A Theoretical Model for the Hormetic Dose-response Curve for Anticancer Agents

In the present article, we quantitatively evaluated the dose-response relationship of hormetic reactions of anticancer agents in vitro. Serial dilutions of gemcitabine, cisplatin, 5-fluorouracil, vinorelbine, and paclitaxel were administered to the A549 non-small-cell lung cancer cell line. The bi-phasic sigmoidal curve with hormetic and cytotoxic effects is given by the formula y=(a-b/(1+exp(c(*)log(x)-d)))/(1+exp(e(*)log(x)-f)), that was used to perform a non-linear least square regression. The dose-responses of the five anticancer agents were fitted to this equation. Gemcitabine and 5-fluorouracil, which had the lowest ED50 for their hormetic reaction, had the most pronounced promotive effects out of the five anticancer agents tested. The hormetic reaction progressed exponentially with culturing time. Our theoretical model will be useful in predicting how hormetic reactions affect patients with malignant tumors.