Establishment of a new human cancer cell line secreting protease nexin-II/amyloid beta protein precursor derived from squamous-cell carcinoma of lung.
A new cell line (LC-1/sq) of human lung squamous-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 (T1-1) was purified to apparent homogeneity by anion-exchange and gel-filtration high-performance liquid chromatography (HPLC) and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) followed by transblotting to Immobilon. T1-1 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 T1-1 was acid-stable and heat-resistant, and its molecular weight was 115 kDa by SDS-PAGE. It exhibited single NH2-terminal sequence, and its first 20 NH2-terminal amino-acid residues were identical with those of protease nexin-II (PN-II)/amyloid beta-protein precursor (APP). These characteristics of T1-1 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.
Itoh
H
H
Department of Pathology, Miyazaki Medical College, Japan.
Kataoka
H
H
Koita
H
H
Nabeshima
K
K
Inoue
T
T
Kangawa
K
K
Koono
M
M
D000368:Aged; D016564:Amyloid beta-Protein Precursor / Q000378:metabolism*; D002294:Carcinoma, Squamous Cell / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism* / Q000473:pathology; D008297:Male; D015849:Plasminogen Inactivators / Q000378:metabolism*; D014407:Tumor Cells, Cultured / Q000378:metabolism / Q000473:pathology
D016564:Amyloid beta-Protein Precursor; D015849:Plasminogen Inactivators