pf-477736 and Pancreatic-Neoplasms

To develop effective combination therapy against pancreatic ductal adenocarcinoma (PDAC) with a combination of chemotherapy, CHK1 inhibition, and EGFR-targeted radioimmunotherapy.. Maximum tolerated doses were determined for the combination of gemcitabine, the CHK1 inhibitor PF-477736, and Lutetium-177 ((177)Lu)-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 (177)Lu-anti-EGFR antibody, survival of tumor-initiating cells, induction of DNA damage, cell death, and tumor tissue degeneration.. The combination of gemcitabine and CHK1 inhibitor PF-477736 with (177)Lu-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.. Our study developed an effective combination therapy against PDAC that has potential in the treatment of PDAC.

Topics: Animals; Antibodies, Monoclonal; Antimetabolites, Antineoplastic; Apoptosis; Benzodiazepinones; Blotting, Western; Carcinoma, Pancreatic Ductal; Cell Proliferation; Checkpoint Kinase 1; Combined Modality Therapy; Deoxycytidine; DNA Damage; Drug Synergism; ErbB Receptors; Female; Gemcitabine; Humans; Immunoenzyme Techniques; Mice; Mice, Inbred BALB C; Mice, Inbred NOD; Mice, SCID; Pancreatic Neoplasms; Phosphorylation; Protein Kinases; Pyrazoles; Radioimmunotherapy; Signal Transduction; Tumor Cells, Cultured; Xenograft Model Antitumor Assays