p85β phosphoinositide 3-kinase subunit regulates tumor progression

PIK3R2 encodes a ubiquitous regulatory subunit (p85 beta) of PI3K, an enzyme that generates 3-polyphosphoinositides at the plasma membrane. PI3K activation triggers cell survival and migration. We found that p85 beta expression is elevated in breast and colon carcinomas and that its increased expression correlates with PI3K pathway activation and tumor progression. p85 beta expression induced moderate PIP3 generation at the cell membrane and enhanced cell invasion. In accordance, genetic alteration of pik3r2 expression levels modulated tumor progression in vivo. Increased p85 beta expression thus represents a cellular strategy in cancer progression.