PTEN

Overview

PTEN (Phosphatase and Tensin Homolog) is a dual-specificity tumor suppressor protein encoded by the PTEN gene on chromosome 10q23. It functions primarily as a lipid phosphatase that dephosphorylates phosphatidylinositol (3,4,5)-trisphosphate (PIP3), thereby acting as the principal negative regulator of the PI3K/AKT/mTOR signaling pathway — one of the most frequently dysregulated axes in human cancer. By opposing the activity of PI3-kinase, PTEN limits Akt1 activation and downstream pro-survival and proliferative signaling through the mechanistic target of rapamycin kinase (mTOR). Beyond its cytoplasmic phosphatase function, PTEN is also capable of nuclear translocation, where it participates in DNA damage response, chromosomal stability, and transcriptional regulation. Loss of PTEN function — through deletion, mutation, promoter silencing, or post-translational inhibition — is among the most common molecular alterations in human malignancy, occurring across many tumor types, and is frequently associated with poor prognosis, therapy resistance, and aggressive disease biology.

PTEN's tumor suppressive role extends beyond oncology. It is a critical regulator of neuronal survival, synaptic plasticity, and metabolic homeostasis, and its dysfunction has been implicated in neurodegenerative conditions, cognitive impairment, and metabolic syndromes. Because PTEN sits at the convergence of growth factor signaling, apoptosis, autophagy pathways, and immune regulation, it has emerged as a high-priority node in both basic and translational biomedical research.

Focus of Latest Publications

Recent publications have continued to position PTEN as a central tumor suppressor and signaling node across cancer and noncancer models. In hepatocellular carcinoma, PTEN was linked to oncogenic regulation by CNOT9, where CNOT9 knockdown activated PTEN, inhibited AKT signaling, and reduced proliferation while increasing apoptosis and G2-phase arrest. A separate hepatocellular carcinoma study identified pentagalloylglucose (PGG) as an orally available small-molecule inhibitor that suppresses AP5Z1-mediated ubiquitination and degradation of PTEN, thereby blocking downstream PI3K/AKT/mTOR signaling and reducing tumor growth in vitro and in vivo. PTEN was also implicated in a breast cancer study of androgen receptor agonism, where EP0062 showed antitumor activity in estrogen receptor-positive metastatic breast cancer models, including tumors with PTEN mutations.

Several studies focused on PTEN in the context of therapy resistance and pathway modulation. In pancreatic ductal adenocarcinoma, Aurora kinase A was shown to promote radioresistance by interacting with GSK3β and driving inhibitory phosphorylation of PTEN at T366, which impaired PTEN phosphatase activity and sustained PI3K/AKT/mTOR signaling; this phenotype was reversed by GSK3β knockdown or a PTEN-T366A mutant. In prostate cancer, SHLD2 loss was reported to frequently co-occur with PTEN loss in a subset of tumors, although the enhanced radiosensitization to polymerase theta inhibition plus radiotherapy was independent of PTEN status. A review of metastatic castration-resistant prostate cancer also highlighted protein kinase B inhibitors as a strategy for the PTEN-loss subset.

PTEN was additionally studied in regenerative and delivery-based approaches. In spinal cord injury models, platelet-rich plasma-primed bone marrow mesenchymal stem cell-derived exosomes delivered miR-29a-3p, which targeted PTEN and modulated the PTEN/PI3K/Akt/mTOR axis to inhibit neuronal apoptosis and autophagy while promoting nerve regeneration. In glioblastoma, mannose-cholesterol lipid nanoparticles carrying PTEN mRNA crossed the blood-brain barrier, accumulated preferentially in orthotopic tumors, restored tumor suppression, reduced tumor burden, and extended survival in mice. Another nanoparticle-based study used curcumin-loaded CRISPR-supported polymeric nanoparticles to silence Kras-G12D while increasing PTEN expression in metastatic pulmonary cancer cells.

PTEN also appeared in studies of apoptosis, metastasis, and neurotoxicity. In triple-negative breast cancer cells, betulinic acid and doxorubicin were associated with miR-21 downregulation and increased PTEN expression, alongside apoptosis and growth arrest. In another breast cancer study, Otostegia fruticosa treatment altered PTEN expression together with p-Akt, caspase-related markers, and metastasis-associated proteins, consistent with reduced invasion and migration. Outside oncology, ERα agonism was investigated in aged female mice exposed to sevoflurane, with PTEN nuclear translocation proposed as a mediator of hippocampal synaptic and cognitive deficits.