Figure 2.

Scheme showing the possible oncogenic signaling pathways involved in the stimulation of sustained growth, survival, migration, invasion, and drug resistance of PC cells. The intracellular signal transducing elements and expression of target gene products induced through the activation of EGFR family members, sonic hedgehog (SHH/PTCH/GLI), Wnt/β-catenin, and SCF-1/CXCR4 pathways and possible cross-talks between these cascades are shown. Moreover, the chemotherapeutic drug efflux mediated through the ABC-multidrug transporters such as ABCG2 pump is also illustrated. BCRP-1/ABCG2, Breast cancer resistance protein-1; CDK, cyclin-dependent kinase; LRP, low-density lipoprotein receptor-related protein; MEK, extracellular signal-related kinase kinase; MMPs, matrix metalloproteinases; PLC-γ, phospholipase C-γ; PTCH, hedgehog-patched receptor; SHH, sonic hedgehog ligand; uPA, urokinase plasminogen activator; Wnt, wingless ligand.