ELK3 promotes the migration and invasion of liver cancer stem cells by targeting HIF-1α

Distinct patterns of proteostasis network gene expression are associated with different prognoses in melanoma patients

The proteostasis network (PN) is a collection of protein folding and degradation pathways that spans cellular compartments and acts to preserve the integrity of the proteome. The differential expression of PN genes is a hallmark of many cancers, and the inhibition of protein quality control factors is an effective way to slow cancer cell growth. However, little is known about how the expression of PN genes differs between patients and how this impacts survival outcomes. To address this, we applied unbiased hierarchical clustering to gene expression data obtained from primary and metastatic cutaneous melanoma (CM) samples and found that two distinct groups of individuals emerge across each sample type. These patient groups are distinguished by the differential expression of genes encoding ATP-dependent and ATP-independent chaperones, and proteasomal subunits. Differences in PN gene expression were associated with increased levels of the transcription factors, MEF2A, SP4, ZFX, CREB1 and ATF2, as well as markedly different survival outcomes. However, surprisingly, similar PN alterations in primary and metastatic samples were associated with discordant survival outcomes in patients. Our findings reveal that the expression of PN genes demarcates CM patients and highlights several new proteostasis sub-networks that could be targeted for more effective suppression of CM within specific individuals.

HIF-1α signaling: Essential roles in tumorigenesis and implications in targeted therapies

The hypoxic microenvironment is an essential characteristic of most malignant tumors. Notably, hypoxia-inducible factor-1 alpha (HIF-1α) is a key regulatory factor of cellular adaptation to hypoxia, and many critical pathways are correlated with the biological activity of organisms via HIF-1α. In the intra-tumoral hypoxic environment, HIF-1α is highly expressed and contributes to the malignant progression of tumors, which in turn results in a poor prognosis in patients. Recently, it has been indicated that HIF-1α involves in various critical processes of life events and tumor development via regulating the expression of HIF-1α target genes, such as cell proliferation and apoptosis, angiogenesis, glucose metabolism, immune response, therapeutic resistance, etc. Apart from solid tumors, accumulating evidence has revealed that HIF-1α is also closely associated with the development and progression of hematological malignancies, such as leukemia, lymphoma, and multiple myeloma. Targeted inhibition of HIF-1α can facilitate an increased sensitivity of patients with malignancies to relevant therapeutic agents. In the review, we elaborated on the basic structure and biological functions of HIF-1α and summarized their current role in various malignancies. It is expected that they will have future potential for targeted therapy.

ETS transcription factor ELK3 in human cancers: An emerging therapeutic target

Cancer is a genetic and complex disorder, resulting from several events associated with onset, development, and metastasis. Tumor suppressors and oncogenes are among the main regulators of tumor progression, contributing to various cancer-related behaviors like cell proliferation, invasion, migration, epithelial-mesenchymal transition (EMT), cell cycle, and apoptosis. Transcription factors (TFs) could act as tumor suppressors or oncogenes in cancer progression. E-twenty-six/E26 (ETS) family of TFs have a winged helix-turn-helix (HLH) motif, which interacted with specific DNA regions with high levels of purines and GGA core. ETS proteins act as transcriptional repressors or activators to modulate the expression of target genes. ETS transcription factor ELK3 (ELK3), as a type of ETS protein, was shown to enhance in various cancers, suggesting that it may have an oncogenic role. These studies indicated that ELK3 promoted invasion, migration, cell cycle, proliferation, and EMT, and suppressed cell apoptosis. In addition, these studies demonstrated that ELK3 could be a promising diagnostic and prognostic biomarker in human cancer. Moreover, accumulating data proved that ELK3 could be a novel chemoresistance mediator in human cancer. Here, we aimed to explore the overall change of ELK3 and its underlying molecular mechanism in human cancers. Moreover, we aimed to investigate the potential role of ELK3 as a prognostic and diagnostic biomarker as well as its capability as a chemoresistance mediator in cancer.

Glioma angiogenesis is boosted by ELK3 activating the HIF-1[Formula: see text]/VEGF-A signaling axis

BACKGROUND

Clinical studies have shown that first-line use of anti-angiogenetic therapy can prolong progression-free survival but little progress has been made in extending the overall survival of the patients. We explored the role of ELK3 in glioma angiogenesis to improve and design more efficacious therapies.

METHODS

A tissue microarray and immunohistochemistry analysis were used to determine the expression of ELK3 protein in 400 glioma patients. Cell proliferation, metastasis, cell cycle, and apoptosis were monitored in U87 and U251 cells using CCK-8, EdU, transwell assays, and flow cytometry. A tube-formation assay, a rat aorta ring sprouting assay, and a matrigel plug assay were performed to examine the antiangiogenic activity of ELK3. An ELISA, Western blot, and correlation analysis of the CGGA dataset were used to detect the association between ELK3 and VEGF-A or ELK3 and HIF-1[Formula: see text]. Besides, orthotopic transplantation in nude mice and histopathological and immunological analysis of in vitro tumors were used to explore the effect of ELK3 on tumor progression and median survival.

RESULTS

ELK3 was upregulated in glioma tissues and associated with a poor prognosis. In vitro, ELK3 promoted cell proliferation and cell cycle progression, induced metastasis, and suppressed apoptosis. Then, silencing ELK3 inhibited VEGF-A expression and secretion by facilitating HIF-1[Formula: see text] degradation via ubiquitination. Finally, knockdown ELK3 inhibited tumor progression and angiogenesis in vitro and in vivo, as well as prolonged nude mice's median survival.

CONCLUSIONS

Our findings first evidenced that ELK3 is crucial for glioma because it promotes angiogenesis by activating the HIF-1[Formula: see text]/VEGF-A signaling axis. Therefore, we suggest that ELK3 is a prognostic marker with a great potential for glioma angiogenesis and ELK3-targeted therapeutic strategies might hold promise in improving the efficacy of anti-angiogenic therapies.

Research progress on antitumor activity of XRP44X and analogues as microtubule targeting agents

Cancer threatens human health and life. Therefore, it is particularly important to develop safe and effective antitumor drugs. Microtubules, the main component of cytoskeleton, play an important role in maintaining cell morphology, mitosis, and signal transduction, which are one of important targets of antitumor drug research and development. Colchicine binding site inhibitors have dual effects of inhibiting proliferation and destroying blood vessels. In recent years, a series of inhibitors targeting this target have been studied and some progress has been made. XRP44X has a novel structure and overcomes some disadvantages of traditional inhibitors. It is also a multifunctional molecule that regulates not only the function of tubulin but also a variety of biological pathways. Therefore, the structure, synthesis, structure-activity relationship, and biological activity of XRP44X analogues reported in recent years were summarized in this paper, to provide a useful reference for the rational design of efficient colchicine binding site inhibitors.

ELK3 Targeting AEG1 Promotes Migration and Invasion of Ovarian Cancer Cells under Hypoxia

Ovarian cancer (OC) is one of the most common tumors in female reproductive organs with a five-year survival rate of less than 45%. Metastasis is a crucial contributor to OC development. ETS transcription factor (ELK3), as a transcriptional factor, have been involved in multiple tumor development. However, its role in OC remains elusive. In this study, we observed high expression of ELK3 and AEG1 in human OC tissues. OVCAR-3 and SKOV3 cells were treated with hypoxia to mimic tumor microenvironment in vivo. We found that the expression of ELK3 was significantly increased in cells under hypoxia compared with normoxia. ELK3 knockdown inhibited cell migration and invasion abilities under hypoxia. Moreover, ELK3 knockdown decreased β-catenin expression and inhibited the activation of Wnt/β-catenin pathway in SKOV3 cells under hypoxia. Astrocyte-elevated gene-1 (AEG1) has been reported to promote OC progression. Our results showed that the mRNA level of AEG1 was decreased when ELK3 knockdown under hypoxia. Dural luciferase assay confirmed that ELK3 bound to gene AEG1 promoter (-2005-+15) and enhanced its transcriptional activity under hypoxia. Overexpression of AEG1 increased the migration and invasion abilities of SKOV3 cell with ELK3 knockdown. In the absence of ELK3, the activation of β-catenin was recovered by AEG1 overexpression. To sum up, we conclude that ELK3 promotes AEG1 expression by binding to its promoter. ELK3 could promote migration and invasion of OC cells by targeting AEG1, which provides a potential basis for therapeutic approaches to OC.

Deubiquitinase UCHL5 stabilizes ELK3 to potentiate cancer stemness and tumor progression in pancreatic adenocarcinoma (PAAD)

Aberrant ubiquitin-proteasome system (UPS) contributes to tumorigeneisis or drug resistance of Pancreatic Adenocarcinoma (PAAD). Previous studies have implicated the deubiquitinase UCHL5 was abnormally expressed in multiple malignancies. However, little was reported about the specific roles of UCHL5 in PAAD. We aimed to identify the biological roles of UCHL5 in PAAD and demonstrate its prognostic significance. Differential analysis revealed that UCHL5 expressed highly in tumors versus normal tissues, like TCGA-PAAD, GSE28735, GSE15471 and collected samples. Patients with high UCHL5 expressions had worse survival outcomes relative to those with low UCHL5 levels. Experimental assays showed that UCHL5 overexpression could significantly enhance cell proliferation, colony formation and self-renewal capacities. UCHL5 could also promote PAAD migration in vitro and in vivo. Mechanistically, UCHL5 could directly deubiquitinate and stabilize ELK3 proteins. UCHL5 relied on accumulated ELK3 proteins to drive cell growth, stem-like properties and migration abilities. In addition, enrichment analysis based on RNA-seq data implicated that ELK3 mainly correlated with Notch1 signaling and ELK3 could notably elevate ELK3 mRNA levels. UCHL5 could thus promote self-renewal abilities of PAAD and targeting ELK3 could inhibit the stemness features. In contrast, UCHL5 deficiency could suppress PAAD stemness features, and ectopic expression of ELK3 could rescue this effect. Last of all, we utilized the UCHL5 inhibitor, b-AP15, to treat PAAD cells and found that b-AP15 could inhibit the growth of PAAD cells in a dose-dependent manner. Collectively, our study uncovered the underlying mechanisms of UCHL5/ELK3/Notch1 axis in PAAD progression and stemness maintaince, shedding light on individualized treatment and risk stratification for PAAD patients.

Identifying modifications on DNA-bound histones with joint deep learning of multiple binding sites in DNA sequence

MOTIVATION

Histone modifications are epigenetic markers that impact gene expression by altering the chromatin structure or recruiting histone modifiers. Their accurate identification is key to unraveling the mechanisms by which they regulate gene expression. However, the solutions for this task can be improved by exploiting multiple relationships from dataset and exploring designs of learning models, for example jointly learning technology.

RESULTS

This article proposes a deep learning-based multi-objective computational approach, iHMnBS, to identify which of the seven typical histone modifications a DNA sequence may choose to bind, and which parts of the DNA sequence bind to them. iHMnBS employs a customized dataset that allows the marking of modifications contained in histones that may bind to any position in the DNA sequence. iHMnBS tries to mine the information implicit in this richer data by means of deep neural networks. In comprehensive comparisons, iHMnBS outperforms a baseline method, and the probability of binding to modified histones assigned to a representative nucleotide of a DNA sequence can serve as a reference for biological experiments. Since the interaction between transcription factors and histone modifications has an important role in gene expression, we extracted a number of sequence patterns that may bind to transcription factors, and explored their possible impact on disease.

AVAILABILITY AND IMPLEMENTATION

The source code is available at https://github.com/lennylv/iHMnBS.

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

Molecular and clinical features of a potential immunotherapy target ELK3 in glioma

Glioma represents the most prevalent malignant primary brain cancer, and its treatment remains a tremendous challenge. Novel and efficient molecular targets are therefore required for improving diagnosis, survival prediction, and treatment outcomes. Additionally, some studies have shown that immunity is highly associated with glioma progression. Our study aimed to investigate the clinicopathological features, prognostic significance, and immunotherapeutic targetability of ELK3, a member of the erythroblast transformation-specific transcription factor family, in glioma using bioinformatics analyses. ELK3 transcript levels in glioma tissues were evaluated using the Gene Expression Omnibus and The Cancer Genome Atlas databases. Clinical and transcriptomic data of The Cancer Genome Atlas glioma patients were analyzed to identify the molecular and clinical characterizations of ELK3. The prognostic significance of ELK3 was assessed using Cox regression and Kaplan-Meier analysis. The biological pathways related to ELK3 expression were identified by gene set enrichment analysis. The relationships between ELK3 and inflammatory responses, immune cell infiltration, and immune checkpoints were explored using canonical correlation analysis and gene set variation analysis. ELK3 was upregulated in gliomas, and its high expression was correlated with advanced clinicopathologic features and unfavorable prognosis. Gene set enrichment analysis revealed that several immune-related pathways were tightly linked to high ELK3 expression. gene set variation analysis and correlograms demonstrated that ELK3 was robustly associated with inflammatory and immune responses. Correlation analyses indicated that ELK3 was positively associated with infiltrating immune cells and synergistic with several immune checkpoints. ELK3 may serve as a novel marker of poor prognosis and a potential immunotherapeutic target in glioma.

ELK3 Controls Gastric Cancer Cell Migration and Invasion by Regulating ECM Remodeling-Related Genes

Current therapeutic strategies for gastric cancer, including surgery and chemotherapy improve patient survival; however, the survival rate of patients with metastatic gastric cancer is very low. The molecular mechanisms underlying the dissemination of gastric cancer cells to distant organs are currently unknown. Here, we demonstrate that the E26 transformation-specific (ETS) transcription factor ELK3 (ELK3) gene is required for the migration and invasion of gastric cancer cells. The ELK3 gene modulates the expression of extracellular matrix (ECM) remodeling-related genes, such as bone morphogenetic protein (BMP1), lysyl oxidase like 2 (LOXL2), Snail family transcriptional repressor 1 (SNAI1), serpin family F member 1 (SERPINF1), decorin (DCN), and nidogen 1 (NID1) to facilitate cancer cell dissemination. Our in silico analyses indicated that ELK3 expression was positively associated with these ECM remodeling-related genes in gastric cancer cells and patient samples. The high expressions of ELK3 and other ECM remodeling-related genes were also closely associated with a worse prognosis of patients with gastric cancer. Collectively, these findings suggest that ELK3 acts as an important regulator of gastric cancer cell dissemination by regulating ECM remodeling.

LncRNAs, the Molecules Involved in Communications With Colorectal Cancer Stem Cells

Colorectal cancer stem cells (CRCSCs) can actively self-renew, as well as having multidirectional differentiation and tumor regeneration abilities. Because the high functional activities of CRCSCs are associated with low cure rates in patients with colorectal cancer, efforts have sought to determine the function and regulatory mechanisms of CRCSCs. To date, however, the potential regulatory mechanisms of CRCSCs remain incompletely understood. Many non-coding genes are involved in tumor invasion and spread through their regulation of CRCSCs, with long non-coding RNAs (lncRNAs) being important non-coding RNAs. LncRNAs may be involved in the colorectal cancer development and drug resistance through their regulation of CRCSCs. This review systematically evaluates the latest research on the ability of lncRNAs to regulate CRCSC signaling pathways and the involvement of these lncRNAs in colorectal cancer promotion and suppression. The regulatory network of lncRNAs in the CRCSC signaling pathway has been determined. Further analysis of the potential clinical applications of lncRNAs as novel clinical diagnostic and prognostic biomarkers and therapeutic targets for colorectal cancer may provide new ideas and protocols for the prevention and treatment of colorectal cancer.

ELK3: A New Molecular Marker for the Diagnosis and Prognosis of Glioma

ETS transcription factor ELK3 (ELK3), a novel oncogene, affects pathological processes and progression of many cancers in human tissues. However, it remains unclear whether ELK3, as a key gene, affects the pathological process of gliomas and the prognosis of patients with gliomas. This study aimed to comprehensively and systematically reveal the correlation between ELK3 and the malignant progression of gliomas by analyzing clinical sample information stored in multiple databases. We revealed the putative mechanism of ELK3 involvement in malignant gliomas progression and identified a new and efficient biomarker for glioma diagnosis and targeted therapy. Based on the sample data from multiple databases and real-time quantitative polymerase chain reaction (RT-qPCR), the abnormally high expression of ELK3 in gliomas was confirmed. Kaplan-Meier and Cox regression analyses demonstrated that a high ELK3 expression was markedly associated with low patient survival and served as an independent biomarker of gliomas. Wilcox and Kruskal-Wallis tests revealed that expression of ELK3 was positively correlated with several clinical characteristics of patients with gliomas, such as age, WHO classification, and recurrence. Moreover, Cell Counting Kit‐8 (CCK-8), immunofluorescence, and wound healing assays confirmed that ELK3 overexpression markedly promoted the proliferation and migration of glioma cells. Finally, gene set enrichment analysis (GSEA) and western blotting confirmed that overexpression of ELK3 regulated the JAK–STAT signaling pathway and upregulate the expression of signal transducer and activator of transcription 3 (STAT3) and phosphorylated STAT3 (P-STAT3) to promote the malignant transition of gliomas. Therefore, ELK3 may serve as an efficient biomarker for the diagnosis and prognosis of gliomas and it can also be used as a therapeutic target to improve the poor prognosis of patients with gliomas.

Single-Cell RNA Sequencing Analysis of the Heterogeneity in Gene Regulatory Networks in Colorectal Cancer

Colorectal cancer (CRC) manifests as gastrointestinal tumors with high intratumoral heterogeneity. Recent studies have demonstrated that CRC may consist of tumor cells with different consensus molecular subtypes (CMS). The advancements in single-cell RNA sequencing have facilitated the development of gene regulatory networks to decode key regulators for specific cell types. Herein, we comprehensively analyzed the CMS of CRC patients by using single-cell RNA-sequencing data. CMS for all malignant cells were assigned using CMScaller. Gene set variation analysis showed pathway activity differences consistent with those reported in previous studies. Cell–cell communication analysis confirmed that CMS1 was more closely related to immune cells, and that monocytes and macrophages play dominant roles in the CRC tumor microenvironment. On the basis of the constructed gene regulation networks (GRNs) for each subtype, we identified that the critical transcription factor ERG is universally activated and upregulated in all CMS in comparison with normal cells, and that it performed diverse roles by regulating the expression of different downstream genes. In summary, molecular subtyping of single-cell RNA-sequencing data for colorectal cancer could elucidate the heterogeneity in gene regulatory networks and identify critical regulators of CRC.

[Expression characteristics and functional analysis of ELK3 in gastric cancer]

OBJECTIVE

To explore the expression characteristics of ELK3 and its role in the occurrence, progression and prognosis of gastric cancer.

METHODS

We analyzed the expression characteristics of ELK3 in gastric cancer based on E-MTAB-6693 dataset and explored the prognostic value of ELK3 using Kaplan-Meier survival analysis and univariate and multivariate Cox regression analysis. Chip-Atlas, ChipBase, Genes Transcription Regulation Database, and hTFtarget were used for predicting the target genes of ELK3 and constructing the transcription regulation network. Functional enrichment analysis of the target genes was performed using R software. The proportions of infiltrating immune cells in gastric cancer were analyzed using Cibersort tool, and the Pearson coefficients between ELK3 and these cells were calculated. The expression profile of ELK3 was verified based on Gene Expression Profiling Interactive Analysis and Human Protein Atlas databases. We also collected 5 pairs of gastric cancer and adjacent tissue samples and detected the expression of ELK3 at both the mRNA and protein levels using RT-PCR and Western blotting.

RESULTS

In public datasets and clinical samples, ELK3 was highly expressed in gastric cancer (P < 0.05), and its expression increased with the progression of M stage, AJCC stage, and perineural invasion (P < 0.05). ELK3 expression was correlated with N stage, AJCC stage, Lauren classification, differentiation, pathological classification, and microsatellite status of gastric cancer (P < 0.05). A high expression of ELK3 was associated with significantly reduced overall survival and disease-free survival of the patients, and served as an independent prognostic factor of gastric cancer (P < 0.05). Comprehensive analysis identified 176 potential target genes of ELK3, and enrichment analysis showed that ELK3 may regulate Rap1, AMPK, chemokines, VEGF, TNF, and tumor PD-L1/PD-1 signaling (PP < 0.05). The expression of ELK3 was negatively correlated with regulatory T cells, follicular helper T cells, and CD8+T cells in gastric cancer (P < 0.05).

CONCLUSION

ELK3 acts as an oncogene in gastric cancer, and its high expression may promote the occurrence, progression and immune escape of gastric cancer.

Methyltransferase-like protein 11A promotes migration of cervical cancer cells via up-regulating ELK3

Cervical cancer is one of the common malignancies in women, which is characterized with high invasion and metastatic tendency in its advanced stage. Increasing evidence indicates that methyltransferase-like (METTL) gene family is involved in the progression of various cancers. However, the functional role of methyltransferase-like gene family in cervical cancer remains unclear. In the present study, we found that METTL11A, a member of the methyltransferase-like gene family, was significantly over-expressed in cervical carcinoma by analyzing TCGA database. This finding was further validated in clinical tissue samples. Moreover, ectopic expression of METTL11A in cervical cancer cell lines promoted cell proliferation and migration both in vitro and in vivo. Differential gene expression analysis in the transcriptomic sequencing data indicated that ELK3 was down-regulated in METTL11A-silenced cervical cancer cells, which was further verified at both protein and mRNA levels. Functional experiments identified that METTL11A promoted migration of cervical cancer cells in an ELK3-dependent manner. This study will promote understanding the mechanism of cervical cancer progression and the functional role of methyltransferase-like gene families in cancers.

Prognostic signature composed of transcription factors accurately predicts the prognosis of gastric cancer patients

BACKGROUND

Transcription factors (TFs) are involved in important molecular biological processes of tumor cells and play an essential role in the occurrence and development of gastric cancer (GC).

METHODS

Combined The Cancer Genome Atlas Program and Genotype-Tissue Expression database to extract the expression of TFs in GC, analyzed the differences, and weighted gene co-expression network analysis to extract TFs related to GC. The cohort including the training and validation cohort. Univariate Cox, least absolute contraction and selection operator (LASSO) regression, and multivariate Cox analysis was used for screening hub TFs to construct the prognostic signature in the training cohort. The Kaplan-Meier (K-M) and the receiver operating characteristic curve (ROC) was drawn to evaluate the predictive ability of the prognostic signature. A nomogram combining clinical information and prognostic signatures of TFs was constructed and its prediction accuracy was evaluated through various methods. The target genes of the hub TFs was predicted and enrichment analysis was performed to understand its molecular biological mechanism. Clinical samples and public data of GC was collected to verify its expression and prognosis. 5-Ethynyl-2'-deoxyuridine and Acridine Orange/Ethidium Bromide staining, flow cytometry and Western-Blot detection were used to analyze the effects of hub-TF ELK3 on the proliferation and apoptosis of gastric cancer in vitro.

RESULTS

A total of 511 misaligned TFs were obtained and 200 GC-related TFs were exposed from them. After systematic analysis, a prognostic signature composed of 4 TFs (ZNF300, ELK3, SP6, MEF2B) were constructed. The KM and ROC curves demonstrated the good predictive ability in training, verification, and complete cohort. The areas under the ROC curve are respectively 0.737, 0.705, 0.700. The calibration chart verified that the predictive ability of the nomogram constructed by combining the prognostic signature of TFs and clinical information was accurate, with a C-index of 0.714. Enriching the target genes of hub TFs showed that it plays an vital role in tumor progression, and its expression and prognostic verification were consistent with the previous analysis. Among them, ELK3 was proved in vitro, and downregulation of its expression inhibited the proliferation of gastric cancer cells, induced proliferation, and exerted anti-tumor effects.

CONCLUSIONS

The 4-TFs prognostic signature accurately predicted the overall survival of GC, and ELK3 may be potential therapeutic targets for GC.

Deconvolution of sarcoma methylomes reveals varying degrees of immune cell infiltrates with association to genomic aberrations

BACKGROUND

Soft-tissue sarcomas (STS) are a heterogeneous group of mesenchymal tumors for which response to immunotherapies is not well established. Therefore, it is important to risk-stratify and identify STS patients who will most likely benefit from these treatments.

RESULTS

To reveal shared and distinct methylation signatures present in STS, we performed unsupervised deconvolution of DNA methylation data from the TCGA sarcoma and an independent validation cohort. We showed that leiomyosarcoma can be subclassified into three distinct methylation groups. More importantly, we identified a component associated with tumor-infiltrating leukocytes, which suggests varying degrees of immune cell infiltration in STS subtypes and an association with prognosis. We further investigated the genomic alterations that may influence tumor infiltration by leukocytes including RB1 loss in undifferentiated pleomorphic sarcomas and ELK3 amplification in dedifferentiated liposarcomas.

CONCLUSIONS

In summary, we have leveraged unsupervised methylation-based deconvolution to characterize the immune compartment and molecularly stratify subtypes in STS, which may benefit precision medicine in the future.

The role of CD133 in hepatocellular carcinoma

Cancer stem cells (CSCs) represent a small subpopulation of cells found within tumors that exhibit properties of self-renewal, like normal stem cells. CSCs have been defined as a crucial factor involved in driving cancer relapse, chemoresistance and metastasis. Prominin-1 (CD133) is one of the most well-characterized markers of CSCs in various tumor types, including hepatocellular carcinoma (HCC). CD133+ cells have been demonstrated to be involved in metastasis, tumorigenesis, tumor recurrence, and resistance to treatment in HCC. CD133-related clinical prognosis prediction, and targeted therapy have highlighted the clinical significance of CD133 in HCC. However, there remains controversy over the role of CD133 in experimental and clinical research involving HCC. In this article, we summarize the fundamental cell biology of CD133 in HCC cells and discuss the important characteristics of CD133+ in HCC cells. Furthermore, the prognostic value of CD133, and therapeutic strategies for its targeting in HCC, is also reviewed.

LncRNA KLK8 modulates stem cell characteristics in colon cancer

BACKGROUND

Colon cancer, one of the most common and aggressive human malignancies, is the third leading cause of cancer-related death worldwide. Despite advances in systemic therapy, the 5-year survival rate of colon cancer patients remains at 30 % due to recurrence and metastasis. The poor prognosis is related to the presence of cancer stem cells (CSCs), and long non-coding RNAs (lncRNAs) play a significant role in CSCs. Thus, understanding of the correlation between CSCs and lncRNA in colon cancer is of it is of great clinical significance.

METHOD

The expression of KLK8 expression in colon cancer tissues was determined by qRT-PCR. Colon cancer-derived CSCs could form sphere-like cell aggregates after 10 days of culturing in a serum-free medium. In addition, qRT-PCR and Western blotting were performed to assess the expression of CD44, Sox2, Oct4, and Nanog.

RESULTS

KLK8 was markedly upregulated in colon cancer tissues in comparison with normal tissues, and its expression was related to tumor size, TNM stage, and metastasis, and positively correlated with the expression of CSCs-related genes in colon cancer tissues.

CONCLUSIONS

Thus, KLK8 may serve as a potential prognostic and diagnostic biomarker in colon cancer patients.

Advances in Liver Cancer Stem Cell Isolation and their Characterization

Over the last decade research on cancer stem cells (CSC) significantly contributed to a better understanding of tumor biology. Given their similarity to normal stem cells, i.e. self-renewal and pluripotency the need arises to develop robust protocols for the isolation and characterization of CSCs. As with other malignancies, hepatic tumors are composed of a heterogeneous population of cells including liver cancer stem cells (LCSC). Yet, a precise understanding of why stem cells become cancerous is still lacking. There is unmet need to develop robust protocols for the successful isolation of LCSCs from human tissue resection material as to assist in the development of molecular targeted therapies. Here we review the research progress made in the isolation and characterization of LCSCs by considering a wide range of cell surface markers and sorting methods, as applied to side populations, microsphere cultures and the gradient centrifugation method. We emphasize the different fluorescence activated cell sorting methods and the possibility to enrich LCSCs by immunomagnetic beads. We review the specificity of functional assays by considering ABCG transporter and ALDH1 enzyme activities and evaluate the in vivo tumorigenicity of LCSCs in highly sensitive bioassays. Finally, we evaluate different LCSC markers in association with viral and non-viral liver disease and explore the potential of novel drug delivery systems targeting CD133, EpCAM, CD13 and CD90 for the development of molecular targeted therapies. Graphical Abstract.

LINC01106 post-transcriptionally regulates ELK3 and HOXD8 to promote bladder cancer progression

Bladder cancer (BCa) is a kind of common urogenital malignancy worldwide. Emerging evidence indicated that long noncoding RNAs (lncRNAs) play critical roles in the progression of BCa. In this study, we discovered a novel lncRNA LINC01116 whose expression increased with stages in BCa patients and closely related to the survival rate of BCa patients. However, the molecular mechanism dictating the role of LINC01116 in BCa has not been well elucidated so far. In our study, we detected that the expression of LINC01116 was boosted in BCa cells. Moreover, the results of a series of functional assays showed that LINC01116 knockdown suppressed the proliferation, migration, and invasion of BCa cells. Thereafter, GEPIA indicated the closest correlation of LINC01116 with two protein-coding genes, ELK3 and HOXD8. Interestingly, LINC01116 was mainly a cytoplasmic lncRNA in BCa cells, and it could modulate ELK3 and HOXD8 at post-transcriptional level. Mechanically, LINC01116 increased the expression of ELK3 by adsorbing miR-3612, and also stabilized HOXD8 mRNA by binding with DKC1. Rescue experiments further demonstrated that the restraining influence of LINC01116 knockdown on the progression of BCa, was partly rescued by ELK3 promotion, but absolutely reversed by the co-enhancement of ELK3 and HOXD8. More intriguingly, HOXD8 acted as a transcription factor to activate LINC01116 in BCa. In conclusion, HOXD8-enhanced LINC01116 contributes to the progression of BCa via targeting ELK3 and HOXD8, which might provide new targets for treating patients with BCa.

Role of hypoxia inducible factor-1 in cancer stem cells (Review)

Cancer stem cells (CSCs) have been found to play a decisive role in cancer recurrence, metastasis, and chemo‑, radio‑ and immuno‑resistance. Understanding the mechanism of CSC self‑renewal and proliferation may help overcome the limitations of clinical treatment. The microenvironment of tumor growth consists of a lack of oxygen, and hypoxia has been confirmed to induce cancer cell invasion, metastasis and epithelial‑mesenchymal transition, and is usually associated with poor prognosis and low survival rates. Hypoxia inducible factor‑1 (HIF‑1) can be stably expressed under hypoxia and act as an important molecule to regulate the development of CSCs, but the specific mechanism remains unclear. The present review attempted to explain the role of HIF‑1 in the generation and maintenance of CSCs from the perspective of epigenetics, metabolic reprogramming, tumor immunity, CSC markers, non‑coding RNA and signaling pathways associated with HIF‑1, in order to provide novel targets with HIF‑1 as the core for clinical treatment, and extend the life of patients.

Recent Advances in Liver Cancer Stem Cells: Non-coding RNAs, Oncogenes and Oncoproteins

Hepatocellular carcinoma (HCC) is one of the most prevalent malignancies worldwide, with high morbidity, relapse, metastasis and mortality rates. Although liver surgical resection, transplantation, chemotherapy, radiotherapy and some molecular targeted therapeutics may prolong the survival of HCC patients to a certain degree, the curative effect is still poor, primarily because of tumor recurrence and the drug resistance of HCC cells. Liver cancer stem cells (LCSCs), also known as liver tumor-initiating cells, represent one small subset of cancer cells that are responsible for disease recurrence, drug resistance and death. Therefore, understanding the regulatory mechanism of LCSCs in HCC is of vital importance. Thus, new studies that present gene regulation strategies to control LCSC differentiation and replication are under development. In this review, we provide an update on the latest advances in experimental studies on non-coding RNAs (ncRNAs), oncogenes and oncoproteins. All the articles addressed the crosstalk between different ncRNAs, oncogenes and oncoproteins, as well as their upstream and downstream products targeting LCSCs. In this review, we summarize three pathways, the Wnt/β-catenin signaling pathway, phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway, and interleukin 6/Janus kinase 2/signal transducer and activator of transcription 3 (IL6/JAK2/STAT3) signaling pathway, and their targeting gene, c-Myc. Furthermore, we conclude that octamer 4 (OCT4) and Nanog are two important functional genes that play a pivotal role in LCSC regulation and HCC prognosis.

Hypoxia induces an endometrial cancer stem-like cell phenotype via HIF-dependent demethylation of SOX2 mRNA

Endometrial cancer stem cells (ECSCs) are stem-like cells endowed with self-renewal and differentiation abilities, and these cells are essential for cancer progression in endometrial cancer (EC). As hallmarks of the tumour microenvironment (TME), hypoxia and hypoxia-inducing factors (HIFs) give rise to the dysregulation of tumour stemness genes, such as SOX2. Against this backdrop, we investigated the regulatory mechanisms regulated by HIFs and SOX2 in ECSCs during EC development. Here, ECSCs isolated from EC cell lines and tissues were found to express stemness genes (CD133 and aldehyde dehydrogenase, ALDH1) following the induction of their ECSC expansion. Notably, m⁶A methylation of RNA and HIF-1α/2α-dependent AlkB homologue 5 (ALKBH5) participate in the regulation of HIFs and SOX2 in EC, as confirmed by the observations that mRNA levels of m⁶A demethylases and ALKBH5 significantly increase under hypoxic conditions in ECSCs. Moreover, hypoxia and high ALKBH5 levels restore the stem-like state of differentiated ECSCs and increase the ECSC-like phenotype, whereas the knockdown of HIFs or ALKBH5 significantly reduces their tumour initiation capacity. In addition, our findings validate the role of ALKBH5 in promoting SOX2 transcription via mRNA demethylation, thereby maintaining the stem-like state and tumorigenicity potential of ECSCs. In conclusion, these observations demonstrate a critical role for m⁶A methylation-mediated regulation of the HIF-ALKBH5-SOX2 axis during ECSC expansion in hypoxic TMEs.

Strategy of differentiation therapy: effect of dual-frequency ultrasound on the induction of liver cancer stem-like cells on a HA-based multilayer film system

Cancer stem cells (CSCs) and normal stem cells share the ability to self-renew and drive tumor formation, recurrence, and distant metastasis and are resistant to chemotherapeutic drugs. One potential therapeutic approach for targeting CSCs is to induce CSCs to differentiate into normal cancer cells to eliminate self-renewal and enhance drug sensitivity. We developed a hyaluronic acid (HA)-based multilayer film system for selecting CSC-like hepatocellular carcinoma (HCC) cell colonies. Herein, we assess the differentiation therapy of HCC CSCs using dual-frequency low-intensity ultrasound (LIUS). HA-based multilayer films of poly (allylamine hydrochloride), (PAH/HA)6, were used to isolate CSC colonies. Colony formation, maintenance, and CSC marker expression were identified. The colony-formation rate was investigated, and putative CSC markers for CD44/CD133 expression after 7 days of culture were upregulated on (PAH/HA)6 multilayer films. Dual-frequency LIUS was used to induce CSC colony differentiation, and the phenotype variation, CSC marker expression, gene expression, drug-resistance ability, and invasion ability of CSC colonies with/without LIUS stimulation were compared. The numbers of colonies and CD44/CD133 double-positive cells and the expression levels of stem cell-related genes and proteins associated with stemness all decreased due to differentiation after LIUS exposure. Furthermore, a significant reduction in CSC drug resistance and invasion ability was observed. These results indicate that dual-frequency LIUS induces CSC differentiation and reduces drug resistance and invasion ability. Differentiation of CSCs provides an alternative therapeutic strategy to reverse CSC stemness and force their loss of self-renewal ability. CSC-targeted therapy holds great promise as an effective therapeutic approach for the treatment of human tumors.

Host Genetic Factors Associated with Vaginal Microbiome Composition in Kenyan Women

Bacterial vaginosis (BV) affects 20% of women worldwide and is associated with adverse reproductive health outcomes and increased risk for HIV. Typically, BV represents a shift in the vaginal microbiome from one that is dominated by Lactobacillus to one that is diverse. Persistent racial differences in BV and diverse vaginal microbiome composition overlap with racial disparities in risks for HIV and sexually transmitted infection, especially among women of African descent. Risk factors for BV and nonoptimal vaginal microbiome include sexual practices, yet racial differences persist when adjusted for behavioral factors, suggesting a host genetic component. Here, we perform a genome-wide association study on vaginal microbiome traits in Kenyan women. Linear regression and logistic regression were performed, adjusting for age and principal components of genetic ancestry, to evaluate the association between Lactobacillus crispatus, Lactobacillus iners, Gardnerella vaginalis, Shannon diversity index, and community state type (CST) with host genetic single nucleotide polymorphisms (SNPs). We identified novel genomic loci associated with the vaginal microbiome traits, though no SNP reached genome-wide significance. During pathway enrichment analysis, Toll-like receptors (TLRs), cytokine production, and other components of innate immune response were associated with L. crispatus, L. iners, and CST. Multiple previously reported genomic loci were replicated, including IL-8 (Shannon, CST), TIRAP (L. iners, Shannon), TLR2 (Shannon, CST), MBL2 (L. iners, G. vaginalis, CST), and MYD88 (L. iners, Shannon). These genetic associations suggest a role for the innate immune system and cell signaling in vaginal microbiome composition and susceptibility to nonoptimal vaginal microbiome.IMPORTANCE Globally, bacterial vaginosis (BV) is a common condition in women. BV is associated with poorer reproductive health outcomes and HIV risk. Typically, BV represents a shift in the vaginal microbiome from one that is dominated by Lactobacillus to one that is diverse. Despite many women having similar exposures, the prevalence of BV and nonoptimal vaginal microbiome is increased for women of African descent, suggesting a possible role for host genetics. We conducted a genome-wide association study of important vaginal microbiome traits in Kenyan women. We identified novel genetic loci and biological pathways related to mucosal immunity, cell signaling, and infection that were associated with vaginal microbiome traits; we replicated previously reported loci associated with mucosal immune response. These results provide insight into potential host genetic influences on vaginal microbiome composition and can guide larger longitudinal studies, with genetic and functional comparison across microbiome sites within individuals and across populations.

Single-cell transcriptomic analysis in a mouse model deciphers cell transition states in the multistep development of esophageal cancer

Esophageal squamous cell carcinoma (ESCC) is prevalent in some geographical regions of the world. ESCC development presents a multistep pathogenic process from inflammation to invasive cancer; however, what is critical in these processes and how they evolve is largely unknown, obstructing early diagnosis and effective treatment. Here, we create a mouse model mimicking human ESCC development and construct a single-cell ESCC developmental atlas. We identify a set of key transitional signatures associated with oncogenic evolution of epithelial cells and depict the landmark dynamic tumorigenic trajectories. An early downregulation of CD8⁺ response against the initial tissue damage accompanied by the transition of immune response from type 1 to type 3 results in accumulation and activation of macrophages and neutrophils, which may create a chronic inflammatory environment that promotes carcinogen-transformed epithelial cell survival and proliferation. These findings shed light on how ESCC is initiated and developed.

Immune-related genes in tumor-specific CD4+ and CD8+ T cells in colon cancer

Background

Immune escape is an immunological mechanism underlying tumorigenesis, and T cells play an important role in this process. In this study, immune-related genes were evaluated in tumor-infiltrating CD4⁺ and CD8⁺ T cells in colon cancer.

Methods

ESTIMATE was used to calculate stromal and immune scores for tumor datasets downloaded from The Cancer Genome Atlas–Colon Cancer (COAD). Differentially expressed genes (DEGs) between samples with high and low stromal and immune scores were screened, followed by a functional enrichment analysis of the overlapping DEGs. The DEGs related to CD4⁺ and the CD8⁺ T cells were then screened. Predicted miRNA–mRNA and lncRNA–miRNA pairs were used to construct a competing endogenous RNA (ceRNA) network. Furthermore, chemical–gene interactions were predicted for genes in the ceRNA network. Kaplan–Meier survival curves were also plotted.

Results

In total, 83 stromal-related DEGs (5 up-regulated and 78 down-regulated) and 1270 immune-related DEGs (807 up-regulated and 293 down-regulated genes) were detected. The 79 overlapping DEGs were enriched for 39 biological process terms. Furthermore, 79 CD4⁺ T cell-related genes and 8 CD8⁺ T cell-related genes, such as ELK3, were screened. Additionally, ADAD1 and DLG3, related to CD4⁺ T cells, were significantly associated with the prognosis of patients with colon cancer. The chr22-38_28785274–29,006,793.1–miR-106a-5p-DDHD1 and chr22-38_28785274–29,006,793.1–miR-4319-GRHL1 axes obtained from CD4⁺ and CD8⁺ T cell-related ceRNAs were identified as candidates for further studies.

Conclusion

ELK3 is a candidate immune-related gene in colon cancer. The chr22-38_28785274–29,006,793.1–miR-106a-5p-DDHD1 and chr22-38_28785274–29,006,793.1–miR-4319-GRHL1 axes may be related to CD4⁺ and CD8⁺ T cell infiltration in colon cancer.

Analysis of hiPSCs differentiation toward hepatocyte-like cells upon extended exposition to oncostatin

The capability to produce and maintain functional human adult hepatocytes remains one of the major challenges for the use of in-vitro models toward liver cell therapy and industrial drug-screening applications. Among the suggested strategies to solve this issue, the use of human-induced pluripotent stem cells (hiPSCs), differentiated toward hepatocyte-like cells (HLCs) is promising. In this work, we propose a 31-day long protocol, that includes a final 14-day long phase of oncostatin treatment, as opposed to a 7-day treatment which led to the formation of a hepatic tissue functional for CYP1A2, CYP2B6, CYP2C8, CYP2D6, and CYP3A4. The production of albumin, as well as bile acid metabolism and transport, were also detected. Transcriptome profile comparisons and liver transcription factors (TFs) motif dynamics revealed increased expression of typical hepatic markers such as HNF1A and of important metabolic markers like PPARA. The performed analysis has allowed for the extraction of potential targets and pathways which would allow enhanced hepatic maturation in-vitro. From this investigation, NRF1 and SP3 appeared as transcription factors of importance. Complex epithelial-mesenchymal transition (EMT) and mesenchymal-epithelial transition (MET) patterns were also observed during the differentiation process. Moreover, whole transcriptome analysis highlighted a response typical of the one observed in liver regeneration and hepatocyte proliferation. While a complete maturation of hepatocytes was yet to be obtained, the results presented in this work provide new insights into the process of liver development and highlight potential targets aimed to improve in-vitro liver regeneration.

XRP44X Enhances the Cytotoxic Activity of Natural Killer Cells by Activating the c-JUN N-Terminal Kinase Signaling Pathway

Natural killer (NK) cells are innate lymphocytes that play an essential role in preventing cancer development by performing immune surveillance to eradicate abnormal cells. Since ex vivo expanded NK cells have cytotoxic activity against various cancers, including breast cancers, their clinical potential as immune-oncogenic therapeutics has been widely investigated. Here, we report that the pyrazole chemical XRP44X, an inhibitor of Ras/ERK activation of ELK3, stimulates NK-92MI cells to enhance cytotoxic activity against breast cancer cells. Under XRP44X stimulation, NK cells did not show notable apoptosis or impaired cell cycle progression. We demonstrated that XRP44X enhanced interferon gamma expression in NK-92MI cells. We also elucidated that potentiation of the cytotoxic activity of NK-92MI cells by XRP44X is induced by activation of the c-JUN N-terminal kinase (JNK) signaling pathway. Our data provide insight into the evaluation of XRP44X as an immune stimulant and that XRP44X is a potential candidate compound for the therapeutic development of NK cells.

Functional Link between miR-200a and ELK3 Regulates the Metastatic Nature of Breast Cancer

Triple-negative breast cancer (TNBC) refers to breast cancer that does not have receptors for estrogen, progesterone, and HER2 protein. TNBC accounts for 10–20% of all cases of breast cancers and is characterized by its metastatic aggressiveness, poor prognosis, and limited treatment options. Here, we show that the metastatic nature of TNBC is critically regulated by a functional link between miR-200a and the transcription factor ELK3. We found that the expression levels of miR-200a and the ELK3 mRNA were negatively correlated in the luminal and TNBC subtypes of breast cancer cells. In vitro experiments revealed that miR-200a directly targets the 3’ untranslated region (UTR) of the ELK3 mRNA to destabilize the transcripts. Furthermore, ectopic expression of miR-200a impaired the migration and invasion of TNBC cells by reducing the expression level of the ELK3 mRNA. In in vivo studies, transfection of MDA-MB 231 cells (a claudin-low TNBC cell type) with exogenous miR-200a reduced their extravasation into the lung during 48 h after tail vein injection, and co-transfection of the cells with an expression plasmid harboring ELK3 that lacked an intact 3’UTR recovered their extravasation ability. Overall, our findings provide evidences that miR-200a and ELK3 is functionally linked to regulate invasive characteristics of breast cancers.

SMAD3 promotes ELK3 expression following transforming growth factor β-mediated stimulation of MDA-MB231 cells

Transforming growth factor-β (TGFβ) is a secreted cytokine whose aberrant spatiotemporal expression is related to cancer progression and metastasis. While TGFβ acts as a tumor suppressor in normal and premalignant stages, TGFβ functions as a tumor promoter during the malignant phases of tumor progression by prompting cancer cells to undergo epithelial-mesenchymal transition (EMT), which enhances tumor cell invasion and ultimately promotes metastasis to other organs. Extensive studies have been performed to uncover the molecular and cellular mechanisms underlying TGFβ inducing EMT in cancer cells. Here, we suggested that ELK3, which encodes a protein that orchestrates invasion and metastasis of triple negative breast cancer cells, is a downstream target of TGFβ-SMAD3 in MDA-MB231 cells. ELK3 expression was increased in a time-dependent manner upon TGFβ treatment. Chemical and molecular inhibition of the TGFβ receptor blocked the ability of TGFβ to induce ELK3 expression. Small interfering RNA-mediated suppression analysis revealed that SMAD3 induces TGFβ signaling to express ELK3. Moreover, the results of the luciferase reporter assay and chromatin immunoprecipitation analysis showed that SMAD3 directly binds to the SMAD-binding element on the promoter of ELK3 to activate gene expression following TGFβ stimulation. We concluded that ELK3 is a novel downstream target of TGFβ-SMAD3 signaling in aggressive breast cancer cells.

Silencing of ELK3 Induces S-M Phase Arrest and Apoptosis and Upregulates SERPINE1 Expression Reducing Migration in Prostate Cancer Cells

ELK3, an ETS domain-containing transcription factor, participates in various physiological and pathological processes including cell proliferation, migration, angiogenesis, and malignant progression. However, the role of ELK3 in prostate cancer cells and its mechanism are not fully understood. The contribution of ELK3 to prostate cancer progression was investigated in the present study. We showed that silencing of ELK3 by siRNA in prostate cancer cell DU145 induced S-M phase arrest, promoted apoptosis, inhibited cell proliferation and migration in vitro, and suppressed xenograft growth in mice in vivo. In accordance with its ability to arrest cells in S-M phase, the expression of cyclin A and cyclin B was downregulated. In addition, the expression of p53 was upregulated following ELK3 knockdown, while that of antiapoptotic Bcl-2 was decreased. The migration inhibition may partly due to upregulation of SERPINE1 (a serine protease inhibitor) followed ELK3 knockdown. Consistently, downregulation of SERPINE1 resulted in a modest elimination of migration inhibition resulted from ELK3 knockdown. Furthermore, we found that the AKT signaling was activated in ELK3 knockdown cells, and treatment these cells with AKT inhibitor attenuated SERPINE1 expression induced by ELK3 silencing, suggesting that activation of AKT pathway may be one of the reasons for upregulation of SERPINE1 after ELK3 knockdown. In conclusion, modulation of ELK3 expression may control the progression of prostate cancer partly by regulating cell growth, apoptosis, and migration.

Cordycepin suppresses the migration and invasion of human liver cancer cells by downregulating the expression of CXCR4

Liver cancer is a worldwide threat to human health. High expression levels of C-X-C chemokine receptor type 4 (CXCR4) have been reported to promote the migration and invasion capacities of liver cancer cells. Cordycepin, extracted from Cordyceps militaris, has anti-inflammatory, antioxidant and anticancerous properties. Therefore, in the present study, migration assays, western blotting, reverse transcription-quantitative PCR and immunofluorescence analyses were conducted to determine whether cordycepin was able to suppress the migration and invasion abilities of liver cancer cells by inhibiting CXCR4 expression. The results suggested that cordycepin notably inhibited migration and invasion, and decreased the expression of CXCR4 in a dose-dependent manner. Activation of phosphorylated (p-) NF-κB inhibitor α (IκBα) and p-P65, the principal components of the NF-κB signaling pathway, was also downregulated. In addition, cordycepin markedly suppressed the nuclear translocation of P65, but had no effect on the expression of total IκBα (t-IκBα) and total P65 (t-P65). JSH-23, an inhibitor of the NF-κB pathway, impaired the migration of liver cancer cells, and was found to act synergistically with cordycepin. Furthermore, cordycepin treatment reduced the chemotactic migration ability of liver cancer cells to stromal cell-derived factor 1 (SDF1), which was significantly enhanced following treatment with JSH-23. Collectively, the present results indicated that cordycepin inhibited the nuclear translocation of P65 by preventing p-IκBα activation; this resulted in the downregulation of CXCR4 expression, and subsequently, in the impaired migration and invasion abilities of liver cancer cells and attenuated reactivity to SDF1. The current study revealed a novel mechanism for the antimetastatic activity of cordycepin and its potential to exert positive synergistic effects with other compounds for the treatment of liver cancer.

Long Non-Coding RNA LINC00525 Promotes the Stemness and Chemoresistance of Colorectal Cancer by Targeting miR-507/ELK3 Axis

Background and Objectives

This study aims to explore the effects of a long non-coding RNA, LINC00525, on colorectal cancer (CRC) and its underlying molecular mechanisms.

Methods

The qPCR, MTT, colony formation, Western blotting, Luciferase reporter and biotin pull-down, shRNA knockdown and DNA fragmentation assays were performed in this study.

Results

High expressions of LINC00525 were associated with poor prognosis of CRC patients. LINC00525 knockdown decreased stemness properties and increased sensitivities to oxaliplatin. MiR-507 was a direct target of LINC00525 and overexpression of miR-507 significantly decreased abilities of tumorsphere formation and cell growth. Overexpression of miR-507 resulted in a decrease of expression of cancer stem cell markers and the increase of apoptosis rates. MiR-507 regulated the expression of ELK3. In addition, LINC00525 knockdown decreased the expression of ELK3. Restoration of ELK3 expression abrogated the effects of LINC00525 knockdown. LINC00525 could be served as prognostic marker of CRC.

Conclusions

LINC00525 enhanced stemness properties and increased sensitivities of CRC cells to oxaliplatin by targeting miR-507/ELK3 axis.

LRG1 Promotes Keratinocyte Migration and Wound Repair through Regulation of HIF-1α Stability

Re-epithelialization is a complex process during skin wound healing, and cell migration is an integral part of this phenomenon. Here we identified a role for LRG1 as a key regulator of epidermal keratinocyte migration where LRG1 acts via enhancement of HIF-1α stability. We showed that LRG1 is upregulated at murine skin wound edges and that addition of recombinant human LRG1 accelerates keratinocyte migration and skin wound healing. Furthermore, we identified transcription factor ELK3 as a downstream effector of LRG1. We confirmed that elevated ELK3 levels manipulated by LRG1 can promote cell migration through upregulation of HIF-1α stability. Because hyperglycemia complicatedly affects HIF-1α stability and activation, our findings provide insights into the molecular controls of wound-associated cell migration and identify potential therapeutic targets for the treatment of chronic diabetic wounds. In conclusion, we demonstrated that LRG1 promotes wound repair through keratinocyte migration and is important for normalization of an abnormal process of diabetic wound healing where HIF-1α stability is insufficient.

Identification of a Five-CpG Signature with Diagnostic Value in Thyroid Cancer

Thyroid cancer (TC) ranks as the most common endocrine malignancy, and its incidence and mortality rates continue to rise annually. Increasing evidence have shown that DNA methylation, a kind of stable epigenetic modification, is associated with carcinogenesis, suggesting its potential as biomarkers for the early detection of tumors. With the aim of exploring likely DNA methylation biomarkers for TC diagnosis, we conducted a synthetic analysis of DNA methylation profiles based on 789 samples from the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) databases. In the discovery phase, we identified five CpG probes (cg11228682, cg01291854, cg06778183, cg01668008, and cg01702055) on the condition of DNA methylation data from GSE86961 (n = 82) and constructed a five-CpG signature-based diagnostic model for TC. In addition, we validated the diagnostic score formula in two independent training cohorts, GSE97466 (n = 141) and TCGA (n = 566), as well as the previous developing cohort GSE86961. Receiver operating characteristic analysis revealed that the five-CpG signature had a good diagnostic performance to distinguish TC samples from benign samples. In conclusion, our findings suggest that the five-CpG signature could provide a novel biomarker with useful applications in TC diagnosis.

ETS transcription factors as emerging drug targets in cancer

The ETS family of proteins consists of 28 transcription factors, many of which have been implicated in development and progression of a variety of cancers. While one family member, ERG, has been rigorously studied in the context of prostate cancer where it plays a critical role, other ETS factors keep emerging as potential hallmark oncodrivers. In recent years, numerous studies have reported initial discoveries of small molecule inhibitors of ETS proteins and opened novel avenues for ETS-directed cancer therapies. This review summarizes the state of the art data on therapeutic targeting of ETS family members and highlights the corresponding drug discovery strategies.

Targeting liver cancer stem cells for the treatment of hepatocellular carcinoma

Liver cancer is one of the most common malignant tumors and prognosis remains poor. It has been increasingly recognized that liver cancer stem cells (LCSCs) are responsible for the carcinogenesis, recurrence, metastasis and chemoresistance of hepatocellular carcinoma (HCC). Targeting LCSCs is promising to be a new direction for the treatment of HCC. Herein, we summarize the potentially therapeutic targets in LCSCs at the level of genes, molecules and cells, such as knockout of oncogenes or oncoproteins, restoring the silent tumor suppressor genes, inhibition of the transcription factors and regulation of noncoding RNAs (including microRNAs and long noncoding RNAs) in LCSCs at the genetic level; inhibition of markers and blockade of the key signaling pathways of LCSCs at the molecular level; and inhibiting autophagy and application of oncolytic adenoviruses in LCSCs at the cellular level. Moreover, we analyze the potential targets in LCSCs to eliminate chemoresistance of HCC. Thereinto, the suppression of autophagy and Nanog by chloroquine and shRNA respectively may be the most promising targeting approaches. These targets may provide novel therapeutic strategies for the treatment of HCC by targeting LCSCs.

HIF-1α promotes the migration and invasion of hepatocellular carcinoma cells via the IL-8-NF-κB axis

Background

Hypoxia plays a critical role in many cancers. Hypoxia inducible factor-1α (HIF-1α) is an important mediator of the hypoxia response. It regulates the expression of various chemokines involved in tumor growth, angiogenesis and metastasis but the associated pathway needs further investigation.

Methods

The expression level of HIF-1α was determined in hepatocellular carcinoma (HCC) cells. The correlation of interleukin-8 (IL-8) and HIF-1α was assessed by knocking down HIF-1α. These cells were also used to assess its influence on HCC cell migration and invasion was checked. Pyrrolidinedithiocarbamate (PDTC), an inhibitor of NF-κB, was used to confirm the associated signaling pathway.

Results

HIF-1α was significantly expressed in HCC cells and found to promote HCC cell migration and invasion in an IL-8-dependent manner. NF-κB was confirmed to be involved in the process.

Conclusions

HIF-1α promotes HCC cell migration and invasion by modulating IL-8 via the NF-κB pathway.

Hepatitis B virus upregulates GP73 expression by activating the HIF-2α signaling pathway

Golgi Protein 73 (GP73) is a newly identified diagnostic and prognostic marker for liver cancer. GP73 is highly expressed in liver cancer tissues, however, the mechanism of its overexpression in tumors remains unknown. In the present study, the effect of hepatitis B virus (HBV) on GP73 expression was investigated in HepG2 cells, which are negative for HBV, and in HepG2.2.12 cells, which are integrated with HBV, using reverse transcription-quantitative polymerase chain reaction and western blot analysis. In addition, the cells were transfected with plasmid constructs overexpressing hepatitis B virus protein X (HBx), hypoxia-inducible factor (HIF)-1α, or HIF-2α in order to examine their roles in GP73 expression. The results demonstrated that HBV upregulated the expression of GP73 and HIF-2α in liver cancer cells. HIF-2α induced the expression of GP73 in HepG2 cells and was positively correlated with GP73 expression in liver cancer tissues. By contrast, HBx and HIF-1α did not induce GP73 expression in liver cancer cells. In summary, HBV may upregulate the expression of GP73 by activating the HIF-2α signaling pathway. The present results may illuminate the mechanism by which GP73 is overexpressed in liver cancer tissues.

Roles of Wnt Target Genes in the Journey of Cancer Stem Cells

The importance of Wnt/β-catenin signaling in cancer stem cells (CSCs) has been acknowledged; however, the mechanism through which it regulates the biological function of CSCs and promotes cancer progression remains elusive. Hence, to understand the intricate mechanism by which Wnt controls stemness, the specific downstream target genes of Wnt were established by analyzing the genetic signatures of multiple types of metastatic cancers based on gene set enrichment. By focusing on the molecular function of Wnt target genes, the biological roles of Wnt were interpreted in terms of CSC dynamics from initiation to metastasis. Wnt signaling participates in cancer initiation by generating CSCs from normal stem cells or non-CSCs and augmenting persistent growth at the primary region, which is resistant to anti-cancer therapy. Moreover, it assists CSCs in invading nearby tissues and in entering the blood stream, during which the negative feedback of the Wnt signaling pathway maintains CSCs in a dormant state that is suitable for survival. When CSCs arrive at distant organs, another burst of Wnt signaling induces CSCs to succeed in re-initiation and colonization. This comprehensive understanding of Wnt target genes provides a plausible explanation for how Wnt allows CSCs variation during cancer progression.

Tg737 acts as a key driver of invasion and migration in liver cancer stem cells and correlates with poor prognosis in patients with hepatocellular carcinoma

We previously demonstrated that the Tg737 gene plays a critical role in the carcinogenesis of hepatocellular carcinoma (HCC). However, few systematic investigations have focused on the biological function of Tg737 in the invasion and migration of liver cancer stem cells (LCSCs) and on its clinical significance. In this study, Tg737 overexpression was achieved via gene transfection in MHCC97-H side population (SP) cells, which are considered a model for LCSCs in scientific studies. Tg737 overexpression significantly inhibited the invasion and migration of SP cells in an extracellular signal-regulated kinase1/2 (ERK1/2)/matrix metalloproteinase-2 (MMP-2)-dependent manner. Furthermore, Tg737 expression was frequently decreased in HCC tissues relative to that in adjacent noncancerous liver tissues. This decreased expression was significantly associated with tumor differentiation, the American Joint Committee on Cancer (AJCC) stage, metastasis, tumor size, vascular invasion, alpha-fetoprotein (AFP) levels, and tumor number. Moreover, multivariate Cox regression analyses demonstrated that Tg737 expression was an independent factor for predicting the overall survival of HCC patients. Notably, Kaplan-Meier analysis further showed that overall survival was significantly worse among patients with low Tg737 expression. Collectively, our findings demonstrated that Tg737 is a poor prognostic marker in patients with HCC, which may be due to its ability to promote LCSCs invasion and migration. These results provide a basis for investigating of Tg737 as a novel prognostic biomarker and therapeutic target.