Recombinant Lamprey LIP Affected Human Breast Cancer Cells In Vivo And In Vitro

Lamprey,one of two oldest existing jawless vertebrates.It could competent resist cancer by its ancient and simple structure.Although a new immune system,which is quite different from Ig G system,has been found in lamprey,it is still unclear how the immunologic mechanism works on casual visitor,for example cancer cells.A kind of a secreted protein,isolated and purified from lamprey Supraneural Body cells,performs high cytotoxicity only towards to cancer cells,thus we named it Lamprey Immune Protein(LIP).In consideration of the economical and humanistic reason,we establish prokaryotic expression LIP system using Escherichia coli.At this paper,we check recombination LIP(rLIP)on MCF-7 cells,Hep G2 cells,K562 cells and Jurkat cells,finally these cells are all dyed in a few minutes,but nothing happens to normal kidney cell 293 T,so we think the rLIP performs high selective cytocidal activity.According to the results of transmission electron microscope,scanning electron microscope,ultra high resolution microscopy,we find that rLIP induced MCF-7 cell loss the integrity of plasma membrane,cytoskeleton and organelles.In this process,MCF-7 cell DNA is degraded randomly,and mitochondrial transmembrane potential decreased due to the broken of mitochondrial membrane.At the same time,rLIP increases the level of Reactive Oxygen Species(ROS),which may in turn deteriorate cell death.All of these results indicate that rLIP induces cell death in a necrocytosis-like way.In this paper,we also inject MCF-7 cells on the back of nude mice to ensure generate xenografts.Then the tumors are injected rLIP in vivo or immersed in rLIP ex vitro.Also,we immersed human breast tumor in rLIP ex vitro.After transmission electron microscope observation,HE staining,immunohistochemical coloration,TUNEL assay,we draw a conclusion that rLIP forced numbers of tumor cells died in a type of necrosis.It has been reported VLR immune system in lamprey which had appeared 4 billion years ago.But before us,nobody ever found cytotoxic immune protein in lamprey.Thanks to rLIP,we are closer to work out the origin and evolution of adaptive immune system.