Discovery and development of new antitumor agents from abundant marine fish are attracting an increasing interest. In the present study, we extracted and purified a novel antitumor protein Syngnathusin from the whole body of Syngnathus acus L., a precious marine fish traditionally used for tumors. Syngnathusin was comprised of 16 kinds of amino acids, mainly acidic amino acids. Its molecular weight was 67.3 kDa and its isoelectric point was 4.57. The N-terminal amino acid sequence of Syngnathusin was determined to be Lys-Arg-Asp-Leu-Gly-Phe-Val-Asp-Glu-Ile-Ser-Ala-His-Tyr and showed no significant homology with the known proteins. Syngnathusin could significantly inhibit the growth of A549 and CCRF-CEM cells. However, the obvious proliferation inhibition against human non-tumor cell lines was not observed. Flow cytometry, morphologic assessment and comet assay revealed that Syngnathusin could induce apoptosis in A549 and CCRF-CEM cells and strongly cooperated with MTX. Syngnathusin could inhibit the growth of S180 tumor transplanted in mice. Syngnathusin may be developed as a novel, selective and effective antineoplastic agent.
Keywords: Syngnathus acus; purification; characterization; antitumor; proteinAbbreviations: CTX, cytoxan; 5-Fu, 5-fluorouracil; HCF, human uterine cervical canal fibroblast; HE-21, human embryonic fibroblast; HFL-1, human embryonic lung fibroblast;
OPEN ACCESSMar. Drugs 2012, 10 36 HL-7702, human normal liver cells; IEF-PAGE, isoelectric focusing-polyacrylamide gel electrophoresis; MALDI-TOF-MS, matrix-assisted laser desorption/ ionization time of flight mass spectrometry; MTT, methyl thiazolyl tetrozolium; MTX, methotrexate; PBMC, human normal peripheral blood mononuclear cells; PI, propidium iodide; PVDF, polyvinylidene difluoride; Rp-HPLC, reversed-phase high performance liquid chromatography; RPTEC, human normal renal proximal tubule epithelial cells; SDS-PAGE, sodium dodecylsulphate-polyacrylamide gel electrophoresis; SI, Synergism index; Tris, trisamine.