| ina is the area with high incidence of liver cancer. Due to its high malignancy, hepatocarcinoma is still one of the major diseases threatening people's life. Hepatocellular carcinoma (HCC) is one of the most common malignant tumors with high malignancy and fast deterioration in China. Because most patients were advanced liver cancer when they were admitted to hospital for diagnosis, they lost the chances for operation. And chemotherapy and radiotherapy have limited efficacy for inoperable HCC. So it is urgent to find a safer and more effective way to cure hepatocarcinoma. In recent years, endocrine therapy, as an effective and low toxicity way to cure tumors, has drawn much attention of many pathologists and many clinicians.Gonadotropin-releasing hormone (GnRH) is a decapeptide hormone synthesized and secreted by the hypothalamic neurons. It gets into the lobus anterior of hypophysis by the hypothalamus hypophyseoportal system, acts on the gonadotropic hormone secretingcells in the lobus anterior hypophysis to secrete follicle stimulating hormone (FSH) and luteinizing hormone (LH), and therefore regulates the gonadogenesis and gametogenesis. Much evidence has shown that there exist GnRH-binding sites on tumor cells originating from mammary gland, prostate gland, ovarium, hypophysis and pancreas. GnRH analogs can inhibit the growth of these tumor cells. Experimental studies have also found that the tumor inhibitory effect of GnRH is through a mechanism independent of pituitary gonadotropin releasing activity. Studies also indicate that there exist GnRH-binding sites on hepatocarcinoma cells and GnRH analogs can inhibit the growth of these cells in vitro. But its detailed functional mechanism is still unknown. Some people assume that the inhibitory effect of GnRH analogs on heaptocarcinoma cell growth is through the mechanism of apoptosis. Both experimental studies and clinical observation have indicated that liver cancer might be a hormone-dependent tumor. Recently reports have shown that there are GnRH receptors on cultured human hepatocarcinoma cells and natural GnRH can inhibit the growth of this cell line.Fas, also called APO-1, is now named CD95. It was found by two research groups in their own laboratories in the same year, 1989. FAS belongs to TNF receptor family and NGF receptor family. FasL, which is the natural ligand of Fas in human body, was found in 1994 by Suda et.al, who purified the cytotoxic T lymphocytes in rats by affinity chromatography. Fas is the signal molecule of cell death. When cells expressing Fas are combined with Fas antibody or naturalFasL in the form of trimer, they can activate and transduce the death signal, thus make the target cells with Fas die within several hours. Present studies show that Fas and FasL play an important role in the onset, growth and transfer of tumor.In order to further study the relationship between GnRH and its receptors and the biological characteristic of hepatocarcinoma, we conducted the following experiments:(1) By using immunohistochemical method, the localization of GnRH and its receptors were detected in hepatocarcinoma SMMC7721 cell line, so as to confirm the GnRH receptor protein expression on hepatocarcinoma SMMC7721 cell line.(2) With immunocytochemistry, we observed the expression of Fas/FasL in hepatocarcinoma SMMC7721 cells to provide the morphological evidence for further study of the regulatory effect of Fas/FasL system on the growth of hepatocarcinoma cells.(3) With semi-quantitative RT-PCR method (QRT-PCR), we detected the changes of expression of Fas/FasL- mRNA in hepatocarcinoma SMMC7721 cells stimulated by various concentration GnRH analogs. The purpose of this study was to illustrate the partial mechanism of growth inhibition of hepatocarcinoma cells by GnRH and some passages of signal transduction mediated by GnRH receptor in hepatocarcinoma cells, which might provide the theoretical basis for further study of the GnRH analogs in the treatment of HCC.The main result...
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