Studies On The Antitumor Activity Of Lectin From Musca Domestica Larva In Liver Cancer

Lectins, a class of carbohydrate-binding non-immunogen proteins, are known to possess the ability to agglutinate cells or precipitate polysaccharides. Lectins are found in all kinds of species and in a diversous of tissues of higher organisms, some lectins have antitumor activity.A59kDa lectin was purified from Musca domestica larva by affinity chromatography on a Sepharose4B column, which processed ability of agglutinating rabbit cells.Musca domestica larva lectin (MLL) around59kDa inhibited the growth of human liver cancer cells BEL-7402in a time-and concentration-dependent relationship while it showed less inhibition on human normal liver cells L-02. The result of HE standing and Hoechst33258staining indicated that MLL inhibited the proliferation of BEL-7402cells based on the observation of typical apoptotic morphological cancer cells’changes, such as nuclear chromatin condensation and DNA fragmentation. Flow cytometric analysis also demonstrated MLL caused apoptosis of BEL-7402cells through the cell arrest at G1phase. MLL induced mitochondria to generate ROS accumulation which indicated the potential loss of mitochondrial transmembrane. The apoptosis induced by MLL is associated with Bcl-2down-regulation, Bax translocation, mitochondrial cytochrome c release and caspase-3and caspase-9activation, suggesting that apoptosis through the mitochondria dependent pathway.Compared with the control and positive group, MLL could cause H22cell apoptosis. And MLL didn’t decrease the immunization activity of the H22bearing mice. The mRNA expression of INF-γ and IL-2increased in spleen lymphocytes cell induced by MLL. Flow cytometric analysis also demonstrated MLL caused apoptosis of H22cells through the cell arrest at G2/M phase. RT-PCR showed the expression of TNF-α was increased while NF-κB was decreased.