Tankyrase-Binding Protein TNKS1BP1 Regulates Actin Cytoskeleton Rearrangement and Cancer Cell Invasion

Therapeutic targeting of TNIK in papillary thyroid carcinoma: a novel approach for tumor growth suppression

Papillary thyroid carcinoma (PTC) is a common endocrine malignancy. The pathology of PTC is far from clear. As a kinase that can be targeted, the role of TNIK in PTC has not been investigated. This study was focused on the effects and molecular mechanisms of TNIK in PTC. Both public datasets and clinical specimens were used to verify TNIK expression. The effects of TNIK were investigated in both cell lines and mice models. Transcriptome analysis was used to explore the underlying mechanism of TNIK. Immunofluorescence, wound healing, and qRT-PCR assays were used to validate the mechanism of TNIK in PTC. The therapeutic effects of TNIK inhibitor NCB-0846 were evaluated by flow cytometry, western blot, and subcutaneous xenografts mice. TNIK expression was upregulated in PTC tissues. TNIK knockdown could suppress cell proliferation and tumor growth in no matter cell models or nude mice. The transcriptome analysis, GO enrichment analysis, and GSEA analysis results indicated TNIK was highly correlated with cytoskeleton, cell motility, and Wnt pathways. The mechanistic studies demonstrated that TNIK regulated cytoskeleton remodeling and promoted cell migration. NCB-0846 significantly inhibited TNIK kinase activity, induced cell apoptosis, and activated apoptosis-related proteins in a dose-dependent manner. In addition, NCB-0846 inhibited tumor growth in tumor-bearing mice. In summary, we proposed a novel regulatory mechanism in which TNIK-mediated cytoskeleton remodeling and cell migration to regulate tumor progression in PTC. TNIK is a therapeutic target in PTC and NCB-0846 would act as a novel targeted drug for PTC therapy.

TAB182 regulates glycolytic metabolism by controlling LDHA transcription to impact tumor radiosensitivity

Metabolic reprogramming, a hallmark of cancer, is closely associated with tumor development and progression. Changes in glycolysis play a crucial role in conferring radiation resistance to tumor cells. How radiation changes the glycolysis status of cancer cells is still unclear. Here we revealed the role of TAB182 in regulating glycolysis and lactate production in cellular response to ionizing radiation. Irradiation can significantly stimulate the production of TAB182 protein, and inhibiting TAB182 increases cellular radiosensitivity. Proteomic analysis indicated that TAB182 influences several vital biological processes, including multiple metabolic pathways. Knockdown of TAB182 results in decreased lactate production and increased pyruvate and ATP levels in cancer cells. Moreover, knocking down TAB182 reverses radiation-induced metabolic changes, such as radioresistant-related lactate production. TAB182 is necessary for activating LDHA transcription by affecting transcription factors SP1 and c-MYC; its knockdown attenuates the upregulation of LDHA by radiation, subsequently suppressing lactate production. Targeted suppression of TAB182 significantly enhances the sensitivity of murine xenograft tumors to radiotherapy. These findings advance our understanding of glycolytic metabolism regulation in response to ionizing radiation, which may offer significant implications for developing new strategies to overcome tumor radioresistance.

APC/PIK3CA mutations and β-catenin status predict tankyrase inhibitor sensitivity of patient-derived colorectal cancer cells

BACKGROUND

Aberrant WNT/β-catenin signaling drives carcinogenesis. Tankyrases poly(ADP-ribosyl)ate and destabilize AXINs, β-catenin repressors. Tankyrase inhibitors block WNT/β-catenin signaling and colorectal cancer (CRC) growth. We previously reported that 'short' APC mutations, lacking all seven β-catenin-binding 20-amino acid repeats (20-AARs), are potential predictive biomarkers for CRC cell sensitivity to tankyrase inhibitors. Meanwhile, 'Long' APC mutations, which possess more than one 20-AAR, do not predict inhibitor-resistant cells. Thus, additional biomarkers are needed to precisely predict the inhibitor sensitivity.

METHODS

Using 47 CRC patient-derived cells (PDCs), we examined correlations between the sensitivity to tankyrase inhibitors (G007-LK and RK-582), driver mutations, and the expressions of signaling factors. NOD.CB17-Prkdcscid/J and BALB/c-nu/nu xenograft mice were treated with RK-582.

RESULTS

Short APC mutant CRC cells exhibited high/intermediate sensitivities to tankyrase inhibitors in vitro and in vivo. Active β-catenin levels correlated with inhibitor sensitivity in both short and long APC mutant PDCs. PIK3CA mutations, but not KRAS/BRAF mutations, were more frequent in inhibitor-resistant PDCs. Some wild-type APC PDCs showed inhibitor sensitivity in a β-catenin-independent manner.

CONCLUSIONS

APC/PIK3CA mutations and β-catenin predict the sensitivity of APC-mutated CRC PDCs to tankyrase inhibitors. These observations may help inform the strategy of patient selection in future clinical trials of tankyrase inhibitors.

Downregulation of TAB182 promotes cancer stem-like cell properties and therapeutic resistance in triple-negative breast cancer cells

TAB182 participates in DNA damage repair and radio-/chemosensitivity regulation in various tumors, but its role in tumorigenesis and therapeutic resistance in breast cancer remains unclear. In the current paper, we observed that triple-negative Breast Cancer (TNBC), a highly aggressive type of breast cancer, exhibits a lower expression of TAB182. TAB182 knockdown stimulates the proliferation, migration, and invasion of TNBC cells. Our study first obtained RNA-seq data to explore the cellular functions mediated by TAB182 at the genome level in TNBC cells. A transcriptome analysis and in vitro experiments enabled us to identify that TAB182 downregulation drives the enhanced properties of cancer stem-like cells (CSCs) in TNBC cells. Furthermore, TAB182 deletion contributes to the resistance of cells to olaparib or cisplatin, which can be rescued by silencing GLI2, a gene downstream of cancer stemness-related signaling pathways. Our results reveal a novel function of TAB182 as a potential negative regulator of cancer stem-like properties and drug sensitivity in TNBC cells, suggesting that TAB182 may be a tumor suppressor gene and is associated with increased therapeutic benefits for TNBC patients.

Paxillin interactome identified by SILAC and label-free approaches coupled to TurboID sheds light on the compositions of focal adhesions in mouse embryonic stem cells

Self-renewal and differentiation of mouse embryonic stem cells (mESCs) are greatly affected by the extracellular matrix (ECM) environment; the composition and stiffness of which are sensed by the cells via integrin-associated focal adhesions (FAs) which link the cells to the ECM. Although FAs have been studied extensively in differentiated cells, their composition and function in mESCs are not as well elucidated. To gain more detailed knowledge of the molecular compositions of FAs in mESCs, we adopted the proximity-dependent biotinylation (BioID) proteomics approach. Paxillin, a known FA protein (FAP), is fused to the promiscuous biotin ligase TurboID as bait. We employed both SILAC- and label-free (LF)-based quantitative proteomics to strengthen as well as complement individual approach. The mass spectrometry data derived from SILAC and LF identified 38 and 443 proteins, respectively, with 35 overlapping candidates. Fifteen of these shared proteins are known FAPs based on literature-curated adhesome and 7 others are among the reported "meta-adhesome", suggesting the components of FAs are largely conserved between mESCs and differentiated cells. Furthermore, the LF data set contained an additional 18 literature-curated FAPs. Notably, the overlapped proteomics data failed to detect LIM-domain proteins such as zyxin family proteins, which suggests that FAs in mESCs are less mature than differentiated cells. Using the LF approach, we are able to identify PDLIM7, a LIM-domain protein, as a FAP in mESCs. This study illustrates the effectiveness of TurboID in mESCs. Importantly, we found that application of both SILAC and LF methods in combination allowed us to analyze the TurboID proteomics data in an unbiased, stringent and yet comprehensive manner.

Nitidine chloride regulates cell function of bladder cancer in vitro through downregulating Lymphocyte antigen 75

Nitidine chloride (NC) is effective on cancer in many tumors, but its effect on bladder cancer (BC) is unknown. We conducted cell function experiments to verify the antineoplastic effect of NC on BC cell lines (5637, T24, and UM-UC-3) in vitro. Then, mRNAs of NC-treated and NC-untreated BC cells were extracted for mRNA sequencing. Differentially expressed genes (DEGs), expression analysis, and drug molecular docking were conducted to discover the target gene of NC. Finally, functional enrichment was analyzed to explore the underlying mechanisms. NC dramatically inhibited proliferation, migration, and invasion, and it induced apoptosis and arrested the S and G2/M phases of BC cell lines. Lymphocyte antigen 75 (LY75) appeared to be the target of NC. LY75 was highly expressed and had the ability to distinguish BC tissue from non-cancerous tissue. Then, drug molecular docking confirmed the targeting relationship between NC and LY75. Gene enrichment analysis showed that the downregulated genes, after being treated with NC, were mainly enriched in pathways relevant to cell pathophysiological processes. NC inhibits BC cell proliferation, migration, and invasion, induces apoptosis, and arrests cell cycles by downregulating the expression of LY75. This study provides molecular and theoretical bases for NC treatment of BC.

The Cell Biology of Metastatic Invasion in Pancreatic Cancer: Updates and Mechanistic Insights

Pancreatic ductal adenocarcinoma (PDAC) is one of the leading causes of cancer-related mortality worldwide. This is largely due to the lack of routine screening protocols, an absence of symptoms in early-stage disease leading to late detection, and a paucity of effective treatment options. Critically, the majority of patients either present with metastatic disease or rapidly develop metastatic disease. Thus, there is an urgent need to deepen our understanding of metastasis in PDAC. During metastasis, tumor cells escape from the primary tumor, enter the circulation, and travel to a distant site to form a secondary tumor. In order to accomplish this relatively rare event, tumor cells develop an enhanced ability to detach from the primary tumor, migrate into the surrounding matrix, and invade across the basement membrane. In addition, cancer cells interact with the various cell types and matrix proteins that comprise the tumor microenvironment, with some of these factors working to promote metastasis and others working to suppress it. In PDAC, many of these processes are not well understood. The purpose of this review is to highlight recent advances in the cell biology of the early steps of the metastatic cascade in pancreatic cancer. Specifically, we will examine the regulation of epithelial-to-mesenchymal transition (EMT) in PDAC and its requirement for metastasis, summarize our understanding of how PDAC cells invade and degrade the surrounding matrix, and discuss how migration and adhesion dynamics are regulated in PDAC to optimize cancer cell motility. In addition, the role of the tumor microenvironment in PDAC will also be discussed for each of these invasive processes.

BioID2 screening identifies KIAA1671 as an EPS8 proximal factor that marks sites of microvillus growth

Microvilli are defining morphological features of the apical surfaces in diverse epithelial tissues. To develop our understanding of microvillus biogenesis, we used a biotin proximity-labeling approach to uncover new molecules enriched near EPS8, a well-studied marker of the microvillus distal tip compartment. Mass spectrometry of biotinylated hits identified KIAA1671, a large (∼200 kDa), disordered, and previously uncharacterized protein. Based on immunofluorescent staining and expression of fluorescent protein-tagged constructs, we found that KIAA1671 localizes to the base of the brush border in native intestinal tissue and polarized epithelial-cell culture models, as well as dynamic actin-rich structures in unpolarized, nonepithelial cell types. Live imaging also revealed that during the early stages of microvillar growth, KIAA1671 colocalizes with EPS8 in diffraction-limited puncta. However, once elongation of the core bundle begins, these two factors separate, with EPS8 tracking the distal end and KIAA1671 remaining behind at the base of the structure. These results suggest that KIAA1671 cooperates with EPS8 and potentially other assembly factors to initiate growth of microvilli on the apical surface. These findings offer new details on how transporting epithelial cells builds the brush border and may inform our understanding of how apical specializations are assembled in other epithelial contexts.

Silencing TAB182 inhibits cell EMT, migration and invasion by downregulating EGFR in A549 NSCLC cells

BACKGROUND

TAB182 is overexpressed in cancerous tissues and correlated with poor overall survival in lung cancer patients. Mechanistically, TAB182 participates in DNA damage repair and endows tumour cells with radio- and chemoresistance. However, its role in non-small cell lung cancer (NSCLC) remains unclear.

METHODS AND RESULTS

Cells with stable TAB182 knockdown (KD) were generated using A549 NSCLC cells, and we demonstrated that depleting TAB182 inhibits cell EMT, proliferation, colony formation, migration and invasion. Analysis of the TCGA database showed a positive correlation between TAB182 and EGFR, a well-established NSCLC oncoprotein. Then, we verified that silencing TAB182 decreases EGFR expression at both the mRNA and protein levels. Moreover, both TAB182 and EGFR were reported to restore ionizing radiation (IR)-triggered DNA damage. We validated that IR elevates the protein level of EGFR and that silencing TAB182 can alleviate IR-induced EGFR upregulation. Furthermore, overexpressing EGFR abrogates the inhibitory effects of TAB182 KD on EMT, migration, and invasion in A549 cells.

CONCLUSIONS

Our data demonstrated that EGFR expression is regulated by TAB182 and downregulation of TAB182 has a novel function to repress EMT, migration and invasion by decreasing EGFR, indicating TAB182 could regulate the malignant progression of NSCLC.

TAB182 aggravates progression of esophageal squamous cell carcinoma by enhancing β-catenin nuclear translocation through FHL2 dependent manner

TAB182 (also named TNKS1BP1), a binding protein of tankyrase 1, has been found to participate in DNA repair. Our previous study has revealed the involvement of TAB182 in the radioresistance of esophageal squamous cell carcinoma (ESCC) cells. However, whether TAB182 contributes to the ESCC tumorigenesis and progression remains unclear. In this study, we found that highly expressed TAB182 is closely associated with a poor prognosis of patients with ESCC. TAB182 silencing reduced ESCC cell proliferation and invasion in vitro, tumorigenicity and metastasis in vivo. RNA-seq and IP-MS analysis revealed that TAB182 could affect the β-catenin signaling pathway via interacting with β-catenin. Furthermore, TAB182 prevented β-catenin to be phosphorylated by GSK3β and recruited four and a half of LIM-only protein 2 (FHL2), which thereby promoted β-catenin nucleus translocation to result in activation of the downstream targets transcription in ESCC cells. Our findings demonstrate that TAB182 enhances tumorigenesis of esophageal cancer by promoting the activation of the β-catenin signaling pathway, which provides new insights into the molecular mechanisms by which TAB182 accelerates progression of ESCC.

Changes of Protein Expression after CRISPR/Cas9 Knockout of miRNA-142 in Cell Lines Derived from Diffuse Large B-Cell Lymphoma

Simple Summary

The gene of the human tumor suppressive microRNA-142 (miR-142) carries mutations in about 20% of cases of diffuse large B-cell lymphoma (DLBCL). Because microRNAs post-transcriptionally regulate the protein expression of their cognate messenger RNA (mRNAs) targets, we determined the effect of miR-142 knockout on protein expression in two cell lines derived from DLBCL. We found a significant up-regulation of 52 proteins but also a down-regulation of 41 proteins upon miR-142 deletion. Knockout of a miRNA may be used to identify novel targets, and seed-sequence mutants of a miRNA unable to bind to their targets can be used to confirm potential novel targets. With this approach, we identify AKT1S1, CCNB1, LIMA1 and TFRC as novel targets of miR-142. As miR-142 is highly present in the miRNA processing RISC complexes, the deletion of this miRNA might result in its replacement by other miRNAs, thus introducing an additional layer of complexity regarding gene regulation.

Abstract

Background: As microRNA-142 (miR-142) is the only human microRNA gene where mutations have consistently been found in about 20% of all cases of diffuse large B-cell lymphoma (DLBCL), we wanted to determine the impact of miR-142 inactivation on protein expression of DLBCL cell lines. Methods: miR-142 was deleted by CRISPR/Cas9 knockout in cell lines from DLBCL. Results: By proteome analyses, miR-142 knockout resulted in a consistent up-regulation of 52 but also down-regulation of 41 proteins in GC-DLBCL lines BJAB and SUDHL4. Various mitochondrial ribosomal proteins were up-regulated in line with their pro-tumorigenic properties, while proteins necessary for MHC-I presentation were down-regulated in accordance with the finding that miR-142 knockout mice have a defective immune response. CFL2, CLIC4, STAU1, and TWF1 are known targets of miR-142, and we could additionally confirm AKT1S1, CCNB1, LIMA1, and TFRC as new targets of miR-142-3p or -5p. Conclusions: Seed-sequence mutants of miR-142 confirmed potential targets and novel targets of miRNAs can be identified in miRNA knockout cell lines. Due to the complex contribution of miRNAs within cellular regulatory networks, in particular when miRNAs highly present in RISC complexes are replaced by other miRNAs, primary effects on gene expression may be covered by secondary layers of regulation.

Defining the Dynamic Regulation of O-GlcNAc Proteome in the Mouse Cortex---the O-GlcNAcylation of Synaptic and Trafficking Proteins Related to Neurodegenerative Diseases

O-linked conjugation of ß-N-acetyl-glucosamine (O-GlcNAc) to serine and threonine residues is a post-translational modification process that senses nutrient availability and cellular stress and regulates diverse biological processes that are involved in neurodegenerative diseases and provide potential targets for therapeutics development. However, very little is known of the networks involved in the brain that are responsive to changes in the O-GlcNAc proteome. Pharmacological increase of protein O-GlcNAcylation by Thiamet G (TG) has been shown to decrease tau phosphorylation and neurotoxicity, and proposed as a therapy in Alzheimer’s disease (AD). However, acute TG exposure impairs learning and memory, and protein O-GlcNAcylation is increased in the aging rat brain and in Parkinson’s disease (PD) brains. To define the cortical O-GlcNAc proteome that responds to TG, we injected young adult mice with either saline or TG and performed mass spectrometry analysis for detection of O-GlcNAcylated peptides. This approach identified 506 unique peptides corresponding to 278 proteins that are O-GlcNAcylated. Of the 506 unique peptides, 85 peptides are elevated by > 1.5 fold in O-GlcNAcylation levels in response to TG. Using pathway analyses, we found TG-dependent enrichment of O-GlcNAcylated synaptic proteins, trafficking, Notch/Wnt signaling, HDAC signaling, and circadian clock proteins. Significant changes in the O-GlcNAcylation of DNAJC6/AUXI, and PICALM, proteins that are risk factors for PD and/or AD respectively, were detected. We compared our study with two key prior O-GlcNAc proteome studies using mouse cerebral tissue and human AD brains. Among those identified to be increased by TG, 15 are also identified to be increased in human AD brains compared to control, including those involved in cytoskeleton, autophagy, chromatin organization and mitochondrial dysfunction. These studies provide insights regarding neurodegenerative diseases therapeutic targets.

A Novel Ferroptosis-Related Gene Signature to Predict Prognosis of Esophageal Carcinoma

Objective

This study aimed to develop a novel ferroptosis-related gene-based prognostic signature for esophageal carcinoma (ESCA).

Methods

The TCGA-ESCA gene expression profiles and corresponding clinical data were downloaded from the TCGA database. Ferroptosis-related genes were identified from the literature and public databases, which were intersected with the differentially expressed genes between ESCA and normal samples. After univariate Cox regression and random forest analyses, several ferroptosis-related feature genes were identified and used to construct a prognostic signature. Then, the prognostic value of the complex value and the correlation of the complex value with immune cell infiltration were analyzed. Moreover, function analysis, mutation analysis, and molecular docking on the ferroptosis-related feature genes were performed.

Results

Based on the TCGA dataset and ferroptosis pathway genes, 1929 ferroptosis-related genes were preliminarily selected. Following univariate Cox regression analysis and survival analysis, 14 genes were obtained. Then, random forest analysis identified 10 ferroptosis key genes. These 10 genes were used to construct a prognostic complex value. It was found that low complex value indicated better prognosis compared with high complex value. In different ESCA datasets, there were similar differences in the proportion of immune cell distribution between the high and low complex value groups. Furthermore, TNKS1BP1, AC019100.7, KRI1, BCAP31, and RP11-408E5.5 were significantly correlated with ESCA tumor location, lymph node metastasis, and age of patients. KRI1 had the highest mutation frequency. BCAP31 had the strongest binding ability with small molecules DB12830, DB05812, and DB07307.

Conclusion

We constructed a novel ferroptosis-related gene signature, which has the potential to predict patient survival and tumor-infiltrating immune cells of ESCA.

Rare protein-coding variants implicate genes involved in risk of suicide death

Identification of genetic factors leading to increased risk of suicide death is critical to combat rising suicide rates, however, only a fraction of the genetic variation influencing risk has been accounted for. To address this limitation, we conducted the first comprehensive analysis of rare genetic variation in suicide death leveraging the largest suicide death biobank, the Utah Suicide Genetic Risk Study (USGRS). We conducted a single-variant association analysis of rare (minor allele frequency <1%) putatively functional single-nucleotide polymorphisms (SNPs) present on the Illumina PsychArray genotyping array in 2,672 USGRS suicide deaths of non-Finnish European (NFE) ancestry and 51,583 NFE controls from the Genome Aggregation Database. Secondary analyses used an independent control sample of 21,324 NFE controls from the Psychiatric Genomics Consortium. Five novel, high-impact, rare SNPs were identified with significant associations with suicide death (SNAPC1, rs75418419; TNKS1BP1, rs143883793; ADGRF5, rs149197213; PER1, rs145053802; and ESS2, rs62223875). 119 suicide decedents carried these high-impact SNPs. Both PER1 and SNAPC1 have other supporting gene-level evidence of suicide risk, and psychiatric associations exist for PER1 (bipolar disorder, schizophrenia), and for TNKS1BP1 and ESS2 (schizophrenia). Three of the genes (PER1, TNKS1BP1, and ADGRF5), together with additional genes implicated by genome-wide association studies on suicidal behavior, showed significant enrichment in immune system, homeostatic and signal transduction processes. No specific diagnostic phenotypes were associated with the subset of suicide deaths with the identified rare variants. These findings suggest an important role for rare variants in suicide risk and implicate genes and gene pathways for targeted replication.

Effect of p53 and its N-terminally truncated isoform, Δ40p53, on breast cancer migration and invasion

Breast cancer is the most diagnosed malignancy in women, with over half a million women dying from this disease each year. In our previous studies, ∆40p53, an N‐terminally truncated p53 isoform, was found to be upregulated in breast cancers, and a high ∆40p53 : p53α ratio was linked with worse disease‐free survival. Although p53α inhibits cancer migration and invasion, little is known about the role of ∆40p53 in regulating these metastasis‐related processes and its role in contributing to worse prognosis. The aim of this study was to assess the role of ∆40p53 in breast cancer migration and invasion. A relationship between Δ40p53 and gene expression profiles was identified in oestrogen‐receptor‐positive breast cancer specimens. To further evaluate the role of Δ40p53 in oestrogen‐receptor‐positive breast cancer, MCF‐7 and ZR75‐1 cell lines were transduced to knockdown p53α or Δ40p53 and overexpress Δ40p53. Proliferation, migration and invasion were assessed in the transduced sublines, and gene expression was assessed through RNA‐sequencing and validated by reverse‐transcription quantitative PCR. Knockdown of both p53α and ∆40p53 resulted in increased proliferation, whereas overexpression of ∆40p53 reduced proliferation rates. p53α knockdown was also associated with increased cell mobility. ∆40p53 overexpression reduced both migratory and invasive properties of the transduced cells. Phenotypic findings are supported by gene expression data, including differential expression of LRG1, HYOU1, UBE2QL1, SERPINA5 and PCDH7. Taken together, these results suggest that, at the basal level, ∆40p53 works similarly to p53α in suppressing cellular mobility and proliferation, although the role of Δ40p53 may be cell context‐specific.

ERK1/2: An Integrator of Signals That Alters Cardiac Homeostasis and Growth

Integration of cellular responses to extracellular cues is essential for cell survival and adaptation to stress. Extracellular signal-regulated kinase (ERK) 1 and 2 serve an evolutionarily conserved role for intracellular signal transduction that proved critical for cardiomyocyte homeostasis and cardiac stress responses. Considering the importance of ERK1/2 in the heart, understanding how these kinases operate in both normal and disease states is critical. Here, we review the complexity of upstream and downstream signals that govern ERK1/2-dependent regulation of cardiac structure and function. Particular emphasis is given to cardiomyocyte hypertrophy as an outcome of ERK1/2 activation regulation in the heart.

Arpin Regulates Migration Persistence by Interacting with Both Tankyrases and the Arp2/3 Complex

During cell migration, protrusion of the leading edge is driven by the polymerization of Arp2/3-dependent branched actin networks. Migration persistence is negatively regulated by the Arp2/3 inhibitory protein Arpin. To better understand Arpin regulation in the cell, we looked for its interacting partners and identified both Tankyrase 1 and 2 (TNKS) using a yeast two-hybrid screening and coimmunoprecipitation with full-length Arpin as bait. Arpin interacts with ankyrin repeats of TNKS through a C-terminal-binding site on its acidic tail, which overlaps with the Arp2/3-binding site. Arpin was found to dissolve the liquid–liquid phase separation of TNKS upon overexpression. To uncouple the interactions of Arpin with TNKS and Arp2/3, we introduced point mutations in the Arpin tail and attempted to rescue the increased migration persistence of the Arpin knockout cells using random plasmid integration or compensating knock-ins at the ARPIN locus. Arpin mutations impairing interactions with either Arp2/3 or TNKS were insufficient to fully abolish Arpin activity. Only the mutation that affected both interactions rendered Arpin completely inactive, suggesting the existence of two independent pathways, whereby Arpin controls the migration persistence.

Elevated TAB182 enhances the radioresistance of esophageal squamous cell carcinoma through G2-M checkpoint modulation

Background

Radiotherapy is one of the main strategies for the treatment of esophageal squamous cell carcinoma (ESCC). However, treatment failure often occurs due to the emergence of radioresistance. In this study, we report a key regulator of radiation sensitivity, termed TAB182 that may become an ideal biomarker and therapeutic target to overcome radioresistance.

Materials and Methods

By applying qRT‐PCR and immunohistochemical staining, the expression of TAB182 was detected in patient tissues. We next assessed the influence of TAB182 downregulation to radiosensitivity using clonogenic survival assay and γ‐H2A.X foci analysis in TE‐1, TE‐10, and radioresistant TE‐1R cell lines after ionizing radiation. To unveil the mechanism underlying, TAB182 interacting proteins were identified by mass spectrometry following co‐immunoprecipitation. Furthermore, flow cytometry and western blot assay were applied to validate the identified proteins.

Results

Our results demonstrated that the expression of TAB182 is higher in cancer tissues than normal tissues and elevated expression of TAB182 correlates with poor outcomes of postoperative radiotherapy. Downregulation of TAB182 sensitized cancer cells to ionizing radiation, particularly in radioresistant TE‐1R cells that spontaneously overexpress TAB182. Mechanically, TAB182 interacts with FHL2 to induce G2‐M arrest through wiring the CHK2/CDC25C/CDC2 signaling pathway. Finally, overexpression of shRNA‐resistant TAB182 restored the checkpoint and radioresistance.

Conclusion

TAB182 potentiates the radioresistance of ESCC cells by modulating the G2‐M checkpoint through its interaction with FHL2. Thus, TAB182 may become an ideal biomarker and therapeutic target of ESCC radiotherapy.

PIM1 accelerates prostate cancer cell motility by phosphorylating actin capping proteins

Background

The PIM family kinases promote cancer cell survival and motility as well as metastatic growth in various types of cancer. We have previously identified several PIM substrates, which support cancer cell migration and invasiveness. However, none of them are known to regulate cellular movements by directly interacting with the actin cytoskeleton. Here we have studied the phosphorylation-dependent effects of PIM1 on actin capping proteins, which bind as heterodimers to the fast-growing actin filament ends and stabilize them.

Methods

Based on a phosphoproteomics screen for novel PIM substrates, we have used kinase assays and fluorescence-based imaging techniques to validate actin capping proteins as PIM1 substrates and interaction partners. We have analysed the functional consequences of capping protein phosphorylation on cell migration and adhesion by using wound healing and real-time impedance-based assays. We have also investigated phosphorylation-dependent effects on actin polymerization by analysing the protective role of capping protein phosphomutants in actin disassembly assays.

Results

We have identified capping proteins CAPZA1 and CAPZB2 as PIM1 substrates, and shown that phosphorylation of either of them leads to increased adhesion and migration of human prostate cancer cells. Phosphorylation also reduces the ability of the capping proteins to protect polymerized actin from disassembly.

Conclusions

Our data suggest that PIM kinases are able to induce changes in actin dynamics to support cell adhesion and movement. Thus, we have identified a novel mechanism through which PIM kinases enhance motility and metastatic behaviour of cancer cells.

Identification and analysis of dysregulated lncRNA and associated ceRNA in the pathogenesis of keloid

Background

Keloid is an excessive fibrosis disease caused by the abnormal proliferation of collagen fibers following trauma. Previous studies have shown that genetic factors have been considered to play important roles in keloid formation. This study is aimed to investigate the regulatory network of messenger RNAs (mRNAs) microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) in keloid, and identifying its key biomarkers.

Methods

We performed RNA-seq and miRNA-seq on keloid and normal skin samples. Sequencing datasets were analyzed by bioinformatics. Gene ontology (GO) and pathway analysis presented the characteristics of associated protein-coding genes. Differentially expressed ceRNAs were validated by quantitative reverse transcriptase-PCR (qRT-PCR).

Results

We identified a total of 319 lncRNAs, 1,533 mRNAs and 40 miRNAs as keloid-specific RNAs. Both the GO biological processes and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were analyzed for 1,219 specific genes with differentially expressed mRNAs. Then, with 509 key lncRNAs, 25 miRNAs, and 94 mRNAs, we constructed a ceRNA network and explored any potential underlying mechanisms. In the regulation of the actin cytokeleton pathway, we validated 2 pairs of ceRNAs EGFR/miR-370-3p/lnc-GLB1L-1 and ITGB5/ miR-204/ lnc-CASP9-3 in another sample size in keloid.

Conclusions

Through RNA-seq and miRNA-seq, we identified keloid-associated lncRNAs, mRNAs and miRNAs, which can be used as potential therapeutic targets and biomarkers for keloid. Our study may lay a foundation for future pathogenesis studies.

Tankyrase Inhibitors Target Colorectal Cancer Stem Cells via AXIN-Dependent Downregulation of c-KIT Tyrosine Kinase

Cancer stem cells (CSC) constitute heterogeneous cell subpopulations of a tumor. Although targeting CSCs is important for cancer eradication, no clinically approved drugs that target CSCs have been established. Tankyrase poly(ADP-ribosyl)ates and destabilizes AXIN, a negative regulator of β-catenin, and promotes β-catenin signaling. Here, we report that tankyrase inhibitors downregulate c-KIT tyrosine kinase and inhibit the growth of CD44-positive colorectal CSCs. c-KIT expression in CD44-positive subpopulations of colorectal cancer COLO-320DM cells is associated with their tumor-initiating potential in vivo Tankyrase inhibitors downregulate c-KIT expression in established cell lines, such as COLO-320DM and DLD-1, and colorectal cancer patient-derived cells. These effects of tankyrase inhibitors are caused by reducing the recruitment of SP1 transcription factor to the c-KIT gene promoter and depend on AXIN2 stabilization but not β-catenin downregulation. Whereas c-KIT knockdown inhibits the growth of CD44-positive COLO-320DM cells, c-KIT overexpression in DLD-1 cells confers resistance to tankyrase inhibitors. Combination of a low-dose tankyrase inhibitor and irinotecan significantly inhibited the growth of COLO-320DM tumors in a mouse xenograft model. These observations suggest that tankyrase inhibitors target c-KIT-positive colorectal CSCs and provide a novel therapeutic strategy for cancer.

Platelet ATP, Thyroid Hormone Receptor on Integrin αvβ3 and Cancer Metastasis

Activated platelets may contribute to the metastatic behavior of tumor cells when the cancer cells and platelets interact. The interaction requires cell and platelet surface integrin. Thyroid hormone as L-thyroxine (T4) is the principal ligand for a hormone receptor on integrin αvβ3 on tumor cells and platelets. T4 activates the integrin, promoting platelet aggregation and degranulation (local ATP release) and stimulating tumor cell proliferation. By a variety of molecular mechanisms reviewed here, extracellular ATP promotes tumor cell invasiveness and metastasis and supports a role for T4 as a pro-metastatic factor.

Tankyrase promotes primary precursor miRNA processing to precursor miRNA

Tankyrases (TNKS and TNKS2) are members of poly(ADP-ribose) polymerase (PARP) family proteins. Tankyrase has multiple ankyrin repeat cluster (ARC) domains, which recognize the tankyrase-binding motifs in proteins including the telomeric protein, TRF1 and Wnt signal regulators, AXINs. However, the functional significance of tankyrase interaction with many other putative binding proteins remains unknown. Here, we found that several proteins involved in microRNA (miRNA) processing have putative tankyrase-binding motifs and their functions are regulated by tankyrase. First, chemical inhibition of tankyrase PARP activity downregulated the expression levels of precursor miRNAs (pre-miRNAs) but not primary precursor miRNAs (pri-miRNAs). A subsequent reporter assay revealed that tankyrase inhibitors or PARP-dead mutant tankyrase overexpression repress pri-miRNA processing to pre-miRNA. Conversely, a PARP-1/2 inhibitor, olaparib, did not affect pri-miRNA processing. Tankyrase ARCs bound to DGCR8 and DROSHA, which are essential components for pri-miRNA processing and have putative tankyrase-binding motifs. These observations indicate that tankyrase binds to Microprocessor, DGCR8 and DROSHA complex and modulates pri-miRNA processing to pre-miRNA.

Identifying Mutually Exclusive Gene Sets with Prognostic Value and Novel Potential Driver Genes in Patients with Glioblastoma

The pathogenesis and prognosis of glioblastoma (GBM) remain poorly understood. Mutual exclusivity analysis can distinguish driver genes and pathways from passenger ones. The purpose of this study was to identify mutually exclusive gene sets (MEGSs) that have prognostic value and to detect novel driver genes in GBM. The genomic alteration profile and clinical information were derived from The Cancer Genome Atlas, and the MEGSA method was used to identify the MEGS. Next, we performed survival analysis and constructed a risk prediction model for prognostic stratification. Leave-one-out cross-validation and permutation test were used to evaluate its performance. Finally, we identified 21 statistically significant MEGSs. We found that the MEGS in the RB pathway was significantly associated with poor prognosis, after adjusting for age and gender (HR = 1.837, 95% CI: 1.192-2.831). Based on the risk prediction model, 208 (80.9%) and 49 (19.1%) patients were assigned to high- and low-risk groups, respectively (log-rank: p < 0.001, adjusted p=0.001). Additionally, we found that SPTA1, a novel gene involved in the MEGS, was mutually exclusive with members of cell cycle, P53, and RB pathways. In conclusion, the MEGS in the RB pathway had considerable clinical value for GBM prognostic stratification. Mutated SPTA1 may be involved in GBM development.

Comprehensive circular RNA profiling reveals the regulatory role of the hsa_circ_0137606/miR‑1231 pathway in bladder cancer progression

Bladder cancer (BC) is one of the most common malignant tumors in males globally. Its progression imposes a heavy burden on patients; however, the expression profile of circular (circ)RNAs in BC progression remains unclear. This study explored changes in circRNA expression during BC progression by sequencing different grade BC samples and normal controls to reveal the circRNA expression profiles of different BC grades. Gene Ontology (GO) and Kyoto Encyclopedia of Gens and Genomes (KEGG) pathway analyses, and protein-protein interaction network construction were used to predict pathways that the differentially expressed circRNAs may participate in. circRNA expression levels were detected using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and dual-luciferase reporter assays were used to investigate the interactions between circRNA and microRNA (miR). Cell Counting Kit-8 and Transwell assays were also performed to detect cell proliferation, migration, and invasion. In total, 244 circRNAs were found to be differentially expressed in high-grade BC compared to low-grade BC, whilst 316 dysregulated circRNAs were detected in high-grade BC compared with normal urothelium. Furthermore, 42 circRNAs overlapped between the two groups, seven of which were randomly selected and detected by RT-qPCR to validate the sequencing results. GO analysis and KEGG pathway analyses revealed that the differentially expressed circRNAs may participate in BC via 'GTPase activity regulation', 'cell junction', and 'focal adhesion' pathways. Of note, we proposed that a novel circRNA in BC progression, hsa_circ_0137606, could suppress BC proliferation and metastasis by sponging miR-1231. Through bioinformatics analysis, we predicted that PH domain and leucine rich repeat protein phosphatase 2 could be a target of the hsa_circ_0137606/miR-1231 axis in BC progression. Using high-throughput sequencing, this study revealed the circRNA expression profiles of different grades of BC and proposed that the novel circRNA, hsa_circ_0137606, suppresses BC proliferation and metastasis by sponging miR-1231. Our findings may provide novel insight into potential therapeutic targets for treating BC.

DEAD-box helicase eIF4A2 inhibits CNOT7 deadenylation activity

The CCR4-NOT complex plays an important role in the translational repression and deadenylation of mRNAs. However, little is known about the specific roles of interacting factors. We demonstrate that the DEAD-box helicases eIF4A2 and DDX6 interact directly with the MA3 and MIF domains of CNOT1 and compete for binding. Furthermore, we now show that incorporation of eIF4A2 into the CCR4-NOT complex inhibits CNOT7 deadenylation activity in contrast to DDX6 which enhances CNOT7 activity. Polyadenylation tests (PAT) on endogenous mRNAs determined that eIF4A2 bound mRNAs have longer poly(A) tails than DDX6 bound mRNAs. Immunoprecipitation experiments show that eIF4A2 does not inhibit CNOT7 association with the CCR4-NOT complex but instead inhibits CNOT7 activity. We identified a CCR4-NOT interacting factor, TAB182, that modulates helicase recruitment into the CCR4-NOT complex, potentially affecting the outcome for the targeted mRNA. Together, these data show that the fate of an mRNA is dependent on the specific recruitment of either eIF4A2 or DDX6 to the CCR4-NOT complex which results in different pathways for translational repression and mRNA deadenylation.

MERIT40-dependent recruitment of tankyrase to damaged DNA and its implication for cell sensitivity to DNA-damaging anticancer drugs

Tankyrase, a member of the poly(ADP-ribose) polymerase (PARP) family, regulates various intracellular responses, such as telomere maintenance, Wnt/β-catenin signaling and cell cycle progression through its interactions with multiple target proteins. Tankyrase contains a long stretch of 24 ankyrin repeats that are further divided into five subdomains, called ANK repeat clusters (ARCs). Each ARC works as an independent ligand-binding unit, which implicates tankyrase as a platform for multiple protein-protein interactions. Furthermore, tankyrase distributes to various intracellular loci, suggesting potential distinct but yet unidentified physiological functions. To explore the novel functions of tankyrase, we performed liquid chromatography-mass spectrometry analysis and identified the BRE-BRCC36-MERIT40 complex, a regulator of homologous recombination, as tankyrase-binding proteins. Among the complex components, MERIT40 was directly associated with tankyrase via a tankyrase-binding consensus motif, as previously reported. In X-ray-irradiated non-small cell lung cancer cells, tankyrase localized to DNA double-stranded break sites in a MERIT40-dependent manner. MERIT40 knockdown increased the cell sensitivity to X-ray, whereas the wild-type, but not the tankyrase-unbound mutant, MERIT40 rescued the phenotype of the knockdown cells. Tankyrase inhibitors, such as G007-LK and XAV939, increased the cellular sensitivity to X-ray irradiation and anticancer drugs that induce DNA double-stranded breaks. These observations suggest that tankyrase plays a role in the DNA damage repair response and implicates a potential therapeutic utility of tankyrase inhibitors in combination treatments with DNA-damaging anticancer drugs.

Degradation of a Novel DNA Damage Response Protein, Tankyrase 1 Binding Protein 1, following Adenovirus Infection

Infection by most DNA viruses activates a cellular DNA damage response (DDR), which may be to the detriment or advantage of the virus. In the case of adenoviruses, they neutralize antiviral effects of DDR activation by targeting a number of proteins for rapid proteasome-mediated degradation. We have now identified a novel DDR protein, tankyrase 1 binding protein 1 (TNKS1BP1) (also known as Tab182), which is degraded during infection by adenovirus serotype 5 and adenovirus serotype 12. In both cases, degradation requires the action of the early region 1B55K (E1B55K) and early region 4 open reading frame 6 (E4orf6) viral proteins and is mediated through the proteasome by the action of cullin-based cellular E3 ligases. The degradation of Tab182 appears to be serotype specific, as the protein remains relatively stable following infection with adenovirus serotypes 4, 7, 9, and 11. We have gone on to confirm that Tab182 is an integral component of the CNOT complex, which has transcriptional regulatory, deadenylation, and E3 ligase activities. The levels of at least 2 other members of the complex (CNOT3 and CNOT7) are also reduced during adenovirus infection, whereas the levels of CNOT4 and CNOT1 remain stable. The depletion of Tab182 with small interfering RNA (siRNA) enhances the expression of early region 1A proteins (E1As) to a limited extent during adenovirus infection, but the depletion of CNOT1 is particularly advantageous to the virus and results in a marked increase in the expression of adenovirus early proteins. In addition, the depletion of Tab182 and CNOT1 results in a limited increase in the viral DNA level during infection. We conclude that the cellular CNOT complex is a previously unidentified major target for adenoviruses during infection.

IMPORTANCE Adenoviruses target a number of cellular proteins involved in the DNA damage response for rapid degradation. We have now shown that Tab182, which we have confirmed to be an integral component of the mammalian CNOT complex, is degraded following infection by adenovirus serotypes 5 and 12. This requires the viral E1B55K and E4orf6 proteins and is mediated by cullin-based E3 ligases and the proteasome. In addition to Tab182, the levels of other CNOT proteins are also reduced during adenovirus infection. Thus, CNOT3 and CNOT7, for example, are degraded, whereas CNOT4 and CNOT1 are not. The siRNA-mediated depletion of components of the complex enhances the expression of adenovirus early proteins and increases the concentration of viral DNA produced during infection. This study highlights a novel protein complex, CNOT, which is targeted for adenovirus-mediated protein degradation. To our knowledge, this is the first time that the CNOT complex has been identified as an adenoviral target.