Effects Of Salidroside On Mitochondrial Biogenesis And Screening For Anti-cancer Compounds

Mitochondria, as the primary energy-generating system, play an important role in maintaining cellular normal function. Many antioxidant strategies improve mitochondrial biogenesis to reduce the generation of ROS in order to decrease the oxidative stress. Our previous tests conformed that salidroside can reverse intrinsic aging and premature senescence both in vivo and vitro, and this function is related to its anti-oxidant effect. However, it is not clear whether the drug improves mitochondrial biogenesis, which may account for its antioxidative activity. In our study, we intend to employ human liver cells L02and fibroblast cells IMR90to explore the effect of salidroside on mitochondrial biogenesis.At first, we discovered that salidroside can perform anti-oxidation effect in human liver cells L02and fibroblast cells IMR90via decreasing the level of ROS assayed by flow cytometry. Then we used fluorescence microscope and flow cytometry to detect the number of mitochondria in both two cell lines. We found the number of mitochondria increased in both cell lines after treated with salidroside. In the same condition, the activity of Mn-SOD and the mRNA level of Mn-SOD and mitochondrial comlex I were also increased. All of these consequences indicated that salidroside can improve mitochondrial biogenesis in both cell lines. Next, we observed that the expression level of proteins and mRNA of PGC-1α, the main regulatory factor of mitochondrial biogenesis increased in both cell lines treated with salidroside, and AMPK was also activated under this condition.From the first part, we prove that salidroside can improve mitochondrial biogenesis to perform its anti-oxidation function.p53as a main cancer suppressor can effectively inhibit the growth of cancer cells, but this effect can be repressed after it binds to MDM2. Therefore, disrupting the interaction between p53and MDM2becomes one of the main research strategy on anti-cancer drugs. In our study, at first, MTT assay was performed to test the cytotoxicity of compounds in tumor cells which were designed to disrupt the interaction of p53-MDM2.15compounds in60displayed significant growth inhibition in human cancer cells. Then, we found that the levels of p53, MDM2and p21were increased, and PARP cleavage was induced in HCT116cells treated with several compounds among them. The compound numbered as1-4a presented significant dose-dependent. All of these were detected by immunoblotting. Finally, the flow cytometric datum demonstrated that these compounds induced cell cycle arrest in G1phase or G2/M phase and apoptosis in HCT116cells.On part two, our study indicates that part of these compounds can improve the expression and activity of p53to induce cell cycle arrest and apoptosis through disrupting the interaction between p53and MDM2.