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Epidermal growth factor receptor endocytic traffic perturbation by phosphatidate phosphohydrolase inhibition: new strategy against cancer
Author(s) -
Shaughnessy Ronan,
Retamal Claudio,
Oyanadel Claudia,
Norambuena Andrés,
López Alejandro,
BravoZehnder Marcela,
Montecino Fabian J.,
Metz Claudia,
Soza Andrea,
González Alfonso
Publication year - 2014
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/febs.12770
Subject(s) - endocytic cycle , epidermal growth factor receptor , endosome , egfr inhibitors , microbiology and biotechnology , erbb3 , cancer research , epidermal growth factor , endocytosis , receptor tyrosine kinase , biology , protein kinase b , tyrosine kinase , gefitinib , growth inhibition , chemistry , cell growth , signal transduction , receptor , biochemistry , intracellular
Epidermal growth factor receptor ( EGFR ) exaggerated (oncogenic) function is currently targeted in cancer treatment with drugs that block receptor ligand binding or tyrosine kinase activity. Because endocytic trafficking is a crucial regulator of EGFR function, its pharmacological perturbation might provide a new anti‐tumoral strategy. Inhibition of phosphatidic acid ( PA ) phosphohydrolase ( PAP ) activity has been shown to trigger PA signaling towards type 4 phosphodiesterase ( PDE 4) activation and protein kinase A inhibition, leading to internalization of empty/inactive EGFR . Here, we used propranolol, its l ‐ and d ‐ isomers and desipramine as PAP inhibitors to further explore the effects of PAP inhibition on EGFR endocytic trafficking and its consequences on EGFR ‐dependent cancer cell line models. PAP inhibition not only made EGFR inaccessible to stimuli but also prolonged the signaling lifetime of ligand‐activated EGFR in recycling endosomes. Strikingly, such endocytic perturbations applied in acute/intermittent PAP inhibitor treatments selectively impaired cell proliferation/viability sustained by an exaggerated EGFR function. Phospholipase D inhibition with FIPI (5‐fluoro‐2‐indolyl des‐chlorohalopemide) and PDE 4 inhibition with rolipram abrogated both the anti‐tumoral and endocytic effects of PAP inhibition. Prolonged treatments with a low concentration of PAP inhibitors, although without detectable endocytic effects, still counteracted cell proliferation, induced apoptosis and decreased anchorage‐independent growth of cells bearing EGFR oncogenic influences. Overall, our results show that PAP inhibitors can counteract EGFR oncogenic traits, including receptor overexpression or activating mutations resistant to current tyrosine kinase inhibitors, perturbing EGFR endocytic trafficking and perhaps other as yet unknown processes, depending on treatment conditions. This puts PAP activity forward as a new suitable target against EGFR ‐driven malignancy.