Phosphatase and tensin homologue deleted on chromosome ten (PTEN) as a molecular target in lung epithelial wound repair.
OBJECTIVE
Epithelial injury contributes to lung pathogenesis. Our work and that of others have identified the phosphoinositide-3 kinase (PI3K)/Akt pathway as a vital component of survival in lung epithelia. Therefore, we hypothesized that pharmacological inhibition of PTEN, a major suppressor of this pathway, would enhance wound closure and restore lung epithelial monolayer integrity following injury.


METHODS
We evaluated the ability of two bisperoxovanadium derivatives, bpV(phen) and bpV(pic), in differentiated primary human airway epithelia and BEAS2B cultures for their ability to inhibit PTEN, activate the PI3K/Akt pathway and restore epithelial monolayer integrity following mechanical injury.


RESULTS
BpV(phen) and bpV(pic) induced Akt phosphorylation in primary and BEAS2B cells in a dose and time dependent manner. Minimal toxicity was observed as measured by lactate dehydrogenase (LDH) release. To verify that Akt phosphorylation is specifically induced by PTEN inhibition, the PTEN positive cell line, DU145, and two PTEN negative cell lines, LNCaP and PC3, were examined. PTEN positive cells demonstrated a dose responsive increase in Akt phosphorylation whereas PTEN negative cells showed no response indicating that bpV(phen) directly suppresses PTEN without affecting auxiliary pathways. Next, we observed that exposure to either compound resulted in accelerated wound closure following mechanical injury. Similar effects were observed after transfection with a dominant negative isoform of PTEN and PTEN specific siRNA.


CONCLUSIONS
From these studies, we conclude that PTEN is a valid target for future studies directed at restoring epithelial barrier function after lung injury.
Lai
J-P
JP
The Davis Heart and Lung Research Institute, Department of Internal Medicine, The Ohio State University, Columbus, OH 43210, USA.
Dalton
J T
JT
Knoell
D L
DL
D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D016503:Drug Delivery Systems; D004847:Epithelial Cells / Q000187:drug effects / Q000473:pathology; D005952:Glucose-6-Phosphatase / Q000037:antagonists & inhibitors; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000187:drug effects / Q000378:metabolism; D008168:Lung / Q000166:cytology / Q000187:drug effects / Q000473:pathology; D009942:Organometallic Compounds / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D051059:PTEN Phosphohydrolase / Q000187:drug effects*; D010618:Phenanthrolines / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D019869:Phosphatidylinositol 3-Kinases / Q000187:drug effects / Q000378:metabolism; D010766:Phosphorylation; D017027:Protein Tyrosine Phosphatases / Q000037:antagonists & inhibitors; D051057:Proto-Oncogene Proteins c-akt / Q000187:drug effects / Q000378:metabolism; D015398:Signal Transduction; D013997:Time Factors; D014945:Wound Healing / Q000187:drug effects* / Q000502:physiology
D009942:Organometallic Compounds; D010618:Phenanthrolines; C119540:oxodiperoxo(pyridine-2-carboxylate)vanadate(V); C102120:bisperoxo(1,10-phenanthroline)oxovanadate(1-); D007770:L-Lactate Dehydrogenase; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D017027:Protein Tyrosine Phosphatases; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human; D005952:Glucose-6-Phosphatase