Effects of autocrine vascular endothelial growth factor (VEGF) in non-small cell lung cancer cell line A549

Suppressing VEGF-A/VEGFR-2 Signaling Contributes to the Anti-Angiogenic Effects of PPE8, a Novel Naphthoquinone-Based Compound

Natural naphthoquinones and their derivatives exhibit a broad spectrum of pharmacological activities and have thus attracted much attention in modern drug discovery. However, it remains unclear whether naphthoquinones are potential drug candidates for anti-angiogenic agents. The aim of this study was to evaluate the anti-angiogenic properties of a novel naphthoquinone derivative, PPE8, and explore its underlying mechanisms. Determined by various assays including BrdU, migration, invasion, and tube formation analyses, PPE8 treatment resulted in the reduction of VEGF-A-induced proliferation, migration, and invasion, as well as tube formation in human umbilical vein endothelial cells (HUVECs). We also used an aorta ring sprouting assay, Matrigel plug assay, and immunoblotting analysis to examine PPE8’s ex vivo and in vivo anti-angiogenic activities and its actions on VEGF-A signaling. It has been revealed that PPE8 inhibited VEGF-A-induced micro vessel sprouting and was capable of suppressing angiogenesis in in vivo models. In addition, PPE8 inhibited VEGF receptor (VEGFR)-2, Src, FAK, ERK1/2, or AKT phosphorylation in HUVECs exposed to VEGF-A, and it also showed significant decline in xenograft tumor growth in vivo. Taken together, these observations indicated that PPE8 may target VEGF-A–VEGFR-2 signaling to reduce angiogenesis. It also supports the role of PPE8 as a potential drug candidate for the development of therapeutic agents in the treatment of angiogenesis-related diseases including cancer.

Anti-Angiogenetic and Anti-Lymphangiogenic Effects of a Novel 2-Aminobenzimidazole Derivative, MFB

Background and Purpose

Benzimidazoles have attracted much attention over the last few decades due to their broad-spectrum pharmacological properties. Increasing evidence is showing the potential use of benzimidazoles as anti-angiogenic agents, although the mechanisms that impact angiogenesis remain to be fully defined. In this study, we aim to investigate the anti-angiogenic mechanisms of MFB, a novel 2-aminobenzimidazole derivative, to develop a novel angiogenesis inhibitor.

Experimental Approach

MTT, BrdU, migration and invasion assays, and immunoblotting were employed to examine MFB’s effects on vascular endothelial growth factor (VEGF)-induced endothelial cell proliferation, migration, invasion, as well as signaling molecules activation. The anti-angiogenic effects of MFB were analyzed by tube formation, aorta ring sprouting, and matrigel plug assays. We also used a mouse model of lung metastasis to determine the MFB’s anti-metastatic effects.

Key Results

MFB suppressed cell proliferation, migration, invasion, and endothelial tube formation of VEGF-A-stimulated human umbilical vascular endothelial cells (HUVECs) or VEGF-C-stimulated lymphatic endothelial cells (LECs). MFB suppressed VEGF-A and VEGF-C signaling in HUVECs or LECs. In addition, MFB reduced VEGF-A- or tumor cells-induced neovascularization in vivo. MFB also diminished B16F10 melanoma lung metastasis. The molecular docking results further showed that MFB may bind to VEGFR-2 rather than VEGF-A with high affinity.

Conclusions and Implications

These observations indicated that MFB may target VEGF/VEGFR signaling to suppress angiogenesis and lymphangiogenesis. It also supports the role of MFB as a potential lead in developing novel agents for the treatment of angiogenesis- or lymphangiogenesis-associated diseases and cancer.

Pretreatment to Posttreatment Hypoxia Inducible Factor-1α Ratios as a Potentially Predictive Marker for First-Line Treatment in Nonsmall Cell Lung Cancer Patients without Known Driver Mutations

Background: Hypoxia inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) are key angiogenic regulatory factors. The aim of this study was to identify the most useful prognostic angiogenic factors in advanced nonsmall cell lung cancer (NSCLC) without known driver gene mutations. Methods: Eligible patients were pathologically confirmed to have advanced NSCLC without known driver mutations. All patients were treated with standard first-line chemotherapy ± bevacizumab. Serum concentrations of HIF-1α, VEGF, sVEGFR1, sVEGFR2, and endostatin were measured via enzyme-linked immunosorbent assays (ELISAs) prior to and after two cycles of treatment. Area under the curve (AUC) and optimal cutoff values were calculated by receiver operator characteristic curve (ROC) analyses. The parameters that predicted survival were evaluated by univariate and multivariate Cox proportional hazard analyses. Results: A total of 47 patients were included in this study. HIF-1α levels decreased significantly after treatment in the nonprogressing (partial response/stable disease) patient group (707.94 vs. 355.53 pg/mL, p = 0.002), but increased levels were seen in patients with progressive disease, however, the extent of change did not reach significance (173.70 vs. 416.34 pg/mL, p = 0.078). An HIF-1α ratio of 1.18 was chosen as the best point to predict treatment response through ROC analyses. Via univariate and multivariate analyses, we found that patients with a HIF-1α ratio ≥1.18 after treatment were significantly more likely to have a prolonged progression-free survival (PFS, HR 0.303, 95% CI: 0.153-0.603, p = 0.001) and overall survival (OS, HR 0.436, 95% CI: 0.153-0.603, p = 0.025). Conclusions: We identified the pretreatment to posttreatment HIF-1α ratio as a promising predictor for PFS and OS in NSCLC patients without known driver mutations.

Resveratrol suppresses vascular endothelial growth factor secretion via inhibition of CXC-chemokine receptor 4 expression in ARPE-19 cells

The present study characterizes the effects of resveratrol (Res) on vascular endothelial growth factor (VEGF) secretion in retinal pigment epithelial (RPE) cells. ARPE-19 cells were treated with CoCl2, a hypoxia mimetic agent. CoCl2 treatment increased protein levels of hypoxia inducible factor-1α (HIF-1α) and CXC-chemokine receptor 4 (CXCR4), and secretion of VEGF. To confirm the effects of Res on VEGF secretion, the human umbilical vein endothelial cell tube formation assay was performed with conditioned medium from Res-treated ARPE-19 cells. The well-known antioxidant Res effectively blocked these effects and reduced phosphorylation of nuclear factor (NF)-κB, an upstream activator of CXCR4. Furthermore, Res also suppressed VEGF secretion induced by SDF-1, a ligand of CXCR4. Conditioned medium from Res-treated ARPE-19 cells clearly suppressed tube formation compared with hypoxia-treated conditioned medium. The results demonstrated that Res inhibited the hypoxia mimetic CoCl2-induced expression of VEGF in ARPE-19 cells. Res suppressed CXCR4 expression through decreased phosphorylation of NF-κB, resulting in downregulation of VEGF secretion.

p18, a novel adaptor protein, regulates pulmonary endothelial barrier function via enhanced endocytic recycling of VE-cadherin

Vascular permeability is a hallmark of several disease states including acute lung injury (ALI). Endocytosis of VE-cadherin, away from the interendothelial junction (IEJ), causes acute endothelial barrier permeability. A novel protein, p18, anchors to the endosome membrane and plays a role in late endosomal signaling via MAPK and mammalian target of rapamycin. However, the fate of the VE-cadherin-positive endosome has yet to be elucidated. We sought to elucidate a role for p18 in VE-cadherin trafficking and thus endothelial barrier function, in settings of ALI. Endothelial cell (EC) resistance, whole-cell ELISA, and filtration coefficient were studied in mice or lung ECs overexpressing wild-type or nonendosomal-binding mutant p18, using green fluorescent protein as a control. We demonstrate a protective role for the endocytic protein p18 in endothelial barrier function in settings of ALI in vitro and in vivo, through enhanced recycling of VE-cadherin-positive early endosomes to the IEJ. In settings of LPS-induced ALI, we show that Src tethered to the endosome tyrosine phosphorylates p18 concomitantly with VE-cadherin internalization and pulmonary edema formation. We conclude that p18 regulates pulmonary endothelial barrier function in vitro and in vivo, by enhancing recycling of VE-cadherin-positive endosomes to the IEJ.

Serum tumor markers, hypoxia-inducible factor-1α HIF-1α and vascular endothelial growth factor, in patients with non- small cell lung cancer before and after intervention

OBJECTIVE

To explore changes in the serum tumor makers, hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) level and their relations in patients with non-small cell lung cancer (NSCLC) before and after intervention.

MATERIALS AND METHODS

Forty patients with NSCLC and 40 healthy individuals undergoing physical examination in our hospital provided the observation and control groups. HIF-1α and VEGF levels in serum were detected by enzyme-linked immuno-sorbent assay (ELISA) in the observation group before and after intervention and in control group on the day of physical examination, along with serum carcino-embryonic antigen (CEA), neuron-specific enolase (NSE) and squamous cell carcinoma antigen (SCC) levels in the observation group with a fully automatic biochemical analyzer. Clinical effects and improvement of life quality in the observation group were also evaluated.

RESULTS

The total effective rate and improvement of life quality after treatment in observation group were 30.0% and 32.5%, respectively. Serum HIF-1α and VEGF levels in the control group were lower than that in observation group (p<0.01), but remarkably elevated after intervention (p<0.01). In addition, serum CEA, NSE and SCC levels were apparently lowered by treatment (p<0.01). Serum HIF-1α demonstrated a positive relation with VEGF level (p<0.01) and was inversely related with CEA, NSE and SCC levels (p<0.01).

CONCLUSIONS

Significant correlations exist between marked increase of serum HIF-1α and VEGF levels and decrease of indexes related to hematological tumor markers in NSCLC patients after intervention.

Nonsmall cell lung cancer therapy: insight into multitargeted small-molecule growth factor receptor inhibitors

To date, lung cancer is the leading cause of cancer-related death worldwide, among which nonsmall cell lung cancer (NSCLC) comprises about 85%. Taking into account the side effects of surgery, radiation, platinum-based doublet chemotherapy, and the growth self-sufficiency characteristic of cancer cells, drugs have been discovered toward growth factor receptor (GFR) to treat NSCLC. As expected, these drugs provide a greater benefit. To increase the efficacy of such growth factor receptor tyrosine kinase inhibitors (RTKIs), coinhibition of GFR signaling pathways and combination of inhibitors along with radiation or chemotherapy have drew intense insight. Although clinical trials about single-agent RTKIs or their combination strategies suggest their increase potency against cancer, they are not beyond adverse effects, and sometimes the effects are more deadly than chemotherapy. Nevertheless the hope for RTKIs may be proved true by further researches and digging deep into cancer therapeutics.