ABI3 ectopic expression reduces in vitro and in vivo cell growth properties while inducing senescence

CBLC promotes the development of colorectal cancer by promoting ABI1 degradation to activate the ERK signaling pathway

CBLC (CBL proto-oncogene C) is an E3 ubiquitin protein ligase that plays a key role in cancers. However, the function and mechanism of CBLC in colorectal cancer (CRC) has not been fully elucidated. The aim of this study was to investigate the function of CBLC in CRC and its underlying molecular mechanism. High CBLC levels were certified in tumor tissues of CRC patients, and its expression was positively associated with TNM stage. Next, we explored the role of CBLC in CRC using gain or loss of function. For biological function analysis, CCK-8 cell proliferation, colony formation, flow cytometry, scratch, and transwell assays collectively suggested that CBLC overexpression promoted cell proliferation, cell cycle progression, migration and invasion. As observed, CBLC knockdown exhibited exactly opposite effects, resulting in impaired tumorigenicity in vitro. Xenograft studies displayed that CBLC overexpression accelerated tumor growth and promoted tumor metastasis to the lung, while the inhibitory effects of CBLC knockdown on tumorigenicity and metastasis ability of CRC cells was also confirmed. Furthermore, the molecular mechanism of CBLC in CRC was explored. CBLC induced the activation of ERK signaling pathway, further leading to its pro-tumor role. Notably, CBLC decreased ABI1 (Abelson interactor protein-1, a candidate tumor suppressor) protein levels through its ubiquitin ligase activity, while ABI1 upregulation abolished the effects of CBLC on the tumorigenesis of CRC. Taken together, these results demonstrate that CBLC acts as a tumor promoter in CRC through triggering the ubiquitination and degradation of ABI1 and activating the ERK signaling pathway. CBLC may be a potential novel target for CRC.

The Role of Methylation in Chronic Lymphocytic Leukemia and Its Prognostic and Therapeutic Impacts in the Disease: A Systematic Review

Epigenetic regulation has been thoroughly investigated in recent years and has emerged as an important aspect of chronic lymphocytic leukemia (CLL) biology. Characteristic aberrant features such as methylation patterns and global DNA hypomethylation were the early findings of the research during the last decades. The investigation in this field led to the identification of a large number of genes where methylation features correlated with important clinical and laboratory parameters. Gene-specific analyses investigated methylation in the gene body enhancer regions as well as promoter regions. The findings included genes and proteins involved in key pathways that play central roles in the pathophysiology of the disease. Τhe application of these findings beyond the theoretical understanding can not only lead to the creation of prognostic and predictive models and scores but also to the design of novel therapeutic agents. The following is a review focusing on the present knowledge about single gene/gene promoter methylation or mRNA expression in CLL cases as well as records of older data that have been published in past papers.

Comprehensive pan-cancer investigation: unraveling the oncogenic, prognostic, and immunological significance of Abelson interactor family member 3 gene in human malignancies

Background: Abelson interactor Family Member 3 (ABI3) encodes protein that not only suppresses the ectopic metastasis of tumor cells but also hinders their migration. Although ABI3 had been found to modulate the advancement of diverse neoplasms, there is no comprehensive pan-cancer analysis of its effects. Methods: The transcriptomics data of neoplasm and normal tissues were retrieved from the Genomic Data Commons (GDC) data portal, and UCSC XENA database. To gather protein information for ABI3, Human Protein Atlas (HPA) and GeneMANIA websites were utilized. Additionally, Tumor Immune Single-cell Hub (TISCH) database was consulted to determine the primary cell types expressing ABI3 in cancer microenvironments. Univariate Cox regression approach was leveraged to evaluate ABI3's prognostic role across cancers. The Cbioportal and Gene Set Cancer Analysis (GSCA) website were leveraged to scrutinize the genomic landscape information across cancers. TIMER2.0 was leveraged to probe the immune cell infiltrations associated with ABI3 across cancers. The associations of ABI3 with immune-related genes were analyzed through Spearman correlation method. Gene Set Enrichment Analysis (GSEA) and Gene Set Variation Analysis (GSVA) were utilized to search associated biological pathways. The CellMiner database and molecular docking were implemented to identify potential interactions between the ABI3 protein and specific anticarcinogen. Findings: ABI3 expression and its ability to predict prognosis varied distinct tumor, with particularly high expression observed in Tprolif cells and monocytes/macrophages. Copy number variation (CNV) and methylation negatively correlated with ABI3 expression in the majority of malignancies. Corresponding mutation survival analysis indicated that the mutation status of ABI3 was strongly connected to the prognosis of LGG patients. ABI3 expression was linked to immunotherapeutic biomarkers and response in cancers. ESTIMATE and immune infiltrations analyses presented ABI3 association with immunosuppression. ABI3 was significantly correlated with immunoregulators and immune-related pathways. Lastly, prospective ABI3-targeted drugs were filtered and docked to ABI3 protein. Interpretation: Our study reveals that ABI3 acts as a robust tumor biomarker. Its functions are vital that could inhibit ectopic metastasis of tumor cells and modulate cellular adhesion and migration. The discoveries presented here may have noteworthy consequences for the creation of fresh anticancer suppressors, especially those targeting BRCA.

The entanglement of extracellular matrix molecules and immune checkpoint inhibitors in cancer: a systematic review of the literature

Introduction

Immune-checkpoint inhibitors (ICIs) have emerged as a core pillar of cancer therapy as single agents or in combination regimens both in adults and children. Unfortunately, ICIs provide a long-lasting therapeutic effect in only one third of the patients. Thus, the search for predictive biomarkers of responsiveness to ICIs remains an urgent clinical need. The efficacy of ICIs treatments is strongly affected not only by the specific characteristics of cancer cells and the levels of immune checkpoint ligands, but also by other components of the tumor microenvironment, among which the extracellular matrix (ECM) is emerging as key player. With the aim to comprehensively describe the relation between ECM and ICIs' efficacy in cancer patients, the present review systematically evaluated the current literature regarding ECM remodeling in association with immunotherapeutic approaches.

Methods

This review followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines and was registered at the International Prospective Register of Systematic Reviews (PROSPERO, CRD42022351180). PubMed, Web of Science, and Scopus databases were comprehensively searched from inception to January 2023. Titles, abstracts and full text screening was performed to exclude non eligible articles. The risk of bias was assessed using the QUADAS-2 tool.

Results

After employing relevant MeSH and key terms, we identified a total of 5070 studies. Among them, 2540 duplicates, 1521 reviews or commentaries were found and excluded. Following title and abstract screening, the full text was analyzed, and 47 studies meeting the eligibility criteria were retained. The studies included in this systematic review comprehensively recapitulate the latest observations associating changes of the ECM composition following remodeling with the traits of the tumor immune cell infiltration. The present study provides for the first time a broad view of the tight association between ECM molecules and ICIs efficacy in different tumor types, highlighting the importance of ECM-derived proteolytic products as promising liquid biopsy-based biomarkers to predict the efficacy of ICIs.

Conclusion

ECM remodeling has an important impact on the immune traits of different tumor types. Increasing evidence pinpoint at ECM-derived molecules as putative biomarkers to identify the patients that would most likely benefit from ICIs treatments.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022351180, identifier CRD42022351180.

A cellular senescence-related genes model allows for prognosis and treatment stratification of cervical cancer: a bioinformatics analysis and external verification

BACKGROUND

Cervical cancer (CC) is highly lethal and aggressive with an increasing trend of mortality for females. Molecular characterization-based methods hold great promise for improving the diagnostic accuracy and for predicting treatment response.

METHODS

The mRNAs expression data of CC patients and cellular senescence-related genes were obtained from the Cancer Genome Atlas (TCGA) and CellAge databases, respectively. Differentially expressed genes (DEGs) of senescence related genes between tumor and normal tissues were used for Least absolute shrinkage and selection operator (LASSO) regression to construct a prognostic model. Univariate and LASSO regression analyses were applied to establish a predictive nomogram. The performance of the nomogram were evaluated by Kaplan-Meier curve, receiver operating characteristic (ROC), Harrell's concordance index (C-index), and calibration curve. GSE44001 and GSE52903 were used for external validation.

RESULTS

We established a cellular senescence-related genes-based stratified model, and a multivariable-based nomogram, which could accurately predict the prognosis of CC patients in the TCGA database. The Kaplan-Meier curve indicated that patients in the low-risk group had considerably better overall survival (OS, P =2.021e-05). The area under the ROC curve (AUC) of this model was 0.743 for OS. Multivariate analysis found that the 6-gene risk signature (HR=3.166, 95%CI: 1.660-6.041, P<0.001) was an independent risk factor for CC patients. We then designed an OS-associated nomogram that included the risk signature and clinicopathological factors. The AUC reached 0.860 for predicting 5-year OS. The nomogram showed excellent consistency between the predictions and actual survival observations. Two external GEO validations were corresponding to the gene expression pattern in TCGA.

CONCLUSIONS

Our results suggested a six-senescence related signature and established a prognostic nomogram that reliably predicted the overall survival for CC. These findings may be beneficial to personalized treatment and medical decision-making.

Role of Human Monocarboxylate Transporter 1 (hMCT1) and 4 (hMCT4) in Tumor Cells and the Tumor Microenvironment

In recent years, the abnormal glucose metabolism of tumor cells has attracted increasing attention. Abnormal glucose metabolism is closely related to the occurrence and development of tumors. Monocarboxylate transporters (MCTs) transport the sugar metabolites lactic acid and pyruvate, which affect glucose metabolism and tumor progression in a variety of ways. Thus, research has recently focused on MCTs and their potential functions in cancer. The MCT superfamily consists of 14 members. MCT1 and MCT4 play a crucial role in the maintenance of intracellular pH in tumor cells by transporting monocarboxylic acids (such as lactate, pyruvate and butyrate). MCT1 and MCT4 are highly expressed in a variety of tumor cells and are involved the proliferation, invasion and migration of tumor cells, which are closely related to the prognosis of cancer. Because of their important functions in tumor cells, MCT1 and MCT4 have become potential targets for cancer treatment. In this review, we focus on the structure, function and regulation of MCT1 and MCT4 and discuss the developed inhibitors of MCT1 and MCT4 to provide more comprehensive information that might aid in the development of strategies targeting MCTs in cancer.

FAT10 Induces cancer cell migration by stabilizing phosphorylated ABI3/NESH

The WAVE regulatory complex (WRC) is involved in various cellular processes by regulating actin polymerization. The dysregulation of WRC components is associated with cancer development. ABI family member 3 (ABI3)/new molecule including SH3 (NESH) is one of the WRC components and it has been reported that ABI3 phosphorylation can affect WRC function. Although several residues of ABI3 have been reported to be possible phosphorylation sites, it is still unclear which residues are important for the function of ABI3. Furthermore, it is unclear how the phosphorylated form of ABI3 is regulated. Here, we demonstrate that ABI3 is stabilized by its interaction with human leukocyte antigen-F adjacent transcript 10 (FAT10). Using phospho-dead or phospho-mimetic mutants of ABI3, we showed that serine 213 and 216 are important phosphorylation sites of ABI3. In particular, FAT10 has a higher affinity for the phosphorylated form of ABI3 than the non-phosphorylated form, and it stabilizes the phosphorylated form more than the non-phosphorylated form through this differential affinity. The interaction between FAT10 and the phosphorylated form of ABI3 promoted cancer cell migration. Therefore, our results suggest that FAT10 stabilizes the phosphorylated form of ABI3, which may lead to WRC activation, thereby promoting cancer cell migration.

A Potential Four-Gene Signature and Nomogram for Predicting the Overall Survival of Papillary Thyroid Cancer

Background. Although the prognosis of papillary thyroid cancer (PTC) is relatively good, some patients experience recurrence or distant metastasis after thyroidectomy and progress to radioactive iodine refractory stage. Therefore, accurate prediction of clinical outlook can aid to screen out the minority of patients with poorer prognosis and avoid excessive treatment in low-risk patients. Methods. The RNA-seq and clinical data of PTC patients was downloaded from the Gene Expression Omnibus (GEO) and the Cancer Genome Atlas (TCGA) databases. Multivariate and Lasso Cox regression analyses were used to construct a prognostic nomogram to predict overall survival (OS). Thereafter, quantitative RT-PCR and Human Protein Atlas (HPA) database were employed to verify the expression of key genes. Results. A four-gene risk score comprising ABI3BP, DPT, MRO, and TENM1 was exhibited strong prognostic value. Moreover, an integrated nomogram was established based on the risk score, age, AJCC (American Joint Commission on Cancer) stage, tumor size, extrathyroidal extension, and history of neoadjuvant treatment, which exhibited significantly better predictive performance than TNM stage system ( $P<0.05$ ). GSEA (Gene Set Enrichment Analysis) and GSVA (Gene Set Variation Analysis) revealed that the different tumor-associated hallmarks, biological processes, and pathways were substantially enriched in the poor-prognosis group. In addition, a ceRNA network was constructed by including the four genes (ABI3BP, DPT, MRO, and TENM1), 54 lncRNAs, and 10 miRNAs. Finally, both the relative mRNA and protein expression of ABI3BP, DPT, MRO, and TENM1 were validated. Conclusion. The present study identified a four-gene risk signature and developed a novel nomogram, which could be regarded as a reliable prognostic model for PTC patients. The findings also revealed preliminary potential mechanisms that may influence the prognosis outcome. These results can be conducive to design personalized treatment and prognosis management in affected patients.

Hookah Smoke Mediates Cancer-Associated Epigenomic and Transcriptomic Signatures in Human Respiratory Epithelial Cells

Introduction

Although communal smoking of hookah by means of water pipes is perceived to be a safe alternative to cigarette smoking, the effects of hookah smoke in respiratory epithelia have not been well characterized. This study evaluated epigenomic and transcriptomic effects of hookah smoke relative to cigarette smoke in human respiratory epithelial cells.

Methods

Primary normal human small airway epithelial cells from three donors and cdk4 and hTERT-immortalized small airway epithelial cells and human bronchial epithelial cells were cultured for 5 days in normal media with or without cigarette smoke condensates (CSCs) or water pipe condensates (WPCs). Cell count, immunoblot, RNA sequencing, quantitative real-time reverse-transcriptase polymerase chain reaction, methylation-specific polymerase chain reaction, and quantitative chromatin immunoprecipitation techniques were used to compare effects of hookah and cigarette smoke on cell proliferation, global histone marks, gene expression, and promoter-related chromatin structure.

Results

CSC and WPC decreased global H4K16ac and H4K20me3 histone marks and mediated distinct and overlapping cancer-associated transcriptome signatures and pathway modulations that were cell line dependent and stratified across lung cancer cells in a histology-specific manner. Epiregulin encoding a master regulator of EGFR signaling that is overexpressed in lung cancers was up-regulated, whereas FILIP1L and ABI3BP encoding mediators of senescence that are repressed in lung cancers were down-regulated by CSC and WPC. Induction of epiregulin and repression of FILIP1L and ABI3BP by these condensates coincided with unique epigenetic alterations within the respective promoters.

Conclusions

These findings support translational studies to ascertain if hookah-mediated epigenomic and transcriptomic alterations in cultured respiratory epithelia are detectable and clinically relevant in hookah smokers.

Deletion of Abi3 gene locus exacerbates neuropathological features of Alzheimer's disease in a mouse model of Aβ amyloidosis

Recently, large-scale human genetics studies identified a rare coding variant in the ABI3 gene that is associated with an increased risk of Alzheimer’s disease (AD). However, pathways by which ABI3 contributes to the pathogenesis of AD are unknown. To address this question, we determined whether loss of ABI3 function affects pathological features of AD in the 5XFAD mouse model. We demonstrate that the deletion of Abi3 locus significantly increases amyloid β (Aβ) accumulation and decreases microglia clustering around the plaques. Furthermore, long-term potentiation is impaired in 5XFAD;Abi3 knockout (“Abi3−/−”) mice. Moreover, we identified marked changes in the proportion of microglia subpopulations in Abi3−/− mice using a single-cell RNA sequencing approach. Mechanistic studies demonstrate that Abi3 knockdown in microglia impairs migration and phagocytosis. Together, our study provides the first in vivo functional evidence that loss of ABI3 function may increase the risk of developing AD by affecting Aβ accumulation and neuroinflammation.

The Depletion of ABI3BP by MicroRNA-183 Promotes the Development of Esophageal Carcinoma

Background

Esophageal cancer (EC), as a serious threat to human life and health, is one of the most common cancers around the world. Many studies have suggested that many microRNAs are involved in tumorigenesis and progression.

Methods

To search for a novel and promising predictive therapeutic target or biomarker to achieve the goal of the early diagnosis and treatment of EC, we used the EC cell lines Eca-109 and KYSE-150 and normal human esophageal epithelial cells (HEECs) to investigate the effect of ABI3BP on EC.

Results

We found that ABI family member 3 binding protein (ABI3BP) was downregulated in EC and suppressed the proliferation, activity, migration, and invasion of EC cells. ABI3BP was downregulated by miR-183, which plays the role of an oncogene.

Conclusion

ABI3BP and miR-183 can be considered potential biomarkers for the diagnosis of patients with EC and can be effective targets for antitumor therapy.

Long Non-Coding RNAs in Biliary Tract Cancer-An Up-to-Date Review

The term long non-coding RNA (lncRNA) describes non protein-coding transcripts with a length greater than 200 base pairs. The ongoing discovery, characterization and functional categorization of lncRNAs has led to a better understanding of the involvement of lncRNAs in diverse biological and pathological processes including cancer. Aberrant expression of specific lncRNA species was demonstrated in various cancer types and associated with unfavorable clinical characteristics. Recent studies suggest that lncRNAs are also involved in the development and progression of biliary tract cancer, a rare disease with high mortality and limited therapeutic options. In this review, we summarize current findings regarding the manifold roles of lncRNAs in biliary tract cancer and give an overview of the clinical and molecular consequences of aberrant lncRNA expression as well as of underlying regulatory functions of selected lncRNA species in the context of biliary tract cancer.

A comprehensive review of the roles of E2F1 in colon cancer

E2F transcription factor 1 (E2F1) is a member of the E2F family of transcription factors. E2F1 binds to DNA with dimerization partner (DP) proteins through an E2 recognition site. The dissociation of E2F1 from retinoblastoma (Rb) protein recovers its transcriptional activity, which drives the cell cycle from the G1 to S phase. E2F1 has been shown to be involved in cellular proliferation, differentiation, and apoptosis in colon cancer. It was recently found that E2F1 also participates in the metastasis and chemoresistance of colon cancer. There are abundant experimental data regarding the actions of E2F1, which can be grouped as either pro-tumorigenic or pro-apoptotic. Despite a growing interest and plentiful data, there is currently no review that focuses on the role of E2F1 in colon cancer. Research on E2F1 and colon cancer has been scattered over various genes and microRNAs (miRNAs) that affect E2F1 expression. Here, we provide the first review that aims to consider and dissect all of the elucidated complex behaviors of E2F1 in colon cancer. This review also provides an analysis and conclusion regarding the current understanding of E2F1 in colon cancer in order to facilitate the direction of future research.

"Amyloid-beta accumulation cycle" as a prevention and/or therapy target for Alzheimer's disease

The cell cycle and its regulators are validated targets for cancer drugs. Reagents that target cells in a specific cell cycle phase (e.g., antimitotics or DNA synthesis inhibitors/replication stress inducers) have demonstrated success as broad-spectrum anticancer drugs. Cyclin-dependent kinases (CDKs) are drivers of cell cycle transitions. A CDK inhibitor, flavopiridol/alvocidib, is an FDA-approved drug for acute myeloid leukemia. Alzheimer's disease (AD) is another serious issue in contemporary medicine. The cause of AD remains elusive, although a critical role of latent amyloid-beta accumulation has emerged. Existing AD drug research and development targets include amyloid, amyloid metabolism/catabolism, tau, inflammation, cholesterol, the cholinergic system, and other neurotransmitters. However, none have been validated as therapeutically effective targets. Recent reports from AD-omics and preclinical animal models provided data supporting the long-standing notion that cell cycle progression and/or mitosis may be a valid target for AD prevention and/or therapy. This review will summarize the recent developments in AD research: (a) Mitotic re-entry, leading to the "amyloid-beta accumulation cycle," may be a prerequisite for amyloid-beta accumulation and AD pathology development; (b) AD-associated pathogens can cause cell cycle errors; (c) thirteen among 37 human AD genetic risk genes may be functionally involved in the cell cycle and/or mitosis; and (d) preclinical AD mouse models treated with CDK inhibitor showed improvements in cognitive/behavioral symptoms. If the "amyloid-beta accumulation cycle is an AD drug target" concept is proven, repurposing of cancer drugs may emerge as a new, fast-track approach for AD management in the clinic setting.

Recurrent pregnancy loss is associated with a pro-senescent decidual response during the peri-implantation window

During the implantation window, the endometrium becomes poised to transition to a pregnant state, a process driven by differentiation of stromal cells into decidual cells (DC). Perturbations in this process, termed decidualization, leads to breakdown of the feto-maternal interface and miscarriage, but the underlying mechanisms are poorly understood. Here, we reconstructed the decidual pathway at single-cell level in vitro and demonstrate that stromal cells first mount an acute stress response before emerging as DC or senescent DC (snDC). In the absence of immune cell-mediated clearance of snDC, secondary senescence transforms DC into progesterone-resistant cells that abundantly express extracellular matrix remodelling factors. Additional single-cell analysis of midluteal endometrium identified DIO2 and SCARA5 as marker genes of a diverging decidual response in vivo. Finally, we report a conspicuous link between a pro-senescent decidual response in peri-implantation endometrium and recurrent pregnancy loss, suggesting that pre-pregnancy screening and intervention may reduce the burden of miscarriage.

DNA methylation in thyroid cancer

In recent years, cancer genomics has provided new insights into genetic alterations and signaling pathways involved in thyroid cancer. However, the picture of the molecular landscape is not yet complete. DNA methylation, the most widely studied epigenetic mechanism, is altered in thyroid cancer. Recent technological advances have allowed the identification of novel differentially methylated regions, methylation signatures and potential biomarkers. However, despite recent progress in cataloging methylation alterations in thyroid cancer, many questions remain unanswered. The aim of this review is to comprehensively examine the current knowledge on DNA methylation in thyroid cancer and discuss its potential clinical applications. After providing a general overview of DNA methylation and its dysregulation in cancer, we carefully describe the aberrant methylation changes in thyroid cancer and relate them to methylation patterns, global hypomethylation and gene-specific alterations. We hope this review helps to accelerate the use of the diagnostic, prognostic and therapeutic potential of DNA methylation for the benefit of thyroid cancer patients.

Long noncoding RNA MALAT1 potentiates growth and inhibits senescence by antagonizing ABI3BP in gallbladder cancer cells

Background

Gallbladder cancer (GBC) is the most malignant cancer occurring in the biliary tract cancer featured with undesirable prognosis, in which most patients die within a year of cholecystectomy. Long noncoding RNAs (lncRNAs) function as critical regulators of multiple stages of cancers. Herein, the mechanism of lncRNA metastasis associated lung adenocarcinoma transcript 1 (MALAT1) in GBC is investigated.

Methods

Microarray-based analysis initially provided data suggesting that the expression of MALAT1 was up-regulated while that of the ABI family member 3 binding protein (ABI3BP) was down-regulated in GBC tissues and cell lines. Kaplan-Meier method was then adopted to analyze the relationship between the MALAT1 expression and overall survival and disease-free survival of patients with GBC. A set of in vitro and in vivo experiments were conducted by transducing ABI3BP-vector or sh-MALAT1 into GBC cells.

Results

The results confirmed that the cancer prevention effects triggered by restored ABI3BP and depleted MALAT1 as evidenced by suppressed cell growth and enhanced cell senescence. MALAT1 was observed to down-regulate ABI3BP expression through recruitment of the enhancer of zeste homolog 2 (EZH2) to the ABI3BP promoter region while the silencing of MALAT1 or suppression of H3K27 methylation was observed to promote the expression of ABI3BP. Furthermore, GBC patients with high expression of MALAT1 indicated poor prognosis.

Conclusion

The current study clarifies that MALAT1 silencing and ABI3BP elevation impede the GBC development through the H3K27 methylation suppression induced by EZH2, highlighting a promising competitive paradigm for therapeutic approaches of GBC.

The Extracellular Matrix Protein ABI3BP in Cardiovascular Health and Disease

ABI3BP is a relatively newly identified protein whose general biological functions are not yet fully defined. It is implicated in promoting cellular senescence and cell-extracellular matrix interactions, both of which are of vital importance in the cardiovascular system. ABI3BP has been shown in multiple studies to be expressed in the heart and vasculature, and to have a role in normal cardiovascular function and disease. However, its precise role in the cardiovascular system is not known. Because ABI3BP is present in the cardiovascular system and is altered in cardiovascular disease states, further investigation into ABI3BP's biological and biochemical importance in cardiovascular health and disease is warranted.

Transcriptional regulation of the potential tumor suppressor ABI3 gene in thyroid carcinomas: interplay between methylation and NKX2-1 availability

We previously reported that ABI3 expression was decreased in thyroid cancer tissues and that ectopic expression of ABI3 in a follicular thyroid carcinoma cell line delayed cell cycle progression and inhibited cell proliferation, invasion, migration and tumor formation in athymic mice. These data indicated that ABI3 is a tumor suppressor gene; however the mechanism through which ABI3 is silenced in thyroid carcinomas is unknown. We here show that treatment of four follicular thyroid carcinoma cell lines with 5-aza-dC induced demethylation of a specific region of the ABI3 promoter and restored ABI3 expression. In contrast, 5-aza-dC treatment did not restore ABI3 expression in a non-thyroid cell line, suggesting a tissue-specific regulation. We additionally show that 8 CpG sites located within the ABI3 promoter are hypermethylated in most thyroid carcinoma samples and the degree of methylation correlated with ABI3 expression. Narrowing the region to specific CpG sites, the CpG_4-6 sites showed the largest difference between benign and malignant lesions. In silico analysis revealed that these CpG sites flank a canonical binding site for NKX2-1, a thyroid specific transcriptional factor. Analysis of thyroid samples shows a correlation between NKX2-1 and ABI3 expression. In vitro assays demonstrate that NKX2-1 was required for ABI3 expression. Luciferase assay further confirmed the promoter activity of this region, which was increased when the cells were co-transfected with NKX2-1. Our study shows that the transcriptional silencing of ABI3 in cancer cells occurs via methylation and uncovered a previously unrecognized role for NKX2-1 in the regulation of ABI3.

Microglia express ABI3 in the brains of Alzheimer's disease and Nasu-Hakola disease

Nasu-Hakola disease (NHD) is a rare autosomal recessive leukoencephalopathy caused by a loss-of-function mutation of either TYROBP (DAP12) or TREM2 expressed in microglia. A rare variant of the TREM2 gene encoding p.Arg47His causes a 3-fold increase in the risk for late-onset Alzheimer's disease (LOAD). A recent study demonstrated that a rare coding variant p.Ser209Phe in the ABI family member 3 (ABI3) gene, a regulator of actin cytoskeleton organization, confers risk of developing of LOAD, although the pattern of ABI3 expression in AD and NHD brains with relevance to microglial pathology remains to be characterized. We investigated the cell type-specific expression of ABI3 in the brains derived from four non-neurological controls (NC), ten AD and five NHD cases by immunohistochemistry. We identified an intense ABI3 immunoreactivity chiefly on a subset of microglia with ramified or amoeboid morphology located in the grey matter and the white matter of the frontal cortex and the hippocampus of NC, AD, and NHD cases. The immunolabeled area of ABI3-positive microglia was not significantly different among NC, AD, and NHD cases due to great variability from case to case. The clusters of ABI3-immunoreactive microglia were found exclusively in AD brains and they were associated with amyloid plaques. Although these observations do not actively support the view that ABI3-immunoreactive microglia play a central role in the development of leukoencephalopathy in NHD brains and the neurodegeneration in AD brains, the intense expression of ABI3 on microglia might regulate their migration under conditions of health and disease in the central nervous system (CNS).

Intrauterine growth restriction and placental gene expression in severe preeclampsia, comparing early-onset and late-onset forms

OBJECTIVE

To evaluate placental gene expression in severe early- or late-onset preeclampsia with intrauterine growth restriction compared to controls.

STUDY DESIGN

Chorionic villus sampling was conducted after cesarean section from the placentas of five women with early- or late-onset severe preeclampsia and five controls for each preeclampsia group. Microarray analysis was performed to identify gene expression differences between the groups.

RESULTS

Pathway analysis showed over-representation of gene ontology (GO) biological process terms related to inflammatory and immune response pathways, platelet development, vascular development, female pregnancy and reproduction in early-onset preeclampsia. Pathways related to immunity, complement and coagulation cascade were overrepresented in the hypergeometric test for the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. Ten genes (ABI3BP, C7, HLA-G, IL2RB, KRBOX1, LRRC15, METTL7B, MPP5, RFLNB and SLC20A) had a ≥±1 fold expression difference in severe early-onset preeclampsia group compared to early controls. There were 362 genes that had a ≥±1 fold expression difference in severe early-onset preeclampsia group compared to late-onset preeclampsia group including ABI3BP, C7, HLA-G and IL2RB.

CONCLUSION

There are significant differences in placental gene expression between severe early- and late-onset preeclampsia when both are associated with intrauterine growth restriction. ABI3BP, C7, HLA-G and IL2RB might contribute to the development of early form of severe preeclampsia.

Epigenetic Modifications: Novel Therapeutic Approach for Thyroid Cancer

The incidence of thyroid cancer is growing the fastest among all cancers in the United States, especially in women. The number of patients with thyroid neoplasm is part of an even larger number of patients who often need to undergo an operation to exclude a cancer diagnosis. While differentiated thyroid cancer (papillary thyroid cancer and follicular thyroid cancer) accounts for most cases of thyroid cancer and has a relatively good prognosis, effective treatments for patients with de-differentiated and anaplastic thyroid cancer are still gravely needed. Despite progress in the identification of genetic changes in thyroid cancer, the impact of aberrant epigenetic alterations on thyroid cancer remains to be fully elucidated. Understanding of the roles of epigenetic changes in thyroid cancer could open new opportunities for the identification of innovative molecular targets for novel treatment modalities, especially for anaplastic thyroid cancer for which treatment is very limited. This article briefly reviews the studies that exemplify the potential for and promise of using epigenetic regulators in the treatment of thyroid cancer.

ABI3, a component of the WAVE2 complex, is potentially regulated by PI3K/AKT pathway

We previously reported that ABI3 expression is lost in follicular thyroid carcinomas and its restoration significantly inhibited cell growth, invasiveness, migration, and reduced tumor growth in vivo. The mechanistic basis by which ABI3 exerts its tumor suppressive effects is not fully understood. In this study, we show that ABI3 is a phosphoprotein. Using proteomic array analysis, we showed that ABI3 modulated distinct cancer-related pathways in thyroid cancer cells. The KEA analysis found that PI3K substrates were enriched and forced expression of ABI3 markedly decreased the phosphorylation of AKT and the downstream-targeted protein pGSK3β. We next used immunoprecipitation combined with mass spectrometry to identify ABI3-interacting proteins that may be involved in modulating/integrating signaling pathways. We identified 37 ABI3 partners, including several components of the canonical WAVE regulatory complex (WRC) such as WAVE2/CYF1P1/NAP1, suggesting that ABI3 function might be regulated through WRC. Both, pharmacological inhibition of the PI3K/AKT pathway and mutation at residue S342 of ABI3, which is predicted to be phosphorylated by AKT, provided evidences that the non-phosphorylated form of ABI3 is preferentially present in the WRC protein complex. Collectively, our findings suggest that ABI3 might be a downstream mediator of the PI3K/AKT pathway that might disrupt WRC via ABI3 phosphorylation.

Evolution and heterogeneity of non-hereditary colorectal cancer revealed by single-cell exome sequencing

Recently single-cell whole-exome sequencing (scWES) has deeply expanded and sharpened our knowledge of cancer evolution and subclonality. Herein, with scWES and matched bulk whole-exome sequencing (bulk WES) on two colorectal cancer (CRC) patients with normal or adenomatous polyps, we found that both the adenoma and cancer were of monoclonal origin, and both shared partial mutations in the same signaling pathways, but each showed a specific spectrum of heterogeneous somatic mutations. In addition, the adenoma and cancer further developed intratumor heterogeneity with the accumulation of nonrandom somatic mutations specifically in GPCR, PI3K-Akt and FGFR signaling pathways. We identified novel driver mutations that developed during adenoma and cancer evolution, particularly in OR1B1 (GPCR signaling pathway) for adenoma evolution, and LAMA1 (PI3K-Akt signaling pathway) and ADCY3 (FGFR signaling pathway) for CRC evolution. In summary, we demonstrated that both colorectal adenoma and CRC are monoclonal in origin, and the CRCs further diversified into different subclones with heterogeneous mutation profiles accumulating in GPCR, PI3K-Akt and FGFR signaling pathways. ScWES provides evidence for the importance of mutations in certain pathways that would not be as apparent from bulk sequencing of tumors, and can potentially establish whether specific mutations are mutually exclusive or occur sequentially in the same subclone of cells.

PVALB diminishes [Ca2+] and alters mitochondrial features in follicular thyroid carcinoma cells through AKT/GSK3β pathway

We have identified previously a panel of markers (C1orf24, ITM1 and PVALB) that can help to discriminate benign from malignant thyroid lesions. C1orf24 and ITM1 are specifically helpful for detecting a wide range of thyroid carcinomas, and PVALB is particularly valuable for detecting the benign Hürthle cell adenoma. Although these markers may ultimately help patient care, the current understanding of their biological functions remains largely unknown. In this article, we investigated whether PVALB is critical for the acquisition of Hürthle cell features and explored the molecular mechanism underlying the phenotypic changes. Through ectopic expression of PVALB in thyroid carcinoma cell lines (FTC-133 and WRO), we demonstrated that PVALB sequesters free cytoplasmic Ca(2+), which ultimately lowers calcium levels and precludes endoplasmic reticulum (ER) Ca(2+) refilling. These results were accompanied by induced expression of PERK, an ER stress marker. Additionally, forced expression of PVALB reduces Ca(2+) inflow in the mitochondria, which can in turn cause changes in mitochondria morphology, increase mitochondria number and alter subcellular localization. These findings share striking similarity to those observed in Hürthle cell tumors. Moreover, PVALB inhibits cell growth and induces cell death, most likely through the AKT/GSK-3β. Finally, PVALB expression coincides with Ca(2+) deposits in HCA tissues. Our data support the hypothesis that the loss of PVALB plays a role in the pathogenesis of thyroid tumors.

DNMT1 is essential for mammary and cancer stem cell maintenance and tumorigenesis

Mammary stem/progenitor cells (MaSCs) maintain self-renewal of the mammary epithelium during puberty and pregnancy. DNA methylation provides a potential epigenetic mechanism for maintaining cellular memory during self-renewal. Although DNA methyltransferases (DNMTs) are dispensable for embryonic stem cell maintenance, their role in maintaining MaSCs and cancer stem cells (CSCs) in constantly replenishing mammary epithelium is unclear. Here we show that DNMT1 is indispensable for MaSC maintenance. Furthermore, we find that DNMT1 expression is elevated in mammary tumors, and mammary gland-specific DNMT1 deletion protects mice from mammary tumorigenesis by limiting the CSC pool. Through genome-scale methylation studies, we identify ISL1 as a direct DNMT1 target, hypermethylated and downregulated in mammary tumors and CSCs. DNMT inhibition or ISL1 expression in breast cancer cells limits CSC population. Altogether, our studies uncover an essential role for DNMT1 in MaSC and CSC maintenance and identify DNMT1-ISL1 axis as a potential therapeutic target for breast cancer treatment.

Transcriptomic profiling suggests a role for IGFBP5 in premature senescence of endothelial cells after chronic low dose rate irradiation

PURPOSE

Ionizing radiation has been recognized to increase the risk of cardiovascular diseases (CVD). However, there is no consensus concerning the dose-risk relationship for low radiation doses and a mechanistic understanding of low dose effects is needed.

MATERIAL AND METHODS

Previously, human umbilical vein endothelial cells (HUVEC) were exposed to chronic low dose rate radiation (1.4 and 4.1 mGy/h) during one, three and six weeks which resulted in premature senescence in cells exposed to 4.1 mGy/h. To gain more insight into the underlying signaling pathways, we analyzed gene expression changes in these cells using microarray technology. The obtained data were analyzed in a dual approach, combining single gene expression analysis and Gene Set Enrichment Analysis.

RESULTS

An early stress response was observed after one week of exposure to 4.1 mGy/h which was replaced by a more inflammation-related expression profile after three weeks and onwards. This early stress response may trigger the radiation-induced premature senescence previously observed in HUVEC irradiated with 4.1 mGy/h. A dedicated analysis pointed to the involvement of insulin-like growth factor binding protein 5 (IGFBP5) signaling in radiation-induced premature senescence.

CONCLUSION

Our findings motivate further research on the shape of the dose-response and the dose rate effect for radiation-induced vascular senescence.

STAT3 targets suggest mechanisms of aggressive tumorigenesis in diffuse large B-cell lymphoma

The signal transducer and activator of transcription 3 (STAT3) is a transcription factor that, when dysregulated, becomes a powerful oncogene found in many human cancers, including diffuse large B-cell lymphoma. Diffuse large B-cell lymphoma is the most common form of non-Hodgkin's lymphoma and has two major subtypes: germinal center B-cell-like and activated B-cell-like. Compared with the germinal center B-cell-like form, activated B-cell-like lymphomas respond much more poorly to current therapies and often exhibit overexpression or overactivation of STAT3. To investigate how STAT3 might contribute to this aggressive phenotype, we have integrated genome-wide studies of STAT3 DNA binding using chromatin immunoprecipitation-sequencing with whole-transcriptome profiling using RNA-sequencing. STAT3 binding sites are present near almost a third of all genes that differ in expression between the two subtypes, and examination of the affected genes identified previously undetected and clinically significant pathways downstream of STAT3 that drive oncogenesis. Novel treatments aimed at these pathways may increase the survivability of activated B-cell-like diffuse large B-cell lymphoma.

An integrative analysis of cellular contexts, miRNAs and mRNAs reveals network clusters associated with antiestrogen-resistant breast cancer cells

Background

A major goal of the field of systems biology is to translate genome-wide profiling data (e.g., mRNAs, miRNAs) into interpretable functional networks. However, employing a systems biology approach to better understand the complexities underlying drug resistance phenotypes in cancer continues to represent a significant challenge to the field. Previously, we derived two drug-resistant breast cancer sublines (tamoxifen- and fulvestrant-resistant cell lines) from the MCF7 breast cancer cell line and performed genome-wide mRNA and microRNA profiling to identify differential molecular pathways underlying acquired resistance to these important antiestrogens. In the current study, to further define molecular characteristics of acquired antiestrogen resistance we constructed an “integrative network”. We combined joint miRNA-mRNA expression profiles, cancer contexts, miRNA-target mRNA relationships, and miRNA upstream regulators. In particular, to reduce the probability of false positive connections in the network, experimentally validated, rather than prediction-oriented, databases were utilized to obtain connectivity. Also, to improve biological interpretation, cancer contexts were incorporated into the network connectivity.

Results

Based on the integrative network, we extracted “substructures” (network clusters) representing the drug resistant states (tamoxifen- or fulvestrant-resistance cells) compared to drug sensitive state (parental MCF7 cells). We identified un-described network clusters that contribute to antiestrogen resistance consisting of miR-146a, -27a, -145, -21, -155, -15a, -125b, and let-7s, in addition to the previously described miR-221/222.

Conclusions

By integrating miRNA-related network, gene/miRNA expression and text-mining, the current study provides a computational-based systems biology approach for further investigating the molecular mechanism underlying antiestrogen resistance in breast cancer cells. In addition, new miRNA clusters that contribute to antiestrogen resistance were identified, and they warrant further investigation.

The mitochondrial transporter SLC25A43 is frequently deleted and may influence cell proliferation in HER2-positive breast tumors

Background

Overexpression of the human epidermal growth factor receptor (HER) 2 is associated with poor prognosis and shortened survival in breast cancer patients. HER2 is a potent activator of several signaling pathways that support cell survival, proliferation and metabolism. In HER2-positive breast cancer there are most likely unexplored proteins that act directly or indirectly downstream of well established pathways and take part in tumor development and treatment response.

Methods

In order to identify novel copy number variations (CNVs) in HER2-positive breast cancer whole-genome single nucleotide polymorphism (SNP) arrays were used. A PCR-based loss of heterozygosis (LOH) assay was conducted to verify presence of deletion in HER2-positive breast cancer cases but also in HER2 negative breast cancers, cervical cancers and lung cancers. Screening for mutations was performed using single-strand conformation polymorphism (SSCP) followed by PCR sequencing. Protein expression was evaluated with immunohistochemistry (IHC).

Results

A common deletion at chromosome Xq24 was found in 80% of the cases. This locus harbors the gene solute carrier (SLC) family 25A member 43 (SLC25A43) encoding for a mitochondrial transport protein. The LOH assay revealed presence of SLC25A43 deletion in HER2-positive (48%), HER2-negative (9%), cervical (42%) and lung (67%) cancers. HER2-positive tumors with negative or low SLC25A43 protein expression had significantly lower S-phase fraction compared to tumors with medium or high expression (P = 0.024).

Conclusions

We have found deletion in the SLC25A43 gene to be a common event in HER2-positive breast cancer as well as in other cancers. In addition, the SLC25A43 protein expression was shown to be related to S-phase fraction in HER2-positive breast cancer. Our results indicate a possible role of SLC25A43 in HER2-positive breast cancer and support the hypothesis of altered mitochondrial function in cancer.