Talazoparib

Different co-treatments or pre-treatment strategies were followed for each combined therapy. For liposomal doxorubicin and olaparib treatment, the cells were pre-treated for 6 h with 100 nM Dox-NP (Avanti^®, Alabaster, AL, USA), followed by treatment for 60 h with 1 μM olaparib. For temozolomide (TMZ) (Sigma Aldrich, Taufkirchen, Germany) and olaparib co-treatment, the cells were pre-treated for 48 h with 50 μM temozolomide before co-treatment with 1 μM olaparib for 24 h. Single treatments with [¹²⁵I]-PARPi-01 (~1 MBq/10⁶ cells), olaparib (1 μM), dinaciclib (5 μM; Sigma), and talazoparib (10 nM; Axon Medchem, Groningen, Netherlands.) were done for 72 h, dinaciclib (5 μM), and 1 μM olaparib co-treatment was done for 72 h. For Dox-NP and [¹²⁵I]-PARPi-01 combination, the cells were pre-treated with 100 nM Dox-NP 6 h prior to incubation with [¹²⁵I]-PARPi-01 (~1MBq/10⁶ cells) for 72 h. Untreated cells were incubated in growth medium supplemented with DMSO (≤0.2%) for 72 h.

For cell culture dish assays, iCas9-MCF10A cells were seeded at 50,000–70,000 into 58-cm² dishes with complete culture medium. On day 7, cells were trypsinated and 50,000–100,000 of the cells replated into a new dish and cultured until collecting on day 12. For, 96-well plate assays, the cells were seeded at ~10,000 per well and cultured for 2–3 days until confluency, where after the cells were trypsinated and split 1:3, which was continued until collecting the cells at a confluent state. When indicated, cells were treated with 0.1% (vol/vol) DMSO vehicle or 2 nM talazoparib (Axon Medchem, 2502).

The following drugs were used: camptothecin (CPT), actinomycin D, cycloheximide, marizomib, chloroquine, Bmh21, BO-2, (all Sigma-Aldrich), aphidicolin (Santa Cruz), talazoparib (Axon Medchem), quarfloxin (CX-3543, Adooq Bioscience) and CX-5461 (Selleckchem).