Transcription factor EB (TFEB) is a master regulator of autophagy activity and lysosomal biogenesis,but its role in autophagy-mediated cell survival and chemotherapy resistance is not completely understood.In this study,we explored whether TFEB played an important role in autophagy-mediated chemotherapy resistance in human cancer LoVo and HeLa cells in vitro.Treatment of human colon cancer LoVo cells with doxorubicin (0.5 μmol/L) induced autophagy activation and nuclear translocation of TFEB,which resulted from inactivation of the mTOR pathway.In both LoVo and HeLa cells,overexpression of TFEB enhanced doxorubicin-induced autophagy activation and significantly decreased doxorubicin-induced cell death,whereas knockdown of TFEB with small interfering RNA blocked doxorubicin-induced autophagy and significantly enhanced the cytotoxicity of doxorubicin.In LoVo cells,autophagy inhibition by 3-methyladenine (3-MA) or knockdown of autophagy-related gene Atg5 increased cell death in response to doxorubicin,and abolished TFEB overexpression-induced chemotherapy resistance,suggesting that the inhibition of autophagy made cancer cells more sensitive to doxorubicin.The results demonstrate that TFEB-mediated autophagy activation decreases the sensitivity of cancer cells to doxorubicin.