VEGFR2 inhibition by RNA interference affects cell proliferation, migration, invasion, and response to radiation in Calu-1 cells

Production and Conjugation of Truncated Recombinant Diphtheria Toxin to VEGFR-2 Specific Nanobody and Evaluation of its Cytotoxic Effect on PC-3 Cell Line

Immunotoxins have represented a great potency in targeted therapeutics to encounter tumors. They consist of a protein toxin conjugated to a targeting moiety, which recognizes a specific antigen on surface of cancer cells and accordingly induces cell death by toxin segment. The targeting part could be a nanobody, which is a group of antibodies composed of an only functional single variable heavy chain (VHH).Therefore, this study was done to produce an immunotoxin (VGRNb-DT) by chemical conjugation of a truncated diphtheria toxin moiety to an anti-vascular endothelial growth factor receptor 2(VEGFR-2) nanobody, and to identify effectiveness of immunotoxin in recognizing the VEGFR-2- positive cancer cells and inhibiting cell growth and survival. Diphtheria toxin was expressed and purified by nickel affinity chromatography, and accordingly, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot analysis confirmed its expression. Function of heterobifunctional crosslinkers, Sulfo-SMCC (sulfosuccinimidyl-4-(N-maleimidomethyl) cyclohexane-1-carboxylate), and SATP (N-succinimidyl-S- acetylthiopropionate) for bioconjugation purposes was acknowledged by cation exchange high-performance liquid chromatography (HPLC). Cytotoxicity of immunotoxin was evaluated on the VEGFR-2 positive PC-3 cell line by MTT assay. Overexpression of VEGFR-2 in the PC-3 cell line allowed immunotoxin to recognize them by anti-VEGFR-2 nanobodies. The concentrations above 5 μg/ml represented a significant decrease in cell survival rate in PC-3 cells compared to HEK293 cells (VEGFR-2 negative cells) as controls.VGRNb-DT demonstrated a successful bioconjugation; furthermore, variable concentrations were correlated with cell death in prostate cancer PC-3 cells.

The effect and mechanism of miR-607/CANT1 axis in lung squamous carcinoma

Lung squamous carcinoma (LUSC) is the second most frequent subtype of non-small cell lung cancer. Rarely gene alterations are identified in LUSC. Therefore, identifying LUSC-related genes to explain the relevant molecular mechanism is urgently needed. A potential biomarker, calcium-activated nucleotidase 1 (CANT1), was elevated in tissues of LUSC patients relative to normal cases based on the TCGA and/or GTEx database. CCK-8 and transwell tests were then implemented to measure the proliferative, invasive and migratory capacities, and showed that knockdown of CANT1 blocked LUSC cells proliferation. miR-607, predicted as an upstream factor for CANT1, was declined in LUSC using TargetScan analysis and luciferase activity test. Low miR-607 expression was related with unfavorable outcomes of LUSC patients. Moreover, miR-607 downregulation elevated cell viability, invasion and migration in LUSC cells, which was antagonized by si-CANT1. GEPIA website was accessed to estimate the relevance between CANT1 and epithelial-mesenchymal transition (EMT)-related positive factors. The protein levels of Fibronectin, Vimentin, Snail and β-catenin were altered due to the abnormal CANT1 and miR-607 expression. Together, these data unveiled that miR-607/CANT1 pair may exert a vital role in the progression of LUSC through mediating EMT process, which would furnish an available therapeutic therapy for LUSC.

Mechanisms and Clinical Trials of Hepatocellular Carcinoma Immunotherapy

Hepatocellular carcinoma (HCC), one of the most common and lethal tumors worldwide, is usually not diagnosed until the disease is advanced, which results in ineffective intervention and unfavorable prognosis. Small molecule targeted drugs of HCC, such as sorafenib, provided only about 2.8 months of survival benefit, partially due to cancer stem cell resistance. There is an urgent need for the development of new treatment strategies for HCC. Tumor immunotherapies, including immune check point inhibitors, chimeric antigen receptor T cells (CAR-T) and bispecific antibodies (BsAb), have shown significant potential. It is known that the expression level of glypican-3 (GPC3) was significantly increased in HCC compared with normal liver tissues. A bispecific antibody (GPC3-S-Fabs) was reported to recruit NK cells to target GPC3 positive cancer cells. Besides, bispecific T-cell Engagers (BiTE), including GPC3/CD3, an aptamer TLS11a/CD3 and EpCAM/CD3, were recently reported to efficiently eliminate HCC cells. It is known that immune checkpoint proteins programmed death-1 (PD-1) binding by programmed cell death-ligand 1 (PD-L1) activates immune checkpoints of T cells. Anti-PD-1 antibody was reported to suppress HCC progression. Furthermore, GPC3-based HCC immunotherapy has been shown to be a curative approach to prolong the survival time of patients with HCC in clinically trials. Besides, the vascular endothelial growth factor (VEGF) inhibitor may inhibit the migration, invasion and angiogenesis of HCC. Here we review the cutting-edge progresses on mechanisms and clinical trials of HCC immunotherapy, which may have significant implication in our understanding of HCC and its immunotherapy.

The Effect of GLUT1 on Survival Rate and the Immune Cell Infiltration of Lung Adenocarcinoma and Squamous Cell Carcinoma: A Meta and Bioinformatics Analysis

BACKGROUND

Lung adenocarcinoma (LUAD) and squamous cell carcinoma (LUSC) are two major subtypes of non-small cell lung cancer (NSCLC). Studies have shown that abnormal expression of glucose transport type 1 (GLUT1) in NSCLC patients has been associated with progression, aggressiveness, and poor clinical outcome. However, the clinical effect of GLUT1 expression on LUAD and LUSC is unclear.

OBJECTIVE

This study aims to learn more about the character of GLUT1 in LUAD and LUSC.

METHODS

A meta-analysis was performed to evaluate the GLUT1 protein level, and bioinformatics analysis was used to detect the GLUT1 mRNA expression level, survival differences, and the infiltration abundance of immune cells in samples from TCGA. Meanwhile, functional and network analysis was conducted to detect important signaling pathways and key genes with the Gene Expression Omnibus (GEO) dataset.

RESULTS

Our results showed that GLUT1 was over-expressed both in LUAD and LUSC. LUAD patients with high GLUT1 expression had a poor prognosis. Additionally, GLUT1 was related to B cell and neutrophil infiltration of LUAD. In LUSC, GLUT1 was correlated with tumor purity, B cell, CD8⁺ T cell, CD4⁺ T cell, macrophage, neutrophil, and dendritic cell infiltration. The GEO dataset analysis results suggested GLUT1 potentially participated in the p53 signaling pathway and metabolism of xenobiotics by cytochrome P450 and was associated with KDR, TOX3, AGR2, FOXA1, ERBB3, ANGPT1, and COL4A3 gene in LUAD and LUSC.

CONCLUSION

GLUT1 might be a potential biomarker for aggressive progression and poor prognosis in LUAD, and a therapeutic biomarker in LUSC.

Apatinib suppresses the migration, invasion and angiogenesis of hepatocellular carcinoma cells by blocking VEGF and PI3K/AKT signaling pathways

Hepatocellular carcinoma (HCC) is a commonly diagnosed malignancy worldwide with poor prognosis and high metastasis and recurrence rates. Although apatinib has been demonstrated to have potential antitumor activity in multiple solid tumors, the underlying mechanism of apatinib in HCC treatment remains to be elucidated. In the present study, apatinib were used to treat HCC cells transfected with or without VEGFR2 overexpression vectors. The proliferation of HCC cells was detected by MTT assay. The migration and invasion of HCC cells were detected by wound healing assay and Transwell assay. The ability of angiogenesis of HCC cells were detected by tube formation assay. The related protein expression levels were detected by western blotting. The present study aims to investigate the effect and potential mechanism of apatinib on the migration, invasion and angiogenesis of HCC cells. It was found that apatinib treatment significantly inhibited the proliferation, migration and invasion of Hep3b cells and suppressed angiogenesis in HUVECs. In addition, apatinib inhibited the epithelial‑mesenchymal transition of Hep3b cells by increasing the expression of the epithelial hallmarks E‑cadherin and α‑catenin and decreased the expression of the mesenchymal hallmarks N‑cadherin and vimentin. These effects were associated with the downregulation of VEGF and VEGFR2 and suppression of the PI3K/AKT signaling pathway. Thus, apatinib inhibited cell migration, invasion and angiogenesis by blocking the VEGF and PI3K/AKT pathways, supporting an effective therapeutic strategy in the treatment of HCC.

SUMOylation of vascular endothelial growth factor receptor 2 inhibits the proliferation, migration, and angiogenesis signaling pathway in non-small cell lung cancer

Vascular endothelial growth factor receptor 2 (VEGFR2) is highly expressed in non-small cell lung cancer (NSCLC), and is the main target of antiangiogenesis therapy against this disease. However, there is limited evidence regarding its regulatory mechanism. Thus, elucidating the underlying mechanism of regulation of VEGFR2 is of great value to antiangiogenesis therapy. The colocalization of VEGFR2 and small ubiquitin-like modifier 1 (SUMO1) was detected through confocal microscopy. We examined the level of VEGFR2 SUMOylation in cells and rat tissues, and its effects on the angiogenesis signaling pathway (immunoprecipitation and western blotting), as well as the proliferation (Cell Counting Kit-8 assay) and migratory ability (cell scratch and Transwell assays) of NSCLC cells. Apoptosis was evaluated through Hoechst staining. VEGFR2 and SUMO1 are colocalized in the cytoplasm. VEGFR2 can be SUMOylated through combination with SUMO1 in cells and rat tissues, and the level of VEGFR2 SUMOylation in NSCLC is higher than that observed in healthy cells and tissues. Cell proliferation, migration, and the protein levels of phosphorylated-VEGFR2/phosphorylated-Akt/phosphorylated-extracellular signal-regulated kinase 1/2 (p-VEGFR2/p-Akt/p-ERK1/2) were significantly increased in NSCLC cells transfected with VEGFR2 K1270R versus those reported in cells transfected with VEGFR2 (wild-type). The levels of p-VEGFR2/p-Akt/p-ERK1/2 protein were significantly decreased in cells transfected with sentrin-specific protease 1-targeting small interfering RNA (siSENP1) versus those recorded in nontransfected controls. VEGFR2 SUMOylation may play an important role in antiangiogenesis therapy of NSCLC. The level of VEGFR2 SUMOylation may be a prognostic marker in patients with NSCLC.

Prioritization of genes involved in endothelial cell apoptosis by their implication in lymphedema using an analysis of associative gene networks with ANDSystem

BACKGROUND

Currently, more than 150 million people worldwide suffer from lymphedema. It is a chronic progressive disease characterized by high-protein edema of various parts of the body due to defects in lymphatic drainage. Molecular-genetic mechanisms of the disease are still poorly understood. Beginning of a clinical manifestation of primary lymphedema in middle age and the development of secondary lymphedema after treatment of breast cancer can be genetically determined. Disruption of endothelial cell apoptosis can be considered as one of the factors contributing to the development of lymphedema. However, a study of the relationship between genes associated with lymphedema and genes involved in endothelial apoptosis, in the associative gene network was not previously conducted.

METHODS

In the current work, we used well-known methods (ToppGene and Endeavour), as well as methods previously developed by us, to prioritize genes involved in endothelial apoptosis and to find potential participants of molecular-genetic mechanisms of lymphedema among them. Original methods of prioritization took into account the overrepresented Gene Ontology biological processes, the centrality of vertices in the associative gene network, describing the interactions of endothelial apoptosis genes with genes associated with lymphedema, and the association of the analyzed genes with diseases that are comorbid to lymphedema.

RESULTS

An assessment of the quality of prioritization was performed using criteria, which involved an analysis of the enrichment of the top-most priority genes by genes, which are known to have simultaneous interactions with lymphedema and endothelial cell apoptosis, as well as by genes differentially expressed in murine model of lymphedema. In particular, among genes involved in endothelial apoptosis, KDR, TNF, TEK, BMPR2, SERPINE1, IL10, CD40LG, CCL2, FASLG and ABL1 had the highest priority. The identified priority genes can be considered as candidates for genotyping in the studies involving the search for associations with lymphedema.

CONCLUSIONS

Analysis of interactions of these genes in the associative gene network of lymphedema can improve understanding of mechanisms of interaction between endothelial apoptosis and lymphangiogenesis, and shed light on the role of disturbance of these processes in the development of edema, chronic inflammation and connective tissue transformation during the progression of the disease.

Effects of combined inhibition of STAT3 and VEGFR2 pathways on the radiosensitivity of non-small-cell lung cancer cells

Purpose

The goals of this study were to determine the effects of combined inhibition of STAT3 and vascular endothelial growth factor receptor 2 (VEGFR2) pathways on the radiosensitivity of non-small-cell lung cancer (NSCLC) cells, and to assess the underlying mechanisms.

Methods

The expressions of VEGFR2, STAT3, related signaling molecules, hypoxia-inducible factor 1-alpha (HIF-1α), and cyclin D1 were determined by Western blotting. Radiosensitivity was assessed using the colony-forming assay, and cell cycle and cell death were analyzed by flow cytometry. A nude mouse xenograft tumor model of Calu-1 cells was established. The hepatorenal toxicity of the above-mentioned treatment on tumor-bearing mice was observed by H&E staining. The expression of STAT3, VEGFR2, HIF-1α, and cyclin D1 of the transplanted tumor tissues was detected by immunohistochemistry. Apoptosis of tumor tissues was evaluated by TUNEL staining.

Results

In vitro, we selected two cell lines with high expression levels of STAT3, including Calu-1 cells that exhibit high VEGFR2 expression and A549 cells that exhibit low VEGFR2 expression. When apatinib treatment was combined with S3I-201, the expression of VEGFR2, STAT3, and their downstream signaling molecules was significantly decreased (P<0.01). There was an increase in cell death and G2/M phase arrest after treatments, with the most significant changes occurring upon dual inhibition of STAT3 and VEGFR2 (P<0.01). In vivo, combined treatment of radiotherapy and dual inhibition of VEGFR2 and STAT3 was well tolerated and did not deliver additional toxicity. Compared with the control group and the radiation treatment (RT) + apatinib or RT + S3I-201 duplex group, the expression level of STAT3, p-STAT3, VEGFR2, HIF-1α, and cyclin D1 in the triple group (RT + apatinib + S3I-201) was the lowest, and the proportion of apoptotic cells was the highest (P<0.05).

Conclusion

The combined inhibition of VEGFR2 and STAT3 is effective in enhancing radiosensitizing effects in NSCLC cells.

Apatinib affect VEGF-mediated cell proliferation, migration, invasion via blocking VEGFR2/RAF/MEK/ERK and PI3K/AKT pathways in cholangiocarcinoma cell

BACKGROUND

Cholangiocarcinoma (CCA) is a form of cancer that easily aggress to contiguous structures. Vascular endothelial growth factor (VEGF) and VEGF receptor 2 (VEGFR2) are increased in majority species of cancers and suppress tumor progression by blocking VEGF/VEGFR2. Apatinib is a highly selective VEGFR2 antagonist which has inhibitive effect on antiapoptotic and cell growth in CCA. While, the effect of apatinib cell migration and invasion in CCA is still unknown.

METHODS

CCA cell lines QBC939 and TFK-1 were transfected with siKDR to establish the KDR function loss cell model, and recombined human VEGF (rhVEGF) protein was added into the culture medium to enhance the VEGF expression. RT-qPCR and western bloting were used to detect the mRNA and protein expression levels of VEGFR2 to investigate whether it was effectively repressed or activated with rhVEGF or apatinib treatment. Then, MTT, wound healing assay, and transwell matrix assay were applied to measure the effect of apatinib and rhVEGF on cell viability, migration and invasion, respectively.

RESULTS

The mRNA and protein expressions of VEGFR2 were significantly reduced with KDR RNAi in both QBC939 and TFK-1 cells, and rhVEGF treatment increased these expression levels (p < 0.05). Apatinib dramatically suppressed VEGF-mediated cell migration and invasion at the concentration of 100 nM treatment and significantly decreased the expression of metastasis-associated protein such as Slug, snail and MMP9. Moreover, all of these inhibiting effects of apatinib depended on the VEGFR2 existence. In addition, VEGFR2/RAF/MEK/ERK and PI3K/AKT signal pathways were enhanced by the introduction of rhVEGF, but were dramatically suppressed after the apatinib treatment.

CONCLUSION

Apatinib inhibit VEGF-mediated cell migration and invasion in CCA cell lines via inhibiting the VEGFR2/RAF/MEK/ERK and PI3K/AKT pathways. It will be a potentially effective targeted drug for CCA.

Antitumor effects of Tubeimoside-1 in NCI-H1299 cells are mediated by microRNA-126-5p-induced inactivation of VEGF-A/VEGFR-2/ERK signaling pathway

Tubeimoside-1 (TBMS1), a triterpenoid saponin isolated from the tuber of Bolbostemma paniculatum (Maxim) Franquet, serves an universal suppressive role in multiple cancer types, including lung cancer. However, the mechanism involved in non-small cell lung cancer (NSCLC) cells by which TBMS1 elicits its antitumor effects is not yet completely understood. The present study indicated that 10 µmol/l TBMS1 significantly enhanced apoptosis and notably blocked the migration and invasion of NCI-H1299 cells. These effects were reversed following transfection with miR-126-5p inhibitor into TBMS1-treated NCI-H1299 cells. Vascular endothelial growth factor-A (VEGF-A) is a target gene for miR-126-5p. Notably, results suggested that the downregulated VEGF-A and VEGFR-2 in TBMS1-treated NCI-H1299 cells were upregulated after inhibiting miR-126-5p, and overexpression of VEGF-A or VEGFR-2 could significantly reduce apoptosis and promote the migration and invasion of TBMS1-treated NCI-H1299 cells. Furthermore, TBMS1 combined with TBHQ (an ERK activator) dramatically suppressed TBMS1-induced apoptosis and stimulated TBMS1-reduced migration and invasion in NCI-H1299 cells, suggesting that TBMS1 inhibits the ERK signaling pathway and represses the growth and metastasis of NCI-H1299 cells. Further study demonstrated that either inhibiting miR-126-5p or overexpressing VEGF-A and VEGFR-2 in TBMS1-treated NCI-H1299 cells elevated the mRNA expression levels and phosphorylation levels of MEK1, as well as ERK. To conclude, TBMS1 increases miR-126-5p expression, whereas overexpressing miR-126-5p inactivates VEGF-A/VEGFR-2/ERK signaling pathway, which ultimately actuates the pro-apoptotic and anti-metastatic effects in NCI-H1299 cells. Therefore, the present findings provide a theoretical foundation for TBMS1 as a potential candidate in NSCLC treatment.

Rhamnazin attenuates inflammation and inhibits alkali burn-induced corneal neovascularization in rats

The purpose of our study was to determine whether rhamnazin inhibits corneal neovascularization in the rat alkali burn model, and alleviates the inflammatory response of the cornea. Rhamnazin inhibited the proliferation of HUVEC cells in a dose-dependent manner, and it also inhibited the migration and luminal formation of HUVEC cells. 20 μM rhamnazin eye drops were applied to an animal model of corneal alkali burn neovascularization 4 times a day for 14 days. The corneal neovascularization in the rhamnazin group was obviously less than that in the PBS control group. In the rhamnazin group, the inflammatory index of the cornea decreased gradually over time, whereas the inflammatory index of the PBS group decreased only slightly with time. The corneal CNV area in the PBS group was significantly larger than that in the rhamnazin group. The expression level of VEGF protein of the rhamnazin group was lower than that in the PBS group, and the expression level of PEDF was significantly higher than that of the PBS group. Rhamnazin downregulated the expression of VEGFR2 protein and decreased the expression levels of p-STAT3, p-MAPK and p-Akt proteins. This study provides a new idea for the study of the molecular mechanism of corneal neovascularization.

The purpose of our study was to determine whether rhamnazin inhibits corneal neovascularization in the rat alkali burn model, and alleviates the inflammatory response of the cornea.