Targeting the MAPK Pathway in Cancer

The mitogen-activated protein kinase (MAPK) signaling cascade is fundamental in regulating cellular proliferation and differentiation, cell survival and cell death via apoptosis. Disruption of the MAPK signaling cascade at any point can lead to the evasion of apoptosis and unchecked cell growth and proliferation, leading to oncogenesis. This narrative review describes MAPK pathway dysregulation, its therapeutic targets, and resistance mechanisms. The therapeutic targeting of the MAPK pathway is complex due to the dual context-dependent roles of several kinases in the signaling cascade. Despite the therapeutic effectiveness of MAPK inhibitors, cancer cells develop chemoresistance that needs to be targeted via bypassing (c-Jun N-terminal kinases) JNK, protein kinase AKT and (mammalian target of rapamycin) mTOR signaling cascades, pairing MAPK inhibitors with multiple immune agents and targeting the MAPK pathway downstream of (extracellular signal-regulated kinase) ERK to prevent its reactivation mechanisms using combination therapies, downstream signaling regulators and (Proteolysis Targeting Chimeras) PROTACs. Additionally, MAPK-mediated regulation of ferroptosis is a novel oncological therapeutic targeting strategy for controlling tumor progression. The inhibition of the RAF/MAPK pathway results in alteration of several key regulators of ferroptosis, including SLCA11, GSH, GPX4 and NCO4A, hence affecting lipid cellular iron concentration and lipid peroxidation. Emerging therapies targeting the MAPK pathway should be designed considering crosstalk, compensatory signaling mechanism activation, the role of ferroptosis and the impact of the tumor microenvironment.