Thus, in addition to EGFR mutations, other factors in NSCLC cells, such as high expression of ErbB family members, may constitutively activate AKT and sensitize cells to EGFR inhibitors.
NSCLC cell lines were treated with the EGFR tyrosine kinase inhibitor (TKI) gefitinib and PD16,8393, the AKT inhibitor SH-6 and LY294002, the farnesyltransferase inhibitor L744832, and the mTOR inhibitor rapamycin.
6-Shogaol, an active constituent of dietary ginger, induces autophagy by inhibiting the AKT/mTOR pathway in human non-small cell lung cancer A549 cells.
Exposure of human NSCLC cell lines to gemcitabine increased the phosphorylation levels of mitogen-activated protein kinase kinase (MKK) 1/2-extracellular signal-regulated kinase (ERK) 1/2 and AKT in a time- and dose-dependent manner, which was accompanied by an induction of Rad51 mRNA and protein expression.
Mutations of EGFR, ERBB2, ERBB3, ERBB4, KRAS, NRAS, BRAF, PTEN, PIK3CA, LKB1, and AKT1 genes were determined by direct sequencing in 173 surgically resected NSCLCs--56 squamous cell carcinomas (SCCs) and 117 adenocarcinomas (ACs).
AKT1-SNP4 association with survival was also evaluated in 127 chemotherapy-treated/gefitinib-naive patients, whereas its relationship with AKT1 expression and gefitinib cytotoxicity was studied in 15 NSCLC cell lines.
These results indicate that EGFR inhibitors enhanced AdTRAIL anti-tumor activity in NSCLC cell lines and that inhibiting the AKT pathway played an important role in this enhancement.
These findings may aid in refining targeted strategies for the inhibition of AKT isoforms towards the sensitization of NSCLC cells to therapeutic agents.
The current study provides evidence that genetic variations within the PI3K/PTEN/AKT/mTOR signaling pathway are associated with variation in clinical outcomes of NSCLC patients.
Breast cancer metastases showed significantly (p < 0.05) higher activation of the c-ERBB2/IGFR-AKT pathway network compared to NSCLC metastases, whereas NSCLC metastases to the brain exhibited higher relative levels of many members of the EGFR-ERK signaling network.
Our studies focus on non-small cell lung cancer (NSCLC) lines, which show phosphatidylinositol 3-kinase (PI3K)/AKT activation secondary to a mutation in the K-Ras gene or the EGFR gene.
These results thus indicate that persistent activation of signaling by the AKT-survivin pathway induced by PTEN loss underlies a mechanism of resistance to erlotinib-induced apoptosis in EGFR mutation-positive NSCLC.
An important role in NSCLC malignancy is attributed to the signal transduction pathways involving PI3Kinase, with consequent activation of the AKT family factors.