Survivin and the inner centromere protein INCENP show similar cell-cycle localization and gene knockout phenotype

Survivin as a Therapeutic Target for the Treatment of Human Cancer

Survivin was initially identified as a member of the inhibitor apoptosis (IAP) protein family and has been shown to play a critical role in the regulation of apoptosis. More recent studies showed that survivin is a component of the chromosome passenger complex and acts as an essential mediator of mitotic progression. Other potential functions of survivin, such as mitochondrial function and autophagy, have also been proposed. Survivin has emerged as an attractive target for cancer therapy because its overexpression has been found in most human cancers and is frequently associated with chemotherapy resistance, recurrence, and poor survival rates in cancer patients. In this review, we discuss our current understanding of how survivin mediates various aspects of malignant transformation and drug resistance, as well as the efforts that have been made to develop therapeutics targeting survivin for the treatment of cancer.

A Number of the N-terminal RASSF Family: RASSF7

The Ras association domain family 7 (RASSF7, also named HRC1), a potential tumor-related gene, located on human chromosome 11p15, has been identified as an important member of the N-terminal RASSF family. Whereas, the molecular biological mechanisms of RASSF7 in tumorigenesis remain to be further established. We perform a systematic review of the literature and assessment from PUBMED and MEDLINE databases in this article. RASSF7 plays a significant role in mitosis, microtubule growth, apoptosis, proliferation and differentiation. Many research literature shows that the RASSF7 could promote the occurrence and advance of human tumors by regulating Aurora B, MKK4, MKK7, JNK, YAP, MEK, and ERK, whereas, it might inhibit c-Myc and thus lead to the suppression of tumorigenesis. The pregulation of RASSF7 often occurs in various malignancies such as lung cancer, neuroblastoma, thyroid neoplasm, hepatocellular cancer, breast cancer and gastric cancer. The expression stage of RASSF7 is positively correlated with the tumor TNM stage. In this review, we primarily elaborate on the acknowledged structure and progress in the various biomechanisms and research advances of RASSF7, especially the potential relevant signaling pathways. We hope that RASSF7 , a prospective therapeutic target for human malignancies, could play an available role in future anti-cancer treatment.

Survivin Small Molecules Inhibitors: Recent Advances and Challenges

Survivin, as a member of the inhibitor of apoptosis proteins (IAPs) family, acts as a suppressor of apoptosis and plays a central role in cell division. Survivin has been considered as an important cancer drug target because it is highly expressed in many types of human cancers, while it is effectively absent from terminally differentiated normal tissues. Moreover, survivin is involved in tumor cell resistance to chemotherapy and radiation. Preclinically, downregulation of survivin expression or function reduced tumor growth induced apoptosis and sensitized tumor cells to radiation and chemotherapy in different human tumor models. This review highlights the role of survivin in promoting cellular proliferation and inhibiting apoptosis and summarizes the recent advances in and challenges of developing small-molecule survivin inhibitors.

Chromodomain on Y-like 2 (CDYL2) implicated in mitosis and genome stability regulation via interaction with CHAMP1 and POGZ

Histone H3 trimethylation on lysine 9 (H3K9me3) is a defining feature of mammalian pericentromeres, loss of which results in genome instability. Here we show that CDYL2 is recruited to pericentromeres in an H3K9me3-dependent manner and is required for faithful mitosis and genome stability. CDYL2 RNAi in MCF-7 breast cancer cells and Hela cervical cancer cells inhibited their growth, induced apoptosis, and provoked both nuclear and mitotic aberrations. Mass spectrometry analysis of CDYL2-interacting proteins identified the neurodevelopmental disease-linked mitotic regulators CHAMP1 and POGZ, which are associated with a central non-conserved region of CDYL2. RNAi rescue assays identified both the CDYL2 chromodomain and the CHAMP1-POGZ interacting region as required and, together, sufficient for CDYL2 regulation of mitosis and genome stability. CDYL2 RNAi caused loss of CHAMP1 localization at pericentromeres. We propose that CDYL2 functions as an adaptor protein that connects pericentromeric H3K9me3 with CHAMP1 and POGZ to ensure mitotic fidelity and genome stability.

Increased Aurora B expression reduces substrate phosphorylation and induces chromosomal instability

Increased Aurora B protein expression, which is common in cancers, is expected to increase Aurora B kinase activity, yielding elevated phosphorylation of Aurora B substrates. In contrast, here we show that elevated expression of Aurora B reduces phosphorylation of six different Aurora B substrates across three species and causes defects consistent with Aurora B inhibition. Complexes of Aurora B and its binding partner INCENP autophosphorylate in trans to achieve full Aurora B activation. Increased expression of Aurora B mislocalizes INCENP, reducing the local concentration of Aurora B:INCENP complexes at the inner centromere/kinetochore. Co-expression of INCENP rescues Aurora B kinase activity and mitotic defects caused by elevated Aurora B. However, INCENP expression is not elevated in concert with Aurora B in breast cancer, and increased expression of Aurora B causes resistance rather than hypersensitivity to Aurora B inhibitors. Thus, increased Aurora B expression reduces, rather than increases, Aurora B kinase activity.

Single-cell RNA-seq uncovered hemocyte functional subtypes and their differentiational characteristics and connectivity with morphological subpopulations in Litopenaeus vannamei

Hemocytes play central roles in shrimp immune system, whereas whose subclasses have not yet been completely defined. At present, the morphological classification of hemocytes is inadequate to classify the complete hemocyte repertoire and elucidate the functions and differentiation and maturation processes. Based on single-cell RNA sequencing (scRNA-seq) of hemocytes in healthy Litopenaeus vannamei, combined with RNA-FISH and flow cytometric sorting, we identified three hemocyte clusters including TGase+ cells, CTL+ cells and Crustin+ cells, and further determined their functional properties, potential differentiation trajectory and correspondence with morphological subpopulations. The TGase+ cells were mainly responsible for the coagulation, exhibiting distinguishable characteristics of hyalinocyte, and appeared to be developmentally arrested at an early stage of hemocyte differentiation. The CTL+ cells and Crustin+ cells arrested at terminal stages of differentiation mainly participated in recognizing foreign pathogens and initiating immune defense responses, owning distinctive features of granule-containing hemocytes. Furthermore, we have revealed the functional sub-clusters of three hemocyte clusters and their potential differentiation pathways according to the expression of genes involved in cell cycle, cell differentiation and immune response, and the successive differentiation and maturation of hyalinocytes to granule-containing hemocytes have also mapped. The results revealed the diversity of shrimp hemocytes and provide new theoretical rationale for hemocyte classification, which also facilitate systematic research on crustacean immunity.

The genotypic and phenotypic impact of hypoxia microenvironment on glioblastoma cell lines

BACKGROUND

Glioblastoma is a fatal brain tumour with a poor patient survival outcome. Hypoxia has been shown to reprogram cells towards a stem cell phenotype associated with self-renewal and drug resistance properties. Activation of hypoxia-inducible factors (HIFs) helps in cellular adaptation mechanisms under hypoxia. Similarly, miRNAs are known to be dysregulated in GBM have been shown to act as critical mediators of the hypoxic response and to regulate key processes involved in tumorigenesis.

METHODS

Glioblastoma (GBM) cells were exposed to oxygen deprivation to mimic a tumour microenvironment and different cell aspects were analysed such as morphological changes and gene expression of miRNAs and survival genes known to be associated with tumorigenesis.

RESULTS

It was observed that miR-128a-3p, miR-34-5p, miR-181a/b/c, were down-regulated in 6 GBM cell lines while miR-17-5p and miR-221-3p were upregulated when compared to a non-GBM control. When the same GBM cell lines were cultured under hypoxic microenvironment, a further 4-10-fold downregulation was observed for miR-34-5p, miR-128a-3p and 181a/b/c while a 3-6-fold upregulation was observed for miR-221-3p and 17-5p for most of the cells. Furthermore, there was an increased expression of SOX2 and Oct4, GLUT-1, VEGF, Bcl-2 and survivin, which are associated with a stem-like state, increased metabolism, altered angiogenesis and apoptotic escape, respectively.

CONCLUSION

This study shows that by mimicking a tumour microenvironment, miRNAs are dysregulated, stemness factors are induced and alteration of the survival genes necessary for the cells to adapt to the micro-environmental factors occurs. Collectively, these results might contribute to GBM aggressiveness.

Single-cell RNA sequencing reveals differential cell cycle activity in key cell populations during nephrogenesis

The kidney is a complex organ composed of more than 30 terminally differentiated cell types that all are required to perform its numerous homeostatic functions. Defects in kidney development are a significant cause of chronic kidney disease in children, which can lead to kidney failure that can only be treated by transplant or dialysis. A better understanding of molecular mechanisms that drive kidney development is important for designing strategies to enhance renal repair and regeneration. In this study, we profiled gene expression in the developing mouse kidney at embryonic day 14.5 at single-cell resolution. Consistent with previous studies, clusters with distinct transcriptional signatures clearly identify major compartments and cell types of the developing kidney. Cell cycle activity distinguishes between the "primed" and "self-renewing" sub-populations of nephron progenitors, with increased expression of the cell cycle-related genes Birc5, Cdca3, Smc2 and Smc4 in "primed" nephron progenitors. In addition, augmented expression of cell cycle related genes Birc5, Cks2, Ccnb1, Ccnd1 and Tuba1a/b was detected in immature distal tubules, suggesting cell cycle regulation may be required for early events of nephron patterning and tubular fusion between the distal nephron and collecting duct epithelia.

Development of Multi-Scale X-ray Fluorescence Tomography for Examination of Nanocomposite-Treated Biological Samples

Simple Summary

Metal-oxide nanomaterials enter cancer and normal cells even when not specifically targeted, and often interact with specific cellular structures and biological molecules solely due to their innate physical-chemical properties. This raises concerns for the use of nanoparticles, which can be alleviated only with rigorous studies of nanoparticle–cell interactions, studies independent of post-interaction labeling of nanomaterials. X-ray fluorescence microscopy is an imaging technique that quantifies and maps all chemical elements from the periodic table solely based on their native fluorescence excited by the incoming X-ray. We used two different instruments to interrogate the same sample in 3D at two different resolutions and determine heterogeneity of cell-to-cell interactions with nanomaterials, as well as subcellular nanoparticle distribution. This is the first example of multi-scale 3D X-ray fluorescence imaging. This work begins a new era of study on how nanoparticle-based therapies can be developed to be more predictable and safer for use.

Abstract

Research in cancer nanotechnology is entering its third decade, and the need to study interactions between nanomaterials and cells remains urgent. Heterogeneity of nanoparticle uptake by different cells and subcellular compartments represent the greatest obstacles to a full understanding of the entire spectrum of nanomaterials’ effects. In this work, we used flow cytometry to evaluate changes in cell cycle associated with non-targeted nanocomposite uptake by individual cells and cell populations. Analogous single cell and cell population changes in nanocomposite uptake were explored by X-ray fluorescence microscopy (XFM). Very few nanoparticles are visible by optical imaging without labeling, but labeling increases nanoparticle complexity and the risk of modified cellular uptake. XFM can be used to evaluate heterogeneity of nanocomposite uptake by directly imaging the metal atoms present in the metal-oxide nanocomposites under investigation. While XFM mapping has been performed iteratively in 2D with the same sample at different resolutions, this study is the first example of serial tomographic imaging at two different resolutions. A cluster of cells exposed to non-targeted nanocomposites was imaged with a micron-sized beam in 3D. Next, the sample was sectioned for immunohistochemistry as well as a high resolution “zoomed in” X-ray fluorescence (XRF) tomography with 80 nm beam spot size. Multiscale XRF tomography will revolutionize our ability to explore cell-to-cell differences in nanomaterial uptake.

Targeted RNAi of BIRC5/Survivin Using Antibody-Conjugated Poly(Propylene Imine)-Based Polyplexes Inhibits Growth of PSCA-Positive Tumors

Delivery of siRNAs for the treatment of tumors critically depends on the development of efficient nucleic acid carrier systems. The complexation of dendritic polymers (dendrimers) results in nanoparticles, called dendriplexes, that protect siRNA from degradation and mediate non-specific cellular uptake of siRNA. However, large siRNA doses are required for in vivo use due to accumulation of the nanoparticles in sinks such as the lung, liver, and spleen. This suggests the exploration of targeted nanoparticles for enhancing tumor cell specificity and achieving higher siRNA levels in tumors. In this work, we report on the targeted delivery of a therapeutic siRNA specific for BIRC5/Survivin in vitro and in vivo to tumor cells expressing the surface marker prostate stem cell antigen (PSCA). For this, polyplexes consisting of single-chain antibody fragments specific for PSCA conjugated to siRNA/maltose-modified poly(propylene imine) dendriplexes were used. These polyplexes were endocytosed by PSCA-positive 293T^PSCA/ffLuc and PC3^PSCA cells and caused knockdown of reporter gene firefly luciferase and Survivin expression, respectively. In a therapeutic study in PC3^PSCA xenograft-bearing mice, significant anti-tumor effects were observed upon systemic administration of the targeted polyplexes. This indicates superior anti-tumor efficacy when employing targeted delivery of Survivin-specific siRNA, based on the additive effects of siRNA-mediated Survivin knockdown in combination with scFv-mediated PSCA inhibition.

Circulating Survivin Protein Levels in Lung Cancer Patients Treated With Platinum-Based Chemotherapy

The survivin protein contributes to the development and progression of tumors. Protein expression and mRNA levels correlate with clinicopathological parameters and survival of cancer patients. Our purpose was to evaluate whether circulating survivin levels have any diagnostic or predictive value in lung cancer. 118 patients with advanced stage lung cancer participated in our study. 53 suffered from adenocarcinoma (ADC), 33 from squamous cell carcinoma (SqCC), and 32 from small cell lung cancer (SCLC). We also enrolled 21 control subjects. Blood samples were collected before and after two cycles of chemotherapy. We measured survivin concentrations with ELISA. Non-parametric tests were used for analysis. We did not find significant difference in survivin levels between patients and control subjects (17.19/0–829.74/vs. 49.13/0–165.92/pg/ml; p = 0.07). We found lower survivin concentrations in patients with SqCC (0/0–171.24/pg/ml) than in those with ADC (24.94/0–626.46 pg/ml) and SCLC (45.51/0–829.74/pg/ml) (ADC vs. SqCC p < 0.0001, ADC vs. SCLC p = 0.0405, SqCC vs. SCLC p < 0.0001). Survivin levels were higher in stage IV patients than in patients without distant metastases (p = 0.0061), and concentrations were progressively higher with increasing number of metastatic organ sites (p = 0.04). We observed a decrease in survivin levels in ADC patients after platinum plus pemetrexed chemotherapy (26.22/0–626.46/pg/ml before vs. 0/0–114.36/pg/ml after; p = 0.01). Neither progression-free nor overall survival correlated with survivin levels at baseline. Our data imply that survivin may be involved in the development of metastases and it might be used as a biomarker of disease progression. However, circulating survivin concentrations do not predict survival of patients with lung cancer.

The right place at the right time: Aurora B kinase localization to centromeres and kinetochores

The fidelity of chromosome segregation during mitosis is intimately linked to the function of kinetochores, which are large protein complexes assembled at sites of centromeric heterochromatin on mitotic chromosomes. These key "orchestrators" of mitosis physically connect chromosomes to spindle microtubules and transduce forces through these connections to congress chromosomes and silence the spindle assembly checkpoint. Kinetochore-microtubule attachments are highly regulated to ensure that incorrect attachments are not prematurely stabilized, but instead released and corrected. The kinase activity of the centromeric protein Aurora B is required for kinetochore-microtubule destabilization during mitosis, but how the kinase acts on outer kinetochore substrates to selectively destabilize immature and erroneous attachments remains debated. Here, we review recent literature that sheds light on how Aurora B kinase is recruited to both centromeres and kinetochores and discuss possible mechanisms for how kinase interactions with substrates at distinct regions of mitotic chromosomes are regulated.

Prognostic Role of Survivin and Macrophage Infiltration Quantified on Protein and mRNA Level in Molecular Subtypes Determined by RT-qPCR of KRT5, KRT20, and ERBB2 in Muscle-Invasive Bladder Cancer Treated by Adjuvant Chemotherapy

OBJECTIVES

Bladder cancer is a heterogeneous malignancy. Therefore, it is difficult to find single predictive markers. Moreover, most studies focus on either the immunohistochemical or molecular assessment of tumor tissues by next-generation sequencing (NGS) or PCR, while a combination of immunohistochemistry (IHC) and PCR for tumor marker assessment might have the strongest impact to predict outcome and select optimal therapies in real-world application. We investigated the role of proliferation survivin/BIRC5 and macrophage infiltration (CD68, MAC387, CLEVER-1) on the basis of molecular subtypes of bladder cancer (KRT5, KRT20, ERBB2) to predict outcomes of adjuvant treated muscle-invasive bladder cancer patients with regard to progression-free survival (PFS) and disease-specific survival (DSS).

MATERIALS AND METHODS

We used tissue microarrays (TMA) from n = 50 patients (38 males, 12 female) with muscle-invasive bladder cancer. All patients had been treated with radical cystectomy followed by adjuvant triple chemotherapy. Median follow-up time was 60.5 months. CD68, CLEVER-1, MAC387, and survivin protein were detected by immunostaining and subsequent visual inspection. BIRC5, KRT5, KRT20, ERBB2, and CD68 mRNAs were detected by standardized RT-qPCR after tissue dot RNA extraction using a novel stamp technology. All these markers were evaluated in three different centers of excellence.

RESULTS

Nuclear staining rather than cytoplasmic staining of survivin predicted DSS as a single marker with high levels of survivin being associated with better PFS and DSS upon adjuvant chemotherapy (p = 0.0138 and p = 0.001, respectively). These results were validated by the quantitation of BIRC5 mRNA by PCR (p = 0.0004 and p = 0.0508, respectively). Interestingly, nuclear staining of survivin protein was positively associated with BIRC5 mRNA, while cytoplasmic staining was inversely related, indicating that the translocation of survivin protein into the nucleus occurred at a discrete, higher level of its mRNA. Combining survivin/BIRC5 levels based on molecular subtype being assessed by KRT20 expression improved the predictive value, with tumors having low survivin/BIRC5 and KRT20 mRNA levels having the best survival (75% vs. 20% vs. 10% 5-year DSS, p = 0.0005), and these values were independent of grading, node status, and tumor stage in multivariate analysis (p = 0.0167). Macrophage infiltration dominated in basal tumors and was inversely related with the luminal subtype marker gene expression. The presence of macrophages in survivin-positive or ERBB2-positive tumors was associated with worse DSS.

CONCLUSIONS

For muscle-invasive bladder cancer patients, the proliferative activity as determined by the nuclear staining of survivin or RT-qPCR on the basis of molecular subtype characteristics outperforms single marker detections and single technology approaches. Infiltration by macrophages detected by IHC or PCR is associated with worse outcome in defined subsets of tumors. The limitations of this study are the retrospective nature and the limited number of patients. However, the number of molecular markers has been restricted and based on predefined assumptions, which resulted in the dissection of muscle-invasive disease into tumor-biological axes of high prognostic relevance, which warrant further investigation and validation.

Inhibition of survivin induces spindle disorganization, chromosome misalignment, and DNA damage during mouse embryo development

The early embryonic development is important for the subsequent embryo implantation, and any defects in this process can lead to embryonic aneuploidy, which causes miscarriage and birth defects. Survivin is the member of inhibitor of apoptosis protein (IAP) family, and it is also an essential subunit of chromosomal passenger complex (CPC), which regulates both apoptosis and cell cycle control in many models. However, the roles of survivin in mouse early embryos remain unclear. In the present study, we showed that survivin activity was essential for mouse early embryo development. Our results showed that survivin mainly accumulated at chromosomes at metaphase stage and located at the spindle midzone at anaphase and telophase stages during the first cleavage. Loss of survivin activity led to the failure of cleavage in early mouse embryos. Further analysis indicated that survivin involved into spindle organization and chromosome alignment. Moreover, inhibition of survivin induced oxidative stress and DNA damage, showing with the increase of ROS level, the positive γH2A signal, and the increase of Rad51 level. We also observed the occurrence of autophagy and apoptosis in the survivin-inhibited embryos. In summary, our study suggested that survivin was a critical regulator for early embryo development through its regulation on spindle organization, chromosome alignment, and DNA damage.

Combination Therapies of Artemisinin and its Derivatives as a Viable Approach for Future Cancer Treatment

BACKGROUND

Many anticancer drugs have been developed for clinical usage till now, but the major problem is the development of drug-resistance over a period of time in the treatment of cancer. Anticancer drugs produce huge adverse effects, ultimately leading to death of the patient. Researchers have been focusing on the development of novel molecules with higher efficacy and lower toxicity; the anti-malarial drug artemisinin and its derivatives have exhibited cytotoxic effects.

METHODS

We have done extensive literature search for artemisinin for its new role as anti-cancer agent for future treatment. Last two decades papers were referred for deep understanding to strengthen its role.

RESULT

Literature shows changes at 9, 10 position in the artemisinin structure produces anticancer activity. Artemisinin shows anticancer activity in leukemia, hepatocellular carcinoma, colorectal and breast cancer cell lines. Artemisinin and its derivatives have been studied as combination therapy with several synthetic compounds, RNA interfaces, recombinant proteins and antibodies etc., for synergizing the effect of these drugs. They produce an anticancer effect by causing cell cycle arrest, regulating signaling in apoptosis, angiogenesis and cytotoxicity activity on the steroid receptors. Many novel formulations of artemisinin are being developed in the form of carbon nanotubes, polymer-coated drug particles, etc., for delivering artemisinin, since it has poor water/ oil solubility and is chemically unstable.

CONCLUSION

We have summarize the combination therapies of artemisinin and its derivatives with other anticancer drugs and also focussed on recent developments of different drug delivery systems in the last 10 years. Various reports and clinical trials of artemisinin type drugs indicated selective cytotoxicity along with minimal toxicity thus projecting them as promising anti-cancer agents in future cancer therapies.

BIRC5 Expression is Regulated in Uterine Epithelium During the Estrous Cycle

Baculoviral inhibitor of apoptosis repeat-containing 5 (Birc5), also known as survivin, is a member of the inhibitor of apoptosis (IAP) family of proteins and regulates the size of tissues through cell division control. The uterus is the most dynamically sized organ among tissues during the estrous cycle. Although Birc5 is expressed in some terminally differentiated cells, the regulation of its expression in the uterus remains unknown. We investigated the regulation of Birc5 expression in the mouse uterus. RT-PCR analysis showed that Birc5 was expressed in various tissues, including the uterus; the expression level of Birc5 was significantly higher at the diestrus stage. Immunohistochemistry and Western blotting analysis revealed that Birc5 was more active in luminal and glandular epithelium than in endometrial stroma. In ovariectomized mice, Birc5 expression in the uterus was gradually increased by estrogen treatment; however, progesterone injection decreased its expression. Estrogen-induced Birc5 expression was blocked by treatment with estrogen receptor antagonist, ICI 182, 780 and progesterone-reduced Birc5 expression was inhibited by the progesterone receptor antagonist RU486. These results suggest that Birc5 expression is dynamically regulated by a combination of estrogen and progesterone via their receptor-mediated signaling.

Impaired histomorphology might provoke cell cycle regulators alteration in thymus of children with various congenital heart defects

Thymus, as a primary site of appropriate adaptive immunity formation, is an essential organ in face of a self-tolerance as well as a potential menace from impairment of body integrity. Due to vital selection processes during differentiation and maturation of T lymphocytes, control over cell survival and programmed cell death must be orchestrated in detail. Indeed, thymus is highly sensitive to wide spectrum of stressors that initiate acute structural changes. Hypoxia, one of the most common complications in congenital heart defects (CHDs) patients, provokes stress-induced thymus involution. Disrupted embryolonic development of thymus in association with congenital heart defects, may negatively affect physiological immune mechanisms. We propose that detailed analysis of thymic morphology could critically contribute to unveil the pathophysiology of diseases associated with disrupted adaptive immunity in children with heterogeneous congenital heart diseases.

Small-Molecule Intervention At The Dimerization Interface Of Survivin By Novel Rigidized Scaffolds

Introduction

Survivin is a nodal protein involved in several cellular pathways. It is a member of the IAP family and an integral component of the chromosomal passenger complex, where it binds to borealin and INCENP through its dimerization interface. By targeting survivin with a small molecule at its dimerization interface, inhibition of the proliferation of cancer cells has been suggested. With Abbott 8, a small-molecule dimerization inhibitor has been recently reported. The structure–activity relationship of this series of inhibitors implied that the middle pyridin-2(1H)-one ring did not tolerate modifications of any kind.

Methods

Based on the synthetic strategy of Abbott 8 using multicomponent reactions, we synthesized a series of small molecules bearing a novel rigidized core scaffold. This rigidization strategy was accomplished by integrating the pyridin-2(1H)-one and its 6-phenyl substituent into a tricyclic structure, linking position 5 of pyridin-2(1H)-one to the phenyl substituent by rings of different sizes. The new scaffolds were designed based on in silico molecular dynamics of survivin.

Results

Binding of these rigidized scaffolds to the recombinant L54M mutant of survivin was evaluated, revealing affinities in the low micromolar range.

Conclusion

This easily accessible, new class of survivin-dimerization modulators is an interesting starting point for further lead optimization.

What is the impact of BIRC5 gene polymorphisms on urinary cancer susceptibility? Evidence from 9348 subjects

As a member of apoptosis inhibition gene family, baculoviral IAP repeat containing 5 (BIRC5) protein acts as a survival factor in oncology through multiple ways. There are huge inconsistent results between urinary cancer risk and BIRC5 polymorphisms, so we searched and documented all eligible articles to clear up the mystery with the help of meta-analysis. According to the inclusion and exclusion criteria, we performed an overall search in Web of Science, PubMed, Google Scholar, Medline, CNKI and Wanfang database with pre-set search strategy up to November 2019. Z-test was performed to determine the statistical difference by Odds ratios (ORs) and 95% confidence intervals (CIs). The stability of the pooled ORs was conducted by one-way sensitivity analyses, Begg's funnel plots and Egger's test were employed to access the potential publication bias. The relationship of polymorphisms and BIRC5 expression was exposed by in-silico analysis, as well as the effects to tumorigenesis and prognosis. Finally, we enrolled 19 case-control studies to conducted this meta-analysis. An upgrade risk in rs9904341 of BIRC5 were revealed to be associated with urinary cancer in allele contrast model (OR = 1.222, P = 0.012), homozygote contrast model (OR = 1.579, P = 0.0001) and recessive contrast model (OR = 1.433, P < 0.001), as well as rs2071214 polymorphism in the subgroup analysis of BCa in allele contrast model (OR = 1.362, P = 0.011) and recessive contrast model (OR = 1.417, P = 0.015). On the other hand, rs17878467 variant plays an important role in prevent the tumorigenicity of urinary cancer in allele contrast model (OR = 0.672, P = 0.009), heterozygote contrast model (OR = 0.585, P = 0.006) and dominant contrast model (OR = 0.595, P = 0.004). In conclusion, we found that BIRC5 rs9904341, rs2071214 polymorphisms might cause the increased risk of urinary cancer, while rs17878467 reduces risk.

Borealin-nucleosome interaction secures chromosome association of the chromosomal passenger complex

Chromosome association of the chromosomal passenger complex (CPC; consisting of Borealin, Survivin, INCENP, and the Aurora B kinase) is essential to achieve error-free chromosome segregation during cell division. Hence, understanding the mechanisms driving the chromosome association of the CPC is of paramount importance. Here using a multifaceted approach, we show that the CPC binds nucleosomes through a multivalent interaction predominantly involving Borealin. Strikingly, Survivin, previously suggested to target the CPC to centromeres, failed to bind nucleosomes on its own and requires Borealin and INCENP for its binding. Disrupting Borealin-nucleosome interactions excluded the CPC from chromosomes and caused chromosome congression defects. We also show that Borealin-mediated chromosome association of the CPC is critical for Haspin- and Bub1-mediated centromere enrichment of the CPC and works upstream of the latter. Our work thus establishes Borealin as a master regulator determining the chromosome association and function of the CPC.

Unravelling the molecular mechanisms of nickel in woodlice

During the last few years, there has been an alarming increase in the amount of nickel (Ni) being released into the environment, primarily due to its use in the production of stainless steel but also from other sources such as batteries manufacturing and consequent disposal. The established biotic ligand models provide precise estimates for Ni bioavailability, in contrast, studies describing the mechanisms underpinning toxicological effect of Ni are scarce. This study exploits RNA-seq to determine the transcriptomic responses of isopods using Porcellionides pruinosus as an example of a terrestrial metal-resistant woodlouse. Furthermore, the recently proposed model for Ni adverse outcome pathways (Ni-AOP) presents an unprecedented opportunity to fit isopod responses to Ni toxicity and define Porcellionides pruinosus as a metalomic model. Prior to this study, P. pruinosus represented an important environmental sentinel, though lacking genetic/omic data. The reference transcriptome generated here thus represents a major advance and a novel resource. A detailed annotation of the transcripts obtained is presented together with the homology to genes/gene products from Metazoan and Arthropoda phylum, Gene Ontology (GO) classification, clusters of orthologous groups (COG) and assignment to KEGG metabolic pathways. The differential gene expression comparison was determined in response to nickel (Ni) exposure and used to derive the enriched pathways and processes. It revealed a significant impact on ion trafficking and storage, oxidative stress, neurotoxicity, reproduction impairment, genetics and epigenetics. Many of the processes observed support the current Ni-AOP although the data highlights that the current model can be improved by including epigenetic endpoints, which represents key chronic risks under a scenario of Ni toxicity.

Targeting the Chromosomal Passenger Complex Subunit INCENP Induces Polyploidization, Apoptosis, and Senescence in Neuroblastoma

Chromosomal passenger complex (CPC) has been demonstrated to be a potential target of cancer therapy by inhibiting Aurora B or survivin in different types of cancer including neuroblastoma. However, chemical inhibition of either Aurora B or survivin does not target CPC specifically due to off-target effects or CPC-independent activities of these two components. In a previous chromatin-focused siRNA screen, we found that neuroblastoma cells were particularly vulnerable to loss of INCENP, a gene encoding a key scaffolding component of the CPC. In this study, INCENP was highly expressed by neuroblastoma cells, and its expression decreased following retinoic acid-induced neuroblastoma differentiation. Elevated levels of INCENP were significantly associated with poor prognosis in primary tumors of neuroblastoma patients with high-risk disease. Genetic silencing of INCENP reduced the growth of both MYCN-wild-type and MYCN-amplified neuroblastoma cell lines in vitro and decreased the growth of neuroblastoma xenografts in vivo, with significant increases in murine survival. Mechanistically, INCENP depletion suppressed neuroblastoma cell growth by inducing polyploidization, apoptosis, and senescence. In most neuroblastoma cell lines tested in vitro, apoptosis was the primary cell fate after INCENP silencing due to induction of DNA damage response and activation of the p53-p21 axis. These results confirm that CPC is a therapeutic target in neuroblastoma, and targeting INCENP is a novel way to disrupt the activity of CPC and inhibit tumor progression in neuroblastoma. SIGNIFICANCE: Dysregulation of INCENP contributes to neuroblastoma tumorigenesis and targeting INCENP presents a novel strategy to disrupt the activity of chromosomal passenger complex and inhibit neuroblastoma progression.

Survivin Impairs the Apoptotic Machinery in CD4+ T Cells of Patients with Ulcerative Colitis

BACKGROUND

The increase in CD4+ T cell infiltration and overproduction of CD4+ T cell-associated cytokines have been observed in the inflamed colon mucosa of patients with ulcerative colitis (UC); the underlying mechanisms are not fully understood. Survivin plays a critical role in the interference with apoptotic machinery. This study aims to elucidate the role of survivin in the interference with the apoptotic machinery in CD4+ T cells of UC patients.

METHODS

Peripheral blood samples were collected from UC patients (UC group) and healthy subjects (healthy group). The apoptotic status in CD4+ T cells was analyzed by flow cytometry.

RESULTS

We observed that the expression of survivin was significantly higher in CD4+ T cells of UC patients than in healthy subjects. UC CD4+ T cells were resistant to apoptosis induction. A complex of survivin and c-Myc, the transcription factor of FasL, was detected in CD4+ T cells in UC patients, which prevented the binding of c-Myc to the FasL promoter and interfered with the expression of FasL. Increased expression of survivin prevented the activation-induced CD4+ T cells from apoptosis.

CONCLUSIONS

The data indicate that UC CD4+ T cells express high levels of survivin, which impairs the apoptotic machinery in CD4+ T cells and prevents the activation-induced CD4+ T cell apoptosis. Therefore, target therapy against survivin has translational potential in the treatment of UC patients.

The survivin molecule as a double-edged sword in cellular physiologic and pathologic conditions and its role as a potential biomarker and therapeutic target in cancer

Survivin is a member of the family of apoptosis inhibitory proteins with increased expression level in most cancerous tissues. Evidence shows that survivin plays regulatory roles in proliferation or survival of normal adult cells, principally vascular endothelial cells, T lymphocytes, primitive hematopoietic cells, and polymorphonuclear neutrophils. Survivin antiapoptotic role is, directly and indirectly, related to caspase proteins and shows its role in cell division through the chromosomal passenger complex. Survivin contains many genetic polymorphisms that the role of some variations has been proven in several cancers. The -31G/C polymorphism is one of the most important survivin mutations which is located in the promoter region on a CDE/CHR motif. This polymorphism can upregulate the survivin messenger RNA. In addition, its allele C can increase the risk of cancers in 1.27-fold than allele G. Considering the fundamental role of survivin in different cancers, this protein could be considered as a new therapeutic target in cancer treatment. For this purpose, various strategies have been designed including the prevention of survivin expression through inhibition of mRNA translation using antagonistic molecules, inhibition of survivin gene function through small inhibitory molecules, gene therapy, and immunotherapy. In this study, we describe the structure, played roles in physiological and pathological states and genetic polymorphisms of survivin. Finally, the role of survivin as a potential target in cancer therapy given challenges ahead has been discussed.

Elevated Expressions of Survivin and Endoglin in Patients with Hepatic Carcinoma

OBJECTIVE

To investigate expression profiles of survivin and endoglin in patients with hepatic carcinoma.

MATERIALS AND METHODS

Cancerous tissues (hepatic carcinoma group) of 48 patients with hepatic carcinoma and adjacent noncancerous hepatic tissues (control group) were used as objects of study. Histopathological staining [hematoxylin & eosin (H&E) staining] was used to study the pathological differences in hepatic tissues between hepatic carcinoma group and control group. Moreover, survivin and endoglin protein expressions in hepatic tissues in hepatic carcinoma group and control group were detected via western blotting. Finally, Statistical Product and Service Solutions 17.0 statistical software was used to analyze the differences in survivin and endoglin expressions in hepatic tissues between hepatic carcinoma group and control group.

RESULTS

H&E staining showed that histopathological features in hepatic carcinoma group were significantly different from those in control group. Compared with those in control group, the cell structure in hepatic carcinoma group was damaged, karyopyknosis was obvious, and the hepatic injury was serious. Reverse transcription-polymerase chain reaction showed that survivin and endoglin mRNA expression levels in hepatic carcinoma group were significantly increased compared with those in control group. Besides, immunofluorescence method and western blotting revealed the low expressions of survivin and endoglin proteins in tissues in control group, which were obviously lower than those in hepatic tissues in hepatic carcinoma group. Results of analyses of variance showed that the expressions of survivin and endoglin in normal hepatic tissues and cancerous tissues had statistically significant differences (p < 0.01). Furthermore, expressions of survivin and endoglin were significantly associated with histological grade, tumor size, and tumor, node, metastasis (TNM) stage.

CONCLUSION

Elevated expressions of survivin and endoglin are associated with histological grade, tumor size, and TNM stage in patients with hepatic carcinoma, indicating that survivin and endoglin might be involved in the pathogenesis of hepatic carcinoma and therapeutic targeting them might be a novel approach for the treatment of hepatic carcinoma.

Survivin modulatory role in autoimmune and autoinflammatory diseases

Baculoviral IAP repeat containing 5 (BIRC5) gene encodes the important protein as survivin, a multifunctional protein, which is involved in cellular and molecular networks, progression of cell cycle, homeostasis, developmental morphogenesis, and apoptosis. The proximal BIRC5 promoter possesses specific binding sites for key transcription factors such as nuclear factor κB and signal transducer and activator of transcription 3. Upregulation of survivin exacerbates the autoimmune diseases (AIDs) including multiple sclerosis and myasthenia gravis by reducing the activity threshold of survivin-specific cytotoxic T cells. DNA damage along with upregulation or downregulation of survivin have been demonstrated in initiation and pathogenesis of cancers and AIDs. However, detailed mechanism of survivin function in pathogenesis of AIDs is not well understood. This review focuses on the structure, specificity, regulation, and function of survivin in physiologic conditions and pathogenesis of AIDs.

Survivin at a glance

Survivin (also known as BIRC5) is an evolutionarily conserved eukaryotic protein that is essential for cell division and can inhibit cell death. Normally it is only expressed in actively proliferating cells, but is upregulated in most, if not all cancers; consequently, it has received significant attention as a potential oncotherapeutic target. In this Cell Science at a Glance article and accompanying poster, we summarise our knowledge of survivin 21 years on from its initial discovery. We describe the structure, expression and function of survivin, highlight its interactome and conclude by describing anti-survivin strategies being trialled.

Downregulation of Survivin contributes to cell-cycle arrest during postnatal cardiac development in a severe spinal muscular atrophy mouse model

Spinal muscular atrophy (SMA) is the leading genetic cause of infant mortality, characterized by progressive degeneration of spinal-cord motor neurons, leading to atrophy of skeletal muscles. However, accumulating evidence indicates that it is a multi-system disorder, particularly in its severe forms. Several studies delineated structural and functional cardiac abnormalities in SMA patients and mouse models, yet the abnormalities have been primarily attributed to autonomic dysfunction. Here, we show in a severe mouse model that its cardiomyocytes undergo G0/G1 cell-cycle arrest and enhanced apoptosis during postnatal development. Microarray and real-time RT-PCR analyses revealed that a set of genes associated with cell cycle and apoptosis were dysregulated in newborn pups. Of particular interest, the Birc5 gene, which encodes Survivin, an essential protein for heart development, was down-regulated even on pre-symptomatic postnatal day 0. Interestingly, cultured cardiomyocytes depleted of SMN recapitulated the gene expression changes including downregulation of Survivin and abnormal cell-cycle progression; and overexpression of Survivin rescued the cell-cycle defect. Finally, increasing SMN in SMA mice with a therapeutic antisense oligonucleotide improved heart pathology and recovered expression of deregulated genes. Collectively, our data demonstrate that the cardiac malfunction of the severe SMA mouse model is mainly a cell-autonomous defect, caused by widespread gene deregulation in heart tissue, particularly of Birc5, resulting in developmental abnormalities through cell-cycle arrest and apoptosis.

Asymmetric cell division-dominant neutral drift model for normal intestinal stem cell homeostasis

The normal intestinal epithelium is continuously regenerated at a rapid rate from actively cycling Lgr5-expressing intestinal stem cells (ISCs) that reside at the crypt base. Recent mathematical modeling based on several lineage-tracing studies in mice shows that the symmetric cell division-dominant neutral drift model fits well with the observed in vivo growth of ISC clones and suggests that symmetric divisions are central to ISC homeostasis. However, other studies suggest a critical role for asymmetric cell division in the maintenance of ISC homeostasis in vivo. Here, we show that the stochastic branching and Moran process models with both a symmetric and asymmetric division mode not only simulate the stochastic growth of the ISC clone in silico but also closely fit the in vivo stem cell dynamics observed in lineage-tracing studies. In addition, the proposed model with highest probability for asymmetric division is more consistent with in vivo observations reported here and by others. Our in vivo studies of mitotic spindle orientations and lineage-traced progeny pairs indicate that asymmetric cell division is a dominant mode used by ISCs under normal homeostasis. Therefore, we propose the asymmetric cell division-dominant neutral drift model for normal ISC homeostasis. NEW & NOTEWORTHY The prevailing mathematical model suggests that intestinal stem cells (ISCs) divide symmetrically. The present study provides evidence that asymmetric cell division is the major contributor to ISC maintenance and thus proposes an asymmetric cell division-dominant neutral drift model. Consistent with this model, in vivo studies of mitotic spindle orientation and lineage-traced progeny pairs indicate that asymmetric cell division is the dominant mode used by ISCs under normal homeostasis.

CCAR2/DBC1 and Hsp60 Positively Regulate Expression of Survivin in Neuroblastoma Cells

CCAR2 (cell cycle and apoptosis regulator 2) controls a variety of cellular functions; however, its main function is to regulate cell survival and cell death in response to genotoxic and metabolic stresses. Recently, we reported that CCAR2 protects cells from apoptosis following mitochondrial stress, possibly by co-operating with Hsp60. However, it is not clear how CCAR2 and Hsp60 control cell survival and death. Here, we found that depleting CCAR2 and Hsp60 downregulated expression of survivin, a member of the inhibitor of apoptosis (IAP) family. Survivin expression in neuroblastoma tissues and human cancer cell lines correlated positively with expression of CCAR2 and Hsp60. Furthermore, high expression of CCAR2, Hsp60, and survivin was associated with poor survival of neuroblastoma patients. In summary, both CCAR2 and Hsp60 are required for expression of survivin, and both promote cancer cell survival, at least in part, by maintaining survivin expression. Therefore, CCAR2, Hsp60, and survivin are candidate tumor biomarkers and prognostic markers in neuroblastomas.

Survivin regulates chromosome segregation by modulating the phosphorylation of Aurora B during porcine oocyte meiosis

SURVIVIN is an essential chromosomal passenger complex (CPC) subunit and participates in cell division. In this study, we used porcine oocyte as a model to investigate the roles of Survivin during porcine oocyte maturation. Survivin was highly expressed in germinal vesicle (GV) and germinal vesicle breakdown (GVBD) stages oocytes, mainly localized in the GV at GV stage and on the chromosomes after GVBD. We have used RNA interference to specifically deplete Survivin in oocytes during in vitro maturation (IVM). Immunofluorescence assay showed that Survivin-depleted oocytes failed to produce polar body in meiosisⅠ (failed to complete cytokinesis), and they were arrested in metaphaseⅠwith misaligned chromosomes. The homologous chromosomes in Survivin-depleted oocytes could not be separated normally. Moreover, both the phosphorylation levels of Aurora B and the mRNA level of Mad2L1 related to spindle assembly checkpoint (SAC) was decreased in Survivin-depleted oocytes, which thus inhibited the degradation of Cyclin B1 (CCNB1) to complete meiosis. Taken together, we conclude that Survivin is an important mediator of centromere and midbody docking of Aurora-B as well as its activity and regulates SAC and MPF activity during meiosis in porcine oocytes.

Genetic Interactions between the Aurora Kinases Reveal New Requirements for AURKB and AURKC during Oocyte Meiosis

Errors in chromosome segregation during female meiosis I occur frequently, and aneuploid embryos account for 1/3 of all miscarriages in humans [1]. Unlike mitotic cells that require two Aurora kinase (AURK) homologs to help prevent aneuploidy (AURKA and AURKB), mammalian germ cells also require a third (AURKC) [2, 3]. AURKA is the spindle-pole-associated homolog, and AURKB/C are the chromosome-localized homologs. In mitosis, AURKB has essential roles as the catalytic subunit of the chromosomal passenger complex (CPC), regulating chromosome alignment, kinetochore-microtubule attachments, cohesion, the spindle assembly checkpoint, and cytokinesis [4, 5]. In mouse oocyte meiosis, AURKC takes over as the predominant CPC kinase [6], although the requirement for AURKB remains elusive [7]. In the absence of AURKC, AURKB compensates, making defining potential non-overlapping functions difficult [6, 8]. To investigate the role(s) of AURKB and AURKC in oocytes, we analyzed oocyte-specific Aurkb and Aurkc single- and double-knockout (KO) mice. Surprisingly, we find that double KO female mice are fertile. We demonstrate that, in the absence of AURKC, AURKA localizes to chromosomes in a CPC-dependent manner. These data suggest that AURKC prevents AURKA from localizing to chromosomes by competing for CPC binding. This competition is important for adequate spindle length to support meiosis I. We also describe a unique requirement for AURKB to negatively regulate AURKC to prevent aneuploidy. Together, our work reveals oocyte-specific roles for the AURKs in regulating each other's localization and activity. This inter-kinase regulation is critical to support wild-type levels of fecundity in female mice.

In vitro and in vivo antimelanoma effect of ethyl ester cyclohexyl analog of ethylenediamine dipropanoic acid

Melanoma, an aggressive skin tumor with high metastatic potential, is associated with high mortality and increasing morbidity. Multiple available chemotherapeutic and immunotherapeutic modalities failed to improve survival in advanced disease, and the search for new agents is ongoing. The aim of this study was to investigate antimelanoma effects of O,O-diethyl-(S,S)-ethylenediamine-N,N'di-2-(3-cyclohexyl) propanoate dihydrochloride (EE), a previously synthesized and characterized organic compound. Mouse melanoma B16 cell viability was assessed using acid phosphatase, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, sulforhodamine B, and lactate dehydrogenase assays. Apoptosis and autophagy were investigated using flow cytometry, fluorescence and electron microscopy, and western blotting. In vivo antitumor potential was assessed in subcutaneous mouse melanoma model after 14 days of treatment with EE. Tumor mass and volume were measured, and RT-PCR was used for investigating the expression of autophagy-related, proapoptotic, and antiapoptotic molecules in tumor tissue. Investigated organic compound exerts significant cytotoxic effect against B16 cells. EE induced apoptosis, as confirmed by phosphatidyl serine externalisation, caspase activation, and ultrastructural features typical for apoptosis seen on fluorescence and electron microscopes. The apoptotic mechanism included prompt disruption of mitochondrial membrane potential and oxidative stress. No autophagy was observed. Antimelanoma action and apoptosis induction were confirmed in vivo, as EE decreased mass and volume of tumors, and increased expression of several proapoptotic genes. EE possesses significant antimelanoma action and causes caspase-dependent apoptosis mediated by mitochondrial damage and reactive oxygen species production. Decrease in tumor growth and increase in expression of proapoptotic genes in tumor tissue suggest that EE warrants further investigation as a candidate agent in treating melanoma.

Theoretical study of the intermolecular recognition mechanism between Survivin and substrate based on conserved binding mode analysis

Survivin is the smallest member of IAP (inhibitor of apoptosis protein) family, which plays important roles in both mitosis and apoptosis. It has become an attractive drug target due to its overexpression in many human cancers. Survivin has been proven to bind to Smac/DIABLO protein that indirectly inhibits apoptosis. Meanwhile, it is the key subunit of chromosome passenger complex (CPC) which bind to the N-terminal tail of phosphorylated histone H3T3ph during mitosis. Up to now, Survivin directly targeting inhibitor has yet to merge since the difficulty of disrupting the protein-protein interactions (PPIs) between Survivin and its substrate proteins. Nevertheless, currently known binding partners of Survivin provide crucial information about conserved recognition mechanism, which can assist in the detection of some uncharted substrates and also the Survivin inhibitors. Herein, we adopted a method that using four substrates to analyze the common binding mode of Survivin. To accomplish this, conventional molecular dynamics (MD) simulations, molecular mechanics/generalized born surface area (MM-GBSA) binding free energy calculations and energy decomposition were carried out to assess the binding affinity and per-residue contributions. We found that there are two anchor sites of Survivin responsible for maintaining the binding conformation and one sub-pocket for intermolecular recognition. The results of this study synthetically describe the binding mechanism and provide valuable guidance for rational drug design of PPI inhibitor.

Knockdown of survivin results in inhibition of epithelial to mesenchymal transition in retinal pigment epithelial cells by attenuating the TGFβ pathway

Proliferative vitreoretinopathy (PVR) is a common complication of open globe injury and the most common cause of failed retinal detachment surgery. The response by retinal pigment epithelial (RPE) cells liberated into the vitreous includes proliferation and migration; most importantly, epithelial to mesenchymal transition (EMT) of RPE plays a central role in the development and progress of PVR. For the first time, we show that knockdown of BIRC5, a member of the inhibitor of apoptosis protein family, using either lentiviral vector based CRISPR/Cas9 nickase gene editing or inhibition of survivin using the small-molecule inhibitor YM155, results in the suppression of EMT in RPE cells. Knockdown of survivin or inhibition of survivin significantly reduced TGFβ-induced cell proliferation and migration. We further demonstrated that knockdown or inhibition of survivin attenuated the TGFβ signaling by showing reduced phospho-SMAD2 in BIRC5 knockdown or YM155-treated cells compared to controls. Inhibition of the TGFβ pathway using TGFβ receptor inhibitor also suppressed survivin expression in RPE cells. Our studies demonstrate that survivin contributes to EMT by cross-talking with the TGFβ pathway in RPE cells. Targeting survivin using small-molecule inhibitors may provide a novel approach to treat PVR disease.

Microarray analysis reveals Tmub1 as a cell cycle-associated protein in rat hepatocytes

Transmembrane and ubiquitin-like domain containing protein 1 (Tmub1), formerly known as hepatocyte odd protein shuttling (HOPS) has been recognized as a ubiquitously expressed shuttling protein that moves between the nucleus and cytoplasm in hepatocytes. Tmub1 is involved in liver regeneration and functions as a bridging protein in tumor cell proliferation. To investigate the transcriptional profile and potential biological processes affected by Tmub1 expression in normal rat hepatocytes, microarray and bioinformatics experiments were used to identify 127 mRNAs differentially expressed between Tmub1-overexpression, Tmub1-knockdown and normal BRL-3A cells (fold-change ≥2.5). The expression levels of 17 key node genes associated with the cell cycle were confirmed by reverse transcription-quantitative polymerase chain reaction analysis. Flow cytometry, 5-Ethynyl-20-deoxyuridine, Cell Counting Kit-8 and western blotting experiments revealed the effects on the cell cycle and the inhibition of proliferation in BRL-3A cells overexpressing Tmub1. Further co-immunoprecipitation assays demonstrated that Tmub1 interacts with cyclin A2 during the cell cycle and that the overexpression of Tmub1 may postpone cyclin A2 and cyclin B1 degradation in the M phase. The results of the present study indicated that Tmub1 functions as a cell proliferation inhibitor and cell cycle-associated protein.

Identification of genes that are essential to restrict genome duplication to once per cell division

Nuclear genome duplication is normally restricted to once per cell division, but aberrant events that allow excess DNA replication (EDR) promote genomic instability and aneuploidy, both of which are characteristics of cancer development. Here we provide the first comprehensive identification of genes that are essential to restrict genome duplication to once per cell division. An siRNA library of 21,584 human genes was screened for those that prevent EDR in cancer cells with undetectable chromosomal instability. Candidates were validated by testing multiple siRNAs and chemical inhibitors on both TP53+ and TP53- cells to reveal the relevance of this ubiquitous tumor suppressor to preventing EDR, and in the presence of an apoptosis inhibitor to reveal the full extent of EDR. The results revealed 42 genes that prevented either DNA re-replication or unscheduled endoreplication. All of them participate in one or more of eight cell cycle events. Seventeen of them have not been identified previously in this capacity. Remarkably, 14 of the 42 genes have been shown to prevent aneuploidy in mice. Moreover, suppressing a gene that prevents EDR increased the ability of the chemotherapeutic drug Paclitaxel to induce EDR, suggesting new opportunities for synthetic lethalities in the treatment of human cancers.

Chromosomal instability induced by increased BIRC5/Survivin levels affects tumorigenicity of glioma cells

Background

Survivin, belonging to the inhibitor of apoptosis (IAP) gene family, is abundantly expressed in tumors. It has been hypothesized that Survivin facilitates carcinogenesis by inhibition of apoptosis resulting in improved survival of tumorigenic progeny. Additionally, Survivin plays an essential role during mitosis. Together with its molecular partners Aurora B, Borealin and inner centromere protein it secures bipolar chromosome segregation. However, whether increased Survivin levels contribute to progression of tumors by inducing chromosomal instability remains unclear.

Methods

We overexpressed Survivin in U251-MG, SVGp12, U87-MG, HCT116 and p53-deficient U87-MG^shp53 and HCT116^p53−/− cells. The resulting phenotype was investigated by FACS-assisted cell cycle analysis, Western Blot analysis, confocal laser scan microscopy, proliferation assays, spectral karyotyping and in a U251-MG xenograft model using immune-deficient mice.

Results

Overexpression of Survivin affected cells with knockdown of p53, cells harboring mutant p53 and SV40 large T antigen, respectively, resulting in the increase of cell fractions harboring 4n and >4n DNA contents. Increased γH2AX levels, indicative of DNA damage were monitored in all Survivin-transduced cell lines, but only in p53 wild type cells this was accompanied by an attenuated S-phase entry and activation of p21^waf/cip. Overexpression of Survivin caused a DNA damage response characterized by increased appearance pDNA-PKcs foci in cell nuclei and elevated levels of pATM S1981 and pCHK2 T68. Additionally, evolving structural chromosomal aberrations in U251-MG cells transduced with Survivin indicated a DNA-repair by non-homologous end joining recombination. Subcutaneous transplantation of U251-MG cells overexpressing Survivin and mycN instead of mycN oncogene alone generated tumors with shortened latency and decreased apoptosis. Subsequent SKY-analysis of Survivin/mycN-tumors revealed an increase in structural chromosomal aberrations in cells when compared to mycN-tumors.

Conclusions

Our data suggest that increased Survivin levels promote adaptive evolution of tumors through combining induction of genetic heterogeneity with inhibition of apoptosis.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3932-y) contains supplementary material, which is available to authorized users.

The Ins and Outs of Aurora B Inner Centromere Localization

Error-free chromosome segregation is essential for the maintenance of genomic integrity during cell division. Aurora B, the enzymatic subunit of the Chromosomal Passenger Complex (CPC), plays a crucial role in this process. In early mitosis Aurora B localizes predominantly to the inner centromere, a specialized region of chromatin that lies at the crossroads between the inter-kinetochore and inter-sister chromatid axes. Two evolutionarily conserved histone kinases, Haspin and Bub1, control the positioning of the CPC at the inner centromere and this location is thought to be crucial for the CPC to function. However, recent studies sketch a subtler picture, in which not all functions of the CPC require strict confinement to the inner centromere. In this review we discuss the molecular pathways that direct Aurora B to the inner centromere and deliberate if and why this specific localization is important for Aurora B function.

Subcellular Localization of Survivin Determines Its Function in Cardiomyocytes

Rationale:Reducing cardiomyocyte death and enhancing their proliferation after myocardial infarction is perhaps the single largest challenge for cardiac tissue regeneration. Survivin (SVV) is the smallest member of the inhibitor of apoptosis (IAP) family but plays two important roles; inhibiting caspase-9 activation in the intrinsic apoptosis pathway, and regulating microtubule dynamics and chromosome segregation during cell division. Genetic depletion of cardiac SVV leads to incomplete cardiomyocyte division and abnormal heart development. However, the function of SVV in adult hearts after myocardial infarction remains unclear.

Methods: A homozygous inducible cardiomyocyte-specific SVV knockout transgenic mouse model was established through crossbreeding SVV^flox/flox and αMHC-MCM transgenic mice. Adult mice received consecutive intraperitoneal injection of tamoxifen to induce genetic removal of SVV in cardiomyocytes. A SVV overexpressing model was established via local delivery of SVV in wild-type mouse hearts.

Results: We found that 30.82% of cardiomyocytes in the peri-infarct region of SVV knockout mice were apoptotic, significantly higher than the 22.18% in control mice. In addition, ejection fraction was 29.00±0.40% in knockout mice compared to 38.04±0.50% in control mice 21 days after myocardial infarction. On the contrary, locally overexpressing SVV in the heart improved cardiac functions. Unexpectedly, we found that altering the subcellular localization of SVV overexpression produced different outcomes. Overexpression of SVV in the cytoplasm decreased cardiomyocyte apoptosis, whereas overexpression of SVV in the nucleus enhanced cardiac regeneration. The ejection fraction of mice overexpressing SVV was 36.58±0.91%, significantly higher than 28.18±1.70% in the GFP control group. Apoptotic cardiomyocytes were only 4.63% in mouse overexpressing cytosolic SVV, compared to 9.31% in the GFP group, and activation of caspase-3 was also reduced. Moreover, mice overexpressing NLS-SVV exhibited a better ejection fraction (36.19±1.02%,) than GFP controls (26.69±0.75%). NLS-SVV enhanced H3P-positive cardiomyocytes in the border zone to 0.28%, compared to only 0.08% in GFP group, through interacting with Aurora B.

Conclusions:We demonstrate the importance of SVV subcellular localization in regulating post-MI cardiac repair and regeneration. We hope that this will open new translational approaches through targeted delivery of SVV.

Microplate magnetic chemiluminescence immunoassay for detecting urinary survivin in bladder cancer

Survivin is a tumor marker for bladder cancer; however the role of urinary survivin levels has not been fully elucidated due to the limitations of current detection methods. Based on two survivin-specific monoclonal antibodies (McAbs) already confirmed through enzyme linked immunosorbent assays, the present study aimed to establish a microplate magnetic chemiluminescence immunoassay (CLIA) for the detection of urinary survivin levels and evaluate its application for the diagnosis of patients with bladder cancer. Horseradish peroxidase and biotin conjugates were used to label two different anti-survivin McAbs, respectively. The labeled antibodies combined with survivin to form a sandwiched immune complex. The streptavidin magnetic particles (MPs) served as the solid phase and the separator. The relevant parameters involved in the immunoassay, including the immunoassay reagents used and the physicochemical parameters were optimized. Then, urine samples from 130 patients with bladder cancer and 113 healthy controls were detected, and analyzed using the established method. The method was linear to 1,000 ng/ml survivin with a detection limit of 0.83 ng/ml. The intra- and inter-assay coefficients of variation were <8, and <11%, respectively. The concentration of diluted survivin and the dilution ratios gave a linear correlation of 0.9989. The results demonstrated that the urinary survivin levels in patients with bladder cancer were significantly higher (P<0.001) compared with that in healthy controls. At a survivin concentration of 2.0884 ng/ml, the sensitivity and specificity were 86.9 and 61.9%, respectively. Furthermore, the urinary survivin levels were positively correlated with metastatic stage, histological stage and recurrence (P<0.01). In conclusion, the present study preliminarily proposed a microplate magnetic CLIA for survivin detection and further evaluated the value of urinary survivin as a diagnostic marker for bladder cancer.

Inducing death in tumor cells: roles of the inhibitor of apoptosis proteins

The heterogeneous group of diseases collectively termed cancer results not just from aberrant cellular proliferation but also from a lack of accompanying homeostatic cell death. Indeed, cancer cells regularly acquire resistance to programmed cell death, or apoptosis, which not only supports cancer progression but also leads to resistance to therapeutic agents. Thus, various approaches have been undertaken in order to induce apoptosis in tumor cells for therapeutic purposes. Here, we will focus our discussion on agents that directly affect the apoptotic machinery itself rather than on drugs that induce apoptosis in tumor cells indirectly, such as by DNA damage or kinase dependency inhibition. As the roles of the Bcl-2 family have been extensively studied and reviewed recently, we will focus in this review specifically on the inhibitor of apoptosis protein (IAP) family. IAPs are a disparate group of proteins that all contain a baculovirus IAP repeat domain, which is important for the inhibition of apoptosis in some, but not all, family members. We describe each of the family members with respect to their structural and functional similarities and differences and their respective roles in cancer. Finally, we also review the current state of IAPs as targets for anti-cancer therapeutics and discuss the current clinical state of IAP antagonists.

Survivin, a molecular target for therapeutic interventions in squamous cell carcinoma

Squamous cell carcinoma (SCC) is the most common cancer worldwide. The treatment of locally advanced disease generally requires various combinations of radiotherapy, surgery, and systemic therapy. Despite aggressive multimodal treatment, most of the patients relapse. Identification of molecules that sustain cancer cell growth and survival has made molecular targeting a feasible therapeutic strategy. Survivin is a member of the Inhibitor of Apoptosis Protein (IAP) family, which is overexpressed in most of the malignancies including SCC and totally absent in most of the normal tissues. This feature makes survivin an ideal target for cancer therapy. It orchestrates several important mechanisms to support cancer cell survival including inhibition of apoptosis and regulation of cell division. Overexpression of survivin in tumors is also associated with poor prognosis, aggressive tumor behavior, resistance to therapy, and high tumor recurrence. Various strategies have been developed to target survivin expression in cancer cells, and their effects on apoptosis induction and tumor growth attenuation have been demonstrated. In this review, we discuss recent advances in therapeutic potential of survivin in cancer treatment.

Links between DNA Replication, Stem Cells and Cancer

Cancers can be categorized into two groups: those whose frequency increases with age, and those resulting from errors during mammalian development. The first group is linked to DNA replication through the accumulation of genetic mutations that occur during proliferation of developmentally acquired stem cells that give rise to and maintain tissues and organs. These mutations, which result from DNA replication errors as well as environmental insults, fall into two categories; cancer driver mutations that initiate carcinogenesis and genome destabilizing mutations that promote aneuploidy through excess genome duplication and chromatid missegregation. Increased genome instability results in accelerated clonal evolution leading to the appearance of more aggressive clones with increased drug resistance. The second group of cancers, termed germ cell neoplasia, results from the mislocation of pluripotent stem cells during early development. During normal development, pluripotent stem cells that originate in early embryos give rise to all of the cell lineages in the embryo and adult, but when they mislocate to ectopic sites, they produce tumors. Remarkably, pluripotent stem cells, like many cancer cells, depend on the Geminin protein to prevent excess DNA replication from triggering DNA damage-dependent apoptosis. This link between the control of DNA replication during early development and germ cell neoplasia reveals Geminin as a potential chemotherapeutic target in the eradication of cancer progenitor cells.

GRIM-19: A master regulator of cytokine induced tumor suppression, metastasis and energy metabolism

Cytokines induce cell proliferation or growth suppression depending on the context. It is increasingly becoming clear that success of standard radiotherapy and/or chemotherapeutics to eradicate solid tumors is dependent on IFN signaling. In this review we discuss the molecular mechanisms of tumor growth suppression by a gene product isolated in our laboratory using a genome-wide expression knock-down strategy. Gene associated with retinoid-IFN-induced mortality -19 (GRIM-19) functions as non-canonical tumor suppressor by antagonizing oncoproteins. As a component of mitochondrial respiratory chain, GRIM-19 influences the degree of "Warburg effect" in cancer cells as many advanced and/or aggressive tumors show severely down-regulated GRIM-19 levels. In addition, GRIM-19 appears to regulate innate and acquired immune responses in mouse models. Thus, GRIM-19 is positioned at nodes that favor cell protection and/or prevent aberrant cell growth.

Hepatic Loss of Borealin Impairs Postnatal Liver Development, Regeneration, and Hepatocarcinogenesis

Borealin, a member of the chromosomal passenger complex, plays a key regulatory role at centromeres and the central spindle during mitosis. Loss of Borealin leads to defective cell proliferation and early embryonic lethality. The in vivo functions of Borealin in mammalian postnatal development, tissue homeostasis, and tumorigenesis remain elusive. We specifically analyzed the role of Borealin in regulating postnatal liver development, damage-induced liver regeneration, and liver carcinogenesis using mice carrying conditional Borealin alleles. Perinatal loss of Borealin caused increased genome ploidy and enlarged cell size in hepatocytes, likely due to the impaired function of the chromosomal passenger complex in mitosis. Borealin deletion also showed attenuated expansion of Sox9⁺HNF4α⁺ progenitor-like cells in liver regeneration during 3,5-diethoxycarbonyl-1,4-dihydrocollidine diet-induced liver injury. Moreover, ΔN90-β-Catenin and c-Met-induced hepatocarcinogenesis development was largely impeded by Borealin deletion. These findings indicate that Borealin plays a key role in liver development, regeneration, and tumorigenesis and suggests that Borealin could be a potential target for related liver diseases.

A new survivin tracer tracks, delocalizes and captures endogenous survivin at different subcellular locations and in distinct organelles

Survivin, the smallest member of the inhibitor of apoptosis protein family, plays a central role during mitosis and exerts a cytoprotective function. Survivin is highly expressed in most cancer types and contributes to multiple facets of carcinogenesis. The molecular mechanisms underlying its highly diverse functions need to be extensively explored, which is crucial for rational design of future personalized therapeutics. In this study, we have generated an alpaca survivin nanobody (SVVNb8) that binds with low nanomolar affinity to its target. When expressed as an intrabody in HeLa cells, SVVNb8 faithfully tracks survivin during different phases of mitosis without interfering with survivin function. Furthermore, coupling SVVNb8 with a subcellular delocalization tag efficiently redirects endogenous survivin towards the nucleus, the cytoplasm, peroxisomes and even to the intermembrane space of mitochondria where it presumably interacts with resident mitochondrial survivin. Based on our findings, we believe that SVVNb8 is an excellent instrument to further elucidate survivin biology and topography, and can serve as a model system to investigate mitochondrial and peroxisomal (survivin) protein import.