Harmine suppresses hyper-activated Ras-MAPK pathway by selectively targeting oncogenic mutated Ras/Raf in.
Cancer Cell Int. 2019 ;19:159. Epub 2019 Jun 11. PMID: 31198408
Background: Mutationally activated Ras proteins are closely linked to a wide variety of human cancers. Hence, there has been an intensive search for anti-Ras therapies for cancer treatment. The sole Ras gene, which encodes LET-60, inregulates vulval development. While the loss of-function leads to failure of vulva formation, the-() allele, which contains a missense mutation mimicking a Ras codon 13 mutation found in human cancers, results in extra vulval tissue, a phenotype named Muv (multiple vulvas).
Methods: By taking advantage of the easy-to-score Muv phenotype of-(), we used a step-by-step screening approach (from crude extract to active fraction to active natural compound) to search for inhibitors of oncogenic Ras. Mutants of other key components in the Ras-mitogen-activated protein kinase (MAPK) pathway were used to identify other candidate targets.
Results: The natural compound harmine, isolated from the plant, was found to suppress the Muv phenotype of-(). In addition, harmine targets the hyper-activation of the Ras/MAPK pathway specifically caused by overexpression or mutated forms of LET-60/Ras and its immediate downstream molecule LIN-45/Raf. Finally, harmine can be absorbed into the worm body and probably functions in its native form, rather than requiring metabolic activation.
Conclusion: In sum, we have revealed for the first time the anti-Ras activity of harmine in amodel system. Our results revealed the potential anti-cancer mechanism of harmine, which may be useful for the treatment of specific human cancers that are associated with oncogenic Ras mutations.