PRELIMINARY STUDY ON THE ANTITUMOR ACTIVITIES OF PROTEOGLYCAN FROM RUDITAPES PHILIPPINARUM
ZHANG Li, LIU Wan-Shun, HAN Bao-Qin, LIU Wen, LIU Bing (College of Marine Life Sciences and Technology,Ocean University of China,Qingdao,266003)
Marine animals provide us a wide variety of structurally unique,biologically significant substances for human being's benefits.Sponges,bryozoans,and ascidians are among the most promising groups.The compounds with antimicrobial and antitumor activity have been frequently found in marine mollusks.Ruditapes philippinarum,belonging to Ruditapes,Veneridae,Bivalvia,is frequently taken as tasty seafood and also a traditional medicine in the Far East for its nutrients and bioactivities for treating internal fever,infections and tumescence. So far no report is available on the antitumor effect of proteoglycan extract from R.philippinarum both in vitro and in vivo.In this study,we studied the antitumor activities of purified extract from R.philippinarum flesh using tumor-bearing mice and cell lines. Two proteoglycans(PG1,PG2)were purified from hot water extract of R.philippinarum.PG1 was a single Mw 20000 proteoglycan,containing 70.09% of polysaccharide and 15.4% of protein.PG2 contained 82.53% of polysaccharide and 7.26% of protein.The inhibition ratio for SMMC-7721 cells of PG1 at concentration of 200μg/ml was 73.30%,and increasing concentration did not enhance the inhibitory effect obviously.PG2 inhibited SMMC-7721 cells proliferation in a dose-dependent manner,and it achieved the same inhibitory effect at concentration of over 500μg/ml as PG1 achieved at 200μg/ml.PG1 did not inhibit the growth of human hepatocyte cell HL-7702 when tested in the same concentrations shown to be cytotoxic towards tumor cells.PG1 exhibited antitumor activity against Sarcoma 180 in KM mice at the dosage of 125—500mg/kg with an inhibition ratio of 24.74%—42.27%,and could enhance the immune function of tumor-bearing mice.The authors believed that the antitumor effect of PG1 is probably host-mediated and cytocidal.