Inhibition of WEE1 Potentiates Sensitivity to PARP Inhibitor in Biliary Tract Cancer
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Published on: August 21, 2013
Hye-Rim Seo1,2, Ah-Rong Nam1, Ju-Hee Bang1
1Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea.
Purpose:
Up to 20% of patients with biliary tract cancer (BTC) have alterations in DNA damage response (DDR) genes, including homologous recombination (HR) genes. Therefore, the DDR pathway could be a promising target for new drug development in BTC. We aim to investigate the anti-tumor effects using poly(ADP-ribose) polymerase (PARP) and WEE1 inhibitors in BTC.
Materials And Methods:
We used 10 BTC cell lines to evaluate an anti-tumor effect of olaparib (a PARP inhibitor) and AZD1775 (a WEE1 inhibitor) in in vitro. Additionally, we established SNU869 xenograft model for in vivo experiments.
Results:
In this study, we observed a modest anti-proliferative effect of olaparib. DNA double-strand break (DSB) and apoptosis were increased by olaparib in BTC cells. However, olaparib-induced DNA DSB was repaired through the HR pathway, and G2 arrest was induced to secure the time for repair. As AZD1775 typically regulates the G2/M checkpoint, we combined olaparib with AZD1775 to abrogate G2 arrest. We observed that AZD1775 downregulated p-CDK1, a G2/M cell cycle checkpoint protein, and induced early mitotic entry. AZD1775 also decreased CtIP and RAD51 expression and disrupted HR repair. In xenograft model, olaparib plus AZD1775 treatment reduced tumor growth more potently than did monotherapy with either drug.
Conclusion:
This is the first study to suggest that olaparib combined with AZD1775 can induce synergistic anti-tumor effects against BTC. Combination therapy that blocks dual PARP and WEE1 has the potential to be further clinically developed for BTC patients.
Insights
Combining PARP and WEE1 inhibitors shows synergistic anti-tumor effects in biliary tract cancer (BTC). This dual-action therapy, using olaparib and AZD1775, offers a promising new treatment strategy for BTC patients.
Area of Science:
- Oncology
- Molecular Biology
- Cancer Therapeutics
Background:
- Biliary tract cancer (BTC) exhibits DNA damage response (DDR) gene alterations in up to 20% of patients.
- The DDR pathway, including homologous recombination (HR) genes, presents a potential therapeutic target for BTC drug development.
Purpose of the Study:
- To investigate the anti-tumor efficacy of combining poly(ADP-ribose) polymerase (PARP) inhibitor olaparib with WEE1 inhibitor AZD1775 in BTC.
- To evaluate the effects of these inhibitors on DNA damage, cell cycle progression, and HR repair mechanisms in BTC models.
Main Methods:
- In vitro evaluation of olaparib and AZD1775 on 10 BTC cell lines.
- In vivo assessment using a SNU869 xenograft model.
- Analysis of DNA double-strand breaks (DSB), apoptosis, G2/M checkpoint regulation, and HR repair proteins (CtIP, RAD51).
Main Results:
- Olaparib demonstrated modest anti-proliferative effects, increasing DSB and apoptosis, but HR pathway mediated repair and G2 arrest.
- AZD1775 abrogated olaparib-induced G2 arrest by downregulating p-CDK1, inducing early mitotic entry, and disrupting HR repair by decreasing CtIP and RAD51.
- Combination therapy significantly reduced tumor growth in xenograft models compared to monotherapy.
Conclusions:
- This study is the first to demonstrate synergistic anti-tumor effects of combining olaparib and AZD1775 in BTC.
- Dual blockade of PARP and WEE1 presents a potential clinical development strategy for biliary tract cancer treatment.
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