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Updated: Aug 8, 2025
Yeast As a Chassis for Developing Functional Assays to Study Human P53
Published on: August 4, 2019
Multifaceted role for p53 in pancreatic cancer suppression
Stephano S Mello1,2, Brittany M Flowers1, Pawel K Mazur3
1Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305.
Abstract:
The vast majority of human pancreatic ductal adenocarcinomas (PDACs) harbor TP53 mutations, underscoring p53's critical role in PDAC suppression. PDAC can arise when pancreatic acinar cells undergo acinar-to-ductal metaplasia (ADM), giving rise to premalignant pancreatic intraepithelial neoplasias (PanINs), which finally progress to PDAC. The occurrence of TP53 mutations in late-stage PanINs has led to the idea that p53 acts to suppress malignant transformation of PanINs to PDAC. However, the cellular basis for p53 action during PDAC development has not been explored in detail. Here, we leverage a hyperactive p53 variant-p5353,54-which we previously showed is a more robust PDAC suppressor than wild-type p53, to elucidate how p53 acts at the cellular level to dampen PDAC development. Using both inflammation-induced and KRASG12D-driven PDAC models, we find that p5353,54 both limits ADM accumulation and suppresses PanIN cell proliferation and does so more effectively than wild-type p53. Moreover, p5353,54 suppresses KRAS signaling in PanINs and limits effects on the extracellular matrix (ECM) remodeling. While p5353,54 has highlighted these functions, we find that pancreata in wild-type p53 mice similarly show less ADM, as well as reduced PanIN cell proliferation, KRAS signaling, and ECM remodeling relative to Trp53-null mice. We find further that p53 enhances chromatin accessibility at sites controlled by acinar cell identity transcription factors. These findings reveal that p53 acts at multiple stages to suppress PDAC, both by limiting metaplastic transformation of acini and by dampening KRAS signaling in PanINs, thus providing key new understanding of p53 function in PDAC.
Insights
p53 suppresses pancreatic ductal adenocarcinoma (PDAC) by limiting metaplasia and proliferation. This study reveals p53
Area of Science:
- Oncology
- Molecular Biology
- Cell Biology
Background:
- Pancreatic ductal adenocarcinoma (PDAC) frequently harbors TP53 mutations, indicating p53's tumor suppressor role.
- PDAC development involves acinar-to-ductal metaplasia (ADM) and progression from pancreatic intraepithelial neoplasias (PanINs).
- The precise cellular mechanisms of p53's tumor suppression in PDAC remain incompletely understood.
Purpose of the Study:
- To elucidate the cellular functions of p53 in suppressing PDAC development.
- To investigate the role of a hyperactive p53 variant (p5353,54) in PDAC suppression.
- To understand how p53 influences key pathways like KRAS signaling and extracellular matrix remodeling during PDAC progression.
Main Methods:
- Utilized both inflammation-induced and KRASG12D-driven mouse models of PDAC.
- Compared the effects of a hyperactive p53 variant (p5353,54) with wild-type p53 and Trp53-null conditions.
- Analyzed acinar-to-ductal metaplasia (ADM), PanIN cell proliferation, KRAS signaling, and extracellular matrix (ECM) remodeling.
- Assessed p53's impact on chromatin accessibility at acinar cell identity transcription factor sites.
Main Results:
- The hyperactive p5353,54 variant more effectively limited ADM and suppressed PanIN cell proliferation than wild-type p53.
- p5353,54 suppressed KRAS signaling and attenuated ECM remodeling in PanINs.
- Wild-type p53 also demonstrated PDAC-suppressive functions, reducing ADM, PanIN proliferation, KRAS signaling, and ECM remodeling compared to Trp53-null pancreata.
- p53 was found to enhance chromatin accessibility at sites regulated by acinar cell identity transcription factors.
Conclusions:
- p53 acts at multiple stages to suppress PDAC, including limiting metaplasia and dampening KRAS signaling in PanINs.
- The study provides novel insights into the cellular mechanisms underlying p53's tumor suppressive functions in pancreatic cancer.
- Understanding p53's role offers potential avenues for therapeutic strategies targeting PDAC development.
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