Suprabasin as a novel tumor endothelial cell marker.
Bottom Line: SBSN knockdown inhibited the migration and tube formation ability of TEC.We also showed that the AKT pathway was a downstream factor of SBSN.These findings suggest that SBSN is involved in the angiogenic potential of TEC and may be a novel TEC marker.
Affiliation: Vascular Biology, Frontier Research Unit, Institute for Genetic Medicine, Hokkaido University, Sapporo, Japan; Department of Oral Pathology and Biology, Graduate School of Dental Medicine, Hokkaido University, Sapporo, Japan.Show MeSH
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Mentions: To clarify the role of SBSN in TEC, we used mTEC isolated from human tumor xenografts (A375SM and OS-RC-2). mNEC were isolated from mouse dermis as a normal control. We verified that mNEC and mTEC had the characteristics of EC using an RT-PCR assay (Suppl. Fig. S2). The SBSN mRNA expression levels were upregulated in mTEC from melanoma and renal carcinoma compared with mNEC (Fig. 2a) and other mouse normal tissues (Suppl. Fig. S3). To evaluate the SBSN function in TEC, we examined the migration ability and tube formation of mTEC following the SBSN knockdown. The efficacy of RNA interference (RNAi) was confirmed using quantitative real-time PCR, which showed that siSBSN, unlike control siRNA, decreased the SBSN mRNA level in mTEC and mNEC (Fig. 2b). We next demonstrated that the SBSN knockdown significantly suppressed cell migration toward VEGF-A in mTEC but not in mNEC (Fig. 2c). However, siSBSN had no effect on cell proliferation in either mTEC or mNEC (Suppl. Fig. S4). In this study, we used two types of siRNA and obtained similar results. This suggests that the results are not off-target effects of the nucleic acids. In addition, the junction number of endothelial tubes in mTEC was reduced by siSBSN treatment (Fig. 2d). These findings revealed that SBSN contributed to the angiogenic phenotype, such as migration and tube formation in mTEC.
Affiliation: Vascular Biology, Frontier Research Unit, Institute for Genetic Medicine, Hokkaido University, Sapporo, Japan; Department of Oral Pathology and Biology, Graduate School of Dental Medicine, Hokkaido University, Sapporo, Japan.