ILT4 facilitates angiogenesis in non-small cell lung cancer.

Antiangiogenic therapy targeting VEGF-A has become the standard of first-line therapy for non-small cell lung cancer (NSCLC). However, its clinical response rate is still less than 50%, and most patients eventually develop resistance, even when using combination therapy with chemotherapy. The major cause of resistance is the activation of complex bypass signals that induce angiogenesis and tumor progression. Therefore, exploring novel proangiogenic mechanisms and developing promising targets for combination therapy are crucial for improving the efficacy of antiangiogenic therapy. Immunoglobulin-like transcript (ILT) 4 is a classic immunosuppressive molecule that inhibits myeloid cell activation. Recent studies have shown that tumor cell-derived ILT4 drives tumor progression via the induction of malignant biologies and creation of an immunosuppressive microenvironment. However, whether and how ILT4 participates in NSCLC angiogenesis remain elusive. Herein, we found that enriched ILT4 in NSCLC is positively correlated with high microvessel density, advanced disease, and poor overall survival. Tumor cell-derived ILT4 induced angiogenesis both in vitro and in vivo and tumor progression and metastasis in vivo. Mechanistically, ILT4 was upregulated by its ligand angiopoietin-like protein 2 (ANGPTL2). Their interaction subsequently activated the ERK1/2 signaling pathway to increase the secretion of the proangiogenic factors VEGF-A and MMP-9, which are responsible for NSCLC angiogenesis. Our study explored a novel mechanism for ILT4-induced tumor progression and provided a potential target for antiangiogenic therapy in NSCLC.

Perivascular tenascin C triggers sequential activation of macrophages and endothelial cells to generate a pro-metastatic vascular niche in the lungs.

Disseminated cancer cells frequently lodge near vasculature in secondary organs. However, our understanding of the cellular crosstalk invoked at perivascular sites is still rudimentary. Here, we identify intercellular machinery governing formation of a pro-metastatic vascular niche during breast cancer colonization in the lung. We show that specific secreted factors, induced in metastasis-associated endothelial cells (ECs), promote metastasis in mice by enhancing stem cell properties and the viability of cancer cells. Perivascular macrophages, activated via tenascin C (TNC) stimulation of Toll-like receptor 4 (TLR4), were shown to be crucial in niche activation by secreting nitric oxide (NO) and tumor necrosis factor (TNF) to induce EC-mediated production of niche components. Notably, this mechanism was independent of vascular endothelial growth factor (VEGF), a key regulator of EC behavior and angiogenesis. However, targeting both macrophage-mediated vascular niche activation and VEGF-regulated angiogenesis resulted in added potency to curb lung metastasis in mice. Together, our findings provide mechanistic insights into the formation of vascular niches in metastasis.

Luteolin inhibits viability, migration, angiogenesis and invasion of non-small cell lung cancer vascular endothelial cells via miR-133a-3p/purine rich element binding protein B-mediated MAPK and PI3K/Akt signaling pathways.

Luteolin inhibits tumorigenesis of non-small cell lung cancer (NSCLC), but its mechanism still needs to be clarified. We hereby explored the effects of luteolin in vascular endothelial cells of NSCLC (NSCLC-VECs). After extraction and identification of NSCLC-VECs, cells were treated with luteolin and transfected. The viability, migration, angiogenesis and invasion of the cells were measured. The levels of miR-133a-3p, purine rich element binding protein B (PURB), vascular endothelial growth factor (VEGF), phosphatidylinositol 3-kinase (PI3K), Akt, mitogen-activated protein kinases (MAPK), matrix metalloproteinase (MMP)-2/-9 were determined. The interaction relationship of miR-133a-3p and PURB was identified. Luteolin inhibited the viability, migration, angiogenesis and invasion of NSCLC-VECs yet up-regulated miR-133a-3p level, while miR-133a-3p inhibitor counteracted the repressive effect of luteolin on the viability, migration, angiogenesis, and invasion in NSCLC-VECs. Luteolin inhibited the expressions of migration- and invasion-associated proteins (VEGF, MMP-2 and MMP-9), PI3K/Akt and MAPK signaling pathways-related factors, while miR-133a-3p inhibitor reversed the inhibitory effect of Luteolin on NSCLC-VECs. Luteolin decreased the level of PURB, which was targeted by miR-133a-3p. ShPURB promoted miR-133a-3p level in NSCLC-VECs, while reversing the promoting effects of miR-133a-3p inhibitor on the migration, invasion, and levels of migration- and invasion-associated proteins, PI3K/Akt and MAPK pathways-associated factors in NSCLC-VECs. Collectively speaking, luteolin inhibits the migration and invasion of NSCLC-VECs via miR-133a-3p/PURB- mediated MAPK and PI3K/Akt pathways.

The Change of Soluble Programmed Death Ligand 1 (sPD-L1) in Plasma of Small Cell Lung Cancer and Its Clinical Significance.

Background soluble programmed death-ligand 1 (sPD-L1) expression in lung squamous cell carcinoma and lung adenocarcinoma is associated with disease progression, and sPD-L1 expression in small cell lung cancer (SCLC) may have similar manifestations and become a potential marker for treatment. The purpose of this study was to observe the changes of plasma sPD-L1 expression in SCLC patients. Methods. 90 patients diagnosed with SCLC from January 2019 to November 2020 were selected as the test group, including 72 males and 18 women, 58.7 ± 6.6 years; 30 healthy subjects were selected from the physical examination center, including 18 males, 12 females, and 60.3 ± 7.0 years. There were no statistical difference in sex and age factors between the trial and control groups (p > 0.05). Selected SCLC used chemotherapy regimen: cisplatin + etoposide (EP), carboplatin + etoposide (CE), and SCLC group were divided into three subgroups of disease progression group, partial remission group, and disease stability group according to the treatment effect. Comparison of the differences in sPD-L1 expression content between the experimental and control populations. Plasma sPD-L1 levels were dynamically monitored pre- and posttreatment in 90 patients with small-cell lung cancer and were associated with efficacy among subgroups. Meanwhile, the risk factors for patient sPD-L1 expression content were analyzed by logistic regression. Results. Plasma sPD-L1 levels were higher in the SCLC group than in the healthy people group (t = 7.40, p < 0.01). In the disease progression group of the SCLC group, sPD-L1 levels were decreased in the SCLC group, sPD-L1 in some remission group was increased after treatment, and sPD-L1 levels in the disease-stable group (p > 0.05). Multivariate logistic regression analysis showed that factors promoting increased sPD-L1 expression in SCLC patients included increased smoking, brain metastasis, and ProGRP expression (both p values < 0.05). Conclusion. (1) Higher peripheral sPD-L1 expression in SCLC patients than in healthy patients, and the expression levels were closely related to efficacy. (2) Dynamic changes in s PD-L1 were correlated with clinical efficacy. (3) The progression of sPD-L1 and ProGRP in SCLC patients showed the same extent during remission and stabilization, suggesting the effect of s PD-L1 in the evaluation of SCLC tumors and the reflection of the tumor marker ProGRP.

Predictive value of microvascular density for response to anlotinib in advanced NSCLC.

ABSTRACT: Nonsmall cell lung cancer (NSCLC) is the most common type of lung cancer. This study aimed to categorize the microvessels in advanced NSCLC and determine the relationship between intratumoral microvascular density (MVD) and the efficacy of anlotinib for NSCLC.The clinical data of 68 patients receiving anlotinib as third-line treatment or beyond for advanced NSCLC were retrospectively collected. Microvessels were stained for CD31 and CD34 by using immunohistochemical staining and were classified as undifferentiated (CD31+ CD34-) and differentiated vessels (CD31+ CD34+). The relationship between MVD and anlotinib efficacy and patient prognosis was analyzed.Patients were divided into the high or low MVD groups according to the median MVD of differentiated (9.4 vessels/field) and undifferentiated microvessels (6.5 vessels/field). There were significantly more patients with high undifferentiated-vessel MVD in the disease control group than in the disease progression group (72.7% vs 16.7%, P < .001). Patients with high undifferentiated-vessel MVD had significantly longer median progression-free survival than those with low undifferentiated-vessel MVD (7.1 vs 3.7 months, P < .001).Anlotinib as third- or beyond line therapy is safe and effective for advanced NSCLC. Patients with a higher density of undifferentiated microvessels have better response to anlotinib and longer progression-free survival.

The CT and PET/CT findings in primary pulmonary lymphoepithelioma-like carcinoma with pathological correlation: a study of 215 cases.

AIM: To investigate the computed tomography (CT) and integrated positron-emission tomography (PET)/CT findings of primary pulmonary lymphoepithelioma-like carcinoma (PLELC). MATERIALS AND METHODS: The imaging and histopathological data of 215 patients with PLELC confirmed at histopathology were analysed retrospectively. All patients underwent CT, and 70 underwent PET/CT. None of the cohort had nasopharyngeal lymphoepithelioma-like carcinoma. RESULTS: The PLELC was demonstrated as a solitary nodule/mass in 188 cases (188/215, 87%), multiple nodules/masses in 12 cases (12/215, 6%), lobar or segmental consolidation in 15 cases (15/215, 7%). The tumour showed a well-defined margin in 171 cases (171/215, 80%), lobular sign in 177 cases (177/215, 82%), and spicule sign in 91 cases (91/215, 42%). Most of the cases showed homogeneous density in unenhanced CT (128/215, 60%), and vascular shadows inside the tumour in the arterial stage were found in 105 cases (105/158, 66%). Involvement of the bronchus was found in 154 cases (154/215, 72%). Hilar or mediastinal lymph nodes were enlarged in 160 patients (160/215, 74%). Seventy cases demonstrated avid 2-[18F]-fluoro-2-deoxy-d-glucose (FDG) uptake on PET/CT. The range of maximum standardised uptake values (SUVmax) was 2.1-28.5 (14 ± 5.93). Microscopic pathological classification of 124 resected specimens included 87 cases of the Regaud type and 37 cases of the Schmincke type. Epstein-Barr virus (EBV)-encoded small RNAs (EBERs) was positive in all 215 cases. CONCLUSION: PLELC should be suspected when a large, lobulate, well-defined lung tumour with homogeneous density, vascular encasement, and high 18F-FDG uptake is found. Moreover, EBERs are helpful in patients with suspected PLELC.

Serum levels of VCAM-1 are associated with survival in patients treated with nivolumab for NSCLC.

BACKGROUND: High circulating levels of cellular adhesion molecules (CAMs) in non-small cell lung cancer (NSCLC) have been supposed to act as a negative prognostic factor. Here, we explored the predictive role of pre-treatment levels of CAMs in previously treated patients receiving nivolumab for NSCLC. MATERIALS AND METHODS: Seventy one patients with advanced NSCLC, treated with nivolumab at the dose of 3 mg/kg every 14 days, were enrolled. Maximum follow-up time was 3 years. Serum levels of Vascular Cell Adhesion Molecule-1 (VCAM-1) and Intracellular Adhesion Molecule-1 (ICAM-1) were measured at baseline and before each nivolumab administration. Endpoints of the study were a composite outcome of survival ≥2 years or absence of disease progression at the end of the follow-up, and the overall survival. RESULTS: Composite outcome and overall survival were positively associated with VCAM-1 baseline levels and with the reduction of VCAM-1 during the treatment. After adjustment for potential confounders, the change in VCAM-1 serum levels during the treatment was an independent predictor of overall survival. CONCLUSIONS: High baseline serum levels of VCAM-1 are associated with a longer survival in patients treated with nivolumab as second line treatment for NSCLC. Surviving patients experience also a significant reduction in CAMs expression during the treatment. Hence, CAMs might be promising prognostic factors in patients with NSCLC underoing immunotherapy.

Angiogenesis inhibition in lung cancer: emerging novel strategies.

PURPOSE OF REVIEW: In the current review, we will explore the molecular bases that have determined the design of clinical trials exploring the efficacy of antivascular agents in combination with chemotherapy, immune check point inhibitors and epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) in patients with advanced nonsmall cell lung cancer. RECENT FINDINGS: Recent clinical trials have demonstrated the synergistic effect of antivascular agents with immune checkpoint inhibitors and EGFR-TKIs, despite no molecular marker has been identified yet to select patients. SUMMARY: Lung cancer remains one of the first causes of cancer-related death. However, thanks to the development of stratified molecular medicine and the introduction of immune checkpoint inhibitors, patients' survival has significantly improved. Due to the critical role of pro-angiogenic factors in cancer progression, antivascular agents targeting the vascular endothelial growth factor (VEGF) and its receptor (VEGFR) have been developed. Their efficacy has been explored in combination with chemotherapy, and immune checkpoint inhibitors, with promising but not definitive conclusions about their impact on prolonging patients' survival.

Left Lower Lobectomy in a Patient With Absence of Pulmonary Artery Branching Into the Lobe.

Here, we report a case in which we resected non-small cell lung cancer of the left lower lobe and detected an anomaly in the resected lobe. Three-dimensional computed tomography showed more detailed information on this anomaly than the conventional one. Because we recognized the information regarding the anomaly before the operation, we accomplished left lower lobectomy and an uneventful postoperative course. If carcinoma had existed in the other lobe, the intraoperative and postoperative course would have become more serious. Therefore, it is essential to pay attention to the information regarding anatomic abnormality when resecting malignant tumors.

PIGF and Flt-1 on the surface of macrophages induces the production of TGF-ß1 by polarized tumor-associated macrophages to promote lung cancer angiogenesis.

BACKGROUND: The interaction between tumor cells and tumor microenvironment is a necessary condition for promoting the metastasis of malignant tumors. METHODS: Two different transwell culture systems were interfered with by recombinant factor placental growth factor (re-PIGF) and the re-PIGF + transforming growth factor-ß1 (TGF-ß1)-neutralizing antibody (anti-TGF-ß1). We performed immunofluorescence, flow cytometry and enzyme linked immunosorbent assay (ELISA) to analyze the expression of PIGF, fms-like tyrosine kinase-1 (Flt-1), macrophage marker F4/80 +, macrophage M2 marker CD163+ and TGF-ß1 in vitro. Meanwhile, cell viability assay and optical microscope assay were conducted to explore the cell viability and vascularization ability of human umbilical vein endothelial cells (HUVECs). RESULTS: Re-PIGF increased the expression of PIGF in A549 cells and the expression of Flt-1 in BM-Mac cells, and significantly enhanced the ability of bone marrow-derived macrophages (BM-Mac) to transform into macrophages. At the same time, re-PIGF increased the expression of cytokine TGF-ß1 in A549 cells/BM-Mac transwell culture system. On the contrary, re-PIGF + anti-TGF-ß1 inhibited the expression of Flt-1 in BM-Mac cells and inhibited the ability of BM-Mac cells to transform into macrophages. Finally, re-PIGF + anti-TGF-ß1 reduced the cell viability and angiogenesis of HUVECs. CONCLUSION: The surface molecule PIGF of lung cancer cells could bind to the receptor Flt-1 on the surface of macrophages, thereby increasing the production of TGF-ß1, and ultimately promoting the formation of angiogenesis in lung cancer.

Chemotherapy-Induced Changes in the Lung Microenvironment: The Role of MMP-2 in Facilitating Intravascular Arrest of Breast Cancer Cells.

Previously, we showed that mice treated with cyclophosphamide (CTX) 4 days before intravenous injection of breast cancer cells had more cancer cells in the lung at 3 h after cancer injection than control counterparts without CTX. At 4 days after its injection, CTX is already excreted from the mice, allowing this pre-treatment design to reveal how CTX may modify the lung environment to indirectly affect cancer cells. In this study, we tested the hypothesis that the increase in cancer cell abundance at 3 h by CTX is due to an increase in the adhesiveness of vascular wall for cancer cells. Our data from protein array analysis and inhibition approach combined with in vitro and in vivo assays support the following two-prong mechanism. (1) CTX increases vascular permeability, resulting in the exposure of the basement membrane (BM). (2) CTX increases the level of matrix metalloproteinase-2 (MMP-2) in mouse serum, which remodels the BM and is functionally important for CTX to increase cancer abundance at this early stage. The combined effect of these two processes is the increased accessibility of critical protein domains in the BM, resulting in higher vascular adhesiveness for cancer cells to adhere. The critical protein domains in the vascular microenvironment are RGD and YISGR domains, whose known binding partners on cancer cells are integrin dimers and laminin receptor, respectively.

Tumor-derived exosomal miR-3157-3p promotes angiogenesis, vascular permeability and metastasis by targeting TIMP/KLF2 in non-small cell lung cancer.

Metastasis is the main cause of death in patients with advanced lung cancer. The exosomes released by cancer cells create tumor microenvironment, and then accelerate tumor metastasis. Cancer-derived exosomes are considered to be the main driving force for metastasis niche formation at foreign sites, but the mechanism in Non-small cell lung carcinoma (NSCLC) is unclear. In metastatic NSCLC patients, the expression level of miR-3157-3p in circulating exosomes was significantly higher than that of non-metastatic NSCLC patients. Here, we found that miR-3157-3p can be transferred from NSCLC cells to vascular endothelial cells through exosomes. Our work indicates that exosome miR-3157-3p is involved in the formation of pre-metastatic niche formation before tumor metastasis and may be used as a blood-based biomarker for NSCLC metastasis. Exosome miR-3157-3p has regulated the expression of VEGF/MMP2/MMP9 and occludin in endothelial cells by targeting TIMP/KLF2, thereby promoted angiogenesis and increased vascular permeability. In addition, exosome miR-3157-3p promoted the metastasis of NSCLC in vivo.

Thalidomide suppresses angiogenesis and immune evasion via lncRNA FGD5-AS1/miR-454-3p/ZEB1 axis-mediated VEGFA expression and PD-1/PD-L1 checkpoint in NSCLC.

BACKGROUND: Non-small cell lung cancer (NSCLC) accounts for about 80-85% of total lung cancer cases. Identifying the molecular mechanisms of anti-tumor drugs is essential for improving therapeutic effects. Herein, we aim to investigate the role of thalidomide in the tumorigenicity of NSCLC. METHODS: The A549 xenograft nude mouse model was established to explore therapeutic effects of thalidomide. The expression of FGD5-AS1 was evaluated in carcinomatous and paracarcinomatous tissues from NSCLC patients as well as NSCLC cell lines. CCK-8 assay was performed to assess cell viability. The invasive capacity was examined using transwell assay. The tube formation assay was applied to determine cell angiogenesis. Flow cytometry was subjected to validate CD8+ T cell activity. The FGD5-AS1/miR-454-3p/ZEB1 regulatory network was analyzed using luciferase reporter, RIP and ChIP assays. RESULTS: Thalidomide reduced tumor growth and angiogenesis and increased CD8+ T cell ratio in a mouse model. Enhanced expression of FGD5-AS1 was positively correlated with the poor survival of NSCLC patients. Knockdown of FGD5-AS1 notably suppressed the proliferation, invasion and angiogenesis of cancer cells as well as the apoptosis of CD8+ T cells. Thalidomide targeted FGD5-AS1 to exert its anti-tumor activity in NSCLC. FGD5-AS1 acted as a sponge of miR-454-3p to upregulate ZEB1, thus increasing the expression of PD-L1 and VEGFA. Simultaneous overexpression of FGD5-AS1 and silencing of miR-454-3p reversed thalidomide-mediated anti-tumor effects in NSCLC. CONCLUSION: Thalidomide inhibits NSCLC angiogenesis and immune evasion via FGD5-AS1/miR-454-3p/ZEB1 axis-mediated regulation of VEGFA expression and PD-1/PD-L1 checkpoint.

MiR-22-3p Expression is down-regulated in lung adenocarcinoma.

BACKGROUND: Our current study was performed with an attempt to detect the expression of microRNA-22-3p (miR-22-3p) in lung adenocarcinoma, as well as to analyze its role in clinical practice. In addition, its relationship with vascular endothelial growth factor (VEGF) and metastasis related indexes was focused. MATERIAL AND METHOD: The trials in which 62 cases of lung adenocarcinoma were received to collect tumor tissue (study group) and normal lung tissue (control group) were eligible for this study. The expression of miR-22-3p in the two groups was detected through RT-PCR. Immunohistochemical method was used to detect the expression of VEGF and leukocyte differentiation antigen 31 (CD31) marked microvessel density (MVD) in lung adenocarcinoma. The expressions of matrix metalloproteinase-3 (MMP-3) and matrix metalloproteinase-7 (MMP-7) in lung adenocarcinoma were also detected through the use of Western Blot. RESULTS: The present study revealed significant difference in the expression of miR-22-3p between the two groups. No significant difference in the expression of gender, age, neural invasion and the number of lesions were observed between groups. There was significant difference in the expression of miR-22-3p in the maximum diameter of tumor, pleural recidivism, vascular recidivism, lymph node metastasis and different TNM stages. Based on survival analysis, miR-22-3p was linked to survival time. Correlation analysis indicated that there was negative correlation between miR-22-3p and VEGF, miR-22-3p and MVD, miR-22-3p and MMP-3, and miR-22-3p and MMP-7 in lung adenocarcinoma. CONCLUSION: Our findings provide evidence that miR-22-3p is low expressed in lung adenocarcinoma tissues and the low expression of miR-22-3p is closely associated with clinicopathological characteristics and the prognosis. MiR-22-3p may be involved in the tumor progression of lung adenocarcinoma and may serve as a biomarker for the diagnosis and prognosis of lung adenocarcinoma.

Can dynamic imaging, using 18F-FDG PET/CT and CT perfusion differentiate between benign and malignant pulmonary nodules?

BACKGROUND: The aim of the study was to derive and compare metabolic parameters relating to benign and malignant pulmonary nodules using dynamic 2-deoxy-2-[fluorine-18]fluoro-D-glucose (18F-FDG) PET/CT, and nodule perfusion parameters derived through perfusion computed tomography (CT). PATIENTS AND METHODS: Twenty patients with 21 pulmonary nodules incidentally detected on CT underwent a dynamic 18F-FDG PET/CT and a perfusion CT. The maximum standardized uptake value (SUVmax) was measured on conventional 18F-FDG PET/CT images. The influx constant (Ki ) was calculated from the dynamic 18F-FDG PET/CT data using Patlak model. Arterial flow (AF) using the maximum slope model and blood volume (BV) using the Patlak plot method for each nodule were calculated from the perfusion CT data. All nodules were characterized as malignant or benign based on histopathology or 2 year follow up CT. All parameters were statistically compared between the two groups using the nonparametric Mann-Whitney test. RESULTS: Twelve malignant and 9 benign lung nodules were analysed (median size 20.1 mm, 9-29 mm) in 21 patients (male/female = 11/9; mean age ± SD: 65.3 ± 7.4; age range: 50-76 years). The average SUVmax values ± SD of the benign and malignant nodules were 2.2 ± 1.7 vs. 7.0 ± 4.5, respectively (p = 0.0148). Average Ki values in benign and malignant nodules were 0.0057 ± 0.0071 and 0.0230 ± 0.0155 min-1, respectively (p = 0.0311). Average BV for the benign and malignant nodules were 11.6857 ± 6.7347 and 28.3400 ± 15.9672 ml/100 ml, respectively (p = 0.0250). Average AF for the benign and malignant nodules were 74.4571 ± 89.0321 and 89.200 ± 49.8883 ml/100g/min, respectively (p = 0.1613). CONCLUSIONS: Dynamic 18F-FDG PET/CT and perfusion CT derived blood volume had similar capability to differentiate benign from malignant lung nodules.

HIF-1α promoted vasculogenic mimicry formation in lung adenocarcinoma through NRP1 upregulation in the hypoxic tumor microenvironment.

Neovascularization is a key factor that contributes to tumor metastasis, and vasculogenic mimicry (VM) is an important form of neovascularization found in highly invasive tumors, including lung cancer. Despite the increasing number of studies focusing on VM, the mechanisms underlying VM formation remain unclear. Herein, our study explored the role of the HIF-1α/NRP1 axis in mediating lung adenocarcinoma metastasis and VM formation. HIF-1α, NRP1 expression, and VM in lung adenocarcinoma (LUAD) patient samples were examined by immunohistochemical staining. Quantitative real-time (qRT-PCR), western blot, transwell assay, wound healing assay, and tube formation assay were performed to verify the role of HIF-1α/NRP1 axis in LUAD metastasis and VM formation. ChIP and luciferase reporter assay were used to confirm whether NRP1 is a direct target of HIF-1α. In LUAD tissues, we confirmed a positive relationship between HIF-1α and NRP1 expression. Importantly, high HIF-1α and NRP1 expression and the presence of VM were correlated with poor prognosis. We also found that HIF-1α could induce LUAD cell migration, invasion, and VM formation by regulating NRP1. Moreover, we demonstrated that HIF-1α can directly bind to the NRP1 promoter located between -2009 and -2017 of the promoter. Mechanistically, MMP2, VE-cadherin, and Vimentin expression were affected. HIF-1α plays an important role in inducing lung adenocarcinoma cell metastasis and VM formation via upregulation of NRP1. This study highlights the potential therapeutic value of targeting NRP1 for suppressing lung adenocarcinoma metastasis and progression.

Inhibitory effects of terrein on lung cancer cell metastasis and angiogenesis.

Cancer metastasis is the leading cause of mortality in cancer patients. Over 70% of lung cancer patients are diagnosed at advanced or metastatic stages, and this results in an increased incidence of mortality. Terrein is a secondary bioactive fungal metabolite isolated from Aspergillus terreus. Numerous studies have demonstrated that terrein has anticancer properties, but in the present study, the cellular mechanisms underlying the inhibition of lung cancer cell metastasis by terrein was investigated for the first time. Using MTT assays, the cytotoxic effects of terrein were first examined in human lung cancer cells (A549 cells) and then compared with its cytotoxic effects in three noncancer control cell lines (Vero kidney, L6 skeletal muscle and H9C2 cardiomyoblast cells). The results indicated that terrein significantly reduced the viability of all these cells but exhibited a different level of toxicity in each cell type; these results revealed a specific concentration range in which the effect of terrein was specific to A549 cells. This significant cytotoxic effect of terrein in A549 cells was verified using LDH assays. It was then demonstrated that terrein attenuated the proliferation of A549 cells using IncuCyte image analysis. Regarding its antimetastatic effects, terrein significantly inhibited A549 cell adhesion, migration and invasion. In addition, terrein suppressed the angiogenic processes of A549 cells, including vascular endothelial growth factor (VEGF) secretion, capillary­like tube formation and VEGF/VEGFR2 interaction. These phenomena were accompanied by reduced protein levels of integrins, FAK, and their downstream mediators (e.g., PI3K, AKT, mTORC1 and P70S6K). All these data indicated that terrein was able to inhibit all the major metastatic processes in human lung cancer cells, which is crucial for cancer treatment.

Apelin promotes blood and lymph vessel formation and the growth of melanoma lung metastasis.

Apelin, a ligand of the APJ receptor, is overexpressed in several human cancers and plays an important role in tumor angiogenesis and growth in various experimental systems. We investigated the role of apelin signaling in the malignant behavior of cutaneous melanoma. Murine B16 and human A375 melanoma cell lines were stably transfected with apelin encoding or control vectors. Apelin overexpression significantly increased melanoma cell migration and invasion in vitro, but it had no impact on its proliferation. In our in vivo experiments, apelin significantly increased the number and size of lung metastases of murine melanoma cells. Melanoma cell proliferation rates and lymph and blood microvessel densities were significantly higher in the apelin-overexpressing pulmonary metastases. APJ inhibition by the competitive APJ antagonist MM54 significantly attenuated the in vivo pro-tumorigenic effects of apelin. Additionally, we detected significantly elevated circulating apelin and VEGF levels in patients with melanoma compared to healthy controls. Our results show that apelin promotes blood and lymphatic vascularization and the growth of pulmonary metastases of skin melanoma. Further studies are warranted to validate apelin signaling as a new potential therapeutic target in this malignancy.

The mineral dust-induced gene, mdig, regulates angiogenesis and lymphangiogenesis in lung adenocarcinoma by modulating the expression of VEGF-A/C/D via EGFR and HIF-1α signaling.

Mineral dust­induced gene (mdig) is a novel lung cancer­related oncogene. The aim of this study was to explore the effects of mdig on angiogenesis and lymphangiogenesis by vascular endothelial growth factor (VEGF) in lung adenocarcinoma. mdig­overexpressing A549, H1299 and 293T cells, mdig­silenced A549, human umbilical vein endothelial cells (HUVECs) and human lymphatic endothelial cells (HLECs) were cultured under normoxic and hypoxic conditions. Protein expression levels of mdig, epidermal growth factor receptor (EGFR), phospho(p)­EGFR Tyr1068, hypoxia­inducible factor­1α (HIF­1α), VEGF­A/C/D and VEGF­R1/R2/R3 were assessed using western blotting. mRNA expression levels of mdig, EGFR and HIF­1α were measured using RT­qPCR. Tube formation and xenograft tumor experiments were performed to examine the mechanism of mdig in angiogenesis and lymphangiogenesis. Protein expression levels of EGFR, HIF­1α and VEGF­A/C/D were significantly upregulated in cells cultured under hypoxic conditions compared with those cultured under normoxic conditions, whereas the levels of mdig were decreased. Protein expression levels of EGFR, p­EGFR and VEGF­A/R1/R2 were significantly increased in the mdig­overexpressing cells, whereas the levels of HIF­1α and VEGF­C/D/R3 were decreased compared with those in control cells, all of which were reversed in mdig­silenced cells. Tumor volumes and density of angiogenesis in the mdig­overexpressing group were significantly increased compared with those in the control group, whereas the density of lymphangiogenesis was decreased. No tumors formed in the mdig­silenced group after 3 weeks of assessment in vivo. Protein expression levels of EGFR, p­EGFR, VEGF­A and angiogenesis density were significantly reduced in the mdig­overexpressing cells treated with an EGFR inhibitor, whereas the levels of HIF­1α, VEGF­C/D and the lymphangiogenesis density were significantly increased in mdig­overexpressing cells treated with a HIF­1α agonist. All changes in protein expression were reversed in EGFR agonist and HIF­1α inhibitor treated mdig­silenced cells. In conclusion, mdig is an oxygen­sensitive protein that promotes tumor growth and angiogenesis by activating the EGFR/p­EGFR/VEGF­A/VEGF­R1/R2 pathway and inhibits lymphangiogenesis by blocking the HIF­1α/VEGF­C/D/VEGF­R3 pathway.

Neuritin promotes angiogenesis through inhibition of DLL4/Notch signaling pathway.

Neuritin is a member of the neurotrophic factor family, which plays an important role in the promotion and development of the nervous system. Neuritin is also involved in angiogenesis. Neuritin was recently found to be a negative regulatory factor of the Notch 1 signaling pathway. Notch signaling pathway is known as a regulatory pathway of angiogenesis. Thus, neuritin may play a role in angiogenesis through the Notch signaling pathway. In the present study, we investigated the expressions of neuritin and Notch signaling pathway factors in the pulmonary vascular tissue. The results showed that neuritin expression was increased in the paraneoplastic vascular tissue and decreased in the lung cancer vascular tissue. The neuritin expression was increased with the increase of vascular tissue density, and a negative correlation between neuritin expression and delta-like ligand 4 (DLL4) was identified in vascular tissues of lung cancer. Overexpression of neuritin in human umbilical vein endothelial cells (HUVECs) inhibited the expressions of Notch signaling pathway-associated factors, including DLL4, NICD, and Hes-1, and promoted the migration and tubular formation of HUVECs. In conclusion, our results indicated that neuritin is involved in angiogenesis and may play a role in angiogenesis through the Notch signaling pathway. This study provides a theoretical basis for clinical anti-angiogenesis therapy.