Studies And Applications Of Peptide From Meretrix Meretrix Linnaeus

Nowadays,cancer has the highest mortality,is worthy of the name of"the first killer". Many researches reported that the anticancer components extracted from natural organism could combine with special regulation target during the course of growth, develop and malignance of cancer.Screening out those active substances has been the hotspot in the work of finding new effective anticancer medicaments.Since several years ago,many antineoplastic materials with original structures have been identified from marine organisms.And this presents a marvelous prospect in discovering new drug.Screening and extracting antineoplastic agents with unique chemical constitution from marine lives and their metabolites become more and more important. Meretrix meretrix Linnaeus is a kind of popular ocean mollusks,the value of which is not only in the abundant nutrition,but also in the use as a resourse of medicine.It can eliminate cyst and detoxify the body,which means its inhibitory effect on the proliferation of some cancer cells.It can also decrease the level of blood sugar and blood fat and protect body cells from mutation or decrepitude.The active components along with its physiological function have aroused popular attention.In this study,we obtained four peaks by a series of methods including fragmentation, organic precipitation and Sephadex G-25 column chromatogram.We tested the inhibitory effect of four peaks on cancer cells and found that the substance of peak 2 named Mer2 could inhibit the proliferation of cancer cells.And peak1 named Mer1 could inhibit the activity of Tyrosinase.To investigate the biological effects of Mer2 on cells and functional characteristics, Mer2 was used to treat cell lines including the HePG₂ cells,the human cholangiocarcinoma QBC939 cells,Hela cells and the human lung adenocarcinoma SPC-A-1 LTEP-a-2 cells.The result from MTT showed that Mer2 could inhibit growth of all the cell lines above.And the IC₅₀in 72h to HePG₂ and QBC939 cells were all less than 10μg/mL.We investigated the effects of Mer2 on the shape and cell-cycle of liver cancer HePG₂ cells by microscope.The results showed that shapes of cells treated by Mer2 had been changed distinctly,which showed an obvious apoptotic property.It indicated that the inhibitory effect of Mer2 on cancer cell had a relationship with the cell apoptotsis.Proteomics technology was used to study the molecular mechanism of inhibitory effects of Mer2 on the HePG₂.The differentially expressed proteins were analyzed by two-dimensional gel electrophoresis.And totally 89 differentially expressed proteins, 66 of which were down-regulated and 23 were up-regulated,were found on two patterns.One was the control cells proteins pattern,the other was that of cells treated by Mer 2.9 proteins changed markedly were identified by MALI-TOF.And the result showed that the expression levels of 2 proteins were down-regulated and 7 were up-regulated.These proteins included zinc finger protein,Annexin A2,cyskeletal protein,mitochondrial ribosomal protein L27,transcription regulation factors and so on.And we discussed the fuctions of some of these proteins.By using the method of dynamics,we studied the effect of Mer1 on mushroom Tyrosinase.The peptide showed uncompetitive inhibitory effect on Tyrosinase,the value of IC₅₀was 95μg/mL and an uncompetitive type inhibitory effect on the mushroom Tyrosinase,the value of inhibition constant(K_IS)was 60.98μg/mL.We also studied effect of Mer1 on proliferation of B16.And the result showed that Mer1 did not inhibit growth of B16 cells,but it could inhibit the activities of Tyrosinase and melanin in B16 cells.It was able to clear free radicals without any undesirable damages,which displayed that it had certain activity of anti-oxidant;therefore it's a safe additive with potential function of whitening skin.