Combinatorial Antitumor Effect of Rapamycin and β-Elemene in Follicular Thyroid Cancer Cells

Background.mTOR signaling would be a promising target for thyroid cancer therapy. However, in clinical trials, objective response rate with mTOR inhibitor monotherapy in most cancer types was modest. A new focus on development of combinatorial strategies with rapalogs is increasing.Objective.Investigating the combinatorial antitumor effect of rapamycin andβ-elemene in follicular thyroid cancer cells.Methods.MTT assay was used to determine the FTC-133 cell proliferation after culturing with rapamycin and/orβ-elemene. To analyze their combinatorial effect, immunoblotting was performed to analyze the activation status of AKT. Moreover,β-elemene attenuated rapamycin-induced immunosuppression was tested in mice.Results.Combination of rapamycin andβ-elemene exerted significant synergistic antiproliferative effects in FTC-133 cell linesin vitro, based on inhibiting the AKT feedback activation induced by rapamycin.In vivo, theβ-elemene could attenuate rapamycin-induced immunosuppression via reversing imbalance of Treg/Th17, with the underlying mechanism needed to be declared.Conclusions. We demonstrate that the novel combination of mTOR inhibitor withβ-elemene synergistically attenuates tumor cell growth in follicular thyroid cancer, which requires additional preclinical validation.