Transcription termination counteracts DNA damage after WEE1 inhibition

Transcription termination is a key regulatory step in transcription and a potential target for cancer therapy, but how it can be exploited for treatment is incompletely understood. Here we show that transcription termination plays a crucial role in mitigating DNA damage and cell death upon WEE1 inhibition by adavosertib. Depleting five different transcription termination factors (WDR82, PNUTS, XRN2, DDX5 or CPSF73) increased adavosertib-induced DNA damage in S-phase. Conversely, inhibiting active transcription with DRB or triptolide, or co-depleting CDC73, a component of the PAF1 transcription elongation complex, reduced such damage. Additionally, read-through transcription following WDR82 depletion was partially inhibited by co-depletion of CDC73, supporting that read-through transcription contributes to DNA damage in response to WEE1 inhibition. Moreover, combining adavosertib with the CPSF73 inhibitor JTE-607, an anticancer compound which promotes read-through transcription, increased DNA damage during S-phase. Elevated expression of CPSF73 is associated with aggressive disease in prostate cancer patients, and combining JTE-607 with adavosertib synergistically reduced prostate cancer cell survival. Our findings suggest that transcription termination helps prevent toxic conflicts between transcription and replication following increased replication initiation caused by WEE1 inhibition.