5'-Ectonucleotidase CD73/NT5E supports EGFR-mediated invasion of HPV-negative head and neck carcinoma cells.

BACKGROUND: Epithelial-to-mesenchymal transition (EMT) of malignant cells is a driving force of disease progression in human papillomavirus-negative (HPV-negative) head and neck squamous cell carcinomas (HNSCC). Sustained hyper-activation of epidermal growth factor receptor (EGFR) induces an invasion-promoting subtype of EMT (EGFR-EMT) characterized by a gene signature ("'EGFR-EMT_Signature'") comprising 5´-ectonucleotidase CD73. Generally, CD73 promotes immune evasion via adenosine (ADO) formation and associates with EMT and metastases. However, CD73 regulation through EGFR signaling remains under-explored and targeting options are amiss. METHODS: CD73 functions in EGFR-mediated tumor cell dissemination were addressed in 2D and 3D cellular models of migration and invasion. The novel antagonizing antibody 22E6 and therapeutic antibody Cetuximab served as inhibitors of CD73 and EGFR, respectively, in combinatorial treatment. Specificity for CD73 and its role as effector or regulator of EGFR-EMT were assessed upon CD73 knock-down and over-expression. CD73 correlation to tumor budding was studied in an in-house primary HNSCC cohort. Expression correlations, and prognostic and predictive values were analyzed using machine learning-based algorithms and Kaplan-Meier survival curves in single cell and bulk RNA sequencing datasets. RESULTS: CD73/NT5E is induced by the EGF/EGFR-EMT-axis and blocked by Cetuximab and MEK inhibitor. Inhibition of CD73 with the novel antagonizing antibody 22E6 specifically repressed EGFR-dependent migration and invasion of HNSCC cells in 2D. Cetuximab and 22E6 alone reduced local invasion in a 3D-model. Interestingly, combining inefficient low-dose concentrations of Cetuximab and 22E6 revealed highly potent in invasion inhibition, substantially reducing the functional IC50 of Cetuximab regarding local invasion. A role for CD73 as an effector of EGFR-EMT in local invasion was further supported by knock-down and over-expression experiments in vitro and by high expression in malignant cells budding from primary tumors. CD73 expression correlated with EGFR pathway activity, EMT, and partial EMT (p-EMT) in malignant single HNSCC cells and in large patient cohorts. Contrary to published data, CD73 was not a prognostic marker of overall survival (OS) in the TCGA-HNSCC cohort when patients were stratified for HPV-status. However, CD73 prognosticated OS of oral cavity carcinomas. Furthermore, CD73 expression levels correlated with response to Cetuximab in HPV-negative advanced, metastasized HNSCC patients. CONCLUSIONS: In sum, CD73 is an effector of EGF/EGFR-mediated local invasion and a potential therapeutic target and candidate predictive marker for advanced HPV-negative HNSCC.

A transcriptomic map of EGFR-induced epithelial-to-mesenchymal transition identifies prognostic and therapeutic targets for head and neck cancer.

BACKGROUND: Epidermal growth factor receptor (EGFR) is both a driver oncogene and a therapeutic target in advanced head and neck squamous cell carcinoma (HNSCC). However, response to EGFR treatment is inconsistent and lacks markers for treatment prediction. This study investigated EGFR-induced epithelial-to-mesenchymal transition (EMT) as a central parameter in tumor progression and identified novel prognostic and therapeutic targets, and a candidate predictive marker for EGFR therapy response. METHODS: Transcriptomic profiles were analyzed by RNA sequencing (RNA-seq) following EGFR-mediated EMT in responsive human HNSCC cell lines. Exclusive genes were extracted via differentially expressed genes (DEGs) and a risk score was determined through forward feature selection and Cox regression models in HNSCC cohorts. Functional characterization of selected prognostic genes was conducted in 2D and 3D cellular models, and findings were validated by immunohistochemistry in primary HNSCC. RESULTS: An EGFR-mediated EMT gene signature composed of n = 171 genes was identified in responsive cell lines and transferred to the TCGA-HNSCC cohort. A 5-gene risk score comprising DDIT4, FADD, ITGB4, NCEH1, and TIMP1 prognosticated overall survival (OS) in TCGA and was confirmed in independent HNSCC cohorts. The EGFR-mediated EMT signature was distinct from EMT hallmark and partial EMT (pEMT) meta-programs with a differing enrichment pattern in single malignant cells. Molecular characterization showed that ITGB4 was upregulated in primary tumors and metastases compared to normal mucosa and correlated with EGFR/MAPK activity in tumor bulk and single malignant cells. Preferential localization of ITGB4 together with its ligand laminin 5 at tumor-stroma interfaces correlated with increased tumor budding in primary HNSCC tissue sections. In vitro, ITGB4 knock-down reduced EGFR-mediated migration and invasion and ITGB4-antagonizing antibody ASC8 impaired 2D and 3D invasion. Furthermore, a logistic regression model defined ITGB4 as a predictive marker of progression-free survival in response to Cetuximab in recurrent metastatic HNSCC patients. CONCLUSIONS: EGFR-mediated EMT conveyed through MAPK activation contributes to HNSCC progression upon induction of migration and invasion. A 5-gene risk score based on a novel EGFR-mediated EMT signature prognosticated survival of HNSCC patients and determined ITGB4 as potential therapeutic and predictive target in patients with strong EGFR-mediated EMT.

Transcriptome-based network analysis related to M2-like tumor-associated macrophage infiltration identified VARS1 as a potential target for improving melanoma immunotherapy efficacy.

RATIONALE: The M2-like tumor-associated macrophages (TAMs) are independent prognostic factors in melanoma. METHODS: We performed weighted gene co-expression network analysis (WGCNA) to identify the module most correlated with M2-like TAMs. The Cancer Genome Atlas (TCGA) patients were classified into two clusters that differed based on prognosis and biological function, with consensus clustering. A prognostic model was established based on the differentially expressed genes (DEGs) of the two clusters. We investigated the difference in immune cell infiltration and immune response-related gene expression between the high and low risk score groups. RESULTS: The risk score was defined as an independent prognostic value in melanoma. VARS1 was a hub gene in the M2-like macrophage-associated WGCNA module that the DepMap portal demonstrated was necessary for melanoma growth. Overexpressing VARS1 in vitro increased melanoma cell migration and invasion, while downregulating VARS1 had the opposite result. VARS1 overexpression promoted M2 macrophage polarization and increased TGF-ß1 concentrations in tumor cell supernatant in vitro. VARS1 expression was inversely correlated with immune-related signaling pathways and the expression of several immune checkpoint genes. In addition, the VARS1 expression level helped predict the response to anti-PD-1 immunotherapy. Pan-cancer analysis demonstrated that VARS1 expression negatively correlated with CD8 T cell infiltration and the immune response-related pathways in most cancers. CONCLUSION: We established an M2-like TAM-related prognostic model for melanoma and explored the role of VARS1 in melanoma progression, M2 macrophage polarization, and the development of immunotherapy resistance.

Local Riluzole Release from a Thermosensitive Hydrogel Rescues Injured Motoneurons through Nerve Root Stumps in a Brachial Plexus Injury Rat Model.

The C5-C6 nerve roots are usually spared from avulsion after brachial plexus injury (BPI) and can thus be used as donors for nerve repair. A BPI rat model with C5-C6 nerve root stumps has been established in our previous work. The aim of this study was to test whether riluzole loaded into a thermosensitive hydrogel could applied locally in the nerve root stumps of this BPI rat model, thus increasing the reparative effect of the nerve root stumps. Nile red (a hydrophobic dye) was used as a substitute for riluzole since riluzole itself does not emit light. Nile red, loaded into a thermosensitive hydrogel, was added to the nerve root stumps of the BPI rat model. Additionally, eighteen rats, with operation on right brachial plexus, were evenly divided into three groups: control (Con), thermosensitive hydrogel (Gel) and thermosensitive hydrogel loaded with riluzole (Gel + Ri) groups. Direct nerve repair was performed after local riluzole release for two weeks. Functional and electrophysiological evaluations and histological assessments were used to evaluate the reparative effect 8 weeks after nerve repair. Nile red was slowly released from the thermosensitive hydrogel and retrograde transport through the nerve root stumps to the motoneurons, according to immunofluorescence. Discernible functional recovery began earlier in the Gel + Ri group. The compound muscle action potential, ChAT-expressing motoneurons, positivity for neurofilaments and S100, diameter of regenerating axons, myelin sheath thickness and density of myelinated fibers were markedly increased in the Gel + Ri group compared with the Con and Gel groups. Our results indicate that the local administration of riluzole could undergo retrograde transportation through C5-C6 nerve root stumps, thereby promoting neuroprotection and increasing nerve regeneration.

Establishing a Prognostic Model Based on Ulceration and Immune Related Genes in Melanoma Patients and Identification of EIF3B as a Therapeutic Target.

Ulceration and immune status are independent prognostic factors for survival in melanoma patients. Herein univariate Cox regression analysis revealed 53 ulcer-immunity-related DEGs. We performed consensus clustering to divide The Cancer Genome Atlas (TCGA) cohort (n = 467) into three subtypes with different prognosis and biological functions, followed by validation in three merged Gene Expression Omnibus (GEO) cohorts (n = 399). Multiomics approach was used to assess differences among the subtypes. Cluster 3 showed relatively lesser amplification and expression of immune checkpoint genes. Moreover, Cluster 3 lacked immune-related pathways and immune cell infiltration, and had higher proportion of non-responders to immunotherapy. We also constructed a prognostic model based on ulceration and immune related genes in melanoma. EIF3B was a hub gene in the intersection between genes specific to Cluster 3 and those pivotal for melanoma growth (DepMap, https://depmap.org/portal/download/). High EIF3B expression in TCGA and GEO datasets was related to worst prognosis. In vitro models revealed that EIF3B knockdown inhibited melanoma cell migration and invasion, and decreased TGF-ß1 level in supernatant compared with si-NC cells. EIF3B expression was negatively correlated with immune-related signaling pathways, immune cell gene signatures, and immune checkpoint gene expression. Moreover, its low expression could predict partial response to anti-PD-1 immunotherapy. To summarize, we established a prognostic model for melanoma and identified the role of EIF3B in melanoma progression and immunotherapy resistance development.

SLUG-related partial epithelial-to-mesenchymal transition is a transcriptomic prognosticator of head and neck cancer survival.

Partial epithelial-to-mesenchymal transition (pEMT) contributes to cellular heterogeneity that is associated with nodal metastases and unfavorable clinical parameters in head and neck squamous cell carcinomas (HNSCCs). We developed a single-cell RNA sequencing signature-based pEMT quantification through cell type-dependent deconvolution of bulk RNA sequencing and microarray data combined with single-sample scoring of molecular phenotypes (Singscoring). Clinical pEMT-Singscores served as molecular classifiers in multivariable Cox proportional hazard models and high scores prognosticated poor overall survival and reduced response to irradiation as independent parameters in large HNSCC cohorts [The Cancer Genome Atlas (TCGA), MD Anderson Cancer Centre (MDACC), Fred Hutchinson Cancer Research Center (FHCRC)]. Differentially expressed genes confirmed enhanced cell motility and reduced oxidative phosphorylation and epithelial differentiation in pEMThigh patients. In patients and cell lines, the EMT transcription factor SLUG correlated most strongly with pEMT-Singscores and promoted pEMT, enhanced invasion, and resistance to irradiation in vitro. SLUG protein levels in HNSCC predicted disease-free survival, and its peripheral expression at the interphase to the tumor microenvironment was significantly increased in relapsing patients. Hence, pEMT-Singscores represent a novel risk predictor for HNSCC stratification regarding clinical outcome and therapy response that is partly controlled by SLUG.

A novel rat model of tibial fracture for trauma researches: a combination of different types of fractures and soft tissue injuries.

BACKGROUND: The outcomes for open tibial fractures with severe soft tissue injury are still a great challenge for all the trauma surgeons in the treatment. However, most of the existing open tibial fracture models can only provide minimal soft tissue injury which cannot meet the requirement of severe trauma research. Our goal is to investigate a novel tibial fracture model providing different fractures combined with soft tissue injury for better application in trauma research. METHODS: A total of 144 Sprague-Dawley rats were randomly divided into 4 groups. With group 1 as control, the other groups sustained different right tibial fractures by the apparatus with buffer disc settings either 3 mm, 10 mm, or 15 mm. X-ray and computed tomography angiography (CTA) were performed at 6 h to evaluate the fracture patterns and vascular injuries. Peripheral blood and tibialis anterior muscle were harvested at 6 h, 1 day, 3 days, 7 days, 14 days, and 28 days for ELISA and histological analysis. RESULTS: X-ray and µCT results indicated that different fractures combined with soft tissue injuries could be successfully provided in this model. According to OTA and Gustilo classification, the fractures and soft tissue injuries were evaluated and defined: 36 type I in group 2, 34 type II in group 3, and 36 type III in group 4. The CTA confirmed no arterial injuries in groups 1 and 2, 2 arterial injuries in group 3, and 35 in group 4. ELISA indicated that the levels of pro-inflammatory cytokines TNF-α and IL-1ß were significantly higher in group 4 than in other groups, and the levels of anti-inflammatory cytokines TGF-ß and IL-10 were significantly higher in surgery groups than in group 1 in later stage or throughout the entire process. HE, Masson, and caspase-3 stains confirmed the most severe inflammatory cell infiltration and apoptosis in group 4 which lasted longer than that in groups 2 and 3. CONCLUSIONS: The novel apparatus was valuable in performing different fractures combined with soft tissue injuries in a rat tibial fracture model with high reproducibility and providing a new selection for trauma research in the future.

Inhibitory effect of melittin on endonuclease-like activity of centrin.

The xeroderma pigmentosum group C protein (XPC) and centrin2 are the primary initiators of global genome nucleotide excision repair (NER). Centrin, acts as a member of the EF-hand super family of calcium-binding proteins, playing roles in reconstitution of the vitro NER reaction. To understand the possible molecular and structural properties of the multiprotein process, the interactions of Euplotes octocarinatus centrin (EoCen), melittin, and DNA are described. EoCen shares a sequence identity of 66% with centrin2. Melittin possesses inverse direction hydrophobic triads-leucine-leucine-tryptophan (LLW) which are responsible for centrin binding. It is applied as a natural peptide to mimic centrin target peptide. As a result, it is proved that the integrated protein shows an endonuclease-like activity to DNA. Melittin is capable of interaction with both EoCen and DNA. More importantly, it is found that melittin displays an inhibitory effect on the endonuclease-like activity of centrin when it co-exists with EoCen and DNA in solution. Meanwhile, the DNA-melittin-EoCen ternary complex forms in the process. Quantitative analyses demonstrated by extensive biophysical assays reveal that binding of the peptide to DNA or centrin modulates the binding properties of it to another component. Furthermore, a possible positioning model of DNA and EoCen on melittin is proposed. This finding may constitute a model for that existing between centrin and its target peptide in NER process.

Modulation effect of double strand DNA on the self-assembly of N-terminal domain of Euplotes octocarinatus centrin.

Centrin is a member of the EF-hand super family of calcium-binding proteins, which can behave as a part of damage detector initiated the initiation of nucleotide excision repair (NER). Its self-assembly plays a causative role in fiber contraction associated with the cell division cycle and ciliogenesis. To explore the possible role of DNA in the process of centrin self-assembly, the aggregation properties of N-terminal domain of Euplotes octocarinatus centrin (N-EoCen) in the presence of DNA with or without metal ions are investigated. It is verified that metal ions, such as Ca2+ and Tb3+, can bind to N-EoCen with 2:1 stoichiometry by isothermal titration calorimetry (ITC). Importantly, this study reports that double strand DNA (dsDNA) is capable of binding N-EoCen, changing conformation of protein and modulating centrin aggregation, as demonstrated by extensive biophysical assays. Interestingly, the open conformation of protein induced by metal ions may be favour of the interaction of protein with dsDNA. Nevertheless, the randomly coiled single strand DNA (ssDNA) is completely inefficient to the aggregation regulation. Furthermore, results reveal that hydrophobic site could play important role in the process. This finding may link to the potent roles of centrin in the NER process.

Modulation of XPC peptide on binding Tb3+ to Euplotes octocarinatus centrin.

Centrins are Ca2+-binding proteins found throughout eukaryotic organisms. Xeroderma pigmentosum group C protein (XPC), a dominant component of the nuclear excision repair (NER) pathway, is a critical target protein of centrins. A 22-residue peptide (K842-R863) from XPC was used to investigate the effect of metal ions (Ca2+ and Tb3+) on the peptide binding of Euplotes octocarinatus centrin (EoCen) by isothermal titration calorimetry (ITC) and fluorescence spectroscopy. ITC and tryptophan spectrofluorimetric titrations revealed that metal ions (Ca2+ and Tb3+) could enhance the affinity between EoCen and the XPC peptide, and the enhanced effects were closely related to the ion potential of metal ions. Since the ion potential of Tb3+ (e/r = 0.0325) is larger than that of Ca2+ (e/r = 0.0202), the conformational change in the protein induced by Tb3+ is larger than that induced by Ca2+, and the enhanced affinity of Tb3+ is stronger than that of Ca2+. This interaction was driven by enthalpy in the presence of EDTA and enthalpy and entropy in the presence of Ca2+ or Tb3+. Similar to that observed in the presence of EDTA, the N-terminal domain did not participate in the interaction with the XPC peptide even in the presence of metal ions. Resonance light scattering (RLS) and the band shift in native polyacrylamide gel electrophoresis (PAGE) suggested that peptide binding resulted in the dissociation of EoCen aggregates and complex formation via the monomer-peptide form. Tb3+-Sensitized emission suggested that peptide binding in turn also had an impact on the Tb3+ binding of the protein: the C-terminal domain was slightly strengthened and the N-terminal domain was weakened about 225 fold. RLS and native PAGE indicated that the self-assembly induced by Tb3+ binding to the N-terminal domain of EoCen was inhibited in the presence of the XPC peptide. This study elucidates the molecular mechanism of EoCen function in the cellular context.

Polyaryl ether dendrimer with a 4-phenylacetyl-5-pyrazolone-based terbium(III) complex as core: synthesis and photophysical properties.

A series of novel dendritic beta-diketone ligands, 1-phenyl-3-[G-n]-4-phenylacetyl-5-pyrazolone (n = 0-3, G stands for polyaryl ether), were synthesized by introducing Fréchet-type dendritic branches. The corresponding Tb3+-cored dendritic complexes were characterized by X-ray crystallography, elemental analysis, ESI mass spectra, and FT-IR spectra. These dendritic complexes, prepared from aqueous solution, exhibit high stability. Interestingly, the study of photophysical properties shows that the luminescence quantum yields of the dendritic Tb-complexes increase from 0.1 to 2.26% with an increase of the dendritic generation from 0 to 3. Importantly, an "energy-reservoir effect" was observed in the dendritic system using the method based on the resonance energy transfer from these complexes to rhodamine 6G. With the increase of the dendritic generation, the metal-centered luminescence quantum yield was almost the same, and the energy transfer (phi(transfer)) from the ligand to Tb(3+) increased. Further measurements of the triplet state and oxygen quenching of these dendritic complexes verify that this enhancement of the energy transfer (phi(transfer)) is attributed to both an "antenna effect" and a "shell effect".