Antitumor Activities And Its Mechanism Of Meretrix Meretrix Glycopeptide (MGP₀₅₀₁)

A new glycopeptide(Meretrix meretrix glycopeptide, MGP₀₅₀₁) possessing antitumor activity was isolated from Meretrix meretrix. It's moleculer weight was measured as 15 878Da by SDS-PAGE. MGP₀₅₀₁ consists of 55.18% of saccharide and 44.82% of protein.The antitumor activity of MGP₀₅₀₁ was preliminary assayed in vitro by MTT method. The results revealed that MGP₀₅₀₁ can strongly inhibit the proliferation of human cancer cell strains A549, HO8910, HeLa, KB and SMMC-7721 in a dose-dependent manner, especially to mice cancer cell strain B16. MGP₀₅₀₁ presented good temperature tolerance and the best antitumor activity in neutral solution. It should be noticed that MGP₀₅₀₁ was innoxious to cultured mice spleen lymphocyte. Furthermore, MGP₀₅₀₁ could inhibit adhesion of tumor cells to extracellular martrix, with 50% inhibition rate in 9.5μg/mL. MGP₀₅₀₁ was thus presumed having inhibition to tumor cell migration and transferation.Antitumor effect of MGP₀₅₀₁ to the growth of S₁₈₀, Heps and EAC in tumor-bearing mice were also assayed in this paper. At the dosage of 6mg/kg iv, MGP₀₅₀₁ had a distinct inhibition effect to the growth of S₁₈₀ and Heps, with inhibition rate of 68.5% and 66.43%, respectively. Abnormal karyokinesis of tumor histocyte treated with MGP₀₅₀₁ was observed by microscope, which indicated the probable target of antitumor activity ofMGP₀₅₀₁。Mechanism in antitumor were also discussed in the paper. The damage effect of MGP₀₅₀₁ to tumor cell were observed in electronic scan microscope. Tumor cell treated with MGP₀₅₀₁ presented typical apoptosis characteristic in morphology including crenate membrane, condensed nuclear and margination of nuclear chromatin by cytoplasmic vacuolation. Nucleic DNA fractionized and profiled as ladders in agarose electrophoresis. Variation in cell cycle of treated tumor were measured by flow cytometer. Most of the...