Phosphoinositide 3-kinase p85beta regulates invadopodium formation

Area of Science:

• Cell Biology
• Oncology
• Molecular Biology

Background:

• Tumor progression involves acquiring invasiveness and metastasis.
• The precise mechanisms driving cell invasion remain incompletely understood.
• The role of p85β, a regulatory subunit of phosphoinositide-3-kinase, in invasion is unknown, despite its increased expression in advanced carcinoma.

Purpose of the Study:

• To investigate the potential role of p85β in facilitating cancer cell invasion.
• To elucidate the molecular mechanisms by which p85β might influence cell adhesion and invasion.

Main Methods:

• Immunofluorescence microscopy to observe p85β localization at cell adhesions.
• Analysis of cell adhesion stability and maturation.
• Investigation of F-actin polymerization and the recruitment of Cdc42/Rac at cell adhesions.
• Assessment of p85β levels in metastatic melanoma and the impact of p85β depletion on invadopodium formation and invasion.

Main Results:

• p85β localizes to cell adhesions, enhancing their stability and maturation.
• p85β promotes the formation of F-actin cores at cell adhesions, resembling invadopodia.
• p85β facilitates F-actin polymerization by recruiting active Cdc42/Rac to cell adhesions.
• Elevated p85β levels correlate with melanoma metastasis, and its depletion reduces invadopodium formation and invasion.

Conclusions:

• p85β enhances cancer cell invasion by promoting the development of invadopodia-like structures at cell adhesions.
• These findings explain the metastatic potential observed in tumors with increased p85β expression.
• p85β represents a potential therapeutic target for inhibiting cancer metastasis.