TY - JOUR
T1 - Coordinately targeting cell-cycle checkpoint functions in integrated models of pancreatic cancer
AU - Chung, Sejin
AU - Vail, Paris
AU - Witkiewicz, Agnieszka K.
AU - Knudsen, Erik S.
N1 - Funding Information:
The authors thank members of the Witkiewicz and Knudsen laboratories for technical assistance and discussion of study results. This study was supported by grants from the NIH. Services were provided by the Flow and Image Cytometry Core facility, Pathology Network Shared Resource, and Translational Imaging Shared Resource, which are supported by the Roswell Park Cancer Center (NCI P30CA16056).
Publisher Copyright:
© 2018 American Association for Cancer Research.
PY - 2019/4/1
Y1 - 2019/4/1
N2 - Purpose: Cancer cells often have deficiencies in cell-cycle control mechanisms and could be dependent on specific cell-cycle checkpoints to maintain viability. Because of the documented role of KRAS in driving replication stress, we targeted the checkpoint governing DNA replication using CHK1 kinase inhibitors in pancreatic ductal adenocarcinoma (PDAC) models and examined mechanisms of resistance. Experimental Design: Single-agent efficacy of CHK1 inhibition was investigated in established and primary PDAC lines. Drug screening was performed to identify cooperative agents. In vitro and in vivo studies were employed to interrogate combination treatment efficacy and mechanisms of resistance. Results: Many PDAC models evade single-agent inhibition through mechanisms that allow S-phase progression with CHK1 inhibited. Gene expression analysis revealed FOXM1 as a potential marker of CHK1 sensitivity and defined a form of pancreatic cancer with poor prognosis. Drug screen analysis identified WEE1 as a cooperative agent with CHK1 and was effective in cell culture. In vivo experiments validated the combination efficacy; however, resistance could evolve. Resistance was due to selection of a stable subclone from the original PDX tumor, which harbored high baseline replication stress. In vitro analysis revealed that gemcitabine could eliminate viability in the resistant models. The triplet regimen of gemcitabine, CHK1, and WEE1 inhibition provided strong disease control in all xenograft models interrogated. Conclusions: These results demonstrate the therapeutic resiliency of pancreatic cancer and indicate that coordinately targeting cell-cycle checkpoints in concert with chemotherapy could be particularly efficacious.
AB - Purpose: Cancer cells often have deficiencies in cell-cycle control mechanisms and could be dependent on specific cell-cycle checkpoints to maintain viability. Because of the documented role of KRAS in driving replication stress, we targeted the checkpoint governing DNA replication using CHK1 kinase inhibitors in pancreatic ductal adenocarcinoma (PDAC) models and examined mechanisms of resistance. Experimental Design: Single-agent efficacy of CHK1 inhibition was investigated in established and primary PDAC lines. Drug screening was performed to identify cooperative agents. In vitro and in vivo studies were employed to interrogate combination treatment efficacy and mechanisms of resistance. Results: Many PDAC models evade single-agent inhibition through mechanisms that allow S-phase progression with CHK1 inhibited. Gene expression analysis revealed FOXM1 as a potential marker of CHK1 sensitivity and defined a form of pancreatic cancer with poor prognosis. Drug screen analysis identified WEE1 as a cooperative agent with CHK1 and was effective in cell culture. In vivo experiments validated the combination efficacy; however, resistance could evolve. Resistance was due to selection of a stable subclone from the original PDX tumor, which harbored high baseline replication stress. In vitro analysis revealed that gemcitabine could eliminate viability in the resistant models. The triplet regimen of gemcitabine, CHK1, and WEE1 inhibition provided strong disease control in all xenograft models interrogated. Conclusions: These results demonstrate the therapeutic resiliency of pancreatic cancer and indicate that coordinately targeting cell-cycle checkpoints in concert with chemotherapy could be particularly efficacious.
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U2 - 10.1158/1078-0432.CCR-18-1620
DO - 10.1158/1078-0432.CCR-18-1620
M3 - Article
C2 - 30538111
AN - SCOPUS:85064183739
SN - 1078-0432
VL - 25
SP - 2290
EP - 2304
JO - Clinical Cancer Research
JF - Clinical Cancer Research
IS - 7
ER -