Abstract A022: Disrupting redox homeostasis initiates anti-tumor immune responses in pancreatic cancer
Bibliographic record
Abstract
Abstract Although immune therapy has made impressive progress in cancer treatment, pancreatic ductal adenocarcinoma (PDAC) remains an exception, likely due to its immunosuppressive tumor microenvironment that prevents immune responses against the tumor. Our current work aims to reactivate the suppressive immune infiltrate using radiation therapy and oxidative stress to potentiate antitumor immune responses in PDAC. Our lab previously found that PDAC cells are dependent on the antioxidant peroxiredoxin-4 (PRDX4) expression. PRDX4 prevents excessive levels of reactive oxygen species in cells and while high PRDX4 expression is associated with a more aggressive disease, it is dispensable in normal tissue. As such, disrupting redox homeostasis by inhibiting PRDX4 represents a targetable vulnerability in cancer cells. To investigate the radio-sensitizing potential of PRDX4, we knocked-down (KD) PRDX4 in human pancreatic tumor cells as well as in mouse cancer cells obtained from the spontaneous KPC model (driven by the KRas and P53 mutations), in combination with radiation. Presence and quantification of DNA damage were performed by immunofluorescence, and impaired cell survival was analyzed by clonogenic assays. Changes in immune secretion were assessed by RT-qPCR and Elisa and in vitro macrophage phenotyping was performed upon exposure to tumor cell conditioned media. Our data so far show an accumulation of cytosolic DNA upon PRDX4 KD in PDAC cells, with the presence of micronuclei as well as less aggregated DNA. Interestingly, targeting PRDX4 before radiation amplifies the release of radiation-induced cytosolic DNA while significantly decreasing cell growth and survival, compared to radiation alone. Cytosolic DNA has been shown to trigger innate immune signaling in tumor cells. Consistently, PRDX4 loss induces the upregulation of many pro-inflammatory genes, including CCL5, CCL20, and CXCL10, in a STING-dependent manner. Combining PRDX4 KD with radiation leads to a higher gene upregulation of these immune stimulatory chemokines, as well as an increased protein secretion within tumor cell media. These findings support an amplified immunomodulatory effect of radiation when combined with PRDX4 loss in PDAC cells. To assess whether targeting PRDX4 can remodel the tumor microenvironment, we applied tumor conditioned media from cancer cells on isolated naive mouse CD45+/CD11c+/F4/80+ macrophages. Media from cells treated with PRDX4 KD + radiation strongly increased the migration ability of macrophages while modulating the expression of a subset of chemokine-encoding genes in immune cells. Using the spontaneous KPC model depleted for PRDX4, along with syngeneic orthotopic models, we are now aiming to confirm this radio-sensitizing and immune-modulatory potential of PRDX4 in vivo. The aggressiveness of PDAC requires research towards novel treatment strategies and our data strongly support evidence for targeting cancer metabolism, particularly antioxidant systems, in synergy with existing cancer therapies, like radiation and immune therapy. Citation Format: Lucie Malbeteau, Emily Poulton, Vishal Pandya, Marianne Koritzinsky. Disrupting redox homeostasis initiates anti-tumor immune responses in pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr A022.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".