MDK and lung adenocarcinoma: MDK is known to activate not only the PI3K/AKT pathway but also the MAPK pathway in primary neuronal culture [16] and myocardium [28]; however, in our study iMDK inhibited only the PI3K pathway but not the MAPK pathway, and actually activated the MAPK pathway in H441 lung adenocarcinoma cells (Figure S3).