The Hippo transducer TAZ confers cancer stem cell-related traits on breast cancer cells

Area of Science:

• Oncology
• Cell Biology
• Molecular Biology

Background:

• Cancer stem cells (CSCs) are crucial for tumor initiation and progression.
• Mechanisms governing CSC properties remain incompletely understood.
• The Hippo pathway regulates cell proliferation and organ size.

Purpose of the Study:

• To investigate the role of TAZ, a Hippo pathway transducer, in breast CSCs.
• To elucidate the molecular mechanisms controlling CSC self-renewal and tumor initiation.
• To link the CSC concept with Hippo pathway signaling in breast cancer.

Main Methods:

• Prospective isolation and characterization of breast CSCs.
• Analysis of TAZ protein levels and activity in CSCs and tumors.
• Investigating TAZ interactions with Scribble and Hippo kinases (MST, LATS).
• Studying the impact of TAZ gain and Scribble loss on CSC properties and EMT.

Main Results:

• TAZ activity is essential for maintaining self-renewal and tumor-initiation in breast CSCs.
• Elevated TAZ levels and activity correlate with CSCs and poorly differentiated tumors, showing prognostic value.
• Acquisition of TAZ confers self-renewal to non-CSCs.
• Scribble loss or EMT induction disrupts TAZ inhibition by Hippo kinases.

Conclusions:

• TAZ is a key regulator of breast CSC self-renewal and tumor initiation.
• The Hippo pathway is mechanistically linked to CSC properties via TAZ.
• Cell polarity, through Scribble, modulates Hippo kinase activity and TAZ function in breast cancer.