Anti-angiogenesis effect of 3'-sulfoquinovosyl-1'-monoacylglycerol via upregulation of thrombospondin 1.

We previously reported that 3'-sulfoquinovosyl-1'-monoacylglycerol (SQMG) effectively suppresses the growth of solid tumors, likely via its anti-angiogenic activity. To investigate how SQMG affects angiogenesis, we performed DNA microarray analysis and quantitative real-time polymerase chain reaction. Consequently, upregulation of thrombospondin 1 (TSP-1) in SQMG-treated tumors in vitro and in vivo was confirmed. To address the mechanisms of TSP-1 upregulation by SQMG, we established stable TSP-1-knockdown transformants (TSP1-KT) by short hairpin RNA induction and performed reporter assay and in vivo assessment of anti-tumor assay. On the reporter assay, transcriptional upregulation of TSP-1 in TSP1-KT could not be induced by SQMG, thus suggesting that TSP-1 upregulation by SQMG occurred via TSP-1 molecule. In addition, growth of TSP1-KT xenografted tumors in vivo was not inhibited by SQMG, thus suggesting that anti-angiogenesis via TSP-1 upregulation induced by SQMG did not occur, as the SQMG target molecule TSP-1 was knocked down in TSP1-KT transformants. These data provide that SQMG is a promising candidate for the treatment of tumor-induced angiogenesis via TSP-1 upregulation.