Protein tyrosine phosphatase receptor S acts as a metastatic suppressor in hepatocellular carcinoma by control of epithermal growth factor receptor-induced epithelial-mesenchymal transition

Insights into Sorafenib resistance in hepatocellular carcinoma: Mechanisms and therapeutic aspects

The most prevalent primary hepatic cancer, hepatocellular carcinoma (HCC), has a bad prognosis. HCC prevalence and related deaths have increased in recent decades. Food and Drug Administration (FDA) has licensed Sorafenib as a first-line treatment for individuals with advanced HCC. Despite this, some clinical studies indicate that a significant percentage of liver cancer patients exhibit insensitivity to sorafenib. Furthermore, the overall effectiveness of sorafenib is far from adequate, and the number of patients who benefit from therapy is low. In recent years, many researchers have focused on the mechanisms underlying sorafenib resistance. Acquired resistance to sorafenib in HCC cells has been reported to be facilitated by dysregulation of signal transducer and activator of transcription 3 (STAT3) activation, angiogenesis, autophagy, hypoxia-induced pathways, epithelial-mesenchymal transition (EMT), cancer stem cells (CSCs), ferroptosis, and non-coding RNAs (ncRNAs). Recent clinical trials, including comparisons of sorafenib with immune checkpoint inhibitors like tislelizumab, have shown promise in improving patient outcomes. Additionally, combination therapies targeting complementary pathways are under investigation to overcome resistance and enhance treatment efficacy. The limitation of Sorafenib's effectiveness has been partially but not completely clarified. Furthermore, while certain regimens have demonstrated positive results, more clinical trials are required to confirm them. Future research should focus on identifying predictive biomarkers for therapy response, targeting the tumor microenvironment, and exploring novel therapeutic agents and personalized medicine strategies. A deeper understanding of these mechanisms will be essential for developing more effective therapeutic approaches and improving the prognosis of patients with advanced HCC. This article discusses strategies that may be employed to enhance the success of treatment and summarizes new research on the possible pathways that lead to sorafenib resistance.

Mass Spectrometry-Based Proteomics Analysis Unveils PTPRS Inhibits Proliferation and Inflammatory Response of Keratinocytes in Psoriasis

In this study, we used data-independent acquisition-mass spectrometry (DIA-MS) to analyze the serum proteome in psoriasis vulgaris (PsO). The serum proteomes of seven healthy controls and eight patients with PsO were analyzed using DIA-MS. Weighted gene co-expression network analysis was used to identify differentially expressed proteins (DEPs) that were closely related to PsO. Hub proteins of PsO were also identified. The Proteomics Drug Atlas 2023 was used to predict candidate hub protein drugs. To confirm the expression of the candidate factor, protein tyrosine phosphatase receptor S (PTPRS), in psoriatic lesions and the psoriatic keratinocyte model, immunohistochemical staining, quantitative real-time polymerase chain reaction, and western blotting were performed. A total of 129 DEPs were found to be closely related to PsO. The hub proteins for PsO were PVRL1, FGFR1, PTPRS, CDH2, CDH1, MCAM, and THY1. Five candidate hub protein drugs were identified: encorafenib, leupeptin, fedratinib, UNC 0631, and SCH 530348. PTPRS was identified as a common pharmacological target for these five drugs. PTPRS knockdown in keratinocytes promoted the proliferation and expression of IL-1α, IL-1β, IL-23A, TNF-α, MMP9, CXCL8, and S100A9. PTPRS expression was decreased in PsO, and PTPRS negatively regulated PsO. PTPRS may be involved in PsO pathogenesis through the inhibition of keratinocyte proliferation and inflammatory responses and is a potential treatment target for PsO.

Integrative Omics Uncovers Low Tumorous Magnesium Content as A Driver Factor of Colorectal Cancer

Magnesium (Mg) deficiency is associated with increased risk and malignancy in colorectal cancer (CRC), yet the underlying mechanisms remain elusive. Here, we used genomic, proteomic, and phosphoproteomic data to elucidate the impact of Mg deficiency on CRC. Genomic analysis identified 160 genes with higher mutation frequencies in Low-Mg tumors, including key driver genes such as KMT2C and ERBB3. Unexpectedly, initiation driver genes of CRC, such as TP53 and APC, displayed higher mutation frequencies in High-Mg tumors. Additionally, proteomic and phosphoproteomic data indicated that low Mg content in tumors may activate epithelial-mesenchymal transition (EMT) by modulating inflammation or remodeling the phosphoproteome of cancer cells. Notably, we observed a negative correlation between the phosphorylation of DBN1 at S142 (DBN1S142p) and Mg content. A mutation in S142 to D (DBN1S142D) mimicking DBN1S142p up-regulated MMP2 and enhanced cell migration, while treatment with MgCl2 reduced DBN1S142p, thereby reversing this phenotype. Mechanistically, Mg2+ attenuated the DBN1-ACTN4 interaction by decreasing DBN1S142p, which in turn enhanced the binding of ACTN4 to F-actin and promoted F-actin polymerization, ultimately reducing MMP2 expression. These findings shed new light on the crucial role of Mg deficiency in CRC progression and suggest that Mg supplementation may be a promising preventive and therapeutic strategy for CRC.

Chronic TNF exposure induces glucocorticoid-like immunosuppression in the alveolar macrophages of aged mice that enhances their susceptibility to pneumonia

Chronic low-grade inflammation, particularly elevated tumor necrosis factor (TNF) levels, occurs due to advanced age and is associated with greater susceptibility to infection. One reason for this is age-dependent macrophage dysfunction (ADMD). Herein, we use the adoptive transfer of alveolar macrophages (AM) from aged mice into the airway of young mice to show that inherent age-related defects in AM were sufficient to increase the susceptibility to Streptococcus pneumoniae, a Gram-positive bacterium and the leading cause of community-acquired pneumonia. MAPK phosphorylation arrays using AM lysates from young and aged wild-type (WT) and TNF knockout (KO) mice revealed multilevel TNF-mediated suppression of kinase activity in aged mice. RNAseq analyses of AM validated the suppression of MAPK signaling as a consequence of TNF during aging. Two regulatory phosphatases that suppress MAPK signaling, Dusp1 and Ptprs, were confirmed to be upregulated with age and as a result of TNF exposure both ex vivo and in vitro. Dusp1 is known to be responsible for glucocorticoid-mediated immune suppression, and dexamethasone treatment increased Dusp1 and Ptprs expression in cells and recapitulated the ADMD phenotype. In young mice, treatment with dexamethasone increased the levels of Dusp1 and Ptprs and their susceptibility to infection. TNF-neutralizing antibody reduced Dusp1 and Ptprs levels in AM from aged mice and reduced pneumonia severity following bacterial challenge. We conclude that chronic exposure to TNF increases the expression of the glucocorticoid-associated MAPK signaling suppressors, Dusp1 and Ptprs, which inhibits AM activation and increases susceptibility to bacterial pneumonia in older adults.

Inhibition of PTPRE suppresses tumor progression and improves sorafenib response in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) has a poor prognosis, and the efficacy of current therapeutic strategies is extremely limited in advanced diseases. Our previous study reported that protein tyrosine phosphatase receptor epsilon (PTPRE) is a promoting factor in HCC progression. In this study, our objective was to evaluate the treatment effect of PTPRE inhibitors in different HCC preclinical models. Our results indicated that the PTPRE inhibitory compound 63 (Cpd-63) inhibited tumor cell proliferation, migration, and HCC organoid growth. Mechanism research revealed that Cpd-63 could inhibit the expression of MYC and MYC targets by inhibiting the activation of SRC. Additionally, we found that Cpd-63 could improve the response of sorafenib in HCC cells. In conclusion, we demonstrated that the PTPRE inhibitors represented a potential therapeutic agent for HCC management.

MultiGML: Multimodal graph machine learning for prediction of adverse drug events

Adverse drug events constitute a major challenge for the success of clinical trials. Several computational strategies have been suggested to estimate the risk of adverse drug events in preclinical drug development. While these approaches have demonstrated high utility in practice, they are at the same time limited to specific information sources. Thus, many current computational approaches neglect a wealth of information which results from the integration of different data sources, such as biological protein function, gene expression, chemical compound structure, cell-based imaging and others. In this work we propose an integrative and explainable multi-modal Graph Machine Learning approach (MultiGML), which fuses knowledge graphs with multiple further data modalities to predict drug related adverse events and general drug target-phenotype associations. MultiGML demonstrates excellent prediction performance compared to alternative algorithms, including various traditional knowledge graph embedding techniques. MultiGML distinguishes itself from alternative techniques by providing in-depth explanations of model predictions, which point towards biological mechanisms associated with predictions of an adverse drug event. Hence, MultiGML could be a versatile tool to support decision making in preclinical drug development.

Quantitative Evaluation of Stem-like Markers of Human Glioblastoma Using Single-Cell RNA Sequencing Datasets

Targeting glioblastoma (GBM) stem-like cells (GSCs) is a common interest in both the laboratory investigation and clinical treatment of GBM. Most of the currently applied GBM stem-like markers lack validation and comparison with common standards regarding their efficiency and feasibility in various targeting methods. Using single-cell RNA sequencing datasets from 37 GBM patients, we obtained a large pool of 2173 GBM stem-like marker candidates. To evaluate and select these candidates quantitatively, we characterized the efficiency of the candidate markers in targeting the GBM stem-like cells by their frequencies and significance of being the stem-like cluster markers. This was followed by further selection based on either their differential expression in GBM stem-like cells compared with normal brain cells or their relative expression level compared with other expressed genes. The cellular location of the translated protein was also considered. Different combinations of selection criteria highlight different markers for different application scenarios. By comparing the commonly used GSCs marker CD133 (PROM1) with markers selected by our method regarding their universality, significance, and abundance, we revealed the limitations of CD133 as a GBM stem-like marker. Overall, we propose BCAN, PTPRZ1, SOX4, etc. for laboratory-based assays with samples free of normal cells. For in vivo targeting applications that require high efficiency in targeting the stem-like subtype, the ability to distinguish GSCs from normal brain cells, and a high expression level, we recommend the intracellular marker TUBB3 and the surface markers PTPRS and GPR56.

Roles of protein tyrosine phosphatases in hepatocellular carcinoma progression (Review)

Hepatocellular carcinoma (HCC) represents almost 80% of all liver cancers, is the sixth most common cancer and is the second‑highest cause of cancer‑related deaths worldwide. Protein tyrosine phosphatases (PTPs), which are encoded by the largest family of phosphatase genes, play critical roles in cellular responses and are implicated in various signaling pathways. Moreover, PTPs are dysregulated and involved in various cellular processes in numerous cancers, including HCC. Kinases and phosphatases are coordinators that modulate cell activities and regulate signaling responses. There are multiple interacting signaling networks, and coordination of these signaling networks in response to a stimulus determines the physiological outcome. Numerous issues, such as drug resistance and inflammatory reactions in the tumor microenvironment, are implicated in cancer progression, and the role of PTPs in these processes has not been well elucidated. Therefore, the present review focused on discussing the relationship of PTPs with inflammatory cytokines and chemotherapy/targeted drug resistance, providing detailed information on how PTPs can modulate inflammatory reactions and drug resistance to influence progression in HCC.

High expression of protein tyrosine phosphatase receptor S (PTPRS) is an independent prognostic marker for cholangiocarcinoma

Cholangiocarcinoma (CCA) is an aggressive tumor of the bile duct with a high rate of mortality. Lymph node metastasis is an important factor facilitating the progression of CCA. A reliable biomarker for diagnosis, progression status, or prognosis of CCA is still lacking. To identify a novel and reliable biomarker for diagnosis/prognosis of CCA, liquid chromatography-mass spectrometry and tandem mass spectrometry (LC-MS/MS) in combination with bioinformatics analysis were applied for the representative serum samples of patients with CCA. The proteome results showed that protein tyrosine phosphatase receptor S (PTPRS) had the highest potential candidate. Then, a dot blot assay was used to measure the level of serum PTPRS in patients with CCA (n = 80), benign biliary disease patients (BBD; n = 39), and healthy controls (HC; n = 55). PTPRS level of CCA sera (14.38 ± 9.42 ng/ml) was significantly higher than that of BBD (10.7 ± 5.05 ng/ml) or HC (6 ± 3.73 ng/ml) (P < 0.0001). PTPRS was associated with serum albumin (P = 0.028), lymph node metastasis (P = 0.038), and the survival time of patients (P = 0.011). Using a log-rank test, higher serum PTPRS level was significantly (P = 0.031) correlated with a longer overall survival time of patients with CCA, and PTPRS was an independent prognostic marker for CCA superior to carbohydrate antigen 19-9 (CA19-9), carcinoembryonic antigen (CEA) or alkaline phosphatase (ALP). High expression of PTPRS could be a good independent prognostic marker for CCA.

Protein disulfide isomerase A1‑associated pathways in the development of stratified breast cancer therapies

The oxidoreductase protein disulfide isomerase A1 (PDIA1) functions as a cofactor for many transcription factors including estrogen receptor α (ERα), nuclear factor (NF)-κB, nuclear factor erythroid 2-like 2 (NRF2) and regulates the protein stability of the tumor suppressor p53. Taking this into account we hypothesized that PDIA1, by differentially modulating the gene expression of a diverse subset of genes in the ERα-positive vs. the ERα-negative breast cancer cells, might modify dissimilar pathways in the two types of breast cancer. This hypothesis was investigated using RNA-seq data from PDIA1-silenced MCF-7 (ERα-positive) and MDA-MB-231 (ERα-negative) breast cancer cells treated with either interferon γ (IFN-γ) or etoposide (ETO), and the obtained data were further analyzed using a variety of bioinformatic tools alongside clinical relevance assessment via Kaplan-Meier patient survival curves. The results highlighted the dual role of PDIA1 in suppressing carcinogenesis in the ERα(+) breast cancer patients by negatively regulating the response to reactive oxygen species (ROS) and promoting carcinogenesis by inducing cell cycle progression. In the ERα(−) breast cancer patients, PDIA1 prevented tumor development by modulating NF-κB and p53 activity and cell migration and induced breast cancer progression through control of cytokine signaling and the immune response. The findings reported in this study shed light on the differential pathways regulating carcinogenesis in ERα(+) and ERα(−) breast cancer patients and could help identify therapeutic targets selectively effective in ERα(+) vs. ERα(−) patients.

MicroRNA‑199a/b‑5p inhibits endometrial cancer cell metastasis and invasion by targeting FAM83B in the epithelial‑to‑mesenchymal transition signaling pathway

Our previous study demonstrated the role of family with sequence similarity 83, member B (FAM83B) in endometrial cancer tumorigenesis and metastasis. FAM83B is involved in epithelial‑to‑mesenchymal transition (EMT). However, the regulatory network of EMT, which promotes endometrial cancer cell metastasis, involving microRNAs (miRNAs/miRs) and FAM83B, has not been elucidated. To investigate the potential mechanism underlying miR‑199a/b‑5p in endometrial cancer, the effect of miR‑199a/b‑5p and its targeted FAM83B gene on the biological behaviour of endometrial cancer cells was assessed. The Gene Expression Omnibus dataset analysis results revealed that the expression levels of 150 miRNAs in non‑cancerous endometrial tissues were upregulated compared with those in endometrial cancer tissues. TargetScan predicted that the nucleotides 672‑679 of FAM83B 3'‑untranslated region (UTR) were the target sites of miR‑199a/b‑5p. The differentially expressed miRNAs were enriched in several Kyoto Encyclopedia of Genes and Genomes pathways. Reverse transcription‑quantitative PCR analysis revealed that the expression levels of miR‑199a/b‑5p in the endometrial non‑cancerous cell lines were significantly upregulated compared with those in the six endometrial cancer cell lines. miR‑199a/b‑5p inhibited the EMT signaling pathway by regulating the expression levels of E‑cadherin, N‑cadherin, Snail, α‑smooth muscle actin, vimentin and Twist. This suggested that miR‑199a/b‑5p inhibited endometrial cancer cell proliferation and migration through the inhibition of the EMT signaling pathway. Furthermore, the nucleotides 672‑679 of the FAM83B 3'‑UTR were demonstrated to be the binding site of miR‑199a/b‑5p. These results suggested that miR‑199a/b‑5p inhibited endometrial cancer cell proliferation and metastasis by targeting the 3'‑UTR of FAM83B, which is involved in the EMT signaling pathway.

Protein tyrosine phosphatases in cell adhesion

Adhesive structures between cells and with the surrounding matrix are essential for the development of multicellular organisms. In addition to providing mechanical integrity, they are key signalling centres providing feedback on the extracellular environment to the cell interior, and vice versa. During development, mitosis and repair, cell adhesions must undergo extensive remodelling. Post-translational modifications of proteins within these complexes serve as switches for activity. Tyrosine phosphorylation is an important modification in cell adhesion that is dynamically regulated by the protein tyrosine phosphatases (PTPs) and protein tyrosine kinases. Several PTPs are implicated in the assembly and maintenance of cell adhesions, however, their signalling functions remain poorly defined. The PTPs can act by directly dephosphorylating adhesive complex components or function as scaffolds. In this review, we will focus on human PTPs and discuss their individual roles in major adhesion complexes, as well as Hippo signalling. We have collated PTP interactome and cell adhesome datasets, which reveal extensive connections between PTPs and cell adhesions that are relatively unexplored. Finally, we reflect on the dysregulation of PTPs and cell adhesions in disease.

Anti-oncogene PTPN13 inactivation by hepatitis B virus X protein counteracts IGF2BP1 to promote hepatocellular carcinoma progression

Hepatitis B x protein (HBx) affects cellular protein expression and participates in the tumorigenesis and progression of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). Metabolic reprogramming contributed to the HCC development, but its role in HBV-related HCC remains largely unclear. Tyrosine-protein phosphatase nonreceptor type 13 (PTPN13) is a significant regulator in tumor development, however, its specific role in hepatocarcinogenesis remains to be explored. Here, we found that decreased PTPN13 expression was associated with HBV/HBx. Patients with low PTPN13 expression showed a poor prognosis. Functional assays revealed that PTPN13 inhibited proliferation and tumorigenesis in vitro and in vivo. Further mechanistic studies indicated that HBx inhibited PTPN13 expression by upregulating the expression of DNMT3A and interacting with DNMT3A. Furthermore, we found that DNMT3A bound to the PTPN13 promoter (-343 to -313 bp) in an epigenetically controlled manner associated with elevated DNA methylation and then inhibited PTPN13 transcription. In addition, we identified IGF2BP1 as a novel PTPN13-interacting gene and demonstrated that PTPN13 influences c-Myc expression by directly and competitively binding to IGF2BP1 to decrease the intracellular concentration of functional IGF2BP1. Overexpressing PTPN13 promoted c-Myc mRNA degradation independent of the protein tyrosine phosphatase (PTP) activity of PTPN13. Importantly, we discovered that the PTPN13-IGF2BP1-c-Myc axis was important for cancer cell growth through promoting metabolic reprogramming. We verified the significant negative correlations between PTPN13 expression and c-Myc, PSPH, and SLC7A1 expression in clinical HCC tissue samples. In summary, our findings demonstrate that PTPN13 is a novel regulator of HBV-related hepatocarcinogenesis and may play an important role in HCC. PTPN13 may serve as a prognostic marker and therapeutic target in HBV-related HCC patients.

Oxidative Stress-Induced circHBEGF Promotes Extracellular Matrix Production via Regulating miR-646/EGFR in Human Trabecular Meshwork Cells

Primary open-angle glaucoma (POAG), a leading cause of irreversible vision loss, presents with increased prevalence and a higher degree of clinical severity in the world. Growing evidence has shown that ncRNAs are involved in the fibrotic process, which is thought to be the proegumenal cause of POAG. Here, we screened out a differentially expressed circRNA (named circHBEGF) in human trabecular meshwork cells (HTMCs) under oxidative stress, which is spliced from pre-HBEGF. circHBEGF promotes the expression of extracellular matrix (ECM) genes (fibronectin and collagen I). Further studies revealed that circHBEGF could competitively bind to miR-646 as a miRNA sponge to regulate EGFR expression in HTMCs. Importantly, HBEGF can also activate EGF signaling pathways, through which can transcriptionally activate ECM genes in HTMCs. In summary, this study investigates the functions and molecular mechanisms of oxidative stress-induced circHBEGF in the regulation of ECM production in HTMCs through the miR646/EGFR pathway. These findings further elucidate the pathogenic mechanism and may identify novel targets for the molecular therapy of POAG.

Down-regulation of lncRNA HCG11 promotes cell proliferation of oral squamous cell carcinoma through sponging miR-455-5p

BACKGROUND

As a type of head and neck squamous cell carcinoma (HNSCC), oral squamous cell carcinoma (OSCC) has a high incidence and low survival rate. Frequent deletion of protein tyrosine phosphatase receptor type sigma (PTPRS) has been found in HNSCC. Long non-coding RNA (lncRNA) HCG11 and miR-455-5p have been reported to be involved in several cancers, in which miR-455-5p was found to be up-regulated in the OSCC. However, the role of HCG11 in OSCC development is still unclear.

METHODS

Several co-transfection systems were established to explore the regulation of HCG11 on OSCC cells. Cell proliferation was evaluated by the MTT assay, flow cytometry of cell cycle distribution, immunofluorescence of Ki67 and western blotting. A dual luciferase reporter assay was performed to verify the binding effects of miR-455-5p on HCG11 and PTPRS. The role of HCG11 knockdown in OSCC cell growth was also confirmed by nude mouse tumorigenicity assay in vivo.

RESULTS

Knockdown of HCG11 increased OSCC cell proliferation, as indicated by enhanced cell vitalities over time, increased G1/S transition and Ki67 levels. Furthermore, lncRNA HCG11 was shown to negatively regulate miR-455-5p and miR-455-5p targeted PTPRS directly to affect its downstream indicators, which can further modulate OSCC cell proliferation and growth. The results obtained in vivo confirmed that HCG11 knockdown promoted OSCC cell growth.

CONCLUSIONS

The lncRNA HCG11/miR-R-455-5p axis can be considered as an upstream signalling circuit of PTPRS with respect to regulating its activity and downstream pathways to further influence the progression of OSCC. This finding may provide a novel RNA-based therapeutic target for OSCC treatment.

Protein Tyrosine Phosphatase Receptor S Acts as a Metastatic Suppressor in Malignant Peripheral Nerve Sheath Tumor via Profilin 1-Induced Epithelial-Mesenchymal Transition

Malignant peripheral nerve sheath tumors (MPNST) are aggressive sarcomas with over half of cases developed in the context of neurofibromatosis type 1. Surgical resection is the only effective therapy for MPNST. The prognosis is very dismal once recurrence or metastasis occurs. Epithelial-mesenchymal transition (EMT) is a key process of recurrence and metastasis involving reorganizations of the actin cytoskeleton and actin-binding proteins (ABP) play a non-negligible role. Protein tyrosine phosphatase receptor S (PTPRS), a tumor suppressor previously reported in colorectal cancer, hepatocellular carcinoma and head and neck cancer, is thought to mediate cell migration and invasion by downregulation of EMT. However, its role in MPNST remains unknown. In the present study, by using tissue microarray we demonstrated low expression of PTPRS was related to poor prognosis in MPNST. Knockdown of PTPRS in MPNST cell lines increased migration/invasion and EMT processes were induced with increased N-cadherin and decreased E-cadherin, which indicated PTPRS may serve as a tumor suppressor in MPNST. In addition, we tested all EMT related ABP and found profilin 1 was significantly elevated in PTPRS downregulated MPNST cell lines. As a member of actin-binding proteins, profilins are regulators of actin polymerization and contribute to cell motility and invasion, which have been reported to be responsible for EMT. Moreover, results showed that downregulation of profilin 1 could restore the EMT processes caused by PTPRS downregulation in vitro and in vivo. Furthermore, high expression of profilin 1 was significantly associated with dismal prognosis. These results highlighted PTPRS served as a potential tumor suppressor in the recurrence and metastasis of MPNST via profilin 1 induced EMT processes and it might provide potential targets for future clinical therapeutics.

PTPRε Acts as a Metastatic Promoter in Hepatocellular Carcinoma by Facilitating Recruitment of SMAD3 to TGF-β Receptor 1

BACKGROUND AND AIMS

Transforming growth factor beta (TGF-β) suppresses early stages of tumorigenesis, but contributes to the migration and metastasis of cancer cells. However, the role of TGF-β signaling in invasive prometastatic hepatocellular carcinoma (HCC) is poorly understood. In this study, we investigated the roles of canonical TGF-β/mothers against decapentaplegic homolog 3 (SMAD3) signaling and identified downstream effectors on HCC migration and metastasis.

APPROACH AND RESULTS

By using in vitro trans-well migration and invasion assays and in vivo metastasis models, we demonstrated that SMAD3 and protein tyrosine phosphatase receptor epsilon (PTPRε) promote migration, invasion, and metastasis of HCC cells in vitro and in vivo. Further mechanistic studies revealed that, following TGF-β stimulation, SMAD3 binds directly to PTPRε promoters to activate its expression. PTPRε interacts with TGFBR1/SMAD3 and facilitates recruitment of SMAD3 to TGFBR1, resulting in a sustained SMAD3 activation status. The tyrosine phosphatase activity of PTPRε is important for binding with TGFBR1, recruitment and activation of SMAD3, and its prometastatic role in vitro. A positive correlation between pSMAD3/SMAD3 and PTPRε expression was determined in HCC samples, and high expression of SMAD3 or PTPRε was associated with poor prognosis of patients with HCC.

CONCLUSIONS

PTPRε positive feedback regulates TGF-β/SMAD3 signaling to promote HCC metastasis.

The tumor suppressor PTPRK promotes ZNRF3 internalization and is required for Wnt inhibition in the Spemann organizer

A hallmark of Spemann organizer function is its expression of Wnt antagonists that regulate axial embryonic patterning. Here we identify the tumor suppressor Protein tyrosine phosphatase receptor-type kappa (PTPRK), as a Wnt inhibitor in human cancer cells and in the Spemann organizer of Xenopus embryos. We show that PTPRK acts via the transmembrane E3 ubiquitin ligase ZNRF3, a negative regulator of Wnt signaling promoting Wnt receptor degradation, which is also expressed in the organizer. Deficiency of Xenopus Ptprk increases Wnt signaling, leading to reduced expression of Spemann organizer effector genes and inducing head and axial defects. We identify a '4Y' endocytic signal in ZNRF3, which PTPRK maintains unphosphorylated to promote Wnt receptor depletion. Our discovery of PTPRK as a negative regulator of Wnt receptor turnover provides a rationale for its tumor suppressive function and reveals that in PTPRK-RSPO3 recurrent cancer fusions both fusion partners, in fact, encode ZNRF3 regulators.

How human and other animals form distinct head- and tail-ends as embryos is a fundamental question in biology. The fertilized eggs of the African clawed frog (also known as Xenopus) become embryos and grow into tadpoles within two days. This rapid growth makes Xenopus particularly suitable as a model to study how animals with backbones form their body plans.

In Xenopus embryos, a small group of cells known as the Spemann organizer plays a pivotal role in forming the body plan. It produces several enzymes known as Wnt inhibitors that repress a signal pathway known as Wnt signaling to determine the head- and tail-ends of the embryo.

Chang, Kim et al. searched for new Wnt inhibitors in the Spemann organizer of Xenopus embryos. The experiments revealed that the Spemann organizer produced an enzyme known as PTPRK that was essential to permit the head-to-tail patterning of the brain. PTPRK inhibited Wnt signaling by activating another enzyme known as ZNRF3.

Previous studies have shown that defects in Wnt signaling and in the activities of PTPRK and ZNRF3 are involved in colon cancer in mammals. Thus, these findings may help to develop new approaches for treating cancer in the future.

PTPRS drives adaptive resistance to MEK/ERK inhibitors through SRC

PTPRS is the most commonly mutated receptor tyrosine phosphatase in colorectal cancer (CRC). PTPRS has been shown to directly affect ERK and regulate its activation and nuclear localization. Here we identify that PTPRS may play a significant role in developing adaptive resistance to MEK/ERK inhibitors (MEKi/ERKi) through SRC activation. Moreover, we demonstrate a new clinical approach to averting adaptive resistance through the use of the SRC inhibitor, dasatinib. Our data suggest the potential for dasatinib to enhance the efficacy of MEKi and ERKi by preventing adaptive resistance pathways operating through SRC.

ERα-mediated alterations in circ_0023642 and miR-490-5p signaling suppress bladder cancer invasion

Epidemiological studies show obvious gender differences in the incidence and the prognosis of bladder cancer (BCa). Estrogen receptor alpha (ERα) was recently shown to play a protective role in BCa. However, the mechanisms by which ERα mediates BCa progression need to be further elucidated. In the present study, we explored the mechanisms by which ERα inhibits BCa invasion by modulating circRNA levels. ERα suppressed BCa invasion by decreasing circ_0023642 expression. Chromatin immunoprecipitation (ChIP) and luciferase assays revealed that ERα reduced circ_0023642 expression by regulating the expression of its host gene, UVRAG, at the transcriptional level. ERα decreased circ_0023642 levels and subsequently increased miR-490-5p expression, resulting in decreased EGFR expression to suppress BCa cell invasion. Circ_0023642 was demonstrated to directly bind to miR-490-5p. Notably, miR-490-5p regulated EGFR expression by binding to the miR-490-5p-binding site located in the 3′-untranslated region (UTR) of the EGFR mRNA. Preclinical studies using an in vivo mouse model also confirmed that this ERα/circ_0023642/miR-490-5p/EGFR signaling pathway suppressed BCa progression. Altogether, this newly identified pathway may serve as the basis for developing novel therapeutic strategies to treat BCa.

Afatinib, an EGFR inhibitor, decreases EMT and tumorigenesis of Huh‑7 cells by regulating the ERK‑VEGF/MMP9 signaling pathway

Transcatheter arterial embolization (TAE) therapy has been used in the treatment of inoperable hepatocellular carcinoma (HCC). However, tumor recurrence and metastasis are common in patients after TAE, and these processes may be caused by circulating tumor cells (CTCs). Epithelial-mesenchymal transition (EMT) serves important roles in CTCs, and abnormal expression and activation of epidermal growth factor receptor (EGFR) is common in cancer cells. Afatinib is an EGFR-tyrosine kinase inhibitor (TKI). The present study aimed to investigate the effects of afatinib on EMT and tumorigenesis in HCC cells. Western blot analysis suggested that afatinib was able to effectively suppress overactivation of EGFR. Moreover, the expression levels of EMT- and metastasis-associated genes were found to be modulated by afatinib through EGFR inhibition. In addition, Cell Counting Kit-8 and Transwell assays suggested that the viability, migration and invasion of HCC cells were inhibited by afatinib through EGFR inhibition. Furthermore, the activity of the ERK signaling pathway and the expression levels of vascular endothelial growth factor (VEGF) and matrix metalloproteinase 9 (MMP9) were decreased following treatment with afatinib in vitro. Collectively, the present results suggested that the inhibitory effects of afatinib on EMT and tumorigenesis may be associated with the ERK-VEGF/MMP9 signaling pathway. The present study provides new insights into understanding the mechanism underlying HCC and may facilitate the development of novel therapeutic strategies to treat HCC recurrence.

Prognostic and Therapeutic Implications of Microvascular Invasion in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a morbid condition for which surgical and ablative therapy are the only options for cure. Nonetheless, over half of patients treated with an R0 resection will develop recurrence. Early recurrences within 2 years after resection are thought to be due to the presence of residual microscopic disease, while late recurrences > 2 years after resection are thought to be de novo metachronous HCCs arising in chronically injured liver tissue. Microvascular invasion (MVI) is defined as the presence of micrometastatic HCC emboli within the vessels of the liver, and is a critical determinant of early recurrence and survival. In this review, we summarize the pathogenesis and clinical relevance of MVI, which correlates with adverse biological features, including high grade, large tumor size, and epithelial-mesenchymal transition. Multiple classification schemas have been proposed to capture the heterogeneous features of MVI that are associated with prognosis. However, currently, MVI can only be determined based on surgical specimens, limiting its clinical applicability. Going forward, advances in axial imaging technologies, molecular characterization of biopsy tissue, and novel serum biomarkers hold promise as future methods for non-invasive MVI detection. Ultimately, MVI status may be used to help clinicians determine treatment plans, particularly with respect to surgical intervention, and to provide more accurate prognostication.

SHP-1 Acts as a Tumor Suppressor in Hepatocarcinogenesis and HCC Progression

Src homology region 2 (SH2) domain-containing phosphatase 1 (SHP-1, also known as PTPN6) is a nonreceptor protein tyrosine phosphatase that acts as a negative regulator of inflammation. Emerging evidence indicates that SHP-1 plays a role in inhibiting the progression of hepatocellular carcinoma (HCC). However, the role of SHP-1 in hepatocarcinogenesis remains unknown. Here, we find that levels of SHP-1 are significantly downregulated in human HCC tissues compared with those in noncancerous tissues (P < 0.001) and inversely correlate with tumor diameters (r = -0.4130, P = 0.0002) and serum α-fetoprotein levels (P = 0.047). Reduced SHP-1 expression was associated with shorter overall survival of patients with HCC with HBV infection. Overexpression of SHP-1 suppressed proliferation, migration, invasion, and tumorigenicity of HCC cells, whereas knockdown of SHP-1 enhanced the malignant phenotype. Moreover, knockout of Ptpn6 in hepatocytes (Ptpn6^HKO ) enhanced hepatocarcinogenesis induced by diethylnitrosamine (DEN) as well as metastasis of primary liver cancer in mice. Furthermore, systemic delivery of SHP-1 by an adenovirus expression vector exerted a therapeutic effect in an orthotopic model of HCC in NOD/SCID mice and DEN-induced primary liver cancers in Ptpn6^HKO mice. In addition, SHP-1 inhibited the activation of JAK/STAT, NF-κB, and AKT signaling pathways, but not the MAPK pathway in primary hepatocytes from DEN-treated mice and human HCC cells. Together, our data implicate SHP-1 as a tumor suppressor of hepatocarcinogenesis and HCC progression and propose it as a novel prognostic biomarker and therapeutic target of HCC.Significance: The nonreceptor protein tyrosine phosphatase SHP-1 acts as a tumor suppressor in hepatocellular carcinoma. Cancer Res; 78(16); 4680-91. ©2018 AACR.

Peritumoral monocytes induce cancer cell autophagy to facilitate the progression of human hepatocellular carcinoma

Macroautophagy/autophagy is an important catabolic process mediating cellular homeostasis and plays critical roles in cancer development. Whereas autophagy has been widely studied in various pathological models, little is known about the distribution, clinical significance and regulatory mechanism of this process in human hepatocellular carcinoma (HCC). In the present study, we found that tumor tissues exhibited significantly increased levels of autophagy compared with non-tumor tissues, and cancer cells with higher levels of autophagy were predominantly enriched in the invading edge regions of human HCC. Increased MAP1LC3B/LC3B expression in the invading edge regions was significantly correlated with a higher density of closely located monocytes, and TNF and IL1B derived from tumor-activated monocytes synergistically induced cancer cell autophagy in the invading edge regions of HCC. Monocyte-elicited autophagy induced the epithelial-mesenchymal transition (EMT) of cancer cells and promoted tumor metastasis by activating the NFKB-SNAI1 signaling pathway. Moreover, the increase of LC3B⁺ cancer cells in the invading edge areas was associated with high mortality and reduced survival of patients with HCC. These findings indicated that cancer cell autophagy is regulated by a collaborative interaction between tumor and immune cell components in distinct HCC microenvironments, thus allowing the inflammatory monocytes to be rerouted in a tumor-promoting direction.

Inhibition of stromal-interacting molecule 1-mediated store-operated Ca2+ entry as a novel strategy for the treatment of acquired imatinib-resistant gastrointestinal stromal tumors

Imatinib has revolutionized the treatment of gastrointestinal stromal tumors (GIST); however, primary and secondary resistance to imatinib is still a major cause of treatment failure. Multiple mechanisms are involved in this progression. In the present study, we reported a novel mechanism for the acquired resistance to imatinib, which was induced by enhanced Ca²⁺ influx via stromal‐interacting molecule 1 (STIM1)‐mediated store‐operated Ca²⁺ entry (SOCE). We found that the STIM1 expression level was related to the acquired resistance to imatinib in our studied cohort. The function of STIM1 in imatinib‐resistant GIST cells was also confirmed both in vivo and in vitro. The results showed that STIM1 overexpression contributed to SOCE and drug response in imatinib‐sensitive GIST cells. Blockage of SOCE by STIM1 knockdown suppressed the proliferation of imatinib‐resistant GIST cell lines and xenografts. In addition, STIM1‐mediated SOCE exerted an antiapoptotic effect via the MEK/ERK pathway. The results from this study provide a basis for further research into potential novel therapeutic strategies in acquired imatinib‐resistant GIST.

PTPRS Regulates Colorectal Cancer RAS Pathway Activity by Inactivating Erk and Preventing Its Nuclear Translocation

Colorectal cancer (CRC) growth and progression is frequently driven by RAS pathway activation through upstream growth factor receptor activation or through mutational activation of KRAS or BRAF. Here we describe an additional mechanism by which the RAS pathway may be modulated in CRC. PTPRS, a receptor-type protein tyrosine phosphatase, appears to regulate RAS pathway activation through ERK. PTPRS modulates ERK phosphorylation and subsequent translocation to the nucleus. Native mutations in PTPRS, present in ~10% of CRC, may reduce its phosphatase activity while increasing ERK activation and downstream transcriptional signaling.

The Roles of Protein Tyrosine Phosphatases in Hepatocellular Carcinoma

The protein tyrosine phosphatase (PTP) family is involved in multiple cellular functions and plays an important role in various pathological and physiological processes. In many chronic diseases, for example cancer, PTP is a potential therapeutic target for cancer treatment. In the last two decades, dozens of PTP inhibitors which specifically target individual PTP molecules were developed as therapeutic agents. Hepatocellular carcinoma (HCC) is one of the most common malignant tumors and is the second most lethal cancer worldwide due to a lack of effective therapies. Recent studies have unveiled both oncogenic and tumor suppressive functions of PTP in HCC. Here, we review the current knowledge on the involvement of PTP in HCC and further discuss the possibility of targeting PTP in HCC.

Protein tyrosine phosphatase PTP4A1 promotes proliferation and epithelial-mesenchymal transition in intrahepatic cholangiocarcinoma via the PI3K/AKT pathway

The protein tyrosine phosphatase PTP4A1 is a key molecule that activates tyrosine phosphorylation, which is important for cancer progression and metastasis. However, the clinical implications and biological function of PTP4A1 in intrahepatic cholangiocarcinoma (ICC) remains unknown. Here, we showed that PTP4A1 was frequently overexpressed in ICC versus adjacent non-tumor tissues. This overexpression significantly correlated with aggressive tumor characteristics like the presence of lymph node metastasis and advanced tumor stages. Survival analysis further indicated that high PTP4A1 expression was significantly and independently associated with worse survival and increased recurrence in ICC patients. Moreover, through forced overexpression and knock-down of PTPT4A1, we demonstrated that PTP4A1 could significantly promote ICC cells proliferation, colony formation, migration, and invasion in vitro, and markedly enhance tumor progression in vivo. Mechanistically, PTP4A1 was involved in PI3K/AKT signaling and its downstream molecules, such as phosphorylation level of GSK3β and up-regulation of CyclinD1, in ICC cells to promote proliferation. Importantly, PTP4A1 induced ICC cells invasion was through activating PI3K/AKT signaling controlled epithelial-mesenchymal transition (EMT) process by up-regulating Zeb1 and Snail. Thus, PTP4A1 may serve as a potential oncogene that was a valuable prognostic biomarker and therapeutic target for ICC.

NEK2 promotes hepatocellular carcinoma migration and invasion through modulation of the epithelial-mesenchymal transition

Never in mitosis gene-A (NIMA)-related expressed kinase 2 (NEK2) has been recently reported to play a role in tumor progression, drug resistance and tumorigenesis. However, little is known about the effects of NEK2 in hepatocellular carcinoma (HCC) metastasis and the underlying mechanism. NEK2 expression levels were examined by immunochemistry, qRT-PCR and western blot analyses in HCC cell lines and HCC tissues. A Transwell assay was used to determine the migration and invasion capacity of NEK2-silenced or NEK2-overexpressing HCC cells. Cell proliferation was investigated by MTT [(3-(4,5)-dimethylthiazol(-z-y1)-3,5-di-phenytetrazolium bromide] assay. The expression levels of epithelial-mesenchymal transition (EMT) markers in NEK2-silenced or NEK2-overexpressing HCC cells were examined by western blot analyses and qRT-PCR. The correlations between NEK2 expression and clinicopathological characteristics were further analyzed. Gene microarray was further used to analyze the effect of NEK2 expression on downstream cell signals. Our study showed that NEK2 was overexpressed in human HCC (37.84%; 98/259). NEK2 overexpression was significantly associated with liver non-capsulation and predicted poor survival outcomes in HCC patients after hepatectomy. In addition, NEK2 significantly enhanced HCC cell invasive ability. Mechanistically, we found that the epithelial-mesenchymal transition (EMT) plays a pivotal role in the NEK2-mediated promotion of HCC cell invasion. Furthermore, we provided evidence that signaling through the Wnt, NF-κB, focal adhesion, VEGF, Hippo and p53 pathways may be downstream of NEK2. Our findings highlight the importance of NEK2 in HCC metastasis and suggest that NEK2 is a reliable prognostic marker for HCC patients after hepatectomy.

Tumor suppressive protein phosphatases in human cancer: Emerging targets for therapeutic intervention and tumor stratification

Aberrant protein phosphorylation is one of the hallmarks of cancer cells, and in many cases a prerequisite to sustain tumor development and progression. Like protein kinases, protein phosphatases are key regulators of cell signaling. However, their contribution to aberrant signaling in cancer cells is overall less well appreciated, and therefore, their clinical potential remains largely unexploited. In this review, we provide an overview of tumor suppressive protein phosphatases in human cancer. Along their mechanisms of inactivation in defined cancer contexts, we give an overview of their functional roles in diverse signaling pathways that contribute to their tumor suppressive abilities. Finally, we discuss their emerging roles as predictive or prognostic markers, their potential as synthetic lethality targets, and the current feasibility of their reactivation with pharmacologic compounds as promising new cancer therapies. We conclude that their inclusion in clinical practice has obvious potential to significantly improve therapeutic outcome in various ways, and should now definitely be pushed forward.

cPLA2α activates PI3K/AKT and inhibits Smad2/3 during epithelial-mesenchymal transition of hepatocellular carcinoma cells

Cytosolic phospholipase A2α (cPLA2α), a key phospholipase that regulates lipid metabolism, plays an important role in tumor progression. In the present study of hepatocellular carcinoma (HCC), cPLA2α was overexpressed in highly metastatic HCC cell lines. Immunohistochemical staining showed increased levels of cPLA2α at the invasive edges of HCC, and a clinicopathological analysis of samples from 111 patients revealed that its expression level was linked with micro-vascular invasion and cirrhosis. Knockdown of cPLA2α inhibited migration, probably due to its role in actin polymerization. Overexpression of cPLA2α promoted cell migration and invasion. Based on the mechanistic analysis, our data suggested that cPLA2α mediate epidermal growth factor (EGF) induced epithelial-mesenchymal transition (EMT) through PI3K/AKT/ERK pathway. cPLA2α activity was required for the transforming growth factor-(TGF)-β-induced EMT. However, cPLA2α inhibited Smad2/3 activation and promoted the activation of the PI3K/AKT/ERK pathway. A xenograft tumor transplant model confirmed the role of cPLA2α in HCC invasion and metastasis. Based on the mechanistic analysis, cPLA2α mediated both EGF- and TGF-β-induced EMT, which are essential for HCC metastasis. cPLA2α is a potentially target for novel therapies of HCC.

miR-539 inhibits FSCN1 expression and suppresses hepatocellular carcinoma migration and invasion

Increasing evidence indicates that the dysregulation of miRNAs that act as tumor suppressors or oncogenes is involved in tumorigenesis. However, the role of miR-539 in hepatocellular carcinoma (HCC) has not been well investigated. Quantitative RT-PCR (qRT-PCR), proliferation assay, colony formation assay, migration and invasion assays, western blotting, and xenograft tumor growth models were performed to assess the expression levels and functions of miR-539 in HCC. Luciferase reporter assays, qRT-PCR, western blotting, and immunohistochemistry were used to identify and verify the targets of miR-539. miR-539 was significantly downregulated in HCC cell lines and tissue samples. Ectopic expression of miR-539 inhibited cell viability, proliferation, migration, and invasion in vitro and suppressed xenograft tumor growth in vivo. Fascin homologue 1 (FSCN1) was verified as a direct target of miR-539, and overexpression of FSCN1 promoted HCC cell migration and invasion. miR-539 acts as a novel tumor suppressor in the development and progression of HCC by targeting FSCN1, providing new insight into the mechanisms of HCC carcinogenesis and suggesting that miR-539 may be a therapeutic target.

E3 Ubiquitin Ligase Cbl-b Prevents Tumor Metastasis by Maintaining the Epithelial Phenotype in Multiple Drug-Resistant Gastric and Breast Cancer Cells

Multiple drug resistance (MDR) and metastasis are two major factors that contribute to the failure of cancer treatment. However, the relationship between MDR and metastasis has not been characterized. Additionally, the role of the E3 ubiquitin ligase Cbl-b in metastasis of MDR gastric and breast cancer is not well known. In the present study, we found that MDR gastric and breast cancer cells possess a typical mesenchymal phenotype and enhanced cell migration capacity. Additionally, Cbl-b is poorly expressed in MDR gastric and breast cancer cells. In MDR gastric adenocarcinoma tissues, gastric cancer patients with low Cbl-b expression were more likely to have tumor invasion (P = .016) and lymph node metastasis (P = .007). Moreover, overexpression of Cbl-b reduced cell migration in MDR cell cultures both in vitro and in vivo. Cbl-b overexpression also prevented EMT by inducing ubiquitination and degradation of EGFR, leading to inhibition of the EGFR-ERK/Akt-miR-200c-ZEB1 axis. However, further overexpression of EGFR on a background of Cbl-b overexpression restored both the mesenchymal phenotype and cell migration capacity of MDR gastric and breast cancer cells. These results suggest that Cbl-b is an important factor for maintenance of the epithelial phenotype and inhibition of cell migration in MDR gastric and breast cancer cells.

MicroRNA-29c-5p suppresses gallbladder carcinoma progression by directly targeting CPEB4 and inhibiting the MAPK pathway

Gallbladder cancer (GBC) is a leading cause of cancer-related deaths worldwide, and its prognosis remains poor, with a 5-year survival rate of ~5%. Given the crucial role of microRNAs (miRNAs) in cancer metastasis, we aimed to analyze the expression and function of the metastasis-associated miRNA miR-29c-5p in GBC.We validated that expression of miR-29c-5p was significantly downregulated in GBC and was closely associated with lymph node metastasis, overall survival and disease-free survival in 40 GBC patients who were followed clinically. Ectopic overexpression of miR-29c-5p dramatically repressed proliferation, metastasis, and colony formation and induced apoptosis in vitro, and it suppressed tumorigenicity in vivo through the MAPK pathway. Cytoplasmic polyadenylation element binding protein 4 (CPEB4) was identified as a critical effector target of miR-29c-5p. Enforced expression of miR-29c-5p significantly inhibited the expression of CPEB4, and restoration of CPEB4 expression reversed the inhibitory effects of miR-29c-5p on GBC cell proliferation and metastasis. Transforming growth factor-β (TGF-β) upregulated CPEB4 by downregulating miR-29c-5p, leading to MAPK pathway activation. In conclusion, the TGF-β/miR-29c-5p/CPEB4 axis has a pivotal role in the pathogenesis and poor prognosis of GBC, suggesting that miR-29c-5p is a tumor-suppressive miRNA that may serve as potential prognostic biomarker or therapeutic target for GBC.

Tripartite motif containing 62 is a novel prognostic marker and suppresses tumor metastasis via c-Jun/Slug signaling-mediated epithelial-mesenchymal transition in cervical cancer

Background

TRIM62 (tripartite motif containing 62) has been found to act as a tumor suppressor of several cancers. However, its precise biological role and related mechanism remain unknown in cervical cancer (CC).

Methods

Quantitative Real-time PCR and western blot were adopted to detect the mRNA and protein expression level of TRIM62 in both human CC cell lines and tissues. Immunohistochemistry was used to measure the TRIM62 expression in 30 normal cervical and 189 CC tissues. Univariate and multivariate Cox regression analyses and Kaplan–Meier survival analyses performed to investigate the association between TRIM62 expression and CC patients’ prognosis. The effect of TRIM62 on CC growth and metastasis was studied in vitro and in vivo. Multi-pathway reporter array were utilized to identify the potential signaling manipulated by TRIM62.

Results

TRIM62 was frequently down-regulated in both human CC cells and tissues. Low expression of TRIM62 in CC tissues was associated with aggressive clinicopathological features of CC patients. In addition, TRIM62 was also an independent poor prognostic factor for overall and disease-free survival of CC patients after surgery. Moreover, enforced expression of TRIM62 in CC cells significantly inhibited their abilities of proliferation, migration and invasion in vitro. Besides, subcutaneous xenograft tumor model and xenograft mouse metastatic model respectively displayed that TRIM62 impeded the growth and metastasis of CC in vivo. Furthermore, mechanism study exhibited that TRIM62 could suppress epithelial-mesenchymal transition (EMT) by inhibiting c-Jun/Slug signaling. The inhibitory role of TRIM62 in tumor proliferation might be through regulating cell cycle related proteins CyclinD1 and P27 by targeting c-Jun.

Conclusion

TRIM62 is a potential prognostic biomarker in CC and suppresses metastasis of CC via inhibiting c-Jun/Slug signaling-mediated EMT.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-016-0445-5) contains supplementary material, which is available to authorized users.

Role of epithelial to mesenchymal transition in hepatocellular carcinoma

The epithelial to mesenchymal transition (EMT) is a multistep biological process whereby epithelial cells change in plasticity by transient de-differentiation into a mesenchymal phenotype. EMT and its reversal, mesenchymal to epithelial transition (MET), essentially occur during embryogenetic morphogenesis and have been increasingly described in fibrosis and cancer during the last decade. In carcinoma progression, EMT plays a crucial role in early steps of metastasis when cells lose cell-cell contacts due to ablation of E-cadherin and acquire increased motility to spread into surrounding or distant tissues. Epithelial plasticity has become a hot issue in hepatocellular carcinoma (HCC), as strong inducers of EMT such as transforming growth factor-β are able to orchestrate both fibrogenesis and carcinogenesis, showing rising cytokine levels in cirrhosis and late stage HCC. In this review, we consider the significance of EMT-MET in malignant hepatocytes as well as changes in the plasticity of hepatic stellate cells for cellular heterogeneity of HCC, and further aim at explaining the current limiting insights into EMT by snapshot analyses of HCC tissues. Recent advances in the identification of clinically relevant mechanisms that impinge on important EMT-transcription factors, as well as on miRNAs causing EMT signatures and HCC progression are highlighted. In addition, we draw particular attention to framing EMT in the context of potential clinical relevance for HCC patients. We conclude that some aspects of EMT are still elusive and further studies are required to better link the clinical management of HCC with biomarkers and targeted therapies related to EMT.

Nutritional Epigenetics and the Prevention of Hepatocellular Carcinoma with Bioactive Food Constituents

Hepatocellular carcinoma (HCC) is an aggressive and life-threatening disease often diagnosed at intermediate or advanced stages, which substantially limits therapeutic approaches to its successful treatment. This indicates that the prevention of HCC may be the most promising strategy in reducing its incidence and mortality. Emerging evidence indicates that numerous nutrients and nonnutrient dietary bioactive components can reduce the occurrence and/or delay the development of HCC through modifications of deregulated epigenetic mechanisms. This review examines the existing knowledge on the epigenetic mechanism-based studies in in vitro and in vivo models of HCC on the chemopreventive potential of epigenetic food components, including dietary methyl-group donors, epigallocatechin-3-gallate, sodium butyrate, resveratrol, curcumin, and sulforaphane, on liver carcinogenesis. Future direction and potential challenges in the effective use of bioactive food constituents in the prevention of HCC are highlighted and discussed.

An integrin beta4-EGFR unit promotes hepatocellular carcinoma lung metastases by enhancing anchorage independence through activation of FAK-AKT pathway

Anoikis, a form of programmed cell death, occurs when the cells are detached from the appropriate extracellular matrix. Anoikis resistance or anchorage independence is necessary for distant metastases of cancer. The mechanisms by which hepatocellular carcinoma (HCC) cells become resistant to anoikis are not fully understood. Integrin beta4 (ITGB4, also known as CD104) is associated with progression of many human cancers. In this study, we demonstrate that ITGB4 is over-expressed in HCC tissues and aggressive HCC cell lines. To explore the role of ITGB4 in HCC, we inhibited its expression using small interfering RNA in two HCC cell lines: HCCLM3 and HLF. We show that knockdown of ITGB4 significantly enhanced susceptibility to anoikis through inhibition of AKT/PKB signaling. Moreover, ITGB4 interacts with epidermal growth factor receptor (EGFR) in a ligand independent manner. Inactivation of EGFR inhibits the anchorage independence and AKT pathway promoted by ITGB4. Further investigation proved that the ITGB4-EGFR unit triggers the focal adhesion kinase (FAK) to activate the AKT signaling pathway. Finally, we demonstrate that over-expression of ITGB4 is positively associated with tumor growth and lung metastases of HCC in vivo. Collectively, we demonstrate for the first time that ITGB4 is overexpressed in HCC tissues and promotes metastases of HCC by conferring anchorage independence through EGFR-dependent FAK-AKT activation.

MicroRNA-130b promotes proliferation and EMT-induced metastasis via PTEN/p-AKT/HIF-1α signaling

Hepatocellular carcinoma (HCC) is a major cause of cancer-related deaths owing to its high rate of postoperative recurrence and metastasis. New research is continuously identifying novel metastasis-associated oncogenes and tumor suppressor genes. miRNAs are noncoding RNAs that regulate protein synthesis post-translationally. miR-130b is one of several miRNAs involved in tumor metastasis. However, the role of miR-130b in HCC remains controversial. Here, we demonstrate that miR-130b is highly expressed in HCC and that it correlates with tumor number, vascular invasion, and TNM stage-important predictors of postoperative recurrence and metastases. Moreover, high levels of miR-130b predicted poor overall and disease-free survival of HCC patients, and in vitro and in vivo research revealed that knockdown or overexpression of miR-130b inhibited and promoted proliferation and metastasis of HCC cells, respectively. We identified PTEN as a direct functional target of miR-130b using miRNA databases and a dual luciferase report assay. Next, using a gain and loss assay and epithelial-mesenchymal transition (EMT) relative assays, we show that miR-130b may promote proliferation and EMT-induced metastasis via PTEN/p-AKT/HIF-1α signaling. Collectively, our data suggests that miR-130b may have prognostic value in HCC. Additionally, the miR-130b/PTEN/p-AKT/HIF-1α axis identified in this study provides novel insight into the mechanisms of HCC metastasis, which may facilitate the development of new therapeutics against HCC.

Generation and characterization of a tetraspanin CD151/integrin α6β1-binding domain competitively binding monoclonal antibody for inhibition of tumor progression in HCC

Our previous studies revealed that tetraspanin CD151 plays multiple roles in the progression of hepatocellular carcinoma (HCC) by forming a functional complex with integrin α6β1. Herein, we generated a monoclonal antibody (mAb) that dissociates the CD151/integrin α6β1 complex, and we evaluated its bioactivity in HCCs. A murine mAb, tetraspanin CD151 (IgG1, called CD151 mAb 9B), was successfully generated against the CD151-integrin α6β1 binding site of CD151 extracellular domains. Co-immunoprecipitation using CD151 mAb 9B followed by Western blotting detected a 28 kDa protein. Both immunofluorescent and immunohistochemical staining showed a good reactivity of CD151 mAb 9B in the plasma membrane and cytoplasm of HCC cells, as well as in liver cells. In vitro assays demonstrated that CD151 mAb 9B could inhibit neoangiogenesis and both the mobility and the invasiveness of HCC cells. An in vivo assay showed that CD151 mAb 9B inhibited tumor growth potential and HCC cells metastasis. We successfully produced a CD151 mAb 9B targeting the CD151/integrin α6β1-binding domain, which not only can displayed good reactivity to the CD151 antigen but also prevented tumor progression in HCC.