Proteomic analysis of anti-tumor effects by tetrandrine treatment in HepG2 cells

Tetrandrine (TET), a bis-benzylisoquinoline alkaloid isolated from the root of Hang-Fang-Chi (Stephenia tetrandra S Moore), exhibits broad pharmacological effects, including anti-tumor activity. Recently, the beneficial effects of TET on cytotoxicity towards tumor cells, radiosensitization, circumventing multidrug resistance, normal tissue radioprotection, and antiangiogenesis have been examined extensively. To explore the potential molecular mechanism of the anti-tumor effect of TET, we applied proteomic tools to profile the proteins in HepG2 cells subjected to TET treatment. The levels of 39 proteins in cells exposed to TET (IC₅₀=5±0.6 μg/ml) for 48 h were observed to undergo significant alterations. Six proteins were identified by matrix assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS) using peptide fingerprinting from 10 protein spots (density difference >1.5-fold between the control and TET-treated group). Among them, 5 proteins were downregulated (proteasome activator complex subunit 3, 40S ribosomal protein S12, phosphoglycerate mutase 1, destrin, transaldolase) and 1 protein was upregulated (guanylate kinase 1) by TET treatment in HepG2 cells as determined by spot volume (P<0.05). Most of the identified proteins were associated with tumor growth, migration, and anti-tumor drug resistance. These data will be helpful in elucidating the molecular mechanism of TET's anti-tumor effect in HepG2 cells.