Anti-GSPT1 monoclonal antibody Made to order

The human eukaryotic release factor 3a (eRF3a), encoded by the G1 to S phase transition I gene (GSPT1; alias eRF3a), is upregulated in various human cancers. GSPT1 contains a GGC(n) polymorphism in exon 1, encoding a polyglycine expansion in the N-terminal of the protein. The longer allele, GGC(12), was previously shown to be associated to cancer. The GGC(12) allele was present in 2.2% of colorectal cancer patients but was absent in Crohn disease patients and in the control group. Real-time quantitative RT-PCR analysis showed that the GGC(12) allele was present at up to 10-fold higher transcription levels than the GGC(10) allele (P < 0.001). No GSPT1 amplifications were detected, and there was no correlation between the length of the alleles and methylation levels of the CpG sites inside the GGC expansion. Using flow cytometry, we compared the levels of apoptosis and proliferation rates between cell lines with different genotypes, but detected no significant differences. Finally, we used a cytokinesis-block micronucleus assay to evaluate the frequency of micronuclei in the same cell lines. Cell lines with the longer alleles had higher frequencies of micronuclei in binucleated cells, which is probably a result of defects in mitotic spindle formation. Altogether, these findings indicate that GSPT1 should be considered a potential protooncogene. (C) 2009 Elsevier Inc. All rights reserved.

Gastric cancer remains a major cause of death in the developed countries, and a large percentage is still genetically unexplained. Because of their major role in cell survival, mutations in translation factors and altered expression of these genes have been associated with cancer development. Apart from its role in translation termination, the eukaryotic translation release factor 3 (eRF3) is involved in several critical cellular processes, such as cell cycle regulation, cytoskeleton organization and apoptosis. The aim of this study was to evaluate eRF3/GSPT1 gene as a potential genetic susceptibility associated locus for gastric cancer, analysing a stable GGC expansion in exon 1 encoding a polyglycine tract in the N-terminal domain of the protein. DNA was obtained from 139 patients with gastric cancer and from 100 individuals of a healthy control population. The GGC expansion was amplified by PCR and the number of repeats determined by genotyping in an automatic sequencer. There are five known alleles encoding from 8 to 12 glycines. The most common allele encodes 10 glycines. The 12-Gly allele was detected exclusively in the cancer patients (allelic frequency = 5%). Regardless of the genotype, patients with the 12-Gly allele had a 20-fold increased risk for gastric cancer. We also detected a single-base alteration in the gene (G274T) although no correlation with cancer development has been found. Thus, our results show that the GGC expansion may have a potential role in regulating eRF3/GSPT1 expression and/or changing the protein function that can lead to gastric cancer development.