Increased stability of P21(WAF1/CIP1) mRNA is required for ROS/ERK-dependent pancreatic adenocarcinoma cell growth inhibition by pyrrolidine dithiocarbamate.
We present evidence that pyrrolidine dithiocarbamate (PDTC) inhibits growth of p53-negative pancreatic adenocarcinoma cell lines via cell cycle arrest in the S-phase, while it has no effect on primary fibroblast proliferation. Growth inhibition of cancer cells is dependent on ROS and ERK1/2 induction as indicated by a significantly reduced PDTC-associated growth inhibition by the free radical scavenger N-acetyl-L-cysteine (NAC) or the MEK/ERK1/2 inhibitor (PD98059). Moreover, ERK1/2 induction is dependent on ROS production as demonstrated by a complete removal of PDTC-mediated ERK1/2 phosphorylation by NAC. p21(WAF1/CIP1) activation has a central role in growth inhibition by PDTC, as revealed by P21(WAF1/CIP1) silencing experiments with antisense oligonucleotide, and occurs via increased mRNA stability largely mediated by ROS/ERK induction. Conversely, PDTC does not affect P21(WAF1/CIP1) gene expression in primary fibroblasts, although it is able to activate p53 and the p53-regulated antioxidant SESN2. These results suggest that the resistance of fibroblasts to the cytotoxic action of PDTC may be related to the up-regulation of p53-dependent antioxidant genes. Finally, in vivo studies on PaCa44 cells subcutaneously xenografted in nude mice show that treatment with 100 or 200 mg/kg PDTC reduces of 30% or 60% the tumour volume, respectively, and does not cause any apparent form of toxicity.
Donadelli
Massimo
M
Department of Morphological and Biomedical Sciences, Section of Biochemistry, University of Verona, Strada Le Grazie, 8, 37134 Verona, Italy.
Dalla Pozza
Elisa
E
Costanzo
Chiara
C
Scupoli
Maria Teresa
MT
Piacentini
Paolo
P
Scarpa
Aldo
A
Palmieri
Marta
M
D000111:Acetylcysteine / Q000494:pharmacology; D000230:Adenocarcinoma / Q000188:drug therapy*; D000818:Animals; D002453:Cell Cycle / Q000187:drug effects*; D045744:Cell Line, Tumor / Q000166:cytology; D049109:Cell Proliferation / Q000187:drug effects*; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics / Q000378:metabolism*; D017931:DNA Primers; D005347:Fibroblasts; D005419:Flavonoids / Q000494:pharmacology; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D020868:Gene Silencing; D006801:Humans; D015151:Immunoblotting; D051379:Mice; D016376:Oligonucleotides, Antisense; D010190:Pancreatic Neoplasms / Q000188:drug therapy*; D011759:Pyrrolidines / Q000494:pharmacology* / Q000627:therapeutic use; D020871:RNA Stability; D017382:Reactive Oxygen Species / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013859:Thiocarbamates / Q000494:pharmacology* / Q000627:therapeutic use
C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D017931:DNA Primers; D005419:Flavonoids; D016376:Oligonucleotides, Antisense; D011759:Pyrrolidines; D017382:Reactive Oxygen Species; D013859:Thiocarbamates; C020972:pyrrolidine dithiocarbamic acid; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; D000111:Acetylcysteine