The role of Anaphase Promoting Complex activation, inhibition and substrates in cancer development and progression

Activation of the Anaphase Promoting Complex Restores Impaired Mitotic Progression and Chemosensitivity in Multiple Drug-Resistant Human Breast Cancer

The development of multiple-drug-resistant (MDR) cancer all too often signals the need for toxic alternative therapy or palliative care. Our recent in vivo and in vitro studies using canine MDR lymphoma cancer cells demonstrate that the Anaphase Promoting Complex (APC) is impaired in MDR cells compared to normal canine control and drug-sensitive cancer cells. Here, we sought to establish whether this phenomena is a generalizable mechanism independent of species, malignancy type, or chemotherapy regime. To test the association of blunted APC activity with MDR cancer behavior, we used matched parental and MDR MCF7 human breast cancer cells, and a patient-derived xenograft (PDX) model of human triple-negative breast cancer. We show that APC activating mechanisms, such as APC subunit 1 (APC1) phosphorylation and CDC27/CDC20 protein associations, are reduced in MCF7 MDR cells when compared to chemo-sensitive matched cell lines. Consistent with impaired APC function in MDR cells, APC substrate proteins failed to be effectively degraded. Similar to our previous observations in canine MDR lymphoma cells, chemical activation of the APC using Mad2 Inhibitor-1 (M2I-1) in MCF7 MDR cells enhanced APC substrate degradation and resensitized MDR cells in vitro to the cytotoxic effects of the alkylating chemotherapeutic agent, doxorubicin (DOX). Using cell cycle arrest/release experiments, we show that mitosis is delayed in MDR cells with elevated substrate levels. When pretreated with M2I-1, MDR cells progress through mitosis at a faster rate that coincides with reduced levels of APC substrates. In our PDX model, mice growing a clinically MDR human triple-negative breast cancer tumor show significantly reduced tumor growth when treated with M2I-1, with evidence of increased DNA damage and apoptosis. Thus, our results strongly support the hypothesis that APC impairment is a driver of aggressive tumor development and that targeting the APC for activation has the potential for meaningful clinical benefits in treating recurrent cases of MDR malignancy.

The molecular circadian rhythms regulating the cell cycle

The circadian clock controls the expression of a large proportion of protein-coding genes in mammals and can modulate a wide range of physiological processes. Recent studies have demonstrated that disruption or dysregulation of the circadian clock is involved in the development and progression of several diseases, including cancer. The cell cycle is considered to be the fundamental process related to cancer. Accumulating evidence suggests that the circadian clock can control the expression of a large number of genes related to the cell cycle. This article reviews the mechanism of cell cycle-related genes whose chromatin regulatory elements are rhythmically occupied by core circadian clock transcription factors, while their RNAs are rhythmically expressed. This article further reviews the identified oscillatory cell cycle-related genes in higher organisms such as baboons and humans. The potential functions of these identified genes in regulating cell cycle progression are also discussed. Understanding how the molecular clock controls the expression of cell cycle genes will be beneficial for combating and treating cancer.

Inhibitors Targeting the F-BOX Proteins

F-box proteins are involved in multiple cellular processes through ubiquitylation and consequent degradation of targeted substrates. Any significant mutation in F-box protein-mediated proteolysis can cause human malformations. The various cellular processes F-box proteins involved include cell proliferation, apoptosis, invasion, angiogenesis, and metastasis. To target F-box proteins and their associated signaling pathways for cancer treatment, researchers have developed thousands of F-box inhibitors. The most advanced inhibitor of FBW7, NVD-BK M120, is a powerful P13 kinase inhibitor that has been proven to bring about apoptosis in cancerous human lung cells by disrupting levels of the protein known as MCL1. Moreover, F-box Inhibitors have demonstrated their efficacy for treating certain cancers through targeting particular mutated proteins. This paper explores the key studies on how F-box proteins act and their contribution to malignancy development, which fabricates an in-depth perception of inhibitors targeting the F-box proteins and their signaling pathways that eventually isolate the most promising approach to anti-cancer treatments.

Enkurin: a novel marker for myeloproliferative neoplasms from platelet, megakaryocyte, and whole blood specimens

Impaired protein homeostasis, though well established in age-related disorders, has been recently linked with the pathogenesis of myeloproliferative neoplasms (MPNs). However, little is known about MPN-specific modulators of proteostasis, thus impeding our ability for increased mechanistic understanding and discovery of additional therapeutic targets. Loss of proteostasis, in itself, is traced to dysregulated mechanisms in protein folding and intracellular calcium signaling at the endoplasmic reticulum (ER). Here, using ex vivo and in vitro systems (including CD34+ cultures from patient bone marrow and healthy cord/peripheral blood specimens), we extend our prior data from platelet RNA sequencing in patients with MPN and discover select proteostasis-associated markers at RNA and/or protein levels in each of platelet, parent megakaryocyte, and whole blood specimens. Importantly, we identify a novel role in MPNs for enkurin (ENKUR), a calcium mediator protein originally implicated only in spermatogenesis. Our data reveal consistent ENKUR downregulation at both RNA and protein levels across specimens from patients with MPN and experimental models (including upon treatment with thapsigargin, an agent that causes protein misfolding in the ER by selective loss of calcium), with a concomitant upregulation of a cell cycle marker, CDC20. Silencing of ENKUR using short hairpin RNA in CD34+-derived megakaryocytes further confirms this association with CDC20 at both RNA and protein levels and indicates a likely role for the PI3K/Akt pathway. Together, our work sheds light on enkurin as a novel marker of MPN pathogenesis and indicates further mechanistic investigation into a role for dysregulated calcium homeostasis and ER and protein folding stress in MPN transformation.

Robust Identification of Differential Gene Expression Patterns from Multiple Transcriptomics Datasets for Early Diagnosis, Prognosis, and Therapies for Breast Cancer

Background and Objectives: Breast cancer (BC) is one of the major causes of cancer-related death in women globally. Proper identification of BC-causing hub genes (HubGs) for prognosis, diagnosis, and therapies at an earlier stage may reduce such death rates. However, most of the previous studies detected HubGs through non-robust statistical approaches that are sensitive to outlying observations. Therefore, the main objectives of this study were to explore BC-causing potential HubGs from robustness viewpoints, highlighting their early prognostic, diagnostic, and therapeutic performance. Materials and Methods: Integrated robust statistics and bioinformatics methods and databases were used to obtain the required results. Results: We robustly identified 46 common differentially expressed genes (cDEGs) between BC and control samples from three microarrays (GSE26910, GSE42568, and GSE65194) and one scRNA-seq (GSE235168) dataset. Then, we identified eight cDEGs (COL11A1, COL10A1, CD36, ACACB, CD24, PLK1, UBE2C, and PDK4) as the BC-causing HubGs by the protein-protein interaction (PPI) network analysis of cDEGs. The performance of BC and survival probability prediction models with the expressions of HubGs from two independent datasets (GSE45827 and GSE54002) and the TCGA (The Cancer Genome Atlas) database showed that our proposed HubGs might be considered as diagnostic and prognostic biomarkers, where two genes, COL11A1 and CD24, exhibit better performance. The expression analysis of HubGs by Box plots with the TCGA database in different stages of BC progression indicated their early diagnosis and prognosis ability. The HubGs set enrichment analysis with GO (Gene ontology) terms and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways disclosed some BC-causing biological processes, molecular functions, and pathways. Finally, we suggested the top-ranked six drug molecules (Suramin, Rifaximin, Telmisartan, Tukysa Tucatinib, Lynparza Olaparib, and TG.02) for the treatment of BC by molecular docking analysis with the proposed HubGs-mediated receptors. Molecular docking analysis results also showed that these drug molecules may inhibit cancer-related post-translational modification (PTM) sites (Succinylation, phosphorylation, and ubiquitination) of hub proteins. Conclusions: This study's findings might be valuable resources for diagnosis, prognosis, and therapies at an earlier stage of BC.

CDC23 knockdown suppresses the proliferation, migration and invasion of liver cancer via the EMT process

Liver cancer (LC) is a malignant tumour that is associated with high mortality rates worldwide. Cell division cycle 23 (CDC23) acts as an oncogene in papillary thyroid cancer. In addition, epithelial-mesenchymal transition (EMT) is frequently involved in the malignant metastasis of various cancer types. Therefore, we hypothesized that CDC23 may regulate the malignant biological behaviours of LC cells through EMT. Proliferation, colony formation and Transwell assays, western blotting and xenograft experiments were performed. The results of the present study showed that CDC23 was highly expressed in LC cell lines. In addition, it was found via multiple in vitro assays that CDC23 knockdown reduced the proliferation, migration and invasion of LC cell lines. Finally, an in vivo study confirmed that CDC23 knockdown inhibited the growth of xenograft LC in nude mice. More importantly, the changes in the levels of EMT-related marker proteins were analysed in the sh-CDC23 group compared with the sh-NC group of cells and xenografts. E-cadherin was upregulated, and N-cadherin and vimentin were significantly downregulated after CDC23 silencing. Taken together, these results revealed that the knockdown of CDC23 inhibits the progression of LC by regulating EMT and that CDC23 may be a novel therapeutic target for LC.

CEBP-β and PLK1 as Potential Mediators of the Breast Cancer/Obesity Crosstalk: In Vitro and In Silico Analyses

Over the last two decades, obesity has reached pandemic proportions in several countries, and expanding evidence is showing its contribution to several types of malignancies, including breast cancer (BC). The conditioned medium (CM) from mature adipocytes contains a complex of secretes that may mimic the obesity condition in studies on BC cell lines conducted in vitro. Here, we report a transcriptomic analysis on MCF-7 BC cells exposed to adipocyte-derived CM and focus on the predictive functional relevance that CM-affected pathways/processes and related biomarkers (BMs) may have in BC response to obesity. CM was demonstrated to increase cell proliferation, motility and invasion as well as broadly alter the transcript profiles of MCF-7 cells by significantly modulating 364 genes. Bioinformatic functional analyses unraveled the presence of five highly relevant central hubs in the direct interaction networks (DIN), and Kaplan-Meier analysis sorted the CCAAT/enhancer binding protein beta (CEBP-β) and serine/threonine-protein kinase PLK1 (PLK1) as clinically significant biomarkers in BC. Indeed, CEBP-β and PLK1 negatively correlated with BC overall survival and were up-regulated by adipocyte-derived CM. In addition to their known involvement in cell proliferation and tumor progression, our work suggests them as a possible "deus ex machina" in BC response to fat tissue humoral products in obese women.

Ubiquitin Proteasome Gene Signatures in Ependymoma Molecular Subtypes

The ubiquitin proteasome system (UPS) is critically important for cellular homeostasis and affects virtually all key functions in normal and neoplastic cells. Currently, a comprehensive review of the role of the UPS in ependymoma (EPN) brain tumors is lacking but may provide valuable new information on cellular networks specific to different EPN subtypes and reveal future therapeutic targets. We have reviewed publicly available EPN gene transcription datasets encoding components of the UPS pathway. Reactome analysis of these data revealed genes and pathways that were able to distinguish different EPN subtypes with high significance. We identified differential transcription of several genes encoding ubiquitin E2 conjugases associated with EPN subtypes. The expression of the E2 conjugase genes UBE2C, UBE2S, and UBE2I was elevated in the ST_EPN_RELA subtype. The UBE2C and UBE2S enzymes are associated with the ubiquitin ligase anaphase promoting complex (APC/c), which regulates the degradation of substrates associated with cell cycle progression, whereas UBE2I is a Sumo-conjugating enzyme. Additionally, elevated in ST_EPN_RELA were genes for the E3 ligase and histone deacetylase HDAC4 and the F-box cullin ring ligase adaptor FBX031. Cluster analysis demonstrated several genes encoding E3 ligases and their substrate adaptors as EPN subtype specific genetic markers. The most significant Reactome Pathways associated with differentially expressed genes for E3 ligases and their adaptors included antigen presentation, neddylation, sumoylation, and the APC/c complex. Our analysis provides several UPS associated factors that may be attractive markers and future therapeutic targets for the subtype-specific treatment of EPN patients.

Integrative bioinformatics analysis to identify the effects of circadian rhythm on Crohn’s disease

Background: Crohn’s disease (CD) is a multifactorial inflammatory bowel disease characterized by complex aberrant autoimmune disorders. Currently, the involvement of the circadian rhythm in the pathogenesis of CD is unknown.

Methods: Bulk and single-cell RNA-seq data and associated clinical data from patients with CD were downloaded from the Gene Expression Omnibus (GEO). Single-sample gene set enrichment analysis was performed to calculate the enrichment score (ES) of circadian rhythm-related genes. Differential expression analysis was used to identify differentially expressed genes. Functional enrichment analysis was used to explore potential disease mechanisms. CIBERSORT was used to estimate immune cell abundance. Single-cell RNA-seq data were analyzed using the R package “Seurat.”

Results: The ES of circadian rhythm-related genes was lower in the CD tissue than in the normal tissue. Ubiquitin-specific protease 2 (USP2), a circadian rhythm-related gene, was identified as a potential modulator of CD pathogenesis. USP2 expression was reduced in CD and was associated with disease severity. Moreover, the analysis of bulk RNA-seq and single-cell RNA-seq data showed that monocyte and neutrophil abundance was elevated in CD and was negatively correlated with USP2 expression. It should be noted that USP2 expression in acinar cells was negatively correlated with monocyte and neutrophil abundance. Functional enrichment analysis revealed several canonical pathways to be enriched in CD, including the interleukin-17 signaling pathway, tumor necrosis factor signaling pathway, cytokine–cytokine receptor interaction, toll-like receptor signaling pathway, and nod-like receptor signaling pathway.

Conclusion: Aberrant expression of circadian rhythm-related genes is correlated with CD pathogenesis. USP2 might be related to crosstalk among the different cell types in CD. These findings provide insights into future chronotherapy for CD.

Activation of the Anaphase Promoting Complex Reverses Multiple Drug Resistant Cancer in a Canine Model of Multiple Drug Resistant Lymphoma

Simple Summary

Multiple drug resistant cancers develop all too soon in patients who received successful cancer treatment. A lack of treatment options often leaves palliative care as the last resort. We tested whether the insulin sensitizer, metformin, known to have anti-cancer activity, could impact canines with drug resistant lymphoma when added to chemotherapy. All canines in the study expressed protein markers of drug resistance and within weeks of receiving metformin, the markers were decreased. A microarray was performed, and from four canines assessed, a common set of 290 elevated genes were discovered in tumor cells compared to control cells. This cluster was enriched with genes that stall the cell cycle, with a large component representing substrates of the Anaphase Promoting Complex (APC), which degrades proteins. One canine entered partial remission. RNAs from this canine showed that APC substrates were decreased during remission and elevated again during relapse, suggesting that the APC was impaired in drug resistant canines and restored when remission occurred. We validated our results in cell lines using APC inhibitors and activators. We conclude that the APC may be a vital guardian of the genome and could delay the onset of multiple drug resistance when activated.

Abstract

Like humans, canine lymphomas are treated by chemotherapy cocktails and frequently develop multiple drug resistance (MDR). Their shortened clinical timelines and tumor accessibility make canines excellent models to study MDR mechanisms. Insulin-sensitizers have been shown to reduce the incidence of cancer in humans prescribed them, and we previously demonstrated that they also reverse and delay MDR development in vitro. Here, we treated canines with MDR lymphoma with metformin to assess clinical and tumoral responses, including changes in MDR biomarkers, and used mRNA microarrays to determine differential gene expression. Metformin reduced MDR protein markers in all canines in the study. Microarrays performed on mRNAs gathered through longitudinal tumor sampling identified a 290 gene set that was enriched in Anaphase Promoting Complex (APC) substrates and additional mRNAs associated with slowed mitotic progression in MDR samples compared to skin controls. mRNAs from a canine that went into remission showed that APC substrate mRNAs were decreased, indicating that the APC was activated during remission. In vitro validation using canine lymphoma cells selected for resistance to chemotherapeutic drugs confirmed that APC activation restored MDR chemosensitivity, and that APC activity was reduced in MDR cells. This supports the idea that rapidly pushing MDR cells that harbor high loads of chromosome instability through mitosis, by activating the APC, contributes to improved survival and disease-free duration.

Transcription of the Envelope Protein by 1-L Protein–RNA Recognition Code Leads to Genes/Proteins That Are Relevant to the SARS-CoV-2 Life Cycle and Pathogenesis

The theoretical protein–RNA recognition code was used in this study to research the compatibility of the SARS-CoV-2 envelope protein (E) with mRNAs in the human transcriptome. According to a review of the literature, the spectrum of identified genes showed that the virus post-transcriptionally promotes or represses the genes involved in the SARS-CoV-2 life cycle. The identified genes/proteins are also involved in adaptive immunity, in the function of the cilia and wound healing (EMT and MET) in the pulmonary epithelial tissue, in Alzheimer’s and Parkinson’s disease and in type 2 diabetes. For example, the E-protein promotes BHLHE40, which switches off the IL-10 inflammatory “brake” and inhibits antiviral T_Hαβ cells. In the viral cycle, E supports the COPII-SCAP-SREBP-HSP90α transport complex by the lowering of cholesterol in the ER and by the repression of insulin signaling, which explains the positive effect of HSP90 inhibitors in COVID-19 (geldanamycin), and E also supports importin α/β-mediated transport to the nucleus, which explains the positive effect of ivermectin, a blocker of importins α/β. In summary, transcription of the envelope protein by the 1-L protein–RNA recognition code leads to genes/proteins that are relevant to the SARS-CoV-2 life cycle and pathogenesis.

microRNA-1321 and microRNA-7515 contribute to the progression of non-small cell lung cancer by targeting CDC20

Cell division cycle 20 (CDC20) and microRNAs (miRNAs) are differentially expressed in non-small cell lung cancer (NSCLC). The current study aimed to investigate the role of miR-1321 and miR-7515 regulation in CDC20 during NSCLC development. CDC20 expression in paracancerous and tumor tissues was assessed using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The relationship between CDC20 expression and prognosis of patients was analyzed using the TCGA database. The expression profile of CDC20 in healthy lung cells and NSCLC cells was detected using qRT-PCR and western blotting. After the knockdown of CDC20 in NSCLC cells, the cell proliferation, apoptosis, migration, invasion, and cell cycle changes were investigated by CCK8, EdU, flow cytometry, wound healing, and Transwell assays. The miRNAs targeting CDC20 were predicted using two bioinformatics websites and validated using dual-luciferase assays. CDC20 was enhanced in NSCLC tissues and cells, thus predicting the poor prognosis in NSCLC patients. After CDC20 inhibition, the malignant phenotype of NSCLC cells was reverted. miR-1321 and miR-7515 targeted CDC20 and exhibited the same anti-tumor effects as CDC20 silencing. Functional rescue experiments showed that CDC20 overexpression averted the anti-tumor effects of miR-1321 and miR-7515 on NSCLC cells. miR-1321 and miR-7515 inhibited NSCLC development by targeting CDC20. Thus, the current study has implications in NSCLC treatment and provides novel insights into NSCLC management.

A high-quality chromosome-level genome of the endangered roughskin sculpin provides insights into its evolution and adaptation

The cottids (Cottidae) are a taxonomically diverse and ecologically important component of many marine and freshwater ecosystems. Despite recent breakthroughs in long-read sequencing, high quality genomic resources are still limited for studies of ecological and evolutionary processes in cottids. Here we generated a high-quality, chromosome-scale genome assembly (521.26 Mb) of the catadromous roughskin sculpin (Trachidermus fasciatus Heckel) with a contig N50 of 2.93 Mb and a scaffold N50 of 24.06 Mb. Approximately 21.97% of the genome was composed of repetitive elements. A total of 21,872 protein-coding genes were predicted, of which 19,900 genes (90.98%) were functionally annotated. Phylogenetic analysis supported the validity of Scorpaenoidei and Cottioidei as two suborders of the Perciformes. Chromosome-scale collinearity analyses identified four chromosome fusions leading to the reduction of chromosome number in T. fasciatus. Gene families related to cell apoptosis and cell death were expanded and those related to immune system were contracted, suggesting that these gene families might be relevant to a host of phenotypic differences between T. fasciatus and other teleosts. Gene families associated with osmoregulation were also expanded, which might be associated with its catadromous life history. A total of 50 aging-associated genes were found to be under positive selection, which might be associated with the short lifespan of T. fasciatus. The high-quality genome assembly and annotation will promote researches into the evolution of catadromous life history and short lifespan for T. fasciatus and facilitate comparative genomic studies of cottids in the near future.

Varying outcomes of triple-negative breast cancer in different age groups-prognostic value of clinical features and proliferation

PURPOSE

Triple-negative breast cancer (TNBC) is an aggressive disease lacking specific biomarkers to guide treatment decisions. We evaluated the combined prognostic impact of clinical features and novel biomarkers of cell cycle-progression in age-dependent subgroups of TNBC patients.

METHODS

One hundred forty seven TNBC patients with complete clinical data and up to 18 year follow-up were collected from Turku University Hospital, Finland. Eight biomarkers for cell division were immunohistochemically detected to evaluate their clinical applicability in relation to patient and tumor characteristics.

RESULTS

Age at diagnosis was the decisive factor predicting disease-specific mortality in TNBC (p = 0.002). The established prognostic features, nodal status and Ki-67, predicted survival only when combined with age. The outcome and prognostic features differed significantly between age groups, middle-aged patients showing the most favorable outcome. Among young patients, only lack of basal differentiation predicted disease outcome, indicating 4.5-fold mortality risk (p = 0.03). Among patients aged > 57, the established prognostic features predicted disease outcome with up to 3.0-fold mortality risk for tumor size ≥ 2 cm (p = 0.001). Concerning cell proliferation, Ki-67 alone was a significant prognosticator among patients aged > 57 years (p = 0.009). Among the studied cell cycle-specific biomarkers, only geminin predicted disease outcome, indicating up to 6.2-fold increased risk of mortality for tumor size < 2 cm (p = 0.03).

CONCLUSION

Traditional clinical features do not provide optimal prognostic characterization for all TNBC patients. Young age should be considered as an additional adverse prognostic feature in therapeutic considerations. Increased proliferation, as evaluated using Ki-67 or geminin immunohistochemistry, showed potential in detecting survival differences in subgroups of TNBC.

Potential Therapeutic and Prognostic Values of LSM Family Genes in Breast Cancer

In recent decades, breast cancer (BRCA) has become one of the most common diseases worldwide. Understanding crucial genes and their signaling pathways remain an enormous challenge in evaluating the prognosis and possible therapeutics. The "Like-Smith" (LSM) family is known as protein-coding genes, and its member play pivotal roles in the progression of several malignancies, although their roles in BRCA are less clear. To discover biological processes associated with LSM family genes in BRCA development, high-throughput techniques were applied to clarify expression levels of LSMs in The Cancer Genome Atlas (TCGA)-BRCA dataset, which was integrated with the cBioPortal database. Furthermore, we investigated prognostic values of LSM family genes in BCRA patients using the Kaplan-Meier database. Among genes of this family, LSM4 expression levels were highly associated with poor prognostic outcomes with a hazard ratio of 1.35 (95% confidence interval 1.21-1.51, p for trend = 3.4 × 10-7). MetaCore and GlueGo analyses were also conducted to examine transcript expression signatures of LSM family members and their coexpressed genes, together with their associated signaling pathways, such as "Cell cycle role of APC in cell cycle regulation" and "Immune response IL-15 signaling via MAPK and PI3K cascade" in BRCA. Results showed that LSM family members, specifically LSM4, were significantly correlated with oncogenesis in BRCA patients. In summary, our results suggested that LSM4 could be a prospective prognosticator of BRCA.

Genomic instability in lower-grade glioma: Prediction of prognosis based on lncRNA and immune infiltration

Glioma is the most common type of primary malignant tumor in the central nervous system. Tumor recurrence and progression are common in lower-grade glioma (LGG). Immune checkpoint blockade (ICB), as an emerging immunotherapy, is expected to improve the prognosis of patients undergoing conventional treatment, but it currently performs poorly in glioma. We divided patients into genome-stable and -unstable groups according to the somatic mutation count and then found that the expression of CDC20 was positively correlated with genomic instability. We compared the differences in long non-coding RNA (lncRNA) expression and immune infiltration between the two groups. Five lncRNAs and three immune cell types were identified to construct risk models and a nomogram combing clinical features. Through internal and external validation, the models exhibited sufficient ability to predict the prognosis and the possible response to ICB therapy of patients. This study provided a potential predictive approach for the precise application of ICB and support for improving the prognosis of LGG patients.

Human RecQL4 as a Novel Molecular Target for Cancer Therapy

Human RecQ helicases play diverse roles in the maintenance of genomic stability. Inactivating mutations in 3 of the 5 human RecQ helicases are responsible for the pathogenesis of Werner syndrome (WS), Bloom syndrome (BS), Rothmund-Thomson syndrome (RTS), RAPADILINO, and Baller-Gerold syndrome (BGS). WS, BS, and RTS patients are at increased risk for developing many age-associated diseases including cancer. Mutations in RecQL1 and RecQL5 have not yet been associated with any human diseases so far. In terms of disease outcome, RecQL4 deserves special attention because mutations in RecQL4 result in 3 autosomal recessive syndromes (RTS type II, RAPADILINO, and BGS). RecQL4, like other human RecQ helicases, has been demonstrated to play a crucial role in the maintenance of genomic stability through participation in diverse DNA metabolic activities. Increased incidence of osteosarcoma in RecQL4-mutated RTS patients and elevated expression of RecQL4 in sporadic cancers including osteosarcoma suggest that loss or gain of RecQL4 expression is linked with cancer susceptibility. In this review, current and future perspectives are discussed on the potential use of RecQL4 as a novel cancer therapeutic target.

Using Budding Yeast to Identify Molecules That Block Cancer Cell 'Mitotic Slippage' Only in the Presence of Mitotic Poisons

Research on the budding yeast Saccharomyces cerevisiae has yielded fundamental discoveries on highly conserved biological pathways and yeast remains the best-studied eukaryotic cell in the world. Studies on the mitotic cell cycle and the discovery of cell cycle checkpoints in budding yeast has led to a detailed, although incomplete, understanding of eukaryotic cell cycle progression. In multicellular eukaryotic organisms, uncontrolled aberrant cell division is the defining feature of cancer. Some of the most successful classes of anti-cancer chemotherapeutic agents are mitotic poisons. Mitotic poisons are thought to function by inducing a mitotic spindle checkpoint-dependent cell cycle arrest, via the assembly of the highly conserved mitotic checkpoint complex (MCC), leading to apoptosis. Even in the presence of mitotic poisons, some cancer cells continue cell division via 'mitotic slippage', which may correlate with a cancer becoming refractory to mitotic poison chemotherapeutic treatments. In this review, knowledge about budding yeast cell cycle control is explored to suggest novel potential drug targets, namely, specific regions in the highly conserved anaphase-promoting complex/cyclosome (APC/C) subunits Apc1 and/or Apc5, and in a specific N-terminal region in the APC/C co-factor cell division cycle 20 (Cdc20), which may yield molecules which block 'mitotic slippage' only in the presence of mitotic poisons.

USP2-Related Cellular Signaling and Consequent Pathophysiological Outcomes

Ubiquitin specific protease (USP) 2 is a multifunctional deubiquitinating enzyme. USP2 modulates cell cycle progression, and therefore carcinogenesis, via the deubiquitination of cyclins and Aurora-A. Other tumorigenic molecules, including epidermal growth factor and fatty acid synthase, are also targets for USP2. USP2 additionally prevents p53 signaling. On the other hand, USP2 functions as a key component of the CLOCK/BMAL1 complex and participates in rhythmic gene expression in the suprachiasmatic nucleus and liver. USP2 variants influence energy metabolism by controlling hepatic gluconeogenesis, hepatic cholesterol uptake, adipose tissue inflammation, and subsequent systemic insulin sensitivity. USP2 also has the potential to promote surface expression of ion channels in renal and intestinal epithelial cells. In addition to modifying the production of cytokines in immune cells, USP2 also modulates the signaling molecules that are involved in cytokine signaling in the target cells. Usp2 knockout mice exhibit changes in locomotion and male fertility, which suggest roles for USP2 in the central nervous system and male genital tract, respectively. In this review, we summarize the cellular events with USP2 contributions and list the signaling molecules that are upstream or downstream of USP2. Additionally, we describe phenotypic differences found in the in vitro and in vivo experimental models.