THE 5'-FLANKING REGION OF HUMAN CD24 GENE HAS CELL-TYPE-SPECIFIC PROMOTER ACTIVITY IN SMALL-CELL LUNG-CANCER

The human surface antigen CD24 is over-expressed in small-cell lung ca ncer, Here we describe the isolation, sequencing and functional charac terization of the 5'-flanking region of the human CD24 gene. A sequenc e (accession number: YI4692) of 3.4 kb regulates the activity of a luc iferase reporter gene in CD24-expressing small-cell-lung-cancer cell l ines up to 1.6-fold more than the control SV40 promoter and enhancer. In contrast, little or no luciferase activity was detected in 4 non-sm all-cell-lung-cancer cell lines. A deletion fragment of 269 bp had max imal activity in small-cell-lung-cancer cell lines (15- to 20-fold hig her than control), while activity remained 2- to 10-fold below control in non-small-cell-lung-cancer cell lines. We conclude that the CD24 p romoter has a strong and cell-type-specific activity, and propose its exploitation to drive the expression of therapeutic genes in small-cel l lung cancer. (C) 1998 Wiley-Liss, Inc.