title: Long-term activation of SAPK/JNK, p38 kinase and fas-L expression by cisplatin is attenuated in human carcinoma cells that acquired drug resistance.
abstract: Tumor cells chronically exposed to cisplatin (cDDP) acquire cDDP resistance that impacts tumor therapy. To elucidate the mechanism of acquired cDDP resistance (ACR), we compared HeLa cells that gained ACR upon chronic cDDP treatment with the parental strain. We show that ACR is due to a lower level of induced apoptosis. Further, upon cDDP treatment, the levels of Fas, Bax and Bid remained unchanged, whereas Bcl-2 and p-Bad were reduced at late times (120 hr) after treatment. At early times, Fas ligand (fas-L) expression was significantly enhanced in sensitive compared to resistant cells and remained upregulated up to the onset of apoptosis. Thus, activation of the Fas system is critical, which is in line with the finding that in sensitive cells, caspase-8 along with caspase-9 and -3 were activated by cDDP. cDDP provoked the activation of stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK) and p38 kinase dose-dependently, with significantly lower levels in ACR cells than in the sensitive parental line. cDDP induces c-Jun and AP-1 activity, as measured by a reporter gene assay, which was again attenuated in ACR cells. Time course analysis revealed that SAPK/JNK and p38 kinase activity was sustained upregulated (> 72 hr postexposure), which occurred at much higher level in sensitive than in ACR cells. Inhibition of either JNK or p38 kinase (by JNK inhibitor II and SB 203580, respectively) attenuated cDDP-induced apoptosis, supporting the role of JNK and p38 kinase in the cDDP response. Since several independently derived cDDP-resistant cell lines displayed attenuated MAPK signaling, sustained SAPK/JNK and p38 kinase activation may be a general mechanism of cDDP-induced cell death. ACR cells displayed a reduced level of DNA damage, indicating long-term stimulation of SAPK/JNK and p38 kinase is triggered by nonrepaired cDDP-induced DNA lesions.
authors.affiliation: Division of Applied Toxicology, Institute of Toxicology, Mainz, Germany.
authors.forename: Anamaria
authors.initials: A
authors.lastname: Brozovic
authors.forename: Gerhard
authors.initials: G
authors.lastname: Fritz
authors.forename: Markus
authors.initials: M
authors.lastname: Christmann
authors.forename: Jochen
authors.initials: J
authors.lastname: Zisowsky
authors.forename: Ulrich
authors.initials: U
authors.lastname: Jaehde
authors.forename: Maja
authors.initials: M
authors.lastname: Osmak
authors.forename: Bernd
authors.initials: B
authors.lastname: Kaina
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D002277:Carcinoma / Q000188:drug therapy / Q000378:metabolism; D002945:Cisplatin / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D019008:Drug Resistance, Neoplasm; D053222:Fas Ligand Protein; D005260:Female; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D017930:Genes, Reporter; D006367:HeLa Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000187:drug effects* / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000187:drug effects* / Q000378:metabolism; D048055:Mitogen-Activated Protein Kinase 8 / Q000187:drug effects* / Q000378:metabolism; D012334:RNA, Neoplasm / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D015854:Up-Regulation / Q000187:drug effects; D002583:Uterine Cervical Neoplasms / Q000188:drug therapy / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000187:drug effects* / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D008562:Membrane Glycoproteins; D012334:RNA, Neoplasm; D048031:JNK Mitogen-Activated Protein Kinases; D048055:Mitogen-Activated Protein Kinase 8; D048051:p38 Mitogen-Activated Protein Kinases; D002945:Cisplatin