PMID: 15375558Sep 18, 2004Paper

Evidence for transcriptional repression of SPARC-like 1, a gene downregulated in human lung tumors

International Journal of Oncology
Silvia G IslerSusanne Schenk

Abstract

SPARCL1 mRNA was shown to be downregulated in NSCLC as well as in prostate, colon, and bladder carcinomas. Therefore, SPARCL1 was suggested to be a tumor suppressor gene. By microsatellite analysis, real-time quantitative PCR, and sequence analysis of all exons including the intron-exon junctions and a part of the putative promoter region, we could not find any deletion or mutation that might be responsible for the downregulation of SPARCL1 in NSCLC. We conclude that SPARCL1 is therefore not a classical tumor suppressor gene with a deletion or mutation in one allele and another mutation in the second allele. To test whether SPARCL1 could be downregulated by repression of transcription we performed luciferase reporter gene assays with 10 different SPARCL1 promoter constructs. These experiments revealed that the presence of exon 1 is able to cause a reduction in luciferase activity. Furthermore, we show that the inhibitory activity of exon 1 can be transferred to a heterologous promoter. This indicates that SPARCL1 downregulation might be mediated (at least in part) through transacting factors that bind to exon 1.

Related Concepts

Related Feeds

Bladder Carcinoma In Situ

Bladder Carcinoma In Situ is a superficial bladder cancer that occurs on the surface layer of the bladder. Discover the latest research on this precancerous condition in this feed.