Gambogic amide inhibits angiogenesis by suppressing VEGF/VEGFR2 in endothelial cells in a TrkA-independent manner

Abstract

Context

Gambogic amide (GA-amide) is a non-peptide molecule that has high affinity for tropomyosin receptor kinase A (TrkA) and possesses robust neurotrophic activity, but its effect on angiogenesis is unclear.

Objective

The study investigates the antiangiogenic effect of GA-amide on endothelial cells (ECs).

Materials and methods

The viability of endothelial cells (ECs) treated with 0.1, 0.15, 0.2, 0.3, 0.4, and 0.5 μM GA-amide for 48 h was detected by MTS assay. Wound healing and angiogenesis assays were performed on cells treated with 0.2 μM GA-amide. Chicken eggs at day 7 post-fertilization were divided into the dimethyl sulfoxide (DMSO), bevacizumab (40 μg), and GA-amide (18.8 and 62.8 ng) groups to assess the antiangiogenic effect for 3 days. mRNA and protein expression in cells treated with 0.1, 0.2, 0.4, 0.8, and 1.2 μM GA-amide for 6 h was detected by qRT-PCR and Western blots, respectively.

Results

GA-amide inhibited HUVEC (IC₅₀ = 0.1269 μM) and NhEC (IC₅₀ = 0.1740 μM) proliferation, induced cell apoptosis, and inhibited the migration and angiogenesis at a relatively safe dose (0.2 μM) in vitro. GA-amide reduced the number of capillaries from 56 ± 14.67 (DMSO) to 20.3 ± 5.12 (62.8 ng) in chick chorioallantoic membrane (CAM) assay. However, inactivation of TrkA couldn’t reverse the antiangiogenic effect of GA-amide. Moreover, GA-amide suppressed the expression of VEGF and VEGFR2, and decreased activation of the AKT/mTOR and PLCγ/Erk1/2 pathways.

Conclusions

Considering the antiangiogenic effect of GA-amide, it might be developed as a useful agent for use in clinical combination therapies.

Keywords:

• Antiangiogenic
• AKT/mTOR
• PLCγ/Erk1/2
• anticancer
• phytochemicals

Disclosure statement

The authors declare that they have no conflicts of interest.

Author contributions

Tongtong Sui designed and performed research, analyzed data, and wrote the paper. Bojun Qiu, Jiaorong Qu, Yuxin Wang, and Kunnian Ran collected data and performed the statistical analysis. Wei Han and Xiaozhong Peng directed the experimental design and data analysis.

Additional information

Funding

This work was supported by the National Sciences Foundation of China (82173373), the Beijing Nova Program of Science and Technology (Z191100001119137), CAMS Innovation Fund for Medical Sciences (CIFMS) grant (2021-1-I2M-034).