Abstract 5333: Pancreatic cancer enhances HER2 signaling through DUSP6 to circumvent therapeutic MAPK inhibition
Bibliographic record
Abstract
Abstract Background: Oncogenic KRAS is present in almost all cases of pancreatic ductal adenocarcinoma (PDAC). However, targeting KRAS or its canonical signaling cascades, especially the mitogen-activated protein kinase (MAPK) pathway, remains clinically unsuccessful. Targeting ERK kinases has recently emerged as a promising therapeutic strategy and combinatorial strategies should be developed. Aim: Identify adaptive mechanisms to ERK inhibition that can be co-targeted to achieve effective tumor inhibition in multiple patient-derived xenograft (PDX) models. Methods: Reverse-phase protein array (RPPA) was used in early-passage patient-derived cell lines (PDCLs) to identify potential resistance mechanisms. These were confirmed using RNA interference and overexpression in PDAC cell lines and PDCLs. The promising combinations were tested in 30 early-passaged PDAC PDXs. Results: RPPA showed dramatic downregulation of DUSP4 and DUSP6 phosphatases following MEK and ERK inhibition, which coincided with upregulation of phospho-HER2 and -HER3. Knockdown of DUSP6, but not DUSP4, was sufficient in phosphorylation of HER2. Conversely, overexpression of DUSP6 curbed HER2 and ERK activation. Downregulation of DUSP4 and DUSP6 induced by ulixertinib, an ERK inhibitor now in clinical development, was reversed by bortezomib, suggesting DUSP4 and DUSP6 are proteosomally degraded. Combined ulixertinib plus PI3K inhibitor copanlisib, or pan-HER inhibitor afatinib slowed but did not arrest PDX tumor growth in vivo, and addition of gemcitabine was required to achieve tumor regression or durable growth arrest. Alternatively, ulixertinib or MEK inhibitor (trametinib) in combination with trastuzumab deruxtecan (DS-8201a), an anti-HER2 conjugated topoisomerase I inhibitor, were extremely effective, leading to complete and durable tumor regression for all tested PDX models. We showed that upregulation of HER2 expression following MEK or ERK inhibitor treatment provides a conduit for enhanced internalization of DS-8201a. Conclusions: Our study provided novel mechanistic insight on how PDAC cells evade MAPK inhibition via enhancing HER2 signaling. We demonstrated that the combination of MEK or ERK inhibitor plus DS-8201a is extremely effective, leading to complete tumor regression in multiple PDAC PDX models. This combination should be advanced as a clinical trial for PDAC patients. Keys: DS-8201a, DUSP6, HER2, KRAS, ulixertinib, pancreatic ductal adenocarcinoma Citation Format: Ashenafi Shiferaw Bulle, Kuljeet Seehar, Sapana Bansod, Yali Chen, Chen Hung-Po, Paarth B. Dodhiawala, Lin Li, Vikas Somani, Jacqueline Mudd, Ryan C. Fields, Deborah Knoerzer, Andrea Wang-Gillam, Lim Kian-Huat. Pancreatic cancer enhances HER2 signaling through DUSP6 to circumvent therapeutic MAPK inhibition [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5333.
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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".