mTORC1 shutdown unleashes TFEB to drive triple-negative breast cancer invasion

Area of Science:

• Oncology
• Molecular Biology
• Cell Biology

Background:

• The PI3K/AKT/mTOR pathway is a recognized therapeutic target for triple-negative breast cancer (TNBC).
• Targeting this pathway aims to inhibit cancer cell proliferation and survival.

Purpose of the Study:

• To investigate the effects of mTORC1 inhibition on TNBC progression.
• To explore the role of TFEB activation in response to mTORC1 inhibition.

Main Methods:

• Utilized molecular biology techniques to study the PI3K/AKT/mTOR pathway in TNBC models.
• Assessed the impact of mTORC1 inhibition on TFEB activity, MT1-MMP exocytosis, and extracellular matrix (ECM) degradation.
• Evaluated the combined effects of mTORC1 inhibition and chemotherapy on cell invasion.

Main Results:

• mTORC1 inhibition was found to activate TFEB, a transcription factor.
• Activated TFEB promoted the exocytosis of MT1-MMP, an enzyme involved in ECM degradation.
• Increased ECM degradation led to enhanced cell invasion, especially when combined with chemotherapy.

Conclusions:

• mTORC1 inhibition may paradoxically promote TNBC cell invasion by activating TFEB.
• The findings challenge the current therapeutic strategy of targeting the PI3K/AKT/mTOR pathway in TNBC.
• Further research is needed to understand the complex role of this pathway in TNBC treatment.