CHK1, and WEE1 inhibitors. It provides insight into their current status and future perspectives for anticancer treatment. Overall, even though CHK1 inhibitors are still far from clinical establishment, promising accomplishments with ATR and WEE1 inhibitors in phase II trials present a positive outlook for patient survival.

Enhancing the chemosensitivity of HepG2 cells towards cisplatin by organoselenium pseudopeptides

Despite all recent advances in the treatment of hepatocellular carcinoma (HCC), chemotherapy resistance still represents a major challenge in its successful clinical management. Chemo-sensitization offers an attractive strategy to counter drug resistance. Herein we report the identification of novel organoselenium-based pseudopeptides as promising highly effective chemo-sensitizers in treating HCC with cisplatin. A series of functionalized pseudopeptide- (5-9 and 17-19), peptidomimetic- (10-12 and 20-23), and tetrazole-based (13-16 and 24-27) organoselenium compounds were synthesized via isonitrile-based multicomponent reactions from two novel selenium-containing isocyanides. All compounds were evaluated for their cytotoxicity against HepG2 and the non-cytotoxic doses were used to restor the sensitivity of the cells to cisplatin. New organoselenium compounds (7, 9, 15, or 23) led to an effective chemo-sensitization of HepG2 cells towards cisplatin (up-to 27-fold). Cell cycle studies indicate that the most potent peptidomimetic diselenide 23 arrested cells at the S phase and induced apoptosis via ROS modulation.

Nickel carcinogenesis mechanism: cell cycle dysregulation

Nickel (Ni) is a widely distributed metal in the environment and an important pollutant due to its widespread industrial applications. Ni has various toxicity in humans and experimental animals, including carcinogenicity. However, the carcinogenic effects of Ni remain troublesome. Cell cycle dysregulation may be an important carcinogenic mechanism and is also a potential molecular mechanism for Ni complexes anti-cancerous effects. Therefore, we conducted a literature review to summarize the effects of Ni on cell cycle. Up to now, there were three different reports on Ni-induced cell cycle arrest: (i) Ni can induce cell cycle arrest in G0/G1 phase, phosphorylation and degradation of IkappaB kinase-alpha (IKKα)-dependent cyclin D1 and phosphoinositide-3-kinase (PI3K)/serine-threonine kinase (Akt) pathway-mediated down-regulation of expressions of cyclin-dependent kinases 4 (CDK4) play important role in it; (ii) Ni can induce cell cycle arrest in S phase, but the molecular mechanism is not known; (iii) G2/M phase is the target of Ni toxicity, and Ni compounds cause G2/M cell cycle phase arrest by reducing cyclinB1/Cdc2 interaction through the activation of the ataxia telangiectasia mutated (ATM)-p53-p21 and ATM-checkpoint kinase inhibitor 1 (Chk1)/Chk2-cell division cycle 25 (Cdc25) pathways. Revealing the mechanisms of cell cycle dysregulation associated with Ni exposure may help in the prevention and treatment of Ni-related carcinogenicity and toxicology.

A Crosstalk Between Dual-Specific Phosphatases and Dual-Specific Protein Kinases Can Be A Potential Therapeutic Target for Anti-cancer Therapy

While protein tyrosine kinases (PTKs) play an initiative role in growth factor-mediated cellular processes, protein tyrosine phosphatases (PTPs) negatively regulates these processes, acting as tumor suppressors. Besides selective tyrosine dephosphorylation of PTKs via PTPs may affect oncogenic pathways during carcinogenesis. The PTP family contains a group of dual-specificity phosphatases (DUSPs) that regulate the activity of Mitogen-activated protein kinases (MAPKs), which are key effectors in the control of cell growth, proliferation and survival. Abnormal MAPK signaling is critical for initiation and progression stages of carcinogenesis. Since depletion of DUSP-MAPK phosphatases (MKPs) can reduce tumorigenicity, altering MAPK signaling by DUSP-MKP inhibitors could be a novel strategy in anti-cancer therapy. Moreover, Cdc25A is, a DUSP and a key regulator of the cell cycle, promotes cell cycle progression by dephosphorylating and activating cyclin-dependent kinases (CDK). Cdc25A-CDK pathway is a novel mechanism in carcinogenesis. Besides the mammalian target of rapamycin (mTOR) kinase inhibitors or mammalian target of rapamycin complex 1 (mTORC1) inhibition in combination with the dual phosphatidylinositol 3 kinase (PI3K)/mTOR or AKT kinase inhibitors are more effective in inhibiting the phosphorylation of eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1) and cap-dependent translation. Dual targeting of the Akt and mTOR signaling pathways regulates cellular growth, proliferation and survival. Like the Cdc2-like kinases (CLK), dual-specific tyrosine phosphorylation-regulated kinases (DYRKs) are essential for the regulation of cell fate. The crosstalk between dual-specific phosphatases and dual- specific protein kinases is a novel drug target for anti-cancer therapy. Therefore, the focus of this chapter involves protein kinase modules, critical biochemical checkpoints of cancer therapy and the synergistic effects of protein kinases and anti-cancer molecules.

Hepatoprotective effect of Xiayuxue decoction ethyl acetate fraction against carbon tetrachloride-induced liver fibrosis in mice via inducing apoptosis and suppressing activation of hepatic stellate cells

CONTEXT

Xiayuxue decoction (XYXD), a traditional Chinese medicine, is used for treating liver disease. However, the potential active constituents and mechanisms are still unclear.

OBJECTIVE

To explore the main active fraction extracts, active ingredients and possible mechanisms of XYXD for anti-hepatic fibrosis.

MATERIALS AND METHODS

Different fractions including ethyl acetate fraction (EF) were prepared from XYXD. These fractions, especially EF, were used to evaluate cell viability, proliferation, cell cycle, cytotoxicity and activation in hepatic stellate cells (HSCs). Liver fibrosis model was established by CCl₄ in C57BL/6 mice, and allocated to CCl₄ group, XYXD group and EF group with normal mice as control. Further, mitochondrial apoptosis-related proteins of HSCs, destruction and angiogenesis of liver sinusoidal endothelial cells (LSECs) and active ingredients of EF were evaluated.

RESULTS

The inhibition of proliferation, increase of S or/and G2/M phase population and suppression of α-SMA and COL-1 expression were obeserved in EF treated-JS1 and -LX2. Liver fibrosis-related indicators were improved by EF similar to XYXD in vivo. EF induced the apoptosis of HSCs in CCl₄-induced fibrosis, and inhibited the expression of HSCs apoptosis pathway-related proteins (JNK and p38-MAPKs), and LSECs destruction and angiogenesis. Multiple ingredients (emodin, rhein, aloe-emodin, prunasin) in EF have shown inhibited the activation of JS1.

DISCUSSION AND CONCLUSION

EF was the main active fraction extracts of XYXD, and the underlying mechanisms might relate to induction of HSCs apoptosis. Emodin, rhein, aloe-emodin and prunasin were main active ingredients of EF, which provides a potential drug for the treatment of liver fibrosis.

Rck of Salmonella Typhimurium Delays the Host Cell Cycle to Facilitate Bacterial Invasion

Salmonella Typhimurium expresses on its outer membrane the protein Rck which interacts with the epidermal growth factor receptor (EGFR) of the plasma membrane of the targeted host cells. This interaction activates signaling pathways, leading to the internalization of Salmonella. Since EGFR plays a key role in cell proliferation, we sought to determine the influence of Rck mediated infection on the host cell cycle. By analyzing the DNA content of uninfected and infected cells using flow cytometry, we showed that the Rck-mediated infection induced a delay in the S-phase (DNA replication phase) of the host cell cycle, independently of bacterial internalization. We also established that this Rck-dependent delay in cell cycle progression was accompanied by an increased level of host DNA double strand breaks and activation of the DNA damage response. Finally, we demonstrated that the S-phase environment facilitated Rck-mediated bacterial internalization. Consequently, our results suggest that Rck can be considered as a cyclomodulin with a genotoxic activity.

The interactome of Singapore grouper iridovirus protein ICP18 as revealed by proximity-dependent BioID approach

Singapore grouper iridovirus (SGIV) is a large double-stranded DNA virus that is a major threat to grouper aquaculture. The pathogenesis of SGIV is not well understood so far. Previous studies have revealed that ICP18, an immediate early protein encoded by SGIV ORF086R gene, promotes viral replication by regulating cell proliferation and virus assembly. In the present study, the potential functions of ICP18 were further explored by probing into its interactors using a proximity-dependent BioID method. Since our in-house grouper embryonic cells (a natural host cell of SGIV) could not be efficiently transfected with the plasmid DNA, and the grouper genome data for mass spectrometry-based protein identification is not currently available, we chosen a non-permissive cell (HEK293 T) as a substitute for this study. A total of 112 cellular proteins that potentially bind to ICP18 were identified by mass spectrometry analysis. Homology analysis showed that among these identified proteins, 110 candidate ICP18-interactors had homologous proteins in zebrafish (a host of SGIV), and shared high sequence identity. Further analysis revealed that the identified ICP18-interacting proteins modulate various cellular processes such as cell cycle and cell adhesion. In addition, the interaction between ICP18 and its candidate interactor, i.e., cyclin-dependent kinase1 (CDK1), was confirmed using Co-immunoprecipitation (Co-IP) and Pull-down assays. Collectively, our present data provides additional insight into the biological functions of ICP18 during viral infection, which could help in further unraveling the pathogenesis of SGIV.

FBXO2 Promotes Proliferation of Endometrial Cancer by Ubiquitin-Mediated Degradation of FBN1 in the Regulation of the Cell Cycle and the Autophagy Pathway

F-box proteins, as substrates for S phase kinase-associated protein 1 (SKP1)-cullin 1 (CUL1)-F-box protein (SCF) ubiquitin ligase complexes, mediate the degradation of a large number of regulatory proteins involved in cancer processes. In this study, we found that F-box only protein 2 (FBXO2) was up-regulated in 21 endometrial carcinoma (EC) samples compared with five normal endometrium samples based on our Fudan cohort RNA-sequencing. The increased FBXO2 expression was associated with tumor stage, tumor grade, and histologic tumor type, and poor prognosis based on The Cancer Genome Atlas (TCGA) database. FBXO2 knockdown inhibited EC cell proliferation, and FBXO2 overexpression promoted the parental cell phenotype in vivo and in vitro. Fibrillin1 (FBN1) was also identified as a substrate for FBXO2 using a ubiquitination-proteome approach. In addition, promotion of EC proliferation by FBXO2 was regulated by specific proteins of the cell cycle (CDK4, CyclinD1, CyclinD2, and CyclinA1) and the autophagy signaling pathway (ATG4A and ATG4D) based on RNA sequencing (RNA-seq). We concluded that FBXO2 acts as an E3 ligase that targets FBN1 for ubiquitin-dependent degradation, so as to promote EC proliferation by regulating the cell cycle and the autophagy signaling pathway. Targeting FBXO2 may represent a potential therapeutic target for EC.

Synthetic lethality strategies: Beyond BRCA1/2 mutations in pancreatic cancer

Cancer cells are often characterized by abnormalities in DNA damage response including defects in cell cycle checkpoints and/or DNA repair. Synthetic lethality between DNA damage repair (DDR) pathways has provided a paradigm for cancer therapy by targeting DDR. The successful example is that cancer cells with BRCA1/2 mutations are sensitized to poly(adenosine diphosphate [ADP]-ribose)polymerase (PARP) inhibitors. Beyond the narrow scope of defects in the BRCA pathway, "BRCAness" provides more opportunities for synthetic lethality strategy. In human pancreatic cancer, frequent mutations were found in cell cycle and DDR genes, including P16, P73, APC, MLH1, ATM, PALB2, and MGMT. Combined DDR inhibitors and chemotherapeutic agents are under preclinical or clinical trials. Promoter region methylation was found frequently in cell cycle and DDR genes. Epigenetics joins the Knudson's "hit" theory and "BRCAness." Aberrant epigenetic changes in cell cycle or DDR regulators may serve as a new avenue for synthetic lethality strategy in pancreatic cancer.

β-Carbolines in Experiments on Laboratory Animals

Some studies have ascribed a protective effect against neurodegenerative diseases to the β-carbolines harman (H) and norharman (NH), which occur mostly in coffee and coffee substitutes. We determined the concentrations of β-carbolines and undesirable compounds (such as acrylamide) in roasted coffee substitute ingredients and found that chicory coffee was optimal. Two in vivo experiments were conducted with seventeen-month-old male Sprague Dawley rats fed a diet with the addition of pure carboline standards in the first stage, and chicory in the second. We observed an increase in the level of H and NH in blood plasma, as well as higher activity of animals in the battery behavioral test, particularly in the second stage. The results of in vitro studies-particularly the level of the expression in brain tissue of genes associated with aging processes and neurodegenerative diseases-clearly show the benefits of a diet rich in β-carbolines.

Aurora kinases and DNA damage response

It is well established that Aurora kinases perform critical functions during mitosis. It has become increasingly clear that the Aurora kinases also perform a myriad of non-mitotic functions including DNA damage response. The available evidence indicates that inhibition Aurora kinase A (AURKA) may contribute to the G₂ DNA damage checkpoint through AURKA's functions in PLK1 and CDC25B activation. Both AURKA and Aurora kinase B (AURKB) are also essential in mitotic DNA damage response that guard against DNA damage-induced chromosome segregation errors, including the control of abscission checkpoint and prevention of micronuclei formation. Dysregulation of Aurora kinases can trigger DNA damage in mitosis that is sensed in the subsequent G₁ by a p53-dependent postmitotic checkpoint. Aurora kinases are themselves linked to the G₁ DNA damage checkpoint through p53 and p73 pathways. Finally, several lines of evidence provide a connection between Aurora kinases and DNA repair and apoptotic pathways. Although more studies are required to provide a comprehensive picture of how cells respond to DNA damage, these findings indicate that both AURKA and AURKB are inextricably linked to pathways guarding against DNA damage. They also provide a rationale to support more detailed studies on the synergism between small-molecule inhibitors against Aurora kinases and DNA-damaging agents in cancer therapies.

Identification of Hub Genes as Biomarkers Correlated with the Proliferation and Prognosis in Lung Cancer: A Weighted Gene Co-Expression Network Analysis

Lung cancer is one of the most malignant tumors in the world. Early diagnosis and treatment of lung cancer are vitally important to reduce the mortality of lung cancer patients. In the present study, we attempt to identify the candidate biomarkers for lung cancer by weighted gene co-expression network analysis (WGCNA). Gene expression profile of GSE30219 was downloaded from the gene expression omnibus (GEO) database. The differentially expressed genes (DEGs) were analyzed by the limma package, and the co-expression modules of genes were built by WGCNA. UALCAN was used to analyze the relative expression of normal group and tumor subgroups based on tumor individual cancer stages. Survival analysis for the hub genes was performed by Kaplan–Meier plotter analysis with the TCGA database. A total of 2176 genes (745 upregulated and 1431 downregulated genes) were obtained from the GSE30219 database. Seven gene co-expression modules were conducted by WGCNA and the blue module might be inferred as the most crucial module in the pathogenesis of lung cancer. In the pathway enrichment analysis of KEGG, the candidate genes were enriched in the “DNA replication,” “Cell cycle,” and “P53 signaling pathway” pathways. Among these, the cell cycle pathway was the most significant pathway in the blue module with four hub genes CCNB1, CCNE2, MCM7, and PCNA which were selected in our study. Kaplan–Meier plotter analysis indicated that the high expressions of four hub genes were correlated with a worse overall survival (OS) and advanced tumors. qRT-PCR showed that mRNA expression levels of MCM7 (p = 0.038) and CCNE2 (0.003) were significantly higher in patients with the TNM stage. In summary, the high expression of the MCM7 and CCNE2 were significantly related with advanced tumors and worse OS in lung cancer. Thus, the MCM7 and CCNE2 genes can be good indicators for cellular proliferation and prognosis in lung cancer.

Prenatal Exposure to Gossypol Impairs Corticogenesis of Mouse

Gossypol is a yellow polyphenolic compounds extracted from roots, stems and seeds of cotton plants. Excessive intake of gossypol induces severe pathological signs of toxicity in livestock and wildlife. Currently, gossypol has received widespread attention for its toxic effects on the reproductive system. However, reports of the effects of gossypol during corticogenesis and the development of the mouse cerebral cortex are unavailable. In the present study, gossypol was orally administrated at a dose of 0, 20, and 50 mg/kg body weight/day to pregnant mice from embryonic day 6.5 to the time of sample collection. We used in utero electroporation and immunofluorescence to demonstrate that gossypol impaired cortical neuronal migration. Furthermore, labeling with 5-bromo-2-deoxyuridine and western blot analysis revealed that gossypol disturbed the balance between proliferation and differentiation of neural progenitors, inhibited neural progenitor cell proliferation, neuronal differentiation, and maturation. Additionally, cortical progenitor apoptotic cell death increased in the developing gossypol-treated cortex, which was associated with NF-κB and MAPK pathways. In conclusion, our findings indicate that gossypol exposure disrupted neurogenesis in the developing neocortex, suggesting the potentially harmful impact of gossypol on the cerebral cortex development of humans and livestock.

UbcH10 a Major Actor in Cancerogenesis and a Potential Tool for Diagnosis and Therapy

Malignant transformation is a multistep process in which several molecular entities become dysregulated and result in dysfunction in the regulation of cell proliferation. In past years, scientists have gradually dissected the pathways involved in the regulation of the cell cycle. The mitotic ubiquitin-conjugating enzymes UbcH10, has been extensively studied since its cloning and characterization and it has been identified as a constantly overexpressed factor in many types of cancer. In this paper, we have reviewed the literature about UbcH10 in human cancer, pointing out the association between its overexpression and exacerbation of cancer phenotype. Moreover, many recalled studied demonstrated how immunohistochemistry or RT-PCR analysis can distinguish normal tissues and benign lesions from malignant neoplasms. In other experimental studies, many of the consequences of UbcH10 overexpression, such as increased proliferation, metastasizing, cancer progression and resistance to anticancer drugs are reversed through gene silencing techniques. In recent years, many authors have defined UbcH10 evaluation in cancer patients as a useful tool for diagnosis and therapy. This opinion is shared by the authors who advertise how it would be useful to start using in clinical practice the notions acquired about this important moleculein the carcinogenesis of many human malignancies.

An appreciation of the prescience of Don Gilbert (1930-2011): master of the theory and experimental unravelling of biochemical and cellular oscillatory dynamics

We review Don Gilbert's pioneering seminal contributions that both detailed the mathematical principles and the experimental demonstration of several of the key dynamic characteristics of life. Long before it became evident to the wider biochemical community, Gilbert proposed that cellular growth and replication necessitate autodynamic occurrence of cycles of oscillations that initiate, coordinate and terminate the processes of growth, during which all components are duplicated and become spatially re-organised in the progeny. Initiation and suppression of replication exhibit switch-like characteristics, that is, bifurcations in the values of parameters that separate static and autodynamic behaviour. His limit cycle solutions present models developed in a series of papers reported between 1974 and 1984, and these showed that most or even all of the major facets of the cell division cycle could be accommodated. That the cell division cycle may be timed by a multiple of shorter period (ultradian) rhythms, gave further credence to the central importance of oscillatory phenomena and homeodynamics as evident on multiple time scales (seconds to hours). Further application of the concepts inherent in limit cycle operation as hypothesised by Gilbert more than 50 years ago are now validated as being applicable to oscillatory transcript, metabolite and enzyme levels, cellular differentiation, senescence, cancerous states and cell death. Now, we reiterate especially for students and young colleagues, that these early achievements were even more exceptional, as his own lifetime's work on modelling was continued with experimental work in parallel with his predictions of the major current enterprises of biological research.