On the basis of the frequent involvement of the Ras-RAF-MEK-ERK signaling pathway in human non-small cell lung carcinoma (NSCLC), we have explored the target cell availability, reversibility, and cell type specificity of transformation by oncogenic C-RAF.
Recent evidence indicates that both the phosphatidylinositol 3-kinase (PI3K)/AKT and the MEK/ERK pathways are strictly regulated by epidermal growth factor receptor in non-small cell lung cancer (NSCLC) that responds to Gefitinib.
Eligible patients were older than 18 years of age; had histologically or cytologically confirmed stage IIIB-IV KRAS-mutant NSCLC; had failed first-line therapy for advanced NSCLC; had WHO performance status of 0-1; had not received previous therapy with either a MEK inhibitor or docetaxel; and had adequate bone marrow, renal, and liver function.
Although several groups have demonstrated that concomitant use of MEK and phosphoinositide 3-kinase (PI3K) inhibitors (MEKi/PI3Ki) can induce dramatic tumor regressions in mouse models of KRAS-mutant non-small cell lung cancer (NSCLC), ongoing clinical trials investigating this strategy have been underwhelming to date.
Our results suggest that prolonged exposure to MEK or ERK inhibitors may not only restrain EMT but also overcome naïve or acquired resistance of NSCLC to EGFR-targeted therapy in the clinic.
Mechanistic studies demonstrated that co-inhibition of EGFR and MEK induced apoptosis and blocked both EGFR-RAS-RAF-MEK-ERK and EGFR-PI3K-AKT-RPS6 nodes simultaneously in RAS-active, but not RAS-inactive NSCLC.
Our data show that combined targeting of MEK and PI3K-AKT with mTOR is a better option than single agents alone for KRAS mutant NSCLC, thus opening the possibility of a beneficial treatment strategy in the future.
This finding suggests that, the combination of a MEK inhibitor with a BRAF inhibitor will be more efficacious in the clinical setting for patients with BRAF mutated NSCLC.
Our findings that both EML4-ALK and mutant EGFR upregulate PD-L1 by activating PI3K-AKT and MEK-ERK signaling pathways in NSCLC reveal a direct link between oncogenic drivers and PD-L1 expression.
Src inhibitors may act with different mechanisms in NSCLCs, depending on EGFR/Ras mutational profile, and may be integrated with EGFR or MEK inhibitors for different cohorts of NSCLCs.
In conclusion, LncRNA BC087858 could promote cells invasion and induce non-T790M mutation acquired resistance to EGFR-TKIs by activating PI3K/AKT and MEK/ERK pathways and EMT via up- regulating ZEB1 and Snail in NSCLC.
Our findings indicate that the MAPK pathway is biologically important for MET-amplified NSCLC and strongly encourage the development of combination therapy with a MET inhibitor and a MEK inhibitor against MET-amplified NSCLC.
Dual inhibition of the HSP90 and MEK signaling pathways with sub-therapeutic doses may represent a potent therapeutic strategy to treat KRAS-mutant NSCLC with intrinsic resistance to MEK inhibition and to resolve the toxicity observed upon dual inhibition of AKT and MEK at therapeutic doses in clinical trials.
Dual MAPK pathway inhibition with BRAF and MEK inhibitors in BRAF(V600E)-mutant NSCLC might improve efficacy over BRAF inhibitor monotherapy based on observations in BRAF(V600)-mutant melanoma.
GDC-0980 and GDC-0973 combined treatment led to significant increases in apoptosis and synergistic reductions in proliferation across the panel of cell lines.This study found that the PI3K/MEK co-targeted inhibition strategy is synergistic in all 3 molecular subtypes of NSCLC investigated.
Preclinical evidence of the activity of MEK inhibitors in KRAS-mutant NSCLC has pushed forward the clinical development of these agents (namely selumetinib and trametinib) in KRAS-mutant NSCLC particularly in combination with other agents.
In mesenchymal-like KRAS-mutant NSCLC, FGFR1 is highly expressed, and MEK inhibition relieves feedback suppression of FGFR1, resulting in reactivation of ERK; suppression of ERK by MEKi/FGFRi combination results in tumor shrinkage.Cancer Discov; 6(7); 754-69.
The present study aimed to elucidate the anticancer effects of PI3K (BKM120) and MEK (PD1056309) inhibitors on NSCLC cell lines with KRAS or EGFR mutations.
There were statistically significant associations between high MEK (<i>P</i> = 0.028) and RAS (<i>P</i> = 0.003) signature scores and <i>KRAS</i> mutation in 50 NSCLC samples.