Gemcitabine and CHK1 inhibition potentiate EGFR-directed radioimmunotherapy against pancreatic ductal adenocarcinoma

Al-Ejeh, F. et al. (2014) Gemcitabine and CHK1 inhibition potentiate EGFR-directed radioimmunotherapy against pancreatic ductal adenocarcinoma. Clinical Cancer Research, 20(12), pp. 3187-3197. (doi:10.1158/1078-0432.CCR-14-0048) (PMID:24838526)

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Purpose: To develop effective combination therapy against pancreatic ductal adenocarcinoma (PDAC) with a combination of chemotherapy, CHK1 inhibition, and EGFR-targeted radioimmunotherapy.<p></p> Experimental Design: Maximum tolerated doses were determined for the combination of gemcitabine, the CHK1 inhibitor PF-477736, and Lutetium-177 (177Lu)–labeled anti-EGFR antibody. This triple combination therapy was investigated using PDAC models from well-established cell lines, recently established patient-derived cell lines, and fresh patient-derived xenografts. Tumors were investigated for the accumulation of 177Lu-anti-EGFR antibody, survival of tumor-initiating cells, induction of DNA damage, cell death, and tumor tissue degeneration.<p></p> Results: The combination of gemcitabine and CHK1 inhibitor PF-477736 with 177Lu-anti-EGFR antibody was tolerated in mice. This triplet was effective in established tumors and prevented the recurrence of PDAC in four cell line–derived and one patient-derived xenograft model. This exquisite response was associated with the loss of tumor-initiating cells as measured by flow cytometric analysis and secondary implantation of tumors from treated mice into treatment-naïve mice. Extensive DNA damage, apoptosis, and tumor degeneration were detected in the patient-derived xenograft. Mechanistically, we observed CDC25A stabilization as a result of CHK1 inhibition with consequent inhibition of gemcitabine-induced S-phase arrest as well as a decrease in canonical (ERK1/2 phosphorylation) and noncanonical EGFR signaling (RAD51 degradation) as a result of EGFR inhibition.<p></p> Conclusions: Our study developed an effective combination therapy against PDAC that has potential in the treatment of PDAC.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Grimmond, Professor Sean and Biankin, Professor Andrew
Authors: Al-Ejeh, F., Pajic, M., Shi, W., Kalimutho, M., Miranda, M., Nagrial, A. M., Chou, A., Biankin, A. V., Grimmond, S. M., Brown, M. P., and Khanna, K. K.
College/School:College of Medical Veterinary and Life Sciences > Institute of Cancer Sciences
Journal Name:Clinical Cancer Research
Publisher:American Association for Cancer Research
ISSN (Online):1557-3265

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