TP53 and triple-negative breast carcinoma: Knockdown of ClpP attenuates ONC201-induced cell death but not PG3-induced cell death To compare whether siRNA silencing of ClpP will rescues cell death induced by PG3, PG3-Oc or ONC201, ONC201-sensitive HCT116 p53–/– and MDA-MB-468 triple-negative breast cancer cell lines were treated with the three compounds respectively, and then apoptosis marker cleaved-PARP was probed by western blot.