Search

Background: In pancreatic ductal adenocarcinoma (PDAC), the dense stroma rich in cancer-associated fibroblasts (CAFs) and the immunosuppressive microenvironment confer resistance to treatments. To overcome such resistance, we tested the combination of FOLFIRINOX (DNA damage-inducing chemotherapy drugs) with VE-822 (an ataxia-telangiectasia and RAD3-related inhibitor that targets DNA damage repair)., Methods: PDAC spheroid models and organoids were used to assess the combination effects. Tumour growth and the immune and fibrotic microenvironment were evaluated by immunohistochemistry, single-cell analysis and spatial proteomics in patient-derived xenograft (PDX) and orthotopic immunocompetent KPC mouse models., Results: The FOLFIRINOX and VE-822 combination had a strong synergistic effect in several PDAC cell lines, whatever their BRCA1, BRCA2 and ATM mutation status and resistance to standard chemotherapy agents. This was associated with high DNA damage and inhibition of DNA repair signalling pathways, leading to increased apoptosis. In immunocompetent and PDX mouse models of PDAC, the combination inhibited tumour growth more effectively than FOLFIRINOX alone. This was associated with tumour microenvironment remodelling, particularly decreased proportion of fibroblast activated protein-positive CAFs and increased anti-tumorigenic immune cell infiltration and interaction., Conclusion: The FOLFIRINOX and VE-822 combination is a promising strategy to improve FOLFIRINOX efficacy and overcome drug resistance in PDAC., Competing Interests: Competing interests: The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

In pancreatic ductal adenocarcinoma (PDAC), fibroblast activation leads to excessive secretion of extracellular matrix (ECM) and soluble factors that regulate tumor progression, prompting investigation into endoplasmic reticulum (ER)-resident proteins that may support this activation. We identified FKBP7, a peptidyl-prolyl isomerase in the ER, as overexpressed in PDAC stroma compared to cancer cells, and in patients with favorable prognosis. Analysis of single-cell RNA sequencing databases revealed FKBP7 expression in pancreatic stellate cells (PSCs) and cancer-associated fibroblasts (CAFs). When analyzed by immunohistochemistry on PDAC patient tissues, FKBP7 emerged as an early activation marker in the preneoplastic stroma, preceding αSMA expression, and responding to FAK- and TGFβ-induced stiffening and pro-fibrotic programs in PSCs. Functional analyses revealed that FKBP7 knockdown in PSCs enhanced contractility, Rho/FAK signaling, and secretion of pro-inflammatory cytokines as well as remodeling of type I collagen, promoting an activated phenotype and accelerating tumor growth in vivo. Conversely, FKBP7 expression supported a tumor-restraining (i.e. encapsulating) ECM characterized by type IV collagen. Mechanistically, FKBP7 interacts with BiP, and blocking this interaction instead leads to increased PSC secretion of type I collagen. Thus, FKBP7 serves as a novel PSC marker and ER regulator in a complex with BiP of the secretion of specific collagen subtypes, highlighting its potential to mediate ECM normalization and constrain PDAC tumorigenesis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. I, Corinne Bousquet and Corresponding Author for this manuscript, certify in the name of my co-Authors that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2025 The Authors. Published by Elsevier B.V. All rights reserved.)

Purpose: Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest cancers with increasing incidence. Even if progress have been made, the five-year overall survival remains lower than 10%. There is a desperate need in therapeutic improvements. In the last two decades, new in-vitro models have been developed and improved, including tridimensional-culture spheroids and organoids. However, animal studies remain mandatory in the upscaling before clinical studies. Orthotopic and syngeneic grafting is a robust model to test a drug efficiency in a tumor and its microenvironment., Methods: We described a method for orthotopic and syngeneic graft of KRAS mutated, p53 wildtype, 8305 cells in a C57BL/6J mouse model., Results: With this microsurgical method, 30 mice were grafted, 24 by a junior and six by a senior, resulting in 95,8 and 100% of (partial and total) successful tumoral implantation, respectively. Twenty mice underwent ultrasound follow-up. It was an efficient method for the tumoral growth evaluation. At day 16 after grafting, 85% of the tumors were detectable by ultrasound, and at day 22 all tumors were detected., Conclusions: The presented method appears to be a robust and reliable method for pre-clinical studies. A junior master student can provide positive results using this technique, which can be improved with training.

Cyclic adenosine monophosphate (cAMP) is a master regulator of mitochondrial metabolism but its precise mechanism of action yet remains unclear. Here, we found that a dietary saturated fatty acid (FA), palmitate increased intracellular cAMP synthesis through the palmitoylation of soluble adenylyl cyclase in cardiomyocytes. cAMP further induced exchange protein directly activated by cyclic AMP 1 (Epac1) activation, which was upregulated in the myocardium of obese patients. Epac1 enhanced the activity of a key enzyme regulating mitochondrial FA uptake, carnitine palmitoyltransferase 1. Consistently, pharmacological or genetic Epac1 inhibition prevented lipid overload, increased FA oxidation (FAO), and protected against mitochondrial dysfunction in cardiomyocytes. In addition, analysis of Epac1 phosphoproteome led us to identify two key mitochondrial enzymes of the the β-oxidation cycle as targets of Epac1, the long-chain FA acyl-CoA dehydrogenase (ACADL) and the 3-ketoacyl-CoA thiolase (3-KAT). Epac1 formed molecular complexes with the Ca 2+ /calmodulin-dependent protein kinase II (CaMKII), which phosphorylated ACADL and 3-KAT at specific amino acid residues to decrease lipid oxidation. The Epac1-CaMKII axis also interacted with the α subunit of ATP synthase, thereby further impairing mitochondrial energetics. Altogether, these findings indicate that Epac1 disrupts the balance between mitochondrial FA uptake and oxidation leading to lipid accumulation and mitochondrial dysfunction, and ultimately cardiomyocyte death., (© 2021. The Author(s).)

Solid cancer progression is dictated by neoplastic cell features and pro-tumoral crosstalks with their microenvironment. Stroma modifications, such as fibroblast activation into cancer-associated fibroblasts (CAFs) and extracellular matrix (ECM) remodeling, are now recognized as critical events for cancer progression and as potential therapeutic or diagnostic targets. The recent appreciation of the key, complex and multiple roles of the ECM in cancer and of the CAF diversity, has revolutionized the field and raised innovative but challenging questions. Here, we rapidly present CAF heterogeneity in link with their specific ECM remodeling features observed in cancer, before developing each of the impacts of such ECM modifications on tumor progression (survival, angiogenesis, pre-metastatic niche, chemoresistance, etc.), and on patient prognosis. Finally, based on preclinical studies and recent results obtained from clinical trials, we highlight key mechanisms or proteins that are, or may be, used as potential therapeutic or diagnostic targets, and we report and discuss benefits, disappointments, or even failures, of recently reported stroma-targeting strategies.

Cancer-associated fibroblasts (CAFs) are considered the most abundant type of stromal cells in pancreatic ductal adenocarcinoma (PDAC), playing a critical role in tumour progression and chemoresistance; however, a druggable target on CAFs has not yet been identified. Here we report that focal adhesion kinase (FAK) activity (evaluated based on 397 tyrosine phosphorylation level) in CAFs is highly increased compared to its activity in fibroblasts from healthy pancreas. Fibroblastic FAK activity is an independent prognostic marker for disease-free and overall survival of PDAC patients (cohort of 120 PDAC samples). Genetic inactivation of FAK within fibroblasts (FAK kinase-dead, KD) reduces fibrosis and immunosuppressive cell number within primary tumours and dramatically decreases tumour spread. FAK pharmacologic or genetic inactivation reduces fibroblast migration/invasion, decreases extracellular matrix (ECM) expression and deposition by CAFs, modifies ECM track generation and negatively impacts M2 macrophage polarization and migration. Thus, FAK activity within CAFs appears as an independent PDAC prognostic marker and a druggable driver of tumour cell invasion., (© 2020 The Authors. Published under the terms of the CC BY 4.0 license.)