Detection of loss of heterozygosity in GBM revealed the role of a tumor suppressive gene in regulating glioma progression and tumor recurrence

Abstract

Adducin 3 (ADD3) is a major cytoskeleton protein in glioma cells. Our previous studies demonstrated a significant downregulation of ADD3 in GBM when compared with lower-grade gliomas, and that ADD3 knockdown promoted malignant phenotypes. GBMs are usually characterized by high levels of genomic instability, including frequent loss of heterozygosity (LOH) of chromosome 10q, whilst ADD3 is also located in chromosome 10q25.1-25.2 where it is known to be a tumor-suppressor region. However, it is not known whether ADD3 downregulation in malignant gliomas is associated with allelic loss in 10q. To determine 10q LOH on different polymorphic DNA loci (covering ADD3 locus) on glioma tissues, specimens of Normal, Grade II, Grade III, Grade IV GBM and recurrent GBM tissue were included. DNA fragments were evaluated by using a PCR-based microsatellite capillary electrophoresis and analyzed by a fragment analyzer. LOH status were correlated with patient survival for potential prognostic and diagnostic implications. LOH on ADD3 locus was detected in high grade and recurrent GBMs. It is revealed that downregulation of ADD3 level in GBM is associated with genetic instability of LOH in 10q and associated with recurrence disease. This study would provide significant implications, particularly for understanding pathogenesis of GBM and add valuable credits on the diagnostic as well as prognostic implications.