Pancreatic Adenocarcinoma Invasiveness and the Tumor Microenvironment: From Biology to Clinical Trials

INPP4B promotes PDAC aggressiveness via PIKfyve and TRPML-1-mediated lysosomal exocytosis

Aggressive solid malignancies, including pancreatic ductal adenocarcinoma (PDAC), can exploit lysosomal exocytosis to modify the tumor microenvironment, enhance motility, and promote invasiveness. However, the molecular pathways through which lysosomal functions are co-opted in malignant cells remain poorly understood. In this study, we demonstrate that inositol polyphosphate 4-phosphatase, Type II (INPP4B) overexpression in PDAC is associated with PDAC progression. We show that INPP4B overexpression promotes peripheral dispersion and exocytosis of lysosomes resulting in increased migratory and invasive potential of PDAC cells. Mechanistically, INPP4B overexpression drives the generation of PtdIns(3,5)P2 on lysosomes in a PIKfyve-dependent manner, which directs TRPML-1 to trigger the release of calcium ions (Ca2+). Our findings offer a molecular understanding of the prognostic significance of INPP4B overexpression in PDAC through the discovery of a novel oncogenic signaling axis that orchestrates migratory and invasive properties of PDAC via the regulation of lysosomal phosphoinositide homeostasis.

E3 ubiquitin ligase FBXW11 as a novel inflammatory biomarker is associated with immune infiltration and NF-κB pathway activation in pancreatitis and pancreatic cancer

BACKGROUND

Pancreatic cancer (pancreatic ductal adenocarcinoma, PDAC) is an aggressive disease with an overall poor prognosis. Pancreatitis is a major risk factor for the development of PDAC. Due to the lack of reliable and accurate biomarkers, the diagnosis, treatment, and prognosis of PDAC face great challenges. It is of great significance to elucidate the pathogenesis of PDAC and explore novel inflammatory biomarkers.

METHODS

We identified E3 ubiquitin ligases associated with pancreatic inflammation by combining multiple GEO datasets and UbiNet 2.0, and integrating the WGCNA algorithm and Limma R package. A risk score model for PDAC patients was established by using LASSO regression. We investigated the correlation between FBXW11 and immune cell infiltration using CIBERSORT, mMCP-counter, ImmuCellAI-mouse, QUANTISEQ, and TIMER algorithms, based on GEO, ArrayExpress, and TCGA datasets. We used Ubibrowser 2.0 to predict potential substrates for FBXW11. WikiPathway, MSigDB Hallmark, and Elsevier pathway analysis of FBXW11 key substrates were also performed using the EnrichR database. We detected protein expression through IHC, immunofluorescence, and western blot in the cerulein-induced acute pancreatitis mouse model.

RESULTS

We first identified that FBXW11 exhibited a clear tendency to gradually increase in normal, pancreatitis, and PDAC patients. The validation analysis revealed that the FBXW11 protein exhibited significantly high expression in cerulein-induced acute pancreatitis mice, with its distribution primarily observed in the cytoplasm. Simultaneously, we developed a risk model utilizing the genes associated with FBXW11 to forecast the outcome of patients with PDAC and the likelihood of pancreatitis advancing to pancreatic cancer. Functional analysis showed that FBXW11, as a novel inflammatory biomarker, had a significant positive correlation with macrophage infiltration and the NF-κB signaling pathway. Finally, the western blot assay of the NF-κB signaling pathway in pancreatic tissues demonstrated that high activation of NF-κB was correlated with high expression of FBXW11.

CONCLUSIONS

Our research not only provides evidence for FBXW11 as a novel inflammatory biomarker but also provides new insights into the research and clinical treatment of pancreatic cancer.

Cellular metabolism in pancreatic cancer as a tool for prognosis and treatment (Review)

Pancreatic cancer (PC) has one of the highest fatality rates and the currently available therapeutic options are not sufficient to improve its overall poor prognosis. In addition to insufficient effectiveness of anticancer treatments, the lack of clear early symptoms and early metastatic spread maintain the PC survival rates at a low level. Metabolic reprogramming is among the hallmarks of cancer and could be exploited for the diagnosis and treatment of PC. PC is characterized by its heterogeneity and, apart from molecular subtypes, the identification of metabolic subtypes in PC could aid in the development of more individualized therapeutic approaches and may lead to improved clinical outcomes. In addition to the deregulated utilization of glucose in aerobic glycolysis, PC cells can use a wide range of substrates, including branched‑chain amino acids, glutamine and lipids to fulfil their energy requirements, as well as biosynthetic needs. The tumor microenvironment in PC supports tumor growth, metastatic spread, treatment resistance and the suppression of the host immune response. Moreover, reciprocal interactions between cancer and stromal cells enhance their metabolic reprogramming. PC stem cells (PCSCs) with an increased resistance and distinct metabolic properties are associated with disease relapses and cancer spread, and represent another significant candidate for therapeutic targeting. The present review discusses the metabolic signatures observed in PC, a disease with a multifaceted and often transient metabolic landscape. In addition, the metabolic pathways utilized by PC cells, as well as stromal cells are discussed, providing examples of how they could present novel targets for therapeutic interventions and elaborating on how interactions between the various cell types affect their metabolism. Furthermore, the importance of PCSCs is discussed, focusing specifically on their metabolic adaptations.

Message in hand: the application of CRISPRi, RNAi, and LncRNA in adenocarcinoma

Gene editing interference technology has been flourishing for more than 30 years. It has always been a common means to interfere with the expression of particular genes. Today it has shown a broad application prospect in clinical treatment, especially in adenocarcinoma treatment. In just a few years, the CRISPRi technology has attracted much z attention with its precise targeting and convenient operability significantly promoted the transformation from bench to bedside, and won the Nobel Prize in Chemistry 2020. In recent years, the importance of non-coding RNA has led LncRNA research to the center. At the same time, it also recalls the surprises obtained in laboratory and clinic research by RNAi technologies such as microRNA, siRNA, and shRNA at the beginning of the century. Therefore, this article focuses on CRISPRi, RNAi, and LncRNA to review their gene interference mechanisms currently expected to be translational research. Their applications and differences in adenocarcinoma research will also be described powerfully. It will provide a helpful reference for scientists to understand better and apply several RNA interference technologies.

Noncoding RNAs Associated with Therapeutic Resistance in Pancreatic Cancer

Therapeutic resistance is an inevitable impediment towards effective cancer therapies. Evidence accumulated has shown that the signaling pathways and related factors are fundamentally responsible for therapeutic resistance via regulating diverse cellular events, such as epithelial-to-mesenchymal transition (EMT), stemness, cell survival/apoptosis, autophagy, etcetera. Noncoding RNAs (ncRNAs) have been identified as essential cellular components in gene regulation. The expression of ncRNAs is altered in cancer, and dysregulated ncRNAs participate in gene regulatory networks in pathological contexts. An in-depth understanding of molecular mechanisms underlying the modulation of therapeutic resistance is required to refine therapeutic benefits. This review presents an overview of the recent evidence concerning the role of human ncRNAs in therapeutic resistance, together with the feasibility of ncRNAs as therapeutic targets in pancreatic cancer.

Molecular Changes Underlying Hypertrophic Scarring Following Burns Involve Specific Deregulations at All Wound Healing Stages (Inflammation, Proliferation and Maturation)

Excessive connective tissue accumulation, a hallmark of hypertrophic scaring, results in progressive deterioration of the structure and function of organs. It can also be seen during tumor growth and other fibroproliferative disorders. These processes result from a wide spectrum of cross-talks between mesenchymal, epithelial and inflammatory/immune cells that have not yet been fully understood. In the present review, we aimed to describe the molecular features of fibroblasts and their interactions with immune and epithelial cells and extracellular matrix. We also compared different types of fibroblasts and their roles in skin repair and regeneration following burn injury. In summary, here we briefly review molecular changes underlying hypertrophic scarring following burns throughout all basic wound healing stages, i.e. during inflammation, proliferation and maturation.