Additive cytotoxic effects of radiation and mTOR inhibitors in a cervical cancer cell line

This study investigated the biological effects of mTOR inhibitors associated with radiotherapy in a CC cell line (HeLa). A human keratinocyte cell line (HaCaT) was used as control. Temsirolimus, everolimus, resveratrol, curcumin and epigallocatechin gallate (EGCG) were the mTOR inhibitors assessed. The 50% cell cytotoxicity rate (CC50) for each treatment was determined by MTT cell viability assay. Cells were pre-treated with mTOR inhibitors at CC50 followed by radiotherapy (RT) at 2Gy. Cell death profile after treatment with temsirolimus, resveratrol and curcumin was assessed with flow cytometry. Everolimus, temsirolimus, EGCG, resveratrol and curcumin were cytotoxic to HeLa. Radiation induced a statistically significant (p<0.01) supra-additive cytotoxic effect in the cervical cancer cell line when combined with mTOR inhibitors. After a 24-h treatment, EGCG and resveratrol were more cytotoxic to HeLa cells than to HaCaT cells. After 48h of treatment, resveratrol, curcumin and everolimus were more cytotoxic to HeLa cells when compared to HaCaT cells. After 24h, temsirolimus induced late apoptosis or necrosis in HeLa cells. Based on these data, new studies with mTOR inhibitors as treatment options for cervical cancer are recommended, mainly combined to radiotherapy.
Source: Pathology Research and Practice - Category: Pathology Source Type: research