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Updated: Jul 11, 2025
In Vivo Imaging and Quantitation of the Host Angiogenic Response in Zebrafish Tumor Xenografts
Published on: August 14, 2019
Tryptanthrin inhibits tumor angiogenesis via Notch/Dll4 signaling pathway in zebrafish
Meimei Lin1, Hengfen Dai2, Lanlan Zheng3
1Department of Pharmacy, Fuqing City Hospital Affiliated to Fujian Medical University, Fuzhou, China.
Background:
Anti-angiogenic pathways are important for inhibiting tumor growth and migration. Tryptanthrin has anticancer properties in vivo but its anti-angiogenesis activities and associated mechanisms remain unclear.
Methods:
The effects of tryptanthrin were investigated in vivo using fluorescent labeling of blood vessels in zebrafish. Fluorescence quantitation was conducted to analyze the level of delta-like ligand 4 (Dll4) gene expression. Transcriptome sequencing and quantitative polymerase chain reaction (qPCR) analyses were performed to explore the molecular mechanisms of anti-tumor angiogenesis.
Results:
Significant anti-tumor effects were observed in all 48-hpf (hours post-fertilization) zebrafish treated with tryptanthrin (P<0.05). The 6-hpf zebrafish were cultured to 48 and 72 hpf following tryptanthrin treatment. It was found that compared with the control groups, the fluorescence area and the number of complete internode vessels reduced significantly following treatment with medium and high concentrations of tryptanthrin (P<0.05). The relative expression of Dll4 in the 48-hpf zebrafish was significantly inhibited only in the high concentration group (P<0.05). qPCR analysis revealed that the levels of Krt18b, desma, Tnnt2c, and Krt4 gene expression were significantly up-regulated in zebrafish following Dll4 overexpression. After Dll4 knockdown, the level of desma and Tnnt2c gene expression was significantly up-regulated.
Conclusions:
Tryptanthrin can inhibit tumor growth in vivo in a concentration-dependent manner by down-regulating Dll4 protein expression, and at the same time up-regulating the level of desma and Tnnt2c gene expression.
Insights
Tryptanthrin inhibits tumor growth in zebrafish by reducing blood vessel formation. This occurs through down-regulating delta-like ligand 4 (Dll4) and up-regulating desma and Tnnt2c gene expression.
Area of Science:
- Molecular Biology
- Pharmacology
- Developmental Biology
Background:
- Anti-angiogenic pathways are crucial for controlling tumor growth and metastasis.
- Tryptanthrin exhibits known anticancer properties, but its anti-angiogenesis effects and mechanisms require further elucidation.
Purpose of the Study:
- To investigate the anti-angiogenesis activity of tryptanthrin in vivo.
- To explore the molecular mechanisms underlying tryptanthrin's anti-tumor angiogenesis effects, focusing on delta-like ligand 4 (Dll4) gene expression.
Main Methods:
- Utilized zebrafish models with fluorescently labeled blood vessels to assess tryptanthrin's effects on angiogenesis.
- Quantified blood vessel formation and analyzed gene expression of Dll4, Krt18b, desma, Tnnt2c, and Krt4 using transcriptome sequencing and qPCR.
Main Results:
- Tryptanthrin demonstrated significant anti-tumor effects in zebrafish in a dose-dependent manner.
- Reduced blood vessel area and internode vessel number were observed with increasing tryptanthrin concentrations.
- High concentrations of tryptanthrin significantly inhibited Dll4 expression, while Dll4 overexpression/knockdown modulated desma and Tnnt2c expression.
Conclusions:
- Tryptanthrin inhibits tumor growth in vivo by down-regulating Dll4 expression, thereby affecting angiogenesis.
- The anti-angiogenic mechanism involves the concurrent upregulation of desma and Tnnt2c gene expression.
