Pancreatic cancer organotypics: High throughput, preclinical models for pharmacological agent evaluation.

Pancreatic cancer carries a terrible prognosis, as the fourth most common cause of cancer death in the Western world. There is clearly a need for new therapies to treat this disease. One of the reasons no effective treatment has been developed in the past decade may in part, be explained by the diverse influences exerted by the tumour microenvironment. The tumour stroma cross-talk in pancreatic cancer can influence chemotherapy delivery and response rate. Thus, appropriate preclinical in vitro models which can bridge simple 2D in vitro cell based assays and complex in vivo models are required to understand the biology of pancreatic cancer. Here we discuss the evolution of 3D organotypic models, which recapitulare the morphological and functional features of pancreatic ductal adenocarcinoma (PDAC). Organotypic cultures are a valid high throughput preclinical in vitro model that maybe a useful tool to help establish new therapies for PDAC. A huge advantage of the organotypic model system is that any component of the model can be easily modulated in a short time-frame. This allows new therapies that can target the cancer, the stromal compartment or both to be tested in a model that mirrors the in vivo situation. A major challenge for the future is to expand the cellular composition of the organotypic model to further develop a system that mimics the PDAC environment more precisely. We discuss how this challenge is being met to increase our understanding of this terrible disease and develop novel therapies that can improve the prognosis for patients.

Molecular biology of pancreatic ductal adenocarcinoma.

PURPOSE OF REVIEW: Recent advances in sequencing technology have led to a deeper and more comprehensive understanding of the molecular biology of pancreatic ductal adenocarcinoma. This timely review seeks to summarize these recent advances which will provide a foundation for future studies in the field. RECENT FINDINGS: Stereotypical genetic alterations have been identified and confirmed. However, additional alterations have highlighted the importance and complexity of a number of intracellular signaling pathways that present unique opportunities for therapeutic targeting. SUMMARY: A genetic signature of pancreatic ductal adenocarcinoma has been identified. This recent and important work is currently in the process of being applied in many clinical applications from early diagnostics to customized therapeutic regimens for this disease. A fundamental understanding of these findings will thus be of utmost importance for future research in the field and in the clinical care of patients with this lethal disease.

The ins and outs of fibroblast growth factor receptor signalling.

FGFR (fibroblast growth factor receptor) signalling plays critical roles in embryogensis, adult physiology, tissue repair and many pathologies. Of particular interest over recent years, it has been implicated in a wide range of cancers, and concerted efforts are underway to target different aspects of FGFR signalling networks. A major focus has been identifying the canonical downstream signalling pathways in cancer cells, and these are now relatively well understood. In the present review, we focus on two distinct but emerging hot topics in FGF biology: its role in stromal cross-talk during cancer progression and the potential roles of FGFR signalling in the nucleus. These neglected areas are proving to be of great interest clinically and are intimately linked, at least in pancreatic cancer. The importance of the stroma in cancer is well accepted, both as a conduit/barrier for treatment and as a target in its own right. Nuclear receptors are less acknowledged as targets, largely due to historical scepticism as to their existence or importance. However, increasing evidence from across the receptor tyrosine kinase field is now strong enough to make the study of nuclear growth factor receptors a major area of interest.

Nuclear translocation of FGFR1 and FGF2 in pancreatic stellate cells facilitates pancreatic cancer cell invasion.

Pancreatic cancer is characterised by desmoplasia, driven by activated pancreatic stellate cells (PSCs). Over-expression of FGFs and their receptors is a feature of pancreatic cancer and correlates with poor prognosis, but whether their expression impacts on PSCs is unclear. At the invasive front of human pancreatic cancer, FGF2 and FGFR1 localise to the nucleus in activated PSCs but not cancer cells. In vitro, inhibiting FGFR1 and FGF2 in PSCs, using RNAi or chemical inhibition, resulted in significantly reduced cell proliferation, which was not seen in cancer cells. In physiomimetic organotypic co-cultures, FGFR inhibition prevented PSC as well as cancer cell invasion. FGFR inhibition resulted in cytoplasmic localisation of FGFR1 and FGF2, in contrast to vehicle-treated conditions where PSCs with nuclear FGFR1 and FGF2 led cancer cells to invade the underlying extra-cellular matrix. Strikingly, abrogation of nuclear FGFR1 and FGF2 in PSCs abolished cancer cell invasion. These findings suggest a novel therapeutic approach, where preventing nuclear FGF/FGFR mediated proliferation and invasion in PSCs leads to disruption of the tumour microenvironment, preventing pancreatic cancer cell invasion.

Fibroblast growth factor family as a potential target in the treatment of hepatocellular carcinoma.

Hepatocellular cancer (HCC) is currently the third leading cause of cancer death worldwide. The prognosis of patients diagnosed with late-stage disease is dismal due to high resistance to conventional systemic therapies. The introduction of sorafenib, despite its limited efficacy, as the standard systemic therapy for advanced HCC has paved a way for targeted molecular therapies for HCC. Fibroblast growth factor (FGF) signaling plays an important role in the developing embryo and the adult. The FGF signaling pathway is often hijacked by cancer cells, including HCC. Several alterations in FGF signaling correlate with poor outcome in HCC patients, suggesting that this family of signaling molecules plays an important role in the development of HCC. Multikinase inhibitors targeting FGF signaling are currently under investigation in clinical trials. This review discusses the current understanding of the biological and clinical implications of aberrant FGF signaling in the prognosis, diagnosis, and treatment of HCC.

Ezrin expression is an independent prognostic factor in gastro-intestinal cancers.

BACKGROUND: Ezrin, a member of the ezrin-radixin-moesin (ERM) family of plasma membrane-cytoskeleton linker proteins, has been associated with metastatic behavior. METHODOLOGY: Microarrayed pathological tissues of surgically resected colorectal cancer liver metastasis (CRLM) and whole tissue sections of cancer of the ampulla of Vater (CAV) were analyzed to determine ezrin expression levels and correlation with survival. The requirement of ezrin in invasive capability was assessed using in vitro assays. RESULTS: Surgically resected CAV showing a low ezrin score have a better 5-year disease-specific survival than those showing a high ezrin score (P < 0.0001). Similarly, high ezrin expression at the invasive front of CRLM resulted in poor disease-free survival (P = 0.05). Multivariate analysis demonstrated high ezrin expression to be an independent adverse prognostic factor for CAV (hazard ratio (HR) 15.22 (95 % confidence interval (CI) 1.98-117.03), P < 0.01) and CRLM (HR 6.42 (95 % CI 1.01-52.43), P = 0.05), among other clinically relevant variables such as lymph node metastasis (for CAV) and the presence of extrahepatic disease, large hepatic metastases (>5 cm), and close surgical resection margins (<5 mm) (all for CRLM). In vitro experiments indicated that ezrin expression was vital for cellular processes such as adhesive and invasive activity. SIGNIFICANCE: High ezrin expression indicates an adverse prognosis in primary CAV and CRLM.

The integrin binding site 2 (IBS2) in the talin rod domain is essential for linking integrin beta subunits to the cytoskeleton.

Talin1 is a large cytoskeletal protein that links integrins to actin filaments through two distinct integrin binding sites, one present in the talin head domain (IBS1) necessary for integrin activation and a second (IBS2) that we have previously mapped to talin residues 1984-2113 (fragment J) of the talin rod domain (1 Tremuth, L., Kreis, S., Melchior, C., Hoebeke, J., Ronde, P., Plancon, S., Takeda, K., and Kieffer, N. (2004) J. Biol. Chem. 279, 22258-22266), but whose functional role is still elusive. Using a bioinformatics and cell biology approach, we have determined the minimal structure of IBS2 and show that this integrin binding site corresponds to 23 residues located in alpha helix 50 of the talin rod domain (residues 2077-2099). Alanine mutation of 2 highly conserved residues (L2094A/I2095A) within this alpha helix, which disrupted the alpha-helical structure of IBS2 as demonstrated by infrared spectroscopy and limited trypsin proteolysis, was sufficient to prevent in vivo talin fragment J targeting to alphaIIbbeta3 integrin in focal adhesions and to inhibit in vitro this association as shown by an alphaIIbbeta3 pulldown assay. Moreover, expression of a full-length mouse green fluorescent protein-talin LI/AA mutant in mouse talin1(-/-) cells was unable to rescue the inability of these cells to assemble focal adhesions (in contrast to green fluorescent protein-talin wild type) despite the presence of IBS1. Our data provide the first direct evidence that IBS2 in the talin rod is essential to link integrins to the cytoskeleton.