Aerosol delivery of glucosylated polyethylenimine/phosphatase and tensin homologue deleted on chromosome 10 complex suppresses Akt downstream pathways in the lung of K-ras null mice.
Difficulties in achieving long-term survival of lung cancer patients treated with conventional therapies suggest that novel approaches are required. Although several genes have been investigated for antitumor activities using gene delivery, problems surrounding the methods used such as efficiency, specificity, and toxicity hinder its application as an effective therapy. This has lead to the re-emergence of aerosol gene delivery as a noninvasive approach to lung cancer therapy. In this study, glucosylated conjugated polyethylenimine (glucosylated PEI) was used as carrier. After confirming the efficiency of glucosylated PEI carriers in lungs, the potential effects of the phosphatase and tensin homologue deleted on chromosome 10 (PTEN) tumor suppressor gene on Akt downstream pathways were investigated. Aerosol containing glucosylated PEI and recombinant plasmid pcDNA3.0-PTEN complex was delivered into K-ras null lung cancer model mice through a nose-only inhalation system. Investigation of proteins in the phosphatidylinositol 3'-kinase/Akt signaling pathway in PTEN-delivered mouse lung revealed that the PTEN protein was highly expressed, whereas the protein levels of PDK1, total Akt1, phospho-(Thr-308)-Akt, phospho-(Ser-2448)-mTOR, p70S6K, and 4E-BP1 were decreased to varying degrees. Additionally, the kinase activities of both Akt and mTOR were suppressed. Finally, apoptosis was detected in PTEN-delivered mouse lung by terminal deoxynucleotidyltransferase-mediated nick end labeling assay, suggesting that our aerosol PTEN delivery is capable of functionally altering cell phenotype in vivo. In summary, Western blot analysis, kinase assays, immunohistochemistry, and terminal deoxynucleotidyltransferase-mediated nick end labeling assays suggest that our aerosol gene delivery technique is compatible with in vivo gene delivery and can be applied as a noninvasive gene therapy.
Kim
Hyun Woo
HW
Laboratory of Toxicology, College of Veterinary Medicine and School of Agricultural Biotechnology, Seoul National University, Seoul, Korea.
Park
In Kyu
IK
Cho
Chong Su
CS
Lee
Kee Ho
KH
Beck
George R
GR
Colburn
Nancy H
NH
Cho
Myung Haing
MH
D000336:Aerosols; D000818:Animals; D011905:Genes, ras / Q000502:physiology*; D015316:Genetic Therapy; D006031:Glycosylation; D007150:Immunohistochemistry; D008168:Lung / Q000378:metabolism; D008175:Lung Neoplasms / Q000628:therapy*; D008297:Male; D051379:Mice; D051059:PTEN Phosphohydrolase; D011094:Polyethyleneimine / Q000008:administration & dosage*; D011494:Protein Kinases / Q000032:analysis; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors*; D017027:Protein Tyrosine Phosphatases / Q000235:genetics*; D011518:Proto-Oncogene Proteins / Q000037:antagonists & inhibitors*; D051057:Proto-Oncogene Proteins c-akt; D015398:Signal Transduction / Q000502:physiology*; D058570:TOR Serine-Threonine Kinases; D025521:Tumor Suppressor Proteins / Q000235:genetics*
D000336:Aerosols; D011518:Proto-Oncogene Proteins; D025521:Tumor Suppressor Proteins; D011094:Polyethyleneimine; D011494:Protein Kinases; C546843:mTOR protein, mouse; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D058570:TOR Serine-Threonine Kinases; D017027:Protein Tyrosine Phosphatases; D051059:PTEN Phosphohydrolase; C487757:Pten protein, mouse