Cotransfection of the constitutively active mutant Rac-1 (Val12), an upstream activator of JNK, abrogated Deltap85-induced lung cancer cell death, whereas constitutively active mutant mitogen-activated protein kinase kinase (MKK)-1 (R4F) did not.
Recently, mutations in PIK3CA, a member of the family of phosphatidylinositol 3'-kinase catalytic subunits, were identified in a significant fraction (25-30%) of colorectal cancers, gastric cancers, and glioblastomas and in a smaller fraction of breast and lung cancers.
We detected PIK3CA somatic mutations in 26 of 73 hepatocellular carcinomas (35.6%), 25 of 93 breast carcinomas (26.9%), 12 of 185 gastric carcinomas (6.5%), one of 88 acute leukemias (1.1%), and three of 229 non-small-cell lung cancers (1.3%).
In contrast to HER2-amplified breast cancers, we found that PI3K-mTOR inhibition did not promote substantial apoptosis in the EGFR mutant lung cancers.
This finding set the stage for further testing of FLJ10540 as a new therapeutic target for treating lung cancer and may contribute to the development of new therapeutic strategies that are able to block the PI3K/AKT pathway in lung cancer cells.
Activation to a large extent of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway and mutations in the p53 gene are involved in lung cancer therapeutic resistance.
cIAP2 upregulated by E6 via EGFR/PI3K/AKT cascades may contribute to cisplatin resistance, revealing that the EGFR or PI3K inhibitor combined with cisplatin may improve the chemotherapeutic efficacy in HPV-infected lung cancer.
Furthermore, possible interplay between PI3K/Akt/mTOR pathway activation/inhibition and RhoGDI2 signalling is examined in lung cancer-related cell lines.
Our work further suggests that additional lung cancer chemoprevention trials either targeting the PI3K pathway or measuring airway PI3K activation as an intermediate endpoint are warranted.
The increased TxA(2) may then activate CREB through PI3K/Akt and extracellular ERK pathways, thereby contributing to the NNK-promoted survival and growth of lung cancer cells.
Moreover, previous studies have shown that Pg extracts decrease inflammation in lung cancer cell lines by inhibiting phosphatidylinositol-3,4,5-trisphosphate (PI3K)-dependent phosphorylation of AKT in vitro and inhibiting the activation of NF-kB in vivo.