Expression of neurophysin-related precursor in cell membranes of a small-cell lung carcinoma

L. C. Rosenbaum, E. A. Neuwelt, H. H.M. Van Tol, Y. P. Loh, J. G. Verbalis, I. Hellstrom, K. E. Hellstrom, G. Nilaver

Research output: Contribution to journalArticlepeer-review

28 Scopus citations


A monoclonal antibody (mAb L6) to a small-cell lung carcinoma surface antigen recognizes a common epitope of vasopressin-neurophysin and oxytocin-neurophysin in hypothalamic nuclei. We now report on the identification of a neurophysin-like precursor in human lung carcinoma (LX-1) cell membrane. mAb L6 immunoaffinity chromatography of solubilized membranes resulted in a single band of ≃45 kDa. Western blot analysis demonstrated immunoreactivity of this band with mAb L6, anti-vasopressin, and an antibody to the vasopressin precursor, pro-pressophysin. N-terminal sequencing of this band demonstrated a 21-amino acid homology with the N terminus of human pro-pressophysin, and substitution of a Cys33 residue in the tumor antigen with Arg33. Absence of immunoreactivity with the antibodies described above in cytosolic extracts and culture medium suggests nonsecretion of processed or intact pro-pressophysin-like peptide. Northern analysis of LX-1 mRNA with a 30-mer to the C terminus of rat pro-pressophysin resulted in a band of ≃1000 base pairs, 250 base pairs larger than hypothalamic message. In situ hybridization of LX-1 tumor-bearing nude rat brain with the same probe demonstrated specific hybridization in rat hypothalamus and xenografted tumor. These findings suggest expression of a pro-pressophysin-like protein in this tumor cell line that is preferentially targeted to the cell membrane.

Original languageEnglish (US)
Pages (from-to)9928-9932
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number24
StatePublished - 1990


  • Northern blots
  • Western blots
  • in situ hybridization
  • lung neoplasms
  • tumor antigen

ASJC Scopus subject areas

  • General


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