Integrin αvβ3-dependent thyroid hormone effects on tumour proliferation and vascularisation

Area of Science:

• Endocrinology
• Oncology
• Molecular Biology

Background:

• Thyroid hormones regulate crucial cellular processes, including tumor growth and progression.
• Integrin αvβ3 is a cell surface receptor implicated in tumor development and found on various cancer-associated cells.

Purpose of the Study:

• To investigate the role of thyroid hormone signaling through integrin αvβ3 in tumor growth.
• To compare the effects of thyroid hormones versus a specific integrin αvβ3 inhibitor (tetrac) on tumor xenografts.

Main Methods:

• Utilized two murine xenograft models: integrin αvβ3-positive SW1736 (anaplastic thyroid cancer) and integrin αvβ3-negative HuH7 (hepatocellular carcinoma).
• Monitored tumor growth, survival, proliferation (Ki67), vascularization (CD31), and apoptosis in euthyroid, hyperthyroid, hypothyroid, and tetrac-treated mice.

Main Results:

• In SW1736 xenografts, hyperthyroidism increased tumor growth and decreased survival; hypothyroidism and tetrac treatment reduced growth and prolonged survival.
• Tumor proliferation and vascularization were elevated in hyperthyroid SW1736 models compared to hypothyroid or tetrac-treated groups.
• No significant differences in tumor growth or proliferation were observed in integrin αvβ3-negative HuH7 xenografts across groups, though vascularization was reduced in hypothyroid and tetrac-treated mice.

Conclusions:

• Thyroid hormone action via integrin αvβ3 significantly influences the growth of αvβ3-positive tumors.
• These findings have implications for managing cancer patients with thyroid dysfunction or those on thyrotropin-suppressive therapy.