Secretion of antileucoprotease from a human lung tumor cell line

Abstract

Two human tumor cell lines were analyzed for the production of human antileucoprotease (ALP). One of them, a human squamous lung carcinoma cell line (HS‐24) synthesized, as confirmed by Western blot analysis, high amounts of ALP in serum‐free medium. The supernatant inhibited elastase, chymotrypsin and trypsin. Northern blot analysis with an 18‐mer radiolabelled oligonucleotide, derived from an ALP specific cDNA clone, revealed a specific mRNA of about 700–800 nucleotides in HS‐24 tumor cells. In contrast, a secondary human lung tumor cell line (SB‐3), derived from the adrenal cortex, did not synthesize ALP when assayed under identical conditions. The supernatant inhibited only trypsin and chymotrypsin.