Abstract B109: Proteomics analysis of histotripsy ablated pancreatic tumors in C57BL/6 mice
Joshua L. Perez, Tamalika Paul, Irving Coy. AllenAbstract
Background:
Histotripsy is a non-invasive, non-thermal focused ultrasound ablation technology that mechanically disrupts tumor tissue while stimulating anti-tumor immune responses. Although histotripsy enhances immune cell infiltration and has demonstrated systemic immunologic effects, the mechanisms linking tumor destruction to adaptive immunity remain incompletely understood. We hypothesized that histotripsy alters major histocompatibility complex (MHC) class I antigen presentation and remodels the tumor immunopeptidome.
Methods:
Pan02 pancreatic tumors were established in C57BL/6 mice and treated with partial histotripsy ablation or left untreated as controls. Tumors were harvested 2 hours and 21 days following treatment. MHC-associated peptides were enriched using the semi-automated SAPrIm immunopeptidomics workflow and analyzed by liquid chromatography coupled with variable-window data-independent acquisition mass spectrometry. Peptide identification and quality-control analyses were performed using PEAKS software.
Results:
Twenty-two mass spectrometry analyses generated 413,653 frames, 282,397 precursor ions, 180,243 extracted features, and 68,966 peptide-spectrum matches, yielding 1,127 unique peptides derived from 40 proteins. Replicate analyses demonstrated reproducible peptide recovery across experimental conditions, supporting the robustness of the workflow. A conserved core immunopeptidome was identified across treatment groups, while additional peptide populations varied according to histotripsy treatment and collection time point. These treatment-associated peptide signatures suggest dynamic remodeling of antigen presentation following histotripsy. Chromatographic quality assessment also identified opportunities to improve peptide recovery and expand immunopeptidome coverage in future studies.
Conclusions:
Mass spectrometry-based immunopeptidomics is a feasible approach for characterizing antigen presentation following histotripsy in pancreatic cancer. These preliminary findings provide evidence that histotripsy remodels the MHC class I immunopeptidome and establish a foundation for mechanistic studies investigating how altered antigen presentation contributes to histotripsy-induced anti-tumor immunity and may inform future combination immunotherapy strategies.Generative AI was used to improve the clarity and organization of this abstract. All authors reviewed and verified the accuracy and integrity of the final submitted content.
Citation Format:
Joshua L. Perez, Tamalika Paul, Irving Coy. Allen. Proteomics analysis of histotripsy ablated pancreatic tumors in C57BL/6 mice [abstract]. In: Proceedings of the AACR Conference on Pancreatic Cancer: New Frontiers in Biology and Therapeutic Development; 2026 Sep 25-28; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(18_Suppl_2):Abstract nr B109.