DIRAS3 Inhibits Ovarian Cancer Cell Growth by Blocking the Fibronectin-Mediated Integrin β1/FAK/AKT Signaling...

Area of Science:

• Cellular Biology
• Cancer Research
• Molecular Oncology

Background:

• Autophagy is vital for cellular homeostasis and plays a dual role in cancer.
• The tumor suppressor gene DIRAS3 promotes autophagic cell death in ovarian cancer.
• Extracellular matrix (ECM) components can interfere with DIRAS3-mediated anti-cancer effects.

Purpose of the Study:

• To investigate the role of fibronectin (FN) in modulating DIRAS3-induced autophagic cell death in ovarian cancer.
• To explore the underlying molecular mechanisms involving FAK and AKT signaling pathways.

Main Methods:

• Ovarian cancer cell lines were treated with DIRAS3 and/or fibronectin.
• Western blotting was used to assess levels of phosphorylated FAK (p-FAK) and AKT (p-AKT).
• In vivo xenograft models were utilized to evaluate tumor regression upon combined DIRAS3 and defactinib treatment.

Main Results:

• Fibronectin inhibited DIRAS3-induced autophagy and conferred partial resistance to cell death.
• FN treatment reduced the inhibition of p-FAK and p-AKT by DIRAS3.
• Defactinib, a FAK inhibitor, enhanced DIRAS3-induced autophagy and cell death.
• Co-treatment with DIRAS3 and defactinib led to significant tumor regression in vivo.

Conclusions:

• ECM components like fibronectin promote ovarian cancer cell survival by activating β1 integrin, FAK, and AKT pathways, which counteract DIRAS3-induced autophagic cell death.
• Targeting FAK in combination with DIRAS3 re-expression represents a promising therapeutic strategy for ovarian cancer.