| Hepatocellular carcinoma (Primary Hepatocellular Carcinoma, PHC) is one of themost common tumors in the world. It is the third leading cause of cancer-related deathworldwide.It has the following characteristics: concealed cancer pathogenesis, rapidprogress, high degree malignancy high mortality rate and high postoperative recurrencerate at initial stage. In China, liver cancer is the second leading cause of cancer death atpresent. Liver cancer prevention and control work has a long way to go. It is effective tostudy on the mechanism of the occurrence and development of hepatocellular carcinomain-depth, liver cancer prevention and treatment could be worked.Notch signaling pathway is a highly conserved signal pathway during evolution. Itexists widely both invertebrates and vertebrates. It is one of the most main signal pathsbetween the cells, which mainly involved in the process of proliferation, apoptosis anddifferentiation of multicellular organism. In some human cancers, Notch receptors andsignaling pathways express aberrant. They were proved as cancer suppressor genes orcancer-promoting genes. This mechanism had been reported in many malignant tumors,such as colon cancer, non-small cell lung cancer, pancreatic cancer, cervical cancer, renalcell carcinoma and lymphatic system tumor. Therefore, the Notch signaling pathway maybe a potential target for cancer therapy.The expression of Hes1(hairy enhancer of split1) gene is regulated by transmembraneprotein Notch, which is called Notch-hes1signal pathway. Studies have shown that, Hes1gene plays an important role in maintaining the undifferentiated state of various precursorcells. It can keep the number of undifferentiated cells, to ensure the right differentiationdirection. At the same time, it has the option to the fate of differentiation. Recent studiesuncovered that Hes1gene can negatively regulate the asymmetric mitosis of stem cell, andmaintain the self-renewal ability. In addition, It was reported that Hes1gene usuallyexpress abnormally，which suggests that in some extent, the expression of Hes1gene mayaffect the growth and differentiation of cancers.Our research here will study of the thefunction of Hes1in the genesis of primary hepatocarcinoma. We detected the expression of Hes1by Realtime-PCR and and Western blot in mousehepatocellular carcinoma cell lines Hep1-6and H22. We found that Hes1gene showedsignificantly higher expression in these two cancer cell lines than that in liver tissue. Inorder to study the function of Hes1gene in liver carcinogenesis, we constructed shRNAlentivirus expressive vectors specific to Hes1gene, and established Hes1-knockdown cellline Hep1-6-sh-Hes1, which was used to test the proliferation, migragation in vitro and theability of tumor-genesis in vivo after the expression of Hes1was reduced..The proliferation of Hes1cell lines Hep1-6from liver cancer were significantlyinhibited after the silence of HES1though measuring cell proliferation curve,colony-forming ability and cell proliferation index measurement. Cell scratch experimentresult showed that the attacking ability of liver cancer cells was reduced after gene silenceof Hes1. By PI staining, we observed apoptosis and cell cycle process of Hep1-6livercancer cell, of which HES1was silenced. The liver cancer cells were blocked in the cellcycle G1phase, and the expression of cell cycle related proteins also got a correspondingchange, such as the expression of CDK2, CDK4and CDK6was reduced,while theexpression of p21and p53was higher than before. In some extent, silencing HES1couldregulate the expression of cell cycle related genes in order to inhibit the growth of livercancer cell. In addition, experiment on NOD/SCID mice with tumor showed thattumorigenicity of Hep1-6cells of Hes1silence in nude mice was significantly reduced.Therefore, Hes1could be one of the necessary factors for tumorigenesis in vivo. All aboveshowed a close relationship between Hes1and hepatocellular carcinoma. In order toconfirm this association,5clinical samples were picked from patients with primarycarcinoma of the liver to check the HES1expression. it was showed that HES1expressedhigher in primary hepatocellular carcinoma, which was the same as it in mice. Theseprovided a basis for the further research on the mechanism of how Hes1played a role inliver cancer, and laid a foundation for establishing new methods of diagnosis and treatmentof primary liver cancer also.This study was the first to show the higher expression of Hes1gene in primaryhepatocellular carcinoma. The constructed shRNA lentivirus expressive vectors specific toHesl gene inhibit the expression of Hesl efficiently in Hep1-6cell line．It was an importanttools to study the functions of Notch-Hes signal pathway and the relationship with PHC．This study preliminary discussed the effection of Hes1gene silencing on hepatomacells. However, the precise mechanism of Hes1gene is not clear yet, and further study isnecessary. It is possible to provide a new method and thought for the treatment anddiagnosis of primary hepatocellular carcinoma. |
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