MUC5AC mucin gene regulation in pancreatic cancer cells.
MUC5AC is a secretory mucin normally expressed by the surface mucous cells of the human stomach and in the bronchial tract. It is absent from normal pancreas, but de novo expression of this mucin occurs in early-stage pancreatic intraepithelial neoplasias and in the invasive ductal adenocarcinoma of the pancreas, prompting this study of MUC5AC gene regulation in pancreatic cancer cells. Promoter deletion constructs and EMSA studies revealed that transcription factors Sp1 and AP-1 are both involved in basal transcription of the MUC5AC gene. Phorbol 12-myrisate 13-acetate (PMA) increased MUC5AC mRNA expression and transcriptional activities of MUC5AC promoter-reporter deletion constructs containing AP-1 consensus sites. EMSA studies showed that Fos/Jun binding to putative AP-1 sites is increased by PMA treatment. Western blot analysis showed that ERK, JNK and p38 are all activated by PMA treatment in SW1990 cells. Inhibitors of mitogen-activated protein/extracellular signal regulated kinase (MEK), such as ERK inhibitor PD98059 and JNK inhibitors dicumarol and SP60015, but not p38 inhibitor SB203580, inhibited PMA-induced MUC5AC reporter activity. Our studies indicate that Sp1 is involved in basal MUC5AC promoter activity while AP-1 is involved in basal and PMA-induced MUC5AC promoter activation in pancreatic cancer cells. Furthermore, PMA-induced MUC5AC gene transcription appears to be mediated by activating Sp1, PKC/ERK/AP-1 and PKC/JNK/AP-1 pathways.
Kato
Shingo
S
Gastrointestinal Research Laboratory, 151M2, Veterans Affairs Medical Center, San Francisco, CA 94121, USA.
Hokari
Ryota
R
Crawley
Suzanne
S
Gum
James
J
Ahn
Dae-Ho
DH
Kim
Jong-Woo
JW
Kwon
Sung-Won
SW
Miura
Soichiro
S
Basbaum
Carol B
CB
Kim
Young S
YS
D021441:Carcinoma, Pancreatic Ductal; D045744:Cell Line, Tumor / Q000378:metabolism*; D024202:Electrophoretic Mobility Shift Assay; D015972:Gene Expression Regulation, Neoplastic; D017930:Genes, Reporter; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D008156:Luciferases / Q000235:genetics; D020935:MAP Kinase Signaling System / Q000187:drug effects; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D055271:Mucin 5AC; D009077:Mucins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D010190:Pancreatic Neoplasms; D011401:Promoter Regions, Genetic; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis; D016329:Sp1 Transcription Factor / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014158:Transcription, Genetic; D014162:Transfection
C524678:MUC5AC protein, human; D055271:Mucin 5AC; D009077:Mucins; D047428:Protein Kinase Inhibitors; D012333:RNA, Messenger; D016329:Sp1 Transcription Factor; D018808:Transcription Factor AP-1; D008156:Luciferases; D011493:Protein Kinase C; D048031:JNK Mitogen-Activated Protein Kinases; D020929:Mitogen-Activated Protein Kinase Kinases; D013755:Tetradecanoylphorbol Acetate