title: p38 Mitogen-activated protein kinase mediates cell death and p21-activated kinase mediates cell survival during chemotherapeutic drug-induced mitotic arrest.
abstract: Activation of the mitotic checkpoint by chemotherapeutic drugs such as taxol causes mammalian cells to arrest in mitosis and then undergo apoptosis. However, the biochemical basis of chemotherapeutic drug-induced cell death is unclear. Herein, we provide new evidence that both cell survival and cell death-signaling pathways are concomitantly activated during mitotic arrest by microtubule-interfering drugs. Treatment of HeLa cells with chemotherapeutic drugs activated both p38 mitogen-activated protein kinase (MAPK) and p21-activated kinase (PAK). p38 MAPK was necessary for chemotherapeutic drug-induced cell death because the p38 MAPK inhibitors SB203580 or SB202190 suppressed cell death. Dominant-active MKK6, a direct activator of p38 MAPK, also induced cell death by stimulating translocation of Bax from the cytosol to the mitochondria in a p38 MAPK-dependent manner. Dominant active PAK suppressed this MKK6-induced cell death. PAK seems to mediate cell survival by phosphorylating Bad, and inhibition of PAK in mitotically arrested cells reduced Bad phosphorylation and increased apoptosis. Our results suggest that therapeutic strategies that suppress PAK-mediated survival signals may improve the efficacy of current cancer chemotherapies by enhancing p38 MAPK-mediated cell death.
authors.affiliation: Department of Cell Physiology and Pharmacology, University of Leicester, United Kingdom.
authors.forename: Karl
authors.initials: K
authors.lastname: Deacon
authors.forename: Pratibha
authors.initials: P
authors.lastname: Mistry
authors.forename: Jonathan
authors.initials: J
authors.lastname: Chernoff
authors.forename: Jonathan L
authors.initials: JL
authors.lastname: Blank
authors.forename: Rajnikant
authors.initials: R
authors.lastname: Patel
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects*; D003593:Cytoplasm / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008928:Mitochondria / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000187:drug effects*; D008938:Mitosis / Q000187:drug effects*; D015739:Nocodazole / Q000494:pharmacology*; D017346:Protein Serine-Threonine Kinases / Q000187:drug effects*; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D054462:p21-Activated Kinases; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D000970:Antineoplastic Agents; C494826:BAX protein, human; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D017346:Protein Serine-Threonine Kinases; D054462:p21-Activated Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D015739:Nocodazole