Targeting the proteasome as a promising therapeutic strategy in thyroid cancer

Area of Science:

• Oncology
• Molecular Biology
• Cancer Therapy

Background:

• Anaplastic thyroid cancer (ATC) is resistant to conventional treatments.
• Targeting the ubiquitin-proteasome system with proteasome inhibitors offers a novel therapeutic strategy.
• Bortezomib is a proteasome inhibitor with potential anti-cancer applications.

Purpose of the Study:

• To investigate the in vitro effects of bortezomib on thyroid cancer (TC) cell lines.
• To evaluate the in vivo efficacy of bortezomib in inhibiting ATC tumor growth.
• To assess the impact of bortezomib on proliferation, apoptosis, and vascularity in ATC models.

Main Methods:

• Utilized three anaplastic, one follicular, and one papillary TC cell line for in vitro studies.
• Assessed antiproliferative and proapoptotic effects of bortezomib.
• Evaluated tumor growth inhibition, proliferation (Ki67), vascularity (CD31), and apoptosis (caspase-3) in vivo.

Main Results:

• Bortezomib demonstrated significant antiproliferative effects on TC cells in vitro (IC50 4-10 nM).
• In vivo, bortezomib reduced ATC xenograft tumor volume by up to 74% and decreased tumor vascularity by 57%.
• Bortezomib induced cell cycle arrest and increased caspase-3 activity, but NF-κB activity effects were variable.

Conclusions:

• Proteasome inhibition with bortezomib is effective against ATC in vitro and in vivo.
• Bortezomib reduces cancer cell growth, induces apoptosis, and inhibits tumor vascularity.
• Clinical trials of bortezomib for ATC are warranted despite controversial effects on nuclear transcription.