Gastric cancer radiotherapy: A comparativestudy between free eugenol and eugenol-loadedmesoporous silica nanoparticles in enhancing the sensitivityof AGS human gastric cancer cell lines to radiation

Introduction: Gastric cancer is one of the most common cancerswith a high mortality rate worldwide. Radiotherapy is aneffective method for cancer treatment; however, it has severalside effects on adjacent normal cells. The synergistic effect betweenradiation and natural compounds leads to the use of lowerradiation doses and fewer side effects. Eugenol is a naturalcompound with antioxidant, anti-inflammatory, and anti-cancerproperties. Mesoporous silica nanoparticles (MSNs) have beenused for advanced drug delivery. The aim of the present studywas to investigate the effect of free eugenol and eugenol-loadedmesoporous silica nanoparticles (eugenol-MSNs) in increasingthe sensitivity of AGS human gastric adenocarcinoma cell linesto radiation.Methods: The MSNs were synthesized and loaded with eugenol.Eugenol-MSNs were characterized by FTIR and SEM.AGS cells were cultured in RPMI۱۶۴۰ complete medium supplementedwith ۱۰% FBS and ۱% streptomycin/penicillin andmaintained at ۳۷ °C in a humidified incubator with ۵% CO۲.The cells were treated with different concentrations of freeeugenol and eugenol-MSNs for ۲۴h and then exposed to Gammaradiation at ۰, ۱, ۳, and ۵ Gy. The MTT assay was performedafter ۴۸h to determine cell viability.Results: The synthetic MSNs were uniform in size and shape,and drug loading was confirmed. Free eugenol significantly increasedthe sensitivity of AGS cells to irradiation at ۳ and ۵ Gy.Eugenol-MSNs failed to significantly increase the sensitivityof AGS cells at ۱, ۳, and ۵ Gy irradiation compared to nonirradiatedcells.Conclusion: The results of our study indicate that the combinationof free eugenol and radiation significantly inhibited theviability of AGS cells compared to radiotherapy alone. Therefore,the combination of free eugenol and radiation potentiallyallows the reduction of radiotherapy doses and their side effectsin gastric cancer treatment.