Purification And Antitumor Activities In MCF-7 Cells Of Lectin From Musca Domestica Larvae

A new lectin was purified from Musca domestica larvae after affinity chromatography and HPLC. Approximately three D-galactose specific lectins were isolated from the crude extract of Musca domestica larvae haemolymph, By HPLC procedure and SDS-PAGE, a new 38 ku Musca domestica larvae lectin (MLL-2) was purified ultimately. Circular dichroism detected the main backbone conformations of MLL-2 areβ-sheet and Random coil. The haemagglutinating activity of the lectin was instability lectin for temperature. Anti-tumor activity of MLL-2 was demonstrated by its inhibition on the proliferation of human breast cancer MCF-7 cells in a time-and dose-dependent manner. The morphology of MCF-7 cells showed changes such as nuclear chromatin condensation and fragmentation. DNA fragment in human breast cancer human breast cancer MCF-7 cells has been detected by TUNEL. Flow cytometric analysis also demonstrated that MLL-2 induced apoptosis of MCF-7 cells through cell arrest at G₂/M phase. Western blotting revealed that MLL-2 induced apoptosis in MCF-7 cells was associated with p53, Bcl-2 and Bad protein. The expression of p53, Bad protein was enhanced. The expression of Bcl-2 protein was decreased; In addition, the caspase-3 relative activity in MCF-7 cells treated with MLL-2 for 48h group was significantly increased compared with control group. MLL-2 induces apoptosis in MCF-7cells and its antitumor activity may be applicable for the treatment of cancers.