The Cellular and Biological Impact of Extracellular Vesicles in Pancreatic Cancer

Peripheral Nerve Decellularization for In Vitro Extracellular Matrix Hydrogel Use: A Comparative Study

The rise of tissue-engineered biomaterials has introduced more clinically translatable models of disease, including three-dimensional (3D) decellularized extracellular matrix (dECM) hydrogels. Specifically, decellularized nerve hydrogels have been utilized to model peripheral nerve injuries and disorders in vitro; however, there lacks standardization in decellularization methods. Here, rat sciatic nerves of varying preparations were decellularized using previously established methods: sodium deoxycholate (SD)-based, 3-((3-cholamidopropyl)dimethylammonio)-1-propanesulfonate (CHAPS)-based, and apoptosis-mediated. These nerves were characterized for cellular debris removal, ECM retention, and low cytotoxicity with cultured Schwann cells. The best preparations of each decellularization method were digested into dECM hydrogels, and rheological characterization, gelation kinetics, and confocal reflectance imaging of collagen fibril assembly were performed. It was determined that the SD-based method with nerve epineurial removal best maintained the overall ECM composition and mechanical properties of physiological peripheral nerves while efficiently stripping the scaffolds of tissue-specific cells and debris. This method was then utilized as a culture platform for quiescent Schwann cells and cancer-nerve crosstalk. Hydrogel-embedded Schwann cells were found to have high viability and act in a more physiologically relevant manner than those cultured in monolayers, and the hydrogel platform allowed for the activation of Schwann cells following treatment with cancer secreted factors. These findings establish a standard for peripheral nerve decellularization for usage as a dECM hydrogel testbed for in vitro peripheral nerve disease modeling and may facilitate the development of treatments for peripheral nerve disease and injury.

ANXA1 Contained in EVs Regulates Macrophage Polarization in Tumor Microenvironment and Promotes Pancreatic Cancer Progression and Metastasis

The tumor microenvironment (TME) is a dynamic system where nontumor and cancer cells intercommunicate through soluble factors and extracellular vesicles (EVs). The TME in pancreatic cancer (PC) is critical for its aggressiveness and the annexin A1 (ANXA1) has been identified as one of the oncogenic elements. Previously, we demonstrated that the autocrine/paracrine activities of extracellular ANXA1 depend on its presence in EVs. Here, we show that the complex ANXA1/EVs modulates the macrophage polarization further contributing to cancer progression. The EVs isolated from wild type (WT) and ANXA1 knock-out MIA PaCa-2 cells have been administrated to THP-1 macrophages finding that ANXA1 is crucial for the acquisition of a protumor M2 phenotype. The M2 macrophages activate endothelial cells and fibroblasts to induce angiogenesis and matrix degradation, respectively. We have also found a significantly increased presence of M2 macrophage in mice tumor and liver metastasis sections previously obtained by orthotopic xenografts with WT cells. Taken together, our data interestingly suggest the relevance of ANXA1 as potential diagnostic/prognostic and/or therapeutic PC marker.

Role of non-coding RNAs in tumor progression and metastasis in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal types of cancer with an overall 5-year survival rate of less than 10%. The 1-year survival rate of patients with locally advanced or metastatic disease is abysmal. The aggressive nature of cancer cells, hypovascularization, extensive desmoplastic stroma, and immunosuppressive tumor microenvironment (TME) endows PDAC tumors with multiple mechanisms of drug resistance. With no obvious genetic mutation(s) driving tumor progression or metastatic transition, the challenges for understanding the biological mechanism(s) of these processes are paramount. A better understanding of the molecular and cellular mechanisms of these processes could lead to new diagnostic tools for patient management and new targets for therapeutic intervention. microRNAs (miRNAs) are an evolutionarily conserved gene class of short non-coding regulatory RNAs. miRNAs are an extensive regulatory layer that controls gene expression at the posttranscriptional level. This review focuses on preclinical models that functionally dissect miRNA activity in tumor progression or metastatic processes in PDAC. Collectively, these studies suggest an influence of miRNAs and RNA-RNA networks in the processes of epithelial to mesenchymal cell transition and cancer cell stemness. At a cell-type level, some miRNAs mainly influence cancer cell–intrinsic processes and pathways, whereas other miRNAs predominantly act in distinct cellular compartments of the TME to regulate fibroblast and immune cell functions and/or influence other cell types’ function via cell-to-cell communications by transfer of extracellular vesicles. At a molecular level, the influence of miRNA-mediated regulation often converges in core signaling pathways, including TGF-β, JAK/STAT, PI3K/AKT, and NF-κB.