HDAC6 inhibitor WT161 downregulates growth factor receptors in breast cancer

Area of Science:

• Oncology
• Molecular Biology
• Pharmacology

Background:

• Histone deacetylase 6 (HDAC6) inhibitor WT-161 shows anti-tumor activity in multiple myeloma.
• The efficacy of WT-161 in other cancer types, particularly breast cancer, remains largely unexplored.

Purpose of the Study:

• To investigate the anti-cancer effects of WT-161 in breast cancer cell lines.
• To elucidate the mechanisms underlying WT-161's action in breast cancer.
• To evaluate WT-161's therapeutic potential in combination with existing treatments.

Main Methods:

• Treatment of breast cancer cell lines (MCF7, T47D, BT474, MDA-MB231) with WT-161.
• Assessment of cell viability, apoptosis, and receptor expression (EGFR, HER2, ERα).
• HDAC6 knockdown experiments and use of a non-HDAC inhibitory analog (MAZ1793).
• In vivo efficacy studies using a murine xenograft model with MCF7 cells.
• Combination therapy studies with bortezomib.

Main Results:

• WT-161 induced apoptotic cell death and inhibited growth in multiple breast cancer cell lines.
• WT-161 decreased the expression of EGFR, HER2, and ERα, independent of HDAC6 inhibition.
• WT-161 demonstrated in vivo efficacy in inhibiting MCF7 tumor growth.
• WT-161 synergistically enhanced bortezomib-induced cytotoxicity, including in bortezomib-resistant cells.

Conclusions:

• WT-161 exhibits potent anti-cancer activity in breast cancer through mechanisms not solely dependent on HDAC6 inhibition.
• WT-161 holds potential as a therapeutic agent for breast cancer, including resistant forms.
• These findings support the development of novel therapeutic agents targeting key growth pathways in breast cancer.