Anti-cancer Effects Of Emodin On HepG2 Cells As Revealed By ~1H-NMR Based Metabolic Profiling

Hepatocellular carcinoma(HCC)is one of the most common cancer leading to death worldwide with the high incidence rates.Surgeries and chemotherapeutic agents are the treatments for the patients while they are expensive and have side effects.Some ingredients as pharmacological components with low toxicity have anti-cancer activity while it is easy to extract from traditional Chinese medicine process.Emodin,a main active component in the roots and rhizomes of Polygonum multiflorum Thunb,exhibited the anti-cancer activity in clinical studies.However,the molecular mechanisms of emodin-mediated growth inhibition and cytotoxicity of HepG2 cells have not been fully elucidated.In this study,HepG2 cells were selected as recipient cells to study the anti-tumor mechanism of emodin.At first,the MTT assay was used to measure cell viability of HeqG2 cells.We found that emodin can inhibit the proliferation of HepG2 cells with time and dose-independent manner.And then,we divided the cells into control group,low,middle and high dose groups according to IC50 values for 24 hours for NMR analysis.Finally,the 1H NMR data of the cell samples were analyzed by orthogonal signal-partial least square method(OSC-PLS-DA),and relatively quantitative analysis of intracellular small molecule metabolites.The results showed that exposure to emodin significantly influenced many endogenous metabolites.The levels of the genes related to glycolysis pathway were measured by qRT-PCR,indicating that emodin downregulated the genes levels of HKII,PKM2 and LDHA.Meanwhile,we detected the intracellular ROS,cell cycle and apoptosis using flow cytometry.We found that emodin can increase intracellular ROS,disrupt cell cycle and induce apoptosis.The multivariate statistical analysis,molecular biological methods and correlation network analysis revealed disturbed metabolites concerning energy metabolism,amino acid metabolism,oxidative stress and apoptosis.