Delta-like 4/Notch pathway is differentially regulated in benign and malignant thyroid tissues

Area of Science:

• Endocrinology
• Oncology
• Molecular Biology

Background:

• Angiogenesis is crucial for embryonic and tumor growth.
• Vascular endothelial growth factor (VEGF) promotes angiogenesis and is elevated in thyroid cancers.
• The Notch signaling pathway's role in thyroid angiogenesis and carcinogenesis is unexplored.

Purpose of the Study:

• To investigate the expression of Notch1, Notch4, and Delta-like 4 (DLL4) in benign and malignant thyroid lesions.
• To determine the role of the Notch pathway in thyroid angiogenesis and cancer.

Main Methods:

• Immunohistochemistry, qRT-PCR, and Western-blot were used to analyze Notch1, Notch4, and DLL4 expression.
• Samples included normal thyroids, Graves' disease, microcarcinomas, papillary carcinomas, and follicular carcinomas.

Main Results:

• Notch1, Notch4, and DLL4 expression was variable in normal and Graves' disease thyroid tissue but homogeneous and intense in carcinomas.
• Quantitative and Western-blot analyses confirmed increased Notch1, Notch4, and DLL4 in carcinomas versus normal tissue.
• DLL4 was detected in capillary endothelial cells in Graves' disease and restricted to large vessels in carcinomas and normal thyroids.

Conclusions:

• Notch1, Notch4, and DLL4 are detected in thyroid cells and regulated in various thyroid pathologies.
• The Notch signaling pathway likely contributes to thyroid carcinogenesis and angiogenesis.