PTEN “meets” DMSO

© 2004 Elsevier Ltd. All rights reserved.The PTEN proteins (PTEN, for phosphatase and tensin homolog deleted on chromosome ten) are a family of multi-specific phosphatases able to use both lipidic and proteic substrates (for recent reviews on their biochemistry and biomedical relevance see, e.g. The most important physiological PTEN substrate is the lipidic second messenger phosphatidylinositol-3,4,5-trisphosphate (PIP3). Thus, PTEN reverts the phosphoinositide-3-kinases (PI3K) phosphorilation of phosphatidylinositol-4,5-bisphosphate (PIP2) to PIP3. As PIP3 activates the serine–threonine kinase Akt, which is involved in anti-apoptosis, proliferation and oncogenesis, its dephosphorylation by PTEN negatively regulates tumorigenesis. Mutations in the PTEN gene in human can lead to sporadic cancers (e.g., glioblastoma, endometrial and prostatic cancers) or to hereditary disorders characterized by multiple hamartomas and increased risk of cancers (Cowden disease, Bannayan-Zonana syndrome and Lhermitte-Duclos disease). PTEN expression is also associated with neuronal differentiation, and G1 phase cell cycle arrest in cell cultures.