Detecting Of LHRHR Expressed On Tumor Cell Surface And Targeting Directed By LHRHR

Cancer caused by disorders of the growth and proliferation mechanisms in cells,mainly as the unlimited proliferation and evades immune surveillance, injury the hostorganism, causing the death of the host. At present, radiotherapy, chemotherapy andsurgery is still used as the main methods of treatment on cancer. Commonchemotherapy drugs have very low or do not have specific on tumor cells, causingserious adverse drug reactions on patients. Researchers found that tumor cells areusually specific express a multiple of receptors or biomarkers, use those receptors andbiomarkers to develop the tumor specific targeting agents can reduce the toxic sideeffects of chemotherapy drugs to patients. Tumor receptors play an important role inthe process of carcinogenesis and tumor growth, and is the first targeted as a target oftumor specific treatment. Study on the expression of tumor surface receptors is thekey point of tumor targeting therapy.LHRH receptor is G protein-coupled receptors which associate with sexualmaturation and reproductive, play an important role in regulation of reproductivehormone cascade reaction, participate in multiple of signaling pathways. Human canexpress two types of LHRH receptors: LHRH I receptor and LHRH II receptor, butonly LHRH I receptor is functional full-length LHRH receptor in human body. Theexpression of LHRH receptor has related with cancers, the expression of LHRHreceptor in ovarian cancer, endometrial cancer and prostate cancer has been detected.In this study we detected LHRH receptor expression in a variety of human tumors andnormal tissues to confirm that the LHRH receptor has high expression in a variety oftumor tissues. And cytology experiments to confirm that the cytotoxicity effect oftumor targeting drug LHRH-PE40is accomplished by the mediate of LHRH receptor.RT-PCR results showed that the LHRH receptor gene (319bp) has expressed inboth tumor tissues and rat pituitary, and has no expression in rat normal tissues. TheWestern Blot has showed that the protein samples of tumor tissues, tumor cell lines and rat testis have specific reaction at approximately48KDa, and with no specificreaction bands in rat heart, liver and Lo2, and in different tumor tissues the LHRHreceptor also has different expression level. Immunohistochemical result showed thatnormal breast tissue has no specific staining, and cancer tissues have showed deeplydark brown stain.The cytotoxicity assay results showed that at low concentrations the LHRH-PE40can inhibit the growth of Hep-2and A549cells, and at high concentrations there is asignificant cytotoxicity effect on Hep-2and A549, and this effect is increasing by theincreased of drug concentration. The inhibition of Lo2is not obvious and has nosignificant cytotoxicity effect at high concentrations levels. Binding assay confirmedthat the combination of LHRH-PE40by Hep-2and A459were inseparable, thecombination increased by the time increasing. The LHRH-PE40binging with Lo2wasvery low and was just physical combination. Competitive inhibition test confirmedthat the binding capacity of LHRH-PE40on Hep-2and A549were decreasing byLHRH concentration increased, but has no significant effect on Lo2; the A490valuehas still been at a low level.In summary, most of tumor tissues and cells have expression of LHRH receptors,but there have no expression on normal tissues except the tissues related withreproductive. LHRH-PE40can target binging and have cytotoxicity effect with tumorcells which express the LHRH receptor, and has high affinity with LHRH receptors;but can not binding with normal cells and has no cytotoxicity with it. Different tumorcell lines have different binding capacity with LHRH-PE40, and the conbination canbe competitive inhibited by LHRH.