Pancreatic cancer tumor microenvironment: composition, ECM remodeling, and therapeutic targets

Introduction and clinical significance of PDAC

Pancreatic cancer, most commonly represented by Pancreatic Ductal Adenocarcinoma (PDAC), remains among the deadliest malignancies. Unlike several other cancers where prevention, early detection, and therapy have reduced mortality, PDAC is frequently diagnosed at advanced stages and carries a poor prognosis. The limited efficacy of current therapies and persistently high mortality underline an urgent need for novel and effective treatment strategies.

A core obstacle to therapeutic progress in PDAC is the unique and highly complex tumor microenvironment (TME). The TME is not a passive scaffold but an active participant in tumor biology, influencing metabolism, immune infiltration, metastatic potential, and response to treatment.

Key cellular components of the PDAC tumor microenvironment

The PDAC TME comprises multiple interacting cellular populations. Prominent among these are cancer-associated fibroblasts (CAFs), which contribute to stromal deposition and remodelling. Immunosuppressive immune cells within the TME limit effective antitumor immune responses. Cancer stem cells are implicated in tumor initiation, heterogeneity, and resistance. Together, these cellular components interact with the noncellular matrix to sustain tumor growth and influence phenotype.

Composition and remodeling of the extracellular matrix in PDAC

The noncellular scaffold of PDAC, the extracellular matrix (ECM) or matrisome, undergoes substantial remodeling during the transition from normal pancreas to malignant PDAC. Remodeling is characterized by progressive alterations in abundance, composition, organization, and complexity of ECM proteins.

Key features of ECM remodeling in PDAC described in the source include:

• Increased deposition of structural ECM proteins, notably various collagens, contributing to a dense stromal reaction (desmoplasia).
• Enhanced activity of ECM-modifying enzymes, including hyaluronidases and matrix metalloproteinases (MMPs), which modify matrix composition and organization.
• Reorganization of matrisome components that changes biochemical signaling and mechanical properties of the tumor niche.

These matrix-level changes create a structural and biochemical scaffold that supports malignant phenotypes and modulates interactions among tumor and stromal cells.

Molecular pathways driving stromal activation and ECM changes

Tumor-promoting signaling cascades are central drivers of stromal activation and ECM remodeling in PDAC. The review highlights the role of TGF-β signaling in promoting stromal activation, matrix remodeling, and desmoplasia. Other cancer-associated pathways implicated include RAS and PI3K/AKT/mTOR signaling cascades, as well as ABCG2-related pathways. Collectively, these signaling mechanisms influence ECM composition, tumor progression, and therapeutic resistance.

Consequences of a remodeled ECM: desmoplasia, stiffness, and therapy resistance

ECM remodeling in PDAC generates multiple functional consequences relevant to disease biology and treatment:

• Desmoplasia and increased tissue stiffness alter tumor biomechanics and cellular behavior.
• The dense ECM impairs effective drug delivery by creating physical barriers to penetration and modifying interstitial pressures.
• ECM-driven changes contribute to immune exclusion, limiting infiltration and function of antitumor immune cells.
• Matrix remodeling supports metabolic adaptations and pathways associated with therapeutic resistance and aggressive tumor phenotypes.

These interrelated effects position the remodeled ECM as a major determinant of PDAC aggressiveness and a key barrier to treatment efficacy.

ECM-associated therapeutic targets and strategies

Given the central contribution of the ECM and stromal compartments to PDAC biology and resistance, multiple therapeutic strategies aim to target or reprogram the stroma. Approaches discussed in the source include targeting:

• Hyaluronan metabolism to alter ECM hydration, viscosity, and interstitial pressure.
• Collagen deposition or crosslinking to reduce matrix density and stiffness.
• TGF-β signaling to limit stromal activation and desmoplastic remodeling.
• Focal adhesion and other ECM-interacting pathways to disrupt tumor–matrix signaling.
• ECM-modifying enzymes such as hyaluronidases and MMPs, which directly change matrix composition.

The source indicates that these ECM-associated components and signaling pathways have been explored in preclinical models and in clinical trials, with a translational focus on improving drug delivery, overcoming immune exclusion, and reducing therapy resistance. Specific trial results or quantitative outcomes were not reported in the abstract-level content provided.

Figures summarizing ECM remodeling and therapeutic targets

The review includes figures that summarize (1) the remodeling and composition of the ECM in PDAC — depicting progressive matrisome changes, increased structural protein deposition, elevated ECM-modifying enzyme activity, and involvement of tumor-promoting signaling — and (2) ECM-associated therapeutic targets explored in preclinical and clinical settings, including hyaluronan-, collagen-, TGF-β- and focal adhesion–directed strategies.

Conclusions and translational implications

The remodelled ECM is central to PDAC pathophysiology, shaping mechanical and biochemical features that support tumor progression, immune evasion, and therapeutic resistance. The review highlights the ECM and its regulatory pathways as compelling translational targets. Efforts to modulate hyaluronan metabolism, collagen architecture, TGF-β signaling, focal adhesion pathways, and ECM-modifying enzymes represent active areas of preclinical and clinical investigation aimed at reprogramming the TME to improve therapeutic outcomes in PDAC.

Note: The source material summarized here is the abstract and figure captions from the cited review. Detailed experimental data, specific clinical trial outcomes, and quantitative results were not reported in the provided source text.