Establishment of a new human cancer cell line secreting protease nexin-II/amyloid β protein precursor derived from squamous-cell carcinoma of lung

✍ Scribed by Hiroshi Itoh; Hiroaki Kataoka; Hiroyuki Koita; Kazuki Nabeshima; Teruhiko Inoue; Kenji Kangawa; Masashi Koono

• Publisher: John Wiley and Sons
• Year: 1991
• Tongue: French
• Weight: 979 KB
• Volume: 49
• Category: Article
• ISSN: 0020-7136
• DOI: 10.1002/ijc.2910490322

✦ Synopsis

Abstract

A new cell line (LC‐1/sq) of human lung squatnous‐cell carcinoma was established from a surgically resected specimen of primary lung cancer. Upon continuous propagation in serum‐free culture medium, it secreted trypsin inhibitors into the conditioned medium. The major fraction of the trypsin inhibitor (TI‐1) was purified to apparent homogeneity by anion‐exchange and gel‐filtration high‐performance liquid chromatography (HPLC) and sodium dodecyl sulfate polyacrylamide gel electro‐phoresis (SDS‐PAGE) followed by transblotting to Immobilon. TI‐1 effectively inhibited trypsin. Chymotrypsin, plasmin and kallikrein were inhibited to a lesser extent, but urokinase‐type plasminogen activator, elastase, thrombin and papain were not inhibited. The activity of TI‐1 was acid‐stable and heat‐resistant, and its molecular weight was 115 kDa by SDS‐PAGE. It exhibited single NH~2~‐terminal sequence, and its first 20 NH~2~‐terminal amino‐acid residues were identical with those of protease nexin‐II (PN‐II)/amyloid β‐protein precursor (APP). These characteristics of TI‐1 suggest that the major trypsin inhibitor secreted by LC‐1/sq is indistinguishable from PN‐II/APP. LC‐1/sq is the first lung squamous carcinoma cell line that secretes functionally active trypsin inhibitor, PN‐II/APP, in vitro and is useful for studying its biological significance in malignant tumor.