Akt isoform-specific effects on thyroid cancer development and progression in a murine thyroid cancer model

Area of Science:

• Oncology
• Molecular Biology
• Genetics

Background:

• Follicular thyroid cancer (FTC) is driven by PI3K/Akt signaling.
• Akt isoforms have specific roles, but in vivo data in FTC are limited.
• Thyroid hormone receptor β (PV) mice develop FTC-like metastatic cancer.

Purpose of the Study:

• To investigate the specific roles of Akt isoforms (Akt1, Akt2, Akt3) in FTC progression.
• To determine how Akt isoform loss affects tumor development, invasion, and metastasis in the PV mouse model.

Main Methods:

• Akt1, Akt2, and Akt3 knockout mice were crossed with PV mice.
• Thyroid size, cancer development, local invasion, and lung metastasis were assessed over 12 months.
• Primary thyrocytes underwent cell motility assays, and thyroid RNA was analyzed via microarray.

Main Results:

• Akt isoform loss reduced overall thyroid size.
• Akt1 knockout specifically delayed tumor development, local invasion, and reduced cell motility.
• Loss of any Akt isoform reduced lung metastasis; Akt1 or Akt3 loss reduced vascular invasion.
• Microarray revealed distinct gene expression changes, with CD209a (dendritic cell marker) upregulated only in Akt1 knockout thyroids.

Conclusions:

• Akt isoforms play both overlapping and distinct roles in FTC progression and metastasis.
• Akt1 appears to be a key regulator of local tumor growth and invasion in this FTC model.
• Targeting specific Akt isoforms may offer differential therapeutic strategies for FTC.