Expression Of Circadian Clock Protein Rorb In Human Gastric Cancer

BackgroundGastric cancer is one of the common malignant tumors in the world which showed a rising incidence of death. So far the mechanisms of occurrence of gastric cancer need to be further studied. The prognosis of advanced gastric cancer is very poor, so it’s necessary to search new molecular markers to improve the survival of gastric cancer patients.Our group used to test the expression of RORb mRNA level of several gastric cancer tissues, we found it’s obviously suppressed in gastric cancer tissues. However, the amount of tissue is limited, and the mechanisms still remains unknown.ObjectiveOn the basis of previous studies, we increase the amount of tissues to detect the RORb mRNA level to analysis the expression of RORb in gastric cancer. Explore the mechanisms of RORb in gastric cancer.Methods1. Detection of RORb mRNA level through real-time PCR in 34 gastric cancer tissues;2. Transfection of RORb plasmid to SGC cell line to build cell line which express RORb steadily. Injection of cell above into nude mice to research whether RORb can suppress the growth of gastric cancer cell.3. Analysis of expression pattern of SGC cell which overexpress RORb through gene chip.4. The result of gene chip is analysed through GO in software DAVID.Results1. The expression level of RORb mRNA is suppressed in gastric cancer tissues compared to normal gastric tissues and adjacent cancer tissues.2. The mean volumn of tumor in RORb overexpression group is lower than control group.3. Through Human Genome U133 Plus 2.0 Array analysis, we fount ascend expression of 177 genes and descend expression of 283 genes. And the expression of BCL2L11 increased 5.08 times, the expression of C5orf36 decreased 4.23 times.4. GO analysis shows that genes which show different expression main act on binding、 transferase activity、enzyme regulator activity.ConclusionThe expression level of RORb mRNA is suppressed in gastric cancer tissues; RORb show inhibiting effect in gastric cancer cells; different expression genes involve in nucleic acid, nucleotide metabolism, mRNA transcription, cell cycle, cell proliferation and differentiation, oncogenesis; So it is possible that RORb affect gastric oncogenesis through regulating cell cycle、cell proliferation and differentiation and DNA metabolism.