Study On Apoptosis Mechanism Of Lectin From Musca Bomestica Larva In Human Breast Cancer

In recent years, cancer is increased by every year. The treatment method is interested by the world. The purpose of this study is purified from Musca domestica larvae with anti-tumor activity of the lectin, examine its inhibitory effect on breast cancer cells to study the mechanism of tumor cells. For the development and application of active substances to provide strong scientific evidence, and provide new material for new drug development.Lectins are a class of non-immunogenic glycoprotein, which has ability of agglutinate cells and precipitate polysaccharides. Lectin, generally present in many species and various tissues of higher organisms, some of the lectin also has anti-tumor activity.Methods by using affinity chromatography, A lectin purified from Musca domestica larvae (38kDa) was known to inhibit the growth of MCF-7cells with90μg/mL, but no significant inhibition on normal cells. After AO/EB and Hochest/PI staining, we can see the typical apoptotic morphology that chromatin condensation by laser scanning confocal microscope. These indicate that lectin associates with cell apoptosis. It is found that MCF-7apoptosis is induced by lectin via reactive oxygen species (ROS) accumulation, result mitochondrial permeability transition pore (MPTP) opening, mitochondrial membrane potential (ΔΨm) gradually decreased with time, cytochrome C (cyt c) in mitochondria released into the cytoplasm through the PTP. In addition, Ca2+can control lectin-induced apoptosis in MCF-7cells, and is regulated by ROS accumulation. Western blotting data dispiay, expression of JNK protein increase in MCF-7cells, and JNK is regulated by ROS. Flow cytometry data show, apoptosis rate fall from15.5%to7.58%with JNK inhibitor SP600125. These show that the SP600125can inhibit the proliferation of MCF-7cells. Then JNK participate in the lectin induced apoptosis process. Then lectin induce Bcl-2and Bax expression. the proportion of Bax and Bcl-2protein expression increased, cyt c is released and caspases are activated, cleaved-caspase-9and cleaved-caspase-6expression increased, laminA cleavage.Taken together, these studies consider that lectin induces apoptosis through a ROS-JNK mediated Caspase and ROS-PTP pathway.