ATF4 and neoplasm: In addition, as shown in Figure 6E, celastrol triggered extrinsic and intrinsic apoptosis in vivo, as evidenced by the accumulation of apoptosis-related proteins in celastrol-treated tumor tissue, including ATF4, DR5, c-caspase 8, Noxa, FoxO3a, Bim, c-caspase 9, as well as c-caspase 3 and c-PARP.