Pretreatment of RPE Cells with Lutein Can Mitigate Bevacizumab-Induced Increases in Angiogenin and bFGF

Abstract

Purpose: To determine whether pretreatment of retinal pigmented epithelial (RPE) cells with lutein can affect the response of cells to bevacizumab therapy. Methods: One human RPE cell line (ARPE-19) was used for all experiments. The cells were treated with lutein in different concentrations (0.01, 0.1, 1, 10, or 100 μg/ml). After 24 h, all plates were treated with bevacizumab (0.25 mg/ml). Media were harvested 24 h later for sandwich ELISA-based angiogenesis arrays. A Quantibody Human Angiogenesis Array was used in order to quantify the secretion of the following 10 proangiogenic cytokines: angiogenin, ANG2, EGF, bFGF, HB-EGF, PDGF-BB, leptin, PIGF, HGF and VEGF. Results: Treatment with bevacizumab alone led to a significant decrease in VEGF, as well as a significant increase in angiogenin and bFGF. Pretreatment with 0.1 and 1.0 μg/ml of lutein led to significant decreases in both bFGF and angiogenin following treatment with bevacizumab compared to bevacizumab treatment alone. Lutein alone did not modify the secretion of proangiogenic cytokines. Conclusions: Pretreatment of human RPE cells in culture with specific doses of lutein prior to bevacizumab treatment mitigated the increase in bFGF and angiogenin caused by bevacizumab monotherapy.

anlotinib alters tumor immune microenvironment by downregulating PD-L1 expression on vascular endothelial cells

“…In our study, we found that bevacizumab promoted the PD-L1 expression on VECs. Based on the previous literatures 28,29 and our previous research 30 , we considered that bevacizumab could activate a variety of alternative pathways, such as the FGFR-and TGF-β-signaling pathway when it effectively neutralizes VEGFA, thereby activating the AKT pathway and finally causing upregulation of PD-L1 expression on VECs. In our vitro experiment, (see figure on previous page) Fig.…”

Anlotinib Induces a T Cell–Inflamed Tumor Microenvironment by Facilitating Vessel Normalization and Enhances the Efficacy of PD-1 Checkpoint Blockade in Neuroblastoma

“…Accordingly, the FDA withdrew its approval for breast cancer indications. Several basic studies have found that after effectively inhibiting the activation of the classic VEGFA pathway, the tumor often activates multiple compensatory “bypass activation” pathways, such as the VEGFC ( 34 ), TGF ( 35 ), and FGF ( 36 ) pathways, worsening the biological behavior of tumor cells, as indicated by the invasion of surrounding tissues, the “hijacking” of vessels to support tumor growth ( 37 ), or the occurrence of vasculogenic mimicry to increase the supply of blood and oxygen, rendering drugs targeting vascular ECs useless ( 38 ). The abovementioned bypass activation mechanisms cause the tumor and its blood vessels to rapidly “rebound” and even lead to an increase in tumor invasiveness and metastasis after treatment.…”

Anlotinib Downregulates RGC32 Which Provoked by Bevacizumab

“…Similarly, our recently published studies showed that bevacizumab upregulated TGFβ expression in human endothelial cells, mouse retinal microvascular endothelial cells and mouse brain microvascular endothelial cells ( 17 , 37 ), suggesting that stimulation by higher concentrations of bevacizumab is tangible in several cell lines. Some investigators have shown that FGF upregulates the expression of TGF ( 38 ), bevacizumab upregulates bFGF ( 15 ), and elevated FGF activates AKT signaling to activate RGC32 ( 39 ). TGFβ has also been shown to promote EMT by inducing RGC32 expression via the ERK-MAPK pathway ( 24 , 28 , 29 ).…”

“…A549 cells were first activated with TGF-β, and we confirmed that anlotinib indeed inhibits the downstream P-Smad2 mediation of TGFβ ( Figure 3K ), consistent with inhibition of Smad by anlotinib and upregulation of endoglin (another molecule in TGF-β signaling) by bevacizumab as we have previously reported ( 37 ). Previous studies have shown that anlotinib inhibits FGFR1-4 ( 18 , 19 ), whereas bevacizumab can increase the expression of FGFR ( 15 , 16 ). We believe that anlotinib can downregulate increased RGC32 by inhibiting both FGF/FGFR–AKT and TGFβ/TGFβR-MAPK-ERK pathways ( Figure 7 ).…”

“…Tumor neovascularization is mainly mediated by three signal pathways: the VEGF/VEGFR, fibroblast growth factor (FGF)/fibroblast growth factor receptor (FGFR), and platelet-derived growth factor (PDGF)/platelet-derived growth factor receptor (PDGFR). Bevacizumab can only inhibit VEGF/VEGFR, while FGF/FGFR ( 15 , 16 ) and transforming growth factor-β (TGFβ) are upregulated during the treatment process ( 17 ), which is the probable reason for resistance to bevacizumab. Anlotinib is a multi-target inhibitor that can inhibit VEGFR, FGFR, and PDGFR ( 18 , 19 ).…”