Ang1/Tie2 induces cell proliferation and migration in human papillary thyroid carcinoma via the PI3K/AKT pathway

Neuroprotective effects of a novel peptide through the Rho-integrin-Tie2 and PI3K/Akt pathways in experimental autoimmune encephalomyelitis model

Purpose: The interaction between inflammatory cells and integrin in the endothelium plays a key role during infiltration. Previous evidence has shown that synthetic C16 peptide selectively binds to integrins αvβ3 and α5β1 and exhibits a neuroprotective effect. It has also been reported to inhibit the differentiation of microglia into the M1 (pro-inflammatory) phenotype while promoting its differentiation to the M2 (anti-inflammatory) phenotype. This study aimed to investigate the mechanisms of action of the C16 peptide in multiple sclerosis using a rodent model. Methods: Molecular, morphological, and neurophysiological assays were used to investigate the neuroprotective effects of C16 peptide and related signaling pathways in a model of EAE. Results: The results showed that C16 significantly improved the clinical score and cortical somatosensory/motor evoked potential. It also alleviated inflammatory responses, including microglial activation and leukocyte infiltration, relieved the impairment of the brain blood barrier and edema, and reduced neuronal apoptosis, axonal loss, and demyelination induced by EAE. The C16 peptide increased the expressions of pTie-2 and Tie-2, integrin αvβ3, and α5β1 and activated the PI3K/Akt signal pathway but decreased the expression of Rho. Co-treatment of C16 with Tie-2 inhibitor and PI3K inhibitor LY294002 attenuated these effects of C16. Conclusion: The C16 peptide demonstrated neuroprotection in the EAE model through the integrin, Tie-2, and PI3K/Akt signaling pathways, and it could be a potential strategy for treating inflammation-related diseases in the central nervous system.

The Emerging Role of Pericyte-Derived Extracellular Vesicles in Vascular and Neurological Health

Pericytes (PCs), as a central component of the neurovascular unit, contribute to the regenerative potential of the central nervous system (CNS) and peripheral nervous system (PNS) by virtue of their role in blood flow regulation, angiogenesis, maintenance of the BBB, neurogenesis, and neuroprotection. Emerging evidence indicates that PCs also have a role in mediating cell-to-cell communication through the secretion of extracellular vesicles (EVs). Extracellular vesicles are cell-derived, micro- to nano-sized vesicles that transport cell constituents such as proteins, nucleic acids, and lipids from a parent originating cell to a recipient cell. PC-derived EVs (PC-EVs) play a crucial homeostatic role in neurovascular disease, as they promote angiogenesis, maintain the integrity of the blood-tissue barrier, and provide neuroprotection. The cargo carried by PC-EVs includes growth factors such as endothelial growth factor (VEGF), connecting tissue growth factors (CTGFs), fibroblast growth factors, angiopoietin 1, and neurotrophic growth factors such as brain-derived neurotrophic growth factor (BDNF), neuron growth factor (NGF), and glial-derived neurotrophic factor (GDNF), as well as cytokines such as interleukin (IL)-6, IL-8, IL-10, and MCP-1. The PC-EVs also carry miRNA and circular RNA linked to neurovascular health and the progression of several vascular and neuronal diseases. Therapeutic strategies employing PC-EVs have potential in the treatment of vascular and neurodegenerative diseases. This review discusses current research on the characteristic features of EVs secreted by PCs and their role in neuronal and vascular health and disease.

Angiopoietin-1 Upregulates Cancer Cell Motility in Colorectal Cancer Liver Metastases through Actin-Related Protein 2/3

Resistance to anti-angiogenic therapy is a major challenge in the treatment of colorectal cancer liver metastases (CRCLMs). Vessel co-option has been identified as a key contributor to anti-angiogenic therapy resistance in CRCLMs. Recently, we identified a positive correlation between the expression of Angiopoietin1 (Ang1) in the liver and the development of vessel co-opting CRCLM lesions in vivo. However, the mechanisms underlying its stimulation of vessel co-option are unclear. Herein, we demonstrated Ang1 as a positive regulator of actin-related protein 2/3 (ARP2/3) expression in cancer cells, in vitro and in vivo, which is known to be essential for the formation of vessel co-option in CRCLM. Significantly, Ang1-dependent ARP2/3 expression was impaired in the cancer cells upon Tie2 or PI3K/AKT inhibition in vitro. Taken together, our results suggest novel mechanisms by which Ang1 confers the development of vessel co-option in CRCLM, which, targeting this pathway, may serve as promising therapeutic targets to overcome the development of vessel co-option in CRCLM.

SIRT7 interacts with TEK (TIE2) to promote adriamycin induced metastasis in breast cancer

PURPOSE

Emerging evidence suggests that cytotoxic therapy may promote drug resistance and metastasis while inhibiting the growth of primary tumors. As yet, however, the underlying mechanisms remain unclear. Here, we aimed to investigate the pro-metastatic effects of adriamycin (ADR) therapy on breast cancer cells and to investigate the mechanisms underlying these effects.

METHODS

Differentially expressed genes between MCF-7 and ADR-resistant MCF-7 breast cancer cells were identified using high-throughput RNA-seq and differential gene expression analyses. In vitro transwell and scratch wound-healing assays, and an in vivo spontaneous metastasis model were used to study the metastatic potential of the breast cancer cells. The relationship between SIRT7 and TEK expression was studied using promoter activity, electrophoretic mobility shift (EMSA), CHIP-qPCR and Co-IP assays.

RESULTS

Using transcriptome sequencing, we identified two key genes (SIRT7 and TEK) that might contribute to the pro-metastatic effect of ADR on breast cancer cells. SIRT7 acted as a negative regulator for TEK by inducing deacetylation of H3K18 at the TEK promoter. Through transcription factor prediction and double fluorescence experiments, we found that EST-1 could bind to the TEK promoter. Knockdown of EST-1 removed the transcriptional inhibition of TEK that was mediated by up-regulation of SIRT7. Co-IP showed that SIRT7 interacts directly with EST-1 in breast cancer cells, indicating that SIRT7 may induce H3K18 deacetylation at the TEK promoter region by directly binding to EST-1. In vitro and in vivo results showed that overexpression of SIRT7 or inhibition of TIE2 significantly reduced ADR-dependent breast cancer cell invasion/metastasis.

CONCLUSION

Our findings suggest that ADR therapy may accelerate breast cancer metastasis in a SIRT7/TEK(TIE2) dependent manner.

Silencing of Long Non-coding RNA ENST00000606790.1 Inhibits the Malignant Behaviors of Papillary Thyroid Carcinoma through the PI3K/AKT Pathway

PURPOSE

This study aimed to investigate the role and mechanism of lncRNA ENST00000606790.1 (ENST) in promoting the progression of papillary thyroid carcinoma (PTC).

METHODS

The expression of ENST in human PTC and normal para-cancerous thyroid (NPTC) tissues or cell lines was determined by RT-qPCR. Cell growth was determined by CCK8 assay. Cell colony formation was determined by cell colony formation assay. Cell cycle analysis was performed by staining cells with PI (Propidium Iodide). Cell invasion was assessed by transwell assay. Protein expression was examined by western-blot. siRNA was constructed to inhibit the expression of ENST. 740-Y-P was used to activate PI3K. The correlation between ENST expression and clinical outcomes was analyzed.

RESULTS

ENST was significantly up-regulated in PTC tissues or PTC cell lines (PTC and IHH4 cell lines), compared to NPTC tissues or normal cell lines, respectively. High expression of ENST was strongly correlated to lymph node metastasis and tumor size at diagnosis. Silencing of ENST significantly inhibited cell growth and colony formation, arrested the cell cycle at G2/M phase, upregulated the expression of CHK1, downregulated the expression of CDC25C, and inhibited cell invasion. Silencing of ENST significantly down-regulated the expression of PI3K, p-PI3K, AKT, and p-AKT in IHH4 cells. Furthermore, treatment with the PI3K activator  740-Y-P partially abolished the effect of silencing of ENST on PTC cells.

CONCLUSIONS

Overall, our results demonstrated that ENST can promote PTC progression by activating the PI3K/AKT signaling pathway, suggesting that ENST can serve as a potential biomarker and new therapeutic target for patients with PTC.

Tek (Tie2) is not required for cardiovascular development in zebrafish

Angiopoietin/TIE signalling plays a major role in blood and lymphatic vessel development. In mouse, Tek (previously known as Tie2) mutants die prenatally due to a severely underdeveloped cardiovascular system. In contrast, in zebrafish, previous studies have reported that although embryos injected with tek morpholinos (MOs) exhibit severe vascular defects, tek mutants display no obvious vascular malformations. To further investigate the function of zebrafish Tek, we generated a panel of loss-of-function tek mutants, including RNA-less alleles, an allele lacking the MO-binding site, an in-frame deletion allele and a premature termination codon-containing allele. Our data show that all these mutants survive to adulthood with no obvious cardiovascular defects. MO injections into tek mutants lacking the MO-binding site or the entire tek locus cause similar vascular defects to those observed in MO-injected +/+ siblings, indicating off-target effects of the MOs. Surprisingly, comprehensive phylogenetic profiling and synteny analyses reveal that Tek was lost in the largest teleost clade, suggesting a lineage-specific shift in the function of TEK during vertebrate evolution. Altogether, these data show that Tek is dispensable for zebrafish development, and probably dispensable in most teleost species.

Angiopoietin-1 is associated with a decreased risk of lymph node metastasis in early stage cervical cancer

OBJECTIVES

Lymph node metastasis (LNM) is an important determinant of prognosis in patients with cervical cancer. Members of the angiopoietin family have been demonstrated to regulate tumor-associated angiogenesis and lymphangiogenesis. This study aimed to investigate the expression levels of angiopoietin-1 (ANG1) and angiopoietin-2 (ANG2) in clinically early stage of cervical cancer along with their correlations with LNM.

METHODS

In total, 124 human cervical cancer cases classified into stage IA-IIB in accordance with the International Federation of Gynecology and Obstetrics (FIGO) 2009 staging criteria were included. ANG1 and ANG2 expression levels in the tumor sections were assessed by immunohistochemistry (IHC). Univariate and multivariate logistic regression models, including age at diagnosis, FIGO stage, tumor size, pathological type, histological grading, depth of stromal invasion, lymph-vascular space invasion (LVSI) and the expression status of ANG1 and ANG2, were used to evaluate the odds ratios (ORs) for LNM.

RESULTS

ANG1 and ANG2 were positively expressed in 75 (60.5%) and 89 (71.8%) cervical cancers respectively, with predominant staining in the cytoplasm. ANG1 expression was significantly decreased in tumors with LNM, while no correlation was observed between ANG2 expression and LNM. More importantly, the multivariate logistic regression analysis demonstrated that high ANG1 expression was an independent protective factor of LNM (OR 0.107, 95% confidential interval [CI] 0.020~0.567), while LVSI was an independent risk factor of LNM (OR 34.313, 95% CI 5.914~199.092).

CONCLUSION

ANG1 is associated with a significantly decreased risk of LNM in early stage cervical cancer. The predictive value and role of ANG1 in LNM needs to be further investigated in future studies.

Angiopoietin1 Deficiency in Hepatocytes Affects the Growth of Colorectal Cancer Liver Metastases (CRCLM)

Colorectal cancer liver metastases (CRCLM) that receive their blood supply via vessel co-option are associated with a poor response to anti-angiogenic therapy. Angiopoietins (Ang1 and Ang2) with their Tyrosine-protein kinase receptor (Tie2) have been shown to support vessel co-option. We demonstrate significantly higher expression of Ang1 in hepatocytes adjacent to the tumor region of human chemonaïve and treated co-opting (replacement histopathological growth patterns: RHGP) tumors. To investigate the role of the host Ang1 expression, Ang1 knockout (KO) mice were injected intra-splenically with metastatic MC-38 colon cancer cells that develop co-opting liver metastases. We observed a reduction in the number of liver metastases and interestingly, for the first time, the development of angiogenic driven desmoplastic (DHGP) liver metastases. In addition, in-vitro, knockout of Ang1 in primary hepatocytes inhibited viability, migration and invasion ability of MC-38 cells. We also demonstrate that Ang 1 alone promotes the migration and growth of both human and mouse colon cancer cell lines These results provide evidence that high expression of Ang1 in the host liver is important to support vessel co-option (RHGP lesions) and when inhibited, favours the formation of angiogenic driven liver metastases (DHGP lesions).

Identification of Altered Circular RNA Expression in Serum Exosomes from Patients with Papillary Thyroid Carcinoma by High-Throughput Sequencing

Background

This study aimed to identify altered exosome circular RNA (circRNA) in the serum of patients with papillary thyroid carcinoma using high-throughput sequencing.

Material/Methods

Serum was collected from three patients with papillary thyroid carcinoma and three patients with a benign thyroid goiter. Exosomes were isolated using an exosome isolation kit and confirmed by transmission electron microscopy. Exosome circRNAs were analyzed by high-throughput sequencing using the HiSeq 4000 sequencer. The differentially expressed circRNAs were confirmed by fluorescence quantitative real-time polymerase chain reaction (qRT-PCR).

Results

Twenty-two differentially expressed circRNAs were screened, which included three that were upregulated and 19 that were down-regulated in serum from patients with papillary thyroid carcinoma compared with controls. Gene Ontology (GO) enrichment analysis showed that these differentially expressed circRNAs were associated with 16 signaling pathways, including the thyroid hormone signaling pathway, the PI3K-Akt signaling pathway, and the AMPK signaling pathway. Three differentially regulated circRNAs included hsacirc_007293, hsacirc_031752, and hsacirc_020135 were confirmed by qRT-PCR. The expression trends were consistent between the high-throughput sequencing technique and qRT-PCR.

Conclusions

The findings from this study have shown that gene regulation can be studied from exosomes obtained from serum samples in patients with papillary thyroid carcinoma, and supports the need for further studies on the role of exosome circRNAs in thyroid cancer.

Prediction of novel target genes and pathways involved in tall cell variant papillary thyroid carcinoma

BACKGROUND

Tall cell variant papillary thyroid carcinoma (TCPTC) is reportedly associated with aggressive clinicopathological parameters and poor outcomes; however, the molecular mechanisms underlying TCPTC remain poorly understood.

METHODS

The gene mutation types and mRNA expression profiles of patients with TCPTC were obtained from The Cancer Genome Atlas (TCGA) database. Differentially expressed genes (DEGs) were identified. Pathways in the interaction network and the diagnostic approaches of candidate markers for TCPTC were investigated.

RESULTS

BRAF mutation was particularly prevalent in TCPTC with a mutation frequency of 78%. TCPTC was associated with a patient age >45 years, tumor multifocality, extrathyroidal extension, a higher T stage, advanced AJCC TNM stages, BRAF V600E mutation, and poor disease-free survival. We identified 4138 TCPTC-related DEGs and 301 TCPTC-specific DEGs. Intriguingly, the gene expression pattern revealed that the dysregulated levels of both putative oncogenes and tumor suppressors in TCPTC were higher than those in classical/conventional variant PTC (cPTC). Functional enrichment analyses revealed that these DEGs were involved in several cancer-related pathways. A protein-protein interaction (PPI) network was constructed from the 301 TCPTC-specific DEGs, and 3 subnetworks, and 8 hub genes were verified. Receiver operating characteristic (ROC) analyses revealed that 6 hub genes, including COL5A1, COL1A1, COL10A1, COL11A1, CCL20, and CXCL5, could be used not only for the differential diagnosis of PTC from normal samples, but also for the differential diagnosis of TCPTC from cPTC samples.

CONCLUSIONS

Our study might provide further insights into the investigations of the tumorigenesis mechanism of TCPTC and assists in the discovery of novel candidate diagnostic markers for TCPTC.

Phosphorylation of serine/arginine-rich splicing factor 1 at tyrosine 19 promotes cell proliferation in pediatric acute lymphoblastic leukemia

Serine/arginine‐rich splicing factor 1 (SRSF1) has been linked to various human cancers including pediatric acute lymphoblastic leukemia (ALL). Our previous study has shown that SRSF1 potentially contributes to leukemogenesis; however, its underlying mechanism remains unclear. In this study, leukemic cells were isolated from pediatric ALL bone marrow samples, followed by immunoprecipitation assays and mass spectrometry analysis specific to SRSF1. Subcellular localization of the SRSF1 protein and its mutants were analyzed by immunofluorescence staining. Cell growth, colony formation, cell apoptosis, and the cell cycle were investigated using stable leukemic cell lines generated with lentivirus‐mediated overexpressed WT or mutant plasmids. Cytotoxicity of the Tie2 kinase inhibitor was also evaluated. Our results showed the phosphorylation of SRSF1 at tyrosine 19 (Tyr‐19) was identified in newly diagnosed ALL samples, but not in complete remission or normal control samples. Compared to the SRSF1 WT cells, the missense mutants of the Tyr‐19 phosphorylation affected the subcellular localization of SRSF1. In addition, the Tyr‐19 phosphorylation of SRSF1 also led to increased cell proliferation and enhanced colony‐forming properties by promoting the cell cycle. Remarkably, we further identified the kinase Tie2 as a potential therapeutic target in leukemia cells. In conclusion, we identify for the first time that the phosphorylation state of SRSF1 is linked to different phases in pediatric ALL. The Tyr‐19 phosphorylation of SRSF1 disrupts its subcellular localization and promotes proliferation in leukemia cells by driving cell‐cycle progression. Inhibitors targeting Tie2 kinase that could catalyze Tyr‐19 phosphorylation of SRSF1 offer a promising therapeutic target for treatment of pediatric ALL.