HBP1, a novel protein from lamprey can repress proliferation of cancer cells (TUM7P.926)

Abstract

Abstract HBP1 ( HMG-box containing protein 1) is homologous to the sequence- specific high mobility group ( HMG) family of transcriptional factor. Previous work had shown that HBP1 inhibits G1 progression in cells. In this paper, we identified a homolog of HBP1 in the Japanese lamprey (Lampetra japonica). The bioinformatics analyses showed that the Lj-hbp1 gene has over 60% sequence identity with its homologs in jawed vertebrates. The open reading frame (ORF) of Lj-HBP1 is 1584 bp long and encoded 527 amino acids. The calculated molecular masses of Lj-HBP1 was 58 kD. Real-time quantitative PCR indicates that the HBP1 appears universally in the lampreys tissues. An Adeno-X-LjHBP1 vector were constructed, HBP1 transcription factor were expressed, and its infection efficiency of the packaged lentivirus were evaluated by PCR method. We found that both human tumor cells and normal cells were infected efficiently as determined by the expression of HBP1. In addition, the proliferation rate and ability of growth in soft agar of the HBP1-transfected Raji cells were suppressed through growth curve test ( population doubling as index) and soft agar assay. The results indicated that modest overexpression of HBP1 inhibited the growth of tumor cells.