δ-Tocotrienol potentiates the inhibitory effects of interferon alfa 2-B (IFN α) on proliferation, migration, invasion and increases apoptosis in human huh7 hepatocarcinoma cells

Abstract

Our group has previously postulated that δ-tocotrienol supplementationto interferon alfa (IFN α) therapy can be used as a strategyagainst liver cancer cells because combined treatment producedgrowth inhibition and induced apoptosis in SK Hep-1 tumor cells.According to our preliminary results in SK-Hep1 cells, we decided tocheck if they were repeated in another liver tumor cell line (HuH7),doing additional migration and invasiveness studies.Cells were treated with 20000 IU/L IFN α and 25 uM δ-tocotrienol,an isomer of vitamin E (combined IFN-E-group). Also, treatmentswith each single compound were made (IFN-group and E-group).MTT assay was performed to determine cell viability at 72 h of treatment;wound healing assay was done at 24 h to determine cell migration.Invasion studies at 24 h were made in transwell chambers,and annexin v/propidium iodide assay was performed to determineapoptosis at 72 h. As expected, IFN-E-group showed a higher decreasein cell viability (-70%*#) compared with monodrug therapy:IFN-group (-10%*), E-group (-15%*). IFN-E-group displayed a significantdecrease (-44%*#) in migratory activity compared with eachindividual treatment: IFN-group (-21%*) and E-group (-22%*). Also,IFN-E-group showed a significant diminution (-75%*#) in cell invasivenesscompared with monodrug therapy: IFN-group (-25%*) andE-group (-55%*). Finally, IFN-E-group showed a higher increase intotal apoptosis (+160%*#) compared with individual therapy: IFNgroup(-40%*) and E-group (-43%*),(*p≤0.05 vs. control untreatedcells; #p≤0.05 vs IFN-group and E-group). In summary, we demonstratethat the addition of δ-tocotrienol to IFN α therapy enhancesthe reduction of cell proliferation and migration/invasiveness capacitiesof Huh7 cells, as well as potentiates the increase in apoptoticcell death. In this regard, combined treatment of immunochemicalstogether with natural products, might open a potential clinicalaproach for HCC treatment in the future.