Calcitonin increases transcription of parathyroid hormone-related protein via cAMP.
Transcriptional regulation of the human parathyroid hormone-related protein (PTHrP) gene by calcitonin was examined in a lung cancer line (BEN cells). Northern analysis demonstrated that calcitonin caused a rapid 4.5-fold elevation in PTHrP mRNA. Transient transfection of a construct containing 1119 base pairs of the human PTHrP gene 5' to the ATG start site of translation, fused to the CAT reporter sequence, was used to demonstrate a five-fold increase in transcription by calcitonin. Similar increases were also observed when transfected cells were exposed to a number of cAMP agonists including forskolin, as well as isobutyl-methylxanthine. A putative cAMP responsive element (5'-TGACTTCA-3') present within exon 4 was placed upstream of the heterologous SV40 promoter. Expression of this construct was elevated 4.5-fold in response to calcitonin and 7-fold in response to forskolin. Similar responses to calcitonin occurred with a smaller construct (pZMR30) containing 530 bp of sequence upstream of the ATG start site. Thus we postulate that calcitonin acts at least partially via cAMP through this element in exon 4 of the human PTHrP gene.
Chilco
P J
PJ
University of Melbourne, Department of Medicine, Royal Melbourne Hospital, Victoria, Australia.
Gerardi
J M
JM
Kaczmarczyk
S J
SJ
Chu
S
S
Leopold
V
V
Zajac
J D
JD
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D001483:Base Sequence; D003994:Bucladesine / Q000494:pharmacology; D002116:Calcitonin / Q000494:pharmacology*; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000502:physiology*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D006801:Humans; D015759:Ionomycin / Q000494:pharmacology; D008175:Lung Neoplasms / Q000473:pathology; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000096:biosynthesis* / Q000235:genetics; D044162:Parathyroid Hormone-Related Protein; D014176:Protein Biosynthesis; D011506:Proteins / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D012334:RNA, Neoplasm / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics; D012045:Regulatory Sequences, Nucleic Acid; D015290:Second Messenger Systems / Q000187:drug effects; D014158:Transcription, Genetic / Q000187:drug effects*; D014407:Tumor Cells, Cultured / Q000187:drug effects
D009363:Neoplasm Proteins; C470121:PTHLH protein, human; D044162:Parathyroid Hormone-Related Protein; D011506:Proteins; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D011993:Recombinant Fusion Proteins; D005576:Colforsin; D015759:Ionomycin; D003994:Bucladesine; C028815:salmon calcitonin; D002116:Calcitonin; D000242:Cyclic AMP; D015056:1-Methyl-3-isobutylxanthine