C-terminal peptides of interleukin-6 modulate the expression of junB protooncogene and the production of fibrinogen by HepG2 cells.
Interleukin-6 (IL-6) is a 185 amino acid residue helical cytokine with various biological activities (e. g. B cell development, acute phase reaction). We have investigated the role of the 168-185 C-terminal region of IL-6 in the induction of fibrinogen synthesis and expression of junB mRNA using synthetic peptides corresponding to this region. Circular dichroism spectroscopy data suggest that even truncated peptides have a strong tendency to adopt an ordered conformation. Peptides were tested alone or in combination with recombinant hIL-6 on an IL-6 responsive human hepatoma HepG2 cell line. The expression of the protooncogene junB monitored by competitive RT-PCR represents an early, while the fibrinogen production detected by sandwich ELISA a late, marker of IL-6 initiated events. We found that peptides--depending on their structure--modulate spontaneous as well as IL-6 induced fibrinogen production and/or mRNA expression of junB by exhibiting inhibition (in the presence of IL-6) or stimulation (in the absence of IL-6).
Igaz
P
P
Department of Genetics, Cell- and Immunobiology, Semmelweis University Medical School, Budapest, Hungary.
Bösze
S
S
Tóth
S
S
Falus
A
A
Hudecz
F
F
D006528:Carcinoma, Hepatocellular / Q000378:metabolism; D002942:Circular Dichroism; D005340:Fibrinogen / Q000096:biosynthesis* / Q000187:drug effects; D006801:Humans; D015850:Interleukin-6 / Q000737:chemistry* / Q000378:metabolism; D008113:Liver Neoplasms / Q000378:metabolism; D008961:Models, Structural; D009842:Oligopeptides / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D017434:Protein Structure, Tertiary; D016755:Proto-Oncogene Proteins c-jun / Q000187:drug effects / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis* / Q000187:drug effects; D014407:Tumor Cells, Cultured / Q000378:metabolism
D015850:Interleukin-6; D009842:Oligopeptides; D016755:Proto-Oncogene Proteins c-jun; D012333:RNA, Messenger; D005340:Fibrinogen