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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, RESULTS. Meshes: Animals, Antineoplastic Agents, Apoptosis, Blotting, Western, Carcinoma, Pancreatic Ductal, Cell Cycle, Cell Movement, Cell Proliferation, Drug Synergism, ErbB Receptors, Erlotinib Hydrochloride, Fluorescent Antibody Technique, Humans, Immunoenzyme Techniques, Mice, Mice, Inbred NOD, Mice, SCID, Pancreatic Neoplasms, Phosphatidylinositol 3-Kinases, Phosphorylation, Protein Kinase Inhibitors, Proto-Oncogene Proteins c-akt, Pyrimidines, Pyrroles, Quinazolines, RNA, Messenger, Real-Time Polymerase Chain Reaction, Reverse Transcriptase Polymerase Chain Reaction, Signal Transduction, Thiazoles, Tumor Cells, Cultured, Xenograft Model Antitumor Assays.
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Does cotargeting of epidermal growth factor receptor and PI3K overcome PI3K-Akt oncogenic dependence in pancreatic ductal adenocarcinoma? Context: PI3K-Akt is overexpressed in 50% to 70% of pancreatic ductal adenocarcinoma (PDAC). The hypothesis of this study is that PI3K and EGFR coinhibition may be effective in PDAC with upregulated PI3K-Akt signaling. Multiple inhibitors were tested on five PDAC cell lines. EGFR inhibitor (EGFRi)-resistant cell lines were found to have significantly overexpressed AKT2 gene, total Akt, and pAkt. In vitro erlotinib-resistant (ER) cell models (BxPC-ER and PANC-ER) with highly constitutively active PI3K-Akt were developed. These and their respective parent cell lines were tested for sensitivity to erlotinib, IGFIR inhibitor NVP-AEW541 (AEW), and PI3K-alpha inhibitor NVP-BYL719 (BYL), alone or in combination, by RTK-phosphoarray, Western blotting, immunofluorescence, qRT-PCR, cell proliferation, cell cycle, clonogenic, apoptosis, and migration assays. Erlotinib plus BYL was tested in vivo. Erlotinib acted synergistically with BYL in BxPC-ER (synergy index, SI = 1.71) and PANC-ER (SI = 1.44). Treatment of ER cell lines showing upregulated PI3K-Akt with erlotinib plus BYL caused significant G1 cell-cycle arrest (71%, P < 0.001; 58%, P = 0.003), inhibition of colony formation (69% and 72%, both P < 0.001), and necrosis and apoptosis (75% and 53%, both P < 0.001), more so compared with parent cell lines. In primary patient-derived tumor subrenal capsule (n = 90) and subcutaneous (n = 22) xenografts, erlotinib plus BYL significantly reduced tumor volume (P = 0.005). Strong pEGFR and pAkt immunostaining (2+/3+) was correlated with high and low responses, respectively, to both erlotinib and erlotinib plus BYL.
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PDAC with increased expression of the PI3K-Akt pathway was susceptible to PI3K-EGFR coinhibition, suggesting oncogenic dependence. Erlotinib plus BYL should be considered for a clinical study in PDAC; further evaluation of pEGFR and pAkt expression as potential positive and negative predictive biomarkers is warranted. Final Decision: yes