Sequential Therapy with PARP and WEE1 Inhibitors Minimizes Toxicity while Maintaining Efficacy

Yong Fang, Daniel J. McGrail, Chaoyang Sun, Marilyne Labrie, Xiaohua Chen, Dong Zhang, Zhenlin Ju, Christopher P. Vellano, Yiling Lu, Yongsheng Li, Kang Jin Jeong, Zhiyong Ding, Jiyong Liang, Steven W. Wang, Hui Dai, Sanghoon Lee, Nidhi Sahni, Imelda Mercado-Uribe, Tae beom Kim, Ken ChenShiaw Yih Lin, Guang Peng, Shannon N. Westin, Jinsong Liu, Mark J. O'Connor, Timothy A. Yap, Gordon B. Mills

Research output: Contribution to journalArticlepeer-review

112 Scopus citations


We demonstrate that concurrent administration of poly(ADP-ribose) polymerase (PARP) and WEE1 inhibitors is effective in inhibiting tumor growth but poorly tolerated. Concurrent treatment with PARP and WEE1 inhibitors induces replication stress, DNA damage, and abrogates the G2 DNA damage checkpoint in both normal and malignant cells. Following cessation of monotherapy with PARP or WEE1 inhibitors, effects of these inhibitors persist suggesting that sequential administration of PARP and WEE1 inhibitors could maintain efficacy while ameliorating toxicity. Strikingly, while sequential administration mirrored concurrent therapy in cancer cells that have high basal replication stress, low basal replication stress in normal cells protected them from DNA damage and toxicity, thus improving tolerability while preserving efficacy in ovarian cancer xenograft and patient-derived xenograft models. Fang et al. show that sequential inhibition of PARP (PARPi) and WEE1 or ATR has antitumor efficacy similar to concurrent treatment but reduced toxicity due to the persistence of DNA damage on removal of PARPi and differences in basal replication stress between tumor and normal cells, respectively.

Original languageEnglish (US)
Pages (from-to)851-867.e7
JournalCancer Cell
Issue number6
StatePublished - Jun 10 2019


  • PARP inhibitor
  • WEE1 inhibitor
  • replication stress
  • sequential therapy

ASJC Scopus subject areas

  • Oncology
  • Cell Biology
  • Cancer Research


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